Biomedical subjects
Publications and source records attributed to S C Ho.
A survey of 19 voluntary institutions providing Chinese traditional medical services in Singapore investigated their organisation, the types of medical services provided, patient volume, and the characteristics of the physicians working there. This paper reports on the findings of the survey.
The endocytosis of large unilamellar liposomes composed of phosphatidylcholine by the cultured Chinese hamster V-79 cells is demonstrated with electron microscopy cytochemistry. A novel cytochemical marker, 5-Br,4-Cl,3-indolylphosphate (BCIP) is used. This marker is a soluble and colorless substrate for the lysosomal acid phosphatase and can be readily entrapped in liposomes. The product of the enzymatic reaction, 5-Br,4-Cl,3-hydroxy indole, rapidly self-condenses and becomes an insoluble derivative of indigo blue. In thin section transmission electron microscopy, the condensed product appears as electron-dense deposits in the lysosomes. Since the electron-dense deposit only appears when the endocytosed liposomes are delivered to the lysosomes as the result of phagosome-lysosome fusion, this marker provides a unique cytochemical means to reveal those liposomes that are lysosomotropic and are actually decomposed within the lysosomes. No electron-dense deposits are found in the liposome-treated cells in the presence of chloroquine, or a combination of NaN3 and deoxyglucose. As a comparison, we have also used horseradish peroxidase entrapped in liposomes to confirm the endocytic uptake of liposomes. Using a radioactive marker, 125I-labeled lysozyme, entrapped in liposomes, it is shown that about 20-30% of liposome uptake by V-79 cells is due to endocytosis.
Five forms of renin, A0, A, C, D and E, from mouse submaxillary gland were purified by a two-step procedure including chromatography on the immunoaffinity column and CM-cellulose column. Four renin fractions, A0, A, C and E were purified to homogeneity by the criteria of polyacrylamide gel electrophoresis, analytical isoelectric focusing and Ouchterlony double immunodiffusion. All these forms of renin have molecular weights of 40 000 as determined by gel filtration on Sephadex G-100 column. No high molecular weight renin could be demonstrated. Individual renin fractions showed similar angiotensin I formation activity, 52-158 ng angiotensin I/ng protein per h. No other protease activity could be detected with hemoglobin or casein as substrate. These purified proteins showed a discrete pattern of migration under polyacrylamide gel electrophoresis. Under denaturing condition in SDS-gel electrophoresis, all but fraction D showed a protein band with a molecular weight of 30 000. Fraction D showed a major component with molecular weight of 33 000. The isoelectric points of these renin forms varied from 5.46 to 5.76. They all reacted with antibody raised against renin A and showed similar pressor response activity with 20 ng quantities of the purified proteins. The closely related characteristics of these five forms of renin were further demonstrated by their similarity in peptide mapping patterns after limited digestion with Staphylococcus aureus V8 protease. The data suggest that these proteins are homologous proteins.
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Chlorite, a by-product of chlorine dioxide disinfection of water, is a strong oxidant compound that produces markedly exaggerated effects in vitro on red cells of G6PD deficient humans when compared to normal human cells. Levels of methemoglobin are significantly greater and GSH levels significantly lower in the G6PD deficient cells than in normal cells after chlorite exposure. Persons with G6PD deficiency may be 3 to 4 times more likely to develop hemolytic anemia from chlorite exposure as persons with normal activity levels when GSH levels are used as a measure of susceptibility. The proposed use of chlorine dioxide as an alternate disinfectant for drinking water supplies should consider this potential high risk group.
Emulsifiable concentrates of DursbanR (chlorpyrifos) and Dowco 214 (chlorpyrifos-methyl) were tested as mosquito larvicides using Hudson knapsack sprayers on small plots of rice-fields on Penang Island. The mosquitoes found in these rice-fields are predominantly Anopheles campestris and Culex tritaeniorhynchus. At dosages of 14, 28 and 56 gm hectare-1, Dursban is effective in maintaining the rice-fields free of Anopheles larvae for at least 2, 3 and 7 days respectively. Dowco 214 at 56 gm hectare-1 is able to keep the fields free of all mosquito larvae for at least 2 days.
