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Biomedical subjects

Angela M Cheung

Publications and source records attributed to Angela M Cheung.

At least 19 recordsLinked to original sources
PubMed2006

The effects of atamestane and toremifene alone and in combination compared with letrozole on bone, serum lipids and the uterus in an ovariectomized rat model.

We compared the effects of atamestane (ATA) and toremifene (TOR) alone and in combination, with letrozole (LET) on bone, serum lipids and the uterus in ovariectomized (OVX) rats after 16 weeks of treatment. Compared to OVX controls lumbar vertebral and femoral BMD as well as mechanical strength and trabecular bone volume were significantly greater in animals given ATA, TOR or ATA + TOR. The effects of ATA were not reversed by the androgen receptor blocker, flutamide (FLT). Serum cholesterol, low-density lipoprotein cholesterol and triglycerides were reduced by TOR and ATA + TOR whereas they remained unchanged in animals receiving ATA, ATA + FLT, and LET. The uterine epithelium in OVX animals was equally stimulated by TOR and ATA + TOR and unaffected by ATA or LET. Intact animals had significant atrophy of the uterine epithelium when receiving ATA. In summary, TOR alone or in combination with ATA had a predictable stimulatory effect on bone and the uterine epithelium while reducing key parameters of lipid metabolism. In contrast, ATA but not LET had an unexpected stimulatory effect on the OVX rat's bone and this was not reversed by the anti-androgen FLT leaving this finding unexplained for now. ATA is distinct from LET on end-organ function and this favorable profile makes clinical testing of this steroidal aromatase inhibitor of interest in the clinical setting.

Androstenedione↗
PubMed2006

Two-year outcomes, health care use, and costs of survivors of acute respiratory distress syndrome.

RATIONALE: Little is known about the long-term outcomes and costs of survivors of acute respiratory distress syndrome (ARDS). OBJECTIVES: To describe functional and quality of life outcomes, health care use, and costs of survivors of ARDS 2 yr after intensive care unit (ICU) discharge. METHODS: We recruited a cohort of ARDS survivors from four academic tertiary care ICUs in Toronto, Canada, and prospectively monitored them from ICU admission to 2 yr after ICU discharge. MEASUREMENTS: Clinical and functional outcomes, health care use, and direct medical costs. RESULTS: Eighty-five percent of patients with ARDS discharged from the ICU survived to 2 yr; overall 2-yr mortality was 49%. At 2 yr, survivors continued to have exercise limitation although 65% had returned to work. There was no statistically significant improvement in health-related quality of life as measured by Short-Form General Health Survey between 1 and 2 yr, although there was a trend toward better physical role at 2 yr (p = 0.0586). Apart from emotional role and mental health, all other domains remained below that of the normal population. From ICU admission to 2 yr after ICU discharge, the largest portion of health care costs for a survivor of ARDS was the initial hospital stay, with ICU costs accounting for 76% of these costs. After the initial hospital stay, health care costs were related to hospital readmissions and inpatient rehabilitation. CONCLUSIONS: Survivors of ARDS continued to have functional impairment and compromised health-related quality of life 2 yr after discharge from the ICU. Health care use and costs after the initial hospitalization were driven by hospital readmissions and inpatient rehabilitation.

Adult↗
PubMed2006

Osteoporosis in primary biliary cirrhosis: a randomized trial of the efficacy and feasibility of estrogen/progestin.

The optimal therapy for the prevention and treatment of osteoporosis in primary biliary cirrhosis (PBC) is unknown. Hormone replacement therapy (HRT) prevents osteoporosis, but may promote cholestasis. We performed a double-blind, randomized, placebo-controlled trial of transdermal estrogen/progestin in postmenopausal women with PBC. The 24-month study enrolled 31 patients, but trial uptake was limited and treatment arm dropout was significant. Placebo-treated patients had a higher percentage loss in femoral neck bone mineral density than actively treated patients (-3.76 +/- 1.37% versus 0.21 +/- 1.01%, respectively, P = .058). New fractures occurred in 2 patients on placebo, and in no patients on treatment. The mean monthly increase in bilirubin was not significantly different between groups, but individual data suggest HRT may worsen cholestasis. In conclusion, women with PBC have strong feelings about HRT, and recruitment for this intervention is difficult. Transdermal estrogen/progestin likely provides protection against bone loss in PBC patients, but may worsen cholestasis.

