Pediatric Radiology

Magnetic resonance neurography of traumatic pediatric peripheral nerve injury: beyond birth-related brachial palsy Abstract Traumatic peripheral nerve injury occurs more frequently in the pediatric population than previously recognized. High-resolution magnetic resonance (MR) imaging in the form of MR neurography can serve as a powerful noninvasive tool for detecting and characterizing peripheral nerve injury in children. In this review article we briefly discuss optimal methods of MR neurography image acquisition, highlighting core MR sequences necessary to characterize peripheral nerve injury. In addition, we illustrate the MR neurography appearance of normal and abnormal peripheral nerves in children, with emphasis on commonly used Seddon and Sunderland classification schemes to characterize peripheral nerve injury severity. The primary and secondary features associated with peripheral nerve injury including skeletal muscle denervation are reviewed in addition to key distinctive features that can impact operative versus nonoperative management of children. We include a checklist approach to interpreting MR neurography for the assessment of peripheral nerve injury.

Correction to: European Society of Paediatric Radiology abdominal imaging task force: statement on imaging in very early onset inflammatory bowel disease The above article was published online with incorrect author name. The right spelling should be Damjana Kljucevsek instead of Damjana Kjucevsek. The correct name is presented here.

Evaluating growth failure with diffusion tensor imaging in pediatric survivors of high-risk neuroblastoma treated with high-dose cis-retinoic acid Abstract Background The survival of patients with high-risk neuroblastoma has increased with multimodal therapy, but most survivors demonstrate growth failure. Objective To assess physeal abnormalities in children with high-risk neuroblastoma in comparison to normal controls by using diffusion tensor imaging (DTI) of the distal femoral physis and adjacent metaphysis. Materials and methods We prospectively obtained physeal DTI at 3.0 T in 20 subjects (mean age: 12.4 years, 7 females) with high-risk neuroblastoma treated with high-dose cis-retinoic acid, and 20 age- and gender-matched controls. We compared fractional anisotropy (FA), normalized tract volume (cm3/cm2) and tract concentration (tracts/cm2) between the groups, in relation to height Z-score and response to growth hormone therapy. Tractography images were evaluated qualitatively. Results DTI parameters were significantly lower in high-risk neuroblastoma survivors compared to controls (P<0.01), particularly if the patients were exposed to both cis-retinoic acid and total body irradiation (P<0.05). For survivors and controls, DTI values were respectively [mean ± standard deviation]: tract concentration (tracts/cm2), 23.2±14.7 and 36.7±10.5; normalized tract volume (cm3/cm2), 0.44±0.27 and 0.70±0.21, and FA, 0.22±0.05 and 0.26±0.02. High-risk neuroblastoma survivors responding to growth hormone compared to non-responders had higher FA (0.25±0.04 and 0.18±0.03, respectively, P=0.02), and tract concentration (tracts/cm2) (31.4±13.7 and 14.8±7.9, respectively, P<0.05). FA, normalized tract volume and tract concentration were linearly related to height Z-score (R2>0.31; P<0.001). Qualitatively, tracts were nearly absent in all non-responders to growth hormone and abundant in all responders (P=0.02). Conclusion DTI shows physeal abnormalities that correlate with short stature in high-risk neuroblastoma survivors and demonstrates response to growth hormone treatment.

Functional and structural connectivity of the brain in very preterm babies: relationship with gestational age and body and brain growth Abstract Background Structural and functional changes of the brain have been reported in premature babies. Objective To evaluate the relationship of functional and structural connectivity with gestational age, body growth and brain maturation in very preterm babies. Materials and methods We studied 18 very preterm babies (gestational age: mean ± standard deviation, 29.7±1.7 weeks). We examined functional connectivity by multivariate pattern analysis of resting-state functional MRI data. We assessed structural connectivity by analysis of diffusion tensor imaging data and probabilistic tractography. Results The average functional connectivity of the medial orbitofrontal cortex with the rest of the brain was positively associated with gestational age (P<0.001). Fractional anisotropy of the right inferior fronto-occipital fasciculus was positively associated with head circumference at term-equivalent age. Structural connectivity of the inferior fronto-occipital fasciculus with the medial orbitofrontal cortex was positively associated with head circumference at term-equivalent age. Body weight at term-equivalent age was the only independent predictor of average structural connectivity of the medial orbitofrontal cortex with the rest of the brain (P=0.020). Conclusion Structural and functional connectivity of the medial orbitofrontal cortex with the rest of the brain depend on body growth and degree of prematurity, respectively.

Pediatric optic nerve and optic nerve sheath diameter on magnetic resonance imaging Abstract Background The normal values of optic nerve diameter and optic nerve sheath diameter might be beneficial in defining an abnormality such as optic nerve hypoplasia, or enlarged subarachnoid space, reflecting the state of increased intracranial pressure. Objective To study the normal optic nerve diameter and optic nerve sheath diameter on magnetic resonance imaging (MRI) in the early years of postnatal visual development from MRI of the brain. Materials and methods MRI of the brain in patients ages 4 years and younger were gathered. Forty-two studies with normal intracranial findings and a lack of history of increased intracranial pressure were retrospectively reviewed by two reviewers using axial T2-weighted images. Measurements were performed in transverse diameter perpendicular to the optic nerve at 3 mm behind the globe. Results The mean optic nerve diameter of the 77 optic nerves were 2.5 mm (95% confidence interval [CI] 2.4–2.6). The mean optic nerve sheath diameter values of the 79 optic nerve sheath complexes were 5.0 mm (95% CI 4.9–5.1). The mean±standard deviation optic nerve diameter and optic nerve sheath diameter stratified by each age groups were, respectively, 0 to <1 year: 2.3±0.40 and 4.81±0.37; 1 to <2 years: 2.6±0.2 and 5.0±0.4; 2 to <3 years: 2.4±0.3 and 4.9±0.6, and 3 to <4 years: 2.9±0.4 and 5.2±0.60 mm. Conclusion Seventy-four of the 77 measurements (96%) were of the measurements were above the threshold of 2 mm for optic nerve diameter. Seventy-seven of the 79 measurements (97%) were of the measurements were below the threshold of 6 mm for optic nerve sheath diameter.

Magnetic resonance imaging T1 relaxation times for the liver, pancreas and spleen in healthy children at 1.5 and 3 tesla Abstract Background T1 relaxation time is a potential magnetic resonance imaging (MRI) biomarker for fibrosis and inflammation of the solid abdominal organs. However, normal T1 relaxation times of the solid abdominal organs have not been defined for children. Objective The purpose of this study was to measure T1 relaxation times of the liver, pancreas and spleen in healthy children. Materials and methods This was an institutional review board-approved study of a convenience sample of prospectively recruited, healthy children ages 7 to 17 years undergoing research abdominal MRI (1.5 or 3 T) as part of a larger research study between February 2018 and October 2018. For the current study, T1 mapping was performed with a Modified Look-Locker sequence covering the upper abdomen. A single reviewer placed freehand regions of interest on the T1 parametric maps in the liver, pancreas and spleen, inclusive of as much parenchyma as possible. Student's t-tests and linear regression were used to compare T1 values by age and gender. Results Thirty-two participants were included (16 female:16 male; mean age: 12.2±3.1 years; n=16 at 1.5 T). Median T1 relaxation times (ms) per organ were liver: 581±64 (1.5 T), 783±88 (3 T); pancreas: 576±55 (1.5 T), 730±30 (3 T), and spleen: 1,172±71 (1.5 T), 1,356±87 (3 T). T1 values were not statistically significantly different between males and females. At both 1.5 and 3 T field strengths, linear regression showed no significant association between age and T1 values for the liver, pancreas and spleen. Conclusion We report normal T1 relaxation times for the liver, pancreas and spleen at 1.5 and 3 T in a cohort of healthy children.

Correction to: The value of postmortem computed tomography in paediatric natural cause of death: a Dutch observational study When first published, this article inadvertently listed the Dutch NODO group individually within the author list without specifying the names of the collaborators. The collaborators have been listed within the Acknowledgements section only. The corrected author list is presented in this Correction.

Correction to: A consensus response on the complete picture: reply to Lynøe and Eriksson The original version on this paper contained an error. The COI statement is incorrectly presented.

Correction to: The spectrum of cloacal malformations: how to differentiate each entity prenatally with fetal MRI The published version of this article unfortunately contained a mistake. Author name Mariana Z. Meyers was incorrect. The correct middle initial is given above.

Pediatric radiologists and burnout: identifying stressors and moving forward

Cell and Tissue Biology

Multinucleated Cells Resistant to Genotoxic Factors within Human Glioblastoma Cell Lines Abstract Glioblastoma tumors are characterized by a high phenotype diversity among patients and by a high cellular heterogeneity within each tumor instance. Here, we report the effects of photon irradiation of various dosage and regime onto cells of two reference (T98G and A172) and two novel (T2 and R1) human glioblastoma cell lines. In contrast to the A172 and R1 lines, where all cells were perished upon relatively low-dose irradiation, a population of resistant cells within the T98G and T2 lines survived even after a high-dose irradiation. These radio-resistant cells were large single- or multinucleated non-proliferating cells, that remained viable over one month after irradiation. The cells had markedly elevated expression levels of genes coding for factors promoting growth and angiogenesis, components of the extracellular matrix, and marker genes in-herent for mesenchymal phenotype. The expression profile of these genes in the radiation-induced growth-arrested cells T98G and Т2 was similar to that of the cell lines treated with another genotoxic factor, the fotemustine. Therefore, radio-resistant growth-arrested cells are characterized by a high activity of genes encoding proteins affecting both the tumor cells and their microenvironment.

Specific Features of the Ultrastructure and Biochemical Composition of Triticum spelta L . Leaf Mesophile Cells in the Initial Period of Stress Temperature Action Abstract Under controlled conditions, the effect of high (40°C, 2 h) and positive low (4°C, 2 h) temperatures on the ultrastructure of mesophyll cells of the leaf and the content of photosynthetic pigments, phenols, and flavonoids in 2-week-old Triticum spelta plants was studied. The ultrastructure of the mesophyll cells of the leaf of the control plants was typical: a developed thylakoid system was clearly seen that was immersed in a fine-grained stroma in the chloroplasts of regular lenticular shape. Short-term hyperthermia caused a partial destruction of thylakoid membranes. Wave-shaped packing of grana thylakoids, significant expansion of lumen intervals, disturbance of the structural bond between the grana thylacoids and stroma thylakoids was noted. With hyperthermia, the mitochondria noticeably "swelled," while the cristae membranes became less contrasting. The number of lipid droplets increased in the cytoplasm of cells. In the leaves, the content of chlorophylls and carotenoids decreased, however, the number of common phenols and flavonoids increased. Short-term hypothermia caused intense formation of plastoglobules, and an increase in the number and size of starch grains. Destruction of thylakoid membranes was not observed. Some of the mitochondria were rounded (40%), with their size being close to the control values, and some organelles were lenticular, "dumbbell," and "cup-shaped." Under hyper- and hypothermia, the T. spelta leaf mesophyll cells showed a tendency to increase the degree of chromatin condensation in the nucleus. Under hypothermia, the content and ratio of chlorophylls and carotenoids in leaves did not differ much from the control plants, and no significant quantitative changes in the total phenols and flavonoids were recorded.

