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Biomedical subjects

B F Clarke

Publications and source records attributed to B F Clarke.

180 records · Page 10Linked to original sources
PubMedDate not supplied

Painful myocardial infarction in severe diabetic autonomic neuropathy.

Two cases are reported of painful myocardial infarction in diabetics with severe autonomic neuropathy confirmed by abnormal autonomic function tests. Painless myocardial infarction in diabetics has traditionally been attributed to damage of cardiac pain fibres by autonomic neuropathy but other factors such as microangiopathy in the myocardium may be responsible. It may simply be that diabetics come into hospital more often for other reasons and a silent myocardial infarction diagnosed incidentally.

Adult↗
PubMedDate not supplied

Multiple complications in severe diabetic ketoacidosis. A short review of the literature.

Diabetic ketoacidosis may be associated with a wide variety of complications, some of which are uncommon and not widely appreciated. A case of severe ketoacidosis with multiple complications including septicaemia, pneumomediastinum, gastro-intestinal haemorrhage, magnesium depletion and multiple mononeuropathy is reported in a 17-year old girl who made a successful recovery. The patient had not taken insulin for almost 4 days, had no preceding illness and was admitted in a near moribund state with hypothermia (34.2 degrees C), hypotension (80/50) and an arterial pH less than 6.8. There was a leukocytosis 41,200, the blood culture grew haemolytic streptococci and chest radiology showed pneumomediastinum. I.v. therapy was continued for some days and the patient developed clinical features of magnesium depletion. During the recovery period she developed multiple mononeuropathy. A brief review of these complications is given.

Adolescent↗
PubMedDate not supplied

Testing for heart rate variation in diabetes: single or repeated deep breaths?

Heart rate variation during three periods of single deep breaths and three periods of repeated deep breathing at 6 breaths/min was compared in 14 normal and 40 diabetic subjects. There were no differences between the two methods in either normals or diabetics, but the coefficient of variation was significantly smaller using the repeated deep breaths method. When the 6 periods of breathing were analysed separately, no 'training' effect could be detected. The first breath of the repeated deep breaths consistently produced the largest heart rate variation in 29% of the normals and 17% of the diabetics. We conclude that there is no advantage in using the single deep breath method to assess cardiac parasympathetic function in diabetics over the currently used 6 repeated deep breaths/min.

Adolescent↗
PubMedDate not supplied

Reduced venous compliance and increased transcapillary escape of protein in insulin-dependent diabetic patients.

Lower limb venous compliance and transcapillary escape rate of transferrin were measured in eight normotensive, insulin-dependent male diabetic patients and eight control subjects using a dual isotope technique. Technetium-99m labelled autologous erythrocytes were used to measure venous compliance and to correct for local changes in blood volume, whilst Indium-113m labelled transferrin was used to measure transcapillary escape of protein. The diabetic patients were found to have reduced venous compliance 1.5 (0.7 to 3.4) x 10(-2) mmHg-1 compared with controls 3.2 (2.4 to 4.1) x 10(-2) mmHg-1 (p less than 0.01). The diabetic patients were also found to have greater transcapillary escape of transferrin -2.7 (-1.5 to -5.3) x 10(-3), compared with control subjects -5.2 (-4.1 to -8.1) x 10(-3) (p less than 0.02) in response to increasing hydrostatic pressure. These results show reduced venous compliance in patients with a mean duration of diabetes of 15 years and with only at most, early complications of diabetes, and confirm previous observations showing increased transcapillary escape of protein.

Adult↗
PubMedDate not supplied

Blood glucose control determines the renal haemodynamic response to angiotensin converting enzyme inhibition in type 1 diabetes.

Elevation of glomerular filtration rate (GFR) is a feature of diabetes mellitus in humans and in animal models. Angiotensin II has been implicated as a mediator of GFR in diabetes. The acute effect of inhibition of angiotensin converting enzyme with captopril on renal haemodynamic and endocrine parameters was therefore studied in 14 normotensive male Type 1 diabetic patients, and the responses compared with those in five normal male control subjects. Following captopril 12.5 mg orally the diabetic patients exhibited an acute fall in GFR from 122 +/- 3.8 to 113 +/- 4.5 ml min-1 1.73-m-2 (p less than 0.02) and a rise in renal plasma flow (RPF) from 670 +/- 57 to 797 +/- 46 ml min-1 1.73-m-2 (p less than 0.01) which resulted in a fall in filtration. This did not occur in normal control subjects. Natriuresis occurred only in normal control subjects. There was no change in urinary excretion of PGE2 or kallikrein in either group but excretion of 6-keto-PGF1 alpha fell in the diabetic patients. There was a significant correlation between glycosylated haemoglobin and baseline RPF (rs = -0.79, p less than 0.001) and filtration fraction (rs = 0.83, p less than 0.001) that persisted when the change in these variables following captopril was analysed. Our results are compatible with the response to ACE inhibition in diabetic patients being secondary to inhibition of angiotensin II and suggest that this response may be related to blood glucose control.

