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Biomedical subjects

J Woo

Publications and source records attributed to J Woo.

At least 199 records · Page 11Linked to original sources
PubMed1995

Outcomes of elderly stroke patients. Day hospital versus conventional medical management.

BACKGROUND AND PURPOSE: Much controversy exists over the value of geriatric day hospitals in the rehabilitation of elderly patients, and cerebrovascular accident is a particularly common diagnosis among patients referred to these day hospitals. We carried out a prospective, randomized study to compare the outcomes of elderly stroke patients managed by a geriatric team using a day hospital facility versus conventional medical management. METHODS: One hundred twenty elderly patients with acute stroke were randomized to inpatient care on a stroke ward under the care of either a neurologist or a geriatric team. Those under the care of neurologists were hospitalized until the attending physician felt that the patients had reached full rehabilitation potential. Patients under the care of the geriatric team were discharged home as soon as the team felt they were able to cope and given follow-up rehabilitation at the day hospital. Family or community support was arranged when necessary for both treatment groups. On recruitment, patient demographics, medical history, clinical features related to stroke, and functional ability as measured by the Barthel Index were noted. Subjects were reviewed at 3 and 6 months to assess functional level, hospital and outpatient services received, general well-being, mood, and level of satisfaction. Costs of treatment of the two groups were also compared. RESULTS: Functional improvement (Barthel Index score) was greater in the group managed by the geriatricians with a day hospital facility compared with the conventional group at 3 months (P = .03). There were also fewer outpatient visits among the day hospital patients at 6 months (P = .03). No significant difference was found in costs between the two treatment groups. CONCLUSIONS: Compared with conventional medical management, care in the geriatric day hospital hastened functional recovery and reduced outpatient visits in elderly stroke patients without additional cost.

Activities of Daily Living↗
PubMed1995

Respiratory symptoms in elderly Chinese living in Hong Kong.

Respiratory diseases can cause considerable disability in the elderly because of their limited respiratory reserve as a result of ageing. We have investigated the prevalence of respiratory symptoms and diseases in elderly Chinese in Hong Kong and compared these data with those in elderly Caucasian populations. Two thousand and thirty two (999 male and 1,033 female) subjects, selected by age-stratified random sampling from a register of Hong Kong residents aged 70 yrs and over were interviewed to complete a respiratory questionnaire. Total serum immunoglobulin E (IgE) was measured in 195 subjects. At least one respiratory symptom was reported by 56% of subjects. The most frequently reported symptoms were morning phlegm (26%), chronic cough with phlegm (10%) and wheeze in the past 12 months (8%). Of the self-reported diseases, the commonest was chronic bronchitis (7%), followed by asthma (5%), pulmonary tuberculosis (3%) and emphysema (2%). Of the 218 subjects with obstructive airway diseases, 128 (59%) had sought medical advice in the past 12 months. The most important determinants for respiratory symptoms and diseases were smoking and social class. Total serum IgE was significantly higher in current smokers than nonsmokers and also in those with chronic cough and phlegm than those without these complaints. Our study shows that respiratory ailments in Hong Kong elderly are as common as those reported in Sweden and the USA but less than those in England.

Aged↗
PubMed1995

Combined pyridostigmine-thyrotrophin-releasing hormone test for the evaluation of hypothalamic somatostatinergic activity in healthy normal men.

Pyridostigmine (PST), a cholinesterase inhibitor, induces a clear growth hormone (GH) release in man by suppression of hypothalamic somatostatin (SRIH). Somatostatin suppresses thyrotrophin (TSH) release in rats and men. Earlier studies showed that the thryotrophin-releasing hormone (TRH)-induced TSH response was not altered by 60-120 mg of PST. We studied whether a larger dose (180 mg) of PST can increase the TSH response to TRH. Six healthy young men were studied with the following six tests: (Test 1) 200 micrograms of TRH i.v.; (Test 2) 180 mg of PST po; (Test 3) three different doses of PST (60, 120, 180 mg) + TRH; (Test 4) 100 micrograms of octreotide (SMS) i.v.; (Test 5) SMS + TRH; (Test 6) PST + SMS + TRH. A large dose of PST (180 mg) significantly augmented GH, TSH and prolactin responses to TRH, while smaller doses of PST (60 and 120 mg) did not significantly increase the responses of GH and TSH. While the increased TRH-induced prolactin response by PST was not suppressed by SMS, the increased responses of GH and TSH were suppressed remarkably by SMS. Most of the subjects noticed a mild to moderate abdominal pain, nausea and muscular fasciculation after the administration of a large dose of PST administration. These data suggest that suppression of hypothalamic SRIH secretion by 180 mg of PST can augment the TSH response to TRH. However, the considerable side effects should be minimized before clinical application of the combined PST-TRH test.