Chromosomal Instability and Evolution of Transformed Phenotype in Cell Lines Selected from Senescent Rat Embryonic Fibroblasts with Rapamycin Abstract The karyotype and phenotype evolution in cell lines (Rapa) obtained by rapamycin selection from rat embryonic fibroblasts (REF) has been studied. Rapamycin, an inhibitor of mTORC1 kinase, prevents replicative aging of REF cells starting after seven to ten passages in vitro. The karyotype of the established cell lines undergoes an evolution upon their cultivation in vitro. On early passages, clonal chromosome rearrangements, more specifically trisomy of chromosome 7 and translocations t(2;7) or t(4;11), were observed. Chromosome rearrangements (CR) accumulated at late passages. Simultaneously, signs of the transformed phenotype appeared: capacity for clonal growth, a decrease in contact inhibition, and high proliferation rate in the monolayer at saturating density. The evolution of the transformed phenotype was accompanied by the loss of G1/S and/or G2/M checkpoint control. Rapa lines were characterized by accumulation of γH2AX and p53BP foci, which, however, did not colocalize. Thus indicates the accumulation of unrepaired double-strand DNA breaks (DSB). The Rapa lines are shown to express the pluripotency markers Nanog and Oct3/4. The causes of genetic and karyotype instability of Rapa lines during long-term cultivation have been discussed.

Entosis and Cell Cycle in Tumor Cell Culture Abstract Entosis is a type of cell cannibalism during which one tumor cell invades another. The fate of the inner cell can vary. It can leave the entotic vacuole, divide within it, or be subjected to lysosome-mediated degradation. The aim of our work was to determine whether MCF7 (p53+) human breast adenocarcinoma cells and A431 (p53-) human epidermoid carcinoma cells can pass through the cell cycle during entosis. The percentage of entotic cells was 1.01 ± 0.37% in MCF7 culture and 0.42 ± 0.27% in A431 culture. It was shown that inner cells, as well as outer cells, can synthesize DNA (BrdU incorporation) and enter mitosis. Morphometric analysis showed polyploidization of outer cells. This process is most pronounced in the A431 (p53–) cell line. In addition, polyploid cells may be the preferred targets of invasion in this culture. In the MCF-7 cell line, the number of G1-phase entotic cells was higher, probably due to p53-mediated cell cycle arrest or the preferred cell invasion in the G1-phase. Overall, in tumors with active p53 protein expression, the entosis contribution to polyploidy and genetic instability of tumor cells is less than in p53 tumor cells.

Intranuclear Actin Distribution at the Four- and Eight-Cell Stages of Mouse Embryo Development Abstract Intranuclear distribution of actin was studied in mouse embryos in the middle and end of the four-cell stage of development, as well as in the blastomeres of uncompacted eight-cell embryos. Actin was visualized with direct fluorescence, indirect immunofluorescence and confocal microscopy. It was found that nuclei at these stages of development contained monomeric, as well as polymeric actin, differing from conventional filamentous. The pattern of actin distribution in the nuclei at the middle-stage four-cell embryos and uncompacted eight-cell embryos was similar. Comparison of this pattern with nuclear actin distribution in the two-cell embryos that we examined previously showed that at the early stages of embryo cleavage the intranuclear actin localization was not stage-specific and was stably reproduced in the nuclei of the embryos during transition from earlier to later stage of embryogenesis. Filamentous actin that had not been found in the nuclei of middle-stage four-cell embryos was detected by fluorescent phalloidin in the nuclei of the embryos at the end of a four-cell stage of development, shortly before the beginning of the third cleavage division. The appearance of nuclear filamentous actin is possibly related to the preparation of embryos to the following cleavage division.

Mononuclear Cells of Peripheral Blood in vitro. A Model of Antipsychotic Therapy Personalization Abstract The implementation of a unified strategy for prescribing antipsychotics has proved to be an ineffective approach to the treatment of mentally ill patients. The study of the efficiency of pharmacological drugs on models mimicking the individual pathophysiology of the patient is one means of personalized (predictive) therapy. We evaluated the mRNA level for the genes of the neurotransmitters' receptors (ADR1B, HRH1, HTR2А, DRD1, DRD2, DRD4, and DRD5). These are targets of antipsychotic drugs; therefore, they can be used as the probable biomarkers of the success of the treatment of mental illnesses of schizophrenic spectrum. We used peripheral blood mononuclear cells (PBMC) in vitro as the therapeutic model. The study included 108 patients with a proved diagnosis of schizophrenia spectrum disorders, receiving a haloperidol or olanzapine as a monotherapy. The patients were divided into two groups based on their response to the pharmacotherapy (effective or ineffective). The response was estimated with psychometric analysis performed on 28 ± 2 days of the treatment. In the group with ineffective therapy, the level of expression of the studied genes in PBMC in vitro had increased with the presence of the antipsychotic drug, while, in the group of patients with positive dynamics of mental status normalization, the analyzed level of expression remained virtually unchanged. The highest significant differences for patients with different responses on the pharmacological treatment were observed for the ADR1B and HRH1 genes in the case of olanzapine therapy (Р = 0.004 and 0.038, respectively) and for the HTR2A gene in the case of haloperidol therapy (Р = 0.039). At the same time, basic levels of gene expression in non-cultivated PBMC were not associated with the patient's response to therapy. Thus, the mRNA level for genes of neurotransmission in PBMC in vitro in the presence of antipsychotics can be proposed as a biomarker for predicting the pharmacotherapy outcome for mentally ill patients.

Comparative Morphometry of Epithelial- and Fibroblast-like Type Cells in Culture Abstract Two morphological types, epithelial- and fibroblast-like, can be visually observed in cultivated cells. The first includes rounded and inactive cells. The cells of the second type have an elongated shape and filopodia-like outgrowths. It is obvious that these characteristics are largely subjectively determined; this complicates studying the biology of the cells adaptable and adapted to growth in culture. We have proposed a quantitative characteristic (EF indices) for their formalization. They can be used to estimate the percentage of the contribution of, respectively, filopodia (EF1), elongation or polarization (EF2), and the cell roundness (EF3) to the cell shape using the example of six different cell lines, it was demonstrated that EF1 = 15.4 ± 2.6, EF2 = 2.9 ± 1.9, and EF3 = 81.7 ± 3.2% for epithelial-like cells and 39.9 ± 5.9, 4.5 ± 0.4, and 55.6 ± 5.6% for fibroblast-like cells. It was concluded that, if the cells of two lines have differences in at least one of the indices, they can be assigned to different cell types.

Additional Prognostic Markers of Human Colon Adenocarcinoma Abstract— The expression of potential prognostic markers of human colon adenocarcinoma in tumor and adjacent normal tissue, as well as the relationship between their expression levels was studied. The expression of potential prognostic markers (IGFBP3, AhR, CYP1A1, CYP1B1, HIF-1α, OCT4A, OCT4B, OCT4B1) was assayed with quantitative RT-PCR (qPCR). A correlation between IGFBP3 and AhR expression was found. AhR signaling was analyzed in the primary culture of human colon adenocarcinoma BSK 8 with IGFBP3 gene knockout. It was found that the enhanced expression of AhR can be an additional diagnostic criterion for colon cancer. The correlation between the expression level of HIF-1α, IGFPB3, and OCT4 isoforms and clinic stage (TNM) was not estimated. Clones with IGFBP3 gene knockout had augmented doubling time and increased resistance to the cytostatic drug 5-ftoruracile after modulated activity of dioxin receptor with its agonist—indol-3-carbinol.

CD4+ T-Cell Cycling in HIV-Infected Patients with the Discordant Immunologic Response to the Antiretroviral Therapy Abstract— Discordant immune response to antiretroviral therapy (ART) in HIV infection is characterized by insufficient reconstitution of peripheral CD4+ T lymphocyte numbers despite suppression of virus replication. The causes of inefficient regeneration of CD4+ T cells on ART remain elusive. The paper reports the study involving two groups of HIV-positive patients: patients with discordant response to ART (n = 20) and patients with standard response to therapy (n = 21). The numbers of cycling (Ki-67+), senescent (CD57+), and exhausted (PD-1+) CD4+ T lymphocytes of varying degree of maturity have been determined in peripheral blood and lymph nodes of HIV-positive individuals. CD4+ T cell division asymmetry index after in vitro stimulation has been analyzed. Histological study of the lymph nodes of HIV-infected patients was carried out. It has been demonstrated that in the individuals with discordant immune response to ART, intensive CD4+ T cell cycling does not result in the increase in their count neither in peripheral blood, nor in the secondary lymphoid organs. At the same time, in the patients with impaired immune system recovery, increased cell proliferation is followed by the accumulation of exhausted CD4+ T lymphocytes. Moreover, patients with discordant immune response to ART revealed an asymmetric division of in vitro stimulated CD4+ T cells. The observed defects may be the cause of inefficient immune system recovery in HIV-infected patients on ART.

Analysis of NAD and NAD-Dependent Protein Deacetylation in Mouse Tissues Abstract— Nicotinamide adenine dinucleotide (NAD) plays a key role in the vital metabolic and regulatory processes in mammals. Disturbance of the NAD level regulation is associated with the development of such serious diseases as pellagra, neurodegenerative and cardiovascular disorders, diabetes, cancer and others. This paper presents an experimental approach that allows to determine the amount of NAD+ in mouse tissues using NMR spectroscopy, as well as the level of NAD+-dependent deacetylation of proteins in the cytosol and mitochondria.

Radiation and Environmental Biophysics

Correction to: Dose–responses for mortality from cerebrovascular and heart diseases in atomic bomb survivors: 1950–2003 The article Dose–responses for mortality from cerebrovascular and heart diseases in atomic bomb survivors: 1950–2003, written by Helmut Schöllnberger.

