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Biomedical subjects

M Gleeson

Publications and source records attributed to M Gleeson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Delayed-onset muscle damage and lipid peroxidation in man after a downhill run.

Lipid peroxidation initiated by free radical reactions is associated with tissue necrosis in a variety of conditions. We have measured serum lipid peroxide concentrations (as total thiobarbituric acid-reactive substances, TBARS) and creatine kinase (CK), lactate dehydrogenase (LDH), and aspartate aminotransferase (AST) activities and subjective muscle soreness in 16 men before and after a 45-minute downhill treadmill run. TBARS concentrations and enzyme activities were increased after exercise, with peak values observed at 6 hours (TBARS, LDH) or 24 hours (CK, AST) after exercise. Serum LDH activity returned to preexercise levels by 48 hours after exercise and TBARS by 72 hours after exercise: CK and AST activities remained elevated 72 hours after exercise. Leg muscle soreness also increased, with the greatest degree of soreness seen at 24 or 48 hours after exercise. Subjects with the greatest increase in CK, LDH, and AST also showed the highest serum TBARS concentration. This suggests a possible relationship between free radical generation and exercise-induced muscle damage.

Adult↗
PubMed1989

Results of middle ear ventilation with Goode's tubes.

The results of a retrospective study of the effect and outcome of middle ear ventilation by Goode's tubes are presented. 83 ears from 50 patients were analyzed both as a group and in age-related sub-groups over a mean follow-up period of 1.83 years. The mean period of ventilation by Goode's tubes before removal or extrusion was 18.4 months. The tubes became infected in 70.4% and were spontaneously extruded in 44.9% of patients. Permanent perforation of the tympanic membrane ensued in 47.5% of patients and significantly more often in those aged between 10 and 20 years (P less than 0.002). Patients aged less than 10 years were significantly less likely to develop a retraction of their tympanic membranes after removal of the Goode's tube than those older (P less than 0.02). No significant relationship was found between the development of these complications and the period of ventilation, past experience of otitis media, consistency of effusion, degree of tympanosclerosis or the preoperative presence of tympanic retraction.

Adolescent↗
PubMed1989

Molecular characteristics of IgA in infant saliva.

Saliva was collected from 57 infants aged 6 weeks to 2.5 years and the molecular form of IgA was studied by centrifugation on sucrose density gradients. Two distinct populations were identified. Seventy-two per cent of the children had secretory IgA in their salivary secretions, while 28% had a molecular form corresponding to monomeric IgA. No samples with concurrent monomeric and secretory forms were detected. Monomeric IgA was not detected in any infant over 12 months of age. Secretory component was detected in all samples but was not associated with monomeric IgA. Forty-seven per cent of the samples contained IgA fragments of approximately 40,600 molecular weight. The presence of fragments dominated in the group of children with monomeric IgA. The presence of monomeric IgA in infant saliva did not result from degradation due to storage or proteolysis. The study demonstrated an apparent maturation sequence in the molecular form of IgA present in the salivary secretions of infants.

Adult↗
PubMed1989

Audit of investigation and follow-up of patients with raised monoclonal proteins.

OBJECTIVE: To assess the adequacy of investigation and later review of patients with serum monoclonal proteins detected in our laboratory. METHOD: To review all monoclonal proteins detected and to search through the laboratory computerized records for evidence of further investigation and later review. RESULTS: Nine per cent of monoclonal proteins detected were not followed up at all. A urine examination to detect Bence-Jones protein was not requested in 12% of those regularly followed up. The mean age of the patients studied was 69 years, but there were eight patients under 60 years who had multiple myeloma.

Aged↗
PubMed1988

The effects of diet on muscle pH and metabolism during high intensity exercise.

