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Biomedical subjects

K S Wong

Publications and source records attributed to K S Wong.

At least 19 recordsLinked to original sources

Prospective randomized, double-blind, placebo-controlled study of pre- and postoperative administration of a COX-2-specific inhibitor as opioid-sparing analgesia in major colorectal surgery.

PURPOSE: To demonstrate the opioid-sparing effect and reduction in postoperative ileus obtained with valdecoxib 40 mg administered pre- and postoperatively in patients undergoing colorectal resection. METHODS: Patients for elective colorectal resection from December 2002 to June 2004 were randomized to receive either valdecoxib or placebo with standard patient-controlled analgesia (PCA) morphine. In the study arm, the first dose of valdecoxib 40 mg was administered orally as close as possible to 1 h prior to the start of surgery. Each subsequent dose was administered at 24-h intervals up to 120 h. Patients in the control arm were served placebos at the same time-points. RESULTS: Forty patients were enrolled in the study arm and 39 (excluding one protocol violation) in the control arm. The groups were comparable in age, sex, American Society of Anesthesiology status, body mass index, incision length, and duration and types of operations. Mean PCA doses at 12 and 24 h were 18.6 and 28.3 mg in the study arm vs 26.2 and 41.2 mg in controls, representing a one-third opioid reduction. Bowel sound and movement first appeared at medians of 12 and 72 h in the study arm vs 24 and 84 h, respectively, in controls (P < 0.05). Tolerance of solid diet was at a median of 60 h and discharge at a median of 4 days in the study arm vs 72 h and 6 days in controls (P < 0.05 and P < 0.01, respectively). Seven (18%) morbidities occurred in the control vs six (15%) in the study arm. CONCLUSIONS: Patients treated with a cyclo-oxygenase 2-specific inhibitor have a shorter recovery time when compared with patients on a standard postoperative PCA morphine-only regimen after colorectal resection.

Adult↗

Microfabricated discontinuous-edge surface topographies influence osteoblast adhesion, migration, cytoskeletal organization, and proliferation and enhance matrix and mineral deposition in vitro.

The fabrication of surfaces that stimulate increased adhesion, migration, and differentiated function of osteoblasts has been viewed as being desirable for many orthopedic applications. Previous studies have shown that microfabricated pits and grooves alter adhesion, spreading, matrix secretion, and production of mineral by rat calvarial osteoblasts (RCOs). The mechanisms underlying these effects are unknown, although microenvironment and cell alignment are considered to play a role. The aim of this work was to investigate the behavior of RCOs on microfabricated discontinuous-edge surfaces (DESs), which could provide an alternative means to control both the microenvironment and cellular alignment. Two types of discontinuous-type structures were employed, gap-cornered boxes and micron scale pillars. DES gap-cornered boxes and the pillars influenced the arrangement of F-actin, microtubules, and vinculin. Osteoblasts were guided in their direction of migration on both types of substrata. Both box DESs and pillars altered the staining intensity and localization pattern of phosphotyrosine and src-activated FAK localization. Cell multilayering, matrix deposition, and mineralization were enhanced on both discontinuous topographies when compared with smooth controls. This study shows that DESs alter adhesion, migration, and proliferative responses from osteoblasts at early time points (<1 week) and promote multilayering, matrix deposition, and mineral deposition at later times (2-6 weeks). Such topographical patterns could potentially be employed as effective surface features on bone-contacting implants or in membrane-based periodontal applications.

Actins↗

Association of smoking with increasing vascular involvement in type 2 diabetic Chinese patients.