Obituary Prof. Dr. Dietrich Harder (11 February 1930–10 February 2019)

Improved identification of DNA double strand breaks: γ-H2AX-epitope visualization by confocal microscopy and 3D reconstructed images Abstract Currently, in the context of radiology, irradiation-induced and other genotoxic effects are determined by visualizing DSB-induced DNA repair through γ-H2AX immunofluorescence and direct counting of the foci by epifluorescence microscopy. This procedure, however, neglects the 3D nature of the nucleus. The aim of our study was to use confocal microscopy and 3D reconstructed images to improve documentation and analysis of γ-H2AX fluorescence signals after diagnostic examinations. Confluent, non-dividing MRC-5 lung fibroblasts were irradiated in vitro with a Cs-137 source and exposed to radiation doses up to 1000 mGy before fixation and staining with an antibody recognizing the phosphorylated histone variant γ-H2AX. The 3D distribution of γ-H2AX foci was visualized using confocal laser scanning microscopy. 3D reconstruction of the optical slices and γ-H2AX foci counting were performed using Imaris Image Analysis software. In parallel, γ-H2AX foci were counted visually by epifluorescence microscopy. In addition, whole blood was exposed ex vivo to the radiation doses from 200 to 1600 mGy. White blood cells (WBCs) were isolated and stained for γ-H2AX. In fibroblasts, epifluorescence microscopy alone visualized the entirety of fluorescence signals as integral, without correct demarcation of single foci, and at 1000 mGy yielded on average 11.1 foci by manual counting of 2D images in comparison to 36.1 foci with confocal microscopy and 3D reconstruction (p < 0.001). The procedure can also be applied for studies on WBCs. In contrast to epifluorescence microscopy, confocal microscopy and 3D reconstruction enables an improved identification of DSB-induced γ-H2AX foci, allowing for an unbiased, ameliorated quantification.

Influence of the external and internal radioactive contamination of the body and the clothes on the results of the thyroidal 131 I measurements conducted in Belarus after the Chernobyl accident—Part 2: Monte Carlo simulation of response of detectors near the thyroid Abstract This paper describes the calculation of the response of the most common types of radiation detectors that were used within the first few weeks after the Chernobyl accident to determine the activity of 131I in the thyroids of Belarusian subjects of an epidemiologic study of thyroid cancer. The radiation detectors, which were placed against the necks of the subjects, measured the exposure rates due to the emission of gamma rays resulting from the radioactive decay of 131I in their thyroids. Because of the external and internal radioactive contamination of the monitored subjects, gamma radiation from many radionuclides in various locations contributed to the exposure rates recorded by the detectors. To estimate accurately the contribution from gamma rays emitted from various internal and external parts of the body, the calibration factors of the radiation detectors, expressed in kBq per µR h− 1, were calculated, by means of Monte Carlo simulation, for external irradiation from unit activities of 17 radionuclides located on 19 parts of the body, as well as for internal irradiation from the same 17 radionuclides in the lungs, from caesium radionuclides distributed uniformly in the whole body, and from 131I in the thyroid. The calculations were performed for six body sizes, representative of the age range of the subjects. In a companion paper, the levels of external and internal contamination of the body were estimated for a variety of exposure conditions. The results presented in the two papers were combined to calculate the 131I activities in the thyroids of all 11,732 Belarusian study subjects of an epidemiologic study of thyroid cancer and, in turn, their thyroid doses.

A study of the protective actions for a hypothetical accident of the Bushehr nuclear power plant at different meteorological conditions Abstract In this work, protective actions have been studied assuming a hypothetical severe accident of the Bushehr nuclear power plant at different meteorological conditions. Simulations of the atmospheric dispersion of accidental airborne releases were performed using the RASCAL code. Total effective dose equivalent (TEDE) and thyroid dose received by members of the public living within a radius of 40 km around the reactor site were calculated for various atmospheric stability classes and weather conditions. According to the results of the dose assessment and by following the protective action guide of the Environmental Protection Agency (EPA), the critical zone and appropriate protective actions were determined depending on various metrological conditions. It was found that, for atmospheric stability class F and calm weather conditions, the maximum distance from the site of release for which TEDE is greater than the corresponding dose limit and for which sheltering or evacuation response actions are required, is 11 km. For the same weather conditions, the corresponding maximum distance for which iodine prophylaxis is required is 32 km. Based on the present simulations, it can be concluded that the metrological condition has a great influence on the radionuclide atmospheric dispersion and, consequently, on the critical zone where protective actions are required after the assumed accident condition.

Efficient parameter estimation in multiresponse models measuring radioactivity retention Abstract After incorporation of radioactive substances, workers are routinely checked by bioassays (isotopic activity excreted via urine, measurements of radionuclides retained in the whole body or in the lungs, etc.). From the results, the isotopic activity incorporated by the worker is inferred, as well as the values of other parameters related to the metabolism of the incorporated substance, using the 'response function'. This function depends on several factors and it is usually obtained by solving a system of linear differential equations, resulting from the compartmental model which describes the human body (or a part of it). The possibility of using different types of bioassays from the same worker improves estimation of some of the parameters that characterize the solution of the system of equations, specially the unknown incorporated activity to the system. The transfer coefficients are usually considered to be known, using the values that are published in the corresponding International Commission of Radiological Protection (ICRP) publication. In the present study some practical cases will be presented, and optimal design criteria are developed that allow taking the bio-samples at the most informative times. The methodology presented here requires solving the models of element distribution in the human organism as a function of time, for which the recently updated models recommended by the ICRP have been used. Initially thought for workers in facilities dealing with radioactive substances, the study results, procedures and conclusions can be applied to other clinical or laboratory settings, and to the design of action protocols in case of environmental public exposure.

Dose optimization of lithium to increase the uptake and retention of I-131 in rat thyroid Abstract The present study was undertaken to optimize the dose of lithium, with an aim to increase the retention of I-131 in the thyroid follicles while maintaining the euthyroid state. 24 female Wistar rats weighing 110 ± 20 g were segregated into four groups. Animals in group I were fed standard laboratory feed and water throughout the period of experimentation. Animals in group II, III and IV were additionally fed with lithium in the form of lithium carbonate orally, at a dose of 10 mg/kg body weight, 20 mg/kg body weight, 30 mg/kg body weight respectively. The dose of lithium was started 1 week prior to radioiodine administration and continued thereafter for another 8 days. After 7 days of lithium treatment, 0.48 MBq of carrier-free I-131 was injected intraperitoneally into each rat, of the four groups. I-131 thyroidal uptake and biokinetics, as well as serum TSH, T3, T4 levels were estimated in all the treatment groups. A significant increase in the thyroid and whole body counts was observed after 4 and 24 h of I-131 aministration in lithium treated rats, compared to control animals. An increase in thyroidal effective t1/2 and serum TSH levels, along with decrease in the levels of serum T3 and T4 was observed with a dose of 20 mg/kg or higher. In Conclusion, a Lithium dose of 10 mg/kg body weight in rats could increase the uptake of I-131 in the thyroid, without disturbing the control circulating levels of thyroid hormones.

Validation of a system of models for plutonium decorporation therapy Abstract A recently proposed system of models for plutonium decorporation (SPD) was developed using data from an individual occupationally exposed to plutonium via a wound [from United States Transuranium and Uranium Registries (USTUR) Case 0212]. The present study evaluated the SPD using chelation treatment data, urine measurements, and post-mortem plutonium activities in the skeleton and liver from USTUR Case 0269. This individual was occupationally exposed to moderately soluble plutonium via inhalation and extensively treated with chelating agents. The SPD was linked to the International Commission on Radiological Protection (ICRP) Publication 66 Human Respiratory Tract Model (HRTM) and the ICRP Publication 30 Gastrointestinal Tract model to evaluate the goodness-of-fit to the urinary excretion data and the predictions of post-mortem plutonium retention in the skeleton and liver. The goodness-of-fit was also evaluated when the SPD was linked to the ICRP Publication 130 HRTM and the ICRP Publication 100 Human Alimentary Tract Model. The present study showed that the proposed SPD was useful for fitting the entire, chelation-affected and non-affected, urine bioassay data, and for predicting the post-mortem plutonium retention in the skeleton and liver at time of death, 38.5 years after the accident. The results of this work are consistent with the conclusion that Ca-EDTA is less effective than Ca-DTPA for enhancing urinary excretion of plutonium.

Monte Carlo-based determination of radiation leakage dose around a dedicated IOERT accelerator Abstract Evaluating the stray radiation around medical electron accelerators is a mandatory issue. Surveying the radiation leakage dose is important for patients, technicians, and health physicists, due to radiation protection aspects. Consequently, radiation leakage dose around the head of a mobile-dedicated intraoperative radiotherapy accelerator (LIAC), at different electron energies and field sizes have been evaluated in this study. More specifically, the MCNPX Monte Carlo code was used to model the LIAC head, connected applicator, and employed water phantom. Radiation leakage dose around the LIAC head was calculated for different energy and field sizes through tuning the Monte Carlo results to the practically measured doses. These measurements were performed using an Advance Markus ionization chamber inside an automated MP3-XS water phantom. The good agreement between the calculated dose distributions within the water tank and corresponding dose measurements show that the simulation model of the LIAC head is appropriate for radiation leakage assessment. The obtained radiation leakage dose distribution highly depends on the electron energy and applicator diameter. With increasing the electron energy, the leakage dose decreased, while increasing the field size increased the leakage dose. It is concluded that the rate of stray radiation and leakage dose around the LIAC head in both vertical and horizontal planes were acceptable according to the recommended radiation protection criteria. To meet the recommended dose limit (100 µSv/week for controlled areas), the maximum number of patients should be kept to four patients per week inside a standard and unshielded operating room.

