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190 results on '"Weintraub, Ronald"'

1. Mitral valve repair and replacement in northern New England

Author

Nowicki, Edward R., Weintraub, Ronald W., Birkmeyer, Nancy J., Sanders, John H., Dacey, Lawrence J., Lahey, Stephen J., Leavitt, Bruce, Clough, Robert A., Quinn, Reed D., and O'Connor, Gerald T.

Subjects
Clinical trials -- Practice, Mitral valve stenosis -- Research, Mitral valve stenosis -- Care and treatment, Diagnosis -- Evaluation, Health
Published
2003

4. Adrenergic regulation of coronary microcirculation after extracorporeal circulation and crystalloid cardioplegia

Author

Wang, Steven Y., Friedman, Menachem, Johnson, Robert G., Weintraub, Ronald M., and Sellke, Frank W.

Subjects
Epinephrine -- Receptors, Coronary arteries -- Research, Cardiopulmonary bypass -- Analysis, Biological sciences
Abstract

Analysis of effects of cardioplegic arrest under cardiopulmonary bypass (CPB) conditions on the adrenoreceptor-mediated responses to coronary resistance arteries in pigs reveals that hyperkalemic cardioplegia causes an abnormality in the beta-adrenoceptor-Gs protein-adenylate cyclase pathway in the coronary microvessels. Cardioplegic arrest reduces the isoproterenol-, forskolin-, adenosine- and NaF-induced relaxation of precontracted microvessels. Cardioplegic arrest also reduces reperfusion during the induction of abnormality in the pathway.

Published
1994

12. Cardiopulmonary bypass, myocardial management, and support techniques Changes in autonomic response of the cerebral circulation after normothermic extracorporeal circulation

Author

Sellke, Frank W., Wang, Steven Y., Stamler, Alon, Johnson, Robert G., Cohn, William E., and Weintraub, Ronald M.

Subjects
Coronary artery bypass -- Methods, Adenylate cyclase -- Methods, Cyanides -- Methods, Guanylate cyclase -- Methods, Sodium nitroferricyanide -- Methods, Blood vessels -- Dilatation, Blood vessels -- Methods, Health
Abstract

Byline: Frank W. Sellke, Steven Y. Wang, Alon Stamler, Robert G. Johnson, William E. Cohn, Ronald M. Weintraub Abstract: Patients who undergo cardiopulmonary bypass frequently have neuropsychologic dysfunction. This study was undertaken to determine whether altered cerebral perfusion and vascular responses may in part lead to these neuropsychologic changes. Pigs were placed on normothermic cardiopulmonary bypass for 2 hours. Basal cerebral blood flow and in vivo responses to administration by internal carotid artery of neuronally released vasoactive substances were evaluated before and 5 to 15 minutes after termination of cardiopulmonary bypass. Another group of pigs were placed on cardiopulmonary bypass for 2 hours and then perfused off bypass for 1 additional hour. In vitro responses of cerebral arterial microvessels (100 to 175 [mu]m) from both groups were examined in a pressurized (40 mm Hg) no-flow state with videomicroscopy. Vessels from uninstrumented pigs served as control preparations for in vitro studies. Cerebrovascular resistance and cerebral perfusion were maintained constant during cardiopulmonary bypass and after separation from bypass. The internal carotid artery infusion of acetylcholine (cholinergic agonist) caused increased internal carotid artery blood flow before cardiopulmonary bypass but decreased blood flow after cardiopulmonary bypass. After 2 hours of cardiopulmonary bypass, the increase in internal carotid artery blood flow induced by isoproterenol (a [beta]-adrenoceptor agonist) was reduced, whereas the response to sodium nitroprusside (a guanylate cyclase activator) was unchanged. In vitro acetylcholine-induced microvascular vasodilation was converted to a contractile response and isoproterenol elicited less relaxation after 2 hours of cardiopulmonary bypass. One hour of cerebral perfusion after cardiopulmonary bypass caused a further reduction in isoproterenol-induced relaxation but had no further effect on the cholinergically mediated response. In vitro relaxation responses to sodium nitroprusside and forskolin (an adenylate cyclase activator) were similar in all experimental groups, suggesting that second-messenger mechanisms remain intact after normothermic cardiopulmonary bypass. In conclusion, basal cerebrovascular resistance and internal carotid artery blood flow are maintained if the systemic circulation and pressure are supported with fluid administration after cardiopulmonary bypass. Agonist-induced vasodilation of cerebral microvessels to cholinergic and [beta]-adrenoceptor stimulation are selectively impaired after normothermic cardiopulmonary bypass, whereas second-messenger mechanisms remain intact. (J Thorac Cardiovasc Surg 1996;112:450-61) Article History: Received 26 July 1995; Accepted 3 October 1995 Article Note: (footnote) [star] From the Division of Cardiothoracic Surgery, Beth Israel Hospital and Harvard Medical School, Boston, Mass., [star][star] Supported by NIH grant HL 46716 and a grant from the American Heart Association, Massachusetts Affiliate., a Address for reprints: Frank W. Sellke, MD, Division of Cardiothoracic Surgery, Beth Israel Hospital, Dana 905, 330 Brookline Ave., Boston, MA 02215., aa 0022-5223/96 $5.00 + 0, acents 12/1/69673

