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Biomedical subjects

I Macdonald

Publications and source records attributed to I Macdonald.

At least 55 records · Page 3Linked to original sources
PubMed1994

Effect of noradrenaline on glycerol turnover and lipolysis in the whole body and subcutaneous adipose tissue in humans in vivo.

1. The effect of infusion of noradrenaline (0.42 mumol min-1 kg-1) on the exchange of nonesterified fatty acids, glycerol and other metabolites across subcutaneous abdominal adipose tissue was investigated in five healthy subjects using an arteriovenous catheterization technique and measurement of adipose tissue blood flow using the 133Xe clearance technique. At the same time, the net rate of fat oxidation in the whole body was assessed by indirect calorimetry, and the turnover of glycerol in the whole body and in subcutaneous adipose tissue was estimated using [5-2H]glycerol, which was administered as a primed constant infusion for 1 h before (basal turnover) noradrenaline administration and continued during the 1 h of noradrenaline infusion. 2. The noradrenaline infusion increased the plasma noradrenaline concentration from a basal value of 0.9 +/- 0.1 to 12.6 +/- 1.2 nmol/(mean +/- SEM) at 60 min. It also increased the arterialized concentration of glycerol by 50% (basal value 81 +/- 11 mumol/l-1) and that of plasma non-esterified fatty acids three-fold (basal value 357 +/- 86 mumol/l). 3. Noradrenaline increased the net release of glycerol by adipose tissue three-fold and that of non-esterified fatty acids three- to four-fold. Although the ratio of non-esterified fatty acid to glycerol release by adipose tissue increased in all subjects from a mean value of 2.7 in the basal period to 3.6 and 3.9 at 50 and 60 min of the noradrenaline infusion, respectively (P < 0.02), at no time point did the ratio differ significantly from 3.0.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid-Base Equilibrium↗
PubMed1993

Plasma soluble interleukin 2 receptor levels in patients with malignant lymphoma are correlated with disease activity but not cellular immunosuppression.

Studies of peripheral blood lymphocytes (PBL) and plasma from patients with malignant lymphoma [Hodgkin's disease (HD) and non Hodgkin's lymphoma (NHL)] show that plasma soluble interleukin 2 receptor (sIL2R) levels are closely linked with disease status [normal volunteers (n = 15) 402 +/- 158 u/ml; patients with Hodgkin's disease in remission (n = 4) 525 +/- 195 u/ml or with active disease (n = 11) 3026 +/- 1602 u/ml (p < 0.001); patients with non Hodgkin's lymphoma in remission (n = 6) 462 +/- 202 u/ml, active disease (n = 15) 2713 +/- 1755 u/ml, (p < 0.001)] but no correlation between sIL2R and the inhibition of interleukin 2 (IL2) generated cytotoxicity for the cell line K562. In only 1 of 15 patient plasma samples studied was there a dose dependent inhibition of IL2 generated cell killing. In a further patient, IL2 generated K562 killing was inhibited at all doses (500-3000 brmp units/ml); treatment of this plasma with anti-Interleukin 4 (alpha IL4) had no effect on the potent inhibitory activity of the plasma. Plasma sIL2R levels were markedly elevated in patients receiving IL2 in vivo (pre treatment 520 +/- 170 IU/ml, during treatment 5578 +/- 2564 IU/ml, p = 0.05). The aetiology of immunosuppression in patients with lymphoma appears to be multi-factorial; although sIL2R correlates with disease activity it does not appear to directly mediate immunosuppression in most patients with malignant lymphoma.

Cells, Cultured↗
PubMed1992

Studies on the immediate and delayed leucocytosis elicited by brief (30-min) strenuous exercise.

Eight healthy male volunteers exercised for two 30-min sessions starting 3 h apart on an electronically braked cycle ergometer at a work load (mean 155.9 W, SD 33.4 W) which required an oxygen consumption that was 70% of their maximal rate of oxygen uptake. Venous blood samples were taken through an indwelling cannula over a period of 6 h beginning shortly before the first bout of exercise and were analysed for routine haematological parameters and for lactate, noradrenaline, adrenaline and cortisol. Both bouts of exercise induced an immediate leucocytosis due to rises in lymphocytes and neutrophils but only the first exercise bout induced a substantial delayed neutrophilia. In at least five subjects, changes in lymphocyte and platelet numbers were correlated (Spearman's rank procedure, P less than 0.05) with simultaneous changes in the plasma concentrations of lactate, noradrenaline and adrenaline over the 6-h period studied. Increases in the plasma concentration of cortisol due to exercise correlated positively with the percentage changes in neutrophil numbers at 3 h and 6 h. These results are consistent with the suggestion that the immediate and delayed leucocytosis induced by exercise are mediated respectively by catecholamine and by cortisol.

Adult↗
PubMed1992

Food and drink in sport.

The nutrition and fluid requirements of a sportsperson should be tailored not only to the sport, with endurance being the most important variable, but also to the individual competitor and the physical environment at the time of the event. This applies especially to fluid intake. There is agreement that the proportion of carbohydrate in the diet should be high and that of fat low. The evidence for increased metabolic demands for vitamins and minerals (except possibly calcium and iron) in exercise is equivocal. Fluid is still the priority constituent that needs monitoring.

Diet↗
PubMed1992

Poor prognosis acute myeloid leukaemia treated by matched unrelated donor marrow transplant without preceding total body irradiation.

