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Biomedical subjects

J Woo

Publications and source records attributed to J Woo.

At least 289 records · Page 16Linked to original sources

Environmental temperature and stroke in a subtropical climate.

The effect of environmental temperature on stroke occurrence in a subtropical climate was studied over a 1-year period by documenting the number of strokes (subdivided into cerebral infarct and intracerebral hemorrhage) admitted into a district hospital in Hong Kong at different temperatures. There was no significant correlation between the number of strokes (or its subtypes) per day per temperature category and the environmental minimum or maximum temperature. However, an association was present between the occurrence of cerebral infarcts and maximum temperature on the day of onset in elderly patients aged 70 years and above. Environmental temperature is not a strong risk factor for the occurrence of stroke in a subtropical climate.

Age Factors↗

Hypertension, lipoprotein(a), and apolipoprotein A-I as risk factors for stroke in the Chinese.

We analyzed the serum concentrations of lipids and lipoproteins and the prevalence of other risk factors in a case-control study of 304 consecutive Chinese patients with acute stroke (classified as cerebral infarction, lacunar infarction, or intracerebral hemorrhage) and 304 age- and sex-matched controls. For all strokes we identified the following risk factors: a history of ischemic heart disease, diabetes mellitus, or hypertension; the presence of atrial fibrillation or left ventricular hypertrophy; a glycosylated hemoglobin A1 concentration of greater than 9.1%; a fasting plasma glucose concentration 3 months after stroke of greater than 6.0 mmol/l; a serum triglyceride concentration 3 months after stroke of greater than 2.1 mmol/l; and a serum lipoprotein(a) concentration of greater than 29.2 mg/dl. We found the following protective factors: a serum high density lipoprotein-cholesterol concentration of greater than 1.59 mmol/l and a serum apolipoprotein A-I concentration of greater than or equal to 106 mg/dl. The patterns of risk factors differed among the three stroke subtypes. When significant risk factors were entered into a multiple logistic regression model, we found a history of hypertension, a high serum lipoprotein(a) concentration, and a low apolipoprotein A-I concentration to be independent risk factors for all strokes. The attributable risk for hypertension was estimated to be 24% in patients aged greater than or equal to 60 years. In this population, in which cerebrovascular diseases are the third commonest cause of mortality, identification of risk factors will allow further studies in risk factor modification for the prevention of stroke.

Apolipoprotein A-I↗

The radiological (CT) and clinical sequelae of primary intracerebral haemorrhage.

To determine the radiological and clinical outcome of primary intracerebral haemorrhage, a prospective study was carried out involving computed tomography (CT) of 388 consecutive Chinese patients admitted with acute stroke to a large public hospital in Hong Kong. Further CT and functional assessment were performed 3 months later in 71% of survivors. The patients were admitted over a 6 month period. 120 (31%) were found to have had presumed primary intracerebral haemorrhage. Of these, 64 patients (53%) died within 3 months. From 40 of the 56 survivors who returned for a follow-up study at 3 months, 30 were functionally independent and five mildly disabled; only five were significantly disabled. Follow-up CT showed no residual lesion in 27%, low attenuation areas in 37%, slit-like lesions in 25% and calcification in 10% of patients. The size of residual lesions correlated statistically with the degree of residual disability, although the association was not close. It is concluded that primary intracerebral haemorrhage accounts for a high percentage of strokes among Hong Kong Chinese with more than half of the patients dying within 3 months. Many survivors, in whom follow-up CT appearances are variable, show good functional recovery.

Activities of Daily Living↗

A high incidence of cough associated with combination therapy of hypertension with isradipine and lisinopril in Chinese subjects.

The efficacy and tolerability of combination therapy using Lisinopril (5-20 mg om) and Isradipine (1.25 mg-2.50 mg bd) was assessed in 29/50 Chinese subjects, whose blood pressures were not controlled on Isradipine alone. The addition of Lisinopril produced approximately two-fold reductions in blood pressure compared to Isradipine alone, increasing the responder rate of the original cohort of 50 subjects by 18% and normalization rate, by 32%. No significant changes in haematological or biochemical parameters, CXR or ECG, were observed. However, use of Lisinopril in our subjects was associated with a high incidence of cough (48%), possibly limiting its use in this population.

