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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glutamine is an essential substrate for the proper functioning of cells of the immune system. Falls in plasma glutamine concentration after exercise may have deleterious consequences for immune cell function and render the individual more susceptible to infection. The purpose of the present study was to examine changes in plasma glutamine concentration (measured using a validated enzymatic spectrophotometric method) following an acute bout of intermittent high-intensity exercise. Eight well-trained male games players took part in the study. Subjects reported to the laboratory following an overnight fast and performed a 1-h cycle exercise task consisting of 20 1-min periods at 100% maximal O2 consumption (VO2max) each separated by 2 min of recovery at 30% VO2max. Venous blood samples were taken before exercise and at 5 min, 1 h, 2.5 h, 5 h and 24 h post-exercise. Glutamine was measured by enzymatic spectrophotometric determination of the ammonia concentration before and after treatment of the plasma with glutaminase (EC 3.5.1.2). Plasma glutamine concentration did not fall in the immediate post-exercise period [pre-exercise 681 (23) microM compared with 663 (46) microM at 5 min post-exercise, mean (SEM)], but fell to 572 (35) microM at 5 h post-exercise (P < 0.05 compared with pre-exercise). Plasma lactate concentration rose to 8.8 (1.0) mM at the end of exercise and fell to 1.8 (0.4) mM at 1 h post-exercise, but plasma concentrations of free fatty acids and beta-hydroxybutyrate both rose substantially in the post-exercise period (to 240% and 400% of pre-exercise levels, respectively). The circulating leucocyte count increased significantly during exercise (P < 0.01), continued to increase in the hours following exercise and peaked at 2.5 h post-exercise (mainly due to a neutrophilia). The fall in the plasma glutamine concentration at 5 h post-exercise could be due to increased renal uptake of glutamine, which generally occurs in conditions of metabolic acidosis or due to a greater removal of glutamine from the plasma resulting from the elevated circulating leucocyte count.
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PMID:The effects of high-intensity intermittent exercise on the plasma concentrations of glutamine and organic acids. 956 94

In a randomized, crossover dietary intervention study, 12 Australians (of white descent) consumed a diet typical of low-income communities in China and an average Australian diet so that effects on fecal markers thought to be relevant to colon cancer risk could be compared. The Chinese diet contained 35.3 g starch/MJ daily [including 2 g resistant starch (RS)/MJ and 1.5 g nonstarch polysaccharides (NSPs)/MJ]; the Australian diet contained 12 g starch/MJ daily (including 0.8 g RS and 2.7 g NSPs/MJ). Subjects followed each diet for 3 wk. Serum cholesterol concentrations were significantly lower after the low-fat, high-starch Chinese diet than after the Australian diet (mean +/- SEM: 4.17 +/- 0.30 compared with 5.04 +/- 0.28 mmol/L, respectively, P < 0.05), a difference indicative of dietary compliance. Fecal pH was lower after the Chinese diet (6.51 +/- 0.04) than after the Australian diet (6.63 +/- 0.05; P < 0.05). For all other fecal markers examined, however, the Chinese diet produced less favorable changes, including lower fecal bulk (86 +/- 11 compared with 141 +/- 20 g wet wt/d, P < 0.01), slower transit through the gut (69 +/- 6 compared with 56 +/- 7 h, P = 0.06), lower fecal concentrations of short-chain fatty acids [72.8 +/- 7.3 compared with 98 +/- 7.6 mmol/L (including butyrate: 12.2 +/- 1.3 compared with 18.4 +/- 2.3 mmol/L), P < 0.05], and higher fecal concentrations of potentially damaging ammonia (540 +/- 50 compared with 450 +/- 40 mg/L, P < 0.01) and phenols (109.2 +/- 13.2 compared with 68.5 +/- 12.9 mg/L, P < 0.01). These results suggest that consumption of a high-starch diet alone is insufficient to reduce the risk of developing colon cancer.
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PMID:Modulation of fecal markers relevant to colon cancer risk: a high-starch Chinese diet did not generate expected beneficial changes relative to a Western-type diet. 970 Nov 96

