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Biomedical subjects

S Levine

Publications and source records attributed to S Levine.

At least 541 records · Page 30Linked to original sources
PubMed1976

Experimental allergic encephalomyelitis in aged F344 rats.

Experimental allergic encephalomyelitis (EAE) was produced in 2- to 24-mo.-old F344 rats by active immunization and by passive transfer of lymphoid cells (adoptive immunization) from young rats. With both methods, some 24-mo.-old rats had a reduced ability to develop this autoimmune disease. However, the immunological deficit was related to incidental serious diseases rather than to old age per se. The aged F344 rat is not a suitable model for comparing EAE to multiple sclerosis in man because the decreased incidence of multiple sclerosis after the age of 50 is not related to other serious illnesses.

Age Factors↗
PubMed1976

Effect of tilorone on susceptibility of mice to primary or secondary infection with Listeria monocytogenes.

Subcutaneous administration of the drug tilorone did not increase the susceptibility of CD-1 male mice to intravenous or intraperitoneal infection with an alpha-toxin-deficient mutant of the Smith diffuse strain strain of Staphylococcus aureus. In contrast, a single injection of this drug greatly increased the susceptibility of mice to an intravenous or an intraperitoneal infection with Listeria monocytogenes, an intracellular parasite. The effects of tilorone, which were maximal when the drug was administered on the day of the listerial challenge or one day thereafter, were reflected by relatively lower mean lethal dose values and enhanced proliferation of Listeria in the spleen and liver. The ability of tilorone, administered at the time of listerial challenge, to decrease the resistance against the challenge was partially abrogated by previous administration of the same drug. Tilorone, administered at the time of immunization with a very small number of viable Listeria, greatly enhanced the potency of the immunization. On the other hand, tilorone, administered to Listeria-immunized mice near to the time of a listerial challenge, slightly reduced the protective effects of the prior immunization.

Animals↗
PubMed1976

Ventilatory stimulation by sodium salicylate: rols of thoracic receptors.

To explore the possibility that salicylates can stimulate VE via an extracranial mechanism, heads of dogs were perfused entirely by a support dog with blood of unchanging gas composition; spinal cord remained intact. The carotid bodies lay within the region of the perfused head; the aortic bodies were denervated. Intra-arterial infusion of sodium salicylate (150-225 mg/kg) into the body of these head-perfused animals elicited large increases in VE (188+/-11%), although significant amounts of salicylate did not reach the head or carotid body. In any case, when the same dose of salicylate was selectively administered to the head, increases in VE were limited to 23+-8%. To determine the contribution of thoracic receptors to the increase in VE elicited by salicylates, a subsequent group of head-perfused animals underwent complete spinal transection at the first lumbar level. Nnetheless, intra-arterial infusion of sodium salicylate (150-225 mg/kg) into the body of these head-perfused animals still elicited large increases in VE (111+/-13%). It is concluded that thoracic receptors (other than the aortic bodies) mediate a significant portion of the increase in VE elicited by intra-arterial infusion of sodium salicylate.

Animals↗
PubMed1976

Personality self-perceptions of male heart patients and their wives: issues of congruence and "coronary personality".

This study examines personality self-ratings of 283 married men who had recently experienced a first myocardial infarction and who previously had been free from major disease. Similar data were collected from their "non-cardiac" wives. Results indicated that several traits often identified as descriptive of "coronary-prone" personality had high mean ratings in both husband and wife populations. In addition, factor analysis revealed a similar pattern of factors in each group. However, inspection of correlations showed for individual items, men with so-called "coronary-prone" personality traits did not generally have wives with these traits. Husbands and wives tended to agree regarding each other's personality self-ratings. Implications of these husband-wife data are discussed in regard to questions on the role of "coronary-prone" personality in heart disease.

Female↗
PubMed1976

Endotoxin toxicity in rats is enhanced by tilorone.

The relatively nontoxic drug, tilorone, greatly enhanced the susceptibility of rats to lethal effects of endotoxin. The magnitude of the synergy was similar to that produced by adrenalectomy, but the effect of tilorone was not mediated by the adrenal glands. The histopathologic effects of endotoxin plus tilorone resembled those produced by much larger doses of endotoxin alone, including instances of the generalized Shwartzman reaction.

Adrenalectomy↗
PubMed1976

Necrotic myelopathy (myelomalacia) in rats with allergic encephalomyelitis treated with tilorone.

