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Biomedical subjects

M A Silver

Publications and source records attributed to M A Silver.

At least 37 records · Page 2Linked to original sources
PubMed1993

Beneficial effects of metoprolol in idiopathic dilated cardiomyopathy. Metoprolol in Dilated Cardiomyopathy (MDC) Trial Study Group.

Several small studies have suggested beneficial effects of long-term beta-blocker treatment in idiopathic dilated cardiomyopathy. Our large multicentre study aimed to find out whether metoprolol improves overall survival and morbidity in this disorder. 383 subjects with heart failure from idiopathic dilated cardiomyopathy (ejection fraction < 0.40) were randomly assigned placebo or metoprolol. 94% were in New York Heart Association functional classes II and III, and 80% were receiving background treatment. A test dose of metoprolol (5 mg twice daily) was given for 2-7 days; those tolerating this dose (96%) entered randomisation. Study medication was increased slowly from 10 mg to 100-150 mg daily. There were 34% (95% CI -6 to 62%, p = 0.058) fewer primary endpoints in the metoprolol than the placebo group; 2 and 19 patients, respectively, deteriorated to the point of needing transplantation and 23 and 19 died. The change in ejection fraction from baseline to 12 months was significantly greater with metoprolol than with placebo (0.13 vs 0.06, p < 0.0001). Pulmonary capillary wedge pressure decreased more from baseline to 12 months with metoprolol than with placebo (5 vs 2 mm Hg, p = 0.06). Exercise time at 12 months was significantly greater (p = 0.046) in metoprolol-treated than in placebo-treated patients. In patients with idiopathic dilated cardiomyopathy, treatment with metoprolol prevented clinical deterioration, improved symptoms and cardiac function, and was well tolerated.

Adolescent↗
PubMed1990

Left ventricular free wall rupture following acute myocardial infarction and cardiac amyloid.

A 74-year-old man died of left ventricular free wall rupture 6 days following an acute inferoposterior wall myocardial infarction. His hospital course was complicated by pump failure which proved resistant to inotropic support, diuresis, and percutaneous transluminal coronary angioplasty. At necropsy, extensive amyloid deposition was noted. This case constitutes an unusual clinical setting for myocardial rupture because of the severity of systolic left ventricular dysfunction as well as cardiac amyloidosis.

Aged↗
PubMed1990

Reactive and reparative fibrillar collagen remodelling in the hypertrophied rat left ventricle: two experimental models of myocardial fibrosis.

STUDY OBJECTIVE: The aim was to compare the temporal sequence and structural relationship between perivascular and interstitial fibrosis and microscopic scarring seen in the left ventricle in response to either a transient or sustained stimulus to fibrosis. DESIGN: In 72 male Wistar rats (250-350 g) the transient stimulus model was based on the administration of isoprenaline (500 micrograms.kg-1) while the sustained stimulus model was produced by abdominal aortic banding with right renal artery constriction. Serial sections of myocardium were examined and compared at 4 and 12 weeks in each model and to corresponding controls. EXPERIMENTAL MATERIAL: The collagen specific stain, Sirius Red F3BA, was used to determine collagen volume fraction and the fibrillar nature of the fibrous tissue response seen by light microscopy. MEASUREMENTS AND MAIN RESULTS: Following isoprenaline a stable reparative fibrosis of the endomyocardium and increase in collagen volume fraction was seen without an interstitial or perivascular fibrosis of the non-involved myocardium. In unilateral renal ischemia, on the other hand, a progressive perivascular fibrosis was evident throughout the myocardium and from which fibrillar collagen extended into the extracellular space between muscle bundles creating an interstitial fibrosis; microscopic scarring of the endomyocardium became evident at 12 weeks. CONCLUSIONS: The reactive perivascular fibrosis of intramyocardial coronary arteries seen in renovascular hypertension is a progressive process that leads to an interstitial fibrosis and eventual microscopic scarring. In contrast, the endomyocardial scarring that follows isoprenaline induced myocyte necrosis is stable and intramural vessels in remote regions are not involved.

Animals↗
PubMed1990

Fibrillar collagen and remodeling of dilated canine left ventricle.

