Effects of built environment on walking among Hong Kong older adults.

1. Reliable and valid interviewer-administered questionnaires were developed to investigate associations of perceived neighbourhood attributes of Hong Kong older adults with their walking for transportation and recreation. 2. Access to and availability of different types of services and destinations, provision of facilities for resting/sitting in the neighbourhood, and easy access to/from residential buildings may help maintain an active lifestyle by facilitating walking for transport in the neighbourhood. 3. Access to services, indoor places for walking, environmental aesthetics, low traffic, and absence of physical barriers may promote recreational walking..

Clinical vignettes in Parkinson's disease: a collection of unusual medication-induced hallucinations, delusions, and compulsive behaviours.

Hallucinations, delusions, and compulsive behaviors are frequent iatrogenic complications of the treatment of motor dysfunction in Parkinson's disease (PD). Although these have been studied, and the phenomenology described, there are few detailed descriptions of the various psychiatric problems our treated PD patients live with that allow physicians who do not have a great deal of experience with PD patients to appreciate the extent of their altered lives. This report is a compilation of vignettes describing these behavioral problems that the treating neurologist or psychiatrist attributed to the medications used for treating PD.

Excessive daytime sleepiness and on-road driving performance in patients with Parkinson's disease.

The impact of excessive daytime sleepiness (EDS) on road test performance was examined in patients with Parkinson's disease (PD). Twenty-one patients with PD completed the Epworth Sleepiness Scale (ESS) and an on-road driving test. Five participants had EDS according to their self-report on the ESS. Neither EDS nor PD medications were associated with on-road driving performance. These findings suggest that in this pilot study EDS did not impair PD patients' driving skills on a formal driving evaluation.

The association between prolyl hydroxylase metabolism and cell growth in cultured L-929 fibroblasts.

Prolyl 4-hydroxylase (EC 1.14.11.2) is a key enzyme in collagen biosynthesis, its active form is a tetramer (alpha 2 beta 2). In L-929 fibroblasts in the log phase of culture there is a low level of active enzyme. When the cell culture reaches confluency, prolyl hydroxylase activity in cells increases by a process that requires de novo RNA and protein synthesis. The same result may be achieved by crowding the cells (replating log phase cells at the density of stationary phase cells). In the work reported here we further examined induction of the enzyme. RNA synthesis necessary for enzyme induction is complete 6 h after "crowding" while protein synthesis requires 12 h. Thymidine (0.2-0.5 mM) added to log phase cells will also cause enzyme induction to the level found in "crowded" or resting cells. We also looked at the decay of the enzyme activity after subculture. This occurs rapidly (enzyme half-life is 1-2 h) and is concurrent with the re-entry of resting cells into cell cycle; however, thymidine added at the time of subculture to block DNA synthesis does not prevent the loss of prolyl hydroxylase activity. These results suggest that when cells are not engaged in propagation, they begin to synthesize luxury proteins such as prolyl hydroxylase. However, the loss of prolyl hydroxylase during subculture is probably not a direct consequence of DNA synthesis.

Dopamine overload visualized in the basal ganglia of rabbit brain during heatstroke can be suppressed by hypothermia.

The present study assesses the changes of dopamine levels in the basal ganglia (BG) of rabbit brain during heatstroke with or without hypothermia therapy. The dopamine levels were determined by using 6(F18) fluoro-L-dopa (FDOPA) positron emission tomography (PET) scan. Heatstroke was induced by exposing the anesthetized rabbits to a high blanket temperature (T(blanket)) of 45 degrees C. Hypothermia therapy was accomplished by decreasing T(blanket) from 45 to 16 degrees C. Regions-of-interest were carefully selected on the BG and cerebellum (C). The uptake ratio of FDOPA was defined as the mean counts per pixel from BG divided by the mean counts from C. BG/C ratios represent the dopamine levels of BG. The results showed that the values of mean arterial pressure (MAP) in heatstroke rabbits without hypothermia therapy were significantly lower than those in normothermic controls. However, BG/C FDOPA ratios were greater. Both the arterial hypotension and the increased BG/C FDOPA ratios observed during heatstroke were all reduced after hypothermia therapy. Our data demonstrate that the dopamine overload visualized in the BG of rabbit brain during heatstroke can be suppressed by hypothermia therapy.

