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Biomedical subjects

J Woo

Publications and source records attributed to J Woo.

At least 397 records · Page 22Linked to original sources
PubMed1972

A study of the cell surface of tumour, foetal and lymph-node cells by cell electrophoresis after antibody and enzymic treatment.

1. Rabbit anti-(rat foetal liver) serum, absorbed with adult rat liver cells, decreased the electrophoretic mobility of foetal liver cells by 51% and rat hepatoma cells by 45%, indicating the presence of a foetal-type antigen on the hepatoma cell membrane. 2. The chemical nature of the surface antigen was investigated. Incubation with neuraminidase had no effect on adult liver cells but decreased the electrophoretic mobility of foetal liver cells by 51% and of hepatoma cells by 34%; the effect of antiserum was decreased to one-fifth. 3. Sialic acid, or the supernatant from neuraminidase-treated cells, partially blocked the decrease in electrophoretic mobility induced by antiserum. 4. The pH-electrophoretic mobility curves of hepatoma cells treated with antisera were consistent with a sialic acidcontaining antigen on the surface of the tumour cells. 5. Treatment with ribonuclease did not decrease the electrophoretic mobility of adult-liver cells, but decreased that of the foetal liver cells by 17% and hepatoma cells by 29%. 6. In parallel studies made with mouse BP8 ascites-tumour cells ribonuclease decreased the electrophoretic mobility by 39%, that of normal mouse lymph-node cells by 4.8% and allergized mouse lymph-node cells by 13.3%. 7. Trypsin treatment also decreased the electrophoretic mobility of hepatoma cells by 22%.

Animals↗
PubMedDate not supplied

Alleviation of cyclosporin-induced immune suppression by the cytokine inducer ADA-202-718.

ADA-202-718 (ADA) has been shown to augment the production of various cytokines (IL-1, IL-2 and gamma-interferon) by murine T lymphocytes. Administration of 1 mg/kg/day to mice from the time of immunization significantly enhanced delayed-type hypersensitivity responses to sheep red blood cells (SRBC). ADA also inhibited immune suppression in mice given 25 but not 50 mg/kg/day cyclosporin A (CsA). There were, however, few changes compared with vehicle-treated controls in the numbers of splenic regulatory T cell subsets (L3T4+ and Ly2+) following treatment with CsA, ADA or both drugs. On the other hand, splenic lymphocytes from ADA-treated animals exhibited augmented proliferative responses to polyclonal T and B cell mitogens and antigen. ADA (1 mg/kg) also stimulated the splenic IgM plaque-forming cell response to SRBC and prevented CsA (25 mg/kg)-induced suppression of humoral immunity. In vitro, ADA (2 micrograms/ml) inhibited CsA-induced suppression of T cell proliferation, the effect being most marked at lower inhibitory concentrations of CsA. These data illustrate the capacity of ADA to augment or restore T cell responses in experimental animals and are consistent with the view that CsA acts in these experimental in vivo systems by inhibition of cytokine production.

Animals↗
PubMedDate not supplied

Evaluating elderly patients with syncope.

Age-related physiologic changes together with high prevalence of chronic illness and the use of multiple medications predispose older adults to syncope. The causes of many of these patients' syncope are unexplained and most remained symptomatic. A thoughtful diagnostic strategy is essential to pinpoint the cause in each patient. The initial assessment includes a comprehensive medical history, preferably with an eye witness account, and a thorough physical examination. The decision for further diagnostic tests often depends on whether there is evidence of underlying structural heart disease. In the absence of heart disease, tilt table testing and the related autonomic function testing are usually most productive. Various cardiac studies will be more appropriate for those with suspected structural heart disease. A cause of syncope can only be concluded if there is a sufficiently strong correlation between syncopal symptoms and the detected abnormalities on investigations. A strategic evaluation of syncope of the elderly subjects should allow a correct diagnosis and appropriate management.

Journal Article↗
PubMedDate not supplied

The influence of income on morbidity, mortality and dependency in elderly Hong Kong Chinese.

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.

Journal Article↗
PubMedDate not supplied

Simultaneous measurement of 19 components in serum-containing animal cell culture media by fourier transform near-infrared spectroscopy.