Thyroid doses due to Iodine-131 inhalation among Chernobyl cleanup workers Abstract Several hundred thousand individuals, called 'cleanup workers' or 'liquidators', who took part in decontamination and recovery activities between 1986 and 1990 within the 30-km zone around the Chernobyl nuclear power plant in Ukraine, were mainly exposed to external irradiation. However, those who were involved in cleanup activities during the 10-day period of atmospheric releases also received doses to the thyroid gland due to internal irradiation resulting essentially from inhalation of 131I. The paper presents the methodology and results of the calculation of individual thyroid doses for cleanup workers. The model that was used considers several factors, including the ground-level outdoor air concentrations of 131I at the locations of residence and work of the cleanup workers, the reduction of 131I activity in inhaled air associated with indoor occupancy, the time spent indoors, the breathing rate, which depends on the type of physical activity, and the possible intake of potassium iodine (KI) for iodine prophylaxis. Thyroid doses were calculated for a group of 594 cleanup workers with individual measurements of exposure rate against the neck, called 'direct thyroid measurements', that were performed from 30 April to 5 May 1986. The measured values of exposure rate were corrected to subtract the contribution of short-lived radioiodine isotopes in the thyroid to the detector response. The average thyroid dose due to 131I inhalation by the cleanup workers was estimated to be 180 mGy, while the median was 110 mGy. Most of the cleanup workers (73%) received thyroid doses ranging from 50 to 500 mGy. The highest individual dose from 131I inhalation among the cleanup workers with direct thyroid measurements was 4.5 Gy. To validate the model, the 131I activities in the thyroids that were calculated using the model were compared with those derived from the direct thyroid measurements. The mean of the ratios of measured-to-calculated activities of 131I in the thyroid was found to be 1.6 while the median of those ratios was 0.8. For 60 cleanup workers with direct thyroid measurements, a detailed description of hour-by-hour whereabouts and work history was available. For these cleanup workers the mean of the ratios of measured-to-calculated activities was found to be 1.2 and the median of those ratios was 1.0. These encouraging results suggest that the thyroid dose due to 131I inhalation could be estimated for Chernobyl cleanup workers with a reasonable degree of reliability even in the absence of direct thyroid measurements. However, this conclusion assumes that detailed information on whereabouts and work history could be obtained for those cleanup workers who were not measured.

Biology

Longitudinal Stolon Pulsations in the Colonial Hydroid Dynamena pumila (Linnaeus, 1758) Abstract It is established via time-lapse video microscopy that the zone of longitudinal extension of the stolon coenosarc in the colonial hydroid Dynamena pumila can extend over two interstitial sites (modules). The stretching occurs in the form of oscillations with a period corresponding to the growth pulsations of the stolon tip. Consequently, the growth zone is not restricted to one stolon module, and the main condition for longitudinal growth of the coenosarc appears to be the stretching created by the advancing growth tip, not only by the increasing number of cells in the growth zone, as the main cause of coenosarc elongation.

Impact of Spatial Heterogeneity on Drosophila melanogaster Adaptation to Unfavourable Food Media: The Results of an Experimental Evolution Study Abstract The spatiotemporal variability of environmental conditions is assumed to have a strong impact on the course of microevolution processes, including the efficiency of adaptation to unfavourable conditions and the probability of ecological specialization or, conversely, generalization (the acquisition of multipurpose adaptations). The experimentаl research on these effects is still at the initial stage, and the temporal, rather than spatial, heterogeneity of the environment is analyzed in most studies. We performed an evolution experiment that involved the adaptation of Drosophila melanogaster lines to two unfavourable media: a high-salt (S) medium and a starch-based (St) medium of low nutritional value. Some of the experimental lines had access to one of the two unfavourable media only (homogeneous environment), whereas the others had access to both media and could choose between them (heterogeneous environment). The control lines were reared on a normal laboratory medium (N) that provided favourable conditions for the species. The degree of adaptation of lines obtained on the S, St, and N media was assessed after one and a half years of adaptation. The reproduction efficiency (the amount of adult progeny derived from a pair of parents within a specified time interval), adult lifespan, oviposition rate, and ageing-related changes in the former were assessed. Flies reared in a heterogeneous environment were superior to those reared in a homogeneous one with regard to most adaptation parameters on all three media. The results agree with the hypothesis concerning the promotion of generalization and more efficient adaptation to unfavourable conditions upon spatial heterogeneity of the environment. The obtained data do not support the hypothesis of antagonistic pleiotropy, which leads to "evolutionary trade-offs" and a lower competitiveness of generalists than that of specialists under stable conditions.

Growth, Coenosarc Pulsations, and Hydroplasm Movement in the Colonial Hydroid Dynamena pumila (L., 1758) Placed in Flow-Through and Nonflow Cuvettes Abstract The coenosarc pulsations of the stolon and hydroplasmic flows (HFs) in the colonial hydroid Dynamena pumila (L., 1758) have been recorded in flow-through and nonflow, shallow cuvettes via time-lapse video microscopy. The water in the flow-through cuvette was refreshed during every 24 s. Each episode was video recorded for 2 h. Eleven indicators were used to compare hydroid reactions to maintenance in flowing and nonflowing water: the period and amplitude of pulsations of the stolon growing tip; the hourly stolon growth; the period and amplitude of transverse coenosarc pulsations; the period of unidirectional HF rate pulsations; the maximum velocity of HFs to and from the stolon tip; the distance of particle transfer per act of unidirectional HF; the volume of displaced hydroplasm per HF; and the percentage of the rest ratio in coenosarc pulsations and hydroplasm movement. On the whole, no significant changes in the coenosarc pulsations or in the growth and displacement of the hydroplasm were detected when they were compared sequentially in the same colonies in nonflowing and flowing water. At the same time, there were no changes in the growth, the frequency and amplitude of the transverse pulsations of the coenosarc, or the activity and extent of the hydroplasm currents. However, it was found that the period of growth pulsations increases by 20% in the regime with water exchange in comparison with the previous regime without flowing water. The period of HFs in the stolon increases by 42%, and the maximum current velocity decreases by 20% in flowing water. As a result, the calculated volume of moved hydroplasm in the stolon for one HF decreased by 30% in flow conditions.

Parasitic Manipulations of the Host Phenotype: Effects in Internal and External Environments Abstract Parasites can influence their hosts in various ways. When a parasite changes the phenotype of its host to increase its own fitness, it is called parasitic manipulation of host phenotype. Perhaps, not all parasites are manipulators, but manipulations are undoubtedly a widespread natural phenomenon and well-established scientific concept. Parasites can manipulate the host phenotype to ensure their additional safety within the host body, create optimal conditions for their growth and development, and promote transmission from one host to another. Parasitic manipulative strategies are highly diverse and tightly connected with the parasite's life cycle. The review gives insight into the most common types of manipulative strategies and discusses (i) the evolutionary advantages of these strategies, (ii) why some strategies are more common than others, and (iii) how manipulative strategies change in the course of parasite growth and development. Recently, it has become clear that parasitic manipulations can be an important factor influencing the relationships in both the parasitic infracommunity within the host and the ecosystem in general. The last two sections of the review describe the conflicts and cooperation within the parasitic infrapopulation and the role of parasitic manipulations in ecosystems. The review concludes with a short, imaginary journey into the future that discusses how climate change may influence the role of parasites and their manipulations in the ever-changing environment.

Trends of Intraspecific Differentiation in the Beaked Redfish Sebastes mentella (Scorpaenidae) from the Atlantic Ocean and Adjacent Waters Abstract Based on studies of the population structure of the beaked redfish Sebastes mentella in the Atlantic and Arctic oceans, a conclusion has been made about the existence of another, epigenetic, trend of its intraspecific differentiation, in addition to the population trend. Analysis of the vast array of our data and those available in literature, which were obtained by the methodological approaches accepted in population biology, made it possible to distinguish three isolated populations of beaked redfish: the North Atlantic, the Norwegian Barents Sea, and the Flemish Cap. The first two are subdivided into demersal and pelagic epigenetic groups that differ morphophysiologically and ecologically. One of the main factors of the epigenetic differentiation of beaked redfish is ontogenetic—individuals reach sexual maturity at different times. Based on the dynamics of the physiological condition of gonads, two groups of fish are identified: early maturing individuals that mainly inhabit the ocean pelagic zone and late-maturing fish that predominantly live in the near-bottom layer along the continental slope. In the first group, the mass maturation of redfish (50% of individuals) occurs at an FL of 29–33 cm and the age of 9–12 years; in the second group, it occurs at an FL of 35–43 cm and the age of 14–19 years. Another factor of epigenetic differentiation is biotopic; it is manifested as the association of discrete groups with different biotopes. Late-maturing redfish stay in the near-bottom layer of the continental and island slopes throughout the year, while early maturing individuals tend to live in the pelagic zone of open ocean areas. The biotopic epigenetic differentiation is closely related to the onset of return migrations from the nursery grounds of juveniles upon their reaching maturity. Juvenile beaked redfish stay in the nursery ground, which is located in the shelf and shallow coastal waters, up to the age 6–10 years. Early maturing individuals are the first to leave the juvenile grounds and move to the ocean pelagic waters. Late-maturing fish, as they grow during prolonged (up to 5–7 years) migration, are recruited to demersal aggregations in deep-sea areas on continental slopes. The complication of the species' ecological structure due to the differentiation of epigenetic groups by biotopes has led to trophic specialization and weakening of the competitive interactions between them. Their habitation in different biotopes and the physiological polymorphism of redfish have not affected the unity of species populations. In the breeding season, there is no spatiotemporal isolation between the epigenetic groups, and the demersal and pelagic aggregations are replenished by common sources.

Modeling of the Damage Sustained by Forest Coenoses and Their Destruction under the Impact of Point Contamination Sources Abstract This paper addresses novel approaches to the description of ecosystem changes under the impact of contaminants, depending on their local concentration and impact duration. It is shown that, with quite simple assumptions about the biotic effects of a contaminant, this process can be considered an environmental analog of a second-order phase transition. Data on forest ecosystems in the vicinity of major point sources of contamination (copper smelting plants) were used for the analysis and verification of the proposed model.

Analyzing the Fine-Scale Dynamics of Two Dominant Species in a Polytrichum–Myrtillus Pine Forest. II. An Inhomogeneous Markov Chain and Averaged Indices Abstract Data from six repeated observations in a Polytrichum-type Scots pine forest are used to construct a nonautonomous Markov model of fine-scale dynamics of the two dominant species, bilberry (Vaccinium myrtillus) and lingonberry (V. vitis-idaea), at the late stages of postfire succession. The model consists of five transition matrices dependent on the observation year, and transition to the average matrix results in a homogeneous model. The design of the field experiment featured a large sample size on permanent transects (2000 quadrats × 6 observations), a 5-year reexamination interval, and the use of species rooting frequency on 20 × 20 cm quadrats over 25 years. The discrete Markov chain used to model the observed process of species alternation on the quadrats consists of four states: an absence of both species from the quadrat, the presence of one species of the two, and the joint presence of both species. The model time step coincides with the interval between the observations. The data allow for a unique calibration of the transition matrix for each pair of sequential observations, and the formulas of finite Markov chain theory yield the vectors of steady-state square distributions for each of the five temporal transitions. Fluctuations in the species rooting frequency among the observations are shown to exert substantial effects on the values of certain elements in the transition matrices and the components of the corresponding steady-state vectors (for particular pairs of observations), but there are no major changes in the conclusions concerning the dominating components (dominating states of the quadrats), regardless of the fluctuations. The geometric mean of five transition matrices recapitulates the spatial and temporal characteristics of the process over the entire observation period. We show that the stable terminal outcome of species dynamics is expected to involve the following distribution of quadrats among the states: 37% of the quadrats with V. myrtillus alone, 11% with V. vitis-idaea alone, 38% quadrats with both species present, and 14% "empty" quadrats. It is shown for the first time that the share of quadrats with V. vitis-idaea alone decreases considerably in the course of succession, whereas the share of quadrats with both species growing together increases. The averaged characteristics of the cyclicity and stage duration of the fine-scale dynamics make it possible to estimate the total duration of the secondary postfire succession (to reach a nearly terminal state) at 46–50 years. The quadrats with V. vitis-idaea alone have the shortest average lifetime among the described states (9 years), and those with both V. myrtillus and V. vitis-idaea have the longest average lifetime (18 years), which is partly explained by the different lifetimes of the species' shoots.

