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Biomedical subjects

D Chinn

Publications and source records attributed to D Chinn.

13 recordsLinked to original sources
PubMed2004

The relationship between lean body mass and bone mineral content in paediatric health and disease.

INTRODUCTION: The correct interpretation of DXA data is critical to the diagnosis and management of children with suspected bone disease. This study examines the various influences on bone mineral content (BMC), as measured by dual-energy X-ray absorptiometry (DXA). MATERIALS AND METHODS: Six hundred and forty-six healthy school children and forty-three children with chronic diseases, aged 5-18 years, had their lumbar spine and whole body measured using a Lunar DPX-L DXA scanner. RESULTS: Stepwise linear regression identified lean body mass (LBM) as the strongest single predictor of BMC in the lumbar spine and the total body. A significant gender difference was observed in the relationship between BMC and LBM with girls having significantly more bone per unit LBM from 9 years of age in the spine and 13 years of age in the total body. To investigate the relationship between LBM and BMC in children with chronic disease, a two-stage algorithm based upon calculation of Z scores from the normative data was applied. Stage 1 assessed LBM for height and stage 2 assessed BMC for LBM. Ten children with spinal muscular atrophy had a mean LBM for height Z score of -1.8(1.4) but a mean BMC for LBM Z score of 1.2(1.3) indicating their primary abnormality was reduced muscle mass (sarcopenia) with no evidence of osteopenia. In contrast, 21 children with osteogenesis imperfecta had a mean LBM for height Z score of 0.4(1.7) but a mean BMC for LBM Z score of -2.5(1.8) indicating normal LBM for size but significantly reduced BMC for LBM (i.e. osteopenia) confirming a primary bone abnormality. A third group consisting of 12 children with low trauma fractures demonstrated little evidence of sarcopenia [mean LBM for height Z score -1.1(2.1)] but significant osteopenia [mean BMC for LBM Z score -1.9(1.5)]. CONCLUSION: The results from this study demonstrate how the relationship between height and lean body mass, and lean body mass and bone mineral content can be a useful method of diagnosing osteoporosis in children and how the relationships can be used to identify if the primary abnormality is in muscle or bone.

Adolescent↗
PubMed2002

Long-term aminosalicylate therapy is under-used in patients with ulcerative colitis: a cross-sectional survey.

BACKGROUND: There is evidence from case-control studies that aminosalicylate drugs can reduce colorectal cancer risk by 75-81% in patients with ulcerative colitis. Patients may fail to comply with long-term therapies, however, or may have been advised to discontinue treatment once in remission. AIM: To describe the usage of long-term aminosalicylate therapy in patients with ulcerative colitis. METHODS: A cross-sectional study was performed using data extracted from general practitioner clinical records on demographic features, extent and duration of disease, use of aminosalicylate therapy and specialist care. RESULTS: Three hundred and sixty-three people had ulcerative colitis and no history of colorectal surgery. Ninety-five of 175 (54%) patients with proctitis, 78 of 123 (63%) patients with left-sided colitis and 28 of 45 (62%) patients with extensive colitis were currently taking an aminosalicylate drug. Those doing so were more likely to be under specialist care than to be definitely or possibly discharged (odds ratio, 4.9; 95% confidence interval, 2.9-8.4). The likelihood of current aminosalicylate therapy was not related to gender or the extent of disease, but was negatively related to the duration of disease. CONCLUSIONS: A substantial minority of patients with ulcerative colitis does not take long-term aminosalicylate therapy. Those who do are more likely to be under specialist care, to be older or to have disease of shorter duration.

Adult↗
PubMed2002

Is clinical practice variability the major reason for differences in pathology requesting patterns in general practice?

AIMS: To examine whether variations in pathology test requesting between different general practices can be accounted for by sociodemographic or other descriptive indicators of the practice. METHOD: This was a comparative analysis of requesting patterns across a range of pathology tests representing 95% of those requested in general practice, in 22 general practices in a single district, serving a population of 165 000. Spearman correlation coefficients were calculated and both the top and bottom fifths of activity were displayed graphically to detect trends at the extremes of the ranges. RESULTS: The proportion of women of childbearing age, median practice Townsend scores, or the existence of specialist miniclinics within the practice did not have a demonstrable impact on requesting patterns. A weak correlation was found between the proportion of elderly patients and creatinine/electrolyte testing but not for the other two tests examined for this patient group. CONCLUSIONS: The large differences observed in general practice pathology requesting probably result mostly from individual variation in clinical practice and are therefore potentially amenable to change.

Adolescent↗
PubMed2000

Benchmarking general practice use of pathology services: a model for monitoring change.

