Development of peak oxygen uptake from 11–16 years determined using both treadmill and cycle ergometry

Abstract

Purposes

To investigate the development of peak oxygen uptake ( \(\dot{\text{O}}_{2}\) ) assessed on both a treadmill and a cycle ergometer in relation with sex and concurrent changes in age, body mass, fat-free mass (FFM), and maturity status and to evaluate currently proposed 'clinical red flags' or health-related cut-points for peak \(\dot{\text{O}}_{2}\) .

Methods

Multiplicative multilevel modelling, which enables the effects of variables to be partitioned concurrently within an allometric framework, was used to analyze the peak \(\dot{\text{O}}_{2}\) s of 138 (72 boys) students initially aged 11–14 years and tested on three annual occasions. Models were founded on 640 (340 from boys) determinations of peak \(\dot{\text{O}}_{2}\) , supported by anthropometric measures and maturity status.

Results

Mean peak \(\dot{\text{O}}_{2}\) s were 11–14% higher on a treadmill. The data did not meet the statistical assumptions underpinning ratio scaling of peak \(\dot{\text{O}}_{2}\) with body mass. With body mass appropriately controlled for boys' peak \(\dot{\text{O}}_{2}\) s were higher than girls' values and the difference increased with age. The development of peak \(\dot{\text{O}}_{2}\) was sex-specific, but within sex models were similar on both ergometers with FFM the dominant anthropometric factor.

Conclusions

Data should not be pooled for analysis but data from either ergometer can be used independently to interpret the development of peak \(\dot{\text{O}}_{2}\) in youth. On both ergometers and in both sexes, FFM is the most powerful morphological influence on the development of peak \(\dot{\text{O}}_{2}\) . 'Clinical red flags' or health-related cut-points proposed without consideration of exercise mode and founded on peak \(\dot{\text{O}}_{2}\) in ratio with body mass are fallacious.

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The histone H4K20 methyltransferase PR-Set7 fine-tunes the transcriptional activation of Wingless signaling in Drosophila

Publication date: Available online 8 January 2019

Source: Journal of Genetics and Genomics

Author(s): Yun Yu, Long Liu, Xiaojiao Li, Xingjie Hu, Haiyun Song

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Open-and-Shut Case: An Uncommon Cause of GI Bleeding

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Sessile Serrated Polyps with Synchronous Conventional Adenomas Increase Risk of Future Advanced Neoplasia

Abstract

Background

Surveillance colonoscopy guidelines following adenomas or sessile serrated adenomas/polyps (SSPs) are based on pathology features known to be associated with risk of future colorectal cancer. A synchronous conventional adenoma may increase the malignant potential of SSP, but current guidelines do not address this combination of pathologies.

Aims

The aim was to assess the risk of advanced neoplasia after SSP with or without synchronous adenoma compared to that following a conventional adenoma.

Methods

An audit was conducted on colonoscopies performed between 2000 and 2014 as part of a surveillance program. Index colonoscopy findings were classified as: low-risk SSP and high-risk SSP (size ≥ 10 mm or with cytological dysplasia) with and without synchronous adenoma; high-risk adenoma and low-risk adenoma. Risk of advanced neoplasia was determined at subsequent surveillance colonoscopies.

Results

In total, 2157 patients had adenoma or SSP found at index colonoscopy—low-risk adenoma (40%), high-risk adenoma (54%) and SSP (4%). Synchronous adenomas were seen with 47% of SSP. The median follow-up was 50.3 months (interquartile range 28.1–79.3). Compared to an index finding of low-risk adenoma, index findings of high-risk adenoma, as well as SSP with synchronous adenoma, were independent predictors of future advanced neoplasia (high-risk adenoma: hazard ratio (HR) = 2.04 (95% CI 1.70–2.45); high-risk SSP + adenoma HR = 3.20 (95% CI 1.31–7.82); low-risk SSP + adenoma: HR = 2.20 (95% CI 1.03–4.68)).

Conclusions

Synchronous adenoma increases the risk of advanced neoplasia for SSP equivalent to that seen following high-risk adenoma. Guidelines for surveillance should take into account concurrent pathologies with SSP.

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Hepatic miR-181b-5p Contributes to Glycogen Synthesis Through Targeting EGR1

Abstract

Background/Aim

The miR-181 family plays an important role in the regulation of various cellular functions. However, whether miR-181b-5p mediates hepatic insulin resistance remains unknown. In this study, we investigated the effect of miR-181b-5p on the regulation of hepatic glycogen synthesis.

Methods

The miR-181b-5p levels in the livers of diabetic mice were detected by real-time PCR. The glycogen levels and AKT/GSK pathway activation were examined in human hepatic L02 cells and HepG2 cells transfected with miR-181b-5p mimic or inhibitor. The potential target genes of miR-181b-5p were evaluated using a luciferase reporter assay and Western blot analysis. EGR1-specific siRNA and pCMV-EGR1 were used to further determine the role of miR-181b-5p in hepatic glycogen synthesis in vitro. Hepatic inhibition of miR-181b-5p in mice was performed using adeno-associated virus 8 (AAV8) vectors by tail intravenous injection.

Results

The miR-181b-5p levels were significantly decreased in the serum and livers of diabetic mice as well as the serum of type 2 diabetes patients. Importantly, inhibition of miR-181b-5p expression impaired the AKT/GSK pathway and reduced glycogenesis in hepatocytes. Moreover, upregulation of miR-181b-5p reversed high-glucose-induced suppression of glycogenesis. Further analysis revealed that early growth response 1 (EGR1) was a downstream target of miR-181b-5p. Silencing of EGR1 expression rescued miR-181b-5p inhibition-reduced AKT/GSK pathway activation and glycogenesis in hepatocytes. Hepatic inhibition of miR-181b-5p led to insulin resistance in C57BL/6 J mice.

