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Biomedical subjects

J Hannan

Publications and source records attributed to J Hannan.

At least 19 recordsLinked to original sources
PubMed2003

The effect of DXA scanning on clinical decision making by general practitioners: a randomized, prospective trial of direct access versus referral to a hospital consultant.

The objective of the study was to assess the impact of direct access DXA scanning (DADS) upon GPs' management decisions in patients considered to be at risk of osteoporosis. It was designed as a randomized, prospective, parallel group trial, set within the primary care environment and a university teaching hospital. The participants were 330 patients aged 31 to 89 years from 18 general practices in Edinburgh. Patients were randomized to either DADS or to the current system of specialist referral (controls). The primary outcome measure was frequency of change of management after DXA scanning. Secondary outcome measures were: change in health status, adherence to therapy, clinical events and resource use at one-year follow-up. The primary outcome was that 60% each of DADS patients (98/165) and controls (99/165) had changes in management following DXA scanning. In 30% of patients (12/41) in whom GPs had proposed changing management even in the absence of a scan, different therapy was chosen after the scan (no difference between DADS and control groups). There was an improvement in health utility (p =0.014 for both groups combined), differing slightly between the two groups even after age correction (p =0.014). 68% of the DADS group and 70% of controls were adherent to therapy after one year. In terms of clinical events, at one year there was one major adverse event (control group patient), 5 new fractures in the DADS group and 3 in controls - there were no hip fractures in this study. With regard to resource use, there were 24 referrals to hospital specialist after DXA scanning among the DADS group, vs 12 among controls (p < 0.05). The total number of visits to health professionals was 525 in DADS and 585 in controls (p=ns); mean waiting time from randomization to receipt of report/clinic letter was 4 weeks for DADS vs 13 weeks for controls( p < 0.0001). In conclusion, DXA scanning resulted in management change in at least 60% of cases. Direct access does not result in a clinical outcome significantly different from a consultant led service, and is more economically efficient than the current model of hospital referral.

Absorptiometry, Photon↗
PubMed2002

Structure of complement receptor (CR) 2 and CR2-C3d complexes.

Using X-ray crystallography, we have determined the structure of the first two short consensus repeats (SCRs) of human complement receptor (CR) 2 in complex with C3d. These studies revealed: (i) a primary site of interaction for C3d within SCR2 of CR2, (ii) a hydrophobic patch holding SCR1 to SCR2 in a rigid V-shape, (iii) a dimer formed by interactions between SCR1 of each molecule, (iv) several non-linear sequences on C3d that interact with CR2 and (v) mutations of C3d amino acids within the co-crystal interface that resulted in decreased binding. In addition, a polymorphism that results in decreased C3d binding and introduces a new glycosylation site predicted to disrupt the dimer interface was found in the New Zealand White autoimmune mouse strain. Although the co-crystal complex results are in agreement with a subset of prior studies, our additional findings, which demonstrate an extended SCR1-SCR2 structure in solution and differences in the kinetics of ligand-receptor interactions with longer forms of CR2, have suggested a more complex receptor-ligand interaction. To characterize this interaction further, several approaches directed at the determination of solution phase interactions as well as the analysis of the three-dimensional structure of CR2 alone and key CR2 mutants will be necessary.

Animals↗
PubMed2002

Solution structures of complement components by X-ray and neutron scattering and analytical ultracentrifugation.

The short consensus/complement repeat (SCR) domain (also known as the complement control protein domain) is the most abundant domain type in the complement system. Crystal and NMR structures for proteins that contain single and multiple SCR domains have now been published. These contain inter-SCR linkers of between three and eight residues, and the structures show much variability in inter-SCR orientations. X-ray and neutron scattering, combined with analytical ultracentrifugation and constrained modelling based on known subunit structures will yield a medium-resolution structure for the protein of interest. The fewer parameters that are associated with the structure of interest, the more defined the structure of interest becomes. These solution studies have been applied to several SCR-containing proteins in the complement system, most notably Factor H with 20 SCR domains, a complement receptor type 2 fragment with two SCR domains, and rat complement receptor-related protein (Crry) which contains five SCR domains. The results show great conformational variability in the inter-SCR orientation, and these will be reviewed. Even though the rotational orientation cannot be modelled, it is nonetheless possible to measure the degree of extension of the multi-SCR proteins and, from this, to obtain functionally useful results.

Animals↗
PubMed2000

Establishing nursing research priorities on a paediatric haematology, oncology, immunology and infectious diseases unit: a Delphi survey.

