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Biomedical subjects

W R Kelly

Publications and source records attributed to W R Kelly.

At least 19 recordsLinked to original sources

An apparent outbreak of cutaneous papillomatosis in merino sheep in patagonia, Argentina.

A retrospective study was performed on skin samples from an outbreak of cutaneous papillomatosis in Merino sheep that occurred in 1995. The samples were processed for routine histology, electron microscopy and immunocytochemistry for papilloma viruses. Particles of approximately 55 nm diameter were found in some nuclei of the stratum granulosum cells, while immunocytochemistry gave positive staining of cell nuclei in this layer. This study confirms that papillomas associated with papillomaviruses occur in sheep in Patagonia.

Animals↗

Antibody response in goats vaccinated with liposome-adjuvanted Clostridium perfringens type D epsilon toxoid.

A trial was performed using 20 goats to evaluate the antibody responses to a liposome-adjuvanted Clostridium perfringens epsilon toxoid vaccine (LIPV). The antibody response was compared with those produced by epsilon toxoid vaccines prepared using aluminium hydroxide (ALV) and incomplete Freud's adjuvant (FAV). The animals were allocated to four groups at the beginning of the trial. The animals in group 1 were vaccinated with ALV, while the animals in group 2 received FAV and those in groups 3 and 4 were vaccinated with LIPV. The animals in groups 1 to 3 received three doses of the corresponding vaccine at intervals of three weeks, while those in group 4 received only 1 dose of vaccine at the beginning of the trial. A blood sample was obtained from all the goats at the beginning of the trial and then weekly for 8 weeks. The samples were analysed for epsilon toxoid antibodies by an indirect ELISA technique. No major clinical abnormalities were observed in the animals after vaccination, with the exception of those that received the FAV, which experienced transient lameness. The highest antibody response was observed in the animals vaccinated with FAV, but they presented moderate to severe inflammatory tissue reactions at the injection site. Moderately high antibody responses were obtained with the ALV, with which only minor local reactions were observed. No significant antibody responses were obtained with the LIPV, nor were local reactions observed.

Aluminum Hydroxide↗

Resistance of ovine, caprine and bovine endothelial cells to Clostridium perfringens type D epsilon toxin in vitro.

Ovine, caprine and bovine endothelial cells were grown in vitro and challenged with Clostridium perfringens type D epsilon toxin to compare their susceptibility to this toxin. Madin Darby canine kidney (MDCK) cells, which are known to be susceptible to epsilon toxin, were used as a positive control. No morphological alterations were observed in any of the endothelial cell cultures tested, even after challenging with doses as high as 1200 MLD50/ml of epsilon toxin. MDCK cells showed contour rounding and nuclear condensation as early as 30 min after exposure to 100 MLD50/ml of epsilon toxin and after 60 min of exposure to 12.5 MLD50/ml of the same toxin. All the MDCK cells were dead after 3 h of exposure to all concentrations of epsilon toxin. The results indicate that ovine, caprine and bovine endothelial cells are not morphologically responsive to the action of epsilon toxin in vitro.

Animals↗

PCR detection of Clostridium perfringens type D in formalin-fixed, paraffin-embedded tissues of goats and sheep.

A polymerase chain reaction (PCR) was used to identify the genes encoding the alpha, epsilon and beta toxins of Clostridium perfringens in formalin-fixed, paraffin-embedded intestinal tissues of goats and sheep. When pure cultures of Cl. perfringens types B and D were used as control templates in the PCR, products of the following sizes were observed on the agarose gel: 247 bp (alpha primers), 1025 bp (beta primers) and 403 bp (epsilon primers). When used to identify Cl. perfringens type D in formalin-fixed, paraffin-embedded intestinal tissues of goats and sheep, the PCR technique resulted in the detection of this micro-organism in 11 out of 13 samples known to be infected with Cl. perfringens. No false positive results were obtained when 13 culturally negative samples were analysed by the PCR technique.

Animals↗

Comparison of the effects of Clostridium perfringens type D culture supernates in ligated intestinal loops of goats and sheep.

The effects of Clostridium perfringens type D culture supernates were compared in ligated loops of the small intestine (ileum) and colon of four goat kids and four lambs, the loops being examined histopathologically and electron microscopically 7 h after inoculation. No lesions were observed in the small intestine of any animal, or in control colonic loops. In the caprine and ovine colonic loops treated with culture supernates, most goblet cells were empty and the lumina contained a layer of mucus, polymorphonuclear leucocytes, bacteria and sloughed epithelial cells. The apical cytoplasm of the superficial epithelial cells was lost. Moderate oedema was observed in the submucosa and muscular layer. The colonic lesions were more severe in kids than in lambs. No changes were seen in vascular endothelial cells in any loop. 1999 W.B. Saunders and Company Ltd.

Animals↗

Variability of serum antibody responses of goat kids to a commercial Clostridium perfringens epsilon toxoid vaccine.

