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Biomedical subjects

R Hanson

Publications and source records attributed to R Hanson.

At least 19 recordsLinked to original sources
PubMed2000

Association of dopamine D2 receptor polymorphisms Ser311Cys and TaqIA with obesity or type 2 diabetes mellitus in Pima Indians.

OBJECTIVES: To investigate whether (a) variants within the dopamine D2 receptor gene (DRD2) are associated with obesity and type 2 diabetes in Pima Indians, and (b) whether variation in this gene could be responsible for previously observed linkage to these phenotypes, at chromosome location 11q23-24, in this population. DESIGN: Two single nucleotide polymorphisms (SNPs), Ser311Cys and TaqIA, within the DRD2 gene were genotyped by allelic discrimination PCR in subjects who had provided evidence of linkage to diabetes and obesity in an autosome-wide scan. SUBJECTS: A total of 1,187 subjects were genotyped, including 947 full heritage Pima Indians (80%). Descriptive statistics for all subjects analyzed, for whom clinical data were available, were (mean+/-s.d.): age at time of last exam = 41 +/- 15 y; birth year=1950 +/- 14; age-sex-adjusted body mass index (BMI; adjusted to a mean age of 35y)=36 +/- 8kg/m2; male = 44%; diabetic = 57%. For full heritage Pimas only: age = 43 +/- 15 y; birth year = 1948 +/- 14; sex- age-adjusted BMI = 36 +/- 8 kg/m2; male = 43%; diabetic = 59%. RESULTS: Neither polymorphism was significantly associated with diabetes in full heritage Pimas. Individuals with a 'CG' genotype at the Ser311Cys SNP had a higher BMI than those with a 'CC' genotype (36.7 vs 35.5 kg/m2, P= 0.04). Linkage analysis of BMI, adjusted for either polymorphism, resulted in LOD scores that were similar to those obtained without adjustment. CONCLUSION: Heterozygotes at the Ser311Cys DRD2 polymorphism had a slightly higher BMI than homozygotes, however neither the Ser311Cys nor the TaqIA polymorphism accounted for the linkage with BMI on chromosome 11 in Pima Indians.

Adult↗
PubMed2000

Parental use of a paediatric emergency department as an ambulatory care service.

OBJECTIVE: This qualitative study explored the parental attitudes, perceptions and beliefs that play a role in the use of a tertiary paediatric emergency department (PED) when a child has a non-urgent illness. METHOD: Semi-structured, in-depth interviews of 25 parents of children with non-urgent illnesses were conducted in the waiting room of a tertiary PED in Western Sydney in 1998. Inductive analysis was used to identify dominant themes. RESULTS: Parents used their own system of triage to choose the appropriate service for their sick child. The perceived expertise of the tertiary PED, access and parental expectations all appeared to be major factors in parental use of a PED. CONCLUSIONS: The parental choice to attend a PED is a dynamic, complex and unique process and the parental views that underpin this process often diverge from those of health professionals about the most 'appropriate' use of a PED. IMPLICATIONS: A clearer understanding by health professionals of the factors influencing parental choice will promote more effective collaboration with parents and ultimately assist in the decision on the best management option for sick children.

Adolescent↗
PubMed1999

Upstream stimulatory factor 1 regulates osteopontin expression in smooth muscle cells.

Vascular smooth muscle cells (SMCs) undergo a dramatic phenotypic transition in response to injury and ex vivo culture that includes enhanced proliferation, migration, matrix deposition, and alterations in gene expression. Osteopontin is a good marker for the injury-induced SMC phenotypic state in vivo and in vitro. To identify transcription factors that might control the regulation of osteopontin expression, we investigated cultured vascular SMCs that express high and low levels of osteopontin. Using nuclear run-on assays, mRNA stability studies, and deletion analysis, we demonstrate that regulation of osteopontin steady-state mRNA levels in SMCs occurs at the transcriptional level. Transient transfection and gel-shift analyses of osteopontin promoter indicated that a region between -123 and +66 was involved in the expression of osteopontin. Supershift EMSAs identified the bHLH-leucine zipper transcription factor upstream stimulatory factor-1 (USF1) as the protein binding to this sequence. Finally, we show that USF1 protein is induced in vivo within 24 h of balloon angioplasty of rat carotids coordinately with osteopontin induction. These data suggest that USF1 governs expression of osteopontin in cultured vascular SMCs and might contribute to initial osteopontin expression observed post carotid injury and in vascular pathologies in vivo.

