Biomedical subjects

W T Hung

Publications and source records attributed to W T Hung.

At least 19 recordsLinked to original sources

PubMed2006

Association between setting quantified road safety targets and road fatality reduction.

Since the 1980s, many countries have set quantified road safety targets as part of their comprehensive road safety strategies. This paper studies the association between the setting of quantified road safety targets and road fatality reduction over the past two decades. Both aggregate and disaggregate levels of hypothesis tests are performed on data from 14 countries that set road safety targets during the period 1981-1999. A before-and-after analysis of the treatment and comparison groups is conducted, and the results show that the majority of countries with quantified road safety targets experienced a reduction in road fatalities in this period. Overall, the establishment of quantified road safety targets is found to have an appreciable association with an improvement in road safety.

Accidents, Traffic↗

PubMed2006

Application of the mixed venous blood concentration equation in desflurane anesthesia.

BACKGROUND: We have previously proposed an equation derived from Fick's law and Lin's concept of effective blood concentration (EBC) to calculate the mixed venous blood concentration (MVBC) of isoflurane. Desflurane has a lower blood/air partition coefficient than isoflurane and, as such, promotes a faster induction and recovery from anesthesia. In this study, we investigated the application of the MVBC equation to predict the MVBC of desflurane. METHODS: We maintained anesthesia with a fixed inspired concentration (CI) of desflurane (10%) during cardiac anesthesia in 11 patients. In order to measure the real concentrations of desflurane in mixed venous blood, pulmonary arterial blood samples were collected at different time points via a Swan-Ganz catheter for gas chromatographic-mass spectrometric determination. The relationship between the calculated concentrations and the actual blood sample concentrations of desflurane in mixed venous blood was investigated. Lin's EBC method was also used and the results were compared with those of MVBC. RESULTS: The calculations from our derived MVBC equation and the actual blood concentrations showed a similar kinetic pattern; the concentration levels were approximately the same and correlated well (r = 0.89) during anesthesia. However, the EBC method failed to accurately estimate the actual blood concentrations. CONCLUSIONS: The results demonstrate that our equation, but not the EBC method, may be useful for estimating pulmonary blood concentrations of desflurane. The clinical significance and the importance of the method merit further investigation.

Aged↗

PubMed2006

Identifying the determinants of 1-year post-stroke outcomes in elderly patients.

OBJECTIVES: To examine 12-month outcomes and develop predictive models for outcomes in elderly stroke patients. METHODS: Prospective study of 186 consecutive acute stroke patients aged > or = 65 years admitted to a local hospital between March 2002 and March 2003. Outcome measurements included mortality, functional independence measure (FIM) score and nursing home placement. Two predictive models, using multiple logistic regression analysis, were developed to identify the factors associated with (i) mortality, and (ii) being alive and independent (defined as mean FIM score > or = 90) at 12 months. RESULTS: One hundred and seventy two (92%) patients were followed up at 12 months post-stroke. Mortality rate was 31%, and was significantly higher in nursing home vs non-nursing home origin patients (68% [15/22] vs 25% [38/150]). Nursing home placement for non-nursing home origin survivors was 28% (31/112). Age > or = 85 years was associated with higher mortality (odds ratio = 5.3, 95% confidence interval = 1.8-15, P < 0.01) and lower FIM for patients living at home pre-stroke. Predictive models showed that age, not living at home pre-stroke, pre-stroke FIM < 108, inability to walk on admission, dysphasia, visual field loss and haemorrhagic stroke were associated with worse outcome. CONCLUSIONS: Predictive models--by developing new strategies to improve outcomes through identifying treatable predictive factors--may be clinically useful in elderly stroke patients.

Activities of Daily Living↗

PubMed2005

Would relaxing speed limits aggravate safety? A case study of Hong Kong.

This paper studies the effect of the changed speed limits on accident counts for major roadways in the urban environment of Hong Kong. In 1999-2002, the speed limits of a number of sections of roadway were reviewed and increased. Nineteen of them were major roadways. Their speed limits were raised by 10-20 km/h from 50 to 70 km/h. Before and after studies were carried out to investigate the changes in accident counts with respect to the set of carefully chosen comparison groups. Qualification tests for these comparison groups were conducted to confirm their suitability for the studies. In the majority of the treatment sites, the accident counts were worse after the increase in speed limits, both for the category of fatal, serious and slight (FSS) accidents, and for the category of fatal and serious (FS) accidents. Overall, the relaxation of the speed limit from 50 to 70 km/h increased the FSS accident counts by 15% and the FS accident counts by 1%. The relaxation of the speed limit from 70 to 80 km/h increased the FSS accident counts by 18% and the FS accident counts by 36%.

