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Biomedical subjects

K A Dunn

Publications and source records attributed to K A Dunn.

At least 19 recordsLinked to original sources
PubMed2003

A survey of equine abortion, stillbirth and neonatal death in the UK from 1988 to 1997.

REASONS FOR PERFORMING STUDY: A detailed review of laboratory records for equine abortion is fundamental in establishing current disease trends and suggesting problems important for further research. OBJECTIVES: To review the causes of abortion and neonatal death in equine diagnostic submissions to the Animal Health Trust over a 10 year period. METHODS: The diagnoses in 1252 equine fetuses and neonatal foals were reviewed and analysed into categories. RESULTS: Problems associated with the umbilical cord, comprising umbilical cord torsion and the long cord/cervical pole ischaemia disorder, were the most common diagnoses (38.8%: 35.7% umbilical cord torsion and 3.1% long cord/cervical pole ischaemia disorder). Other noninfective causes of abortion or neonatal death included twinning (6.0%), intrapartum stillbirth (13.7%) and placentitis, associated with infection (9.8%). E. coli and Streptococcus zooepidemicus were the most common bacteria isolated. Neonatal infections not associated with placentitis accounted for 3.2% of incidents; and infections with EHV-1 or EHV-4 for 6.5%. CONCLUSIONS: Definitive diagnosis of equine abortion is possible in the majority of cases where the whole fetus and placenta are submitted for examination. POTENTIAL RELEVANCE: Given the high incidence of umbilical cord torsion and related problems as causes of abortion in UK broodmares, more research on factors determining umbilical cord length and risk of torsion is essential.

Abortion, Veterinary↗
PubMed2001

Substitution rates in Drosophila nuclear genes: implications for translational selection.

The relationships between synonymous and nonsynonymous substitution rates and between synonymous rate and codon usage bias are important to our understanding of the roles of mutation and selection in the evolution of Drosophila genes. Previous studies used approximate estimation methods that ignore codon bias. In this study we reexamine those relationships using maximum-likelihood methods to estimate substitution rates, which accommodate the transition/transversion rate bias and codon usage bias. We compiled a sample of homologous DNA sequences at 83 nuclear loci from Drosophila melanogaster and at least one other species of Drosophila. Our analysis was consistent with previous studies in finding that synonymous rates were positively correlated with nonsynonymous rates. Our analysis differed from previous studies, however, in that synonymous rates were unrelated to codon bias. We therefore conducted a simulation study to investigate the differences between approaches. The results suggested that failure to properly account for multiple substitutions at the same site and for biased codon usage by approximate methods can lead to an artifactual correlation between synonymous rate and codon bias. Implications of the results for translational selection are discussed.

Animals↗
PubMed2000

The downside of adolescent employment: hazards and injuries among working teens in North Carolina.

Occupational injuries are major adverse outcomes of teen employment in the United States. Using data from a survey of teens employed in three different retail trade settings (food service, grocery, and other retail) in the state of North Carolina, we examine how experience, gender, work setting, and the pace of work are associated with hazard exposures and injury experiences. Multivariate analyses show that, after controlling for individual and job-level variables, perceived work-pace pressure and hazard exposure are positively associated with variation in the types of injury experiences. We emphasize the need to include characteristics of the workplace and the labor process when assessing the adverse consequences of work on adolescent well-being.

Accidents, Occupational↗
PubMed2000

GM1-gangliosidosis in a cross-bred dog confirmed by detection of GM1-ganglioside using electrospray ionisation-tandem mass spectrometry.