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The association between income and mortality, morbidity and dependency is examined in a 3-year prospective follow-up study of 2032 subjects aged 70 years and above in the Hong Kong Special Administrative Region, China. Subjects were recruited using stratified disproportional random sampling of the Old Age and Disability Allowance Schemes, covering over 90% of the population. Subjects were interviewed at baseline and after 36 months. Presence or absence of disease was based on self-report of doctor diagnosis together with a check of medication taken. Functional status was measured using the Barthel Index. For the disease analysis, subjects with the disease being analyzed at baseline were excluded; similarly for the dependency analysis, subjects who were dependent at baseline were excluded. Chi-square test, univariate and multiple logistic regression were used to examine the association between income and mortality, development of new disease, and dependency. There was no association between income and mortality, or with development of new disease. Development of dependency was associated with lower income at baseline. An income of less than 1000 HK dollars per month increased the risk of dependency by 1.8-fold (95%CI 1.1-2.9). However, this association disappeared after adjustment for age and sex. Absolute income is not an important factor contributing to mortality, morbidity and dependency in elderly Chinese aged 70 years and above. A freely accessible health and social service at low or no cost, the survivor effect, or other factors may account for the lack of association with income, contrary to findings from studies of whole populations worldwide. Therefore manipulating income alone is unlikely to affect these outcomes in the elderly.
BACKGROUND AND OBJECTIVES: The association of human papillomavirus (HPV) infection with cervical carcinoma is well documented. The HPV types in cervical lesions of patients from Taiwan are analyzed by the polymerase chain reaction (PCR). STUDY DESIGN: DNA was extracted from paraffin-embedded, formalin-fixed tissues using a sonication method. PCR was performed using type-specific primers for the presence of HPV types 6, 11, 16, 18, 31, and 33 DNA. Amplified product was subjected to gel electrophoresis and Southern blot hybridization analysis. RESULTS: A total of 129 cervical lesions and normal cervical biopsies were examined. Histologic examination revealed a spectrum of lesions, which were classified as condyloma acuminata (AC), condyloma (CL), koilocytosis (KL), various grades of cervical intraepithelial neoplasia (CIN I, II, and III), carcinoma in situ (CIS), and invasive carcinoma (ICa). Of 114 cervical lesions, 65% (26 of 40) of AC; 61% (11 of 18) of CL; 20% (2 of 10) of KL; 25% (1 of 4) of CIN I; 69% (9 of 13) of CIN II; 80% (12 of 15) of CIN III; 83% (5 of 6) of CIS; and 100% (8 of 8) of ICa were positive for at least one type of HPV by the PCR. Among the 74 HPV-positive specimens, 19 (26%) were detected with multiple types. HPV DNA was detected in the cervical biopsies of 1 of 15 (6.7%) normal individuals. CONCLUSION: Excluding AC, HPV 6 and/or 11 (HPV 6/11), HPV 16 and/or 18 (HPV 16/18), and HPV 31 and/or 33 (HPV 31/33) were detected in 40% (19 of 48), 71% (34 of 48), and 12% (6 of 48) of neoplastic lesions of patients from Taiwan respectively. These findings are compatible with those reported by others worldwide.
A retrospective study of 672 sampled records of patients of a major institution providing Chinese traditional medicine in Singapore reveals that 97.3% of the patients were Chinese, with a dialect group distribution following closely that of the Singapore Chinese. The male-to-female patient ratio was 1.0:1.13. There were fewer patients of the pediatric age group and more of those from age 30 upwards. Some 43% of the patients sought treatment for "infective" and "internal, emotional and weakness" diseases. The prevalent disease conditions seen among patients from the different age groups are also analyzed and discussed in this paper.
