Association between tissue hypoxia and elevated non-protein sulphydryl concentrations in human cervical carcinoma xenografts.

A double staining technique was developed for the simultaneous measurement of tissue hypoxia and the concentration of non-protein sulphydryls (NPSH), based on the fluorinated nitroimidazole EF5 and the fluorescent histochemical NPSH stain 1-(4-chloromercuriphenoylazo)-naphthol-2 (mercury orange). Cryostat sections of tumour tissue were examined by fluorescence image analysis, using a computer-controlled microscope stage to generate large tiled field images of the cut tumour surface. This method was applied to the human cervical squamous cell carcinoma lines ME180 and SiHa, grown as xenografts in severe combined immunodeficient (SCID) mice, in order to determine if there is a systematic relationship between tissue hypoxia and NPSH levels. Hypoxic regions of the tumours, defined by EF5 labelling, were found to show greater NPSH concentrations relative to better oxygenated regions. This is probably due to increases in glutathione, since the ME180 and SiHa xenografts contained low levels of cysteine and metallothionein; the other major cellular thiols that can bind to mercury orange. Because the effects of glutathione on radiation and chemotherapy resistance are likely to be greater under hypoxic conditions, these results have potentially important implications for the study of resistance mechanisms in solid tumours.

Granuloma annulare: an elastic tissue disease? Case report and literature review.

Granuloma annulare (GA) is a condition characterized by the presence of palisading granulomas usually in the dermis. Traditionally, the histopathological changes are described as consisting of focal degeneration of dermal collagen fibers. However, no convincing evidence for such alteration is found in the literature. A histopathological study was done to ascertain the nature of the dermal abnormality. Ten skin biopsies showing lesions of GA were studied by light and electron microscopy. On light microscopy, all lesions showed focal dermal degeneration with near total loss of elastic fibers. Ultrastructural examination in nine cases demonstrated degenerated elastic fibers with loss of peripheral microfibrils and abnormal elastic matrix. The degenerated elastic fibers were surrounded by intact collagen fibers. These findings show that the main alteration in GA is elastic fiber degeneration and strongly suggest that the primary target leading to the development of this disorder is injury to the elastic tissue.

Diffuse leiomyomatosis of the esophagus: disorder of cell-matrix interaction?

Diffuse leiomyomatosis (DL) is rare condition characterized by proliferation of smooth muscle in the upper gastrointestinal tract. Most cases are associated with X-linked Alport syndrome and have partial deletions in the genes encoding both the alpha5 and alpha6 chains of collagen type IV. We studied aspects of cell-matrix interaction of myocytes in an esophagogastrectomy specimen from a 12-year-old patient with DL. Myocytes had central areas of cytoplasmic rarefaction, which were actin positive and desmin poor, with the reverse pattern of staining at the cell periphery. Electron microscopy (EM) showed that the areas of rarefaction consisted of disorganized aggregates of filaments. The basement membranes ranged from thickened to thinned or absent. Immunohistochemical staining for the alpha1-alpha4 chains of collagen type IV, the alpha1, alpha2, beta2, and gamma1 chains of laminin, nidogen, type VI collagen, and fibronectin was normal. There was loss of the alpha5 and alpha6 chains of collagen type IV and the beta1 chain of laminin. Normal staining for alpha1, alpha2, alpha3, alpha4, alpha6, alpha8, and beta1 integrins was noted. Staining for alpha5 integrin varied from normal to reduced or negative in different cells. In DL, a primary abnormality of basement membrane may be associated with disorganization of the contractile apparatus and alterations of certain integrins. This may reflect a disturbance of cell-matrix interactions that play a role in cell differentiation and internal organization.

The role of granulomatous phlebitis and thrombosis in the pathogenesis of cirrhosis and portal hypertension in sarcoidosis.

Sarcoidosis often involves the liver with mild elevation of serum enzymes and granulomas histologically. Rarely, chronic cholestasis, portal hypertension, cirrhosis, or nodular hyperplasia may be found. The pathogenesis of the portal hypertension and of the cirrhosis are not understood, in part because large samples of tissue have seldom been described. We describe the clinical and anatomic findings of four patients with sarcoid liver disease in whom the whole livers were available for examination. One patient had cirrhosis, one had diffuse nodular hyperplasia, and two had small regions of parenchymal fibrosis. The first two of these had a history of variceal bleeding and healed portal vein thrombosis. One had chronic cholestasis without cirrhosis. We suggest that the cirrhosis and focal fibrosis were caused by ischemia secondary to primary granulomatous phlebitis of portal and hepatic veins. The portal hypertension in two patients was likely secondary to portal vein thrombosis, because cirrhosis was absent at the onset of variceal bleeding.