Biomedical subjects
Publications and source records attributed to D J Cook.
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OBJECTIVE: To identify the extent to which meta-analyses currently include unpublished data and whether editors, meta-analysts, and methodologists believe unpublished material should be included. DESIGN: This article describes two related studies: a literature review and a cross-sectional survey. SAMPLE SELECTION: For the literature review, we identified all articles indexed by the key word meta-analysis from January 1989 to February 1991 and determined whether unpublished material had been searched for, obtained, and included in the meta-analyses. For the cross-sectional survey, we surveyed authors of these meta-analyses, authors of articles addressing methodological issues in meta-analysis published during the same period, and editors of journals in which both types of articles were published. INTERVENTION: We asked the respondents about their attitudes concerning inclusion of unpublished data and publication of articles from which data had previously been included in a scientific overview. MAIN OUTCOME MEASURES: Inclusion of unpublished data and opinions about whether unpublished material should be included in overviews and whether prior inclusion of data in an overview should bear on publication. RESULTS: Of 150 meta-analyses, 46 (30.7%) included unpublished data in their primary analysis. Of authors surveyed, 85% responded. Of the meta-analysts and methodologists, 77.7% felt that unpublished material should definitely or probably be included in scientific overviews; this was true of 46.9% of the editors. A total of 86.4% of the meta-analysts and methodologists and 53.2% of the editors felt that inclusion of data in a prior overview should have no bearing on full publication of original research. CONCLUSION: While inclusion of unpublished data in scientific overviews remains controversial, most investigators directly involved in meta-analysis believe that unpublished data should not be systematically excluded. The most valid synthesis of available information will result when meta-analysts subject published and unpublished material to the same rigorous methodological evaluation and present results with and without unpublished sources of data.
OBJECTIVE: To learn about the physical, emotional, and social limitations experienced by postmenopausal women who have back pain due to vertebral fractures resulting from osteoporosis. METHODS: We conducted a cross-sectional survey of female patients with persistent pain due to vertebral fractures. RESULTS: Respondents had a mean (+/- SD) bone density of 0.87 +/- 0.13 gm/cm2 and a mean (+/- SD) of 2.84 +/- 2.18 fractures. Disability was identified in pain, movement, activities of daily living, and emotion. There was a poor correlation between quality of life and findings on radiography or densitometry. CONCLUSION: To evaluate the effects of osteoporosis on a patient's functional status, direct questioning is required.
OBJECTIVE: To examine the relationship between enteral nutrition (EN) and infection in the critically ill. SETTING: Computerized search of published research and review of relevant reference lists. STUDY SELECTION: 151 citations were reviewed and 39 articles met selection criteria. Primary studies were included if they evaluated EN in critically ill humans and its effect on infectious morbidity and mortality. MEASUREMENTS AND RESULTS: Relevant data were abstracted on the timing and impact of EN on morbidity, the optimal route of administration, composition and pH of EN, and bacterial contamination of EN. The evidence from human studies that EN, particularly early EN, results in reduced septic morbidity as compared to parenteral nutrition is limited to small, unblinded studies with non-rigorous definitions of pneumonia. There is no evidence to support a preference of feeding into the stomach versus the small bowel. The addition of fish oil, arginine, glutamine and fiber to enteral feeds has a variable impact on survival in animal models; there are no trials in critically ill patients that demonstrate a reduction in infectious morbidity and mortality. Acidification of enteral nutrition results in decreased bacterial colonization of the stomach in critically ill patients. Bacterial contamination of enteral nutrition is an important source of infection. CONCLUSIONS: Evidence from experimental data in critically ill patients suggests that enteral nutrition may have a favourable impact on gastrointestinal immunological function and infectious morbidity.
We wished to determine the extent to which respondents provided the same answers to a health-related quality of life (HRQL) questionnaire in self- and interviewer-administered forms. One hundred and fifty patients with asthma who were symptomatic or required treatment at least once a week, and had airway hyperresponsiveness to methacholine aerosol (PC20 < 8.0 mg/ml) participated. Patients completed a 152-item HRQL questionnaire in both interviewer and self-administered forms, separated by a 2-week interval, the order determined by random allocation. The percentage of items endorsed by the self-administered approach was significantly higher than that of the interviewer-administered approach overall (46.9 vs 35.8%) (p < 0.0001). The difference was consistent across all six domains; the absolute difference in the proportion of items endorsed varied from 8.9 to 12.3%. The intraclass correlations for the proportion of subjects endorsing an item was 0.84. Self- and interviewer-administered questionnaires yield very similar results in discriminating between subjects, but the self-administered version shows systematically greater HRQL impairment.