Two patients with acute myeloid leukaemia, one in relapse after autologous bone marrow transplantation (BMT) (aged 52 years) and the other with primary resistant disease secondary to previously treated malignancy, have received marrow transplants from matched unrelated donors. Cytoreductive conditioning in both cases was with high-dose combination chemotherapy alone. Engraftment was aided by the administration of total lymphoid irradiation together with in vivo antilymphocyte antibody prior to marrow infusion. Both patients survive in complete remission, currently at 12 and 15 months post-BMT respectively. The avoidance of total body irradiation in BMT patients at high risk of early treatment-related mortality may be advantageous.

Adult↗
PubMed1991

Brief exercise induces an immediate and a delayed leucocytosis.

Haematological profiles were measured: (1) before and for 5 h 30 min after 30 min sports (squash, swimming, jogging); and (2) before, during and for 2 h 30 min after 30 min cycle ergometry at workloads which required rates of oxygen consumption that were between 48% and 84% of maximal. In both instances exercise induced an immediate leucocytosis (owing to rises in both neutrophils and lymphocytes) which subsided rapidly at the finish of exercise and was followed by a delayed neutrophilia of greater magnitude which peaked at approximately 3 h after the start of exercise. Changes in plasma catecholamines and cortisol recorded during and after exercise (cycle ergometry only) support the hypothesis that the immediate leucocytosis during brief exercise is attributable to elevated catecholamine levels, whereas the delayed neutrophilia is due to raised cortisol levels.

Adult↗
PubMed1990

Beta-adrenoceptor blockade and CNS-related subjective symptoms: a randomized, double-blind, placebo-controlled comparison of metoprolol CR/ZOK, atenolol and propranolol LA in healthy subjects.

The effect of once daily treatment with atenolol (100 mg), metoprolol CR/ZOK (100 mg) and propranolol LA (160 mg) for one week on CNS-related subjective symptoms was compared with that of placebo using a randomised, double-blind cross-over design in 12 healthy volunteers. The symptoms were recorded using a previously documented self-administered questionnaire (MSE-profile), which included three dimensions: Contentment, Vitality and Sleep. Compared to placebo, all three beta-adrenoceptor antagonists reduced the exercise heart rate at 24 hours but a somewhat more pronounced effect was found with propranolol LA. No significant difference in any of the dimensions was detected between placebo and either metoprolol CR/ZOK or atenolol tablets. Following propranolol LA treatment a deterioration in the dimensions Vitality and Sleep was observed compared with both placebo and the beta 1-selective drugs. Difference in lipophilicity between the beta 1-selective agents metoprolol and atenolol has little bearing on the occurrence of the CNS-related symptoms, in comparison to the marked effects of the lipophilic and nonselective compound propranolol.

Adrenergic beta-Antagonists↗
PubMed1990

Effects of a week's beta-adrenoceptor blockade with atenolol and metoprolol CR/ZOK on the response to exercise in healthy women aged 50 to 70 years.

12 healthy women with a mean age of 60 years (range 50-70 years) were treated with 50 mg atenolol or 100 mg metoprolol CR/ZOK or placebo for 1 week in a double-blind, randomized, cross-over study. Laboratory measurements of the cardiovascular responses to exercise were made 2-4 hours after and again 24 hours after the last tablet. Blood pressure and heart rate at rest were reduced equally by the two beta-adrenoceptor antagonists. The reductions in blood pressure and heart rate during graded exercise and then during prolonged steady treadmill exercise 3-4 hours after the tablet were greater for atenolol than metoprolol CR/ZOK. The reductions in cardiac output showed a similar pattern. Lactate concentrations and ratings of perceived exertion tended to be highest on metoprolol CR/ZOK, but these differences were inconsistent. We conclude that despite the changes in the cardiovascular system in these 50-70 year-old women, exercise tolerance was not greatly affected by beta-adrenoceptor blockade.

Aged↗
PubMed1990

Sugars for success?

Explore the source record for details and available documents.

Dietary Carbohydrates↗
PubMed1989

Some effects of various dietary carbohydrates on thyroid activity in the rat.

Four groups of 6 rats were given ad libitum diets with over 60% of the energy as sucrose, fructose or glucose for 10 weeks, and were compared to animals given chow. Assessment of thyroid activity was made using metabolic rate, thyroid 123I uptake, and serum thyroid fraction measurement before, after 5 and 10 weeks on the diet, and 6 weeks after return to a control diet. The major effects were that the thyroid 123I uptake was significantly less than control in the rats after 10 weeks on a high carbohydrate diet. Only the animals on the fructose diet showed any consistent and significant falls in serum T3 and FT3, and T4. These findings suggest that the type of dietary carbohydrate may affect thyroid function in rats.

Animals↗
PubMed1988

Effects of ingesting glucose and some of its polymers on serum glucose and insulin levels in men and women.

Twelve men and 10 women were given maltodextrin (DE20) at various dose levels after an overnight fast. Similar studies were carried out with glucose, maltose and another maltodextrin (DE5). It was found that within each sex the serum glucose and insulin responses were not influenced by the physical form of glucose ingested over a 90-min period. However, the serum glucose response to glucose and to its polymers was found to be dose-dependent in the men but not in the women. The serum insulin response was dose-dependent in both sexes. At any glucose dose level the serum insulin response was approximately 40% greater in men compared to women.

Blood Glucose↗
PubMed1987

Effect of cimetidine on prognosis after simple closure of perforated duodenal ulcer.

A prospective controlled study in 60 patients undergoing simple closure of perforated duodenal ulcer demonstrated a significant (P less than 0.05) benefit following postoperative cimetidine treatment, in terms of avoiding subsequent dyspeptic symptoms and complications of peptic ulcer disease. Thus cimetidine is recommended in the follow-up management of perforated duodenal ulcers.

Aged↗