Published
1996

15. Duration of cardiopulmonary bypass and risk of perioperative stroke in coronary artery bypass surgery operations

Author

Weintraub, Ronald M., primary, Likosky, Donald S., additional, Ross, Cathy S., additional, Leavitt, Bruce J., additional, Marrin, Charles A., additional, Malenka, David J., additional, Caplan, Louis R., additional, Baribeau, Yvon R., additional, Charlesworth, David C., additional, Hernandez, Felix, additional, and O'Connor, Gerald T., additional

Published
2003
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22. CABG after successful PTCA: A case-control study

Author

Johnson, Robert G., primary, Sirois, Cheryl, additional, Watkins, James F., additional, Thurer, Robert L., additional, Sellke, Frank W., additional, Cohn, William E., additional, Kuntz, Richard E., additional, and Weintraub, Ronald M., additional

Published
1995
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47. Mechanisms causing coronary microvascular dysfunction following crystalloid cardioplegia and reperfusion.

Author

Sellke, Frank W, Friedman, Menachem, Dai, Hai Bin, Shafique, Tajammul, Schoen, Frederick J, Weintraub, Ronald M, and Johnson, Robert G

Abstract

Objective: The aim was to examine the mechanisms of coronary microvascular dysfunction during cardiopulmonary bypass and ischaemic arrest using a crystalloid cardioplegic solution. Methods: Porcine hearts were arrested with cold hyperkalaemic (K+=25 mmol·litre−1) cardioplegic solution for 1 h during cardiopulmonary bypass and then reperfused for 1 h. Selected hearts were arrested but not reperfused. Coronary vessels of non-instrumented pigs were used as controls. In vitro vascular responses of subepicardial and subendocardial arterioles were examined in a pressurised (40 mm Hg) no flow state with video microscopy. Results: Following 1 h of ischaemic cardioplegia, endothelium dependent relaxations of epicardial arterioles to the receptor mediated agent ADP and the non-receptor-mediated agent calcium ionophore A23187 were moderately reduced, and the contractile responses to KCl or the thromboxane A2 analogue U46619 were reduced compared to responses of vessels from control animals. After 1 h of reperfusion, U46619 caused contraction greater than control values, while contraction to KCl and endothelium dependent relaxations to ADP or A23187 were further reduced. Responses of endocardial microvessels to serotonin were slightly more affected by cardioplegia and reperfusion than were epicardial vessels, while the effect on responses of epicardial and endocardial vessels to bradykinin or A23187 were similar. Endothelium independent relaxation to sodium nitroprusside was not altered in any of the experimental groups. The addition of manganese superoxide dismutase to the cardioplegic solution markedly preserved endothelium dependent responses to ADP and A23187 and contractile response to U46619, compared to the responses of vessels from the plain crystalloid cardioplegia group, but had no effect on relaxation to sodium nitroprusside or on contraction to KCl. Five hours of normokalaemic hypothermia (5-10°C) in Krebs buffer had minimal effect on vasodilator responses. Electron microscopy revealed preserved endothelial and smooth muscle cell structure, and focal mononuclear leucocyte-endothelium adherence following cardioplegic arrest and reperfusion. Conclusions: Ischaemic cardioplegia-reperfusion induced endothelium dependent and direct smooth muscle microvascular dysfunction is at least partially mediated by prolonged exposure of vessels to hyperkalaemia and to the generation of oxygen derived free radicals. Leucocytes probably mediate injury during reperfusion, while hypothermia has minimal effect on recovery of vasomotor function.Cardiovascular Research 1993;27:1925-1932 [ABSTRACT FROM PUBLISHER]

