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Biomedical subjects

I D Robertson

Publications and source records attributed to I D Robertson.

At least 37 records · Page 2Linked to original sources
PubMed2002

The effects of polyester (terylene) fibre implants on normal equine superficial digital flexor tendon.

AIM: To determine the effect of polyester (terylene) fibre implants on normal equine superficial digital flexor (SDF) tendon structure. METHODS: Normal forelimb SDF tendons (n=24) of 12 horses were divided into unoperated, sham-operated, and implanted (terylene fibre implant) groups. Horses were assessed for lameness and ultrasonographic changes to SDF tendons at intervals up to 48 weeks post-operatively. After euthanasia, SDF tendons were collected for histological and ultrastructural examination. Histological sections were examined for alcian blue staining intensity, cellularity, fibril bundle alignment, fascicle separation and crimp morphology. Mass-average diameters (MADs) of collagen fibrils were calculated from electron micrographs and compared between treatment groups. RESULTS: Insertion of terylene fibre implants resulted in short-term (8 weeks) lameness in implanted limbs. Ultrasonographically, the implants could be detected in 50% of implanted tendons, but were associated with tendon swelling and the presence of hypoechoic core lesions in 7/8 implanted limbs. There were significant alterations in alcian blue staining, cellularity and crimp morphology in the central fascicles of sham-operated and implanted tendons, and alteration in fibril alignment in the central fascicles of implanted tendons. Unoperated tendons remained histologically normal. MADs of collagen fibrils did not differ between sham-operated, implanted and unoperated limbs. CONCLUSIONS: Both the sham procedure and the insertion of terylene fibre implants led to alterations in tendon structure that persisted for up to 48 weeks. Persistence of disorganised connective tissue at the proximal and distal ends of the terylene fibre implants may predispose implanted tendons to continued risk of injury. CLINICAL RELEVANCE: It is unlikely that terylene fibre implants offer any advantage over standard non-surgical treatments for mild to moderate cases of SDF tendonitis in the horse.

Journal Article↗
PubMed2000

Response of Bali cattle (Bos javanicus) to vaccination with Brucella abortus strain 19 in West Timor.

A trial was conducted in two villages (one containing cattle infected with brucellosis and one not containing infected cattle) in Timor, Indonesia to determine the serological response to vaccination with Brucella abortus strain 19 in Bali cattle (Bos javanicus) (n = 599). Mature female cattle were immunised with low-dose strain 19 (2x10(8)-6x10(8) colony forming units) and calves (6-12 months) with high-dose strain 19 (4x10(10)-12x10(10) colony forming units). Other mature females and calves were inoculated with sterile vaccine diluent and formed a non-vaccinated in-contact control group. The seroprevalence and mean titres were highest in the vaccinated cattle 3 months after vaccination. These then receded, however, 1% of vaccinated calves and 1.9% of vaccinated cows from the village without infected cattle were still seropositive on the complement-fixation test (CFT) 24 months after vaccination. Non-vaccinated seropositive animals were more likely to have aborted or had a stillbirth and were less likely to have produced a calf than were seronegative cows from the village containing infected animals. We concluded that strain 19 vaccine induced protection in Bali cattle and that this vaccine might play an important role in the control of bovine brucellosis in Timor.

Abortion, Veterinary↗
PubMed2000

Influences of diet and vaccination on colonisation of pigs by the intestinal spirochaete Brachyspira (Serpulina) pilosicoli.

