Search PubMed⌕ Search

Biomedical subjects

M Hebert

Publications and source records attributed to M Hebert.

At least 19 recordsLinked to original sources
PubMed2005

Delivery of rural and remote health care via a broadband Internet Protocol network - views of potential users.

We asked the views of potential users of a proposed Canadian broadband Internet Protocol (IP) network for health, the Alberta SuperNet. The three user groups were drawn from the public, provider and private sectors. In all, 35 health-sector participants were selected (17 government, nine health-care organizations, five providers/practitioners and four private sector). The questionnaire was Web-based, semistructured and self-administered. It consisted of four major areas: value, readiness, effect on usual care and limitations. A total of 28 (80%) individuals responded to the questionnaire: 21 (81%) were from the public sector (three provincial, nine regional and nine organizational), three (60%) were from the provider sector and four (100%) were from the private sector. Overall, the items related to health services and health human resources were considered to be the most valuable to rural communities. Respondents identified the expansion of telehealth services as the most important, except those from the private sector, who ranked this a close second. The health system's move to the use of electronic health records was ranked second in importance by all respondents. The private-sector respondents viewed all user groups to be generally less ready (mean score 2.5 on a seven-point scale from 1 = not ready to 7 = ready), while the public-sector respondents were the most optimistic (mean score 4.0). Specific socioeconomic impact data were limited. The top-ranked disadvantage of the 10 suggested was that 'Changes in health-service delivery practices and/or processes will be required'.

Alberta↗
PubMed2004

Effect of contraction frequency on energy expenditure and substrate utilisation during upper and lower body exercise.

OBJECTIVE: To examine the effect of contraction frequency on energy expenditure and substrate utilisation during upper (UE) and lower (LE) body exercise. METHODS: Twenty four college students were recruited: 12 were tested on an arm ergometer, and the other 12 were tested on a leg ergometer. Each subject underwent three experimental trials on three separate days, and the three trials were presented in a randomised order. Each trial consisted of 10 minutes of arm cranking or leg cycling at 40, 60, or 80 rev/min, with power output being kept constant at 50 W. Steady state oxygen uptake (VO(2)) and respiratory exchange ratio (RER) were measured during each exercise. Energy expenditure was calculated from the steady state VO(2) adjusted for substrate metabolism using RER. Carbohydrate and fat oxidation were calculated from VO(2) and RER based on the assumption that protein breakdown contributes little to energy metabolism during exercise. RESULTS: Energy expenditure was greater (p<0.05) at 80 rev/min than at 40 rev/min. No difference was found between 40 and 60 rev/min and between 60 and 80 rev/min during both UE and LE. During LE, carbohydrate oxidation was also higher at 80 rev/min than at 40 rev/min, whereas no difference in fat oxidation was found among all three pedal rates. During UE, no speed related differences in either carbohydrate or fat utilisation were observed. CONCLUSIONS: Pedalling at a greater frequency helped to maximise energy expenditure during exercise using UE or LE despite an unchanging power output. Whereas contraction frequency affects energy expenditure similarly during both UE and LE, its impact on carbohydrate utilisation appears to be influenced by exercise modality or relative exercise intensity.

Adult↗
PubMed2001

The realities of synthesizing and disseminating research evidence.

This article describes the results of a 15-month pilot project to determine whether producers and users of organizations' research findings can synthesize and disseminate evidence collaboratively. The findings of the project suggest that the collaborative approach is a feasible but costly endeavor owing to differences in need, expertise, experience and context. Funding agencies should consider alternative ways to build sustainable partnerships and to address the cultural and political contexts of organizations involved with the synthesis and dissemination of evidence.

Cooperative Behavior↗
PubMed2001

Telehealth success: evaluation framework development.