PURPOSE: To identify the relationship between smoking and the metabolic profile and existing vascular disease in Chinese type 2 diabetic patients. METHODS: 1710 diabetic patients were screened for complications, and biochemical and anthropometric vascular risk factors. As most smokers were male, differences were only compared between male current (n = 196) and never smoking patients (n = 300). RESULTS: The smokers had higher glycosylated haemoglobin levels (8.2 +/- 2.0 vs. 7.6 +/- 1.8%, p < 0.001) than never smokers, despite a greater proportion receiving hypoglycaemic agents (87.5 vs. 79.6%, p = 0.003). Male smokers compared to never smokers had lower HDL-cholesterol levels (1.12 +/- 0.31 vs. 1.20 +/- 0.30 mmol/L, p = 0.006), and elevated albumin-to-creatinine ratio (3.57 [2.68-4.75] vs. 2.47 [1.99-3.05] mg/mmol, p = 0.040). However, diastolic blood pressure was lower in the smoking group (78 +/- 12 vs. 82 +/- 12 mmHg, p = 0.001) even though they received less blood pressure-lowering treatments (23.8 vs. 33.2%, p = 0.034). The prevalence of peripheral vascular disease was increased in the diabetic patients who smoked compared to nonsmokers (7.1 vs. 2.8%, p = 0.039). CONCLUSIONS: Smoking was associated with a more adverse metabolic profile and peripheral vascular disease. As mainland China undergoes rapid modernisation and urbanisation, the observed effects of smoking means tobacco control becomes increasingly important to prevent or minimise potential health impacts and chronic disease.

Adult↗

Apolipoprotein E epsilon4 allele is associated with the volume of white matter changes in patients with lacunar infarcts.

The relationship between the apolipoprotein E (APOE) exon 4 polymorphism and white matter changes (WMC) in elderly subjects or patients with Alzheimer's disease is controversial. To investigate this polymorphism in relation to WMC in patients with lacunar infarcts, we prospectively observed 67 patients with acute lacunar infarct and 134 age- and sex-matched controls. Genotypes were determined using a nested polymerase chain reaction. WMC were measured quantitatively and were divided into two groups, severe and mild, with the mean volume of WMC as the cut point. Twenty-two patients (33%) had severe WMC. There was a significant difference in the distribution of APOE epsilon2, epsilon3, and epsilon4 alleles between severe and mild WMC groups (P = 0.002). The frequency of epsilon4 alleles was higher in patients with severe WMC than in those with mild WMC (25% vs. 7%, P = 0.003). These results suggest that APOE epsilon4 may exacerbate WMC in patients with lacunar infarcts. Further studies are required to confirm this finding.

Aged↗

Sublingual misoprostol compared to artificial rupture of membranes plus oxytocin infusion for labour induction in nulliparous women with a favourable cervix at term.

OBJECTIVES: To compare the efficacy of labour induction using sublingual misoprostol versus combined artificial rupture of membranes and oxytocin infusion for nulliparous women with a favourable cervix at term. DESIGN: Open randomised controlled trial. SETTING: Regional hospital, Hong Kong. PATIENTS: Fifty nulliparous women with a favourable cervix (Bishop score 6 or more) at term and indications for labour induction. INTERVENTIONS: With their informed consent, 100 eligible women were to be randomised to receive either sublingual misoprostol 50 micrograms every 4 hours for up to five doses or oxytocin infusion after artificial rupture of membranes. Interim analysis was planned at a sample size of 50. MAIN OUTCOME MEASURES: Vaginal delivery within 24 hours of induction. RESULTS: The study was terminated when interim analysis of the first 50 recruits showed that a significantly smaller proportion of misoprostol-treated women delivered vaginally within 24 hours of induction than in the conventional treatment group (68% vs 100%; relative risk, 0.68; 95% confidence interval, 0.51-0.91; P=0.009), although comparable numbers of women eventually delivered vaginally. The mean induction to vaginal delivery interval was 4.5 hours longer in the misoprostol group (P=0.027). After misoprostol treatment, all women went into labour. Forty percent of them delivered without oxytocin. There was no significant difference in uterine hyperstimulation rate, operative delivery rate, and neonatal outcomes. Maternal satisfaction was higher in the misoprostol group (92% vs 60%; relative risk, 1.53; 95% confidence interval, 1.09-2.16; P=0.008). CONCLUSIONS: Despite being well accepted by women, labour induction using this regimen of sublingual misoprostol is less effective in achieving vaginal delivery within 24 hours.

Administration, Sublingual↗

Potential value of post stroke extracranial arterial blood flow volume in the prediction of stroke functional outcome.

