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Biomedical subjects

R F Webb

Publications and source records attributed to R F Webb.

At least 19 recordsLinked to original sources
PubMed1993

False negative bone scan in a female runner.

Stress fractures are more prevalent in today's fitness cognizant society. Stress fractures of the femoral neck are common and present with specific symptoms and findings. The diagnosis is based on clinical history, physical exam, radiography, bone scintigraphy, and computed tomography (C.T.) scans. The triple-phase bone scan is the most sensitive test for the diagnosis of stress fractures and is considered the gold standard for the diagnosis of the occult stress fracture. This case presents a 42-yr-old female marathon runner who presented with hip pain and clinical symptoms indicating a stress fracture of the femoral neck. Initial radiographs and a triple-phase bone scan were negative. When symptoms persisted, a repeat x-ray revealed a femoral neck fracture of the superior surface. In spite of a false negative bone scan, clinical suspicion allowed appropriate treatment of this femoral neck stress fracture. Nondiagnosed stress fractures of the femoral neck may lead to severe disability, including avascular necrosis of the femoral head. Therefore, clinical index of suspicion is very important even if ancillary tests are nondiagnostic.

Adult↗
PubMed1986

The prevalence of anthelmintic resistance in sheep nematodes on the central tablelands of New South Wales.

A survey was undertaken to assess the prevalence of anthelmintic resistance in sheep nematode populations on 40 commercial farms distributed throughout the central tablelands of New South Wales. Representatives of the 2 major groups of broad spectrum anthelmintics with different modes of action (thiabendazole and levamisole) were used at the manufacturer's recommended dose rates. Efficacy was assessed on the basis of the reduction in faecal strongyle egg counts 7 days after treatment. An efficacy of less than 90% using both anthelmintics was obtained on 4 farms. Thiabendazole had an efficacy of less than 90% on a further 21 farms and levamisole had an efficacy of less than 90% on an additional 4 farms. There was no evidence of anthelmintic resistance on 8 farms, while the remaining 3 had insignificant parasite burdens. Based on larval cultures from faeces, Ostertagia and Trichostrongylus were the most significant species in resistant populations. Haemonchus burdens were sporadic and levels of resistance relatively low. Nematodirus burdens were widespread but no evidence of resistance was detected.

Animals↗
PubMed1983

Bacteriological characteristics of Histophilus ovis and its relationship to similar bacteria.

Seventeen strains of Histophilus ovis were obtained from a variety of pathological conditions and geographical areas and were examined to determine the bacteriological characteristics of the organism. All were Gram-negative pleomorphic rods which only grew under micro-aerophilic conditions in media enriched with blood, serum or meat particles. All strains were catalase negative, indole positive and nitrate positive while most produced acid from glucose, fructose, galactose, mannose, xylose, mannitol and sorbitol. Eight strains were examined serologically and compared with two strains of Actinobacillus seminis. In agglutination and precipitation tests, all strains of H ovis appeared antigenically identical and showed antigenic relationships to A seminis. Results of complement fixation tests confirmed the close, if not identical, antigenic relationship of H ovis and A seminis. It is suggested that H ovis and A seminis are biochemical variants of the same organism.

Actinobacillus↗
PubMed1983

Clinical findings and pathological changes in Histophilus ovis infections of sheep.

The Gram-negative pleomorphic bacterium Histophilus ovis was incriminated as the cause of natural cases of epididymitis in rams, polyarthritis in lambs, mastitis and abortion in ewes. Epididymitis was sporadic in occurrence, unilateral in distribution and varied from acute to chronic in degree. Polyarthritis affected recently born lambs and resulted in acute lameness and subsequent debility. Mastitis was rare in occurrence, unilateral in distribution, acute and gangrenous in type. Abortion was also rare and manifested by a specific haemorrhagic placentitis. These four conditions were reproduced experimentally. The clinical, pathological and histopathological changes associated with field and experimental cases are described.

Abortion, Veterinary↗
PubMed1980

Evaluation of procedures for the diagnosis of Brucella ovis infection in rams.

Procedures for the diagnosis of Br. ovis infection in rams were evaluated by examining 10 rams artificially infected by preputial inoculation. Observations were undertaken at weekly intervals for 1 year to follow changes in clinical, bacteriological and serological findings. Clinical lesions were detected in 1 ram 3 weeks after inoculation and in all rams by 8 weeks; lesions were undetectable in 3 rams at the completion of the trial. The presence of inflammatory cells in semen samples was the earliest indication of infection being demonstrated in 2 rams at 2 weeks and in all rams by 8 weeks; subsequently 86% of samples were positive. Br. ovis was detected in semen smears from 3 rams at 4 weeks but only one in all rams (at 27 weeks); overall 52% of semen smears were positive from 4 weeks onwards. Br. ovis was cultured from semen of 5 rams after 4 weeks and from all rams at 5 weeks; therafter 97% of samples were positive. All rams developed significant titres to the CFT between 2 and 9 weeks; therafter the CFT was a reliable indication of infection in 6 rams, highly suggestive in 3 and unreliable in one. By 8-10 weeks all rams developed significant titres to the IHA which were then maintained in all rams for the remainder of the trial.

Animals↗
PubMed1979

The incidence of thiabendazole resistance in field populations of Haemonchus contortus on the northern tablelands of New South Wales.

A survey was undertaken to assess the incidence of thiabendazole resistance in field populations of H. contortus in sheep flocks on 40 farms distributed throughout the sheep grazing area of the northern tablelands of New South Wales. Treatment with thiabendazole at 66 mg/kg reduced H. contortus ova output by 96-100% in 18 flocks while in the remaining 22 there was a range of responses down to levels where the anthelmintic was without apparent effect. Factors which may contribute to the high incidence of anthelmintic resistance are discussed and the possibility of widespread resistance occurring in other sheep raising areas is considered.

Animals↗