The Relation between the Species Diversity Index and Characteristics of Organism Communities in Waterbodies Abstract Based on literature data and our own, changes in the Shannon diversity index for the communities of organisms under changing environmental factors are considered. The eutrophication and pollution of waterbodies are shown to reduce the diversity of the communities; they become simpler, and the ratio of steno- to eurybiotic species decreases.

Estuarine Ecosystems and Their Place in Natural River Mouth Complexes of the Arctic: A Case Study of the Yenisei Mouth Area Abstract The estuarine ecosystem is characterized by the mixing of seawater and freshwater with a resulting salinity of 0.5 to 22–26‰, which is preserved for no less than 2–3 weeks, and by the presence of specific brackish water species. The distinguishing features of Arctic estuarine ecosystems are a sharp thermohaline stratification of the waters and, as a consequence, a difference in the boundaries of the brackish water biota distribution near the bottom and in the pelagic zone. Note that only the bottom estuarine biocenoses are characteristic of the river mouth area. The most important factor in the Arctic estuarine ecosystems is the longitudinal migrations of the halocline, especially seasonal ones. The coincidence of the borders of distribution of the true brackish water species with the borders of hydrological and morphological regions of the Yenisei River estuary defined according to long-term observations is noteworthy. Given the relative similarity of the Arctic estuarine ecosystems in their physical, chemical, and biotic components associated with the latitudinal uniformity of the mouths, we assume the presence of this correlation in other estuarine areas as well. In this case, a single survey of the benthos may give the same result as multiyear series of hydrological observations in the regionalization of an estuarine ecosystem.

In vitro Callus as a Model System for the Study of Plant Stress-Resistance to Abiotic Factors (on the Example of Cereals) Abstract The data on various aspects of the use of cereals callus cultures in vitro as model systems for the study of the plant stress-resistance to abiotic factors are presented. The focus is on studies of in vitro calli for the assessment of plant stress-resistance to drought stress. The advantages and limitations of callus cultures in vitro are considered as experimental methods to obtain stress-resistant regenerants. The issue of studying anti-stress effects in callus cultures in vitro is analyzed. The prospects of studying the mechanisms of the action of abiotic stressors and their resistance in plants at the cellular and tissue levels in the model conditions of in vitro callus culture are shown. It is emphasized that the basis for the use of calli as model systems is both the important role of the cell in all of the morphogenetic events of the plant organism in vivo and in vitro and the similarity of responses of plants in vivo, calli in vitro, and calli regenerants in vitro and ex vitro.

Der Orthopäde

Posttraumatische Wachstumsstörung nach kindlichen distalen Radiusfrakturen mit Entwicklung einer Ulnalängenvarianz Zusammenfassung Hintergrund Frakturen des distalen Unterarms sind bei Kindern häufig. Während beim Erwachsenen mit großer Sorgfalt auf den Erhalt und die Wiederherstellung der anatomischen Handgelenkskonfiguration geachtet wird, tolerieren wir beim Heranwachsenden aufgrund des noch hohen Spontankorrekturpotenzials große Achsabweichungen und therapieren weitgehend konservativ. Im handchirurgischen Alltag sehen wir jedoch regelmäßig junge Erwachsene mit posttraumatischen Handgelenksbeschwerden. Fragestellung Heilen die kindlichen Unterarmfrakturen tatsächlich trotz Toleranz großer Achsabweichungen beschwerdefrei aus? Material und Methode Literaturrecherche, Diskussion und Einordnung der Ergebnisse. Fallbeispiel aus dem handchirurgischen Alltag. Ergebnisse Die Ulna-Plus-Varianz infolge einer posttraumatischen Radiusverkürzung ist die häufigste beschwerdehafte Langzeitfolge nach kindlicher distaler Unterarmfraktur. Bereits ab einer Varianz von >2 mm treten regelmäßig Schmerzen und Bewegungseinschränkung auf, wie auch in unserem Fallbeispiel. Diskussion Sorgsame Verlaufskontrollen nach kindlicher distaler Unterarmfraktur auch über die Konsolidierung der Fraktur hinaus sind zu empfehlen, insbesondere nach transepiphysärer radialer Osteosynthese mittels Kirschner-Draht oder Beteiligung der Wachstumsfuge. Als rekonstruktive Maßnahme sollte eine Ulnaverkürzungsosteotomie bei passender Beschwerdesymptomatik und Bildgebung bereits ab >2 mm Ulna-Plus-Varianz erwogen werden.

Der Schiefhals beim Kind Zusammenfassung Hintergrund Der Schiefhals ist eine häufige Pathologie beim neugeborenen und älteren Kind. Die Differenzialdiagnosen unterscheiden sich stark in Schwere, der Möglichkeit von Spätfolgen und ihrer Behandlung. Methodik Der Artikel gibt einen Überblick über die Differenzialdiagnostik des Schiefhalses beim Kind, die aktuelle Literatur sowie einen Einblick in unseren diagnostischen und therapeutischen Algorithmus. Ergebnisse Man unterscheidet angeborene von erworbenen und schmerzhafte von nichtschmerzhaften Schiefhaltungen. In der Regel handelt es sich um einen kongenitalen muskulären Schiefhals, mit einer geschätzten Inzidenz von 0,3–1,9 %. Die wichtigste Differenzialdiagnose des angeborenen muskulären Schiefhalses ist das Klippel-Feil-Syndrom. Erworbene Schiefhaltungen haben zum Teil schwerer wiegende Ursachen und sollten immer abgeklärt werden. Zusammenfassung Die Kenntnis der möglichen Ursachen und ihrer Behandlung ist essenziell, um dem betroffenen Kind und seiner Familie adäquat helfen zu können und etwaige Spätfolgen zu verhindern.

Hüftdysplasie – Neues und Bewährtes Zusammenfassung Hintergrund Die Hüftdysplasie ist eine der häufigsten Erkrankungen in der Kinderorthopädie. Die Behandlung hat sich mit Einführung der Sonographie wesentlich verändert. Die Diagnose und die Therapie haben sich in das frühe Säuglingsalter vorverlagert. Damit befinden wir uns seit mehr als 20 Jahren in einer Zeit, in der die Hüftdysplasiebehandlung durch die Sonographie bestimmt wird. Eine große Menge an neuen Publikationen ist hinzugekommen. Bildgebende Verfahren wie die Magnetresonanztomographie zeigen neue Aspekte auf. Mit der Arthroskopie ist ein neues operatives Verfahren hinzugekommen. Dennoch spielen viele – vor allem in der operativen Therapie – bewährte Techniken weiterhin eine große Rolle. Aktuelle Therapie In dieser Arbeit werden neue und bewährte diagnostische Verfahren sowie konservative und operative therapeutische Maßnahmen dargestellt. Dabei muss berücksichtigt werden, dass bei der Vielzahl der Literatur nicht alle Aspekte im Detail beleuchtet werden können. Die Arbeit orientiert sich vor allem an der durch ein Hüftscreening im deutschsprachigen Raum etablierten Behandlung. Aber internationale diagnostische und therapeutische Sichtweisen sollen einbezogen werden.

Endoprothetische Rekonstruktion nach interkalarer Resektion Zusammenfassung Hintergrund Nach interkalarer Resektion diaphysär gelegener Knochentumoren stellt die Rekonstruktion durch eine Diaphysenprothese eine wertvolle Behandlungsoption dar. Ziel der Arbeit Dieser Artikel soll einen umfassenden Überblick über Indikation, Technik, verfügbare Implantate, Literaturergebnisse und Alternativverfahren zum alloplastischen Segmentersatz geben. Material und Methodik Es werden eigene Erfahrungen und Ergebnisse präsentiert sowie ein Literaturüberblick, der wesentliche Arbeiten zum Thema zusammenfasst. Ergebnisse In der Literatur werden 10-Jahres-Standzeiten interkalarer Endoprothesen zwischen 64 und 80 % angegeben. Ein direkter Vergleich der Ergebnisse verschiedener Publikationen ist aufgrund kleiner Fallzahlen, unterschiedlicher Implantate und Nachbeobachtungszeiträume sowie dem heterogenen Patientenkollektiv erschwert. Biologische Alternativen zur alloplastischen Rekonstruktion sind autologe Knochentransplantate, Kallusdistraktion/Segmenttransport, allogene Knochentransplantate und die Masquelet-Technik. Innovative Tissue-Engineering-Ansätze befinden sich noch in präklinischer Erprobung. Diskussion Die kurz- bis mittelfristigen Ergebnisse für Diaphysenprothesen nach interkalarer Resektion sind zufriedenstellend und denen biologischer Verfahren aufgrund der unmittelbaren Belastbarkeit überlegen. Aufgrund potenzieller Spätkomplikationen kommen sie jedoch bis dato überwiegend in Palliativsituationen und bei älteren Patienten zum Einsatz.

Klassifikation des Wachstumspotenzials und resultierende therapeutische Konsequenzen bei Wirbelsäulendeformitäten Zusammenfassung Hintergrund Die adoleszente idiopathische Skoliose ist eine dreidimensionale Achsabweichung der Wirbelsäule mit einer Krümmung in der Frontalebene (Cobb-Winkel) von mehr als 10° ohne nachweisbare Ursache. Während den Phasen des schnellen Wachstums ist eine Verschlechterung der Skoliose im Sinne einer Zunahme des Cobb-Winkels sowie der rotatorischen Komponente wahrscheinlich. Entsprechend ist die Kenntnis der unterschiedlichen Phasen des menschlichen Wachstums für die Behandlung der adoleszenten idiopathischen Skoliose entscheidend. Klassifikation Es existieren eine Vielzahl an Klassifikationssystemen, die bei der Abschätzung des Wachstumspotenzials helfen. Im Folgenden sollen zum einen die gängigsten Klassifikationssysteme in Hinblick auf ihre flächendeckende Verfügbarkeit, Lernkurve sowie Genauigkeit in Bezug auf die Anwendung bei adoleszenten idiopathischen Skoliosen genauer betrachtet werden. Zum anderen soll, basierend auf den gemessenen Cobb-Winkeln sowie dem zu erwartenden Wachstumspotenzial, ein Therapiealgorithmus zur Behandlung der adoleszenten idiopathischen Skoliose vorgestellt werden.

