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Biomedical subjects

K H Wong

Publications and source records attributed to K H Wong.

At least 19 recordsLinked to original sources
PubMed2006

Evaluation of NucliSens EasyQ HIV-1 assay for quantification of HIV-1 subtypes prevalent in South-east Asia.

BACKGROUND: Monitoring anti-retroviral therapy requires that viral load assays for human immunodeficiency virus type 1 (HIV-1) be applicable to diverse HIV-1 subtypes. OBJECTIVES: To evaluate NucliSens EasyQ HIV-1 assay for quantitation of common HIV-1 subtypes prevalent in South-east Asia. STUDY DESIGN: One hundred and nineteen plasma samples collected in Hong Kong and Cambodia were used to compare the performance of NucliSens EasyQ HIV-1 and COBAS Amplicor HIV-1 Monitor version 1.5 assays. Viral RNA extracted from the NucliSens MiniMAG was also used for HIV-1 subtyping. RESULTS: Performance of NucliSens EasyQ correlated well with COBAS Amplicor (r=0.777, p<0.001) and the small mean difference (0.0462log(10)IU/mL) obtained in the Bland and Altman model indicated good agreement between two assays. The NucliSens EasyQ assay demonstrated a 95% sensitivity at 500IU/mL and 100% specificity. Reproducibility of this assay was within log(10)2-4IU/mL and had a coefficient of variation between 2.3% and 10.4%. Among the 109 specimens included in the analysis, HIV-1 subtyping identified 64 CRF01_AE, 38 subtype B, 3 subtype C, 3 CRF07_BC and 1 subtype G viruses. CONCLUSIONS: Performance of NucliSens EasyQ was comparable to COBAS Amplicor for HIV-1 viral load monitoring. RNA extracts from NucliSens MiniMAG could be used for HIV-1 viral load monitoring, subtyping and drug resistance mutations detection. Our findings highlight the versatility of both NucliSens EasyQ and COBAS Amplicor in monitoring prevalent subtypes and rare circulating recombinant forms (CRFs) in the South-east Asia region.

Cambodia↗
PubMed2006

Comparison of assessment tools to score recovery of function after repair of traumatic lesions of the median nerve.

In this paper the recovery after repair of the median nerve has been used to compare different assessment tools for evaluation of peripheral nerve function: touch (moving 2-point discrimination (2PD); Semmes-Weinstein (SW) monofilament, motor (Medical Research Council (MRC) scale), combined motor and sensory (Dellon modification of the Moberg pick up test; Moberg Recognition test), and pain (visual analogue scale; pinprick-test). The mean (SD) age of our 28 patients was 28 (12) years. The mean (SD) follow-up period was 5 years, 2 months (2 years, 8 months). On the operated side three patients (11%) had a moving 2PD of less than 4 mm. The results of the moving 2PD were compared with those of the SW monofilaments, but with a poor correlation. The MRC score correlated well with opposition movement of the thumb and muscle wasting (p<0.01). We recommend a number of tests to evaluate (the chronological return of) peripheral nerve function.

Adult↗
PubMed2006

Universal decline in mortality in patients with advanced HIV-1 disease in various demographic subpopulations after the introduction of HAART in Hong Kong, from 1993 to 2002.

