Studies on aspects of autonomic neuropathy in non insulin dependent Diabetes

Autonomic neuropathy (AN) is a well-recognized complication of diabetes mellitus. It has multiple clinical features and is often associated with debilitation and an increased mortality. However, there appears to be a paucity of knowledge with regard to its effects on hormone release and its biochemical sequelae. Recent evidence has accumulated suggesting a role for the autonomic nervous system in regulating release of a number of gastrointestinal hormones. It is therefore possible that autonomic dysfunction may be associated with altered gastrointestinal hormone release and indeed various studies have revealed abnormalities in t he release of these peptides in diabetes mellitus. The prime purpose of this thesis was to provide evidence which might contribute to an understanding of t he interrel a tionship between non insulin dependent diabetes (NIDDM), gastrointestinal hormone release and the autonomic nervous system. Thus studies to evaluate basal and stimulated release of the gastrointestinal hormones gluc a gon (IRG), pancreatic polypeptide (PP), gastrin, gastric inhibitory polypeptide (GIP) and somatostatin (SRIF-LI) have been undertaken in NIDDM. Studies were also carried out to assess whether AN may be implicated in abnormal release of these five gut hormones in diabetes and to determine if one of the hormones, PP, might be used as a marker for AN. Finally the effect of dietary fibre on glucose tolerance was studied to assess whether its effect would be altered in the presence of AN in NIDDM

Amiodarone-induced thyroid dysfunction

Background. Little is known about the frequency of thyroid dysfunction (TD) associated with amiodarone therapy in southern Africa. Objectives. To determine the incidence of TD in a cohort of patients initiated on amiodarone therapy at a cardiac clinic in Cape Town, South Africa, believed to be an iodine-replete area. Patients. Pharmacy records were used to obtain the names of patients who received amiodarone between November 1999 and December 2002. Results. The sample size was 194, but data analysis was limited to the 163 patients for whom there were complete data. The mean age ± standard deviation (SD) was 59.0 ± 15.0 years (range 22 - 89 years). There were 67 female and 96 male patients. The indications for amiodarone therapy were supraventricular tachycardias (N = 102, 62.6%), ventricular tachycardia (N = 55, 33.7%), and prophylaxis against tachycardias (N = 3, 1.8%). The indication was uncertain in 3 patients (1.8%). The median duration of amiodarone treatment was 679.0 days (quartile deviation (QD) 1 172 days, range 3 - 6 425 days) in the whole cohort. The median duration of amiodarone therapy until new TD was 943 days (QD 1 185 days), significantly longer than in patients who remained euthyroid (547 days, QD 1 135 days) (P = 0.05). There were 45 new TD cases (27.6%): 11 patients (6.7%) were thyrotoxic, 1(0.6%) transient thyrotoxicosis, 1 (0.6%) subclinical hyperthyroidism, 13 (8.0%) had subclinical hypothyroidism, 12 (7.4%) hypothyroidism and 7 (4.3%) had minor changes in thyroid function. Conclusions. We found a high incidence of new-onset TD, similar to the highest rates reported internationally. Local factors responsible for this need to be investigated

A 40-year-old woman who developed jaundice during therapy for thyrotoxicosis.

Ekpebegh and Levitt discuss the differential diagnosis of jaundice in patients with thyrotoxicosis

Amiodarone-induced thyroid dysfunction

Background. Little is known about the frequency of thyroid dysfunction (TD) associated with amiodarone therapy in southern Africa. Objectives. To determine the incidence of TD in a cohort of patients initiated on amiodarone therapy at a cardiac clinic in Cape Town, South Africa, believed to be an iodine-replete area. Patients. Pharmacy records were used to obtain the names of patients who received amiodarone between November 1999 and December 2002. Results. The sample size was 194, but data analysis was limited to the 163 patients for whom there were complete data. The mean age ± standard deviation (SD) was 59.0 ± 15.0 years (range 22 - 89 years). There were 67 female and 96 male patients. The indications for amiodarone therapy were supraventricular tachycardias (N = 102, 62.6%), ventricular tachycardia (N = 55, 33.7%), and prophylaxis against tachycardias (N = 3, 1.8%). The indication was uncertain in 3 patients (1.8%). The median duration of amiodarone treatment was 679.0 days (quartile deviation (QD) 1 172 days, range 3 - 6 425 days) in the whole cohort. The median duration of amiodarone therapy until new TD was 943 days (QD 1 185 days), significantly longer than in patients who remained euthyroid (547 days, QD 1 135 days) (P = 0.05). There were 45 new TD cases (27.6%): 11 patients (6.7%) were thyrotoxic, 1(0.6%) transient thyrotoxicosis, 1 (0.6%) subclinical hyperthyroidism, 13 (8.0%) had subclinical hypothyroidism, 12 (7.4%) hypothyroidism and 7 (4.3%) had minor changes in thyroid function. Conclusions. We found a high incidence of new-onset TD, similar to the highest rates reported internationally. Local factors responsible for this need to be investigated. JEMDSA Vol.10(1) 2005: 6-

Differential effects of abdominal adipose tissue distribution on insulin sensitivity in black and white South African women

Black South African women are more insulin resistant than BMI-matched white women. The objective of the study was to characterize the determinants of insulin sensitivity in black and white South African women matched for BMI. A total of 57 normal-weight (BMI 18–25kg/m2 ) and obese (BMI > 30kg/m2 ) black and white premenopausal South African women underwent the following measurements: body composition (dual-energy X-ray absorptiometry), body fat distribution (computerized tomography (CT)), insulin sensitivity (SI , frequently sampled intravenous glucose tolerance test), dietary intake (food frequency questionnaire), physical activity (Global Physical Activity Questionnaire), and socioeconomic status (SES, demographic questionnaire). Black women were less insulin sensitive (4.4 ± 0.8 vs. 9.5 ± 0.8 and 3.0 ± 0.8 vs. 6.0 ± 0.8 × 10−5/min/(pmol/l), for normal-weight and obese women, respectively, P < 0.001), but had less visceral adipose tissue (VAT) (P = 0.051), more abdominal superficial subcutaneous adipose tissue (SAT) (P = 0.003), lower SES (P < 0.001), and higher dietary fat intake (P = 0.001) than white women matched for BMI. SI correlated with deep and superficial SAT in both black (R = −0.594, P = 0.002 and R = 0.495, P = 0.012) and white women (R = −0.554, P = 0.005 and R = −0.546, P = 0.004), but with VAT in white women only (R = −0.534, P = 0.005). In conclusion, body fat distribution is differentially associated with insulin sensitivity in black and white women. Therefore, the different abdominal fat depots may have varying metabolic consequences in women of different ethnic origin