Switched step integral backstepping control for nonlinear motion systems with application to a laboratory helicopter

In this paper, the energy efficiency of the widespread application of backstepping control to a class of nonlinear motion systems is investigated. A Switched Step Integral Backstepping Control (SSIBC) scheme is introduced to improve immunity to measurement noise and to increase the energy efficiency of conventional backstepping in practice. The SSIBC is realized by switching between two candidate controllers obtained at different steps of the iterative backstepping design process. A bi-state dependent hysteresis rule is developed to supervise stable switching between the different regimes in the presence of noise. The proposed method is experimentally verified on a MIMO twin rotor laboratory helicopter involving coupled nonlinear dynamics, inaccessible states and uncertainties. Experimental results show that in addition to a reduction in power consumption, the SSIBC reduces saturation of the control signal and visible motor jerking in contrast with conventional backstepping. Additional comparisons with a previously proposed optimized decoupling PID controller also show significant improvement in precision achieved with higher energy efficiency. Experimental results obtained with the introduction of an external disturbance into the system also show the robustness of the proposed SSIBC.

Stress perceived by drivers in public healthcare facilities in Negeri Sembilan during the first year of the COVID-19 pandemic

INTRODUCTION

Healthcare drivers, including ambulance drivers, were less concerned about health and safety during the COVID-19 pandemic, with not only the risk of COVID-19 infection but also a higher risk of prolonged states of alertness, stress, burnout, fatigue and road traffic accident. This study aimed to determine the prevalence of stress and its associated factors among healthcare drivers, especially during the COVID-19 pandemic.

MATERIALS AND METHODS

This study employs a crosssectional study design and utilises self-reported data obtained from locally validated personal stress inventory questionnaires. The data collection period spanned from August 1 to 31, 2020. The study sample consisted of 163 healthcare drivers affiliated with the Negeri Sembilan State Health Department. The Chi-square test and Fisher's exact test were the first used to determine the association between variables prior to conducting multiple logistic regression to predict the relationship between dependent and independent variables.

RESULTS

In COVID-19's first year, 7.4% (n = 12) of healthcare drivers reported perceived stress with ambulance drivers reporting more stress (10.6%; n = 5) than non-ambulance drivers (6.0%; n = 7). Simple statistical analysis identified perceived stress significantly associated with household income, smoking status and performing on-call. Further analysis by multiple logistic regression found that perceived stress was significantly related to smoking (aOR 19.9, 95% CI: 1.86-213.90), and performing on-call (aOR 8.69, 95% CI 1.21-62.28). Nevertheless, no association was found between perceived stress and age, ethnicity, marital status, education, household income, co-morbidities, driving assignment, employment duration, needing a part-time job or motor vehicle accident history.

CONCLUSION

The study found that the perceived stress amongst Malaysian healthcare drivers during the COVID-19 pandemic was relatively low. This could be due to fewer lifethreatening tasks, emergencies, assigned tasks and increase income due to overtime during the COVD-19 pandemic. The OSH team's efforts to provide consistent safety and health training, including stress management, may have contributed to the healthcare driver's ability to effectively manage the stressful circumstances encountered during the pandemic. In order to enhance salary competitiveness, employers should provide financial management education alongside subsidised housing and childcare provisions. Healthcare drivers who smoke should be taught different stress reduction techniques so that they can handle their stress in a healthy way.

Systematic Review of Brain-Eating Amoeba: A Decade Update

INTRODUCTION

Primary amoebic meningoencephalitis (PAM) is a rare but lethal infection of the brain caused by a eukaryote called Naegleria fowleri (N. fowleri). The aim of this review is to consolidate the recently published case reports of N. fowleri infection by describing its epidemiology and clinical features with the goal of ultimately disseminating this information to healthcare personnel.

METHODS

A comprehensive literature search was carried out using PubMed, Web of Science, Scopus, and OVID databases until 31 December 2022 by two independent reviewers. All studies from the year 2013 were extracted, and quality assessments were carried out meticulously prior to their inclusion in the final analysis.

RESULTS

A total of 21 studies were selected for qualitative analyses out of the 461 studies extracted. The cases were distributed globally, and 72.7% of the cases succumbed to mortality. The youngest case was an 11-day-old boy, while the eldest was a 75-year-old. Significant exposure to freshwater either from recreational activities or from a habit of irrigating the nostrils preceded onset. The symptoms at early presentation included fever, headache, and vomiting, while late sequalae showed neurological manifestation. An accurate diagnosis remains a challenge, as the symptoms mimic bacterial meningitis. Confirmatory tests include the direct visualisation of the amoeba or the use of the polymerase chain reaction method.

CONCLUSIONS

N. fowleri infection is rare but leads to PAM. Its occurrence is worldwide with a significant risk of fatality. The suggested probable case definition based on the findings is the acute onset of fever, headache, and vomiting with meningeal symptoms following exposure to freshwater within the previous 14 days. Continuous health promotion and health education activities for the public can help to improve knowledge and awareness prior to engagement in freshwater activities.

Association of Dyslipidemia with Endometriosis: A Case Control Study

Endometriosis is a chronic multi-factorial disease characterized by the presence of functioning uterine glands and stroma in any site outside the uterus. Despite the major public health impact of this condition, little is known about their etiologies. Some studies focused on the similarities between the common biological mechanisms underlying the development of endometriosis and atherosclerotic plaques. So, it is possible to hypothesize that same atherogenic risk factors, such as dyslipidemia may play a role in endometriosis pathogenesis. This case-control study was carried out in the department of Obstetrics and Gynaecology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from September 2018 to August 2019 to investigate the lipid profile in patients with endometriosis and to analyze the association of dyslipidemia with endometriosis. A total of 140 participants ranged between 18 and 35 years of age attending BSMMU were enrolled in the study. The study population was divided into case and control group; the case group consisting of patients with endometriosis and control group comprising of healthy women without endometriosis. Fasting lipid profile of all participants was measured in the department of Biochemistry and Molecular Biology of BSMMU, Bangladesh. Doing student's t-test and Chi square test compared results of both groups. Logistic regression analysis was done to see association of dyslipidemia with endometriosis. Women with endometriosis were found to have significantly higher levels of serum total cholesterol (TC), low density lipoprotein (LDL-C), triglyceride (TG) and significantly lower level of high density lipoprotein (HDL-C) compared to the controls (p<0.05). The mean atherogenic index was significantly higher in case group (p<0.05). This study found an association between dyslipidemia and endometriosis.Women with endometriosis have higher atherogenic index compared to women without endometriosis.