For research to be successfully integrated and applied to practice, ownership and identification must come from those who are most likely to implement research into practice. This was one of the reasons for undertaking a Delphi survey to identify and rank the research priorities for clinical nursing research in a paediatric haematology, oncology, immunology and infectious diseases unit. The 'Nurses' Research Group' initiated the survey as a first step towards developing a strategy for evidence-based nursing. Four members of the research group volunteered to establish a working party to undertake the survey. This paper describes a four-round Delphi survey. The survey questionnaire was sent to all nursing staff on the unit. The initial process identified 151 research topics/themes. Through a process of refinement the priority list was reduced to 89. Repeat rounds were completed, culminating in the identification of four top priority areas of: symptom management, negotiation of care between the child and family, quality-of-life issues and retention of staff. The findings indicate directions for future clinical nursing research that will benefit specialist nurses, children and young people and their families. This paper provides a detailed account of the method, procedure and outcomes of the Delphi survey. The limitations of the Delphi survey method are also addressed and in this survey these included time (the length of time it took to complete the survey and time needed to complete each questionnaire), maintaining motivation of respondents, and the influence of researchers working in the research setting.

Journal Article↗
PubMed2000

Total and regional bone density in male runners, cyclists, and controls.

PURPOSE: Male athletes who were runners (N = 12), cyclists (N = 14), or both (N = 13) were compared with nonexercising age-matched controls (N = 23) for total and regional bone mineral density (BMD). All athletic subjects had competed for a minimum of 3 yr and trained for a minimum of 4 h x wk(-1). Runners undertook no cycling and cyclists undertook no running training. METHODS: All subjects were scanned for whole body and L1-L4 spine BMD using a Hologic QDR 1000W scanner (Hologic Inc., Bedford, MA). RESULTS: There were no differences in age, height, weight, body mass index (BMI), % fat, or hours of training between any of the athletic groups (P > 0.05), although compared with controls, runners and cyclists had lower body mass index (P < 0.01) and all athletic groups had lower % fat (P < 0.001). Compared with controls, runners had greater total and leg BMD (P < 0.05), cyclists had reduced spine BMD (P = 0.05), and athletes of the "both" group had greater total (P < 0.05) and arm BMD (P < 0.01). CONCLUSION: Running is associated with increased bone density, particularly in the leg, whereas cycling is associated with a mild decrease in bone density in the spine. In athletes who do both, running exerts a stronger influence than cycling.

Adaptation, Physiological↗
PubMed2000

Sub-regional tissue morphometry in male athletes and controls using dual X-Ray absorptiometry (DXA).

Athletes have traditionally been evaluated for body composition by percent fat, percent muscle, and somatotype. Since the late 1980s, dual X-ray absorptiometry (DXA) has offered total and regional body composition of bone mineral content (BMC), lean tissue and fat, but studies involving athletes are rare (11) and have not included regional tissue distribution. In the present study, DXA was used to compare a total of 121 male subjects belonging to 9 different athletic groups and controls. ANOVA showed total tissue percent BMC, lean tissue, and fat were significantly different between the various athletic groups (p <.001). Regional differences in tissue distribution between different athletic groups affect BMC and lean tissue (p <.001), but not fat (p >.05). However, athletes of the leanest groups had different fat distribution to that of nonexercising controls (p <.01). It appears that fat distribution is nonspecific in its response to exercise, while lean and BMC distributions show highly specific adaptations to specific sports.

Absorptiometry, Photon↗
PubMed1997

Hemophilia and AIDS in married men: functioning of family members. Hemophilia PAC Project.

Aspects of functioning in families of 137 hemophilic men who, in 50% of cases, were also HIV seropositive were examined in terms of psychological and physical functioning and economic pressure. Results indicated that HIV-seropositive status, but not severity of hemophilia, was associated with poorer psychological and physical functioning of the husband, a poorer mother-child relationship, less support from outside the family for both spouses, and greater economic pressure on the family.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Attitudes, practices, and infection risks of hemophilia treatment center nurses who teach infection control for the home.

OBJECTIVE: To examine the practices toward infection control training and to assess the attitudes about, and risks for, exposures to blood among hemophilia treatment center (HTC) nurses who teach home infusion therapy (HIT). DESIGN AND POPULATION: Written and telephone interview surveys of the 153 nurses who teach HIT at federally funded HTCs. MAIN OUTCOME MEASURES: Hemophilia treatment center nurses' teaching practices and infection control messages taught, and frequency of exposures to blood. RESULTS: The response rate to the written nurses' survey was 60% and to the telephone interview 88%. Nurses taught patients a median of three HIT sessions totaling 4 hours of instruction. Reevaluation of patients' HIT practices took place every 6 months by 22% and every 12 months by 59% of nurses. Nurses frequently reported teaching proper use of a sharps disposal container (99%) and gloves (93%), but less often reported teaching patients to wash hands after infusions (26%) and to report needlestick injuries to HTCs (11%). The respondents identified several barriers to effective infection control as it is practiced in the home by patients. Although at least 30% of HTC nurses recalled having had percutaneous exposure to blood, they considered their risk for hepatitis B infection low but greater than for infection with the human immunodeficiency virus (HIV). CONCLUSIONS: While some important infection control messages are stressed during HIT teaching, others may be underemphasized. Failure to instruct patients about all infection control precautions may be related to nurse educators' perception of low to moderate personal risk for hepatitis B and HIV infection. Patients receiving HIT, and those who assist them, need to be fully aware of, and to have reinforced periodically, universal infection control strategies in the home.