BACKGROUND AND PURPOSE: Cerebral vasoreactivity and collateral circulation are important protective mechanisms against cerebral ischemia. Previous studies suggest that the efficiency of these mechanisms can be reflected by extracranial arterial blood flow volume. Brain damage leading to neurological impairments can influence patients' functional recovery after stroke. This study attempted to explore the potential value of post stroke extracranial arterial blood flow volume in the prediction of stroke patients' functional outcome. METHODS: We prospectively studied 362 consecutive patients who were hospitalized for recent acute strokes. All patients underwent extracranial arterial blood flow volume measurement of the carotid and vertebral arteries by color velocity imaging quantification within 3 days after admission. Their functional recovery was assessed 6 months after stroke. The effect of post stroke extracranial arterial blood flow volume on patients' functional outcome was tested by multivariate ordinal regression after controlling for other independent variables. Significance was at p<0.05. RESULTS: Post stroke extracranial arterial blood flow volume together with age, pre-stroke modified Rankin scale, the National Institutes of Health Stroke Scale and diabetes mellitus had significant effects on the patients' 6-month functional outcome as measured by the modified Rankin scale after controlling for other independent variables (p<0.05). CONCLUSIONS: Post stroke extracranial arterial blood flow volume is an independent outcome predictor. The graded predictive power of this parameter is potentially more superior than other outcome predictors by allowing classification of stroke outcome according to the degree of severity. A large prospective study is thus warranted to investigate its clinical value in the management of stroke patients.

Adult↗

Storage and release of femtosecond laser pulses in a resonant photonic crystal.

Femtosecond laser pulses with suitable pulse areas are shown to decelerate and stop inside a resonant photonic crystal. The release of the stored fields can be achieved through pulse collision by use of an external optical pulse as a control field. The duty cycle efficiency of the storage and release of light is shown to be as much as 96%. The proposed technique is applied to a real photonic system with finite thickness of atomic layers.

Journal Article↗

Scoring system for empyema thoracis and help in management.

OBJECTIVE: To evaluate the implications of a newly defined severity scoring of empyema in children for the prediction of surgical management and to compare the length of hospitalization as an outcome measure of patients treated using medical therapy, salvage video-assisted thoracoscopic surgery (VATS) vs early elective VATS. METHODS: A retrospective chart review of parapneumonic empyema of patients below 18 years of age admitted to a tertiary children's hospital in northern Taiwan from April 1993 to December 2002 was performed. Patients were categorized into a medical group who received antibiotic therapy, needle aspirations with/without tube thoracostomy; a salvage VATS group when the patients required surgery for the relief of persistent fever > 38 degrees C, chest pains or dyspneic respirations despite initial medical therapy; an early VATS group when the patients received elective surgery early after admission. The demographic data, clinical features, laboratory findings, and duration of hospitalization were compared using a severity score of empyema (SSE). RESULTS: Streptococcus pneumoniae was the most common infecting organism, followed by Staphylococcus aureus, Pseudomonas aeruginosa. No organisms were recovered in 39% of patients. A pleural pH < 7.1 increases the odds of requiring surgical intervention by 6 times among this cohort. Children who required decortication of empyema had a higher severity score (mean 4.8 vs 3.0, p < 0.005). The duration of hospitalization for patients having early VATS showed a shortening stay (mean 18 vs 28 days) as compared to salvage VATS. CONCLUSION: A pleural pH < 7.1 and a newly designed clinical severity score of empyema 4 are two predictors of surgical intervention for fibrinopurulent empyema in the present study. Early elective VATS may be adopted not later than 7 days after failure of appropriate antibiotic therapy and adequate drainage of empyema to decrease the length of stay and minimize morbidity.

Adolescent↗

Electrophysiological, clinical and epidemiological study of Guillain-Barre Syndrome in Hong Kong Chinese.

The authors reviewed the clinical and electrophysiological features in 20 consecutive adult patients with Guillain-Barre Syndrome (GBS) admitted to a regional hospital in Hong Kong from 1993 to 1998. The majority of cases in this locality consists of the demyelinating form of GBS; epidemic, acute motor axonal neuropathy is not the predominant form. The incidence of GBS in this region of China was 0.44 per 100,000.

Adult↗

Extent of white matter lesions is related to acute subcortical infarcts and predicts further stroke risk in patients with first ever ischaemic stroke.

