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Biomedical subjects

M A Omar

Publications and source records attributed to M A Omar.

At least 73 records · Page 4Linked to original sources

The insulin and glucose response to an oral glucose load in non-insulin-dependent diabetes in the young. A study of 4 families.

Four Indian families with three-generation transmission of non-insulin-dependent diabetes were studied. Only 30% of the siblings were diabetic. The mean age of onset of diabetes was 20,1 years; 25% of the diabetics were obese, while all non-diabetic family members were of normal weight. All consenting living family members (12 diabetics and 16 non-diabetics) were subjected to an oral glucose tolerance test. After glucose administration, the 12 diabetics displayed a delayed and attenuated insulinaemic response. The area under the insulin curve and the insulin-glucose ratio were lower in the diabetics.

Adolescent↗

Islet cell antibodies and other autoantibodies in South African blacks and indians with insulin dependent diabetes mellitus (IDDM).

The presence or absence of islet cell antibodies and other autoantibodies was determined in 47 African and 34 Indian patients with IDDM and 37 controls. Islet cell antibodies (ICA-IgG) were found in over a third of the patients and in only 2 controls. Complement fixing antibodies (ICA-Cf) were found in 10% of patients, but in none of the controls. Persistence of ICA beyond 3 years was more frequent in Black compared to Indian patients. Parietal cell antibodies were found more often in patients (20%) than controls (5%) as were thyroid microsomal antibodies (11% vs. 0%). None of the patients or controls had adrenal antibodies.

Adolescent↗

Antibodies to the thyroid gland and to the thyrotrophin receptor in African and Indian thyrotoxic patients.

Sixty two thyrotoxic patients, 34 African and 28 Indian, were studied in order to assess the prevalence of thyroid antibodies and TSH binding inhibitory activity (TBI): 45 had Graves' disease and 17 had toxic nodular goitres. Microsomal and thyroglobulin antibodies were positive more often in Indian than in African patients with Graves' disease (microsomal 52% vs 37.4%, P less than 0.05; thyroglobulin 38.1% vs 4.2%, P less than 0.001). Patients with toxic nodular goitres had a lower prevalence of positive microsomal antibodies (P less than 0.01), but not of thyroglobulin antibodies (P = 0.1) when compared with patients with Graves' disease. TBI activity measured by a radioreceptor assay was positive in 43 of the 45 (95%) patients with Graves' disease and only 1 of the 17 patients (5.9%) with toxic nodular goitre. It thus appears that TBI activity is a sensitive marker in the diagnosis of Graves' disease and that there is a lower prevalence of thyroglobulin and microsomal antibodies in African patients compared with Indian patients.

Africa↗

Prolactin secretion in Sheehan's syndrome. Responses to thyrotropin-releasing hormone and metoclopramide.

The prolactin response to thyrotropin-releasing hormone (TRH) and metoclopramide was studied in 16 patients with Sheehan's syndrome and 16 matched controls in the follicular phase. Metoclopramide resulted in a greater prolactin response than TRH did in the controls. However, both stimuli failed to evoke any appreciable prolactin response in the patients with Sheehan's syndrome. Since metoclopramide is generally free of side effects and far cheaper than TRH, we recommend the prolactin response to metoclopramide as the preferred screening test in the diagnosis of Sheehan's syndrome.

Adult↗

Pituitary tumours in African and Indian patients.

Over a five year period 55 patients with pituitary tumours (35 African and 20 Indian patients) were seen at the Endocrine Unit, King Edward VIII Hospital. Of the 33 patients with secretory tumours 20 had GH-secreting tumours (acromegaly), 8 prolactinomas and 5 ACTH-producing tumours (Cushing's disease); in addition 4 of the patients with acromegaly probably had combined GH and prolactin secreting tumours. The group with non-secretory tumours comprised 13 patients with craniopharyngioma, 7 with chromophobe adenomas and 2 patients with parasellar tumours. The majority of patients with non-secretory tumours were of African descent. Hormonal deficiencies present in the patients tested, were as follows: GH deficiency 73.3%; hypocorticolism 66.7%; hypogonadism 35.9% and hypothyroidism 14%. It thus appears that the patients in the present study differ from populations studied elsewhere with respect to the relative frequency of the various secretory tumours and the prevalence of certain hormonal deficiencies.

