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Biomedical subjects

M L Wong

Publications and source records attributed to M L Wong.

At least 19 recordsLinked to original sources
PubMed2006

Seroprevalence of HSV-1 and 2 among sex workers attending a sexually transmitted infection clinic in Singapore.

We studied the seroprevalence of herpes simplex virus (HSV)-1 and 2 in sex workers attending a sexually transmitted infection clinic in Singapore and examined their knowledge and attitudes towards HSV infection. A total of 300 participants were recruited. Questionnaires were administered and blood was taken and analysed, using the HerpeSelect 1 and 2 Elisa IgG assays (type-specific serological test). HSV-1 serology was positive in 230 (76.7%), negative in 67 (22.3%) sex workers and indeterminate in three (1.0%) sex workers. HSV-2 serology was positive in 237 (79.0%) and negative in 63 (21.0%) sex workers. On univariate analysis, there was significant association between HSV-2 seropositivity and increasing age, nationality (locals) (P<0.001) and marital status (P<0.01). Adjusting for age, marital status and condom use, HSV-2 prevalence increased significantly with duration of years of practice of sex work. Most of the respondents (86.0%) were aware that HSV could be spread through sex without a condom and about two-thirds of them were aware that HSV could be spread in the absence of symptoms. In conclusion, HSV-2 is a common infection among sex workers in Singapore with the risk increasing with years of practice.

Adult↗
PubMed2006

Pneumocystis jirovecii pneumonia in African miners at autopsy.

SETTING: Deceased miners from South Africa whose cardio-respiratory organs were submitted for autopsy for compensation for occupational lung diseases from 1996 to 2000. OBJECTIVES: 1) To document the incidence of Pneumocystis jirovecii pneumonia (PJP) in autopsied miners; 2) to compare the incidence of PJP over a 5-year period; 3) to record the incidence of concomitant lower respiratory tract infection in a group of PJP-infected deceased miners coming to autopsy from 1996 to 2000; and 4) to describe the accuracy of the in-life diagnosis of PJP in this group. DESIGN: Case series of 328 deceased Black miners with histological evidence of PJP at autopsy. RESULTS: Of the 328 miners with PJP at autopsy, 107 (32.6%) had a concomitant respiratory infection, the most common being cryptococcal pneumonia (46.7%), followed by bacterial pneumonia (34.6%) and pulmonary tuberculosis (13.1%). Overall, Pneumocystis pneumonia was unsuspected prior to death in 89% of cases; however, diagnostic accuracy in life improved from 7% in 1996 to 21% in 2000. CONCLUSION: The high rate of undiagnosed PJP is cause for concern. Clinicians should have a heightened awareness for PJP in Africa, particularly as the disease is treatable at low cost and effective prophylaxis is available.

Autopsy↗
PubMed2006

Tuberculosis at Chris Hani Baragwanath Hospital: an intervention to improve patient referrals to district clinics.

SETTING: A study in 2001 described the process of managing tuberculosis (TB) at Chris Hani Baragwanath hospital, the numbers of patients diagnosed and poor outcomes of referring patients to clinics in the adjacent sub-districts. The present study describes and evaluates an intervention to address the problems. OBJECTIVES: To describe the intervention process (education and referral of TB patients) and the subsequent results over a 2-year period from 2003 to 2005. METHODS: The process of establishing the system and how it was evaluated at district clinics in Johannesburg are described. RESULTS: In the first 2 years of operation, August 2003 to July 2005, 13,138 patients were registered. Extra-pulmonary tuberculosis (EPTB) was diagnosed in 34%. Of the 46% tested for human immunodeficiency virus (HIV), 93% were positive. Successful referral to clinics was achieved for 94% of patients. CONCLUSIONS: Very large numbers of patients are diagnosed with TB at Chris Hani Baragwanath Hospital. A TB care centre has successfully addressed important referral, education and registration requirements for the comprehensive management of TB with links to clinics. It is suggested that this model be applied at other hospitals.

