Associated genetic polymorphisms and clinical manifestations in systemic lupus erythematosus in Asian populations - A systematic literature review

INTRODUCTION

Systemic lupus erythematosus (SLE) is a chronic and life-threatening autoimmune disease. Its prevalence and clinical manifestations are known to be particularly severe in the Asian populations. Although genetics is known to play an important role in SLE susceptibility and clinical manifestations, the specific polymorphisms associated with these phenotypes in Asia are unclear. Therefore, we aim to review the association of SLE genetic polymorphisms with lupus manifestations across Asian populations and their role in the pathogenesis of SLE.

METHODS

A systematic search was conducted on PubMed, EBSCOHost, and Web of Science. We identified 22 casecontrol studies that matched our inclusion and exclusion criteria. Information such as study characteristics, genetic polymorphisms associated with SLE, and organ manifestations was extracted and reported in this review.

RESULTS

In total, 30 polymorphisms in 16 genes were found to be associated with SLE among Asians. All included polymorphisms also reported associations with various SLE clinical features. The association of rs1234315 in TNFSF4 linking to SLE susceptibility (P=4.17x10-17 OR=1.45 95% CI=1.34-1.59) and musculoskeletal manifestation (P=3.35x10-9, OR=1.37, 95%CI= 1.23-1.51) might be the most potential biomarkers to differentiate SLE between Asian and other populations. In fact, these associated genetic variants were found in loci that were implicated in immune systems, signal transduction, gene expression that play important roles in SLE pathogenesis.

DISCUSSIONS AND CONCLUSIONS

This review summarized the potential correlation between 30 genetic polymorphisms associated with SLE and its clinical manifestations among Asians. More efforts in dissecting the functional implications and linkage disequilibrium of associated variants may be required to validate these findings.

Cost Effectiveness of PD-L1-Based Test-and-Treat Strategy with Pembrolizumab as the First-Line Treatment for Metastatic NSCLC in Hong Kong

BACKGROUND

Pembrolizumab, a monoclonal antibody against programmed death ligand 1 (PD-L1), is approved by several regulatory agencies for first-line treatment of metastatic non-small-cell lung cancer (NSCLC) with a PD-L1 tumor proportion score (TPS) ≥ 50% and no epidermal growth factor receptor (EGFR) or anaplastic lymphoma kinase genomic tumor aberrations. This study was conducted from the perspective of the Hospital Authority in Hong Kong and aimed to evaluate the cost effectiveness of a biomarker (PD-L1) test-and-treat strategy (BTS), in which patients with a TPS ≥ 50% received pembrolizumab and other patients received platinum doublet chemotherapy versus all patients receiving platinum doublet chemotherapy.

METHODS

The model used a partitioned survival approach to estimate the incremental cost-effectiveness ratio (ICER) expressed as the cost per quality-adjusted life-year (QALY) gained. The clinical efficacy, utility and safety data were derived from the KN024 trial. Costs and health outcomes were projected over a 10-year time horizon and discounted at 3% per year. Costs for drug acquisition, PD-L1 testing, drug administration and disease management were used. Sensitivity analyses were conducted to evaluate the robustness of results.

RESULTS

The BTS approach led to an increase of 0.29 QALYs at an additional cost of Hong Kong dollars (HK$) 249,077 (US$31,933) compared with platinum doublet chemotherapy, resulting in an ICER of HK$865,189 (US$110,922) per QALY gained. This is lower than the World Health Organization cost-effectiveness threshold of three times the 2016 gross domestic product (GDP) per capita for Hong Kong of HK$1017,819 (US$130,490). Probabilistic sensitivity analyses showed a 59.4% chance that the ICER would be below this threshold.

CONCLUSION

First-line treatment with pembrolizumab in a BTS to identify patients with NSCLC with PD-L1 TPS ≥ 50% can be considered cost effective in Hong Kong compared with platinum doublet chemotherapy based on a three-times GDP per capita threshold. However, local data on clinical efficacy and safety were not available to estimate overall survival (OS) and progression-free survival (PFS) specific to patients with NSCLC in Hong Kong. Further, uncertainty is inherent in the survival projections/extrapolation of PFS and OS beyond the trial period, and future research may help to further inform these parameters.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method development for screening of potential tamoxifen-drug/herb interaction via in vitro cytochrome P450 inhibition assay

Screening for potential drug-drug interaction (DDI) or herb-drug interaction (HDI) using in vitro cytochrome P450 inhibition (IVCI) assays requires robust analytical methods with high sensitivity and reproducibility. Utilization of liquid chromatography-mass spectrometry (LC-MS) for analyte quantification is often hampered by the presence of non-volatile IVCI sample buffer constituents that often results in ion suppression. In this study, to enable screening of drug interactions involving tamoxifen (TAM) metabolism using IVCI-LC-MS/MS, a liquid-liquid extraction (LLE) method was developed and optimized for sample clean-up. Utilization of chloroform as extraction solvent and adjustment of sample pH to 11 was found to result in satisfactory recovery (>70%) and low ion suppression (<19%). A LC-MS/MS method was subsequently developed and validated for simultaneous quantification of major TAM metabolites, such as N-desmethyltamoxifen (NDT), endoxifen (EDF) and 4-hydroxytamoxifen (HTF) to enable IVCI sample analysis. Satisfactory separation of E-/Z-isomers of endoxifen with peak resolution (Rs) of 1.9 was achieved. Accuracy and precision of the method was verified within the linear range of 0-50 ng/mL for NDT, 0-25 ng/mL for HTF and 0-25 ng/mL for EDF (E/Z isomers). Inhibitory potency (IC50, Ki and mode of inhibition) of known CYP inhibitors and Strobilanthes crispus extract was then evaluated using the validated method. In summary, the results demonstrated applicability of the developed LLE and validated LC-MS/MS method for in vitro screening of DDI and HDI involving TAM metabolism.

Cost-effectiveness analysis of pembrolizumab compared to standard of care as first line treatment for patients with advanced melanoma in Hong Kong

Background

Pembrolizumab has been shown to improve overall survival (OS) and progression free survival (PFS) compared to ipilimumab in patients with ipilimumab-naïve advanced melanoma; however, there are no published data on the cost-effectiveness for pembrolizumab compared to standard-of-care treatments currently used in Hong Kong for advanced melanoma.

Methods

A partitioned-survival model based on data from a recent randomized phase 3 study (KEYNOTE-006) and meta-analysis was used to derive time in PFS, OS, and post-progression survival for pembrolizumab and chemotherapy, such as dacarbazine (DTIC), temozolomide (TMZ), and the paclitaxel-carboplatin combination (PC). A combination of clinical trial data, published data, results of meta-analysis, and melanoma registry data was used to extrapolate PFS and OS curves. The base-case time horizon for the model was 30 years with costs and health outcomes discounted at a rate of 5% per year. Individual patient level data on utilities and frequencies of adverse events were obtained from the final analysis of KEYNOTE-006 (cut-off date: 3-Dec-15) for pembrolizumab. Cost data included drug acquisition, treatment administration, adverse event management, and clinical management of advanced melanoma. The distribution of patient weight from the Hong Kong population was applied to calculate the drug costs. Analyses were performed from a payer's perspective. The incremental cost effectiveness ratio (ICER) expressed as cost in US Dollars (USD) per quality-adjusted life years (QALYs) was the main outcome.

Results

In base-case scenario, the ICER for pembrolizumab as a first-line treatment for advanced melanoma was USD49,232 compared to DTIC, with the ICER values lower than cost-effectiveness threshold in Hong Kong. Results comparing pembrolizumab to TMZ and to PC were similar to that when compared to DTIC. Probability sensitivity analyses showed that 99% of the simulated ICERs were below three times the Gross Domestic Product (GDP) per capita for Hong Kong (currently at $119,274//QALY threshold). In a scenario analysis comparing pembrolizumab with ipilimumab, the estimated ICER was USD8,904.

Conclusions

Pembrolizumab is cost-effective relative to chemotherapy (DTIC, TMZ and PC), and highly-cost-effective compared to ipilimumab, for the first-line treatment of advanced melanoma in Hong Kong.