Separation of low-level and high-level factors in complex tasks: visual search.

A method for assessing the role of low-level factors in complex tasks is described. The method, which involves comparing simple-discrimination performance and complex-task performance for the same stimuli, was used to assess the role of low-level factors in multiple-fixation visual search. In one experiment, the target and background were composed of line segments that differed in color, orientation, or both; in another, target and background were composed of filtered-noise textures that differed in spatial frequency, orientation, or both. Most of the variance in search time was found to be predictable from the discrimination data, suggesting that low-level factors often play a dominant role in limiting search performance. A signal-detection model is presented that demonstrates how current psychophysical models of visual discrimination might be generalized to obtain a theory that can predict search performance for a wide range of stimulus conditions.

Biosynthesis of procollagens and collagens by tissue explants and matrix-free cells from embryonic chick cornea.

Tendon and cornea of 17-day-old chick embryos primarily synthesize type I collagen as the major collagenous component nd type V collagen as a minor collagenous component. Matrix-free cells isolated from cornea and tendon synthesize and secrete mainly type I procollagen. A short lag period for the secretion of collagenous polypeptides into the medium of cell suspensions is observed. There is no significant difference in the synthesis and secretion of type I procollagen between matrix-free cells from tendon or cornea, except that cornea cells contain more free pro alpha 2(I) chains. The pro alpha 2(I) chain does not contain interchain disulfide linkages and can be separated from type I procollagen by ion exchange chromatography. However, no free pro alpha 2(I) chain can be detected in the medium of cell suspensions, suggesting that free pro alpha 2(I) is probably not secreted normally and may be rapidly degraded intracellularly. These results suggest that proper chain composition of type I procollagen is not regulated at the transcriptional or translational levels. Rather it is determined by the primary structure of the pro alpha chains and/or a posttranslational factor.

Factors associated with the use of publicly funded services by Hong Kong Chinese older adults.

This article analyzes cross-sectional data collected from a representative community sample of 2003 Chinese elderly people aged 60 or above in Hong Kong. We examined whether the use of publicly funded health services by older adults is equitable under the framework of Andersen model. A number of predisposing, enabling, and need factors were assessed as predictors of utilization in four categories of services including hospital admission, emergency room, general outpatient clinics, and specialist outpatient clinics. It was found that utilization of these four health services was consistently correlated with need factors. Specifically, self-rated health status and particular types of chronic illness were consistently and significantly related to utilization for all four of services in Hong Kong. On the other hand, age and family support were related to hospital admission whereas functional impairment was associated with the use of emergency room and general outpatient clinics. Findings suggest that publicly funded health services in Hong Kong are used equitably by elderly people.

Self-rated economic condition and the health of elderly persons in Hong Kong.

Studies have documented that health and income are important variables affecting the quality of life in old age. However, there is little knowledge about whether perceived financial sufficiency affects the health of elderly persons. Recent research has documented that in addition to material and behavioural determinants, psychosocial pathways also have an influence on health inequalities. This is the first paper to examine the relation between self-rated economic condition (measured with a single item question) and reported health conditions (i.e., somatic complaints, diagnosed physical diseases, functional health (Activities of Daily Living), self-rated health, and mental health status (General Health Questionnaire-30 [GHQ-30]) among elderly persons in Hong Kong. The respondents of the study were persons aged 65 and over residing in public housing estates in the Southern District of Hong Kong Island. Four hundred and fifty respondents were interviewed in 1995 by means of a structured questionnaire. The study found that although it did not record the actual income levels of the respondents, the subjective measure vividly demonstrated the health differentials among the elderly respondents. Multiple regression analyses suggested that self-rated economic condition was a significant predictor of the number of somatic complaints and physical illnesses reported, as well as of functional health, self-rated health, and mental health status (controlling for socio-demographic variables). However, the measure explained a higher proportion of variance in models related to psychological health than those related to physical health. The findings substantiated the role of psychosocial processes in understanding perceived health and illness and health inequalities in particular.

Diagnostic accuracy of [99mTc]TRODAT-1 SPECT imaging in early Parkinson's disease.

