Pathogenicity of porcine enterotoxigenic Escherichia coli that do not express K88, K99, F41, or 987P adhesins.     

T A Casey  B Nagy  H W Moon 《American journal of veterinary research》1992,53(9):1488-1492

Three-week-old weaned and colostrum-deprived neonatal (less than 1 day old) pigs were inoculated to determine the pathogenicity of 2 enterotoxigenic Escherichia coli isolates that do not express K88, K99, F41, or 987P adhesins (strains 2134 and 2171). Strains 2134 and 2171 were isolated from pigs that had diarrhea after weaning attributable to enterotoxigenic E coli infection. We found that both strains of E coli adhered in the ileum and caused diarrhea in pigs of both age groups. In control experiments, adherent bacteria were not seen in the ileum of pigs less than 1 day old or 3 weeks old that were noninoculated or inoculated with a nonpathogenic strain of E coli. These control pigs did not develop diarrhea. Antisera raised against strains 2134 and 2171 and absorbed with the autologous strain, grown at 18 C, were used for bacterial-agglutination and colony-immunoblot assays. Both absorbed antisera reacted with strains 2134 and 2171, but not with strains that express K99, F41, or 987P adhesins. A cross-reaction was observed with 2 wild-type K88 strains, but not with a K12 strain that expresses K88 pili. Indirect immunofluorescence with these absorbed antisera revealed adherent bacteria in frozen sections of ileum from pigs infected with either strain. We concluded that these strains are pathogenic and express a common surface antigen that may be a novel adhesin in E coli strains that cause diarrhea in weaned pigs.  相似文献   

Estrogen and progesterone receptor status of mammary carcinomas and correlation with clinical outcome in dogs.   总被引：3，自引：0，他引：3  

E A Sartin  S Barnes  R P Kwapien  L G Wolfe 《American journal of veterinary research》1992,53(11):2196-2200

Estrogen and progesterone receptors (ER, PR) were measured in cytosol fractions from 18 primary canine mammary carcinomas by use of biochemical assays. One or both receptors were detected (> 10 fmol/mg of cytosol protein) in 11 tumors: 5 ER and PR; 2 ER only; 4 PR only. Mean cytoplasmic receptor concentrations (fmol/mg of cytosol protein) were 22.8 +/- 2.9 (SEM) for ER and 51.0 +/- 10.3 for PR in tumors containing ER and PR, 28.8 +/- 12.1 for ER in tumors containing only ER and 13.2 +/- 1.5 for PR in tumors containing only PR. Estrogen or progesterone receptors or both were identified in 6 of 9 tubular adenocarcinomas, 4 of 5 papillary adenocarcinomas, and 1 of 1 squamous cell carcinoma. These receptors were not identified in solid carcinomas (n = 2) or a single spindle cell carcinoma. Although the number of cases was limited, survival times of dogs tended to be longest in those with tumors containing ER alone or in combination with PR, intermediate in those with tumors containing only PR, and shortest in those with tumors without ER or PR. A correlation was not apparent between receptor status and age, presence of ovaries, tumor size, or histologic classification of the tumor. In the analysis of this series, the extent of surgery (mastectomy of the involved gland vs unilateral or bilateral mastectomy) did not appear to influence the outcome of the disease, and metastasis to regional lymph nodes did not appear to be a reliable prognostic indicator.  相似文献   

Infection of bovine fetuses at 120 days' gestation with virulent and avirulent strains of bluetongue virus serotype 11.     

A S Waldvogel  G A Anderson  D L Phillips  B I Osburn 《Comparative immunology, microbiology and infectious diseases》1992,15(1):53-63

Bluetongue virus infection in sheep and cattle during fetal development causes neuropathology. Two strains of bluetongue virus serotype 11 designated as UC-2 and UC-8 have different virulence patterns in newborn mice. These viruses have distinctly different electropherotype patterns on polyacrylamide gel electrophoresis indicating a genetic difference in these two viruses of the same serotype. Four bovine fetuses each were inoculated intramuscularly with either UC-2 or UC-8, and one fetus was inoculated with placebo. The inoculation was made intramuscularly through the uterine wall at 120 days' gestation, and the bovine fetuses were recovered by cesarean section 12 or 20 days after inoculation. Fetal blood was collected for virus isolation and serology. Virus was reisolated from brain, blood, lung and liver. Both strains, UC-2 and UC-8, cause severe lesions in the 120 day fetuses. The encephalomalacic lesions occurred earlier and were more severe in fetuses inoculated with UC-8 as compared to those inoculated with UC-2. The subtle differences observed in the fetuses inoculated with the two different strains suggest that there is a difference in pathogenic potential of the two viruses. These differences do not appear to be completely dependent upon the host species.  相似文献   

Narbon Vetch (Vicia narbonensis L.): A Potential Feed Legume Crop for Dry Areas in West Asia     

