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Biomedical subjects

John Howard

Publications and source records attributed to John Howard.

18 recordsLinked to original sources
PubMed2006

Electronically swept millimeter-wave interferometer for spatially resolved measurement of plasma electron density.

We report the development and initial implementation of what we believe to be a new rapid- spatial-scan millimeter-wave interferometer for plasma density measurements. The fast scan is effected by electronic frequency sweeping of a wideband (180-280 GHz) backward-wave oscillator whose output is focused onto a fixed blazed diffraction grating. The system, which augments the rotating-grating scanned multiview H-1 heliac interferometer, can sweep the plasma cross section in a period of less than 1 ms with a beam diameter in the plasma of 20 mm and phase noise of the order of 0.01 rad.

Journal Article↗
PubMed2006

Some characteristics of early-onset injection drug users prior to and at the time of their first injection.

AIMS: This paper examines differences between early- and late-onset injection drug users (12-16 years versus 17-24 years) in terms of the antecedents and circumstances of first injection. DESIGN: Cross-sectional retrospective design, using logistic regression. Setting Australia: Sydney, Brisbane, rural New South Wales. PARTICIPANTS: A total of 336 injection drug users aged 16-25 years at the time of interview. MEASUREMENTS: Independent variables included family injection drug use, homelessness and other demographic variables, drugs used prior to the first injection, length of pre-injection drug career, behaviours at time of first injection (e.g. drug injected, reasons/motives for the first injection, risk behaviours). FINDINGS: Early-onset injection was associated independently with: having a family who injected drugs, having left school early, an unreliable source of income, a short pre-injection drug career, planning of the first injection, reliance on others for administration of the first injection and denial that experimentation was the motive for the first injection. In bivariate analysis, early-onset injection was associated further with: homelessness, being an Indigenous Australian, omission of use of certain pre-injection drugs, group presence at first injection, reliance on others for acquisition of the first needle and syringe and having injected the first time because an injection was offered. CONCLUSIONS: The research shows that early-onset, compared with late-onset injectors, are more likely to have an immediate family who inject drugs and other problematic beginnings in early life. They have an accelerated transition to injection, and differences in autonomy and motivation at first injection. These characteristics may make them more vulnerable to risk taking.

Adolescent↗
PubMed2006

Exercise and Crohn's disease: speculations on potential benefits.

Crohn's disease (CD) is a chronic inflammatory bowel disease that affects nearly one million people in the United States and Canada. While current pharmaceutical treatments are effective in controlling symptoms, patients continue to experience a reduced quality of life (QOL). Based on preliminary studies, QOL in CD patients may be improved by engaging in physical activity. Exercise may decrease CD activity and reduce psychological stress. Current research also suggests that low-intensity exercise does not exacerbate gastrointestinal symptoms and does not lead to flare-ups. Furthermore, exercise appears to reduce CD symptoms and improve QOL. In summary, physical activity may be beneficial to certain patient groups, but more studies are needed before broad recommendations can be made.

Bone Density↗
PubMed2005

Gun storage practices and risk of youth suicide and unintentional firearm injuries.

