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41.
The long-term changes of the area of Sasa nipponica grassland, bark stripping damage to trees by sika deer, Cervus nippon, and sika deer densities on Mt. Ohdaigahara were assessed with aerial photographs, information from previous studies, and field experiments. The grasslands expanded year after year. The expansion rate was highest from 1982 to 1992, and lowest from 1992 to 1997. Bark-stripping damage on coniferous trees was heavier than that on broadleaf trees in both the early 1980s and 1998. The deer density in the eastern part of the area had been high (14.4–64.3 km−2) from 1984 until 1998. We presume that rich growth of S. nipponica and heavy feeding pressure by sika deer over the long term caused expansion of S. nipponica grasslands by killing canopy trees by bark stripping and preventing forest regeneration.  相似文献   
42.
Inflammasomes play a pivotal role in gastrointestinal homeostasis and inflammation. However, it remains elusive whether the nucleotide-binding oligomerization domain-like receptor (NLR) family inflammasomes, such as NLR family pyrin domain-containing (NLRP) 3, NLRP6, and NLRP12, are involved in the pathogenesis of canine chronic enteropathy (CE), which includes antibiotic-responsive enteropathy (ARE), food-responsive enteropathy (FRE), immunosuppressant-responsive enteropathy (IRE), and non-responsive enteropathy (NRE). Thus, we measured mRNA expression of NLRP3, NLRP6, and NLRP12 in the intestinal mucosa of 35 dogs with CE (ARE, four dogs; FRE, 11 dogs; IRE and NRE, 20 dogs) and seven healthy dogs. As per real-time PCR analysis, significant increases in mRNA expression of NLRP3 and NLRP12 were noted in the colonic but not in the duodenal mucosa of dogs with FRE compared to healthy dogs. These findings suggested that the NLRP3 and NLRP12 inflammasomes might contribute to the development of colitis in dogs with FRE.  相似文献   
43.
We encountered an extremely rare tumor, a pericardial mesothelioma, in a neonatal calf. The patient calf showed severe abdominal distention, and died immediately after birth. The thoracic cavity was contained a huge heart with a large amount of pericardial fluid. A number of granular and cobblestone-like nodules were dispersed over the epicardium and pericardium. The nodules consisted of papillary proliferations of neoplastic cells, and the neoplasm occasionally showed mesenchymal proliferations. Immunohistochemistry revealed that they had the characteristics of mesothelial cells (cytokeratin-and vimentin-positive), and the neoplasm was diagnosed as mesothelioma.  相似文献   
44.
The purpose of present study was to determine annual changes in serum progesterone (P(4)) concentrations and to clarify basic reproductive characteristics, such as breeding season, estrous cycle, and puberty in female bharals (Pseudois nayaur). Blood was collected from 9 female bharals once or twice weekly for approximately one year. Serum P(4) concentrations were determined by radioimmunoassay. Serum P(4) concentrations showed remarkable and cyclic changes between November/December (winter) and May/June (late spring). The mean estrous cycle was 24.9 +/- 0.5 days. Chasing insistently to other females and discharge of mucus from the vulva were observed around the time when the serum P(4) concentrations began to increase. The chasing behavior and discharge of mucus were considered to be external indicators of estrus in female bharals. Serum P(4) concentrations of a pregnant female had non-cyclic changes, and the values remained high. In this study, all 37 deliveries were between April and September, and about 70% of these were concentrated in May and June. The conception month determined on the day of birth was between October and April for all animals, and the most common month was in December (54%). This month corresponded to an early stage of the period when the serum P(4) concentrations changed cyclically. These results indicate that many female bharals become pregnant at the beginning of the breeding seasons and, if they do not become pregnant, the estrous cycle, about 25 days in length, is repeated.  相似文献   
45.
The movement of dislocations in a crystal is the key mechanism for plastic deformation in all materials. Studies of dislocations have focused on three-dimensional materials, and there is little experimental evidence regarding the dynamics of dislocations and their impact at the atomic level on the lattice structure of graphene. We studied the dynamics of dislocation pairs in graphene, recorded with single-atom sensitivity. We examined stepwise dislocation movement along the zig-zag lattice direction mediated either by a single bond rotation or through the loss of two carbon atoms. The strain fields were determined, showing how dislocations deform graphene by elongation and compression of C-C bonds, shear, and lattice rotations.  相似文献   
46.