To test the hypothesis that in the failing volume-overloaded ventricle, the extracellular matrix and fibrillar collagen in particular are major determinants of the architectural remodeling of the myocardium, this histopathological study of the dilated, postmortem canine left ventricle secondary to rapid ventricular pacing or aortocaval fistula was undertaken. Using the picrosirius-polarization technique to enhance collagen birefringence, we sought to examine the structural integrity of the collagen matrix and interstitium. In the dilated failing ventricle secondary to rapid pacing, we found 1) interstitial edema and a disruption or disappearance of collagen fibers that were apparent within 6 hours of pacing, persisted for weeks, and subsequently were associated with muscle fiber disorganization within the endomyocardium, 2) interstitial fibrosis that was present in the midwall and epimyocardium with chronic pacing, and 3) an early remodeling of intramyocardial coronary arteries that included medial swelling with smooth muscle degeneration followed by proliferative lesions involving fibroblasts and a subsequent perivascular and medial fibrosis. Many of these findings were still evident 48 hours after pacing had been discontinued. In contrast, the collagen matrix and interstitium seen with ventricular dilatation secondary to the circulatory overload that accompanies an aortocaval fistula were indistinguishable from that in sham-operated controls. Thus, we conclude that unlike the chamber enlargement and preserved ventricular function that accompany an aortocaval fistula, ventricular dilatation and failure caused by rapid pacing are based on an architectural remodeling of the myocardium. This structural dilatation involves the extracellular matrix and interstitium and appears to be related to altered permeability of intramyocardial coronary arteries. The mechanism or mechanisms involved in the pathogenesis of myocardial remodeling with rapid ventricular pacing require further investigation.

Animals↗
PubMed1990

Critical factors in the professional development of the psychiatrist-administrator.

A questionnaire was sent to 244 psychiatrist-administrators from the metropolitan New York City area to assess the actual and perceived effects of five factors--personality traits, clinical psychiatric training, formal training in administration, administrative experience, and a mentor relationship--on their professional development. The results, based on 200 completed questionnaires, revealed a discrepancy between the respondents' actual and ideal experiences in the areas of the mentor relationship and formal administrative training. The authors recommend structural changes in training programs to attract psychiatrists to administrative careers and to enhance their training and professional development.

Adult↗
PubMed1990

Leiomyoma of a digital artery.

Benign, soft-tissue masses of the hand are common. A vascular leiomyoma is an unusual tumor of smooth-muscle origin. In a 62-year-old man, the tumor arose from within a digital artery. Persistent symptoms prompted an excisional biopsy, requiring resection of a portion of the artery. Adequate collateral circulation preempted the need for a vascular graft. Vascular repair or grafting may be necessary if collateral circulation is not adequate.

Arteries↗
PubMed1989

The making of the psychiatrist-executive.

The authors reviewed the literature on the factors influencing the development of psychiatrist-executives. The results indicate that personality traits, clinical psychiatry training, training in administration, mentors, and administrative experience have an impact on the making of the psychiatrist-executive. On the basis of these findings, the authors make recommendations for further research.

Career Choice↗
PubMed1989

Predictors of late acute orthotopic heart transplant rejection.

To identify predictors of late acute rejection after orthotopic heart transplantation (OHT), 53 patients who received transplants between March 1984 and March 1987 and who survived at least 1 year postoperatively were followed up for 402-1,151 days (mean, 841 days). Fourteen patients experienced 22 moderate or severe rejection episodes more than 1 year after OHT (LR); 39 were nonrejectors (NR). Twelve of 14 (86%) LR and only 14 of 39 (36%) NR had two or more moderate or severe rejection episodes within the first year after OHT (p less than 0.001). The LR had significantly higher numbers of infections more than 1 year after OHT (2.0 vs. 0.9; p less than 0.05). Nine of 22 (40%) late acute rejection episodes followed within 1 month of infection. Human leukocyte antigen reactivity before OHT, follow-up hemodynamics, length of survival, incidence of diabetes mellitus, coronary artery disease 1 year after OHT, mean cyclosporine levels, and mean daily prednisone doses were similar in LR and NR patients. We conclude that 1) OHT recipients with two or more moderate or severe rejection episodes in the first year after OHT are at higher risk of developing late acute rejection and may require closer long-term rejection surveillance and more aggressive maintenance immunosuppression and 2) the possible relation between infection and subsequent acute rejection episodes in OHT recipients requires further investigation.

