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Biomedical subjects

M N Islam

Publications and source records attributed to M N Islam.

At least 109 records · Page 6Linked to original sources
PubMed1985

Self-selectivity problems in interregional and interindustry migration in Canada.

This study is concerned with the role that inter-industry mobility plays in the decision to migrate in Canada, and also with the joint impact on earnings of inter-industry and interregional migration, corrected for selectivity bias. The data, for the period 1970-1971, are from a one percent random sample of a micro data base established by the Unemployment Insurance Commission. "Contrary to the commonly held belief that a migrant's decision to change his location is independent of his decision to change his industry of employment, this paper provides evidence that these movements are in fact interrelated."

Americas↗
PubMed1985

Photoaffinity labelling of the porcine thyrotropin receptor--effect of Graves' immunoglobulin G and anti-TSH anti-idiotypic antibodies.

Despite active investigations, the structure of the thyrotropin (TSH) receptor, its organization and its interaction with putative anti-receptor antibodies remains unknown. We have undertaken photoaffinity cross-linking of TSH-binding sites on porcine thyroid plasma membranes with 125I-bTSH and the photoactive heterobifunctional cross-linker, N-hydroxysuccinimidyl-4-azidobenzoate. In the presence of reductant a single Mr 58,600 band was labelled, whereas 3 distinct bands (Mr 192,400, 86,000 and 59,600) were visualized when photolysed samples were subjected to sodium dodecyl sulphate polyacrylamide gel electrophoresis under non-reducing conditions. The intensities of these labelled bands were quantitatively decreased with increasing concentrations of native bTSH, but not by large amounts of insulin or human chorionic gonadotropin. Graves' disease IgG and an anti-TSH anti-idiotype IgG, both of which are putative anti-receptor antibodies, caused different inhibition patterns on non-reduced gels: anti-TSH anti-idiotype predominantly inhibited the labelling of the Mr 192,400 band (probably the holoreceptor), whereas Graves' IgG also inhibited labelling of lower M.W. bands. Both antibodies had much less influence, of the Mr = 58,600 band resolved in the presence of reductant.

Affinity Labels↗
PubMed1984

Estimation of mean age at first marriage: use of a simple mathematical model.

"The present paper is an attempt to introduce a simple mathematical model to describe the age pattern of proportion never married women. The underlying model was found to give fairly close fit to an observed set of data of some 17 WFS [World Fertility Survey] countries. A mathematical formulation was then suggested in terms of the parameters in the model to estimate the mean age at first marriage. The mean ages obtained under the approach agreed quite closely with those obtained by Hajnal's method. The agreement between the estimates of ever married proportions obtained by the suggested model and...Coale's nuptiality model appeared also to be satisfactory."

Age Distribution↗
PubMed1984

Anti-idiotypic antibodies as probes for hormone-receptor interaction.

On the premise that an antibody combining site is a mirror image of its antigen epitope, it is expected that an anti-idiotypic antibody (i.e., an antibody specific for the combining site of the first antibody) will be homologous to the epitope. Anti-idiotypic antibodies raised against hormones or drugs would, therefore, be anticipated to interact with their respective receptors. According to this schema, anti-idiotypic antibodies could either be antagonists or agonists. Most of the anti-idiotypic antibodies raised against hormones and neurotransmitters to date have proved, however, to be agonists. We have raised antithyrotropin (anti-TSH) anti-idiotypic antibodies and found these to interact with the high affinity binding site for TSH on thyroid plasma membranes and to induce cGMP-dependent adenylate cyclase activation and iodide transport into dispersed thyroid cells, as well as to promote their organization into follicular structures. The anti-TSH anti-idiotypic antibody interacted with a holoreceptor band of relative mass (Mr) approximately 200 000, resolved on sodium dodecyl sulfate-polyacrylamide gel electrophoresis from thyroid membranes and transferred to nitrocellulose paper. In another set of experiments we raised anti-idiotypic antibodies against monoclonal antibodies specific, respectively, for the alpha and beta subunits of TSH. Neither the alpha nor beta monoclonal antibody specific anti-idiotypic antibodies interacted with the TSH holoreceptor. The combinations of the two anti-idiotypic antibodies, however, did so and increased basal cyclase activity significantly compared with normal immunoglobulin G. As a result of the second set of experiments, we propose that the interaction of TSH with its receptor involves two signals delivered by the two subunits rather than a single signal requiring their combination. Anti-idiotypic antibodies raised against highly purified hormones can be obtained in large amounts. They facilitate simple isolation of hormone receptors and are useful as probes for hormone-receptor interactions.

Animals↗
PubMed1984

Hepatitis-B virus infection in Dhaka, Bangladesh.

