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排序方式: 共有230条查询结果,搜索用时 31 毫秒
41.
A retrospective study was performed to characterize 52 new cases of feline epulides between 1995 and 2001, with clinical and pathological results classified according to Head's histopathologic criteria for canine epulides. The incidence of the fibromatous, acanthomatous, ossifying, and giant cell epulis were respectively 57.7% (30/52), 7.7% (4/52), 5.8% (3/52), and 28.8% (15/52). Giant cell epulides presented significant differences in clinical behavior compared with the fibromatous type, including rapid growth (P < .0001), presence of ulcerative changes (P < .01), and rapid recurrence after surgery (P < .01) from which euthanasia was judged necessary in 4 cases. Fifteen giant cell epulides were additionally examined in order to characterize the lesion both histochemically and immunohistochemically and to investigate the origin of the multinucleated giant cells (MGCs). Van Gieson staining showed osteoid and woven bone formation in 11 cases. Both the MGCs and a fraction of the mononuclear cells were positive for vimentin, tartrate-resistant acid phosphatase (TRAP), a commonly accepted marker for osteoclasts, and the polyclonal antibody receptor activator of nuclear factor kappabeta (RANK), a cytokine leading to the differentiation of osteoclast progenitors into mature osteoclasts in presence of its ligand. MGCs were negative for smooth muscle actin, MIB-1, and factor VIII. The giant cell epulis may be a variant of the fibromatous and ossifying epulis in which extensive ulceration and inflammation results in increased osteoclastic activity. The osteoclast-like giant cells are most likely formed from a monocyte/macrophage-like osteoclast precursor that differentiates into osteoclasts under the influence of mononuclear osteoblast-like stromal cells.  相似文献   
42.
Laser-cooled 9Be+ ions confined in two-dimensionally extended lattice planes were directly observed, and the images were used to characterize the structural phases of the ions. Five different stable crystalline phases were observed, and the energetically favored structure could be sensitively tuned by changing the areal density of the confined ions. The experimental results are in good agreement with theoretical predictions for the planar (infinite in two dimensions) one-component plasma. Qualitatively similar structural phase transitions occur, or are predicted to occur, in other experimentally realizable planar systems.  相似文献   
43.
This study hypothesised that different elephant grass genotypes respond differently in terms of their morphological development to irrigation. The objective of this study was to evaluate how water availability could affect the morphological development of different genotypes of elephant grass. The treatments consisted of four genotypes of elephant grass [Cenchrus purpureus (Schumach.) Morrone], managed under irrigation or not, during a two-year field trial. The experiment was arranged in a randomised block design in a split-plot, with four replicates per treatment (n = 4). Between the genotypes, two of them were classified as tall-sized (IRI 381 and Elephant B), and two as dwarfs (Taiwan A-146 2.37 and Mott). A three-way interaction between season, irrigation, and genotype affected the variables plant height, stem diameter, number of dead tillers, light interception (LI), and leaf area index (LAI) (p < .05). The morphological development of all genotypes was negatively impacted by the dry season. All genotypes grew taller during the rainy season (p < .05) and had a greater light interception (62%–80%) compared to the dry period (28%–59%). The genotype Mott, showed comparable LI and LAI to the tall-sized genotypes, whilst Taiwan A-146 2.37 was characterized by the lowest values, despite being the genotype with the greatest tiller density (60 tillers m−2) (p < .05). The use of irrigation mitigated the negative effects of the dry season on the plants, however, the type and size (tall vs. dwarf) of the elephant grass genotypes defined the extent of the responses to the use of the irrigation during the dry period.  相似文献   
44.
