1,720,973 research outputs found
Oxidative stress in the pathogenesis of canine zinc-responsive dermatosis
No full textZinc deficiency causes skin diseases both in humansand in animals. The underlying pathogenic mechanismsremain unclear, but a growing body of evidenceindicates a role for zinc in skin protectionagainst free radical-induced oxidative damage. Theimmunohistochemical expression of heat shock proteins(HSPs; Hsp27, Hsp72, Hsp73 and Hsp90), Cu⁄ Znsuperoxide dismutase (SOD), metallothionein (MT),Ki-67 antigen and active caspase-3 were evaluated innormal canine skin and in samples from eight dogswith zinc-responsive dermatosis. All investigatedHSPs showed intense cytoplasmic immunostainingin the affected epidermis. Focal nuclear positivity ofHsp72 was also detected in keratinocytes. AlthoughCu ⁄ Zn SOD expression was similar to that observedin normal skin, MT immunoreactivity occurred inboth the cytoplasm and the nucleus of basal cells innormal skin but was absent from the affected epidermis.Caspase-3 activation was also absent in theinvolved epidermis, which revealed a high Ki-67index (a 3.5- to 9-fold increase compared with normalskin). These results support the hypothesis that cellularresponse to stress, particularly oxidative stress, isinvolved in the pathogenesis of skin lesions in caninezinc-responsive dermatosis. The lack of MT immunoreactivityin the affected epidermis may be indicativeof low zinc levels, thus resulting in vulnerability tooxidative damage. In contrast, high expression levelsof HSPs in skin during zinc deficiency may conferprotection against a variety of dangerous stimuli,contributing to inhibition of apoptosis and to cellcycle regulation of proliferating keratinocytes.[...
OXIDATIVE STRESS IN THE PATHOGENESIS OF CANINE ZINC-RESPONSIVE DERMATOSIS
No full textZinc deficiency causes skin diseases both in humans and in animals. The underlying pathogenic mechanisms remain unclear, but a growing body of evidence indicates a role for zinc in skin protection against free radical-induced oxidative damage. The immunohistochemical expression of heat shock proteins (HSPs; Hsp27, Hsp72, Hsp73 and Hsp90), Cu ⁄ Zn
superoxide dismutase (SOD), metallothionein (MT), Ki-67 antigen and active caspase-3 were evaluated in normal canine skin and in samples from eight dogs with zinc-responsive dermatosis. All investigated HSPs showed intense cytoplasmic immunostaining
in the affected epidermis. Focal nuclear positivity of Hsp72 was also detected in keratinocytes. Although Cu ⁄ Zn SOD expression was similar to that observed in normal skin, MT immunoreactivity occurred in both the cytoplasm and the nucleus of basal cells in normal skin but was absent from the affected epidermis. Caspase-3 activation was also absent in the involved epidermis, which revealed a high Ki-67 index (a 3.5- to 9-fold increase compared with normal skin). These results support the hypothesis that cellular response to stress, articularly oxidative stress, is involved in the pathogenesis of skin lesions in canine zinc-responsive dermatosis. The lack of MT immunoreactivity in the affected epidermis may be indicative
of low zinc levels, thus resulting in vulnerability to oxidative damage. In contrast, high expression levels of HSPs in skin during zinc deficiency may confer protection against a variety of dangerous stimuli, contributing to inhibition of apoptosis and to cell cycle regulation of proliferating keratinocytes
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
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
Possible role of oxidative stress in the pathogenesis of canine zinc-responsive dermatosis