Adult↗
PubMed1995

Adverse drug reactions and outcome of elderly patients on antituberculosis chemotherapy with and without rifampicin.

Antituberculosis (anti-TB) chemotherapy with concomitant administration of rifampicin and isoniazid may cause a higher incidence of hepatotoxicity than isoniazid alone. We carried out a prospective study of the adverse reactions to anti-TB drugs and the clinical outcome in elderly patients on anti-TB chemotherapy, to find out whether the omission of rifampicin from standard anti-TB regime would result in a reduction of adverse reactions and/or mortality during anti-TB treatment. Eighty elderly patients (age > 65 years) with TB were recruited into the study. They were randomised to receive anti-TB chemotherapy consisting of isoniazid, pyrazinamide and ethambutol with or without rifampicin for six months. Adverse reactions and mortality occurring during treatment were noted. A significantly higher number of patients on rifampicin had elevated liver enzymes compared with those not receiving rifampicin. All of these reactions responded favorably to adjustment of anti-TB drugs. There was no significant difference between the two groups in the incidence of symptomatic adverse reactions or mortality during treatment. However, five patients not given rifampicin had unsatisfactory resolution radiographically and required additional therapy. We conclude that the inclusion of rifampicin in the anti-TB regime offers a better therapeutic response but without significantly affecting the incidence of adverse reactions or mortality during treatment in elderly patients with TB.

Aged↗
PubMed1995

Correlation between steady-state plasma concentration of antituberculous drugs and age, inclusion of rifampicin in the treatment regimen, adverse drug reactions and other clinical parameters.

A regional hospital in Hong Kong examined the correlation between plasma concentrations of rifampicin, pyrazinamide, isoniazid and its metabolite hydrazine and age, inclusion of rifampicin in the treatment regimen, adverse drug reactions and other clinical parameters. One hundred eighty subjects with tuberculosis were admitted consecutively to the medical wards of the Prince of Wales Hospital over a one and a half year period. Elderly patients > 65 years were randomized into one of two treatments with and without rifampicin in addition to isoniazid, pyrazinamide and ethambutol; younger patients received all four drugs. Plasma antituberculous drug concentrations were determined using high performance liquid chromatography. Elderly patients taking rifampicin had a higher mean steady-state concentration of isoniazid, together with a higher incidence of adverse effects compared with those not taking rifampicin. No age related differences were observed for the other drugs. For the whole group, higher mean concentrations of hydrazine, rifampicin and pyrazinamide were associated with a higher incidence of adverse effects and the presence of coexisting diseases. It is concluded that in sick elderly patients with coexisting diseases, use of rifampicin in the antituberculous regimen should be accompanied by close monitoring for side effects, and that there may be an indication for use of lower dosages of antituberculous drugs in such patients.

Adult↗
PubMed1994

Mutations affecting the activity of toxic shock syndrome toxin-1.

Toxic shock syndrome toxin-1 (TSST-1), the potent staphylococcal exoprotein linked to most cases of the toxic shock syndrome, is a V beta-restricted T-cell mitogen (a so-called "superantigen"). TSST-ovine (TSST-O) is a natural variant of TSST-1, and is produced by certain ovine mastitis-associated strains of Staphylococcus aureus. Compared to TSST-1, TSST-O is only weakly mitogenic for leporine or murine splenocytes. It differs from TSST-1 at 7 amino acid residues over its 194 amino acid length. Terminus shuffling between the two proteins has suggested that their C-terminal differences (T69, Y80, E132, and I140 in TSST-1; 169, W80, K132, and T140 in TSST-O) are in part responsible for their discrepant mitogenic properties. In order to explore further the functional consequences of altering TSST-1 at residues 132 and 140, we engineered point mutants of TSST-1 at those positions. The mutant proteins were purified to homogeneity from culture supernants of a nontoxigenic strain of S. aureus using a combination of ultrafiltration, liquid-phase isoelectric focusing, and ion-exchange chromatography. The mutants retained global structural integrity as evidenced by circular dichroism spectroscopy, their preserved resistance to trypsin digestion, and their preserved binding to a neutralizing murine monoclonal antibody. The mutants were then tested for mitogenicity for human T-cells: The mutant I140T was approximately as active as wild-type TSST-1, while the mutant E132D was about 10-fold attenuated. On the other hand, the mutants E132A or E132K were each at least 1000-fold attenuated.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Toxins↗
PubMed1994

Isolation, phenotype, and allostimulatory activity of mouse liver dendritic cells.

