Search PubMed⌕ Search

Biomedical subjects

D B Morgan

Publications and source records attributed to D B Morgan.

At least 55 records · Page 3Linked to original sources
PubMed1982

Effect of fasting on the disappearance of injected alanine and 3-hydroxybutyrate in obese subjects.

1. The blood concentrations of 3-hydroxybutyrate and alanine were measured before and after they were separately injected into obese patients who were taking a 1.68 MJ (400 kcal) diet and again when they had starved for 4 days and 28 days. 2. The disappearance of the injected metabolite was exponential and its half-life and volume of distribution were calculated. 3. The disappearance of ketones (both 3-hydroxybutyrate and acetoacetate) was raised in the patients when they were taking the low-calorie diet and increased a further sevenfold during starvation. This further increase was associated with an increase in the half-life of injected 3-hydroxybutyrate. 4. The pre-injection concentration of alanine almost halved during starvation and the half-life of injected alanine increased. 5. If the changes in half-life of exogenous 3-hydroxybutyrate and alanine apply to endogenous metabolites, then these results suggest that the increase in blood ketone concentration during starvation is at least partly due to a decreased clearance of ketones and the decrease in blood alanine concentrations is associated with a marked decrease in production rate of alanine.

3-Hydroxybutyric Acid↗
PubMed1982

The relation between membrane cholesterol and phospholipid and sodium efflux in erythrocytes from healthy subjects and patients with chronic cholestasis.

1. The cholesterol and phospholipid content of the cell membrane and the efflux of sodium were measured in the erythrocytes of patients with chronic cholestasis and in healthy subjects. 2. The membranes from the patients contained more cholesterol and phospholipid and had a higher cholesterol/phospholipid molar ratio than the membranes from the healthy subjects. 3. The sodium efflux rate constant was reduced in the patients and this was entirely due to a reduction in the frusemide-sensitive efflux rate constant. There was no difference in either the ouabain-sensitive or the ouabain plus frusemide-resistant rate constants. 4. This reduction in the frusemide-sensitive rate constant was associated with a reduction in the erythrocyte sodium content. 5. When erythrocytes were loaded with cholesterol in vitro the frusemide-sensitive efflux rate constant was reduced by an amount similar to that observed in the patients. In addition, however, there was a reduction in the ouabain-sensitive efflux rate constant and an increase in the erythrocyte sodium content; neither of these changes was observed in the patients in vivo.

Adult↗
PubMed1982

Acidosis and severe megaloblastic anaemia.

Ten patients with severe megaloblastic anaemia were studied to investigate whether the causative metabolic defects might predispose them to lactic or other acidosis. One patient had compensated acidosis with hyperlactataemia before treatment but there were obvious causes other than anaemia. No other patient developed an acidosis. Neither anaemia per se nor the metabolic defects of vitamin B(12) or folic acid deficiency are likely to cause clinically significant lactic acidosis or hyperlactataemia.

Acidosis↗
PubMed1982

The body composition of the chronic mentally ill.

The height and weight were measured and the total fat and fat-free mass were estimated in 1123 patients in a mental hospital. The results were compared with the reported values in healthy persons. The young patients weighed the same as young healthy persons whereas the average weight in the elderly patients was much less than healthy elderly persons. In the elderly women patients, this difference in weight was much greater in those with dementia than in those with affective disorders or schizophrenia. The difference in weight was not related to the duration of stay in hospital, and there was no evidence that it was due to malnutrition. The lower weight may therefore by a marker for those persons likely to need institutional care rather than the result of loss of weight. A minority of the elderly patients, particularly the ill and immobile, had one of the biochemical markers of malnutrition, low plasma concentrations of either albumin or vitamin C or vitamin D. On average, these patients weighed less and had less body fat than the others. These patients may be the high-risk group for nutritional deficiency but there was no evidence that any of them had a clinically significant nutritional problem.

Adipose Tissue↗
PubMed1981

The evaluation of a new enzyme immunoassay for the measurement of prostatic acid phosphatase.

An enzyme immunoassay for prostatic acid phosphatase (PAP) has been assessed. An upper limit normal is set at 1.8 microgram/1. There is a very low incidence of raised levels in chronic diseases or cancers other than those of the prostate. Patients with well-controlled prostatic cancer have levels less than 1.8 microgram/1 and show little variation about their own mean. PAP can rise exponentially with a doubling time of 1-5 months. This assay is unlikely to increase the detection of asymptomatic prostatic cancer as 66% of T0-2NXM0 cases had PAP less than 1.8 microgram/1. The main advantages over routine enzyme assays are its sensitivity and accuracy in the lower range.

