PubMed Health⌕ Search

Biomedical subjects

M Sekar

Publications and source records attributed to M Sekar.

5 recordsLinked to original sources
PubMed1998

Quinoline Alkaloids: Synthesis of Pyrano

Polyphosphoric acid (PPA)-catalyzed cyclization of 2-ono-3-vinylquinolinecarboxylic acid (1) yielded 3,4-dihydro-2,2-dimethyl-2H-pyrano[2,3-b]quinoline (4). The same reaction of 4-methoxy-2-oxo-3-vinylquinolinecarboxylic acid (1g) afforded 4-methoxy-2,2-dimethylpyrano[2,3-b]quinoline (4g), which on hydrolysis with ethanolic hydrochloric acid gave khaplofoline (5). The Prevost reaction of 4-methoxy-3-prenylquinolin-2-one (6) using I2/HgO in acetic acid yielded 4-methoxy-2-isopropylfuro[2,3-b]quinoline (7). Compound 7 on reduction with H2/Pd-C followed by N-methylation and de-O-methylation afforded lunacrine (10a). A similar reaction sequence on 6b gave demethoxylunacrine (10b).

Journal Article↗
PubMed1998

Synthesis of some novel 2-oxo-pyrano(2,3-b)- and 2-oxo-pyrido(2,3-b)quinoline derivatives as potential antimalarial, diuretic, clastogenic and antimicrobial agents.

The 2-chloro-3-formyl quinoline derivatives (1a-e) on treatment with acetic anhydride and sodium acetate, afforded the corresponding novel 2-oxopyrano(2,3-b) quinoline derivatives (2a-e), and these were subjected to ammonia treatment to yield the corresponding naphthyridine derivatives (3a-e). The prepared compounds (2a-e) were tested for their antimalarial, diuretic, clastogenic and antimicrobial properties. Not all the compounds showed a diuretic effect and the significant increase in the frequency of micronuclei shows that they are non-clastogens, whereas the 7-chloro derivative (2e) was a very effective antimalarial agent against the mosquito species. All the compounds were found to have optimum antimicrobial activity against Staphylococcus aureus, Escherichia coli and Salmonella typhi. Compounds 2d and 2e were found to be most active against the bacteria tested.

Animals↗
PubMed1997

Predicting difficult intubation--a comprehensive scoring system.

A study was conducted in an attempt to devise a simple and more accurate method of predicting difficult intubation. Prospective assessments were made in 282 patients and retrospective assessment in 16 patients with regard to 21 anatomical factors which were correlated with the laryngoscopic view at intubation. Twelve factors correlated significantly with difficult intubation. Four of these were eliminated after multifactorial analysis. A scoring system was devised, assigning points to each variable based on its discriminative value. A score of 6 or more correctly identified 22 out of the 23 difficult intubations and there were 50 false positives (sensitivity, specificity and PPV of 96%, 82% and 31% respectively). When negative scoring was done for factors favouring easy intubation, false positives were reduced to 36, but only 20 difficult cases could be identified correctly.

Adult↗
PubMed1996

Myelosuppression associated with azathioprine-allopurinol interaction after heart and lung transplantation.

It is widely recommended that, during concurrent therapy with allopurinol, the azathioprine dosage should be decreased by at least two thirds. We retrospectively studied compliance with this guideline in 24 patients who had commenced allopurinol at a median of 33 months (range, 2-145 months) after heart and/or lung transplantation. The median reduction in azathioprine dose at initiation of allopurinol was 73.3% but ranged from 0% to 90% (>67% in 14 patients). Within 3 months, 11 (46%) of the patients became leukopenic (white blood cell count <4 x 10(9)/L), 7/23 (30%) became moderately anemic (hemoglobin <10 g/dl), and 5/23 (22%) became thrombocytopenic (platelets <150 X 10(9)/L). Decreasing the dose of azathioprine by two thirds or greater reduced but did not abolish the risk of myelotoxicity. These data highlight the need for close hematological monitoring of patients treated with this drug combination. Agents other than allopurinol should be considered for treating hyperuricemia after thoracic organ transplantation.

Adult↗