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Biomedical subjects

R Melamed

Publications and source records attributed to R Melamed.

28 records · Page 2Linked to original sources
PubMed1982

Intraoperative nerve fascicle identification using choline acetyltransferase: a preliminary report.

One reason for failure of nerve recovery after suture or nerve grafting is the inappropriate matching of motor and sensory fibers. Methods used in attempting to solve this problem have either been unprecise, too time consuming, or unpleasant to the patient. Both experimentally and on cadaver samples, the level of choline acetylase activity is eight times higher in motor nerve fascicles than in sensory fascicles. In experimentally cut nerves, the ChAC activity remained high even after a period of 45 days. Thus it was possible to identify both ends of the motor and sensory fascicles in fresh injuries, and the proximal parts in old injuries. We have since used this method of intraoperative nerve identification in three patients. It has proved to be a rapid (70-80 minutes), viable technique for the immediate differentiation between proximal parts of motor and sensory nerve fascicles in cases of old nerve injuries. In contrast to our animal studies we found that the ChAC activity in the distal segment was still different for the various fascicles five months after transection. Presumably the present need for distal exploration to identify the "target organ" can be avoided.

Adult↗
PubMed1981

Choline acetyltransferase nerve identification method in early and late nerve repair.

Choline acetyltransferase (ChAC) measurement after complete transection of the sciatic nerve in rats revealed a steady increase in ChAC in the proximal nerve stump and a rapid drop in ChAC in the distal nerve stump. Ninety-six hours following transection no appreciable ChAC activity could be detected in the distal segment. The increase in the proximal segments was followed by a slight decline and leveling off at about twice the normal level. End-to-end nerve anastomosis, using the enzymatic nerve differentiation technique, could therefore be performed up to the first 96 hours. Nerve grafts could be used, with markedly improved results, up to the forty-fifth day following transection.

Animals↗
PubMed1980

Choline acetyltransferase for differentiation between human motor and sensory nerve fibers.

A rapid and precise nerve fascicle identification method based on the enzymatic activity of choline acetyltransferase (choline acetylase, or ChAC) is described. Motor nerve facicles demonstrated significantly higher ChAC activity in comparison to sensory nerve facicles. Based on this difference in activity, matching of nerve fascicle cut ends is possible in cases of recent trauma.

Afferent Pathways↗
PubMed1980

Segmental transit time in coronary arteries with varying degrees of stenosis.

The transit time of contrast material through a proximal segment of right coronary and anterior descending arteries were measured from cineangiograms by means of a projector-linked frame counter. The time required for the contrast material to traverse a 15-cm segment from the ostia was more than 800 msec in 58 out of 80 vessels with more than 85% stenosis and only in 12 of 129 vessels with up to 85% stenosis. This simple measurement during routine interpretation of cineangiograms may add valuable information.

Cineangiography↗
PubMed1978

False aneurysm of the left ventricle. Surgical treatment.

The clinical and pathological features in three cases of false aneurysm of the left ventricle are reported. In two instances the condition developed after myocardial infarction, and in the third case a mycotic pseudoaneurysm developed after purulent pericarditis. All three patients were in intractable heart failure before urgent operation. The correct diagnosis was established preoperatively by angiography. In all three cases the aneurysms were successfully resected and the left ventricle reconstructed. An aggressive surgical approach is warranted in the management of this lesion.

Aged↗
PubMed1977

Mural endocarditis associated with recurrent false aneurysm of the left ventricle.

Acute bacterial endocarditis developed in a 65-year-old man two years after surgical resection of a false aneurysm of the left ventricle. The patient had cerebral embolic manifestations, and coagulase-positive Staphylococcus aureus was cultured from each of six blood samples. A pericardial friction rub and a changing pansystolic murmur appeared during the third week of hospitalization. The presence of a false aneurysm was once again demonstrated on ventriculographic studies. This was successfully repaired, employing cardiopulmonary bypass. The sequence of events in this patient suggests that bacterial endocarditis at the site of a previous cardiomyotomy might have led to the development of the second pseudo-aneurysm.

Aged↗
PubMed1976

Osteogenesis imperfecta with mitral insufficiency due to ballooning of the mitral valve. A case report.

A further case of osteogenesis imperfecta with valvular heart disease is added to the 12 already reported in the literature. The presence of a dilated mitral annulus and a ballooned mitral leaflet in this case together with the findings reported in the literature leave little doubt as to the relationship between the valvular lesion and the underlying connective tissue disorder.

Dilatation, Pathologic↗