Acid Phosphatase↗
PubMed1981

Effects of methandienone on the performance and body composition of men undergoing athletic training.

1. In a previous study of the effects of methandienone (Dianabol) on men undergoing athletic training, strength and performance increased, but not significantly more when the subjects were taking the drug than when they were taking placebo. The subjects did, however, gain more weight on the drug, with increases in total body potassium and muscle dimensions. It remained an open question whether the muscles had gained normal tissue or intracellular fluid. 2. In an attempt to distinguish between these possibilities the trial has been repeated, using as subjects seven male weight-lifters in regular training, and including measurements of total body nitrogen. As before, a dose of 100 mg of methandienone/day was given alternately with the placebo in a double-blind crossover experiment. The treatment periods lasted 6 weeks and were separated by an interval of 6 weeks. Body weight, potassium and nitrogen, muscle size, and leg performance and strength increased significantly during training on the drug, but not during the placebo period. 3. The finding of increased body nitrogen suggested that the weight gain was not only intracellular fluid. The increases in body potassium (436 +/- SEM 41 mmol) and nitrogen (255 +/- 69 g) were too large in proportion to the weight gain (2.3 +/- 0.4 kg) for this to be attributed to gain of normal muscle or other lean tissue, and imply gain of nitrogen-rich, phosphate-poor substance. Although this action of methandienone might be described as anabolic, the weight gain produced is not normal muscle.

Adult↗
PubMed1981

Relations between sodium transport and sodium concentration in human erythrocytes in health and disease.

1. We have examined the inter-relationships between erythrocyte sodium content and sodium transport in a group of healthy subjects and in groups of patients with disorders known to change the sodium content of erythrocytes. 2. In the healthy subjects the sodium content of erythrocytes was inversely related to both the permeability of the erythrocyte membrane to sodium (as measured by the unidirectional, ouabain-sensitive, sodium efflux) and the total activity of the sodium pumps (as measured by the rate constant of ouabain-sensitive sodium efflux). There was a correlation between the total activity of the sodium pumps and the membrane permeability to sodium. 3. Changes in the erythrocyte sodium content were due to a decrease in the activity of the sodium pumps (as in hypokalaemia and digoxin treatment), or a decrease in the permeability of the erythrocyte membrane to sodium (as in chronic renal failure) or a reduction of both the membrane permeability and the number of sodium pumps (as in hyperthyroidism or elderly patients). 4. One interpretation of the results in the healthy subjects is that there are two components of sodium influx; one associated with the sodium pumps in what we have called 'membrane-units' and the other determined by the ground permeability of the membrane. 5. On the basis of this model we suggest that in the geriatric and hyperthyroid patients there is a reduction in the number of 'membrane-units', that in hypokalaemia and during digoxin treatment there is inhibition of the sodium-pump component of the 'membrane-units' and that in chronic renal failure there is a decrease in the permeability of the membrane to sodium.

Adult↗
PubMed1981

Total body nitrogen and its relation to body potassium and fat-free mass in healthy subjects.

1. The amount of lean tissue in the body can be assessed by measuring total body nitrogen, total body potassium or fat-free mass. To compare these techniques we have measured total body nitrogen, total body potassium and fat-free mass in 91 healthy subjects (62 males, 29 females). 2. Total body nitrogen in the women and civilian men agreed closely with the few values reported previously and was closely related to total body potassium and fat-free mass. 3. The simplest estimate of total body nitrogen in a subject whose body content has not been measured is the mean value for healthy people of the same sex. The standard deviation of individual values about this mean is 253 g. The precision of the estimate can be improved considerably by predicting body nitrogen from fat-free mass (156 g) and somewhat more by predicting it from body potassium (115 g). The error of measuring total body nitrogen directly is approximately 76 g. 4. When an individual's total body potassium is measured in a search for potassium depletion, the observed value must be compared with the value expected if the subject were healthy. The standard deviation of the healthy values about the group means is 408 mmol. The precision of the estimate can be improved by predicting total body potassium from fat-free mass (SD 237 mmol), and rather more by predicting it from total body nitrogen (SD 186 mmol). If gross body composition is normal, measurement of total body nitrogen has little advantage over measurement of fat-free mass by the anthropometric technique. 5. These results suggest that the simpler measure of fat-free mass from body weight and skinfold thickness has a major role in the assessment of total body nitrogen, and thus lean body tissue, in the individual.

