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Biomedical subjects

A Hasan

Publications and source records attributed to A Hasan.

102 records · Page 6Linked to original sources

Ovarian tumors complicating pregnancy.

Between the years 1977 and 1981, 9037 patients gave birth at Jordan University Hospital (JUH). Among these ten patients were found to have an associated ovarian tumor, an incidence of one in 900 deliveries. Benign cystic teratomas were the most common ovarian tumors found, followed by mucinous cystadenomas. All of the tumors were benign except one case of Burkitt's lymphoma.

Adolescent↗

Ascorbic acid-induced uricosuria. A consequency of megavitamin therapy.

The effect of ascorbic acid on the serum and urinary uric acid was studied in 14 subjects. Two to 6 h after the ingestion of 4.0 g of ascorbic acid, the fractional clearance of uric acid increased to 202% +/- 41% of the control value. This uricosuria was inhibited by pyrazinamide and by low-dose acetylsalicylic acid, but was not accompanied by an increase of the creatinine clearnace. Ascorbic acid did not diminish protein-bound uric acid. In 3 subjects who ingested 8.0 g of ascorbic acid for 3 to 7 days the serum uric acid decreased by 1.2 to 3.1 mg/dl as a result of a sustained uricosuria. These results suggest that ascorbic acid could invalidate studies involving the measurement of uric acid and obscure the diagnosis of gout in some cases. Theoretically it could precipitate attacks of gouty arthritis or renal calculi in predisposed persons. These observations show a pharmacologic effect of megadoses of a simple vitamin.

Ascorbic Acid↗

2-substituted thioadenine nucleoside and nucleotide analogues: synthesis and receptor subtype binding affinities (1).

The design, synthesis, and receptor subtype binding affinities of several 2-substituted thioadenosine nucleoside and nucleotide analogues are described. Alkylation of 2-thioadenosine (1) with iodopentenylboronic acid followed by iododeboronation gave 2-((E)-1-iodo-1-penten-5-yl) thioadenosine (9). Compound 1 on treatment with 4-nitrobenzyl bromide and propargyl bromide furnished compounds 3 and 5, respectively. The 5'-monophosphate analogues of compounds 3, 5, 7, and 9 were prepared similarly using 2-thioadenosine 5'-monophosphate (2). Treatment of 1 with bromoethylamine hydrobromide provided 2-[(aminoethyl)thio]adenosine (11) which on coupling with N-succinimidyl 3-(4-hydroxyphenyl)propionate gave 2-[[[3-(4-hydroxyphenyl)propionamido]ethyl]thio]adenosine (12). Iodination of 12 gave 2-[[[3-(4-hydroxy-3-iodophenyl)propionamido]ethyl]thio]adenosine (13). Compounds 3-13 were evaluated for their affinities toward A1 and A2 adenosine receptors in rat brain cortex and striatum, respectively using [3H]DPCPX and [3H]CGS21680 as ligands. The nucleotide analogues 4, 6, 8, and 10 inhibited binding of [3H]DPCPX by 10-20% and of [3H]CGS21680 by 40-50% at a concentration of 100 microM suggesting weak affinity toward adenosine receptors. The nucleoside analogues 3, 5, 7, 9, 12, and 13 inhibited the A2 receptor binding of [3H]CGS21680 with Ki values of 1.2-3.67 microM, while A1 receptor binding of [3H]DPCPX was inhibited with Ki values 10-17 microM. The A1/A2 ratios suggest 4-8-fold A2 receptor selectivity.

Adenine Nucleotides↗

Studies on base-boronated oligonucleotides. 2 (1). Incompatibility of DMT and cyanoborane groups during oligonucleotide synthesis.

The cyanoborane (-BH2CN) nucleosides and nucleotides are a new class of compounds that mimic natural and synthetic congeners in many ways and exhibit interesting biochemical and biophysical properties. The B-N bond is isoelectronic with the C-N+ bond of N7-alkylated 2'-nucleosides, as well as the C-C bond of naturally occurring 7-alkyl-7-deazanucleosides. These compounds differ from normal guanosine in that they are incapable of hydrogen bonding at the 7-position. The syntheses of N7-cyanoborane 2'-deoxyguanosine, N2-(dimethylaminomethylene)-N7-cyanoborane 5'-(dimethoxytrityl)-2'-deoxyguanosine (3), and N2-isobutyryl-N7-cyanoborane 5'-(dimethoxytrityl)-2'-deoxyguanosine (9) are described. Removal of the dimethoxytrityl (DMT) group from 3 or 9 is accompanied by significant loss of the cyanoborane moiety. Additionally, dimethoxytritylation of a cyanoboronated nucleoside leads to partial deboronation, thus limiting use of the commercially available 5'-DMT nucleosides as viable precursors in base-boronated oligonucleotide synthesis. The incompatibility of the cyanoborane moiety under DMT removal/addition conditions necessitated the search for an alternative method of protecting the 5'-hydroxyl of the nucleoside. This paper addresses the possible cause of deboronation and describes the synthesis of N7-cyanoboronated nucleosides by a method that avoids transient protection of the sugar hydroxyls.

Boron Compounds↗

Single lung transplantation with simultaneous contralateral pneumonectomy for cystic fibrosis.

A 24-year-old man with cystic fibrosis and marked reduction of volume of the left hemithorax caused by skeletal asymmetry and mediastinal shift underwent successful right single lung transplantation with simultaneous left pneumonectomy. Despite significant preoperative microbiologic contamination, it proved possible to sterilize the pneumonectomy space and no airway complications occurred. Good long-term results have been achieved, and the historic assumption that single lung transplantation is unsuitable for patients with septic lung disease is challenged.

Adult↗

Surgical management of infective endocarditis after heart-lung transplantation.

Bacterial endocarditis after heart-lung transplantation has not been described. We report Staphylococcus aureus bacterial endocarditis in a 12-year-old boy after heart-lung transplantation. He was found to have an apparently free vegetation in his left ventricle, which was surgically removed. After a stormy postoperative period, he successfully recovered and remains well after 6 months.

Acute Disease↗