Implementing telehealth applications represents a substantial investment of resources, which is one reason why success is of great interest. Many research and evaluation studies have investigated measures of successful telehealth systems. However, the term "telehealth" represents a wide range of variables including clinical application, characteristics of the information being transmitted, temporal relationships of data transfer and the organizational context. These sources of variability pose many challenges for evaluation as well as for building a cumulative history of research. A conceptual framework is required that assists in categorizing results and drawing conclusions based on an accumulation of findings. One measure of "success" in health care is quality patient care and this reflects a primary reason for ICT investments. For this reason, Donabedian's work in evaluating quality provides the basis for the proposed framework. DeLone and McLean's definitions of IS success assist in conceptualizing Donabedian's structure-outcome-process variables in a telehealth context. Multiple evaluation approaches have been used to address different types of questions. Prior to the technologies being introduced to clinical care, there are usually many studies to demonstrate their effectiveness. Health Technology Assessment examines a broader context than the technology alone, including costs and comparing alternatives that would exist in the absence of telehealth. It considers performance measures; outcomes; summary measures, operational considerations, and other issues. Program Evaluation examines use of the technology to provide a service or deliver a program. Evaluation questions often address whether the program goals have been met and if it is operating as expected. Perhaps of greater concern than the evaluation approach taken is generalizability of findings. Recent studies have given inadequate attention to defining what is done (i.e. comparison of telehealth to most appropriate alternative), identifying the beneficiaries of telehealth (i.e. ensuring randomly selected participants take part) and what is measured (i.e. including benefits, drawbacks and side effects of telehealth). Evaluation efforts and frameworks have identified "success" factors such as technical acceptability of the system, cost/benefit/effectiveness, organizational support, satisfaction, recruitment and retention, client outcomes such as quality of life, acceptance by consumers and providers. Less is known about the relationship among these variables and whether the findings around one variable are generalizable to other settings or applications. For example, organizational support may be essential for successful provider-patient interactions via videoconference, which result in higher quality of life. A conceptual framework would assist in accumulating this type of evidence and supporting more advanced research efforts.

Computer Communication Networks↗
PubMed2000

Improved branching ratio measurement for the decay K(0)(L) --> &mgr;(+)&mgr;(-)

We report results from Experiment 871, performed at the BNL AGS, of a measurement of the branching ratio K(0)(L)-->&mgr;(+)&mgr;(-) with respect to the CP-violating mode K(0)(L)-->pi(+)pi(-). This experiment detected over 6200 candidate &mgr;(+)&mgr;(-) events, a factor of 6 more than that seen in all previous measurements combined. The resulting branching ratio gamma(K(0)(L)-->&mgr;(+)&mgr;(-))/gamma(K(0)(L)-->pi(+)pi(-)) = (3. 474+/-0.057)x10(-6) leads to a branching fraction B(K(0)(L)-->&mgr;(+)&mgr;(-)) = (7.18+/-0.17)x10(-9), which is consistent with the current world average, and reduces the uncertainty in this decay mode by a factor of 3.

Journal Article↗
PubMed2000

Cocaine-induced sniffing stereotypy changes in response to threat.

"Cocaine-induced stereotypies" have been extensively investigated on the basis that they may be capable of providing insights into behavioral and neurochemical mechanisms relevant to drug abuse and addiction. Recent work has indicated that cocaine enhances a number of defensive behaviors, and, that cocaine-enhanced sniffing may be a functional behavior pattern, potentially related to defense, prompting an investigation of the effects of threat stimuli on cocaine-enhanced sniffing. When behaviors of saline control rats were evaluated in their home cages (HC), or on exposure to a toy cat (TC) or real cat (RC), they showed minimal crouching in the HC; initial crouching declining over 5 days of repetitions to the TC; and continued, high-level crouching to the RC. Cocaine (30 mg/kg, IP) enhanced defensiveness in situations in which it had declined in the TC and RC groups. It also produced high-level sniffing, declining over 5 test days, in the HC; initial low-level sniffing to the TC, increasing over 5 test days; and very low levels of sniffing to the RC. These and previous data contribute to a view that cocaine enhances, but does not directly induce, defensive behaviors. They also indicate that external threat stimuli such as the RC, or initial presentation of the TC suppress sniffing, with sniffing returning as habituation to novel but not intrinsically dangerous stimuli reduces defensiveness. This view suggests that some component of "sensitization of cocaine-induced sniffing stereotypy" may reflect a release from defensiveness-mediated suppression of sniffing over repeated injection/testing as the subject becomes habituated to the injection procedure and to novel test situations.

Animals↗
PubMed2000

Failure of extraocular light to facilitate circadian rhythm reentrainment in humans.