Cost-effectiveness analysis of FOLFOX4 and sorafenib for the treatment of advanced hepatocellular carcinoma in China

Objectives

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths globally. In China, sorafenib and oxaliplatin plus infusional-fluorouracil/leucovorin (FOLFOX4) are approved for the systemic treatment of advanced HCC. This study compared the cost-effectiveness of these therapies from a healthcare system perspective and a patient perspectives.

Methods

A Markov model was constructed using overall and progression-free survival rates and adverse event (AE) rate from two randomized controlled studies of advanced HCC patients from Asia: EACH for FOLFOX4 and ORIENTAL for sorafenib. The patients in the Markov model were followed until death, the length of each Markov cycle was 1 month, and the survival was adjusted for quality-adjusted life years (QALYs). Direct medical costs included costs of therapies, AE treatment, general ward and tests. Costs were derived from published sources, interviews with oncologists and hospital data from China. One-way and probabilistic sensitivity analyses (PSA) were performed to test the robustness of the results.

Results

From the healthcare system perspective, FOLFOX4 dominated sorafenib with lower therapy costs (FOLFOX4: US$ 6972; sorafenib: US$ 12,289), lower direct medical costs (FOLFOX4: US$ 8428; sorafenib: US$ 12,798), and higher QALYs (FOLFOX4: 0.42; sorafenib: 0.38) per patient. This result was robust according to comprehensive one-way sensitivity analyses. According to the PSA, at the cost-effectiveness threshold for China (3 × GDP, US$ 22,073), FOLFOX4 should be chosen in 63.9% of simulations. From the patient perspective, FOLFOX4 also dominated sorafenib.

Conclusions

The study results indicate that FOLFOX4 dominates sorafenib because it appears to provide higher effectiveness with significantly lower costs in treating Chinese advanced HCC patients.

Impact of ledipasvir/sofosbuvir on the work productivity of genotype 1 chronic hepatitis C patients in Asia

Chronic, untreated hepatitis C virus (HCV) infection is associated with a poor clinical prognosis and a detrimental impact on patients' lives, including on work productivity. To estimate the value of productivity losses due to genotype 1 (GT1) HCV infection in Hong Kong, Singapore, South Korea and Taiwan and to estimate the potential productivity gains associated with treating patients with ledipasvir/sofosbuvir (LDV/SOF) therapy, an economic model was developed with a time horizon of 1 year. Hepatitis C virus patients entered the model at 12 weeks post-treatment, having achieved or not achieved sustained virological response (SVR). Absenteeism and presenteeism rates were taken from a pooled analysis of data from the ION 1-3 studies. These rates were converted into hours of lost productivity, multiplied by the average wage and applied to the total employed, adult GT1 population in each country. Results were compared assuming no treatment, and assuming all patients were treated with LDV/SOF. Total productivity losses due to untreated HCV were: $11.3 million, $17.1 m, $146.0 m and $349.1 m in Hong Kong, Singapore, South Korea and Taiwan. LDV/SOF treatment resulted in economic gains of $4.5 m, $6.8 m, $58.7 m and $138 m, respectively. These gains were due to reduced presenteeism. The results were sensitive to changes in the prevalence of HCV and the average wage. In conclusion, productivity losses due to untreated HCV infection represent a substantial economic burden. By instituting universal HCV treatment with LDV/SOF (or other therapies with high SVR rates), productivity gains can be achieved.

An analysis of genetic association in opioid dependence susceptibility

WHAT IS KNOWN

Drug addiction is a novelty-seeking personality trait that is associated with the candidate genes OPRD1 (opioid delta receptors), OPRK1 (opioid kappa receptors) and PDYN (prodynorphin). However, associations between single nucleotide polymorphisms (SNPs) rs1042114 (80G>T) of the OPRD1 gene, rs702764 (843 A>G) of the OPRK1 gene, and rs910080 (3' UTR _743T>C), rs1997794 (5' UTR -381A>G) and rs1022563 (3' UTR) of the PDYN gene and novelty seeking remain controversial as reported results have not been reproducible.

OBJECTIVE

The goal of this study was to determine the frequencies of SNPs rs1042114, rs702764, rs1997794, rs1022563 and rs910080 in the Malaysian population and to study their association with opioid dependence in Malaysian Malays.

METHODS

A total of 459 Malay male with opioid dependence and 543 healthy male (controls) subjects were included in this study. SNPs were genotyped using the TaqMan SNP genotyping assay. Statistical analysis was performed using Golden Helix SVS software suite to identify the distribution of allele and genotype frequencies, and SNP-SNP interactions were also analysed in this study.

RESULTS AND DISCUSSION

SNP rs1042114 in the OPRD1 gene is strongly associated with opiate addiction (P=.0001). In individuals homozygous for this risk allele, the likelihood of opiate addiction is increased by a factor 1.62 (95% confidence interval (CI) 1.412-1.875). Polymorphic alleles at SNP rs702764 of OPRK1 were not associated with opioid dependence. A significant association between opioid dependence and SNP rs910080 of PDYN (P=.0217) was detected, but there was no association for SNPs rs199774 and rs1022563. A significant interaction was also identified between homozygous wild-type genotype TT of rs702764 with the risk genotypes TG/GG of rs1042114 (odds ratio (OR)=2.111 (95% CI 1.227-3.631), P=.0069) and with the risk genotypes GA/AA of rs910080 (OR=1.415 (95% CI 1.04-1.912), P=.0239).

WHAT IS NEW AND CONCLUSION

The results indicate that SNPs rs1042114 and rs910080 contribute to vulnerability to opioid dependence in the Malaysian Malay population. These results will help us to understand the effect of the SNPs and the SNP-SNP interaction on opioid dependence and may assist in efforts to screen vulnerable individuals and match them with individually tailored prevention and treatment strategies.

Societal implications of medical insurance coverage for imatinib as first-line treatment of chronic myeloid leukemia in China: a cost-effectiveness analysis

OBJECTIVES

Imatinib (Glivec) and nilotinib (Tasigna) have been covered by critical disease insurance in Jiangsu province of China since 2013, which changed local treatment patterns and outcomes of patients with chronic myeloid leukemia (CML). This study evaluated the long-term cost-effectiveness of insurance coverage with imatinib as the first-line treatment for patients with CML in China from a societal perspective.

METHODS

A decision-analytic model based on previously published and real-world evidence was applied to simulate and evaluate the lifetime clinical and economic outcomes associated with CML treatments before and after imatinib was covered by medical insurance. Incremental cost-effectiveness ratio (ICER) was calculated with both costs and quality-adjusted life years (QALYs) discounted at 3% annually. Different assumptions of treatment benefits and costs were taken to address uncertainties and were tested with sensitivity analyses.

RESULTS

In base case analysis, both cost and effectiveness of CML treatments increased after imatinib was covered by the medical insurance; on average, the incremental QALY and cost were 5.5 and ¥277,030 per patient in lifetime, respectively. The ICER of insurance coverage with imatinib was ¥50,641, which is less than the GDP per capita of China. Monte Carlo simulation resulted in the estimate of 100% probability that the insurance coverage of imatinib is cost-effective. Total cost was substantially saved at 5 years after patients initiated imatinib treatment with insurance coverage compared to no insurance coverage, the saved cost at 5 years was ¥99,565, which included the cost savings from both direct (e.g. cost of bone marrow or stem cell transplant) and indirect costs (e.g. productivity loss of patients and care-givers).

CONCLUSIONS

The insurance coverage of imatinib is very cost-effective in China, according to the local cost and clinical data in Jiangsu province. More importantly, the insurance coverage of imatinib and nilotinib have changed the treatment patterns of CML patients, thus dramatically increasing life expectancy and quality-of-life (QoL) saving on productivity losses for both CML patients and their caregivers.

The impact of medical insurance coverage and molecular monitoring frequency on outcomes in chronic myeloid leukemia: real-world evidence in China

OBJECTIVES

Imatinib (Glivec) has been covered by critical disease insurance for treatment of chronic myeloid leukemia (CML) in Jiangsu province of China since 2013. Further, free molecular monitoring has been provided to patients at top clinical centers as part of a pilot study that has changed the local treatment pattern and outcomes of patients with CML. This study evaluates the impact of medical insurance coverage and the molecular monitoring frequency on outcomes of patients with CML treated at a central hospital in Jiangsu, China, according to patient-level data.

