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Biomedical subjects

Samuel Y S Wong

Publications and source records attributed to Samuel Y S Wong.

12 recordsLinked to original sources
PubMed2006

Vertebral marrow fat content and diffusion and perfusion indexes in women with varying bone density: MR evaluation.

PURPOSE: To prospectively study the relationship among vertebral marrow fat content, marrow diffusion indexes, and marrow and erector spinae muscle perfusion indexes in female subjects with varying bone mineral density. MATERIALS AND METHODS: Institutional study approval and informed consent were obtained. Dual x-ray absorptiometry, proton magnetic resonance (MR) spectroscopy, diffusion-weighted MR imaging, and dynamic contrast material-enhanced MR imaging of the lumbar spine and erector spinae muscle were performed in 110 women (mean age, 73 years; range, 67-84 years). Marrow fat content, marrow apparent diffusion coefficient (ADC), and perfusion indexes (maximum enhancement and enhancement slope) of marrow and erector spinae muscle were compared among three bone density groups (normal, osteopenic, and osteoporotic). The t test comparisons and Pearson correlations were applied. RESULTS: Seven subjects were excluded, which yielded a final cohort of 103 subjects: 18 with normal bone density, 30 with osteopenia, and 55 with osteoporosis. Vertebral marrow fat content was significantly increased in the osteoporotic group (67.8% +/- 8.5 [standard deviation]) when compared with that of the normal bone density group (59.2% +/- 10.0, P = .002). Vertebral marrow perfusion indexes were significantly decreased in the osteoporotic group (enhancement slope, 1.10%/sec +/- 0.51) compared with those of the osteopenic group (1.45%/sec +/- 0.51, P = .01) and normal bone density group (1.70%/sec +/- 0.52, P < .001). Erector spinae muscle perfusion indexes did not decrease as bone density decreased. The ADC of vertebral marrow did not change with bone density. CONCLUSION: The subjects experienced a decrease in vertebral marrow maximum enhancement and enhancement slope and an increase in marrow fat content as bone density decreased. The reduction in perfusion indexes occurred only within the vertebral body and not in the paravertebral tissues supplied by the same artery.

Absorptiometry, Photon↗
PubMed2006

Lower urinary tract symptoms and depressive symptoms in elderly men.

BACKGROUND: To evaluate the impact of moderate to severe lower urinary tract symptoms (LUTS) on clinically significant depressive symptoms in elderly Chinese men aged 65 and above. METHODS: In a large prospective cohort of 2000 Chinese men aged 65 to 92 years of age in Hong Kong, the association between moderate to severe lower urinary tract symptoms and clinically relevant depressive symptoms was studied. After excluding men with prostate or bladder cancer or surgery, 1980 subjects provided response to a structured interviewer-administered questionnaire and physical examination. A case-control analysis was performed, comparing subjects with clinically relevant depressive symptoms (cases) to those without depressive symptoms (controls). RESULTS: In multiple analyses adjusting for all factors that were shown to be significantly associated with having clinically relevant depressive symptoms in the initial bivariate analyses, being widowed, divorced or single were associated with increased risk of having clinically relevant depressive symptoms. Having a history of cardiac disease, being a current smoker and the use of corticosteroid were also associated with increased risk. Having moderate to severe LUTS was significantly associated with increased odds of having clinically relevant depressive symptoms (OR: 2.40; CI: 1.68-3.43) even after adjustment. LIMITATION: This study was cross-sectional and there were no clinician-based diagnostic interviews that were conducted to diagnose clinical depression and thus only clinically relevant depressive symptoms were assessed. CONCLUSIONS: In elderly men, moderate to severe LUTS are important public health problems that are associated with increased risk of having clinically relevant depressive symptoms. These findings suggest that physicians who deal with patients with moderate to severe LUTS should consider the psychological health of their patients as this population is at risk of having clinically relevant depressive symptoms.

Adrenal Cortex Hormones↗
PubMed2006

Risk of depression in patients with chronic respiratory diseases: results from two large cohort studies in Chinese elderly from Hong Kong.

