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Biomedical subjects

R Mentzer

Publications and source records attributed to R Mentzer.

5 recordsLinked to original sources

A randomized active-controlled trial of mycophenolate mofetil in heart transplant recipients. Mycophenolate Mofetil Investigators.

BACKGROUND: After heart transplantation, 1-year and 5-year survival rates are 79% and 63%, respectively, with rejection, infection, and allograft coronary artery disease accounting for the majority of deaths. Mycophenolate mofetil (MMF), an inhibitor of the de novo pathway for purine biosynthesis, decreases rejection in animals and in human renal transplantation. METHODS: In a double-blind, active-controlled trial, 28 centers randomized 650 patients undergoing their first heart transplant to receive MMF (3000 mg/day) or azathioprine (1.5-3 mg/kg/day), in addition to cyclosporine and corticosteroids. Rejection and survival data were obtained for 6 and 12 months, respectively. Because 11% of the patients withdrew before receiving study drug, data were analyzed on all randomized patients (enrolled patients) and on patients who received study medications (treated patients). RESULTS: Survival and rejection were similar in enrolled patients (MMF, n=327; azathioprine, n=323). In treated patients (MMF, n=289; azathioprine, n=289), the MMF group compared with the azathioprine group was associated with significant reduction in mortality at 1 year (18 [6.2%] versus 33 deaths [11.4%]; P=0.031) and a significant reduction in the requirement for rejection treatment (65.7% versus 73.7%; P=0.026). There was a trend for fewer MMF patients to have > or = grade 3A rejection (45.0% versus 52.9%; P=0.055) or require the murine monoclonal anti-CD3 antibody or antithymocyte globulin (15.2% versus 21.1%; P=0.061). Opportunistic infections, mostly herpes simplex, were more common in the MMF group (53.3% versus 43.6%; P=0.025). CONCLUSIONS: Substitution of MMF for azathioprine may reduce mortality and rejection in the first year after cardiac transplantation.

Aged↗

Ryanodine receptor dysfunction in porcine stunned myocardium.

We investigated the effects of myocardial stunning on the function of the two main Ca2+ transport proteins of the sarcoplasmic reticulum (SR), the Ca(2+)-adenosinetriphosphatase and the Ca(2+)-release channel or ryanodine receptor. Regional myocardial stunning was induced in open-chest pigs (n = 6) by a 10-min occlusion of the left anterior descending coronary artery (LAD) and 2 h reperfusion. SR vesicles isolated from the LAD-perfused region (stunned) and the normal left circumflex coronary artery (LC)-perfused region were used to assess the oxalate-supported 45Ca2+ uptake, [3H]ryanodine binding, and single-channel recordings of ryanodine-sensitive Ca(2+)-release channels in planar lipid bilayers. Myocardial stunning decreased LAD systolic wall thickening to 20% of preischemic values. The rate of SR 45Ca2+ uptake in the stunned LAD bed was reduced by 37% compared with that of the normal LC bed (P < 0.05). Stunning was also associated with a 38% reduction in the maximal density of high-affinity [3H]ryanodine binding sites (P < 0.05 vs. normal LC) but had no effect on the dissociation constant. The open probability of ryanodine-sensitive Ca(2+)-release channels determined by single channel recordings in planar lipid bilayers was 26 +/- 2% for control SR (n = 33 channels from 3 animals) and 14 +/- 2% for stunned SR (n = 21 channels; P < 0.05). This depressed activity of SR function observed in postischemic myocardium could be one of the mechanisms underlying myocardial stunning.

Animals↗

Experimental prosthetic vein valve.

The incidence of venous insufficiency is increasing, approximately 800,000 new cases are reported yearly in the United States. Medical treatment of venous insufficiency syndrome has been associated with a high incidence of failure. Although vein valve transplantation has resulted in improvement in the majority of cases, late degeneration and incompetency of the valve prompted us to devise a prosthetic vein valve for experimental use. Ten dogs underwent insertion of a prosthetic vein valve without anticoagulants. Between 3 and 8 months after insertion, ascending and descending venography revealed patency and competency of these valves.

Animals↗

Acute suppurative thyroiditis.

Acute suppurative thyroiditis is a rare disease which may be confused with other, more common thyroid disorders. Gram-positive organisms such as Streptococcus, Staphylococcus, and Pneumococcus are most frequently responsible for this condition. Appropriate antibiotics should be selected to control local and systemic signs of infection. Incision and drainage of fluctuant areas are indicated. Thyroid function almost always returns to normal with eradication of infection.

Acute Disease↗

Mycotic carotid artery aneurysm.

A painful, pulsatile neck mass with associated fever should suggest the presence of a mycotic carotid artery aneurysm. Diagnosis can be confirmed from angiograms. Broad spectrum antibiotics are indicated, and an operation should be performed promptly. The lack of tissue planes uninvolved by infection will almost always prevent vascular reconstruction. Carotid artery ligation with excision of the aneurysms is recommended.

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