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Biomedical subjects

J Woo

Publications and source records attributed to J Woo.

At least 19 recordsLinked to original sources
PubMed2007

Differential modulation of myosin heavy chain phenotype in an inactive extensor and flexor muscle of adult rats.

The effects of chronic neuromuscular inactivity on the phenotype and size of muscle fibres in a fast ankle extensor (medial gastrocnemius, MG) and a fast ankle flexor (tibialis anterior, TA) muscle of the rat hindlimb were determined. Inactivity was produced by spinal cord isolation (SI), i.e. complete spinal cord transections at a mid-thoracic and high sacral level and bilateral deafferentation between the transection sites. After 90 days of SI, the MG and TA muscle weights were 53 and 45% lower than in age-matched controls. Overall mean fibre sizes in the deep (close to the bone) and superficial (away from the bone) regions were approximately 60 and 65% smaller in the MG and approximately 40 and 50% smaller in the TA of SI than control rats, respectively. The myosin heavy chain (MHC) composition shifted towards the faster isoforms after SI: the MG showed an increase in both types IIx (20%) and IIb (23%), whereas the TA showed a marked increase in type IIx (94%) and a decrease in type IIb (18%) MHC. Both muscles in SI rats showed no type IIa and only one MG muscle had approximately 5% type I MHC. These results show that prolonged inactivity has a stronger effect on a fast extensor compared with a fast flexor in the rat hindlimb. The larger decrease in mass and fibre size in the MG than the TA most probably reflects the larger impact of chronic inactivity on the normally more highly recruited extensor than flexor muscle. The primary shift to type IIb MHC in the MG and type IIx MHC in the TA indicate a different default mode for an inactive extensor vs. flexor muscle, and may reflect differing activity-independent neural influences, i.e. neurotrophic factors, on muscle fibre phenotype in extensors vs. flexors.

Animals↗
PubMed2006

Acupuncture for stroke rehabilitation.

BACKGROUND: Stroke is the third leading cause of death in Western society; in China it is the second most common cause of death in cities and the third in rural areas. It is also a main cause of adult disability and dependency. Acupuncture for stroke has been used in China for hundreds of years and is increasingly practiced in some Western countries. OBJECTIVES: To assess the efficacy and safety of acupuncture for patients with stroke in the subacute or chronic stage. SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (November 2005), the Cochrane Complementary Medicine Field Trials Register (November 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2005), MEDLINE (1966 to November 2005), EMBASE (1980 to November 2005), CINAHL (1982 to November 2005), AMED (1985 to November 2005), the Chinese Stroke Trials Register (November 2005), the Chinese Acupuncture Trials Register (November 2005), the Chinese Biological Medicine Database (1977 to November 2005), the National Center for Complementary and Alternative Medicine Register (November 2005), and the National Institute of Health Clinical Trials Database (November 2005). We handsearched four Chinese journals and checked reference lists of all papers identified for further trials. SELECTION CRITERIA: Truly randomised unconfounded clinical trials among patients with ischemic or hemorrhagic stroke, in the subacute or chronic stage, which compared acupuncture involving needling with either placebo acupuncture, sham acupuncture or no acupuncture. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials for inclusion, assessed quality, extracted and cross-checked the data. MAIN RESULTS: Five trials (368 patients) met the inclusion criteria. Methodological quality was considered inadequate in all trials. Although the overall estimate from four trials suggested the odds of improvement in global neurological deficit was higher in the acupuncture group compared with the control group (odds ratio (OR) 6.55, 95% confidence interval (CI) 1.89 to 22.76), this estimate may not be reliable since there was substantial heterogeneity (I(2 )= 68%). One trial showed no significant improvement of motor function between the real acupuncture group and the sham acupuncture group (OR 9.00, 95% CI 0.40 to 203.30), but the confidence interval was wide and included clinically significant effects in both directions. No data on death, dependency, institutional care, change of neurological deficit score, quality of life or adverse events were available. AUTHORS' CONCLUSIONS: Currently there is no clear evidence on the effects of acupuncture on subacute or chronic stroke. Large, methodologically-sound trials are required.

Acupuncture Therapy↗
PubMed2006

Public health significance of the frailty index.

