Histology and histopathology Vol.12, nº 2 (1997)
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- PublicationOpen AccessCollagen types Vlll and X, two non-fibrillar, short-chain collagens. Structure homologies, functions and involvement in pathology(Murcia : F. Hernández, 1997) Sutmulle, M.; Bruijn, J.A.; De Heer, E.. Collagens can be divided into two groups, Le., fibrillar and non-fibrillar collagens. Short-chain collagens, a subgroup of non-fibrillar collagens, comprises collagen type VI11 and type X. These two collagen types show severa1 similarities in stnicture and possibly also in function. Type VI11 collagen appears to be secreted by rapidly proliferating cells. It can be found in basement membranes and may serve as a molecular bridge between different types of matrix molecules. In different tissues this collagen type may serve different functions. Stabilization of membranes, angiogenesis, and interactions with other extracellular matrix molecules. Since collagen type X is produced by hypertrophic chondrocytes, this collagen type can only be found in matrix of the hypertrophic zone of the epiphyseal growth plate cartilage. Collagen type X is probably involved in the process of mineralization, endochondral ossification, and is also proposed to play a role in angiogenesis. Collagen types VI1 and X may be involved in matrix and bone disorders. Their structure, function, and involvement in pathology are discussed in this review.
- PublicationOpen AccessDistribution and pathophysiologic role of molybdenum-containing enzymes(Murcia : F. Hernández, 1997) Morikawa, Y.; Yamamoto, T.; Higashino, K.The importance of molybdenum-containing enzymes in the pathophysiology of a number of clinical disorders necessitates a comprehensive understanding of their histological localization and expression. The objectives of this review are to cover such enzymes so far reported and their enzyme- and immunohistochemical localization in various tissues and species, and to discuss their possible pathophysiological effects. The molybdenum cofactor is essential for the activity of the three molybdenum-containing enzymes, sulfite oxidase, xanthine oxidase and aldehyde oxidase. Sulfite oxidase serves as the terminal enzyme in the pathway of the oxidative degradation of sulfur amino acids, and is also involved in preventing the toxic effects of sulfur dioxide. Biochemical study has revealed a high activity of sulfite oxidase mainly in the liver, heart and kidney with lesser activity observed in other tissues. Subcellular observations have shown that this enzyme is present in the mitochondrial intermembraneous spaces. Xanthine oxidase is the final enzyme in the conversion of hypoxanthine to xanthine, and subsequently, to uric acid. Unlike sulfite and aldehyde oxidases, xanthine oxidase can be converted to xanthine dehydrogenase, and vice versa. Xanthine oxidase has been widely investigated for its role in post-ischemic reperfusion tissue injury. Enzyme- and immunohistochernical studies of its localization in various animal species and tissues have shown its ubiquitous distribution in the liver, small and large intestine, lung and kidney, and other tissues. Aldehyde oxidase shares a similar substrate specificity with xanthine oxidase. Although the tissue localization of this enzyme has not been studied as thoroughly as that of xanthine oxidase, aldehyde oxidase is reportedly found in the digestive gland of terrestrial gastropods, the antennae of certain moths as well as the mammalian liver. Recently, the ubiquitous distribution of aldehyde oxidase has been demonstrated in rat tissues. The aldehyde oxidase activity of herbivores exceeds that of carnivores, suggesting a possible role of this enzyme as a Offprint requests to: Dr. Yuji Moriwaki, M.D., Third Department of lnternal Medicine, Hyogo College of Medicine, Mukogawa-cho 1-1, Nishinomiya, Hyogo 663, Japan protection against the effects of toxic plants. The relationship between the tissue localization of these enzymes and their pathophysiological roles is reviewed.
