Acute HIV infection in Singapore: predominance of men who have sex with men

INTRODUCTION

The incidence of human immunodeficiency virus (HIV) infection in Singapore is on the rise. We aimed to study the clinical epidemiology of acute HIV infection in Singapore.

METHODS

All patients that fulfilled the criteria for definite and probable acute HIV infection were prospectively identified from January 1, 2003 to June 30, 2006. Demographic, clinical and laboratory data were recorded.

RESULTS

A total of 16 out of 34 patients had definite acute HIV infection, and 68 percent of the entire cohort comprised men who have sex with men (MSM). Ten percent of the patients were co-infected with hepatitis B and C viruses, while 27 percent were infected with syphilis. Signs and symptoms were nonspecific, with fever, rash and diarrhoea being the three most common symptoms. Only 35 percent of the patients required hospitalisation.

CONCLUSION

Men who have sex with men account for the majority of patients with acute HIV infections in Singapore, many of them also being co-infected with syphilis. Safer sex campaign among MSM should be implemented or intensified.

Analysis and modeling of nano-crystalline silicon TFTs on flexible substrate with mechanical strain

The gap state density of nano-crystalline silicon active layers on a flexible substrate was redistributed with mechanical bending. The weak or broken bonds may contribute to the redistribution of trap states. During mechanical strain, the deep states redistributed in a Gaussian distribution, and are dissimilar to ordinary acceptor-like deep states, which manifest with exponential distributions. We conclude that the gap state density with TCAD modeling under mechanical strain is the fundamental reliability issue for the development of flexible electronics.

Cellular dosimetry and microdosimetry for internal electron emitters

Radiobiological descriptions of cellular dosimetry and microdosimetry require both radiation dose and radiation quality. The lineal energy, defined as a ratio of the energy deposition by a particle in the biological target and the mean chord length of this target, is generally adopted to characterise the radiation quality. Most microdosimetry applications assume that the cell nucleus is the target region. Therefore, the lineal energy is obtained for the source (S) to target (T) geometry, T ← S, where S = cell surface, cytoplasm, cell nucleus and T = cell nucleus. The definition of lineal energy is based on the approximation that the particle mean pathlength is equal to target mean chord length. This approximation is valid for crossers of external irradiations. In the case of starters, insiders and stoppers of internal sources, particle pathlengths are always shorter than target chord lengths. Thus, the lineal energy does not reflect the specific energy deposition along particle path. In the present work, the specific energy deposition in a target is calculated using three distance parameters, i.e. target mean chord length, particle mean pathlength in the target and particle individual pathlength in the target. Monte Carlo calculations are performed for electrons of various energies and cells of different sizes. Results are analysed and discussed.

Optimal design of a microcavity organic laser device under electrical pumping

The quality factor of microcavity organic lasers, designed for operation under electric pumping, has been numerically investigated. The microcavity structure consists of an organic light emitting diode set in between multilayer dielectric mirrors centered for an emission at 620 nm. In order to optimize the quality factor, different parameters have been studied: the impact of high and low index materials used for the multilayer mirrors, the role of a spacer inserted in between the mirrors to obtain an extended cavity, and the effect of an absorbing electrode made of metallic or transparent conductive oxide layer. The results of our different optimizations have shown a quality factor (Q) as high as 15,000.

Mosaic supernumerary r(1)(p13.2q23.3) in a 10-year-old girl with epilepsy facial asymmetry psychomotor retardation kyphoscoliosis dermatofibrosarcoma and multiple exostoses

We report molecular cytogenetic characterization of mosaic supernumerary r(1)(p13.2q23.3) in a 10-year-old girl with epilepsy, facial asymmetry, psychomotor retardation, kyphoscoliosis, dermatofibrosarcoma and multiple exostoses. The supernumerary r(1) is associated with gene dosage increase of CHRNB2, ADAR and KCNJ10 in the pericentromeric area of 1q, and a breakpoint within CTTNBP2NL at 1p13.2. We speculate that the gene dosage increase of CHRNB2, ADAR and KCNJ10 is most likely responsible for epilepsy, and the breakpoint at 1p13.2 in the supernumerary r(1) is most likely responsible for the development of multiple exostoses and osteochondroma in this patient.