BACKGROUND: A quantifiable indicator of frailty would be very useful in assessing the health state of older populations, as well as enable the effect of interventions to be evaluated over time. METHODS: A total of 2032 people aged 70 years and over recruited by stratified random sampling, and information obtained regarding physical and functional health, and psychological factors. The frailty index (FI) was constructed from 62 variables. Associations between the FI, and changes in ADL score, mental score, and hospitalization days over a 10-year period were evaluated. RESULTS: For the baseline to 3-year changes, a 0.10 increase in baseline FI is accompanied by a 0.499-point faster drop in ADL score, a 0.223-point faster decline in mental score, and 4.57-day faster increase in hospital days. For 3-10-year changes, frailty was a significant predictor only of changes in mental score, with results indicating that, on average, each increase of 0.10 in the baseline frailty index was associated with 0.613-point drop in mental score during this period. Chronological age and frailty had differential associations with those changes. CONCLUSION: The FI is a valid indicator of morbidity and requirement for health and social services for ageing populations.

Activities of Daily Living↗
PubMed2006

Nutrient intake and psychological health in an elderly Chinese population.

BACKGROUND: Associations between nutrition and cognitive impairment, and nutrition and depression, have been observed. Elderly people are at risk of under nutrition, and also have higher prevalence of cognitive impairment and depression. OBJECTIVE: To examine the relationship between nutrient intake and psychological health in the elderly, adjusting for confounding factors. SUBJECTS: Three thousand nine hundred and ninety-nine men and women aged 65 years and over living in the community, with approximately equal numbers in three age groups: 65-69, 70-74, 75+ years. METHODS: Dietary intake was assessed using a 7-day food frequency questionnaire. Cognitive function was assessed by the cognitive part of the Community Screening Instrument for Dementia (CSID). Depression was assessed using the Geriatric Depression Scale (GDS). Information was also collected for confounding factors: demographics, educational level, socioeconomic status, medical history, smoking, alcohol intake, and physical activity. Logistic regression analyses were carried out to examine associations between lifestyle and dietary variables, and CSID and GDS, controlling for confounders. RESULTS: Both CSID and GDS scores were associated with co-morbidity, demographic and socioeconomic factors. Few associations between lifestyle factors and CSID score were observed. Dietary factors inversely associated with GDS score include total fat intake, vitamins A, B2, B3, C, fibre, and vegetables. In terms of nutrient density, iron and isoflavone intake were additional factors. CONCLUSION: Association exists between intake of various nutrients and psychological health independent of other confounding factors in the elderly population. A follow-up study of this cohort or interventional studies are needed to elucidate cause effect relationship.

Aged↗
PubMed2006

Evaluation of the effect of energy conservation techniques in the performance of activity of daily living tasks.

OBJECTIVE: To determine whether energy conservation techniques during common activity of daily living tasks actually result in lower energy expenditure, and to document subjective comments regarding any differences in the perceived level of effort. DESIGN: Descriptive study comparing energy expenditure in three tasks with and without energy conservation techniques, taking into account the effect of age. SETTING: Occupational therapy department of a rehabilitation hospital in Hong Kong. SUBJECTS: One hundred and eight subjects (30 < 60 years; 78 > or = 60 years) were recruited from staff and members of an elderly social centre in the community. MEASUREMENTS: Energy expenditure was measured using a portable indirect calorimetry system for three tasks (shopping, washing clothes and hanging laundry) with and without energy conservation techniques. Dyspnoea, fatigue and perceived exertion were measured using visual analogue scales. RESULTS: Reduction in energy expenditure using energy conservation techniques for shopping and hanging laundry was documented in younger subjects only (O2 consumption fell from 13.8 +/- 3.7 to 12.2 +/- 3.8 mL/min per kg for shopping, P < 0.001 and 5.9 +/- 1.2 to 5.0 -/+ 1.2 mL/min per kg, P < 0.001 for hanging laundry), although the older subjects experienced less perceived exertion with the energy conservation techniques. For washing clothes, no reduction in energy expenditure was observed in either age groups. CONCLUSION: Measurable benefits were observed with use of labour-saving equipment and avoidance of overhead reaching in younger subjects only.