Published
1993

49. Readers Report.

Author

Weintraub, Ronald, Lieberman, Nancy A., Slocum, Ralph, Warren, Marc J., Smith, Ken, Posner, Russell, Rothschild, Alan, and Wineberg, David

Subjects
LETTERS to the editor, STUDENTS, PETROLEUM industry, EDUCATION
Abstract

Presents several letters to the editor pertaining to articles in previous issues. "Dynasty in distress," which discusses the Stern family; "Why is oil so expensive-again?" that reports on the price of oil in the United States; "Social Issues: Education," which focuses on college tuition and its effect on students in science; "The Corporation," which describes the many businesses in the town of Columbus, Georgia; "So where are the jobs?" that focuses on why jobs are not reappearing.

Published
2004

50. Economics of elective coronary revascularization Comparison of costs and charges for conventional angioplasty, directional atherectomy, stenting and bypass surgery

Author

Cohen, David J., Breall, Jeffrey A., Ho, Kalon K.L., Weintraub, Ronald M., Kuntz, Richard E., Weinstein, Milton C., and Baim, Donald S.

Abstract

Objectives. This study was designed to evaluate more closely the true in-hospital costs of elective revascularization by directional coronary atherectomy and intracoronary stenting and to compare these costs with those of the traditional revascularization alternative (i.e., conventional balloon angioplasty and coronary artery bypass surgery).Background. Previous studies have suggested that total hospital charges for directional coronary atherectomy or intracoronary stenting are significantly higher than those for conventional angioplasty. However, hospital charges do not necessarily reflect true economic costs, and their use may provide misleading data with regard to cost-effectiveness.Methods. We analyzed in-hospital charges from the itemized hospital accounts of 300 patients undergoing elective angioplasty, directional atherectomy, Palmaz-Schatz coronary stenting or bypass surgery between January 1, 1990 and December 31, 1991. Costs were then derived by adjusting itemized patient accounts for department-specific cost/charge ratios. Catheterization laboratory costs were based on actual resource consumption, and daily room costs were adjusted for the intensity of nursing services provided.Results. Length of hospital stay was similar for atherectomy (2.3 ± 1.5 days) and conventional angioplasty (2.6 ± 1.7 days) but significantly longer for stenting (5.5 ± 2.6 days, p < 0.05). Total costs were also significantly higher for coronary stenting ($7,878 ± $3,270, median $6,699, p < 0.05) than for angioplasty ($5,396 ± $2,829, median $4,753) or atherectomy ($5,726 ± $2,716, median $4,986). However, length of stay, resource consumption (laboratory and radiologic testing, drugs, blood products, for example) and total costs for bypass surgery were still greater than for any of the percutaneous interventional procedures.Conclusions. In contrast to previous studies utilizing only hospital charges, the in-hospital costsof angioplasty and directional coronary atherectomy were similar. Although the cost of coronary stenting was approximately $2,500 higher than that of conventional angioplasty, the magnitude of this difference was smaller than the $6,300 increment previously suggested on the basis of analysis of hospital charges. These findings reflect the inherent discrepancies between cost-based and charge-based methodologies and may have important implications for future studies evaluating the relative cost-effectiveness of newer coronary interventions.

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