Interrelationship between exposure to PCDD/Fs and hypertension in metabolic syndrome in Taiwanese living near a highly contaminated area

Metabolic syndrome (MetS) consists of a constellation of metabolic abnormalities that confer increased risk of cardiovascular disease. There is a positive correlation between exposure to persistent organic pollutants and MetS. We examine the association between PCDD/Fs and MetS components in 1490 non-diabetic persons living near a highly dioxin-contaminated area. We used factor analysis, with a set of core variables considered central features of MetS and PCDD/Fs, to group similar risk factors. Serum PCDD/Fs were positively and significantly correlated with the number of MetS components. Four risk factors-lipidemia, blood pressure, body size, and glycemia-accounted for 72.6% of the variance in the 10 core factors, and PCDD/Fs were linked to MetS through shared correlations with high blood pressure. After adjusting for confounding factors, we found that diastolic blood pressure (β=0.018; p=0.006), glucose (β=0.013; p=0.046), and waist circumference (β=0.721; p=0.042) significantly increased with increasing serum PCDD/F levels. We found significant trends for associations between metabolic syndrome and serum low-chlorinated PCDD/Fs. The highest quintiles of 2,3,4,7,8-PeCDF, 1,2,3,6,7,8-HxCDF and 2,3,7,8-TCDD had the top three adjusted ORs (95% CI) of 3.5 (1.9-6.3), 2.9 (1.7-4.9) and 2.8 (1.6-4.9), respectively. We also found a slight monotonic relationship between serum PCDD/Fs and the prevalence of MetS, especially when the serum dioxin level was higher than 25.4pg WHO(98)-TEQ(DF)g(-1) lipid (the fourth Quintile). We hypothesize that high-dose exposure to PCDD/Fs is a blood pressure-related factor that raises MetS risk.

Association between alcohol consumption and diabetic retinopathy and visual acuity-the AdRem Study

AIMS

We investigated the association between alcohol consumption and diabetic retinopathy and deterioration of visual acuity in individuals with Type 2 diabetes.

METHODS

We conducted a cohort analysis of 1239 participants with Type 2 diabetes aged 55-81 years enrolled in the AdRem study, a sub-study of the Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation (ADVANCE) trial. Current and past consumption of wine, spirits and beer was measured by self-report. Moderate and heavy alcohol consumption was defined as 1-14 and >14 drinks/week, respectively. Diabetic retinopathy, measured by mydriatic stereoscopic seven-field retinal photography, was defined by a 2-step progression in the Early Treatment of Diabetic Retinopathy Study (ETDRS) score or the presence of any retinal vascular lesions. Deterioration of visual acuity was defined by a decrease of two lines in best vision in either eye, measured corrected, or through a pinhole using a Snellen chart.

RESULTS

In a mean follow-up of 5.5 years, we identified 182 participants with a 2-step progression in the ETDRS score, 640 participants with the presence of any retinal vascular lesions and 693 participants with a deterioration of visual acuity. Current moderate consumption of alcohol, compared with no current consumption, was not associated with presence or progression of diabetic retinopathy; however, it was associated with higher risk of deterioration of visual acuity (multivariable-adjusted OR 1.83; 95% CI 1.34-2.48; P<0.001).

CONCLUSIONS

Alcohol consumption is associated with increased risk of deterioration of visual acuity, but not with retinopathy in individuals with Type 2 diabetes.

Prevalence and characteristics of ertapenem-nonsusceptible Escherichia coli in a Taiwanese university hospital, 1999 to 2007

