Tempol augments the blunted cutaneous microvascular thermal reactivity in healthy young African Americans

Abstract

African Americans (AA) have elevated risk for cardiovascular disease relative to other populations. We hypothesized that cutaneous hyperemic response to local heating is reduced in young AA relative to CA and this is due to elevated oxidative stress. As such, ascorbic acid (a global antioxidant) and tempol (a superoxide dismutase mimetic) would improve this response in AA. Microdialysis fibers received (1) lactated Ringer's (Control), (2) 10 mm Ascorbic Acid, or (3) 10 μm 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol) at a rate of 2.0 μl min⁻¹. Cutaneous vascular conductance (CVC) was calculated as red blood cell flux/mean arterial pressure. Data were presented as a percentage of maximal CVC (%CVCmax) induced by 44°C heating plus sodium nitroprusside. Twenty-four (12 AA, 12 CA) young (23 ± 4 yrs) subjects participated. During 39°C heating %CVCmax was lower in AA at Control (CA: 65 ± 20 % vs. AA: 47 ± 15 %; P < 0.05) and Ascorbic Acid (CA: 73 ± 14 % vs. AA: 49 ± 17 %; P < 0.01). At Tempol site, there were no differences between groups. This was followed by infusion of 10 mm Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) at all sites to assess nitric oxide (NO) contribution to vasodilation during local heating. The NO contribution was lower in AA relative to CA at 39°C; however, this was restored with Tempol. These data suggest that: (1) cutaneous vasodilation to local heating is blunted in AA relative to CA. (2) elevated O₂⁻ generation attenuates NO-mediated cutaneous vasodilation in AA.

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High fat diet blunts the effects of leptin on ventilation and on carotid body activity

Abstract

Leptin plays a role in the control of breathing, acting mainly on central nervous structures. Leptin receptor is expressed in the carotid body (CB) and this finding has been associated with a putative physiological role of leptin in the regulation of CB function. Since, the CBs are implicated in energy metabolism herein we tested the effects of different concentrations of leptin administration on ventilatory parameters and on carotid sinus nerve (CSN) activity in control and high-fat (HF) diet fed rats, in order to clarify the role of leptin in ventilation control in metabolic disease states. We also investigated the expression of leptin receptors and the neurotransmitters involved in leptin signalling in the CBs. We found that in non-disease conditions, leptin increases minute ventilation both in basal and hypoxic conditions. However, in the HF model, the effect of leptin in ventilatory control is blunted. We also observed that HF rats display an increased frequency of CSN discharge in basal conditions that is not altered by leptin, in contrast to what is observed in control animals. Leptin did not modify intracellular Ca²⁺ in CB chemoreceptor cells, but it produced an increase in the release of adenosine from the whole CB. We conclude that CBs represent an important target for leptin signalling, not only to coordinate peripheral ventilatory chemoreflexive drive, but probably also to modulate metabolic variables. We also concluded that leptin signalling is mediated by adenosine release and that HF diets blunt leptin responses in the CB, compromising ventilatory adaptation.

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Candida tropicalis Isolates from Mexican Republic Exhibit High Susceptibility to Bleomycin and Variable Susceptibility to Hydrogen Peroxide

Microbial Drug Resistance , Vol. 0, No. 0.


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Characterization of Isolates Associated with Emergence of OXA-48-Producing Klebsiella pneumoniae in Croatia

Microbial Drug Resistance , Vol. 0, No. 0.


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Hospital Outbreak of a Colistin-Resistant, NDM-1- and OXA-48-Producing Klebsiella pneumoniae: High Mortality from Pandrug Resistance

Microbial Drug Resistance , Vol. 0, No. 0.


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Preoperative Evaluation is not Predictive of Transpyloric Feeding Conversion in Gastrostomy Dependent Pediatric Patients

ABSTRACTObjectives:Limited literature exists as to whether preoperative gastrostomy (GT)evaluation may predict which patients will go onto require gastrojejunostomy tube (GJ) feeding. The goal of this study was to compare the preoperative evaluations between patients maintained on GT feeds versus patients who required conversion to GJ feeds.Methods:We identified patients at Boston Children's Hospital who underwent GT placement and required GJ feeding between 2006–2012. GT patients were matched according to age, neurologic, and cardiac status with GJ converted patients. Preoperative characteristics, rates of total hospitalizations, and respiratory related admissions were reviewed.Results:79 GJ patients (median (IQR): age 15 (4.3, 55.7) months; weight 8.8 (4.6, 14.5) kg) were matched with 79 GT patients (median (IQR): age 14.6 (4.7, 55.7) months; weight 8.5 (5, 13.6) kg). Median time from GT to GJ conversion was 8 (IQR 3, 16) months. Both groups had similar rates of successful preoperative nasogastric feeding trials (GT (84.5%) vs GJ (83.1%), p = 1.0), upper GI series (GT (89.1%) vs GJ (93.2%), p = 0.73), abnormal videofluoroscopic swallow studies (GT (53.8%) vs GJ (62.2%), p = 0.4), and completion of gastric emptying studies (GT (10.1%) vs GJ (5.1%), p = 0.22). No differences were seen in preoperative hospitalization rates (p = 0.25), respiratory admissions (p = 0.36), although GJ patients had a mean reduction in the number of hospitalization of −1.5 ± 0.5 days, p 

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Endotracheal Tube Connector: Holding Breaths!

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