Showing papers by "McMaster University published in 1989"
TL;DR: An approach to elucidating the significance of changes in score in quality of life instruments by comparing them to global ratings of change is developed, and a plausible range within which the minimal clinically important difference (MCID) falls is established.
4,170 citations
TL;DR: The nonexperimental evidence that forms the recalled experiences of seasoned clinicians will tend to overestimate efficacy for the following reasons:.
1,369 citations
TL;DR: The midsagittal area of the corpus callosum was measured in its entirety and in seven subdivisions in a sample of 50 brains consecutively obtained from autopsies of individuals who had neuropsychological testing before death.
Abstract: The midsagittal area of the corpus callosum was measured in its entirety and in seven subdivisions in a sample of 50 brains consecutively obtained from autopsies of individuals who had neuropsychological testing before death. A 12-item test of hand preference was used as an index of the pattern of interhemispheric functional asymmetry. Callosal size was analysed for two factors: hand preference, classified as consistent-right-hand preference (CRH) versus non consistent-right-hand preference, and sex. The group of nCRH (n = 18) was found to have a larger overall callosal area, with the greatest difference occurring in the posterior body segments, especially the isthmus. The isthmus probably includes interhemispheric fibres from posterior parietal and superior temporal cortex which involves cortical regions related to functional asymmetry. The results of variation in callosal morphology are discussed as part of a possible substrate of functional asymmetry and due to variation in axonal elimination in early brain development. Sex differences were found in several aspects of callosal anatomy. (1) The difference between hand groups in the posterior body occurred in interaction with sex:handedness was a factor in callosal size in males (n = 15), but not in females (n = 35). This result is consistent with the general hypothesis of females having less clear lateralization than males. (2) Females did not have a larger overall callosum or a larger splenium, either in absolute size or size proportional to brain weight. The latter measure was considered since callosal area correlated with cerebrum weight (r = 0.48). In contrast, female of both hand groups were found to have a larger proportional isthmus compared to CRH males. (3) Of all callosal regions, only the genu and a part of the anterior body were found to be larger in absolute size in males than females. (4) Callosal size decreased with chronological age in males, but not in females.
1,336 citations
TL;DR: It is concluded that guidelines for practice may predispose physicians to consider changing their behavior, but that unless there are other incentives or the removal of disincentives, guidelines may be unlikely to effect rapid change in actual practice.
Abstract: Guidelines for medical practice can contribute to improved care only if they succeed in moving actual practice closer to the behaviors the guidelines recommend. To assess the effect of such guidelines, we surveyed hospitals and obstetricians in Ontario before and after the release of a widely distributed and nationally endorsed consensus statement recommending decreases in the use of cesarean sections. These surveys, along with discharge data from hospitals reflecting actual practice, revealed that most obstetricians (87 to 94 percent) were aware of the guidelines and that most (82.5 to 85 percent) agreed with them. Attitudes toward the use of cesarean section were congruent with the recommendations even before their release. One third of the hospitals and obstetricians reported changing their practice as a consequence of the guidelines, and obstetricians reported rates of cesarean section in women with a previous cesarean section that were significantly reduced, in keeping with the recommendations (from 72.2 percent to 61.1 percent; P less than 0.01). The surveys also showed, however, that knowledge of the content of the recommendations was poor (67 percent correct responses). Furthermore, data on actual practice after the publication of the guidelines showed that the rates of cesarean section were 15 to 49 percent higher than the rates reported by obstetricians, and they showed only a slight change from the previous upward trend. We conclude that guidelines for practice may predispose physicians to consider changing their behavior, but that unless there are other incentives or the removal of disincentives, guidelines may be unlikely to effect rapid change in actual practice. We believe that incentives should operate at the local level, although they may include system-wide economic changes.
1,231 citations
TL;DR: The Inflammatory Bowel Disease Questionnaire shows promise as a measure of health status for clinical trials in IBD, and responsiveness appeared greater in patients with ulcerative colitis than in those with Crohn's disease.
1,111 citations
TL;DR: Utilities and quality-adjusted life years (QALYs) are reviewed, with particular focus on their use in technology assessment and their interrelationship.
Abstract: Utilities and quality-adjusted life years (QALYs) are reviewed, with particular focus on their use in technology assessment. This article provides a broad overview and perspective on these two techniques and their interrelationship, with reference to other sources for details of implementation. The historical development, assumptions, strengths/weaknesses, and applications of each are summarized. Utilities are specifically designed for individual decision-making under uncertainty, but, with additional assumptions, utilities can be aggregated across individuals to provide a group utility function. QALYs are designed to aggregate in a single summary measure the total health improvement for a group of individuals, capturing improvements from impacts on both quantity of life and quality of life--with quality of life broadly defined. Utilities can be used as the quality-adjustment weights for QALYs; they are particularly appropriate for that purpose, and this combination provides a powerful and highly useful variation on cost-effectiveness analysis known as cost-utility analysis.