The present study was conducted to investigate the prevalence and characteristics of ertapenem-nonsusceptible (ETP-NS) Escherichia coli in a Taiwanese university. A total of 9,722 isolates collected in 1999, 2003, 2005, and 2007 were examined. Overall, 1.0% of all isolates from 66 patients were interpreted as ETP-NS on the basis of the disk diffusion test result. Most of these isolates were clonally unrelated and showed low-level ertapenem resistance, the production of CMY-2 cephalosporinase (86.4%), and decreased expression of the OmpF (97.0%) and/or OmpC (56.1%) porins. No carbapenemase was detected. The decreased porin expression was associated with disruptions of ompF or ompC in only about one-third of the ETP-NS isolates. During the study period, the prevalence of ETP-NS strains increased from 0.1 to 1.7%, accompanying an increase (0.8 to 17.6%) in the prevalence of CMY-2 producers. Coexistent or pre-existing clonally related ertapenem-susceptible (ETP-S) E. coli isolates were identified in 47.0% of all case patients, and almost all of the ETP-S isolates had the same β-lactamases as the ETP-NS isolates. Our study results suggest the restricted use of extended-spectrum cephalosporins to hinder the emergence and prevalence of carbapenem resistance in E. coli, which may arise by the accumulation of multiple resistance determinants.

Adenosine Triphosphate Content of Selenastrum capricornutum

The adenosine triphosphate content of Selenastrum capricornutum was maintained within 1.4 to 3.4 mug of adenosine triphosphate/mg (dry weight) of living biomass at different growth stages in media of different phosphorus concentrations.

Validation of Self-administrated Questionnaire for Psychiatric Disorders in Patients with Functional Dyspepsia

Introduction

Psychiatric comorbidity is common in patients with functional dyspepsia (FD) but a good screening tool for psychiatric disorders in gastrointestinal clinical practice is lacking.

Aims

1) Evaluate the performance and optimal cut-off of 12-item General Health Questionnaire (GHQ-12) as a screening tool for psychiatric disorders in FD patients; 2) Compare health-related quality of life (HRQoL) in FD patients with and without psychiatric comorbidities.

Methods

Consecutive patients fulfilling Rome III criteria for FD without medical co-morbidities and gastroesophageal reflux disease were recruited in a gastroenterology clinic. The followings were conducted at 4 weeks after index oesophagogastroduodenoscopy: self-administrated questionnaires on socio-demographics, dyspeptic symptom severity (4-point Likert scale), GHQ-12, and 36-item short-form health survey (SF-36). Psychiatric disorders were diagnosed with Structured Clinical Interview for DSM-IV Axis I Disorders (SCID) by a trained psychiatrist, which served as reference standard.

Results

55 patients underwent psychiatrist-conducted interview and questionnaire assessment. 27 (49.1%) had current psychiatric disorders as determined by SCID (anxiety disorders: 38.2%, depressive disorders: 16.4%). Receiver operating characteristic curve analysis of GHQ-12 revealed an area under curve of 0.825 (95%CI: 0.698-0.914). Cut-off of GHQ-12 at ≥3 gave a sensitivity of 63.0% (95%CI = 42.4-80.6%) and specificity of 92.9% (95%CI = 76.5%-98.9%). Subjects with co-existing psychiatric disorders scored significantly lower in multiple domains of SF-36 (mental component summary, general health, vitality and mental health). By multivariate linear regression analysis, current psychiatric morbidities (Beta = -0.396, p = 0.002) and family history of psychiatric illness (Beta = -0.299, p = 0.015) were independent risk factors for poorer mental component summary in SF-36, while dyspepsia severity was the only independent risk factor for poorer physical component summary (Beta = -0.332, p = 0.027).

Conclusions

Concomitant psychiatric disorders adversely affect HRQoL in FD patients. The use of GHQ-12 as a reliable screening tool for psychiatric disorders allows early intervention and may improve clinical outcomes of these patients.

Plasma vitamin C and tocotrienols changes in response to dietary supplementation among young male adults

BACKGROUND AND AIMS

Intake of the antioxidant vitamins C and E lowers the oxidative stress. The study aimed to determine plasma concentrations of vitamin C and tocotrienols after supplementation of both vitamins in young male adults.

MATERIALS AND METHODS

A total of 64 police recruits were randomly assigned to one of these groups: (a) 500 mg vitamin C (Vitamin C), (b) 200 mg Tocovid (Tocotrienol), (c) combination of 500 mg vitamin C and 200 mg Tocovid (Combination) or (d) placebo (Placebo) for eight-weeks of supplementation followed by six-week washout period.