Activities of Daily Living↗
PubMed2005

Angiotensin converting enzyme inhibitor use is associated with higher bone mineral density in elderly Chinese.

Hypertension and osteoporosis are two major chronic diseases affecting the elderly. A cross-sectional study of 3887 Chinese men (n = 1958) and women (n = 1929) was used to explore the association between angiotensin converting enzyme inhibitor (ACEI) use and bone mineral density (BMD). The participants were aged 65 years and above, and were recruited using a combination of private solicitation and public advertising from community centers, housing estates, and the general community in Hong Kong. Demographic, medical, and lifestyle information was obtained from face to face interviews using standardized questionnaire, and physical examination measurements included anthropometry, tibial, and brachial systolic blood pressures, femoral neck, total hip, and lumbar spine BMD. In multiple regression analyses, after adjusting for age, weight, height, thiazide, beta-blocker, calcium channel blocker, statin, corticosteroid, and calcium supplement use, history of diabetes, heart disease, peripheral vascular disease, cigarette smoking, alcohol intake, and physical activity level, ACEI use was associated with higher femoral neck BMD (+0.015 g/cm2, P = 0.035) in women, and higher femoral neck (+0.015 g/cm2, P = 0.017), total hip (+0.016 g/cm2, P = 0.021), and lumbar spine (+0.043 g/cm2, P < 0.001) BMD in men. Thiazide use was associated with higher BMD at all three sites in general, although associations with BMD increase at the total hip (P = 0.07) and femoral neck (P = 0.09) were weak in men. Calcium channel blocker use was only significantly associated with BMD increase at the lumbar spine (P = 0.03) in women, and beta-blocker use did not have significant associations with BMD at any site. This study suggests that in addition to thiazide diuretics ACEI may have possible benefits in treating not only hypertension but also osteoporosis among older Chinese.

Aged↗
PubMed2005

Impaired transcriptional upregulation of Parkin promoter variant under oxidative stress and proteasomal inhibition: clinical association.

We provided data to show that the transcriptional activity of wildtype -258T in the parkin promoter region was significantly higher than the -258G variant in human cell lines. The transcriptional activity of wildtype -258T was significantly increased under oxidative stress by hydrogen peroxide, but this was not observed for the -258G variant. The transcriptional upregulation was significantly higher for wildtype -258T compared to -258G variant at 0.1, 0.2 and 0.4 mM of hydrogen peroxide. Similar results were obtained when the cells were treated with a proteasome inhibitor, MG132.Furthermore, in a case control study involving 753 subjects, we demonstrated that the parkin promoter -258G variant was associated with an increased risk of sporadic Parkinson's disease (PD) in the elderly ethnic Chinese population. Our clinical and laboratory data provide corroborative evidence that some older individuals who have the -258G variant may have a higher risk of developing PD.

Age Factors↗
PubMed2005

The determinants of bone mineral density in Chinese men--results from Mr. Os (Hong Kong), the first cohort study on osteoporosis in Asian men.

Mr. Os (Hong Kong) is the first study to address the risk factors for osteoporosis in Asian men. A standardized, structured interview and dual X-ray densitometry (DEXA) were performed on 2,000 Chinese men aged 65-92. By multiple regression, the following factors were found to be positively associated with BMD at both the total hip and the spine: body weight, grip strength and a history of diabetes mellitus. The following factors were found to be negatively associated with BMD at both the total hip and spine: cigarette smoking, a history of gastrectomy or bowel resection, current use of inhaled steroid and a history of fracture after 50 years. Moreover, a history of chronic obstructive pulmonary disease (COPD) was negatively associated with BMD at the total hip, and age, the use of an alpha-blocker, thiazide diuretic and nitrate were associated with a higher BMD at the spine. A total of 21.8% of the variance in total hip and 31.5% of the variance in total spine BMD was accounted for in the multivariate analysis.

Absorptiometry, Photon↗
PubMed2005

Unusual cases of human myiasis due to Old World screwworm fly acquired indoors in Hong Kong.

