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Biomedical subjects

A C MacCuish

Publications and source records attributed to A C MacCuish.

At least 73 records · Page 4Linked to original sources
PubMed1986

Increased blood viscosity in diabetic proliferative retinopathy.

Blood rheology and haemostasis were assessed in 18 diabetics with proliferative retinopathy and in 18 diabetics without proliferative retinopathy, matched for age, sex, smoking habit and type, duration and treatment of diabetes. Proliferative retinopathy was associated with significantly higher levels of blood viscosity at high and low shear rates, which were related to higher levels of plasma viscosity and fibrinogen. Blood urea, glucose, glycosylated haemoglobin and white cell count were also significantly higher, whereas haematocrit, red cell deformability and several other haematological and biochemical variables did not differ significantly in the 2 groups. In view of these findings, and of our recent demonstration that increased blood viscosity also exists in those patients with retinal vein occlusion who develop a similar proliferative retinopathy, we suggest that hyperviscosity may contribute to retinal ischaemia and hence proliferative retinopathy.

Adult↗
PubMed1985

Evaluation of Visidex II--a new strip for blood glucose measurement.

We have evaluated a new blood glucose test-strip (Visidex II, Ames), which does not require washing with water after contact with blood. Visidex II showed a significant negative bias when compared with a similar diagnostic strip (BM 20-800, Boehringer) and with the Beckman II glucose analyser (p less than 0.001 in both cases), and a poorer correlation with either method than BM strips with the Beckman II. A significant number (6.3%) of Visidex strips in this study were unreadable due to removal of the colour pads on blotting, and some difficulty was reported by patients in reading values around 6-8 mmol/l. Visidex II can safely be stored in the refrigerator and developed strips may be stable longer than BM strips. A significant error in reading was noted if the incubation time was varied by +/- 5 seconds. Further experience and perhaps some modifications may be necessary before Visidex II can be recommended for widespread use.

Blood Glucose↗
PubMed1985

Effect of sulphonylurea administration on insulin secretion and amino acid metabolism in non-insulin-dependent diabetic patients.

Sulphonylureas lower blood glucose but other metabolic effects have been little studied. In an assessment of carbohydrate and amino acid metabolism in 9 patients with non-insulin-dependent diabetes mellitus (NIDDM) before and after 3 months' therapy with gliclazide, glycaemic control was improved (mean +/- S.D. glycosylated haemoglobin 13.8 +/- 1.9% before therapy, 10.2 +/- 2.1% after therapy (p less than 0.01], but fasting amino acid levels were not altered. In contrast, postprandial levels of branched chain amino acids (BCAA) were significantly reduced: total BCAA (valine, leucine, and isoleucine) 120 mins following a standard test meal fell from 717 +/- 71 mumol/l before therapy to 600 +/- 90 mumol/l after 3 months' therapy (p less than 0.01). This finding implies an increased action of endogenous insulin on skeletal muscle to promote uptake of BCAA postprandially and, in accord with this, peripheral insulin levels were significantly increased following drug treatment (peak insulin level 55.6 +/- 20.2 mU/l before therapy, 91.3 +/- 17.9 mU/l after therapy (p less than 0.01]. Sulphonylurea drugs therefore do not simply have a hypoglycaemic action but also affect amino acid metabolism in NIDDM patients.

Adult↗
PubMed1985

Comparison of oral glucose loading and intravenous glucagon injection as stimuli to C-peptide secretion in normal men.

In 10 healthy men, we have compared the respective effects of an intravenous injection of glucagon (1 mg) and an oral glucose load (75 G) in eliciting the release of C-peptide and insulin from the pancreas. Serum C-peptide and insulin concentrations increased respectively to median values of 190% and 500% at 6 minutes after glucagon injection, and 344% and 794% at 30 minutes and 268% and 278% at 60 minutes following glucose ingestion. The oral glucose load was as effective as glucagon injection in testing beta cell function and was free from the unpleasant side effects (nausea, vomiting, syncope) commonly associated with glucagon. We conclude that oral glucose loading is probably the test of choice to elicit C-peptide release when screening populations of normal subjects for adequacy of beta cell function.

Adult↗
PubMed1985

Glycosylated albumin and glycosylated proteins: rapidly changing indices of glycaemia in diabetic pregnancy.

Serial measurements of glycosylated albumin (GAlb), glycosylated plasma proteins (GPP) and glycosylated haemoglobin (GHb) were performed by affinity chromatography throughout the course of pregnancy in 14 insulin-dependent diabetic women. In patients whose glycaemic control improved markedly during pregnancy, the concentrations of GAlb and GPP decreased by more than 50 per cent after four weeks of good diabetic control. By contrast, the rate of decrease in GHb levels in the same patients was significantly less and did not indicate a comparable improvement in glycaemia until 12 weeks after good diabetic control was established. Elevated concentrations of GAlb or GPP decrease much more rapidly than GHb concentration when diabetic control is improved; thus measurement of glycosylated proteins is a valuable adjunct to serial blood glucose monitoring in clinical circumstances such as diabetic pregnancy, where early confirmation of good diabetic control is important.

