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Biomedical subjects

S Kerr

Publications and source records attributed to S Kerr.

At least 19 recordsLinked to original sources
PubMed2004

RSV outbreak in a paediatric intensive care unit.

The Royal Liverpool Children's Hospital-Alder Hey paediatric intensive care unit (PICU) usually has a low rate of nosocomial respiratory syncytial virus (RSV) infection. We report and analyse a major outbreak of nosocomial (acquired) RSV infection on the PICU during a RSV season. All children admitted to the PICU were studied during the six-month winter period 1 October 2002 to 31 March 2002. Nasopharyngeal aspirates were tested using an in vitro enzyme-linked immunoassay (ELISA) membrane test for RSV antigen. PICU-acquired RSV infection was considered to have occurred when a child admitted to the PICU was RSV negative, or from whom no samples were taken as they did not exhibit signs of bronchiolitis, but was RSV positive five or more days after the admission. Fifty-four patients tested RSV positive using the ELISA on the PICU. All the patients were ventilated. Thirty-nine children were RSV positive using the ELISA on admission to the PICU ('imported' cases) and 15 became RSV positive whilst on the PICU ('acquired' cases). The source of the acquired RSV infection accounting for the first peak/outbreak in nosocomial cases were RSV-positive children in isolation cubicles. Acquired cases of RSV infection subsided with reinforcement of traditional methods of barrier precautions. The source of the second peak in nosocomial cases were persistent shedders of RSV. Seventy-three percent (11/15) of the acquired RSV cases had one or more of the following co-morbidities: congenital heart disease, chronic lung disease, airways abnormalities or immunosuppression. Droplet precautions (strict handwashing, use of gloves if handling body fluids, single-use aprons, education) rather than the physical barrier of the cubicle itself played a more important role in curtailing nosocomial spread. Persistent shedders of RSV are an important potential source of nosocomial RSV infection within a PICU. Patients with co-morbidities are at increased risk of nosocomial RSV infection.

Age Distribution↗
PubMed2004

Factors enhancing lycopene production by a new Mycobacterium aurum mutant.

A mutant strain of Mycobacterium aurum was isolated that produced mainly lycopene (>80%) with a total carotenoid content of 1.2 mg g(-1) dry biomass when grown on yeast extract and glucose. Lycopene content of the cells could be significantly increased, up to 7.4 mg g(-1) biomass, by growing the cells at suboptimal initial culture pH (pH 6-6.4) or by using high salt concentration (85 mM NaCl) in the culture medium, although a 25-40% decrease in biomass production occurred in both cases. Highestproductivity (4 mg lycopene l(-1) d(-1)) was obtained by cultivating the cells at pH 6.

Biomass↗
PubMed2004

Patient characteristics and quality of life among a sample of Australian chronic pain clinic attendees.

BACKGROUND: Multidisciplinary chronic pain management programs have proliferated widely in recent decades. The clinical characteristics of patients attending these clinics are becoming the subject of increased research. Recent European data suggests that patients attending these clinics report very low quality of life. AIMS: The present study profiles an Australian population in terms of demographics, clinical characteristics and quality of life, as measured by the Short Form 36 Quality of Life Questionnaire (SF-36). METHODS: Data were collected prospectively from consecutive patients presenting to a multidisciplinary chronic pain clinic at a major Sydney metropolitan teaching-hospital. Cross-sectional analysis of demographic and clinical characteristics and quality of life were then undertaken. RESULTS: Descriptive analysis of demographics and clinical characteristics suggest a patient population group reporting significant pain severity and reduced quality of life. The comparison of SF-36 domain scores between clinic patients and Australian norm values indicates a greatly reduced score on all SF-36 domains for clinic patients. Pain clinic patients reported the most profound effect upon quality of life in the role physical, physical function and social function domains of the SF-36. Stepwise multiple regression indicated impaired coping ability and depressive disability as the most significant correlates of low quality of life. CONCLUSION: Patients who attend chronic pain clinics are likely to report low quality of life with an inability to cope. These findings suggest that future intervention research should explore the impacts of behavioural and self-management interventions. Psychological distress and ability to cope could be used as indices of improvement.

Adult↗
PubMed2004

Screening for novel ENU-induced rhythm, entrainment and activity mutants.