Accidents, Traffic↗

PubMed2005

Application of MVBC equation to predict mixed venous blood concentrations of sevoflurane in cardiac anaesthesia.

We have proposed an equation for estimating the real-time mixed venous blood concentration (MVBC) of isoflurane in cardiac anaesthesia. However, information related to the application of our method to sevoflurane is lacking. We studied 12 patients undergoing cardiac surgery and anaesthetised with sevoflurane. At different time points, pulmonary arterial blood samples were collected for gas chromatography-mass spectrometry (GC-MS) to determine the real mixed venous concentrations of sevoflurane. The inspired and expired concentrations of sevoflurane, measured by a gas monitor, were used for the MVBC calculations. Using Bland-Altman analyses, we found that the calculated MVBCs accurately represent the actual concentrations of sevoflurane in pulmonary arterial blood, as shown by a near-zero percentage bias with a 0.14% precision between the two concentrations. The results demonstrated that our equation could be a useful method for estimating the pulmonary blood concentration of sevoflurane.

Aged↗

PubMed2005

Prevalence of Parkinson's disease in Sydney.

OBJECTIVE: To examine the prevalence of Parkinson's disease (PD) in Bankstown, Sydney, using the same methodology as a previous study in Randwick, Sydney, Australia (1998-1999). PARTICIPANTS AND METHODS: Twenty census districts (CDs) for the Bankstown local government area were randomly selected. Research personnel door-knocked every household within the CDs to locate people aged > or =55 years. A structured questionnaire (containing four screening questions for PD) was administered to those agreeing to participate. Screened positive participants were invited to come for a clinical examination. This is a continuation of the previous study and data have been combined. RESULTS: Combining data for Bankstown and Randwick gave 1028 participants; crude prevalence, 780 per 100,000 (CI: 546-1077). In Bankstown, there were 501 participants aged > or =55 years (response rate 70%); 135 were screened positive with 101 (74.8%) agreeing to a clinical examination. The prevalence of PD in the Bankstown community was 3.4% (17 of 501) (95% CI: 1.98-5.43) for those aged > or =55 years; crude prevalence 776 per 100,000 (CI: 452-1241). CONCLUSION: The combined results of two Sydney studies appear to indicate that Sydney has one of the highest prevalence estimates of PD in developed countries.

Aged↗

PubMed2004

A qualitative assessment methodology for road safety policy strategies.

This paper proposes a qualitative assessment methodology that is comprised of a cluster analysis and an autoregression analysis that assess the effects of various road safety strategies implemented in Hong Kong over the last 10 years. The cluster analysis is first used to group over a hundred road safety projects and programs into a smaller set of meaningful road safety policy strategy clusters. These strategies, together with the trend factor, seasonal pattern, car crashworthiness and meteorological data are then used in the autoregression analysis to relate to the fatality and casualty rates of drivers, passengers, motorcyclists, and pedestrians. This method allows the evaluation of the overall effects of the road safety strategies, and the effects and relative significance of each individual strategy. The evaluation method is described, and the main findings of the study are discussed.

Accident Prevention↗

PubMed2003

Strong association between N-acetyltransferase 2 genotype and PD in Hong Kong Chinese.

