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Biomedical subjects

B Rabinowitz

Publications and source records attributed to B Rabinowitz.

At least 127 records · Page 7Linked to original sources
PubMed1975

Myocardial and plasma levels of adenosine 3':5'-cyclic phosphate. Studies in experimental myocardial ischemia.

Alterations in myocardial and plasma levels of adenosine 3':5'-cyclic phosphate (cyclic AMP) were studied following clamping of the aorta or coronary artery occlusion in 30 dogs. Plasma cyclic APM levels increased markedly after thoracotomy but returned to control levels two hours later. Complete arrest of aortic flow (clamping) induced a significant early increase in the myocardial cyclic AMP levels of all animals studied. No increase was noted following pretreatment with propranolol or sham-occlusion. After localized coronary occlusion, only modest and insignificant changes occurred in plasma cyclic AMP levels in anesthetized animals and also in conscious dogs. The present study suggests that adrenergically mediated changes in tissue cyclic AMP content are an early manifestation of both generalized and local myocardial ischemia, while the plasma cyclic AMP level is a relatively insensitive indicator of small coronary occlusions.

Animals↗
PubMed1975

Alterations in myocardial and plasma cyclic adenosine monophosphate in experimental myocardial ischemia.

Alterations in myocardial and plasma cyclic adenosine monophosphate (cyclic AMP) levels were studied following clamping of the aorta or coronary artery occlusion in 30 dogs. Plasma cyclic AMP levels increased markedly after thoracotomy but returned to control levels 2 hr later. Complete arrest of aortic flow (clamping) induced a significant early increase in the myocardial cyclic AMP levels of all animals studied. No increase was noted following pretreatment with propranolol or sham occlusion. Localized coronary occlusion tended to increase plasma cAMP levels in anesthetized animals and also in concious dogs. The present study suggests that adrenergically mediated changes in tissue and plasma cyclic AMP content are early manifestations of both generalized and local myocardial ischemia and tend to reflect the magnitude of the insult.

Animals↗
PubMed1968

Pulp therapy.

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Cresols↗
PubMedDate not supplied

Prostaglandins and the antiarrhythmic effect of preconditioning in the isolated rat heart.

Our study evaluated the relationship between the endogenous production of prostacyclin and the antiarrhythmic effect of ischemic preconditioning against ischemic and reperfusion-induced tachyarrhythmia. Langendorff perfused rat hearts underwent 30 min regional ischemia with reperfusion. Preconditioning was induced by a single episode of 5 min ischemia and 15 min reperfusion. Prostaglandin 6-keto F1 alpha (a stable metabolite of prostacyclin) was determined in the coronary effluent. In the control group the incidence of tachyarrhythmia was 31% during ischemia and 67% during reperfusion. Preconditioning did not affect ischemic arrhythmias but attenuated arrhythmias a reperfusion (8%, p < 0.01) and was associated with increased release of prostacyclin prior to reperfusion. Aspirin abolished the antiarrhythmic effect of preconditioning against reperfusion tachyarrhythmias. However, no relationship was found between suppression of prostacyclin production and the occurrence of arrhythmia in individual hearts. Thus, our findings suggest that metabolites of arachidonic acid via the cyclooxygenase pathway are involved in the protective effect of ischemic preconditioning against reperfusion-induced tachyarrhythmias.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

In vivo assessment of the inotropic and toxic effects of oxidized ouabain.

Oxidized ouabain, a product of the oxidative cleavage of the rhamnose ring in ouabain has been found to have a higher inotropic toxic ratio in cultured cardiac myocytes. The purpose of our study was to evaluate the efficacy and toxicity of oxidized ouabain in comparison with ouabain in intact animals. Drugs were infused to healthy cats; the positive inotropic effect, and the time-course of development of arrhythmia were followed and recorded until death. Oxidized ouabain was associated with a higher increase in arterial blood pressure, a mean increase of 41 +/- 19% as compared with 21 +/- 8% in the ouabain group (p < 0.10). There were no significant differences in maximal increases of dP/dt or dP/dt/P (65 +/- 29%, 28 +/- 10% for oxidized ouabain and 49 +/- 16%, 27 +/- 11% for ouabain, respectively). The mean doses causing persistent arrhythmia (toxic dose) were 93 +/- 23 micrograms/kg of oxidized ouabain vs 39 +/- 14 micrograms/kg of ouabain. Lethal arrhythmias were produced by 215 +/- 46 micrograms/kg of oxidized ouabain and 62 +/- 16 micrograms/kg of ouabain. The ratio of toxic to lethal doses was 0.62 +/- 0.11 for ouabain vs 0.45 +/- 0.09 for oxidized ouabain (p < 0.05), but the inotropic to toxic dose ratios were not different. We conclude that oxidized ouabain acts similarly to the known cardiac glycosides in doses which produce inotropic effects in cats, has a lower potency as compared to ouabain, and appears to have a more benign course of intoxication.

Animals↗
PubMedDate not supplied

Investigation of antibiotic prophylaxis usage for vascular and nonvascular interventional procedures.

PURPOSE: To investigate current antibiotic prophylactic usage for arteriography, angioplasty, vascular stent placement, transjugular intrahepatic portosystemic shunt placement (TIPS), tunneled-port placement, inferior vena cava (IVC) filter placement, biliary drainage, genitourinary drainage, abdominal drainage, and enteral tube placement with an aim to better clarify indications and regimens for prophylaxis. METHODS: A questionnaire regarding antibiotic prophylactic usage was sent to 2,039 members of the Society of Cardiovascular and Interventional Radiology (SCVIR). There were 401 respondents. Replies were evaluated for frequency and indications of prophylaxis, specific prophylaxis used, and clarity of indications for prophylaxis. RESULTS: A majority of responders never used prophylaxis for arteriography, angioplasty, vascular stent placement, IVC filter placement, abdominal drainage, and enteral tube placement. Infective complication rates from nonusage ranged between 1% and 15%. Approximately 45% always used prophylaxis for tunneled-port placement and TIPS with a 13%-16% infective complication rate among nonusers. In contrast, a majority of responders always used prophylaxis for biliary and genitourinary drainage, with a 40%-58% infective complication rate in nonusers. More than 70% of responders believed that the indications for prophylaxis were not clear for arteriography, angioplasty, vascular stent placement, tunneled-port placement, TIPS, IVC filter placement, and enteral tube placement, and in contrast, that the indications for prophylaxis for biliary and genitourinary drainage were clear. Fifty-one percent of responders believed that indications for prophylaxis for abdominal drainage were clear. CONCLUSIONS: Indications for antibiotic prophylaxis are not clear to interventionalists for a large number of vascular and nonvascular interventional procedures. Prophylaxis appears unnecessary for routine arteriography, angioplasty, IVC filter placement, vascular stent placement, or enterostomy tube placement. Antibiotic prophylaxis is warranted for TIPS and tunneled-port placement. Conversely, indications for antibiotic prophylaxis are clear to interventionalists for biliary and genitourinary drainage procedures. Routine prophylaxis remains warranted for both.

Antibiotic Prophylaxis↗