Donor liver-derived dendritic cells (DC) have recently been identified within various lymphoid and nonlymphoid tissues of organ allograft recipients, including nonimmunosuppressed mice transplanted with and permanently accepting major histocompatibility complex (MHC)-disparate hepatic allografts. These findings have raised questions about the basis of the tolerogenicity of the liver--and, in particular, about the properties of liver-derived DC. To study further the structure, immunophenotype and allostimulatory activity of leukocytes resident in normal mouse (B10.BR;H-2k, I-Ek) liver, a procedure was developed to maximize the yield of viable, nonparenchymal cells (NPC) obtained following collagenase digestion of perfused liver fragments and density centrifugation (Percoll). These cells comprised populations expressing lymphoid and myeloid cell surface antigens. As compared with spleen cells, they proved good allostimulators of naive (B10; H-2b, I-E-) splenic T cells when tested in primary mixed leukocyte reactions (MLR). After overnight (18-hr) incubation of the NPC, enrichment for transiently adherent, low-density (LD) cells on metrizamide gradients permitted the recovery of low numbers of cells (approx. 2-5 x 10(5) per liver), many of which displayed distinct DC morphology. Flow cytometric analysis revealed that these cells were CD3-, CD4-, CD8-, and B220-, but strongly expressed CD45 (leukocyte-common antigen), and mild-to-moderate levels of CD11b, heat-stable antigen, and CD44. The cells also expressed moderate intensity of NLDC 145 but not 33D1, DC restricted markers which have been shown to be differentially expressed on mouse DC isolated from various organs. This DC-enriched population was more strongly MHC class II(I-Ek)+ than NPC, as determined by immunocytochemistry and flow cytometry and exhibited much more potent allostimulatory activity for naive T cells. These findings demonstrate that freshly isolated murine liver NPC, and perhaps their counterparts in situ, exhibit allostimulatory activity that is enhanced in the non-adherent, low-density (DC-enriched) fraction after overnight culture. They further suggest that the maturation of liver DC may play a key role in determining the immunogenicity and or tolerogenicity of hepatic allografts.

Animals↗
PubMed1994

Propagation of dendritic cell progenitors from normal mouse liver using granulocyte/macrophage colony-stimulating factor and their maturational development in the presence of type-1 collagen.

Within 1 wk of liquid culture in granulocyte/macrophage colony-stimulating factor (GM-CSF), normal B10 BR (H-2k I-E+) mouse liver nonparenchymal cells (NPC) formed loosely adherent myeloid cell clusters that have been shown to contain dendritic cell (DC) progenitors in similar studies of mouse blood or bone marrow. Mononuclear cell progeny released from these clusters at and beyond 4 d exhibited distinct dendritic morphology and were actively phagocytic. After 6-10 d of culture, these cells strongly expressed CD45, CD11b, heat stable antigen, and CD44. However, the intensity of expression of the DC-restricted markers NLDC 145, 33D1, and N418, and the macrophage marker F4/80, intercellular adhesion molecule 1, and Fc gamma RII was low to moderate, whereas the cells were negative for CD3, CD45RA, and NK1.1. Splenocytes prepared in the same way also had a similar range and intensity of expression of these immunophenotypic markers. Unlike the splenic DC, however, most of the GM-CSF-propagated putative liver DC harvested at 6-10 d expressed only a low level of major histocompatibility complex (MHC) class II (I-Ek), and they failed to induce primary allogeneic responses in naive T cells, even when propagated additionally in GM-CSF and tumor necrosis alpha and/or interferon gamma-supplemented medium. However, when 7-d cultured GM-CSF-stimulated liver cells were maintained additionally for three or more days on type-1 collagen-coated plates in the continued presence of GM-CSF, they exhibited characteristics of mature DC: MHC class II expression was markedly upregulated, mixed leukocyte reaction stimulatory activity was increased, and phagocytic function was decreased. Similar observations were made when Ia+ cells were depleted from the GM-CSF-propagated cells before exposure to collagen. Further evidence that the GM-CSF-stimulated class IIdim or class II-depleted hepatic NPC were immature DC was obtained by injecting them into allogeneic B10 (H-2b I-E-) recipients. They "homed" to T cell-dependent areas of lymph nodes and spleen where they strongly expressed donor MHC class II antigen 1-5 d later. These observations provide insight into the regulation of DC maturation, and are congruent with the possibility that the migration of immature DC from normal liver and perhaps other organ allografts may help explain their inherent tolerogenicity.