CONTEXT: Household firearms are associated with an elevated risk of firearm death to occupants in the home. Many organizations and health authorities advocate locking firearms and ammunition to prevent access to guns by children and adolescents. The association of these firearm storage practices with the reduction of firearm injury risk is unclear. OBJECTIVE: To measure the association of specific household firearm storage practices (locking guns, locking ammunition, keeping guns unloaded) and the risk of unintentional and self-inflicted firearm injuries. DESIGN AND SETTING: Case-control study of firearms in events identified by medical examiner and coroner offices from 37 counties in Washington, Oregon, and Missouri, and 5 trauma centers in Seattle, Spokane, and Tacoma, Wash, and Kansas City, Mo. CASES AND CONTROLS: Case firearms were identified by involvement in an incident in which a child or adolescent younger than 20 years gained access to a firearm and shot himself/herself intentionally or unintentionally or shot another individual unintentionally. Firearm assaults and homicides were excluded. We used records from hospitals and medical examiners to ascertain these incidents. Using random-digit dial telephone sampling, control firearms were identified by identification of eligible households with at least 1 firearm and children living or visiting in the home. Controls were frequency matched by age group and county. MAIN EXPOSURE MEASURES: The key exposures of interest in this study were: (1) whether the subject firearm was stored in a locked location or with an extrinsic lock; (2) whether the firearm was stored unloaded; (3) whether the firearm was stored both unloaded in a locked location; (4) whether the ammunition for the firearm was stored separately; and (5) whether the ammunition was stored in a locked location. Data regarding the storage status of case and control guns were collected by interview with respondents from the households of case and control firearms. RESULTS: We interviewed 106 respondents with case firearms and 480 with control firearms. Of the shootings associated with the case firearms, 81 were suicide attempts (95% fatal) and 25 were unintentional injuries (52% fatal). After adjustment for potentially confounding variables, guns from case households were less likely to be stored unloaded than control guns (odds ratio [OR], 0.30; 95% confidence interval [CI], 0.16-0.56). Similarly, case guns were less likely to be stored locked (OR, 0.27; 95% CI, 0.17-0.45), stored separately from ammunition (OR, 0.45; 95% CI, 0.34-0.93), or to have ammunition that was locked (OR, 0.39; 95% CI, 0.23-0.66) than were control guns. These findings were consistent for both handguns and long guns and were also similar for both suicide attempts and unintentional injuries. CONCLUSIONS: The 4 practices of keeping a gun locked, unloaded, storing ammunition locked, and in a separate location are each associated with a protective effect and suggest a feasible strategy to reduce these types of injuries in homes with children and teenagers where guns are stored.

Adolescent↗
PubMed2005

EXUBERA: pharmaceutical development of a novel product for pulmonary delivery of insulin.

Development of a product for pulmonary delivery of insulin presented significant technology challenges for this first-in-class pharmaceutical product. These included developing (a) a chemically stabilized protein, (b) a dry powder formulation exhibiting required aerosol physical characteristics, (c) low-dose powder filling and packaging technology, and (d) a mechanical device for powder dispersal and reliable dosing to the patient. The insulin drug is formulated using a novel excipient combination to create a powder with a high glass transition temperature (Tg). The high Tg minimizes insulin mobility (thus reactivity), enabling ambient storage conditions. The formulation composition results in minimal hygroscopicity, where customized packaging produced product ruggedness to humidity. The formulated insulin powder is manufactured by spray-drying. This technology was further engineered to produce the desired reproducible powder characteristics with tight control over particle size and moisture content. A solution step prior to drying assures homogeneity and minimizes dependence on the physical form of the components. Novel low-dose filling and packaging technology reproducibly meters milligram quantities of microfine powder to meet stringent quality requirements for dose control. The technology for accurate, uniform, high-throughput metering of drug powders allows for automation and is scaleable for commercial operations. Finally, the mechanical device design provides powder deagglomeration and dispersion processes in a reusable dry powder inhaler with unique characteristics. The device was designed to rely on patient-generated compressed air as the energy source. A sonic discharge of air through the novel TransJector reproducibly extracts, deagglomerates, and disperses the inhalation powder. A clear holding (spacer-type) chamber allows for patient feedback via dose visualization, and separates powder dispersal from the inspiratory effort. The EXUBERA [Pfizer (New York, NY) and sanofi-aventis (Paris, France)] product provides insulin into the bloodstream with similar reproducibly and effectiveness as subcutaneous injections.

Administration, Inhalation↗
PubMed2005

An international comparison of information in adverse events.

PURPOSE: Aims to describe the growing importance of information and its governance within public services. The paper starts by considering how scandals in three national public health systems have focused public attention on information issues. It describes a theoretical framework for improving information governance, and its practical implementation as a management tool. The paper concludes with a discussion of the benefits of the approach, and the consequences of not improving information governance. DESIGN/METHODOLOGY/APPROACH: The framework brings together a number of existing methodological approaches, principally the maturity model approach to process improvement, first described in the Software Engineering Institute's capability maturity model, and the novice-to-expert approach to competency. FINDINGS: The paper describes how these approaches can be synthesised into an integrated framework to manage organisational change and how that can be used to improve information governance within public sector organisations. RESEARCH IMPLICATIONS: The paper compares the framework and its practical implementation with existing solutions, arguing that existing solutions provide only partial solutions. ORIGINALITY/VALUE: Considers how plans for future service improvements will be restricted unless information governance issues can be addressed.