Adolescent↗
PubMed2006

An epidemiological and knowledge, attitudes, beliefs and practices study of sexually transmitted infections in older men.

INTRODUCTION: This study was conducted to determine the disease patterns of sexually transmitted infections (STI) in older men, as well as to gather information on their knowledge, attitudes, beliefs and sexual practices. METHODS: A prospective study was carried out from January to June 2005 in men aged 50 years or older who attended the Department of STI Control clinic. RESULTS: There were 104 men enrolled. The majority (92.3 percent) were Chinese, and 62.5 percent were aged between 50 and 59 years, 25.9 percent between 60 and 69 years, and 11.5 percent aged 70 years or older. The patients were predominantly heterosexual, and had fairly low levels of education--85.6 percent of the patients had received primary or secondary school level of education. Majority (79.8 percent) of the men had been sexually active in the preceding six months, and 37.3 percent had paid sex during that time. 29.8 percent of men reported having taken drugs such as sildenafil (Viagra, Pfizer, New York, NY, USA) or similar drugs such as vardenafil (Levitra, Bayer, Wuppertal, Germany) or tadalafil (Cialis, Eli Lilly, Indianapolis, IN, USA). 56.7 percent of the men had active infections, with non-gonococcal urethritis (15.4 percent), genital warts (12.5 percent) and gonorrhoea (10.6 percent) being the commonest. Generally, condom usage was accepted as an effective way to prevent transmission of STI. However, many of the men surveyed felt that condom usage reduced their sexual pleasure, and 38.5 percent felt that condoms were inconvenient. There were also areas of human immunodeficiency virus (HIV) knowledge that were lacking. Most patients listed the media as their main source of knowledge about STI and HIV. CONCLUSION: Older males attending the clinic remain at significant risk of STI and targeted educational efforts are warranted.

Age Factors↗
PubMed2005

Tuberculosis at Chris Hani Baragwanath Hospital: numbers of patients diagnosed and outcomes of referrals to district clinics.

SETTING: Chris Hani Baragwanath Hospital, in Johannesburg. South Africa is experiencing a serious epidemic of tuberculosis (TB), with a measured rate of 500 cases per 100,000 population. Patients in public hospitals are referred for treatment to district clinics or to specific TB hospitals. OBJECTIVES: To measure numbers of patients diagnosed with TB, and to describe the type of disease and referral outcomes. METHODS: A descriptive study of patients diagnosed with TB in a tertiary hospital. Data in patient files were collected for medical and paediatric patients, and patients were interviewed by researchers who visited clinics to check if referred patients had attended. RESULTS: In the 8-week study period, 1291 patients were diagnosed with TB: 74% had pulmonary disease and 80% of those tested for HIV were positive; 19% died in hospital, and 21% required transfer to a TB hospital. Only half of the patients referred to clinics attended within 2 weeks. CONCLUSIONS: Patients with advanced TB are commonly seen at this hospital. Notifications were an inadequate record and an unacceptable proportion of patients were lost between hospital and clinics. This study has recommended that opportunities for education and discussion must be provided if patients are to reach clinics successfully.

AIDS-Related Opportunistic Infections↗
PubMed2005

Teaching community, occupational and family medicine at the National University of Singapore: past, present and future.