Although extraocular light can entrain the circadian rhythms of invertebrates and nonmammalian vertebrates, almost all studies show that the mammalian circadian system can only be affected by light to the eyes. The exception is a recent study by Campbell and Murphy that reported phase shifts in humans to bright light applied with fiber-optic pads behind the knees (popliteal region). We tested whether this extraocular light stimulus could accelerate the entrainment of circadian rhythms to a shift of the sleep schedule, as occurs in shift work or jet lag. In experiment 1, the sleep/dark episodes were delayed 8h from baseline for 2 days, and 3h light exposures were timed to occur before the temperature minimum to help delay circadian rhythms. There were three groups: (1) bright (about 13,000 lux) extraocular light from fiber-optic pads, (2) control (dim light, 10-20 lux), and (3) medium-intensity (about 1000 lux) ocular light from light boxes. In experiment 2, the sleep/dark episodes were inverted, and extraocular light was applied either before the temperature minimum to help delay circadian rhythms or after the temperature minimum to help advance rhythms. Circadian phase markers were the salivary dim light melatonin onset (DLMO) and the rectal temperature minimum. There was no evidence that the popliteal extraocular light had a phase-shifting effect in either experiment. Possible reasons for phase shifts in the Campbell and Murphy study and not the current study include the many differences between the protocols. In the current study, there was substantial sleep deprivation before the extraocular light was applied. There was a large shift in the sleep/dark schedule, rather than allowing subjects to sleep each day from midnight to noon, as in the Campbell and Murphy study. Also, when extraocular light was applied in the current protocol, subjects did not experience a change from sleeping to awake, a change in posture (from lying in bed to sitting in a chair), or a change in ocular light (from dark to dim light). Further research is necessary to determine the conditions under which extraocular light might produce phase shifts in human circadian rhythms.

Adult↗
PubMed1998

Professional and organizational impact of using patient care information systems.

Evaluation of information systems has often been limited to success factors in relation to system implementation (on time and on budget), training and use of the system. Little attention has been paid to the longer-term effect of using these systems and the resulting issues for health care professionals and organizations. This paper reports on a multiple case study of community hospitals, which examined the impact of using Patient Care Information Systems. An analytic framework incorporated Donabedian's 3 aspects of quality care: structure, process and outcome. These were examined at three levels of impact; direct substitution, proceduralization and new capabilities. Many of the anticipated benefits in the study did not occur because changes occurring in structure (generally taks done by pharmacists and laboratory technologists) did not automatically influence process changes (such as decision making of physicians and nurses) or patient outcomes. Four themes illustrate important professional and organizational issues with implications for worklife of professionals, management and career training. They include the effects of increased efficiency and productivity; "visible" accountability; changing roles and responsibilities; and learning to use new technology versus using new information.

British Columbia↗
PubMed1997

Fulminating bacteremia and pneumonia due to Bacillus cereus.

We present two cases of rapidly progressing, fatal pneumonia caused by Bacillus cereus. These cases are interesting in that B. cereus, even from blood or sputum specimens, may often be considered a contaminant and receive inadequate attention. Also of interest was the fact that the two patients resided in the same area of the state, were welders by trade, and became ill within a few days of each other, yet there was no epidemiologic link between them.

Adult↗
PubMed1996

Attack priming in female Syrian golden hamsters is associated with a c-fos-coupled process within the corticomedial amygdala.

Allowing a resident hamster a single "priming" attack on a conspecific induces a transient aggressive arousal as indicated by a reduction in the latency and increase in the probability of attack on a second intruder presented within the next 30 min. We present two lines of evidence identifying the corticomedial amygdala as an important locus mediating this effect. (1) Attack priming significantly increases the number of neurons expressing immunocytochemically identified Fos protein in the corticomedial amygdala, but not elsewhere. Pursuit and biting of an inanimate object does not induce corticomedial amygdala c-fos expression of the same pattern or magnitude. The corticomedial amygdala contribution to the priming effect involves more than a non-specific arousal, since corticomedial amygdala c-fos expression does not correlate with locomotor activity, a standard indicator of such arousal. (2) Radiofrequency lesions of the corticomedial amygdala reduce aggression, the greatest reduction occurring with the more anterior lesions. Other behaviors, including a priming-like locomotor practice effect in a running wheel, are unaffected by corticomedial amygdala lesions. These findings suggest that attack priming is an aggression-specific effect resulting from a Fos-coupled change within neural circuitry of which the corticomedial amygdala is a part. From a theoretical point of view, these experiments suggest a new approach to the analysis of the mechanisms underlying aggressive behavior and the persistence of aggressive arousal. We present a sketch of a quantitative neurobehavioral model which relates attack probability to neural activation within the corticomedial amygdala. From a methodological viewpoint, these experiments extend the utility of mapping c-fos expression as a technique for localizing endogenous, behavior-specific processes within the central nervous system.

