A NEW DEVICE FOR STEREOTACTIC CT-GUIDED BIOPSY OF THE CANINE BRAIN: DESIGN, CONSTRUCTION, AND NEEDLE PLACEMENT ACCURACY

An inexpensive device was created for computed tomographic (CT)-guided stereotactic biopsy of the canine brain. The accuracy of the device was tested using 16, formalin-perfused, canine head specimens. For each dog, a 6-inch biopsy needle was guided into pituitary gland and caudate nucleus targets. Needle tracks were measured using the CT computer and infused with tissue staining solution. Hit success and actual needle track lengths were determined from sliced brain specimens. The device enabled accurate orientation and placement of the canine head in the slice plane, such that progressive penetration of the biopsy needle could be monitored. The caudate nucleus was hit 12/16 times (75% accuracy) and the pituitary gland 15.5/16 times (98.6% accuracy). Hit proportions for the two targets did not differ (P < 0.05). A significant difference was found between CT and actual track length for both targets (P < 0.01). This was attributed to incomplete staining of the bevel portion of the needle track.     

A retrospective study into characteristics associated with the seroprevalence of pseudorabies virus-infected breeding pigs in vaccinated herds in the southern Netherlands

Vaccination programs to eradicate pseudorabies virus (PRV) are being considered in several countries. Knowledge of factors that influence PRV transmission within vaccinated breeding herds may contribute to the success of these programs. A multivariate analysis of variance of the PRV-seroprevalence in sows in 209 herds (average seroprevalence 67.0% per herd) in the southern Netherlands revealed the following risk indicators: (1) presence of finishing pigs; (2) production type (producers of finishing piglets had a higher seroprevalence than producers of breeding stock); (3) vaccination of the sows during nursing (in comparison with vaccinating all sows simultaneously at 5 month intervals, or vaccination during the second half of gestation); (4) pig density in the municipality where the herd was located (seroprevalence increased with higher pig density); (5) herd size less than 100 sows; (6) average within-herd parity (seroprevalence increased with higher withinherd parity); (7) replacement pigs raised on the premises; (8) vaccine strain administered to the sows. Purchase policy (breeding pigs purchased between 10 weeks and 7 months of age, or use of home-bred gilts only) did not significantly contribute to the multivariate model.     

Congenital diffuse hyperplastic goiter associated with perinatal mortality in 11 captive-born bottlenose dolphins (Tursiops truncatus).

Diffuse hyperplastic goiter was diagnosed by histopathology in 11 perinatal bottlenose dolphins (Tursiops truncatus) that died at four separate zoos and aquaria. Thyroid morphology of these animals was compared with the histologically normal thyroids of two stranded wild bottlenose dolphin calves, a neonate and a 2-mo-old calf. Histologic changes included reduced follicular luminal diameter, markedly reduced or absent luminal colloid, hypertrophy of follicular epithelium, and follicular dysplasia. The etiology of the thyroid gland lesion was not identified. Cause of death was not determined for most of these animals, but they were presumed to have died from metabolic derangements associated with the thyroid lesion, drowning, or dystocia.     

Detection of Escherichia coli O157:H7 in cattle feces using a polymerase chain reaction-based fluorogenic 5' nuclease (TaqMan) detection assay after secondary enrichment.

Currently, methods for recovering and identifying Escherichia coli O157:H7 from cattle feces are inconsistent and hindered by their inability to specifically and rapidly detect small numbers of organisms from this complex and highly variable matrix. A standard approach for isolating and characterizing E. coli O157:H7 from cattle feces was compared with a polymerase chain reaction (PCR)-based 5' nuclease assay specific for E. coli O157:H7 that included a secondary enrichment step. The PCR-based method proved a better indicator of the presence of the organism than the culture procedure. Retests indicated that the inclusion of a secondary enrichment step and the subsequent analysis by the 5' nuclease assay were reproducible and specific. Escherichia coli O157:H7 could be detected in fecal samples that were otherwise negative after a primary enrichment step, immunomagnetic separation, and plating onto sorbitol MacConkey agar plates containing cefixime and tellurite (CT-SMAC). In samples that were initially identified as culture positive but PCR negative, retesting of the culture isolates on CT-SMAC indicated that the sorbitol fermentation interpretations could frequently not be repeated in retests, whereas retesting using the 5' nuclease assay on the original samples demonstrated a high level of agreement with the initial PCR conclusions. These results indicate the necessity of confirmatory evaluation of isolates culturally recovered by standard cultural methods that involve the interpretation of CT-SMAC. The high level of disagreement between initial culture results and retests, and the high level of agreement between initial PCR results and retests, indicates the advantages of a gene-based detection system for identifying E. coli O157:H7 in cattle feces. Screening large numbers of fecal samples for E. coli O157:H7 would appear to be feasible by integrating the use of enrichment media in serial rounds of incubation with a PCR-based fluorogenic detection procedure in high throughput detection systems that had automated liquid-handling capabilities.     

扬州古运河生态环境林建设研究

从建设中国森林生态网络体系工程的角度 ,结合扬州市古运可综合治理建设 ,就营建扬州古运河生态环境林的指导思想、建设目标、建设原则 ,主要建设模式、建设要求及建设的主要景点和相关研究作了论述     

母马生长激素细胞和催乳激素细胞的形态计测学研究

利用免疫组织化学和形态计测学的方法 ,观察了 1 8匹成熟雌性蒙古马的脑垂体前叶生长激素细胞和催乳激素细胞的数量和面积 ,同时利用放射免疫分析方法检测了这两种激素的血浆水平。结果表明 ,每个马脑垂体前叶中 ,生长激素细胞的平均数量为 6 .42× 1 8,每个细胞的平均面积为 82 .40μm2 ;催乳激素细胞的平均数量为 6 .0 7× 1 0 8,每个细胞的平均面积为 47.31μm2 。生长激素的血浆含量平均为 2 .84ng/ m L,但个体差异较大 ,变异系数高达 78.5 % ,催乳激素的血浆含量平均为 7.2 6 ng/ m L。本研究结果揭示 :母马脑垂体生长激素细胞和催乳激素细胞的数量和面积并不是决定母马这两种激素血中浓度的唯一重要因素 ;生长激素血中浓度上的个体差异 ,可能与其搏动性分泌形式有关     

Coincident scrapie infection and nephritis lead to urinary prion excretion

Prion infectivity is typically restricted to the central nervous and lymphatic systems of infected hosts, but chronic inflammation can expand the distribution of prions. We tested whether chronic inflammatory kidney disorders would trigger excretion of prion infectivity into urine. Urinary proteins from scrapie-infected mice with lymphocytic nephritis induced scrapie upon inoculation into noninfected indicator mice. Prionuria was found in presymptomatic scrapie-infected and in sick mice, whereas neither prionuria nor urinary PrP(Sc) was detectable in prion-infected wild-type or PrP(C)-overexpressing mice, or in nephritic mice inoculated with noninfectious brain. Thus, urine may provide a vector for horizontal prion transmission, and inflammation of excretory organs may influence prion spread.