Compliance to Infection Prevention and Control Practices Among Healthcare Workers During COVID-19 Pandemic in Malaysia

Healthcare workers (HCWs) are at risk of contracting coronavirus disease-2019 (COVID-19) in their workplace. Infection prevention guidelines and standard operating procedures were introduced to reduce risk of exposure and prevent transmission. Safe practices during interaction with patients with COVID-19 are crucial for infection prevention and control (IPC). This study aimed to assess HCWs' compliance to IPC and to determine its association with sociodemographic and organizational factors. A cross-sectional study was conducted between March and April 2021 at public healthcare facilities in the east coast of Peninsular Malaysia. HCWs who were involved with COVID-19-related works were invited to participate in the online survey. The questionnaire was adapted from the World Health Organization (WHO) Interim Guidance: WHO Risk Assessment and Management of Exposure of Healthcare Workers in the Context of COVID-19. Respondents were categorized as compliant or non-compliant to IPC. A total of 600 HCWs involved in COVID-19-related works participated in the survey. Most of them (63.7%) were compliant to IPC as they responded to all items as “always, as recommended” during interaction with patients with COVID-19. The multivariate analysis showed that non-compliance was significantly associated with working in the emergency department (AOR = 3.16; 95% CI = 1.07–9.31), working as laboratory personnel (AOR = 15.13; 95% CI = 1.36–168.44), health attendant (AOR = 4.42; 95% CI = 1.74–11.24), and others (AOR = 3.63; 95% CI = 1.1–12.01), as well as work experience of more than 10 years (AOR = 4.71; 95% CI = 1.28–17.27). The odds of non-compliance among respondents without adequate new norms and personal protective equipment training were 2.02 (95% CI = 1.08–3.81) more than those with adequate training. Although most of the respondents complied to IPC protocols, compliance status differed according to department, work category, and years of service. Ensuring adequate training that will hopefully lead to behavioral change is crucial to prevent breach in IPC and thus minimize the risk of exposure to and transmission of COVID-19 in healthcare facilities.

CD68-positive tumour associated macrophages, PD-L1 expression, and EBV latent infection in a high HIV-prevalent South African cohort of Hodgkin lymphoma patients

A higher proportion of CD68-positive tumour associated macrophages (TAMs) has been associated with poorer outcomes in HIV-negative patients with Hodgkin lymphoma (HL), but whether this is true in HIV-positive patients with HL is not known. In this study, we investigated the number of CD68-positive TAMs and expression of programmed cell death-ligand 1 (PD-L1) in lymph node specimens from HL patients and correlated expression with clinical features (HIV status, disease severity and survival) and histopathological features (EBV latent positivity and subtype of HL). We stained archived lymph node specimens from 77 patients diagnosed with HL for CD68 and PD-L1. Stains were graded as: CD68 low (≤25%), CD68 high (>25%), PD-L1 low (≤50%), and PD-L1 high (>50%). Expression levels were correlated with the clinical and histopathological features using bivariate and multivariate analyses. Survival was analysed by overall and progression-free survival. Thirty-four of the 77 included patients (44%) were HIV-positive. EBV latency was detected in 97% of HIV-positive HL patients and in 14% of HIV-negative HL patients. A high CD68 score was associated with lower median haemoglobin levels (9.4 vs 11.4 g/dL; p=0.02), platelet numbers (262 vs 424 cells ×10⁹/L; p=0.01), and lymphocyte numbers (0.99 vs 1.70 cells ×10⁹/L, p=0.01) and a trend towards advanced disease (international prognostic score ≥4; hazard ratio 2.4; confidence interval 0.89-6.47; p=0.08). HIV status did not affect CD68 or PD-L1 expression. A higher proportion of CD68-positive TAMs was found in samples that were EBV-positive. HIV positivity and EBV negativity correlated with poorer survival. CD68 and PD-L1 expression were not predictive of survival. High CD68 expression was associated with EBV positivity but not HIV positivity and did not predict adverse outcomes. PD-L1 expression was unaffected by HIV status or EBV positivity and did predict adverse outcomes.

Improved integral backstepping control of variable speed motion systems with application to a laboratory helicopter

This paper proposes an improved method of integral backstepping for real time control of a laboratory helicopter with variable speed rotors known as the Two-Rotor Aero-dynamic System (TRAS). The coupled system is decomposed into the horizontal subsystem (HS) and the vertical subsystem (VS) and traditional backstepping, augmented with direct integral action is designed for each subsystem. The transient response to both constant and time varying references is then simultaneously improved by modifying an already proposed method called dual boundary conditional integration. A switching technique is also employed to enhance the tracking response of the undamped HS for its bi-directional motor which exhibits jerking effects. Experimental results show that the proposed approach yields improved transient and tracking performance when compared to previously proposed methods exploiting conditional integration earlier proposed for improving the transient response of controlled nonlinear systems with integral action. The results also show the robustness of the proposed method in the presence of the coupling effects and additional external disturbance applied to the system in the form of a wind gust.