Adult↗
PubMed1988

The functional anatomy of the human coronary sinus.

The human coronary sinus is an important part of the cardiac venous system that serves as an anatomic landmark as well as a conduit for diagnostic and therapeutic procedures. We studied 50 human coronary sinuses of hearts of normal and increased cardiac weight in order to ascertain various functional anatomic features of the coronary sinus and differences between hearts of normal and increased weight. In the hearts of normal weight (195 to 300 gm) the Thebesian valve covered the ostium of the coronary sinus an average of 41%, with complete coverage in 20%. The valve of Vieussens covered the origin of the coronary sinus an average of 59%. The average volume of the coronary sinus was 1.26 +/- 0.45 cc. In hearts of increased weight (365 to 675 gm), the Thebesian valve covered the ostium an average of 26% and the valve of Vieussens covered the origin of the coronary sinus an average of 56.5%. The average volume of the coronary sinus was increased to 1.76 +/- 0.73 cc (p less than 0.005). Thus knowledge of these functional anatomic features and the differences in hearts of increased cardiac weight allows for better utilization of the human coronary sinus for diagnostic and therapeutic purposes.

Adult↗
PubMed1988

Psychiatrist-executive management styles: nature or nurture?

The authors studied the management styles of the 11 directors of psychiatry in municipal general hospitals in New York City. The Lead-Self Scale and the Lead-Other Scale were used. The directors' Lead-Self Scale scores were compared with those of 11 psychiatric residents. Results show that the directors had a high task/high relationship primary style and a high relationship/low task secondary style. Psychiatric residents revealed a less differentiated pattern of self-perceived management style. The authors speculate about the effects of experience, training, role models, and personality traits on management styles and suggest areas for further research.

Administrative Personnel↗
PubMed1988

Reversal of recalcitrant cardiac allograft rejection with methotrexate.

Refractory cardiac transplant rejection is a major therapeutic dilemma. The effectiveness of methotrexate (MTX) in autoimmune diseases prompted us to explore its efficacy in 10 cardiac transplant recipients, aged 20-53 years (39 +/- 13 years; mean +/- SD), with biopsy evidence of drug-refractory cardiac allograft rejection. Nine cardiac transplant recipients were maintained on triple antirejection therapy (cyclosporine, azathioprine, and prednisone), and the remaining recipient was maintained on cyclosporine and prednisone. Rejection episodes treated with MTX occurred 20-422 days (165 +/- 137 days) after transplantation and were the sixth episode of rejection for one recipient, the third for four recipients, the second for four recipients, and the first for one recipient. Before MTX administration, cardiac allograft rejection persisted despite intensified immunosuppression including OKT3 antibody. MTX, given intravenously, orally, or by both routes at a dose of 10-175 mg (85 +/- 62 mg), reversed rejection in nine of 10 recipients (90%) within 7-63 days (26 +/- 18 days). Elevated pulmonary artery wedge pressures were reduced to normal levels after MTX therapy (15.2 +/- 3.5 before vs. 10.6 +/- 3.0 mm Hg after; p less than 0.05). Leukopenia occurred in five cardiac transplant recipients after treatment with MTX. Adverse reactions to MTX resolved after MTX therapy was discontinued in all but one recipient. This recipient received one of the larger MTX doses (150 mg) and developed fatal Pseudomonas pneumonia. Twelve moderate rejection episodes recurred in nine recipients, seven episodes of which were successfully re-treated with MTX. Two of these seven recipients have now been rejection-free for 15 months. Of five recurrent episodes of cardiac transplant rejection not treated with MTX, two could not be reversed and were fatal. MTX may be a valuable drug for reversing refractory cardiac allograft rejection. Before MTX therapy gains wider use, however, a clearer understanding of its enhanced ability to suppress the bone marrow is needed.

Adult↗