PubMed Health⌕ Search

Biomedical subjects

W A Ellis

Publications and source records attributed to W A Ellis.

At least 37 records · Page 2Linked to original sources
PubMed1996

Vitamin A deficiency enhances ozone-induced lung injury.

The present study determined the effects of vitamin A (vA) deficiency on the responses to ozone (O3) challenges in two inbred strains of mice that are differentially susceptible to O3-induced lung inflammation. Susceptible C57BL/6J (B6) and resistant C3H/HeJ (C3) dams at 2 wk gestation were fed test diets containing either 0 or 10 micrograms retinol/g diet. In mice that were maintained on vA-sufficient (vA+) diet, lung and liver tissue concentrations of vA and retinyl palmitate (RP) were significantly (P<0.05) lower in the B6 strain compared with C3, as measured by high-performance liquid chromatography techniques. vA and RP levels were significantly (P<0.05) reduced in lung and liver tissues of 8-wk old B6 and C3 mice that were maintained on a vA deficient (vA-) diet. vA+ and vA- mice of both strains were exposed to air or 0.3 ppm O3/72 h, and lung injury was assessed by differential cell count and total protein concentration in bronchoalveolar lavage (BAL) returns. O3 exposure caused significantly (P<0.05) greater increases in inflammatory cells and a total protein in BAL returns of vA+ B6 mice than vA+ C3 mice. vA deficiency significantly (P<0.05) enhanced O3-induced increases in polymorphonuclear leukocytes in C3 mice and epithelial cells loss in both strains. Compared with vA+ mice, lung permeability was also significantly (P<0.05) enhanced in vA- mice of both strains exposed to O3. vA replacement partially reversed the O3-induced lung injury that was enhanced by vA- diet. Results indicate that vA may have an important role in the pathogenesis of O3-induced lung injury in differentially susceptible inbred strains of mice.

Analysis of Variance↗
PubMed1995

Pathogenesis of porcine circovirus; experimental infections of colostrum deprived piglets and examination of pig foetal material.

The results of virus and antigen distribution following experimental infection of colostrum deprived pigs with pig circovirus (PCV) by oral/nasal and intravenous routes are reported. PCV and antigen were detected using virus isolation and indirect immunofluorescence on cryostat sections respectively. PCV antigen was detected in tissues throughout the body but primarily in spleen thymus, and lung. No PCV antigen or virus was detected in tissue samples from the central nervous system. Examination of pig foetal material from field cases of abortion/stillbirth resulted in 3 PCV isolates from 2 sera and a spleen sample from 2 groups of stillborn piglets from the same farm. No antibody to PCV alone was detected in 160 foetal sera tested. These results suggest that transplacental infection with PCV does occur, possibly prior to foetal immunocompetance. However, it is probably not a significant cause of reproductive disorders in pigs in Northern Ireland.

Animals↗
PubMed1995

Prevalence of Leptospira spp. in wild brown rats (Rattus norvegicus) on UK farms.

Wild brown rats (Rattus norvegicus) are frequently implicated in the carriage and spread of Leptospira spp. Wild brown rats (n = 259) were trapped from 11 UK farms and tested for Leptospira spp. using a number of diagnostic tests. The prevalence of leptospiral infection was low, but there was variation in the results obtained with the different diagnostic tests. Estimates of prevalence ranged between 0% by silver-staining of tissues, 1% by the microscopic agglutination test, 4% by the enzyme-linked immunosorbent assay, 4% by culture, and 8% by fluorescent antibody technique. In total, 37 (14%) rats were positive by at least one of the tests, which contrasts with the frequently reported prevalences of 50-70% for wild rats in the UK. Serovar bratislava was a prevalent as icterohaemorrhagiae, although it was present only on farms with larger rat populations.

Animals↗
PubMed1994

Leptospirosis as a cause of reproductive failure.

Leptospirosis is a zoonotic disease caused by members of the genus Leptospira. Veterinarians' perceptions of leptospirosis as a disease of domestic animals has undergone considerable modification in the past decade or so because they have increasingly appreciated the role of the host-maintained leptospires as causes of reproductive wastage in their respective host species kept under modern intensive management systems.

Abortion, Veterinary↗
PubMed1994

Characterization of Leptospira isolates from serovar hardjo by ribotyping, arbitrarily primed PCR, and mapped restriction site polymorphisms.

