1,721,364 research outputs found
MORPHOMETRIC AND MOLECULAR STUDIES OF THE CORRELATION BETWEEN CHRONIC MASTITIS AND INFERTILITY IN DAIRY CATTLE
Full text linkDairy cow fertility has declined over the past decades even within the recent developments in functional genomics and genetic selections. There is overwhelming evidence that increasing genetic merit for milk yield considerably reduces fertility and the strength of negative associations between yield and fertility is obviously towards a rising trend. The deterioration of resistance or increased susceptibility to mastitis as well as reduced fertility in today’s cow, are the examples of undesirable side-effects of the high emphasis on production traits in selection decision. Although, recent studies suggested an association between reproductive failure and mastitis in lactating dairy cows, our understanding of how mastitis affects reproduction is still limited. In this context, we investigated the effects of naturally occurring chronic mastitis on fertility particularly at the level of bovine ovarian stroma with matrix fibers, follicular growth factors, characteristic micro-architecture of stromal vasculature, as well as growth and development of follicles by macroscopic and microscopic morphological as well as immuno-detection based molecular analysis of the ovaries collected at slaughter. Ovaries and milk samples were collected from 74 cows at slaughter. Milk samples from each quarter, were analyzed following National Mastitis Council procedures. Following macroscopic assessment, ovaries of 63 animals were scored as healthy, intermediate and pathological. Based on the presence of major pathogens and somatic cell count results, animals were sorted in 9 groups but only the two extremes were considered for further analysis: uninfected (n = 8) and affected by chronic mastitis (n = 9). Primordial, primary and secondary follicles were counted and scored on similar surface area of ovary sections for each animal (mean ± SD= 5.65 ± 0.25 cm2). They were analyzed with Fisher’s exact test and the association between health status and follicle number was estimated by odds ratios ± confidence limits. Stromal cells with matrix collagen fibres were visualized with Masson trichrome staining. Vasculature area in the ovarian cortex of healthy and mastitic animals was identified using Bandeiraea simplicifolia-I (BSL-I) Lectin. Results were quantified with the dedicated software MacBiophotonics image J, NIH, USA and subsequently analyzed with t-test for statistical significance. Follicles were further characterized by immunostaining with a GDF-9 specific antibody. GDF positive follicular area was measured as well as using a relative scale its fluorescence was semi-quantified. Our results indicate no noticeable macroscopic alteration amongst various macroscopic parameters. Similarly, no (P>0.05) difference was observed between the numbers of primordial and primary follicles in healthy and affected animals. In contrast, the number of secondary follicles was significantly lower in sick animals (Odds ratio 10.50*; p<0.05), indicating a 10 times higher risk for a mastitis animal to have less than 2 secondary follicles per square centimeter. In the healthy and mastitic animals the stromal collagen were (1.61±0.90% vs. 6.046±1.85% P<0.001), indicating mastitis is linked with stromal alterations. Ovarian stromal vasculature represented the cortical area of 6.38±0.66 % in healthy vs. 4.24±0.37%; (P<0.001) in affected cows. Likewise, reduced GDF-9 expressed cortical area, healthy vs. sick (1.97±0.83% vs. 1.04±0.11%; P<0.05), with less immuno-fluorescence was observed in mastitic animals. Our results show that chronic mastitis is associated with considerable alterations in follicle growth and differentiation with a decreased ability of primary follicles to develop into the secondary state in affected animals. This is accompanied by a significant increase of stromal collagen with reduced vasculature and the down regulation of the follicle differentiation factor GDF-9. All together, these findings substantiate the hypothesis that mastitis can reduce fertility by exerting a negative effect on ovarian function
Acute phase protein response in Alpine ibex with sarcoptic mange
No full textThe acute phase proteins (APP) are a group of serum proteins that change their concentration in animals following external or internal challenges, such as infection, inflammation or stress. The concentrations of four APPs, including serum amyloid A (SAA), haptoglobin (Hp), α1-acid glycoprotein (AGP) and ceruloplasmin (Cp) were determined in serum collected from healthy Alpine ibexes (Capra ibex) and ibexes with Sarcoptes scabiei mange. Primary structures of all four APPs were determined by cDNA sequencing. The concentrations of all four APPs were higher in serum of animals with clinical signs of sarcoptic mange when compared to healthy animals. Two of the APPs, including SAA and AGP, acted as major APPs, since their serum concentrations were increased more than 10-folds when compared to healthy animals (P < 0.001). The other two APPs, including Hp and Cp, acted as minor acute phase proteins, as their concentrations were increased from two to five folds (P < 0.001).