The purpose of this study was to determine whether methods used to control swine dysentery (SD), caused by the intestinal spirochaete Brachyspira (Serpulina) hyodysenteriae, would also be effective in controlling porcine intestinal spirochaetosis (PIS) caused by the related spirochaete Brachyspira (Serpulina) pilosicoli. Weaner pigs in Groups I (n=8) and II (n=6) received a standard weaner pig diet based on wheat and lupins, whilst Group III (n=6) received an experimental diet based on cooked white rice and animal protein. Pigs in Group II were vaccinated intramuscularly twice at a 3-week-interval with a formalinised bacterin made from B. pilosicoli porcine strain 95/1000 resuspended in Freund's incomplete adjuvant. Eleven days later pigs in all groups were infected orally with 10(10) cells of strain 95/1000 on three successive days. One control pig in Group I developed acute diarrhoea, and at post-mortem had a severe erosive colitis with end-on attachment of spirochaetes to the colonic epithelium. All other pigs developed transient mild diarrhoea and had moderate patchy colitis at post-mortem 3 weeks later. B. pilosicoli was isolated from the faeces of all pigs, except for one fed rice, and was isolated from the mesenteric nodes of three pigs from Group I and from one vaccinated pig in Group II. Consumption of the rice-based diet, but not vaccination, delayed and significantly (p<0.001) reduced the onset of faecal excretion of B. pilosicoli after experimental challenge. Vaccination induced a primary and secondary serological response to B. pilosicoli, as measured using sonicated whole cells of strain 95/1000 as an ELISA plate coating antigen. Antibody titres in the vaccinated pigs then declined, despite intestinal colonisation by B. pilosicoli. Both groups of unvaccinated animals also failed to develop a post-infection increase in circulating antibody titres.

Animal Feed↗
PubMed2000

The role of companion animals in the emergence of parasitic zoonoses.

Pets offer individuals and the community significant benefits, however cognisance must be taken of the potential for transmission of infectious agents from these animals to humans. The prevalence of many parasites, such as Giardia and Cryptosporidium, has increased over the past few decades while others, such as Toxocara and Ancylostoma, have decreased. These changes could be real, associated with the ready availability of efficacious anthelmintic products or could be artificial due to the type of surveys conducted, the animals surveyed and the diagnostic tests used. Immunocompromised people, in particular, must be aware of the potential risk of acquiring parasitic infections from their pets. However, with the adoption of good hygiene and a thorough knowledge of the transmission of these parasites, immunocompromised people should be able to continue to enjoy the significant benefits of pet ownership. As many owners are not aware of the zoonotic parasites that could be carried by their pets or their mode of transmission, it is concluded that veterinarians need to play a greater role in the education of their clients.

Animals↗
PubMed2000

Pros and cons of barium-impregnated polyethylene spheres in gastrointestinal disease.

Barium-impregnated polyethylene spheres are an alternative contrast agent for radiographic studies of the gastrointestinal tract. The spheres are a practical, efficient, and relatively inexpensive way to diagnose a number of relatively common gastrointestinal conditions. They are most useful in the diagnosis of chronic conditions. Radiographic interpretation relies on a thorough understanding of the pathophysiology of gastrointestinal disease and how various disease states influence gastrointestinal function.

Animals↗
PubMed1999

Factors associated with prognosis for survival and athletic use in foals with septic arthritis: 93 cases (1987-1994).

OBJECTIVE: To identify factors affecting the prognosis for survival and athletic use in foals with septic arthritis. DESIGN: Retrospective study. ANIMALS: 93 foals with septic arthritis. PROCEDURE: Medical records were reviewed to obtain clinical findings, laboratory test results, radiographic findings, treatment method, and outcome. Race records for Thoroughbreds and Standardbreds were evaluated to determine whether foals subsequently raced and whether they raced successfully. RESULTS: 43 foals had 1 affected joint, 44 foals had multiple affected joints, and number of affected joints was not recorded for 6 foals. The femoropatellar and tarsocrural joints were most commonly affected. Osteomyelitis or degenerative joint disease were detected in 59% (46/78) of foals. Failure of passive transfer, pneumonia, and enteritis were common. Foals were treated with lavage, lavage and intra-articular administration of antibiotics, lavage and arthroscopic debridement with or without partial synovectomy, or lavage and arthrotomy to debride infected bone and systemic administration of antibiotics. Seventy-three foals survived to be discharged from hospital, and approximately a third raced. Isolation of Salmonella spp from synovial fluid was associated with an unfavorable prognosis for survival and multisystem disease was associated with an unfavorable prognosis for survival and ability to race; other variables were not significantly associated with survival and ability to race. CONCLUSIONS AND CLINICAL RELEVANCE: With treatment, the prognosis for survival of foals with septic arthritis was favorable, whereas prognosis for ability to race was unfavorable. Multisystem disease, isolation of Salmonella spp from synovial fluid, involvement of multiple joints, and synovial fluid neutrophil count > or = 95% at admission may be of prognostic value.

Animals↗
PubMed1999

The influence of diet and other factors on owner-perceived obesity in privately owned cats from metropolitan Perth, Western Australia.