Ätiologie und Bedeutung von Wachstumsstörungen der Wirbelsäule Zusammenfassung Hintergrund Der Großteil der Wachstumsstörungen der Wirbelsäule ist erworben und deren Ätiologie noch immer unbekannt. Sowohl bei den Skoliosen als auch bei den sagittalen Profilstörungen kommen die idiopathischen Formen am häufigsten vor. Ätiologie Die Ätiologie ist multifaktoriell und neben genetischen, hormonellen und mechanischen Faktoren scheinen auch Stoffwechselkomponenten mitbeteiligt zu sein. Das Progressionsrisiko einer bestehenden Deformität ist während des pubertären Wachstumsschubs besonders hoch. Entsprechend sollten in dieser vulnerablen Phase regelmäßige klinisch-radiologische Kontrollen erfolgen. Neuerdings werden unter Berücksichtigung der in den letzten Jahren gewonnenen Erkenntnisse über den Zusammenhang von Wirbelsäulen- und Thoraxwachstum und der damit verbundenen Lungenreifung die Deformitäten weniger nach ihrer Ätiologie, als vielmehr nach dem Zeitpunkt der Diagnosestellung eingeteilt. Unter dem Begriff Early-Onset-Skoliosen werden dementsprechend alle Deformitäten der Wirbelsäule subsumiert, welche vor dem 10. Lebensjahr nachgewiesen werden. Therapie Bei Versagen der so lange wie möglich einzusetzenden konservativen Therapien sollten definitive Fusionen durch Verwendung wachstumslenkender operativer Techniken hinausgezögert und damit eine den Umständen entsprechend optimale Lungenfunktion angestrebt werden.

Minimal-invasive Dekompressionsverfahren der Spinalkanalstenose Zusammenfassung Hintergrund Die lumbale Spinalkanalstenose ist eine häufige Erkrankung im höheren Lebensalter mit deutlicher Auswirkung auf die Lebensqualität betroffener Patienten. Initial kommen konservative Therapien zum Einsatz, sie führen jedoch nicht zu einer Behebung der pathologischen Veränderungen. Die operative Erweiterung des Spinalkanals ist zielführend. Fragestellung Minimalisierung operativer Zugangsstrategien bei effektiver Dekompression im Spinalkanal unter Vermeidung der Nachteile makrochirurgischer Operationstechniken, monolateraler paravertebraler Zugang für eine bilaterale intraspinale Dekompression, spezielle Operationstechniken. Material und Methoden Beschrieben werden minimal-invasive Dekompressionsverfahren unter Einsatz von Mikroskop und Endoskop. Dabei werden verschiedene operative Strategien in Abhängigkeit von dem Ausmaß (mono-, bi- und multisegmental) und der Lokalisation der Stenose (intraspinal zentral, Recessus lateralis, foraminal) vorgestellt. Ergebnisse Minimal-invasive mikroskopische und endoskopische Dekompressionsverfahren ermöglichen eine suffiziente Erweiterung des Spinalkanals. Nachteile makroskopischer Operationsmethoden (z. B. postoperative Instabilität) werden vermieden. Das Komplikationspotenzial ist teilweise ähnlich dem makroskopischer Eingriffe, jedoch in der Ausprägung deutlich reduziert. Das subjektive Outcome für die Patienten ist spürbar besser. Schlussfolgerungen Unter Hinweis auf moderne minimal-invasive Dekompressionsverfahren stellt die Operation der lumbalen Spinalkanalstenose eine sinnvolle und logische Behandlungsalternative dar, da nur operativ eine kausale Therapie der Pathologie möglich ist.

Endoprothetik an Hand und Handgelenk

Update Unfallchirurgie Hot Topic: Tumororthopädie

Daumensattelgelenkendoprothetik – eine kritische Beurteilung Zusammenfassung Die Daumensattelgelenkendoprothetik wird im Vergleich zur Trapezektomie in der Behandlung der Daumensattelgelenkarthrose immer noch weit seltener eingesetzt. Die ersten Langzeitergebnisse mit einem modernen Prothesendesign lassen jedoch weniger Komplikationen und Revisionen erwarten als mit älteren Prothesentypen. Damit rücken die Vorteile der Prothese im Sinne einer schnelleren Rehabilitation und Arbeitsfähigkeit mehr in den Vordergrund. Die höheren Kosten der Endoprothesenversorgung im Vergleich zur Trapezektomie könnten gesamtwirtschaftlich betrachtet durch den schnelleren Wiedereintritt in die Arbeit gerechtfertigt sein. Inwiefern die neuesten Prothesenentwicklungen im Sinne von Duokopfprothesen und anatomischer Oberflächenprothesen die Ergebnisse weiter verbessern, und damit die Akzeptanz der Daumensattelgelenkendoprothetik erhöht wird, bleibt mit Spannung zu beobachten.

Pediatric Critical Care Medicine

Association of Organ Dysfunction Scores and Functional Outcomes Following Pediatric Critical Illness Objectives: Short-term and long-term morbidity and mortality are common following pediatric critical illness. Severe organ dysfunction is associated with significant in-hospital mortality in critically ill children; however, the performance of pediatric organ dysfunction scores as predictors of functional outcomes after critical illness has not been previously assessed. Design: Secondary analysis of a prospective observational cohort. Setting: A multidisciplinary, tertiary, academic PICU. Patients: Patients less than or equal to 18 years old admitted between June 2012 and August 2012. Interventions: None. Measurements and Main Results: The maximum pediatric Sequential Organ Failure Assessment and Pediatric Logistic Organ Dysfunction-2 scores during admission were calculated. The Functional Status Scale score was obtained at baseline, 6 months and 3 years following discharge. New morbidity was defined as a change in Functional Status Scale greater than or equal to 3 points from baseline. The performance of organ dysfunction scores at discriminating new morbidity or mortality at 6 months and 3 years was measured using the area under the curve. Seventy-three patients met inclusion criteria. Fourteen percent had new morbidity or mortality at 6 months and 23% at 3 years. The performance of the maximum pediatric Sequential Organ Failure Assessment and Pediatric Logistic Organ Dysfunction-2 scores at discriminating new morbidity or mortality was excellent at 6 months (areas under the curves 0.9 and 0.88, respectively) and good at 3 years (0.82 and 0.79, respectively). Conclusions: Severity of organ dysfunction is associated with longitudinal change in functional status and short-term and long-term development of new morbidity and mortality. Maximum pediatric Sequential Organ Failure Assessment and Pediatric Logistic Organ Dysfunction-2 scores during critical illness have good to excellent performance at predicting new morbidity or mortality up to 3 years after critical illness. Use of these pediatric organ dysfunction scores may be helpful for prognostication of longitudinal functional outcomes in critically ill children. All authors conceptualized, designed, analyzed, drafted the article for important intellectual content, and collected the data. The authors have disclosed that they do not have any potential conflicts of interest. For information regarding this article, E-mail: travis.matics@advocatehealth.com ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

The Inadequate Oxygen Delivery Index and Low Cardiac Output Syndrome Score As predictors of Adverse Events Associated With Low Cardiac Output Syndrome Early After Cardiac Bypass Objectives: To evaluate the effectiveness of two scoring systems, the inadequate oxygen delivery index, a risk analytics algorithm (Etiometry, Boston, MA) and the Low Cardiac Output Syndrome Score, in predicting adverse events recognized as indicative of low cardiac output syndrome within 72 hours of surgery. Design: A retrospective observational pair-matched study. Setting: Tertiary pediatric cardiac ICU. Patients: Children undergoing cardiac bypass for congenital heart defects. Cases experienced an adverse event linked to low cardiac output syndrome in the 72 hours following surgery (extracorporeal membrane oxygenation, renal replacement therapy, cardiopulmonary resuscitation, and necrotizing enterocolitis) and were matched with a control patient on criteria of procedure, diagnosis, and age who experienced no such event. Interventions: None. Measurements and Main Results: Of a total 536 bypass operations in the study period, 38 patients experienced one of the defined events. Twenty-eight cases were included in the study after removing patients who suffered an event after 72 hours or who had insufficient data. Clinical and laboratory data were collected to derive scores for the first 12 hours after surgery. The inadequate oxygen delivery index was calculated by Etiometry using vital signs and laboratory data. A modified Low Cardiac Output Syndrome Score was calculated from clinical and therapeutic markers. The mean inadequate oxygen delivery and modified Low Cardiac Output Syndrome Score were compared within each matched pair using the Wilcoxon signed-rank test. Inadequate oxygen delivery correctly differentiated adverse events in 13 of 28 matched pairs, with no evidence of inadequate oxygen delivery being higher in cases (p = 0.71). Modified Low Cardiac Output Syndrome Score correctly differentiated adverse events in 23 of 28 matched pairs, with strong evidence of a raised score in low cardiac output syndrome cases (p < 0.01). Conclusions: Although inadequate oxygen delivery is an Food and Drug Administration approved indicator of risk for low mixed venous oxygen saturation, early postoperative average values were not linked with medium-term adverse events. The indicators included in the modified Low Cardiac Output Syndrome Score had a much stronger association with the specified adverse events. This work was undertaken at Great Ormond Street Hospital/UCL Institute of Child Health, which received a proportion of funding from the Department of Health's National Institute of Health Research Biomedical Research Centre's funding scheme. Drs. Ray and Peters' institutions received funding from Great Ormond Street Hospital Children's Charity (GOSHCC). Dr. Peters received funding from Faron pharmaceuticals (advisory board) and Therakind. Drs. Peters and Brown received support for article research from GOSHCC. Dr. Brown received other support from GOSHCC PICU infrastructure grant supporting Libby Rogers. The remaining authors have disclosed that they do not have any potential conflicts of interest. For information regarding this article, E-mail: samiran.ray@gosh.nhs.uk ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