BACKGROUND: The slow acetylator genotype for N-acetyltransferase 2 (NAT2 genotype) may be associated with PD in white subjects and the genotype is common in both white and Chinese populations. Whether there is a relationship between NAT2 genotype and PD in Chinese subjects is not known. OBJECTIVE: To investigate the association between the slow acetylator genotype for N-acetyltransferase 2 and PD in a Chinese population. METHODS: The authors obtained DNA samples and documented sex, age, and smoking history in 99 Chinese patients with PD and in 126 control subjects from two major Hong Kong hospitals. PCR-restriction fragment length polymorphism was used to identify M1, M2, and M3 mutant polymorphisms of the slow acetylator genotype for N-acetyltransferase 2. Logistic regression analyses were carried out to investigate the relationships between the different variables and PD. RESULTS: The frequency of the slow acetylator genotype for N-acetyltransferase 2 in the PD group was significantly higher than that of the control group (68.7% vs 28.6%) with an OR of 5.53 (95% CI 3.08 to 9.92) after adjusting for age, sex, and smoking history. In a subgroup analysis smoking had no modifying effect on the association between genotype and PD. CONCLUSIONS: There is a significant association between PD and the slow acetylator genotype for N-acetyltransferase 2 in Hong Kong Chinese. The OR found is among the highest reported so far in all susceptibility gene studies for PD in both Chinese and white subjects and provides evidence for a possible functional relationship between NAT2 slow acetylator genotype and PD in both racial groups.

Acetylation↗

PubMed2003

Diagnostic abilities of three CAD methods for assessing microcalcifications in mammograms and an aspect of equivocal cases decisions by radiologists.

Radiologists use an "Overall impression" rating to assess a suspicious region on a mammogram. The value ranges from 1 to 5. They will definitely send a patient for biopsy if the rating is 4 or 5. They will send the patient for core biopsy when a rating of 3 (indeterminate) is given. We have developed three methods to aid diagnosis of cases with microcalcifications. The first two methods, namely, Bayesian and multiple logistic regression (with a special "cutting score" technique), utilise six parameter ratings which minimise subjectivity in characterising the microcalcifications. The third method uses three parameters (age of patient, uniformity of size of microcalcification and their distribution) in a multiple stepwise regression. For both training set and test set, all three methods are as good as the two radiologists in terms of percentages of correct classification. Therefore, all three proposed methods potentially can be used as second readers.

Algorithms↗

PubMed2003

Genetic and environmental risk factors and their interactions for Parkinson's disease in a Chinese population.

The interaction between genetic and environmental factors for PD was examined in a Chinese population. It was found that although the intron 2 MAOB (GT)(n) repeat polymorphism was not associated with PD in the population, a relationship might have been masked by the "protective effect" of tea drinking. In individuals who did not drink tea (<1 cup/day), the possession of short length < or = 178 bp (GT)(n) alleles conferred a borderline significant increased risk for PD (adjusted OR=1.47; C.I.=1.03-2.1). As the extent of tea consumption increased, the association between the < or = 178 bp allele and PD disappeared. This result suggests that the MAOB gene may be associated with PD in Chinese if the putative protective effect of tea drinking is taken into account. The significance of this finding is unclear as the study may be limited because of its marginal significance and limited numbers. However, it does demonstrate the importance of considering putative positive and negative environmental risk factors in any examination of genetic risk factors for PD.

Asian People↗

PubMed2003

Treatment of recurrent aspiration pneumonia in end-stage dementia: preferences and choices of a group of elderly nursing home residents.

BACKGROUND: Clinicians are often faced with the dilemma of how best to manage patients with advanced dementia who present to the hospital with repeated episodes of aspiration pneumonia. Rarely, if at all, are the opinions of the group that is most likely to be directly affected, that is the older nursing home resident, sought. This study seeks to fill that gap. AIMS: To study the choices and preferences of a group of elderly nursing home residents in the treatment of recurrent aspiration pneumonia on a background of severe disability from end-stage dementia. METHODS: A descriptive cross-sectional interview study using a hypothetical scenario carried out in six nursing homes within eastern Sydney, from June to August 2000. Views and attitudes towards hospitalization, antibiotic use, tube feeding and other treatment measures, given a situation of recurrent aspiration pneumonia and end-stage dementia, were obtained. RESULTS: Fifty-two elderly nursing home residents who were cognitively intact and not depressed were interviewed. Most of the subjects would prefer further hospital admissions (61.5%, P<0.1) and would choose to have antibiotic treatment (73.1%, P<0.001). Slightly more than half would not agree to artificial ventilation. Sixty-nine percent of the respondents would not agree to feeding via a nasogastric tube (P<0.05) and 71% would not agree to a feeding gastrostomy (P<0.001). Most would agree to a modified diet (75%, P<0.0001) and to continue oral feeding despite the attendant risk of re-aspiration (59.6%, P<0.01). CONCLUSIONS: The participants generally preferred to be treated in a hospital setting given the scenario. Most disagreed with the use of artificial feeding.

