Biomedical subjects

T To

Publications and source records attributed to T To.

At least 37 records · Page 2Linked to original sources

PubMed1997

Physicians' opinions about decision aids for patients considering systemic adjuvant therapy for axillary-node negative breast cancer.

PURPOSE: To examine variations in physicians' opinions about the appropriateness and content of decision aids for women with breast cancer and criteria for their evaluation. METHODS: Cross-sectional survey of all 144 Ontario oncologists by Dillman's mailed survey design. The response rate was 87%. RESULTS: The predominant current practice pattern was to spontaneously inform patients about the treatment recommendations, degree of certainty regarding the recommendations, treatment regime, benefits and side effects. Most respondents (94%) endorsed patient decision aids, particularly when there was high uncertainty about providing adjuvant treatment. Over three-quarters endorsed measuring the following outcomes of decision aids: patients' clarity of trade-offs involved (e.g. survival vs. side effects); comprehension of treatment alternatives, risks and benefits; accuracy of expectations; decision satisfaction; anxiety; commitment to the decision; length of time to complete the decision aid; and decision uncertainty. The least support was for the use of the decision itself as an outcome measure. CONCLUSIONS: There is considerable consensus regarding the indications for, content and criteria for evaluating decision aids which should be considered when developing aids relevant to the needs of clinicians and patients.

Adult↗

PubMed1997

The Canadian National Breast Screening Study: update on breast cancer mortality.

The Canadian National Breast Screening Study (CNBSS), conducted on women age 40-49, was designed to evaluate the efficacy of combined annual mammography and physical examination of the breasts in reducing breast cancer mortality in comparison to usual care (UC) controls. From January 1980 through March 1985, 25,214 women were individually randomized to the mammography/physical exam (MP) arm and 25,216 to the UC. The integrity of the randomization has been reviewed and confirmed to be unbiased. During an average, follow-up of 10.5 years from entry (range: 8.75-13 years), 82 women died from breast cancer in the MP arm and 72 in the UC, for a rate ratio of 1.14 (95% confidence interval: 0.83-1.56). All-cause mortality was almost identical comparing the two groups; the nonsignificant excess of breast cancer deaths in the MP arm was balanced by an excess of other cancer deaths in the UC arm.

Adult↗

PubMed1996

Leukemia following occupational exposure to 60-Hz electric and magnetic fields among Ontario electric utility workers.

In a nested case-control study of 1,484 cancer cases and 2,179 matched controls from a cohort of 31,543 Ontario Hydro male employees, the authors evaluated associations of cancer risk with electric field exposure and reevaluated the previously reported findings for magnetic fields. Pensioners were followed from January 1, 1970, and active workers (including those who left the corporation) from January 1, 1973, with both groups followed through December 31, 1988. Exposures to electric and magnetic fields and to potential occupational confounders were estimated through job exposure matrices. Odds ratios were elevated for hematopoietic malignancies with cumulative electric field exposure. After adjustment, the odds ratio for leukemia in the upper tertile was 4.45 (95% confidence interval (CI) 1.01-19.7). Odds ratios were also elevated for acute nonlymphoid leukemia, acute myeloid leukemia, and chronic lymphoid leukemia. For cumulative magnetic field exposure, there were similar elevations that fell with adjustment. Evaluation of the combined effect of electric and magnetic fields for leukemia showed significant elevations of risk for high exposure to both, with a dose-response relation for increasing exposure to electric fields and an inconsistent effect for magnetic fields. There was some evidence of a nonsignificant association for brain cancer and benign brain tumors with magnetic fields. For lung cancer, the odds ratio for high exposure to electric and magnetic fields was 1.84 (95% CI 0.69-4.94).

Adult↗

PubMed1996

Immunohistochemical localization of ORL-1 in the central nervous system of the rat.

