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Biomedical subjects

A D Wright

Publications and source records attributed to A D Wright.

At least 91 records · Page 5Linked to original sources
PubMed1990

Qualitative and quantitative abnormalities of von Willebrand antigen in patients with diabetes mellitus.

Previous reported studies of vVWf antigen (vWf:Ag) in patients with diabetes mellitus have not shown qualitative abnormalities despite frequent documentation of raised vWf:Ag. Twenty two patients with established diabetes mellitus have been studied and qualitative abnormalities of vWf:Ag multimers were found in 10 patients who had poorer glycaemic control (as judged by plasma fructosamine) than the other 12 patients. Seven of the 22 patients were restudied after a 3 month period of improved glycaemic control and the vWf:Ag multimer abnormalities disappeared in 6 of these. Some of the structural abnormalities were accompanied by loss of vWf functional activity. As vWf:Ag is synthesised in the endothelial cell, vWf:Ag abnormalities during periods of poor glycaemic control may reflect endothelial cell damage with vWf:Ag release and possibly subsequent proteolysis.

Antigens↗
PubMed1990

Changing sex ratio in diabetic ketoacidosis.

An annual audit of diabetic ketoacidosis and hyperosmolar non-ketotic state was made in one hospital from 1971 to 1988. There were 846 episodes of ketoacidosis and 126 episodes of hyperosmolar state. A relative fall occurred in the number of episodes of ketoacidosis compared with hyperosmolar state over this time (p less than 0.05), and there was a change of female:male ratio for episodes of ketoacidosis occurring in established diabetes from 2.79 to 1.59 (p less than 0.01). In contrast the female:male ratio remained unchanged (mean 1.16) for episodes of hyperosmolar state and remained less than 1.0 for all episodes of ketoacidosis in previously undiagnosed diabetes mellitus. Among patients who suffered recurrent ketoacidosis there was a reduction in the number of episodes occurring in female patients and an increase in the number of episodes occurring in male patients in each successive 6-year period with consequent change in female:male ratio for this subgroup from 7.33 to 4.75 to 1.12 (p less than 0.001).

Adolescent↗
PubMed1990

Cerebral blood flow in acute mountain sickness.

Changes in cerebral blood flow (CBF) were measured using the radioactive xenon technique and were related to the development of acute mountain sickness (AMS). In 12 subjects, ascending from 150 to 3,475 m, CBF was 24% increased at 24 h [45.1 to 55.9 initial slope index (ISI) units] and 4% increased at 6 days (47.1 ISI units). Four subjects had similar increases of CBF when ascending to 3,200 m 3 mo later, indicating the reproducibility of the measurements. In nine subjects, ascending from 3,200 to 4,785-5,430 m, CBF increased to 76.4 ISI units, 53% above estimated sea-level values. CBF and increases in CBF were similar in subjects with or without AMS. In six subjects, CBF was measured before and after therapeutic intervention. At 2 h CBF increased 22% (71.3 to 87.3 ISI units) above pretreatment values in three subjects given 1.5 g acetazolamide, while three subjects given placebo showed no change. Symptoms remained unaltered in all subjects during the 2 h of the study. Overall, the results indicated that increases in CBF were similar in subjects with or without AMS while acetazolamide-provoked increases of CBF in AMS subjects caused no acute change in symptoms. Alterations in CBF cannot be directly implicated in the pathogenesis of AMS.

Acetazolamide↗
PubMed1989

Xiaoke tea, a Chinese herbal treatment for diabetes mellitus.

Xiaoke tea, a traditional Chinese treatment for diabetes mellitus, lowered blood glucose concentrations in streptozotocin diabetic mice. To investigate Xiaoke clinically, a double-blind crossover study was undertaken in 12 non-insulin-treated diabetic patients. Xiaoke tea and ordinary tea (infusion of 2.72 g, 4 times daily) were consumed in random order for 4 weeks. A standard breakfast meal was taken before and after each treatment period. Xiaoke did not significantly affect glycosylated haemoglobin, basal or post-breakfast serum glucose and insulin concentrations, intermediary metabolite concentrations, triglyceride and cholesterol. No adverse side-effects of Xiaoke were evident.

Blood Glucose↗
PubMed1989

The effects of verapamil, diltiazem, nifedipine and propranolol on metabolic control in hypertensives with non-insulin dependent diabetes mellitus.