The aim of this study was to investigate whether hypercortisolism in dogs with congenital portosystemic shunts disappeared after surgical closure of the shunts concomitantly with recovery from hepatic encephalopathy. We examined 22 dogs before and four weeks after partial surgical closure of a single, large congenital portosystemic shunt (PSS). Parameters measured to characterise the basal activity of the pituitary-adrenal axis were the cortisol:creatinine (c/c) ratio in home-sampled urine and total and free cortisol in plasma. The binding characteristics of cortisol binding globulin (CBG) in pooled pre- and postoperative plasma were also determined. Ammonia and bile acid concentrations were measured in plasma to characterise the liver perfusion and function. Clinical symptoms relevant to liver function, cortisol excess, and hepatic encephalopathy were recorded semiquantitatively using a standardized questionnaire. The dogs had hypercortisolism before surgery, which had normalized four weeks later. The pre- and postoperative concentrations (means +/- SEM) were, respectively, 238+/-45 nM and 126+/-19 nM for total cortisol, 15.5+/-2.6 nM and 8.4+/-1.3 nM for free cortisol in plasma, 13.4+/-4.3 x 10(-6) and 3.9+/-0.4 x 10(-6) for c/c in urine. The pre- and postoperative Bmax values of CBG were 41 and 79, and Kd values were 3.8 and 5.5. The concentrations of ammonia were 217+/-23 microM and 32+/-3.1 microM, and of bile acids 1 10+/-33 and 11.1+/-2.0 microM, respectively. We conclude that there is a close relation between portosystemic encephalopathy and hypercortisolism in dogs with PSS and that both deviations resolve completely within four weeks of closure of the shunt.
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PMID:Fast resolution of hypercortisolism in dogs with portosystemic encephalopathy after surgical shunt closure. 1008 14

A solvent-treatment technique aiming at manipulating the properties of powdered materials is reported. Potentials of the technique were assessed using sulphadiazine (SD). A suspension of the drug in a preselected solvent (5% aqueous ammonia solution) was stirred under controlled conditions. The solvent was subsequently removed and the material dried. The effect of experimental variables such as stirring speed and time, powder/solvent ratio and inclusion of additives (Tween 80, sodium chloride and PVP) on the properties of solvent treated SD was assessed. Data obtained were compared with those for SD recrystallized under identical conditions. Solvent treatment of SD in the absence of additives resulted in a limited change in crystal morphology as indicated by SEM. This was associated with improved flowability and a limited reduction in dissolution rate relative to untreated SD. On the other hand, recrystallized SD exhibited superior flowability but a considerably low dissolution rate. Solvent treatment of SD in the presence of 2% PVP produced a microgranular directly compressible material.
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PMID:Manipulation of powder characteristics by interactions at the solid-liquid interface: 1-sulphadiazine. 1042 78

A decreased ratio of branched-chain amino acids (BCAA) to aromatic amino acids (AAA) is considered an important pathogenetic factor in hepatic encephalopathy (HE). A relationship between the deranged BCAA/AAA ratio and dopaminergic dysfunction through the formation of "false" neurotransmitters has been postulated. The intermediate lobe of the pituitary is more pronounced in dogs than in humans and because it is primarily under dopaminergic inhibitory influence, it may serve as an indicator of alterations in dopaminergic neurotransmission. We investigated the effects of a diet with a high BCAA/AAA ratio (HR) and an isonitrogenous diet with a low BCAA/AAA ratio (LR) on several physical and biochemical parameters including pituitary function in dogs with portocaval shunts and 40% hepatectomy and in sham-operated pair-fed controls, in a double-blind, randomized cross-over study. Portocaval-shunted dogs had hyperammonemia (33+/-3 microM (mean +/- SEM) before and 214+/-21 after surgery)) and signs of HE. Their BCAA/AAA ratio in plasma and CSF decreased from 4.3+/-0.3 and 2.3+/-0.3 before surgery to 1.3+/-0.1 and 0.5+/-0.1 after surgery, respectively. These parameters remained unaltered in the control dogs. The consumption of the LR diet was significantly higher than consumption of the HR diet. In the portocaval-shunted dogs, plasma ammonia concentration was higher on the HR diet than on the LR diet (344+/-52 v 246+/-45) and the HE grade was worse. The BCAA/AAA ratio remained abnormal in HE dogs during the feeding of both diets. The basal and haloperidol-stimulated release of alpha-melanotropin and cortisol in plasma were not significantly different between or within groups during any period. In contrast, urinary cortisol excretion was increased in the HE dogs after surgery (urinary cortisol:creatinine ratio (x10(-6)) 8.5+/-1.4 before and 30.4+/-8.9 after surgery). The basal plasma concentration of adrenocorticotropin in HE dogs was decreased after surgery (68.3+/-10.2 ng/L before and 40.8+/-4.4 after surgery). This indicates a non-pituitary-dependent hyperresponsiveness of the adrenals. We conclude from these results that chronic HE in dogs is not associated with an abnormal dopaminergic neurotransmission at least at the level of the pituitary, and that it is not the content of the dietary neutral amino acids but rather the total protein intake that may have a beneficial effect on HE.
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PMID:Effects of a branched-chain amino acid-enriched diet on chronic hepatic encephalopathy in dogs. 1048 12

