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Biomedical subjects

S Moore

Publications and source records attributed to S Moore.

At least 379 records · Page 21Linked to original sources
PubMed1975

Synthesis and antitumor activity of 2-deamino- and N2-(gamma-hydroxypropyl)actinomycin D.

2-Deamino- and N2-(gamma-hydroxypropyl)actinomycin D were synthesized by modification of the parent actinomycin D molecule at the 2 position of the phenoxazinone moiety. The common intermediate was 2-deamino-2-chloroactinomycin D. Catalytic hydrogenation of this material afforded the 2-deamino derivative while treatment with gamma-hydroxypropylamine yielded the N2-(gamma-hydroxypropyl) derivative. These 2-substituted actinomycin D derivatives were less potent in microbiological assays than the parent compound. Evaluation of activity in vivo against three murine tumor systems indicated that optimal dose levels of 2-deaminoactinomydin D were 50 times greater than toxic dose levels of actinomycin D. N2-(gamma-hydroxyporpyl)actinomycin D exhibited antitumor activity similar to the parent compound.

1-Propanol↗
PubMed1975

Social position and competition in laboratory rats.

Two experiments with rats as subjects are described, which control for social position, i.e., relative dominance/submission, in an appetitive social learning-performance setting. The results indicate that animals that perform quite effectively when alone exhibit significantly reduced levels of responding when placed into a social environment. The severity of the response decrement is, at least in part, a function of the relative social position of the subjects involved. A dominant male made few responses when paired with another dominant male. Yet, a dominant subject made even fewer responses when paired with a submissive subject, which bar pressed at approximately half the individual level. These findings are interpreted as suggesting that social position, with its accompanying characteristic form of aggression, is an important determinant of performance in a social learning environment.

Adaptation, Psychological↗
PubMed1975

Endothelial injury induced by thrombin or thrombi.

A variety of blood constituents was injected into an isolated segment of rabbit aorta to determine which elements might be involved in early endothelial injury. Test materials consisted of platelet-rich plasma (PRP) alone; PRP plus adenosine diphosphate (ADP); PRP plus tendon extract; PRP plus thrombin; ultrasonicated PRP alone; platelet-poor plasma alone; and thrombin in saline. Each experimental mixture was left in the aorta for 15 minutes, followed by reflow for 20 minutes. The vessel was then fixed by glutaraldehyde perfusion. Thick sections of the entire circumference of the aorta were taken for phase contrast microscopy and representative arease were selected for electron microscopy. In control PRP alone, platelet-poor plasma alone and with PRP plus ADP there were occasional subendothelial vesicles. When PRP plus thrombin and platelet-poor plasma plus thrombin were injected separately to form a thrombus or when thrombin in saline was used, there was extensive subendothelial vesiculation with focal ulceration and adherence of thrombus to endothelium. Severe injury was associated with the presence of thrombin initiating the polymerization of fibrinogen to fibrin. Electron micrographs demonstrate the earliest lesion as a disruption of the superficial fibrilliary elastica with separation of overlying endothelium.

Adenosine Diphosphate↗
PubMed1975

Repeated endothelial injury and induction of atherosclerosis in normolipemic rabbits by human serum.

Since Duguid suggested that atherosclerosis represents essentially the organization of mural thrombi, there have been many attempts to produce the disease experimentally by damaging the arterial wall. A single injury to the inner lining of an artery causes lipid-free lesions, composed of smooth muscle cells and collagen, covered by endothelium. Previously, we reported the development of atherosclerotic lesions in normolipemic rabbits as a result of repeated or continuous intimal injury by an indwelling aortic polyethylene catheter. However, it was difficult to control the location or duration of the intimal injury. The present investigation was designed to produce repeated endothelial injury in a defined segment of rabbit carotid artery. Sixty-two rabbits received injections of either lymphocytotoxic-positive (LP) or lymphocytotoxic-negative (LN) human serum into a segment of left carotid artery. Autologous rabbit serum was injected into the right carotid artery as a control. Eight rabbits received a single injection of LP and were killed 4 weeks latermforty-two rabbits received injections of human serum at weekly intervals, for a maximum of four injections, and were killed 1 week after the last injectionmthirty-two of 42 rabbits received repeated injections of LP; 10 received repeated injections of LN. Raised, lipid-containing lesions were present in 21 of 26 rabbits receiving four repeated injections of LP. No, or very minimal (fewer than three cells thick), intimal thickening was found in the 10 LN rabbits and in all control right carotid arteries. In eight rabbits receiving one injection of LP, fibrous intimal thickening without lipid accumulation, fatty streaks, and edematous plaques were found. Electron microscopy of arteries from 12 rabbits sampled at 1,5, and 60 minutes after exposure to LP indicated that the initial damage was loss of endotheliummthe results consistently showed lipid in raised, thrombus-covered (non-reendothelialized) lesions. Nonraised, endothelialized lesions did not show lipid. These findings support the belief that atherosclerosis occurs in response to repeated endothelial injury.

Animals↗
PubMed1974

Pancreatic ribonuclease: enzymic and physiological properties of a cross-linked dimer.

Monomeric ribonuclease A has very low activity toward typically double-stranded RNA's; the dimeric form of ribonuclease A obtained by cross linking the enzyme by dimethyl suberimidate has more than 78 times the activity of the monomer toward polyadenylate . polyuridylate and 440 times the activity of the monomer toward the double-stranded RNA of a virus from Penicillium chrysogenum. The half-life of the dimer in the bloodstream of the rat is 12 times that of the mononmer.

Animals↗