Australia↗
PubMed2004

Fatal rat bite fever in a pet shop employee.

BACKGROUND: Rat bite fever is a zoonotic disease that has been described in laboratory personnel as well as the general population. METHODS: A 24-year-old male pet shop employee contracted the disease through a minor superficial finger wound on a contaminated rat cage. The disease progressed from a flu-like illness to endocarditis involving first the aortic valve and then the mitral valve and septum. Despite aggressive therapy including two surgical procedures, the patient died from sepsis and multi-organ system failure 59 days after initial injury. RESULTS: This is the first reported case of rat-bite fever (RBF) in a pet shop work setting. CONCLUSIONS: Zoonotic infections may present a significant hazard to workers handling animals. Education on hazards of animal contact and other preventive measures are needed in small places of business like pet shops.

Adult↗
PubMed2004

Smoking is an occupational hazard.

BACKGROUND: Even though the prevalence of tobacco smoking has declined in the general population and among white-collar workers, the prevalence of tobacco smoking among blue-collar workers remains unacceptably high. Blue-collar workers experience greater exposure to workplace toxins which can add to, or even multiply, their risk of adverse health effects from tobacco smoking. Among blue-collar workers, workers in the restaurant, bar, and gaming industries are exposed to much higher levels of environmental tobacco smoke (ETS) than are office workers, and are at increased risk of cancer and cardiovascular diseases even if they are non-smokers themselves. METHODS: The literature on health risks, and the disparity between white and blue collar workers in smoking prevalence, and the literature on various tobacco control strategies provide the sources on which this review is based. CONCLUSIONS: Over the past 20 years, the accumulating scientific evidence about smoking as an occupational hazard has prompted the implementation of various educational, economic, and legal tobacco control strategies.

Health Promotion↗
PubMed2004

Effectiveness of crime prevention through environmental design in reducing criminal activity in liquor stores: a pilot study.

Liquor store employees experience disproportionately higher rates of workplace injury death than employees in any other retail setting. However, efforts to introduce workplace violence prevention programs into liquor stores have been minimal. This study examines the effectiveness of a Crime Prevention Through Environmental Design intervention in reducing criminal activity in Santa Monica, California liquor stores. Nine stores enrolling in the study received an individualized intervention safety plan; the remaining 13 served as a comparison group. Mixed-effects Poisson regression was used to examine intervention effectiveness. The largest reductions in criminal activity occurred for robbery and shoplifting outcomes. We conclude that the Crime Prevention Through Environmental Design program reduced crime and injury in liquor stores and educated small businesses about the risks associated with retail violence and the countermeasures that can be taken.

Alcohol Drinking↗
PubMed2004

Tramadol (Ultram) concentrations in death investigation and impaired driving cases and their significance.

We reviewed a series of 66 deaths in Washington State between 1995-2000 in which tramadol (Ultram and Ultracet, Ortho-McNeil) was detected in the decedent's blood, in order to assess the role tramadol was determined to have played. Additionally, we reviewed a series of 83 impaired driving cases in which tramadol was detected in order to establish a non-lethal blood tramadol concentration reference range. In both populations, tramadol was consistently found together with other analgesic, muscle relaxant, and CNS depressant drugs. Death was rarely attributable to tramadol alone. However, tramadol may be a significant contributor to lethal intoxication when taken in excess with other drugs, via the potential interaction with serotonergic antidepressant medications, as well as the potential for increased CNS depression. Although the incidence of tramadol detection has increased consistently over the last eight years, there is no evidence of a corresponding increase in the number of cases in which death was attributed solely to tramadol. Blood drug concentrations in many deaths exceeded the therapeutic serum range of 0.28-0.61 mg/L; however, the concentrations overlapped almost completely with the range identified in living subjects arrested for impaired driving. These findings suggest caution in the interpretation of blood tramadol concentrations outside of the recognized therapeutic range. It also suggests that the drug, even when used in moderate excess, is not a principle cause of death in suicidal or accidental deaths.

