J. F. Moura Nunes

Ultrastructural study of African swine fever virus replication in cultures of swine bone marrow cells.

SummaryCultures from pig bone marrow cells were infected with ASFV and the replication cycle was studied. In the cytoplasmic replication areas there are a differentiation of membrane segments. Some of them are polygonal, which give rise to virus particles. An over production of viral coded materials, including non-polygonal membranes seems to be an important feature of the replicative cycle of ASFV in this cell system. Viruses are released enveloped with a cellular membrane. Paracrystalline arrays of viruses are seldom seen in the cytoplasm. At no time did we see viruses in the nucleus. Infected cells showed marked cytopathic effect, beginning at early times post infection.

Expression of CD44 isoforms in normal salivary gland tissue: an immunohistochemical and ultrastructural study.

Abstract. We studied the expression of CD44 isoforms immunoreactivity in normal human salivary gland tissue, aiming at its full characterisation in normal epithelial and myoepithelial cell types. Optical immunohistochemistry techniques using monoclonal antibodies anti-CD44v3, CD44v4/5 and, for CD44v6, together with immunoelectron microscopy, were performed in serous, seromucinous and mucinous glands. Normal human breast and a case of lactating breast adenoma were used for comparative purposes and as controls. CD44v3 was positive in acinar and myoepithelial cells and was absent in mucin-producing cells from the different gland types. CD44v4/5 was consistently negative in all types of salivary tissue. CD44v6 was constantly positive in serous acinar cells, focally positive in basal cells of ducts, and myoepithelial cells consistently expressed it. At the ultrastructural level, CD44v6 was localised to the interdigitating processes of acinar cells, whenever they were not covered by basal lamina and to the cell membrane facing myoepithelial cells. In myoepithelial cells, immunolabelling was found at the membranes facing the acinar cells and in caveolae present at this interface. No labelling was found at cell membranes of both acinar and myoepithelial cells in contact with basal lamina or at the luminal aspect of the former. The finding of CD44v3 and v6 in myoepithelium of normal salivary glands may argue in favour of the role of these molecules in the regulation of growth and renewal of normal tissues and, potentially, on the morphogenesis of salivary gland neoplasms.

A kindred with multiple endocrine neoplasia type 2A associated with pruritic skin lesions.

Background. A kindred affected by multiple endocrine neoplasia type 2A (MEN 2A), associated with symmetric, bilateral, scapular pruritic skin lesions (PSL), is reported.

An experimental model for fatal malaria due to TNF-α-dependent hepatic damage

While BALB/c mice survive infection with blood stages of Plasmodium chabaudi chabaudi (AS), 70% of DBA/2 mice die by day 9-11 of infection, both strains controlling parasitaemia. We describe here that infection of DBA/2 mice results in extensive, multifocal hepatocyte death. Antibody neutralization of TNF-alpha prevents both liver damage and death.

Alveolar adenoma of the lung: further characterization of this uncommon tumour

Alveolar adenoma of the lung is a poorly characterized, uncommon pulmonary lesion with proliferation of alveolar epithelium and septal mesenchyme. We describe the electron microscopy, immunohistochemistry and DNA flow cytometry in a case of alveolar adenoma in a 55-year-old woman. Alveolar adenoma appears to be a distinct benign neoplasm of the alveolar structures. Our findings further suggest that it is not a precursor of bronchioloalveolar carcinoma or other type II pneumocyte lesions of presumed malignant potential.

Giant Mitochondria and Intramitochondrial Inclusions in Benign Thyroid Lesions

Enlarged mitochondria and intramitochondrial dense structures have been reported to occur in a great variety of animal and human cells under normal, pathologic, and experimental conditions. Three cases of benign thyroid lesions are described in which large cytoplasmic inclusions were seen on light microscopy. These inclusions were stained with toluidine blue but not with Sudan black B, as was seen in consecutive sections. Ultrastructural observation showed that they corresponded to giant mitochondria. Bundles of dense filaments and round, electron-dense bodies were observed in the matrix of the enlarged mitochondria. Incubation of ultrathin sections with proteolytic enzymes (pepsin, trypsin, and type XVI-protease) led to a striking decrease in the electron density of both types of intramitochondrial matrical structures. These observations demonstrate that a major proteic component exists in intramitochondrial filamentous bundles and in dense bodies.

Neuronal ceroid-lipofuscinosis: ultrastructural study of lymphocytic dense bodies.

We studied the ultrastructural alterations of the dense bodies of peripheral blood lymphocytes in one case of neuronal ceroid-lipofuscinosis. These cytoplasmic vesicles were characterized by vacuolar transformation and “fingerprint” content. When we tilted the specimens, the “fingerprint” arrangement was shown to be the same as the arrangement of the crystalloid inclusions found in the same cells. Both vacuoles and periodic cytoplasmic inclusions could be due to a disorder of secondary lysosomes—the lymphocytic dense bodies.

Micro-Buffy Coats of Whole Blood: A Method for the Electron Microscopic Study of Mononuclear Cells

A method for the electron microscopic study of human peripheral lymphocytes by which very small buffy coats are obtained through centrifugation of heparinized whole blood in glass or plastic microhematocrit tubes is presented. This method is time saving and efficient, yielding well preserved material and a comparatively large number of mononuclear cells (mainly lymphocytes) in each thin section.

Mitochondria-Rough Endoplasmic Reticulum Complexes in a Malignant Fibrous Histiocytoma

Mitochondria-rough endoplasmic reticulum complexes identical to the ones usually found in chordoma were frequently observed in tumors cells of a malignant fibrous histiocytoma arising in the left thigh of a 48-year-old woman. Although the significance of these structures is unknown, this finding is consistent with the known transformation of chordoma into malignant fibrous histiocytoma.

Photographic defocusing: a means to render recognizable line traced models of negatively stained biological specimens

A simple method of obtaining analogue images from traced models of biological specimens is presented. It consists of the photographic defocusing of traced models and it is illustrated with negatively stained cylindrical forms of the ASFV; the black lines of the trace in the model correspond to the negative stain surrounding the viral morphological subunits as seen in the electron micrograph. The photographic defocusing is the means by which the traced model is filtered and is used to introduce grey levels on an otherwise black and white image. The right amount of defocusing is attained when the width of the trace of the model equals the width of the rim of the negative stain appearing between the morphological subunits in the electron micrograph.