INTRODUCTION: We describe how the curriculum of community, occupational and family medicine (COFM) has evolved in response to social and educational forces and local health needs. Challenges in the teaching of the curriculum are also discussed. CURRICULUM: The COFM Department aims to produce medical undergraduates and graduates with the skills to critically appraise evidence, prevent and manage diseases, and promote health in the community and primary healthcare setting. Its teaching programmes consist of the medical undergraduate programme and the Master of Medicine programmes in Occupational Medicine, Public Health and Family Medicine. The undergraduate modules consist of evidence-based medicine, public health in the community, disease prevention and control, occupational medicine practice, health promotion and behaviour, and communication with patients. The university's first completely online module on SARS was jointly implemented by the Department and the Centre for Instructional Technology for the entire student population last year. The COFM curriculum has shifted from giving students factual information through lectures to developing students' critical thinking and problem-solving skills through small group teaching, case studies and community health projects. Innovative assessment methods such as open-book examinations; objective structured communication stations with simulated patients; and evaluation of students' participation in group work are used to assess students' skills in problem-solving, communication and teamwork respectively. CONCLUSION: While the Department has made significant progress in developing a relevant and updated curriculum based on appropriate learning and assessment approaches, it will strive to do more to develop students' critical thinking skills by using newer approaches.

Community Medicine↗
PubMed2004

Clinical course after stopping lamivudine in chronic hepatitis B patients with lamivudine-resistant mutants.

BACKGROUND: The efficacy of lamivudine therapy in chronic hepatitis B is well established. However, drug-resistant YMDD mutants emerge with extended therapy. This may result in the resurgence of viral replication, the return of hepatitis and histological deterioration. AIM: To study the safety of stopping lamivudine when the drug is no longer effective. METHODS: In the 5-year Asian Lamivudine Study, 34 patients from a single centre were included in this study. They had harboured YMDD mutants for at least 2 years. Lamivudine was discontinued and they were followed up at regular intervals. Clinical symptoms, liver biochemistry and viral serology were monitored. RESULTS: In a median follow-up of 20 months after stopping lamivudine (range, 7-39 months), 20 of the 34 patients (58.8%) had elevated alanine aminotransferase (ALT), 13 patients (38.2%) had elevated ALT one to five times the upper limit of normal and seven patients (20.6%) had an ALT flare (ALT more than five times the upper limit of normal with detectable hepatitis B virus DNA). There was no liver decompensation. ALT flare could be predicted by ALT over twice the upper limit of normal at the time of stopping lamivudine (P = 0.037). CONCLUSIONS: It is relatively safe to stop lamivudine after YMDD mutants have emerged. ALT levels greater than or equal to twice the upper limit of normal at the time of stopping lamivudine have a higher risk for ALT flare.

Adult↗
PubMed2004

Willingness to donate blood samples for genetic research: a survey from a community in Singapore.

Studies on the public's willingness to donate blood specimens for genetic research are few and are conducted mainly among Western countries. Little is known about the Asian community's willingness to participate in genetic research. A community-based survey was conducted on 548 adult Singaporeans to examine their willingness to donate blood samples for genetic research and its associated factors. The response rate was 70.3%. About 49.3% (95% CI, 45.1-53.5%) were willing to donate blood for genetic research. In the multivariable Cox regression analysis, willingness was significantly associated with belief in the benefits of genetic research; intention to participate in government studies; having no fear of pain, blood, injections, and needles; and non-concern about the loss of confidentiality. Reasons against donating blood were fear of pain, blood, injections, and needles (38.1%); no self-benefits (24.8%); fear of finding out about having a disease (22.3%); fear of discrimination (18.7%); and concerns about weakness (15.1%) and weight gain (9.4%). Public education programs to promote participation in genetic research should stress its benefits and address people's fears and concerns.

Adult↗
PubMed2004

Genotype C hepatitis B virus infection is associated with an increased risk of hepatocellular carcinoma.

