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91.
Petrizzi  L.  Ioannoni  A.  Varasano  V.  Russo  V.  Mauro  A.  Mazzola  A. 《Veterinary research communications》2008,32(1):45-50
The ovine foetus is an ideal model for preclinical medical studies of cell therapies. It allows us to follow the behaviour of repairing cells inserted into a favourable physiological microenvironment in an animal species more closely related to humans than the rat or rabbit. In addition, the preimmune foetus is able to support cell engraftment by eliminating the problems of tissue rejection. Labelled fibroblasts were transplanted into the myocardium of preimmune foetuses, injecting through a disposable bowed mouth pipette into the left ventricular apex. Two weeks later, foetuses were isolated by laparotomy and each heart was collected and morphologically analyzed. No cases of abortion or postoperative complications in mothers or foetuses occurred. Macroscopically, the isolated hearts did not display any abnormality apart from a small petechia at the injection site. Tissue sections did not show any sign of acute tissue inflammation and viable labelled cells were easily identified among myocardiocytes. This model system guarantees a reduced damage in the engrafted tissue, a high survival and easy retrieval of the injected cells. The direct injection of cells into the preimmune ovine foetus myocardium can be satisfactorily performed to control tissue delivery and to reduce the risk of cell loss and dispersion.  相似文献   
92.
Determination of serum or plasma progesterone (P4) concentrations is important to recognize pregnant and non-pregnant ewes, and also to predict the number of carried lambs. The 2 most common methodologies for the detection of plasma P4 are radioimmunoassay (RIA) and enzyme immunoassay (EIA). RIA is very expensive, and not all laboratories are equipped to perform this test; EIA is commercially available for human use, but only a few companies produce species-specific kits, which are expensive. We verified for ovine plasma a less expensive and easily available ELISA kit (DiaMetra) designed to quantify P4 in humans. Pools of ovine and human plasma were used to compare repeatability, accuracy, sensitivity, and stability of P4 measured by the DiaMetra kit. Repeatability data were within 15%, and accuracy values were ~90% for both plasma matrices. Stability data showed a loss of <20% for freeze–thaw and <30% for 30-d storage. All parameters were acceptable under international guidelines for method validation. The human ELISA kit was used successfully to quantify plasma P4 in 26 ewes during pregnancy until delivery. P4 concentrations were also correlated with the number of carried lambs.  相似文献   
93.
94.
The cytochrome b (cyt b) gene structure was characterized for different agronomically important plant pathogens, such as Puccinia recondita f sp tritici (Erikss) CO Johnston, P graminis f sp tritici Erikss and Hennings, P striiformis f sp tritici Erikss, P coronata f sp avenae P Syd & Syd, P hordei GH Otth, P recondita f sp secalis Roberge, P sorghi Schwein, P horiana Henn, Uromyces appendiculatus (Pers) Unger, Phakopsora pachyrhizi Syd & P Syd, Hemileia vastatrix Berk & Broome, Alternaria solani Sorauer, A alternata (Fr) Keissl and Plasmopara viticola (Berk & Curt) Berlese & de Toni. The sequenced fragment included the two hot spot regions in which mutations conferring resistance to QoI fungicides may occur. The cyt b gene structure of these pathogens was compared with that of other species from public databases, including the strobilurin-producing fungus Mycena galopoda (Pers) P Kumm, Saccharomyces cerevisiae Meyer ex Hansen, Venturia inaequalis (Cooke) Winter and Mycosphaerella fijiensis Morelet. In all rust species, as well as in A solani, resistance to QoI fungicides caused by the mutation G143A has never been reported. A type I intron was observed directly after the codon for glycine at position 143 in these species. This intron was absent in pathogens such as A alternata, Blumeria graminis (DC) Speer, Pyricularia grisea Sacc, Mycosphaerella graminicola (Fuckel) J Schr?t, M fijiensis, V inaequalis and P viticola, in which resistance to QoI fungicides has occurred and the glycine is replaced by alanine at position 143 in the resistant genotype. The present authors predict that a nucleotide substitution in codon 143 would prevent splicing of the intron, leading to a deficient cytochrome b, which is lethal. As a consequence, the evolution of resistance to QoI fungicides based on G143A is not likely to evolve in pathogens carrying an intron directly after this codon.  相似文献   
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96.