Adult↗
PubMedDate not supplied

Comparison of intravenous glucagon and dextrose in treatment of severe hypoglycemia in an accident and emergency department.

Hypoglycemia is a serious problem in insulin-treated diabetic patients. In this study the efficacy of intravenous glucagon (1 mg) was compared with that of intravenous dextrose (25 g) in the treatment of hypoglycemia in insulin-treated patients attending an accident and emergency department. In addition, the prevailing glycemic control of these patients was compared with patients routinely attending a diabetic outpatient clinic. Both intravenous glucagon and dextrose were effective in the treatment of hypoglycemic coma. There was a difference in the glycemic profile after intravenous glucagon compared with intravenous dextrose, and recovery of a normal level of consciousness after glucagon was slower than after dextrose (6.5 vs. 4.0 min, respectively; P less than .001), although the average duration of hypoglycemic coma was 1.4 h. The glucagon- and dextrose-treated groups had significantly lower HbA1 than comparable patients routinely attending the clinic (9.5 +/- 0.8 vs. 12.0 +/- 3.8%, respectively; P less than .001). In view of the ease of administration and the small risk of vascular and extravascular complications, intravenous glucagon appears to be a useful alternative to intravenous dextrose in the treatment of severe hypoglycemia.

Blood Glucose↗
PubMedDate not supplied

Provocation of postural hypotension by nitroglycerin in diabetic autonomic neuropathy?

The effect of nitroglycerin on heart rate and systolic blood pressure was compared in 5 normal subjects, 12 diabetic subjects without autonomic neuropathy, and 5 diabetic subjects with autonomic neuropathy. The magnitude and time course of the increase in heart rate and the decrease in systolic blood pressure after nitroglycerin were similar in the normal and diabetic subjects without autonomic neuropathy, whereas a lesser increase in heart rate and a greater decrease in systolic blood pressure occurred in the diabetic subjects with autonomic neuropathy. It is therefore suggested that caution should be exercised when prescribing vasodilator drugs in diabetic patients, particularly those with autonomic neuropathy.

Adolescent↗
PubMedDate not supplied

Effect of alcohol intake on symptomatic peripheral neuropathy in diabetic men.

In a group of 541 white diabetic men aged 20--59 yr attending one clinic it was found that 91 (15%) drank heavily, while a further 39 (7%) had frank alcoholism. The prevalence of symptomatic peripheral neuropathy was much higher in the 120 men who drank excessively. It is considered important, therefore, when treating diabetic patients with peripheral neuropathy not to assume that the diabetes itself is the cause in all cases. The alcoholic intake of the patient should be ascertained and, if excessive, it should be pointed out to the patient that this may well be the predominant factor causing symptoms.

Adult↗
PubMedDate not supplied

Small muscle wasting of the hands in diabetes mellitus.

The clinical features and peripheral somatic and autonomic nerve function were studied in 10 diabetic subjects (nine men, one woman; mean age 59 yr, range 41-68 yr; mean duration of diabetes 20 yr, range 8 mo to 33 yr) with generalized small muscle wasting of the hands. Five patients were insulin-dependent and five non-insulin-dependent. Nine had retinopathy (two proliferative, seven background), five nephropathy, two ischemic heart disease, and seven peripheral vascular disease. Nine patients had clinical evidence of sensory peripheral neuropathy and absent reflexes in the lower limbs. Eight patients had distal sensory impairment and/or absent reflexes in the upper limbs. Seven had two or more symptoms of autonomic neuropathy. Nerve conduction measurements in the median, ulnar, and lateral popliteal nerves showed that all patients had moderate to severe polyneuropathy affecting both motor and sensory fibers. Nine had one or more abnormal cardiovascular autonomic function tests. Electromyography of affected muscles in the hands showed changes of chronic partial denervation and collateral reinnervation in all cases.

Adult↗
PubMedDate not supplied

Prediction of diabetic retinopathy from clinical variables and color vision data.

Predictions about the onset of retinopathy in 295 diabetic patients, all originally having no evidence of retinopathy, have been made in a longitudinal study over 7 yr. Out of many color vision tests and clinical variables, the best individual predictor was a measure of yellow-blue discrimination, using an anomaloscope. The other predictors of significance were the degree of blood glucose control and the duration of diabetes. Although the predictions from a linear logistic model were significant in classifying the diabetic subjects into those whose fundus will remain normal and those in whom it will develop retinopathy, the number of misclassifications was substantial. An examination of the goodness of fit between the data and the model suggested a criterion value (P) of around P = 0.3 for the probability that a patient develops retinopathy. At this value, the probability of being normal for an individual classed as normal was 0.82, and the probability of developing retinopathy for an individual classed as having retinopathy was 0.54.

