The Biochemical, Physiological, and Metabolic Evaluation of Human Subjects in a Life Support Systems Evaluator and on a Diet of Precooked Freeze Dehydrated Foods Final Report, 12 Oct. - 24 Nov. 1964

Human water, caloric, and protein requirements in simulated life support system with dietary restrictio

Extravehicular activities limitations study. Volume 1: Physiological limitations to extravehicular activity in space

This report contains the results of a comprehensive literature search on physiological aspects of EVA. Specifically, the topics covered are: (1) Oxygen levels; (2) Optimum EVA work; (3) Food and Water; (4) Carbon dioxide levels; (5) Repetitive decompressions; (6) Thermal, and (7) Urine collection. The literature was assessed on each of these topics, followed by statements on conclusions and recommended future research needs

Experimental study on coronary perfusion with selective brain cooling for direct aortic surgery

1. Retrograde coronary perfusion in combination with selective brain cooling by irrigation was investigated in dogs, in comparison with direct coronary artery perfusion. 2. High incidence of ventricular fibrillation was seen in both methods in hypothermic state. Operation at the normal temperature using extracorporeal circulation is desirable, 3. In view of the above results optimal perfusion pressure appears 30 mm Hg. in retroperfusion, while 100 mm Hg. in direct coronary artery perfusion. 4. The right ventricle anoxia is an undesirable feature in retroperfusion, while the left ventricle showed a tendency to slight anoxia in both methods.</p

Amiloride reduces portal hypertension in rat liver cirrhosis

Objective This study aimed to investigate the effect of amiloride on portal hypertension. Amiloride is known to inhibit Na(+)/H(+) exchangers on activated hepatic stellate cells. Methods Liver cirrhosis in rats was induced by bile duct ligation (BDL) or thioacetamide (TAA) administration. The effects of zymosan for Kupffer cell (KC) activation or a thromboxane (TX) analogue (U46619) were tested in isolated perfused livers of cirrhotic rats and in vivo. Downstream mechanisms were investigated using Rho kinase inhibitor (Y-27632) or amiloride. Acute and chronic effects of amiloride and canrenoate on portal pressure were compared in perfused livers and in vivo. TXB(2) efflux was measured by ELISA. The phosphorylation state of moesin (p-moesin) as an indicator of Rho kinase activity and expression of the thromboxane synthase were assessed by western blot analyses. The activity of hepatic stellate cells was analysed by western blot and staining for alpha-smooth muscle actin (alpha-SMA). Results In BDL rats, KC activation via zymosan increased portal pressure. This was attenuated by the Rho kinase inhibitor Y-27632. Increased thromboxane efflux following zymosan infusion remained unaltered by Y-27632. The infusion of amiloride attenuated zymosan- and U46619-induced increases in portal perfusion pressure. In vivo, direct administration of amiloride, but not of canrenoate, lowered portal pressure. In TAA and BDL rats, treatment with amiloride for 3 days reduced basal portal pressure and KC-induced increases in portal pressure whereas canrenoate had no effect. In livers of amiloride-treated animals, the phosphorylation state of moesin and the number of alpha-SMA positive cells were reduced. Conclusions Amiloride lowers portal pressure in rat liver cirrhosis by inhibition of intrahepatic vasocontraction. Therefore, patients with cirrhosis and portal hypertension may benefit from amiloride therapy

Joint US/USSR study: Comparison of effects of horizontal and head-down bed rest

An account is given of the results of the first joint U.S./U.S.S.R. bed rest study. The study was accomplished in two parts: A soviet part (May to June 1979) and an American part (July to August 1979). Both studies were conducted under identical conditions and provided a basis for comparison of physiologic reactions and standardizing procedures and methods. Each experiment consisted of three periods: 14 days of pre-bed rest control, 7 days of bed rest, and a 10 to 14 day recovery period. Ten males participated in each study, with five subjects experiencing horizontal bed rest and five subjects a -6 deg head-down body position. Biochemical and hormonal measurements were made of blood and urine, with particular attention to electrolyte metabolism and kidney function; cardio-pulmonary changes at rest and exercise; influence of Lower Body Negative Pressure (LBNP); and incremental exercise using a bicyle ergometer while supine and sitting. Expected moderate changes were noted to occur for various physiologic parameters. Clinical evidence pointed to the fact that head-down bed rest when compared to horizontal conditions more closely matched the conditions seen after manned spaceflight. For the most part, statistically significant differences between the two body positions were not observed

