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Biomedical subjects

S A Lang

Publications and source records attributed to S A Lang.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effects of vagus nerve on heart rate and ventricular contractility in chicken.

We determined the effects of vagus nerve stimulation on cardiac cycle length and on ventricular contraction and relaxation in 18 chickens anesthetized with pentobarbital. Right vagus stimulation at a constant frequency of 35 Hz prolonged cycle length by 190%, whereas left vagus stimulation at the same frequency increased cycle length by 136%. When one burst of stimuli was delivered to the right vagus nerve each cardiac cycle, but the timing of the stimuli was changed within the cardiac cycle, the response of the avian pacemaker cells varied substantially with the timing of the stimuli. Right and left vagus stimulation at a constant frequency of 20 Hz depressed ventricular contraction by 62 +/- 6 and 52 +/- 6%, respectively, and depressed ventricular relaxation by 56 +/- 7 and 53 +/- 7%, respectively. These results indicate that in the chicken the chronotropic effects of right vagus stimulation are greater than those of left vagus stimulation, whereas right and left vagus stimulation are approximately equipotent on ventricular contraction and relaxation.

Animals↗
PubMed1988

Role of prostaglandins in blood-induced vasoconstriction of canine cerebral arteries.

We tested the hypothesis that the vasoconstriction produced by the application of blood to the adventitial surfaces of the vessels of an isolated perfused canine circle of Willis preparation was mediated by products of prostaglandin metabolism. In this preparation (perfused at constant flow and outflow pressure), topical application of blood produced an average 16.6 +/- 1.8 (SE) mm Hg increase in inflow pressure. This response could be prevented with four structurally dissimilar cyclooxygenase inhibitors (aspirin, indomethacin, ibuprofen, and meclofenamate), suggesting that the blood-induced increase in vascular resistance was mediated by prostaglandins. Imidazole, an inhibitor of thromboxane synthetase, had no effect on the blood response. Further support for the involvement of prostaglandins in this response was provided by additional experiments in which either arachidonic acid, prostaglandin E2 (PGE2), or PGF2 alpha were administered. All three treatments produced vasoconstriction. These results suggest that the vessels of this preparation are capable of synthesizing vasoconstrictor prostaglandins and indicate that they are reactive to known vasoactive prostaglandins.

Animals↗
PubMed1982

Antitumor agents. 2. Bisguanylhydrazones of anthracene-9,10-dicarboxaldehydes.

9,10-Anthracenedicarboxaldehyde bis[(4,5-dihydro-1H-imidazol-2-yl)hydrazone] (bisantrene, VI-1) showed anticancer activity in mice vs. both leukemias and solid tumors. Increases in life span vs. the following neoplasms were: P-388 leukemia, 137%; B-16 melanoma, 122%; Lieberman plasma cell tumor, greater than 85%; colon tumor 26, 150%; Ridgway osteogenic sarcoma, 85%. There were significant numbers of long-term survivors. Both DNA and RNA synthesis were strongly inhibited. The drug was resistant to biodegradation and was bound strongly to tissues; in monkeys the half-life for disappearance from serum was 6 days. Related hydrazones were synthesized, and structure-activity relationships are discussed. Two routes to ring-substituted anthracene-9,10-dicarboxaldehyde intermediates were developed.

Animals↗
PubMed1980

Anti-inflammatory and analgesic profile of amidines of 3-amino-1,2,4-benzotriazine and 3-amino-1,2,4-benzotriazine-1-oxide.

Several formamidine and acetamidine derivatives prepared from 3-amino-1,2,4-benzotriazine and 3-amino-1,2,4-benzotriazine-1-oxide displayed an aspirin-like anti-inflammatory and analgesic profile. The test systems include adjuvant-induced arthritis in rats, carrageenan-induced edema in rats, UV-induced erythema in guinea pigs, the analgesic gait test, the antipyretic test, and GI ulcer studies.

Animals↗
PubMed1980

Antiamebic amidines and sulfonamides of 5- and 6-amino-2,3-bis(4-alkyl-1-piperazinyl)quinoxalines.

A series of amidines and sulfonamides of 5- and 6-amino-2,3-bis(4-alkyl-1-piperazinyl)quinoxalines was synthesized and tested against cecal and hepatic forms of Entamoeba histolytica infections in rats and hamsters, respectively. Four compounds (5, 6, 8, and 9) were found to have acceptable activity against infections in both species but were too toxic to be considered for use in man.

Amebicides↗
PubMed1978

Bisamidines of 2,6-diaminoanthraquinone as antiamebic agents.

A series of bisamidines of 2,6-diaminoanthraquinone was synthesized and tested against cecal and hepatic forms of Entamoeba histolytica infections in rats and hamsters, respectively. A number of compounds were found to have good activity against infections in both species.

Amebiasis↗
PubMed1978

Antitubercular 2,8-bis(alkylaminomethyl)phenazines.

The preparation and antitubercular properties of a series of 2,8-bis(alkylaminomethyl)phenazines are described. These compounds all inhibited the growth of Mycobacterium smegmatis ATCC 607 in vitro. 2,8-Bis(dibutylaminomethyl)phenazine (5c) was also active against a lethal Mycobacterium tuberculosis H37Rv infection in mice.

Animals↗
PubMed1975

Beta-aminocinnamonitriles as potential antiinflammatory agents.

A number of beta-aminocinnamonitriles have been prepared by the reaction of salts of acetonitrile and propionitrile with benzonitrile. These materials were evaluated in the carrageenan antiinflammatory screen in Royal Hart, Wistar strain rats. Despite good weight gains in the parent molecule, beta-aminocinnamonitrile (1), only marginal activity was found in related compounds and some possible "metabolites."

Animals↗
PubMed1975

4-Amino-5-arylpyrimidines as antiinflammatory agents.

4-Amino-5-arylpyrimidines were synthesized by a variety of methods and have demonstrated antiinflammatory activity in the carrageenan-induced edema in the rat but displayed little activity against adjuvant-induced arthritis in rats or against uv-induced erythema in guinea pigs.

Animals↗