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Biomedical subjects

B Rabinowitz

Publications and source records attributed to B Rabinowitz.

At least 109 records · Page 6Linked to original sources

Mitral valve prolapse. Quantitative analysis and long-term follow-up.

Forty-two patients with systolic posterior motion of the mitral valve on M-mode echocardiogram were reevaluated after a mean clinical follow-up of 6.7 years and an echocardiographic follow-up of 5.1 years. A new method for quantitation of mitral valve prolapse (MVP) is presented. A straight line (A) was drawn connecting the site of posterior leaflet motion with the D point of the subsequent diastole. A vertical line (B), termed "the degree of MVP," was drawn from the site of maximal MVP to line A. The degree of MVP was then correlated with various clinical and ECG parameters and with the presence of complications. Measurements could be taken in 21 patients; the mean degree of MVP increased from 5.9 +/- 2.1 to 7.1 +/- 2.9 mm (P less than 0.01), and mean left atrial size increased from 3.0 +/- 0.5 to 3.5 +/- 0.8 cm (P less than 0.01). No correlation was found between the degree of MVP and symptoms, auscultatory findings or the presence of complications. There were no deaths and in none was life-threatening arrhythmia documented. The complications we encountered were endocarditis in five patients, transient ischemic attacks in two and cardiac arrest during surgery in one. We conclude that 1) the degree of MVP can be measured by M-mode echocardiography; 2) there seems to be no correlation between the degree of MVP and the patient's clinical state; 3) complications in MVP are rather frequent; and 4) left atrial size and degree of MVP tend to increase with time, which may indicate a progressive nature of the disease.

Adolescent↗

Selective conservative management of penetrating abdominal wounds: a prospective study.

This is a prospective study comprising 156 cases of abdominal stab wounds. The cases were assessed exclusively on clinical grounds: 37.18 per cent of them were treated conservatively without any mortality and minimal complications. Shock, blood on abdominal paracentesis, omentum protruding through the wound, and radiologically free air under the diaphragm, were not absolute indications for surgery. Alcohol consumption did not interfere with the clinical assessment. Of all 130 cases with proved peritoneal penetration, 28.46 per cent had no significant visceral injury. The incidence of negative laparotomies was 7.0 per cent.

Abdominal Injuries↗

Excess mortality and morbidity associated with right bundle branch and left anterior fascicular block.

Excess mortality and morbidity associated with right bundle branch and left anterior fascicular block were evaluated in 108 patients with block (age 74 +/- 10 years, 69% male) and 108 age- and sex-matched control patients with normal conduction. Clinical characteristics were similar initially except for more congestive heart failure in patients with block. Life table analysis revealed a higher 12 year mortality with block, even after omitting patients with moderate or severe congestive heart failure (risk ratio 1.47, p less than 0.05). Compared with control subjects, the group of patients with block had more sudden death and deaths of unknown cause, but a similar number of noncardiac and diagnosed cardiac deaths. More patients with block developed new second and third degree atrioventricular block or new overt coronary artery disease, but this finding did not support prophylactic pacing in asymptomatic patients. The importance of internal controls in assessing the natural history of clinical and electrocardiographic abnormalities is emphasized.

Adult↗

Intravenous isosorbide dinitrate in patients with refractory pump failure and acute myocardial infarction.

We studied the hemodynamic effects of isosorbide dinitrate administered by continuous i.v. infusion to 22 patients with chronic refractory pump failure and 18 with pump failure due to acute myocardial infarction. In patients with severe pump failure, i.v. ISDN markedly decreased pulmonary capillary wedge pressure (p less than 0.001), moderately increased cardiac output (p less than 0.01), and decreased systemic vascular resistance (SVR) (p less than 0.001). There were no deleterious effects on arterial pressure and heart rate. The effects obtained in acute and chronic left ventricular failure were similar. Patients with initial SVR levels lower than 1500 dyn-sec-cm-5 did not significantly increase their cardiac output (p less than 0.005). Cardiac output increased more than 25% only in patients with initial high SVR levels (greater than 2000 dyn-sec-cm(-)5). Positive correlations were found between high SVR and elevated plasma catecholamines (r = 0.53, p less than 0.05) and between the initial SVR and initial heart rate (r = 0.70, p less than 0.01). The i.v. administration of isosorbide dinitrate appears to be an efficient therapy, particularly in selected patients with ischemic pump failure.

Catecholamines↗

Chronic pancreatitis and the hepatobiliary system.

