Quantitative and qualitative properties of host polymorphonuclear cells during experimentally induced Staphylococcus aureus mastitis in cows     

M J Daley  E R Oldham  T J Williams  P A Coyle 《American journal of veterinary research》1991,52(3):474-479

Polymorphonuclear cells have a critical role in the pathogenesis of bovine mastitis. We have documented that experimentally induced Staphylococcus aureus mastitis is associated with cyclic increase and decrease in the quantity of viable bacteria shed in the milk. Concomitant with this cycling of bacteria is an inverse cycling of the hosts cells within the milk. Such somatic cells were determined to be greater than or equal to 95% polymorphonuclear cells. The quality of these cells was evaluated by measuring their relative efficiency of bacterial killing and phagocytosis at various times during an infection. Host polymorphonuclear cells had as much as 10,000-fold variation in the bactericidal failure rate for staphylococci during cell cycling. The most efficient bactericidal effect was observed at or near the peak of the somatic cell count (SCC). The ability of these cycling cells to ingest fluorescent beads was also quantitated by use of flow cytometry. The percentage of phagocytic polymorphonuclear cells that ingested fluorescent latex beads ranged from 15 to 80% of the total cell population during cell cycling, and tended to be optimal at or near peak SCC. In addition, the average number of beads ingested varied between 1 and 2 particles/polymorphonuclear cell, with as many as 17% of the phagocytic cells ingesting 4 or more beads at maximal efficiency. Polymorphonuclear cells from quarters infected with S aureus varied quantitatively (total SCC) and qualitatively (bactericidal activity and phagocytic ability) during the course of an infection. Not only is the quantity of host's phagocytic cells in the mammary gland central to the defense mechanism against infection, but the biological activation state appears to be equally important. The role of these cells in the pathogenesis of a cycling infection is presented in a model to explain the cyclic nature of mastitis.  相似文献   

Neuronal necrosis in budgerigars treated with dimetridazole   总被引：1，自引：0，他引：1  

MJ LANCASTER  LN HOOPER 《Australian veterinary journal》1991,68(8):280-281

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Analysis of bile crystals from sheep grazing Panicum schinzii (sweet grass)     

MJ LANCASTER  I. VIT  RL LYFORD 《Australian veterinary journal》1991,68(8):281-281

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Observations on production of hemolysin, heat-labile enterotoxin and antimicrobial drug resistance among enterotoxigenic Escherichia coli from pigs.     

H. Hariharan  S. Heaney  J. Bryenton  J. Daley 《Comparative immunology, microbiology and infectious diseases》1992,15(4):229-234

A total of 52 isolates of Escherichia coli belonging to enterotoxigenic serotypes from piglets with diarrhea were examined for hemolysis, production of cholera-like enterotoxin (LT) and susceptibility to 10 antimicrobial drugs. A strong association between production of LT and hemolysis was seen. Ninety percent of 29 hemolylic isolates were LT⁺ whereas 100% of 23 nonhemolytic isolates were LT⁻ in a commercial latex agglutination assay. Antimicrobial susceptibility tests employing disc diffusion showed that resistance to trimethoprim-sulfamethoxazole (TMS), neomycin and tetracycline was significantly less among LT⁺ isolates compared to LT⁻ ones. Enrofloxacin was the only antimicrobial drug to which all the 52 isolates were susceptible.  相似文献   

The CML-specific P210 bcr/abl protein, unlike v-abl, does not transform NIH/3T3 fibroblasts   总被引：32，自引：0，他引：32  

G Q Daley  J McLaughlin  O N Witte  D Baltimore 《Science (New York, N.Y.)》1987,237(4814):532-535

The v-abl oncogene of the Abelson murine leukemia virus (A-MuLV) is known to efficiently transform NIH/3T3 fibroblasts in vitro and to cause an acute lymphosarcoma in susceptible murine hosts. The role of its relative, the bcr/abl gene product, in the etiology of human chronic myelogenous leukemia (CML) remains speculative. To assess the transforming properties of the bcr/abl gene product, complementary DNA clones encoding the CML-specific P210 bcr/abl protein were expressed in NIH/3T3 fibroblasts. In contrast to the v-abl oncogene product P160, the P210 bcr/abl gene product did not transform NIH/3T3 cells. Cell lines were isolated that expressed high levels of the P210 bcr/abl protein but were morphologically normal. During the course of these experiments, a transforming recombinant of bcr/abl was isolated which fuses gag determinants derived from helper virus to the NH2-terminus of the bcr/abl protein. This suggests that a property of viral gag sequences, probably myristylation-dependent membrane localization, must be provided to bcr/abl for it to transform fibroblasts.  相似文献   

Comparison of efficacy of sulbactam: ampicillin to ampicillin and saline for treatment of experimentally induced Escherichia coli diarrhea in neonatal calves.          下载免费PDF全文

J Lofstedt  L Miller  G Duizer    J Daley 《Canadian journal of veterinary research》1996,60(3):210-215