Next generation sequencing (NGS) to improve the diagnosis and management of patients with disorders of sex development (DSD)

Disorders of sex development (DSDs) are a diverse group of conditions where the chromosomal, gonadal or anatomical sex can be atypical. The highly heterogeneous nature of this group of conditions often makes determining a genetic diagnosis challenging. Prior to next generation sequencing (NGS) technologies, genetic diagnostic tests were only available for a few of the many DSD-associated genes, which consequently had to be tested sequentially. Genetic testing is key in establishing the diagnosis, allowing for personalised management of these patients. Pinpointing the molecular cause of a patient's DSD can significantly impact patient management by informing future development needs, altering management strategies and identifying correct inheritance pattern when counselling family members. We have developed a 30-gene NGS panel, designed to be used as a frontline test for all suspected cases of DSD (both 46,XX and 46,XY cases). We have confirmed a diagnosis in 25 of the 80 patients tested to date. Confirmed diagnoses were linked to mutations in AMH, AMHR2, AR, HSD17B3, HSD3B2, MAMLD1, NR5A1, SRD5A2 and WT1 which have resulted in changes to patient management. The minimum diagnostic yield for patients with 46,XY DSD is 25/73. In 34/80 patients, only benign or likely benign variants were identified, and in 21/80 patients only variants of uncertain significance (VOUS) were identified, resulting in a diagnosis not being confirmed in these individuals. Our data support previous studies that an NGS panel approach is a clinically useful and cost-effective frontline test for patients with DSDs.

Is universal HLA-B*15:02 screening a cost-effective option in an ethnically diverse population? A case study of Malaysia

BACKGROUND

A strong association has been documented between HLA-B*15:02 and carbamazepine-induced severe cutaneous adverse reactions (SCARs) in Asians. Human leucocyte antigen testing is potentially valuable in many countries to facilitate early recognition of patient susceptibility to SCARs.

OBJECTIVES

To determine the cost-effectiveness of universal HLA-B*15:02 screening in preventing carbamazepine-induced Stevens-Johnson syndrome/toxic epidermal necrolysis in an ethnically diverse Malaysian population.

METHODS

A hybrid model of a decision tree and Markov model was developed to evaluate three strategies for treating newly diagnosed epilepsy among adults: (i) carbamazepine initiation without HLA-B*15:02 screening (current practice); (ii) universal HLA-B*15:02 screening prior to carbamazepine initiation; and (iii) alternative treatment [sodium valproate (VPA)] prescribing without HLA-B*15:02 screening. Base-case analysis and sensitivity analyses were performed over a lifetime time horizon. Incremental cost-effectiveness ratios were calculated.

RESULTS

Both universal HLA-B*15:02 screening and VPA prescribing were dominated by current practice. Compared with current practice, universal HLA-B*15:02 screening resulted in a loss of 0·0255 quality-adjusted life years (QALYs) at an additional cost of 707 U.S. dollars (USD); VPA prescribing resulted in a loss of 0·2622 QALYs at an additional cost of USD 4127, owing to estimated differences in antiepileptic treatment efficacy.

CONCLUSIONS

Universal HLA-B*15:02 screening is unlikely to be a cost-effective intervention in Malaysia. However, with the emergence of an ethnically diverse population in many other countries, this may render HLA-B*15:02 screening a viable intervention when an increasing proportion of the population is at risk and an equally effective yet safer antiepileptic drug is available.

Sugar-sweetened beverage intake and its associations with cardiometabolic risks among adolescents

BACKGROUND

Investigations on sugar-sweetened beverage (SSB) intake and cardiometabolic risks among Asians are scant.

OBJECTIVES

This study aimed to examine associations between SSB intake and cardiometabolic risks among Malaysian adolescents.

METHODS

Anthropometric data, blood pressure (BP), fasting blood glucose (FBG), lipid profiles and insulin levels measured involved 873 adolescents (aged 13 years). SSB intake, dietary patterns and physical activity level (PAL) were self-reported.

RESULTS

Mean SSB consumption was 177.5 mL day^-1 with significant differences among ethnicities (Malay, Chinese, Indians and Others) (p < 0.05). SSB intake was deleteriously associated with increased waist circumference, elevated triglycerides, FBG, insulin, insulin resistance and low HDL-cholesterol, independent of PAL, body mass index and dietary patterns. Significant U-shaped and inverse trends were noted between SSB intake and LDL-cholesterol and BP, respectively.

CONCLUSION

Sugar-sweetened beverage intake was unfavourably associated with cardiometabolic health outcomes among young adolescents. Concerted efforts towards healthy hydration are imperative to mitigate risk of cardiometabolic events.

Influence of Film Thickness and Annealing Temperature on Optical Properties of Nanostructured-TiO2 Thin Films Prepared by Sol–Gel Spin Coating Technique

TiO2 powder was found to be polycrystalline with rutile system. TiO2 films were deposited on quartz substrates by a sol–gel spin coating technique. X-ray diffraction and transmission electron microscope results have confirmed that the TiO2 films have nanostructure nature. It is found the crystallite size increased with annealing temperature. The optical constants of nanostructured TiO2 films were found to be independent of film thickness in the range from 100[Formula: see text]nm to 500[Formula: see text]nm. It is found that the optical constants and the dielectric constant of the thin films were all affected by annealing temperature. The existing allowed optical transitions in the as-deposited and annealed films were found to be direct and indirect transitions. Finally, the bandgaps of the as-deposited film were found to decrease with the annealing temperature.