Five healthy male subjects exercised for 3 min at a workload equivalent to 100% VO2max on two separate occasions. Each exercise test was performed on an electrically braked cycle ergometer after a four-day period of dietary manipulation. During each of these periods subjects consumed either a low carbohydrate (3 +/- 0%, mean +/- SD), high fat (73 +/- 2%), high protein (24 +/- 3%) diet (FP) or a high carbohydrate (82 +/- 1%), low fat (8 +/- 1%) low protein (10 +/- 1%) diet (CHO). The diets were isoenergetic and were assigned in a randomised manner. Muscle biopsy samples (Vastus lateralis) were taken at rest prior to dietary manipulation, immediately prior to exercise and immediately post-exercise for measurement of pH, glycogen, glucose 6-phosphate, fructose 1,6-diphosphate, triose phosphates, lactate and glutamine content. Blood acid-base status and selected metabolites were measured in arterialised venous samples at rest prior to dietary manipulation, immediately prior to exercise and at pre-determined intervals during the post-exercise period. There was no differences between the two treatments in blood acid-base status at rest prior to dietary manipulation; immediately prior to exercise plasma pH (p less than 0.01), blood PCO2 (p less than 0.01), plasma bicarbonate (p less than 0.001) and blood base-excess (p less than 0.001) values were all lower on the FP treatment. There were no major differences in blood acid-base variables between the two diets during the post-exercise period.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1988

Influence of a 36 h fast followed by refeeding with glucose, glycerol or placebo on metabolism and performance during prolonged exercise in man.

Five men were studied during exercise to exhaustion on an electrically braked cycle ergometer at 70% of VO2max. The four experimental treatments were as follows: fasted for 36 h (A); fasted (36 h) and refed with glucose (B) or glycerol (C); postabsorptive (overnight fast, D). In B and C the subjects were given a drink containing glucose or glycerol (1g per kg body weight) 45 min before starting exercise. A placebo drink was given 45 min before exercise on treatments A and D. Despite an increased availability of circulating free fatty acids, beta-hydroxybutyrate and glycerol exercise time to exhaustion was significantly lower after fasting (treatment A 77.7 +/- 6.8 min) compared with treatment D (119.5 +/- 5.8 min). Refeeding with glucose or glycerol did not significantly improve performance (92.4 +/- 11.8 min and 80.8 +/- 3.6 min respectively) compared with treatment A and lowered circulating levels of FFA and beta-HB during exercise compared with A. Despite the probability of low liver glycogen levels after fasting, none of the subjects became hypoglycaemic (blood glucose less than 4 mmol.l-1) during exercise and their blood lactate concentrations were not high at exhaustion. Plasma levels of branched chain amino acids (BCAA) decreased progressively during exercise on treatments A, B and C and were considerably lower at exhaustion compared with treatment D. Falling plasma concentrations of BCAA during prolonged exercise may be implicated in the generation of central fatigue.

3-Hydroxybutyric Acid↗
PubMed1988

Diet-induced metabolic acidosis and the performance of high intensity exercise in man.

The influence of four isolated periods of dietary manipulation upon high intensity exercise capacity was investigated in six healthy male subjects. Subjects consumed their 'normal' (N) diet (45 +/- 2% carbohydrate (CHO), 41 +/- 3% fat, 14 +/- 3% protein) for four days after which they exercised to voluntary exhaustion at a workload equivalent to 100% VO2max. Three further four-day periods of dietary manipulation took place; these were assigned in a randomised manner and each was followed by a high intensity exercise test. The dietary treatments were: a low CHO (3 +/- 1%), high fat (71 +/- 5%), high protein (26 +/- 3%) diet (HFHP); a high CHO (73 +/- 2%), low fat (12 +/- 2%), normal protein (15 +/- 1%) diet (HCLF); and a normal CHO (47 +/- 3%), low fat (27 +/- 2%), high protein (26 +/- 2%) diet (LFHP). Acid-base status and blood lactate concentration were measured on arterialised-venous blood at rest prior to dietary manipulation on each day of the different diets, immediately prior to exercise and at 2, 4, 6, 10 and 15 min post-exercise. Other metabolite concentrations were measured in the blood samples obtained prior to dietary manipulation and immediately prior to exercise. Exercise time to exhaustion after the HFHP diet (179 +/- 63 s) was shorter when compared with the N (210 +/- 65 s; p less than 0.01) and HCLF (219 +/- 69 s; p less than 0.05) diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1988

The effects of a glycogen loading regimen on acid-base status and blood lactate concentration before and after a fixed period of high intensity exercise in man.