Aging↗
PubMed1999

Validation of a predictive model for asthma admission in children: how accurate is it for predicting admissions?

We studied 364 index presentations to the Emergency Department of a children's hospital with a diagnosis of asthma. The admission rate for this group of children was about 31%. We developed a parsimonious multiple logistic regression model to predict asthma hospital admission based on asthma severity indicators. We then evaluated the model's predictive ability using two methods of cross-validation, using the same sample that was used for the predictive model, and using data from a split sample. The logistic regression model had a predictive accuracy of 90% (95% confidence interval 85-95%). The sensitivity and specificity were 86% and 88%, respectively. Cross-validation models confirmed that the predictive ability of the model was stable. In studies with limited sample sizes, it is possible to validate a model without setting aside a split sample for cross-validation.

Acute Disease↗
PubMed1998

Casemix funding in Australia.

Casemix funding for hospitals with the use of diagnosis-related groups (DRGs), which organise patients' conditions into similar clinical categories with similar costs, was introduced in Australia five years ago. It has been applied in different ways and to a greater or lesser extent in different Australian States. Only Victoria and South Australia have implemented casemix funding across all healthcare services. Attempts have been made to formally evaluate its impact, but they have not met the required scientific standards in controlling for confounding factors. Casemix funding remains a much-discussed issue. In this Debate, Braithwaite and Hindle take a contrary position, largely to stimulate policy debate; Phelan defends the casemix concept and advocates retaining its best features; and Hanson adds a plea for consumer input.

Diagnosis-Related Groups↗
PubMed1998

Carbon Monoxide, Nitric Oxide, and Nitrogen Dioxide Levels in Gas Ovens Related to Surface Pinking of Cooked Beef and Turkey.

Carbon monoxide (CO) and total nitrogen oxide (NO(x)()) levels were monitored during meat cookery with a standard Ovenpak and a new ultralow-NO(x)() (ULN) cyclonic gas burner. With the standard burner, CO varied from 103 to 152 ppm, NO(x)() was 1.3-10.7 ppm, and surface pinking was observed on both beef and turkey. The ULN burner at optimal efficiency produced only 6.7 ppm of CO and 1 ppm of NO(x)(), insufficient to cause surface pinking. To determine the relative contribution of CO and NO(x)() to pinking, trials were also conducted in an electric oven with various pure gases. Pinking was not observed with up to 149 ppm of CO or 5 ppm of NO. However, as little as 0.4 ppm of nitrogen dioxide (NO(2)) caused pinking of turkey rolls. Beef roasts were pink at >2.5 ppm of NO(2). Thus, pinking previously attributed to CO and NO in gas ovens is instead due to NO(2), which has much greater reactivity than NO with moisture at meat surfaces.

Journal Article↗
PubMed1998

Familial aggregation of osteoarthritis: data from the Baltimore Longitudinal Study on Aging.

OBJECTIVE: To evaluate the familial aggregation of osteoarthritis (OA) in a cohort of healthy volunteers drawn from a community setting. METHODS: Hand radiographs obtained between 1978 and 1991 and bilateral standing knee radiographs obtained between 1984 and 1991 were read for changes of OA, using Kellgren-Lawrence (K-L) scales. The hand sites were distal interphalangeal (DIP) joints, proximal interphalangeal (PIP) joints, and first carpometacarpal (CMC1) joints. For each joint group, the presence of OA in at least 1 joint in a joint group, the number of affected digits in each joint group, and the sum of the K-L grade across all joints were analyzed. Polyarticular OA was recorded if there were OA findings in 2 of 3 hand joint groups plus 1 or both knees. Data from 167 families with hand radiographs, 157 families with knee radiographs, and 148 families with both hand and knee radiographs were analyzed for sib-sib correlations. RESULTS: After adjustment for age, sex, and body mass index, clinically relevant sib-sib common correlations were found for OA of the DIP, PIP, and CMC1 joints, for OA at 2 or 3 hand sites, and for polyarticular OA (r = 0.33-0.81) when OA was defined according to the number of affected joints or as the sum of the K-L grade across all joints. CONCLUSION: These results from a cohort of volunteers drawn from a community setting and ascertained without regard to OA status demonstrate familial aggregation of OA and contribute to the evidence for heritability of OA.