Myiasis is the infestation of tissue by the larvae of flies. We report eight cases of human myiasis in Hong Kong. All patients were nursing home residents with an average age of 81.8 years. Seven patients were bedridden with advanced dementia. Four patients had pre-existing wounds. Five had poor oral hygiene and four of those were on tube feeding. All of the five patients with poor oral hygiene suffered from oral myiasis. Two patients had vaginal infestations and one had wound myiasis in his diabetic foot ulcer. Seven cases were infested by Chrysomya bezziana, an obligatory parasite that requires living mammalian tissue for its larval development. Larvae of the Calliphoridae family were responsible for the remaining case. Patients were managed with manual removal of larvae and irrigation of the site of infestation with saline. All infestations were nosocomial, being acquired in nursing homes. Carers of the old and debilitated should be made aware of the need for better oral care, especially for those on tube feeding. The use of window screens in nursing homes should be encouraged to reduce the chance of flies entering the vicinity of these patients. Electrocuters could also be mounted indoors to kill flies that do enter.

Aged↗
PubMed2005

Correlates for a low ankle-brachial index in elderly Chinese.

This study examines the prevalence of atherosclerosis (using ankle-brachial index (ABI) value <0.9) and associated socioeconomic and lifestyle factors in elderly Chinese, adjusting for presence of cardiovascular diseases and body mass index, in a cross-sectional survey of 1999 men and 1999 women aged 65 years and over living in the community. A questionnaire containing information regarding socioeconomic status, medical history and lifestyle factors was administered. Measurement included height, weight, percentage body fat using dual-energy X-ray absorptiometry and ABI. The Hong Kong population (2000) age adjusted prevalence of ABI <0.9 was 5.3% for men and 11.0% for women. In multivariate analysis, old age, female gender, presence of cardiovascular diseases, cognitive impairment, prolonged 6 m walk, smoking habit and alcohol intake were positively associated with ABI <0.9, while negative associations were observed with Vitamin C intake >100 mg per day, with the lowest OR for the range 141-190 mg (OR 0.4). Physical activity level, and self rated higher social standing in the community, while significant in univariate analysis, were not included as independent significant factors in the multivariate model. Lifestyle factors and the female gender were independent risk factors for atherosclerosis in the elderly Chinese population.

Aged↗
PubMed2005

Comparative effect of seeds of Rhynchosia volubilis and soybean on MG-63 human osteoblastic cell proliferation and estrogenicity.

The seeds of Rhynchosia volubilis (SRV) (Leguminosae) and soybean have been used in oriental folk medicine to prevent postmenopausal osteoporosis. Their beneficial effects are caused by a high content of isoflavone, which function as partial agonists or antagonists of estrogen. To compare the estrogenic effects of SRV and soybean on the MG-63 osteoblastic cell proliferation, 70% methanol extracts of SRV or soybean were treated on MG-63 cells. Although biphasic over a concentration range of 0.001 mg/ml-0.1 mg/ml, both SRV and soybean extracts increased MG-63 cell proliferation. However SRV was more effective at increasing the cell proliferation that paralleled with the greater estrogenic effects as determined by estrogen receptor alpha (ERalpha) expression, an estrogenic response element (ERE)-luciferase activity and the selective expression of insulin-like growth factor-I (IGF-I). SRV-induced IGF-I expression resulted from increases in the mRNA levels. Despite the increased expression of ERbeta, ERE activity and IGF-I expression by soybean were lower than those by SRV. Furthermore, the comparable estrogenic effects between SRV and the combined treatment of genistein and daidzein standards at 0.5 x 10(-8) M, which is a concentration of these two isoflavones similar to that of SRV at 0.001 mg/ml, demonstrate that the greater estrogenicity of SRV for MG-63 cell proliferation is mediated by the synergism of low levels of isoflavones for the selective expression of IGF-I.

Blotting, Northern↗
PubMed2005

Bone mineral density and the risk of peripheral arterial disease in men and women: results from Mr. and Ms Os, Hong Kong.

