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Biomedical subjects

S Schaffer

Publications and source records attributed to S Schaffer.

At least 37 records · Page 2Linked to original sources
PubMed1994

Characteristics of Myocardial Infarction Episodes in Two Distant Communities: From the REGICOR Registry in Girona, Spain and the MITI Registry in Greater Seattle, USA.

Background: The objective of the study is to compare patient characteristics and outcome after myocardial infarction (MI) between two geographically and socially different communities. Methods/Results: The study was designed as an ecological comparison between a 1-year hospital registry of consecutive MIs in Seattle (1,400,000 inhabitants and a predominantly urban and suburban distribution) and nine hospitals in Giroma (500,000 inhabitants in a predominantly rural distribution). Hospitalization rates for MI are higher in Seattle (standardized rates of 2.5/1000 for men and 0.8/1000 for women) than in Girona (1.5/1000 for men and 0.2/1000 for women). In both registries men under age 60 accounted for 45.5% of cases. Women accounted for 25% of all MI episodes in Seattle and for only 16% in Giromi. Treatment with thrombolytic and beta-blocking drugs was twice as common in Seattle hospitals as in Girona. Hospital mortality in tertiary care hospitals was similar in both registries, but mortality in local hospitals (having no coronary care unit) in Giroma was significantly higher than other hospital mortality rates for MI. Conclusions: The higher in-hospital mortality rate may in large part be explained by the absence of a coronary care unit. However, the dispersion of Girona's population and the lack of specific programs to provide emergent specialized care to possible MI patients may also contribute to the higher in-hospital mortality rate in Girona.

Journal Article↗
PubMed1994

Effect of taurine and methionine on sarcoplasmic reticular Ca2+ transport and phospholipid methyltransferase activity.

Perfusion of rat hearts with buffer containing 300 microM L-methionine led to a decrease in Ca(2+)-induced Ca2+ release in sarcoplasmic reticulum (SR) but an increase in calcium-independent Ca2+ release from junctional SR. These effects of L-methionine were not altered by exposure of the hearts to high levels of extracellular taurine, but changes in the size of the intracellular taurine pool appear to modulate calcium transport in SR through two mechanisms. First, millimolar concentrations of taurine can directly promote release of calcium from 45Ca(2+)-loaded junctional SR vesicles. Second, taurine serves as an inhibitor of SR phospholipid methyltransferase, an enzyme that appears to be responsible for methionine-mediated loss in Ca(2+)-induced Ca2+ release activity and promotion of Ca(2+)-independent Ca2+ release. The data imply that modulation of the intracellular taurine pool may affect cellular calcium homeostasis and myocardial contractile function. This may be important in development of the cardiomyopathy linked to taurine deficiency.

Animals↗
PubMed1991

Interaction of taurine with methionine: inhibition of myocardial phospholipid methyltransferase.

Perfusion of isolated, working rat heart with buffer containing 300 microM methionine in the presence of 2.5 U/L insulin led to a 15% decrease in cardiac work and a four-fold decrease in sarcolemmal Na(+)-Ca2+ exchange activity. These effects of methionine were largely prevented by inclusion of 10 mM taurine in the buffer supplemented with methionine and insulin. Taurine also reduced the extent of 3H-methyl group incorporation from radioactive methionine into myocardial phospholipids by approximately 45%. Assays of sarcolemmal phospholipid methyltransferase activity at catalytic sites I, II, and III revealed that taurine inhibited N-methylation activity approximately 30%. The data imply that the ability of taurine to modulate myocardial contraction and calcium transport may be related to taurine-mediated inhibition of phospholipid N-methylation.

Animals↗
PubMed1991

Otitis media in adult trauma patients: incidence and clinical significance.