Aggression↗
PubMed1996

Brief, high-frequency stimulation of the corticomedial amygdala induces a delayed and prolonged increase of aggressiveness in male Syrian golden hamsters.

Brief 200-Hz stimulation of the corticomedial amygdala (CMA) increases the aggressiveness of male Syrian golden hamsters for about 30 min; the effect peaks 10-15 min after stimulation. This effect is sensitive to stimulation amplitude and frequency. Stimulation at the parameters that reduce attack latency increases flank marking but does not affect copulation latency or general activity. Immunocytochemical analysis suggests that stimulation effects may be coupled to c-fos expression and that unilateral stimulation has bilateral effects. CMA stimulation effects appear to mimic part of the time course of behaviorally induced attack priming. The temporal persistence of aggression may result from long-term potentiation-like changes within CMA-related neural circuitry.

Aggression↗
PubMed1995

Techniques for fast and accurate intrasurgical registration.

The goal of intrasurgical registration is to establish a common reference frame between presurgical and intrasurgical three-dimensional data sets that correspond to the same anatomy. This paper presents two novel techniques that have application to this problem, high-speed pose tracking and intrasurgical data selection. In the first part of this paper, we describe an approach for tracking the pose of arbitrarily shaped rigid objects at rates up to 10 Hz. Static accuracies on the order of 1 mm in translation and 1 degree in rotation have been achieved. We have demonstrated the technique on a human face using a high-speed VLSI range sensor; however, the technique is independent of the sensor used or the anatomy tracked. In the second part of this paper, we describe a general purpose approach for selecting near-optimal intrasurgical registration data. Because of the high costs of acquisition of intrasurgical data, our goal is to minimize the amount of data acquired while ensuring registration accuracy. We synthesize near-optimal intrasurgical data sets, based on an analysis of differential surface properties of presurgical data. We demonstrate, using data from a human femur, that discrete-point data sets selected using our method are superior to those selected by human experts in terms of the resulting pose-refinement accuracy.

Algorithms↗
PubMed1994

Adopting information technology in hospitals: the relationship between attitudes/expectations and behavior.

The purpose of this field study was to measure the influence of three factors on the adoption of information technology in a health care setting--namely, attitudes toward using the technology, subjective norms or beliefs about others' expectations, and perceived voluntariness. Approximately 77 percent of the variance of intent to use the technology was explained by three attitude variables (beliefs related to perceived relative advantage and compatibility with previous work patterns as well as result demonstrability), and one variable associated with subjective norms (influence of a senior policymaker, the director of nursing). Use of this model may provide insights for administrators managing the process of information technology implementation in health care.

Alberta↗
PubMed1993

Local failure and margin status in early-stage breast carcinoma treated with conservation surgery and radiation therapy.

