The influence of diet and exercise on muscle and plasma glutamine concentrations

Purpose: This study examined the relationship between muscle glutamine, muscle glycogen, and plasma glutamine concentrations over 3 d of high-intensity exercise during which dietary carbohydrate (CHO) intake varied. Methods: Five endurance-trained men completed two exercise trials in randomized order, over a 14-d period. Each trial required subjects to perform 50 min of high-intensity continuous and interval exercise on three consecutive days while consuming a diet that provided 45% of the energy as CHO or a diet in which CHO provided 70% of the total energy. Four days of inactivity and consumption of a 55% CHO diet separated the two randomized trials. Menus and food were provided for the subjects and all food and drink consumed were weighed and recorded for later analysis. Before exercise on the first day of each trial, at the start of exercise on day 3 and on completion of exercise on day 3, muscle was biopsied from the vastus lateralis for the analysis of glutamine and glycogen concentrations. Venous blood was sampled before and twice after exercise on each day for the analysis of plasma glutamine and cortisol concentrations. Results: Mean plasma glutamine concentration was significantly higher during the 70% CHO exercise trial when compared with the 45% CHO trial (P < 0.05). Glycogen decreased by the same magnitude during both trials and there was no relationship between changes in plasma glutamine and changes in muscle glycogen concentration. Muscle glutamine concentration did not change in either trial. Conclusions: These data suggest that the influence of carbohydrate intake upon the concentration of plasma glutamine is not mediated through the concentration of intramuscular glycogen.

A critical comparison of the external and internal boron requirements for contrasting species in boron-buffered solution culture

Despite reports that boron (B) requirements differ among plant species there is a shortage of critical evidence to demonstrate unequivocally whether species differ in internal or external B requirements or both. The present research was conducted to establish the external and internal B requirements of three contrasting species, a woody dicot (marri), an herbaceous dicot (sunflower) and a monocot (wheat) using B-buffered solution culture. Boron-buffered solution culture provided satisfactory control of external B concentrations ranging from 0.04 to 30 muM throughout the 20- (sunflower and wheat) or 40-day (marri) growth period. At low external B concentrations (less than or equal to 0.13 muM), the growth of marri and sunflower was severely depressed but by contrast the vegetative growth of wheat plants was satisfactory and free of B deficiency symptoms. Marri and sunflower plants achieved total maximum shoot growth at greater than or equal to1.2 muM B in solutions while wheat plants did so at greater than or equal to 0.6 muM B. The critical B concentrations (mg kg(-1) dry matter) in the youngest open leaf blades of marri, sunflower and wheat plants were 17.9, 19.7 and 1.2 on 20, 10 and 10 days after transplanting (DAT), respectively. Lower internal and external B requirements of wheat were matched by a lower uptake rate of B compared to marri and sunflower.

Population pharmacokinetics of tacrolimus in children who receive cut-down or full liver transplants

Background. The aim of this study was to investigate the population pharmacokinetics of tacrolimus in pediatric liver transplant recipients and to identify factors that may explain pharmacokinetic variability. Methods. Data were collected retrospectively from 35 children who received oral immunosuppressant therapy with tacrolimus. Maximum likelihood estimates were sought for the typical values of apparent clearance (CL/F) and apparent volume of distribution (V/F) with the program NONMEM. Factors screened for influence on the pharmacokinetic parameters were weight, age, gender, postoperative day, days since commencing tacrolimus therapy, transplant type (whole child liver or cut-down adult liver), liver function tests (bilirubin, alkaline phosphatase [ALP], aspartate aminotransferase [AST], gamma -glutamyl transferase [GGT], alanine aminotransferase [ALT]), creatinine clearance, hematocrit, corticosteroid dose, and concurrent therapy with metabolic inducers and inhibitors of tacrolimus. Results. No clear correlation existed between tacrolimus dosage and blood concentrations (r(2) =0.003). Transplant type, age, and liver function test values were the most important factors (P

