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Biomedical subjects

M G Hammond

Publications and source records attributed to M G Hammond.

At least 19 recordsLinked to original sources
PubMed2001

HLA class II antigens in South African Blacks with type I diabetes.

Type 1 diabetes mellitus is poorly characterised in many African communities, including South Africa, where little is known of the disease epidemiology. This study aimed to identify the HLA class II alleles associated with type 1 diabetes in a group of Zulu subjects in Durban, KwaZulu-Natal by PCR-SSP. The HLA alleles associated with type 1 diabetes included HLA-DQB*0302 (P<0.0001), DRB1*O9 (P<0.0001), DRB1*04 (P=0.002), DRB1*0301 (P=0.003), DQB*02 (P=0.004) and DQA*03 (P=0.035). Estimated haplotypes positively associated with type 1 diabetes included HLA-DRB1 *0301-DQA*0501, DRB1*04-DQA*03, DRB1*04-DQB*0302, DRB1*0301-DQB*0201, DQA*0501-DQB*0201 and DQA*03-DQB*0302. These findings are similar to those reported from Zimbabwe and other populations with type 1 diabetes.

Adult↗
PubMed2001

Pemphigus in South Africa.

BACKGROUND: Pemphigus is an autoimmune disease characterized by intraepidermal blistering. We describe the demography, prevalence, clinical features, response to treatment, and human leukocyte antigen (HLA) characteristics of pemphigus in Kwa-Zulu Natal, South Africa. METHODS: All patients with pemphigus were prospectively recruited over 12 years from January 1987 to December 1999. The demography, clinical features, histology, and immunofluorescence (IF) were recorded. In a subset of patients, HLA tests were performed. RESULTS: One hundred and twelve patients had pemphigus. Pemphigus foliaceus (PF) was the commonest variant seen (62 patients) and 80% of these patients were black. The mean age was 43 years (12-93 years) and the male to female ratio was 1 : 1.4. Fifty patients had pemphigus vulgaris (PV), of whom 82% were Indian. The mean age of presentation of PV was 48 years (21-82 years). The male to female ratio was 1 : 1.7. There was no mucosal involvement in PF. PV patients had painful oral lesions. The mortality rate was 14% in the total sample (six in PV and two in PF). HLA-B8 was positive in 41% of patients with PF (P < 0.001). CONCLUSIONS: PF occurs more commonly in black people, while most cases in Indians present with the PV subtype. Pemphigus patients present with severe and extensive disease, and PV patients share features in common with patients from their land of origin (India), suggesting a genetic link.

Adult↗
PubMed1998

HLA-A, -B, -DR and -DQ antigens in black patients with infective endocarditis.

In order to determine if genetically determined immune response factors could play a role in the pathogenesis of infective endocarditis in black patients, we performed HLA-A and HLA-B typing in 38 patients with this disease and HLA-DR and HLA-DQ typing in 33 and 27 of these individuals, respectively. HLA typing was also carried out in a control group of normal black adults. The HLA typing was done by means of a standard microlymphocytotoxicity test. No difference in HLA-A, HLA-B, HLA-DR and HLA-DQ antigen frequencies between patients and controls were noted. This study did not provide any evidence that genetic factors could contribute to a disposition to infective endocarditis.

Adolescent↗
PubMed1997

HLA-A, B, DR, and DQ antigens in Indian patients with severe chronic rheumatic heart disease.

To determine whether genetic factors could be involved in the pathogenesis of rheumatic heart disease, we performed HLA-A and HLA-B typing in 59 Indian patients with severe chronic rheumatic heart disease requiring cardiac surgery, and HLA-DR and HLA-DQ typing in 58 of these patients. The HLA typing was done by a standard microlymphocytotoxicity method. Patients were 12 to 59 years old (mean 32.9 years). No significant differences in HLA-A, HLA-B, HLA-DR and HLA-DQ frequencies between patients and controls were noted. The role of genetically determined immune-response factors in the pathogenesis of chronic rheumatic heart disease was not evident in this study.