Animal cell cultures generate maximal amounts of desired products when maintained in a controlled environment with low and constant concentrations of nutrients and wastes. Traditionally this has involved slow addition of glucose and glutamine; however, recent studies have indicated that a number of low concentration amino acids are required to prevent initiation of apoptosis. Therefore, optimal control of animal cell cultures will likely require measurement of a large number of chemical components. We present here the evaluation of a near-infrared spectroscopic (NIRS) monitoring scheme to quantify 19 cellular nutrients and wastes in culture medium with and without serum. The components include glucose, lactate, ammonia, pyruvate, glutamine, and 14 other amino acids. Spectroscopic calibrations were generated for a synthetic version of a standard culture medium (DMEM) in which the concentrations of 17 DMEM components and ammonia and lactate were varied in a random fashion. This randomization provides a stringent evaluation of the measurement scheme. Reasonably accurate measurements of these 19 components could be accomplished in the absence or presence of 10% horse serum by volume with percent errors ranging from 3% to 37%. Analytes with concentrations as low as 0.3 mM could be reliably quantified. The presence of serum, when properly included in the calibration, has little effect on measurement error. These results provide an important step toward application of NIRS for monitoring the large number of varying components of animal cell cultivations.

Amino Acids↗
PubMedDate not supplied

The prediction of height by armspan in older Chinese people.

OBJECTIVE: To compare the accuracy of the predictive equations derived from older Chinese people without vertebral deformity with those derived from unselected older people, in estimating height from armspan. METHODOLOGY: Height and armspan were measured in 789 older Chinese and 885 young Chinese in Hong Kong. All the older subjects had spinal X-ray (T4 to L4). Vertebral deformity was determined by a trained technician using a translucent digital analyser. Definite deformity was defined by a greater than 3 standard deviation increase in one of the three vertebral height ratios (anterior/posterior, middle/posterior and posterior/posterior). Eighty of the older subjects without vertebral deformity were randomly selected from the studied population for internal validation of predictive equations. The remaining subjects were used to derive sex-specific predictive equations for height by linear regression against armspan. The accuracy of these equations was analysed by the Bland and Altman method. RESULTS: Vertebral deformity was present in 30.7% and 15.6% of older female and male subjects, respectively. Older women without vertebral deformity had significantly greater armspan: height ratio when compared with the young (1.04 versus 1.02), but the corresponding ratios were the same in older and young men (both 1.04). The predictive equation derived from older females without vertebral deformity had lower standard error of estimation and gave estimates closer to measured height than those derived from unselected older women. But this was not the case in older men. CONCLUSION: In deriving predictive equation to estimate height by armspan in older Chinese women, selecting out older women without vertebral deformity increased accuracy of the equation. This was, however, not the case in older men.

Adolescent↗
PubMedDate not supplied

Pheochromocytoma in dogs: 61 cases (1984-1995).

This report presents the clinical, laboratory, imaging, and pathologic findings in 61 dogs with pheochromocytoma by retrospective evaluation of medical records. Pheochromocytomas were diagnosed by histopathologic examination of tissue specimens in all dogs. Special stains (chromogranin A and synaptophysin) also were used to confirm the chromaffin cell origin of the tumors. Epidemiologic findings were in agreement with previous studies, indicating that pheochromocytomas affect middle-aged to older dogs with no apparent gender or breed predilection. The tumor was considered clinical in 21 dogs (34%), was responsible for abnormalities related to a space-occupying mass in 7 dogs (11%), and was an incidental finding in 35 dogs (57%). The hematologic and biochemical findings were nonspecific. Hypertension was detected in 10 of 23 (43%) dogs tested, but all hypertensive dogs had concurrent diseases that may have contributed to hypertension. Abdominal ultrasonography was the most commonly used imaging procedure, with a mass detected in the region of the adrenal glands in 20 of 40 (50%) dogs examined. In 4 of the 20 dogs (20%), invasion of the caudal vena cava was identified. Surgery was performed in 17 dogs (28%) with immediate death or euthanasia of 5 dogs. Survival after surgery ranged from 1 day to 3.25 years. Pheochromocytomas were locally invasive in 39% of affected dogs and produced metastases in 13% of the cases. Common sites for metastases included regional lymph nodes, liver, lung, kidney, spleen, and bone. A high frequency of concurrent neoplasia (54%), including endocrine neoplasia, was identified.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Telemedicine: a pilot study in nursing home residents.