OBJECTIVE: Reductions in HIV/AIDS mortality associated with highly active antiretroviral therapy (HAART) have mainly been reported from Western countries. We studied the impact on survival of patients with advanced HIV disease after the introduction of HAART in Hong Kong. METHODS: The mortality pattern in a government clinic cohort of 511 adult HIV-1-infected patients with AIDS or CD4 count <200 cells/microL from 1993 to 2002 was examined. The number of deaths, the crude mortality rate (CMR) and the death rate per 1000 person-months were recorded. RESULTS: Despite an increase in the patient population, 36 deaths occurred in the HAART era (1997-2002) as compared with 56 deaths in the pre-HAART era (1993-1996). The overall annual CMR fell significantly from a high, fluctuating level of 10.8-30.4 per 100 mid-year patient population pre-HAART to a low, steady level of 0.8-6.9 per 100 mid-year population in the HAART era (P=0.004, 1996 vs 1998; P<0.001, 1996 vs 2000; P<0.001, 1996 versus 2002). A fall in CMR was observed in all demographic subpopulations, categorized by sex, ethnicity, HIV exposure risk and age (P ranged from 0.012 to<0.001). Longitudinal tracking until mid-2003 revealed a death rate of 9.2 events/1000 person-months (52 deaths with 5661.5 person-months follow up) among patients first diagnosed as having advanced disease during 1993-1996, and a lower death rate of 2.4 events/1000 person-months (25 deaths with 10551.8 person-months follow up) in patients first diagnosed as having advanced disease during 1997-2001 (rate ratio 3.9; 95% confidence interval 2.4-6.2). CONCLUSION: There was dramatic temporal decline in mortality in patients with advanced HIV disease in all demographic subpopulations with the advent of HAART. Notwithstanding confounding variables, one reason for the universal decline may be that there was no major disparity in access to HIV care across community groups.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Twenty years of clinical human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) in Hong Kong.

OBJECTIVE: To elucidate the development of human immunodeficiency virus (HIV) clinical care and research in Hong Kong. DATA SOURCES: Articles on clinical HIV and acquired immunodeficiency syndrome (AIDS) published from 1985 to 2004 were identified through four sources: Red Ribbon Centre, Special Preventive Programme, Secretariat of the Scientific Committee on AIDS, and PubMed search. The first three are operated by the Centre for Health Protection, Department of Health, Hong Kong. STUDY SELECTION: Key words for the literature search were 'AIDS', 'HIV', and 'Hong Kong'. DATA EXTRACTION: Only papers with original local data were included. DATA SYNTHESIS: Sixty papers were identified. The contents were catalogued under seven areas: clinical epidemiology, HIV disease course and presentation, specific complications or organ-based manifestations, immunological evaluation and other monitoring, antiretroviral therapy, HIV/AIDS mortality, and HIV in specific groups. Prevalence of HIV has remained low in Hong Kong but new infections continue to occur together with a significant number of late presenters. Three published AIDS patients' series, up to the first 200 reported cases, identified Pneumocystis carinii pneumonia as the most common AIDS-defining illness in Hong Kong. Penicillium marneffei and Mycobacterium tuberculosis were two important specific infections studied most; uniqueness of the former in patients of South-East Asia was evident. Local studies of Kaposi's sarcoma and HIV-associated lymphoma have also been reported. Research on CD4 counts has revealed that it is lower in healthy and HIV-infected Chinese than their western counterparts. Children, pregnant women, and haemophiliac patients infected with HIV are among the specific groups of patients studied. Survival of patients with advanced disease has greatly improved over the years, particularly after the advent of highly active antiretroviral therapy. CONCLUSION: The clinical presentation and outcome of HIV/AIDS patients in Hong Kong are a mixture of those of western and developing countries. Research on clinical HIV/AIDS in Hong Kong is not only beneficial to the planning of patient care, but also enables the formulation of treatment guidelines and provides a reference for other countries.

HIV Infections↗
PubMed2006

Spontaneous pneumomediastinum in a scuba diver.

Pneumomediastinum usually occurs following an airleak from the lungs, or from a perforated oesophagus. We report on a 30-year-old man who developed pneumomediastinum after scuba diving. The patient presented with acute onset of throat pain, odynophagia, and hoarseness of voice. The literature is reviewed for this condition.

Adult↗
PubMed2005

Clinical utility of genotyping resistance test on determining the mutation patterns in HIV-1 CRF01_AE and subtype B patients receiving antiretroviral therapy in Hong Kong.