To determine the incidence and clinical significance of otitis media in traumatized adults requiring intubation, 67 adult trauma patients admitted to a level-I trauma center over a 6-month period who required three or more days of intubation were examined otoscopically for the presence of otitis media. Eleven of these intubated brain-injured patients had otitis and upon examination all were found to have purulent paranasal sinusitis as well. In conclusion, all intubated patients with severe head injuries should be evaluated otoscopically for the presence of otitis and those patients with otitis should be examined for the presence of sinusitis.

Acute Disease↗
PubMed1990

Human papillomavirus. A sexually transmitted disease with carcinogenic potential.

Over the last decade, human papillomavirus (HPV) has been linked with a spectrum of genital disease ranging from latent infection or benign warty growths to neoplasia and carcinoma. The increasing prevalence of HPV and the potential for neoplastic progression mandates that health care providers identify and screen those at high risk for HPV infection and teach strategies for preventing the transmission of this disease. Strategies for diagnosis and treatment vary depending on the anatomic location and/or degree of cellular change provoked by the virus. Although eradication of the virus is not possible, treatment modalities that eradicate abnormal squamous cells have been shown to halt the progression of the neoplastic process. Nursing care of patients with HPV is challenging because of the complex physiological and psychosexual impact of the disease on the patient and on sexual partners. This article discusses the incidence, viral characteristics, oncogenic potential, and treatment strategies for HPV infection as well as associated nursing strategies.

Female↗
PubMed1988

Double-blind controlled trial of the Garren-Edwards gastric bubble: an adjunctive treatment for exogenous obesity.

Since its approval by the Food and Drug Administration in September 1985, the Garren-Edwards gastric bubble has been extensively used as an adjunct to diet and behavioral modification in the treatment of exogenous obesity. In an attempt to evaluate the efficacy of the Garren-Edwards gastric bubble, a double-blind crossover study was undertaken. Ninety patients were randomized into three groups: bubble-sham, sham-bubble, and bubble-bubble in two successive 12-wk periods. Sixty-one patients completed the entire 24-wk study. All groups participated in ongoing diet and behavioral modification therapy in a free-standing obesity program, the members of which were blinded to randomization arms. All patient groups lost weight during this study. The mean cumulative weight loss in pounds at 12 wk was as follows: bubble-sham = 19, sham-bubble = 12, and bubble-bubble = 8; and at 24 wk: bubble-sham = 23, sham-bubble = 16, and bubble-bubble = 18. The mean cumulative change in body mass index (kg/m2) at 12 wk was as follows: bubble-sham = -3.1, sham-bubble = -2.3, and bubble-bubble = -2.9; and at 24 wk: bubble-sham = -3.1, sham-bubble = -3.0, and bubble-bubble = -3.3. Although weight loss occurred more consistently in patients with a Garren-Edwards gastric bubble, there were no significant differences between any of the three groups at 12 or 24 wk with respect to weight loss or change in body mass index. The major part of the weight loss noted during this study occurred during the first 12-wk period, irrespective of therapy (bubble or sham). Side effects observed during this study included gastric erosions (26%), gastric ulcers (14%), small bowel obstruction (2%), Mallory-Weiss tears (11%), and esophageal laceration (1%). We conclude that, in this study, the use of a Garren-Edwards gastric bubble did not result in significantly more weight loss than diet and behavioral modification alone in the management of exogenous obesity, and it may result in significant morbidity.

Adolescent↗
PubMed1983

Nature of behavioral deficits and degree of recovery differ after lesions of dorsal and ventral aspects of rostral cortex.

Bilateral lesions of either the dorsal or the ventral aspects of the rostral half of the cortex in rats both significantly depressed eating, drinking and body weight, but animals with dorsal cortex lesions recovered more quickly and more completely than those with ventral lesions. Furthermore, spontaneous locomotor activity in the open field of animals with ventral cortex, lesions was unaltered relative to this group's preoperative level. On the other hand, relative to their preoperative baseline, the activity of animals with dorsal lesions was significantly depressed during the early postoperative period, and then was significantly elevated during intermediate and late periods. The discussion attempts to interpret these findings on the nature and degree of the locomotor and ingestive behavior deficits resulting from lesions of the dorsal and ventral aspects of the rostral cortex, and the subsequent recovery of behavioral function in light of current electrophysiological, anatomical and behavioral concepts of localization of function within the rat's cortex.