Previous population studies have demonstrated an association between peripheral vascular disease and bone mineral density in women, but not in men. In a large prospective cohort of 3,998 Chinese men and women aged 65 to 92 years of age in Hong Kong, the association between peripheral vascular disease and bone mineral density was explored. Demographic and lifestyle information was obtained from face to face interviews using a standardized questionnaire. This included demographic information, medical history and lifestyle factors. Physical examination measurements included anthropometry and tibial and brachial systolic blood pressures. The ratio of the posterior tibial and brachial systolic blood pressures, the ankle/arm index, was used as a measure of peripheral arteriosclerosis in the lower extremities. Bone mineral density (BMD) at the total hip and spine (L1-L4) was measured by Hologic QDR-4500 W densitometers (Hologic, Inc., Waltham, Mass.). In this cross-sectional analysis, the ankle brachial index (ABI) was positively correlated with hip BMD (correlation coefficient=0.27; P<0.001). However, after adjustment for confounders, the correlation became much weaker (correlation coefficient=0.03; P<0.05). This showed that much of the relationship between ABI and BMD could be explained by other confounders. In multiple regression analysis, an increase in ABI of 1 SD of ABI was associated with an increase of 0.5% (95% CI: 0.02%, 0.9%) in hip BMD after adjusting for age, sex, body weight, smoking status, history of diabetes, cardiovascular diseases, use of thiazide diuretics, grip strength and physical activity. Although our study shows that peripheral vascular disease in the lower extremities may be associated with decreased bone mineral density, the association is weak especially after adjustment was made for confounders. This indicates that other factors may be contributing to the association between peripheral vascular disease and osteoporosis.

Aged↗
PubMed2005

Depression is the predominant factor contributing to morale as measured by the Philadelphia Geriatric Morale Scale in elderly Chinese aged 70 years and over.

OBJECTIVE: To examine factors contributing to the total Philadelphia Geriatric Morale Scale (PGMS) and its two subscales: reconciled ageing and unstrained affect. METHOD: The PGMS was administered to 759 community-living subjects aged 70 years and over. Information regarding socioeconomic status, health conditions, sensory impairment, physical symptoms, social support, activities of daily living as measured by the Barthel Index, life satisfaction, and the Geriatric Depression Score, was collected. Associations between these factors and PGMS and its subscale were examined using univariate analysis (Mann-Whitney; Kruskal-Wallis tests), and multivariate analysis using the classification and regression tree (CART) method. RESULTS: Gender, old age, physical, socioeconomic and social factors were significantly associated with PGMS. There was a strong correlation with GDS (r = 0.77, p < 0.001). In the CART analysis, for both subscales and the total score, GDS was the predominant factor contributing to the score. Other factors include self perception of health, enough expenses, overall satisfaction with life, gender, and constipation. DISCUSSION: The PGMS and GDS are closely related. In addition to the GDS, health perception, life satisfaction, and adequate finance were factors contributing to quality of life in elderly Hong Kong Chinese.

Activities of Daily Living↗
PubMed2005

Low staffing level is associated with malnutrition in long-term residential care homes.

OBJECTIVE: To determine if staffing level is associated with poor nutrition in the long-term residential care setting, adjusting for other confounding factors. DESIGN: Cross-sectional survey. SETTING: In total, 14 residential care facilities in Hong Kong, stratified by nature (government subvention or for-profit) to reflect the overall proportion in Hong Kong. SUBJECTS: A total of 1914 subjects were assessed, using the Resident Assessment Instrument (RAI) 2.0. The response rate was 95% (1820 subjects), of which 1699 subjects had complete nutritional information. INTERVENTION: Body mass index (BMI) was calculated by weighing and height measurement, and arm span was used if the subject could not stand. Subjects who were receiving parenteral or enteral nutrition via nasogastric of enterostomy tubes were excluded. A history of weight loss of 5% in the past month or 10% in the past 6 months, leaving 25% of food uneaten, and BMI < 18.5 kg/m(2) were examined as nutritional indicators. Association with age, gender, functional disability, oral problems, taste problems, presence of physical diseases and psychological well-being was examined using chi(2)-test, and multiple logistic regression. RESULTS: In all, 26% of residents had a BMI < 18.5 kg/m(2), with a higher prevalence in the for-profit homes. History of weight loss and the record that 25% of food was left uneaten were poor indicators of low BMI. Multivariate analysis showed that having chronic obstructive airways disease, requiring help with feeding, being female, older age, were factors associated with an increased risk of poor nutrition, while being independent in activities of daily living and higher staff levels were associated with a reduced risk. CONCLUSION: Poor nutrition is a persistent problem in the long-term care setting, and inadequate staffing levels may be a reversible cause. However, resource limitations may render efforts at improvement difficult. SPONSORSHIP: SK Yee Memorial Fund.