In this study we examined the time course of changes in the plasma concentration of oxypurines [hypoxanthine (Hx), xanthine and urate] during prolonged cycling to fatigue. Ten subjects with an estimated maximum oxygen uptake (VO2(max)) of 54 (range 47-67) ml x kg(-1) x min(-1) cycled at [mean (SEM)] 74 (2)% of VO2(max) until fatigue [79 (8) min]. Plasma levels of oxypurines increased during exercise, but the magnitude and the time course varied considerably between subjects. The plasma concentration of Hx ([Hx]) was 1.3 (0.3) micromol/l at rest and increased eight fold at fatigue. After 60 min of exercise plasma [Hx] was >10 micromol/l in four subjects, whereas in the remaining five subjects it was <5 micromol/l. The muscle contents of total adenine nucleotides (TAN = ATP+ADP+AMP) and inosine monophosphate (IMP) were measured before and after exercise in five subjects. Subjects with a high plasma [Hx] at fatigue also demonstrated a pronounced decrease in muscle TAN and increase in IMP. Plasma [Hx] after 60 min of exercise correlated significantly with plasma concentration of ammonia ([NH(3)], r = 0.90) and blood lactate (r = 0.66). Endurance, measured as time to fatigue, was inversely correlated to plasma [Hx] at 60 min (r = -0.68, P < 0.05) but not to either plasma [NH(3)] or blood lactate. It is concluded that during moderate-intensity exercise, plasma [Hx] increases, but to a variable extent between subjects. The present data suggest that plasma [Hx] is a marker of adenine nucleotide degradation and energetic stress during exercise. The potential use of plasma [Hx] to assess training status and to identify overtraining deserves further attention.
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PMID:Plasma hypoxanthine and ammonia in humans during prolonged exercise. 1050 75

Eight female games players (GP) and eight female endurance athletes (EA) ran intermittently at high-intensity and for prolonged periods in hot (30 degrees C) and moderate (16 degrees C) ambient temperatures. The subjects performed a two-part (A, B) test based on repeated 20-m shuttle runs. Part A comprised 60 m of walking, a maximal 15-m sprint, 60 m of cruising (90% maximal oxygen uptake, VO(2max)) and 60 m of jogging (45% VO(2max)) repeated for 75 min with a 3-min rest every 15 min. Part B involved an exercise and rest pattern of 60-s running at 100% VO(2max) and 60-s rest which was continued until fatigue. Although the GP and EA did not respond differently in terms of distances completed, performance was 25 (SEM 4)% less (main effect trial, P < 0.01) in the hot (HT) compared with the moderate trial (MT). Sprints of 15 m took longer to complete in the heat (main effect, trial, P < 0.01), and sprint performance declined during HT but not MT (interaction, trial x time, P < 0.01). A very high correlation was found between the rate of rise in rectal temperature in HT and the distance completed [GP, r =-0.94, P < 0. 01; EA (n = 7), r = -0.93, P < 0.01]. Blood lactate [La(-) ](b) and plasma ammonia [NH(3)](p1) concentrations were higher for GP than EA, but were similar in HT and MT [La(-) ](b), HT: GP vs EA, 8.0 (SEM 0. 9) vs 4.9 (SEM 1.1) mmol x l(-1); MT: GP vs EA, 8.0 (SEM 1.3) vs 4.4 (SEM 1.2) mmol x l(-1); interaction, group x time, P < 0.01; [NH(3)](p1), HT: GP vs EA, 70.1 (SEM 12.7) vs 43.2 (SEM 6.1) mmol x l(-1); MT: GP vs EA, 76.8 (SEM 8.8) vs 32.5 (SEM 3.8) micromol x l(-1); interaction, group x time, P < 0.01. Ad libitum water consumption was higher in HT [HT: GP vs EA, 18.9 (SEM 2.9) vs 13.5 (SEM 1.7) ml x kg(-1) x h(-1); MT: GP vs EA, 12.7 (SEM 3.7) vs 8.5 (SEM 1.5) ml x kg(-1) x h(-1); main effect, group, n.s.; main effect, trial, P < 0.01]. These results would suggest that elevated body temperature is probably the key factor limiting performance of prolonged, intermittent, high-intensity running when the ambient temperature is high, but not because of its effect on the metabolic responses to exercise.
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PMID:Physiological and metabolic responses of female games and endurance athletes to prolonged, intermittent, high-intensity running at 30 degrees and 16 degrees C ambient temperatures. 1055 71