Northern scallop Argopecten purpuratus aquaculture relies on an efficient all year-round larval supply. Larvae are generally produced in closed aquaculture systems (CAS) using the batch techniques with periodical water changes. For instance, survival rates are greatly variable and can range from 0 to 80% making production of scallop larvae uncertain. The main goal of this study was to determine the feasibility of rearing scallop larvae in a recirculating aquacultural system (RAS), and secondarily to compare scallop larval growth rate and time length to reach the settling stage when reared with a traditional Chilean CAS technique and in a novel RAS technique in an industrial-like approach.Several batches of larvae were cultured in CAS and RAS. Larvae were fed on Isochrysis galbana cultured in 35-L tubular photobioreactors. Growth rates were significantly different (F11,2840 = 274.66; p < 0.001). All scallop larvae cultured in CAS showed lower growth rates ranging within 4.49 and 7.30 μm day?1 and protracted period of culture until settlement (at least 10 more culture days) than those reared in RAS (growth rates between 9.56 and 13.15 μm day?1). However, final survival (from D-larvae until settlement) of larvae reared in CAS showed higher values than those values recorded for larvae cultured on RAS. Higher growth rates observed in RAS could be attributed to a reduction in daily manipulation of the animals and/or more feed availability as well as higher temperatures and a steady state conditions in water quality. Even though, the reduction in time for rearing larvae until settlement in RAS was high, the comparison between systems is more significant in view of the reduction in make up seawater from 100% of system volume (CAS) to less than 10% of system volume (RAS). Therefore, RAS was independent from daily water quality variation from natural seawater by increasing water retention time, and with that improve water quality steady state conditions. Results of this research show that a more efficient use of water and heating systems than generally used in the Chilean hatchery industry is achievable. This is an important result since it could lead to significant reductions in the cost of operating a scallop hatchery, however further work is required to accurately compare the two systems (CAS and RAS). The main result from this research is that scallop larvae can be cultivated using recirculating aquaculture systems (RAS) as a method to increase production. The information reported in this paper will be useful for the improvement of scallop larvae culture techniques under controlled conditions.  相似文献   
45.
Three-dimensional (3D)/four-dimensional (4D) volume ultrasound is an established method in human medicine that offers various options for analysing and presenting ultrasound volume data. However, the successful application of the different 3D/4D imaging modalities in pregnant dogs and cats has not yet been reported in the literature. The main reasons for this are: (1) the high costs of 3D/4D ultrasound systems, (2) operation difficulties due to high breathing frequency in non-sedated animals and (3) the missing specific knowledge in veterinary medicine concerning how to perform high-quality volume scans. Automatically acquired ultrasound volume data sets were generated with two different ultrasound systems: the portable Voluson i and the stationary Voluson Expert 730. Different 3D/4D imaging modalities were tested in regard of their practicability in pregnancy monitoring in dogs and cats. Nine different volume imaging modalities were applied using the saved files. For the presentation of the static 3D volume data sets, we used the multiplanar, niche, surface, transparency, glass body, inversion, volume calculation and tomographic ultrasound imaging modes. For the dynamic 4D data, the surface and glass body modes were applied. By changing the human standard settings to the requirements of small animal anatomy, it was found that 3D/4D ultrasound has great potential for the characterization of pregnancy in queens and bitches. The 3D/4D technology offered advanced information about pregnancy status and birth prediction and improved the diagnostic confidence. By using standardized examination protocols, 3D/4D ultrasound will allow a reduction in examination time by generating even more relevant information. These benefits, combined with possible future cost reduction of commercial ultrasound systems, might lead to frequent utilization in routine pregnancy diagnostic and birth management in small animal practice.  相似文献   
46.
Four experiments were established on the semi-arid west coast plain of South Africa during the 1990s. The trails tested the survival and growth of several eucalypt species and hybrids, some of which were established in a climate that is drier than their natural distribution range. The aridity indices (AI; defined as mean annual precipitation [MAP]/mean annual potential evapotranspiration) ranged from 0.21 to 0.36 and MAP from 228 to 423 mm. The driest trial site (AI = 0.21 and MAP = 228) had high levels of mortality. However, a number of species (in particular, Eucalyptus gomphocephala, E. camaldulensis and E. tereticornis, as well as individual hybrids of the latter two species with E. grandis) survived and grew well at the remaining sites. Eucalyptus cladocalyx survived well and attained competitive growth rates only on the wettest site in the group (AI = 0.36). The dominant height of the top-performing genotypes at age 5 ranged between 9 and 10 m on the two wetter sites. This corresponded to mean annual increment values in excess of 10 m3 ha?1 a?1, which is comparable to volume obtained at more favourable aridity indices in the summer rainfall zone of South Africa and exceeds the growth rates obtained in several other arid zone studies globally. The E. grandis × E. camaldulensis hybrid ranked among the top performers in two trials, but its susceptibility to recently introduced pests and relatively poor wood quality makes it a less attractive choice for planting. The high density and durability of timber, acceptable growth rate (given the low rainfall conditions), and low pest and disease incidence make E. gomphocephala and E. cladocalyx the species of choice for planting in the drier and relatively wetter sections of the semi-arid zone, respectively.  相似文献   
47.