Health Knowledge, Attitudes, Practice↗
PubMed1992

Bioelectrical impedance analysis in the measurement of the body composition of surgical patients.

The evaluation of nutritional status in surgical patients remains a difficult problem. Bioelectrical impedance analysis (BIA) is a new method of body composition analysis which is easily performed at the bedside. This study determined the accuracy of BIA in the measurement of total body water (TBW) and potassium (TBK) in a heterogeneous group of surgical patients. The resistance and reactance components of impedance were measured with a whole body impedance analyser. Tritiated water dilution and whole body monitoring were the reference methods for TBW and TBK analysis. With the BIA technique the coefficient of variation for the estimation of TBW was 8.1 per cent and for TBK was 6.4 per cent. Allowing for the errors of the reference methods these results show that BIA is of limited value in the estimation of TBW but may provide a useful index of TBK.

Adult↗
PubMed1992

Characterization of lipoprotein lipase activators from equine plasma.

Equine plasma lipoproteins were fractionated into VLDL, LDL-1, LDL-2 and HDL by density gradient ultracentrifugation. From each lipoprotein fraction, five apo C like peptides of approx. M(r) 1400, 10000, 9500, 9000 and 8000 were detected by SDS-polyacrylamide gel electrophoresis. After partial purification by Sephadex G-75, one fraction, showing a strong activation of lipoprotein lipase, was further purified by Mono Q anion exchange column. Two of the apo C like peptides (M(r) 10000 and 8000) activated the bovine milk lipoprotein lipase in vitro; only one (M(r) 9500) inhibited the lipolytic activity. This work confirms that many mammals present two apo C-II components with different molecular weights.

Animals↗
PubMed1991

The effect of isoprinosine and levamisole on factors relevant to protection of calves against respiratory disease.

Experiments to characterize the effects of two immunomodulators, namely, isoprinosine and levamisole, on factors relevant to the resistance of calves to respiratory infection were undertaken. Daily oral doses of isoprinosine decreased the influx of neutrophils into the respiratory tract, increased membrane immunoglobulin and complement receptor expression on cells from bronchoalveolar lavage samples and decreased the severity of respiratory disease. Additional intravenous doses produced similar effects on neutrophil migration to the respiratory tract and on membrane receptor expression, but the changes were no greater than those seen with oral isoprinosine alone. No significant changes in the anti-bacterial activity of cells in bronchoalveolar lavage samples followed isoprinosine treatment. In vitro incubation of pulmonary alveolar macrophages harvested from normal calves with isoprinosine increased their expression of immunoglobulin and complement receptors. Levamisole did not affect neutrophil migration to the lower respiratory tract or membrane receptor expression by pulmonary alveolar macrophages after in vivo or in vitro treatment. The immunomodulatory effects of isoprinosine beneficially increase the resistance of calves to respiratory disease, and are potentially useful in the control of infectious diseases of farm animals.

Administration, Oral↗
PubMed1990

Factors responsible for the introduction and spread of Campylobacter jejuni infection in commercial poultry production.

Campylobacter jejuni and related thermophilic campylobacters were not found in a hatchery or in chicks aged less than seven days. However, an increasing proportion of chicks aged two weeks and older shed campylobacters in their droppings. It was shown that a likely source of C jejuni for young chicks was the environment in the immediate vicinity of the rearing houses, and that infection could readily be introduced on the footwear and clothing of farm staff. Thermophilic campylobacters were found in the air, litter and drinking water containers in the rearing and finishing houses.

Air Microbiology↗
PubMed1990

Calibration of a prompt neutron activation analysis facility for the measurement of total body protein.

Prompt neutron activation analysis with 252Cf has been used to measure total body protein. Since simultaneous irradiation and detection generated a high count rate at the detectors the nucleonic system was optimised to reduce distortions in the gamma ray energy spectrum. Tissue-equivalent phantoms were used to calibrate the apparatus. A total of 53 studies was performed on 39 normal subjects. Ratios of total body protein to fat-free mass agreed well with those from other centres and with cadaver studies. Duplicate measurements of 14 subjects gave a coefficient of variation of +/- 2.9% for a measurement of total body protein, which is close to that calculated from the known errors of the technique of +/- 2.7%. The whole body dose equivalent was 0.17 mSv.

Activation Analysis↗
PubMed1987

Absorbed dose from 14C xylose and 14C mannose.

Tissue distribution and excretion studies have been performed in rats and mice for up to 1 week after oral administration of 14C xylose and 14C mannose. The effective dose-equivalent is calculated to be 15 microSv/MBq for xylose and 120 microSv/MBq for mannose. Since there was no clearance of mannose during the period of the study, the effective dose-equivalent for mannose is almost entirely dependent upon the assumptions made about expected lifetime exposure.

Absorption↗