A novel member of the opioid receptor family (ORL-1) has been cloned from a variety of vertebrates. ORL-1 does not bind any of the classical opioids, although a high affinity endogenous agonist with close homology to dynorphin has recently been identified. We have generated a monoclonal antibody to the N-terminus of ORL-1 to map areas of receptor expression in rat central nervous system (CNS). Intense and specific immunolabeling was observed in multiple areas in the diencephalon, mesencephalon, pons/medulla, and spinal cord. In the telencephalon, intense labeling was observed in the neuropil throughout layers II-V in the neocortex, the anterior olfactory nuclear complex, the pyriform cortex, the CA1-CA4 fields and dentate gyrus of the hippocampus, and in many of the septal and basal forebrain areas. In contrast to other members of the opioid receptor family, light labeling for ORL-1 was observed in telencephalic areas such as caudate-putamen. In the cerebellum, ORL-1 immunoreactivity was only observed in the deep nuclei. Throughout the CNS the majority of labelling was localized to fiber processes and fine puncta, although labeled scattered perikarya were observed in a few brain areas such as the hilus dentate in the hippocampus and some nuclei in the brainstem and spinal cord. The present mapping study is consistent with the reported distribution of ORL-1 mRNA and provides the first immunohistochemical report on anatomical and cellular distribution of ORL-1 receptor in the rat CNS.

Animals↗

PubMed1996

Tumor angiogenesis as a predictor of recurrence in stage Ib squamous cell carcinoma of the cervix.

OBJECTIVE: To explore the possibility of using histologic microvessel count of sections from the tumor to predict recurrence of stage Ib squamous cell carcinoma of the cervix. METHODS: Tumor sections from 22 patients (11 patients free of disease after 3 years and 11 patients with recurrence) were stained histoimmunochemically for factor VIII-related antigens. Vessel counting in the most active area of angiogenesis was performed by two pathologists on a x 200 microscopic field (0.739 mm2) without knowledge of the patient's' outcome. To predict recurrence, vessel count was compared with age, tumor size, tumor grade, lymph-vascular invasion, duration of follow-up, and type of therapy. RESULTS: Only high microvessel count (mean 19.9, range 7-43, versus mean 30.1, range 17-78; P < .05) and tumor size (mean 2.84 cm, range 1-4.2, versus mean 4.11 cm, range 2.2-6; P < .05) were independent factors predicting recurrence. CONCLUSION: High microvessel count in tumors may be used to predict recurrence in stage Ib squamous cell carcinoma of the cervix.

Adult↗

PubMed1996

Respiratory function after cardiac surgery.

STUDY OBJECTIVE: Cardiac surgery is complicated by decreased postoperative respiratory muscle strength and spirometry with accompanying increased atelectasis. The specific respiratory symptoms attributable to these physiologic changes are unknown, and this study looked at the symptoms and underlying physiology. DESIGN: Convenience sampling of observational cohort. SETTING: Tertiary care university hospital. PATIENTS: One hundred thirty-eight patients undergoing elective surgery were enrolled. INTERVENTIONS: Changes from admission to 8-week postoperative values in atelectasis, pleural effusions, spirometry (forced vital capacity and forced expiratory volume in one second), and respiratory muscle strength (negative inspiratory pressure) were measured. These physiologic changes were compared with changes in respiratory symptoms of cough, wheeze, phlegm, and dyspnea on walking up a slight hill noted from admission to 8-week follow-up by stepward logistic regression. MEASUREMENTS AND RESULTS: Spirometry and negative inspiratory pressure decreased and atelectasis increased from admission to discharge. These disturbances had only incompletely resolved at 8-week follow-up. Some patients reported fewer symptoms of cough (11%), phlegm (9%), wheeze (35%), and dyspnea (46%) at 8 weeks follow-up. Other patients reported increased symptoms of cough (15%), phlegm (10%), wheeze (6%), and dyspnea (4%) at 8 weeks follow-up. Residual atelectasis at 8 weeks was predictive of fewer symptoms of dyspnea (odds ratio [OR] 0.335, p = 0.199; 95% confidence interval [CI] 0.188, 0.597), increased symptoms of dyspnea (OR 855, p = 0.006; 95% CI 6.6, 11052), and increased symptoms of cough (OR 260, p = 0.023; 95% CI 2.13, 31829). Negative inspiratory pressure at 8 weeks was predictive of fewer symptoms of dyspnea (OR 1.05, p = 0.032; 95% CI 1.02, 1.09) and increased symptoms of wheeze (OR 0.7, p = 0.45; 95% CI 0.533, 0999). Forced vital capacity at 8 weeks was predictive of increased symptoms of wheeze (OR 0.005; p = 0.015; 95% CI 0.0060, 0.775). CONCLUSIONS: Postoperative changes in respiratory muscle strength and spirometry can persist up to at least 8 weeks postoperatively. Many patients report a change in respiratory symptoms of cough, phlegm, dyspnea, or wheeze. The change in respiratory symptoms at 8 weeks is correlated with residual respiratory muscle weakness, decrease in spirometry, and residual atelectasis.