Although the quality of health reporting has been criticized for being unscientific, evaluations of health care reporting have been limited by the lack of a reliable and credible measure of scientific quality. We developed an index of scientific quality (ISQ) for health-related news reports and tested its reliability and sensibility. Items were generated from a survey of the literature and experts in research methodology. Items that were unclear, confusing or discriminated poorly between articles of high and low scientific quality were revised or deleted in an iterative process wherein potential criteria were independently applied to samples of 5 to 15 articles by 6 raters. To test the reliability of the final criteria 60 articles were drawn from three sampling frames: newspapers, magazines, and professional journals. Articles were intentionally selected to obtain a wide range of quality and topics. Two categories of raters were used: research assistants and physicians with research training. All 6 raters assessed all 60 articles. The sensibility of the index was tested by a questionnaire with 13 items related to face validity and content validity as well as other aspects of sensibility. The questionnaire was completed by 20 researchers and 13 health and science writers. The final ISQ includes 7 items that address the extent to which a report allows readers to draw conclusions about the applicability, validity and practical importance of the information that is reported. Chance corrected agreement (kappa) among all 6 raters for overall scientific quality was 0.62 (SE 0.02). The index was found to be sensible with only one major problem, the need for judgment in making ratings. While some degree of subjectivity appears to be inevitable in rating the scientific quality of health reports, the ISQ is acceptable reliable and credible and should be useful for evaluating and improving the scientific quality of health reporting.
BACKGROUND: Ketamine exerts both an indirect, positive inotropic effect and a direct, negative inotropic effect in isolated ferret ventricular myocardium. This negative inotropic effect becomes apparent after inactivation of the sympathetic neuroeffector junction. The aim of this study was to investigate the mechanisms of ketamine's intrinsic negative inotropic effect. METHODS: The authors analyzed the effects of ketamine after beta-adrenoceptor blockade on variables of contractility and relaxation, and on the free intracellular Ca++ transient detected with the Ca(++)-regulated photoprotein aequorin. Ketamine's effects were also evaluated in a preparation in which the sarcoplasmic reticulum (SR) function was impaired by ryanodine, and in frog ventricular myocardium in which the SR is poorly developed. RESULTS: Ketamine at concentrations > or = 3.3 x 10(-5) M decreased contractility and the amplitude of the intracellular Ca++ transient. After inactivation of sarcoplasmic reticulum Ca++ release with 10(-6) M ryanodine, a condition in which myofibrillar activation depends almost exclusively on transsarcolemmal Ca++ influx, ketamine caused a decrease in contractility and in the amplitude of the intracellular Ca++ transient, and ketamine's relative negative inotropic effect was not different from that in control muscles not exposed to ryanodine. Furthermore, > or = 10(-4) M ketamine decreased contractility in frog ventricular myocardium, a species that is almost entirely dependent on transsarcolemmal Ca++ influx for its myofibrillar activation. CONCLUSIONS: These findings indicate that the direct negative inotropic effect of ketamine results from a decrease in intracellular Ca++ availability with no changes in myofibrillar Ca++ sensitivity. At least part of ketamine's action is caused by inhibition of transsarcolemmal Ca++ influx.
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Tumor necrosis factor (TNF alpha), both by direct action and by trafficking cells of the immune system, is implicated in cardiopulmonary derangements and PMN-mediated microvascular injury associated with gram-negative sepsis. We examined the effects of pretreatment with a monoclonal antibody to TNF alpha on PMN function, hemodynamic derangements, and alveolar capillary membrane damage in a septic porcine model. Anti-TNF alpha profoundly improved hemodynamic consequences in this model. Reduction in PMN CD11/18 receptor expression, lung myeloperoxidase activity, and attenuation of peripheral neutropenia (all P < 0.05) indicate that pretreatment significantly reduced lung sequestration of PMNs seen in septic controls. In contrast, PMN oxygen radical (O2-) generation was not significantly different from unprotected septic animals. Despite the presence of circulating PMNs primed for O2- burst, alveolar capillary membrane damage, assessed by bronchoalveolar lavage protein content and arterial PO2 was markedly attenuated in the treatment group (P < 0.05). We conclude that anti-TNF alpha suppresses systemic hemodynamic actions of TNF alpha. Further, it prevents upregulation of PMN adhesion receptors inhibiting PMN/endothelial cell interaction. This prevents formation of a "microenvironment," protected from circulating oxidant scavengers, into which sepsis-activated PMNs release their toxic products. Pretreatment with anti-TNF alpha monoclonal antibody thus affords global protection in porcine Gram-negative sepsis.