A randomly selected group of cat-owning households (n = 458) were interviewed to determine the diet of their cats (n = 644) in the week prior to the survey and to identify dietary and other factors which were associated with obesity. All cats were categorised by their owners as underweight, correct-weight or overweight and the weight of 127 cats was also recorded. Nearly all cats were fed commercially prepared dry pet food (90.5%) or canned pet food (84.6%) in the week prior to the survey. Nineteen percent of cats were classified as overweight. Although the make-up of a cat's diet was found not to be associated with its weight or weight category, cats fed dietary supplements or those which had not received a specific kitten diet when <6 months of age were more likely to be overweight after univariable analysis. Logistic multiple regression was used to investigate the effect of putative risk factors on obesity while controlling for other factors. Overweight cats were more likely to be cross-bred (OR = 2.1), neutered (OR = 2.8), living in houses with only one or two cats (OR = 1.8), male (OR = 1.4) and predominantly confined inside a house (OR = 1.4). Obesity is influenced by a variety of factors including host, dietary and management factors and these must be considered when developing weight control programmes for cats.

Animal Feed↗
PubMed1999

Gastrointestinal parasites of urban dogs in Perth, Western Australia.

A study was conducted to determine the prevalence of gastrointestinal parasites in a sample of urban dogs in Perth and the knowledge of their owners about the control and zoonotic transmission of these parasites. Faecal samples (421), collected from dogs originating from five sources, were examined by microscopy and questionnaires administered to dog owners and managers/owners of pet shops. The prevalence of gastrointestinal parasitism was higher in pet shop puppies (51%), than in dogs from refuges (37%), breeding kennels (32.7%), veterinary clinics (15.6%) and exercise areas (5.3%). Protozoa, in particular Giardia, were detected more frequently (22.1%) than helminth parasites. After adjusting for other factors with multiple logistic regression, puppies less than 6 months of age, dogs living in households with more than one dog, and dogs from refuges were significantly more likely to be parasitized. The prevalence of Giardia was found to be directly associated with the number of doses of anthelmintics given in a year, increasing 1.2 times for each dose administered. The majority of owners were aware of the potential risk to human health from canine helminths, however only one third were aware of the means of transmission to humans. It is concluded that veterinarians can play an important role in increasing the level of awareness of canine zoonotic parasites.

Animals↗
PubMed1999

Effect of topical rh-TGF-beta 1 on second intention wound healing in horses.

OBJECTIVE: To investigate the effects on wound healing of transforming growth factor-beta 1 as a topical treatment to full-thickness, excisional wounds of the distal limb of horses. DESIGN: A randomised block study using four horses, each with wounds assigned to four treatment groups. ANIMALS: Four adult Standardbred geldings. PROCEDURE: Four, 4 cm2, full-thickness wounds were created on the dorsomedial and dorsolateral aspect of the metacarpus or metatarsus of each limb of four horses, giving a total of 64 wounds. For each limb, wounds were randomly assigned to four treatment groups: no treatment (control), carrier (Methyl Cellulose gel), 50 ng/wound rhTGF-beta 1 in carrier, and 500 ng/wound rhTGF-beta 1 in carrier. Wounds were treated on day 0 and day 8. Effects of treatment were evaluated on the basis of the presence of exuberant granulation tissue requiring excision, number of times excision was required, total wound area, area of epithelialisation, area of granulation, and histological evaluation of biopsy samples of wounds on day 8 and excised wounds on day 21. RESULTS: Topical application of TGF-beta 1 at the two concentrations studied had no significant effect on the total area of wounds (P = 0.7), the area of granulation tissue (P = 0.78), the area of epithelialisation (P = 0.92), histological assessment or subjective clinical assessment of wounds. CONCLUSION: TGF-beta 1 had no beneficial effects on wound healing. Additional trials are needed to test if it has value for wound treatment in horses.

Administration, Cutaneous↗
PubMed1998

Survey of predation by domestic cats.