RESULTS

In Combination group, mean plasma vitamin C concentration significantly increased from baseline 2.86 +/- 1.19 mg/L to 10.37 +/- 1.29 mg/L and 15.63 +/- 1.27 mg/L after four- and eight-week supplementation, respectively. The corresponding figures for alpha-, delta- and gamma-tocotrienols were 9.9 +/- 2.5 ng/ml to 104.1 +/- 19.8 ng/ml and 112.8 +/- 38.0 ng/ml; 2.5 +/- 0.9 ng/ml to 29.9 +/- 7.0 ng/ml and 17.9 +/- 4.7 ng/ml; 19.2 +/- 3.1 ng/ml to 75.2 +/- 24.1 ng/ml and 161.7 +/- 49.9 ng/ml, respectively. In Vitamin C group, plasma vitamin C concentrations were significantly increased. Conversely, concentration of plasma vitamin C in Tocotrienol group increased from baseline of 2.72 +/- 0.20 mg/L to 6.80 +/- 0.63 mg/L and 8.9 +/- 0.77 mg/L respectively. Plasma concentrations of alpha-, delta- and gamma-tocotrienols in this group were significantly elevated. After 6-week washout period, all the elevated concentrations returned to basal levels.

CONCLUSION

The study showed a good bioavailability of these vitamins and increment due to supplementation.

Sex hormone-binding globulin and risk of type 2 diabetes in women and men

BACKGROUND

Circulating sex hormone-binding globulin levels are inversely associated with insulin resistance, but whether these levels can predict the risk of developing type 2 diabetes is uncertain.

METHODS

We performed a nested case-control study of postmenopausal women in the Women's Health Study who were not using hormone therapy (359 with newly diagnosed type 2 diabetes and 359 controls). Plasma levels of sex hormone-binding globulin were measured; two polymorphisms of the gene encoding sex hormone-binding globulin, SHBG, that were robustly associated with the protein levels were genotyped and applied in mendelian randomization analyses. We then conducted a replication study in an independent cohort of men from the Physicians' Health Study II (170 with newly diagnosed type 2 diabetes and 170 controls).

RESULTS

Among women, higher plasma levels of sex hormone-binding globulin were prospectively associated with a lower risk of type 2 diabetes: multivariable odds ratios were 1.00 for the first (lowest) quartile of plasma levels, 0.16 (95% confidence interval [CI], 0.08 to 0.33) for the second quartile, 0.04 (95% CI, 0.01 to 0.12) for the third quartile, and 0.09 (95% CI, 0.03 to 0.21) for the fourth (highest) quartile (P<0.001 for trend). These prospective associations were replicated among men (odds ratio for the highest quartile of plasma levels vs. the lowest quartile, 0.10; 95% CI, 0.03 to 0.36; P<0.001 for trend). As compared with homozygotes of the respective wild-type allele, carriers of a variant allele of the SHBG single-nucleotide polymorphism (SNP) rs6259 had 10% higher sex hormone-binding globulin levels (P=0.005), and carriers of an rs6257 variant had 10% lower plasma levels (P=0.004); variants of both SNPs were also associated with a risk of type 2 diabetes in directions corresponding to their associated sex hormone-binding globulin levels. In mendelian randomization analyses, the predicted odds ratio of type 2 diabetes per standard-deviation increase in the plasma level of sex hormone-binding globulin was 0.28 (95% CI, 0.13 to 0.58) among women and 0.29 (95% CI, 0.15 to 0.58) among men, a finding that suggests that sex hormone-binding globulin may have a causal role in the risk of type 2 diabetes.

CONCLUSIONS

Low circulating levels of sex hormone-binding globulin are a strong predictor of the risk of type 2 diabetes in women and men. The clinical usefulness of both SHBG genotypes and plasma levels in stratification and intervention for the risk of type 2 diabetes warrants further examination.

Association of C-reactive protein with type 2 diabetes: prospective analysis and meta-analysis

AIMS/HYPOTHESIS

We examined the association between serum C-reactive protein (CRP) and incident diabetes in a prospective study, and added these data to a literature-based meta-analysis to explore potential sources of heterogeneity between studies.

