Histology and histopathology Vol.22, nº10 (2007)

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    Current concepts in human prion protein (Prp) misfolding, Prnp gene polymorphisms and their contribution to Creutzfeldt-Jakob Disease (CJD)
    (Murcia : F. Hernández, 2007) Michalczyk, K.; Ziman, M.
    Transmissible spongiform encephalopathies are a group of neural degenerative diseases that may be infectious, sporadic, or hereditary and are associated with an abnormally folded prion protein. Unfortunately at the current time it is not at all clear what the normal structure of the prion protein actually is or how it is toxic to cells. Extensive research on prion diseases has led to a dramatic increase in understanding of the pathogenesis of prion disorders, which will hopefully lead to the development of effective treatments. The inability to detect the disease in blood using current technology has made screening difficult. While fortunately there has been a decline in the number of clinical cases of transmissible variant CJD, evidence indicates that very long incubation periods can occur in humans so there may be a long slow, gradual epidemic. In particular, clinical cases in genotypes other than those homozygous for methionine at codon 129 of PRNP have not yet occurred, but such cases might be expected to have longer incubation periods and show differences in pathology to those seen to date. proportion of infected animals develop sub-clinical disease. Moreover, results from a large prevalence study in humans show that several cases test positive but do not develop clinical disease. It is possible therefore that further cases of secondary transmission could occur by iatrogenic spread, which could result in vCJD persisting in the UK at low levels for many years, highlighting the importance of continued vigilance.
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    Experimental change on dopaminergic neurons in striatum of Parkinson disease rats
    (Murcia : F. Hernández, 2007) Chen, X.Y.; Li, Jiang; Qi, W.Q.; Shen, S.H.
    Background: Parkinson’s disease (PD) is a common neurodegenerative disorder characterized by selective and progressive demise of dopaminecontaining neurons in the midbrain. In this study, we observe the expression of c-Jun in the striatum of rats with 6-hydroxydopamine (6-OHDA)-lesions after apomorphine (APO) intraperitoneal injection (ip) in substantia nigra compacta (SNc), and to study the mechanism of the rotations behavior. Design: The 6- OHDA was unilaterally injected into rat right SNC. The APO- induced abnormal rotations were investigated on the 1st, 4th, 7th, 14th, 21st days after lesion, respectively. Meanwhile dopaminergic degeneration and c-Jun expression were observed with microscope. Nissl’s body staining and immunohistochemical method (ABC) were employed to study the changes of tyrosine hydroxylase (TH) and c-Jun in DA neurons. Results: We found that the number of dopaminergic neurons decreased gradually in the lesioned site and those neurons’ electron-microscopic structure was severe damaged. There were over 75% of dopaminergic neurons lost, contralateral rotations over 7 turns per minute and c-Jun expressing in the ipsilateral striatum. Conclusion: Dopaminergic neurons deletion may be linked to upregulation of c-Jun.
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    Histomorphometric study of femoral heads in hip osteoarthritis and osteoporosis
    (Murcia : F. Hernández, 2007) De Pedro, J.A.; Martin, A.P.; Blanco, J.F.; Salvado, M.; Perez, M.A.; Cardoso, A.; Collía, F.; Ellis, S.S.; Domínguez, J.
    During the period from 2000 to 2003, ninety eight samples of femoral heads were collected. In these pieces, two zones were analyzed: a high-load zone (the hard core of the head) and a low-load zone (the round ligamentum teres zone). As control group, 6 femoral heads (3 of women and 3 of men), proceeding from autopsy in peoples without pathological antecedents and youngs, were studied. After the samples had been embedded in methylmethacrylate and stained, they were subjected to an histomorphometric study. By means of histomorphometry, trabecular bone volume (TBV) and osteoid substance (OSV) was determined. Statistically significant differences were found as for peripheral osteoid volume (low-load zone) ( p=0.036) and trabecular bone volume, both peripheral and central. Both volumes decreased in osteoporotic samples and in those from women (p=0.000), in comparison with control group. Regarding the relationship between the high-load and low-load zone, significant data were obtained. The high-load zone had a greater trabecular bone volume than the low-load zone, regardless of the pathology and sex, but this increase was more pronounced in the arthrosic samples and in those from men. Additionally, this trabecular bone volume in the high-load zone decreased with increasing age of the donor (p=0.037), when the control group is compared. In sum, we observed a reduction in the formation of TBV and OSV in osteoporosis but also a decrease in the arthrosic, in samples from older subjects, in women, and in the low-load zone of the samples, when the control group is compared. These data suggest the coexistence of both pathologies, which is more pronounced in older subjects and women.