Adult↗
PubMed1984

Dissociation of adrenarche and gonadarche in diabetes mellitus.

Serum concentrations of testosterone and dehydroepiandrosterone sulphate (DHAS) have been measured in 10 stable insulin-dependent diabetic (IDD) males (chronological age (CA) range 13.0-17.5 years). Their results have been compared with those of a control population of 69 non-diabetic males who presented with mild constitutional growth delay and whose skeletal maturity and pubertal development were similar to the diabetic subjects. Within bone ages (BA) 11.0-14.5 years no significant difference was observed between the serum testosterone concentrations of the diabetic patients and controls: diabetic males, 8.2 (0.3-25) nmol/l (median and range); controls, 7.0 (less than 0.3-23) nmol/l. In contrast, within BA 11.0-14.5 years, the diabetic males had significantly lower serum DHAS concentrations: diabetic males, 1.1 (0.7-4.2) mumol/l; controls, 3.7 (0.7-5.6) mumol/l (P less than 0.001). The serum DHAS concentrations of the diabetic males were also significantly lower than the controls when matched separately for pubic hair and genital development, testicular volume and serum testosterone, (in each comparison P less than 0.02). Serum DHAS concentrations of the diabetic males did not correlate significantly with CA, BA, BA delay (CA-BA), age of onset of diabetes, duration of diabetes, or glycosylated haemoglobin (GHb), but significant correlation was observed between BA delay and duration of diabetes, r = 0.65, P less than 0.05. We conclude that gonadarche appears to proceed despite delayed adrenarche in IDD males. This study presents further evidence in favour of adrenarche and gonadarche being independent physiological events. The causes and clinical significance of low serum DHAS concentrations in adolescent diabetic males remain to be established.

Adolescent↗
PubMed1984

Effects of diabetic control and biosynthetic human insulin on blood rheology in established diabetics.

Blood rheology (blood viscosity, haematocrit, plasma viscosity, erythrocyte sedimentation and deformability) was measured in 22 diabetics in a study to compare animal insulins with biosynthetic human insulin. All rheological variables were significantly abnormal in the diabetics when compared with matched normal controls, and were not influenced by the type of insulin injected. However, blood rheology was related to diabetic control, as judged by glycosylated haemoglobin levels; when diabetic control was worst (mean glycosylated haemoglobin 11%), blood viscosity was significantly higher and red cell deformability significantly lower than when control was at its best (mean glycosylated haemoglobin 9.5%). A similar correlation between mean red cell deformability and mean glycosylated haemoglobin was found when individual diabetics were compared (r = 0.66; p less than 0.001). The occurrence of abnormal blood viscosity and red cell deformability during periods of poor diabetic control may contribute to the development of diabetic vascular complications.

Adolescent↗
PubMed1984

Insulin antibodies in the maternal and foetal circulation of pregnant diabetic women treated with human insulin of recombinant DNA origin.

Thirteen diabetic women were treated with human insulin of recombinant DNA origin from early pregnancy. One patient previously treated with conventional beef insulin showed a steady fall in insulin antibody levels whilst those previously treated with purified porcine insulin or human insulin showed no changes in species-specific insulin binding or in antibody-bound insulin. Two women with gestational diabetes, who received insulin for the first time during pregnancy, developed insulin antibodies which declined when therapy was withdrawn in the post-partum phase. Insulin antibody was detectable in the foetal circulation in all pregnancies at parturition but did not seem to be associated with any deleterious effect on carbohydrate metabolism in the neonate. Human insulin of recombinant DNA origin is a satisfactory treatment for diabetic pregnancy, is preferable to the use of conventional beef insulins in these patients and may confer a lesser risk of neonatal hypoglycaemia than purified pork insulin.

Adult↗
PubMed1984

Serum growth hormone (GH) and the responses to thyrotropin-releasing hormone (TRH) in diabetes mellitus: lack of evidence for TRH evoked GH secretion.

Since TRH has been reported to evoke GH secretion in diabetic patients, we have investigated the influences of the enhanced GH secretion normally seen in diabetic patients on this response by measuring serum GH concentrations in 27 non-ketotic, stable, insulin-dependent diabetic (IDD) patients (14 male, 13 female). GH concentrations were measured over periods of 1 hr prior to and 1 hr following IV administration of both 200 micrograms TRH and 2 ml N Saline given on separate days. GH concentrations were not statistically significantly different between males and females during the two 120 min test periods and in individual patients GH concentrations did not differ significantly at any time during the tests. Sixteen of the 27 patients (Group 1) demonstrated elevation of serum GH following TRH, which was not statistically different from 11 of 27 patients who showed increased GH concentrations following saline administration. Seven subjects (4 male, 3 female) had a higher peak GH concentration following TRH than during their own 2 pre-injection test periods or following saline. Eleven patients failed to show any GH rise following IV TRH (Group 2). During the TRH test periods integrated GH concentrations in Group 1 patients were not statistically significantly different from those of Group 2: Group 1, 7.1 (0.7-15.8) (median and range) mU.min.l(-1), Group 2, 2.7 (0.4-25.4) mU.min.l(-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetes Mellitus, Type 1↗
PubMed1982

Biosynthetic human insulin in the treatment of diabetes. A double-blind crossover trial in established diabetic patients.