Analgesics, Opioid↗
PubMed2003

Sensitivity of spirometric measurements to detect airway obstruction in infants.

We evaluated the ability of forced expiratory flow volume curves from raised lung volumes to assess airway function among infants with differing severities of respiratory symptoms. Group 1 (n = 33) had previous respiratory symptoms but were currently asymptomatic; group 2 (n = 36) was symptomatic at the time of evaluation. As a control group, we used our previously published sample of 155 healthy infants. Flow volume curves were quantified by FVC, FEF50, FEF75, FEF25-75, FEV0.5, and FEV0.5/FVC, which were expressed as Z scores. All variables except FVC had Z scores that were significantly less than zero and distinguished groups 1 and 2 with progressively lower Z scores. The mean Z scores of the flow variables (FEF50%, FEF75%, and FEF25-75%) were more negative than the Z scores for the timed expired volumes (FEV0.5 or FEV0.5/FVC) for both groups. In general, measures of flow identified a greater number of infants with abnormal lung function than measures of timed volume; FEF50 had the highest performance in detecting abnormal lung function. In summary, forced expiratory maneuvers obtained by the raised volume rapid compression technique can discriminate among groups of infants with differing severity of respiratory symptoms, and measures of forced expiratory flows were better than timed expiratory volume in detecting abnormal airway function.

Age Factors↗
PubMed2003

Linking health and ecology in the medical curriculum.

Human health vulnerabilities to ecosystem degradation are well documented. Destabilization of natural ecosystems and the biosphere have posed an entirely new set of risks to human health and preclude any simple extrapolations from the past. Newly emerging diseases, increasing prevalence of many vector borne diseases, increased exposure to harmful UV radiation and a number of other transformations in the natural environment, have decidedly negative implications for the sustainability of human health. Curricula in medical schools are responding to these new realities by exposing the connections between health and ecology. The program in Ecosystem Health at the University of Western Ontario serves as one model for connecting these disciplines. This program has resulted in a perceptible shift in values and professional responsibilities of emerging physicians.

Air Pollutants↗
PubMed2003

Patterns and correlates of substance use amongst juvenile detainees in New South Wales 1989-99.

In the decade 1989 - 99 there have been significant changes in the patterns of substance use in the Australian community. Juvenile offenders have been a sentinel population of these emerging trends. The social and personal costs associated with adolescent substance use, especially where it leads to increased criminal offending requires urgent attention. This study was a replication of the 1989 and 1994 surveys of young people in detention in New South Wales, Australia. The 300 voluntary participants from nine detention centres had a similar demographic profile to participants of the previous surveys. They were predominantly male (90%) with a mean age of 16.5 years and an over-representation of Aboriginal and Torres Straits Islander peoples. The patterns of lifetime alcohol and tobacco use were stable over the decade, with particular increases in amphetamine, opioid and cocaine use since 1994. The more concerning pattern of at least weekly substance use revealed significant increases in cannabis, opioid and cocaine use since 1994, but a significant decrease in the frequent use of alcohol. This study also reports on high levels of negative health and psychosocial consequences of substance use, including overdose, among this group. High levels of self-reported depression and suicidal behaviours, family and gender issues are also discussed. Encouragingly, there was a relatively high level of self-recognized treatment need for substance use and mental health problems among the sample. This highlights further the growing need for the development and dissemination of novel interventions that harness this willingness and actively engage, motivate and maintain these young people in accessible, appropriate and effective interventions.

Adolescent↗
PubMed2002

Long-term results of pediatric liver transplantation in a combined pediatric and adult transplant program.