METHODS

We analysed a case-control study nested within the European Prospective Investigation of Cancer (EPIC)-Norfolk cohort, including 293 incident diabetes cases and 708 controls. We combined 16 published studies on CRP and incident diabetes in a random-effect meta-analysis.

RESULTS

In the EPIC-Norfolk cohort, serum CRP was associated with a higher risk of diabetes after adjusting for age, sex, BMI, family history of diabetes, smoking and physical activity (OR 1.49, comparing the extreme thirds of CRP distribution [95% CI 1.03-2.15], p = 0.03). However, the association was completely attenuated after further adjustment for WHR, serum gamma-glutamyltransferase and serum adiponectin (OR 1.00; 95% CI 0.66-1.51, p = 1.0). In a meta-analysis of 16 published studies with 3,920 incident diabetes cases and 24,914 controls, the RR was 1.72 (95% CI 1.54-1.92), comparing the extreme thirds of CRP distribution, with substantial heterogeneity between studies (I (2) = 52.8%, p = 0.007).

CONCLUSIONS/INTERPRETATION

Initial evidence of association between CRP and incident diabetes was confounded by central adiposity, markers of liver dysfunction and adiponectin in the primary analysis. Despite an overall positive association in the meta-analysis, considerable heterogeneity existed between studies. The degree of adjustment for central adiposity and baseline glycaemia explained some of this heterogeneity and suggests that CRP may not be an independent risk factor for type 2 diabetes.

Primary drug resistance and transmission analysis of HIV-1 in acute and recent drug-naïve seroconverters in Singapore

OBJECTIVES

The aim of the study was to elucidate primary drug resistance and transmission of HIV-1 in acute and recent drug-naïve seroconverters in Singapore.

METHODS

Acute and recent HIV-1 seroconverters were enrolled in the study. The HIV-1 polymerase (pol) gene was sequenced and used for genotypic drug resistance analysis and phylogenetic analysis. HIV-1 transmission clusters were inferred from phylogenetic clustering analysis.

RESULTS

Of the 60 subjects analysed, 95% were men, and 73.3% were men who have sex with men (MSM). Six HIV-1 subtypes were identified, including CRF01_AE (46.7%), subtypes B (30%), B' (15%) and G (1.7%), CRF33_01B (1.7%) and CRF34_01B (5%). Primary genotypic resistance was detected in only one (1.7%) subtype B variant. Thirty-one patients (51.7%) were phylogenetically clustered, of whom 90% reported having local risk exposure, compared with 59% of the patients who were not phylogenetically clustered [odds ratio (OR) 6.35, 95% confidence interval (CI) 1.65-23.95]. MSM (OR 5.63, 95% CI 1.17-27.15), high viral load (OR 4.28, 95% CI 1.37-13.36) and young age (OR 0.92, 95% CI 0.85-0.99) were independently associated with clustered individuals.

CONCLUSIONS

In Singapore, HIV-1 primary resistance is insignificant; individuals with seroconversion account for about half of onward transmission among recently infected seroconverters. MSM, high viral load and young age are factors that facilitate transmission. Early detection of these individuals is of paramount importance for the prevention of HIV-1 transmission.

Validation of medium-pressure UV disinfection reactors by Lagrangian actinometry using dyed microspheres

Lagrangian actinometry (LA) has been demonstrated to represent an alternative to conventional biodosimetry for validation of ultraviolet (UV) disinfection systems used in drinking water treatment. However, previous applications of LA for this purpose have all involved monochromatic (lambda = 254 nm) UV reactor systems. To address this issue, dyed microspheres (DMS) were applied for quantification of dose distribution delivery by field-scale UV reactor systems based on medium-pressure Hg lamp (MP) technology. These MP reactor systems are characterized by polychromatic output. Dose distribution estimates developed by LA for these reactors were reported as equivalent 254 nm distributions. When combined with the UV(254) dose-response behavior for challenge organisms used in simultaneous or parallel biodosimetry experiments, the dose distribution estimates developed from the microspheres yielded estimates of challenge organism inactivation that were in agreement with measured values. For one of the reactors tested, biodosimetry tests were conducted with two challenge organisms that had different UV dose-response behavior; UV dose distribution estimates from LA yielded predictions of microbial inactivation that were in agreement with measured inactivation responses for both challenge organisms for all test conditions. It is likely that the agreement between LA results and biodosimetry data was related, in part, to the agreement between the action spectra of the microspheres and the challenge organisms. Because LA yields a measure of the UV dose distribution delivered by a reactor, the information from LA assays will eliminate many sources of uncertainty in the design and operation of UV systems, thereby allowing for implementation of UV reactor systems that are less expensive than their predecessors, yet more reliable.