Six healthy male subjects exercised after an overnight fast for a fixed 3 min period at a workload equivalent to 100% of their maximal oxygen uptake (VO2max) on 3 separate occasions. The first test took place after subjects had consumed a mixed diet (43 +/- 3% carbohydrate (CHO), 41 +/- 5% fat and 16 +/- 3% protein) for 3 days, and was followed 2 h later by prolonged cycling to exhaustion at 77 +/- 3% VO2max to deplete muscle glycogen stores. Following this, subjects consumed a low CHO diet (4 +/- 1% CHO, 63 +/- 5% fat and 33 +/- 6% protein) for the remainder of the day and for the subsequent 2 days; on the morning of the next day a second high intensity test took place. Finally subjects followed a 3 day high CHO diet (73 +/- 7% CHO, 17 +/- 6% fat and 10 +/- 1% protein) before their last test. Acid-base status and selected metabolites were measured on arterialized-venous blood at rest prior to exercise and at intervals for 15 min following exercise. Prior to exercise, plasma pH and blood lactate concentration were higher (p less than 0.05) after the high CHO diet when compared with the low CHO diet. Pre-exercise plasma bicarbonate, blood PCO2 and blood base excess were all higher after the high (p less than 0.001, p less than 0.01, p less than 0.01 respectively) and normal (p less than 0.05, p less than 0.05, p less than 0.05 respectively) CHO diets when compared with the low CHO diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1988

Influence of a 24 h fast on high intensity cycle exercise performance in man.

The influence of a 24 h fast on endurance performance and the metabolic response to maximal cycle exercise was investigated in 6 healthy men (mean +/- SD: age = 27 +/- 7 years; weight = 73 +/- 10 kg; VO2max = 46 +/- 10 ml.kg-1.min-1). Subjects performed in randomised order two exercise bouts to exhaustion separated by one week. Test rides were performed in fasted (F) and post-absorptive (normal-diet, ND) conditions on an electrically braked cycle ergometer at a workload equivalent to 100% of VO2max. Acid-base status and selected metabolites were measured on arterialised venous blood at rest prior to exercise and at intervals for 15 mins following exercise. Exercise time to exhaustion was shorter after F compared with ND (p less than 0.01). Pre-exercise blood bicarbonate (HCO3-) concentration, PCO2 and base excess (BE) were lower after F compared with ND (p less than 0.05). Prior to exercise, circulating concentrations of free fatty acids (FFA), beta-hydroxybutyrate (B-HB) and glycerol were higher after F compared with ND (p less than 0.01) but blood glucose and lactate concentration were not different. On the F treatment, after exercise, blood pH, HCO3-, and BE were all significantly higher (p less than 0.01) than on ND; blood lactate concentration was significantly lower for the whole of the post-exercise period after F compared with ND (p less than 0.01). Circulating levels of FFA and B-HB after exercise on the F treatment fell but levels of these substrates were not altered by exercise after ND.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1987

A simple enzymatic fluorimetric method for the determination of branched-chain L-amino acids in microlitre volumes of plasma.

Existing methods for the estimation of the branched-chain amino acids (BCAA) normally require sophisticated, expensive instrumentation. An alternative is an enzymatic spectrophotometric method but this requires relatively large volumes of blood and is rather time-consuming. A simple enzymatic fluorimetric method for the measurement of the BCAA in microliter samples of plasma is described here. The method is based on the oxidative deamination of L-leucine, L-isoleucine and L-valine by leucine dehydrogenase from Bacillus species. The NADH which is formed in stoichiometric quantities is estimated fluorimetrically. In the presence of the ketone-trapping agent hydrazine the reaction goes to completion in an alkaline incubation medium at 37 degrees C. By this method the combined BCAA can be measured routinely in 20 microliter sample of plasma. The test exhibits acceptable precision and reproducibility.

Adult↗
PubMed1987

Dietary composition and acid-base status: limiting factors in the performance of maximal exercise in man?