No full textIntroduction: Zinc deficiency causes skin diseases in humans and animals but the underlyingpathogenic mechanisms still remain unclear. There is a growing body of evidence for therole of zinc in protecting skin against free radical-induced oxidative damage. Zinc ions mayinduce the synthesis of metallothioneins (MTs), sulfhydryl-rich proteins that store zinc and actas free radical scavengers. Cu/Zn superoxide dismutase (SOD) is also important for skin healthas a result of its antioxidant activity. Skin represents a major target for various environmentalstress agents able to induce synthesis of Heat Shock Proteins (HSPs) or Stress Proteins, whichare one of the most evolutionarily conserved classes of molecules playing a crucial role inthe maintenance of cellular homeostasis. A large number of studies have also demonstratedthe anti-apoptotic activity of several HSPs, that usually show elevated levels in proliferatingmammalian cells and cell cycle-dependent expression.Material and methods: The study was carried out on biopsy samples of canine zinc-responsivedermatosis from 8 Siberian Huskies and necropsy samples of normal skin from different sitesfrom 5 Siberian Huskies (excluding sites of frequent mechanical trauma but including thosewhere zinc-responsive dermatosis commonly occurs). Samples were fixed in 10% neutralbuffered formalin and embedded in paraffin wax. The immunohistochemical expression ofHsp27, Hsp72, Hsp73, Hsp90, Cu/Zn SOD, MT, Ki-67 and active caspase-3 were evaluatedusing a streptavidin-biotin-peroxidase technique. Ki-67 labelling index (KI) was calculated asthe percentage of positive nuclei divided by the total number of keratinocytes examined. Atleast 1000 keratinocytes per specimen were examined in ten randomly selected fields usinglight microscopy (x400).Results: All investigated HSPs showed intense cytoplasmic immunostaining in the affectedepidermis. Focal nuclear positivity of Hsp72 was also detected in isolated keratinocytes. AlthoughCu/Zn SOD expression was similar to that observed in normal skin, MT immunoreactivity wasrevealed in both the cytoplasm and nucleus of basal cells in normal skin but lacked in theaffected epidermis. Caspase 3 activation was also absent in the involved epidermis, whichrevealed a high Ki-67 index (a 3.5- to 9-fold increase compared to normal skin).Discussion: The results of this study support the hypothesis that cellular stress response, inparticular response to oxidative stress, is involved in the pathogenesis of skin lesions occurringin canine zinc-responsive dermatosis. The lack of MT immunoreactivity in the affectedepidermis may be indicative of low zinc levels, thus resulting in vulnerability to oxidativedamage. On the other hand, high levels of HSP expression in skin during zinc deficiency mayconfer protection against a variety of dangerous stimuli, contributing to inhibition of apoptosis,as well as to cell cycle regulation of proliferating keratinocytes. Detection of nuclear Hsp72expression in affected keratinocytes is consistent with its involvement in protection of thenucleus and repair of DNA damage, particularly induced by UV light exposure.[...
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Cutaneous epitheliotropic lymphoma: clinico-pathological features in 20 dogs
No full textIntroduction - Canine epitheliotropic cutaneous lymphoma, also named mycosis fungoides, has been described as an uncommon cutaneous lymphoma of T-cell origin, which is histologically characterized by the epitheliotropism of neoplastic T-lymphocytes. Two variants have been reported in man, based upon clinical and histopathological features: classical mycosis fungoides and Sezary syndrome. The disease in dogs is clinically classified as cutaneous nodular form, exfoliative erythroderma, mucocutaneous form, and oral form. Aim of the study - The aim is to point out the most interesting clinical and histopathological findings for the diagnosis, also carrying out a comparison with the human species. Material and methods - We report the cases of 20 dogs, diagnosed with epitheliotropic cutaneous lymphoma. Medical records of these animals were reviewed for rilevant data on signalment, anamnesis, clinical examination and histopathologic diagnosis. Results - All the clinical variants described by Scott in veterinary medicine were present alone or in combination: exfoliative erythroderma (75% dogs), mucocutaneous form (65% dogs), cutaneous nodular form (55% dogs), and oral form (25% dogs). On the basis of histological features, the most represented variant was pagetoid reticulosis (14/20 dogs, 70%). Sezary syndrome could not be found. Discussion - The clinical and histopathological features that were observed reflected those previously reported in the published literature, and showed interesting findings to be compared with the homologous human neoplasia
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