94 diabetic patients established on treatment with porcine (n = 47) or bovine (n = 47) insulin took part in a double-blind crossover trial, in which 6-week periods of treatment with the appropriate animal insulin were compared with periods of treatment with biosynthetic human insulin (BHI). 6 patients withdrew during the trial, in 3 cases because of hypoglycaemia while taking BHI. In bovine-insulin-treated patients, the mean glucose level (mean of seven capillary-blood samples over 1 day), the modified M index, and total daily insulin requirement were the same on BHI and bovine-insulin treatment. For porcine-insulin-treated patients, mean glucose level and the modified M index were slightly higher on BHI than on porcine-insulin treatment (9.7 vs 9.0 mmol/l and 79.6 vs 65.0, respectively), despite an average increase of 2.3 units/day of BHI after 6 weeks of such treatment. Hypoglycaemic episodes were not significantly more or less frequent on BHI in either group of patients. In both groups fasting blood glucose was higher during BHI treatment than during animal-insulin treatment (14.2 vs 12.8 mmol/l [bovine group]; 12.1 vs 9.6 mmol/l [porcine group]). In bovine-insulin-treated patients blood glucose before the evening insulin injection was higher on BHI than on bovine insulin (11.6 vs 10.0 mmol/l). BHI appears to be a safe alternative to porcine or bovine insulin. Differences in the pharmacokinetics of BHI may account for the observed differences in blood-glucose responses.

Adult↗
PubMed1981

Changes in glycosylated haemoglobin after oral glucose load.

To study the relation between hyperglycaemia and a change in the concentration of glycosylated haemoglobin (HbA1) blood glucose and HbA1 concentrations were measured during an oral glucose tolerance test and for 120 days afterwards in 20 normal subjects. These measurements showed that a minor degree of hyperglycaemia led to a significant increase in lycosylated haemoglobin concentrations. The increase appeared 10 days after the test, and values remained raised until 30 days and returned to normal 60 days after the test. If such a minor fluctuation of blood glucose can lead to a significant increase in HbA1 concentrations the test may be too sensitive as an index of long-term blood glucose control in diabetics.

Adult↗
PubMed1981

Serious retinopathy in a diabetic clinic: prevalence and therapeutic implications.

In a series of 1000 patients examined consecutively in a large diabetic clinic, 95 (9.5%) were classified as having serious diabetic retinopathy. The definition was confined to exudative retinopathy (macular oedema or hard exudates encroaching upon the macula), proliferative retinopathy, and retinal ischaemia (as evidenced by the presence of soft exudates in the absence of hypertension, together with characteristic vascular changes). The diagnosis of serious diabetic retinopathy is always accompanied by a need for specialised ophthalmological assessment (including fluorescein angiography) and, often, urgent photocoagulation. Investigation and treatment are time-consuming, and such patients therefore constitute a major workload for the ophthalmological services: the average time for an ophthalmic consultation was found to be 20 min, and when fluorescein angiography was added to this the time increased to 40 min. The average time spent on photocoagulation for neovascularization was 2 h for each eye, and for exudative retinopathy 30 min for each eye.

Adult↗
PubMed1980

Blood viscosity in young male diabetics with and without retinopathy.

Blood viscosity (shear rates 100s-1 and 0.94s-1) and several of its major determinants (haematocrit, plasma fibrinogen and plasma viscosity) have been measured in 38 male insulin-treated diabetics, aged 18-50 years, and in 38 non-diabetic control subjects matched for age and smoking habit. Diabetics without fundoscopic retinopathy (n=20) had higher mean blood viscosity than controls at the high shear rate (7.07 cP vs 6.75 cP, p < 0.05) and the low shear rate (21.2 cP vs 18.7 cP, p < 0.025). These differences persisted after correction of blood viscosity to a standard haematocrit, and were associated with increased plasma viscosity (1.41 cP vs 1.34 cP, p < 0.025) and plasma fibrinogen (2.9 g/L vs. 2.5 g/L, p < 0.025). Diabetics with retinopathy (n = 18) had higher mean blood viscosity than diabetics without retinopathy at the high shear rate (7.53 cP vs 7.07 cP, p < 0.05) and the low shear rate (24.3 cP vs. 21.2 cP, p < 0.05), associated with a higher haematocrit (p < 0.05). Blood viscosity and haematocrit correlated with the duration of diabetes (r > 0.32, p < 0.05).

Adolescent↗