BACKGROUND: Liver transplantation is now routine therapy for a variety of childhood liver diseases; however, there are no detailed reports of long-term results from a Canadian centre. We reviewed data from the first 16 years of a pediatric liver transplantation program to determine survival, complications and long-term outcomes. METHODS: The outcomes to December 2000 for all children (age less than 18 years) who received a liver transplant at the London Health Sciences Centre between April 1984 and December 1999 were reviewed. The recipients were grouped according to the period in which they received the transplant (period 1, April 1984 to July 1988; period 2, August 1988 to December 1993; or period 3, January 1994 to December 1999). Data were obtained from medical charts; in-person interviews, questionnaires or telephone contact with patients and their families; contact with referring physicians; and school records. Outcome measures included patient survival, retransplantation, complications and long-term outcomes (specifically steroid withdrawal and growth and development). RESULTS: A total of 116 children (29 in period 1, 46 in period 2 and 41 in period 3) (median age 5.6 years at the time of the procedure) received a total of 140 liver grafts (32 in period 1, 57 in period 2 and 51 in period 3). Of the 116 patients, 23 (20%) were less than 1 year old at the time of transplantation. Biliary atresia was the most common indication for liver transplantation (57 [49%] of the 116 patients). The number of patients surviving to 1 year after transplantation was 20 (69%) of the 29 patients from period 1, 40 (87%) of the 46 patients from period 2 and 38 (93%) of the 41 patients from period 3. The percentage of patients receiving reduced size grafts from adult donors, including live donors, increased from 2/32 (6%) in period 1 to 22/51 (43%) in period 3. Retransplantation was required for 9 (31%) of the 29 patients from period 1, 6 (13%) of the 46 patients from period 2 and 7 (17%) of the 41 patients from period 3. Among these patients, 1-year survival was 33% (3/9) for period 1, 83% (5/6) for period 2 and 100% (7/7) for period 3. Eighteen of the 22 deaths occurred within 4 months after surgery. Only 3 (3%) of the 116 patients experienced post-transplant lymphoproliferative disease. Steroids were discontinued (usually within 2 years after surgery) for the following proportions of surviving transplant recipients: 17 (89%) of the 19 patients from period 1, 29 (78%) of the 37 patients from period 2 and 21 (55%) of the 38 patients from period 3. Most of the surviving patients had normal growth (82/94 or 87%) and development (73/94 or 78%), and these outcomes were consistent across the 3 periods of study. INTERPRETATION: Survival and long-term outcomes continue to improve for most children who receive liver transplants. These improvements may be due to improved surgical technique, perioperative care and, to a lesser extent, immunosuppressive therapy.

Adult↗
PubMed2002

Electro-optically modulated polarizing Fourier-transform spectrometer for plasma spectroscopy applications.

A new electro-optically modulated optical solid-state (MOSS) interferometer has been constructed for measurement of quantities related to the low-order spectral moments of line emission from optically thin radiant media such as plasmas. When Doppler broadening is dominant, the spectral moments give the Radon transform of corresponding moments of the velocity distribution function of the radiating species. The instrument, which is based on the principle of the Fourier-transform spectrometer, has high etendue and is rugged and compact. When electro-optical path-length modulation techniques are employed, the spectral information is encoded in the temporal frequency domain at harmonics of the modulation frequency and can be obtained by use of a single photodetector. Specifically, for a plasma in drifting local thermodynamic equilibrium the zeroth moment (brightness) is given by the average signal level, the first moment (shift) by the interferometric phase, and the second moment (linewidth) by the fringe visibility. To illustrate the MOSS performance, I present spectroscopic measurements of the time evolution of the plasma ion temperature and flow velocity for rf-heated discharges in the H-1 heliac, a toroidal plasma magnetic confinement at the Australian National University.

Journal Article↗
PubMedDate not supplied

Benchmarking implementation of a computerized system for long-term care.

The purpose of this study was to apply a benchmarking methodology to identify the most effective approaches used by long-term care facilities in implementing new computerized resident assessment instrument/minimum data set (RAI/MDS) systems and to develop implementation protocols based on these "best practices." Site visits were conducted with 3 long-term care facilities, selected on the basis of a national search. Facility directors, directors of nursing, information system managers, and frontline staff at each facility were targeted, and questionnaires were developed for each to assess factors viewed as important to successful implementation. A convergence was found in recommended action steps reported across sites to facilitate introduction and implementation of new RAI/MDS software. An example of how benchmarking results were used to develop an implementation plan is provided. Benchmarking provided a useful methodology for identifying best practices to guide implementation planing for adoption of a new computerized RAI/MDS system in the current trial. The benchmarking steps described are replicable and can be used to guide implementation of other new systems in the nursing home setting.

Benchmarking↗