837 citations
TL;DR: The Canadian American Ticlopidine Study (CATS) as discussed by the authors is a randomized, double-blind, placebo-controlled trial to assess the effect of ticloopidine (250 mg twice daily) in reducing the rate of subsequent occurrence of stroke, myocardial infarction, or vascular death in patients who have had a recent thromboembolic stroke.
824 citations
TL;DR: Normality was shown to encompass radiological features often considered pathological which overlap with reported pathological states, and the formation of rectocoeles during defecation was a very common finding in women.
Abstract: Forty seven healthy young volunteers underwent defecographic examination to determine the range of normal findings. Normality was shown to encompass radiological features often considered pathological. These features included broad ranges of anorectal angle and pelvic floor descent which overlap with reported pathological states. Furthermore, the formation of rectocoeles during defecation was a very common finding in women. Finally, a subgroup of the volunteers had marginal anorectal function. The marginal anorectal function and certain radiological findings such as rectocoeles or intussusceptions may predispose to later problems, or contribute to clinical problems when combined with other factors such as dietary fibre deficiency. The radiological findings raise a number of questions with respect to different aspects of the functioning of the continence and defecation mechanisms.
720 citations
TL;DR: There were no significant differences in the prevalence of ADDH by age or urban-rural status, but the disorder was significantly more common in boys than in girls.
Abstract: The objective of this paper is to present data from the Ontario Child Health Study on the prevalence of attention deficit disorder with hyperactivity (ADDH). The overall prevalence of ADDH was 9.0% in boys and 3.3% in girls. There were no significant differences in the prevalence of ADDH by age or urban-rural status, but the disorder was significantly more common in boys than in girls. The prevalence of various subtypes of ADDH was also explored: attention deficit with and without hyperactivity, situational vs pervasive ADDH, and ADDH with and without other disorders. The clinical implications of these findings are discussed.
567 citations
TL;DR: A number of examples show that this is not necessarily so as discussed by the authors, and that resources held in common will not always be over-expoited, the "tragedy of the commons".
Abstract: Conventional wisdom holds that resources held in common will invariably be overexploited — the "tragedy of the commons". A number of examples show that this is not necessarily so.
530 citations
TL;DR: Groups of aphasic patients and their spouses generated a series of communication situations that they felt were important in their day-to-day life and these data were used to evaluate the psychometric properties of the Communicative Effectiveness Index (CETI) as a measure of change in functional communication ability.
Abstract: Groups of aphasic patients and their spouses generated a series of communication situations that they felt were important in their day-to-day life. Using criteria to ensure that the situations were...
TL;DR: The observed high degree of homology between human P1 and mycobacterial antigen also suggests the possible involvement of this protein in certain autoimmune diseases.
Abstract: The complete cDNA for a human mitochondrial protein designated P1, which was previously identified as a microtubule-related protein, has been cloned and sequenced. The deduced amino acid sequence of P1 shows strong homology (40 to 50% identical residues and an additional 20% conservative replacements) to the 65-kilodalton major antigen of mycobacteria, to the GroEL protein of Escherichia coli, and to the ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) subunit binding protein of plant chloroplasts. Similar to the case with the latter two proteins, which have been shown to act as chaperonins in the posttranslational assembly of oligomeric protein structures, it is suggested that P1 may play a similar role in mammalian cells. The observed high degree of homology between human P1 and mycobacterial antigen also suggests the possible involvement of this protein in certain autoimmune diseases.
TL;DR: The authors show that QALYs, being a health status index, do not stem directly from theindividual's utility function and thus only partly reflect the individual's true preferences, and describe an alternative measure of outcome, the healthy-years equiv alent (HYE), which combines outcomes of both morbidity and mortality and thus can serve as common unit of measure for all programs.
Abstract: Decisions about medical treatments and the settings of health programs are not purely technical, but also involve issues of value such as the evaluation of trade-offs between quality of life (morbidity) and quantity of life (mortality). The most commonly used measure of outcome in such cases is the quality-adjusted life year (QALY). The authors show that QALYs, being a health status index, do not stem directly from the individual's utility function and thus only partly reflect the individual's true preferences. This might lead to the choice of the nonpreferred alternative due to the misrepresentation of the individual's preferences. Two examples illustrate this claim. An alternative measure of outcome, the healthy-years equivalent (HYE), is described. This measure stems directly from the individual's utility function and thus fully reflects his/her preferences. It combines outcomes of both morbidity and mortality and thus can serve as common unit of measure for all programs, allowing comparisons across programs. Different ways of measuring the HYE are discussed.
TL;DR: Data from two studies are presented which clarify the relationship between the responsiveness and validity of instruments designed to measure health status in clinical trials and support the reproducibility, validity, and responsiveness of the questionnaire.
