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Biomedical subjects

John Campbell

Publications and source records attributed to John Campbell.

32 records · Page 2Linked to original sources
PubMed2004

Shiga toxin-producing Escherichia coli in the feces of Alberta feedlot cattle.

Shiga toxin-producing Escherichia coli (STEC) are a public health concern. Bacterial culture techniques commonly used to detect E. coli O157:H7 will not detect other STEC serotypes. Feces from cattle and other animals are a source of O157:H7 and other pathogenic serotypes of STEC. The objective of this study was to estimate the pen-level prevalence of Shiga toxins and selected STEC serotypes in pre-slaughter feedlot cattle. Composite fecal samples were cultured and a polymerase chain reaction (PCR) was used to detect genes for Shiga toxins (stx1 and stx2) and genes for O157:H7, O111:H8, and O26:H11 serotypes. Evidence of Shiga toxins was found in 23 pens (92%), O157:H7 in 2 (8%), O111:H8 in 5 (20%), and O26:H11 in 20 (80%) of the 25 pens investigated. Although pen-level prevalence estimates for Shiga toxins and non-O157 serotypes seem high relative to O157:H7, further effort is required to determine the human health significance of non-O157 serotypes of STEC in feedlot cattle.

Alberta↗
PubMed2003

Upward trends in the incidence of neck of femur fractures in the elderly.

AIM: A recent paper by Fielden and colleagues suggested the incidence of neck of femur fractures among those aged 65 years and older underwent a much smaller increase during the 1990s than had previously been predicted. Given the importance of neck of femur fractures in New Zealand we sought to re-examine the conclusions of Fielden and colleagues, paying close attention to case selection. METHODS: Cases were selected from patients discharged by New Zealand public hospitals, with close attention paid to the inclusion criteria. Readmissions and day patients were excluded. RESULTS: Twenty eight per cent of the cases we identified were excluded as either readmissions or day patients. The resulting yearly incidence estimates were generally lower than those reported by Fielden and colleagues but the upward trends in incidence were stronger. Similarly, our estimates of the trends in age-specific rates for women showed the decline in these rates to be much less significant than that reported by Fielden and colleagues. CONCLUSIONS: Age-group-specific rates of neck of femur fracture have not declined as much as Fielden and colleagues suggested. Case selection can have a significant effect on estimated incidence and trends derived from hospital data.

Aged↗
PubMed2003

Psuedoaneurysm of the superficial femoral artery resulting from stingray envenomation.

Stingray envenomations usually result in minor injuries with localized symptoms. In some cases the injury incurred is more serious, resulting in significant morbidity if not adequately treated. We report a case of pseudoaneurysm of the superficial femoral artery resulting from a stingray envenomation in a young female. Stingray venom is known to have necrosing properties in human tissues and in this case this led to graft failure requiring surgical repair. This case emphasizes the insidious nature of stingray venom and the necessity of extensive surgical debridement for more significant envenomations.

Adult↗
PubMed2003

Setting standards based on patients' views on access and continuity: secondary analysis of data from the general practice assessment survey.

OBJECTIVES: To examine patients' views on access and continuity in general practice to derive quality standards. DESIGN: Secondary analysis of data from general practice research studies and routine quality assessment activities undertaken by practices and primary care trusts. SETTING: General practice. PARTICIPANTS: General practice patients. RESULTS: Satisfactory standards of access were next day appointments with general practitioners and a 6-10 minute wait for consultations to begin. A satisfactory level of continuity was seeing the same general practitioner "a lot of the time." Standards varied with the analytic method used and by sociodemographic group. CONCLUSIONS: Standards expected by patients in primary care can be derived from linked report-assessment pairs. Patients may have expectations of access that are in excess of government targets. Patients also have high expectations of continuity of care. It is unclear the degree to which such standards are reliable or valid, how conflicts between access and continuity should be resolved, or how these standards relate to other priorities of patients such as high quality interpersonal care.

Adolescent↗
PubMed2003

Comparison of the diagnostic sensitivity of a commercially available culture kit and a diagnostic culture test using Diamond's media for diagnosing Tritrichomonas foetus in bulls.