The objective of this paper is to study the effect of amitriptyline on a young woman with symptoms of lightheadedness, palpitations, somnolence and fatigue. We conducted a single case (N-of-1) randomized trial including three pairs of treatment periods. Each pair included one four-week period when the patient was receiving amitriptyline and one four-week period when the patient was receiving placebo. The clinical setting was a secondary care internal medicine practice. During active treatment periods, amitriptyline was given in a dose of 100 mg each evening. Efficacy symptoms included lightheadedness, headaches and somnolence/fatigue. Side-effects of dry mouth and constipation were also monitored. Each symptom was rated on a seven point scale in which higher numbers denoted fewer symptoms. For the combined efficacy score, the mean difference in scores and the associated standard error was in favour of amitriptyline. The most profound effect was on sleepiness. These differences represent clinically important treatment effects. Dry mouth and constipation were worse on the active drug, but differences did not reach statistical significance. Our experience suggests the usefulness of N-of-1 randomized trials in outpatient medical practice, including psychiatric practice.
We evaluated ictal 99mtechnetium hexamethyl propylene-amine-oxime single-photon emission computed tomography (SPECT) in 22 children with electroclinical features of frontal lobe epilepsy (FLE). Ictal SPECT demonstrated unilateral frontal hyperperfusion in 20 of 22 children (91%) (one lobar, two frontocentral, six dorsolateral, six frontopolar, three orbitofrontal, one medial frontal, and one insula), concordant with electroclinical lateralization in 19 of 20 (95%). Hyperperfusion was evident in the ipsilateral basal ganglia in 16 of 22 (73%) and the contralateral cerebellum in 14 of 22 children (64%). Interictal SPECT showed unilateral, localized frontal hypoperfusion concordant with electroclinical lateralization in only two of 22 children (9%). Ictal SPECT localization to the frontocentral, media frontal, or dorsolateral regions was associated with asymmetric tonic posturing, contralateral head/eye deviation, and unilateral clonic jerking (p < 0.01). Ictal SPECT localization to the frontopolar or orbitofrontal regions was associated with vocalization, hyperventilation, truncal flexion, and complex gestural automatisms (p > or = 0.05). Ictal SPECT has the potential to (1) localize seizures in patients with intractable FLE, and (2) advance understanding of the in vivo anatomico-clinical relationships of frontal lobe seizures.
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Endoscopic hemostatic therapy for upper gastrointestinal bleeding is gaining widespread acceptance despite often conflicting results of randomized controlled trials. To examine the effect of endoscopic therapy in acute nonvariceal upper gastrointestinal hemorrhage, a meta-analysis was performed using a computerized search of the English-language literature and a bibliographic review. The methodology, population, intervention, and outcomes of each relevant trial were evaluated by duplicate independent review. Thirty randomized controlled trials evaluating hemostatic endoscopic treatment were identified. Endoscopic therapy significantly reduced rates of further bleeding (odds ratio, 0.38; 95% confidence interval, 0.32-0.45), surgery (odds ratio, 0.36; 95% confidence interval, 0.28-0.45), and mortality (odds ratio, 0.55; 95% confidence interval, 0.40-0.76). When analyzed separately, thermal-contact devices (monopolar and bipolar electrocoagulation and heater probe), laser treatment, and injection therapy all significantly decreased further bleeding and surgery rates. The reductions in mortality were comparable for all three forms of therapy, but the decrease reached statistical significance only for laser therapy. Further examination of subgroups indicated that endoscopic treatment decreased rates of further bleeding, surgery, and mortality in patients with high-risk endoscopic features of active bleeding or nonbleeding visible vessels. Rebleeding was not reduced by endoscopic therapy in patients with ulcers containing flat pigmented spots or adherent clots. Endoscopic hemostatic therapy provides a clinically important reduction in morbidity and mortality in patients with acute nonvariceal upper gastrointestinal hemorrhage.
Tricuspid valve stenosis in the setting of endocarditis is associated with a high morbidity. Diagnostic approaches incorporate a high clinical index of suspicion, echocardiographic evidence, and inferences about hemodynamic data derived from pulmonary artery catheterization. As demonstrated by the case presented herein, inadequate initial evaluation of right-sided pressures delayed the diagnosis and treatment of prosthetic tricuspid valve stenosis.
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Our objective was to determine the extent to which Intensive Care Unit (ICU) physicians are aware of charges for commonly used blood tests. We also wished to ascertain ICU physicians' perception of their motivation for, and appropriateness of, test ordering. Attending physicians and Internal Medicine residents in four university-affiliated ICUs in Hamilton were surveyed using a self-administered questionnaire. The response rate for the questionnaire was 91%. Physicians varied widely in their estimates of charges for ten laboratory tests. On average, residents tended to underestimate charges, while attending physicians sometimes underestimated, and sometimes overestimated. When all ten tests were considered, the mean estimates of the housestaff were lower than the ICU attending physicians (p < 0.001). Overall, attending estimates were 29.5% higher. Over 85% of physicians felt that too many blood tests were being performed. Physicians perceived that they pay insufficient attention to the risk of anemia and to issue of cost. Their feeling that test ordering in the ICU is excessive suggests that they may be open to modifying their practice. Given the large proportion of hospital resources allocated to the intensive care unit, interventions to decrease test ordering are warranted.