Adult↗
PubMed1997

HLA-antigens in black patients with hepatocellular carcinoma.

To determine whether genetically determined immune response factors could be involved in the pathogenesis of hepatocellular carcinoma, we performed HLA-A and HLA-B typing in 55 black patients with histologically-proven hepatocellular carcinoma, and HLA-DR and HLA-DQ typing in 47 of these patients. The HLA typing was also carried out in a control group of normal black patients. The HLA typing was done by a standard microlymphocytotoxicity method. No difference in HLA-A, HLA-DR and HLA-DQ frequencies between patients and controls were noted. HLA-B21 was present in 10.9% of patients compared to 1.8% of control subjects (corrected p < 0.005; relative risk = 6.6) and HLA-B49 was present in 7.3% of patients compared with 1.1% of normal control subjects (corrected p < 0.007; relative risk = 7.1). These findings suggest that genetic factors may play a role in the pathogenesis of hepatocellular carcinoma.

Adult↗
PubMed1994

Differences in HLA-DR association with rheumatoid arthritis among migrant Indian communities in South Africa.

Previous surveys among Indians with RA have shown a significant association with HLA DR4 in North India and with HLA DR1 in the UK. We studied a migrant Indian population in South Africa to determine their genetic associations with RA. A group of 121 unrelated RA patients from three communities (Hindi, Muslims and Tamils) were studied. The Muslims showed a significant association with DR4 but the Hindi and Tamils showed a significant association with DR10. This survey shows that the Indian community is a heterogenous group regarding their HLA associations with RA and different associations are noted in the various communities.

Adult↗
PubMed1994

HLA-antigens in oral submucous fibrosis.

HLA-typing was carried out on 122 areca nut chewers who attended hospitals for complaints unrelated to the habit. The subjects were South Africans of Indian extraction. The study did not include haplotypes. Palpable fibrous bands in the mouth indicated oral submucous fibrosis. The subjects were divided into 4 groups based on specific oral symptoms and signs. Groups A and B were without fibrous bands. Group A (47 subjects) included those with one or no symptoms while group B (28 subjects) suffered from 2 to 7 oral symptoms. Group C (17 subjects) had oral symptoms and represented early or mild oral submucous fibrosis and exhibited at least one discrete palpable fibrous band. Group D (30 subjects) were classic oral submucous fibrosis cases with multiple bands. The high occurrence of oral submucous fibrosis in this study group (39%) is similar to the occurrence in comparable age groups reported earlier in South Africa and is conceivably due to the higher age range of the subjects and their relatively long exposure to the areca nut. We were unable to demonstrate a specific pattern of HLA-antigen frequencies in chewers with or without the disease. Furthermore, there were no differences between the study population and the controls. It is concluded that there is not necessarily a HLA-associated susceptibility in oral submucous fibrosis.

Areca↗
PubMed1994

Gout in black South Africans: a clinical and genetic study.

OBJECTIVE: To define the clinical characteristics of gout and determine if there were any genetic associations with gout in black South Africans. METHODS: The records of 107 patients with gout seen over a five year period were retrospectively analysed. The HLA class I and class II antigens were studied in a prospective survey of 46 patients. RESULTS: The male to female ratio was 6.6:1. The diagnosis of gout was based on identification of monosodium urate crystals from the synovial fluid, synovial tissue or tophaceous material in 62 patients (58%) and on clinical criteria in the remaining 45 patients (42%). The mode of presentation was monoarthritis in 40 patients (37.4%), pauciarthritis in 30 (28%) and polyarthritis in 37 (34.6%). The joints which were most frequently involved were the knee in 91 patients (85%), the first metatarsophalangeal in 80 (74.8%) and the ankle in 66 (61.7%). A secondary cause was identified in 52 patients (48.6%) (diuretic therapy in 48 patients and chronic renal impairment in four); 55 patients (51.4%) had primary gout. The genetic study showed an increased frequency of HLA-B14 in patients with primary gout compared with controls. CONCLUSIONS: Gout is more common in black Africans than previously recognised and frequently presents with involvement of more than one joint. There was an increased frequency of HLA-B14 in patients with primary gout but the clinical significance of this is uncertain.