Deletion of 8p: a report of a child with normal intelligence

The case is presented of a female infant with a distal deletion of 8p (8p23.1 --> pter) whose development was monitored over a 5-year period from 12 months of age. Although previous literature has suggested that 8p deletion is associated with mild to moderate intellectual disability, the child reported here has normal intelligence. Despite initial delays in gross motor and language skills, cognitive development (assessed with the Bayley Scales of Infant Development) and intellectual ability (measured on the Stanford-Binet Intelligence Scale) were within average range. It is argued that the small number of previous case reports may have created a misleading impression of intellectual development in individuals with distal deletions of 8p.

Child-Pugh class, nutritional indicators and early liver transplant outcomes

Background/Aims: Patients with chronic liver disease undergoing liver transplantation have reduced body fat and muscle mass. The extent to which nutritional indicators and Child-Pugh class are predictive of postoperative outcome in adults is unclear. The aims of this study were to determine in adult patients undergoing transplant 1) the influence of preoperative Child-Pugh class and nutritional indicators on early transplant outcomes and one-year survival, 2) the relationship between nutritional indicators and Child-Pugh class and disease type. This study included 80 patients (1990-1994). Methodology: The nutritional indicators utilized were grip strength, triceps skinfold thickness and uncorrected mid-arm muscle area. Measured outcomes were ventilator time, intensive care stay, postoperative hospital stay and one-year survival. Results: Early morbidity was determined in survivors. Child-Pugh class C patients required longer ventilation and spent more time in the intensive care unit than Child-Pugh classes A and B. No significant relationships were found length of hospital stay. Relationships between the nutritional indicators (when controlled for Child-Pugh class) and early morbidity could not be determined due;to insufficient data. No relationship was established between one-year survival and Child-Pugh class or the nutritional indicators. Grip strength and mid-arm muscle area were lower in the patients in Child-Pugh:classes B and C. Parenchymal liver disease was associated with lower grip strength and mid-arm muscle area when compared to cholestatic disease. Conclusions: Child-Pugh class C is associated with greater early postoperative morbidity. Advanced Child-Pugh class is also associated with diminished muscle status and parenchymal disease.

Energy cost of physical activity in cystic fibrosis

Objective: The purpose of this study was to compare the energy cost of standardized physical activity (ECA) between patients with cystic fibrosis (CF) and healthy control subjects. Design: Cross-sectional study using patients with CF and volunteers from the community. Setting: University laboratory. Subjects: Fifteen patients (age 24.6 +/- 4.6 y) recruited with consent from their treating physician and 16 healthy control subjects (age 25.3 +/- 3.2) recruited via local advertisement. Interventions. Patients and controls walked on a computerised treadmill at 1.5 km/h for 60 min followed by a 60 min recovery period and, on a second occasion, cycled at 0.5 kp (kilopond), 30 rpm followed by a 60 min recovery. The ECA was measured via indirect calorimetry. Resting energy expenditure (REE), nutritional status, pulmonary function and genotype were determined. Results: The REE in patients was significantly greater than the REE measured in controls (P = 0.03) and was not related to the severity of lung disease or genotype. There was a significant difference between groups when comparing the ECA for walking kg root FFM (P = 0.001) and cycling kg root FFM (P = 0.04). The ECA for each activity was adjusted (ECA(adj)) for the contribution of REE (ECA kJ kg root FFM 120 min(-1) - REE kJ kg root FFM 120 min(-1)). ECA(adj) revealed a significant difference between groups for the walking protocol (P = 0.001) but no difference for the cycling protocol (P = 0.45). This finding may be related to the fact that the work rate during walking was more highly regulated than during cycling. Conclusions ECA in CF is increased and is likely to be explained by an additional energy-requiring component related to the exercise itself and not an increased REE. Sponsorship. The Prince Charles Hospital Foundation; MLR was in receipt of a QUTPRA Scholarship.