Leptospira serovar hardjo isolates of the hardjoprajitno and hardjobovis genotypes were characterized by ribotyping, arbitrarily primed PCR (AP-PCR) fingerprinting, and the study of mapped restriction site polymorphisms (MRSPs) in rrs and rrl genes. After restriction of chromosomal DNA with BglII, EcoRI, or HindIII, each genotype was individualized with a distinct ribotype. The fingerprints produced by AP-PCR with seven primers clearly separated the two groups; primers KF and RSP produced species-specific products which assigned hardjoprajitno and hardjobovis isolates to the species L. interrogans sensu stricto and L. borgpetersenii, respectively. Furthermore, AP-PCR fingerprints gave evidence of a considerable genomic heterogeneity at the strain level among the hardjobovis group. Conversely, the hardjoprajitno group was homogeneous. MRSP profiles in ribosomal genes indicated that hardjoprajitno and hardjobovis isolates belonged to L. interrogans MRSP group B and L. borgpetersenii group C, respectively. AP-PCR and determination of MRSPs in ribosomal genes proved to be quick and reliable methods for typing Leptospira strains and for studying intraspecific population structures.

Animals↗
PubMed1993

Immuno-dot blot as a rapid diagnostic method for detection of chlamydial infection in koalas (Phasolarctos cinereus).

The sensitivity and specificity of an immunoscreening test for anti-chlamydial antibodies in koala (Phasolarctos cinereus) serum were determined after the adsorption of non-specific antibodies. The results of the test were compared with complement fixation tests, tissue culture, gene probe analysis and dot blot immunoscreening for host-borne chlamydial antigen. The immunoscreening test was the most sensitive test for the identification of chlamydial infection in koala serum samples, furthermore it was rapid, taking approximately 16 hours to complete, and inexpensive. However, for the assay of swab material from koalas, gene probe analysis remains the most sensitive method of detection of chlamydiae.

Animals↗
PubMed1993

Association between cessation of leptospiruria in cattle and urinary antibody levels.

The shedding of Leptospira interrogans serovar hardjo in the urine of cattle and the local and systemic response to these organisms was monitored in experimentally and naturally infected animals. Twenty yearling heifers, 10 infected by the instillation of leptospires into the conjunctival sac (supraconjunctival route) and 10 infected intrauterinely, shed leptospires for up to 60 weeks after infection. Five of 15 naturally infected pregnant heifers with microscopic agglutination test titres > or = 1:300 continued to shed leptospires from 28 to 40 weeks after initial detection. Serovar hardjo was isolated infrequently from the urine of a further five naturally infected animals during the first eight weeks of the study but no leptospires were isolated from the remaining five animals for the duration of the study period (84 weeks). Cessation of leptospiruria in the 20 experimentally infected animals and in the five naturally infected persistent excretors was invariably associated with a sharp increase in urinary anti-leptospiral IgG and IgA antibody levels.

Animals↗
PubMed1993

Some aspects of the immune response of koalas (Phascolarctos cinereus) and in vitro neutralization of Chlamydia psittaci (koala strains).

Western-blot analysis was used to study the reaction of koala antisera, two specific polyclonal antibodies and one monoclonal antibody, with chlamydial antigens in koalas infected with Chlamydia psittaci. The koala sera recognized four C. psittaci surface antigens, corresponding to the major outer membrane protein (39.5 kDa), 31 kDa protein, 18 kDa protein and lipopolysaccharide. The S25-23 LPS specific monoclonal antibody inhibited chlamydial infection (55-67%) with both koala strains (type I and type II). Both koala antiserum and rabbit polyclonal antibodies against either type of chlamydia significantly reduced the number of infected cells resulting from type II infections at a dilution of 1 in 20. Rabbit antiserum against type II was effective in neutralizing infection by type II elementary bodies, but was less effective against type I infection. In addition, no koala antiserum was effective in neutralizing type I infection.

Animals↗
PubMed1993

Restriction fragment length polymorphisms distinguish Leptospira borgpetersenii serovar hardjo type hardjo-bovis isolates from different geographical locations.

