An in vitro biomechanical comparison of the insertion variables and pullout mechanical properties of ao 6.5-mm standard cancellous and 7.3-mm self-tapping, cannulated bone screws in foal femoral bone     

Johnson NL  Galuppo LD  Stover SM  Taylor KT 《Veterinary surgery : VS》2004,33(6):681-690

OBJECTIVE: To compare screw insertion variables and pullout mechanical properties between AO 6.5-mm cancellous and 7.3-mm cannulated bone screws in foal femoral bone. STUDY DESIGN: A paired, in vitro mechanical study. SAMPLE POPULATION: Seven pairs of femora from immature (1-7 months) foals. METHODS: The 6.5 cancellous and 7.3-mm cannulated screws were inserted at standardized proximal and distal metaphyseal, and mid-diaphyseal locations. Insertion torque, force, and time to drill, tap (6.5-mm cancellous), guide wire insertion (7.3-mm cannulated), and screw insertion were measured. Screw pullout properties (yield and failure load, displacement, and energy, and stiffness) were determined from mechanical tests. The effects of screw type and location on insertion variables and pullout properties were assessed with repeated measures ANOVA. Pairwise comparisons were examined with post hoc contrasts. Significance was set at P<.05 for all comparisons. RESULTS: Insertion torques for the 7.3-mm cannulated screws were significantly greater than for the 6.5-mm tap, but significantly lower than for the 6.5-mm cancellous screws. Total screw insertion times were similar. Pullout properties of both screws were similar at each femoral location. The holding power of both screws was significantly greater in the mid-diaphysis than in either metaphyseal location. Pullout failure occurred by bone shearing at the bone-screw interface in all specimens. CONCLUSIONS: The 6.5-mm cancellous and 7.3-mm cannulated screws vary in insertion properties, but have similar pullout properties in the mid-diaphysis, proximal, and distal metaphysis of foal femora. Both screw types have greater holding power at the mid-diaphyseal location compared with metaphyseal locations. Based on overall similar holding powers of 6.5-mm cancellous and 7.3-mm cannulated screws, it is unlikely that increasing the screw diameter beyond 6.5 mm will provide increased holding power in foal femoral bone. CLINICAL RELEVANCE: Use of the 7.3-mm cannulated screw should be considered for foal femoral fracture repair when greater accuracy is needed, or when bone threads for the 6.5-mm cancellous screw have been stripped.  相似文献   

Changes in interleukin-6 concentration in peripheral blood of pre- and post-partum dairy cattle and its relationship to postpartum reproductive diseases     

Ishikawa Y  Nakada K  Hagiwara K  Kirisawa R  Iwai H  Moriyoshi M  Sawamukai Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(11):1403-1408

Reproductive diseases after parturition are a serious problem in dairy cattle. It is important to predict postpartum reproductive diseases early and to develop prophylaxis. The objectives of this study were to demonstrate changes in the peripheral blood concentration of interleukin-6 (IL-6) before parturition, which was mainly produced by T helper 2 type (Th2) cells, and to investigate a correlation between the IL-6 concentration and the occurrence of the postpartum retained placenta, endometritis and/or follicular cyst in dairy cattle. Twenty-seven Holstein-Friesian cows were used for this study. Thirteen had no clinical disease, 8 had retained placenta, 4 were diagnosed with endometritis by vaginal inspection, and 2 were diagnosed with follicular cyst by rectal palpation at 1 and 2 months after parturition. Blood samples were collected 60 days pre- and post-partum. They used for IL-6, progesterone (P(4)) and estradiol-17beta (E(2)) concentration determination. This study showed that the IL-6 concentration prepartum was higher than postpartum. Low levels of IL-6 and P(4) in peripheral blood prepartum tended to affect retained placenta and a high level of IL-6 prepartum tended to affect endometritis. These results indicate that measurement of change in the IL-6 concentration during pregnancy is one useful tool for predicting crisis in postpartum reproductive diseases in dairy cattle.  相似文献   

Effects of Central Kalimantan plant extracts on intraerythrocytic Babesia gibsoni in culture     

Subeki  Matsuura H  Yamasaki M  Yamato O  Maede Y  Katakura K  Suzuki M  Trimurningsih  Chairul  Yoshihara T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2004,66(7):871-874

The inhibitory effects of 45 plant extracts selected from Central Kalimantan, Indonesia on Babesia gibsoni in vitro and their acute toxicity to mice were evaluated. Of these plant extracts studied, Arcangelisia flava, Curcuma zedoaria, Garcinia benthamiana, Lansium domesticum and Peronema canescens were found to have appreciable antibabesial activity with IC50 values from 5.3 to 49.3 microg/ml without acute toxicity in mice at the intraperitoneal dose of 0.7 g/kg of body weight.  相似文献   

