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J Merchan

Publications and source records attributed to J Merchan.

7 recordsLinked to original sources
PubMed1983

Plexiform structures in malignant schwannomas after prenatal exposure to ethylnitrosourea.

75 Schwann cell tumors were induced in the offspring of Wistar rats which had been treated intraperitoneally with 15 mg/kg b.w. ethylnitrosourea on the 15th day of pregnancy. Plexiform structures characterized by poorly-developed, distorted and bizarre bundles of nerves were seen in 2 of 33 benign tumors, and in 17 of 42 malignant schwannomas. Since when seen in man similar findings are distinctive of neurofibromatosis, it is suggested that this experiment may offer a model for studying non-inherited forms of neurofibromatosis and, more particularly, the malignant changes often associated with this disease.

Animals↗
PubMedDate not supplied

[Electronmicroscopical aspects of endometrial distrophy induced by oral contraceptives (author's transl)].

An electron-optical study on the endometrium of 5 controls and 25 patients subjected during 3-12 months to 0.25 mg norgestrel + 0.05 mg etinil-estradiol association treatment is performed. The most prominent electronmicroscopical features of endometrial changes are described, such as the asynchronical maturation of the epithelium and the stroma, the shorthening of the proliferative and secretory phases and the epithelial involution towards the last days of the cycle. Special emphasis is placed on the zonal distribution of these changes. An increase of the nostocitosis phenomena is reported and its significance as a complementary contraceptive mechanism is discussed.

Endometrium↗
PubMedDate not supplied

[Morphological contributions to the knowledge of testicular pathology (author's transl)].

Among a serie of more than 500 biopsies, the authors show some testicular lesions of difficult interpretation which do not seem to have been reported previously. The electron-microscopical findings are: Contrarily to the uniform thickening of the seminal tube's anhista basal hyalino -esclerosis, in the Klinefelter's syndrome, the anhista shows focal bizarre thickenings, which have been repeteadly observed in the 15 cases studied. Well defined collagen inside the Leydigs's cytoplasm the authors discuss the possible importance of this unique finding in a 28 years old azoospermyc as revealing cellular inmaturity (fibroblastic origin of the interstitial cells). In light microscopy, they discuss the role of the "Hiatus Germinalis", typical of the oligospermies, as related to alterations of the maturation process.

Biopsy↗