OBJECTIVES: To calculate the proportion of house cats which were observed by their owners to have caught prey and to describe the characteristics of these cats. DESIGN AND PROCEDURE: A telephone questionnaire was administered to a randomly selected population of 458 cat owners in metropolitan Perth. Specific questions were asked about demographic characteristics, habits and diets of the cats, and whether the owners had observed their cats catch prey in the 12 month period preceding the survey. RESULTS: The owners of 36% of 644 cats had observed their cats with prey in the 12 month period preceding the survey. Cats which spent more time outside, were neutered, cross-bred, originated from households with only one or two cats or were not fed meat were significantly more likely to be observed to predate. The body condition and diet (other than feeding meat) of cats did not influence the reported frequency of predation. CONCLUSION: Although cats are only one factor involved in the reduction in the numbers and diversity of Australian wildlife, restriction of the outside activities of cats is likely to diminish predation, particularly in areas close to native vegetation.

Animals↗
PubMed1997

Excystation rates and infectivity of sporocysts of Sarcocystis cruzi exposed to different treatments and storages.

The effect of some chemical and anatomical factors on the excystability and infectivity in cell culture of sporocysts of Sarcocystis cruzi was investigated. A significantly (P < 0.001) higher excystation rate (ER) occurred when sodium bicarbonate was added to the excysting fluid at concentrations between 0.075 and 0.3 M. Sporocysts collected from different dogs had different ER. In contrast, although not uniformly distributed along the intestinal lumen, the sporocysts collected from the different tracts of the intestine showed similar ER. The period of storage did not affect the excystability of the sporocysts; however, it influenced the pattern of growth of the sporozoites in cell culture. Sporozoites excysted from sporocysts stored for approximately 2 years grew slower and produced significantly fewer merozoites compared to those excysted from sporocysts stored for 5-7 months.

Animals↗
PubMed1997

Sensitivities and specificities of two ELISA tests for detecting infection with Sarcocystis in cattle of Western Australia.

The accuracies of two ELISAs, one using antigen from merozoites of S. cruzi grown in vitro and the other using antigen from cystozoites of S. cruzi, for detecting infection of cattle with Sarcocystis, were evaluated by testing the sera of 303 cattle from 36 Western Australian herds. The results were compared with those obtained by digestion of oesophageal samples collected from the same animals. A similar proportion of infected animals were detected by the three methods. The sensitivity of the assays for detecting infected cattle was comparable (98 and 95% for the assay using antigen from merozoites and cystozoites, respectively), however the specificity (97%) of the assay which used antigen derived from merozoites was significantly higher (P < 0.001) than that (84%) which used antigen from cystozoites. When herds which had at least five animals sampled were considered, the same infected and non-infected herds were detected by the ELISA employing antigen from merozoites and the digestion methods (sensitivity and specificity of 100%). The sensitivity and specificity of the assay using cystozoite antigen were 100 and 67%, respectively. The kappa values for agreement beyond chance between the two ELISAs were calculated as 78% for the animal-based data and 72.5% for the herd-based data. We conclude that because of the high sensitivity and specificity of the ELISA using antigen derived from merozoites, this assay would be a useful and reliable tool for general sero-epidemiological studies into infection with Sarcocystis.

Abattoirs↗
PubMed1997

Class-specific antibody responses in cattle following experimental challenge with sporocysts or merozoites of Sarcocystis cruzi.

An ELISA using antigen produced from merozoites of Sarcocystis cruzi was developed to monitor specific IgM and IgG antibody, following challenge of cattle with either merozoites or sporocysts of S. cruzi. This assay was compared with an ELISA using antigen produced from the cystozoite stage of the parasite. Both ELISAs were able to detect significant increases in levels of circulating IgM and IgG antibodies against Sarcocystis in all challenged cows; however, the magnitude of the titres was greater in the ELISA which used the antigen derived from the merozoites. This immunoassay also detected increases in the levels of IgG earlier than did the assay using antigen derived from cystozoites of S. cruzi. Since this rise coincided with the presence of clinical signs, and was persistent for several weeks, the IgG-ELISA using antigen derived from merozoites appears to be suitable for the diagnosis of acute sarcocystiosis in cattle. Furthermore, since significant increases in the levels of circulating IgM and IgG antibodies against Sarcocystis were detected in the cows infected with merozoites of S. cruzi, it is evident that merozoites of S. cruzi cultured in vitro maintain their capability to replicate in the natural intermediate host.

Animals↗
PubMed1997

The prevalence of Serpulina pilosicoli in humans and domestic animals in the Eastern Highlands of Papua New Guinea.