METHODS

The study investigated 335 CML patients receiving medical treatment in a central hospital between January 1, 2011 and December 31, 2014. Demographic and clinical characteristics were extracted from the patients' clinical records. Univariate and multivariate analyses using the logistic regression model were performed to identify the differences in outcomes of major molecular response (MMR) or complete cytogenetic response (CCyR) between patients who were insured vs uninsured, or between patients with frequency of PCR monitoring ≤2 times vs ≥3 times per year.

RESULTS

Both the achievement of MMR (BCR-ABL^IS ≤0.1%) (50.4% vs 37.5%) and CCyR (80.7% vs 62.8%) at 12 months have shown significant differences that favored patients with insurance coverage of imatinib, while there was no significant difference in the outcome of BCR-ABL^IS ≤1% between insured and non-insured groups (56.0% vs 51.3%) at 6 months. The long-term results at 24 months demonstrated that there was a statistically significant difference in MMR rates between the group with 3 or more PCR monitoring tests per year and the group of patients with 2 or less PCR tests per year (76.9% vs 52.2%).

CONCLUSIONS

The study findings suggest that CML patients benefit from insurance coverage of imatinib and higher frequency (≥3) of regularly scheduled molecular monitoring PCR in China.

Economic Evaluation of Sevelamer versus Calcium-based Binders in Treating Hyperphosphatemia among Patients with End-stage Renal Disease in China

PURPOSE

To conduct a cost-effectiveness analysis study of sevelamer versus calcium-based binders (CBBs) in treating hyperphosphatemia among patients with end-stage renal disease (ESRD) in China.

METHODS

A decision-analytic model of a lifetime horizon was used for base case analysis from the payers' perspective. The transition probabilities between different health states were derived from survival analysis. The overall survival of CBBs was derived from the Dialysis Clinical Outcomes Revisited study for up to 44 months and a Weibull regression model was used to extrapolate the overall survival to a lifetime horizon. A hazard ratio (0.54; 95% CI, 0.32-0.93) of the overall survival for sevelamer versus CBBs was used to calculate the survival of the sevelamer group. Clinical and cost data were derived from literature and health care system in the local setting. Incremental life year and quality-adjusted life year (QALY) were the primary outcomes. One-way and probabilistic sensitivity analyses were conducted to assess the uncertainty of the model assumptions and parameters. The results were reported in 2015 Chinese Renminbi.

FINDINGS

The incremental cost per life year and per QALY gained of sevelamer versus CBBs was ¥44,475 and ¥57,910, respectively. The incremental cost per QALY gained was below the World Health Organization's recommended cost-effectiveness threshold (¥151,070), which is 3 times the gross domestic product per capita of 2015 in China. The incremental cost-effectiveness ratio was most sensitive to the hazard ratio of overall survival with sevelamer versus CBBs in the 1-way sensitivity analysis. The cost-effectiveness acceptability curve indicated that sevelamer had a 89.6% likelihood of cost-effectiveness at the ¥151,070 threshold.

IMPLICATIONS

Sevelamer is likely to be a cost-effective option in treating hyperphosphatemia among patients with ESRD compared with CBBs in the local context of China.

A Cost-Effectiveness Analysis of Clopidogrel for Patients with Non-ST-Segment Elevation Acute Coronary Syndrome in China

INTRODUCTION

There are a number of economic evaluation studies of clopidogrel for patients with non-ST-segment elevation acute coronary syndrome (NSTEACS) published from the perspective of multiple countries in recent years. However, relevant research is quite limited in China. We aimed to estimate the long-term cost effectiveness for up to 1-year treatment with clopidogrel plus acetylsalicylic acid (ASA) versus ASA alone for NSTEACS from the public payer perspective in China.

METHODS

This analysis used a Markov model to simulate a cohort of patients for quality-adjusted life years (QALYs) gained and incremental cost for lifetime horizon. Based on the primary event rates, adherence rate, and mortality derived from the CURE trial, hazard functions obtained from published literature were used to extrapolate the overall survival to lifetime horizon. Resource utilization, hospitalization, medication costs, and utility values were estimated from official reports, published literature, and analysis of the patient-level insurance data in China. To assess the impact of parameters' uncertainty on cost-effectiveness results, one-way sensitivity analyses were undertaken for key parameters, and probabilistic sensitivity analysis (PSA) was conducted using the Monte Carlo simulation.

RESULTS

The therapy of clopidogrel plus ASA is a cost-effective option in comparison with ASA alone for the treatment of NSTEACS in China, leading to 0.0548 life years (LYs) and 0.0518 QALYs gained per patient. From the public payer perspective in China, clopidogrel plus ASA is associated with an incremental cost of 43,340 China Yuan (CNY) per QALY gained and 41,030 CNY per LY gained (discounting at 3.5% per year). PSA results demonstrated that 88% of simulations were lower than the cost-effectiveness threshold of 150,721 CYN per QALY gained. Based on the one-way sensitivity analysis, results are most sensitive to price of clopidogrel, but remain well below this threshold.

CONCLUSION

This analysis suggests that treatment with clopidogrel plus ASA for up to 1 year for patients with NSTEACS is cost effective in the local context of China from a public payers' perspective.

FUNDING

Sanofi China.

Review of cardiovascular disease prevention and control programs: international experience and challenges in China

<p style="margin: 0cm 9.35pt 0pt 0cm; text-align: justify; -ms-text-justify: inter-ideograph;"><span style="line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt;" lang="EN-GB">Major cardiovascular risk factors in China</span><span style="line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt; mso-fareast-font-family: 宋体; mso-fareast-theme-font: minor-fareast; mso-fareast-language: ZH-CN;" lang="EN-GB">, such as hyperlipidemia, hypertension, dietary factors, exposure to tobacco, diabetes, obesity and physical inactivity, </span><span style="line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt;" lang="EN-GB">have contributed to deteriorating trends in cardiovascular disease (CVD) deaths. In past years, a number of CVD prevention programs have been initiated in European and American countries and successfully brought down CVD related death rate by involving various parties such as physicians, patients, government agencies and payers. However, there is </span><span style="line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt; mso-fareast-font-family: 宋体; mso-fareast-theme-font: minor-fareast; mso-fareast-language: ZH-CN;" lang="EN-GB">rare</span><span style="line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt;" lang="EN-GB"> published literature that systemically reviewed such experience, which would be highly valuable for China and other countries with high CVD burden. In this article, we review the published literature on CVD prevention and control programs and report on interviews of local and foreign experts to provide recommendations for China-specific CVD prevention </span><span style="line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt; mso-fareast-font-family: 宋体; mso-fareast-theme-font: minor-fareast; mso-fareast-language: ZH-CN;" lang="EN-GB">and control </span><span style="line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt;" lang="EN-GB">programs. </span><span style="line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt; mso-fareast-font-family: 宋体; mso-fareast-theme-font: minor-fareast; mso-fareast-language: ZH-CN;" lang="EN-GB">In order to provide practical suggestions, w</span><span style="line-height: 200%; font-family: 'Times New Roman','serif'; font-size: 12pt;" lang="EN-GB">e describe the type of programs as patient, physician, pharmacist, nurse, or payer-focused. Based on this evidence and identified challenges in China, programs focusing on disease management, treatment adherence, physician/health care provider education, financial incentives, and integrated healthcare are recommended for the prevention and control of CVD in China.</span></p>

Epidemiology of dyslipidemia in Chinese adults: meta-analysis of prevalence, awareness, treatment, and control

BACKGROUND

Numerous epidemiology studies on dyslipidemia have been conducted in China. However, a nationally representative estimate for dyslipidemia prevalence is lacking. The aim of this study is to appraise the nationwide prevalence, awareness, treatment, and control rates of dyslipidemia in adults in China.

METHODS

We performed a systematic review of the related observational studies published since 2003 by searching English and Chinese literature databases. Meta-analyses were conducted in eligible studies using a random effect model to summarize the dyslipidemia prevalence, awareness, treatment, and control rates. Heterogeneity and publication bias were analyzed. Sensitivity analyses were performed to explain heterogeneity and examine the impact of study quality on the results of meta-analyses.