Aged↗

PubMed2002

Lack of association between CYP1A1 polymorphism and Parkinson's disease in a Chinese population.

Apart from very few families who have a direct cause from genetic mutation, causes of most Parkinson's disease (PD) remain unclear. Many allelic association studies on polymorphism of different candidate genes have been studied. Although these association studies do not imply a causal relationship, it does warrant further studies to elucidate the pathophysiologic significance. CYP1A1 polymorphisms have been reported to be associated with PD in a Japanese population sample. Since CYP1A1 transforms aromatic hydrocarbons into products that may be neurotoxic and perhaps lead to PD, we therefore undertook a study to look at the possible association of CYP1A1 polymorphism and PD in a Chinese population. Contrary to the Japanese result, we did not find any statistically significant difference between the PD group and the control group in our study with a bigger sample size.

Aged↗

PubMed2001

Pilot study of prevalence of Parkinson's disease in Australia.

Parkinson's disease is a common neurological disease and its prevalence increases with age. Because of an ageing population and changing environment compared to the last epidemiological study done in Australia over 30 years ago, we have conducted a door-to-door pilot survey which looked at the latest prevalence as well as putative risk factors in a random population. We used a two-phase investigation method (screening followed by detailed examination) in a random community sample of 2,820 households (with 527 individuals aged 55 and over) along with 203 residents in aged care facilities (single-phase examination for residents aged 55 and above) in the Randwick area of Sydney, New South Wales. We had a 75% participation rate in the community and a 94% in the aged care facilities. The results of the survey in this sample of 730 subjects indicated that the crude prevalence of Parkinson's disease was between 3.6 and 4.9% (higher in the aged care facilities). The putative risk factors positively identified using chi-square method were 'family history' (p < 0.01) and 'exposure to chemicals at work or in surrounding environment' (p < 0.05). The age-adjusted prevalence rate of Parkinson's disease revealed at least a 42.5% increase in the disease compared to 1966. We conclude that there may be an increase in the disease in Australia due to ageing and other risk factors.

Aged↗

PubMed2001

Evaluation of learning effectiveness in endotracheal intubation by the use of a laryngoscope in combination with a flexible fiberoptic bronchoscope.

BACKGROUND: Accidental esophageal intubation may cause lethal complications when undetected. We developed a laryngoscope, which utilizes a laryngoscope blade incorporating with a flexible fiberoptic bronchoscope for teaching new learners. We compared two teaching methods, i.e. the traditional method and the new method we contemplated, for teaching new interns. METHODS: We selected new interns as our study group. Everyone had six turns, four of which for the traditional method (T) and two of which for the new method (N), to perform the procedure under the guidance of a teaching supervisor. The interns were assigned randomly to one of three groups. Group 1 used the series of TTTTNN; group 2, TTNNTT; and group 3, NNTTTT. We used success or failure of intubation as the result of our evaluation. Statistical analyses were performed by chi-square test. RESULTS: 84 interns performed 504 endotracheal intubation trials during a period of 4 years. There was a 91.7% success rate with the new method and a 78.9% success rate with the traditional technique (P < 0.05). The group to which the new method was initially taught achieved the highest success rate of intubation and the greatest feeling of satisfaction according to a self-evaluation record. Of the failed intubations, 82.4% were due to performing the procedure in more than one minute, 15.3% due to esophageal intubation and the remaining 2.3% due to contact bleeding of teeth or oral trauma. CONCLUSIONS: By using the new teaching method, the supervisor could easily teach and assess the success of the new learners. Besides, esophageal intubation could be reduced to a minimum with subsequent increase of success rate.

Anesthesiology↗

PubMed2000

On-road motor vehicle emissions and fuel consumption in urban driving conditions.

This paper reports on the analysis of on-road vehicle speed, emission, and fuel consumption data collected by four instrumented vehicles. Time-, distance-, and fuel-based average fuel consumption, as well as CO, HC, NOx, and soot emission factors, were derived. The influences of instantaneous vehicle speed on emissions and fuel consumption were studied. It was found that the fuel-based emission factors varied much less than the time- and distance-based emission factors as instantaneous speed changed. The trends are similar to the results obtained from laboratory tests. The low driving speed contributed to a significant portion of the total emissions over a trip. Furthermore, the on-road data were analyzed using the modal approach. The four standard driving modes are acceleration, cruising, deceleration, and idling. It was found that the transient driving modes (i.e., acceleration and deceleration) were more polluting than the steady-speed driving modes (i.e., cruising and idling) in terms of g/km and g/sec. These results indicated that the on-road emission measurement is feasible in deriving vehicle emissions and fuel consumption factors in urban driving conditions.