Seven healthy male subjects exercised to exhaustion at a workload equivalent to 100% of their maximal oxygen uptake (VO2max) on 3 separate occasions. Each high intensity exercise test was performed on an electrically braked cycle ergometer; the first took place after a normal diet (46 +/- 8% carbohydrate (CHO), 41 +/- 7% fat and 13 +/- 3% protein); the second after 3 days of a low CHO diet (7 +/- 3% CHO, 64 +/- 5% fat and 29 +/- 4% protein) and the third after 3 days of a high CHO diet (76 +/- 6% CHO, 14 +/- 5% fat and 10 +/- 2% protein). Acid-base status and selected metabolites were measured on arterialized venous blood at rest prior to exercise and during the post-exercise period. Plasma urea concentration and urine total acidity were measured on each day of the experiment. Exercise time to exhaustion was longer after the normal (p less than 0.05) and high (p less than 0.01) CHO diets compared with the low CHO diet. Pre-exercise plasma bicarbonate concentration and blood PCO2 were higher after the high CHO diet when compared with the normal (p = 0.05, p less than 0.05 respectively) and low CHO conditions (p less than 0.05, p less than 0.05 respectively). Pre-exercise bicarbonate was also higher after the normal CHO diet when compared with the low CHO diet (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1987

The effect of dietary carbohydrate intake on the metabolic response to prolonged walking on consecutive days.

Six healthy subjects walked 37 km per day for four consecutive days on two occasions one month apart; on one walk, subjects consumed a high carbohydrate (CHO) diet (85 +/- 1% CHO, Mean +/- SE) and on the other walk an isocaloric low CHO diet (2 +/- 0% CHO) was consumed. Subjects were fasted each day until after the completion of the walk. Blood samples were obtained at rest prior to exercise and after completion of each of three laps of 12.3 km. Exercise intensity corresponded to approximately 17% of VO2max. The first day of each walk demonstrated that the pattern of substrate mobilisation in response to this type of exercise is highly reproducible, there being no difference in any of the parameters measured between the two walks. Circulating glucose, lactate, insulin and triglyceride levels remained essentially unchanged; alanine fell progressively and glycerol, free fatty acid (FFA) and 3-hydroxybutyrate (BHB) rose progressively. After the first day there was a general tendency for the blood glucose concentration to decline as exercise progressed; by the end of the walk on Day 2, blood glucose was lower on the low CHO diet than on the high CHO diet. On Day 4 plasma insulin was higher (p less than 0.05) on the high CHO diet than on the low CHO diet and declined progressively on both diets. Blood lactate and alanine concentrations were generally higher at rest on the high CHO diet, but fell so that no differences existed by the end of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

The effects of dietary manipulation on blood acid-base status and the performance of high intensity exercise.

The effect of a pattern of exercise and dietary modification, which is normally used to alter muscle glycogen content, upon the acid-base status of the blood and the ability to perform high intensity exercise was studied. Eleven healthy male subjects cycled to exhaustion on an electrically braked cycle ergometer at a workload equivalent to 100% of their maximal oxygen uptake (VO2max) on three separate occasions. The first exercise test took place after a normal diet (46.2 +/- 6.7% carbohydrate (CHO)), and was followed by prolonged exercise to exhaustion to deplete muscle glycogen stores. The second test was performed after three days of a low carbohydrate diet (10.1 +/- 6.8% CHO) and subsequently after three days of a high CHO diet (65.5 +/- 9.8% CHO) the final test took place. Acid-base status and selected metabolites were measured on arterialised venous blood at rest prior to exercise and during the post-exercise period. Exercise time to exhaustion was longer after the normal (p less than 0.05) and high (p less than 0.05). CHO dietary phases compared with the low CHO phase. Resting pre-exercise pH was higher after the high CHO diet (p less than 0.05) compared with the low CHO diet. Pre-exercise bicarbonate, PCO2 and base excess measurements were higher after the high CHO treatment compared with both the normal (p less than 0.01, p less than 0.05, p less than 0.01 respectively) and low CHO phases (p less than 0.001, p less than 0.01, p less than 0.001 respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1987

Metabolic and circulatory responses to the ingestion of glucose polymer and glucose/electrolyte solutions during exercise in man.