Chemical mutagenesis has provided an opportunity to develop and expand the repertoire of behavioural mutants for gene function studies. With this in mind, we have established a screen in mice for mutations affecting circadian rhythms, entrainment to light and other wheel-running parameters. The screen consists of an assessment of mouse wheel-running activity in a 12:12 h light/dark cycle for 7-10 days followed by assessment in constant darkness for up to 20 days. Responses to light are assessed using two protocols; a 15 minute light pulse given at circadian time 16 on the tenth day in constant darkness and an additional 12 h of light upon transition from light/dark conditions to constant darkness. To date, approximately 1300 progeny of chemically mutagenised mice have been screened. Computer-aided assessment of wheel-running parameters has helped in identifying abnormal phenotypes in approximately 5% of all animals screened. Inheritance testing of mice with abnormal phenotypes has confirmed the number of robustly inherited mutant phenotypes to be 1% of the total screened. Confirmed mutants including those affecting free-running period, light-responsiveness and wheel-running endurance have been identified. Thus far, low-resolution map positions have been established for four mutants by completing genome scans in backcross progeny. Mutant loci do not correspond with those previously associated with wheel-running behaviour. This result confirms that phenotype-driven approaches such as this should continue to provide material for mammalian gene function studies.

Animals↗
PubMed2002

Complex regional pain syndrome post mastectomy.

Complex regional pain syndrome includes the previously termed condition reflex sympathetic dystrophy. It is a chronic pain disorder diagnosed on the basis of symptoms and skin changes and is known to have a psychological element. It is a rare complication after surgery, especially mastectomy. We present two females who developed this syndrome after undergoing mastectomy for chronic mastalgia. These cases demonstrate that amputation of an organ for chronic pain can result in reflex sympathetic dystrophy developing in a nearby limb.

Adult↗
PubMed2001

Haematological response to parvovirus B19 infection in homozygous sickle-cell disease.

Infection with human parvovirus B19 is known to cause aplastic crises in patients with homozygous sickle-cell disease. We studied the haematological consequences of parvovirus B19 infection in 280 such patients who had been followed up from birth in Jamaica. Evidence of seroconversion was routinely sought with a baculovirus-based, enzyme immunoassay in serum samples taken during aplastic crises and in all stored annual serum samples. 70% of patients had seroconverted by age 20 years; of 177 infections, haematological change was typical of aplastic crises in 118 (67%), minor in 16 (9%), and not discernible in 43 (24%). This assay increased the detection of unsuspected seroconversion-an observation important in planning a strategy for parvovirus B19 immunisation.

Adolescent↗
PubMed2001

Identification, characterization and leucocyte expression of Siglec-10, a novel human sialic acid-binding receptor.

Here we characterize Siglec-10 as a new member of the Siglec family of sialic acid-binding Ig-like lectins. A full-length cDNA was isolated from a human spleen library and the corresponding gene identified. Siglec-10 is predicted to contain five extracellular Ig-like domains and a cytoplasmic tail containing three putative tyrosine-based signalling motifs. Siglec-10 exhibited a high degree of sequence similarity to CD33-related Siglecs and mapped to the same region, on chromosome 19q13.3. The expressed protein was able to mediate sialic acid-dependent binding to human erythrocytes and soluble sialoglycoconjugates. Using specific antibodies, Siglec-10 was detected on subsets of human leucocytes including eosinophils, monocytes and a minor population of natural killer-like cells. The molecular properties and expression pattern suggest that Siglec-10 may function as an inhibitory receptor within the innate immune system.

Amino Acid Sequence↗
PubMed2001

Torsional properties of commercial nickel-titanium wires during activation and deactivation.

This study evaluated torsional moments on activation and deactivation in commercial, nickel-titanium wires that are intended for use in the initial phases of orthodontic treatment. Nine commercial, rectangular nickel-titanium wires (0.017 x 0.025 in) were tested in torsion. One wire was conventional nickel-titanium, and the others were superelastic nickel-titanium wires. The specimens were tested in a torsiometer for rotations between 10 and 40 degrees in activation and deactivation. Wires E27, RF and R had the highest moments during activation and deactivation, without evidence of the plateau typical of the superelastic effect. Plateaus of constant moment were observed for wires C27, C35, E35, MO, NS, and NI. Torsional moments varied among superelastic nickel-titanium wires, even with wires that had the same transition temperature range. Some superelastic wires had torsional moments that were comparable with conventional nickel-titanium wires.

Dental Alloys↗
PubMed2001

Force-deflection properties of superelastic nickel-titanium archwires.

This in vitro study compared the force-deflection behavior of 8 superelastic nickel-titanium orthodontic wires (0.017 x 0.025 in) under controlled moment and temperature. To simulate leveling a lateral incisor, brackets and first molar tubes without tip and angulation were used. The wires (n = 5) were ligated into stainless steel brackets attached to a plastic jig to simulate a mandibular arch. A testing machine (Instron) applied deflections of 0.2 to 2.0 mm at 35 degrees C in the lateral incisor area. Force-deflection diagrams were determined from the passive position to an activation of 2 mm and then during deactivation. Forces on deactivation at a deflection of 1 mm were compared by analysis of variance. Significant differences (P < .05) in forces were observed among wires. All wires exhibited superelastic behavior, but in stratified loading levels.