BACKGROUND: Identification of risk factors for the development of hepatocellular carcinoma (HCC) is important for HCC surveillance in chronic hepatitis B virus (HBV) infection. Our aim was to study the independent risk factors and effect of HBV genotypes on HCC development in a prospective longitudinal cohort of chronic hepatitis B patients. PATIENTS AND METHODS: Chronic hepatitis B patients recruited since 1997 were prospectively followed up for the development of HCC. HCC was diagnosed by a combination of alpha fetoprotein, imaging, and histology. Liver cirrhosis was defined as ultrasonic features of cirrhosis together with hypersplenism, ascites, varices, and/or encephalopathy. RESULTS: In total, 426 patients were followed up for 1664 person years; median 225 (range 12-295) weeks. Forty nine (11%) patients had underlying clinical liver cirrhosis. A total of 242 (57%) and 179 (42%) patients had HBV genotypes C and B, respectively. Twenty five patients developed HCC in a median follow up of 121 (range 14-236) weeks. The overall incidence of HCC was 1502 cases per 100 000 person years. On multivariate analysis, clinical liver cirrhosis and HBV genotype C infection were independently associated with HCC development, with an adjusted relative risk of 10.24 (95% confidence interval (CI) 4.39-23.89; p<0.001) and 2.84 (95% CI 1.05-7.72; p = 0.040), respectively. Patient age, sex, hepatitis B e antigen (HBeAg) status, alanine aminotransferase (ALT) levels, and basal core promoter mutations did not predict HCC development. Patients infected with HBV genotype C tended to have persistently positive HBeAg or fluctuating HBeAg status and higher ALT levels during the follow up period. CONCLUSION: Genotype C HBV infection is an independent risk factor for HCC development in addition to liver cirrhosis.

Adolescent↗
PubMed2004

Bupropion in the management of apathy.

We report on three males with prominent apathy as part of the symptom complex of depression or organic brain disease. Significant clinical responses were observed following treatment with bupropion, an antidepressant with dopamine (DA) reuptake activity. We present clinical evidence in support of the hypothesis that remission in these patients occurred as a consequence of bupropion-induced increases in central DA neurotransmission.

Adult↗
PubMed2003

NOD2/CARD15 gene polymorphisms and Crohn's disease in the Chinese population.

BACKGROUND: Crohn's disease affects people world-wide, but the incidence in Asia is lower than in Western countries. This difference may be due to genetic and/or environmental factors. Three single nucleotide polymorphisms (SNPs) of the NOD2/CARD15 gene have been identified to be independently associated with the development of Crohn's disease in Caucasians. Whether these SNPs are involved in the pathogenesis of Crohn's disease in the Chinese population is unknown. AIM: To determine if NOD2/CARD15 gene polymorphisms are found in Chinese patients with Crohn's disease. METHODS: Sixty-five consecutive Chinese Crohn's disease patients had genotyping performed using sequence-specific PCR directed against the wild-type and the Arg702Trp, Gly908Arg and 3020insC variants of the NOD2/CARD15 gene. Controls consisted of 63 patients with ulcerative colitis and 70 patients with dyspepsia. RESULTS: None of the patients with Crohn's disease had heterozygous or homozygous SNP variants. Similarly none of the ulcerative colitis or dyspeptic controls had these SNPs. CONCLUSION: The three previously described SNPs associated with the development of Crohn's disease in Caucasians are not found in Chinese patients with Crohn's disease.

Adolescent↗
PubMed2003

Cloning and sequencing of complete cDNA of Japanese encephalitis virus YL strain in Taiwan.

We determined the complete nucleotide sequence of the YL strain of Japanese encephalitis virus and its amino acid sequence was deduced. Our results displayed that the genome of YL strain contained a single open reading frame of 10,296 nucleotides (nts) which was flanked by untranslated region (UTR) containing 95 bases at the 5'-end and 586 bases at the 3'-end, respectively. Comparison of sequences showed that the overall amino acid sequence and 3' UTR of YL were similar to those of the virulent strain JaGAr0l. However, some significant amino acid differences of viral envelope (E) protein were observed between YL and JaGAr01; the amino acid sequence of E protein in YL strain possessed RGG(387-389) tripeptide instead of RGD(387-389) in JaGAr01 and in other strains; and another amino acid is K(138) in YL, not E(138) found in others. These differences suggested that the YL strain impairs in viral attachment to the cell surface and loses neuroinvasiveness, and therefore this strain was used as a live attenuated vaccine.