OBJECTIVE: The authors determined whether microscopically positive surgical margins are detrimental to the outcome of early stage breast cancer patients treated with conservation surgery and radiation therapy. SUMMARY BACKGROUND DATA: The optimal extent of breast surgery required for patients treated with conservation surgery and radiation therapy has not been established. To achieve breast preservation with good cosmesis, it is desirable to resect as little normal tissue as possible. However, it is critical that the resection does not leave behind a tumor burden that cannot be adequately managed by moderate doses of radiation. It is not known whether microscopically positive surgical margins are detrimental to patient outcome. METHODS: The records of 259 consecutive women (262 breasts) treated with local excision (complete removal of gross tumor with a margin) and axillary dissection followed by radiation therapy for clinical stage I and II infiltrating ductal breast cancer at Duke University Medical Center and the University of North Carolina between 1983 and 1988 were reviewed. Surgical margins were considered positive if tumor extended to the inked margins; otherwise the margins were considered negative. Margins that could not be determined, either because the original pathology report did not comment on margins, or because the original specimen had not been inked were called indeterminate. RESULTS: Of the 262 tumors, 32 (12%) had positive margins, 132 (50%) had negative margins, and the remaining 98 (38%) had indeterminate margins. There were 11 (4%) local failures; 3/32 (9%) from the positive margin group, 2/132 (1.5%) from the negative margin group, and 6/98 (6%) from the indeterminate group. The actuarial local failure rates at 5 years were 10%, 2%, and 10%, respectively, p = 0.014 positive vs. negative, p = 0.08 positive vs. indeterminate (log rank test). Margin status had no impact on survival or freedom from distant metastasis; 63 patients who originally had positive or indeterminate margins were re-excised. Two of 7 with positive margins after re-excision versus 1/56 rendered margin negative had a local recurrence. CONCLUSIONS: The authors recommend re-excision for patients with positive margins because of improved local control of those rendered margin negative and identification of those patients at high risk for local failure (those who remain positive after re-excision). Because margin status impacts on local control, tumor margins after conservation surgery should be accurately determined in all patients.

Adult↗
PubMed1993

Alpha-blocking treatment with alfuzosin in symptomatic benign prostatic hyperplasia: comparative study with prazosin. The PRAZALF Group.

Alfuzosin, a selective alpha 1-adrenoceptor antagonist which is effective in the symptomatic treatment of benign prostatic hyperplasia (BPH), was compared with prazosin, another drug commonly used for the same purpose. After a 1-week placebo run-in period, 103 patients with day-time frequency > or = 7 or nocturia > or = 2 and peak flow rate < 15 ml/s were randomised to receive either alfuzosin (2.5 mg tid) or prazosin (2 mg bid) for 3 weeks, with a gradual dose increase during the first week, in a double-blind, parallel group, multicentre study. Voiding symptoms, assessed on the basis of the Boyarsky scale and a micturition diary, were significantly improved in both groups, as were urinary flow rates. However, neither the clinical improvement nor the increase in flow rates differed significantly between the 2 groups. The peak flow rate increased similarly with alfuzosin (2.6 +/- 0.6 ml/s) and prazosin (2.9 +/- 0.7 ml/s); the mean flow rate and voided volume increase tended to be more marked with alfuzosin (30 and 22.2% respectively) than with prazosin (20.6 and 6.5%). Clinical safety was good in both groups. All 4 adverse events in the prazosin group but only 1 of the 4 adverse events in the alfuzosin group were related to a decrease in blood pressure. It was concluded that alfuzosin was at least as effective as prazosin in the treatment of symptomatic patients with BPH and the incidence of adverse events related to their vasodilatory properties was lower with alfuzosin.

Adrenergic alpha-Antagonists↗
PubMed1992

Outbreaks of summer rotavirus linked to laboratory practices. The National Rotavirus Surveillance System.

In temperate regions rotavirus diarrhea is a disease of the cooler months of the year, but little is known about its patterns in the summer. We report on the first year of national surveillance of rotavirus, during which we actively investigated patterns of summer activity. We obtained data on rotavirus testing from 85 laboratories in 48 states, conducted a survey of their testing practices and retested for confirmation positive specimens from laboratories reporting high rates of positivity during the summer. During 1989 participating laboratories reported 4011 specimens tested for rotavirus during July and August, of which 436 (11%) were said to be positive. Most laboratories reported low rates of positivity during these months (median percent positive, 3), but five had very high rates of summer positivity (> 30%). These five laboratories were geographically separated, and neighboring laboratories showed little rotavirus activity. Positive specimens submitted by four of these centers with high rates of summer rotavirus could not be confirmed. A survey of laboratory methods found one commercial assay (TestPack) and two laboratory practices (failure to use controls and involvement of more than six technicians in the testing process) to be associated with high rates of summer positivity. Moderate rates of positivity (11 to 30%) were fond frequently in the southwest during July and August; reference testing of specimens from these laboratories confirmed positivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Laboratory Techniques↗