RESULTS

Thirty-eight papers were included for meta-analyses, with a total sample size of 387,825. The prevalence, awareness, treatment, and control rates of dyslipidemia were 41.9% (95% CI: 37.7% - 46.2%), 24.4% (95% CI: 14.4% - 38.4%), 8.8% (95% CI: 7.7% - 10.0%), and 4.3% (95% CI: 4.1% - 4.5%), respectively. The prevalence of hypercholesterolemia, hypertriglyceridemia, mixed hyperlipidemia, low levels of high-density lipoprotein cholesterol, and high levels of low-density lipoprotein cholesterol were 10.1% (95% CI: 5.8% - 16.9%), 17.7% (95% CI: 14.0% - 22.1%), 5.1% (95% CI: 3.1% - 8.2%), 11.0% (95% CI: 8.0% - 15.0%), and 8.8% (95% CI: 4.1% - 17.8%), respectively. Sensitivity analyses revealed that males had a higher prevalence of dyslipidemia (43.2%) than females (35.6%). Study samples of age 30 and above in the eastern region tended to have higher prevalence of dyslipidemia. The quality of the studies has a slight impact on the pooled estimates.

CONCLUSIONS

The overall pooled prevalence of dyslipidemia in Chinese adults was estimated to be 41.9%, with males having a higher rate than females.

Prenylated xanthones from mangosteen as promising cholinesterase inhibitors and their molecular docking studies

Garcinia mangostana is a well-known tropical plant found mostly in South East Asia. The present study investigated acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities of G. mangostana extract and its chemical constituents using Ellman's colorimetric method. Cholinesterase inhibitory-guided approach led to identification of six bioactive prenylated xanthones showing moderate to potent cholinesterases inhibition with IC50 values of lower than 20.5 μM. The most potent inhibitor of AChE was garcinone C while γ-mangostin was the most potent inhibitor of BChE with IC50 values of 1.24 and 1.78 μM, respectively. Among the xanthones, mangostanol, 3-isomangostin, garcinone C and α-mangostin are AChE selective inhibitors, 8-deoxygartanin is a BChE selective inhibitor while γ-mangostin is a dual inhibitor. Preliminary structure-activity relationship suggests the importance of the C-8 prenyl and C-7 hydroxy groups for good AChE and BChE inhibitory activities. The enzyme kinetic studies indicate that both α-mangostin and garcinone C are mixed-mode inhibitors, while γ-mangostin is a non-competitive inhibitor of AChE. In contrast, both γ-mangostin and garcinone C are uncompetitive inhibitors, while α-mangostin is a mixed-mode inhibitor of BChE. Molecular docking studies revealed that α-mangostin, γ-mangostin and garcinone C interacts differently with the five important regions of AChE and BChE. The nature of protein-ligand interactions is mainly hydrophobic and hydrogen bonding. These bioactive prenylated xanthones are worthy for further investigations.

Indirect comparison of randomised controlled trials: comparative efficacy of dexlansoprazole vs. esomeprazole in the treatment of gastro-oesophageal reflux disease

BACKGROUND

Dexlansoprazole is a new proton pump inhibitor (PPI) with a dual delayed-release system. Both dexlansoprazole and esomeprazole are an enantiomer of lansoprazole and omeprazole respectively. However, there is no head-to-head trial data or indirect comparison analyses between dexlansoprazole and esomeprazole.

AIM

To compare the efficacy of dexlansoprazole with esomeprazole in healing erosive oesophagitis (EO), the maintenance of healed EO and the treatment of non-erosive reflux disease (NERD).

METHODS

Randomised Controlled Trials (RCTs) comparing dexlansoprazole or esomeprazole with either placebo or another PPI were systematically reviewed. Random-effect meta-analyses and adjusted indirect comparisons were conducted to compare the treatment effect of dexlansoprazole and esomeprazole using a common comparator. The relative risk (RR) and 95% confidence interval (CI) were calculated.

RESULTS

The indirect comparisons revealed significant differences in symptom control of heartburn in patients with NERD at 4 weeks. Dexlansoprazole 30 mg was more effective than esomeprazole 20 mg or 40 mg (RR: 2.01, 95% CI: 1.15-3.51; RR: 2.17, 95% CI: 1.39-3.38). However, there were no statistically significant differences between the two drugs in EO healing and maintenance of healed EO. Comparison of symptom control in healed EO was not able to be made due to different definitions used in the RCTs.

CONCLUSIONS

Adjusted indirect comparisons based on currently available RCT data suggested significantly better treatment effect in symptom control of heartburn in patients with NERD for dexlansoprazole against esomeprazole. No statistically significant differences were found in other EO outcomes. However, these study findings need to be interpreted with caution due to small number of studies and other limitations.

Hydrothermally-grown ZnO nanowire tips for scanning tunnelling microscopy

The probe tip is pivotal in determining the resolution and nature of features observed in the Scanning Tunnelling Microscope (STM). We have augmented a conventional Pt/Ir metallic tip with a hydrothermally grown ZnO nanowire (NW). Atomic resolution imaging of graphite is attained. Current-voltage (IV) characteristics demonstrate an asymmetry stemming from the unintentional n-type doping of the ZnO NW, whereas the expected Schottky barrier at the ZnO-Pt/Ir interface is shown to have negligible effect. Moreover the photoconductivity of the system is investigated, paving the way towards a photodetector capable of atomic resolution.

MR imaging of tophaceous gout revisited

Gout is the most common form of microcrystalline arthropathy, and does not usually pose a diagnostic challenge when patients have a typical presentation, appropriate biochemical picture and classical radiographic appearance. However, magnetic resonance (MR) imaging is increasingly used as the first-line imaging modality in patients with first presentation of joint pain or mass, and tophaceous gout is frequently a forgotten differential diagnosis. This article serves to review the MR imaging characteristics and appearance of gouty tophi in various joints, their clinical presentations and complications, as well as the common differential diagnoses.

Gemcitabine for the treatment of metastatic breast cancer

This paper presents a summary of the evidence review group (ERG) report into the evidence for the clinical effectiveness and cost-effectiveness of gemcitabine with paclitaxel for the first-line treatment of metastatic breast cancer (MBC) in patients who have already received chemotherapy treatment with an anthracycline, compared with current standard of care, based upon the manufacturer's submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The clinical evidence for gemcitabine as a treatment for MBC comes from the unpublished JHQG trial (some data commercial-in-confidence): overall survival was 3 months longer for the gemcitabine/paclitaxel arm (18.5 months) than for the paclitaxel arm (15.8 months) (p = 0.0489); gemcitabine/paclitaxel also improved tumour response and time to documented progression of disease compared with paclitaxel monotherapy, but haematological serious adverse events were more common. In the absence of any formal methods of indirect comparison there is insufficient robust evidence to compare the relative effectiveness of gemcitabine/paclitaxel with docetaxel monotherapy or docetaxel/capecitabine combination therapy. The manufacturers used a Markov state transition model to estimate the effect of treatment with five different chemotherapy regimes, adopting a 3-year time horizon with docetaxel monotherapy as the comparator. Health state utilities for different stages of disease progression and for patients experiencing treatment-related toxicity are used to derive quality-adjusted life expectancy with each treatment. The base-case cost-effectiveness estimate for gemcitabine/paclitaxel versus docetaxel is 17,168 pounds per quality-adjusted life-year (QALY). When longer survival with docetaxel is assumed in a sensitivity analysis, the incremental cost-effectiveness ratio (ICER) is 30,000 pounds per QALY. Probabilistic sensitivity analysis estimates a 70% probability of gemcitabine/paclitaxel being cost-effective relative to docetaxel at a willingness-to-pay threshold of 35,000 pounds. There is considerable uncertainty over the results because of the lack of formal quality assessment or assessment of the comparability of the 15 trials included in the input data, and the questionable validity of the indirect comparison method adopted. An illustrative analysis using a different method for indirect comparison carried out by the ERG produces an ICER of 45,811 pounds per QALY for gemcitabine/paclitaxel versus docetaxel. The guidance issued by NICE in November 2006 as a result of the STA states that gemcitabine in combination with paclitaxel, within its licensed indication, is recommended as an option for the treatment of MBC only when docetaxel monotherapy or docetaxel plus capecitabine is also considered appropriate.