Animals↗
PubMed1994

Effect of age and disease on two drug binding proteins: albumin and alpha-1- acid glycoprotein.

The influence of age and disease on serum albumin and alpha-1-acid glycoprotein was studied in 126 subjects (69 M, 57 F) presenting with tuberculosis and after recovery. Albumin concentration fell with age in both disease and healthy states, and alpha-1-acid glycoprotein concentration rose with age in the healthy state. Age-related differences were less marked in the disease state. During recovery from illness, serum albumin concentration rose and alpha-1-acid glycoprotein concentration fell. The mean concentration difference in the latter was lower in the older age groups. The clinical consequences of changes in binding protein concentrations as a result of ageing and disease need to be studied further for individual drugs.

Adult↗
PubMed1994

Functional brain MR imaging based on bolus tracking with a fast T2*-sensitized gradient-echo method.

Dynamic physiological scanning, based on temporary changes in local field homogeneity during the passage of a contrast agent bolus, has been performed hitherto with echo-planar imaging (EPI) or conventional gradient-recalled techniques (FLASH). Here, it is shown that the T2* sensitivity of conventional FLASH techniques can be improved drastically on a conventional whole body instrument by delaying the gradient-echo until the subsequent TR-period without increasing total imaging time. Examples are given for a full k-space matrix (128 x 256) obtained within 2 s with a TE of 25 ms, resulting in images free of artifacts. The method is applied to bolus tracking through the brain of healthy volunteers during visual stimulation and in the dark. An average increase of regional cerebral blood volume (rCBV) in the visual cortex of 10.9% (n = 9, p = .001) was found.

Blood Volume↗
PubMed1994

FK506 inhibits the differentiation of developing thymocytes but not negative selection of T cell receptor V beta 5+ and V beta 11+ T lymphocytes in vivo.

To examine the influence of FK506 on lymphocyte development, we employed a syngeneic bone marrow transplantation model using MHC-disparate B10 (H-2b, I-Ab) and B10.BR (H-2k, I-Ak, I-Ek) mice. B10 mice, which do not express class II I-E, do not delete any known T cell receptor (TCR)-V beta, while B10.BR mice (MHC class II I-Ek, I-Ak) delete V beta 5+ and V beta 11+ TCR. Continuous daily treatment of syngeneically reconstituted B10 mice with FK506 delayed the development of thymocytes from the CD4+CD8+ to CD4+CD8- stage, while no effect was observed at the earlier CD4-CD8- to CD4+CD8+ stage. At the same time, there was a significant reduction in TCRhigh thymocytes compared with untreated, syngeneically reconstituted controls. These results suggest that FK506 treatment interfered with thymic positive selection. We also examined whether FK506 treatment would influence negative selection. Levels of expression of V beta 5+ and V beta 11+ T cells in FK506-treated B10.BR-->B10.BR recipients were similar to those observed in unmanipulated, syngeneically reconstituted B10.BR-->B10.BR controls. This was not due to the inhibition of clonal proliferation by FK506, since 35 days after drug withdrawal complete recovery of the peripheral Thy1.2+ population was observed, while the percentages of V beta 5+ and V beta 11+Thy1.2+ T cells were maintained at values similar to controls. Surprisingly, clonal proliferation stimulated by monoclonal antibody against V beta 5 and V beta 11 TCRs was observed in CsA-treated, syngeneically reconstituted B10.BR mice but not in FK506-treated mice, suggesting that CsA may be more likely to induce autoreactivity. Differences in thymic architecture between FK506- and CsA-treated animals further suggested that the drugs may differ in their effects on T cell development in vivo.