Seroprevalence of Toxoplasma gondii infection among patients in Hospital Universiti Sains Malaysia

Toxoplasmosis is a worldwide endemic zoonotic infection caused by the obligate coccidian parasite Toxoplasma gondii. To assess the seroprevalence of T. gondii infection among hospital population of Hospital Universiti Sains Malaysia (HUSM), a cross-sectional study was conducted using serum samples of 102 participants. Samples were screened for the presence of anti-Toxoplasma IgG and IgM antibodies by enzyme-linked immunosorbent assay (ELISA). Only one sample recorded as IgM positive (0.98%) (1/102; 95% CI = 0.02- 5.34%), whereas 44.12% (45/102; 95% CI = 34.29-54.29%) were IgG positive. The study showed that seroprevalence of toxoplasmosis significantly differs between age groups (p < 0.001), with high prevalence of T. gondii infection (37.8%) among patients aged less than one month. Moreover, the study indicated a significant difference in the prevalence of toxoplasmosis between males and females. Additionally, a significant dependent relationships were observed (p = 0.003), when the reasons of toxoplasma serology request was considered, and the highest prevalence (59.6%) observed in congenital toxoplasmosis. In conclusion, the seroprevalence of toxoplasmosis in our study group was high. The study provides preliminary information about the seroprevalence and epidemiology of T. gondii infection among the hospital population in HUSM.

Conventional versus Doxorubicin-Eluting Beads Transarterial Chemoembolization for Unresectable Hepatocellular Carcinoma: a Tertiary Medical Centre Experience in Malaysia

BACKGROUND

Hepatocellular carcinoma (HCC) is a common cancer that is frequently diagnosed at an advanced stage. Transarterial chemoembolisation (TACE) is an effective palliative treatment for patients who are not eligible for curative treatment. The two main methods for performing TACE are conventional (c-TACE) or with drug eluting beads (DEB-TACE). We sought to compare survival rates and tumour response between patients undergoing c-TACE and DEB-TACE at our centre.

MATERIALS AND METHODS

A retrospective cohort study of patients undergoing either treatment was carried out from January 2009 to December 2014. Tumour response to the procedures was evaluated according to the modified Response Evaluation Criteria in Solid Tumors (mRECIST). Kaplan-Meier analysis was used to assess and compare the overall survival in the two groups.

RESULTS

A total of 79 patients were analysed (34 had c-TACE, 45 had DEB-TACE) with a median follow-up of 11.8 months. A total of 20 patients in the c-TACE group (80%) and 12 patients in the DEB-TACE group (44%) died during the follow up period. The median survival durations in the c-TACE and DEB-TACE groups were 4.9 ± 3.2 months and 8.3 ± 2.0 months respectively (p=0.008). There was no statistically significant difference noted among the two groups with respect to mRECIST criteria.

CONCLUSIONS

DEB-TACE demonstrated a significant improvement in overall survival rates for patients with unresectable HCC when compared to c-TACE. It is a safe and promising approach and should potentially be considered as a standard of care in the management of unresectable HCC.

Disparities in health-related quality of life among healthy adolescents in a developing country - the impact of gender, ethnicity, socio-economic status and weight status

BACKGROUND

Physical functioning and psychological resilience in adulthood is shaped during adolescence. Self-reported health-related quality of life (HRQoL) assessments during this life phase are important first-hand accounts of their well-being. This study aimed, firstly, to identify differences in HRQoL according to gender, ethnicity, socio-economic status and weight status; and secondly, to examine associations between weight status and HRQoL among an urban sample of multi-ethnic adolescents in Kuala Lumpur, Malaysia.

METHODS

A cross-sectional study involving 652 adolescents (aged 13 years) was conducted in Kuala Lumpur. Weight and height were measured. Body mass index z-scores were categorized according to the International Obesity Task Force criteria. HRQoL was assessed using the Malay version of the Pediatric Quality of Life Inventory 4.0 Generic Core Scales. Univariate analyses of differences in HRQoL according to gender, ethnicity (Malays, Chinese and Indians), maternal education level and weight status were performed. Complex samples general linear model was used to examine the associations between HRQoL and weight status, adjusted for confounders.

RESULTS

Female adolescents reported significantly lower emotional functioning scores (mean, 95% confidence interval: 59.25, 57.33-61.17). When the three main ethnic groups were studied, Malay adolescents scored significantly lower emotional functioning scores (59.00, 57.13-60.87) compared with their Chinese peers. Adolescents with tertiary-educated mothers reported lower emotional functioning scores (57.45, 53.85-61.06) compared with those with primary-educated mothers. Obese adolescents reported poorer HRQoL scores with significantly impaired physical and social functioning after controlling for confounders.

CONCLUSIONS

These findings detected disparities in HRQoL among the adolescents when gender, ethnicity, maternal education level and weight status were considered. Further studies should address these health inequalities by implementing gender-specific and culturally appropriate measures to attain optimal well-being and avoid potential burden of disease.

Vitamin D status and parathyroid hormone concentrations influence the skeletal response to zoledronate and denosumab

Studies suggest that optimal vitamin D status is required for the maximal effect of antiresorptive agents. We investigated the relationship between vitamin D status, serum parathyroid hormone (PTH) concentrations, and change in bone mineral density (BMD) following iv zoledronate and denosumab. We carried out a retrospective analysis of 111 patients, mean age 70 (SD 13) years, 89 women and 22 men, prescribed zoledronate and 43 postmenopausal women treated with denosumab for osteoporosis. We measured BMD at the lumbar spine (LS) and total hip (TH), serum 25 (OH) vitamin D, PTH, and bone turnover markers (plasma CTX, P1NP) at 1 year. In patients on zoledronate, BMD increased at the LS and TH (mean LS change [SEM] = 2.6 % [0.5 %], mean TH change = 1.05 % [0.5 %], p < 0.05). A significant increase in BMD was seen at the LS only in the denosumab group (p = 0.001). Significant decreases in CTX and P1NP were observed at 12 months in both treatment groups. At baseline and at 12 months, 34 % and 23 % of the patients on zoledronate had a serum vitamin D of <50 nmol/L, respectively. The mean PTH concentration in patients with 25 (OH) vitamin D <50 nmol/L was 44 ng/L (SEM 16.6). Patients with PTH concentration <44 ng/L had significantly higher increases in TH BMD compared to those with PTH >44 ng/L (zoledronate 1.9 [0.83] vs. -0.43 [0.81], p = 0.04; denosumab 4.1 [0.054] vs. -1.7 [0.04], p = 0.004). Optimal vitamin D status and PTH concentrations improve the skeletal response to zoledronate and denosumab.