Adult↗

PubMed1996

Trends and variations in the use of vascular surgery in Ontario.

OBJECTIVE: To measure changes over time in overall surgical rates and geographic rate variations for three major vascular procedures (abdominal aortic aneurysm repairs, peripheral vascular disease procedures and carotid endarterectomies). BACKGROUND: There is little research literature on population-based usage profiles of vascular procedures. The three procedures profiled were all subject to marked shifts in evidence or surgical opinions, raising the issue of the interplay between temporal trends and geographic variations in their use. METHODS: Based on Ontario's hospital discharge abstracts and census data, population-based usage rates were calculated by site of patient residence from 1981 to 1991. Extent of rate variation was summarized with the coefficient of variation, systematic component of variation and the adjusted-likelihood ratio chi2. Spearman rank correlations were also calculated to assess stability of county rankings for each procedure. RESULTS: The overall rates of peripheral vascular procedures and repair for abdominal aortic aneurysms fell 24% and increased 42% respectively. The overall rate of carotid endarterectomies dropped from 46/100,000 in 1981 to 20/100,000 in 1989, but by 1991 had increased to 37/100,000. Through the decade measures of variation fell minimally for all three procedures. CONCLUSION: Overall use of vascular procedures shifted in apparent response to new research evidence and technologies. Despite marked changes in surgical rates, the extent of geographic variation was stable, suggesting that differing factors influence overall surgical rates and geographic rate variations. Audit at the local level using primary clinical data is needed to understand why disparities in use persist.

Aortic Aneurysm, Abdominal↗

PubMed1996

A cohort study on childhood asthma admissions and readmissions.

BACKGROUND: Admissions to hospitals for childhood asthma seem to be increasing, even though admissions for other childhood conditions are decreasing. We studied admissions and readmissions for childhood asthma in Ontario in an attempt to uncover factors relating to the admission patterns. METHODS: Using the hospital discharge data from the Canadian Institute for Health Information, 28,646 children with diagnoses of asthma were identified from April 1, 1989, to March 31, 1992. RESULTS: The admission rates for asthma among children in Ontario showed a 14.8% decrease from 1987 to 1992. This decline was observed primarily in 5- to 17-year-olds. Younger children had a fourfold risk of hospital admission for asthma. In the 4 years studied, 10,427 children (36.4%) were readmitted at least once, representing 22,114 readmissions, 16,196 (73.2%) of which were for asthma. The 6-month probabilities of readmission for asthma were 20.0% (0- to 4-year-olds) and 11.7% (5- to 17-year-olds). The estimated relative risks (RRs) indicated that younger children had a significantly higher risk of readmission for asthma (RR, 1.38; 95% confidence interval, 1.30 to 1.46) or asthma-related causes (RR, 5.02; 95% confidence interval, 4.16 to 6.05). CONCLUSIONS: The observed increasing trend in admissions for asthma among children in the 1970s and 1980s leveled off in the early 1990s. The declining admission rates were largely caused by the lower admission rates among school-aged children from 5 to 17 years. The relatively high admission and readmission rates of preschool children are still a concern. Further research is necessary to examine factors that influence admissions for asthma among young children.

Adolescent↗

PubMed1996

Risk factors for breast cancer mortality among the National Breast Screening Study of Canada participants.

We studied the relationship between risk factor information and breast cancer mortality by means of a case control study, nested within the population of the National Breast Screening Study of Canada (NBSS). The characteristics of women aged 40-59 years, identified at the initial screen, who subsequently died of breast cancer up to 7 years from the initial screen, were compared with those of controls drawn from the same population. Among the factors evaluated in this study, number of live births and presence of symptoms in the breast revealed on direct questioning were found to be significantly related to breast cancer mortality. The results suggest a decrease in risk of dying of breast cancer associated with one or more live births (OR: 0.79, 95% CI: 0.68, 0.93), and an increase in risk of dying of breast cancer associated with symptoms in the breast revealed on direct questioning at the initial screen (OR: 2.01, 95% CI: 1.20, 3.37).

