Morphological and immunohistochemical characteristics of dimethylnitrosamine-induced malignant mesenchymal renal tumor in F-344 rats.

Mesenchymal renal tumors in F-344 newborn rats were induced by a single dose of dimethylnitrosamine. The induced tumors were successfully transplanted into adult rats under the renal capsule. Neither the primary nor the transplanted neoplasms from various generations of grafts changed their morphological features during the tumor passage, having the same cellularity with high mitotic activity and the tendency to invade the host kidney rapidly. On the basis of lectin histochemistry and immunohistology, the tumor proved to be a mesenchymal neoplasm without any obvious capacity of the proliferating cells to differentiate into any well-known organoid element normally found in mature renal parenchyma. However, the proliferating neoplastic cells were found to have a strong vimentin positivity with desmin expression. Ultrastructurally, myofilaments with attachment bodies characteristic of smooth muscle cells were generally present in various amounts in many tumor cells. In addition, on the basis of the physiological data and on kidney/tumor renin activity obtained, it is interesting to note that the tumor-graft-invaded kidneys retained their enzyme activity, despite the obvious loss of renal tissue including glomeruli. However, the immunohistochemical findings with anti-renin antibody have clearly shown that this is not due to a renin-producing tumor but rather to the surviving (probably) non-neoplastic arterioles retaining the capacity to produce renin. Although these arterioles have mostly been found next to necrotic areas, commonly occurring in dimethylnitrosamine-induced transplantable renal tumors, the question of a possible physiological role of renin in tumor necrosis or in angiogenesis has remained open.

The expression of intermediate filaments in canine mammary glands and their tumors.

Monoclonal antibodies specific for different types of intermediate filaments (cytokeratin, vimentin, desmin and neurofilaments) were used to study the histogenesis of canine mammary glands and 57 canine mammary tumors by immunocytochemistry. The intra- and interlobular duct epithelium, acinar, and intralobular myoepithelial cells stained positively for cytokeratin. Peripheral ductal and acinar cells, as well as interstitial cells, stained positively for vimentin. A similar staining pattern was seen in adenomas, complex adenomas, benign mixed tumors, ductular carcinomas, and one myoepithelioma-like tumor. Additionally, cytokeratin positive cells were scattered interstitially in one single adenoma, most complex adenomas, some benign mixed tumors, complex carcinomas, and in the malignant mixed tumors. All stromal cells stained positively for vimentin. The fibrosarcomas were positive only for vimentin, while the following expressed both desmin and cytokeratin: epithelial-like cells in one adenoma, three complex adenomas, the myoepithelioma-like tumor, the single comedo carcinoma, two complex carcinomas, the single lobular carcinoma, one malignant mixed tumor, and three osteosarcomas. Epithelial-like cells in one adenoma, six complex adenomas, two benign mixed tumors, two complex carcinomas, the lobular carcinoma, and the malignant schwannoma stained for neurofilaments. Three tumors, one adenoma, one complex adenoma, and the lobular carcinoma expressed both desmin and neurofilaments in addition to cytokeratin and vimentin. The results show the expression of different types of intermediate filaments and indicate that there might be a stem cell origin in most of the canine mammary tumors.

Primitive cerebral neuroectodermal tumor with rhabdomyoblastic differentiation.

A case is presented of a primitive neuroectodermal tumor located in the left frontal cerebrum, which demonstrated electron microscopic and immunocytochemical evidence of rhabdomyoblastic differentiation. Within the group of supratentorial primitive neuroectodermal tumors, only medulloepithelioma has previously been shown to manifest "divergent" differentiation. In several respects our case is analogous to infratentorial "medullomyoblastoma."

Undifferentiated (embryonal) sarcoma of the liver with alpha-1-antitrypsin deposits: immunohistochemical and ultrastructural studies.

Periodic acid-Schiff-positive diastase-resistant globules are described in an undifferentiated (embryonal) sarcoma of the liver in a 14-year-old boy. These globules were shown to contain alpha-1-antitrypsin (A-1-AT) protein by immunofluorescence techniques. Further immunohistochemical studied revealed albumin and gamma globulins, but no alpha-feto protein (AFP). Electron microscopic studies showed large, electron-dense bodies consistent with phagolysosomal structures, and distinct from that described in alpha-1-antitrypsin deficiency (A-1-ATD). These findings suggested that the globules in this tumor may represent trapping of serum proteins by the malignant cell. These observations are discussed in connection with recent studies linking the deficiency disease and epithelial hepatic tumors.

Mesenquimoma do rim / Renal mesnchymoma

Os autores documentam um caso de mesenquimoma renal em paciente do sexo feminino, com 44 anos de idade. Discutem os achados na literatura e concluem que os tumores de Willms (nefroblastoma renal) em adultos, relatados na literatura, provavelmente representam tumores mistos mesodermais

Mesenchymal tumor hypoglycemia: the effect of a tumor tissue extract on the insulin and glucagon secretion from the isolated perfused porcine pancreas.

Severe fasting hypoglycemia and hypoinsulinemia occurred in a sixty-six year old woman with an intrahepatic mesenchymal tumor. An extract from the tumor was potent in inhibiting the arginine-induced glucagon secretion from the isolated perfused porcine pancreas. This observation supports the theory recently advanced that mesenchymal tumor hypoglycemia in some cases is due to a still unknown factor secreted from the tumor, which directly inhibits pancreatic glucagon secretion.

[DNA content in atypical gliomesenchymal elements in chemical blastomogenesis of the cerebellum in white rats]. / Soderzhanie DNK v atipichykh glio-mezenkhimal'nykh élementakh pri khimicheskom blastomogeneze mozzhechka belykh krys

A microphotometric comparative study was carried out; DNA content was determined in the atypical glio-mesenchymal elements around the villous capsule surrounding the DMBA pill, in the cells of microastrocytoma and microglioblastoma induced by DMBA. It was found that the late stages of this type of chemical blastomogenesis of the cerebellum of albino rats were characterized by the preservation of a distinct diploid modal class, excluding cases when the process coursed in the direction of malignization at the early stages of tumour progress (microglioblastoma).