Quality evaluation of Oral Rehydration Salt (ORS) products marketed in Abuja, Nigeria

Medicine security remains one of the public health challenges in Sub-Saharan Africa as the report by World Health Organization (WHO) shows that 10.5% of medicines in low and middle-income countries worldwide are falsified or substandard. The study aimed to evaluate the quality of Oral Rehydration Salt (ORS) products sold in pharmacy outlets in Abuja, Nigeria. Seventeen different commercial brands of WHO recommended low-osmolarity ORS finished pharmaceutical products (FPP) were randomly selected from pharmacy outlets in the Federal Capital Territory (FCT) and Gwagwalada Area Council in Abuja. They were assessed for quality based on physicochemical properties and the content of active pharmaceutical ingredients in accordance with the International Pharmacopeia (IP) guidelines. The shelf lives of all the samples were valid, and they all met the visual inspection test, labelling, pH (7.4‒8.0 between23.3‒23.9°C) and moisture content (1‒9 mg/g) requirements. The content assay revealed 88.2%, 88.2%, 64.7%, 47.1%, and 35.3% compliance of the samples for glucose, chloride, citrate, sodium and potassium, respectively. Twelve (76.5%) of the brands failed at least one content assay and 8 (47%) had zero potassium content. The study underscores the need for regular, periodic post-market surveillance on essential medicines sold in the Nigerian market

Moderate exercise increases affinity of large very low density lipoproteins for hydrolysis by lipoprotein lipase

Context: Postprandial triglyceride (TG) concentration is independently associated with cardiovascular disease risk. Exercise reduces postprandial TG concentrations but the mechanisms responsible are unclear. Objective: To determine the effects of exercise on affinity of chylomicrons, large very low density lipoproteins (VLDL1) and smaller VLDL (VLDL2) for lipoprotein lipase (LPL) mediated TG hydrolysis. Design: Within-participant cross-over study. Setting: A University metabolic investigation unit. Participants: Ten overweight/obese men. Interventions: Participants undertook two oral fat tolerance tests, separated by 7–14 days, in which they had blood taken fasting and for 4 hours after a high-fat mixed meal. On the afternoon before one test, they performed a 90-minute treadmill walk at 50% maximal oxygen uptake (EX); no exercise was performed before the control test (CON). Main outcome measures: Circulating TG-rich lipoprotein concentrations; affinity of chylomicrons, VLDL1, VLDL2 for LPL-mediated TG hydrolysis. Results: Exercise significantly reduced fasting VLDL1-TG concentration (CON: 0.49(0.33–0.72) mmol.l−1, EX: 0.36(0.22–0.59) mmol.l−1, [geometric means (95% confidence interval)]; p=0.04). Time-averaged postprandial chylomicron-TG (CON: 0.55±0.10 mmol.l−1, EX: 0.39±0.08 mmol.l−1, [mean±SEM], p=0.03) and VLDL1-TG (CON: 0.85±0.13 mmol.l−1, EX: 0.66±0.10 mmol.l−1, p=0.01) concentrations were both lower in EX than CON. Affinity of VLDL1 for LPL-mediated TG hydrolysis increased by 2.2(1.3–3.7) fold (geometric mean (95% confidence interval)) (p=0.02) in the fasted state and 2.6(1.8–2.6) fold (p=0.001) postprandially. Affinity of chylomicrons and VLDL2 was not significantly different between trials. Conclusions: Exercise increases affinity of VLDL1 for LPL-mediated TG hydrolysis both fasting and postprandially. This mechanism is likely to contribute to exercise's TG-lowering effect