Adult↗

PubMed1995

Association between duration of neonatal hospital stay and readmission rate.

OBJECTIVE: A recent rapid decrease in the duration of neonatal hospital stay in Ontario, Canada, enabled us to study the association between healthy infants' age at neonatal hospital discharge and subsequent readmission rates. DESIGN: (1) Population-based and (2) single hospital-based retrospective studies. SETTING AND STUDY POPULATION: (1) A total of 920,554 healthy infants with a birth weight of 2500 gm or more, born in Ontario from 1987 to 1994. (2) Infants with a birth weight of 2500 gm or more, born during the same period, and readmitted before 15 days from home to the Hospital for Sick Children for jaundice or dehydration. MEASUREMENT: Duration of neonatal stay in the hospital and readmission rates were measured, and diagnostic codes were analyzed. Severity of illness was evaluated in infants readmitted to our hospital. RESULTS: In Ontario the mean length of stay decreased from 4.5 days to 2.7 days (p = 0.000), and the readmission rate during the first 2 weeks of life increased from 12.9 to 20.7 per 1000 (p = 0.000). Increased rates of readmission were most marked for jaundice and dehydration. The infants readmitted to our hospital had evidence of increased severity of illness as indicated by higher serum bilirubin and sodium concentrations. Two deaths occurred in infants with hypernatremic dehydration, one in 1992-1993 and another in 1993-1994. CONCLUSIONS: In Ontario, shorter neonatal hospital stay was associated with increased readmission rates for conditions that may not give rise to symptoms or signs on days 1 to 3 of life. In our hospital the severity of jaundice and dehydration in readmitted infants increased. The severity-of-illness data raise the question of whether shorter neonatal hospital stay of apparently healthy infants is always safe. Decisions to discharge infants should be based on rigorous evaluation of individual infants.

Analysis of Variance↗

PubMed1995

Postoperative physical therapy after coronary artery bypass surgery.

Coronary artery bypass surgery is frequently complicated by postoperative atelectasis. Although routinely prescribed, the efficacy of any specific chest physical therapy is not well established. We studied patients at a university center undergoing elective coronary artery bypass surgery. Based upon chest X-ray criteria at extubation, patients (n = 228) were classified as demonstrating greater or lesser degrees of atelectasis. Those with a lesser degree of atelectasis were randomized to receive either early mobilization or sustained maximal inflations (SMI). Those with greater a degree of atelectasis were separately randomized to receive either SMI or single-handed percussions (SSP). We found the extent of atelectasis at extubation did not predict the risk of developing pneumonia. Hospital stays and intensive care unit stays were similar regardless of treatment. Physical therapy costs were highest in the most labor-intensive therapy group (SSP). We conclude that postoperative respiratory dysfunction is common but does not commonly cause significant morbidity or prolong hospital stay. Adding SMI to patients with minimal atelectasis at extubation does not improve clinical outcomes. Similarly, adding SSP to patients with marked atelectasis does not improve outcomes over those obtained with SMI and early ambulation.

Aged↗

PubMed1995

Appropriateness of adjuvant systemic therapy for axillary node-negative breast cancer: a physician opinion survey.

PURPOSE: To examine variations in physicians' recommendations for systemic adjuvant therapy in the treatment of women with node-negative breast cancer (NNBC) and to determine factors used in making specific recommendations. MATERIALS AND METHODS: A questionnaire was sent by mail to all 149 Ontario physicians who actively treated breast cancer in 1993. The questionnaire described 48 clinical scenarios of women with NNBC, which included all possible combinations of the following factors: menopausal status, tumor size, hormone receptor status, histologic and nuclear grade, and lymphatic and/or vascular invasion. Respondents rated the appropriateness of administering tamoxifen, combination chemotherapy, or both tamoxifen and combination chemotherapy on a nine-point scale from extremely inappropriate to extremely appropriate. Respondent agreement and disagreement were tabulated for each scenario, and factors associated with specific treatment ratings were analyzed by logistic regression. RESULTS: The response rate was 87%. Agreement for the appropriateness of specific therapies was most evident where clinical trials have demonstrated efficacy, whereas disagreement was observed in scenarios in which support for a specific treatment is not available in the current literature. Relevant tumor- and patient-specific factors were used in decision-making; personal characteristics of the respondents had no statistically significant impact on appropriateness ratings. CONCLUSION: The physicians surveyed had good knowledge of NNBC prognostic factors, but had a range of opinion on optimal therapy for many clinical scenarios, which reflects current knowledge of the benefits of adjuvant therapy for NNBC.