Adult↗

A comparison of the nutritional status of elderly Chinese living in different types of non-acute care institutions in Hong Kong.

The nutritional status of 191 elderly subjects living in three types of non-acute care institutions was studied by estimating nutrient intake and biochemical status. The dietary intake of women in the long-stay institution was similar to that of free-living elderly subjects. Dietary consumption of subjects living in a private nursing home and a convalescent unit were poorer than for elderly free-living subjects. Elderly women in all institutions had a poorer protein nutritional status, a poorer biochemical status of vitamin B12, folate, ascorbic acid, and vitamin D, and lower plasma potassium levels when compared with free-living elderly women. Those in the private nursing home and the convalescent unit had the poorest protein nutritional status. Among men, institutionalized subjects were observed to have poorer thiamine and riboflavine status, in addition to the above findings. The greater prevalence of chronic diseases and disability in the convalescent unit and the private nursing home may partly account for the poorer nutritional status of residents in these two institutions.

Aged↗

Plasma osmolality in an elderly population.

Plasma osmolality was calculated for 303 subjects (152 male and 151 female; mean age 70 +/- 11 years) living in the community. The distribution was normal, and it was not influenced by age, sex, smoking, alcohol intake or use of diuretics. The mean and 95% CI from this study were very close to the reference range given in the Geigy Scientific Tables. Higher values of mean plasma osmolality and wider 95% CI found in previous studies of unselected elderly subjects may simply reflect the higher prevalence of diseases in the elderly.

Age Factors↗

The disposition of antituberculous drugs in plasma of elderly patients. I. Isoniazid and hydrazine metabolite.

The plasma profiles of isoniazid (INH) and hydrazine (HYD) metabolite were compared in 18 elderly patients (67-89 years of age) and 19 young adult patients (19-59 years of age) on the first day and at one month after treatment for tuberculosis with INH, rifampicin (RIF) and pyrazinamide (PZA). There was no difference in the pharmacokinetics of INH between the two age groups. The clearance for INH at steady-state was significantly lower than after the first dose. After the first dose the maximum concentration (Cmax) for HYD was significantly higher (p less than 0.05) in the elderly (0.4 +/- 0.07 microgram/ml) than in the young (0.24 +/- 0.08 microgram/ml). HYD is produced in significant amounts during INH metabolism and this should not be neglected when evaluating INH related toxicity.

Acetylation↗

The disposition of antituberculous drugs in plasma of elderly patients. II. Isoniazid, rifampicin and pyrazinamide.

The pharmacokinetics of isoniazid (INH), rifampicin (RIF) and pyrazinamide (PZA) were studied in 18 elderly patients (67-89 years of age) and 19 young adult patients (19-59 years of age) on the first day and at one month of treatment for pulmonary tuberculosis. Elderly patients exhibited more side effects but there were no age-related changes in the pharmacokinetics of any of the three drugs when used in this combination. The clearance for INH and RIF at steady-state were significantly lower than after first-dose, while that of PZA remained unchanged. At steady-state the clearances for INH and RIF were not characteristic of polymorphic metabolism and auto-enzyme induction, respectively. Elderly patients are more sensitive to antituberculous (anti-TB) drugs; therefore, a modification in the dosage for this patient group should be considered.

Adult↗

The influence of hyperglycemia and diabetes mellitus on immediate and 3-month morbidity and mortality after acute stroke.