Relation of genetic variation in the gene coding for C-reactive protein with its plasma protein concentrations: findings from the Women's Health Initiative Observational Cohort

BACKGROUND

Although common genetic variants of the CRP gene (C-reactive protein, pentraxin related) have been associated with plasma concentrations of high-sensitivity CRP (hsCRP) in several cohorts of European Americans, relatively few studies have comprehensively assessed this association in well-characterized multiethnic populations.

METHODS

In a case-control study of diabetes nested in the Women's Health Initiative Observational Cohort, we comprehensively evaluated the association of genetic variation in CRP with plasma hsCRP concentrations. Thirteen haplotype-tagging single-nucleotide polymorphisms (tSNPs) were identified and subsequently genotyped in 3782 postmenopausal women.

RESULTS

The allele frequencies for these tSNPs and the haplotype blocks defined by these tSNPs varied significantly by ethnic group (P < 0.0001). Consistent with prior studies of whites, rs3093068, rs1130864, and rs1417938 were significantly associated with higher hsCRP concentrations (geometric-mean increase per minor-allele change, 1.20-1.25 mg/L), and rs1205 and rs1800947 were significantly associated with lower hsCRP values (decrease of 1.28-1.48 mg/L). The associations with rs3093068 and rs1205 appeared to be stronger in Asians/Pacific Islanders than in whites (geometric-mean increase, 1.65 mg/L vs 1.25 mg/L, respectively). Minor alleles at rs3093075 and rs3093059 were associated with substantially increased hsCRP concentrations, whereas rs1800947 was associated with lower hsCRP values. All haplotype-based association results tended to be consistent with the associations seen with single CRP SNPs.

CONCLUSIONS

Our large multiethnic case-control study of postmenopausal women provides evidence that common genetic variants in the CRP gene are substantially associated with plasma hsCRP concentrations in this case-control subcohort. The data also suggest ethnic variations in these associations.

Ordered YBCO sub-micron array structures induced by pulsed femtosecond laser irradiation

We report on the formation of organized sub-micron YBa(2)Cu(3)O(7) (YBCO) dots induced by irradiating femtosecond laser pulses on YBCO films prepared by pulse laser deposition with fluence in the range of 0.21 approximately 0.53 J/cm(2). The morphology of the YBCO film surface depends strongly on the laser fluences irradiated. At lower laser fluence (approximately 0.21 J/cm(2)) the morphology was pattern of periodic ripples with sub-micrometer spacing. Slightly increasing the laser fluence to 0.26 J/cm(2) changes the pattern into organized sub-micron dots with diameters ranging from 100 nm to 800 nm and height of 150 nm. Further increase of the laser fluence to over 0.32 J/cm(2), however, appeared to result in massive melting and led to irregular morphology. The mechanism and the implications of the current findings will be discussed. Arrays of YBCO sub-micron dots with T(c) = 89.7 K were obtained.

Persistent dizziness and nausea in patients receiving postoperative epidural pain control after living donor liver transplantation: case reports

Dizziness and nausea are frequent problems among patients receiving patient-controlled epidural analgesia (PCEA) after major surgery. It is important to consider the various etiologies that might cause these adverse events, especially among patients who have undergone massive hepatic resection for living donor liver transplantation (LDLT). We have described 2 LDLT cases with persistent dizziness and nausea postoperatively despite several adjustments in PCEA management. Their symptoms were quickly relieved after suspension of PCEA medication. Our 2 cases of LDLT represented a unique setting for this type of complication.