Administration, Cutaneous↗
PubMed2006

Stroke survivors' behavioral and psychologic symptoms are associated with informal caregivers' experiences of depression.

OBJECTIVE: To determine the impact of stroke survivors' behavioral and psychologic symptoms (BPS) on informal caregivers' experience of depression in the context of the caregiving situation. DESIGN: Cross-sectional survey using a structured quantitative interview. SETTING: Rehabilitation facility outpatient clinic, tertiary care facility outpatient clinic, and community care organizations. PARTICIPANTS: Ninety-four informal caregivers to stroke survivors completed standardized measurement instruments. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Measurement instruments included the Center for Epidemiological Studies Depression Scale, Brain Impairment Behavior Inventory-Revised, Caregiver Assistance Scale, Caregiving Impact Scale, and Mastery scale. RESULTS: A substantial percentage (44.7%) of caregivers were at risk of clinical depression. Caregivers experienced more depression symptoms when they cared for stroke survivors exhibiting more BPS of memory and comprehension difficulties, provided less assistance, experienced more lifestyle interference, and had lower mastery (F(5,85)=26.02, P<.001, adjusted R(2)=.58). CONCLUSIONS: BPS exhibited by stroke survivors contribute to informal caregivers' experience of depression. These results can assist rehabilitation professionals to identify informal care providers who are at greater risk of experiencing emotional distress and, therefore, may benefit from intervention.

Activities of Daily Living↗
PubMed2006

Prevention and management of osteoporosis in men receiving androgen deprivation therapy: a survey of urologists and radiation oncologists.

OBJECTIVES: To determine the current practice of clinicians in the diagnosis and management of osteoporosis among men taking androgen deprivation therapy (ADT), because ADT leads to decreased bone mineral density (BMD) and fractures. METHODS: We sent out a survey to Canadian urologists and radiation oncologists. The survey included questions about BMD testing, treatment practices, referral patterns, and risk of osteoporosis. RESULTS: The surveys were returned by 170 of 294 respondents (response rate 58%). Few respondents would obtain a baseline BMD in patients starting ADT. Forty percent would order a repeat BMD test after starting ADT if the baseline BMD were normal or unknown, but more than two thirds would if the baseline BMD showed osteoporosis. In men with a normal BMD starting ADT, respondents recommended weight-bearing exercises (58%), calcium (50%), vitamin D (47%), and bisphosphonate (6%) supplements. In men with osteoporosis at baseline, the use of nonprescription therapies increased slightly and bisphosphonate use increased to 44%. If osteoporosis were diagnosed, 11% would treat the patient themselves. The estimated risk of developing osteoporosis within 1 year of starting ADT with a normal baseline BMD ranged from 0% to 90% (median 20%). CONCLUSIONS: To our knowledge, this is the first survey of its kind. The key findings included that few physicians would order a baseline BMD test, would prescribe bisphosphonates for prevention but almost one half would consider bisphosphonates to treat established osteoporosis, and wide variations exist in the practice patterns and risk perception surrounding ADT-related osteoporosis. Evidence-based guidelines are needed to help physicians deal effectively with osteoporosis prevention and management among men taking ADT.

Androgen Antagonists↗
PubMed2006

Well-being in informal caregivers of survivors of acute respiratory distress syndrome.

OBJECTIVE: With limited community services, the complex rehabilitation period after critical illness is often the responsibility of family members who, as a result, may experience negative health outcomes. The objectives of this research were to a) identify aspects of the caregiving situation that are associated with caregivers' experiences of emotional distress and psychological well-being; and b) compare health-related quality of life of informal caregivers to survivors of acute respiratory distress syndrome (ARDS) with age- and gender-matched population values. DESIGN: Cross-sectional survey of informal caregivers to ARDS survivors. SETTING: Toronto, Ontario, Canada. PATIENTS: Informal caregivers were individuals who were primarily responsible for providing and/or coordinating ARDS survivors' posthospital care and were not paid to do so. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The dependent variables were emotional distress, psychological well-being, and health-related quality of life. They were evaluated by the Center for Epidemiologic Studies Depression Scale, the Positive Affect Scale, and Medical Outcomes Study Short Form 36, respectively. Independent variables included severity of illness indicators, patient depression (Beck Depression Inventory II), aspects of the caregiving experience (care provided, lifestyle interference, personal gain), and psychosocial resources (mastery and social support). Caregivers experienced more emotional distress when they experienced more lifestyle interference, had lower levels of mastery, and were caring for ARDS survivors with more depressive symptoms (F3,42 = 15.69, p < .001, adjusted R = .50). In contrast, caregiver psychological well-being was associated with personal gains as a result of providing care and having more mastery and social support (F4,41 = 9.40, p < .001, adjusted R = .43). Caregivers reported poorer health-related quality of life across all domains of the Medical Outcomes Study Short Form 36 compared with age- and gender-matched population values. CONCLUSIONS: Informal caregivers experience negative health outcomes that persist almost 2 yrs after ARDS. New approaches, such as family-centered rehabilitation, caregiver education, improved respite, and home care, may benefit informal caregivers.