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    Occurrence of two NOS isoforms in the developing gut of sea bass Dicentrarchus labrax (L.)
    (Murcia : F. Hernández, 2007) Pederzoli, A.; Conte, A.; Tagliazucchi, D.; Gambarelli, A.; Mola, L.
    In this work we have examined the appearance and distribution of nitric oxide synthase (NOS), with histochemical, immunohistochemical and biochemical methods, during development of the sea bass (Dicentrarchus labrax) gut. The data showed that both the calcium-calmodulin dependent neuronal isoform (nNOS) and calciumindependent inducible isoform (iNOS) are present in the larval gut of sea bass. The nNOS-immunoreactivity was present in the epithelial cells and enteric nerve cells of gut both in the 8-day-old specimens and in the 24-dayold- larvae. In the adult nNOS-immunoreactivity disappeared from epithelial cells, remaining in the wall intramural neurons and fibers. The iNOSimmunoreactivity was present in the epithelial cells of 24-day-old-larvae and was not detectable in the adult gut. Western blot analysis and determination of NOS activity also demonstrated the presence of the two NOS isoforms, nNOS and iNOS, in the gut of 24-day-old specimens. The presumably different roles played by the two isoforms of enzyme are discussed. The presence of nNOS isoform in the gut enteric neurons of the same larval stages of D. labrax in which we previously demonstrated the presence of substance P and Vasoactive Intestinal Polypeptide (VIP), may suggest that all these three components of the motility control system are already present in the larval phase. Nitric oxide (NO) may be also involved in the early immune response. The present results on the occurrence of iNOS isoform in epithelial gut cells of the same regions in which the gut-associated lymphoid tissue (GALT) will differentiate, may suggest for NO a role in early defence mechanisms, before the establishment of immune responses in GALT. Finally, the developmental and regional differences in nNOS and iNOS expession also suggest a regulatory role in development and differentiation of the sea bass gut.
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    The melanogenic system of the liver pigmented macrophages of Rana esculenta L. - Tyrosinase activity
    (Murcia : F. Hernández, 2007) Gallone, A.; Sagliano, A.; Guida, G.; Ito, S.; Wakamatsu, K.; Capozzi, V.; Perna, G.; Zanna, P.; Cicero, R.
    The enzyme system responsible for Amphibian Kupffer Cell (KC) melanogenesis has not been entirely elucidated. This research demonstrates that the KC melanosomes of Rana esculenta L. possess a tyrosine-hydroxylase (TH) activity, showing that a tyrosinase is the enzyme involved in the melanogenesis. The TH reaction depends on catalytic Dopa as a cofactor and is not affected by catalase or H2O2, showing that it is catalysed by the tyrosinase and not by the peroxidase present in the melanosomes. The TH reaction is activated by Cu2+ ions but not by other tyrosinase activators such as limited proteolysis, protein ageing, and Sodium Dodecyl Sulphate (SDS). SDS inhibited the KC TH activity even below the critical micelle concentration. All these results suggest that the KC-tyrosinase differs in structure from other known tyrosinases. Using anti-KC-tyrosinase antobodies, we observed that the sites of the tyrosinase location within the cell are the same as those described in the melanocytes. In the immunoblots, the anti-KC-tyrosinase antibodies also recognised two protein bands, at the higher molecular weight ranges, in the protein electrophoretic pattern. Moreover, the tyrosinase activity was limited to the highest molecular weight band of about 260 kDa, suggesting that the enzyme activity could depend on a molecular aggregate. The melanin produced in the liver was found to be a 5,6-dihydroxyindole-rich eumelanin similar to the Sepia melanin.