The post-mortem diagnosis of lysosomal storage diseases can be confounded by the unavailability of suitable material. Here we report the diagnosis of GM1-gangliosidosis in a cross-bred dog, from which only formalin-fixed brain was available, by a combination of electron microscopy and the detection of elevated levels of GM1-ganglioside within the tissue using the novel technique of electrospray ionisation tandem mass spectrometry. Electron microscopic examination of ultrathin sections of resin-embedded tissue revealed cytoplasmic inclusions (membranous cytoplasmic and zebra bodies) in brain stem and cerebellar neurons that were characteristic of a gangliosidosis. Glycolipids were extracted from the fixed tissue and analysed by tandem mass spectrometry. Two major ions were detected, which corresponded to GM1 (d18:1-C18:0) and Gm1 (d20:1-C18:0). Their identity was confirmed by comparison of their fragmentation patterns with those of authentic standards. The concentration of GM1 was approximately sixfold higher on a wet weight basis than in the brain of a normal control dog, confirming the diagnosis of GM1-gangliosidosis.

Animals↗
PubMed2000

Comparative genomic hybridization (CGH) in dogs--application to the study of a canine glial tumour cell line.

Recurrent chromosome aberrations are associated with many human cancers. Detailed cytogenetic analysis of tumors has benefited enormously from the development of molecular cytogenetic techniques based on fluorescence in situ hybridization (FISH). Comparative genomic hybridization (CGH) is a recently developed FISH technique that allows a rapid and comprehensive identification of imbalanced genomic material in tumour DNA. Comparative genomic hybridisation has been used widely in human medicine to evaluate losses and gains of tumour DNA isolated from a variety of sources, including fresh samples, cell-culture material and archival specimens, and has been instrumental in identifying sites in the human genome which contain genies involved in tumour development and progression. This report describes the first application of CGH in the dog, illustrated by the analysis of DNA isolated from a canine glial tumour cell line.

Animals↗
PubMed2000

Rates of nucleotide substitution and mammalian nuclear gene evolution. Approximate and maximum-likelihood methods lead to different conclusions.

Rates and patterns of synonymous and nonsynonymous substitutions have important implications for the origin and maintenance of mammalian isochores and the effectiveness of selection at synonymous sites. Previous studies of mammalian nuclear genes largely employed approximate methods to estimate rates of nonsynonymous and synonymous substitutions. Because these methods did not account for major features of DNA sequence evolution such as transition/transversion rate bias and unequal codon usage, they might not have produced reliable results. To evaluate the impact of the estimation method, we analyzed a sample of 82 nuclear genes from the mammalian orders Artiodactyla, Primates, and Rodentia using both approximate and maximum-likelihood methods. Maximum-likelihood analysis indicated that synonymous substitution rates were positively correlated with GC content at the third codon positions, but independent of nonsynonymous substitution rates. Approximate methods, however, indicated that synonymous substitution rates were independent of GC content at the third codon positions, but were positively correlated with nonsynonymous rates. Failure to properly account for transition/transversion rate bias and unequal codon usage appears to have caused substantial biases in approximate estimates of substitution rates.

Animals↗
PubMed2000

Diagnostic evaluation of patients with blunt abdominal trauma: a decision analysis.

OBJECTIVES: Using decision analysis, to compare the expected utility (EU) of diagnostic peritoneal lavage (DPL), computed tomography (CT), and ultrasonography (US) to determine the optimal modality for the evaluation of blunt abdominal trauma (BAT) in hemodynamically stable adults. METHODS: Data points for the decision analysis were obtained from three sources: 1) prevalence of BAT and the sensitivity and specificity of each diagnostic modality were determined through a criteria-based review of the literature; 2) rate of BAT necessitating immediate intervention, perioperative complication rate, and operative mortality rate were calculated using data from the authors' institution's trauma registry; and 3) outcome utilities were determined by telephone survey of adults in a random sample of households in the region. The decision tree was constructed and evaluated in standard fashion. For each diagnostic modality, the authors calculated the EU using the minimum, mean, and maximum sensitivity and specificity across a range of prevalence. Mean outcome utilities were used for each branch of the tree when calculating the EU. RESULTS: The EU of CT was consistently lower than the EUs of DPL and US at all levels of prevalence. However, the rank order of the EUs of US and DPL varied with the prevalence of BAT. When the prevalence was <30%, the EU of US was higher than that for DPL. When the prevalence was 30-40%, the EUs were similar. When the prevalence was >40%, the EU of US was less than that of DPL. CONCLUSIONS: Among institutions operating under constraints similar to those used in this model, the optimal diagnostic modality for the evaluation of BAT can be determined based on the sensitivity and specificity of the modality at their institution and the prevalence of BAT in their patient population.