Gemcitabine for the treatment of metastatic breast cancer

This paper presents a summary of the evidence review group (ERG) report into the evidence for the clinical effectiveness and cost-effectiveness of gemcitabine with paclitaxel for the first-line treatment of metastatic breast cancer (MBC) in patients who have already received chemotherapy treatment with an anthracycline, compared with current standard of care, based upon the manufacturer’s submission to the National Institute for Health and Clinical Excellence (NICE) as part of the single technology appraisal (STA) process. The clinical evidence for gemcitabine as a treatment for MBC comes from the unpublished JHQG trial (some data commercial-in-confidence): overall survival was 3 months longer for the gemcitabine/paclitaxel arm (18.5 months) than for the paclitaxel arm (15.8 months) (p = 0.0489); gemcitabine/paclitaxel also improved tumour response and time to documented progression of disease compared with paclitaxel monotherapy, but haematological serious adverse events were more common. In the absence of any formal methods of indirect comparison there is insufficient robust evidence to compare the relative effectiveness of gemcitabine/paclitaxel with docetaxel monotherapy or docetaxel/capecitabine combination therapy. The manufacturers used a Markov state transition model to estimate the effect of treatment with five different chemotherapy regimes, adopting a 3-year time horizon with docetaxel monotherapy as the comparator. Health state utilities for different stages of disease progression and for patients experiencing treatment-related toxicity are used to derive quality-adjusted life expectancy with each treatment. The base-case cost-effectiveness estimate for gemcitabine/paclitaxel versus docetaxel is £17,168 per quality-adjusted life-year (QALY). When longer survival with docetaxel is assumed in a sensitivity analysis, the incremental cost-effectiveness ratio (ICER) is £30,000 per QALY. Probabilistic sensitivity analysis estimates a 70% probability of gemcitabine/paclitaxel being cost-effective relative to docetaxel at a willingness-to-pay threshold of £35,000. There is considerable uncertainty over the results because of the lack of formal quality assessment or assessment of the comparability of the 15 trials included in the input data, and the questionable validity of the indirect comparison method adopted. An illustrative analysis using a different method for indirect comparison carried out by the ERG produces an ICER of £45,811 per QALY for gemcitabine/paclitaxel versus docetaxel. The guidance issued by NICE in November 2006 as a result of the STA states that gemcitabine in combination with paclitaxel, within its licensed indication, is recommended as an option for the treatment of MBC only when docetaxel monotherapy or docetaxel plus capecitabine is also considered appropriate.

Development of a simultaneous liquid-liquid extraction and chiral derivatization method for stereospecific GC-MS analysis of amphetamine-type stimulants in human urine using fractional factorial design

A stereospecific gas chromatography-mass spectrometry analysis method for amphetamine-type stimulants in human urine was recently developed. For maximum efficiency, liquid-liquid extraction and chiral derivatization of the analytes using (R)-(-)-alpha-methoxy-alpha-(trifluoromethyl)phenylacetyl chloride were performed simultaneously. The effects of (1) use of saturated sodium chloride in 2.0 M sodium hydroxide, (2) extraction solvent volume, (3) percentage of triethylamine, (4) derivatization reagent volume, (5) sample mixing time, (6) incubation temperature and (7) incubation time on method sensitivity and variability were assessed using a two-level, eight-run Plackett-Burman design followed by a fold-over design. The use of saturated sodium chloride solution and the derivatization reagent volume were significant factors (ANOVA, p<0.01). The saturated sodium chloride solution decreased sensitivity whereas an increased volume of derivatization reagent increased sensitivity. Calibration curves for all analytes were linear between 5 and 500 microg/L, with correlation coefficients of >0.99. Detection limits were <or=2.3 microg/L and quantitation limits <or=7.7 microg/L. Reproducibility was good, with relative standard deviation values at <20%. Recovery exceeded 100% for most analytes. The experimental design enabled easy and rapid identification of significant factors using a minimal number of samples. This method has good potential for studies requiring rapid and sensitive stereospecific quantification of amphetamine-type stimulants.

Ranibizumab and pegaptanib for the treatment of age-related macular degeneration: a systematic review and economic evaluation

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of ranibizumab and pegaptanib for subfoveal choroidal neovascularisation (CNV) associated with wet age-related macular degeneration (AMD).

DATA SOURCES

Electronic databases were searched from inception to September 2006. Experts in the field were consulted and manufacturers' submissions were examined.

REVIEW METHODS

The quality of included studies was assessed using standard methods and the clinical effectiveness data were synthesised through a narrative review with full tabulation of results. A model was developed to estimate the cost-effectiveness of ranibizumab and of pegaptanib (separately), compared with current practice or best supportive care, from the perspective of the NHS and Personal Social Services. Two time horizons were adopted for each model. The first adopted time horizons determined by the available trial data. The second analysis extrapolated effects of treatment beyond the clinical trials, adopting a time horizon of 10 years.

RESULTS

The combined analysis of two randomised controlled trials (RCTs) of pegaptanib [0.3 mg (licensed dose), 1.0 mg and 3.0 mg] versus sham injection in patients with all lesion types was reported by three publications (the VISION study). Three published RCTs of ranibizumab were identified (MARINA, ANCHOR, FOCUS), and an additional unpublished RCT was provided by the manufacturer (PIER). Significantly more patients lost less than 15 letters of visual acuity at 12 months when taking pegaptanib (0.3 mg: 70% of patients; 1.0 mg: 71% of patients; 3.0 mg: 65% of patients) or ranibizumab (0.3 mg: 94.3-94.5%; 0.5 mg: 94.6-96.4%) than sham injection patients (55% versus pegaptanib and 62.2% versus ranibizumab) or, in the case of ranibizumab, photodynamic therapy (PDT) (64.3%). The proportion of patients gaining 15 letters or more (a clinically important outcome having a significant impact on quality of life) was statistically significantly greater in the pegaptanib group for doses of 0.3 and 1.0 mg but not for 3.0 mg, and for all ranibizumab groups compared to the sham injection groups or PDT. This was also statistically significant for patients receiving 0.5 mg ranibizumab plus PDT compared with PDT plus sham injection. Pegaptanib patients lost statistically significantly fewer letters after 12 months of treatment than the sham group [mean letters lost: 7.5 (0.3 mg), 6.5 (1.0 mg) or 10 (3.0 mg) vs 14.5 (sham)]. In the MARINA and ANCHOR trials, ranibizumab patients gained letters of visual acuity at 12 months whereas patients with sham injection or PDT lost about 10 letters (p<0.001) and in the PIER study, ranibizumab patients lost significantly fewer than the sham injection group. Significantly fewer patients receiving pegaptanib or ranibizumab deteriorated to legal blindness compared with the control groups. Adverse events were common for both pegaptanib andranibizumab but most were mild to moderate. Drug costs for 1 year of treatment were estimated as 4626 pounds for pegaptanib and 9134 pounds for ranibizumab. Non-drug costs accounted for an additional 2614 pounds for pegaptanib and 3120 pounds for ranibizumab. Further costs are associated with the management of injection-related adverse events, from 1200 pounds to 2100 pounds. For pegaptanib compared with usual care, the incremental cost-effectiveness ratio (ICER) ranged from 163,603 pounds for the 2-year model to 30,986 pounds for the 10-year model. Similarly, the ICERs for ranibizumab for patients with minimally classic and occult no classic lesions, compared with usual care, ranged from 152,464 pounds for the 2-year model to 25,098 pounds for the 10-year model.

CONCLUSIONS

Patients with AMD of any lesion type benefit from treatment with pegaptanib or ranibizumab on measures of visual acuity when compared with sham injection and/or PDT. Patients who continued treatment with either drug appeared to maintain benefits after 2 years of follow-up. When comparing pegaptanib and ranibizumab, the evidence was less clear due to the lack of direct comparison through head-to-head trials and the lack of opportunity for indirect statistical comparison due to heterogeneity. The cost-effectiveness analysis showed that the two drugs offered additional benefit over the comparators of usual care and PDT but at increased cost. Future research should encompass trials to compare pegaptanib with ranibizumab and bevacizumab, and to investigate the role of verteporfin PDT in combination with these drugs. Studies are also needed to assess adverse events outside the proposed RCTs, to consider the optimal dosing regimes of these drugs and the benefits of re-treatment after initial treatment, and to review costing in more detail. Health state utilities and their relationship with visual acuity and contrast sensitivity, the relationship between duration of vision loss and the quality of life and functional impact of vision loss, behavioural studies of those genetically at risk are other topics requiring further research.