TL;DR: A theoretical basis for scheduling mixed-model assembly lines and Just-In-Time JIT production systems is developed, and new scheduling algorithms and heuristics are presented.
Abstract: Mixed-model assembly lines are used to produce many different products without carrying large inventories. The effective utilization of these lines requires that a schedule for assembling the different products be determined. For Just-In-Time JIT production systems, which require producing only the necessary products in the necessary quantities at the necessary times, the objective is to keep a constant rate of usage of all parts used by the line. This is called levelling or balancing the schedule. This paper develops a theoretical basis for scheduling these systems, and presents new scheduling algorithms and heuristics.
TL;DR: Mast cell/nerve associations have been recorded in several publications; however, the human gastrointestinal tract has received little attention, and mucosal samples from small bowel, appendix, and large bowel were studied to provide a microanatomic basis for potential communication between nerves and mast cells in the humanintestinal mucosa.
TL;DR: Numerical solution methods surveyed here will be of much use to practicing computational/finite element/structural engineers working in the area of dynamics of structures.
Journal Article•
TL;DR: Although accurate measurement of quality of life in randomized trials is now feasible it is still not widely done, and investigators can choose generic or specific instruments according to the purpose and the focus of their trial.
Abstract: Measurement of quality of life is becoming increasingly relevant to controlled clinical trials. Two basic types of instrument are available: generic instruments, which include health profiles and utility measurements based on the patient's preferences in regard to treatment and outcome; and specific instruments, which focus on problems associated with individual diseases, patient groups or areas of function. The two approaches are not mutually exclusive; each has its strengths and weaknesses and may be suitable under different circumstances. We surveyed 75 randomized trials published in three medical journals in 1986 and categorized them according to the importance of quality of life as a measure of outcome and the extent to which quality of life was actually measured. Although a number of the investigators used quality-of-life instruments in a sophisticated manner, in only 10 of 55 trials in which the measurement had been judged to be crucial or important were instruments with established validity and responsiveness used. We conclude that although accurate measurement of quality of life in randomized trials is now feasible it is still not widely done. Using the framework we have outlined, investigators can choose generic or specific instruments according to the purpose and the focus of their trial.
TL;DR: The authors develop a new measure of subjective health status for patients with heart failure that shows moderate correlations with patient global ratings, walk test scores, and clinical assessments of heart failure, and conclude that it may be useful for measuring health status in clinical trials in heart failure.
Abstract: The authors developed a new measure of subjective health status for patients with heart failure. Eighty-eight patients with heart failure were asked about the impact of their condition on 123 items related to physical and emotional function. The most frequently chosen and important items were included in a 16-item Chronic Heart Failure Questionnaire (CHQ) that examines dyspnea during daily activities, fatigue, and emotional function. The CHQ was tested in a controlled trial of digoxin in heart failure patients in sinus rhythm. When administered serially to 25 patients in the run-in phase of the trial, the CHQ proved reproducible. Subsequently, CHQ results distinguished those who reported improvement or deterioration from those who did not. The CHQ showed moderate correlations with patient global ratings, walk test scores, and clinical assessments of heart failure. The authors conclude that the CHQ may be useful for measuring health status in clinical trials in heart failure.
TL;DR: The risk of injury was associated with increased running mileage but was relatively unassociated with other aspects of training, such as usual pace, usual running surface, hill running, or intense training.
Abstract: • A cohort of 1680 runners was enrolled through two community road race events and monitored during a 12-month follow-up period for the occurrence of musculoskeletal injuries. Fortyeight percent of the runners experienced at least one injury, and 54% of these injuries were new; the remainder were recurrences of previous injuries. The risk of injury was associated with increased running mileage but was relatively unassociated with other aspects of training, such as usual pace, usual running surface, hill running, or intense training. Injury rates were equal for all age-sex groups and were independent of years of running experience. Runners injured in the previous year had approximately a 50% higher risk for a new injury during follow-up. ( Arch Intern Med . 1989;149:2561-2564)
TL;DR: ESR dating has been systematically applied in earth sciences and archaeology since 1975 when Ikeya dated a stalactite from the Akiyoshi cave in Japan as discussed by the authors, which allows the age assessment of heated ceramics, volcanic rocks, intrafault material, or windblown sediments.
TL;DR: The authors found that memory predictions are implicit judgments of how easily the item is processed while answering the predictive question, i.e., if items are processed easily because of factors that also cause memory to succeed, predictions are accurate; if the factors that cause easy processing are irrelevant for memory, prediction are less accurate.
TL;DR: It is concluded that heparin administered subcutaneously in a dosage of 12,500 unitsevery 12 hours to patients with acute anterior transmural myocardial infarction is more effective than a lower dosage (5000 units every 12 hours) in preventing left ventricular mural thrombosis.
