Histology and histopathology Vol.23, nº7 (2008)

Ir a Estadísticas

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    Lectin histochemistry for in situ profiling of rat colon sialoglycoconjugates
    (Murcia : F. Hernández, 2008) Accili, Daniela; Menghi, Giovanna; Gabrielli, M.G.
    The growing interest in glycoconjugates expressed and released by the epithelium of the intestinal mucosa is tightly related to the multiple functional roles attributed to sialic acid and its derivatives. In the present work, biotin and HRP conjugated lectins were used to detect the sialylation pattern and to identify specific structural features of sialoderivatives in the rat colon. In particular, the occurrence and distribution of sialic acids linked a2,6 to D-Gal/D-GalNAc and a2,3 to D-Gal were directly demonstrated with SNA and MAL II binding, respectively. In addition, in order to by-pass the specificity problems of SNA and MAL II as histochemical reagents, as well as to look for additional and complementary information about acetylation degree and sites, we combined sialidase digestion, potassium hydroxide deacetylation, and differential periodate oxidation with PNA and DBA binding. The data showed the distribution and structure of sialic acidß- D-Gal(1-3)-D-GalNAc and sialic acid-D-GalNac sequences, which proved to be widely distributed as cellular components or secretory products in surface goblet cells and crypt cells of the colonic epithelium. A high degree of O-acetylation, with acetyl groups mainly at 9 and 4 positions, was found, showing an increasing gradient from the proximal to distal portion of the colon. These results, which largely reproduce the sialylation pattern in other species, contribute new insights in defining the tissue specific expression of sialoderivatives in the colonic mucosa, and testify to their high heterogeneity which the wide range of sialic acid functional correlates in the intestinal tract depend on.
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    Expression of inwardly rectifying K+ channels in the carotid body of rat
    (Murcia : F. Hernández, 2008) Yamamoto, Y.; Ishikawa, R.; Omoe, K.; Taniguchi, K.
    The inwardly rectifying K+ channels, Kir1.1, Kir2.3, Kir4.1-Kir5.1, and Kir4.2-Kir5.1, are candidate chemosensory molecules for CO2/H+. Here, we determined the mRNA expression and immunohistochemical localization of these channels in the carotid body (CB) and petrosal ganglion (PG) of the rat. RT-PCR analysis revealed mRNA expression of Kir4.1 and Kir5.1 in CB, and Kir1.1, Kir4.1, and Kir5.1 in PG. Immunohistochemistry identified the glomus cells in CB to express both Kir4.1 and Kir5.1 protein, while the nerve fibers in CB were immunoreactive for Kir1.1, Kir4.1, and Kir5.1. In the PG, immunoreactivity for Kir1.1, Kir4.1, and Kir5.1 was observed in some ganglion cells. Our findings suggest that Kir channels in the peripheral chemoreceptors play a role in sensing hypercapnic acidosis and maintaining the resting membrane potentials.
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    Expression of the Shwachman- Bodian-Diamond syndrome -SBDS- protein in human pancreatic cancer and chronic pancreatitis
    (Murcia : F. Hernández, 2008) Kayed, Hany; Bekasi, Sandor; Keleg, Sehereen; Welsch, Thilo; Esposito, Irene; Shimamura, Akiko; Michalski, Christoph W.; Friess, Helmut; Kleeff, Jörg
    Background: The Shwachman-Bodian- Diamond syndrome (SBDS) protein is a member of a highly conserved family which influences RNA activation and is associated with pancreatic, skeletal and bone marrow deficiencies, as well as hematological malignancies. Methods: In this study, the expression and localization of SBDS were investigated in normal human pancreatic tissues, chronic pancreatitis (CP) tissues, primary and metastatic pancreatic ductal adenocarcinoma (PDAC) tissues, as well as in cultured pancreatic cancer cell lines by immunohistochemistry, immunoblotting and immunocytochemistry. Results: In the normal pancreas, SBDS was localized in the cytoplasm of islet cells and ductal cells. In CP tissues, SBDS was found in the cytoplasm of ductal cells, tubular complexes, stromal fibroblasts and in PanIN1-2 lesions. In PDAC tissues, SBDS exhibited cytoplasmic and occasionally nuclear localization in tubular complexes, PanIN1-3 lesions, cancer cells, and stromal fibroblasts. Different levels of SBDS protein were detected in cultured pancreatic cancer cell lines. Conclusion: SBDS is expressed in normal, CP, and PDAC tissues, as well as in pancreatic cancer cell lines. The different expression and localization patterns suggest a role of SBDS in the pathogenesis of, or response to, inflammatory and neoplastic pancreatic diseases.
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    Cardiac ischemia and reperfusion in spontaneously diabetic rats with and without application of EGb 761, I. cardiomyocytes
    (Murcia : F. Hernández, 2008) Schneider, Rick; Welt, Klaus; Aust, Wolfram; Löster, Heinz; Fitzl, Günther
    Diabetic cardiomyopathy is known to result in increased mortality after ischemic events. Permanently increased oxidative stress with formation of oxygen-free radicals plays a key role in the development of specific heart muscle disease. Associated lesions include structural alterations to cardiomyocytes. Antioxidative treatment in addition to the usual insulin substitution would seem sensible in preventing or delaying long-term diabetic complications and protecting the myocardium against acute ischemic events. We investigated the effects of radical scavenger Ginkgo biloba extract EGb 761 against diabetes-induced damage to cardiomyocytes and additional ischemia/ reperfusion injury in spontaneously diabetic BioBreeding/Ottawa Karlsburg (BB/OK) rats, as a model of diabetic myocardium infarction. Morphological and morphometric parameters of heart muscles were analyzed by light and electron-microscopic techniques. We used immunohistochemistry to evaluate parameters of oxidative stress (superoxide dismutase [SOD]) and inducible nitric oxide synthase (iNOS) protein expression. Our results indicated that A) Diabetic myocardium appears more vulnerable to ischemia/ reperfusion damage concerning ultrastructure of cardiomyocytes (sarcomeres, vacuoles, mitochondria), expression of antioxidative enzymes (CuZnSOD, MnSOD), and iNOS than normal myocardium; B) Pretreatment of diabetic myocardium with EGb and additional ischemia/reperfusion leads to a relative improvement in myocardial ultrastructure compared to unprotected myocardium. In summary, EGb appears to be promising as an adjuvant therapeutic drug in diabetics with respect to ischemic myocardium injury. It may contribute to the prevention of late diabetic complications in diabetic cardiomyopathy.
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    Fibroblast remodeling of adsorbed collagen type IV is altered in contact with cancer cells
    (Murcia : F. Hernández, 2008) Maneva-Radicheva, L.; Ebert, U.; Dimoudis, N.; Altankov, G.
    A series of co-culture experiments between fibroblasts and H-460 human lung carcinoma cells were performed to learn more about the fate of adsorbed type IV collagen (Coll IV). Fibroblasts were able to spatially rearrange Coll IV in a specific linear pattern, similar but not identical to the fibronectin (FN) fibrils. Coll IV partly co-aligns with fibroblast actin cytoskeleton and transiently co-localize with FN, as well as with ß1 and a2 integrin clusters, suggesting a cell-dependent process. We further found that this Coll IV reorganization is suppressed in contact with H460 cells. Zymography revealed strongly elevated MMP-2 activity in supernatants of co-cultures, but no activity when fibroblasts or cancer cells were cultured alone. Thus, we provide evidence that reorganization of substrate associated Coll IV is a useful morphological approach for in vitro studies on matrix remodeling activity during tumorigenesis.