OBJECTIVE: Although it has been suggested that depression is common in patients with chronic respiratory diseases such as chronic obstructive pulmonary disease (COPD), few studies on the association between chronic respiratory diseases and depression have been conducted in the community. METHOD: Data from the baseline examination of two cohort studies, Mr and Ms Os, Hong Kong were used. Three thousand nine hundred and ninety-eight Hong Kong men and women aged 65 to 92 were recruited. Depression was assessed by face-to-face interview, using the short-form of a validated Chinese version of the Geriatric Depression Scale (GDS). Chronic respiratory disease was assessed by subjects' self reports of chronic respiratory disease (chronic bronchitis, emphysema and asthma) diagnosed by medical doctors. Adjusted odds ratios (ORs) and corresponding 95% confidence intervals (CI) for depression among subjects with chronic respiratory diseases relative to those without (controls) were calculated, after adjustments were made for potential confounders. RESULTS: Chronic respiratory disease was associated with a higher prevalence of depressive disorders with an odds ratio of 1.58 (95% CI = 1.12-2.13) after adjustment was made for age, sex, cigarette smoking, alcohol drinking and history of cardiovascular diseases when compared with controls. For those subjects with self report of chronic respiratory disease and who screened positive for depression (n = 44), none were on antidepressants. Among subjects who screened positive for depression without self-report of chronic respiratory disease (n = 328), only 2.74% (n = 9) were on antidepressants. CONCLUSIONS: We conclude that chronic respiratory disease is independently associated with depression in Chinese elderly. Moreover, depression in the elderly is under-treated in those with and without chronic respiratory disease. Clinicians, especially primary care physicians in the community, should be more aware of increased prevalence of depression in patients with chronic respiratory disease.

Aged↗
PubMed2006

Strengths, weaknesses, and development of Traditional Chinese Medicine in the health system of Hong Kong: through the eyes of future Western doctors.

Five focus group discussions were conducted with 28 (fourth-year) medical students from the Chinese University of Hong Kong (CUHK) to explore attitudes to Traditional Chinese Medicine (TCM) and its impact on the future of medical training. Most students perceived that TCM was a good alternative for certain health problems but lack of scientific evidence and the absence of regulation were major barriers. Students were concerned about the limitations of TCM, but identified their need to understand TCM to effectively communicate with their patients. Paralleled with the experience in the United Kingdom and other countries, if traditional and conventional doctors are to work effectively side by side, current medical education and health service arrangements need to change.

Adult↗
PubMed2005

Vertebral bone mineral density, marrow perfusion, and fat content in healthy men and men with osteoporosis: dynamic contrast-enhanced MR imaging and MR spectroscopy.

PURPOSE: To prospectively use hydrogen 1 (1H) magnetic resonance (MR) spectroscopy and dynamic contrast material-enhanced MR imaging to measure vertebral body marrow fat content and bone marrow perfusion in older men with varying bone mineral densities as documented with dual x-ray absorptiometry (DXA). MATERIALS AND METHODS: This study had institutional review board approval, and all participants provided informed consent. DXA, 1H MR spectroscopy, and dynamic contrast-enhanced MR imaging of the lumbar spine were performed in 90 men (mean age, 73 years; range, 67-101 years). Vertebral marrow fat content and perfusion (maximum enhancement and enhancement slope) were compared for subject groups with differing bone densities (normal, osteopenic, and osteoporotic). The t test was used for comparisons between groups, and the Pearson test was used to determine correlation between marrow fat content and perfusion indexes. RESULTS: Eight subjects were excluded, yielding a final cohort of 82 subjects (mean age, 73 years; range, 67-101 years) that included 42 subjects with normal bone density (mean T score, 0.8 +/- 1.1 [standard deviation]), 23 subjects with osteopenia (mean T score, -1.6 +/- 0.4), and 17 subjects with osteoporosis (mean T score, -3.2 +/- 0.5). Vertebral marrow fat content was significantly increased in subjects with osteoporosis (mean fat content, 58.23% +/- 7.8) (P = .002) or osteopenia (mean fat content, 55.68% +/- 10.2) (P = .034) compared with that in subjects with normal bone density (50.45% +/- 8.7). Vertebral marrow perfusion indexes were significantly decreased in osteoporotic subjects (mean enhancement slope, 0.78%/sec +/- 0.3) compared with those in osteopenic subjects (mean enhancement slope, 1.15%/sec +/- 0.6) (P = .007) and those in subjects with normal bone density (mean enhancement slope, 1.48%/sec +/- 0.7) (P < .001). CONCLUSION: Subjects with osteoporosis have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with osteopenia. Similarly, subjects with osteopenia have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with normal bone density.