Adult↗
PubMed2005

Sex differences in stroke care and outcomes: results from the Registry of the Canadian Stroke Network.

BACKGROUND: Stroke is an important cause of death and disability in women as well as men. However, little is known about sex differences in stroke care and outcomes. METHODS: The Registry of the Canadian Stroke Network (RCSN) captured data on patients with stroke seen at acute care hospitals across Canada. We used data from phase 1 (July 2001 to February 2002) and phase 2 (June to December 2002) of the RCSN to compare stroke presentation, management, and 6-month outcomes in women and men using multivariable regression techniques to adjust for age and other factors. RESULTS: The study sample included 3323 patients, with 1527 women. Stroke symptoms at presentation were similar in women and men, except that women were more likely to present with headaches and were less likely to have brain stem or cerebellar symptoms. There were no sex differences in the use of neuroimaging, thrombolysis, antithrombotic therapy, or consultations. Women were less likely than men to receive care on an acute stroke unit, but this difference was no longer significant after adjustment for age and other factors. Women were more likely than men to be discharged to long-term care and had greater disability at 6 months. Mortality and quality of life at 6 months were similar in women and men. CONCLUSIONS: Among patients participating in the RCSN, there were no major sex differences in stroke presentation or management. Compared with men, women were more often institutionalized and had a slightly worse functional status at 6 months after stroke.

Disability Evaluation↗
PubMed2005

Raloxifene and colorectal cancer.

OBJECTIVE: To determine the effect of raloxifene on colorectal cancer (CRC) risk. METHODS: We analyzed data from the Multiple Outcomes of Raloxifene Evaluation (MORE) trial, a randomized, blinded clinical trial designed to determine the effect of raloxifene on vertebral fracture risk. In this trial, 7705 women received either raloxifene or placebo and were followed for an average of 3.4 years. CRC cases were classified as definite (pathology available), probable (imaging or colonoscopic diagnosis), or possible (self-report). Relative hazard for CRC was calculated using multivariate Cox proportional hazards models. RESULTS: Fifty cases of definite or probable CRC were diagnosed; 40 were definite and 10 probable. Twenty-nine cases occurred among the 5129 women in the raloxifene group, and 21 occurred among the 2576 women in the placebo group (p = 0.15). The relative hazard for CRC for women treated with raloxifene was 0.78 (95% CI 0.43, 1.43, p = 0.43). Restricting the analysis to definite CRC, the relative hazard was 0.77 (95% CI 0.39, 1.5, p = 0.45). CONCLUSIONS: Although the MORE trial was large, the number of CRC cases was too small to provide definitive evidence concerning the effect of raloxifene on CRC risk. There does not appear to be a substantial increased risk of CRC with raloxifene use. Studies including larger numbers of women and women at risk for CRC should further investigate the effect of raloxifene on CRC.

Aged↗
PubMed2005

A community-based intervention to increase screening mammography among disadvantaged women at an inner-city drop-in center.