Genetic variability among Leptospira borgpetersenii serovar hardjo type hardjo-bovis isolates representing several geographical regions was determined by restriction endonuclease analysis. Five previously unidentified EcoRI digestion patterns and one previously unidentified HhaI digestion pattern were seen with the various isolates. The copy number and genomic distribution of an L. borgpetersenii insertion sequence (IS1533) was determined. Hardjo-bovis isolate 033 (the type strain for hardjo-bovis) contained 40 well dispersed copies of IS1533. IS1533 probes were used to compare hardjo-bovis isolates by DNA blot hybridization analysis. Use of these probes showed the presence of additional genetic heterogeneity among hardjo-bovis isolates, which restriction endonuclease analysis did not show. Pulsed-field gel electrophoretic analysis of DNAs from several isolates suggested that some polymorphisms arose by genomic rearrangements. All hardjo-bovis isolates were categorized into 14 distinct groups on the basis of common hybridization and endonuclease digestion patterns. Most of these groups were isolated from distinct geographical regions, suggesting that several different clonal populations of hardjo-bovis exist.

Americas↗
PubMed1992

Duration of urinary excretion of leptospires by cattle naturally or experimentally infected with Leptospira interrogans serovar hardjo.

The excretion of Leptospira interrogans serovar hardjo in the urine of cattle was studied in naturally and experimentally infected animals. Five of 15 naturally infected animals with microscopic agglutination test titres of > or = 1:300 shed leptospires for between 28 and 40 weeks. Twenty yearling heifers, experimentally infected by either the supraconjunctival or intrauterine routes, shed leptospires for from eight to 60 weeks; the 10 infected via the uterus shed L interrogans serovar hardjo for a mean of 26 weeks (range eight to 54 weeks) and the 10 infected by the supraconjunctival route shed the organism for a mean of 32 weeks (range 12 to 60 weeks). The results suggest that natural infection results in more prolonged excretion than experimental infection. No intermittent or seasonal excretion of the organism was observed. After the initial experimental infection, large numbers of leptospires were shed in the urine for several weeks, and thereafter there was a progressive decline in the number of organisms shed.

Animals↗
PubMed1992

Stillbirth/perinatal weak calf syndrome: preliminary pathological, microbiological and biochemical findings.

Microbiological, biochemical and pathological data collected from 293 calves which were either stillborn, or born alive and either failed to breathe or failed to breathe for more than about 10 minutes are presented. No bacteria were recovered from 96 of the calves (32.7 per cent), and bacteria which were considered significant were isolated from only four (1.4 per cent). Evidence of leptospiral infection was found in 75 calves (25.5 per cent). Of 64 calves examined for bovine virus diarrhoea (BVD) and infectious bovine rhinotracheitis (IBR) antigens, two were positive for BVD virus and none for IBR virus. The mean (+/- sd) liver vitamin E and kidney selenium concentrations, determined in 148 of the calves, were 2.0 +/- 0.76 micrograms/g wet matter and 0.47 +/- 0.17 micrograms/g wet matter, respectively. The thyroid iodine concentration in 15 of 71 calves (21 per cent) was less than 300 micrograms/g wet matter and the mean (+/- sd) thyroid weight of 266 of the calves was 18.5 +/- 11.6 g. Evidence of severe trauma was found in 19 of the calves (6.5 per cent). Histological findings included thyroid epithelial hyperplasia, hepatic haemosiderosis, erythrophagocytosis in the spleen, perivascular haemorrhage in brain and adrenal glands, and accumulation of leucocytes in blood vessels.

Animals↗
PubMed1992

The isolation and identification of Leptospira interrogans serovar bratislava from a pig in Germany.

During a study on the improvement of selective media for the isolation of leptospires from clinical material, leptospires were isolated from the kidneys of a pig. Test material was cultured in EMJH-medium containing 0.4% rabbit serum and 3 inhibitory substances (Rifampicin 10 micrograms/ml, Amphotericin B 2 micrograms/ml, 5-Fluorouracil 100 micrograms/ml). The cultured leptospira-strain (Berlin 406) was identified to serogroup level using the cross agglutination method and it was further typed to serovar level by MAB's, factor analysis and restriction endonuclease analysis (REA). MAB typing of Berlin 406 gave an agglutination pattern profile typical of serovar bratislava. Factor serum identification clearly identified this strain as serovar bratislava. On REA examination, Berlin 406 gave a profile identical to that of the serovar bratislava type strain Jez Bratislava i.e. genotype B1. This is the first report of a confirmed isolate of Leptospira interrogans serovar bratislava from domestic animals in Germany. There exist a number of possibly important implications as this agent is being incriminated in the cause of clinical disease not only in pigs, but also in horses and dogs in other countries.

Animals↗