1,721,026 research outputs found
Distribution of heat shock proteins in kidneys of rats after immunosuppressive treatment with cyclosporine A
No full textCyclosporine A (CsA), a fungal undecapeptide, is the most common immunosuppressive drug used in organ transplantation and auto-immune diseases. However, it has severe side effects mainly on renal structures and functions. Therefore, nephrotoxicity is the major limiting side effect. Heat shock proteins (HSPs) are molecular chaperones, that are induced or expressed at high levels in mammalian cells due to a variety of adverse effects. HSPs have beneficial roles in protein processing and protection against cell injury. In the present study, we examined immunohistochemically levels of expression and localization patterns of various HSPs in rat kidneys after administration of a therapeutic CsA dose during 30 days. After CsA treatment, both constitutive HSP 25 and alpha B-crystallin immunoreactivity became stronger in glomeruli, proximal tubules and collecting ducts. Nuclear translocation of these proteins was detected in renal tubules. HSP 47 was detected in the interstitial space between tubules, vascular smooth muscle and medullary rays. Finally, HSP 72 was induced in the cytoplasm of epithelial cells of proximal and distal tubules, and in the cytoplasm of epithelial cells of Henle limbs and collecting ducts. These data demonstrate that CsA clearly induces increased immunoreactivity of HSPs in defined structures of rat kidneys. These findings suggest that these proteins are functionally involved in the defence against renal cellular damage caused by prolonged drug treatment in rat
Cytoplasmic changes in satellite cells of spinal ganglia induced by cisplatin treatment in rats
No full textThe effects of cisplatin (cis-DDP) therapeutic treatment on the cytoplasmic compartment of satellite cells (SC) of rat dorsal root ganglia (DRG) were evaluated. Female Wistar rats were treated once a week with i.p. injection of cis-DDP (2 mg/kg) for 9 weeks. Morpho-quantitative changes of the cytoplasmatic organelles in SC cytoplasm from L4-L6 DRG were determined at the electron microscopic level. The quantitative changes in the lysosomal system components called dense bodies (DB) and in the mithocondria were stereologically evaluated. The data from SC were compared to those from the neurons. The cis-DDP treatment induced a great increase in DB and mithocondria volume of SC. Furthermore, the SC sheath showed an increase of the cytoplasmic lamellar expansions responsible of the physical dissociation of SC sheath from the nerve cell body surface. The comparative analysis from SC and neurons showed that the drug affected primarily the SC, supporting the idea that SC could be the initial target of cis-DDP molecule. The alterations of the anatomical relationships between SC and neurons could modify the cell control on extracellular solutions, altering the functional role barrier attributed to SC. It appears that not only the DRG neurons but also and principally the SC were involved in the peripheral neuropathy mechanisms caused typically from therapeutic cis-DDP administration
Cyclosporine A-induced kidney alterations are limited by melatonin in rats : an electron microscope study
No full textThe effect of melatonin on experimental prolonged cyclosporine A (CsA) nephrotoxicity was analyzed by electron microscopy and morphometry. Twenty female Wistar rats were divided into groups that received (1) CsA at a therapeutic dose (15 mg/kg/day) sc for 40 days; (2) olive oil, CsA vehicle, as controls; (3) CsA plus melaton (1 mg/kg) ip for the same time; (4) melatonin alone, as additional controls. All controls had normal renal ultrastructure. However, in CsA group, both tubular and glomerular alterations were observed. The authors found apoptotic and necrotic proximal tubules with disrupted brush border, swollen mitochondria, abundant lysosomes; in the glomerulus, amorphous basement membrane, and abnormal mesangial matrix. CsA plus melatonin administration partly prevented these changes. Nevertheless, fibrillar deposits in podocytes and basolateral membrane dilatations in proximal tubules were observed. Histopathological analysis on semithin sections and ultrastructural morphometry were also performed. CsA induced interstitial fibrosis, atrophy, and PAS positive inclusions in the proximal tubules. Moreover, CsA reduced glomerular and mesangial volume but enhanced mesangial matrix volume and basement membrane thickness. After CsA plus melatonin, these parameters were reduced in the proximal tubules and restored in the glomerulus. In conclusion, melatonin attenuated morpho-quantitative alterations induced by CsA in the rat kidney
APOPTOTIC MOLT-4 LYMPHOBLASTIC LEUKEMIA CELLS CAN BE DETECTED BY FLOW CYTOMETRY IN THE ABSENCE OF NUCLEOSOMAL DNA FRAGMENTATION
No full textSmall heat shock proteins expression in rat kidneys treated with cyclosporine A alone and combined with melatonin
No full textSmall heat shock proteins (sHSPs) are cytoskeletal chaperones constitutively expressed in the normal kidney but enhanced with beneficial roles during adverse stimuli. Cyclosporine A is an immunosuppressive drug with major adverse side effect such as severe nephrotoxicity. Among possible mechanisms of cyclosporine A-induced renal damage, oxidative stress and cytoskeletal damage have been suggested. Melatonin has been successfully used as antioxidant against many renal diseases. This in vivo study was performed to shed light on the protective effect of melatonin against cyclosporine A-induced renal alterations. We treated rats with cyclosporine A alone, or combined with melatonin, and with melatonin alone (as controls) for 40 days and analysed the renal abundance and distribution of two sHSPs, HSP25 and alpha B-crystallin. These data were correlated with the histopathological effects of the treatments. Cyclosporine A induced insoluble isoforms that moved to soluble fractions after melatonin coadministration as in controls. After cyclosporine A treatment, an intense signal for sHSPs was found within the glomeruli, nucleus and cytoplasm of cortical tubules, collecting ducts and vascular wall. After melatonin supply, the staining was faint, limited to the cytoplasm of cortical tubules, similar to controls. Both fibrosis and tubular alterations significantly decreased after melatonin coadministration. In conclusion, HSP25 and alpha B-crystallin are overexpressed in the rat kidney treated with cyclosporine A but are similar to controls after combined melatonin. This could be a consequence of the cytoprotective effect of melatonin in this nephrotoxic model so that a beneficial sHSPs response is unnecessary
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Impact of melatonin on skeletal muscle and exercise
Full text linkSkeletal muscle disorders are dramatically increasing with human aging with enormous
sanitary costs and impact on the quality of life. Preventive and therapeutic tools to limit the onset and
progression of muscle frailty include nutrition and physical training. Melatonin, the indole
produced at nighttime in the pineal and extra-pineal sites in mammalians, has recognized anti-aging,
anti-inflammatory, and anti-oxidant properties. Mitochondria are the favorite target of melatonin,
which maintains them efficiently, scavenging free radicals and reducing oxidative damage. Here,
we discuss the most recent evidence of dietary melatonin efficacy in age-related skeletal muscle
disorders in cellular, preclinical, and clinical studies. Furthermore, we analyze the emerging impact
of melatonin on physical activity. Finally, we consider the newest evidence of the gut–muscle axis
and the influence of exercise and probably melatonin on the microbiota. In our opinion, this review
reinforces the relevance of melatonin as a safe nutraceutical that limits skeletal muscle frailty and
prolongs physical performance
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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