Fasting serum glucose, glycosylated hemoglobin, and fructosamine concentrations were determined in 304 consecutive subjects admitted with acute stroke, within 48 hours of ictus. Based on the medical history and these results, subjects were divided into known diabetics, newly diagnosed diabetics, subjects with stress hyperglycemia, and nondiabetics. The type of stroke was classified as lacunar infarct, cerebral infarct, or intracerebral hemorrhage, based on clinical examination by a neurologist and computed tomographic brain scan and/or autopsy. Immediate and 3-month outcomes were examined in relation to (1) fasting glucose, glycosylated hemoglobin, and fructosamine levels by stroke subtypes, and (2) glucose tolerance categories by stroke subtypes. A high fasting glucose level was associated with an increased mortality, but this was observed only among patients with intracerebral hemorrhage. Patients with stress hyperglycemia, but not diabetics, had increased mortality. In spite of having similar glucose concentrations to those patients with stress hyperglycemia, diabetics did not have a worse outcome compared with nondiabetics. It is concluded that the association between glucose concentration and outcome is a reflection of stress relating to stroke severity, rather than a direct harmful effect of glucose on damaged neurons.

Acute Disease↗

An echocardiographic assessment of asymptomatic elderly women with radiological cardiac enlargement.

To determine the significance of increased cardiothoracic ratio in elderly women without hypertension, symptoms or signs of cardiac disease, echocardiographic measurements from 22 elderly women (mean age 75.1 +/- 3.9 years) with increased cardiothoracic ratio (mean ratio 0.59 +/- 0.04), were compared with those from 21 women (mean age 75.3 +/- 5.6 years) with normal cardiothoracic ratio using M-mode, cross-sectional and Doppler echocardiography. Subjects with increased cardiothoracic ratio had greater left ventricular end diastolic dimension and volume, and greater right ventricular diastolic dimension (P less than 0.05). There was no difference in all other cardiac dimensions, nor in the ejection fraction and fractional shortening. Thirty-three to sixty-four percent of subjects in both groups had increased thickness of the septum and left ventricular posterior wall. Regurgitation at one or more valves on Doppler examination occurred in 91% of subjects with abnormal and 86% of subjects with normal cardiothoracic ratio. Compared to a group of 43 healthy young female subjects (mean age 27.9 +/- 6.3 years), elderly subjects had thicker interventricular septum and left ventricular posterior wall, increased left atrial and aortic root size, greater mitral valve A:E ratio, and higher frequency of valvular regurgitation detected by Doppler. The ejection fractions in elderly and young subjects, however, were similar. It is concluded that, in the majority of cases, increased cardiothoracic ratio in asymptomatic normotensive elderly women with normal physical examination and electrocardiogram is unlikely to represent cardiac pathology.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

A comparison of biochemical indices of bone turnover in elderly institutionalized and free-living subjects.

Plasma concentrations of calcium-phosphate, alkaline phosphatase, 25-hydroxyvitamin D (25(OH)D) and albumin, and fasting urinary sodium/creatinine (Na/Cr), calcium/creatinine (Ca/Cr) and hydroxyproline/creatinine (HPr/Cr) were measured in a survey of 208 Chinese elderly subjects living in chronic care institutions, and compared with values from free-living elderly subjects. Plasma parathyroid hormone estimations were also performed on a subpopulation of women living in an institution. Subjects in institutions had higher urinary HPr/Cr ratios in both men and women, as well as higher urinary Ca/Cr ratios in women, suggesting increased bone resorption. These values show significant variation depending on the degree of mobility. Factors which could contribute to the increased bone loss among institutionalized subjects are: reduced physical activity, reduced exposure to sunlight and hence reduced plasma 25(OH)D concentrations, low calcium intake, protein calorie malnutrition and possibly higher sodium intake. Correction of these factors may reduce the risk of fractures among the elderly living in chronic care institutions.

Activities of Daily Living↗

Intake and blood levels of some minerals in an elderly Chinese population.

Twenty-four hour intakes of potassium, calcium, and iron, and plasma concentration of potassium, copper and zinc were determined in a cluster sample of 400 apparently healthy subjects aged 60 years and over living in the community. Potassium and calcium intakes were lower in older men and lower in men compared to women. Both were much lower than intakes reported among Caucasian elderly, while iron intakes are comparable. Plasma potassium concentration was lower than values from studies of all ages and from studies of Caucasian elderly subjects. Copper and zinc concentrations were comparable to published values for adults of all ages. The significance of low potassium and calcium intake among elderly subjects in the population is discussed.

Journal Article↗