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Biomedical subjects

K Orr

Publications and source records attributed to K Orr.

At least 19 recordsLinked to original sources
PubMed2001

Development of an assay for antibodies to Saccharomyces cerevisiae: Easy, cheap and specific for Crohn's disease.

OBJECTIVE: To develop a serological test to measure antibodies to Saccharomyces cerevisiae in patients with inflammatory bowel disease. METHODS: An ELISA to the mannan of S cerevisiae that is commercially available was developed. Sera were tested from randomly chosen sera specimens kept frozen at the University of Manitoba Inflammatory Bowel Disease Clinical and Research Centre, Winnipeg, Manitoba. Clinical diagnoses were kept blinded until the assay results were finalized. One hundred thirty-six sera were tested, including 51 with Crohn's disease, 32 with ulcerative colitis, one with indeterminate colitis and 16 other control subjects. Thirty-six samples were duplicates from patients already studied but were either run on separate days or drawn on different days. RESULTS: Using a cutoff of 15 binding units as a positive result, Crohn's disease was found to have a sensitivity of 53% but a specificity of 100% compared with ulcerative colitis. Compared with all other diagnoses (including ulcerative colitis), Crohn's disease had a sensitivity of 53% and a specificity of 96%. For patients with Crohn's disease only, those who were anti-S cerevisiae antibody (ASCA) positive (n=27) were significantly more likely to have proximal gastrointestinal disease and significantly less likely to have colonic or inflammatory type disease than those who were ASCA negative (n=24). The direct cost of this assay was $6.00 per positive test, and the total charge was set at $38.15. CONCLUSIONS: A reasonably inexpensive, easy and reproducible assay to assess for antibodies to S cerevisiae has been developed. Using a cutoff for positivity of 15 binding units, this test had a specificity of 100% for ruling out Crohn's disease and a lower (60%) sensitivity compared with ulcerative colitis. This test could identify a specific phenotype of patients with Crohn's disease as being more likely to have small bowel Crohn's disease and less likely to have colonic (isolated) or inflammatory disease, as opposed to fibrostenotic disease or penetrating disease. The test proved reliable when assaying samples drawn or assayed on different days.

Adult↗
PubMed2001

Enterotoxigenic Escherichia coli infection in captive black-footed ferrets.

Enterotoxigenic Escherichia coli with genes for heat stabile toxins Sta and STb was isolated from the gastrointestinal tract and multiple visceral organs of three adult and three juvenile black-footed ferrets (Mustela nigripes) that died in a captive breeding colony between 24 May 1998 and 2 July 1998. Similar isolates were obtained from rectal swabs of one adult and one juvenile that were clinically ill. All were fed a diet composed of mink chow, raw rabbit meat, beef liver powder, blood meal and lard. Escherichia coli of the same toxin genotype was isolated from the mixed ration. Clinical signs included sudden death, dehydration, anorexia and diarrhea. Necropsy lesions included acute enteritis with large numbers of rod shaped bacteria microscopically visible on intestinal villi.

Animals↗
PubMed2001

Psychiatric treatment and operational readiness: clinical guidelines for Air Force practice.

Clinical criteria for psychiatric illnesses that are career limiting to active duty Air Force personnel are defined in Air Force Instruction (AFI) 48-123. The terms used in the AFI are not sufficiently specific to the standards of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). The authors review AFI 48-123 for conditions commonly seen in Air Force mental health practice and offer clinical interpretation of this AFI to bring it into line with DSM-IV. As a result of this synthesis, decisions regarding which mental health conditions warrant medical evaluation board disposition are clearer and more uniform. Clinicians and administrators are encouraged to refer to this paper for assistance in making decisions on mental health patients.

Humans↗
PubMed1999

The use of amplified fragment length polymorphism (AFLP) in the isolation of sex-specific markers.

Sex identification is a problem in research and conservation. It can often be solved using a DNA test but this is only an option if a sex-specific marker is available. Such markers can be identified using the amplified fragment length polymorphism (AFLP) technique. This is usually a taxonomic method, as it produces a DNA fingerprint of 50-100 PCR bands. However, if male and female AFLP products are compared, sex-specific markers are confined to the heterogametic sex and can rapidly be identified. Once a marker is found, AFLP can be used to sex organisms directly or the marker can be sequenced and a standard PCR test designed.

Animals↗
PubMed1999

The Massachusetts forensic transition program for mentally ill offenders re-entering the community.