PURPOSE: To determine the effectiveness of a community- based intervention to increase the use of screening mammography among disadvantaged women at an inner-city drop-in center. METHODS: This study involved women 50 to 70 years old who were clients of an inner-city drop-in center in Toronto, Canada, during the years 1995-2002 (N = 158 in 1995-2001 and N = 89 in 2002). In 2002, the drop-in center and a nearby hospital initiated a collaborative breast cancer screening project in which a staff member of the drop-in center accompanied small groups of women for mammography visits at a weekly pre-arranged time. Interrupted time series analysis was used to examine the effect of this intervention on the annual rate of screening mammography, as determined by review of medical records. RESULTS: More than half of the women 50 to 70 years old who used the drop-in center in 2002 had been diagnosed with a major mental illness, and one-third were either homeless or living in supportive housing. In the 7 years before the introduction of the intervention, annual mammography rates among women using the drop-in center averaged 4.7%. During the intervention year, 26 (29.2%) of 89 women underwent mammography (p = 0.0001 for the change from pre-to post-intervention). CONCLUSIONS: The introduction of accompanied small-group visits was associated with significantly increased use of mammography in a group of disadvantaged women who were clients of an inner-city drop-in center. This approach may be useful to promote breast cancer screening among women affected by mental illness or homelessness who have contact with community-based agencies.

Aged↗
PubMed2005

Reproducibility of DXA estimations of body fat in HIV lipodystrophy: implications for clinical research.

Dual-energy X-ray absorptiometry (DXA) estimates of body fat are increasingly used for the evaluation of human immunodeficiency virus lipodystrophy (HIV LD); however, limited data are available on their reproducibility. This information is essential for using this tool as an end point in treatment trials or as a diagnostic tool. This study evaluates the reproducibility of DXA body fat estimation in HIV-positive subjects with and without lipodystrophy. Thirty subjects representing a spectrum of severity of fat redistribution underwent same-day repeat whole-body DXA scans (Hologic QDR 4500A scanner). Root mean square coefficients of variation (RMS-CV) were used to estimate minimum detectable differences (MDDs) for body fat content in different regions. Absolute MDD was calculated by multiplying the MDD by the mean fat-mass value for each anatomical area. The RMS-CV ranged from 4.0% for arm fat to 1.6% for total fat. Relative and absolute MDD values ranged from 11.0% or 160 g for arm fat to 4.3% or 628 g for total fat. DXA measurements of regional body fat mass in subjects with HIV show similar reproducibility to other populations. Minimal detectable differences were smaller than differences observed in published studies for all measurements. DXA is a sensitive tool for detecting changes in peripheral fat among patients with HIV lipodystrophy.

Absorptiometry, Photon↗
PubMed2004

Effects of the steroidal aromatase inhibitor exemestane and the nonsteroidal aromatase inhibitor letrozole on bone and lipid metabolism in ovariectomized rats.

PURPOSE: Exemestane (EXE) and letrozole (LET) are third-generation aromatase inhibitors currently prescribed for postmenopausal hormone-dependent breast cancer. The impact on end organs of estrogen depletion in menopausal women is of significant clinical importance. We studied the effects of EXE, its principal metabolite, 17-hydroexemestane (17-H-EXE), and LET on bone and lipid metabolism in ovariectomized (OVX) rats. EXPERIMENTAL DESIGN: OVX rats were treated by weekly intramuscular injection for 16 weeks with 20, 50, and 100 mg/kg EXE, 20 mg/kg 17-H-EXE, and daily oral gavage of 1 mg/kg LET. At the end of the treatment period, bone mineral density (BMD), the bone resorption marker serum pyridinoline, the bone formation marker serum osteocalcin, bone mechanical properties, histomorphometry, and serum lipid concentrations were determined. RESULTS: Lumbar vertebral and femoral BMD, bending strength of the femur, compressive strength of the fifth lumbar vertebra, and trabecular bone volume were significantly higher in OVX animals given EXE and 17-H-EXE than in OVX controls. EXE and 17-H-EXE significantly reduced an ovariectomy-induced increase in serum pyridinoline and serum osteocalcin. EXE and 17-H-EXE given to OVX rats caused significant reductions of serum cholesterol and low-density lipoprotein cholesterol. In contrast, OVX rats treated with LET had BMD, bone biomarkers, mechanical failure properties, and lipid levels similar to those of OVX controls. CONCLUSIONS: EXE and 17-H-EXE significantly prevent bone loss, enhance bone mechanical strength, and lower serum cholesterol and low-density lipoprotein levels in OVX rats. These protective effects on end-organ function are not seen with the nonsteroidal inhibitor LET.

Amino Acids↗
PubMed2004

Perimenopausal and Postmenopausal Health.