AIMS: To identify a model to assess general practitioner use of pathology services that could be applied to assess specific interventions designed to promote best practice. METHODS: A database containing standardised requesting data for 22 general practices was constructed. The database contained 28 tests covering 95% of general practitioner activity, distributed across pathology, and it was evaluated during two sequential six month periods. A comparison of ranks of requesting activity between different time periods was undertaken by calculating Pearson rank correlation coefficients. Requesting numbers were also adjusted for patients' age and sex distributions within the 22 practices for a sample of three high volume tests. The effects of distributing requesting guidelines and details of requesting activity were assessed during two sequential three month periods. RESULTS: Requesting activity was extremely stable during the two baseline periods for most test (r > 0.80 for 20 of the 28 tests). Several less discriminatory tests were identified. Age and sex adjustment had minimal impact on the ranks of requesting activity. Requesting activity during the two three month periods after distributing guidelines and comparative details of individual requesting activity showed little change (overall correlation coefficient, 0.844 between baseline and intervention periods). CONCLUSIONS: Ranking general practitioners requesting activity adjusted for practice list size provides a reproducible means of measuring requesting activity for most pathology tests performed in general practice. Activity was not influenced by age or sex of patients on the practice list. Distributing requesting guidelines and individual requesting activity on their own do not have any measurable impact on requesting activity. More innovative (possibly multiple) interventions might be required to influence general practitioner requesting practice.

Age Factors↗
PubMed2000

Therapeutic Strategies for Localized Prostate Cancer II: Perineal Prostatectomy, X-Rays, Protons, Neutrons, and Combination Brachytherapy.

Application of improved imaging, diagnostic, and computer techniques is beginning to have an impact on the management of localized prostate cancer. It is possible to perform a range of surgical and radiation procedures with less morbidity than in the past. The changes in therapy for patients with localized disease derive from better knowledge of anatomy for invasive procedures and optimization of virtual planning for noninvasive methods. Perineal prostatectomy and combinations of beam and seed radiation offer both patient and physician reasonable therapeutic options.

Journal Article↗
PubMed1999

The Newcastle exercise project: a randomised controlled trial of methods to promote physical activity in primary care.

OBJECTIVE: To evaluate the effectiveness of combinations of three methods to promote physical activity. DESIGN: Randomised controlled trial. Baseline assessment with post-intervention follow up at 12 weeks and 1 year. SETTING: One urban general practice, 1995-7. PARTICIPANTS: 523 adults aged 40 to 64 years, randomised to four intervention groups and a control group. INTERVENTIONS: Brief (one interview) or intensive (six interviews over 12 weeks) motivational interviewing based on the stages of change model of behaviour change, with or without financial incentive (30 vouchers entitling free access to leisure facilities). MAIN OUTCOME MEASURES: Physical activity score; sessions of moderate and vigorous activity in the preceding four weeks. RESULTS: Response rate was 81% at 12 weeks and 85% at one year. More participants in the intervention group reported increased physical activity scores at 12 weeks than controls (38% v 16%, difference 22%, 95% confidence interval for difference 13% to 32%), with a 55% increase observed in those offered six interviews plus vouchers. Vigorous activity increased in 29% of intervention participants and 11% of controls (difference 18%, 10% to 26%), but differences between the intervention groups were not significant. Short term increases in activity were not sustained, regardless of intensity of intervention. CONCLUSIONS: The most effective intervention for promoting adoption of exercise was the most intensive. Even this did not promote long term adherence to exercise. Brief interventions promoting physical activity that are used by many schemes in the United Kingdom are of questionable effectiveness.

Adult↗
PubMed1996

Activation antigen expression on human T cells. I. Analysis by two-colour flow cytometry of umbilical cord blood, adult blood and lymphoid tissue.

Activation antigens (actags) were detected on T cells at low levels of intensity by carefully defining negative cells with a panel of control antibodies. The mean percentage of blood T cells from healthy volunteers that expressed actags were 22% (CD25), 54% (CD26), 38% (CD38), 12% (CD54), 6% (CD69) and 21% (HLA-DR). The variability of actag expression detected by this sensitive method was determined on healthy volunteers by repeated estimation over a year. The percentage of T cells expressing CD25 and CD26 varied no more than repeated estimation of the CD4 T cell subset, whereas other actags showed greater variability. The antigen density of these actags on T cells was determined in relation to CD4 antigen density, and for most actags ranged from 10% to 75% of the level of CD4 antigen density except for CD7 and HLA-DR, which could exceed that of CD4. Different degrees of actag expression characterized T cells from different blood and lymphoid tissues. CD26, CD38 and CD45RA were universally expressed in cord blood at higher antigen density than adult blood. This immature pattern was consistent with recent thymic emigration. CD25, CD45RO, CD54 and HLA-DR progressively increased from cord blood through adult blood to lymphoid tissues, consistent with antigen-driven activation, whereas CD26 and CD45RA decreased. CD69, a very early activation antigen, abruptly increased in lymphoid tissue, exceeding CD25 by two-to-three-fold and suggesting a pre-activation state that may not involve commitment to antigen-driven proliferation. CD7 and CD38 expression was higher in cord blood and lymphoid tissue than in adult blood, indicating both an antigen-independent and -dependent up-regulation.

Adult↗
PubMed1978

A survey of drug use among probationers in the Los Angeles area in 1976.

The results are presented from the analysis of 10,000 urine specimens from Los Angeles County probationers in early 1976 for the following drugs: amphetamine, methamphetamine, allylbarbital, amobarbital, butabarbital, pentobarbital, phenobarbital, secobarbital, morphine, codeine, methadone, primary metabolite of methadone, cocaine, benzoylecgonine, propoxyphene, norpropoxyphene, methaqualone, and phencyclidine. Over 27% of the urine samples analyzed were positive for at least one drug. Opiates were found to be the most widely used drugs, but multiple drug use was also quite common.

California↗