BACKGROUND: HIV-1 genotypic resistance test (GRT) has been widely used to monitor HIV infection but only few reports revealed the mutation patterns of non-B HIV-1 subtypes. OBJECTIVE: To evaluate the concordance of GRT and clinical treatment outcomes on different HIV-1 subtypes and monitor the mutation patterns and frequencies. STUDY DESIGN: Pre- and post-treatment plasma samples from 123 patients (39 treatment naïve and 84 treatment experienced) were tested by ViroSeq HIV-1 Genotyping System followed by analysis using the Stanford HIV database. The mutation patterns and frequencies developed in the pol gene were compared among subtypes. RESULTS: HIV-1 subtypes among patients in Hong Kong were mainly subtype B and CRF01_AE. Primary mutation was not detected among all pre-treatment samples. For post-treatment samples, primary mutations were only detected in the treatment failure group. The mutation patterns and frequencies were similar between CRF01_AE and subtype B viruses. However, the frequencies of L74V/I and K103N in the reverse transcriptase region were different between CRF01_AE and subtype B viruses. VirtualPhenotype was unable to analyze an in-frame insertion of arginine and isoleucine at protease codon 35 of one CRF01_AE isolate. CONCLUSIONS: This is the first report to demonstrate the high degree of concordance of longitudinal genotyping data and clinical treatment outcome in patients harboring different HIV-1 subtypes. Our findings shed light to the emergence of resistance mutations and its testing in CRF01_AE, which is relevant to other prevailing places in Asia.

Algorithms↗
PubMed2004

Optimization of photocatalytic oxidation of 2,2',3,3'-tetrachlorobiphenyl.

Polychlorinated biphenyls (PCBs) are wide spread environmental pollutants. This research focused the optimum physico-chemical conditions under which photocatalytic oxidation (PCO) can be used to degrade 2,2',3,3'-tetrachlorobiphenyl (tetra-CB). Among the optimal physico-chemical conditions studied were UV intensity, hydrogen peroxide (H2O2) and titanium dioxide (TiO2) concentrations, initial pH, and possible reaction intermediates were also determined. The results indicate that the optimal physico-chemical conditions necessary for the degradation of tetra-CB by PCO were UV intensity at 3.16 mW/cm2, 30 mM of H2O2 and 100 mg/l of TiO2. In contrast to the results of PCO studies on other organic compounds, the optimum pH for PCO degradation of tetra-CB was 5.5. The removal efficiency was also higher under acidic conditions than alkaline conditions. Although degradation intermediates such as 1,3-bis(1,1-dimethylethyl)benzene, 2,4-bis(1,1-dimethylethyl)phenol, and 3,5-di-tert-butyl-4-hydroxybenzaldehyde were identified at an early stage in the reaction process, they were not completely degraded even after 7h of PCO reaction.

Catalysis↗
PubMed2004

Epidemiology of hepatitis A and hepatitis E infection and their determinants in adult Chinese community in Hong Kong.

Current epidemiology of hepatitis A virus (HAV) and hepatitis E virus (HEV) in Hong Kong was evaluated in 936 adult Chinese subjects recruited through a telephone interview in 2001. Some 15% of the subjects had IgG antibodies to both HAV and HEV while 665 (71.0%) and 176 (18.8%) had anti-HAV and anti-HEV, respectively. Age was the most significant independent factor. Six hundred thirty-eight (79.8%) and 165 (20.7%) subjects aged > or =30 had anti-HAV and anti-HEV, respectively, as compared with 27 (19.7%) and 11 (8.0%) in people aged <30. The corresponding adjusted Odds ratio (OR) was 14.94 (95% CI: 9.13-24.44; P<0.001) for anti-HAV positivity and 2.99 (95% CI: 1.58-5.67; P=0.001) for anti-HEV positivity. Subjects born outside Hong Kong were more likely to have anti-HAV (adjusted OR: 3.41; 95% CI: 2.21-5.26; P<0.001) but not anti-HEV. Non-labour work people were less likely to have anti-HAV-adjusted OR, 0.40 (95% CI: 0.26-0.62; P<0.001). Age-specific HAV prevalence right shifted in the last 20 years. Anti-HAV positivity was less frequent, across all age groups, in subjects >21-years-old in the present study than another study done in 1987-89 (P<0.001). HAV prevalence only increased slightly in every 10-year age groups of people aged 21-50 when compared with their corresponding 10-year-younger age groups (P=0.11), suggesting an ageing cohort effect with no major infections in the last decade. For HEV, both the overall and age-specific prevalence decreased over the last decade (P<0.001). The increasing proportion of susceptible population to enterically transmitted viral hepatitis has implications to future prevention and control programmes, including vaccination strategies.