Decision-Making About Intracranial Pressure Monitor Placement in Children With Traumatic Brain Injury Objectives: Little is known about how clinicians make the complex decision regarding whether to place an intracranial pressure monitor in children with traumatic brain injury. The objective of this study was to identify the decisional needs of multidisciplinary clinician stakeholders. Design: Semi-structured qualitative interviews with clinicians who regularly care for children with traumatic brain injury. Setting: One U.S. level I pediatric trauma center. Subjects: Twenty-eight clinicians including 17 ICU nurses, advanced practice providers, and physicians and 11 pediatric surgeons and neurosurgeons interviewed between August 2017 and February 2018. Interventions: None. Measurements and Main Results: Participants had a mean age of 43 years (range, 30–66 yr), mean experience of 10 years (range, 0–30 yr), were 46% female (13/28), and 96% white (27/28). A novel conceptual model emerged that related the difficulty of the decision about intracranial pressure monitor placement (y-axis) with the estimated outcome of the patient (x-axis). This model had a bimodal shape, with the most difficult decisions occurring for patients who 1) had a good opportunity for recovery but whose neurologic examination had not yet normalized or 2) had a low but uncertain likelihood of neurologically functional recovery. Emergent themes included gaps in medical knowledge and information available for decision-making, differences in perspective between clinical specialties, and ethical implications of decision-making about intracranial pressure monitoring. Experienced clinicians described less difficulty with decision-making overall. Conclusions: Children with severe traumatic brain injury near perceived transition points along a spectrum of potential for recovery present challenges for decision-making about intracranial pressure monitor placement. Clinician experience and specialty discipline further influence decision-making. These findings will contribute to the design of a multidisciplinary clinical decision support tool for intracranial pressure monitor placement in children with traumatic brain injury. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (http://journals.lww.com/pccmjournal). Dr. Bennett's institution also received funding from the National Institutes of Health (NIH) Eunice Kennedy Shriver National Institute of Child Health and Human Development and NIH/National Center for Advancing Translational Science. Drs. Bennett's and Rutebemberwa's institutions received funding from Mindsource Brain Injury Network of the Colorado Department of Human Services. Ms. Marsh's and Dr. Maertens's institutions received funding from the Colorado Department of Human Services. Dr. Hankinson's institution received funding from Colorado Traumatic Brain Injury Trust Fund. The remaining authors have disclosed that they do not have any potential conflicts of interest. For information regarding this article, E-mail: tell.bennett@ucdenver.edu ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

Development of an Antibiotic Guideline for Children With Suspected Ventilator-Associated Infections Objectives: To develop a guideline for the decision to continue or stop antibiotics at 48–72 hours after their initiation in children with suspected ventilator-associated infection. Design: Prospective, multicenter observational data collection and subsequent development of an antibiotic guideline. Setting: Twenty-two PICUs. Patients: Children less than 3 years old receiving mechanical ventilation who underwent clinical testing and initiation of antibiotics for suspected ventilator-associated infection. Interventions: None. Measurements and Main Results: Phase 1 was a prospective data collection in 281 invasively ventilated children with suspected ventilator-associated infection. The median age was 8 months (interquartile range, 4–16 mo) and 75% had at least one comorbidity. Phase 2 was development of the guideline scoring system by an expert panel employing consensus conferences, literature search, discussions with institutional colleagues, and refinement using phase 1 data. Guideline scores were then applied retrospectively to the phase 1 data. Higher scores correlated with duration of antibiotics (p < 0.001) and higher PEdiatric Logistic Organ Dysfunction 2 scores (p < 0.001) but not mortality, PICU-free days or ventilator-free days. Considering safety and outcomes based on the phase 1 data and aiming for a 25% reduction in antibiotic use, the panel recommended stopping antibiotics at 48–72 hours for guideline scores less than or equal to 2, continuing antibiotics for scores greater than or equal to 6, and offered no recommendation for scores 3, 4, and 5. The acceptability and effect of these recommendations on antibiotic use and outcomes will be prospectively tested in phase 3 of the study. Conclusions: We developed a scoring system with recommendations to guide the decision to stop or continue antibiotics at 48–72 hours in children with suspected ventilator-associated infection. The safety and efficacy of the recommendations will be prospectively tested in the planned phase 3 of the study. Members of the Pediatric Acute Lung Injury and Sepsis Investigator (PALISI) Network are listed in Appendix 1. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (http://journals.lww.com/pccmjournal). This study was supported, in part, by the Gerber Grant (number 4156) as well as the Clinical and Translational Science Awards number UL1TR000058 from the National Center for Advancing Translational Sciences (for access to Research Electronic Data Capture). Dr. Shein received funding from Accelerate Diagnostics. Drs. Karam's, Beardsley's, Karsies's, Prentice's, and Willson's institutions received funding from Gerber Foundation. Drs. Prentice and Willson received support for article research from Gerber Foundation. Dr. Tarquinio disclosed that she does not have any potential conflicts of interest. Address requests for reprints to: Steven L. Shein, MD, Division of Pediatric Critical Care, Rainbow Babies and Children's Hospital, 11100 Euclid Avenue, Cleveland OH, 44106. E-mail: Steven.shein@uhhospitals.org ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

Informed Consent for Bedside Procedures in Pediatric and Neonatal ICUs: A Nationwide Survey Objectives: Primary objectives were to discover current practices of informed consent for bedside procedures in the PICU and neonatal ICU and how trainees learn to obtain consent. We also attempted to gauge if program directors felt that one method of consent was subjectively superior to another in the way it fulfilled established ethical criteria for informed consent. Design: An online anonymous survey. Participants were asked about how and by whom informed consent is currently obtained, training practices for fellows, and attitudes about how different consent methods fulfill ethical criteria. Setting: All U.S. fellowship programs for neonatology (n = 98) and pediatric critical care (n = 66) in the fall of 2017. Subjects: Neonatal and pediatric critical care fellowship program directors. Interventions: None. Measurements and Main Results: The overall response rate was 50% (82 of 164). The most common method for obtaining consent in both ICU types was via a written, separate (procedure-specific) consent (63% neonatal ICUs, 83% PICUs); least common was verbal consent (8% neonatal ICUs and 6% PICUs). Fellows were reported as obtaining consent most often (91%), followed by mid-level practitioners (71%) and residents (66%). Residents were one-fifth as likely to obtain consent in the PICU as compared with the neonatal ICU. Sixty-three percent of fellowship directors rated their programs as "strong" or "very strong" in preparing trainees to obtain informed consent. Twenty-eight percent of fellowship directors reported no formal training on how to obtain informed consent. Conclusions: Most respondents' ICUs use separate procedure-specific written consents for common bedside procedures, although considerable variability exists. Trainees reportedly most often obtain informed consent for procedures. Although most fellowship directors report their program as strong in preparing trainees to obtain consent, this study reveals areas warranting improvement. Dr. Feltman disclosed that an internal grant supports the use of Research Electronic Data Capture (REDCap). Dr. Arnolds has disclosed that she does not have any potential conflicts of interest. This study was performed at Evanston Hospital, Evanston, IL. For information regarding this article, E-mail: marnolds@northshore.org ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

Role of IV Immunoglobulin in Indian Children With Guillain-Barré Syndrome Objectives: To evaluate the outcome of Indian children with Guillain-Barré syndrome who received IV immunoglobulin compared with those who did not receive any specific therapy. Design: Single center, prospective cross-sectional study. Setting: Tertiary care neurology teaching hospital. Patients: Children (≤ 18 yr old) with Guillain-Barré syndrome were included from a prospectively maintained Guillain-Barré syndrome registry from January 2008 to April 2017. Children were classified into acute inflammatory demyelinating polyradiculoneuropathy, acute motor axonal neuropathy, acute motor-sensory axonal neuropathy, and inexcitable motor nerves based on nerve conduction study. Interventions: Out of 138 pediatric Guillain-Barré syndrome, 50 received IV immunoglobulin and another 50 age and peak disability matched controls (who did not receive IV immunoglobulin or plasmapheresis) were selected from the same registry for comparison. Measurements and Main Results: Outcome at 3 and 6 months was defined on the basis of a 0–10 Clinical Grading Scale into complete (Clinical Grading Scale < 3), partial (Clinical Grading Scale 3–5), and poor (Clinical Grading Scale > 5) recovery. The primary outcome was proportion of patients with complete recovery at 3 and 6 months in IV immunoglobulin and non-IV immunoglobulin groups. Secondary outcomes included in-hospital deaths, duration of mechanical ventilation, and hospital stay. Subgroup analysis was done in acute motor axonal neuropathy and acute inflammatory demyelinating polyradiculoneuropathy groups. The baseline characteristics were similar except for shorter duration of illness and higher proportion of facial palsy in IV immunoglobulin group. Hospital deaths, duration of mechanical ventilation, hospital stay, and outcome at 3 and 6 months were not different between the two groups. Children with acute motor axonal neuropathy had better recovery at 6 months on IV immunoglobulin (58.3% vs 11.1%; p = 0.03), but not those with acute inflammatory demyelinating polyradiculoneuropathy (58.3% vs 72.2%; p = 0.22). In nonambulatory Guillain-Barré syndrome children, complete recovery at 6 months was similar in IV immunoglobulin and non-IV immunoglobulin group (57.4% vs 57.1%; p = 0.98). Conclusions: In Indian children with Guillain-Barré syndrome, the outcome at 6 months in IV immunoglobulin treated group was similar to non-IV immunoglobulin group. Children with acute motor axonal neuropathy responded better to IV immunoglobulin. Dr. Kalita was involved in study supervision, statistical analysis, data interpretation, and writing the article. She had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Dr. Kumar was involved in the data collection, follow-up, statistical analysis, literature search, construction of figures and tables, and writing the article. Dr. Misra was involved in planning, project supervision, and writing the article. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (http://journals.lww.com/pccmjournal). This study was approved by Institutional Ethics Committee, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The authors have disclosed that they do not have any potential conflicts of interest. For information regarding this article, E-mail: jayanteek@yahoo.com; jkalita@sgpgi.ac.in ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