Conclusion

We demonstrated that miR-181b-5p contributes to glycogen synthesis by targeting EGR1, thereby regulating PTEN expression to mediate hepatic insulin resistance.

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Risk Factors for Postpartum Emergency Department Visits in an Urban Population

Abstract

Objectives To identify risk factors associated with urban postpartum emergency department utilization. Methods This case–control study included 100 matched pairs of postpartum women who had delivered at a large, integrated urban medical system in Bronx, New York, in 2012–2013, with the cases having had an emergency department visit within 42 days of delivery. The cases, identified utilizing administrative and billing data, were matched 1:1 with controls by labor unit, delivery mode and date, excluding nonviable pregnancies. The controls did not have a known postpartum emergency department visit. Variables were abstracted from administrative data and chart review, and included demographics, antenatal/intrapartum/postpartum complications and neonatal intensive care unit admission. Factors associated with puerperal emergency department use were identified via univariate and multivariable analyses. Results Following conditional logistic regression, primiparity [54% vs. 32%, aOR 5.91, 95% CI 2.34–14.91], public insurance [70% vs. 56%, aOR 4.22, 95% CI 1.60–11.12], weekend delivery [30% vs. 26%, aOR 7.61, 95% CI 1.15–52.43] and delivery-related complications [47% vs. 28%, aOR 2.95, 95% CI 1.16–7.51] were associated with an increased risk of postpartum emergency department use, while women of younger ages (17–24 years old) were less likely to have postpartum emergency department use [aOR 0.23, 95% CI 0.07–0.74]. Univariate analysis of individual events within the composite variables showed an association between gestational hypertension/pre-eclampsia and postpartum emergency department use [28% vs. 13% OR 2.60, 95% CI 1.26–5.39]. Psychiatric history, social instability, preterm delivery/neonatal intensive care unit admission, pre-existing medical/antepartum conditions and prolonged postpartum stay were not associated. Conclusions for Practice Delivery-related complications, delivery timing, and certain sociodemographic factors are identifiable risk factors for increased postpartum emergency department utilization. These may be targeted for development of interventions improving puerperal care and potentially preventing emergency department visits, which are costly to the health system and disruptive to the lives of women and their families.

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Comparison of the scavenging intensity, remineralization and residence time of 210Po and 210Pb at key zones (biotic, sediment-water and hydrothermal) along the East Pacific GEOTRACES transect

Publication date: March 2019

Source: Journal of Environmental Radioactivity, Volume 198

Author(s): John Niedermiller, Mark Baskaran

Abstract

The contrasting geochemical behavior of two long-lived progeny of ²²²Rn (daughter product of ²²⁶Ra), ²¹⁰Po and ²¹⁰Pb, provide valuable insights on the extent of recycling of biogenic particulate matter and their preferential removal from the water column. We collected and analyzed 135 water samples from six vertical profiles for ²¹⁰Po and ²¹⁰Pb as well as a suite of aerosol samples for ²¹⁰Pb along the US GEOTRACES East Pacific Zonal Transect (GP16). Calculated atmospheric depositional flux of ²¹⁰Pb from the measured ²¹⁰Pb activity in aerosols exhibits an overall decrease from east to west along the cruise track. The inventories of ²¹⁰Po and ²¹⁰Pb and residence times in key zones that include biotic (upper 60 and 300 m), sediment-water (bottom 300 m) and volcanogenic (bottom 300 m at the East Pacific Rise (EPR) station) were calculated and compared. A comparison of inventories of ²¹⁰Po and ²¹⁰Pb in 500-m layers (maximum penetration depth of atmospherically-delivered ²¹⁰Pb was reported to be upper < 500 m) for all stations indicates clearly discernable disequilibrium between total (= particulate + dissolved) ²¹⁰Po and total ²¹⁰Pb, with ²¹⁰Po/²¹⁰Pb activity ratios less than 0.95 or greater than 1.05, in 63% (26 out of 41) of the 500-m layers. The observed large variations in the ²¹⁰Po/²¹⁰Pb activity ratio (AR) in 500 m layers (range: 0.79–1.32) of the whole water column is by far the largest disequilibrium in open ocean water reported when integrated over 500 m depths. However, the whole water-column ²¹⁰Po/²¹⁰Pb AR, calculated from the inventory of total ²¹⁰Po and total ²¹⁰Pb, varied between 0.97 ± 0.02 and 1.06 ± 0.02 (except in the EPR site, with 1.09 ± 0.02), indicating at or near-equilibrium for the whole water column in all five deep water stations. This contrasts with earlier claims of gross disequilibrium between ²¹⁰Po and ²¹⁰Pb in water depths >1000 m and we contend that most of these observations do not take in to account the variable extent of redistribution of ²¹⁰Po and ²¹⁰Pb in the water column due to remineralization of biogenic particulate matter and preferential scavenging of ²¹⁰Po over ²¹⁰Pb. We observed intense scavenging of ²¹⁰Po and ²¹⁰Pb in the bottom 300 m of the EPR site (attributed to discharge of high amounts of dissolved and colloidal Fe and Mn from the hydrothermal vent) and lower scavenging in the upper and bottom 300 m at the most oligotrophic station (ST-36), indicating that the scavenging intensities in bottom waters are likely coupled to the surface waters.

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