Selection of scale for Everglades landscape models   总被引：3，自引：0，他引：3  

Jayantha Obeysekera  Ken Rutchey 《Landscape Ecology》1997,12(1):7-18

This article addresses the problem of determining the optimal “Model Grain” or spatial resolution (scale) for landscape modeling in the Everglades. Selecting an appropriate scale for landscape modeling is a critical task that is necessary before using spatial data for model development. How the landscape is viewed in a simulation model is dependent on the scale (cell size) in which it is created. Given that different processes usually have different rates of fluctuations (frequencies), the question of selection of an appropriate modeling scale is a difficult one and most relevant to developing spatial ecosystem models. The question of choosing the appropriate scale for modeling is addressed using the landscape indices (e.g., cover fraction, diversity index, fractal dimension, and transition probabilities) recently developed for quantifying overall characteristics of spatial patterns. A vegetation map of an Everglades impoundment area developed from SPOT satellite data was used in the analyses. The data from this original 20 × 20 m data set was spatially aggregated to a 40 × 40 m resolution and incremented by 40 meters on up to 1000 × 1000 m (i.e., 40, 80, 120, 160 … 1000) scale. The primary focus was on the loss of information and the variation of spatial indices as a function of broadening “Model Grain” or scale. Cover fraction and diversity indices with broadening scale indicate important features, such as tree islands and brush mixture communities in the landscape, nearly disappear at or beyond the 700 m scale. The fractal analyses indicate that the area perimeter relationship changes quite rapidly after about 100 m scale. These results and others reported in the paper should be useful for setting appropriate objectives and expectations for Everglades landscape models built to varying spatial scales.  相似文献   

Evaluation of the California mastitis test to detect an intramammary infection with a major pathogen in early lactation dairy cows   总被引：1，自引：0，他引：1       下载免费PDF全文

Dingwell RT  Leslie KE  Schukken YH  Sargeant JM  Timms LL 《The Canadian veterinary journal. La revue veterinaire canadienne》2003,44(5):413-416

The purpose of this study was to evaluate the usefulness of the California mastitis test (CMT) to detect an intramammary infection caused by a major mastitis pathogen in early lactation cows. The gold standard used for comparison was bacteriological culture of single milk samples. The sensitivity (82.4%) and specificity (80.6%) of a positive CMT were highest on the 4th day of lactation.  相似文献   

Mycobacterium paratuberculosis in dairy herds in Alberta          下载免费PDF全文

Sorensen O  Rawluk S  Wu J  Manninen K  Ollis G 《The Canadian veterinary journal. La revue veterinaire canadienne》2003,44(3):221-226

Fifty dairy herds in Alberta were tested for the presence of Mycobacterium paratuberculosis by fecal culture and serum enzyme linked immunosorbent assay (ELISA). Individual sera (1500) were tested for antibodies to M. paratuberculosis by ELISA. Fecal samples were combined in pools of 3 (10 pools/herd) for a total of 500 pools that were cultured for M. paratuberculosis. Thirty cultures, including all 10 pools from 1 herd, were not readable due to fungal contamination. The remaining 470 cultures, representing 49 herds, yielded 16 positive pools (3.4% +/- 2.1%) from 10 herds (20.4% +/- 11.3%). The ELISA of each of the 1500 sera detected 105 (7.0% +/- 2.4%) positive sera and 20 (40.0% +/- 13.6%) positive herds, based on 2 or more individual positive sera in the herd. The true herd-level prevalence, as determined by ELISA, was 26.8% +/- 9.6%. The true herd-level prevalence, as determined by M. paratuberculosis fecal culture, ranged from 27.6% +/- 6.5% to 57.1% +/- 8.3%, depending on whether 1, 2, or all 3 individual fecal samples in the positive fecal pool were culture positive.  相似文献   

Transjugular coil embolization of an intrahepatic portosystemic shunt in a cat     

Weisse C  Schwartz K  Stronger R  Mondschein JI  Solomon JA 《Journal of the American Veterinary Medical Association》2002,221(9):1287-91, 1266-7

A 4-month-old male domestic shorthair cat was evaluated for intermittent tremors, ptyalism, and signs of depression. The cat was small, thin, and unthrifty. Clinically important serum biochemical abnormalities included low blood urea nitrogen concentration and high baseline bile acids concentration. Abdominal ultrasonography and jejunal portography identified an intrahepatic portosystemic shunt. The cat was anesthetized, and a transjugular approach was used for percutaneous coil embolization of the shunt. Guidewires, catheters, and coils were inserted under fluoroscopic guidance to locate the shunt and define its anatomy, measure portal vein pressures before and after temporary balloon occlusion, and place thrombogenic coils to completely attenuate the anomalous vessel. The cat recovered without complications and was weaned from medical management. Ten weeks following the procedure, clinical signs had completely resolved, and baseline bile acids concentration was near reference range. Results in this cat illustrate that interventional radiology techniques can be safely used in small animals and may reduce the morbidity and mortality rates associated with traditional surgical procedures.  相似文献   