CYP2A6 polymorphisms in Malays, Chinese and Indians

The genetically polymorphic cytochrome P450 (CYP) 2A6 is the major nicotine-oxidase in humans that may contribute to nicotine dependence and cancer susceptibility. The authors investigated the types and frequencies of CYP2A6 alleles in the three major ethnic groups in Malaysia and CYP2A6*1A, CYP2A6*1B, CYP2A6*1x2, CYP2A6*2, CYP2A6*3, CYP2A6*4, CYP2A6*5, CYP2A6*7, CYP2A6*8 and CYP2A6*10 were determined by allele-specific polymerase chain reaction (PCR) in 270 Malays, 172 Chinese and 174 Indians. Except for CYP2A6*2 and *3 that were not detected in the Malays and Chinese, all the other alleles were detected. Frequencies for the CYP2A6*4 allele were 7, 5 and 2%, respectively, in Malays, Chinese and Indians. A statistically significant high frequency of the duplicated CYP2A6*1x2 allele occurred among Chinese. Among Malays and Chinese, the most common allele was CYP2A6*1B, but it was CYP2A6*1A among Indians. These ethnic difference in frequencies suggested that further studies are required to investigate the implications on diseases such as cancer and smoking behaviour among these major ethnic groups in Malaysia.

The clinical effectiveness and cost-effectiveness of gemcitabine for metastatic breast cancer: a systematic review and economic evaluation

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of gemcitabine, used in combination with paclitaxel, as a second-line treatment for people with metastatic breast cancer who have relapsed following treatment with anthracycline-based chemotherapy.

DATA SOURCES

Electronic databases were searched from inception to March 2006. Clinical advisers were also consulted.

REVIEW METHODS

A systematic review of the literature was undertaken to appraise the clinical and cost-effectiveness of gemcitabine. A Markov state transition model was developed for the economic evaluation.

RESULTS

The systematic review identified only one randomised controlled trials (RCT), and this has not yet been fully published. The methodological quality and quality of reporting of the included trial were assessed to be poor using standard criteria, but this may be due to the lack of information in the limited publications rather than being a fair reflection of the trial's quality. This RCT compared gemcitabine and paclitaxel therapy with paclitaxel monotherapy in 529 patients with metastatic breast cancer who had previously received anthracyclines, but no prior chemotherapy for metastatic breast cancer. Approximately 71% of the gemcitabine/paclitaxel patients survived for 1 year, compared with 61% of the paclitaxel group. The hazard ratio showed a 26% lower chance of survival in the paclitaxel group, and time to progressive disease was also shorter in this group. The overall response rate was higher in the gemcitabine/paclitaxel group than in the paclitaxel group. Adverse events, particularly neutropenia, were more common with gemcitabine/paclitaxel combination therapy than with paclitaxel therapy alone. The economic model was run for a simulation of 1000 patients, assuming that chemotherapy continued until patients' disease progressed. This base-case analysis found an incremental cost-effectiveness ratio (ICER) of 58,876 pounds per quality-adjusted life-year (QALY) gained and 30,117 pounds per life-year gained. The model was re-run with treatment restricted to a maximum of six cycles per patient, reflecting normal practice. This yielded an ICER of 38,699 pounds per QALY gained and 20,021 pounds per life-year gained.

CONCLUSIONS

The review of clinical effectiveness is based on data from a single RCT that has not yet been fully published. While only tentative conclusions can be drawn from this, the evidence may indicate that treatment with gemcitabine and paclitaxel confers an improved outcome for patients in terms of survival and disease progression, but at the cost of increased toxicity. An economic model developed for this review reflects high costs per QALY for this treatment combination. The base-case analysis shows high ICERs, with costs per QALY gained close to 60,000 pounds. Adopting a more realistic treatment protocol, with chemotherapy limited to a maximum of six cycles, gives a more favourable cost-effectiveness estimate. However, this was still higher than would usually be considered to be a cost-effective treatment from the NHS's perspective. Future research recommendations include an update of this review in 12-18 months' time, by which time the included RCT should be fully published. It would also be useful to compare gemcitabine with currently used treatments for metastatic breast cancer, including capecitabine and vinorelbine.

Ranibizumab (Lucentis) versus bevacizumab (Avastin): modelling cost effectiveness

Two new drugs provide startling benefits in the treatment of age-related macular degeneration (AMD). The clinical and cost effectiveness of ranibizumab (Lucentis) was compared to that of bevacizumab (Avastin), which costs up to 100 times less. A cost effectiveness model was developed to assess the cost per quality adjusted life year (QALY) over 10 years. For predominantly classic AMD, the efficacy of bevacizumab relative to ranibizumab would have to be around 40% for the latter to achieve 30 k pounds per QALY, a NICE threshold. Similar but worse results applied to the other main forms of AMD, minimally occult and occult with no classic lesions. The price of ranibizumab would have to be drastically reduced for it to be cost effective. Continued unlicensed use of bevacizumab raises ethical, legal and policy questions. Public pressure may be the most potent weapon in persuading Genentech to license bevacizumab for AMD.

The "U-ligament" for collateral ligament reconstruction in duplicate thumb

Duplicate thumb is a common congenital difference with complex management. Surgical treatment includes reconstruction of the collateral ligaments to optimise future function and cosmesis. We present the use of the "U-ligament" to further refine collateral ligament reconstruction. We have found it to be a simple and reliable technique.

Selective extraction of salbutamol from human plasma with the use of phenylboronic acid

An investigation was conducted on the usage of a single-step extraction procedure involving the retention of a phenylboronate-salbutamol complex on an end-capped C18 solid-phase sorbent to determine the level of salbutamol in human plasma samples. Propranolol, a beta-blocker, was chosen as the internal standard for this assay. In this solid-phase clean-up method, 50 mM sodium carbonate buffer, pH 9.60, was used for conditioning the column as well as washing the endogenous interference. Under the optimal conditions, the recovery of salbutamol from spiked plasma samples was found to be high and reproducible with mean recoveries (n = 3) of more than 90% after elution by using 50% 1 M trifluoroacetic acid in methanol. This sample clean-up step was effectively analyzed under reversed-phase high-performance liquid chromatography with fluorimetric detection. The method was successfully applied to the routine measurement of salbutamol in human plasma from the bioequivalence study on the different administration route of salbutamol. Quantification of salbutamol was convincingly reported with the correlation of coefficient of 0.9980 for the concentration range from 0 to 1000 ng ml(-1). An adequate precision was achieved with both between- and within-day precisions of less than 10% (n = 6) for 100 and 1000 ng ml(-1) and less than 15% (n = 6) for 10 ng ml(-1).

Stereoselectivity of ibuprofen metabolism and pharmacokinetics following the administration of the racemate to healthy volunteers

1. The stereoselective metabolism and pharmacokinetics of the enantiomers of ibuprofen have been investigated following the oral administration of the racemic drug (400 mg) to 12 healthy volunteers.2. The stereochemical composition of the drug in serum, both total and unbound, and drug and metabolites, both free and conjugated, in urine were determined by a combination of the direct and indirect chromatographic procedures to enantiomeric analysis. 3. The oral clearance of (S)-ibuprofen was significantly greater than that of the R-enantiomer (74.5 +/- 18.1 versus 57.1 +/- 11.7 ml min(-1); p < 0.05) and the clearance of (R)-ibuprofen via inversion was ca two fold that via alternative pathways. 4. Some 74.0 +/- 9.6% of the dose was recovered in urine over 24 h as ibuprofen, 2-hydroxyibuprofen and carboxyibuprofen, both free and conjugated with glucuronic acid. Analysis of the stereochemical composition of the urinary excretion products indicated that 68% of the dose of (R)-ibuprofen had undergone chiral inversion. 5. Metabolism via glucuronidation and both routes of oxidation, showed enantio-selectivity for (S)-ibuprofen, the enantiomeric ratios (S/R) in partial metabolic clearance being 7.1, 4.8 and 3.4 for formation of ibuprofen glucuronide, 2-hydroxyibuprofen and carboxyibuprofen respectively.6. Modest stereoselectivity was observed in the formation of (2'R, 2R)- and (2'S, 2S)-carboxyibuprofen in comparison to the alternative diastereoisomers, the ratios in formation clearance being 1.6 and 1.2 respectively.