Abdominal Injuries↗
PubMed1999

Traumatic brain injury in the United States: A public health perspective.

Traumatic brain injury (TBI) is a leading cause of death and disability among persons in the United States. Each year, an estimated 1.5 million Americans sustain a TBI. As a result of these injuries, 50,000 people die, 230,000 people are hospitalized and survive, and an estimated 80,000-90,000 people experience the onset of long-term disability. Rates of TBI-related hospitalization have declined nearly 50% since 1980, a phenomenon that may be attributed, in part, to successes in injury prevention and also to changes in hospital admission practices that shift the care of persons with less severe TBI from inpatient to outpatient settings. The magnitude of TBI in the United States requires public health measures to prevent these injuries and to improve their consequences. State surveillance systems can provide reliable data on injury causes and risk factors, identify trends in TBI incidence, enable the development of cause-specific prevention strategies focused on populations at greatest risk, and monitor the effectiveness of such programs. State follow-up registries, built on surveillance systems, can provide more information regarding the frequency and nature of disabilities associated with TBI. This information can help states and communities to design, implement, and evaluate cost-effective programs for people living with TBI and for their families, addressing acute care, rehabilitation, and vocational, school, and community support.

Adolescent↗
PubMed1998

Improving safety for teens working in the retail trade sector: opportunities and obstacles.

BACKGROUND: Using both quantitative and qualitative data, this study examined teen workers' perceptions about their work environments and the ways in which teens believe workplaces can be made safer. METHODS: We conducted telephone interviews (n = 117) and six focus groups (n = 49) with two separate samples of North Carolina teens who worked in the retail trade sector. RESULTS: Survey findings indicate one-fifth of teens used equipment they thought dangerous; nearly 40% always or often felt rushed at work; and about half received training on how to avoid injury. Teens in the focus groups expressed concerns about workplace physical hazards, the threat of assault, being rushed, and having little power in the work environment. They also indicated that their workplace safety training was ineffective and that child labor laws were unnecessary. CONCLUSIONS: In order to be effective, interventions targeted at working teens need to address the organization of work and adolescent-manager interaction patterns.

Accidents, Occupational↗
PubMed1998

Systemic infection by equid herpesvirus-1 in a Grevy's zebra stallion (Equus grevyi) with particular reference to genital pathology.

A severe multi-systemic form of equid herpesvirus-1 infection is described in an adult zebra stallion. There was multifocal necrotizing rhinitis, marked hydrothorax and pulmonary oedema, with viral antigen expression in degenerating epithelial cells, local endothelial cells and intravascular leucocytes of the nasal mucosa and lung. Specific localization of EHV-1 infection was seen in the testes and epididymides, including infection of Leydig cells and germinal epithelium, which would have facilitated venereal shedding of virus in life. The case provided a unique opportunity to study hitherto undescribed aspects of the pathogenesis of naturally occurring EHV-1 infection in the male equine genital tract. Restriction digests of the isolate demonstrated a pattern similar to that of EHV-1 isolates previously recovered from aborted zebra and onager fetuses.

Animals↗
PubMed1998

Teens at work: a statewide study of jobs, hazards, and injuries.