Necrosis of the spinal cord was produced by administering tilorone to rats before or during the incubation period of experimental allergic encephalomyelitis (EAE). Under slected conditions of dose and timing, the drug delayed onset of clinical signs but did not prevent progression to paralysis. The lymphocytic component of the inflammatory lesions was reduced, but this was accompanied by a dramatic increase of monocytes in the spinal cord, followed by softening (myelomalacia). This new variant of EAE simulates necrotic myelopathy in man. The similarity provides support for an autoimmune etiology of the latter. Furthermore, the inverse relation between lymphocytic cuffs around vessels and massive monocytic infiltration of the cord adds to the growing evidence that lymphocytic cuffs protect the neural parenchyma by "vascular blockade."

Animals↗
PubMed1976

The effect of maternal and fetal corticosteroids on the development of function of the pituitary-adrenocortical system.

The pituitary-adrenocortical system of rat fetuses was stimulated (larger adrenals at birth) by maternal adrenalectomy, or suppressed (smaller adrenals at birth) by implantation of an ACTH secreting pituitary tumor (MtTF4). Offspring were delivered by caesarean section and fostered to untreated females. Offspring of intact females delivered by caesarean section and normally delivered offspring of intact mothers both fostered to untreated lactating females served as controls. Body growth in the first three weeks of life was delayed in offspring of tumor bearing mothers in Control-fostered subjects as compared to the 2 other groups. At 70 days of age female offspring of the tumor implanted and adrenalectomized mothers, as well as the Control-caesarean females, had smaller adrenals than Control-fostered animals of the same sex. The adrenal size of males was not significantly affected. No significant differences were found in resting concentrations of corticosterone in plasma, although offspring of adrenalectomized mothers had high values. Suppressed adrenal response to ether stress was found in offspring of tumor bearing mothers. The supposition is that interference with maternal pituitary-adrenocortical activity during pregnancy has a long lasting effect on fetal hypothalamo-pituitary-adrenocortical system.

Adrenal Cortex Hormones↗
PubMed1976

Influence of colony type on susceptibility of gonococci to killing by human serum.

The virulence of gonococci is related to colony morphology and has been attributed to pili found only on the virulent types. Because complement-mediated serum killing is a major defense against other Gram-negative bacteria, we tested the resistance to normal human serum of virulent and avirulent types from two strains. Virulent types were more resistant than avirulent types. This stable, relative serum resistance of virulent colony types persisted during prolonged passage on agar. In addition, virulent types acquired complete resistance after exposure to serum which was rapidly lost during passage on agar. This acquired, complete resistance helps explain the observation that freshly isolated gonococci are resistant to their host's serum, but lose this resistance when passed on agar. The capacity to become resistant to the serum of newly infected patients may contribute to virulence of T1 and T2 gonococci.

Blood Bactericidal Activity↗
PubMed1975

Erythrocytosis and renal cell carcinoma with pulmonary metastases: case report with 18-year followup and brief discussion of literature.

A 42-year-old man was admitted to the Cancer Division of the American MedicalCenter in February, 1956. He had been treated for erythrocytosis beginning 6 months previously, with reduction of his hemoglobin to relatively normal values. On admission, a huge tumor of the left kidney was palable. Roentgenograms of the chest demonstrated small bilateral pulmonary metastases. A left nephrectomy was per formed, followed by wedge resection of a total of 16 metastatic nodules, 12 of which showed metasticrenal carcinoma. It is now 18 years since the last thoracotomy and the patient is well, leading a normal life, and free of any demonstrable malignant disease and any evidenceof erythrocytosis.

Adenocarcinoma↗
PubMed1975

Effects of prior aversive stimulation on heart rate responses to open field exposure in the rat.

Heart rate (HR) responses to open field (OF) exposure were compared between rats previously exposed to intense, inescapable electric shock (preshock, PS) and Controls. Results indicated that (1) Control animals showed a steady increase in HR across a 3 min exposure on each of 4 days of testing, while PS animals showed an initial HR deceleration followed by partial recovery on each day; (2) the HR response of PS animals in the OF was not related to any HR response to shock during treatment; and (3) the HR responses of both PS and Control animals were specific to the OF situation, with both groups showing steady HR deceleration across 3 min after being placed in their home cages. Results were discussed in terms of (1) the apparently altered perception of environmental change produced by PS, and (2) the possible role of HR acceleration in Controls in terms of minimizing the impact of aversive stimulation.

Animals↗