Biomedical subjects

R Mentzer

Publications and source records attributed to R Mentzer.

4 recordsLinked to original sources

PubMed1997

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↗

PubMed1988

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↗

PubMed1980

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↗

PubMedDate not supplied

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.

Aged↗