The effects of one month's treatment with each of nifedipine, verapamil, diltiazem, propranolol and placebo, given in random order, on fasting plasma glucose, haemoglobin Alc, serum fructosamine, immunoreactive insulin, cholesterol, and triglyceride were studied in a group of 19 patients with hypertension and non-insulin dependent diabetes mellitus. The metabolic effects of the active drugs were generally small but fasting plasma glucose was increased by propranolol from 9.3 +/- 3.0 to 10.4 +/- 3.4 mmol/l (P less than 0.01) (mean +/- SD) and to 10.1 +/- 3.2 mmol/l (P less than 0.05) by nifedipine. Serum fructosamine was increased from 2.75 +/- 0.53 to 2.89 +/- 0.62 mmol/l (P less than 0.05) by diltiazem and to 2.91 +/- 0.65 (P less than 0.05) by propranolol. Verapamil increased fasting serum immunoreactive insulin: diltiazem and propranolol tended to reduce it. Propranolol but not the other drugs significantly increased serum triglyceride. Calcium antagonists may be preferable to beta adrenoceptor blockers for the treatment of hypertensive diabetics. Of the three calcium antagonists we studied, verapamil may have advantages over nifedipine and diltiazem.

Aged↗
PubMed1988

Diuretics and hyperkalaemia in diabetic ketoacidosis.

Diabetic ketoacidosis (DKA) often presents with hyperkalaemia. We investigated whether it was more likely in patients taking potassium-retaining diuretics. A retrospective survey of all patients (552 cases) presenting in DKA between 1974 and 1984 was undertaken. Initial biochemical data were compared for patients recorded as taking potassium-retaining diuretics (7 cases) at the time of presentation with those taking potassium-losing diuretics (13 cases), and age matched control groups were selected from those who presented in DKA but were not taking diuretics. There was no significant difference in initial serum potassium levels between the diuretic treated groups. The serum sodium was higher in the control group than in the potassium losing group (p = 0.045) and the serum urea significantly lower (p = 0.045). We conclude that potassium-retaining diuretics do not predispose to hyperkalaemia in diabetic ketoacidosis.

Adult↗
PubMed1988

Recurrent diabetic ketoacidosis.

In a study over 15 years, 740 episodes of diabetic ketoacidosis occurred in 505 patients. A total of 113 patients had more than one episode. The majority (90%) of recurrences were within 4 years of the initial episode. Taking a definition of recurrent ketoacidosis as three or more episodes within 4 years, 39 patients were identified. Two subgroups appeared prone to such frequent recurrences, namely girls less than 20 years of age and women more than 59 years of age. A variety of causes of recurrent episodes was noted in the young patients but in the older patients other chronic illnesses complicated the diabetes. The need for good domiciliary supervision of elderly chronic sick patients who require insulin is emphasized.

Diabetic Ketoacidosis↗
PubMed1987

Blood fuel metabolites in asthma during and after progressive submaximal exercise.

Ten male stable asthmatic subjects and 10 matched control subjects performed a progressive exercise test on a treadmill to 85% of their predicted maximum heart rate. Blood lactate, pyruvate, hydrogen ion, glucose, alanine, glycerol and total ketone body concentrations were measured at frequent intervals during and up to 60 min after exercise. Carbon dioxide production, oxygen consumption, ventilation, respiratory exchange ratio and oxygen saturation were also measured during and up to 10 min after exercise. There were no significant differences between the asthmatic and control subjects in levels of carbon dioxide production, oxygen consumption and ventilation. The respiratory exchange ratio was greater in the asthmatic subjects during recovery from exercise (P less than 0.05). No changes in oxygen saturation were observed during exercise in either group. In both asthmatic and control subjects, lactate, pyruvate, hydrogen ion, alanine and glycerol concentrations showed an increase from baseline levels, reaching maximum levels up to 10 min after exercise and returning to baseline within 1 h after exercise. Total ketone body concentrations decreased during exercise. There were no significant differences between the asthmatic and control subjects in the concentration of any metabolite over the study period. These data indicate that fuel metabolism during and after short-term progressive exercise is similar in stable asthmatic and normal subjects.

Adult↗
PubMed1987

Blood lactate changes during exercise at high altitude.