Adult↗
PubMed1981

The relationship between plasma lithium and the renal responsiveness to arginine vasopressin in man.

1. Arginine vasopressin (AVP) was measured in morning samples of urine from 58 patients treated with lithium for unipolar or bipolar affective disorders and from 25 healthy control subjects. 2. The AVP excretion rate was increased in the patients treated with lithium and was related to the plasma lithium concentration. The increase in AVP excretion is the result of a renal resistance to AVP so that what has been observed is an effect of lithium in vivo related to its plasma level over the therapeutic range.

Arginine Vasopressin↗
PubMed1981

Ketone kinetics in man.

1. Five normal volunteers after an overnight fast were given an injection of DL-beta hydroxybutyrate on one occasion, and an injection of acetoacetate (AcAc) on another occasion. The concentrations of D-(--)-beta-hydroxybutyrate (D-beta-OHB) and AcAc were measured every 5 minutes for 40 minutes after each injection. 2. The rate constant of disappearance (K), the volume of distribution (V) and the metabolic clearance (MCR) were calculated for the injected ketone. The values were similar for the two ketones, and therefore these values can be taken as estimates for total ketones. 3. The metabolic clearance rate of total ketones (beta-OHB plus AcAc) was also calculated from the changes in total ketone body concentration after the injection of DL-beta-OHB or AcAc which are the methods used previously. The values obtained by these methods were only 50% of that calculated from the kinetics of the injected ketone. This difference is entirely due to the differences in the apparent volume of distribution. 4. It is suggested that the best estimate of total ketone body production rate is the product of the MCR of the injected ketone and the basal concentration of total ketone bodies.

Acetoacetates↗
PubMed1981

Blood concentration and disappearance of injected alanine and beta-hydroxybutyrate in surgical patients.

The blood concentrations and the disappearance of injected beta-hydroxybutyrate (beta-OHB) and alanine were measured in 12 health subjects who had fasted overnight and in 25 surgical patients. Ten of the patients had had uncomplicated abdominal surgery two of five days before, six patients had moderate sepsis e.g. wound sepsis and nine patients had severe intra-abdominal sepsis. Separated bolus injections of beta-OHB and alanine were given intravenously and the blood concentration of the corresponding metabolite was measured over the following 40 mins. The disappearance of the injected metabolite was logarithmic, and the half-life (t 1/2) and clearance rate of the injected metabolite were calculated. The basal ketone concentration (beta-hydroxybutyrate and acetoacetate) were higher in the post operative group than in healthy subjects whereas the severely septic group had the same ketone concentration as the healthy subjects. Alanine concentration was significantly lower in the post-operative group. The t 1/2 and clearance rate of the injected metabolites were similar in all the groups for both beta-hydroxybutyrate and alanine. It is suggested that if the bolus is handled like the endogenously produced metabolite then the differences in concentration of beta-OHB and alanine in post-surgical and septic patients are likely to be due to changes in production rate.

3-Hydroxybutyric Acid↗
PubMed1981

The early and late effects of digoxin treatment on the sodium transport, sodium content and Na+K+- ATPase or erythrocytes.

1 Erythrocyte sodium content, sodium transport (ouabain sensitive sodium flux Eos, and ouabain sensitive efflux rate constant ERCos) sodium, potassium activated ouabain sensitive adenosine triphosphatase (Na+K+ATPase) and plasma digoxin were measured in patients during acute digitalisation and in patients who were on long-term digoxin treatment. 2 In the six patients who were studied during digitalisation, the ERCos and Na+K+ATPase activity decreased and erythrocyte sodium content increased during days 2-4 treatment, but there was no change in Eos. 3 In 39 patients on long term digoxin therapy (2-119 months) the erythrocyte sodium content was normal, but the erythrocyte Na+K+ATPase activity was higher than the control group. When the results from these 39 patients were divided according to the duration of treatment it was found that the erythrocyte sodium content was higher in patients treated for 2-4 months than in patients treated for longer periods and the erythrocyte Na+K+ATPase activity increased with duration of treatment. In eight patients (duration of treatment greater than 29 months) in whom ERCos and Eos were measured, ERCos and Eos were higher than the control group. 4 The results suggest that the effects of digoxin on erythrocytes which occur during acute digoxin treatment do not persist in the long term. 5 The possible explanation for the higher ERCos, Eos and Na+K+ATPase activity in patients treated with digoxin for more than 2 months is discussed.

Aged↗