G2677T polymorphism can predict treatment outcome of Malaysians with complex partial seizures being treated with Carbamazepine

Carbamazepine (CBZ) is used as the first line of treatment of complex partial seizures (CPS) in Malaysia. While this drug is known to be effective for the treatment of CPS, more than 30% of patients remain drug resistant to CBZ mono-therapy. We examined a possible relationship between patients' response to CBZ mono-therapy and the G2677T SNP of the ABCB1 gene. Three hundred and fourteen patients with CPS were recruited from the Neurology Department of the Kuala Lumpur Hospital, of whom 152 were responders and the other 162 were non-responders to CBZ mono-therapy. DNA was extracted from blood samples and real-time PCR was performed to detect the G2677T SNP of the ABCB1 gene. Results were described as genotype frequencies and compared by logistic regression analysis. Among the 152 responders, 74% had the GG genotype. However, among the 162 non-responders, 26.5% had the GT genotype and 39% had the TT genotype. There was a significant difference in genotype frequency (TT vs GG; odds ratio 4.70; 95% confidence interval, 2.70-8.20) between responders and non-responders. The presence of the T allele of the G2677T SNP appears to be a useful screening marker to determine if a patient is going to be resistant to CBZ as a single drug therapy in the treatment of CPS.

Protein expression in sera of patients with amoebic liver abscess (ALA): potential use of haptoglobin as a surrogate disease marker

The protein profile of serum samples from patients with amoebic liver abscess (ALA) was compared to those of normal individuals to determine their expression levels and to identify potential surrogate disease markers. Serum samples were resolved by two dimensional electrophoresis (2-DE) followed by image analysis. The up and down-regulated protein spots were excised from the gels and analysed by MS/MS. The concentration of three clusters of proteins i.e. haptoglobin (HP), α1-antitrypsin (AAT) and transferrin in serum samples of ALA patients and healthy controls were compared using competitive ELISA. In addition, serum concentrations of HP and transferrin in samples of patients with ALA and pyogenic liver abscess (PLA) were also compared. The results of the protein 2-DE expression analysis showed that HP cluster, AAT cluster, one spot each from unknown spots no. 1 and 2 were significantly up-regulated and transferrin cluster was significantly down-regulated in ALA patients' sera (p<0.05). The MS/MS analysis identified the unknown protein spot no.1 as human transcript and haptoglobin and spot no. 2 as albumin. Competitive ELISA which compared concentrations of selected proteins in sera of ALA and healthy controls verified the up-regulated expression (p<0.05) of HP and the down-regulated expression (p<0.01) of transferrin in the former, while there was no significant difference in AAT expression (p> 0.05). However, when ALA and PLA samples were compared, competitive ELISA showed significant increased concentration of HP (p<0.05) while transferrin levels were not different. In conclusion, this study showed that HP is a potential surrogate disease marker for ALA.

Detection of selected intestinal helminths and protozoa at Hospital Universiti Sains Malaysia using multiplex real-time PCR

Intestinal parasites are the causative agents of a number of important human infections in developing countries. The objective of this study was to determine the prevalence of selected helminths and protozoan infections among patients admitted with gastrointestinal disorders at Hospital Universiti Sains Malaysia, Kelantan, Malaysia using multiplex real-time PCR. In addition microscopic examination was also performed following direct smear, zinc sulphate concentration and Kato-Katz thick smear techniques; and the presence of protozoan parasites was confirmed using trichrome and acid-fast stains. Of the 225 faecal samples analysed, 26.2% were positive for intestinal parasites by the multiplex real-time PCR, while 5.3% were positive by microscopy. As compared to microscopy, the multiplex real-time PCR detected 5.8 and 4.5 times more positives for the selected helminth and protozoan infections respectively. Among the selected helminths detected in this study, hookworm was the most prevalent by real-time PCR, while Ascaris lumbricoides was detected the most by microscopy. Meanwhile, among the selected protozoa detected in this study, Entamoeba histolytica was the most prevalent by real-time PCR, however microscopy detected equal number of cases with E. histolytica and Giardia lamblia. This study showed that real-time PCR can be used to obtain a more accurate prevalence data on intestinal helminths and protozoa.

Genetic association of SNPs in the FTO gene and predisposition to obesity in Malaysian Malays

The common variants in the fat mass- and obesity-associated (FTO) gene have been previously found to be associated with obesity in various adult populations. The objective of the present study was to investigate whether the single nucleotide polymorphisms (SNPs) and linkage disequilibrium (LD) blocks in various regions of the FTO gene are associated with predisposition to obesity in Malaysian Malays. Thirty-one FTO SNPs were genotyped in 587 (158 obese and 429 non-obese) Malaysian Malay subjects. Obesity traits and lipid profiles were measured and single-marker association testing, LD testing, and haplotype association analysis were performed. LD analysis of the FTO SNPs revealed the presence of 57 regions with complete LD (D' = 1.0). In addition, we detected the association of rs17817288 with low-density lipoprotein cholesterol. The FTO gene may therefore be involved in lipid metabolism in Malaysian Malays. Two haplotype blocks were present in this region of the FTO gene, but no particular haplotype was found to be significantly associated with an increased risk of obesity in Malaysian Malays.