Adolescent↗
PubMed2004

The lack of epidemiological link between the HIV type 1 infections in Hong Kong and Mainland China.

Blood samples were collected from 139 newly reported HIV-1 infections in Hong Kong over a 3-year period between 1999 and 2001, representing 22.8% of all reported cases. A majority of the patients were male (85.6%), Chinese (74%), and adult (97.1%) and acquired HIV-1 through sexual transmission (88.2%). The B and CRF01_AE were the major subtypes detected--49.6% and 44.6%, respectively. Over time, the frequency of CRF01_AE subtype increased, the B subtype decreased, and new subtypes of C (4) 2.8%, B' (1) 0.7%, and CRF07_BC (3) 2.2% emerged. The CRF01_AE subtype was commoner in female, Chinese, heterosexuals, and injection drug users whereas B subtype was commoner in male, white, and people with homosexual/bisexual contacts. There was no common source of infection from the analysis except a discernible cluster of Vietnamese injection drug users with the CRF01_AE subtype. The molecular findings did not suggest an epidemiological link between HIV infection in Hong Kong and Mainland China. Hong Kong's longstanding and extensive methadone treatment network may have contributed to the phenomenon.

Adult↗
PubMed2004

Clinicopathological features and prognostic factors of cutaneous melanoma among Hong Kong Chinese.

Cutaneous melanoma is rare among Chinese people. The clinicopathologic features and prognostic factors of 63 Hong Kong ethnic Chinese cases were analysed. We found that the mean age of onset was 65.5 years with a female : male ratio of 1 : 1.33. Forty-two (66.7%) patients had their tumours on their feet. More than 50% had the acral lentiginous histologic subtype. The mean tumour thickness was 5.73 mm with 92.1% (n = 58) having a Clark's level of III or more. Of the tumours, 57.1% were ulcerated. Stage I and II tumours comprised 73% (n = 46) while stage III and IV tumours made up of 26% (n = 17). The 1-, 3- and 5-year survival rates were 75%, 30% and 17%, respectively. Univariate analysis for overall survival showed that advanced clinical staging (stage III and IV), tumour ulceration and thicker tumour (>4 mm) had a significantly poorer prognosis. Multivariate analysis demonstrated that advanced clinical staging was the most decisive prognostic factor followed by tumour ulceration. Our study showed that cutaneous melanoma in Chinese people is a disease predominantly of an older age group with the acral lentiginous histologic type located mainly on the feet. The prognosis depends on clinical staging and ulceration status.

Adolescent↗
PubMed2004

Effects of single nucleotide polymorphisms in the RANTES promoter region in healthy and HIV-infected indigenous Chinese.

We determined the occurrence of the single nucleotide polymorphisms (SNPs) -403A/G and -28C/G in the promoter region of RANTES in 1082 Chinese blood donors from northern and southern China and 249 HIV patients from southern China. Compared to healthy adults, Chinese AIDS patients had a significantly higher frequency of the -403G allele and haplotype I, -403G/-28C (P < 0.05), and a lower frequency of the -403A/A genotype (P < 0.01). Symptomatic patients had a higher frequency of the -28G allele and a lower frequency of the -28C/C genotype (P < or = 0.01). The plasma RANTES level was significantly lower in blood donors homozygous for haplotype I than in those who were homozygous for haplotypes II and III (P < 0.05). The frequency of the -403G allele was found to be higher in Chinese than in indigenous Africans, but lower than in Caucasians, Hispanics, and African Americans. The frequency of the -28G allele was comparable in Chinese and Japanese; this allele is rare in other ethnic groups. Results suggest that -403G may be associated with increased susceptibility to HIV infection, while -28G may be associated with advanced disease progression. The impact of SNPs on HIV infection appears to be unique in Chinese.

Chemokine CCL5↗
PubMed2003

Recovery of touch after median nerve lesion and subsequent repair.