We evaluated the diagnostic accuracy of SPECT imaging using [(99m)Tc]TRODAT-1 (TRODAT), a relatively inexpensive technetium-labeled dopamine transporter ligand, in distinguishing 29 patients with early PD from 38 healthy volunteers. Mean TRODAT uptake values were significantly decreased in the caudate (p=0.0097) and anterior and posterior putamen (p < 0.0001) of PD patients compared to controls. Using the posterior putamen as the main region of interest resulted in the greatest accuracy (sensitivity 0.79, specificity 0.92). These findings show that TRODAT imaging can accurately differentiate early PD patients from controls and has the potential to improve the diagnosis of patients with early signs of PD.

Investigation of how different halos influence pin forces.

STUDY DESIGN: This study investigated the effect of the size and material of halo rings on the pin force produced at the halo pin-calvarium complex. SUMMARY OF BACKGROUND DATA: Loosening of halo pins has been a problem with using the halo-vest apparatus to stabilize cervical spine fractures. METHODS: One standard halo pin and seven different halo rings were used to test the anterior pin hole of each ring at a constant torque of 8 inch-pounds (0.9 Nm). RESULTS: Pin force fluctuated from halo to halo, and decreased as the nut was tightened. CONCLUSIONS: Identical torques applied to different halos will not guarantee the same magnitude of pin force for halo fixation.

Optimized protocols in terms of equalizing the true and accidental coincidences of each bed position in static multiple bed position carbon-11 PET studies and a target single bed position study.

Quantitative carbon-11 (11C) positron emission tomography (PET) is gaining more attention in oncological applications. In addition, it was discovered that accidental coincidences (randoms) can play an important role in studies such as partial volume effects correction without needing to use anatomical information. However, because of the short half-life of 11C, a homogeneous multiple bed position 11C image is hard to obtain. This study aimed to determine whether innovative pseudogating, optimized pseudogating and optimized double-up methods could match the true counts and randoms to each bed position and to a target single bed position study. A long cylindrical phantom filled with [11C]acetate was scanned by a dedicated PET scanner using six protocols: whole body, frame-duration-compensated whole body, double-up, optimized double-up, pseudogating, and optimized pseudogating. The differences between the protocols are in the initial activity, frame duration and frame number for each bed position. The parameters for pseudogating were determined according to the theory that true counts and randoms are proportional to the radioactivity and its square, respectively. The results show that the stated goals could only be achieved by pseudogating and optimized pseudogating. We conclude that pseudogating or optimized pseudogating must be applied for a critical quantitative study. However, optimized double-up and double-up methods are good alternatives for semi-quantitative and qualitative studies, respectively.

Dynamic evaluation of absorbed dose to the bladder wall with a balloon-bladder phantom during a study using [(18)F]fluorodeoxyglucose positron emission imaging.

An accurate evaluation of the absorbed dose to the bladder wall from 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG) is clinically important because the bladder is considered as a critical organ in most positron emission tomography (PET) studies that cumulate about 20% of the total activity injection during image procedures. In the MIRD calculation, no allowance is made for the inclusion of all the dynamic parameters that affect the actual dose to the bladder wall to be taken in the dose assessment. The goal of the study is to propose a dose evaluation model by using a dynamic bladder phantom and time-activity curves from the bladder PET imaging. The proposed model takes all dynamic parameters into account and provides a much more accurate dose estimation to the bladder. In this study, the lowest dose to the bladder wall was obtained at the conditions of having a larger initial volume for the bladder contents and a higher production rate for urine. It is then advised patients to drink a bulk amount of water before the FDG injection or after urine voiding to facilitate urine production and to enlarge the bladder surface area, which are the most crucial steps in reducing the dose to the bladder wall. In our study, the voiding schedule in dose calculation plays certain roles although it is much more critical in the conventional MIRD calculation. The model estimated that the lowest dose to the bladder would occur at an initial void about 40 min after the FDG injection and the urine voiding was as complete as possible.

Evaluation of the dose to the bladder wall using a dynamic balloon-bladder phantom and TLD measurements in 18F-FDG PET studies.