HEALTH ISSUE: The average age of natural menopause in Western societies is estimated to be 51 years; women in Canada can therefore expect to live, on average, a third of their lives in post-menopausal years. During these years women are at increased risk of chronic diseases such as osteoporosis and cardiovascular disease. KEY FINDINGS: Clinical and epidemiological data on women in perimenopause are limited. There are no adequate Canadian data on symptom severity and prevalence among perimenopausal and postmenopausal women. Scientific evidence is lacking to support or refute claims that commonly used botanical products can offer therapeutic relief of menopausal symptoms.Recent data from the Women's Health Initiative suggest that combined estrogen plus therapy increases the risk of stroke, coronary artery disease and breast cancer. Hormone therapy is no longer recommended for the prevention of chronic diseases for asymptomatic women. Stroke is an important issue for perimenopausal and postmenopausal women and sex differences may exist in the progestin treatment of stroke. Osteoporosis affects an estimated one in six women over the age of 50. DATA GAPS AND RECOMMENDATIONS: There is a need to conduct clinical and epidemiological research aimed at better understanding the menopausal transition and defining its clinical phases. Investigations aimed at alternative combinations and doses of hormone therapy and non-pharmaceutical alternatives in light of known risks and benefits are also necessary. Health care practitioners and women need to be educated on the risks and effective treatment related to cardiovascular disease so they can present for treatment more quickly and receive the most effective therapies.

Journal Article↗
PubMed2004

Risk of death among homeless women: a cohort study and review of the literature.

BACKGROUND: Homeless people are at high risk for illness and have higher death rates than the general population. Patterns of mortality among homeless men have been investigated, but less attention has been given to mortality rates among homeless women. We report mortality rates and causes of death in a cohort of women who used homeless shelters in Toronto. We also compare our results with those of other published studies of homeless women and with data for women in the general population. METHODS: A cohort of 1981 women not accompanied by dependent children who used homeless shelters in Toronto in 1995 was observed for death over a mean of 2.6 years. In addition, we analyzed data from published studies of mortality rates among homeless women in 6 other cities (Montreal, Copenhagen, Boston, New York, Philadelphia and Brighton, UK). RESULTS: In Toronto, mortality rates were 515 per 100,000 person-years among homeless women 18-44 years of age and 438 per 100,000 person-years among those 45-64 years of age. Homeless women 18-44 years of age were 10 times more likely to die than women in the general population of Toronto. In studies from a total of 7 cities, the risk of death among homeless women was greater than that among women in the general population by a factor of 4.6 to 31.2 in the younger age group and 1.0 to 2.0 in the older age group. In 6 of the 7 cities, the mortality rates among younger homeless women and younger homeless men were not significantly different. In contrast, in 4 of the 6 cities, the mortality rates were significantly lower among older homeless women than among older homeless men. INTERPRETATION: Excess mortality is far greater among homeless women under age 45 years than among older homeless women. Mortality rates among younger homeless women often approach or equal those of younger homeless men. Efforts to reduce deaths of homeless women should focus on those under age 45.

Adolescent↗
PubMed2004

The selective estrogen receptor modulator SCH 57068 prevents bone loss, reduces serum cholesterol and blocks estrogen-induced uterine hypertrophy in ovariectomized rats.

Our objective was to determine the effects of SCH 57068 alone and with 17 beta-estradiol (E(2)) on bone, lipids and uteri in ovariectomized (OVX) rats. In OVX animals lumbar vertebral and femoral bone mineral density (BMD) were significantly higher after 12 weeks of treatment with SCH 57068 than in untreated OVX controls. Similarly BMD was superior in OVX + E(2) + SCH 57068 treated animals than in OVX + E(2) controls. SCH 57068 also significantly reduced the increase in bone turnover markers, serum pyridinoline and serum osteocalcin levels, induced by OVX, and increased mechanical bone strength. SCH 57068 also significantly reduced the rise in serum cholesterol and low-density lipoprotein cholesterol induced by OVX. SCH 57068 had no stimulatory effect on uterine epithelium when given alone in OVX rats. SCH 57068 (1 and 2.5 mg/kg) reduced uterine weight and blocked endometrial stimulation induced by E(2). In summary, SCH 57068 adds to the positive effects of E(2) on bone and lipid metabolism but blocks the stimulatory effects of E(2) on the uterus. Potentially, E(2) + SCH 57068 could be combined for the treatment and prevention of breast cancer or as a novel hormone replacement therapy.

Animals↗