Analysis of Variance↗
PubMed2001

Quinolinic acid is produced by macrophages stimulated by platelet activating factor, Nef and Tat.

Activated macrophages produce quinolinic acid (QUIN), a neurotoxin, in several inflammatory brain diseases including AIDS dementia complex. We hypothesized that IL1-beta, IL6, transforming growth factor (TGF-beta2 and platelet activating factor could increase macrophage QUIN production. And that the HIV-1 proteins Nef, Tat and gp41 may also increase synthesis of QUIN by macrophages. At 72 h there were significant increases in QUIN production in the cells stimulated with PAF (914 +/- 50 nM) and Nef (2781 +/- 162 nM), with somewhat less production by Tat stimulation (645 +/- 240 nM). The increases in QUIN production approximated in vitro concentrations of QUIN shown to be neurotoxic and correlated closely with indoleamine 2,3-dioxygenase induction. IL1-beta, IL6, TGF-beta2 and gp41 stimulation produced no significant increase in QUIN production. These results suggest that some of the neurotoxicity of PAF, nef and tat may be mediated by QUIN.

AIDS Dementia Complex↗
PubMed2001

The radiographer and role expansion in nuclear medicine.

With the introduction and wide application of Clinical Governance to all clinical areas, all healthcare professionals including radiographers/technologists working in Nuclear Medicine need to gain skills required for implementation. New professional and legal obligations demand that relevant expertise is developed. This article examines the potential for role expansion of radiographers/technologists in Nuclear Medicine with emphasis on the training and development aspects. The key areas addressed include clinical audit, risk management, research, management and continuing professional development.

Allied Health Personnel↗
PubMed2000

Detection of parvovirus B19 IgM by antibody capture enzyme immunoassay: receiver operating characteristic analysis.

Parvovirus B19 infection can cause severe effects in high-risk groups including pregnant women and immunocompromised individuals. Although serological detection of B19 infection is commonplace, minimal information is available on the absolute performance characteristics of various tests for the detection of B19 IgM. The performance of the first parvovirus B19 IgM enzyme immunoassay to be cleared by the US Food and Drug Administration (FDA) is described. The immunoassay cut-off has been established using receiver operating characteristic (ROC) analysis giving a sensitivity and specificity of detection of 89.1 and 99.4%, respectively. No cross-reactivity is observed with rubella or other viral disease IgM which cause similar symptomologies to parvovirus B19. Multi-site reproducibility studies have shown high immunoassay reproducibility with detection rates (observed/expected result) of 100% for nonreactive specimens (N=324) and strongly reactive (N=403), respectively. Immunoassay reproducibility ranged from 11.76 to 17. 46% coefficient of variation for all reactive specimens tested (N=12) whereby each specimen was assayed a total of 81 times. Parvovirus B19 IgM seroprevalence of 1% was observed in a US blood donor population (N=399). In the absence of international performance criteria, this study will be of major benefit to the clinical virologist in assessing immunoassay reliability for the detection of recent infection with parvovirus B19.

Antibodies, Viral↗
PubMed1999

Features of acute rejection that increase risk for chronic rejection.

BACKGROUND: Acute rejection (AR) has been shown to be a significant risk factor for chronic rejection (CR) in kidney transplant recipients, yet many recipients with AR do not progress to CR. The purpose of this study was to determine if certain AR episodes are associated with a worse prognosis. METHODS: The study group consisted of 279 kidney transplant recipients, all treated for a single episode of biopsy-proven AR. All AR episodes were initially treated with steroids; steroid-resistant rejection was managed with an antibody preparation. RESULTS: First, by univariate techniques, we determined the clinical impact of severity of AR (as estimated by delta creatinine [dCr], defined as the change in baseline serum creatinine level 6 weeks after AR treatment) on two different endpoints--biopsy-proven CR and graft survival. Irrespective of 6-week dCr, all recipients with AR had a significantly increased risk of CR vs. those with no AR (P<0.01). Recipients with dCr between 0.5 and 1.0 mg/dl had a significantly higher incidence of CR vs. those with dCr <0.5 mg/dl (P<0.05), but a significantly lower incidence vs. those with dCr >1.0 mg/dl (P<0.05). We then performed multivariate analysis. We used severity of AR in addition to other variables (e.g., timing of AR, donor age) to determine which factors were most associated with risk for CR and graft loss. Risk for CR increased with AR episodes occurring >6 months after transplant (relative risk [RR] = 3.8, P = 0.005); with moderate or severe (vs. mild) AR episodes (RR = 2.7, P = 0.05); and with dCr >0.5 mg(dl (vs. <0.5 mg/dl) at 6 weeks after AR treatment (RR = 2.3, P = 0.1). Findings were similar when graft survival (death-censored) was the endpoint instead of CR. CONCLUSIONS: All AR episodes are associated with some increase in the risk for CR. But AR episodes occurring >6 months after transplant and those of increased severity (as assessed qualitatively by histologic grading and quantitatively by dCr) confer the greatest risk. Recipients with these risk factors could be targeted with measures to decrease their risk for CR, including trials of novel immunosuppressive regimens.