In a survey of five villages in the Eastern Highlands of Papua New Guinea, Serpulina pilosicoli was isolated from rectal swabs from 113 of 496 individuals (22.8%). Colonization rates ranged from 22.6-30.1% in four of the villages but was only 8.6% in the other village. In comparison colonization was demonstrated in only 5 of 54 indigenous people (9.3%) and none of 76 non-indigenous people living in an urban environment in the same region. Colonization did not relate to reported occurrence of diarrhoea, age, sex, or length of time resident in a village. A second set of 94 faecal specimens was collected from 1 village 6 weeks after the first set. S. pilosicoli was isolated from 27 of 29 individuals (93.1%) who were positive on the first sampling and from 7 of 65 individuals (10.8%) who previously were negative. In this case, isolates were significantly more common in watery stools than in normal stools. The annual incidence of infection in the village was calculated as 93.6%, with an average duration of infection of 117 days. S. pilosicoli could not be isolated from any village pig (n = 126) despite its confirmed presence in 17 of 50 commercial pigs (34.0%) sampled at a local piggery. Four of 76 village dogs (5.3%) and 1 of 2 village ducks were colonized with S. pilosicoli, suggesting the possibility of cross transmission between humans and animals.

Adolescent↗
PubMed1997

Genetic differentiation of Australian isolates of Mycobacterium tuberculosis by pulsed-field gel electrophoresis.

As part of an epidemiological study of tuberculosis in Australia, 84 isolates of Mycobacterium tuberculosis from patients were analysed by pulsed-field gel electrophoresis (PFGE). The isolates were genetically heterogeneous, with 66 different DNA banding patterns obtained following digestion of genomic DNA with Dra1 and 53 patterns with Xba1. When the results were compared with those previously obtained in restriction fragment length polymorphism analysis (RFLP), in 87% of cases the results with Dra1 were consistent with those obtained with insertion sequence IS6110 as a probe in RFLP. However, PFGE was able to differentiate four of eight isolates which were identical with IS6110 typing. The high polymorphism amongst strains and the high average age of the patients (51 years) suggested that most organisms were cultured from patients who had reactivation of existing infections. Isolates with identical DNA patterns were found in different states of Australia, but no one strain predominated in any area. This suggests that tuberculosis has been introduced into Australia from various sources.

Adolescent↗
PubMed1997

Differentiation of Australian isolates of Mycobacterium paratuberculosis using pulsed-field gel electrophoresis.

OBJECTIVES: To examine strain variation amongst Australian isolates of Mycobacterium paratuberculosis. DESIGN: Pulsed field gel electrophoresis was optimised for differentiation of M paratuberculosis strains, and this typing technique was then applied to a collection of Australian isolates. PROCEDURE: DNAs from 35 Australian isolates of M paratuberculosis and a UK reference strain were digested with one or other of three restriction endonucleases. The banding patterns obtained after pulsed field gel electrophoresis of the DNA fragments were compared. RESULTS: The Australian isolates were divided into two groups on the basis of their DNA banding pattern. Both were different from the UK reference strain. Seven isolates from cattle in Victoria and the Northern Territory had the same pattern as five isolates from alpacas in Victoria and Western Australia. Another 20 isolates from cattle in Victoria, Western Australia and the Northern Territory had the same pattern as isolates from two sheep and a goat in New South Wales. CONCLUSION: Pulsed field gel electrophoresis was a useful tool for strain typing of M paratuberculosis, and could be used to study the transmission of strains in Australia.

Animals↗
PubMed1996

Viability of the sporocysts of Sarcocystis cruzi after exposure to different temperatures and relative humidities.

The effect of temperature and relative humidity (RH) on the survival of sporocysts of S. cruzi were investigated in vitro. Under all experimental conditions (temperature of 4 degrees C, 37 degrees C, or room temperature; RH of 18%, 75%, or 100%) some sporozoites retained their viability to excyst for at least 90 days. The best conditions for survival were 4 degrees C at 100% RH (more than 240 days) and 37 degrees C at 18% RH (more than 180 days). Sporocysts maintained at room temperature at all humidities had the lowest level of survival. It is concluded that sporocysts of S. cruzi are able to survive in most environments for several months and that the fluctuation of the daily ambient temperature is likely to influence the viability of the sporocysts.

Animals↗