Biomedical subjects

S Y Stevens

Publications and source records attributed to S Y Stevens.

25 records · Page 2Linked to original sources

PubMed1999

Psychosocial predictors of natural killer cell mobilization during marital conflict.

This study examined how specific emotions relate to autonomic nervous and immune system parameters and whether cynical hostility moderates this relationship. Forty-one married couples participated in a 15-min discussion about a marital problem. Observers recorded spouses' emotional expressions during the discussion, and cardiovascular, neuroendocrine, and immunologic parameters were assessed throughout the laboratory session. Among men high in cynical hostility, anger displayed during the conflict was associated with greater elevations in systolic and diastolic blood pressure, cortisol, and increases in natural killer cell numbers and cytotoxicity. Among men low in cynical hostility, anger was associated with smaller increases in heart rate and natural killer cell cytotoxicity. These findings suggest that models describing the impact of stress on physiology should be refined to reflect the joint contribution of situational and dispositional variables.

Adult↗

PubMed1999

ACE inhibition improves cardiac NE uptake and attenuates sympathetic nerve terminal abnormalities in heart failure.

Cardiac sympathetic nerve terminal dysfunction plays an important role in the downregulation of myocardial beta-adrenoceptors in heart failure. To determine whether chronic angiotensin-converting enzyme (ACE) inhibition improved cardiac sympathetic nerve terminal function and hence increased myocardial beta-adrenergic responsiveness, we administered ACE inhibitors to dogs with chronic right-sided heart failure (RHF) produced by tricuspid avulsion and pulmonary artery constriction. The RHF animals exhibited fluid retention, elevated right heart filling pressures, blunted inotropic response to isoproterenol, and reduced beta-adrenoceptor density. These changes were accompanied by decreases in right ventricular norepinephrine (NE) uptake and neuronal NE histofluorescence and tyrosine hydroxylase immunoreactive profiles. ACE inhibitors had no effect on the production of heart failure but greatly reduced the attenuation of cardiac NE uptake, neuronal NE histofluorescence, and tyrosine hydroxylase immunoreactive profiles. ACE inhibition also improved the inotropic response to isoproterenol and restored myocardial beta-adrenoceptor density. The changes probably are caused by reduction of cardiac NE release by ACE inhibition and may contribute to the beneficial effects of ACE inhibitor therapy in patients with chronic heart failure.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1998

Sympathectomy-induced immune changes are not abrogated by the glucocorticoid receptor blocker RU-486.

Removal of sympathetic noradrenergic input to the immune system by injection of 6-hydroxydopamine (6-OHDA) triggers increases in antigen-specific in vitro splenocyte proliferation and cytokine production in BALB/cJ and C57B1/6J mice. This examines the possible role of glucocorticoids in these previously reported changes. In both strains, chemical sympathectomy triggers an elevation of glucocorticoid levels immediately following injection of 6-OHDA, returning to normal within one to two days. In the BALB/cJ strain, glucocorticoid elevation is seen only after the initial 6-OHDA injection; levels in chronically denervated animals are not different from controls. In the C57B1/6J strain, the increase is seen even with chronically denervated animals. Prior implantation of mice with pellets containing the glucocorticoid receptor antagonist RU-486 does not abrogate denervation-induced increases in cytokine production or proliferation in either strain. In addition to the previously reported increased interleukin (IL)-2 and IL-4 production, there is an increase in IFN-gamma production in the C57B1/6J strain following either acute or chronic denervation. The persistence of denervation-induced changes even when the effect of corticosterone is blocked with RU-486 or diminished with chronic denervation indicates that the changes are driven mainly by a glucocorticoid-independent mechanism.

Animals↗

PubMed1994

Application of the gel shift assay to study the affinity and specificity of anti-DNA autoantibodies.

We have demonstrated that the gel shift assay, a powerful method to study protein.DNA interactions under equilibrium conditions, is both an accurate and precise method to measure the affinity of anti-DNA.DNA immune complexes. One difficulty in performing gel shift assays is disruption of protein.DNA equilibria during the time needed for complexes to enter the gel matrix. However, we have found that highly cross-linked polyacrylamide gels which are known to form non-restrictive matrices, do not perturb anti-DNA.DNA complexes. Using anti-ssDNA BV04-01 as a model antibody, we find good agreement between the dissociation constants (Kd) measured in the gel shift assay using a 5.4% polyacrylamide gel cross-linked with 0.6% (bis)acrylamide, and those obtained previously by fluorescence quenching. Because gel shift assays require only nanogram quantities of analyte and can be performed in several hours, it is well suited for a range of anti-DNA binding studies.

Antibodies, Antinuclear↗

PubMed1994

Aviation pioneers: World War II air evacuation nurses.

During World War II, nurses pioneered a new role for women in the skies. This study of the 1942-1944 Movietonews, the largest of the U.S. newsreel companies with international syndication, identified the exploits of these nurses, compared personal accounts and highlighted flight nurses' contributions to the profession, society, and aviation.

Aviation↗

PubMed1990

Sale of the century: images of nursing in the Movietonews during World War II.

Images of nursing in televised news have been problematic at a time when recruitment of nurses is a critical need. During the World War II years, a massive campaign successfully recruited nurses, and newsreels were a major source of news information. An analysis of two years, 1942 to 1944, of the Movietonews, the largest US newsreel company, identifies images presented during the times, considers those images in a historical context, and proposes successful recruitment strategies that could be useful today. Nursing's scientific base, the great demand for nurses, and a link between public needs and nurses' skill and intelligence are powerful images that should be promulgated in today's news media.

Career Choice↗

PubMedDate not supplied

Inhibition of tumor growth by L-deprenyl involves neural-immune interactions in rats with spontaneously developing mammary tumors.

L-deprenyl, a monoamine oxidase-B inhibitor, has been shown to reverse the age-related decline in sympathetic noradrenergic innervation and immune function in old rats and enhance T cell and NK cell activity in tumor-bearing rats. The objective of the present study was to examine whether deprenyl treatment of old female rats with mammary tumors could augment sympathetic nervous system and immune responses to inhibit the tumor growth. Female Sprague-Dawley rats with spontaneous mammary tumors were administered 0, 2.5 mg, or 5.0 mg/kg body weight (BW)/day deprenyl for i.p. 9 weeks. Tumor diameter, tumor number and body weight were measured throughout the treatment period. At the end of the treatment period, norepinephrine (NE) concentration, interferon-gamma production (IFN-gamma), Con A-induced T lymphocyte proliferation, and percentage of T and B lymphocytes and natural killer cells were measured in the spleen, and the concentrations of monoamines were measured in the medial basal hypothalamus. Relative to saline-treated controls, treatment with deprenyl reduced tumor growth, increased NE concentration, IFN-gamma production and percentage of the CD8+ T lymphocytes in the spleen. In the medial basal hypothalamus, deprenyl treatment increased the concentrations of catecholamines and indoleamine. These results suggest that the anti-tumor effects of deprenyl on spontaneous rat mammary tumors may be achieved via neural-immune signaling in the spleen and medial basal hypothalamus.

Animals↗