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Biomedical subjects

M Christy

Publications and source records attributed to M Christy.

At least 37 records · Page 2Linked to original sources
PubMed1981

A review of HLA antigens in longstanding IDDM with and without severe retinopathy.

The hitherto published studies of HLA antigens in diabetic retinopathy are reviewed. The existence of HLA associated genes conferring susceptibility (or resistance) to the development of diabetic retinopathy has neither been proved nor ruled out. Possible explanations of the lack of unanimous conclusions are discussed. Further studies in caucasians and other ethnic groups are warranted: future studies should be internationally accepted, well-defined diagnostic criteria and classifications of diabetes and diabetic retinopathy, and study and control groups should be carefully matched for other genetic and nongenetic risk factors. Future studies should include HLA D/DR typing.

Diabetes Mellitus↗
PubMed1980

Direct streptozotocin toxicity on dispersed mouse islet cells determined by [51]Cr-release.

Dispersed islet cells were prepared from collagenase-isolated lean mouse pancreatic islets by Dispase-II and subsequent mechanical treatment in calcium depleted media. An average yield of 600 cells per islet was obtained, 84% of the cells being beta-cells. Cells were incubated with radioactive chromium as a marker of cell viability. Optimal labelling of 1--2 cpm per cell was obtained by incubating 10(5) cells with 10(6) cpm of [51]Cr for 90 min. When islet cells were incubated with streptozotocin, this drug induced [51]Cr-release after a lag time of 2--4 hours. Furthermore, a positive correlation between streptozotocin concentrations and [51]Cr-release was found. This assay of cytotoxicity was highly reproducible and might be applicable in the study of other beta-cell damaging agents or autoimmune phenomena in the pathogenesis of diabetes.

Animals↗
PubMed1979

HLA studies in diabetics.

The studies of HLA in diabetes mellitus have strongly supported the subdivision into (at least) two genetically distinct groups: The juvenile onset (or perhaps better the insulin dependent) type DM, which shows a marked association to the HLA system, and the maturity onset type with a weak or no association to HLA. The HLA system has provided tools to test specific genetic models for the insulin dependent DM. A model involving one disease susceptibility locus closely linked to the HLA-loci and with a recessive susceptibility allele in linkage disequilibrium with some of the HLA factors has been proposed by others. This model cannot be totally rejected on the basis of the available data, but it is made less likely, especially because it leads to very low estimates of the penetrance which is discrepant from independent estimates, based both on studies on monozygotic twins and other families. In addition suggestive but not yet conclusive evidence of an excessive risk for HLA-Dw3/Dw4 heterozygotes is in conflict with this model.

Diabetes Mellitus↗
PubMed1979

Incidence of insulin-dependent diabetes mellitus (0--29 years at onset) in Denmark.

Incidence data from Denmark on the insulin-dependent diabetes mellitus in the age group 0--29 years have been collected in two different geographical areas (West and South Jutland plus Copenhagen and North Zealand). An incidence of 13.3 per 100,000 per year (range 12.5--13.6) was registered (N = 792). No difference was found between the two areas. The male incidence exceeded the female incidence by 25.4 per cent. The age distribution showed rising values until a peak in the early puberty with a decline until a rather constant level after puberty. From year to year a seasonal variation of onset was demonstrable with maximum in the winter and minimum in the summer for males only. Ascertainment was found to be between 87.7 and 98.6 per cent and the annual number of new insulin-dependent diabetics in Denmark in the age group 0--29 years can be calculated to 310-350.

Adolescent↗
PubMed1979

Subclinical hypothyroidism in Addison's disease.

Fourteen patients with Idiopathic Addison's disease (IAD) were studied in order to detect a possible subclinical hypothyroid state. All were clinically euthyroid with normal serum thyroxine (T4) and serum 3,5',5'-triiodothyronine (T3). Eleven had circulating thyroid microsomal antibodies in blood. The mean basal serum TSH was significantly higher than that of the control group but only three patients had values above the upper normal range. The mean value of serum T4 was decreased as compared to that of the normal persons, while serum 3,3',5'-triiodothyronine was elevated. 7.5 mU bovine thyrotrophin per kilogram body weight injected intravenously caused a rise in serum T3 not different from the response in normals. However, as well increasing serum TSH as increasing microsomal antibody titer correlated significantly to decreasing thyroidal release of T3. Our results suggest that clinically euthyroid patients suffering from IAD might have a beginning thyroidal insufficiency because of a progressive immunological damage of the thyroid.

Addison Disease↗
PubMed1979

HLA and insulin-dependent diabetes mellitus.

As suggested from clinical data and on the basis of human leukocyte antigen (HLA) data, insulin-dependent diabetes mellitus (IDDM) is a disease entity in itself and is different from non-insulin-dependent diabetes and other types of diabetes mellitus in aetiology and pathogenesis. HLA-B8 is associated with IDDM in all Caucasian populations studied, irrespective of the age of onset of the disease. HLA-B15 is associated with IDDM in populations of Northern European and British origin, while B18 seems to replace B15 in Southern European populations. IDDM is uncommon in populations where the HLA-B8 frequency is low, and in the Japanese IDDM occurs in association with Bw22. The HLA-Dw3 and Dw4 association with IDDM is stronger than that of the B alleles. Relative risks for B8 and B15 heterozygous and homozygous individuals are identical, i.e., no gene-dose effect exists. The relative risk of B8/B15 carriers is double that of relative risks of B8 and B15 alone, i.e., there are two IDDM-associated genes. The same applies to Dw3/Dw4 carriers. In families the phenotype IDDM segregates with a certain genotype, the diabetic proband's HLA haplotype. Only a small proportion of family members carrying the 'diabetic haplotype' develop IDDM.

Autoimmune Diseases↗
PubMed1977

Incidence, seasonal and geographical patterns of juvenile-onset insulin-dependent diabetes mellitus in Denmark.

The incidence, sex, seasonal and geographical patterns of juvenile-onset insulin-dependent diabetes mellitus (j.i.d.m.) were studied retrospectively on one third of the Danish population 1970-1974. The j.i.d.m. incidence remained fairly constant during the study period, the average being 13.2 per 100000 per year. The total number of boys exceeded the number of girls by 27%. A marked peak of incidence was found at 12-14 years, earlier for females than for males. A seasonal variation in onset (diagnosis) of j.i.d.m. was observed with the lowest number of new cases in May-July. The j.i.d.m. incidence seemed to show socioeconomic differences, being highest in those parts of the survey area with lower status.

Adolescent↗