Alcohol-induced chronic pancreatitis involving the head of pancreas may have profound effects on the hepatobiliary system. The natural history, complications, and management of the syndrome are presented, using selected cases to emphasize important features. Chronic pancreatitis can cause mechanical obstruction to both the distal common bile duct and the proximal pancreatic duct. In the common bile duct this will result in proximal dilatation above the stenosis with bile stasis. Possible sequelae are ascending cholangitis, cholecystitis, biliary calculi formation, and secondary biliary cirrhosis. The mechanical effects of stricture of the proximal pancreatic duct may exacerbate pancreatic dysfunction. The clinicopathological spectrum of chronic pancreatitis with biliary obstruction encompasses three clinical types--"transient," "recurrent", and "persistent." The widespread effects of the syndrome are evident from the involvement of pancreas, proximal pancreatic duct, papilla of Vater, liver, peripheral biliary tree, common bile duct, gallbladder, and reticuloendothelial system. Essential to management is surgery which should be considered when there is objective evidence of obstruction to the common bile duct. Choledochoduodenostomy is the preferred type of operation. If dilatation is mild and jaundice transient, conservative therapy with careful observation is advocated.

Adult↗

Use of labetalol in hypertensive patients during discontinuation of clonidine therapy.

Eleven hypertensive patients in whom clonidine therapy had to be discontinued, were treated prophylactically with labetalol, in order to avoid a possible hypertensive crisis. Most of the known side effects, which are consistent with the withdrawal phenomenon were observed, e.g. tremor, insomnia and apprehension, but headaches and flushing did not occur. Blood pressure levels remained unchanged, despite up to a 20-fold increase in plasma catecholamines. The lack of change in serial measurements of plasma cyclic AMP level appears to indicate that adequate adrenergic blockade was induced by labetalol. Since labetalol is a potent anti-hypertensive drug, and is also effective in avoiding a possible hypertensive crisis due to withdrawal of clonidine, we propose to use it as the drug of choice whenever discontinuation of clonidine therapy is indicated.

Adult↗

Steady-state serum quinidine concentration: role in prophylactic therapy following acute myocardial infarction.

Steady-state serum quinidine concentrations were monitored in 24 patients with acute myocardial infarction who were on a 1,300-mg daily dosing regimen. Mean serum concentrations spanned the therapeutic range, from 2 to 6 microgram/ml in 21 patients. In no patient was the level of 7 microgram/ml exceeded. Mean levels were similar in patients with congestive heart failure [3.6 +/- 1.5 (SD) microgram/ml] as in those free of failure (3.2 +/- 1.3 microgram/ml), and did not vary with impairment of renal function. There was a significant correlation between mean individual serum quinidine concentrations and the rate-normalized QT interval prolongation (r = 0.54, P less than 0.01); however, variability of the response was high. Variability of the mean serum quinidine levels among individuals was 41%. Variability within individual patients was only 18%. In the individual patient receiving prophylactic oral quinidine therapy, monitoring serum quinidine levels appears to be an accurate, reproducible and pharmacologically significant guideline to therapy.

Adult↗

Isoenzymes of creatine phosphokinase in acute myocardial infarction.

Serial determinations of creatine phosphokinase (CPK) isoenzymes were performed in 400 patients with definite acute myocardial infarction (AMI). The findings were correlated with the clinical course and the findings in another 300 cases of increased CPK levels. MB-CPK, the cardiac fraction, was present in all 400 cases of AMI and in only 5 cases of the 300 patients with high CPK due to causes other than AMI. Based on the magnitude and time course of the total CPK in relation to the MB-CPK, five different patterns are described which correlate with the clinical course. Our findings thus suggest that the determination of CPK isoenzymes can be a most helpful diagnostic tool in the care of the cardiac patient.

Acute Disease↗

Positive inotropic effects of methoxamine: evidence for alpha-adrenergic receptors in ventricular myocardium.

The present study was undertaken to evaluate the effects of methoxamine on force development and adenyl cyclase activity in cat ventricular myocardium. Methoxamine produced a dose-related increase in force development of isometrically contracting cat papillary muscles. The positive inotropic effects of methoxamine were not altered by beta-adrenergic blockade (propranolol), or catecholamine depletion by prior reserpinization, but were completely prevented by alpha-adrenergic blockade (phentolamine or ergotamine). Neither ergotamine, phentolamine, nor methoxamine had any direct effects on adenyl cyclase activity. Phentolamine did not attenuate the increase in force development produced by paired electrical stimulation, suggesting that it does not block the entry of calcium into the muscle. In summary, methoxamine produced a dose-related increase in force development of the cat papillary muscle that was selectively blocked by alpha-adrenergic receptors in ventricular myocardium.

Adenylyl Cyclases↗