Flexural strength of a glass-infiltrated alumina dental ceramic incorporated with silicon carbide whiskers

PURPOSE

The addition of silicon carbide whiskers has been known to reinforce ceramics. This study compared the flexural strength of a glass-infiltrated alumina dental ceramic with various amounts of silicon carbide whiskers incorporated into the alumina matrix.

MATERIALS AND METHODS

Three groups with a total of 30 specimens were included: glass-infiltrated alumina dental ceramic with 0, 0.125, and 0.25 wt% silicon carbide whiskers. The flexural strength was measured using a three-point bending test, and the data were analyzed with one-way analysis of variance. Scanning electron microscopy was used to examine the fracture surfaces of all three materials.

RESULTS

There were no significant differences in the flexural strength among the three groups. Glass-infiltrated alumina dental ceramic failed predominantly by transgranular fracture and to a lesser degree by intergranular fracture.

CONCLUSION

The addition of silicon carbide whiskers did not change the flexural strength of glass-infiltrated alumina dental ceramic.

Predictive factors in the evolution of neural deficit in tuberculosis of the spine

This study was conducted to determine the factors involved in predicting the onset of paraplegia in tuberculosis of the spine. A cross-sectional, case control review of 85 cases of spinal tuberculosis was conducted at the National Tuberculosis Centre in Kuala Lumpur. Sixty-nine of these cases were normal neurologically, whilst 16 cases experienced neural deficit. The data was analysed using backward logistic regression and Fishers exact probability test. The factors studied included symptoms and signs of spinal tuberculosis, common investigations for tuberculosis, and physical factors of the disease. Only the erythrocyte sedimentation rate (ESR) showed a significant difference between the neural deficit and neurologically normal groups. This suggests that the ESR may be a factor in predicting evolution of paraplegia in spinal tuberculosis. In addition, it was noted that a low proportion of patients had positive sputum smear results and bacterial culture growth for mycobacterium tuberculosis suggesting these tests are of limited value for tuberculosis of the spine.

Concurrent production of chitin from shrimp shells and fungi

Crustacean shells constitute the traditional and current commercial source of chitin. Conversely, the control of fungal fermentation processes to produce quality chitin makes fungal mycelia an attractive alternative source. Therefore, the exploitation of both of these sources to produce chitin in a concurrent process should be advantageous and is reported here. Three proteolytic Aspergillus niger (strains 0576, 0307 and 0474) were selected from a screening for protease activity from among 34 zygomycete and deuteromycete strains. When fungi and shrimp shell powder were combined in a single reactor, the release of protease by the fungi facilitated the deproteinization of shrimp-shell powder and the release of hydrolyzed proteins. The hydrolyzed proteins in turn were utilized as a nitrogen source for fungal growth, leading to a lowering of the pH of the fermentation medium, thereby further enhancing the demineralization of the shrimp-shell powder. The shrimp-shell powders and fungal mycelia were separated after fermentation and extracted for chitin with 5% LiCl/DMAc solvent. Chitin isolates from the shells were found to have a protein content of less than 5%, while chitin isolates from the three fungal mycelia strains had protein content in the range of 10-15%. The relative molecular weights as estimated by GPC for all chitin samples were in the 10(5) dalton range. All samples displayed characteristic profiles for chitin in their FTIR and solid-state NMR spectra. All chitin samples evaluated with MTT and Neutral Red assays with three commercial cell lines did not display cytotoxic effects.

Detection of Mycoplasma pneumoniae from cerebrospinal fluid samples of pediatric patients

Central nervous system manifestations are probably the most frequent extrapulmonary complications of infections due to Mycoplasma pneumoniae, occur mostly in children. In this study, we attempted to isolate M. pneumoniae and to detect the organism by polymerase chain reaction (PCR) from cerebrospinal fluid samples (CSF) of pediatric patients. Of the 244 CSF samples, no M. pneumoniae was isolated. Six (2.5%) of the CSF samples were positive by PCR amplification. More effort are necessary to isolate the organism from CSF samples in order to ascertain the role of M. pneumoniae in causing neurological complications.

Isolation and polymerase chain reaction detection of Mycoplasma pneumoniae in Malaysian patients with respiratory tract infections

Isolation and polymerase chain reaction (PCR) were performed for detection of Mycoplasma pneumoniae from respiratory tract specimens obtained from 200 adult and 200 pediatric patients. M. pneumoniae was isolated from bronchoalveolar lavage fluid of 1(0.5%) adult patient and 4(2.0%) tracheal aspirates of pediatric patients. PCR was positive for only one (0.5%) broncoalveolar lavage fluid of an adult patient and fifteen (7.5%) tracheal aspirates of pediatric patients. This study suggested that M. pneumoniae was more frequently detected in pediatric patients and PCR appears to have advantages over isolation, in terms of rapidity and sensitivity.

Clean-up, detection and determination of salbutamol in human urine and serum

Salbutamol ¿2-(tert-butylamino)-1-[4-hydroxy-3- (hydroxymethyl)phenyl]ethanol¿, also known as albuterol, is clinically the most widely used beta 2-adrenoceptor agonist in the treatment of bronchial asthma. During this study, we evaluated liquid-liquid extraction (LLE) and solid-phase extraction (SPE) in order to develop a reliable extraction method followed by analysis using liquid chromatography and gas chromatography. An assay is described which involves SPE as the clean-up method followed by gas chromatography-mass spectrometry to determine salbutamol levels in human serum after oral administration. The SPE method requires the use of a hyper-cross-linked styrene-divinylbenzene bonded phase (ENV+) without involving any sample pre-treatment to obtain 60-65% recoveries for salbutamol and terbutaline as the internal standard. Distilled water and 1% trifluoroacetic acid in methanol were found to be the most suitable washing solvent and eluting solvent, respectively. A detection limit of 2 ng mL-1 was achieved by derivatization with N-methyl-N-trimethylsilyltrifluoroacetamide to form trimethylsilyl (TMS)-salbutamol (m/z 369) and TMS-terbutaline (m/z 356). The relationship between the ratio of the peak area of salbutamol to that of the internal standard and concentration was linear for the range tested (2-200 ng mL-1) and the correlation of coefficient was 0.9999 with a y-intercept not significantly different from zero. The inter-day relative standard deviation (RSD) was < 10% for all three concentrations. The intra-day RSD was 14% for 2 ng mL-1. This assay was then successfully applied to human serum samples obtained from clinical trials after oral administration of salbutamol.

Synthesis, chromatographic resolution and chiroptical properties of carboxyibuprofen stereoisomers: major metabolites of ibuprofen in man

The chromatographic resolution of the four stereoisomers of carboxy-ibuprofen, a major metabolite of ibuprofen in man, was achieved using a Chiralpak AD chiral stationary phase (CSP) (J.T. Baker, Milton, Keynes, UK). The elution order of the stereoisomers was determined to be 2'S,2R;2'R,2R;2'R,2S;2'S,2S by a combination of stereoselective synthesis of diastereoisomeric mixtures and analysis of the two diastereoisomers isolated from human urine following the administration of (S)-ibuprofen. The individual stereoisomers were isolated by semipreparative chiral phase chromatography and characterized by circular dichroism spectroscopy.

Ibuprofen stereochemistry: double-the-trouble?

Racemic ibuprofen is an important NSAID used in the treatment of pain and inflammation in a variety of musculoskeletal and rheumatic disorders. The metabolism of ibuprofen, and that of a number of the related 2-arylpropionic acid NSAIDs, involves chiral inversion of the relatively inactive R-enantiomers to their active S-antipodes, together with other potentially stereoselective conjugative and oxidative pathways. Enantiospecific analytical methodology suitable for the determination of both the drug and its metabolites is essential in order to evaluate the significance of stereoselectivity both in terms of drug action and disposition. Recent investigations have also indicated that the R-enantiomers of these agents may not be totally devoid of useful biological activity, that the formation of acyl-coenzyme A derivatives results in interactions with lipid biochemistry, and has provided new insights into the disposition of these drugs in man. Ibuprofen represents a classical example of a drug where stereochemical considerations are essential for an understanding of its biological properties.