OBJECTIVE: To investigate whether the extent of white matter lesions (WML) on fluid attenuated inversion recovery (FLAIR) MRI sequences is an independent risk factor for recurrent stroke, and to document the pattern of acute cerebral infarcts using diffusion weighted imaging (DWI) in patients with different severities of WML. METHODS: In a prospective cohort study, 228 consecutive stroke patients were studied between 1999 and 2001 in a community hospital. The severity of WML was graded as 0 (no WML), 1 (mild), 2 (moderate), or 3 (severe) according to the FLAIR appearances. DWI was used to document the location and size of the infarct. RESULTS: 31 patients had grade 0 WML, 69 had grade 1, 59 had grade 2, and 69 had grade 3. Age was independently associated with WML on logistic regression analysis (p = 0.0001). Acute cerebral infarcts in deep white matter were correlated with increasing severity of WML. On a median follow up of 23.0 months, life table analysis showed that recurrent stroke was related to the severity of WML (recurrence rate 7.8% in grade 0, 9.3% in grade 1, 17.7% in grade 2, 43.7% in grade 3; p = 0.0001). Survival was reduced in patients with severe WML (p = 0.0068). A Cox proportional hazards model showed WML to be predictive of recurrent stroke (p = 0.000, hazard ratio = 4.177 (95% confidence interval, 2.038 to 8.564)) and also for survival (p = 0.040, hazard ratio = 2.021 (1.032 to 3.960)). CONCLUSIONS: Patients with severe leukoaraiosis have increased risk of deep subcortical stroke and a higher risk of recurrent stroke.

Acute Disease↗

Appropriate use of personal protective equipment among healthcare workers in public sector hospitals and primary healthcare polyclinics during the SARS outbreak in Singapore.

BACKGROUND: Singapore was affected by an outbreak of severe acute respiratory syndrome (SARS) from 25 February to 31 May 2003, with 238 probable cases and 33 deaths. AIMS: To study usage of personal protective equipment (PPE) among three groups of healthcare workers (HCWs: doctors, nurses, and administrative staff), to determine if the appropriate PPE were used by the different groups and to examine the factors that may determine inappropriate use. METHODS: A self-administered questionnaire survey of 14,554 HCWs in nine healthcare settings, which included tertiary care hospitals, community hospitals, and polyclinics, was carried out in May-July 2003. Only doctors, nurses, and clerical staff were selected for subsequent analysis. RESULTS: A total of 10 236 valid questionnaires were returned (70.3% response); 873 doctors, 4404 nurses, and 921 clerical staff were studied. A total of 32.5% of doctors, 48.7% of nurses, and 77.1% of the administrative staff agreed that paper and/or surgical masks were "useful in protecting from contracting SARS". Among this group, 23.6% of doctors and 42.3% of nurses reported working with SARS patients. The view that a paper and/or surgical mask was adequate protection against SARS was held by 33.3% of doctors and 55.9% of nurses working at the A&E unit, 30.5% of doctors and 49.4% of nurses from medical wards, and 27.5% of doctors and 37.1% of nurses from intensive care units. Factors which predicted for agreement that paper and/or surgical masks were protective against SARS, included HCW's job title, reported contact with SARS patients, area of work, and Impact Events Scale scores. CONCLUSION: A variety of factors determine appropriate use of personal protective equipment by HCWs in the face of a major SARS outbreak.

Administrative Personnel↗

Clinical characteristics of tuberculosis in children in the north of Taiwan.

