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Biomedical subjects

J Ibrahim

Publications and source records attributed to J Ibrahim.

41 records · Page 3Linked to original sources
PubMed1989

Pinpointing the sites of hydroxylysine glycosides in peptide alpha 1-CB7 of bovine corneal collagen, and their possible role in determining fibril diameter and thus transparency.

Two cyanogen bromide fragments (alpha 1-CB7 and alpha 1-CB8) of bovine corneal stromal collagen have been isolated and characterized. These added to those characterized in our previous work account for 95% of the amino acid sequence of the alpha 1(1)-chain. The hydroxylysine glycoside content of each fragment was determined and in this way the general distribution of glycoside over the entire molecule was deduced accounting for all the galactosylhydroxylysine and most of the glucosylgalactosylhydroxylysine of this heavily glycosylated type I collagen. The characterization of fragments alpha 1-CB7 and alpha 1-CB8 has enabled us to resolve the controversy over the relative mobilities of these fragments on SDS gels. Fragment alpha 1-CB7 of bovine corneal collagen was digested by trypsin and by staphylococcal proteinase V8. The resultant peptides were isolated by gel and ion-exchange chromatography and identified in relation to the known amino acid sequence of type I collagen. The hydroxylysine glycosides were determined in the relevant peptides providing a complete account of their distribution along this part of the collagen molecule. Most of the glycoside was found in the gap region of collagen especially near the edges of the axial holes where it could act as a peg to facilitate fibre formation. In addition, some glycoside was found in the overlap region where, being unable to fit into axial holes, it might impede the growth of the fibre and, with other glycoside of the overlap region, might be responsible for the narrow fibres of corneal collagen that are essential for corneal transparency. This glycoside, with that previously found in the peptide alpha 1-CB3 is the only hydroxylysine glycoside identified in the overlap region of a type I collagen.

Amino Acid Sequence↗
PubMed1985

Frequency and distribution of binucleate cells in oral epithelium of several species of laboratory rodents.

Keratinocytes in certain regions of rodent oral epithelium have a tendency to form a peculiar type of binucleate cell. The nuclei, in contrast to those in binucleate cells in most other tissues, are closely apposed with a flat interface, tetraploid and of approx. equal size. Binucleate cells were absent from the oral epithelium of several unrelated non-rodent mammalian species, but they occurred in descending order of frequency in guinea pig, rat, hamster and mouse; they were in epithelia of the lining mucosa, but absent from epithelia of the masticatory mucosa. In buccal epithelium of the rat, they constituted 2.5 per cent of the basal cells and 8.2 per cent of the lower spinous cells. This frequency was maintained in the succeeding cell layers. Regions of stimulated epithelium in zinc-deficient rats showed a four-fold increase over controls in frequency in the germinative cell layers and persistently higher frequency in succeeding layers, including in parakeratin. The mode of formation of the cells is unknown, but it was not associated with a lag in cytoplasmic division.

Animals↗
PubMed1978

The role of non-biting flies in the transmission of enteric pathogens (Salmonella species and Shigella species) in Beirut, Lebanon.

In the summer and early autumn of 1974, flies were trapped in the Beirut districts of Ashraffiyah, Burj, Burj-Hammoud, Quarantine, the New Slaughter House, Ras Beirut, American University Campus, and the suburbs of Chiyah and Mreyjieh. Musca domestica, Muscina stabulans, Calliphora vicina, Phormia regina, Phaenicia sericata, Sarcophagidae spp. and Fannia canicularis were identified. The rural areas of Mreyjieh and Chiyah had higher densities of Musca domestica while higher densities of Calliphoridae spp. were found in the Slaughter House, Quarantine and Burj-Hammoud districts. Twenty-nine isolates, ten of Shigella spp. and 19 of Salmonella spp. were obtained from the bacteriological studies of 72 batches of Muscidae spp. and 84 Calliphoridae spp. These results indicate the hyperendemicity of salmonellosis and shigellosis in the areas under study, due to the prevalent poor sanity conditions and high fly infestation. It is suggested that in countries where valid health statistics are not available, bacteriological studies of flies may provide essential epidemiological information.

Animals↗
PubMedDate not supplied

Non-radioisotopic glucose turnover in children with falciparum malaria and enteric fever.

To determine whether glucose turnover is increased in acute falciparum malaria compared to enteric fever in children, steady-state 6,6-D2-glucose turnover was measured in 9 Malaysian children with uncomplicated malaria (6 males and 3 females; median age 10 years, body weight 22 kg) and in 12 with uncomplicated enteric fever (8 males and 4 females; median age 10 years, body weight 24 kg) in acute illness, after quinine (5 malaria patients) and in convalescence. Baseline plasma glucose concentrations in malaria and enteric fever were similar (all values are medians [ranges in brackets]) 5.6 [3.2-11.3] vs. 5.5 [4.2-8.0] mmol/L), as were serum insulin levels (5.6 [0.4-26.5] vs. 6.8 [1.1-22.5] milliunits/L; P > 0.4). Glucose turnover in the malaria patients was higher than in patients with enteric fever (6.27 [2.71-6.87] vs. 5.20 [4.50-6.08] mg/kg.min; P = 0.02) and in convalescence (4.74 [3.35-6.79] mg/kg.min; P = 0.05 vs. acute malaria study), and fell after quinine together with a rise in serum insulin (P = 0.03). Basal plasma lactate concentrations were higher in enteric fever than in malaria (3.4 [1.8-6.4] vs. 0.8 [0.3-3.8] mmol/L; P < 0.0001) and correlated inversely with glucose turnover in this group (rs = -0.60; n = 12; P = 0.02). These data suggest that glucose turnover is 20% greater in malaria than in enteric fever. This might reflect increased non-insulin-mediated glucose uptake in falciparum malaria and/or impaired gluconeogenesis in enteric fever, and may have implications for metabolic complications and their clinical management in both infections.

Adolescent↗