Acromegaly↗

The spectrum of non-insulin-dependent diabetes in the young in a migrant Indian population.

The familial aggregation and degree of adiposity of 108 Indian patients with non-insulin-dependent diabetes in the young was studied. All patients had onset of diabetes under 30 yr and the female to male ratio was 5:1. Obesity as defined was present in 52 patients (48.2%). A positive family history of diabetes was present in 90 patients (83.3%). Two distinct subtypes emerged in the patients with a positive family history; the offspring of conjugal diabetic parents (29%) and maturity onset diabetes of the young (MODY) with 3-generation transmission (13%). In conclusion, the syndrome of NIDDY in Indians comprises at least 3 subtypes: offspring of conjugal diabetic parents, MODY and patients without a family history (sporadic type).

Adolescent↗

Microvascular complications and non-insulin-dependent diabetes of the young in South African Indians.

103 Indians (74 females, 29 males) with NIDDM diagnosed before age 30 yr on the basis of the revised WHO diagnostic criteria were studied in order to assess the prevalence of microvascular complications. The mean duration of NIDDM in the subjects was 11 yr (range 2-38 yr). 24 patients (23%) eventually required insulin therapy for control after a mean interval of 11.8 yr (range 5-38 yr). Diabetic retinopathy was present in 37 patients (35.9%), of whom 6 had proliferative retinopathy. Nephropathy was found in 16 patients (15.5%). The mean GFR of these patients was 46.8 ml/min, compared to a mean of 97.1 ml/min in 12 of the patients without nephropathy who had a similar mean duration of disease. The mean duration of disease in patients with retinopathy and nephropathy was 14.9 yr and 14.8 yr respectively. In the patients who eventually required insulin therapy both retinopathy (75%) and nephropathy (41%) were more common but the mean duration of disease in these patients was longer (16 yr vs 9 yr). This study has underlined the heterogeneity of NIDDM in the young, as microvascular complications are by no means uncommon in South African Indians with the disease.

Adolescent↗

The prevalence of diabetes mellitus in a large group of South African Indians.

The prevalences of diabetes mellitus and impaired glucose tolerance (IGT) among 866 Indians living in the Chatsworth area of Durban were determined. The study group was selected by cluster sampling and the participants underwent a modified glucose tolerance test (GTT) (determination of fasting and 2-hour plasma glucose levels after a 75 g glucose load). On the basis of the revised World Health Organization criteria the overall prevalence of diabetes mellitus was 11% and of IGT 5,8%. Of the 368 men, 7,6% were found to have diabetes mellitus and 7,1% IGT; the prevalence of diabetes mellitus was much greater among women (13,5%), while there was less IGT (4,8%). Subjects with diabetes mellitus were significantly older (mean 50,7 years) than those with a normal GTT (mean 30,9 years), but of similar age distribution compared with the IGT group (mean 46 years). Subjects with a normal GTT had a significantly lower mean body mass index (22,1 +/- 2,8) compared with diabetic subjects (26,1 +/- 5,2) or the IGT group (25,8 +/- 6,6). Obesity was commonly associated with both diabetes mellitus and IGT, particularly among women.

Adolescent↗

HLA antigens and non-insulin-dependent diabetes mellitus in young South African Indians.