Comparison of insertion time and pullout strength between self-tapping and non-self-tapping AO 4.5-mm cortical bone screws in adult equine third metacarpal bone     

Andrea CR  Stover SM  Galuppo LD  Taylor KT  Rakestraw PC 《Veterinary surgery : VS》2002,31(3):189-194

OBJECTIVE: To compare screw insertion characteristics and pullout mechanical properties between self-tapping (ST) and non-self-tapping (NST) AO 4.5-mm cortical bone screws in adult equine third metacarpal bone (MC3). STUDY DESIGN: In vitro biomechanical experiment. ANIMALS OR SAMPLE POPULATION: Seven pairs of adult equine MC3. METHODS: Bicortical holes were drilled transversely in proximal metaphyseal, diaphyseal, and distal metaphyseal locations of paired MC3. NST screws were inserted in pre-tapped holes in 3 sites of one bone pair, and ST screws were inserted in non-tapped holes of contralateral MC3. Tapping and screw insertion times and maximum torques were measured. Screw pullout mechanical properties were determined. RESULTS: Screw insertion time was longer for ST screws. Total time for tapping and insertion (total insertion time) was over twice as long for NST screws. Statistically significant differences were not observed between screws for any pullout mechanical property. From pullout tests, diaphyseal locations had significantly stiffer and stronger structure than metaphyseal locations. Pullout failure more commonly occurred because of screw breakage than bone failure. Bone failure and bone comminution were more commonly associated with ST screws. Bone failure sites had pullout failure loads that were 90% of screw failure sites. CONCLUSIONS: NST and ST 4.5-mm-diameter cortical bone screws have similar pullout mechanical properties from adult equine MC3. ST screws require less than half the total insertion time of NST screws. CLINICAL RELEVANCE: Use of ST 4.5-mm-diameter cortical bone screws should be considered for repair of adult equine MC3 fractures; however, bone failures at screw sites should be monitored.  相似文献   

IgG antibody subclass response against equine herpesvirus type 4 in horses     

Mizukoshi F  Maeda K  Hamano M  Iwata H  Matsumura T  Kondo T  Sugiura T 《Veterinary immunology and immunopathology》2002,88(1-2):97-101

In this study, IgG subclass responses against equine herpesvirus type 4 (EHV-4) were examined by enzyme-linked immunosorbent assay (ELISA) using a type-specific region of EHV-4 glycoprotein G (gG). ELISA using sera collected from horses experimentally infected with EHV-4 revealed that IgGa and IgGb antibodies were detected at high level, but IgGc and IgG(T) antibody responses were detected at low level or were undetectable. The IgGa antibody response reached its peak on day 10 post-infection, and then dropped. The IgGb antibody response reached its maximum level on day 12 post-infection, and then the level was sustained during at least 28 days after infection. Forty healthy racehorses that had already been infected with EHV-4 possessed antibody against EHV-4. Although IgGa antibodies specific for EHV-4 were not detected in any horses, IgGb antibodies were detected and the levels correlated with total IgG antibodies against EHV-4 gG. The results suggest that EHV-4-specific IgGa and IgGb antibodies are induced in EHV-4-infected horses, and that IgGb antibody, but not IgGa, is long lasting.  相似文献   

The use of negative binomial modelling in a longitudinal study of gastrointestinal parasite burdens in Canadian dairy cows   总被引：3，自引：0，他引：3       下载免费PDF全文

Ane Ndtvedt  Ian Dohoo  Javier Sanchez  Gary Conboy  Luc DesCteaux  Greg Keefe  Ken Leslie    John Campbell 《Canadian journal of veterinary research》2002,66(4):249-257

The epidemiology of bovine gastrointestinal nematodes was investigated through a 1-year (October 1999 to September 2000) longitudinal study in 38 Canadian dairy herds from 4 different provinces (Prince Edward Island, Quebec, Ontario, Saskatchewan). For each herd, fecal egg counts from 8 randomly selected animals were performed on a monthly or quarterly basis. Larval cultures were performed once, to determine the species breakdown of the parasites. All producers were interviewed regarding herd management practices. The observed fecal egg counts were low in this study, with a range from 0 to 419 nematode eggs per 5 g of feces. The mean count was 9.8 and the median was 1. Standard transformations failed to normalize the data, which followed an over-dispersed Poisson distribution. A zero inflated negative binomial model was applied to assess factors that would influence the fecal egg counts. Identified associations were: egg counts were lowest in the winter and highest in the late spring; first-lactation cattle had higher counts than older cows; if manure was spread mechanically on pastures used by lactating cattle the egg counts were higher; and if manure was spread on heifer-pastures, the adult cows had lower counts. In herds where pasture use was more extensive, the cattle had higher fecal egg counts. The difference in pasture exposure was found to be a main contributor to an observed difference in fecal egg counts among herds in the 4 provinces.  相似文献