PURPOSE: Occupational injury is an ongoing and serious threat to American youth. However, little is known about the environments in which youth work or the hazards to which they are exposed. The purpose of this study was to document the patterns of work, exposures to hazardous equipment and situations, and work-related injury experiences of adolescents. METHODS: We identified a statewide targeted sample of North Carolina households with teens age 14-17 years and interviewed those who had ever worked for pay or worked on a farm. RESULTS: Five hundred sixty-two teens from 700 eligible households reported that they had worked non-farm jobs for pay. One-third were paid for work before age 14 years; two-thirds had held more than one paid job. Place of employment was most often someone's home, a retail store, or a restaurant. Common jobs were lawn care worker, cashier, and dishwasher. Common hazards to which teens were exposed included ladders or scaffolding; forklifts, tractors or riding mowers; and working around loud noises. Over half were injured at least once while working a paid job, most often from being cut or burned. CONCLUSIONS: Work among youth is common. Teens hold a variety of jobs, mostly in the retail trade and the service sector, exposing them to hazardous equipment and situations. Injuries at work are frequent and some are serious. This study supports the need to include an occupational history and work-related safety counseling in clinical encounters with adolescents.

Accidents, Occupational↗
PubMed1998

Intravenous ketorolac vs intravenous prochlorperazine for the treatment of migraine headaches.

OBJECTIVE: To compare i.v. ketorolac with i.v. prochlorperazine as the initial treatment of migraine headaches in the ED. METHODS: A prospective, double-blind comparison study was performed, using a convenience sample of 64 patients suffering from migraine headaches presenting to the ED at a tertiary care university teaching hospital. Patients were randomly assigned to receive either 10 mg of prochlorperazine i.v. or 30 mg of ketorolac i.v.. Patients scored the severity of their headaches using a 10-cm visual analog pain scale. An initial mark was made on the scale at the time of entry into the study and later another mark was made on a new unmarked pain scale 1 hour after medication administration. Changes in pain scores within each treatment group and between groups were analyzed using the Wilcoxon rank sum test. RESULTS: Prior to treatment, the patients assigned to receive prochlorperazine had a median score of 9.2 cm (mean +/- SD pain score of 8.3 cm +/- 2.1 cm), while the patients receiving ketorolac had a median score of 9.0 (mean pain score of 8.4 cm +/- 1.7 cm). There was no significant difference between the pain scores of the participants in the 2 groups prior to treatment (p = 0.80). One hour after medication administration, the patients in the prochlorperazine group had a median score of 0.5 cm (mean 2.1 +/- 3.2 cm), while those patients receiving ketorolac had a median pain score of 3.9 (mean 4.0 +/- 3.3 cm). The decrease in pain score was significant for both groups of patients (p = 0.0001). The change in pain score for the patients in the prochlorperazine group (median 7.1) was significantly greater than the change in pain score for the patients in the ketorolac group (median 4.0; p = 0.04). CONCLUSION: Although both drugs were associated with a significant reduction in pain scores, benefit over a placebo agent was not tested. Furthermore, the patients who received prochlorperazine i.v. for migraine headaches had a statistically significant greater decrease in their pain scores than did those receiving ketorolac i.v.

Adult↗
PubMed1998

Prospective evaluation of a teaching model to determine competency in performing flexible sigmoidoscopies.

OBJECTIVE: There are limited objective criteria for determining competency in performing flexible sigmoidoscopies. The authors developed a teaching model using eight objective criteria that measured both cognitive and technical skills in performing flexible sigmoidoscopies. The objective was to determine whether the teaching model was a valid method and then to compare it to a commonly used Overall Competence Score or independent observer method. METHODS: A total of 120 procedures with 10 residents were evaluated using the two methods. Eight objective parameters had been determined before validating the teaching model. Preset criteria determined competency on a single procedure, and competent performance on five procedures in a row determined certification to independently perform procedures. The teaching model was separately tested for validity and then compared with the independent observer method. RESULTS: A total of 120 procedures were graded using the teaching model method: 73 competent and 47 incompetent. Six of the seven objective parameters were associated with competency in the teaching model method. The eighth objective parameter was excluded because of lack of variation. Fifty of the 120 procedures were graded using the independent observer method: 36 competent and 14 incompetent. Two of the seven objective parameters were associated with competency in the independent observer method. Comparison of the two methods revealed seven discrepancies regarding competent and incompetent procedures. The correlation between the two methods was 0.71. CONCLUSION: The teaching model method offers objective criteria to evaluate skill in performing flexible sigmoidoscopies.