Adult↗

PubMed1994

Premorbid diet and the prognosis of women with breast cancer.

BACKGROUND: Consumption of a high-fat diet has been associated with poor survival in breast cancer patients. However, studies examining this association are limited and have not used adjustment of energy in their estimates. PURPOSE: The effect of usual diet before diagnosis of breast cancer on the risk of dying of breast cancer was examined in a cohort of women with breast cancer from the National Breast Screening Study (NBSS) in Canada. METHODS: From a cohort of 89,835 women in the NBSS, a total of 1270 histologically confirmed cases of invasive carcinoma of the breast were identified by active follow-up, supplemented by passive follow-up involving record linkage to provincial cancer registries. Of these, 678 case patients who had completed a diet history and were diagnosed from January 1982 up to June 1992 formed the cohort for this investigation. Diet was ascertained from a self-administered diet-history questionnaire. Mortality data were obtained by linkage to the Canadian Mortality Data Base of Statistics Canada, provincial cancer registries, and annual follow-up of cases through physicians. Risk of dying and survival probabilities were estimated by the Cox proportional hazards method and the actuarial life-table method. RESULTS: There were 83 deaths in this study cohort of 678 women; 76 deaths were due to breast cancer, and the remaining seven resulted from other causes. The 5-year survival rate was 90%. For every 5% increase in energy from saturated fat, the risk of dying of breast cancer increased by 50% (hazard ratio = 1.50; 95% confidence interval [CI]: 1.08-2.08). No significant increase in risk was seen with total fat intake (hazard ratio = 1.21; 95% CI = 0.91-1.61) or oleic acid intake (hazard ratio = 1.25; 95% CI = 0.90-1.74). There was a lower risk of dying of breast cancer in the highest quartiles of beta carotene intake (hazard ratio = 0.48; 95% CI = 0.23-0.99) and vitamin C intake (hazard ratio = 0.43; 95% CI: 0.21-0.86); both vitamins showed a significant dose-response relationship (P for trend, < or = .05). These effects varied with menopausal status at diagnosis and tumor characteristics. CONCLUSIONS: These results suggest an increased risk of dying of breast cancer with higher intakes of saturated fat before diagnosis and slightly reduced risk with higher intakes of beta carotene and vitamin C. IMPLICATIONS: More attention should be paid to premorbid dietary habits in relation to breast cancer prognosis. Further studies, however, need to be done with full ascertainment of dietary changes prior to and subsequent to diagnosis.

Adult↗

PubMed1994

Incidence and mortality from breast cancer in the Mama Program for Breast Screening in Finland, 1973-1986.

BACKGROUND: A cohort of women enrolled in the Mama breast self-examination-(BSE) containing breast screening program in Finland from 1973 through 1975 (with BSE used for screening and mammography for diagnosis) was studied. METHODS: Twenty-eight thousand seven hundred eighty-five women who returned calendars recording their practice of BSE over a 2-year period have been followed by linkage with the records of the Finnish Cancer Registry through 1986. The incidence of and mortality from breast cancer was compared with that expected in the Finnish population based on a model incorporating Finnish national data for breast cancer incidence and case fatality. RESULTS: Breast cancer incidence was higher than expected (a rate ratio of 1.19 over all ages). The stage distribution of cases was not different from that expected from Finnish cancer registry data for 1980, but the breast cancer mortality was lower than expected (a rate ratio of 0.75). The latter difference occurred mainly in Years 3-6 of the follow-up period. The effect seemed similar in women under and over the age of 50 years. The cohort was of higher educational status than the Finnish population, and the mortality from all causes was lower than the general Finnish population, an effect seen in previous studies of compliers with breast screening. CONCLUSIONS: The reduction in mortality from breast cancer in the study cohort is consistent with an effect of the BSE-containing Mama program, though selection bias, inherent in any observational study of screening, provided an alternative explanation for the findings.

