Shivering heat production and core cooling during head-in and head-out immersion in 17 degrees C water

INTRODUCTION: Many cold-water scenarios cause the head to be partially or fully immersed (e.g., ship wreck survival, scuba diving, cold-water adventure swim racing, cold-water drowning, etc.). However, the specific effects of head cold exposure are minimally understood. This study isolated the effect of whole-head submersion in cold water on surface heat loss and body core cooling when the protective shivering mechanism was intact. METHODS: Eight healthy men were studied in 17 degrees C water under four conditions: the body was either insulated or exposed, with the head either out of the water or completely submersed under the water within each insulated/exposed subcondition. RESULTS: Submersion of the head (7% of the body surface area) in the body-exposed condition increased total heat loss by 11% (P < 0.05). After 45 min, head-submersion increased core cooling by 343% in the body-insulated subcondition (head-out: 0.13 +/- 0.2 degree C, head-in: 0.47 +/- 0.3 degree C; P < 0.05) and by 56% in the body-exposed subcondition (head-out: 0.40 +/- 0.3 degree C and head-in: 0.73 +/- 0.6 degree C; P < 0.05). DISCUSSION: In both body-exposed and body-insulated subconditions, head submersion increased the rate of core cooling disproportionally more than the relative increase in total heat loss. This exaggerated core-cooling effect is consistent with a head cooling induced reduction of the thermal core, which could be stimulated by cooling of thermosensitive and/or trigeminal receptors in the scalp, neck, and face. These cooling effects of head submersion are not prevented by shivering heat production.     

Equipotency of insulin glargine and regular human insulin on glucose disposal in healthy subjects following intravenous infusion

Abstract. The absolute glucose disposal of insulin glargine (Lantus) was compared to that of regular human insulin in healthy subjects (n=20) using the euglycaemic clamp technique in a single-dose, double-blind, randomized, two-way crossover design. Subjects received 30-minute intravenous infusions of insulin glargine (0.1 IU/kg) or human insulin (0.1 IU/kg) and a 20% glucose solution infused at a variable rate to maintain euglycaemia at the subjects baseline glucose level. At equal baseline blood glucose levels (4.42 mmol/l [range, 4.00–5.16 mmol/l] and 4.42 mmol/l [range, 4.01–4.94 mmol/l], respectively), the area under the glucose infusion rate (GIR) time curves from 0–6 hours (AUC_(0–6h)) was within the bioequivalence range (insulin glargine, 663.92 mg/kg; human insulin, 734.85 mg/kg). Both the time to maximum GIR and the suppression of serum C-peptide were similar with insulin glargine and human insulin. The resulting maximum serum insulin concentrations (C_max) were 151.16 µIU/ml and 202.23 µIU/ml, and the time to C_max (T_max) was 30 minutes (the duration of the infusion). The observed differences in the C_max (the mean value for insulin glargine was about 25% lower than that of human insulin) could be explained by lower cross-reactivity of insulin glargine in the human insulin radioimmunoassay. The employed intravenous route, though definitely not the intended clinical use of insulin glargine, provided the clinical evidence in healthy subjects that on a molar basis insulin glargine is equipotent to regular human insulin regarding glucose disposal.     

Prevalence of gastrointestinal symptoms in a multiracial Asian population, with particular reference to reflux-type symptoms

Objective: Data on the epidemiology of chronic gastrointestinal symptoms in the East are limited. The aims of this study were to estimate the prevalence of chronic gastrointestinal symptoms in Singapore and to determine whether ethnic differences in the prevalence of these symptoms exist.
Methods: A cross-sectional survey, using a reliable and valid questionnaire, was carried out in a race-stratified random sample of residents aged 21–95 yr (mean ± SD, 40 ± 1 yr) in a Singaporean town; 93% responded (  n = 696  ).
Results: The ethnic-adjusted prevalence of chronic abdominal pain, frequent dyspepsia, irritable bowel syndrome, chronic constipation, chronic diarrhea, and frequent reflux were 5.7% (95% confidence interval [CI], 3.3–8.1), 7.9% (95% CI, 5.0–10.8), 2.3% (95% CI, 0.8–3.9), 3.9% (95% CI, 1.9–5.9), 4.5% (95% CI, 2.3–6.7), and 1.6% (95% CI, 0.6–2.6), respectively. There were no ethnic differences in the prevalence of any of these symptom categories except for reflux-type symptoms, which were more common among Indians (7.5%; 95% CI, 4.4–11.7) than Chinese (0.8%; 95% CI, 0.1–3.0) or Malays (3.0%; 95% CI, 1.2–6.1).
Conclusion: The prevalence of all types of chronic gastrointestinal symptoms in the general population of Singapore was low compared with those in the West. Chronic gastrointestinal symptoms were equally prevalent in the three major ethnic groups except for reflux-type symptoms, which were more common among Indians than Chinese or Malays.     

Lean Mass Improvement from Nutrition Education and Protein Supplementation among Rural Indian Women Living with HIV/AIDS: Results from Cluster Randomized Factorial Trial at 18-Month Follow-Up

Loss of lean muscle mass impairs immunity and increases mortality risk among individuals with HIV/AIDS. We evaluated the relative contributions of protein supplementation and nutrition education on body composition among 600 women living with HIV/AIDS in rural Andhra Pradesh, India. We conducted a cluster randomized controlled 2 × 2 factorial trial lasting six months with follow up at twelve and eighteen months. Interventions occurred in the Nellore and Prakasam regions of Andhra Pradesh by trained village women, ASHA (Accredited Social Health Activists), and included: (1) the usual supportive care from ASHA (UC); (2) UC plus nutrition education (NE); (3) UC plus nutritional protein supplementation (NS); (4) combined UC plus NE plus NS. A Bioimpedance Analyzer Model 310e measured body composition. SAS 9.4 analyzed all data. Mixed models using repeated measures evaluated lean mass change from baseline as primary and fat weight and total weight as secondary outcomes. Lean mass change was significantly associated with NS (p = 0.0001), NE (p = 0.0001), and combined NS plus NE (p = 0.0001), with similar associations for secondary outcomes. Stronger associations for total weight were observed with greater ART adherence. Nutritional interventions may improve physiologic response to HIV. Significant increases in lean mass resulted from independent and combined protein supplementation and nutrition education.     

Guideline summary: appropriate use of tigecycline

Tigecycline, the first of a new class of broad-spectrum antibiotics (the glycylcyclines), has been licensed in South Africa for the parenteral treatment of adult patients with complicated intra-abdominal infections (cIAIs) and complicated skin and soft-tissue infections (cSSTIs). This article serves as a summary of the guideline on the appropriate use of tigecycline, published in mid-2010 as a collaborative effort by representatives of the Association of Surgeons of South Africa, the Critical Care Society of Southern Africa, the Federation of Infectious Diseases Societies of Southern Africa, the South African Thoracic Society and the Trauma Society of South Africa.