These findings provide a remarkable potential as diagnostic markers for the early detection of sarcoptic mange in free ranging animals
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
Characterization of the constitutive pig ovary heat shock chaperone machinery and its response to acute thermal stress or to seasonal variations
No full textReduced oocyte competence causes the lower fertility reported in domestic sows during the warm months of the year. Somatic cells express heat shock proteins (HSPs) to protect themselves from damage caused by thermal stress. HSPs are classified as molecular chaperones and control the correct folding of newly synthetized or damaged proteins. Aim of the present work was to perform a comprehensive survey of the different components of the heat shock chaperone machinery in the pig ovary, which included HSP40, HSP70, HSP90 and HSP110 families as well as heat shock factors (HSF) 1 and 2. Pig ovarian follicles constitutively expressed different members of these families therefore we examined their ability to respond to a heat stress. In order to take into account the role of the complex follicular architecture, whole pig ovaries were exposed to 41.5°C for 1 h. This significantly disrupted oocyte maturation and determined the up regulation of HSP70, HSP40, HSPH1, HSPA4, HSPA4L, HSF1, and HFS2 genes whereas HSP90A, HSP90B as well as stress unrelated genes were not altered. Unexpectedly HSPs and HSFs expression changed only in the oocytes but not in the cumulus cells. COCs isolated from ovaries collected in summer and in winter showed the same pattern. We conclude that the HSP chaperone machinery is constitutively fully operational in the pig ovary. However following a thermal stimulus or seasonal variations, cumulus cells HS-related gene expression remains unchanged and only oocytes activate a response, suggesting why this is insufficient to preserve their competence both in vitro and in vivo
TIR8 receptor expression in bovine tissues
No full textThe TIR8 receptor (also called SIGIRR) is an orphan member of the TIR superfamily. Its function is still elusive, but it is believed to trigger a negative pathway of regulation of the Toll-like/IL-1 receptor system, crucial for modulating inflammation in gastrointestinal (GI) tract and in other tissues (lung and kidney). The expression pattern of TIR8 in bovine tissues is unknown.
Given the importance of GI diseases in cattle, the aim of this investigation was to study the distribution of TIR8 in a wide panel of non-pathologic tissues and organs. TIR8 expression was assessed by Northern blot analysis and further confirmed and comparatively quantified by qualitative and quantitative (Real-Time) PCR. The possible presence of tissue-specific isoforms was determined by Western blot immunodetection, using an anti-human TIR8 polyclonal antibody previously validated in bovine tissues. Similarly to humans and mice, bovine TIR8 was found in the GI tract and kidney. Expression of TIR8 mRNA was also detected in lymph nodes, thymus and thyroid gland. Interestingly, several isoforms of bovine TIR8 were detected in the same organs, suggesting the occurrence of different post-translational processings
Large animal models for cardiac stem cell therapies
Full text linkCardiovascular disease is the leading cause of death in developed countries and is one of the leading causes of disease burden
in developing countries. Therapies have markedly increased survival in several categories of patients, nonetheless mortality still
remains high. For this reason high hopes are associated with recent developments in stem cell biology and regenerative medicine
that promise to replace damaged or lost cardiac muscle with healthy tissue, and thus to dramatically improve the quality of life
and survival in patients with various cardiomyopathies.
Much of our insight into the molecular and cellular basis of cardiovascular biology comes from small animal models,
particularly mice. However, significant differences exist with regard to several cardiac characteristics when mice are compared
with humans. For this reason, large animal models like dog, sheep and pig have a well established role in cardiac research. A
distinct characteristic of cardiac stem cells is that they can either be endogenous or derive from outside the heart itself; they can
originate as the natural course of their differentiation programme (e.g., embryonic stem cells) or can be the result of specific
inductive conditions (e.g., mesenchymal stem cells). In this review we will summarize the current knowledge on the kind of
heart-related stem cells currently available in large animal species and their relevance to human studies as pre-clinical models
Reprogramming of Pig Dermal Fibroblast into Insulin Secreting Cells by a Brief Exposure to 5-aza-cytidine
No full textLarge animal models provide useful data for pre-clinical research including regenerative medicine. However whereas the derivation of tissue specific stem cells has been successful. pluripotent stem cells so far have been difficult to obtain in these species. A possible alternative could be direct reprogramming but this has only been described in mouse and human. We have recently described an alternative method for reprogramming human somatic cells based on a brief demethylation step immediately followed by an induction protocol. Aim of the present paper was to determine whether this method is applicable to pig in the attempt to achieve cell reprogramming in a large animal model for the first time. Pig dermal fibroblasts were exposed to DNA methyltransferase inhibitor 5-aza-cytidine (5-aza-CR) for 18 h. After a brief recovery period, fibroblast were subjected to a three-step protocol for the induction of endocrine pancreatic differentiation that was completed after 42 days. During the process pig fibroblast rapidly lost their typical elongated form and gradually became organized in a reticular pattern that evolved into distinct cell aggregates. After a brief expression of some pluripotency genes, cells expression pattern mimicked the transition from primitive endoderm to endocrine pancreas. Not only converted cells expressed insulin but were able to release it in response to a physiological glucose challenge in vitro. Finally they were able to protect recipient mice against streptozotocin-induced diabetes. This work shows, that the conversion of a somatic cell into another, even if belonging to a different germ layer, is possible also in pig. © 2013 Springer Science+Business Media New York
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