Adult↗

PubMed1994

Cancer risks associated with occupational exposure to magnetic fields among electric utility workers in Ontario and Quebec, Canada, and France: 1970-1989.

To determine whether occupational exposure to magnetic fields of 50-60 Hz was associated with cancer among electric utility workers, the authors used a case-control design nested within three cohorts of workers at electric utilities: Electricité de France--Gaz de France, 170,000 men; Ontario Hydro, 31,543 men; and Hydro-Québec, 21,749 men. During the observation period, 1970-1989, 4,151 new cases of cancer occurred. Each participant's cumulative exposure to magnetic fields was estimated based on measurements of current exposure of 2,066 workers performing tasks similar to those in the cohorts using personal dosimetry. Estimates were also made of past exposure based on knowledge of current loading, work practices, and usage. Workers who had more than the median cumulative exposure to magnetic fields (3.1 microtesla (microT)-years) had a higher risk for acute nonlymphoid leukemia (odds ratio (OR) = 2.41, 95% confidence interval (CI) 1.07-5.44). The same observation holds for acute myeloid leukemia (OR = 3.15, 95% CI 1.20-8.27). There was also an elevated risk for mean exposure above 0.2 microT (acute nonlymphoid leukemia, OR = 2.36, 95% CI 1.00-5.58; acute myeloid leukemia, OR = 2.25, 95% CI 0.79-6.46). However, there were no clear dose-response trends with increasing exposure and no consistency among the three utilities. Men whose cumulative exposure to magnetic fields was above the 90th percentile (15.7 microT-years) had an elevated risk for brain cancer (OR = 1.95, 95% CI 0.76-5.00) that was not statistically significant. No association with magnetic fields was observed for any of the other 29 types of cancer studied, including skin melanoma, male breast cancer, and prostate cancer. Controlling for potential confounding factors did not change the results.

Aged↗

PubMed1994

Endothelial cell adhesion molecules in psoriasis.

Skin biopsies from patients with psoriasis and normal controls were examined for the expression of cell adhesion molecules including intercellular adhesion molecule-1 (ICAM-1), endothelial leukocyte adhesion molecule-1 (ELAM-1), HECA-452 and 4D10, using an immunoperoxidase techique. This study demonstrates that psoriatic skin exhibits a wide variety of markers of endothelial cell activation which are either induced or increased in expression (ICAM-1, ELAM-1 & 4D10). Moreover, ICAM-1 & HECA-452 are also expressed on leukocytes. These antigens may facilitate the adhesion of inflammatory cells to endothelium and antigen-presenting cells in psoriatic skin. Thus, they may play a role in faciliating the infiltration of leukocytes into psoriatic skin.

Adult↗

PubMed1994

Pulmonary vascular effects of endotoxin in canine lobes pretreated with dapsone.

Endotoxin results in a granulocyte mediated loss of hypoxic pulmonary vasoconstriction (HPV). Dapsone blocks the granulocyte respiratory burst and might, therefore, preserve HPV following endotoxin. Isolated-perfused canine lobes (n = 6) were pretreated with 18 mg/kg dapsone (dapsone group), and compared to six lobes which did not receive dapsone (control group). Total pulmonary vascular resistance (Rtot) and arterial, middle (Rm), and venous segmental resistances were calculated by a vascular occlusion technique. We then administered endotoxin (2 mg/kg) and repeated measurements at 5, 30, and 90 min. The increase in Rm during 3% O2 compared to 35% O2 ventilation was used to define the presence of HPV. In the control group, following endotoxin, values of Rm did not change (P > 0.05) during 3% O2 ventilation (0.011 +/- 0.006 cm H2O/ml/min) compared with 35% O2 ventilation (0.014 +/- 0.005 cm H2O/ml/min). In the dapsone group, following endotoxin, values of Rm increased (P < 0.05) during 3% O2 ventilation (0.06 +/- 0.026 cm H2O/ml/min) compared with 35% O2 ventilation (0.03 +/- 0.015 cm H2O/ml/min). Changes in 6-keto PGF1 alpha or thromboxane B2 do not explain these observations. We conclude that in this experimental preparation, pretreatment with dapsone prevents the loss of HPV associated with endotoxin.

Animals↗

PubMed1993

Mammography.

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Breast Neoplasms↗