Adult↗
PubMed1993

The effect of growth factors on the proliferation of human endometrial stromal cells in culture.

OBJECTIVE: Development of ectopic implants of endometriosis is associated with both an inflammatory response by macrophages and endometrial stromal cell proliferation. Macrophages are capable of releasing a variety of inflammatory mediators, including growth factors. To assess the impact of such factors on endometrial tissue, we have studied the effects of recombinant growth factors, fibroblast growth factor, epidermal growth factor, transforming growth factor-alpha, and inflammation mediators transforming growth factor-beta, and tumor necrosis factor-alpha on human endometrial stromal cell proliferation. STUDY DESIGN: Increasing concentrations of these compounds were added to cultures of primary, secondary, and long-term stromal cells and the cells were harvested at 24, 48, and 72 hours. RESULTS: Epidermal growth factor, transforming growth factor-alpha, transforming growth factor-beta, and fibroblast growth factor induced a statistically significant, dose-dependent increase in stromal cell thymidine uptake of 1.5- to fivefold. The cytokine tumor necrosis factor had no effect alone, but the combination of fibroblast growth factor and tumor necrosis factor had a synergistic effect, increasing cell proliferation 25% to 84% over fibroblast growth factor alone. CONCLUSION: The stromal cell response to a wide range of cell growth effectors and the potential of mediators like tumor necrosis factor-alpha to synergize suggest that such macrophage-secretory products may contribute to proliferation of endometrial implants in vivo.

Cell Division↗
PubMed1992

The effect of laparoscopic ablation or danocrine on pregnancy rates in patients with stage I or II endometriosis undergoing donor insemination.

The effect of treatment on stages I and II endometriosis was evaluated in 61 women with laparoscopically proven disease who were undergoing therapeutic donor insemination. Only treatment cycles completed after diagnostic laparoscopy were used for analysis. To evaluate fecundity, we performed life-table analysis on 343 treatment cycles of therapeutic donor insemination in 67 patients with stage I or II endometriosis and compared it with 212 cycles in 43 patients with no female infertility factors. Average monthly fecundity and cumulative conception rates over six cycles were calculated for each group. A significant difference was found when patients with laparoscopically proven normal anatomy were compared with those with endometriosis (P = .002). The fecundity did not differ significantly between stage I and stage II endometriosis (P greater than .05). Neither ablation during laparoscopy nor medical treatment with danocrine improved the fecundity of patients with early-stage endometriosis (P greater than .05).

Adult↗
PubMed1992

Abnormal findings on hysterosalpingography: effects on fecundity in a donor insemination program using frozen semen.

OBJECTIVE: We sought to evaluate the effect of abnormal baseline hysterosalpingography (HSG) on subsequent fecundity during the first six cycles of treatment. METHODS: Hysterosalpingography was performed on 208 asymptomatic ovulatory women with no history of pelvic disease who were referred for donor insemination. The findings were categorized into five groups: 1) normal study, 2) uterine anomaly or filling defect with bilateral tubal patency, 3) normal uterine anatomy with unilateral tubal patency, 4) normal uterine anatomy with bilateral tubal blockage, and 5) normal uterine anatomy with hydrosalpinx. Subjects in groups 4 and 5 received inseminations only if patency of at least one fallopian tube was demonstrated with laparoscopy. Life-table analysis was performed to calculate the average monthly fecundity and cumulative conception rates for each group. The Mantel-Haenszel test was used to compare group fecundities. RESULTS: A total of 1460 donor insemination cycles were performed. The number of cycles in each group were as follows: group 1, 1173 (80%); group 2, 153 (10%); group 3, 90 (6.2%); group 4, 16 (1.1%); and group 5, 28 (1.9%). None of the patients in group 4 or 5 conceived. The cumulative conception rates in the first three groups were 46, 34, and 40%, respectively, and were not significantly different from one another (P greater than .05). Although a high incidence of uterine filling defects and unilateral tubal blockage was observed (19.2%), the incidence of an abnormal HSG finding that significantly decreased fecundity was only 2.8%. CONCLUSION: In women with no history of tubal or uterine disease, routine HSG before initiation of donor insemination is of limited value for identifying decreased treatment fecundity.