Lack of association of ABCB1 and PXR polymorphisms with response to treatment in epilepsy

It is proposed that overexpression of P-glycoprotein (P-gp), encoded by the ABC subfamily B member 1 (ABCB1) gene, is involved in resistance to antiepileptic drugs (AEDs) in about 30% of patients with epilepsy. Genetic variation and haplotype patterns are population specific which may cause different phenotypes such as response to AEDs. Although several studies examined the link between the common polymorphisms in the ABCB1 gene with resistance to AEDs, the results have been conflicting. This controversy may be caused by the effect of some confounders such as ethnicity and polytherapy. Moreover, expression of the ABCB1 gene is under the control of pregnane X receptor (PXR). Evidence showed that PXR gene contribute to the response to treatment. The aim of this study was to assess the association of ABCB1 and PXR genetic polymorphisms with response to the carbamazepine (CBZ) or sodium valproate (VPA) monotherapy in epilepsy. Genotypes were assessed in 685 Chinese, Indian, and Malay epilepsy patients for ABCB1 (C1236T, G2677T, C3435T) and PXR (G7635A) polymorphisms. No association between these polymorphisms and their haplotypes, and interaction between them, with response to treatment was observed in the overall group or in the Chinese, Indian, and Malay subgroups. Our data showed that these polymorphisms may not contribute to the response to CBZ or VPA monotherapy treatment in epilepsy.

A new record of Iranihindia martellata (Senior-White,1924) (Diptera: Sarcophagidae) from peninsular Malaysia and female identification using both morphology and DNA-based approaches

Iranihindia martellata (Senior-White, 1924) is recorded from peninsular Malaysia for the first time. Male and female specimens in the recent collections of forensically important sarcophagid flies were examined and identified based on morphology and DNA sequencing analysis. Male genitalia offer unambiguous species identification characteristics in the traditional taxonomy of flesh flies but the female flies are very similar to one another in general morphology. Female of I. martellata was determined by DNA sequencing (COI and COII) and PCR-RFLP (COI) analysis. Identified females were carefully examined and compared with the morphologically similar species, Liopygia ruficornis (Fabricius, 1794). Female genitalia are re-described and illustrated in this paper.

ABCB1 C3435T polymorphism and the risk of resistance to antiepileptic drugs in epilepsy: a systematic review and meta-analysis

OBJECTIVE

The C3435T, a major allelic variant of the ABCB1 gene, is proposed to play a crucial role in drug-resistance in epilepsy. The C/C genotype carriers reportedly are at higher risk of pharmacoresistance to AEDs, but only in some studies. The hypothesis of the C-variant associated risk and resistance to antiepileptic drugs (AEDs) has been hampered by conflicting results from inadequate power in case-control studies. To assess the role of C3435T polymorphism in drug-resistance in epilepsy, a systematic review and meta-analysis was conducted.

METHODS

Databases were obtained from the Cochrane Library, MEDLINE, EMBASE, major American and European conference abstracts, and www.google.my for genetic association studies up to February 2010. All the case-control association studies evaluating the role of ABCB1 C3435T in pharmacoresistance to AEDs were identified. The new definition of treatment outcome from International League Against Epilepsy (ILAE) was used for including studies for sub-analysis. To measure the strength of genetic association for the gene variant, the odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using models of both fixed- and random-effects for comparisons of the alleles and genotypes with co-dominant (C/C vs. T/T, C/T vs. T/T), dominant (C/C+C/T vs. T/T), and recessive (C/C vs. C/T+T/T) models in overall and in ethnicity subgroups. The 19 studies were selected for the next sub-analysis based on the new definition of drug-responsiveness and drug-resistance from ILAE. The same analysis was also performed for treatment outcome and ethnicity subgroups.

RESULTS

A total of 22 association studies including 3231 (47.8%) drug-resistant patients and 3524 (52.2%) drug-responsive patients or healthy controls (genotyped for C3435T) were pooled in this meta-analysis. The allelic association of ABCB1 C3435T with risk of drug-resistance was not significant under fixed-effects model, 1.06 (95% CI 0.98-1.14, p=0.12) and random-effects model, 1.10 (0.93-1.30, p=0.28) in overall and in the subgroup analysis by ethnicity. Similar results were also obtained for all genetic models in the stratified analyses by new definition of drug-resistance by ILAE and ethnicity subgroups. There was no publication bias.

CONCLUSION

We failed to show an association between the ABCB1 C3435T polymorphism and the risk of drug-resistance suggesting a revision in contribution of this polymorphism in the multi-drug transporters hypothesis of pharmacoresistance to AEDs in epilepsy.

Non-secretory multiple myeloma with diagnostic challenges

Non-secretory multiple myeloma (NSMM) is a rare variant of the classic form of multiple myeloma (MM). In NSMM, no monoclonal gammopathy can be detected in serum or urine by conventional techniques, making the diagnosis more difficult. We describe a 71-year-old man who had been diagnosed and treated for granulocytic sarcoma one year prior to his recent problems of progressive low-back pain of two months duration. Skeletal X-rays showed diffuse osteolytic lesions with multiple pathological fractures but there was no monoclonal gammopathy in the serum or urine. The biopsy of the lytic lesion on the upper part of the femur showed infiltration by abnormal plasma cells. A diagnosis of NSMM was made and he was treated with chemotherapy. The early diagnostic difficulty and the challenges faced regarding the case are discussed.

Establishing a reliable protocol to measure tongue sensation

The relationship between tongue sensation and tongue function for speech, mastication and deglutition are growing areas of interest among rehabilitative professionals. To determine the potential effect that sensation has on function, it is imperative that, first, reliable and valid measures of tongue sensation be established. The aim of this study was to develop a protocol to test tongue sensation across a spectrum of sensory functions that included two-point discrimination, light-touch discrimination, thermal sensation, texture recognition, oral stereognosis and taste recognition. Materials tested within each domain respectively included: (i) the MacKinnon-Dellon Disk-criminator, paperclip and caliper; (ii) the Semmes-Weinstein monofilament and cotton wisp; (iii) dental mirrors and glass test tubes; (iv) spheres of textured acrylic resin on rods; (v) acrylic resin forms with differing shapes on rods and (vi) salty, sweet, sour, bitter and neutral solutions. Materials were tested on 40 healthy subjects between the ages of 20 and 55. The results from this study indicated that thermal, texture and taste sensations appear robust for accuracy and discrimination. Two-point discrimination and light touch seem to be influenced by location of stimulation on the tongue and force applied, whereas stereognosis was influenced by stimulus complexity. The results of this study indicate that clinicians may choose instruments as practical as paperclips and test tubes for testing two-point discrimination and thermal sensation, respectively. For the other sensations, it may be important to use more sophisticated instrumentation to control variables of force, surface area stimulated and assessing sensations in graded steps.