This report describes a case of cutaneous pythiosis in a 6‐year‐old female mixed breed dog, from the central west region of São Paulo State, Brazil. The cytological and histopathological analyses showed an intense inflammatory infiltrate with presence of numerous hyphal elements, suggesting infection due to Pythium insidiosum. The diagnosis was confirmed by nested‐PCR, which was carried out with specific primers derived from the ribosomal DNA region. The pathogen occurs in Brazil and veterinarians should be aware of the importance of correctly diagnosing this disease and differentiating it from other fungal diseases.  相似文献   
48.
Rotaviruses are the main agents responsible for diarrhea in different animal species and for infantile gastroenteritis. These viruses have been isolated from various avian species and have often been associated with poult enteritis and mortality syndrome. Nevertheless, the knowledge of rotavirus infection in turkeys is scarce. Six group A rotavirus strains obtained from pooled enteric contents of diarrheic turkeys were isolated in MA-104 cell culture and typed as G(6)P(1), a typical bovine rotavirus genotype. Additionally, the electropherotypes showed a migration pattern identical to the Nebraska calf diarrhea virus, and the complete NSP4 gene phylogeny showed that all six strains segregated in the genotype E2. Taken together, these results point toward a cattle-to-turkey rotavirus transmission. As a conclusion, bovine-origin rotavirus can be found in turkeys, and this transmission route must now be considered for the improvement of the health status in turkey farms.  相似文献   
49.
Dogs naturally infected with Leishmania Infantum (=L. chagasi) were treated with miltefosine using different therapeutic regimens. The animals were evaluated for clinical evolution, biochemical parameters, parasite load (by real-time PCR), cytokine levels and humoral response. After treatment and during the following 24 months, there was progressive clinical improvement and complete recovery in 50% (7/14) of the treated animals. There was a decrease in the smear positivity of the bone marrow after treatment, and there was also a gradual and constant decrease in positive cultures at the end of the follow-up period. However, the PCR detection of parasite DNA remained positive. In general, all animals presented a significant increase in parasite load 6 months after treatment. The IFN-γ levels in all the groups tended to increase during follow-up period, regardless of the miltefosine dose administered. The IL-4 and IL-10 levels of the animals tended to decrease during follow-up, except after 300 days when only IL-10 increased. The serum antibodies identified antigens that ranged from 116 kDa to less than 29 kDa in the Western blot assay. Furthermore, 300 days after treatment, qualitative and quantitative differences in the antigen profiles were observed. Antigens of 97 and 46 kDa were the most intensely recognized. Higher levels of antigen-specific Leishmania IgG were detected before and 300 days after treatment in all groups. Taking together, the improvement in the clinical symptoms was not followed by parasitological clearance, suggesting that treatment with miltefosine is not recommended, especially in endemic areas like Brazil, where children are the major victims and dogs are involved in the maintenance of the parasite cycle.  相似文献   
50.
Prolonged hatching egg storage (>7 days) influences internal egg quality and embryo survival during both storage and subsequent incubation. Moreover, effects of storage of hatching eggs interact with the breeder age. The aim of this review was to investigate how this interaction between storage duration and breeder age affects egg, embryo, hatchling and chicken characteristics. Prolonged storage resulted in a reduction in egg quality in both young and old breeders. This reduction was more pronounced in young flocks than in older flocks. For example, albumen pH increased more after 8 days of storage in younger flocks than in older flocks. Additionally, the embryonic morphological stage appears to increase as well with storage duration, but this increase is again more pronounced in younger flocks than in older flocks. Short storage (<7 days) seems to increase hatchability of eggs from young breeders, probably as a result of albumen liquefaction with consequently better oxygen availability for the embryo. However, long storage (>7 days) resulted in a decline in hatchability, which was stronger in older breeders than in younger breeders. Prolonged storage duration resulted in lower chicken quality in both young and old breeders, but interaction between storage duration and breeder age on multiple chicken quality parameters is not clear. Based on this review, it can be concluded that (a) Short storage can improve hatchability of eggs from young breeders, but not from older breeders. (b) Negative impact of long storage appears to be lower with young breeders than with old breeders. (c) Adapted storage conditions related to the age of breeders might be an option to reduce negative effects of prolonged storage on hatching egg quality and chicken quality.  相似文献   
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