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Biomedical subjects

L C Martin

Publications and source records attributed to L C Martin.

43 records · Page 3Linked to original sources

New substrates for the radioassay of angiotensin converting enzyme of endothelial cells in culture.

To develop means of measuring angiotensin converting enzyme of endothelial cells in culture, we have synthesized benzoyl-Phe-Ala-Pro-OH (I), benzoyl-Pro-Phe-Arg-OH (II) and benzoyl-Gly-His-Leu-OH (III), each bearing a 3H-atom on the para-position of its benzoyl moiety. All three of the acylated tripeptides are substrates for the enzyme. Substrate I exhibits the lowest Km (12.5 micrometer) and yields the most sensitive assay: the enzyme of 10(6) cells can be measured in a 30 min incubation at 37 degrees C. Radiolabelled reaction product is separated from substrate by extraction of acidified reaction mixture with an organic solvent, and the rate of formation of product can be quantified by liquid scintillation counting of the organic phase. Substrate III can also be used to measure angiotensin converting enzyme of cells but requires longer incubations (180--240 min) and high salt concentrations (0.75 M Na2SO4). Substrate II is not specific: it is hydrolyzed by more than one enzyme of endothelial cells.

Cells, Cultured↗

Subhepatic collections complicating laparoscopic cholecystectomy: percutaneous management.

Ten patients with subhepatic fluid collections complicating laparoscopic cholecystectomy were successfully treated by interventional radiological procedures. The series included five abscesses, three hematomas, one biloma, and one serous collection. Abdominal pain or fever developed from 3 to 21 days after the laparoscopic intervention. All patients were asymptomatic 72 h after percutaneous drainage and there were no complications related to the procedure. Subhepatic fluid accumulations are common findings after laparoscopic cholecystectomies and have been considered an unreliable indicator of infection or other postoperative complications. However, the significance of these collections should not be underestimated in symptomatic patients. In such cases we propose diagnostic aspiration and drainage, when necessary, to safely and promptly establish the precise diagnosis and treatment. More serious complications can be avoided by early percutaneous intervention.

Adult↗

The silent period in patients with chronic renal failure undergoing hemodialysis.

Silent period was evaluated in 20 adult male patients with chronic renal failure undergoing hemodialysis. Readings were obtained by supramaximal stimulus to the median nerve, during maximum isometric effort of the abductor pollicis brevis muscle against resistance. Two types of abnormalities were observed, motor neuron hypoexcitability with elongated silent period, and motor neuron hyperexcitability with reduction or absence of silent period. Some abnormalities are probably linked with dialysis duration, but show no correlation to presence or absence of peripheral neuropathy. The silent period alterations described in this study could possibly correlate with some other clinical feature frequently seen in patients with chronic renal failure such as hypereflexia of the deep tendon reflexes.

Adult↗

[Clinical characteristics and prognostic implications of renal involvement in multiple myeloma].

The renal involvement in patients with multiple myeloma has been described as a sign of poor prognosis. The influence of renal insufficiency in the clinical patterns and in the prognosis of patients with multiple myeloma was studied retrospectively in 45 patients. Patients with renal insufficiency, at first visit, more often presented weight loss, proteinuria, hypercalcemia. The means of uricemia, ESR, were higher and the hematocritic mean was lower in patients with renal insufficiency. There was no difference in edema, arterial hypertension, fractures and bone pain. The reversibility of renal insufficiency occurred in 47% of the cases, which happened more often in the first months of the follow up. The creatinine mean was lower in patients with reversible renal insufficiency. The median survival was: patients with renal insufficiency: 11 months; patients with normal renal function: 50 months. Among patients with renal insufficiency those with recuperation of renal function showed a higher median survival (24 months) than those with irreversible renal insufficiency (1 month). The renal involvement then is frequent and often reversible. Patients with impaired renal function showed a worse prognosis; normalization of the renal function was associated with a better outcome.

Acute Kidney Injury↗