Proximal digital annular ligament (PDAL) desmitis occurs in horses for which PDAL desmotomy is the only reported treatment. The presented work aims to develop a technique for safely performing PDAL desmotomy in horses. Twenty hind limbs and 13 forelimbs, harvested from horses dead or euthanized for reasons unrelated to any structure in the pastern region, were used. All horses were free of disease at the level of their PDAL. Proximal digital annular ligament desmotomy was performed using a minimally invasive approach to the digital flexor tendon sheath between the palmar (plantar) annular ligament and the PDAL, using a medial or a lateral access. Limbs were immediately dissected after the procedure to assess the completeness of the PDAL desmotomy and any possible damage to surrounding structures. The PDAL was successfully transected in all limbs except one. Damage to the surrounding tissue included transection of the palmar digital nerve (n = 1), longitudinal tear of the superficial digital flexor tendon (n = 3), and transection of the ligament of the ergot (n = 21). A medial approach was found to be safer than a lateral approach. In conclusion, PDAL desmotomy can be performed in a safe, repeatable, and technically easy way. This is, to our knowledge, the first report of a standardized technique for performing a PDAL desmotomy in the horse.  相似文献   
97.
Necrotic enteritis in broiler chickens is associated with netB positive Clostridium perfringens type A strains. It is known that C. perfringens strains isolated from outbreaks of necrotic enteritis are more capable of secreting factors inhibiting growth of other C. perfringens strains than strains isolated from the gut of healthy chickens. This characteristic could lead to extensive and selective presence of a strain that contains the genetic make-up enabling to secrete toxins that cause gut lesions. This report describes the discovery, purification, characterization and recombinant expression of a novel bacteriocin, referred to as perfrin, produced by a necrotic enteritis-associated netB-positive C. perfringens strain. Perfrin is a 11.5 kDa C-terminal fragment of a 22.9 kDa protein and showed no sequence homology to any currently known bacteriocin. The 11.5 kDa fragment can be cloned into Escherichia coli, and expression yielded an active peptide. PCR detection of the gene showed its presence in 10 netB-positive C. perfringens strains of broiler origin, and not in other C. perfringens strains tested (isolated from broilers, cattle, sheep, pigs, and humans). Perfrin and NetB are not located on the same genetic element since NetB is plasmid-encoded and perfrin is not. The bacteriocin has bactericidal activity over a wide pH-range but is thermolabile and sensitive to proteolytic digestion (trypsin, proteinase K). C. perfringens bacteriocins, such as perfrin, can be considered as an additional factor involved in the pathogenesis of necrotic enteritis in broilers.  相似文献   
98.
Calorie restriction extends life span in organisms ranging from yeast to mammals. Here, we report that calorie restriction for either 3 or 12 months induced endothelial nitric oxide synthase (eNOS) expression and 3',5'-cyclic guanosine monophosphate formation in various tissues of male mice. This was accompanied by mitochondrial biogenesis, with increased oxygen consumption and adenosine triphosphate production, and an enhanced expression of sirtuin 1. These effects were strongly attenuated in eNOS null-mutant mice. Thus, nitric oxide plays a fundamental role in the processes induced by calorie restriction and may be involved in the extension of life span in mammals.  相似文献   
99.
The evolutionary significance of stress-induced mutagenesis was evaluated by studying mutagenesis in aging colonies (MAC) of Escherichia coli natural isolates. A large fraction of isolates exhibited a strong MAC, and the high MAC variability reflected the diversity of selective pressures in ecological niches. MAC depends on starvation, oxygen, and RpoS and adenosine 3',5'-monophosphate regulons; thus it may be a by-product of genetic strategies for improving survival under stress. MAC could also be selected through beneficial mutations that it generates, as shown by computer modeling and the patterns of stress-inducible and constitutive mutagenesis. We suggest that irrespective of the causes of their emergence, stress-induced mutations participate in adaptive evolution.  相似文献   
100.
A nutritional supplement (Ecotrofin™, by Vetoquinol Italia S.r.l) recommended in ruminants feeding to strengthen the physiological condition and improve digestive performance was tested in 20 pluriparae grazing goats divided in two groups (control and treated) to assess its possible effects on milk yield and quality and to assess eventual adverse effects. Animals from both groups also received 400 g/day of corn meal, and the treated group was supplemented with 20 g/head/day of the nutritional supplement. At the doses suggested by the manufacturer, despite a transient increase after 30 days of supplementation, Ecotrofin™ did not show significant effects on milk yield and, although some changes were found in the fatty acids profile, no significant improvement of MUFA and PUFA, as well as of omega-6:omega-3 ratio and CLA content were seen. Therefore, in our experimental conditions the supplementation of diet with Ecotrofin™ did not appear useful to improve goat's performance. A significant effect on kidney health markers (27 vs. 22.5 for urea and 0.83 vs. 0.76 for creatinine, < 0.05) suggested a beneficial effect on renal function but, since levels fell in the normal ranges in both groups, such hypothesis would need further studies to be addressed.  相似文献   
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