Safety Profile of L-Arginine Infusion in Moderately Severe Falciparum Malaria

BACKGROUND: L-arginine infusion improves endothelial function in malaria but its safety profile has not been described in detail. We assessed clinical symptoms, hemodynamic status and biochemical parameters before and after a single L-arginine infusion in adults with moderately severe malaria. METHODOLOGY AND FINDINGS: In an ascending dose study, adjunctive intravenous L-arginine hydrochloride was infused over 30 minutes in doses of 3 g, 6 g and 12 g to three separate groups of 10 adults hospitalized with moderately severe Plasmodium falciparum malaria in addition to standard quinine therapy. Symptoms, vital signs and selected biochemical measurements were assessed before, during, and for 24 hours after infusion. No new or worsening symptoms developed apart from mild discomfort at the intravenous cannula site in two patients. There was a dose-response relationship between increasing mg/kg dose and the maximum decrease in systolic (ρ = 0.463; Spearman's, p = 0.02) and diastolic blood pressure (r = 0.42; Pearson's, p = 0.02), and with the maximum increment in blood potassium (r = 0.70, p<0.001) and maximum decrement in bicarbonate concentrations (r = 0.53, p = 0.003) and pH (r = 0.48, p = 0.007). At the highest dose (12 g), changes in blood pressure and electrolytes were not clinically significant, with a mean maximum decrease in mean arterial blood pressure of 6 mmHg (range: 0–11; p<0.001), mean maximal increase in potassium of 0.5 mmol/L (range 0.2–0.7 mmol/L; p<0.001), and mean maximal decrease in bicarbonate of 3 mEq/L (range 1–7; p<0.01) without a significant change in pH. There was no significant dose-response relationship with blood phosphate, lactate, anion gap and glucose concentrations. All patients had an uncomplicated clinical recovery. CONCLUSIONS/SIGNIFICANCE: Infusion of up to 12g of intravenous L-arginine hydrochloride over 30 minutes is well tolerated in adults with moderately severe malaria, with no clinically important changes in hemodynamic or biochemical status. Trials of adjunctive L-arginine can be extended to phase 2 studies in severe malaria. TRIAL REGISTRATION: ClinicalTrials.gov NCT0014736

The Physiological and Psychological Responses to Submaximal Exercise at Different Times in Renal Disease Patients.

This study investigated cardiorespiratory, hematological, and psychological responses to acute submaximal exercise, and recovery in end stage renal disease patients. Five African-American males on hemodialysis, were randomly assigned to three exercise treatments (30 minutes on the treadmill at 60% VO\sb2 peak): pre dialysis (2 hours before), post dialysis (1 hour after), and off dialysis (24 hours after last dialysis). The cardiorespiratory (CR) variables were: ventilation (V\sb{\rm E}), oxygen consumption (VO\sb2), carbon dioxide production (VCO\sb2), respiratory exchange ratio (R), and kilocalories (KCAL/min). The hematological variables were: blood urea nitrogen (BUN), creatinine (Cr), albumin (Al), total protein (Tp), glucose (Gl), sodium (Na\sp{++}), potassium (K\sp+), hemoglobin (Hg), hematocrit (Ht), ammonium (NH\sb4), Creatine phosphokinase (CPK), lactate dehydrogenase (LDH), partial pressure of oxygen (PaO\sb2), pH, partial pressure of carbon dioxide (PaCO\sb2), bicarbonate (HCO\sb3), and saturation of oxygen (SaO\sb2). The psychological variables were: Borg\u27s rating of perceived exertion (RPE), Multiple Affect Adjective Checklist (MAACL), and Nonspecific Symptoms Questionnaire (NSQ). A randomized block design was used to analyze the data (p $\u3c$.10), with Newman-Keuls post hoc test (p $\u3c$.05). There were significant treatment effects for the following CR variables: VO\sb2, VO\sb2/kg, and kcal/min. VO\sb2/kg was significant when treatments were compared (highest post dialysis, then off dialysis, lowest pre dialysis). There was a significant difference for the time effect for glucose (baseline concentration was higher than the concentrations during and after the exercise). There were significant differences for the treatment effects in: BUN, Cr, Na\sp{++}, K\sp+, pH, LDH, CPK, and HCO\sb3 (differences were pre vs. post, and post vs. off). Only LDH and CPK were significantly different in pre vs. off. There were time effects in: shortness of breath, joint pain, cramps, and muscle weakness. Exercise relieved the symptoms. Mood score for depression had a significant treatment effect (post vs. off). This study demonstrated that these patients can safely exercise at 60% of VO\sb2 peak. Kidney disease patients should be encouraged to participate in exercise for the acute psychological effects and the long term physiological effects