Six men exercised on a cycle ergometer for 60 min on two occasions one week apart, at 68 +/- 3% of VO2max. On one occasion, a dilute glucose/electrolyte solution (E: osmolality 310 mosmol X kg-1, glucose content 200 mmol X l-1) was given orally at a rate of 100 ml every 10 min, beginning immediately prior to exercise. On the other occasion, a glucose polymer solution (P: osmolality 630 mosmol X kg-1, glucose content equivalent to 916 mmol X l-1) was given at the same rate. Blood samples were obtained from a superficial forearm vein immediately prior to exercise and at 15-min intervals during exercise; further samples were obtained at 15-min intervals for 60 min at rest following exercise. Heart rate and rectal temperature were measured at 5-min intervals during exercise. Blood glucose concentration was not different between the two tests during exercise, but rose to a peak of 8.7 +/- 1.2 mmol X l-1 (mean +/- SD) at 30-min post-exercise when P was drunk. Blood glucose remained unchanged during and after exercise when E was drunk. Plasma insulin levels were unchanged during exercise and were the same on both trials, but again a sharp rise in plasma insulin concentration was seen after exercise when P was drunk. The rate of carbohydrate oxidation during exercise, as calculated from VO2 and the respiratory exchange ratio, was not different between the two tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Adenine nucleotides in erythrocytes from patients with peripheral vascular disease and the effects of oxpentifylline.

The relationship between erythrocyte nucleotide profiles and the presence of atherosclerotic peripheral occlusive vascular disease was investigated. In elderly male patients with severe vascular insufficiency the mean red cell content of NAD, GDP, GTP, AMP, ADP and ATP and the cellular adenylate energy charge were not significantly different from those observed in young healthy males. It has been claimed that drugs such as oxpentifylline improve peripheral tissue oxygenation in vascular disease by reversing the fall in red cell ATP content which has been reported to accompany vascular insufficiency resulting in a restoration of normal cell deformability and hence whole blood viscosity. We have carried out in vitro studies using erythrocytes from normal adults to assess the effect of oxpentifylline on erythrocyte ATP content and glycolytic rate. The drug failed to significantly affect the rates of glucose consumption and lactate production or the ATP content of the erythrocytes compared with controls. Furthermore the drug did not influence the rate of ATP utilisation by erythrocytes. We conclude that red cell ATP and total adenylate content is not different from normal in patients with peripheral vascular disease. If oxpentifylline alters red cell deformability it does so by some mechanism not related to the cellular ATP concentration, the cellular adenylate energy charge or the glycolytic rate.

Adenine Nucleotides↗
PubMed1987

Influence of exercise on ascorbic acid status in man.

1. The response of circulating leucocytes with regard to changes in number, proportion of granulocytes and lymphocytes, as well as changes in the ascorbic acid (AA) concentration of plasma and isolated lymphocytes, were studied in nine men who ran a 21 km race. A marked leucocytosis was noted 5 min after the race, the predominant increase being in granulocytes (P less than 0.001) with smaller relative increases in circulating lymphocytes (P less than 0.01) and platelets (P less than 0.001). Numbers of leucocytes and platelets returned to pre-exercise levels within 24 h after the race. 2. The concentration of AA in plasma increased from 52.7 +/- 4.1 mumol/l before the race to 67.0 +/- 5.3 mumol/l within 5 min after the race (P less than 0.001). This increase in plasma AA concentration was positively correlated with the rise in plasma cortisol concentration during the race (r = 0.89; P less than 0.01). However, within 24 h after the race the plasma concentration of AA fell 20 +/- 4% below pre-exercise values (P less than 0.01) and remained low for at least the next 2 days (P less than 0.05). 3. Lymphocyte AA concentration increased from 15.6 +/- 0.6 to 19.7 +/- 0.9 mumol/g of lymphocyte protein during the race (P less than 0.01) but returned to normal levels within 2 days after the race. 4. It is suggested that the adrenal gland may be the major source of AA efflux into the circulation during exercise.

Adult↗