Tariq M. Murad

Role of the pericyte in wound healing: An ultrastructural study☆

Abstract Mesenchymal cells present in early wounds were divided into two groups: primitive mesenchymal cells and macrophages. Primitive mesenchymal cells appeared to become incorporated in the thick basement membrane of recently formed capillaries, and they also appeared to differentiate into fibroblasts. After becoming encased in vascular basement membrane these cells, pericytes, featured areas of cytoplasmic contact with underlying endothelium. It is proposed that the pericyte-endothelial “contacts” act as a regulatory mechanism for capillary proliferation.

Ultrastructure of a hemangiopericytoma and a glomus tumor

A comparative ultrastructural study of a case of hemangiopericytoma and one of glomus tumor is presented. The study revealed the hemangiopericytoma cells to be large with large irregular nuclei. The intercellular spaces are filled with light osmiophilic material resembling basement membrane. In the glomus tumor, two types of cells are identified. The more frequent cells are epithelioid smooth muscle cells with large ovoid nuclei and cytoplasm filled with fine filaments. The second type of cell is less frequent and is recognized as a mast cell. It is suggested that the release of mast cell granules plays an important role in the contraction of epithelioid smooth muscle and therefore controls the flow of blood in the glomus structure.

Ultrastructure of fibrosarcoma in a male breast

A case of fibrosarcoma in a male breast was studied with light and electron microscope. The study revealed a close morphologic similarity between the neoplastic cells and the fibroblasts. The neoplastic cells differ from normal fibroblasts in having increased number of cytoplasmic filaments and multiple nucleoli. These features were thought to be the result of neoplastic transformation. It is also thought that this neoplasm arose from the pectoral fascia.

Ultrastructure of myoepithelial cells in human mammary gland tumors.

The relationship of myoepithelial cells to epithelial cells in normal mammary gland and in various diseases of this organ were studied. The evidence suggests that myoepithelial cells play an important role in the formation of some benign and malignant tumors of the breast. The study also showed the presence of light and dark myoepithelial cells.

Ultrastructure of mycosis fungoides.

Six biopsies from 5 cases of treated and untreated mycosis fungoides were studied with the light and electron microscope. The study revealed the presence of a characteristic cell type in the skin lesions. The characteristic cells had large infolded nuclei, scant cytoplasm, and few organelles. Mitochondria were clustered in one region of the cytoplasm in which the Golgi apparatus was found. Treatment with systemic corticosteroids and electron beam therapy caused no significant change in the mycosis fungoides cells. Treatment with chemotherapy appeared to damage the malignant cells to a lesser extent than the surrounding cells. The combination of chemotherapy and x‐irradiation caused smoothening of the nuclear envelope, vesiculation of the endoplasmic reticulum, mitochondrial swelling, and the appearance of membrane‐bound lysosome‐like bodies. These changes were seen in both the mycosis fungoides cells and in other cell types present in the cutaneous lesions. No method of treatment produced necrosis in the mycosis fungoides cells.

Ultrastructure of a chordoma.

A case of chordoma was studied with light and electron microscopes. The study revealed the presence of 2 cell types—the stellate and the physaliferous cells—and many transitional cells were observed sharing some features of both cell types. Mitoses were found only in the stellate cell type. Virus‐like particles were frequently seen in the cytoplasm of the intermediate and physaliferous cells. Various nuclear morphology was observed and thought to be related to cell differentiation or to the formation of virus‐like particles. The study confirmed previous reports on the presence of 2 cell types and indicated that the physaliferous cells evolved from the stellate cells through a process of cisternal dilatation and secretion.

A proposed histochemical and electron microscopic classification of human breast cancer according to cell of origin.

Thirty‐six cases of breast carcinoma were classified according to their cells of origin using electron microscopy and ultrastructural histochemistry. The study showed that breast cancer can be classified into myoepithelial, ductal epithelial, and ductular epithelial carcinoma. In this study, all cases were easily classifiable except one mixed myoepithelial and ductular type which was classified as ductular carcinoma. Alkaline phosphatase, which is normally present in the myoepithelial cells of normal duct, becomes negative upon neoplastic transformation. Myoepithelial cancer cells retain their adinosine triphosphatase activity, and this behavior was helpful in identifying their cell of origin. Ductular epithelial cancer shows nuclear and free cytoplasmic acid phosphatase, and the significance of this finding was discussed. The study also revealed that carcinoma of ductular origin has a higher eventuality of metastases. Also, it was suggested that ductular carcinoma arises from hormonally sensitive cells, and the possibility of hormonal treatment for this cancer should be studied.

The ultrastructure of fibrocystic disease of the breast.

Twenty‐two cases of fibrocystic disease were studied with light and electron microscopes. Histologically, the manifestations of fibrocystic disease are divided into five groups presenting a consistent light‐ and electron‐microscopic appearance that includes: blunt duct adenosis, epithelial cell hyperplasia, sclerosing adenosis, “myoepithelial cell proliferation,” cyst with atrophic epithelium and cyst with apocrine changes. Fibrous stroma, lymphocytic infiltration and other features found with fibrocystic disease are not described here because of their presence in conditions other than fibrocystic disease. On the basis of the present study it is concluded that fibrocystic disease involves both epithelial and myoepithelial cells of the mammary duct.

Ultrastructure of a virilizing ovarian Sertoli‐Leydig cell

A case of virilizing ovarian Sertoli‐Leydig cell tumor in a young female was studied by light and electron microscopy. The ultrastructural findings were similar to those reported in the literature and suggest the presence of two types of cells which have a common origin. The patients aunt and grandmother had had similar tumors; the one in the aunt proved malignant. The English literature review revealed the familial occurrence of virilizing ovarian tumor in only two previous cases. Virus‐like particles were seen in our case and the significance of this observation was discussed.

Latent effect of DMBA on adrenal glands of Sprague-Dawley rats: An ultrastructural study☆

Abstract The latent effect of DMBA on the adrenal glands of Sprague-Dawley rats was studied by light and electron microscopy. DMBA or its metabolites seem to have a direct effect on the cells of the zona fasciculata and zona reticularis of the adrenal glands, causing severe mitochondrial structural alterations including variation in size. Calcification was observed in the majority of the cases and was believed to be a consequence of adrenal hemorrhage and cellular injury and not the result of a direct effect of DMBA on the adrenal cortical cells.