A. M. Abd El  Moneim 《Journal of Agronomy and Crop Science》1992,169(5):347-353

Provision of feed supplies for the rapidly growing livestock population is essential in West Asia. Shortages can be alleviated by growing forage crops in the existing fallow lands.
Narbon vetch (Vicia narbonensis L.) is a leguminous species with high yield potential, drought tolerance and cold resistance. It could be used for grain and straw production as source for animal feed in dry areas. It is good source of protein with seeds contain 28 % protein yielding 364 kg per hectare protein, whilst straw contains 9 % protein and yields a similar amounts of digestible protein per hectare.
Nine promising lines of Narbon vetch developed at ICARDA were tested at two sites over four years under rainfed conditions. Since climatic conditions were considered to be of considerable importance, each site in each year was treated as a separate environment to give eight environments with annual rainfall varied from 195 to 504 mm.
Narbon vetch possessed high seedling vigour with rapid winter growth and negligible cold damage. Grain yield varied form 0.47 to 1.90 t/ha, with a harvest index varying from 30 to 40 %. The data indicated that below 300 mm rainfall the grain yield varied from 0.47 t/ha when rain fall was 195 mm to 1.4 t/ha when rainfall was 245 mm. Most of the lines had wide adaptation to dry areas in terms of both grain yield and stability. Climate, except early spring rains had little effect on biological and grain yields.  相似文献   

Feline immunodeficiency virus neurotropism: evidence that astrocytes and microglia are the primary target cells.     

S W Dow  M J Dreitz  E A Hoover 《Veterinary immunology and immunopathology》1992,35(1-2):23-35

To investigate the neuropathogenesis of feline immunodeficiency virus (FIV) infection in vitro, we have utilized three populations of cultured feline neural cells (astrocytes, microglia, brain endothelium) to assess the relative susceptibility to FIV infection, ability to produce viral antigens, and effects of infection on cell survival. Astrocytes appeared to be the most susceptible to infection, followed by microglia, whereas brain endothelial cells were relatively resistant to infection. Astrocyte infection resulted in syncytium formation and cell death, while microglial cells remained persistently and productively infected, without obvious cytopathic effects. These results suggest that FIV entry into the central nervous system probably does not occur via infected endothelium and that both astrocytes and microglia are more likely target cells for the virus.  相似文献   

Intravenous catheterisation of foetus and mare in late pregnancy: management and respiratory, circulatory and metabolic effects.     

P M Taylor  M Silver  A L Fowden 《Equine veterinary journal》1992,24(5):391-396

The uterine and umbilical vessels of 12 pregnant ponies were catheterised to study foetal metabolism. The effects of this procedure on maternal and foetal cardiovascular, respiratory, metabolic and adrenocortical activity were monitored during and after surgery. Premedication with acepromazine-butorphanol-detomidine was followed by induction of anaesthesia with detomidine and ketamine and maintenance, using mechanical ventilation, with halothane in oxygen and nitrous oxide. Mean maternal arterial blood pressure was greater than 70 mmHg during anaesthesia and arterial oxygen tension remained over 100 mmHg. The foetuses were adequately oxygenated but were hypercapnic and lactic acidaemic. Most maternal and foetal blood gases and metabolites had returned to normal by 24 h, although foetal plasma lactate fell more slowly. The maternal adrenocortical discharge was less severe than reported previously and plasma cortisol had fallen to basal levels by 48 h after surgery. Foetal plasma cortisol remained low and did not change during or after surgery. Arterio-venous metabolite and gas tension differences across the uterine and umbilical circulations were slightly greater at operation than in the recovery period, suggesting that uteroplacental perfusion may have been impaired during surgery. Post-operative recovery of the mare and foetus was satisfactory and subsequent problems associated with the foetal catheters were not related to the anaesthesia or surgery.  相似文献   

Characterization of phosphate species in urban sewage sludges by high-resolution solid-state ³¹P NMR     

E. FROSSARD  P. TEKELY  J.Y. GRIMAL 《European Journal of Soil Science》1994,45(4):403-408

The mineral forms of phosphorus in three urban sewage sludges were characterized using high-resolution solid-state phosphorus-31 nuclear magnetic resonance (NMR) coupled to a sequential extraction. The sludges studied were an anaerobically-digested and heat-treated sludge (Paris-Achères), an activated sludge (Briare) and an anaerobically-digested sludge (Nancy). NMR observations were conducted using both single-pulse and cross-polarization sequences in order to distinguish between ³¹P nuclei far from ¹H nuclei, and ³¹P located within a fraction of a nanometre of ¹H. This approach showed that a complex mixture of P species was present in these sludges. A mixture of hydrogenated octocalcium phosphates and apatites was observed in the three samples. Monetite was present in the anaerobically-digested sludge and brushite in the activated sludge. Dehydrogenated condensed calcium phosphates (compounds with a Ca:P ratio higher than 1.0 such as fluorapatite or tricalcium phosphate) and dehydrogenated pyrophosphates were also probably present in the anaerobically-digested sludge. A poorly-ordered wavellite was observed in the three sludges after the HCl extraction. However, results were inconclusive as to whether this mineral was present in the three sludges, or had been precipitated during the sequential extraction.  相似文献   