Blood lactate concentrations were measured in 18 normal subjects at the end of an exercise test designed to maintain heart rate at 85% of maximum for 15 minutes. Blood lactate concentrations were reduced at high altitude (4846 m) and correlated positively with basal pH and negatively with basal Pa,O2 levels. Blood lactate concentrations tended to be lower in those subjects on acetazolamide but were not correlated with the severity of acute mountain sickness or with the workload of the exercise test. We conclude that the pH changes are probably the most significant factor in reducing lactate concentrations.

Acetazolamide↗
PubMed1986

Increased circulating radioreceptor-active growth hormone in insulin-dependent diabetics.

A radioreceptor assay (RRA) for GH, using pregnant rabbit liver membranes, was used to evaluate the receptor-hormone interaction of circulating (serum) GH in diabetics. Multiple morning blood samples were taken from 18 fasted insulin-dependent diabetics on three occasions and assayed for GH by the RRA and radioimmunoassay (RIA). Samples from 12 normal subjects (GH secretion stimulated by exercise and hypoglycaemia) and 11 acromegalics were also studied. The RRA/RIA ratio was higher in samples from the acromegalics than in normal subjects (0.85 vs 0.65, P less than 0.01) and only a few samples had RRA values greater than RIA. All the samples from 14 of the diabetics had lower RRA values than RIA, but 40% (39 of 96) of samples from the remaining four diabetics had RRA concentrations markedly in excess of the levels measured by RIA. Sephadex chromatography (G100) of serum samples revealed similar proportions of immunoreactive GH forms in the diabetics with high RRA values compared with the diabetics with low RRA values. These findings may indicate intermittent secretion of highly bioactive GH in some insulin-dependent diabetics. Further studies on the biological properties of circulating GH are needed to clarify the role of GH secretion in the development of diabetic microvascular complications.

Acromegaly↗
PubMed1986

Circulating growth hormone forms in type 1 diabetic subjects: comparison with normal subjects and acromegalics.

The molecular forms of growth hormone (GH) in serum from 18 Type 1 diabetic patients with poor metabolic control were analysed using sephadex G-100 chromatography. The profiles obtained were compared with those from normal subjects whose GH secretion was stimulated by exercise and hypoglycaemia and eight acromegalic patients. In the three groups three distinct GH forms were found: little (monomeric), big and big-big-GH. Samples from normal subjects contained 45% little-GH which was less than samples from the diabetics and acromegalics (53% and 65%, respectively, P less than 0.01). Further samples from normal subjects after the onset of hypoglycaemia showed an increase in little-GH. In the three groups, the higher the proportion of little-GH, the lower the proportion of big-big-GH, while the proportion of big-GH remained similar. In the acromegalics the proportion of little-GH was strongly correlated with the log concentration of serum GH. As little-GH is cleared from the circulation quicker than the larger forms these data indicate that the main component of the frequent surges of GH secretion in poorly controlled Type 1 diabetic subjects is little-GH (monomeric forms). The sustained release of GH found in acromegaly is composed largely of monomeric forms.

Acromegaly↗
PubMed1986

Clinical characteristics and aetiological classification of insulin-dependent diabetes in the elderly.

In a prospective study of 195 newly-diagnosed diabetic patients aged 65 years or over, 80 (41.0 per cent) were treated initially by diet, 89 (45.6 per cent) by diet and oral hypoglycaemic agents, and 26 (13.3 per cent) by diet and insulin. Fifteen patients (7.7 per cent) died within a year of diagnosis. Of 26 patients treated with insulin, six died in the first year, 14 were successfully transferred to diet and oral agent treatment and six continued on insulin--two of whom failed to a trial of oral agents, two showed only a temporary response and two received no trial. A further nine patients were taking insulin 12 months after diagnosis because of no response (eight patients) or a transient response (one patient) only to oral agents. Age, percentage ideal body weight, history of acute onset, blood glucose, glycosylated haemoglobin, and random C-peptide concentration at diagnosis did not discriminate between patients requiring insulin at 12 months and those successfully treated without insulin. Patients who were insulin-dependent 12 months after diagnosis had an increased frequency of ketonuria at diagnosis and a previous medical history of endocrine disease. In insulin-dependent patients there was an increased frequency of HLA DR3 but not DR4 and an increased frequency of thyroid microsomal and gastric parietal cell antibodies but not islet cell antibodies. It is concluded that elderly newly-diagnosed diabetic patients who are treated at diagnosis with insulin are not necessarily insulin dependent and can be given a trial of oral agents with safety.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