- PublicationOpen AccessEndotheliitis-like changes in chronic hepatitis C(Murcia : F. Hernández, 1997) Lory, J.; Zimmermann, AstridLiver biopsies in hepatitis C frequently show bile duct damage, lymphoid follicles, large and small droplet fat, hepatocyte multinucleation. Mallory bodylike material, and activation of sinusoidal inflammatory cells. Even though these lesions are useful parameters in the diagnosis of hepatitis C, their specificity remains uncertain. Endotheliitis-like changes of small portal veins have been described for various liver diseases, including viral hepatitis. The aim of the present study was to investigate the prevalence and severity of endotheliitis-like changes in chronic hepatitis C in comparison with chronic hepatitis B. For this purpose, liver biopsies of 50 patients with chronic hepatitis C and 48 patients which chronic hepatitis B were systematically analyzed for the presence of endotheliitis-like changes. Endotheliitis-like changes were defined as lymphocytic infiltration of venous walls, subendothelial lymphocyte accumulation, adherence of lymphocytes to the endothelium, and endothelial cell damage. Endotheliitis-like change severity was graded (borderline/questionable; slight to moderate; severe), and endotheliitis-like changes were analyzed in small portal veins and in central veins. Endotheliitis-like changes were significantly more frequent in chronic hepatitis C than in chronic hepatitis B (41.5% vs. 6.9%; ~ 0 . 0 5 ) . In chronic hepatitis C, endotheliitis-like changes predominated in small portal veins, but 27% of small hepatic veins were involved as well. The findings indicate that endotheliitis-like changes may represent a useful histological parameter in the diagnosis of chronic hepatitis C.
- PublicationOpen AccessComparative stereological studies on zonation and cellular composition of adrenal glands of normal and anencephalic human fetuses. II. Cellular composition of the gland(Murcia : F. Hernández, 1997) Bocian-Sobkowska, J.; Malendowicz, L.K.; Woíniak, W.In our previous paper (Bocian-Sobkowska et al., 1997) we demonstrated a striking difference in development of zonation in adrenals of normal and anencephalic human fetuses. The purpose of the present study was to characterize, by means of stereology, the cellular composition of developing adrenals in the same case. Studies were performed on 11 pairs of adrenal glands from normal fetuses and 10 from anencephalic fetuses. In the studied period of development (24 to 39 weeks of intra-uterine life) the average volume of cells in normal glands increased as follows: zona glomerulosa (ZG) from 355 to 870 pm3; zona fasciculata (ZF) from 779 to 1200 pm3; fetal zone (FZ) from 2004 to 2380 pm3; and medulla (M) from 600 to 970 ym3. In anencephalic fetuses, the appropriate values were: ZG - 380-680 pn3; ZF - 460-680 pm3; FZ - 1820-1680 pm3; and M - 870-1400 pm3. At the end of the studied period the number of ZG cells in normal fetuses was two fold higher than in anencephalics, ZF cells - 6-fold and in FZ - 5-fold higher, while in the M the number of cells was nearly equal in both groups. During the whole investigated period of intra-uterine development the total number of adrenocortical cells in normal glands increased ca 2.5-fold, while in anencephalic glands only ca 0.5-fold, reaching at the end ca 40% of normal value. In both normal and anencephalic adrenals the number of ZG and M cells was highly correlated with ZG/M cell ratio, being slightly higher in normal glands. No such relation was demonstrated for cells of the remaining adrenocortical zones.
- PublicationOpen AccessMembrane skeletons in avian erythrocytes as revealed by the quick-freezing and deep-etching method(Murcia : F. Hernández, 1997) Terada, N.; Fuji, Y.; Kitano, K.; Ohno, S.Ultrastructure of chicken erythrocytes were examined by the quick-freezing and deep-etching (QFDE) method. Some erythrocytes were fixed with paraformaldehyde and prepared with erythrocytesplitting method or saponin treatment to remove soluble proteins before quick-freezing. Others were prepared in the cytosol buffer with the erythrocyte-splitting method to obtain natural state of cytoskeletons. Non-expanding membrane skeletons were highly condensed on the cytoplasmic side of lipid membrane in the paraformaldehyde- fixed specimens. Under unilateral extension of the specimens, long stretched filaments were connected alternately with condensed filamentous or granular structures under erythrocyte membranes. As the membrane skeletons got closer to the marginal bands, they become more dense network structures. Moreover, in the fresh unfixed specimens, dense networks of filaments were localized underlying erythrocyte membranes in a relatively intact state. Fine filaments connected the marginal microtubule bands to the cytoplasmic sides of erythrocyte membranes. The different distribution of each cytoskeletal component and the association of these structures may support the elliptocytic shape of chicken erythrocytes and resist the dynamic circumstance.