Somatic cell nuclear transfer (SCNT) has been exploited in efforts to clone and propagate valuable animal lineages. However, in many instances, recipient oocytes are obtained from sources independent of donor cell populations. As such, influences of potential nuclear-cytoplasmic incompatibility, post SCNT, are largely unknown. In the present study, alterations in mitochondrial protein levels were investigated in adult SCNT pigs produced by microinjection of Meishan pig fetus fibroblast cells into enucleated matured oocytes (maternal Landrace genetic background). Mitochondrial fractions were prepared from liver samples by mechanical homogenization and differential centrifugation. Liver mitochondria were then subjected to two-dimensional difference gel electrophoresis (2-D DIGE). Protein expression changes were confirmed with a volume ratio greater than 2 fold (P<0.05). 2-D DIGE analysis further revealed differential expression of three proteins between the Meishan (n=3) and Landrace (n=3) breeds. Differential expression patterns of 16 proteins were detected in SCNT pig liver tissue (n=3) when compared with Meishan control samples. However, none of the 16 proteins correlated with the three differentially expressed Meishan and Landrace liver mitochondrial proteins. In summary, alteration of mitochondrial protein expression levels was observed in adult SCNT pigs that did not reflect the breed difference of the recipient oocytes. Comparative proteomic analysis represents an important tool for further studies on SCNT animals.  相似文献   
47.
A 9-year-old spayed female domestic shorthair cat presented with a skin lesion of the left tarsus. The lesion was biopsied and, based on the microscopic appearance and immunohistochemical characteristics, histiocytic sarcoma was diagnosed. Amputation was performed with improved demeanor seen postoperatively. However, between 44 and 60 days following the surgery, relapse of skin lesions appeared in multiple locations, including at the previous amputation site, and euthanasia was elected. This is the first report of a histiocytic sarcoma treated with amputation in a cat.  相似文献   
48.
The db/db mouse is one of the diabetes mellitus animal models and if the pathophysiological stages of diabetic changes in the mouse model could simulate the stages in human diabetes, the db/db mouse could be used to better evaluate drug candidates. Blood insulin, HbA1c levels and morphological features of pancreatic islets in db/db mice were evaluated to determine the pathophysiological stage. At 6 weeks of age, db/db mice showed the highest level of plasma insulin and lowest level of HbA1c, and histopathological examination revealed enlarged islets with a circular shape and hypertrophic islet cells. By 9 and 12 weeks of age, the plasma insulin levels had decreased to mid levels and HbA1c had increased to mid to high levels; histopathological examination at this time revealed two types of islets coexisting, enlarged circular islets and small irregular-shaped islets. By 15 and 22 weeks of age, plasma insulin had decreased further to low levels and HbA1c was at its highest level; the histopathological examination at this time revealed an increase in irregular-shaped and small islets. Based on blood insulin levels, HbA1c levels and histopathology findings in the db/db mice in this study, the clinical staging of diabetic changes were recognized. The pathophysiological stages of diabetes mellitus in this animal model were similar to the stages in humans.  相似文献   
49.
In order to determine insulin secretability and glucose utilization, a glucose tolerance test was performed in ateliotic cattle of 2 paternal strains; MHO and HSK cattle. MHO and HSK cattle showed different endocrine patterns in our previous study. Area under the insulin concentration curves (insulin-AUC) in the ateliotic cattle were significantly lower (122.3 +/- 59.4 ng.min/ml and 99.2 +/- 24.8 ng.min/ml for MHO and HSK cattle, respectively) than the control cattle (420.2 +/- 175.2 ng.min/ml). These low insulin responses to GTT may have an influence on growth retardation in MHO and HSK cattle.  相似文献   
50.
Cloning and expression of canine interferon-alpha genes in Escherichia coli   总被引:1,自引:0,他引:1  
We cloned five new subtypes of cDNA encoding canine interferon-alpha (CaIFN-alpha) from a canine epithelial cell line. CaIFN-alphas were divided into two groups by amino acid sequences and a molecular phylogenic tree. Two subtypes of them were expressed in Escherichia coli, and IFN proteins were purified. Recombinant CaIFN-alphas were highly species-specific and showed antiviral activity against Vesicular stomatitis New Jersey virus and canine adenovirus-1 , but not against canine herpesvirus-1.  相似文献   
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