On April 1, 1998, the Massachusetts Department of Mental Health established the forensic transition program for mentally ill offenders. The primary goal of the statewide program, which follows clients for three months after their release from correctional facilities, is to coordinate services and assist in community reintegration. In the first year of the program, 233 mentally ill offenders received services. Seventy-four clients had been discharged as of April 1, 1999. At discharge 42 of the 74 clients (57 percent) were living in the community and were receiving mental health services. The other clients were hospitalized immediately after release (20 percent), reincarcerated (10 percent), hospitalized after a brief stay in the community (3 percent), or lost to follow-up (11 percent).

Adult↗
PubMed1998

A DNA test to sex most birds.

Birds are difficult to sex. Nestlings rarely show sex-linked morphology and we estimate that adult females appear identical to males in over 50% of the world's bird species. This problem can hinder both evolutionary studies and human-assisted breeding of birds. DNA-based sex identification provides a solution. We describe a test based on two conserved CHD (chromo-helicase-DNA-binding) genes that are located on the avian sex chromosomes of all birds, with the possible exception of the ratites (ostriches, etc.; Struthioniformes). The CHD-W gene is located on the W chromosome; therefore it is unique to females. The other gene, CHD-Z, is found on the Z chromosome and therefore occurs in both sexes (female, ZW; male, ZZ). The test employs PCR with a single set of primers. It amplifies homologous sections of both genes and incorporates introns whose lengths usually differ. When examined on a gel there is a single CHD-Z band in males but females have a second, distinctive CHD-W band.

Animals↗
PubMed1998

Genetic and environmental risk factors for Parkinson's disease in a Chinese population.

An epidemiological study of the environmental and genetic factors as well as the possible interplay between them was conducted among 215 patients with Parkinson's disease and 313 controls in a Chinese population in Hong Kong. In univariate analysis, a regular tea drinking habit was found to be a protective factor, which had not been reported before. Smoking (a protective factor), family history, duration of pesticide exposure (in years) in farming and pesticide exposure during farming in women (both risk factors) have been reported previously. In multivariate analysis, current smoking reached borderline significance at the 5% level and the variables, years exposed to pesticides and family history were significant at the 10% level. By contrast with the common occurrence of polymorphism of the CYP2D6 gene (a gene involved with xenobiotic metabolism) in white people, it is very rare in China and is not thought to be a significant factor contributing to Parkinson's disease in Chinese people.

Aged↗
PubMed1997

The effects of oral versus written instructions on parents' recall and satisfaction after pediatric appointments.

This study explored the differential effects of written versus oral instructions on parents' recall of information and satisfaction after pediatric appointments. Ninety-six parents completed descriptive information and satisfaction ratings, and four pediatricians completed ratings concerning the complexity level of the appointment. After the appointment, parents were randomly assigned to the Written condition (to receive a transcription of the pediatrician's instructions) or Oral condition (verbal instruction only). Parents were telephoned 5 to 7 days later to report their recall of instructions and satisfaction with the appointment. For the Oral condition parents only, more previous appointments with a given pediatrician were associated with greater parental satisfaction and recall of instructions, and more previous appointments and more time spent with the pediatrician were related to fewer forgotten instructions. Parental characteristics, such as age, number of children, and occupational status, were associated with satisfaction and accurate recall. Implications of these findings are discussed.

Adolescent↗
PubMed1995

Dosimetric considerations in treating mediastinal disease with mantle fields: characterization of the dose under mantle blocks.

PURPOSE: While the rationale for using mantle fields is well understood and the prescription of these fields is straightforward, the underlying complexity of the dose distributions that result is not generally appreciated. This is especially true in the choice of lung block design, which affects the dose to both the target volume as well as to the normal lung tissue. The key to the design of optimal lung blocks is the physician's perception of the complex relationship between the geometric and dosimetric aspects of heavily modified fields, as well as how the physical and anatomical properties of the target volume and the shape of the patient's lungs relate to the images visualized on simulator films. METHODS AND MATERIALS: Depth doses and cross-beam profiles of blocks ranging in width from 1 cm to 10 cm were taken using an automated beam scanning system. These data were then converted to "shadow fields." The results were compared to open fields of the same size using standard methodology. RESULTS: Shadow fields behave quite similarly to small, open fields in terms of x-ray-light field congruence, flatness, symmetry, and penumbra. There is a 2-3 mm rim between the edge of the block and the point at which it becomes nominally effective. The dose at the center of a block, which gives the normalization of the shadow fields, is given by a block transmission factor (BTF), which produces results in excellent agreement with measurements over a wide variety of block sizes and tissue depths. CONCLUSION: The radiation dose under shielding blocks can be considerably higher than expected, and care must be exercised when drawing blocks close to critical structures. The effects of blocks can be described in terms of normalized shadow fields, which behave similar to narrow, open fields, but with a divergence characteristic of their position relative to the radiation source. The normalization value for these fields, which gives the relative dose under the block, can be obtained from a straightforward analytical expression, the BTF.