Adult↗
PubMed1998

Admission rates as an indicator of the prevalence of severe asthma in the community.

BACKGROUND: A reliable indicator of the prevalence of severe asthma in the community is needed to monitor population-based asthma control strategies. We examined the potential use of asthma admissions to hospital as such an indicator. METHODS: We recruited subjects from the Emergency Department (ED) of a children's hospital. The attending doctor completed the 'physician questionnaire' which included questions on the patient's asthma severity and interval severity/chronicity of asthma. The parent/guardian completed the 'parent questionnaire'. It included questions on demography, asthma knowledge and attitudes, asthma history and social support. We performed univariate and multiple logistic regression to determine predictors for hospital admission. RESULTS: Interval severity of asthma, pre-treatment severity of wheeze and low post-treatment pulse oximetry best predicted whether children presenting with asthma were admitted. Demographic variables, factors associated with access to health services and factors related to the asthma history and management were not significant predictors of admission. DISCUSSION: At the population level, it may be possible to utilise routine hospital admission rates as an indicator of the prevalence of severe asthma in the community, especially within the context of monitoring trends in asthma prevalence. Our study was conducted in a metropolitan tertiary paediatric hospital. The reliability of hospital admission rates as indicators of the prevalence of severe asthma in other hospital settings, in different population groups and over time remains to be established.

Adolescent↗
PubMed1998

Renal Hemodynamics: Longitudinal Study from the Late Fetal Life to One Year of Age

>Objective: To evaluate longitudinally the renal circulation from late gestation to the first year of life in order to understand fundamental changes within this vascular bed as the fetus adapts to major circulatory changes occurring during this time period.Methods: Sixteen healthy human fetuses were studied during the last trimester of the pregnancy, within 2 days of birth, at 6 weeks, at 6 months, and at 1 year. Using noninvasive color pulsed Doppler, blood flow velocities of the renal artery, the tricuspid and mitral valves in the fetus, and in the ascending aorta in the newborn/infants were obtained at each study. Diameters of these respective areas were also obtained. Total cardiac output and renal blood flow were calculated using the time velocity integral, the area of the structure of interest, and heart rate.Results: 1) Renal artery dimensions, time velocity integral, peak flow velocity, systolic to diastolic ratio, absolute volume blood flow (RVBF) were all significantly correlated with advancing gestational age; 2) RVBF relative to body weight and percent RVBF were not.Conclusions: In spite of an overall increase in renal blood flow, flow to the kidney appears to be constant during the time period of this study. Most of the "maturational" changes that occur within this vascular bed appear to be related to changes within the vascular resistance and the renal artery diameter.

Journal Article↗
PubMed1998

Is asthma documentation improved by computer-facilitated data entry?

The documentation of acute asthma in written medical records was compared with data entered into a Computer-Assisted Triage System (CATS) in 104 children who presented to the emergency department and subsequently admitted to the Royal Alexandra Hospital for Children, Sydney. A total of 65 items in 5 categories were analysed and satisfactory documentation was defined as the recording of a specific item in more than 80% of records (written or electronic). Satisfactory documentation was observed for all 6 items in visit details and 9 out of 10 items in triage details for both recording systems. Nursing observations were better documented in the medical record than in CATS (87 vs 25%; kappa = 0.63). Documentation of medical details was also worse in CATS (75 vs 25%; kappa = 0.24) and the documentation of asthma severity was poor in both systems (31 vs 0%; kappa = 0.31). Attempts to improve asthma documentation through the development of a computerized medical record have highlighted further barriers to documentation.

Asthma↗
PubMed1998

10 questions about Lyme neuroborreliosis.

The diagnosis of Lyme neuroborreliosis requires a high index of suspicion and chronological correlation of the clinical findings and laboratory data. The limitations of serologic tests must be understood. Cerebrospinal fluid anti-Borrelia burgdorferi antibody index is currently the best indicator of Lyme neuroborreliosis.

Antibodies, Bacterial↗
PubMed1997

Defects in yolk sac hematopoiesis in Mll-null embryos.