Many techniques have been developed for the evaluation of peripheral nerve function. Consequently, physicians use different techniques in the clinic. This study describes the evaluation of touch after median nerve lesions in the forearm and repair. In order to evaluate touch, 25 patients, aged 11-51 years (mean, 29 years), were evaluated 3-10.5 years (mean, 5 years) after median nerve repair. The evaluation included the moving two-point discrimination test and Semmes-Weinstein monofilaments. We showed that 32% good-excellent results can be obtained with difficult nerve lesions. The results could have been improved if a sensory reeducation regime had been applied.

Adolescent↗
PubMed2003

Determinants of adherence to highly active antiretroviral therapy (HAART) in Chinese HIV/AIDS patients.

OBJECTIVE: Drug adherence is crucial to the success of highly active antiretroviral therapy (HAART) in the treatment of HIV disease. Adherence to HAART and its determinants may, however, differ across HIV/AIDS populations. METHODS: We retrospectively studied drug adherence by self-report in HIV-1 infected Chinese patients who have been on HAART for at least 1 year as at the end of year 2000. HAART is defined as three or more antiretrovirals with at least one protease inhibitor or non-nucleoside analogue reverse transcriptase inhibitor. RESULTS: The last drug adherence level assessed by self-report in 161 Chinese patients were: grade A (100%) - 130, 80.7%; grade B (95-99%) - 25, 15.5%; grade C (90-94%) - three, 1.9% and grade D (< 90%) - three, 1.9%. Patients with full adherence were more likely to have undetectable (< 500 copies/mL) plasma virus level (adjusted OR, 4.22; 95% CI, 1.75-12.33). Patients' demographics, HIV disease status and antiretroviral regimen did not affect adherence. Partial drug adherence was, however, independently associated with the psychosocial factors of missing clinic appointments (adjusted OR, 3.13; 95% CI, 1.23-8.33), forgetfulness (adjusted OR, 4.55; 95% CI, 1.64-12.5) and a busy work life (adjusted OR, 6.67; 95% CI, 1.75-25). CONCLUSION: There were similarities and differences in determinants affecting HAART adherence in Chinese compared with other patients. Psychosocial factors rather than HIV disease or treatment were more important factors in our Chinese patients. The relevance of patient populations and care setting for adherence to HAART shall be further studied.

Adult↗
PubMed2003

Lack of ageing cohort effect among sexually acquired HIV infections in Hong Kong.

We studied HIV rate in different age populations and whether there has been on-going new infections in Hong Kong, by examining the age characteristics and their temporal trend of reported HIV infections. It was found that people in the age group 25-34 were worst hit by the local epidemic. Ageing cohort effect was not apparent for the age pattern of sexually-acquired infections reported from 1987 to 2000, with the annual median ages ranged from 31.5 to 36 years (regression coefficient 0.14, 95% confidence interval -0.14 to 0.42, P = 0.295). Similar temporal age patterns were observed for individual subgroups of homo-/bisexuals, heterosexuals and female heterosexuals. The findings suggested the occurrence of new HIV infections over the years in Hong Kong, despite maintenance of a low prevalence. Albeit capturing largely prevalent infections, reported HIV/AIDS data could be tapped for understanding the evolving epidemic pattern to better evaluate and target current prevention programmes.

Adult↗
PubMed2002

The implication of a reduced-dose hepatitis B vaccination schedule in low risk newborns.

Five hundred and seventy-four babies born to HBsAg negative mothers in Hong Kong received either a regular (5 micro g) or reduced (2.5 micro g) three-dose regimen of recombinant hepatitis B vaccine. A significantly higher anti-HBs positivity rate (>or=10 mIU/ml), geometric mean titer (GMT) and the maintenance of a high anti-HBs level (>or=100 mIU/ml) were observed with the regular-dose regimen. The differences persisted, however, only up to 1 year post-vaccination. Over an 8-year period, only 1% of the vaccinees demonstrated anti-HBc seroconversion and none had become HBsAg positive. The long-term efficacy of the reduced-dose regimen was confirmed, even in an HBV endemic population.

Dose-Response Relationship, Immunologic↗