Lung↗
PubMed1994

Utilization of commercial antisera and flow cytometry in HLA-B27 typing.

The study of large groups of individuals (from reactive arthritis epidemics, for example) for epidemiologic and genetic data has been hampered by the techniques by which HLA typing is performed. Microlymphocytotoxicity is costly not only in materials but also in the time required to perform a given assay and thus does not lend itself to large scale testing. To study such epidemics, in the best way, one must be able to respond as soon as possible after the epidemic is recognized and on a large scale. We thus examined HLA-B27 typing by flow cytometry and commercially available monoclonal antibodies. Two commercially available monoclonal HLA-B27 antibodies were compared. We conclude that the utilization of monospecific HLA-B27 antibodies and flow cytometry allows for the determination of HLA-B27 and HLA-B7 phenotype of a large number of individuals over a short period of time, thereby making the study of a large group both economical and feasible.

Arthritis, Reactive↗
PubMed1994

Serologic testing for reactive arthritis.

The objective of the study was to determine the sensitivity and specificity of quantitative serum antibody response to Salmonella enteritidis lipopolysaccharide (LPS) as a diagnostic test for post-Salmonella reactive arthritis (ReA). In a single food-source outbreak of Salmonella enteritidis, serum was collected from dysenteric individuals with and without ReA at 6, 12, and 24 months post infection. Serum was also collected from control patients with no prior exposure to Salmonella infection. Quantitative measurements of isotypic antibodies to Salmonella enteritidis LPS were performed by an ELISA. Sensitivity and specificity of quantitative isotypic antibody levels over time were plotted on receiver operator characteristic (ROC) curves. Serum IgG and IgA anti-LPS were found to be present in higher levels in the ReA patients than in controls. Using the optimal cutoff of 0.10 selected from an ROC curve, IgG anti-LPS is 88% sensitive and 94% specific, and IgA anti-LPS is 75% sensitive and 100% specific. We conclude that IgA anti-LPS is both sensitive and specific in distinguishing prior exposure to Salmonella LPS in ReA patients compared to unexposed controls.

Antibodies, Bacterial↗
PubMed1994

Secretory immune response and clinical sequelae of Salmonella infection in a point source cohort.

OBJECTIVE: To determine the kinetic isotypic serum and secretory immune response to Salmonella enteritidis in a cohort of individuals exposed to the organism in a single food source outbreak of dysentery. To determine the clinical outcome and immunogenetics of the exposed cohort and to correlate these features with the immune response. METHODS: Following a single point source outbreak of Salmonella enteritidis, a cohort of dysenteric individuals were ascertained using a reactive arthritis screening questionnaire (QUEST). Serum and stimulated saliva samples were obtained at 6, 12, and 24 months following the outbreak of dysentery; examinations were conducted at the same time. Two unexposed control groups were ascertained: (1) general rheumatology clinic patients and (2) well nonarthritic family practice patients. An ELISA to determine quantitative IgA responses to Salmonella enteritidis lipopolysaccharide (LPS) was performed. RESULTS: Eleven of the 84 exposed individuals with dysentery developed reactive arthritis (ReA) of reactive enthesitis (ReE). There was a prolonged salivary IgA anti-LPS response in both the ReA/ReE and DYS (dysentery alone) patients compared with unexposed controls. A ratio of salivary IgA anti-LPS/serum IgA anti-LPS > 1 was associated with a good outcome (remission) of ReA, whereas a ratio < 1 was associated with chronic disease. CONCLUSIONS: There is a more prolonged humoral immune response to Salmonella LPS in exposed individuals than hitherto described. A risk factor in the prolongation of ReA is the inability to mount an appropriate specific salivary (secretory) immune response.

Adolescent↗
PubMed1992

A simple CT aperture emulator for use with a radiotherapy simulator.