Rotavirus electropherotypes from the Kuala Lumpur Hospital: a re-examination after an interval of seven years

The objective of this study was to ascertain the extent changes have occurred in the epidemiology of human rotavirus electropherotypes from the same location 7 to 8 years after an earlier study. Genomic RNA profiles of rotaviruses from diarrhoeic children admitted to the Kuala Lumpur Hospital from April to December 1996 were determined by polyacrylamide gel electrophoresis and silver staining. A total of 179 group A rotaviruses were detected from 870 children: 175 with legible staining of all RNA segments were classified into 14 distinct electropherotypes (10 and 4 with long and short migration patterns respectively). In addition, the results revealed: high predominance of long pattern electropherotypes (94% of the total electropherotypes); most long electropherotypes with RNA profiles which all 11 RNAs migrated separately (8 of 10 electropherotypes); all short electropherotypes had segments 2 and 3 that co-migrated; presence of a very numerically dominant electropherotype (75% of all electropherotypes); frequent co-circulation of the dominant electropherotype-present throughout the study period--with other electropherotypes present for limited periods; sequential temporal appearances by similar electropherotypes. These observations were similar to that of an earlier study conducted in 1988/89. Nevertheless, the dominant electropherotype in the present study was different and not among the electropherotypes detected in the earlier study.

Detection of false positives by incorporation of a confirmatory blocking test into a commercial enzyme-linked immunosorbent assay specific for adenovirus antigen

A blocking test was incorporated into the commercial IDEIA Adenovirus test (DAKO Diagnostics Ltd., Cambridgeshire, UK) to detect false positive results when faecal specimens were tested for adenovirus antigen. Immune rabbit serum raised against pooled adenovirus particles from human faecal specimens, together with the pre-immune serum, was used. Assessment of positive showed that false positives were produced under two different conditions: when results were based on visual determination instead of a cut-off value determined from photometric reading, and when absorbance values were not immediately read at the end of the test. Under the optimum condition for reading and assessment of test results (immediate reading and photometric determination), 11% of 65 adenovirus-positive samples were checked by the blocking ELISA as false positives. The rest of the specimens showed blocking of positive absorbance values by 70 to 98%. ELISA was found to be more sensitive than immune electron microscopy on samples with lower antigen concentration.

Stereospecific analysis of the major metabolites of ibuprofen in urine by sequential achiral-chiral high-performance liquid chromatography

A sequential achiral-chiral HPLC method has been developed for the stereospecific analysis of the two major urinary metabolites of ibuprofen, namely hydroxyibuprofen and carboxyibuprofen. Achiral analysis was carried out using a Partisil column (250x4.6 mm, 5 microm) and a mobile phase of hexane:ethanol (98.2:1.8, v/v) containing trifluoroacetic acid (TFA; 0.05%, v/v) at a flow-rate of 2.0 ml/min. The HPLC eluate containing the two metabolites was separately collected, evaporated under nitrogen and the residue dissolved in the mobile phase used for chiral chromatography. Chiral-phase analysis was carried out using a Chiralpak AD CSP (250x4.6 mm, 10 microm) with a mobile phase of hexane:ethanol (92:8, v/v) containing TFA (0.05%, v/v) at a flow-rate of 1.0 ml/min. In both assays the analytes were quantified by ultraviolet detection at a wavelength of 220 nm. Modification of the mobile-phase composition allowed the resolution of all six analytes in a single chromatographic run but with an increase in run time and consequent band broadening. The analytical method described allows the direct quantitation of the stereoisomers of both metabolites of ibuprofen in urine following the administration of therapeutic doses of the racemic drug to man.

Metabolism of (-)-(S)-nicotine in the isolated perfused rabbit lung

The metabolism of (-)-(S)-nicotine has been investigated following intratracheal administration to the recirculating perfused rabbit lung model. The metabolic products present in the perfusate were identified by co-chromatography (HPLC and GC) with authentic standards and quantified by HPLC. After the 180 min perfusion period, nicotine was found to be metabolically transformed to cotinine (33.7%), 3-hydroxycotinine (10.4%), cotinine-1-N-oxide (3.4%) and nicotine-1'-N-oxide (14.4%). Norcotinine, nornicotine, 3-pyridyl-4-oxo-N-methylbutyramide and an uncharacterised metabolite were also detected in low amounts. Following the perfusion experiment, part of the lung tissue was homogenised in the presence of [14C]-sodium cyanide. Subsequent analysis of the homogenates indicated the formation of 2'-cyanonicotine, 1'-cyanomethylnornicotine and the diastereoisomeric 5'-cyanonicotines.

Drug chirality and its clinical significance

Approximately 1 in 4 therapeutic agents are marked as racemic mixtures, the individual enantiomers of which frequently differ in both their pharmacodynamic and pharmacokinetic profiles. The use of racemates has become the subject of considerable discussion in recent years, and an area of concern for both the pharmaceutical industry and regulatory authorities. The use of single enantiomers has a number of potential clinical advantages, including an improved therapeutic/pharmacological profile, a reduction in complex drug interactions, and simplified pharmacokinetics. In a number of instances stereochemical considerations have contributed to an understanding of the observed pharmacological effects of a drug administered as a racemate. However, relatively little is known of the influence of patient factors (e.g. disease state, age, gender and genetics) on drug enantiomer disposition and action in man. Examples may also be cited where the use of a single enantiomers, nonracemic mixtures and racemates of currently used agents may offer clinical advantages. The issues associated with drug chirality are complex and depend upon the relative merits of the individual agent. In the future it is likely that a number of existing racemates will be re-marketed as single enantiomer products with potentially improved clinical profiles and possible novel therapeutic indications.

Bacterial contamination of hospital disinfectants

A study to determine contamination of diluted disinfectants at different points in preparation and use in 6 Malaysian hospitals was done using the in-use test. A growth of > or = 250 organisms/ml was taken as an indication of contamination. A total of 342 (7.9%) of the 4316 freshly diluted samples collected from disinfectant bottles in the pharmacy were found to be contaminated. The bacterial isolates obtained were Pseudomonas spp. (42.4%), Moraxella spp. (22.0%), Flavobacterium spp. (11.6%) and Enterobacter spp. (4.2%). Three hundred and sixty seven out of 2278 ward stock were contaminated. The isolates were Pseudomonas spp. (48.6%), Moraxella spp. (17.8%), Acinetobacter spp. (8.9%) and Flavobacterium spp. (7.0%). Of the 9265 disinfectants in-use, 1519 (16.4%) were contaminated. Among the organisms isolated were Pseudomonas spp. (44.3%), Bacillus spp. (13.0%), Enterobacter spp. (9.5%) and Acinetobacter spp. (7.3%). The results indicated a high level of contamination of diluted disinfectants prepared in the pharmacy, stored and used in the wards. This gave a high index of suspicion that recommendations for cleaning of disinfectant containers before refilling, handling of diluted stock solutions and using of disinfectants were not closely adhered to. Standard disinfection procedures outlined in the disinfection and sterilization policy by the Ministry of Health should therefore be followed.

Disinfection: gaps between recommended and actual practice

Basic practices on disinfection was surveyed in 6 hospitals using an observation and interview checklist. Two surveys were done, one pre-(first survey) and one post-intervention (second survey). The disinfection and sterilization policy of the Ministry of Health was not available in 66 (70.2%) and 12 (13%) of the units in the first and second survey respectively. In the second survey, staff in all the units washed disinfectant containers before refilling compared with 41.5% of the units in the first survey. Dilution of disinfectants not recommended was found to be used in the first survey. Storing cleaned and sterile items in disinfectants, using disinfectant as a substitute for sterilization of autoclavable items and not decontaminating spillages were some of the wrong practices observed. Considerable improvements were made in the second survey. Improper usage of disinfectants was also indicated by failure of the in-use test. Rate of failure of disinfectants in-use decreased from 11.6% in the first survey to 5.0% in the second survey. To ensure proper disinfection practices, a comprehensive training program on disinfection is required for nurses and attendants.