BACKGROUND: Although increasing emphasis is being placed on strategies for successful aging, few studies have examined the relationship between lifestyle factors and mortality and other health outcomes in the old-old population. OBJECTIVE: To examine the impact of physical activity, dietary habits, smoking, and alcohol consumption on 3-year mortality and other health outcomes. METHODS: 2,032 Chinese subjects aged 70 years and older (mean age 80 years) were recruited territorywide by proportional random sampling and followed for 3 years. Baseline information was obtained by interview on level of physical activity, dietary habits (frequency of consumption per week of major food groups), alcohol consumption, and smoking habits. Outcome measures include mortality, self-perceived health status, frequency of hospitalization, geriatric depression score, and development of new diseases (stroke, heart disease, hypertension, diabetes mellitus, fractures). Logistic regression was used to examine the effects of lifestyle factors on each health outcome, with and without adjustment for age and baseline health status. RESULTS: The mortality risk is reduced with increasing physical activity, daily fish intake and moderate alcohol consumption, and avoidance of smoking; hospitalization is inversely associated with increasing activity; better self-perceived health is associated with moderate alcohol consumption and a non-smoking status, and there is an inverse relationship between depressive symptoms and increasing activity and moderate alcohol consumption. After adjustment for age and baseline health status, higher levels of physical activity are associated with decreased mortality and hospitalization; non-smokers have reduced mortality and a better self-perceived health, and moderate alcohol consumption is also associated with better self-perceived health. CONCLUSION: Lifestyle factors may influence health outcomes even in the old-old population.
BACKGROUND: Frailty represents a body-wide set of a linked deterioration that occurs with ageing, but is susceptible to active intervention and is reversible. The concept of frailty should include broader environmental factors. A quantitative measure of frailty, the frailty index (FI), developed for elderly Canadians and shown to be valid for an elderly Chinese population, was examined for its association with socioeconomic, lifestyle, and social support network factors in an elderly Chinese cohort. OBJECTIVE: 2,032 people aged 70 years and over recruited by stratified random sampling of the population were surveyed in 1990-1991, and information obtained regarding physical and functional health, psychological factors, lifestyle, socioeconomic and social support factors. The FI was constructed from 62 variables covering cognitive, psychological and physical health, and tested for association with socioeconomic, lifestyle and social support factors using ANOVA and t test. RESULTS: The mean FI for women was higher than for men (0.16 +/- 0.08, n = 1,033 vs. 0.13 +/- 0.08, n = 999, p < 0.001, t test). For men, increasing frailty was observed with non-white collar occupations, inadequate expenses, no or little exercise, abstinence from alcohol, few relatives or neighbours and no or infrequent participation in helping others. For women, little contact with relatives (rather than number of relatives), and absence of participation in community/religious activities were additional factors. CONCLUSION: FI is influenced by social and environmental factors in keeping with the concept of frailty being multi-dimensional. Such a quantitative measure may be a useful indicator of the health of elderly populations as well as for public health measures to combat frailty.
Singapore, located in South-east Asia, enjoys a high standard of health care. However, certain diseases are still of major concern to the health authorities, who feel these could be more easily controlled if the public were more aware of their modes of transmission. A "Combat infectious diseases" campaign was therefore launched to educate the public on food-borne diseases (cholera, enteric fever), malaria, dengue/dengue haemmorrhagic fever, leprosy, tuberculosis, and sexually transmitted diseases (syphilis, gonorrhoea). Educational activities in the form of talks, film shows and exhibitions in schools, community centres and other institutions were carried out over a 15-month period. This paper analyzes some of the factors which affected the results of the campaign, as revealed by a health survey conducted in a selected lower-middle income urban community, where sub-groups of the adult population (aged above 15) were tested to assess their health knowledge. Findings indicate that educational level, age of respondents and language proficiency--four languages are used in Singapore--seem to be the three variables that affect the likelihood of the respondents' receptivity to campaign information.