Adult↗
PubMedDate not supplied

Decreased skin wrinkling in diabetes mellitus.

Skin wrinkling, which may be dependent on peripheral autonomic innervation, was assessed in 100 normal and 42 diabetic subjects using a temperature-controlled water bath with immersion of the hands for 30 min. Markedly decreased skin wrinkling was observed in diabetic subjects and in manual workers, but did not correlate with cardiovascular tests of autonomic function, control, type or duration of diabetes, or diabetic complications. The cause of decreased skin wrinkling in people with diabetes is unexplained.

Adult↗
PubMedDate not supplied

The value of cardiovascular autonomic function tests: 10 years experience in diabetes.

Five simple, noninvasive cardiovascular reflex tests have been used to assess autonomic function in one center over the past 10 yr. Seven hundred seventy-four diabetic subjects were tested for diagnostic and research purposes. In 543 subjects completing all five tests, abnormalities of heart rate tests occurred in 40%, while abnormal blood pressure tests occurred in less than 20%. Their results were grouped as normal (39%), early (15%), definite (18%), and severe (22%) involvement. Six percent had an atypical pattern of results. Two hundred thirty-seven diabetic subjects had the tests repeated greater than or equal to 3 mo apart: 26% worsened, 71% were unchanged, and only 3% improved. The worsening followed a sequential pattern with first heart rate and later additional blood pressure abnormalities. Comparison between a single test (heart rate response to deep breathing) and the full battery in 360 subjects showed that one test alone does not distinguish the degree or severity of autonomic damage. These tests provide a useful framework to assess autonomic neuropathy simply, quickly, and noninvasively.

Adolescent↗
PubMedDate not supplied

Effects of sorbinil treatment on erythrocytes and platelets of persons with diabetes.

Thirty-three diabetic subjects were given the aldose reductase inhibitor sorbinil (Pfizer, UK) for 3 wk. There was a significant fall in mean erythrocyte sorbitol concentration over this period. In all subjects erythrocyte sorbitol concentrations after treatment were within or below the range found in normal subjects. No changes in erythrocyte 2,3-diphosphoglycerate (2,3-DPG) or myo-inositol concentrations, plasma beta-thromboglobulin (beta-TG) concentration, or P50--a measure of the oxygen affinity of hemoglobin--were observed. There was a high incidence of adverse reactions to the drug.

Adult↗
PubMedDate not supplied

Bacteriuria and autonomic nerve function in diabetic women.

Significant bacteriuria (viable count greater than or equal to 10(5)/ml) was found on single testing in 10% of 400 consecutive diabetic women aged 15-65 yr routinely attending a diabetic clinic. Twenty patients with and 21 without significant bacteriuria were then randomly selected for measurement of cardiovascular autonomic reflexes, bladder ultrasound, and mictiography. There were no significant differences between these two groups in age, duration and type of diabetes, glycosylated hemoglobin, blood urea, and creatinine. Abnormalities of cardiovascular autonomic function were more common in the bacteriuric group (P less than .01). Although the bacteriuric group voided a smaller volume of urine, none had evidence of increased residual bladder volume of urine on ultrasound. Diabetic women with cardiovascular autonomic neuropathy appear to be at increased risk of developing bacteriuria. However, age is probably the most important factor influencing the prevalence of bacteriuria in diabetic and in nondiabetic women.

Adolescent↗
PubMedDate not supplied

Effect of glycaemic control, metformin and gliclazide on platelet density and aggregability in recently diagnosed type 2 (non-insulin-dependent) diabetic patients.

Platelet density profiles, intraplatelet nucleotides, intraplatelet beta thromboglobulin (beta TG), plasma beta TG levels, intraplatelet cyclic AMP (cAMP) levels, platelet release reaction, platelet thromboxane (TX)B2 production and plasma fibrinogen levels were investigated in 24 newly diagnosed, non-insulin-dependent diabetic patients and 12 comparable controls. These variables were measured at diagnosis, after a 3-6 week dietary run-in period, and again after 6 months on treatment with either metformin or gliclazide therapy. With dietary restriction of refined carbohydrate and oral hypoglycaemic therapy, there was a reduction in platelet density (p less than 0.05), intraplatelet nucleotides (p less than 0.001), intraplatelet beta TG (p less than 0.001), plasma beta TG (p less than 0.001) and there was an increase in intraplatelet cAMP levels (p less than 0.05). Although these platelet variables returned towards normal, only the platelet density mean returned to within the normal range. There was no significant change in the platelet TXB2 production and plasma fibrinogen levels with treatment. Metformin and gliclazide were equally effective in the glycaemic control of non-insulin-dependent diabetes, and there was no difference between the platelet variables measured in the two groups. We would therefore suggest that improvement of glycaemic control, rather than any specific effect of the oral hypoglycaemic agent employed, is the most important factor in returning these parameters towards normality.

Adenosine Diphosphate↗