Animals↗
PubMed1976

Epinephrine, cyclic AMP, calcium, and myocardial contractility.

In the first part of this paper, a short review of the literature on the effects of catecholamines, Ca2+, and cyclic AMP on the biochemical, electrical, and mechanical properties of the heart is presented. It is concluded that the effects of epinephrine on activation of glycogenolysis and on the inotropic response of cardiac muscle are both mediated by the combined actions of Ca2+ and cyclic AMP. Since the inotropic response precedes the glycogenolytic response it is evident that increased energy metabolism is a consequence of increased heart work and not a causative factor. The available data suggest that increased tissue cyclic AMP levels resulting from catecholamine stimulation of adenyl cyclase activity alter cardiac mechanics by modulation of the basic calcium flux cycle of the heart. These effects may be mediated by cyclic AMP-stimulated phosphorylation of specific proteins located in the sarcolemma, sarcoplasmic reticulum, and myofilaments via one or more protein kinases, although experimental verfication of the possible relationship between protein phosphorylation and altered Ca2+ binding properties at specific sites in the membranes is at present largely lacking. The increased rate of tension development induced by catecholamines appears to be caused by an increased rate of Ca2+ influx across the sarcolemma during the plateau phase of the action potential, whereas the increased rate of relaxation is probably attributable to an increased rate of sequestration of intracellular Ca2+ by the sarcoplasmic reticulum. In the second part of the paper, data are presented using a working rat heart preparation to illustrate the effect of catecholamines in facilitating Ca2+ entry across the sarcolemma. Decreased left ventricular pressure development induced by addition of ruthenium red or verapamil to inhibit Ca2+ influx was relieved in a concentration-dependent manner by catecholamines. Curves of percentage change of left ventricular pressure against external Ca2+ concentration are presented which show that epinephrine increased the sensitivity of the heart to Ca2+ whereas verapamil decreased it. A half-maximal increase of left ventricular pressure was obtained with 0.6 mM Ca2+ in control hearts, 0.3 mM Ca2+ with epinephrine, and 2.9 mM Ca2+ with verapamil (10(-7)-treated hearts. Verapamil combined with epinephrine at the above concentrations gave a half-miximal increase of left ventricular pressure with 1.3 mM Ca2+. These results are discussed in relation to a model for the Ca2+ flux in the heart.

Adenosine Triphosphate↗
PubMed1976

Development of monoclonal IgA and an apparent IgG in a patient with macroglobulinemia: sharing of individually specific antigenic determinants among IgM, IgA, and IgG.

Patient CM, who initially was diagnosed as having macroglobulinemia (IgM, kappa) was subsequently found to develop a monoclonal IgA(kappa) protein. Rabbit antisera directed against the patient's IgAm and IgM were rendered specific for individual antigenic (ind) determinants. The anti-IgAm and IgM ind sera reacted with both 131I labeled monoclonal proteins in a double antibody radioimmunoassay (RIA). In addition, both monoclonal immunoglobulins inhibited the reaction between labeled immunoglobulin and both ind antisera, and statistical analysis of the data suggested that the shared ind determinants were identical. The IgG fraction of patient CM's serum also contained a component which competed with both monoclonal IgA (CM) and IgM (CM) in the RIA specific for ind determinants. Analysis of serum samples taken over a 2-year period revealed that, in addition to IgM, both the IgA and IgG components possessing the shared ind determinant(s) were present in low concentrations in the earliest sample, although not detected by conventional techniques. The monoclonal IgA and the IgG component were found to increase in concentration over this time interval with a concomitant decrease in IgM. The regulation of immunoglobulin expression with respect to the proposed models of gene organization in antibody-producing cells was discussed.

Antibody-Producing Cells↗