Translocations involving the mixed lineage leukemia gene (MLL), the human homolog of the Drosophila gene trithorax, are one of the most common genetic alterations in human acute leukemias. Each translocation involving MLL results in loss of one functional copy of MLL and the generation of a chimeric fusion protein with potential dominant negative or neomorphic activity. Mll is a positive regulator of Hox genes, which have been implicated in both axial skeleton patterning and hematopoietic development. Previous studies indicated that Hox gene expression is altered in Mll heterozygous (+/-) and homozygous (-/-) deficient mice. To study the role of Mll in hematopoiesis and to obtain insights into leukemogenesis, we have examined the effects of haplo-insufficiency or absence of Mll by in vitro differentiation of Mll +/+, +/-, and -/- yolk sac progenitor cells. Mll -/- colonies were fewer in number, took longer to develop, and contained fewer cells than their wild-type and heterozygous counterparts. Formation of colony-forming unit-granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM), colony-forming unit-macrophage (CFU-M), and burst-forming unit-erythroid (BFU-E) was markedly decreased in Mll -/- cultures, while numbers of colony-forming unit-erythroid (CFU-E), colony-forming unit-granulocyte (CFU-G), and colony-forming unit-granulocyte macrophage (CFU-GM) were essentially unaffected. Despite the decreased numbers of colonies present, Mll -/- cultures showed all cell types without morphologic evidence of maturation arrest. These studies indicate that Mll is required for normal numbers of hematopoietic progenitors and their proper differentiation, especially along the myeloid and macrophage pathways.

Animals↗
PubMed1996

M-mode echocardiographic evaluation of fetal and infant hearts: longitudinal follow-up study from intrauterine life to year one.

OBJECTIVE: Our purpose was to evaluate cardiac variables, including right and left end-diastolic and end-systolic dimensions by use of M-mode echocardiography during fetal, neonatal (transitional), and infancy periods to understand hemodynamic adaptation during these periods. STUDY DESIGN: Fifty-three fetuses were enrolled in this study. Echocardiography evaluations were started as early as the sixteenth week of gestation and were repeated every 4 to 6 weeks until term, on postnatal days 1 and 2, and at 6 weeks, 6 months, and 12 months of age. End-diastolic and end-systolic measurements were made according to published standards. Mean and SEM for each of the end-diastolic and end-systolic measurements were calculated for each of 11 study periods. Data were analyzed by one-way analysis of variance, corrected for repeated measures, and in the case of right and left ventricular differences paired t tests were used for significance. RESULTS: Left ventricular end-diastolic and end-systolic correlated positively with advancing age (R2 = 0.93, p < 0.0001), right ventricular end-diastolic also correlated with advancing age (R2 = = 0.361, p < 0.05), and right ventricular end-diastolic was significantly larger than left ventricular end-diastolic in utero (p < 0.01), whereas the opposite was true after birth (p < 0.0001). Heart rate significantly decreased with advancing age (p < 0.001), whereas ejection fraction for either the right or the left ventricle did not change significantly with advancing age. CONCLUSION: This suggests that under basal conditions the ventricles can meet the increased demands in cardiac output by increasing ventricular dimensions without having to increase contractility reserve.

Child Development↗
PubMed1996

"On the spot' vaccination: does it work?

OBJECTIVE: To trial and evaluate a system of "on the spot' vaccination for children up to the age of 15 years in the Early Childhood Centres of the Central Sydney Area Health Service, at the Royal Alexandra Hospital for Children and in a number of general practices in the area. METHODOLOGY: A brief questionnaire was used to collect data from parents and health care professionals about the child's vaccination status and vaccines given "on the spot'. RESULTS: Over an 8 week period in August-September 1993, 5162 questionnaires were completed; 71% of children were up to date with their vaccination. If Haemophilus influenzae type b vaccine, which had been introduced only 2 months before commencement of the study, was excluded, 84% of the children were up to date. A total of 441 children were given 663 vaccinations "on the spot'. Very few children were too ill to be vaccinated (6%). However, only 30% of those who needed vaccination "on the spot' actually received it (441 of 1480), and only 41% (24 of 58) of a subset of those who were not vaccinated were known to have complied 1 month later. Children attending Early Childhood Centres were younger than children attending general practices or the hospital. CONCLUSIONS: A high proportion of children who attended for routine or acute health care had vaccinations overdue (30%). If this scheme could be continued and expanded it would have an important impact on vaccination coverage, and hence on the incidence of vaccine-preventable diseases.

Child↗