Tuberculosis (TB) in children is an endemic and sometimes life-threatening disease in Taiwan. This study analyzed the clinical characteristics of a total of 112 children with TB managed in a referral children's hospital in the north of Taiwan between 1998 and 2002. The diagnosis of TB was made by either a positive result of culture, acid-fast stain, histopathology, or polymerase chain reaction (PCR). Tuberculin skin test was positive (indurations > or =10 mm) in 73% of 63 patients tested. The male-to-female ratio was 0.93 (54/58), and the mean age was 10.7 years. Thirty one percent of children were younger than 6 years of age, 12% were 6 to 12 years old, and 57% were older than 12 years. Fifty percent (50/100) of these children had household members with TB; 29.2% (31/106) were aboriginal; 93% had received Bacille Calmette-Guerin (BCG) vaccine. Isolated pulmonary TB was diagnosed in 65 cases (58%), extrapulmonary TB in 25 (22%), and combined intra- and extrapulmonary TB in 22 (20%). Fever was not a presenting symptom in 30.4% of children, was low grade (<38.5 degrees C) in 23.2% and was high grade (> or =38.5 degrees C) in 46.4%. The mean duration of fever was 13.9 days. Patients with combined intra- and extrapulmonary TB had a significantly longer hospital stay (p<0.001), a higher peak body temperature (p<0.001), and a longer duration of fever (p=0.024). Patients with extrapulmonary TB had a significantly lower incidence of fever (p=0.001), a lower segment count (p=0.007) and a lower serum C-reactive protein level (p=0.019). Ventriculoperitoneal shunt insertion was performed in 8 of 12 cases with central nervous system involvement. Among 21 cases of TB osteomyelitis, tibia (33%) and spine (33%) were the most common sites of involvement. The overall mortality rate was 3.6% (4/112). Extrapulmonary TB and combined intra- and extrapulmonary TB were more commonly seen in children with a younger age and in those who had not received BCG vaccination. This study found that household members with TB history and aboriginal ethnicity were strongly associated with TB in Taiwanese children. Multidrug-resistant TB was uncommon in children born before the year 2003.

Adolescent↗

ATRA therapy restores normal renal function and renal reserve and prevents renal failure.

This article presents clinical data which suggest that the current dosage of losartan 50 to 100 mg/day may not be the optimum in many cases, especially if used as monotherapy in the treatment of proteinuria and we may have to increase to 200 mg/day. However, about 30% of patients cannot take angiotensin-converting enzyme inhibitor (ACEI) because of the side effect of cough. To potentiate the anti-proteinuric effect of losartan, especially for patients who do not adhere to a low salt diet, a 12.5-mg dose of hydro-chlorothiazide may further decrease proteinuria. The main message of this article is that we would have to, in many instances, increase the dose of losartan to a minimum of 100 mg/day or 100 mg twice a day for some patients for optimal therapy. The second message is to monitor the creatinine clearance test (CCT) and to start therapy when CCT is reduced and not wait for serum creatinine to rise to abnormal levels (renal impairment) before starting therapy. The first group involves half a dozen patients with hypertension but no proteinuria. Therapy with losartan is shown to improve the renal function. This data suggest that losartan, apart from its use in reduction of proteinuria, can be used in patients with mild renal impairment without proteinuria to reverse the mild renal impairment and preserve renal function. The second group deals with 3 patients with low creatinine clearance. After a followup period of an average of 3 years, they all developed renal impairment. In another 6 patients, the data suggest that we should perhaps treat patients with low CCT as soon as possible and with dose ranging from 100 to 200 mg/day if necessary, to derive maximum beneficial effect. The third group highlights 5 patients with high CCT due to glomerular hyperfiltration. With time, the high CCT decreases and renal impairment sets in. The data suggest that patients with high CCT should be treated early to prevent renal impairment. The fourth group illustrates 6 patients where their proteinuria was markedly reduced with the increase of losartan from 100 mg/day to 200 mg/day, suggesting that losartan 200 mg/day is probably the optimum dose. In conclusion, apart from its traditional usage in reduction of proteinuria to retard progression to renal failure, the data suggest that losartan is also indicated in patients with renal impairment in the absence of proteinuria; patients with low CCT, patients with high CCT and patients who do not respond to a dosage of 100 mg/day should have the dosage increased to 100 mg twice daily to increase efficacy of losartan. It is hoped that with these new and earlier indications as well as increased dosage of losartan starting with 100 mg, whenever possible, and increasing to 200 mg/day, if there is no response, we can prevent more patients from developing renal failure. Based on these observations, further randomised controlled trials should be designed to address these issues.

Adult↗

Laparoscopic-assisted colon and rectal surgery - lessons learnt from early experience.