Evaluation of two short tandem repeat multiplex systems for post-haematopoietic stem cell transplantation chimerism analysis

INTRODUCTION

The follow-up of chimerism status after allogeneic haematopoietic stem cell transplantation (HSCT) is essential to predict successful engraftment to assess the development of graft-versus-host disease, graft rejection and disease relapse. Analysis of short tandem repeats (STR) via polymerase chain reaction is frequently used for chimerism determination. However, most commercially-available kits have been designed for forensic purposes and may not be optimal for chimerism analysis. The present study aims to identify suitable STR markers for patient-donor pairs of predominantly Malay and Chinese ethnicity using two commercially-available forensic kits.

METHODS

We analysed six STR loci, namely, CSF1PO, TPOX, TH01 (using the CTT multiplex system) and F13A01, FESFPS and vWA (using the FFv multiplex system) in 33 human leukocyte antigen-matched Malaysian patient-donor pairs to determine the suitability of these two multiplex systems for chimerism analysis in our local population.

RESULTS

Informativity (different alleles in donor and recipient) of each individual locus was TH01 73 percent, vWA 73 percent, F13A01 52 percent, CSF1PO 61 percent, FESFPS 39 percent and TPOX 45 percent. When combined, the six STR loci were able to give chimerism results in 31 out of 33 (94 percent) cases.

CONCLUSION

We found that TH01 and vWA are informative STR targets for post-HSCT chimerism analysis in predominantly Malay and Chinese patient-donor pairs. The commercially-available kits will also permit laboratories without extensive molecular biology capabilities to perform DNA typing in HSCT recipients.

Phytoestrogens levels determination in the cord blood from Malaysia rural and urban populations

This study is a result of an analysis of free and conjugated phytoestrogens daidzein, genistein, daidzin, genistin and coumesterol in human cord blood plasma using LCMS. Cord blood was collected from urban and rural populations of Malaysia (n=300) to establish a simple preliminary database on the levels of the analyzed compounds in the collected samples. The study also aimed to look at the levels of phytoestrogens in babies during birth as this may have a profound effect on the developmental process. The sample clean up was carried out by solid-phase extraction using C18 column and passed through DEAE sephadex gel before analysis by LCMS. The mean concentrations of total phytoestrogens were daidzein (1.4+/-2.9 ng/ml), genistein (3.7+/-2.8 ng/ml), daidzin (3.5+/-3.1 ng/ml), genistin (19.5+/-4.2 ng/ml) and coumesterol (3.3+/-3.3 ng/ml). Distribution of phytoestrogen was found to be higher in samples collected from rural areas compared to that of urban areas.

The influence of CYP3A gene polymorphisms on cyclosporine dose requirement in renal allograft recipients

Cyclosporine is a substrate of cytochrome P-450 3A (CYP3A) subfamily of enzymes and characterized by a narrow therapeutic range with wide interindividual variation in pharmacokinetics. A few single-nucleotide polymorphisms detected in CYP3A genes have been shown to correlate significantly with the CYP3A protein expression and activity. We therefore postulated that these polymorphisms could be responsible for some of the interindividual variation in cyclosporine pharmacokinetics. The objective of our study is to determine correlation if any between single-nucleotide polymorphisms of CYP3A5 and CYP3AP1 on cyclosporine dose requirement and concentration-to-dose ratio in renal allograft recipients. Cyclosporine-dependent renal allograft recipients were genotyped for CYP3A5 A6986G and CYP3AP1 G-44A. The cyclosporine dosages prescribed and the corresponding cyclosporine trough levels for each patient were recorded so that cyclosporine dose per weight (mg/kg/day) and concentration-to-dose ratio (C(0)/D, whereby C(0) is trough level and D is daily dose per weight) could be calculated. A total of 67 patients were recruited for our study. The dose requirement for 1, 3, and 6 months post-transplantation ranged 2.3-11.4, 1.0-9.0, and 1.4-7.2 mg/kg/day, respectively. Patients with *1*1*1*1 (n=5) CYP3A5- and CYP3AP1-linked genotypes needed higher dose of cyclosporine compared to patients with *1*3*1*3 (n = 27) and *3*3*3*3 (n = 33) linked genotypes in months 3 and 6 post-transplantation (P < 0.016). The identification of patients with *1*1*1*1 by CYP3A5 and CYP3AP1 genotyping may have a clinically significant and positive impact on patient outcome with reduced rejection rate by providing pretransplant pharmacogenetic information for optimization of cyclosporine A dosing.

Alopecia areata treatment with a phototoxic dose of UVA and topical 8-methoxypsoralen

Twenty-five patients with alopecia totalis (AT) or alopecia universalis and 124 patients with alopecia areata (AA) were treated with photochemotherapy, combining topical 8-methoxypsoralen (8-MOP) with UV irradiation of the scalp at a phototoxic dose. The mean energy required was 15 J/cm2 for AA and 42 J/cm2 for AT. Ninety-four patients had multiple bald patches and 12 with AT had complete or > 50% hair regrowth. Positive treatment results did not seem to depend on the age of onset or the duration of the disease. Few side-effects of topical psoralens plus UVA (PUVA) treatment were noted, except a for few days of slight erythema caused by the high dose of UV.

Genetic polymorphism of cytochrome P450 2C19 in healthy Malaysian subjects

AIMS

Impaired S-mephenytoin 4'-hydroxylation is a well-described genetic polymorphism affecting drug metabolism in humans. Although ethnic differences in its distribution of polymorphism has been described, it is not known whether there is an ethnic heterogeneity of the structure and expression of the CYP2C19 enzyme in the Malaysian population.