Relationship Between Time to Left Atrial Decompression and Outcomes in Patients Receiving Venoarterial Extracorporeal Membrane Oxygenation Support: A Multicenter Pediatric Interventional Cardiology Early-Career Society Study Objectives: To assess the variation in timing of left atrial decompression and its association with clinical outcomes in pediatric patients supported with venoarterial extracorporeal membrane oxygenation across a multicenter cohort. Design: Multicenter retrospective study. Setting: Eleven pediatric hospitals within the United States. Patients: Patients less than 18 years on venoarterial extracorporeal membrane oxygenation who underwent left atrial decompression from 2004 to 2016. Interventions: None. Measurements and Main Results: A total of 137 patients (median age, 4.7 yr) were included. Cardiomyopathy was the most common diagnosis (47%). Cardiac arrest (39%) and low cardiac output (50%) were the most common extracorporeal membrane oxygenation indications. Median time to left atrial decompression was 6.2 hours (interquartile range, 3.8–17.2 hr) with the optimal cut-point of greater than or equal to 18 hours for late decompression determined by receiver operating characteristic curve. In univariate analysis, late decompression was associated with longer extracorporeal membrane oxygenation duration (median 8.5 vs 5 d; p = 0.02). In multivariable analysis taking into account clinical confounder and center effects, late decompression remained significantly associated with prolonged extracorporeal membrane oxygenation duration (adjusted odds ratio, 4.4; p = 0.002). Late decompression was also associated with longer duration of mechanical ventilation (adjusted odds ratio, 4.8; p = 0.002). Timing of decompression was not associated with in-hospital survival (p = 0.36) or overall survival (p = 0.42) with median follow-up of 3.2 years. Conclusions: In this multicenter study of pediatric patients receiving venoarterial extracorporeal membrane oxygenation, late left atrial decompression (≥ 18 hr) was associated with longer duration of extracorporeal membrane oxygenation support and mechanical ventilation. Although no survival benefit was demonstrated, the known morbidities associated with prolonged extracorporeal membrane oxygenation use may justify a recommendation for early left atrial decompression. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (http://journals.lww.com/pccmjournal). Supported, in part, by the CHAMPS for Mott Award, an institutional grant from the University of Michigan. Dr. Zampi's institution received funding from University of Michigan Department of Pediatrics (internal grant) and Siemens. Dr. Thiagarajan's institution received funding from Bristol Myers Squibb and Pfizer. Dr. Goldstein received funding from St. Jude Medical, Medtronic, Edwards Lifesciences, and W.L. Gore & Associates. The remaining authors have disclosed that they do not have any potential conflicts of interest. For information regarding this article, E-mail: jzampi@med.umich.edu ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

Does an Antimicrobial Time-Out Impact the Duration of Therapy of Antimicrobials in the PICU? Objectives: Our aim was to perform an antimicrobial time-out 48–72 hours after commencing therapy in order to achieve a decrease in days of therapy per 1,000 patient days for vancomycin, meropenem, and piperacillin/tazobactam in all PICU patients during an 8-month period. Design: This is a pre- and postimplementation quality improvement study. Settings: A 30-bed PICU at a tertiary children's hospital. Patients: Patients less than 21 years old admitted to the PICU from July 1, 2015, until March 31, 2016, or from July 1, 2016, until March 31, 2017, who received antibiotics for greater than 48 hours were eligible for inclusion. Intervention: An antimicrobial time-out was performed after 48–72 hours of antimicrobials for all patients in the PICU during postimplementation. Measurements and Main Results: The primary outcome measure was days of therapy per 1,000 patient-days for three target antibiotics: vancomycin, meropenem, and piperacillin/tazobactam. Ninety-five patients meeting inclusion criteria were admitted to the PICU during the pre–time-out period and 95 patients during the post–time-out period. The cohort that underwent time-outs had lower days of therapy for vancomycin (81.3 vs 138.1; p = 0.037) and meropenem (34.7 vs 67.1; p = 0.045). Total acquisition cost was 31 % lower for piperacillin/tazobactam and vancomycin and 46% for meropenem post implementation. Time-outs led to antimicrobial duration being defined 63% of the time and deescalation or discontinuation of antimicrobials 29% of the time. Conclusions: A 48–72-hour time-out process in rounds is associated with a reduction in days of therapy for antibiotics commonly used in the PICU and may lead to more appropriate usage. The time-outs are associated with discontinuation, deescalation, or duration being defined, which are key elements of Centers for Disease Control and Prevention–recommended antimicrobial stewardship programs. Dr. Morphew's institution received funding from Memorial Health Services (ongoing consultancy agreement with Morphew Consulting, LLC). Dr. Babbitt received funding from the Memorial Medical Foundation. The remaining authors have disclosed that they do not have any potential conflicts of interest. Dr. Morphew's institution received funding from Memorial Health Services (ongoing consultancy agreement with Morphew Consulting, LLC). Dr. Babbitt received funding from the Memorial Medical Foundation. The remaining authors have disclosed that they do not have any potential conflicts of interest. Address requests for reprints to: Christopher J. Babbitt, MD, FCCP, Pediatric Critical Care, Miller Children's and Women's Hospital of Long Beach, Long Beach, CA. E-mail: cbabbitt@memorialcare.org ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

Clinical Profile and Predictors of Outcome of Pediatric Acute Respiratory Distress Syndrome in a PICU: A Prospective Observational Study Objectives: To study the clinical profile, predictors of mortality, and outcomes of pediatric acute respiratory distress syndrome. Design: A prospective observational study. Setting: PICU, Advanced Pediatric Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India. Patients: All children (age > 1 mo to < 14 yr) admitted in PICU with a diagnosis of pediatric acute respiratory distress syndrome (as per Pediatric Acute Lung Injury Consensus Conference definition) from August 1, 2015, to November 2016. Interventions: None. Measurements and Main Results: Out of 1,215 children admitted to PICU, 124 (11.4%) had pediatric acute respiratory distress syndrome. Fifty-six children (45.2%) died. Median age was 2.75 years (1.0–6.0 yr) and 66.9% were male. Most common primary etiologies were pneumonia, severe sepsis, and scrub typhus. Ninety-seven children (78.2%) were invasively ventilated. On multiple logistic regressions, Lung Injury Score (p = 0.004), pneumothorax (p = 0.012), acute kidney injury at enrollment (p = 0.033), FIO2-D1 (p = 0.018), and PaO2/FIO2 ratio-D7 (p = 0.020) were independent predictors of mortality. Positive fluid balance (a cut-off value > 102.5 mL/kg; p = 0.016) was associated with higher mortality at 48 hours. Noninvasive oxygenation variables like oxygenation saturation index and saturation-FIO2 ratio were comparable to previously used invasive variables (oxygenation index and PaO2/FIO2 ratio) in monitoring the course of pediatric acute respiratory distress syndrome. Conclusions: Pediatric acute respiratory distress syndrome contributes to a significant burden in the PICU of a developing country and is associated with significantly higher mortality. Infection remains the most common etiology. Higher severity of illness scores at admission, development of pneumothorax, and a positive fluid balance at 48 hours predicted poor outcome. This work was performed at the Department of Pediatrics, Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India The authors have disclosed that they do not have any potential conflicts of interest. Address requests for reprints to: Arun Bansal, MD, FCCM, FRCPCH, Department of Pediatrics, Advanced Pediatrics Centre, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India 160012. E-mail: drarunbansal@gmail.com ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies

Gastric Residual Volume Measurement in U.K. PICUs: A Survey of Practice Objectives: Despite little evidence, the practice of routine measurement of gastric residual volume to guide both the initiation and delivery of enteral feeding in PICUs is widespread internationally. In light of increased scrutiny of the evidence surrounding this practice, and as part of a trial feasibility study, we aimed to determine enteral feeding and gastric residual volume measurement practices in U.K. PICUs. Design: An online survey to 27 U.K. PICUs. Setting: U.K. PICUs. Subjects: A clinical nurse, senior doctor, and dietician were invited to collaboratively complete one survey per PICU and send a copy of their unit guidelines on enteral feeding and gastric residual volume. Interventions: None. Measurement and Main Results: Twenty-four of 27 units (89%) approached completed the survey. Twenty-three units (95.8%; 23/24) had written feeding guidelines, and 19 units (19/23; 83%) sent their guidelines for review. More units fed continuously (15/24; 62%) than intermittently (9/24; 37%) via the gastric route as their primary feeding method. All but one PICU routinely measured gastric residual volume, regardless of the method of feeding. Eighteen units had an agreed definition of feed tolerance, and all these included gastric residual volume. Gastric residual volume thresholds for feed tolerance were either volume based (mL/kg body weight) (11/21; 52%) or a percentage of the volume of feed administered (6/21; 29%). Yet only a third of units provided guidance about the technique of gastric residual volume measurement. Conclusions: Routine gastric residual volume measurement is part of standard practice in U.K. PICUs, with little guidance provided about the technique which may impact the accuracy of gastric residual volume. All PICUs that defined feed tolerance included gastric residual volume in the definition. This is important to know when proposing a standard practice arm of any future trial of no-routine gastric residual volume measurement in critically ill children. The views expressed are those of the author (s) and not necessarily those of the NHS, the National Institute of Health Research or the Department of Health and Social Care. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (http://journals.lww.com/pccmjournal). Supported by the National Institute of Health Research (Health Technology Assessment reference 16/94/02). Drs. Tume's, Arch's, Latten's, Deja's, Roper's, Eccleson's, Hickey's, Brown's, and Gale's institutions received funding from National Institute of Health Research (NIHR) Health Technology Assessment Programme. Drs. Tume, Arch, Latten, Roper, Pathan, Eccleson, Hickey, and Brown received support for article research from NIHR Health Technology Assessment Programme. Dr. Hickey's institution received funding from NIHR Efficacy and Mechanism Evaluation Programme (EME Ref (15):/20/01), and she received funding from University of Liverpool (personal fees relating to the production of a Clinical Study Report for University Hospitals Bristol NHS Foundation Trust). Ms. Brown's institution received funding from the NIHR Doctoral Fellowship Programme. Dr. Gale's institution received funding from Medical Research Council, Chiesi Pharmaceuticals, Canadian Institute of Health Research (CIHR), and Department of Health (England); he has received support from Chiesi Pharmaceuticals to attend an educational conference; in the past 5 years, he has been an investigator on received research grants from Medical Research Council, NIHR, CIHR, Department of Health in England, Mason Medical Research Foundation, Westminster Medical School Research Trust, and Chiesi Pharmaceuticals; and he received support for article research from Research Councils UK. Dr. Valla received funding from Baxter, Fresenius Kabi, and Nutricia. Dr. Dorling's institution received funding from National Institute for Health Research and Nutricia in 2017 and 2018 for part of his salary to work as an expert advisor on a trial of enteral insulin; he disclosed he was a member of the NIHR HTA General Board (from 2017 to 2018) and the NIHR HTA Maternity, Newborn and Child Health Panel (from 2013 to 2018); and he received support for article research from NIHR. The remaining authors have disclosed that they do not have any potential conflicts of interest. For information regarding this article, E-mail: lyvonne.tume@uwe.ac.uk ©2019The Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies