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Biomedical subjects

H Khan

Publications and source records attributed to H Khan.

At least 73 records · Page 4Linked to original sources
PubMed1991

A comparison of two populations of decidual cells by immunocytochemistry and prostaglandin production.

The decidua has been implicated in the control of human labour, particularly through changes in prostaglandin production, but this tissue contains a number of different cell types. A density gradient system was used to obtain two populations of cells from term human decidua, and these populations were characterised. The more dense cells (population B) was a mixed population, predominantly macrophages (80%), but small numbers of T- and B-lymphocytes were also present, as identified by immunocytochemistry. Most of these cell types also contained detectable levels of cyclooxygenase enzyme. The less-dense cell population (population A) did not contain significant numbers of the above cell types and released prolactin, suggesting that they were decidual stromal cells. This preparation of decidual stromal cells may be of use in defining the functions of these cells in labour.

Antibodies, Monoclonal↗
PubMed1991

Calcitonin gene-related peptide and substance P decrease in the rabbit colon during colitis. A time study.

The sensory neuropeptides, substance P and calcitonin gene-related peptide, have been implicated in inflammatory reactions in several tissues. An immune-complex model of colitis was used in rabbits to determine the colonic content (nmol/g protein) of immunoreactive substance P and calcitonin gene-related peptide at various times after induction of inflammation to assess changes in these neuropeptides during the inflammatory response. Calcitonin gene-related peptide content was decreased by 66% 4 hours after induction of inflammation and reached a maximum of 80% at 48 hours. The substance P content was decreased at 8 hours, with a maximum decrease of 64% at 48 hours. Substance P decrease was detected in the muscle layer. The amounts of substance P in the mucosal/submucosal layer extracts were too low to allow accurate measurements. Calcitonin gene-related peptide decreased both in the muscle and the mucosal-submucosal layers. Immunohistochemical analysis showed that calcitonin gene-related peptide and substance P innervation patterns were comparable in normal and inflamed colon, even though there appeared to be a decrease in density and intensity of the staining, particularly for calcitonin gene-related peptide at 48 hours. The early decrease of calcitonin gene-related peptide and substance P during the time course of colitis might be due to release from nerve terminals of the gut during the inflammatory response. The profound changes in colonic calcitonin gene-related peptide and substance P content during colitis may have important implications during inflammation and subsequent tissue repair and may also lead to disturbances in gut motility.

Animals↗
PubMed1991

Quantitative production of prostaglandin E2 and its metabolites by human fetal membranes.

Cultured amnion, choriodecidua and intact fetal membrane produced similar quantities of prostaglandin E2 (PGE2) (1-5 ng/ml). Choriodecidua and intact fetal membrane also produced very high levels of PGE2 metabolites (100-1000 ng/ml). The total production of PGE (PGE2 + PGE2 metabolites) was similar in intact fetal membrane and in choriodecidua, suggesting that the amnion, although a source of PGE2, contributes little to the overall PGE production by fetal membranes.

Amnion↗
PubMed1991

Differential metabolism of intracellular and extracellular arachidonic acid by decidual stromal cells and macrophages.

Term decidual stromal cells metabolized extracellular arachidonic acid to cyclo-oxygenase, lipoxygenase and epoxygenase products. Prostaglandins were the major metabolites from extracellular arachidonic acid. In contrast, intracellular arachidonic acid was metabolized mainly to an epoxygenase product, together with some lipoxygenase products. Decidual macrophages showed similar results, though these cells had higher production rates per cell of most metabolites. The calcium ionophore A23187 increased the levels of arachidonic acid released from the intracellular stores of decidual stromal cells and had variable effects on the production of cyclo-oxygenase, lipoxygenase and epoxygenase metabolites. Less than 15% of the total metabolites released from A23187-stimulated cells were cyclo-oxygenase products, which suggested that the cyclo-oxygenase products released by decidual stromal cells or macrophages may be mainly derived from extracellular arachidonic acid. This implies that the regulation of decidual cyclo-oxygenase may have a major role in determining prostaglandin output from this tissue.

Arachidonic Acids↗
PubMed1990

Limited transfer of prostaglandin E2 across the fetal membrane before and after labor.

The transfer of prostaglandin E2 (PGE2) across intact fetal membranes (amnion-chorion-decidua) obtained before and after the onset of labor was investigated using a novel system for in vitro fetal membrane culture. Studies using physiological concentrations of PGE2 showed that very little PGE2 will cross the membranes without being metabolised, before or after the onset of labor. It was only when pharmacological concentrations of PGE2 were used that the enzyme activity of the chorion was no longer able to prevent transfer of PGE2 without conversion to inactive metabolites. These results suggest that only small amounts of PGE2 from amnion are normally transferred across the chorio-decidua before or after the onset of labor, but the metabolism of PGE2 subsequent to transfer across the fetal membranes requires further assessment.

Arachidonic Acid↗
PubMed1987

Giant neurilemoma: unusual scrotal mass.

General physical examination of the male at whatever age is incomplete unless the scrotum and its contents are assessed. Since the scrotum consists of skin, fibrous connective tissue, smooth muscle, vessels, nerves, and a lining of simple squamous epithelium, a variety of tumors may arise in it. Scrotal tumors, however, are infrequent. Rare tumors are solitary neurilemomas. The English literature does not describe a giant neurilemoma of the scrotum.

Genital Neoplasms, Male↗
PubMed1986

Deletion loop mutagenesis of the nifL promoter from Klebsiella pneumoniae: role of the -26 to -12 region in promoter function.

Nine single C-to-T transitions were introduced into the -26 to -12 region of the Klebsiella pneumoniae nifL promoter by bisulphite mutagenesis of M13 heteroduplexes containing a 15 nucleotide single-stranded loop. Mutant promoter fragments were inserted into translational lac fusion vectors to utilise beta-galactosidase activity as a measure of promoter efficiency. Mutations in invariant nucleotides found in the consensus sequence for nif promoters gave a strong 'down' promoter phenotype with respect to transcriptional activation. Mutations in semi-conserved residues had a much weaker down phenotype, whereas a mutation which increased homology to the consensus sequence enhanced promoter strength. One mutant showed increased activation by ntrC and decreased activation by nifA.

Bacterial Proteins↗
PubMed1986

Income inequality, poverty and socioeconomic development in Bangladesh: an empirical investigation.

By analyzing the data for 1963-1964 through 1976-1977, this paper studies the pattern of income distribution and poverty in Bangladesh, and it also compares the socioeconomic status of the country in the mid-1970s with other developing countries of Asia, Africa, and Latin America. There has been a drastic increase in inequality and poverty in recent years, and this disturbing finding is reinforced by the fact that Bangladesh occupies the lowest position in the Third World in terms of a composite social index. The very poor within the poverty population suffered most, and the increase in the extent of poverty was most noticeable in the rural sector. The broad policy recommendation is that relatively more attention should be given to the social sectors white allocating resources for the country's future development.

Africa↗