Adult↗
PubMed1991

Fertility rates in men with normal semen characteristics: spermatozoal testing by induction of the acrosome reaction and Wright-Giemsa staining for subtle abnormal forms.

Little is known about the fertility potential of semen from men who fulfill the accepted criteria of normal semen quality. We examined retrospectively the fertility rates of semen donors with normal semen quality. Donor performance was evaluated in women who had no known infertility factors or had only ovulatory dysfunction corrected by clomiphene. Cycles of therapeutic donor insemination were monitored for ovulation, and pregnancy outcome was followed up. Pregnancy resulted from therapeutic donor insemination with 21 donors and did not result in pregnancy with five (the range of the percentage of cycles in which pregnancy occurred was zero to 31). The comparison of donor semen analysis characteristics with pregnancy rates indicated that the total number of motile spermatozoa per ejaculate correlated with pregnancy rate (P = .04). Cox proportional hazard regression analysis showed that when the value for percentage of abnormal forms was combined with the total number of motile spermatozoa, a significant negative association was found between abnormal forms and conception (P = .04). Experiments comparing semen from high-fertility donors (top quartile of pregnancy rate) and low-fertility donors (lowest quartile) demonstrated a greater proportion of spermatozoa with inducible acrosome reactions in the high-fertility group (P less than .05). A Wright-Giemsa stain used to detect subtle abnormal forms in spermatozoa did not discriminate between the groups. These data suggest that differences in fertility potential exist among donors, even though all may exceed the accepted criteria for normal semen quality. Differences in the ability of spermatozoa to capacitate or undergo the acrosome reaction may be a mechanism for diminished fertility in donors with normal semen characteristics.

Acrosome↗
PubMed1991

The effect of age on female fecundity.

To determine the relationship between age and female fecundity, 210 women were studied prospectively. The subjects had negative infertility evaluations and were receiving therapeutic donor insemination. Life-table analysis was performed on 751 donor insemination cycles. For comparison, patients were divided into five separate age groups and into two separate groups, ages 19-34 and 35-45. Monthly fecundity and cumulative conception rates were calculated for each group. A significant difference was found when all age groups were compared (P = .05) and when those at or above age 35 and those below age 35 were compared (P less than .05). Frozen semen was used in 92% of all cycles. The average monthly fecundity of all patients treated with frozen semen was 16%. This study confirms a progressive decline in fecundity with age in a completely evaluated group of women undergoing therapeutic donor insemination and demonstrates that frozen semen can yield acceptable fecundity provided sufficient numbers of motile sperm are used for each procedure.

Adult↗
PubMed1990

HLA class I and II antigens in South African blacks with Graves' disease.

A study was done to evaluate the relationship between Graves' disease and the HLA system in South African Blacks of Zulu descent. One hundred and three patients with Graves' disease and 1416 control subjects were typed for HLA A, B, and C antigens while HLA DR antigens were done on 63 of the former and 330 of the latter. There was a significant increase in the frequency of HLA DR3 in patients compared to control subjects (57.1% vs 36.1%; P corrected = 0.014). A relationship was also seen at the DR1 locus (14.3% vs 4.6%; P corrected = 0.023).

Black People↗