BACKGROUND: Telemedicine has been applied successfully in various fields of medicine. This mode of health care delivery may potentially be useful in supporting frail nursing home residents who require multidisciplinary geriatric services. OBJECTIVE: To assess the feasibility of telemedicine in providing geriatric services to nursing home residents, and whether this mode of care resulted in increased productivity and savings. METHODS: A local 200-bed nursing home supported by the Community Geriatric Assessment Team (CGAT) was recruited. Over a 1-year period, teleconferencing was used to replace conventional geriatric outreach services. The feasibility of telemedicine was evaluated by participating specialists. Productivity gains, consumption of hospital services and user satisfaction were measured. RESULTS: Telemedicine was adequate for service delivery in up to 99% of cases, depending on the specialty. A greater number of clients were served and follow-up intervals were shortened. The service was cheaper than conventional outreach or clinic activities, and acceptable to users and clients. In particular, savings were made through a 9% reduction in visits to the Accidents and Emergency Department and in 11% fewer admissions to acute hospital wards. CONCLUSION: telemedicine is a feasible means of delivering multidisciplinary care to frail nursing home residents, and may result in increased productivity and significant savings.

Aged↗
PubMedDate not supplied

Lifestyle factors and health outcomes in elderly Hong Kong chinese aged 70 years and over.

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.

Aged↗
PubMedDate not supplied

Social determinants of frailty.

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.

Aged↗
PubMedDate not supplied

Serum lipid profile in an elderly Chinese population.

The serum lipid profile of a cohort of Hong Kong Chinese subjects living in the community (160 men, 154 women, mean age 70.2 +/- 11.4 years) was examined to determine the influence of age, sex, indices of obesity, drugs, smoking, alcohol intake, and presence of diabetes mellitus on serum lipid, lipoprotein, and apolipoprotein concentrations. A high waist/hip ratio (an index of central obesity) was associated with higher serum triglyceride and lower apolipoprotein (apo) A-I concentrations, while a higher body mass index was associated with lower high density lipoprotein (HDL) cholesterol and higher apo B concentrations. Smokers and those taking beta-blockers had lower apo A-I concentrations. Subjects on methyldopa had higher triglyceride and very low density lipoprotein cholesterol, with lower HDL and HDL2 cholesterol. All the HDL fractions were lower in diabetic subjects, and cholesterol and triglyceride concentrations correlated with indices of glycemic control.

Age Factors↗
PubMedDate not supplied

A new canine model of proximal internal carotid embolism.

A new model of internal carotid artery embolism was developed using autologous clot. The clot was prepared by incubating blood at room temperature for 2 hours to inactivate plasminogen activators and then refrigerating it at 4 degrees C for 22 hours. The purpose of the experiment was to devise a model of the intravascular lesion and not of stroke itself. The dog was chosen as the experimental animal since it has a maxillocarotid artery which permits collateral flow beyond proximal internal carotid artery occlusions. A volume of clot measuring 0.25 to 0.30 cc was sufficient to occlude the artery for 48 hours in 80% of the animals without causing major strokes. We have used this model to study clot radiolabeling and suggest it may also have application for evaluating thrombolytic drugs.

Animals↗
PubMedDate not supplied

A double-blind randomised comparison of perindopril and ketanserin in the treatment of hypertension in elderly diabetic patients.

A double-blind, randomised study of the antihypertensive efficacy of perindopril and ketanserin in 44 elderly noninsulin-dependent diabetic patients aged > or = 60 years was conducted. Blood pressure, blood biochemical and haematological parameters, plasma vasoactive hormones, urinary volume, electrolytes and microalbumin were measured at baseline, after a 4-week placebo period, and at intervals during 8 weeks of treatment with active drug. Electrocardiogram and echocardiogram data were also obtained. Dosages of perindopril used were 2 mg once daily for 4 weeks doubling to 4 mg once daily if a target blood pressure of < or = 160/90 mm Hg was not reached. Dosages of ketanserin were 40 mg twice daily increasing to 80 mg twice daily. Both drugs caused a small but statistically insignificant reduction in blood pressure. Although the response rates (supine systolic blood pressure reduction of > 10 mm Hg) were 54% for perindopril and 45% for ketanserin, target blood pressure (supine blood pressure 160/90 mm Hg) was reached in only 21% of perindopril and 20% of ketanserin recipients. Plasma creatinine and 24-hour urine sodium excretion increased in patients receiving ketanserin therapy. Glycaemic indices and the lipid profile did not change in either group, except for a reduction in plasma triglycerides in the ketanserin group. No changes in urinary microalbumin, electrocardiogram, or echocardiographic cardiac parameters were observed. It is concluded that in the present study neither drug provoked a significant blood pressure lowering effect and that serum creatinine increased in the ketanserin group.

Aged↗