Twenty-nine Angora goats were used in a trial of a commercial enterotoxaemia (pulpy kidney disease) vaccine. The animals were allocated to four groups, of which three received an initial dose of vaccine, two also received a booster of the same vaccine either 28 or 42 days after the first vaccination, and the fourth remained as an unvaccinated control group. An indirect ELISA technique was used to measure the titres of Clostridium perfringens type D epsilon antitoxin in serum samples taken before vaccination and 17, 28, 42, 59, 70, 86, 98 and 128 days after vaccination. There was a wide range of antibody titres after vaccination, and the great majority of the vaccinated animals had titres below the protective level, arbitrarily set at 0.25 iu/ml, by day 98.

Animals↗

Protection of goats against experimental enterotoxaemia by vaccination with Clostridium perfringens type D epsilon toxoid.

Enterotoxaemia in goats is mainly characterized by enterocolitis, and it has been suggested that the poor efficacy of commercial vaccines in preventing the disease is due to the local action of Clostridium perfringens toxin/s within the intestine, where circulating antibodies might not exert their action. Five goat kids were vaccinated with an incomplete Freund's adjuvant C perfringens type D epsilon toxoid vaccine on three occasions at three-week intervals, four similar kids were vaccinated with a commercial enterotoxaemia vaccine at the same times, and five other unvaccinated kids were used as controls. All the animals were challenged intraduodenally, one week after the last vaccination, with C perfringens type D filtered culture supernatant. At the time of challenge, the level of epsilon toxin antibodies in the serum of the Freund's adjuvant-vaccinated kids ranged between 2.45 and 230 iu/ml, while the kids that received the commercial vaccine had levels between 0.22 and 1.52 iu/ml. No clinical or postmortem changes were observed in the kids that received the Freund's adjuvant-vaccine. Three of the four kids that received the commercial vaccine developed mild, pasty diarrhoea, with a slight reddening of the colonic mucosa being observed postmortem. All the unvaccinated kids developed severe diarrhoea, respiratory distress and central nervous system signs, and were killed humanely between six and 24 hours after challenge. The postmortem changes consisted of pseudomembranous colitis, lung oedema and perivascular oedema of the brain. Moderate to high serum levels of anti-epsilon antibody appeared to protect the goats against both the systemic and the intestinal effects of C perfringens type D toxins.

Animals↗

Lesions caused by cardiovascular flukes (Digenea: Spirorchidae) in stranded green turtles (Chelonia mydas).

Evidence of infection with spirorchid flukes (Digenea: Spirorchidae) was sought at necropsy of 96 stranded green turtles, Chelonia mydas, that were examined during the course of a survey of marine turtle mortality in southeastern Queensland, Australia. Three species of spirorchid (Hapalotrema mehrai, H. postorchis, and Neospirorchis schistosomatoides) were identified. Severe disease due to spirorchid fluke infection (spirorchidiasis) was implicated as the principal cause of mortality in 10 turtles (10%), and appeared to be one of multiple severe problems in an additional 29 turtles (30%). Although flukes were observed in only 45% of stranded C. mydas in this study, presumed spirorchid fluke infection was diagnosed in an additional 53% of turtles, based principally on characteristic necropsy lesions and to a lesser extent on the histopathological detection of spirorchid eggs. Characteristic necropsy lesions included miliary spirorchid egg granulomas, which were observed most readily on serosal surfaces, particularly of the small intestine. Cardiovascular lesions included mural endocarditis, arteritis, and thrombosis, frequently accompanied by aneurysm formation. Resolution of thrombi was observed to occur via a combination of granuloma formation about indigestible components (spirorchid fluke egg shells) and exteriorization through the vessel wall, which resulted in granulomatous nodules on the adventitial surface. Septic aortic thrombosis complicated by disseminated bacterial infection, observed in five turtles, was recorded for the first time. Egg granulomas were ubiquitous in turtle tissues throughout this study. Although they generally appeared to be mild or incidental lesions, they were occasionally associated with severe multifocal granulomatous pneumonia or meningitis.

Animals↗

Experimental Clostridium perfringens type D enterotoxemia in goats.

The effects of intraduodenal administration of Clostridium perfringens cultures and culture products in goats were evaluated to develop a reliable experimental model of enterotoxemia in this species. Five conventionally reared, 11-16-week-old Angora goat kids were dosed intraduodenally with whole cultures of C. perfringens type D; five similar animals were dosed with C. perfringens type D filtered culture supernatant; and a third group of five kids was dosed with C. perfringens type D washed cells. Two kids were used as controls and received sterile, nontoxic culture medium intraduodenally. All animals received starch solution into the abomasum. All five kids inoculated with whole culture and three of five dosed with culture supernatant and with washed cells developed central nervous system signs. Diarrhea was observed in two of five kids inoculated with whole culture, in all five of those dosed with culture supernatant, and in three of five of those that received washed cells. The most striking postmortem findings consisted of lung edema, necrotizing pseudomembranous colitis, and cerebral vasogenic edema. The protocol thus provided a reasonable model of naturally occurring enterotoxemia in goats, producing a range of clinical signs and postmortem changes similar to those observed in the natural disease.