Animals↗
PubMed1994

Risk factors for acute myocardial infarction in a southern Chinese population.

Although the mortality rate from coronary artery disease in Hong Kong is only one-fourth of that of northern Europe and the United States, the disease has been and remains the second major cause of death (after all cancers combined). Beginning in 1987, we have conducted a case-control study of acute myocardial infarction in four Hong Kong hospitals. This study, one of the biggest case-control studies conducted in the Chinese population of both men and women, confirms the importance of several risk factors--cigarette smoking, history of hypertension, history of diabetes, body fatness, and lack of physical activity--previously described in data collected in western populations. In addition, more adverse childhood experience was also found to be an important risk factor of acute myocardial infarction. Further research in appropriate intervention measures in education in the prevention and cessation of smoking, the control of blood pressure, diabetes, and overweight, and adequate exercise could significantly help reduce the risk of acute myocardial infarction in the Hong Kong Chinese population.

Aged↗
PubMed1994

Nutritional status of elderly patients during recovery from chest infection and the role of nutritional supplementation assessed by a prospective randomized single-blind trial.

We examined changes in the nutritional status of elderly patients with chest infection for a period of 3 months after discharge from hospital, including the effects of nutritional supplementation on well-being and functional status as well as on nutritional indices. Eighty-one subjects admitted to an acute medical ward aged 65 years and over with chest infection were recruited consecutively, and randomized to receive supplement (500 ml of Ensure liquid daily) for 1 month, or no supplement, on discharge. Assessment at baseline, 1, 2 and 3 months included a questionnaire to determine health, mental and functional status, and anthropometric measurements. Biochemical nutritional status was assessed at baseline, 1 and 3 months, and dietary intake (24 h recall method) at 1 and 3 months. During recovery, both supplement and non-supplement groups showed improvement in various measures of well-being and biochemical status. In addition, the former group showed improvement in more anthropometric measurements, in thiamine and pyridoxine status, while the non-supplement group showed a lower level of functional ability after 3 months. Various measures of well-being and biochemical status of the water-soluble vitamins were better in the supplement groups. We conclude that nutritional supplementation may have a role in helping elderly patients to recover from chest infections.

Aged↗
PubMed1994

Sustained-release isradipine compared with spirapril in the treatment of elderly patients with isolated systolic hypertension.

The benefits of treating isolated systolic hypertension (ISH) have been established, but the most appropriate choice of drug is still uncertain. For this reason, a sustained-release formulation of isradipine was compared with spirapril in a double-blind randomized study in elderly Chinese patients with ISH. The dosage was titrated if necessary after 4 weeks of treatment. The reduction in systolic/diastolic blood pressure after 8 weeks was similar for both treatments--20/10 mm Hg with isradipine versus 24/6 mm Hg with spirapril--measured in the supine position. There were no orthostatic symptoms and both treatments were well tolerated.

Aged↗
PubMed1994

Association between calcium regulatory hormones and other factors and bone mineral density in elderly Chinese men and women.

BACKGROUND: The purpose of the study was to determine if bone mineral density (BMD) in elderly Chinese subjects was associated with indices of calcium metabolism (parathyroid hormone, vitamin D), osteocalcin, and other nonbiochemical factors. METHOD: 104 men (mean age 74 +/- 6 yrs) and 213 women (mean age 76 +/- 8 yrs) with no previous history of fractures were recruited from old age hostels and community centers. BMD was measured with dual energy X-ray absorptiometry. RESULTS: BMD in both sexes was associated with body mass index (BMI), arm circumference, and skinfold thicknesses. Additionally, in women there was a positive association with grip strength and load-bearing activities, a negative association with age in all sites except for the lumbar spine, and negative associations with indices of bone turnover (osteocalcin, urinary hydroxyproline/creatinine and calcium/creatinine ratios). After adjusting for BMI, women with hypertension or taking antihypertensive drugs had higher mean BMD at the lumbar spine. Multivariate analyses showed that only BMI predicted BMD in men, while age, BMI, and arm circumference were predictors of BMD in women. CONCLUSION: Indices of calcium metabolism were not correlated with BMD in this elderly Chinese population, suggesting that the age-related rise in parathyroid hormone and reduced intestinal absorption of calcium may not be important factors in determining BMD in elderly Chinese men and women.

25-Hydroxyvitamin D 2↗