Tumor localization in radiation treatment planning often involves the generation of quantitative anatomical data from multiple imaging modalities. It is desirable to take all of the images in the selected treatment position, which is usually decided upon during the initial simulator session. The different scanning modalities are often operated by different staff, at different times and in different locations; thus, it is difficult to ensure consistency in the position of the patient's body, and its documentation, at various times and places. Also, devices such as CT and MR scanners frequently pose restrictions due to their limited apertures. Failure to consider the physical limitations of such scanning equipment at the time of simulation or localization may result in placing the patient in a treatment position which will not fit through the aperture of the CT (or MRI) scanner, or which will result in a clinically important portion of the anatomy being "cut off" in the resulting scans. This can lead to re-simulation of the patient or result in a lack of accurate coordination of simulator and CT scan data. To minimize problems such as these, we have developed a CT Aperture Emulator which can be used at the time of the initial simulation. This is a lightweight "halo" easily attached to the simulator, which mimics the size and shape of the CT aperture. It permits reproducible adjustment of the patient's position, while allowing technologists and physicians to set up the patient with respect to potential CT constraints, in particular with regard to the use of immobilization and support devices. The emulator device also facilitates reproducing a patient's treatment position on the CT scanner. The concept has been found to have additional clinical uses and can be extended to a variety of imaging equipment.

Posture↗
PubMed1992

Nosocomial infection with Clostridium difficile investigated by pyrolysis mass spectrometry.

Fifty-eight isolates of Clostridium difficile from two distinct outbreaks were examined for inter-strain similarity by pyrolysis mass spectrometry (PMS). The first outbreak began on a geriatric acute unit and spread to a long stay geriatric facility. PMS analysis showed that most isolates from both sites were indistinguishable. Isolates obtained in the preceding year from the long stay facility were found to be closely similar to these outbreak isolates. In the second, smaller outbreak on a female medical ward in another general hospital, PMS again showed that a single strain was probably responsible. Representative isolates from these two different outbreaks were shown to be distinct. The ability to compare rapidly large numbers of isolates of C. difficile makes PMS attractive for initial screening in suspected outbreaks, providing important information for outbreak management and allowing conventional typing methods to be concentrated on relevant isolates.

Aged↗
PubMed1992

The cerebral radioprotective effect of alternative barbiturates to pentobarbital.

The potential for normal brain tissue injury is one of the limiting factors in the use of radiotherapy for brain tumors. As attempts to enhance brain tumor radiation sensitivity have been unsuccessful, the use of cerebral radioprotectants provides an attractive alternative. Pentobarbital has recently been shown to be a cerebral radioprotectant in the rodent and primate models of single fraction radiation injury. Because daily high doses of pentobarbital bring certain significant risks, the potential usefulness of alternative barbiturates was explored. Seven groups of rats received 70 Gy of whole-brain-only irradiation in the single fraction. Group 1 was treated while awake. Groups 2, 3, and 4 received pentobarbital, thiopental, and methohexital, respectively. Groups 5, 6, and 7 received increasing doses of phenobarbital. Mean group survival at 30 days after treatment was determined and compared with the survival of animals treated while awake. Thiopental enhanced survival, similar to pentobarbital. Methohexital and phenobarbital were of no radioprotective value. The differences in the hypnotic effects of these barbiturates is based on dissimilar effects on the kinetics of chloride ion channel patency. We propose that these differences also influence their radioprotective properties. Thiopental is a shorter acting alternative to pentobarbital for cerebral radioprotection. Use of it should permit safer and easier investigation of this radioprotective effect in human trials.

Animals↗
PubMed1991

Rapid inter-strain comparison by pyrolysis mass spectrometry in nosocomial infection with Xanthomonas maltophilia.

Seventeen strains of Xanthomonas maltophilia and one strain of Pseudomonas cepacia were examined by pyrolysis mass spectrometry (PYMS). The Xanthomonas strains comprised 11 clinical and environmental isolates from a suspected outbreak of colonization and infection on a heart-lung transplant intensive care unit, two strains from patients elsewhere in the same hospital and four strains from a national reference collection. The single isolate of Pseudomonas cepacia was from a sink in the same affected intensive care unit. A series of discriminant analyses performed on the PYMS-derived data showed that, whereas six strains of Xanthomonas from the respiratory tract, blood and ventilatory equipment of one of the affected patients were indistinguishable, all the other isolates were distinct. The results of PYMS rapid inter-strain comparison were in accord with those of an epidemiological investigation which suggested that the episode was due to unauthorized reuse of disposable nebulizers and not to cross-infection between patients. Pyrolysis mass spectrometry with rapid data analysis is a potentially useful technique for the investigation of nosocomial infections due to organisms such as X. maltophilia.

Bacteriological Techniques↗