Aim of the study was to evaluate treatment efficacy and safety of a scaled-up version of our porcine hepatocytes based BAL system in pigs with complete liver ischemia (LIS). Thirty-one pigs underwent total devascularization of the liver (LIS) by termino-lateral porta-caval shunts and sutures around the bile duct, the common hepatic and gastroduodenal arteries and their accessory branches. The hepato-duodenal ligament was completely transected. Four experimental groups were studied: the first control group (LIS Control, n = 10) received glucose infusion only, the second control group (LIS Plasmapheresis, n = 8) was connected to a centrifugal plasma-separator with a bottle representing the bioreactor volume, the third control group (LIS Empty-BAL, n = 5) received BAL treatment without cells, and the treated group (LIS Cell-BAL, n = 8) was connected for a maximum period of 24 hours to our scaled-up BAL seeded with around 14 billion viable primary porcine hepatocytes. BAL treatment significantly prolonged life in large animals (approximately 35 kg) with complete LIS (Controls, mean +/- SEM: 33.1 +/- 3 h, Cell-BAL: 51.1 +/- 3.4 h; p = 0.001; longest survivor 63 h). In addition, blood ammonia and total bilirubin levels decreased significantly, indicating metabolic activity of porcine hepatocytes in the bioreactor. No significant differences were noticed among the three control groups, indicating that there was no device effect and that the plasmapheresis procedure was well tolerated. No important adverse effects were observed.
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PMID:Significantly improved survival time in pigs with complete liver ischemia treated with a novel bioartificial liver. 1058 35

Failures of small internal diameter vascular grafts have been caused by the lack of a stable endothelial lining to form on their artificial surfaces. Polymer surfaces can be optimized by means of proper treatment to allow a homogeneous and uniform coverage in artificial prosthesis applications. Several solutions were studied to improve cell attachment and growth on artificial materials. In the present study, polyethyleneterephthalate (PET) surfaces were treated by plasma processes with oxygen and ammonia and also in the presence of a gas mixture to verify the effect of functional groups grafting onto the endothelial cell growth. Related surface chemical modifications were investigated by X-ray photoelectron spectroscopy (XPS). Then using cytotoxicity and cytocompatibility tests, the biocompatibility of the modified PET surfaces was assessed by studying the behavior of human umbilical vein endothelial cells (HUVEC). The results showed that plasma-treated PET samples have no toxic effect on HUVEC. The cytocompatibility tests revealed an increase in cell growth with incubation time and the presence of well-spread and flattened cells (SEM analyses). Thus it is reported that plasma treatments can improve PET biocompatibility to HUVEC.
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PMID:Plasma-treated PET surfaces improve the biocompatibility of human endothelial cells. 1088 99

Oxygen consumption was measured in five Dermophis mexicanus and averaged (+/- SEM) 0.047 +/- 0.004 ml O2 g(-1) x h(-1). Carbon dioxide production averaged 0.053 +/- 0.005 ml CO2 g(-1) x h(-1) in the same five animals 1 week later. This metabolic rate is similar to metabolic rates of other Gymnophionans but lower than metabolic rates reported for Anurans and Urodeles. Total nitrogen excretion averaged 1.37 micromol N g(-1) x h(-1) which is higher than that found for other amphibians. Of this, 82.5% (1.13 micromol N g(-1) x h(-1)) was in the form of urea while 17.5% (0.24 micromol N g(-1) h(-1)) was in the form of NH3 + NH4+. Such ureotelism is typical of terrestrial amphibians like D. mexicanus. Osmotic water flux averaged 0.0193 ml g(-1) x h(-1) in control (sham injected) animals and was not significantly altered by injection of either arginine vasotocin or mesotocin. This osmotic flux is similar to osmotic fluxes found for other terrestrial amphibians. The combined data suggest that metabolism in D. mexicanus is, like most other Gymnophionans, lower than other amphibians. The high rates of nitrogen (especially urea) excretion suggests that this fossorial animal accumulates urea like other burrowing amphibians.
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PMID:Exchanges of oxygen, carbon dioxide, nitrogen and water in the caecilian Dermophis mexicanus. 1112 40


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