Abstract: We performed a double-blind randomized trial comparing high doses of subcutaneous heparin (12,500 units every 12 hours) with low doses (5000 units every 12 hours) for 10 days in the prevention of left ventricular mural thrombosis in 221 patients with acute anterior myocardial infarction. Left ventricular mural thrombosis was observed by two-dimensional echocardiography on the 10th day after infarction in 10 of 95 patients (11 percent) in the high-dose group and in 28 of 88 patients (32 percent) in the low-dose group (P = 0.0004). One patient in the high-dose group and four in the low-dose group had nonhemorrhagic strokes (P = 0.17). One patient in the low-dose group had a fatal pulmonary embolism. There was no difference in the frequency of hemorrhagic complications, which occurred in six patients in the high-dose group and four in the low-dose group. The mean (±SEM) plasma heparin concentration was 0.18±0.017 U per milliliter in the high-dose group and 0.01 ±0.005 U per milliliter in the low-dos...
TL;DR: A role for the central nervous system as a functional effector of mast cell function in the allergic state is supported, and animals reexposed to only the audiovisual cue released a quantity of protease not significantly different from animals re exposed to both the cue and the antigen.
Abstract: Antigen (egg albumin) injections, which stimulate mucosal mast cells to secrete mediators, were paired with an audiovisual cue. After reexposure to the audiovisual cue, a mediator (rat mast cell protease II) was measured with a sensitive and specific assay. Animals reexposed to only the audiovisual cue released a quantity of protease not significantly different from animals reexposed to both the cue and the antigen; these groups released significantly more protease than animals that had received the cue and antigen in a noncontingent manner. The results support a role for the central nervous system as a functional effector of mast cell function in the allergic state.
TL;DR: It is suggested that the operations for eliciting stimulus-induced eating in sated subjects may be useful for future examinations of the psychological properties of craving.
TL;DR: The results indicate that the prevalence and pattern of correlates of the individual disorders differ in important ways by informant, suggesting that the factors that influence assessments provided by informants from different contexts need to be understood before combining information from them to arrive at singular classifications.
Abstract: Data from the Ontario Child Health Study were used to examine the prevalence and selected correlates of conduct disorder, hyperactivity, emotional disorder, and somatization in children 4 to 16 years of age by informant (parent and teacher for children 4 to 11, and parent and youth for children 12 to 16). The results indicate that the prevalence and pattern of correlates of the individual disorders differ in important ways by informant. This suggests that we need to understand the factors that influence assessments provided by informants from different contexts (e.g., parents and teachers) before combining information from them to arrive at singular classifications.
TL;DR: The results of the study indicate that a small percentage of nonretarded autistic children can be expected to recover to a substantial degree.
Abstract: It is well known that IQ is an important prognostic variable in the outcome of autistic children. There are, however, very few data available on the outcome of nonretarded autistic children as adults. We identified 16 such probands from records and followed them up between 11 and 27 years since discharge from a center specializing in the assessment of autistic children. There were 12 males and 4 females, average age was 26, and mean IQ was 92 (range 68–110). Although the majority were functioning poorly in terms of occupational-social outcome and psychiatric symptoms, a surprising number (4) had a very good outcome and might be considered recovered. The severity of early autistic behavior was a poor predictor of outcome, but neuropsychologic measures of nonverbal problem solving were highly correlated with outcomes. The results of the study indicate that a small percentage of nonretarded autistic children can be expected to recover to a substantial degree.
TL;DR: The effects of the D-2 agonist quinpirole on forward progression, and on vertical and lateral movements, were measured and it was suggested that the biphasic effect may reflect two independent actions of the drug, possibly on activity in the nucleus accumbens.
TL;DR: Model calculations of source partitioning based on the carbon-14 data, CH4 concentrations, and δ13C in CH4 indicate that 21 � 3% of atmospheric CH4 was derived from fossil carbon at the end of 1987, and data indicate that pressurized water reactors are an increasingly important source of 14CH4.
Abstract: Measurements of carbon-14 in small samples of methane from major biogenic sources, from biomass burning, and in "clean air" samples from both the Northern and Southern hemispheres reveal that methane from ruminants contains contemporary carbon, whereas that from wetlands, pat bogs, rice fields, and tundra is somewhat, depleted in carbon-14. Atmospheric (14)GH(4) seems to have increased from 1986 to 1987, and levels at the end of 1987 were 123.3 +/- 0.8 percent modern carbon (pMC) in the Northern Hemisphere and 120.0 +/- 0.7 pMC in the Southern Hemisphere. Model calculations of source partitioning based on the carbon-14 data, CH(4) concentrations, and delta(13)C in CH(4) indicate that 21 +/- 3% of atmospheric CH(4) was derived from fossil carbon at the end of 1987. The data also indicate that pressurized water reactors are an increasingly important source of (14)CH(4).