Abomasum↗

Caprine enterotoxaemia associated with cerebral microangiopathy.

Cerebral microangiopathy is described in naturally occurring clostridial enterotoxaemia in two goats. The two cases were selected from the files of two diagnostic laboratories in Australia, on the basis that the clinical syndrome and history were consistent with a diagnosis of enterotoxaemia, and that the diagnosis was confirmed by the identification of epsilon toxin in the intestinal contents. The lesions consisted of acute perivascular proteinaceous exudate in the brain and bilaterally symmetrical foci of encephalomalacia were observed in one of the goats. These brain lesions confirm that Clostridium perfringens type D enterotoxaemia may produce histologically detectable brain changes in goats.

Animals↗

Effects of the intravenous administration of Clostridium perfringens type D epsilon toxin on young goats and lambs.

Young goats (n = 18) and lambs (n = 10) were compared in respect of the effects of Clostridium perfringens type D epsilon toxin. Toxin produced neurological signs within 0.5-3 h of intravenous injection in (1) all of six kids given doses of 250, 185 or 120 mouse lethal doses 50% (MLD50)/kg body weight, (2) two of the three kids given 60 MLD50/kg, and (3) all of five lambs given 250 or 120 MLD50/kg. Six kids and three lambs given 45, 30 or 15 MLD50/kg, one lamb given 60 MLD50/kg, and three kids and one lamb given saline (controls) all remained clinically normal. Gross post-mortem changes were observed only in the kids and lambs that showed clinical signs. In the kids these changes consisted of severe acute interstitial and alveolar oedema of the lungs. However, only two out of five lambs that presented clinical signs showed pulmonary oedema. No histological changes were observed in the brain of any of the kids inoculated with epsilon toxin. In the brain of four out of the five lambs given doses of 120 or 250 MLD50/kg, there were histological lesions consisting of perivascular proteinaceous oedema and haemorrhages. These results show that kids and lambs are equally susceptible to the intravenous injection of epsilon toxin, but that they differ in the histological response of the central nervous system to the toxin.

Animals↗

Detection of Clostridium perfringens type D epsilon antitoxin in serum of goats by competitive and indirect ELISA.

Indirect and competitive ELISA techniques were developed and their ability to detect antibodies to Clostridium perfringens epsilon toxin in goat serum was compared. Different dilutions of a hyperimmune goat serum, in serum from a colostrum-deprived kid, were used as positive controls, while sera from eleven colostrum-deprived kids were used as negative controls. The epsilon toxin antibodies in the hyperimmune serum were also measured by mouse neutralisation test (MNT). The correlation coefficient between both the indirect ELISA technique and MNT was 0.99, while the same coefficient for the competitive ELISA was 0.98. Both the indirect and competitive ELISAs proved to be rapid, simple, sensitive and specific for detecting antibodies to C. perfringens epsilon toxin in serum of goats.

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PCR detection of Clostridium perfringens producing different toxins in faeces of goats.

A polymerase chain reaction (PCR) was used to identify the genes encoding the major toxins of Clostridium perfringens in faeces of goats. When pure cultures of Cl. perfringens types A, B, C, D and E were used as templates in the PCR, amplicons were observed on the agarose gel as bands at approximately the 247 (alpha primers), 1025 (beta primers), 403 (epsilon primers) and 298 (iota primers) bp level of the DNA marker. When used to identify different types of Cl. perfringens in samples artificially spiked with these micro-organisms, the PCR detected as few as 1-1.5 x 10(2) cfu g-1 of the five types of Cl. perfringens tested. The PCR technique allowed the identification and typing of Cl. perfringens strains in faeces of goats, without recourse to other techniques such as the mouse neutralization test.

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Form and function of lacunae in the ovary of the laying hen.

BACKGROUND: Spontaneous atresia of large, yolky, ovarian follicles occurs in the chicken and in other species when the stimulus for ovulation ceases. This means that as much as 40 ml of yolk must be resorbed by the ovary if normal ovarian morphology is to be regained. This study examines the process of yolk resorption in the ovarian stroma following bursting atresia. METHOD: Light, transmission, and scanning electron microscopy were used to study the morphology of lacuna spaces and their changes in ovaries of broiler and layer breeds of domestic chicken, both in actively laying birds and in birds undergoing spontaneous or induced follicular atresia. A comparative study was made of the ultrastructural differences between lacuna-lining cells, blood-vessel endothelium, and germinal epithelium of the ovary. RESULTS: Transformation of lacuna-lining cells and peritoneal cells into macrophages occurred after bursting atresia and exposure of these cells to released yolk. Complete atresia of large yolky follicles occurred very quickly. CONCLUSION: The resorption of this large volume of yolk, at least in part, seems to be mediated by the transformed lacuna-lining cells.

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