Three thousand six hundred and ten patients with acute hepatitis in two large hospitals in Dhaka city were tested for HBsAg. Besides, 780 commercial blood donors, 126 doctors and 576 apparently healthy persons were also tested. Passive haemagglutination technique was applied for this test. Patients with post-transfusion hepatitis and doctors with acute hepatitis showed the highest incidence, being 60% and 65.5% respectively. HBsAg was detected only in 15.4% of children and 27.2% of adult patients with acute hepatitis.

Adolescent↗
PubMed1983

Surface labeling of thyrocytes isolated by a new method combining enzymatic digestion and percoll gradient centrifugation.

Thyrocytes were isolated from porcine thyroid glands using a new method entailing two-step collagenase digestion and Percoll gradient centrifugation. Good yield and a high percentage of viable thyrocytes free from other contaminating cells was achieved. Proteins present on the surface of thyroid cell plasma membranes were then specifically labeled using Iodogen and 125I-. Membrane lysates were separated by electrophoresis on 10% polyacrylamide gel, under reducing and nonreducing conditions, followed by autoradiography. When the gels were stained with silver nitrate some 30 bands were visualized in both the presence and absence of reductant. Only 9 bands were found to be labeled under nonreducing conditions and 12 in the presence of reductant. Two bands involved in the thyrotropin receptor structure--Mr = 66,000 and Mr = 70,000, respectively--were visualized in the absence of reductant. Upon reduction the Mr 66,000 band was retained and a new band (Mr = 33,000) was seen. The mild enzymatic treatment used in isolating thyrocytes and the lack of contamination with other cells allowed the consistent labeling of exposed plasma membrane components by the Iodogen method such that the orientation of thyrotropin receptor components in the plasma membrane could be deduced.

Animals↗
PubMed1983

Biological activity of anti-thyrotropin anti-idiotypic antibody.

Rabbit anti-rat anti-human thyrotropin anti-idiotypic antibodies have been raised. These antibodies were active at the thyrotropin (TSH) receptor, in that they inhibited 125I-labeled bovine TSH binding to thyroid plasma membranes, stimulated adenylate cyclase activity through a guanyl nucleotide-dependent mechanism, augmented radioiodide transport into isolated porcine thyroid follicular cells and induced such cultured cells to organize into follicles. Aside from substantiating the expectation that anti-hormone anti-idiotypic antibodies may possess properties of the original hormone, this work raised the possibility that thyroid-stimulating antibodies which cause the hyperthyroidism of Graves' disease may be anti-TSH anti-idiotypic antibodies.

Adenylyl Cyclases↗
PubMed1983

Both TSH and thyroid-stimulating antibody of Graves' disease bind to an Mr 197,000 holoreceptor.

Human and porcine thyroid plasma membranes were submitted to sodium-dodecyl sulphate polyacrylamide gel electrophoresis in the absence and presence of reductant and electrotransferred onto nitrocellulose paper. Native bovine TSH, IgG from all 10 patients with active Graves's disease tested, as well as rabbit anti-bTSH anti-idiotypic antibody were found to bind to a single Mr approximately 197,000 band present only in non-reduced gels. We conclude that TSH and Graves' IgG bind to the TSH holoreceptor.

Animals↗
PubMed1981

Aortocoronary Gore-Tex graft: 18-month patency.

Despite widespread success with Gore-Tex (polytetrafluoroethylene) vascular grafts in peripheral artery operations, very little use has been made of this material in aortocoronary bypasses. We present the case of a 61-year-old woman with a 6-month history of angina who was found to have no suitable saphenous vein available at operation and who therefore underwent Gore-Tex bypass grafting to the right coronary artery. Coronary angiograms made 6 months and 18 months postoperatively showed patency of the 6 mm Gore-Tex replacement graft as well as the internal mammary artery placed to the left anterior descending coronary artery. Although frequent follow-up and close observation are recommended in patients with aortocoronary Gore-Tex grafting, the unique design of this material has made it the best alternative for synthetic coronary bypass conduit in the absence of the saphenous veins, particularly when these veins are found to be inadequate only at the time of operation.

Blood Vessel Prosthesis↗
PubMed1975

The incidence of hepatitis-B-antigen and anti-hepatitis-B among blood donors in Ndola, Zambia.

Hepatitis-B antigen (HBsAG) was detected in the sera of 29 or 250 (11.6%) blood donors in Ndola, Zambia, most of whom were prisoners or students. The incidence among prisoners was 15.1%, among students only 1.6%. Thirteen sera were subtyped, nine carried the y and four the d antigenic determinant. Although there was a marked difference in the incidence of HBs antigen between prisoners and students, when donors were tested for antibody to HBsAg (anti-HBs) this positive. Overall, anti-HBs was detected in 132 of 250 blood donors (52.8%). The sensitivity of radioimmunoassay, counter-immunoelectrophoresis and a newly developed passive haemagglutination (PHA) test, employing tanned formalinised antibody coated turkey erythrocytes, was compared. Although radioimmunoassay provided the most sensitive method, the PHA test compared extremely favourably and was considered to be particularly suitable for use in the tropics.

Adolescent↗