Xylazine and tiletamine-zolazepam anesthesia in horses   总被引：4，自引：0，他引：4  

J A Hubbell  R M Bednarski  W W Muir 《American journal of veterinary research》1989,50(5):737-742

The cardiopulmonary and anesthetic effects of xylazine in combination with a 1:1 mixture of tiletamine and zolazepam were determined in 6 horses. Each horse was given xylazine IV or IM, as well as tiletamine-zolazepam IV on 4 randomized occasions. Anesthetics were administered at the rate of 1.1 mg of xylazine/kg of body weight, IV, 1.1 mg of tiletamine-zolazepam/kg, IV (treatment 1); 1.1 mg of xylazine/kg, IV, 1.65 mg of tiletamine-zolazepam/kg, IV (treatment 2); 1.1 mg of xylazine/kg, IV, 2.2 mg of tiletamine-zolazepam/kg, IV (treatment 3); and 2.2 mg of xylazine/kg, IM, 1.65 mg of tiletamine-zolazepam/kg, IV (treatment 4). Tiletamine-zolazepam doses were the sum of tiletamine plus zolazepam. Xylazine, when given IV, was given 5 minutes before tiletamine-zolazepam. Xylazine, when given IM, was given 10 minutes before tiletamine-zolazepam. Tiletamine-zolazepam induced recumbency in all horses. Duration of recumbency in group 1 was 31.9 +/- 7.2 (mean +/- 1 SD) minutes. Increasing the dosage of tiletamine-zolazepam (treatments 2 and 3) significantly (P less than 0.05) increased the duration of recumbency. Xylazine caused significant (P less than 0.05) decreases in heart rate and cardiac output and significant (P less than 0.05) increases in central venous pressure and mean pulmonary artery pressure 5 minutes after administration. Respiratory rate was decreased. Arterial blood pressures increased significantly (P less than 0.05) after xylazine was administered IV in treatments 1 and 3, but the increases were not significant in treatment 2. Xylazine administered IM caused significant (P less than 0.05) increases in central venous pressure and significant (P less than 0.05) decreases in cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Induced Maturation and Spawning of the Chinese Catfish Clarias fuscus     

Michael J. A.  Young Arlo W.  Fast Paul G.  Olin 《Journal of the World Aquaculture Society》1989,20(1):7-11

Chinese catfish ( Clarias fuscus ) were successfully spawned in Hawaii using human chorionic gonadotropin (HCG) at dosage rates of two and four international units (IU) per gram body weight. Fish not injected with HCG did not produce viable eggs. Successful spawns with HCG occurred between May and October. Hatch rates of up to 80% were obtained during June, July, and August for those fish given either a 2 or 4 IU per gram body weight injection of HCG. Fish spawned in either May or October yielded significantly higher hatch rates when injected with 4 rather than 2 IU per gram body weight. Fish held at elevated temperatures (28 to 30 C) prior to the normal spawning season developed significantly larger oocyte diameters, 60 days earlier than fish held under ambient temperature conditions (21.5 to 24 C). Photoperiod manipulation at ambient temperature conditions was associated with earlier oocyte maturation, but photoperiod effects were much less important than temperature.  相似文献   

Flowering events in relation to smut susceptibility in pearl millet   总被引：1，自引：0，他引：1  

R. P. THAKUR 《Plant pathology》1989,38(4):557-563

In field experiments at ICRISAT, selected lines of pearl millet (Pennisetum glaucum) resistant and susceptible to smut (Tolyposporium penicillariae) were evaluated for the timing of flowering events. In smut-resistant lines, the time from the boot-leaf stage (inoculation) to stigma emergence varied in the range 46–120 h, from boot to anther emergence 105–190 h, and from stigma emergence to anther emergence (protogyny period) 59–131 h; in smut-susceptible lines, the corresponding periods were 62–140 h, 146–200 h and 44–120 h, respectively. There were no significant correlations between timing of events and smut severity. Three cytoplasmically male-sterile lines showed longer protogyny periods and higher smut severity than their corresponding maintainer lines. Four lines having short protogyny periods (22–52 h) and resistance to ergot (Claviceps fusiformis) also showed high resistance to smut. Resistance to smut in most ergot-susceptible lines was independent of the timing of flow ering events, but in ergot-resistant lines it could be closely related to flowering events.  相似文献