INTRODUCTION: Current evidence shows that laparoscopic bowel surgery is associated with a lower incidence of postoperative ileus, lower postoperative pulmonary and wound complication rates, shorter hospital stays and a quicker return to activity than open surgery. This paper aims to report our early experience with laparoscopic-assisted colorectal procedures in our Centre for Advanced Laparoscopic Surgery and the important lessons we have learnt from this. MATERIALS AND METHODS: All laparoscopic-assisted colon and rectal surgical (LAC) procedures performed between January 2000 and December 2003 were reviewed. Clinical and operative records of these patients were reviewed. Data retrieved included patient demographics, selected intraoperative parameters, and postoperative outcomes. In order to provide a comparable reference, an equal number of matched open procedures over the same period were accrued and similarly analysed. All patients were managed on a standard carepath. All data were entered into a database and analysed using a statistical software package. RESULTS: Forty-two laparoscopicassisted colorectal procedures were performed from June 2000 to December 2003. A similar number of diagnosis-matched patients with open colorectal procedures were used as comparison. The diagnoses included cancer (68.5% versus 73.8%), diverticulosis (5.7% versus 9.5%) and polyps (14.3% versus 9.5%). Seven were converted to open surgery because of bleeding, adhesions and locally advanced disease. Laparoscopic-assisted procedures performed included 1 right hemicolectomy, 5 left hemicolectomies, 9 anterior resections, 1 abdominal-perineal resection, 3 sigmoid colectomies, 11 colostomies and 1 Hartmann's procedure. Mean perioperative time (146 min versus 125 min, P = 0.173) was comparatively longer. Mean duration for analgesic requirement (2.25 days versus 2.64 days, P = 0.05), mean length of stay (5.31 days versus 9.07 days, P < 0.05), mean time to commencement of diet (2.91 days versus 4.05 days, P < 0.001) and mean time to first bowel movement (2.57 days versus 4.10 days, P < 0.001) were all comparatively shorter. General morbidity rates (17.1% versus 21.4%, P = 0.35) were lower. No local wound complications were found in our laparoscopic-assisted group. Patients who had undergone open surgery instead of the planned laparoscopic-assisted procedures fared more poorly. CONCLUSIONS: Laparoscopic-assisted colorectal procedures performed in well-selected patients are associated with shorter hospital stays, quicker return of bowel function and lower morbidity when compared to the matched open procedures. Early experience should be acquired from performing technically simple procedures in patients with benign conditions before progressing to definitive resections in those with cancer.

Adult↗

Multiple acute cerebral infarcts on diffusion-weighted imaging and risk of recurrent stroke.

Multiple acute cerebral infarcts (MACIs) detected by diffusion-weighted imaging (DWI) may indicate an unstable source of thromboembolism. The authors studied 119 consecutive acute ischemic stroke patients within 24 hours of onset with DWI. MACIs were present in 20 patients (16.8%). During the follow-up period, there were 15 recurrent strokes, 3 acute coronary syndromes, and 5 deaths. MACI was the only significant independent predictor for vascular events and death (odd ratio [OR]] = 4.34; p = 0.001) and stroke recurrence (OR = 5.93; p = 0.001).

Acute Disease↗

Albuminuria is a marker of increasing intracranial and extracranial vascular involvement in Type 2 diabetic Chinese patients.

AIMS/HYPOTHESIS: Albuminuria has been reported to be a marker of cardiovascular risk factors and disease morbidity and mortality, but its relationship with intracerebral atherosclerotic disease is less clear. The aim of this study was to investigate the association between albuminuria and intracranial and extracranial vascular involvement in Chinese Type 2 diabetic patients. METHODS: The anthropometric and fasting biochemical measurements of 966 Type 2 diabetic patients with normoalbuminuria (55.6%), microalbuminuria (27.7%) or macroalbuminuria (16.7%) were compared. The prevalence of microvascular and macrovascular disease and middle cerebral artery (MCA) stenosis, measured by transcranial Doppler ultrasound, were also compared between the groups. RESULTS: Albuminuria was closely associated with a range of adverse parameters, including high BP, dyslipidaemia, smoking and adiposity (all p<0.01). The prevalence of microvascular disease (retinopathy p<0.001) and macrovascular disease (peripheral vascular disease p=0.012, myocardial infarction, p=0.004, MCA stenosis p<0.001) increased significantly with increasing levels of albuminuria. Albuminuria was also found to be an independent predictor of microvascular and macrovascular disease. CONCLUSIONS/INTERPRETATION: Albuminuria was an independent predictor of increasing levels of vascular risk factors and microvascular and macrovascular disease in this group of Type 2 diabetic patients, and a possible role for albuminuria as a marker of intracranial cerebrovascular disease should be further investigated.

Aged↗