A number of different culture media have been described for use in the diagnosis of Tritrichomonas foetus infection in bulls, and recently, a commercial culture kit has become available. The objective of this study was to compare the sensitivity of 2 culture-based diagnostic tests for T. foetus in bulls. One test used a commercial kit for transport and culture of the samples. The other test used a thioglycollate transport medium (TFTM) for transport and a modified Diamond's medium (MDM) for culture of the samples. Twenty-one bulls infected with T. foetus were sampled repeatedly. On each sampling day, samples collected from the left and right sides of the bull were tested with one of the 2 diagnostic tests being compared. The effect of the type of diagnostic test on the outcome of the test was evaluated with a chi-square test for the calculated odds ratio. Because repeated tests from the same bull cannot be considered independent measures, unadjusted chi-square tests were adjusted for the effect of clustering by bull. Samples tested using the commercial kit were 6.95 times as likely to be positive as samples tested with a diagnostic test using MDM (P < 0.001).

Animals↗
PubMed2003

Sample collection factors affect the sensitivity of the diagnostic test for Tritrichomonas foetus in bulls.

The current diagnostic test for Tritrichomonas foetus involves the culture of collected preputial or vaginal samples. In an earlier study, which evaluated sampling tools for use with bulls, it was observed that the sensitivity of the diagnostic test was higher for 2nd samples collected from the right side of the prepuce than it was for samples collected 1st from the left side. The study described in this paper was conducted to evaluate which of these factors was responsible for the effect on diagnostic sensitivity. Twenty-nine bulls infected with T. foetus were repeatedly sampled in a 2-factor cross-over design. Samples taken from the right side of the prepuce were 4 times as likely to be positive as samples taken from the left side (P = 0.03). Other factors did not have a significant effect on the outcome of the diagnostic test. Unexpected factors may affect the sensitivity of the diagnostic test for T. foetus.

Animals↗
PubMed2003

Diagnosis of trichomoniasis in 'virgin' bulls by culture and polymerase chain reaction.

The diagnostic test for Tritrichomonas foetus in bulls is microscopic examination of cultured preputial samples. Trichomonads other than T. foetus can be present in a preputial sample. Both a staining technique and a polymerase chain reaction assay were useful in differentiating between T. foetus and another trichomonad observed in samples from virgin bulls.

Animals↗
PubMed2002

A longitudinal study of gastrointestinal parasites in Canadian dairy farms. The value of an indirect Ostertagia ostertagi ELISA as a monitoring tool.

The general objective of this study was to evaluate a crude Ostertagia ostertagi antigen enzyme-linked immunosorbent assay (ELISA) for monitoring gastrointestinal parasites in lactating dairy cattle. A longitudinal study of gastrointestinal parasites in lactating dairy cows was carried out in 38 herds in four provinces of Canada (Prince Edward Island, Quebec, Ontario and Saskatchewan) from September 1999 to October 2000. Bulk tank milk, cow milk, serum and fecal samples were collected monthly or quarterly from all these farms. Information on herd management factors was collected by a standard questionnaire and individual cow production data were obtained from an electronic database. The overall mean optical density ratio (ODR) was 0.30 and ranged from -0.05 to 1.55. Although a clear seasonal pattern was not observed, the ODR values tended to decrease during the housing period and start increasing in the spring before the cows went out to pasture. The second and third or greater lactation cows had significantly higher ODR values compared with first lactation animals. The individual cow ODR had a very low correlation with individual squared root fecal egg counts but showed a reasonably high correlation when herd averages values were computed (r=0.73). A moderate correlation (r approximately 0.50) between the bulk tank and herd average ODR was observed. Milk yield was negatively associated with individual cow milk ODR and a quadratic effect on ODR was observed for days in milk. Twenty-eight of the herds participated in a clinical trial of eprinomectin (Ivomec Eprinex) treatment at calving. The cow level ODR values determined late in the previous lactation had a marginally significant effect (P=0.07) on treatment response, suggesting that high OD cows responded better to the anthelmintic treatment. However, because of the small sample size available in this model, more research is needed to better understand this relationship. In conclusion, the indirect ELISA using an O. ostertagi crude antigen appears useful as a technique for monitoring gastrointestinal parasite burdens in adult dairy cows and holds promise as a potential predictor of response to anthelmintic treatment.