3' Untranslated Regions↗
PubMed2003

The use of complementary and alternative medicine by asthma patients.

BACKGROUND: Use of complementary and alternative medicines (CAM) by asthmatic patients is increasing. Data on the prevalence of CAM use in asthma are limited, and the motivation for patients to seek CAM therapy is uncertain. AIM: To determine the prevalence and pattern of use of complementary therapies in adults treated for asthma in primary care in Singapore, and the demographic and clinical factors associated with their use. DESIGN: Cross-sectional study. SETTING: Five primary care clinics in Singapore. METHODS: Adult patients with asthma (n = 802) received a structured questionnaire interview and clinical assessment that included demographic and clinical variables (clinical status, patient's knowledge, self-care and healthcare-seeking behaviour, and spirometric measurements) and detailed information on CAM use in the past one year. RESULTS: CAM use in the past year was reported by 27.2%, including animal food products (12.3%), herbs (10.3%), herbal-based proprietary medicines (3.2%), and acupuncture or reflexology (1%). The use of CAM was significantly associated with Chinese ethnicity, longer disease duration, moderate and severe persistent asthma, FEV(1)/FVC < 80%, lack of positive response to treatment in the past year, higher patient knowledge score, and multiple sources of care providers. DISCUSSION: The use of CAM is highly prevalent in Asian patients treated for asthma in primary care, and is associated with cultural and clinical factors reflecting a need to improve care.

Adult↗
PubMed2003

Awareness of glaucoma, and health beliefs of patients suffering primary acute angle closure.

AIM: To evaluate the factors associated with lack of awareness of glaucoma and late presentation to the doctor in Singapore Chinese patients with acute angle closure (AAC) METHODS: A prospective, hospital based case series of 105 patients aged 35 years and above who presented with a first attack of AAC in a tertiary hospital in Singapore was conducted. A research assistant interviewed all patients face to face in clinic and recorded demographic factors, awareness of glaucoma, and subjective barriers to seeing a doctor. The time from onset of symptoms to presentation at the clinic was noted. RESULTS: Overall, 22.9% of patients had heard of glaucoma. The multivariate adjusted odds ratio (OR) of unawareness of glaucoma in older people (> 60 years) was 1.5 (95% confidence interval (CI) 0.5 to 4.6), 3.2 (95% CI 1.1 to 9.2) for adults who were not working, and 13.8 (95% CI 1.3 to 146.7) for patients who had less than a pre-university education. A significant proportion (31.7%) of patients presented to the doctor 24 hours or more after symptoms occurred. In a multiple logistic regression model, the adjusted OR of late presentation was 8.5 (95% CI 1.04 to 69.5) if there was no car access, 5.0 (95% CI 1.0 to 24.6) if the patients spoke Chinese, and 3.3 (95% CI 0.9 to 11.9) if there was nobody to accompany to hospital. CONCLUSION: Glaucoma awareness among patients suffering AAC was not high. Lack of awareness was associated with increasing age, lack of formal education, and unemployment. A significant proportion of patients seek medical attention late. Risk factors for late presentation include lack of car access, nobody to accompany the patient, and speaking the Chinese language primarily. Health education programmes may help increase the knowledge and awareness of glaucoma.

Age Factors↗
PubMed2003

Social and behavioural factors associated with condom use among direct sex workers in Siem Reap, Cambodia.