Automobile Driving↗

PubMed2000

Validating a screening questionnaire for parkinsonism in Australia.

Parkinson's disease is a common neurodegenerative disorder in elderly people. Epidemiological studies of the disease can be labour intensive. A two phase design including a screening questionnaire as the first phase has become a popular method in prevalence studies of Parkinson's disease. Such a design has many advantages including less work for assessing physicians and enhanced recruitment of people to be screened. However, its wider application may be questioned because validation has been limited to samples that are drawn from hospitals (or clinics) and may be inappropriate for a community setting. This study assesses whether validating screening questionnaire by using a hospital sample yields the same result as a community based sample. Furthermore, it seeks to establish whether the screening instrument can be simplified to involve less questions. The findings show that some of the questions used in the screening phase yield different responses when comparing a hospital group with a community group. This study also provides a simplified model of questions that may be relevant for screening in the community setting.

Aged↗

PubMed1999

Influence of fibrinogen and haematocrit on erythrocyte sedimentation kinetics.

This study investigates the influence of haematocrit, fibrinogen concentration and fibrinogen availability (amount of fibrinogen per red blood cell) on erythrocyte sedimentation. The Westergren technique was applied to blood samples from 36 subjects and to their blood manipulated to haematocrits of 10, 20, 30 and 40%. Readings were taken every 10 minutes for 300 minutes. Previous studies indicate that erythrocyte sedimentation occurs in three phases. In this study, we show that haematocrit has little influence on either the rate of fall of particles in the first phase (m1) or the duration of the first phase. This is also true for fibrinogen availability and for fibrinogen concentration at low haematocrits. At high haematocrits m1 increases with fibrinogen concentration. The rate of fall of rouleaux during phase 2 (m2) and ESR60 both decrease exponentially with haematocrit and increase linearly with fibrinogen concentration. While m2 is more closely correlated to fibrinogen availability than to fibrinogen concentration or to haematocrit, this is not the case for ESR60. Thus haematocrit, fibrinogen concentration and fibrinogen availability are more important to the velocity of sedimentation in the second phase than to the sedimenting velocity during phase 1 or to the duration of phase 1.

Adult↗

PubMed1998

Hepatocellular carcinoma in children: clinical review and comparison with adult cases.

BACKGROUND: Hepatocellular carcinoma (HCC) in children was rarely reported and usually included with hepatoblastoma in most studies of pediatric liver malignancies despite different clinical behaviors. The authors report their experience in pediatric HCC and discuss its differences from adult HCC. METHODS: A retrospective review of radiographic, laboratory, pathological, and therapeutic data in 55 children with HCC was performed. The liver function was graded by modified Child's classification. Kaplan-Meier survival curves in various therapeutic and Child's groups were plotted, and log-rank test was used to detect differences among survival curves. RESULTS: Although children with HCC mostly presented with advanced disease at diagnosis, disturbances of liver function were unremarkable. Sixty-eight percent of cases concurred with liver cirrhosis. The median survivals for resectable, chemotherapeutic, and untreated HCCs were 23, 3, and 2 months, respectively. Resectable HCC significantly posed a much better prognosis. However, the resectability was unsatisfactory (18.2%). Resection was limited because of anatomic unfeasibility including bilateral involvement (62.5%), portal vein thrombi (41.7%), distant metastasis (29.1%), para-aortic lymphadenopathy (18.8%), inferior vena cava thrombi (16.7%), and hilar invasion (6.3%). Distant metastasis was the most ominous for survival in children with unresectable HCC. CONCLUSIONS: HCC behaved somewhat differently between children and adults. Surgical resection represented the best hope of long-term survival. The outcome in children could not keep up with that in adults because of a diagnostic delay. Hence, alpha-fetoprotein and sonography screening in carrier children should be worthwhile.

Adolescent↗