METHODS

Study subjects were 142 healthy, unrelated Malaysians aged 18-29 years. Baseline omeprazole and 2-h postingestion omeprazole and 5'-hydroxyomeprazole concentrations were measured for CYP2C19 phenotype determination. Identification of CYP2C19 genotypes was performed with the use of polymerase chain reaction.

RESULTS

Phenotyping of CYP2C19 revealed that the prevalence of poor metabolizers (PMs) in the Malaysian population was 14.1%, whereas prevalence of PMs in genotyping was 12.6%. The PM genotypic prevalence rate was 5.6% in Malays, 19.1% in Chinese and 10.0% in Indian subjects. There were significant differences in PM genotypic prevalence rates among the three primary ethnic groups (P < or = 0.05).

CONCLUSIONS

Phenotyping and genotyping revealed significant differences in the prevalence rates among the three ethnic groups in Malaysia, with Chinese recording highest prevalence.

Growing dural sinus malformation with associated developmental venous anomaly, multiple cavernomas and facial venous malformation in an infant. An associated disease or a disease spectrum?

SUMMARY

This is an unusual case report of an infant, who initially presented with a facial haemangioma and was later diagnosed to have a dural sinus malformation (DSM) involving the torcula. The DSM increased in size lateralising to the right transverse sinus at three months of age. Postnatal enlargement of the dural sinus has not been described before suggesting a delay in the maturation of the dural sinus which normally would occur antenatally. There was a further association with a complex developmental venous anomaly (DVA) draining the right cerebral hemisphere into the deep cerebral vein and multiple cavernous malformations. The DVA was not clearly demonstrated at age one month but was more obvious at age three months. This would be the first reported case of DSM associated with a DVA. Increasing venous hypertension probably contributed to the poor opacification of the DVA on follow-up angiography at age six months and to the haemorrhagic changes within the cavernomas on magnetic resonance imaging (MRI). The therapeutic goal was to correct venous hypertension by partially embolising the dural shunts to remodel the cerebral vasculature and preserve the patent sinus. The treatment strategy and possible link between the complex disease entities presented in this infant are discussed. Despite these attemps, the lesion continued to grow compressing the posterior fossa structures. The infant died at nine months of age.

Evidence of an interaction between nifedipine and nafcillin in humans

AIMS

Nafcillin (Wyeth Laboratories, Philadelphia, PA, USA) has been reported to induce the metabolism of cyclosporin and warfarin, which are known substrates of cytochrome P-450 (CYP). However, there has not been any report to date on its possible interaction with nifedipine, an index substrate of the enzyme, CYP3A4.

METHODS

Nine healthy normotensive subjects participated in this randomized placebo-controlled two-way crossover study examining the effects of 5 days' pretreatment of nafcillin 500 mg or placebo four times daily on the pharmacokinetics of an oral dose of nifedipine 10 mg. Plasma nifedipine concentrations were measured by gas chromatography-mass spectro.

RESULTS

The area under the plasma nifedipine concentration-time curve (AUC0-alpha) in nafcillin-pretreated subjects (80.9 +/- 32.9 micro g l-1 h-1) was significantly decreased compared with subjects who received only nifedipine (216.4 +/- 93.2 micro g l-1 h-1) (P < 0.001). Total plasma clearance of nifedipine (CL/F) was significantly increased with nafcillin pretreatment (138.5 +/- 42.0 l h-1 vs 56.5 +/- 32.0 l h-1) (P < 0.002).

CONCLUSIONS

The results show that nafcillin pretreatment markedly increased the clearance of nifedipine and suggest that nafcillin is a potent inducer of CYP enzyme.

Linkage of a medium sized Scottish autosomal dominant retinitis pigmentosa family to chromosome 7q

Retinitis pigmentosa is a group of hereditary retinopathies which is both clinically and genetically heterogeneous. Autosomal dominant (ADRP), autosomal recessive (ARRP), and X linked recessive (XLRP), as well as digenic forms of inheritance have been reported. ADRP has been linked to 3q, 6p, 7p, 7q, 8cen, 17p, 17q, and 19q. Three unrelated ADRP families have been reported to show linkage to 7q. We tested a Scottish ADRP family with microsatellite markers mapping within the 7q31-q35 region, and found three markers (D7S487, D7S514, D7S530) showing statistically significant evidence of linkage. A maximum two point lod score of 3.311 at 0% recombination was obtained for D7S514.

Probing the functions of endogenous lectins: effects of a monoclonal antibody against the neural crest-stage lectin of Xenopus laevis on trunk development

Trunk neural crest of Xenopus laevis has been confronted prior to migration with whole or fragments of a monoclonal antibody raised against the carbohydrate-binding site of the endogenous neural crest-stage galactoside binding lectin (Milos et al.: Anat. Embryol., 182:319-327 '90). External fin formation was inhibited in confronted regions but extensive internal matrix develops suggesting interiorization of fin tissue. In the regions of missing fin, the myotomes overgrew the neural tube and dorsal root ganglion neuronal numbers became more variable. Melanophore numbers in regions of missing fin did not change but a significantly greater proportion of the pigment cells localized on the muscle surface that had overgrown the neural tube suggesting that the pigment cell population redistributed itself to occupy a greater myotomal area.

[Adrenal myelolipoma: a new case. Review]

We report a case of symptomatic myelolipoma with a good evolution at three and a half years' follow up. The clinical features and the diagnosis of this tumor type are discussed. In this case, as in most cases, CT proved to be the most useful in making the diagnosis. Like most of the cases, the patient was middle aged, obese and hypertensive. The etiology, pathogenesis, clinical features and diagnosis of this disease entity are reviewed. The treatment modalities utilized according to the specific features of each case are discussed.