OBJECTIVES: To determine the social and behavioural factors associated with condom use among direct sex workers in Siem Reap, Cambodia. METHODS: Using a structured behavioural questionnaire, interviews were conducted with 140 direct sex workers attending a health centre in Siem Reap for HIV screening. RESULTS: Consistent condom use with their clients was reported by 78% of sex workers compared to only 20% with their non-paying partners. Consistent condom use with clients was significantly higher among higher income than lower income sex workers (adjusted prevalence ratio: 1.91, 95% CI: 1.15 to 3.18) and those with good rather than poor negotiation skills (adjusted prevalence ratio: 1.51, 95% CI: 1.01 to 2.26), after adjustment for age, educational level, marital status, number of sexual encounters per week, and knowledge of AIDS/HIV and sexually transmitted infections. The most frequently reported reason for not using condoms with clients was not being able to persuade them (66.7%), while for non-paying partners, the reason was that they loved them (60.0%). CONCLUSION: To complement the government's current programme of client education, 100% condom policy and brothel administrative measures, additional strategies to increase condom use among clients and non-paying partners should be directed at (i) the social policy and community levels to address sex workers' economic and cultural barriers to condom use, and (ii) personal level empowerment through developing sex workers' condom negotiation skills.

Adult↗
PubMed2003

Erectile dysfunction in Singapore: prevalence and its associated factors--a population-based study.

PURPOSE: To study the prevalence of erectile dysfunction (ED) in Singapore males aged 30 and above and its association with demographic, medical and other risk factors. METHODOLOGY: A population based cross sectional study of 729 men aged 30 and above in Singapore was conducted using the abridged, five-item version of the International Index of Erectile Function (IIEF-5). Presence of erectile dysfunction was defined as IIEF-5 score of less than 21. Erectile dysfunction was further categorised into mild (IIEF-5: 16-20), moderate (IIEF-5: 11-15) and severe (IIEF-5: <11). A logistic regression model was used to identify significant independent risk factors for ED. RESULTS: Overall, 51.3% of respondents (n=374) reported some degree of erectile dysfunction. Of these, 23.2% have mild ED, 8.8% have moderate ED and 19.3% had severe ED. The prevalence of ED increased from 42.8% for men in their forties to 77.4% in their sixties. The prevalence of severe ED increased from 9.1% in men in their forties to 43.5% in their sixties and 77.0% in those aged 70 and above. Age above 50 years is the single most significant risk factor on multivariate analysis when adjusted for all confounding factors. Other important risk factors include Indian ethnic group, lower household income, physical inactivity, diabetes mellitus and cardiac diseases. CONCLUSION: Erectile dysfunction is common amongst Singaporean men. Age is the single most important physiologic factor affecting erectile function. The prevalence and severity increased significantly with age after 50 years old. With an ageing population, erectile dysfunction may become a significant health problem. Health care providers should plan their resources accordingly.

Adult↗
PubMed2002

Relationship of clinical and virological factors with hepatitis activity in hepatitis B e antigen-negative chronic hepatitis B virus-infected patients.

To investigate the factors associated with active disease among hepatitis B surface antigen (HBsAg) positive/hepatitis B e antigen (HBeAg)-negative chronic hepatitis B virus (HBV) infection we studied chronic HBV infected patients who had undetectable HBeAg at the first visit. HBV DNA was determined by the cross-linking assay (NAXCOR) and polymerase chain reaction (PCR). Mutations in the core promoter and precore regions and viral genotypes were studied. Clinical outcome of these patients were followed and categorized as: (i) relapse (ALT > 200 IU/L or three times the previous levels); (ii) active hepatitis (elevated ALT < 200 IU/L with concomitant detectable HBV DNA); or (iii) remission. A total of eighty-five patients were followed up for 5.5 +/- 1.0 years. At first visit, 31 (36.5%) patients had elevated ALT levels, 12 (14.1%) had measurable HBV DNA by the cross-linking assay and 26 (30.6%) by PCR. Sixteen (18.8%) patients had hepatitis relapse, 13 (15.3%) had active hepatitis, and 56 (65.9%) remained in remission. Core promoter and precore stop codon mutants were found in 27 and 12 patients, respectively. Eleven and 20 had genotype B and C HBV, respectively. Initial elevated ALT and detectable HBV DNA were associated with active liver disease. Patient demographics, viral mutants or genotypes failed to predict disease activity. Hence, serum ALT and HBV DNA levels offer the best prediction of natural course of HBeAg-negative chronic HBV infection.

Adult↗