Clinical Competence↗
PubMed1997

Naturally occurring persistent and asymptomatic infection of the guttural pouches of horses with Streptococcus equi.

During an outbreak of strangles on a farm with approximately 1500 horses, the spread of Streptococcus equi infection was monitored by repeated nasopharyngeal swabbing and culture. In order to control the infection and prevent new introductions of strangles on to the premises, a system of quarantine and swabbing of cases and all incoming animals was instituted. Long-term carriage of the organism was detected in four clinically healthy convalescent animals, and in two of 350 new ponies; it persisted for between seven and 39 months, but it was detected only intermittently by the culture of swabs which was a much less sensitive method than the culture of guttural pouch lavages taken by endoscopy (45 per cent v 88 per cent sensitivity, respectively, for any single sample). Repeated swabs were often negative for several weeks between positive samples. Nonetheless, in all but one of the long-term carriers, S equi was detected by culture of repeated swabs taken over a period of less than two to three months. Infection was detected unilaterally in the guttural pouches of five of the carriers and was accompanied by large numbers of neutrophils in the lavage samples whether or not there was empyema. Abnormalities of the affected guttural pouches were detectable by radiography but only after the instillation of contrast medium. The study indicated that clinically healthy long-term carriers of S equi present a serious risk of spreading strangles, particularly because they may be detected only by repeated nasopharyngeal swabbing over two to three months.

Animals↗
PubMed1997

Do pulse checks cause a significant delay in the initial defibrillation sequence?

This study was undertaken to determine if checking for a pulse between initial defibrillations causes a clinically significant delay in the administration of the defibrillations. Ten emergency department nurses and 10 emergency medicine resident physicians were timed delivering three successive defibrillations (200, 300 and 360 J) to a manikin under three randomly assigned scenarios: (1) without pulse checks; (2) with pulse checks performed by an assistant; and (3) with pulse checks performed by the participant. All participants performed the three defibrillation scenarios using three different models of defibrillators. Repeated measures analysis of variance was used to compare mean defibrillation times for the three scenarios. The mean time was 20.4 +/- 1.0 s for defibrillation without pulse checks; 20.2 +/- 1.2 s with pulse checks by an assistant and 22.0 +/- 2.0 s with pulse checks by the participant. There was a statistically significant difference between no pulse checks and pulse checks by the participant. No statistically significant difference was noted between no pulse checks and pulse checks by an assistant. We conclude that checking for a pulse does cause a statistically significant delay in the administration of defibrillations. This difference, however, is not likely to be clinically relevant.

Analysis of Variance↗
PubMed1997

Farm work is dangerous for teens: agricultural hazards and injuries among North Carolina teens.

Children who work in agriculture suffer more than 23,000 injuries and 300 fatalities on American farms every year. Using survey data collected from a random sample of working teens (ages 14 to 17) in North Carolina, the authors analyze the farm-based hazard exposure and injury experiences of teens who work on farms. The group of farmworking teens (N = 141) is 72 percent male, has a mean age of 16.6 years, and is, on average, in the 10th grade. The data show that teens working on farms in North Carolina are exposed to significant safety hazards throughout their farmworking careers. A majority of the respondents in this group of farmworkers reported exposure to tractors, large animals, all-terrain vehicles, farm trucks, and rotary mowers, and more than one-third reported exposure to pesticides and tobacco harvesters. Common reported injuries include insect stings, cuts, burns, and falls. The researchers find that gender, age, and farmwork experiences are related to variations in types of hazards to which teens are exposed and in the types of injuries they suffer. These variables also are related to the overall complexity of the teens' farmwork experiences and the burden of injury endured by teens.

Accidents, Occupational↗