Age Factors↗
PubMed2004

Benefits of milk powder supplementation on bone accretion in Chinese children.

Low dietary calcium intake has been demonstrated to be a risk factor for hip and vertebral fractures in studies conducted among Hong Kong Chinese. Few studies have demonstrated the effect of milk supplementation in bone accretion in Chinese children. The aim was to examine the effects of milk powder supplementation in enhancing bone accretion in Chinese children. Three hundred and forty-four children, aged 9-10 years old, were randomized to receive milk powder equivalent to 1300 mg and 650 mg calcium, and to a control group, respectively. Bone mineral density (BMD) at the proximal femur, lumbar spine and total body were measured at 6 months, 12 months and 18 months. The treatment effects were modeled using linear mixed effect models and compared using linear contrast F-tests, by intention-to-treat. Subjects randomized to milk powder equivalent to 1300 mg calcium had significantly higher increase in BMD at both the total hip (7.4 +/- 0.4% in treatment group versus 6.3 +/- 0.4% in the control) and the spine (8.4 +/- 0.5% in the treatment group versus 7.0 +/- 0.5% in the control group). Subjects randomized to milk powder equivalent to 650 mg calcium had smaller increases in BMD at the total hip and spine, although the increase in BMD at the total body was significantly higher (3.1 +/- 0.3% in treatment group versus 2.4 +/- 0.2% in controls). It is concluded that supplementing the diet of Chinese children with milk powder was effective in enhancing bone accretion.

Animals↗
PubMed2004

The relationship between COLI A1 polymorphisms (Sp 1) and COLI A2 polymorphisms (Eco R1 and Puv II) with bone mineral density in Chinese men and women.

Polymerase chain reaction was used to amplify across variable restriction sites of the COLI A1 and COLI A2 genes that encode the alpha 1 and 2 subunits of type I collagen. The relationship between these polymorphisms and bone mineral density (BMD) was studied in 683 Chinese men and women. In 100 men and women, COLI A1 Sp1 polymorphism was not found, which was consistent with other previous studies in Asian populations. However a statistically significant relationship was observed between COLI A2 Eco R1 and Puv II genotypes among the Chinese men studied. The mean BMD was consistently lower in men of the EE and PP genotype (P < 0.05 by analysis of variance [ANOVA]) than in men of the ee and pp genotypes. However, no association between BMD and the Eco R1 or Puv II genotypes was observed in Chinese women (P > 0.05 by ANOVA). We conclude that the COLI Al Sp1 binding site is absent in Hong Kong Chinese, whereas the COLI A2 Eco R1 and Puv II genetic polymorphisms may be associated with the BMD of elderly Chinese men.

Age Factors↗
PubMed2004

Methylenetetrahydrofolate reductase polymorphism (MTHFR C677T) and bone mineral density in Chinese men and women.

The relationship between MTHFR (C677T) genotypes of the methylenetetrahydrofolate reductase, bone mineral density (BMD), and vertebral fracture was studied in 657 Chinese men and women. No association between MTHFR (C677T) and BMD was found in postmenopausal women (aged 55-59 years, n=178), elderly women (aged 70-79 years, n=247), or elderly men (aged 70-79 years, n=232) at the hip, spine, or total body (P >0.05 by ANCOVA). In all study groups, there was no effect of an interaction between MTHFR (C677T) and daily dietary calcium intake on BMD (P >0.05 for the interaction effects by two-way ANCOVA). No statistically significant association was observed between MTHFR (C677T) genotypes and vertebral fracture. The MTHFR (C677T) genotypes for CC, CT, and TT among elderly women with or without vertebral fracture were 5%, 33%, 62%; 6%, 37%, and 57%, respectively, and those for elderly men with and without vertebral fracture were 9%, 31%, 60%; 5%, 35%, and 60%, respectively. The prevalence of TT in our study group was 5% compared to 8% in the Danish or 18.6% in the Japanese. We found no association between MTHFR (C677T) and BMD of Chinese men or women. It would be interesting to study the interactions with folate, B12, and homocysteine.

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