Absorptiometry, Photon↗
PubMed2005

Procedures in primary care dermatology.

BACKGROUND: General practitioners can provide a range of diagnostic and treatment procedures for patients with dermatological problems. OBJECTIVE: This article reviews the use of Wood's light, diascopy, skin scrapings for microscopy, skin biopsy, cauterisation, doppler measurement of ankle-brachial pressure index, and multi-layer compression bandages for venous ulcers. DISCUSSION: Adequate training and proper equipment is essential for commonly neglected areas including informed written consent, good communication with the histopathologist, a system for handling specimens and reports, action plans for laboratory results, and adequate training and protection for auxiliary staff.

Bandages↗
PubMed2004

Depression and bone mineral density: is there a relationship in elderly Asian men? Results from Mr. Os (Hong Kong).

Previous epidemiological study has suggested that depression might be associated with low bone mass in Caucasian women. This has not been studied in Asian men. Mr. Os (Hong Kong) is the first, large, cohort study on osteoporosis in Asian men, and the current analysis deals with the association between depression and bone mass in this group. Data from the baseline examination of Mr. Os (Hong Kong) were used. Two thousand Hong Kong men aged 65 to 92 years were recruited from the community. Depression was diagnosed by face-to-face interview, using a validated Chinese version of the Geriatric Depression Scale (GDS), with depression being defined as a cut-off score of 8 or more. Bone mineral density (BMD) of the lumbar spine, total hip and total body was measured by dual X-ray densitometry (DEXA) using the Hologic QDR-4500 W densitometer. Multiple regression was used to compare BMD in depressed and non-depressed subjects, controlling for confounding variables. In the study sample 8.5% of men were found to be depressed, and the BMD at the total hip in these subjects was 2.1% lower than in non-depressed subjects (95% CI -0.13 to -4.1), after adjustment for age, body weight, medical history, alcohol consumption, cigarette smoking, calcium intake, physical activity and antidepressant use. Depression was associated with a 1.4-fold (95% CI 1.00 to 2.08) relative risk (RR) of being diagnosed with a T-score equal to or less than -1.0 (low bone mass). We conclude that depression is associated with lower BMD; however, to determine whether depression causes lower BMD or vice versa, we will need to await findings from future prospective studies.

Absorptiometry, Photon↗
PubMed2004

Bone marrow diffusion in osteoporosis: evaluation with quantitative MR diffusion imaging.

PURPOSE: To determine the diffusion of vertebral body marrow with quantitative MR diffusion imaging and to examine whether differences exist between subjects with postmenopausal osteoporosis and premenopausal control subjects. MATERIALS AND METHODS: A total of 44 consecutive women (mean age, 70 years) with documented bone mineral density (BMD) measured by dual energy x-ray absorptiometry (T-score) and 20 normal subjects (mean age, 28 years) were examined with echo-planar diffusion imaging at 1.5 T using b values of 0, 20, 40, 60, 80, 100, 200, 300, 400, and 500 seconds/mm2. Extravascular diffusion (D) and apparent diffusion coefficient (ADC) were calculated and results from both groups compared. RESULTS: Both D and ADC values tended to decrease with decreasing BMD. Mean D values were significantly lower in postmenopausal women with reduced BMD (0.42 +/- 0.12 x 10(-3) mm2/second) than normal premenopausal women (0.50 +/- 0.09 x 10(-3) mm2/second). Mean ADC values were significantly lower both in subjects with reduced BMD (0.41 +/- 0.10 x 10(-3) mm2/second) and normal BMD (0.43 +/- 0.08 x 10(-3) mm2/second) compared to normal controls (0.49 +/- 0.07 x 10(-3) mm2/second). CONCLUSION: Accumulation of fatty bone marrow associated with osteoporosis is reflected by a decrease in D and ADC. Diffusion imaging may prove useful in the study of osteoporosis.

Adult↗