Animal Husbandry↗
PubMed2002

Microarray analysis of gene expression during bacteriophage T4 infection.

Genomic microarrays were used to examine the complex temporal program of gene expression exhibited by bacteriophage T4 during the course of development. The microarray data confirm the existence of distinct early, middle, and late transcriptional classes during the bacteriophage replicative cycle. This approach allows assignment of previously uncharacterized genes to specific temporal classes. The genomic expression data verify many promoter assignments and predict the existence of previously unidentified promoters.

Bacteriophage T4↗
PubMed2002

The use of negative binomial modelling in a longitudinal study of gastrointestinal parasite burdens in Canadian dairy cows.

The epidemiology of bovine gastrointestinal nematodes was investigated through a 1-year (October 1999 to September 2000) longitudinal study in 38 Canadian dairy herds from 4 different provinces (Prince Edward Island, Quebec, Ontario, Saskatchewan). For each herd, fecal egg counts from 8 randomly selected animals were performed on a monthly or quarterly basis. Larval cultures were performed once, to determine the species breakdown of the parasites. All producers were interviewed regarding herd management practices. The observed fecal egg counts were low in this study, with a range from 0 to 419 nematode eggs per 5 g of feces. The mean count was 9.8 and the median was 1. Standard transformations failed to normalize the data, which followed an over-dispersed Poisson distribution. A zero inflated negative binomial model was applied to assess factors that would influence the fecal egg counts. Identified associations were: egg counts were lowest in the winter and highest in the late spring; first-lactation cattle had higher counts than older cows; if manure was spread mechanically on pastures used by lactating cattle the egg counts were higher; and if manure was spread on heifer-pastures, the adult cows had lower counts. In herds where pasture use was more extensive, the cattle had higher fecal egg counts. The difference in pasture exposure was found to be a main contributor to an observed difference in fecal egg counts among herds in the 4 provinces.

Animal Husbandry↗
PubMedDate not supplied

Getting evidence into practice using an asthma desktop tool.

BACKGROUND: Failure to utilise evidence in asthma care is leading to avoidable asthma symptoms for sufferers and costs to health services. OBJECTIVE: This article describes a collaboration between a division of general practice and a university department of general practice to improve uptake of evidence based asthma treatments and to better educate patients. DISCUSSION: The division of general practice drew upon lessons from university based research within its locality producing an 'asthma desktop tool'. This combined evidence based clinical guidance for practitioners with educational information for patients in paper and electronic formats. The tool has been provided to all local general practices, hospitals and pharmacists to facilitate uptake of best practice guidelines and enhance patient knowledge and understanding. The division has directly responded to university based research producing a practical solution to some of the identified problems. This demonstrates that with appropriate resources and support, divisions are well placed to translate research into practice, and combine with academic institutions to produce worthwhile results.

Academic Medical Centers↗
PubMedDate not supplied

Developing an educational reminder system for a handheld encounter log.

BACKGROUND AND OBJECTIVES: Medical students increasingly log patient encounters on handheld computers. Detailed patient records captured at the bedside would allow these log programs to complement medical education with automated reminders. We evaluated progress toward this goal. METHODS: A series of electronic student encounter logs (ESEL) were designed to quickly record common diagnoses in a family medicine clerkship. Common diagnoses were organized in a shallow, broad-tree structure that locates many concepts with one to four taps. Third-year clerks' ESEL records of patient problems were evaluated longitudinally and across two similar clerkships. Grading criteria were introduced to encourage attention to target problems, especially infrequently reported psychosocial issues. A pilot reminder system in ESEL-4, the latest version of the computer application program, included 17 high-specificity reminders. Students' viewing of reminders was monitored. RESULTS: Students recorded complex patients in ESEL-4 and entered 80% of patients during office hours. ESEL grading generated anxiety but was associated with significantly increased and plausible documentation of tobacco abuse, depression, and alcohol abuse. Students viewed titles of about 25% of generated reminders but reviewed less than 1% of reminders in detail. CONCLUSIONS: Students using ESEL-4 document plausibly complex patients, usually during office hours. Grading probably improves completeness and accuracy. Diagnosis-driven educational reminder systems are possible but do not yet capture students' attention.

Adult↗