HLA, A, B and C antigens were determined in 84 South African Indian patients with non-insulin-dependent diabetes mellitus (NIDDM) in whom age of onset was under 35 years and in 760 healthy Indian controls. Increased frequencies of Aw24, B15 and Bw61 were seen in the patients, but the corrected P value was not significant. Among Indians of North Indian origin, however, there was a significant association between B15 and NIDDM (corrected P less than 0,012; relative risk 4,8). In Indians of South Indian origin no clear association with any specific HLA antigens was seen, although there was a slight increase in the frequency of Aw24 (uncorrected P less than 0,007; corrected P greater than 0,05). The findings in this study serve to emphasize the heterogeneity of diabetes mellitus, since no association between NIDDM and HLA antigens has been noted in whites.

Adult↗

Assay for islet cell antibodies. Protein A--monoclonal antibody method.

Assays for islet cell antibodies (ICA) are finding increasing application in clinical diabetology. We have developed a new islet cell antibody assay system (ICA-pA), whose salient features include: (1) utilization of fluorescein-conjugated staphylococcal protein A as a standard second-step reagent, the advantages of this approach being improved "signal" (islet)/"noise" (acini) ratio due to reduction of interfering background acinar pancreatic staining, and facilitation of assay standardization provided by the use of a chemically pure conjugated protein A reagent; (2) monoclonal antibody counterstaining with rhodamine-conjugated BISL-32 for the rapid identification of islets in pancreatic sections; and (3) quantitation of circulating serum ICA by microimmunofluorometric techniques.

Antibodies, Monoclonal↗

HLA A, B, C and DR antigens in young South African Indians with insulin-dependent diabetes mellitus.

The HLA status of South African Indian insulin-dependent diabetic patients in whom the age of onset of diabetes was under 35 years was compared with that of a group of healthy Indian controls. HLA A, B and C antigens were determined in 68 patients and 760 controls, while DR specificities were determined in 35 patients and 235 controls. The diabetic patients showed a significant increase in the frequencies of HLA B8 (19,1% v. 6,8%; relative risk 3,2; corrected P less than 0,04) and Aw24 (42,6% v. 26,8%; relative risk 2,2; corrected P less than 0,04) antigens compared with controls. HLA DR3 was found to be much more common in patients than in controls (31,4% v. 12,8%; relative risk 3,1; corrected P less than 0,035), but DR3/DR4 heterozygosity was associated with a much greater relative risk (7,25). Among patients of North Indian origin a strong association with DR4 was seen (45,5% v. 9,1% (controls); relative risk 8,3).

Diabetes Mellitus, Type 1↗

C-peptide response to a glucose load in young blacks and Indians with insulin-dependent diabetes mellitus.

Residual beta cell function based on C-peptide assays was estimated in 39 patients (27 Blacks, 12 Indians) with insulin-dependent diabetes mellitus and 18 controls (9 Blacks, 9 Indians) using glucose as a stimulus. The diabetic patients showed significantly lower maximal C-peptide values (mean 0,53 +/- 0,08 nmol/l) and delayed peak levels (mean 137 minutes after ingestion of glucose) compared with the controls (mean 2,15 +/- 0,31 nmol/l and 54 minutes respectively). Just over 20% of the patients had no residual beta cell function, this conclusion being made on the basis of undetectable basal C-peptide levels which failed to rise after glucose stimulation. A significant correlation was seen between glycosylated haemoglobin levels and maximal C-peptide levels (r = 0,45, P less than 0,01). C-peptide levels tended to be lower in Black than in Indian patients, but the difference was not significant.

Adolescent↗

Complications of early-onset insulin-dependent diabetes mellitus in Blacks and Indians.

Blacks and Indians with early-onset insulin-dependent diabetes mellitus (IDDM) were studied in order to assess the prevalence of acute and chronic complications. Of the 92 Blacks almost 70% developed ketoacidotic coma on one or more occasions, whereas 50% of the 41 Indians manifested this complication. Most of the chronic complications were related to duration of IDDM. Retinopathy was found in 14% of the Black and 22% of the Indian patients, nephropathy in 3% and 7% and neuropathy in 22% and 32% respectively. Compared with findings in other studies, IDDM in these population groups is not associated with a particularly high prevalence of chronic complications.

Adult↗