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M Mégevand

Publications and source records attributed to M Mégevand.

6 recordsLinked to original sources

[Secondary polycythemias: the role of erythropoietin].

The discovery of high hemoglobin and hematocrit values in a patient necessitates the determination of the red blood cell mass in order to confirm the absolute character of the polycythemia. If a true polycythemia is confirmed, its etiology must then be established. The diagnostic approach of polycythemia is presented in this paper. It is illustrated by a case presentation in which a polycythemia secondary to a renal carcinoma is discussed. Erythrocytosis is a classical, albeit rare manifestation of this type of tumor, and has the advantage of allowing early detection. Thus, it permits a prompt treatment plan, thereby improving the prognosis of such a neoplasia. The usefulness of a serum level of erythropoietin (EPO) is subsequently discussed. The diagnostic value of EPO remains controversial because of the overlapping values recorded amongst healthy patients, patients with polycythemia vera and others with secondary polycythemia. Finally, we discuss the presence of substances in paraneoplastic polycythemias whose biological activity is close to that of EPO. However, this molecules of a different structure would not be detected by the radioimmunoassay used to measure erythropoietin level.

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Pregnancy-associated plasma protein-A concentrations in men with testicular and prostatic tumors.

Pregnancy-associated plasma protein-A (PAPP-A) is a macromolecular glycoprotein produced during pregnancy by the trophoblast and the decidua. It is not specific to pregnancy, since immunoreactive PAPP-A is in the circulation of normal women and men and in seminal fluid. Immunohistochemically, PAPP-A is localized in some Leydig cells, in the epididymis, in the rete testis, and in seminal vesicles. This study was conducted to learn whether circulating levels of PAPP-A can be used as a marker for the monitoring of human testicular cancer. PAPP-A was increased only in certain nonseminomatous germ cell tumor [malignant teratoma undifferentiated (MTU) + seminoma, malignant teratoma intermediate (MTI)], but the overlap with the normal values was too big for PAPP-A to have any clinical significance. After orchidectomy or prostatectomy, PAPP-A decreased but the levels were were similar to those of normal men. In men, PAPP-A can be produced by certain nonseminomatous germ cell tumors, but its origin in disease-free males is probably not the testis or the prostate.

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