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Biomedical subjects

S Mohammed

Publications and source records attributed to S Mohammed.

At least 55 records · Page 3Linked to original sources
PubMed1990

Functional domains of the HIV-1 rev gene required for trans-regulation and subcellular localization.

The rev gene of human immunodeficiency virus type 1 (HIV-1) encodes a 116 amino acid nuclear regulatory protein (Rev) that increases the cytoplasmic expression of viral mRNAs containing the Rev response element (RRE) and coding for the structural proteins, Gag and Env. To identify the functional domains of Rev, amino acid deletion and chain termination mutations were introduced in the Rev coding region. The ability of these mutants to increase the cytoplasmic expression of a Rev-test plasmid (pSV-AR), containing the RRE cloned into the 3' noncoding region of the CAT gene in plasmid pSV2CAT, was examined in transient expression assays in HeLa cells. Our results indicate that three distinct regions mapping within the N-terminal 98 amino acids of Rev are essential for its activity. The subcellular localization of the various Rev proteins was examined in COS cells by indirect immunofluorescence. Rev was found to localize predominantly in the nucleolus of transfected cells. All mutant Rev proteins, with the exception of a deletion mutant (rev delta 41-44) lacking four Arg residues of a highly basic domain, were found to localize in the nucleolus. Mutant rev delta 41-44 exhibited weak diffuse fluorescence in the nucleus with a tendency to accumulate in the cytoplasm. A 15 amino acid region encompassing this basic domain (38-52) when fused to the Escherichia coli beta-galactosidase gene efficiently directed the fusion gene product to the nucleus and nucleolus, suggesting a role for this domain in the nucleolar localization of Rev.

Amino Acid Sequence↗
PubMed1990

Cerebrovascular accidents (strokes) in children with sickle cell disease residing at high and low altitudes of Saudi Arabia.

In a 3-year period, eight cases of cerebrovascular accident were seen out of 400 patients with sickle cell disease residing at high and low altitudes of Asir Province of Saudi Arabia. They were all Saudi nationals and comprised five boys and three girls of ages ranging from 3.5 to 9 years. They had varied clinical presentations of their cerebrovascular accident. Cranial computed tomography in seven of them showed abnormality in the region of the middle cerebral circulation. Management and some suggested factors contributing to the occurrence of the cerebrovascular accident are discussed.

Altitude↗
PubMed1990

Sickle cell disease in permanent residents of mountain and low altitudes in Saudi Arabia.

Report of a comparative study of sickle cell disease in permanent residents of mountain and low altitudes in south-western Saudi Arabia. The ambient oxygen tensions at these altitudes are 14 and 19 kPa (112 and 144 mmHg) respectively. The frequencies of sicklaemic-related illness requiring medical intervention, and hospitalisation due to crisis and complications of the disease, were about twice as great in highlanders as in lowlanders. The incidence and severity of the complications were similar in both locations. No splenic syndrome was observed in those with the disease or trait in either location. Haemoglobin concentration was 10% greater in mountain normals than in their lowland counterparts; the corresponding figure for sicklers was 5%. Erythrocyte 2,3 diphosphoglycerate concentration was 13% greater in mountain than valley patients; the corresponding figure for normals was 4%. We propose that the elevated diphosphoglycerate in mountain patients might contribute to their higher frequency of sicklaemic illness as well as partially blunting their erythropoietic drive.

2,3-Diphosphoglycerate↗
PubMed1989

[Giant secondary vaginal calculus].

The development of a large vaginal stone in a 25-year-old female, correlated with vesicovaginal fistula, is presented. The stone, composited of struvite and carbonate apatite, formed around non-absorbable surgical suturing material in urine with urease producing (P. mirabilis) bacterial infection. The stone was removed by simple lithotripsy technique. Attention is taken for the importance of stone prevention.

Adult↗