A study was conducted to compare the efficacy of sulbactam: ampicillin (SAMP) (3.3:6.6 mg/kg body weight (BW), IM, q24 h) to that of ampicillin trihydrate (AMP) (6 mg/kg BW, IM, q24 h) and 0.9% saline (SAL) (3 mL IM, q24 h) for the treatment of diarrhea in calves induced by oral inoculation with Escherichia coli strain B44 (O9:K30:K99:H-). Treatment was initiated when severe diarrhea was noted (T0) and continued for at least 3 d; or for 24 h after clinical signs resolved; or for a maximum duration of 7 d. Starting at T0, calves were examined twice daily: appetite; rectal temperature (TEMP); and fecal consistency (FECAL), mental status (ATTD), eye position (EYE), and skin elasticity (SKIN) scores were recorded. Feces collected at T0 were submitted for bacteriology, electron microscopy, and parasitology. A complete blood count was performed at T0 and T3 (24 h after third treatment). Severely dehydrated, depressed, and anorexic calves were euthanized and considered mortalities. Cause of death was determined by post mortem examination. A total of 30 calves were included in the study. Three calves were excluded from final analysis. E. coli strain B44 was cultured from feces of all calves at T0. At T2 (24 h after second treatment) mean TEMP of SAMP calves was significantly higher (P < 0.05) than mean TEMP of SAL calves; EYE and SKIN scores of SAMP calves were significantly lower (P < alpha beta = 0.025) than those of SAL and AMP calves; and ATTD and FECAL scores of SAMP calves were significantly lower (P < alpha beta = 0.025) than in SAL calves. At T3, SAMP calves had significantly lower (P < 0.05) mean hematocrit than SAL calves and lower mean total plasma protein concentration than AMP and SAL calves. Mean fibrinogen concentration in SAMP calves at T3 was significantly lower (P < 0.05) than that of calves receiving either SAL or AMP. The number of surviving SAMP calves (10/10) was significantly higher (P < alpha beta = 0.025) than the number of surviving SAL calves (2/9), but not significantly different from the surviving AMP calves (3/8).  相似文献   

Echinococcus granulosus infection of foxes in south-eastern New South Wales     

DL OBENDORF  MJ MATHESON  RCA THOMPSON 《Australian veterinary journal》1989,66(4):123-124

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Leptospira interrogans serovar hardjo is not a major cause of bovine abortion in Victoria     

RJ. CHAPPEL  BD. MILLAR  B. ADLER †  J. HILL ‡  MJ. JEFFERS  RT. JONES  CJ. McCAUGHAN  LJ. MEAD  NW. SKILBECK 《Australian veterinary journal》1989,66(10):330-333

The aim of this study was to determine whether evidence could be obtained of foetal infection with Leptospira interrogans serovar hardjo in aborted foetuses collected from dairy farms. Material from 197 abortions occurring over a wide area of Victoria was collected over 3 years. None of 195 foetal kidney cultures or 7 cultures from membranes was positive for leptospiral organisms. Immunogold silver staining for leptospires was performed on sections of kidneys, lungs or heart from 156 foetuses, with negative results. Evidence of transient leptospiral infection in 11 of 123 foetuses was obtained by foetal heart blood serology. Two isolates of L. interrogans serovar hardjo were obtained from the urine of milking cows. These strains were examined by restriction endonuclease analysis and both were shown to be of the genotype Hardjobovis, as have been all Australian isolates studied so far. It appears that foetal infection with serovar hardjo is not associated with any substantial proportion of bovine abortions in Victoria, in contrast to the situation in Northern Ireland. The apparent absence from Victoria of the pathogenic genotype Hardjoprajitno is a possible explanation.  相似文献   

Patterns of Follicular Growth in Superovulated Sheep and Influence on Endocrine and Ovarian Response     

A Gonzalez-Bulnes  RM Garcia-Garcia  CJH Souza  J Santiago-Moreno  A Lopez-Sebastian  MJ Cocero  DT Baird 《Reproduction in domestic animals》2002,37(6):357-361

Objectives of this study were to characterize patterns of follicular development in sheep superovulated with purified follicle stimulating hormone (FSH) (OVAGEN^TM, ICP, Auckland, New Zealand) and to determine its influence on preovulatory events (onset of the oestrus behaviour and timing of the preovulatory luteinizing hormone surge) and ovarian response (ovulation rate and embryo yield). Number and size of all ≥ 23 mm follicles from the first FSH injection to withdrawal of progestagen sponges was determined by transrectal ultrasonography just prior to every FSH injection in nine Manchega ewes superovulated with eight decreasing doses (ml) (1.5 × 3, 1.25 × 2 and 1 × 3) of OVAGEN injected twice daily from 60 h before to 24 h after the withdrawal of 40 mg fluorogestone acetate sponges. Oestrous detection and jugular blood sampling for LH radioimmunoassay were performed every 3 h from 14 to 53 h after sponge removal and ovulation rate and number of embryos were determined 4 days after progestagen withdrawal. Administration of OVAGEN induced a significant rise (p < 0.0005) in the number of follicles ≥ 4 mm in size because of an increased growth in size of follicles from the first FSH injection to sponge removal, an increase in the number of newly detected follicles from 12 to 36 h of the first FSH dose (p < 0.005) and a decrease in regression rate from 24 h (p < 0.001). The number of follicles 2–3 mm in size at first FSH dose (10.4 ± 1.5) was positively correlated with the number of ≥ 4 mm follicles at 0 h (19.0 ± 2.7, p < 0.01). A higher number of ≥ 4 mm follicles at 0 h was related with an earlier appearance of oestrus (31.5 ± 1.5 h, p = 0.08) and LH surge (45.0 ± 2.3 h, p < 0.005), and a higher ovulation rate (18.2 ± 3.8, p < 0.005). On the other hand, the rate of embryo recovery was decreased in ewes with earlier preovulatory LH peaks (p < 0.005), with a shorter interval between oestrus and LH peak (p < 0.05).  相似文献   

Specificity of two absorbed ELISAs for surveys of Mycobacterium paratuberculosis in cattle     

TM ELLIS  BA CARSON  MJ KALKHOVEN  PAJ MARTIN 《Australian veterinary journal》1998,76(7):497-499

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