[18F]-2-deoxyglucose (18F-FDG) is one of the most useful radiopharmaceuticals in clinical positron emission tomographic imaging. Its final metabolic destination is the bladder, which accumulates the highest absorbed dose in the body during imaging. The aims of this study were to develop a dynamic bladder phantom to emulate the dynamic response of the bladder and to evaluate changes in the dose to the bladder wall during the imaging procedure. 18F-FDG of various concentrations can be drip-fed intravenously to the balloon-bladder at different uptake phases or extracted from the phantom during voiding. A dose evaluation model, introducing the concept of photon energy flux conversion into the dose calculation, is thus developed for clinical evaluation. The dose to the bladder wall using the proposed model is comparable to that measured using a thermoluminescence dosimeter (TLD), with a less than 5% discrepancy. The main advantages of the model are the use of the dose conversion factor, phi TLD, which is determined from real TLD measurements, and the ability to consider the dynamic characteristics of the bladder. To overcome the problems of diverse dose distributions among subjects, time-activity information provided by clinical bladder imaging is required, so that the method can be applied to other radiopharmaceuticals.

Attitudes towards mental patients in Hong Kong.

The purpose of this survey was to understand how the people of Hong Kong perceive mental health, mental illness, mental patients and mental health facilities. In March 1994, a total of 1,043 successful telephone interviews were conducted out of 2,202 valid telephone numbers. The sample was found to be representative of the Hong Kong adult population in terms of sex ratio, age structure, educational achievement and economic status. It was found that the majority of people of Hong Kong were very concerned about their mental health. Their knowledge on mental health was fairly good. Their attitudes towards mental patients and mental health facilities were, however, quite negative. Unlike previous western findings, these views towards mental patients and their rehabilitation facilities were found to be weakly associated with socio-economic factors including age, educational level and household income.

Effects of age, gender, and participation in volunteer activities on the altruistic behavior of Chinese adolescents.

Possible associations of gender, age, and participation in volunteer activities with altruistic behavior of Chinese adolescents were investigated. A representative sample of 1,105 Hong Kong Chinese adolescents (457 boys, 648 girls) were recruited from 20 schools. Results of multiple regression analyses indicated that there was a positive age effect on altruistic behavior. In addition, a positive association between self-reported altruistic behavior and frequency of participation in volunteer activities was found. No gender differences were found.

Intimacy and psychosocial adjustment in Hong Kong Chinese adolescents.

This study examined the association between 8 aspects of friend intimacy and 3 measures of psychosocial adjustment (self-esteem, deviant behavior, and purpose in life) among Hong Kong Chinese adolescents. The respondents were 289 students between 16 and 19 years of age from a cross-sectional study in Hong Kong. Bivariate correlation and multiple regression analyses revealed (a) friend intimacy was positively associated with self-esteem and purpose in life, and (b) friend intimacy was negatively correlated with deviant behavior. Results indicated that friend intimacy is an important variable that affects some aspects of psychosocial adjustment. Moreover, results of multiple regression analyses indicated that different measures of friend intimacy are related to deviant behavior and purpose in life. Therefore, it is crucial to study the relationship between different aspects of friend intimacy and different aspects of psychosocial adjustment among adolescents.

Emotional autonomy and depression among Chinese adolescents.

Depression is quite common among young people in Hong Kong Chinese society. This study examined the association between emotional autonomy and depressive symptomatology among Chinese young people in Hong Kong. The respondents were 512 young people between 16 and 18 years of age from a cross-sectional study in Hong Kong. Significant bivariate relationships were found between depressive symptomatology and three dimensions of emotional autonomy (individuation, nondependency on parents, and deidealization of parents). Using multiple regression models, the author found that depressive symptomatology was associated with two aspects of emotional autonomy: individuation and deidealization of parents. Results indicate that the relationships between depressive symptomatology and these three aspects of emotional autonomy are similar in both individualistic and collectivistic societies.

Social support and subjective well-being among Hong Kong Chinese young adults.

The associations between social support and 3 measures of subjective well-being--depressive symptomatology, negative affect, and positive affect--were studied among Hong Kong Chinese young adults (N = 475) between 16 and 19 years old. Significant bivariate relationships were found between positive affect and all dimensions of social support (including social network size, social contact frequency, satisfaction with social support, instrumental support, and helping others) except composition of social network. Helping others variables and relationship satisfaction variables were negatively related to both depressive symptoms and negative affect. Multiple regression models revealed that satisfaction with relationships with family members and friends was consistently associated with all measures of subjective well-being, and number of friends felt close to was positively related to positive affect.