Acute Disease↗
PubMed1999

Undenatured parvovirus B19 antigens are essential for the accurate detection of parvovirus B19 IgG.

Recombinant versions of parvovirus B19 capsid proteins VP1 and VP2 are used for immunodiagnostic assays for detection of antiviral antibodies. The immune response to B19 is characterized by a gradual loss of antibodies directed against linear epitopes of VP2. A similar occurrence for antibodies raised against VP1 protein would represent a limitation to serological assays incorporating denatured versions of either viral antigen. Four detection systems for B19 Ig detection have been developed, including an IgG enzyme immunoassay (EIA) based on undenatured VP2, an immunofluorescence assay (IFA) based on undenatured VP1, a Western blot assay incorporating denatured VP1 and VP2, and an alternative blot system using denatured VP1 but undenatured VP2. Specimens (n=108) were tested by all four systems and identical results were obtained by EIA, IFA, and alternative blot systems, whereby 75/108 (69%) were B19 IgG-positive. Twelve B19 IgG-positive specimens, representing 16% (12/75) of the confirmed positives, did not react to either viral antigens when tested by Western blot. It is concluded that these sera do not react with linear epitopes of VP1 and VP2 antigens. Eighty-five different specimens, which had previously been shown to be both B19 IgM- and IgG-positive by EIA and IFA, were positive by B19 IgM and IgG Western blot. In the IgG Western blot assay, 69 reacted with both VP1 and VP2 and 16 with VP1 only. It is concluded that there is a requirement for at least one undenatured antigen for the immunological detection of B19 IgG.

Animals↗
PubMed1999

Superoxide anion production is increased in a model of genetic hypertension: role of the endothelium.

The hypothesis that the decreased nitric oxide (NO) availability observed in spontaneously hypertensive stroke-prone rats (SHRSP) is due to excess superoxide (O2-) was examined. O2- generation, measured by lucigenin chemiluminescence, was studied in 12- to 16-week male and female Wistar-Kyoto rats (WKY) and SHRSP. In addition, expression of the gene encoding endothelial NO synthase, the enzyme involved in NO generation, was investigated. O2- generation was increased in male and female SHRSP (4.11+/-0.24 and 3. 84+/-0.28 nmol O2-. min-1. mg-1 respectively) compared with their WKY counterparts and was significantly higher in male than female WKY (1.22+/-0.08 in males and 0.8+/-0.08 nmol O2-. min-1. mg-1 respectively) (SHRSP versus WKY P<0.0001, 95% CI -3.39, -2.51; male versus female WKY P=0.0029, 95% CI -0.67, -0.17). Removal of the endothelium by rubbing or addition of NO synthase inhibitors attenuated O2- generation in SHRSP but not WKY. In males, removal of the endothelium reduced O2- generation from 3.86+/-0.12 to 1.35+/-0. 08 nmol. min-1. mg-1 (P<0.0001, 95% CI 2.29, 2.81), whereas addition of L-NAME caused a reduction from 4.13+/-0.17 to 1.32+/-0.16 nmol. min-1. mg-1 (P<0.0001, 95% CI 2.36, 2.83). Similar reductions were observed in females. L-arginine had no significant effect, but tetrahydrobiopterin significantly decreased O2- generation in SHRSP from 4.04+/-0.11 to 2.36+/-0.40 nmol. min-1. mg-1 (P=0.0026, 95% CI 0.89, 2.44). Endothelial NO synthase mRNA expression was significantly greater in SHRSP than in WKY and in WKY males than in WKY females. These results show that O2- generation is increased in SHRSP and that the tissue and enzymatic sources of this excess O2- appear to be the endothelium and eNOS, respectively. The increase in O2- generation could explain the decreased availability of basal NO observed in this model of genetic hypertension.

Animals↗