1.Vertical distribution of Aedes mosquitoes in multiple storey buildings in Selangor and Kuala Lumpur, Malaysia
Lau, K.W ; Chen, C.D ; Lee, H.L. ; Izzul, A.A ; Asri-Isa, M ; Zulfadli, M. ; Sofian-Azirun, M.
Tropical Biomedicine 2013;30(1):36-45
The aim of the present study was to determine the vertical distribution and
abundance of Aedes mosquitoes in multiple storey buildings in Selangor and Kuala Lumpur,
Malaysia. Ovitrap surveillance was conducted for 4 continuous weeks in multiple storey
buildings in 4 residential areas located in Selangor [Kg. Baiduri (KB)] and Kuala Lumpur
[Student Hostel of University of Malaya (UM), Kg. Kerinchi (KK) and Hang Tuah (HT)]. The
results implied that Aedes mosquitoes could be found from ground floor to highest floor of
multiple storey buildings and data from different elevation did not show significant difference.
Ovitrap index for UM, KB, HT and KK ranged from 0 – 29.17%, 0 – 55.56%, 8.33 – 83.33% and
0 – 91.17% respectively. Aedes aegypti and Aedes albopictus were found breeding in HT, KK
and KB; while only Ae. albopictus was obtained from UM. The results indicate that the
invasion of Aedes mosquitoes in high-rise apartments could facilitate the transmission of
dengue virus and new approaches to vector control in this type of residential area should be
developed.
2.Evaluation of insect growth regulators, temephos and Bacillus thuringiensis israelensis against Aedes aegypti (L) in plastic containers
Lau, K.W. ; Chen, C.D. ; Sofian-Azirun, M.
Tropical Biomedicine 2015;32(4):684-692
The residual activities of 5 insect growth regulators (IGRs) were studied and
compared to operational dosage of temephos (1 mg/L) and Bacillus thuringiensis israelensis
(Bti) (0.008 mg/L). The IGRs, temephos and Bti were applied into plastic containers containing
5 litres of water. Thirty Aedes aegypti larvae were added into each container weekly. Efficacy
of these IGRs were evaluated for effective duration of each dosage and the percentage of
emergence inhibition (EI). An end-point of EI/mortality > 50% was considered to be effective.
Pyriproxyfen possessed the longest residual activity in both indoor (43 weeks) and outdoor
(26 weeks) conditions, followed by temephos (26 weeks in indoor and 16 weeks in outdoor).
Although the residual activity of Bti in indoor lasted 8 weeks which was longer than cyromazine
and diflubenzuron; however, it was least effective in outdoor which only lasted 2 weeks. This
study revealed that pyriproxyfen possessed good residual effect among test IGRs compared
to temephos and Bti. The use of IGRs can be an alternative long-term control measure in
stagnant water body.
3.BRIEF HYPOXIA PRECEDING E. COLI BACTEREMIA DOWNREGULATES HEPATIC TNF-α PRODUCTION
Zhoumou CHEN ; Bingyin SHI ; Subbash TODI ; Cheryl JOHANNS ; M. GEORGE ;
Journal of Pharmaceutical Analysis 1999;11(1):40-44
Hepatic TNF-α production following gram-negative bacteremia or hypovolemic shock predisposes to acute lung injury. However, TNF-α expression may be modified by the manner in which the hepatic O2 supply is reduced and equally important, its timing relative to bacteremia. Brief secondary hypoxic stress of buffer-perfused rat livers downregulates E. Coli (EC)-induced TNF-α expression whereas low-flow ischemia preceding EC increases subsequent TNF-α production owing to reactive O2 species (ROS). Here we determined whether 30 min of constant-flow hypoxia preceding 109 intraportal EC likewise increases antigenic and bioactive TNF-α protein concentrations during reoxygenation via production of ROS. Multiple groups (n=38) were studied over 180 minutes, circulation antigenic TNF-α decreased in H/R+EC vs. EC controls (1 939±640 vs. 12 407±2 476 μg/L at t=180 min; P<0.01, along with TNF-α bioactivity). TNF-α protein were not restored to control levels in ALLO+H/R+EC. Thus, EC-induced hepatic TNF-α production and export is strongly O2-dependent in intact liver regardless of the generation of ROS or the sequence of bacteremia and modest hypoxic stress.
4.Quantifying the duration of the preclinical detectable phase in cancer screening: a systematic review
Sandra M. E. GEURTS ; Anne M. W. M. AARTS ; André L. M. VERBEEK ; Tony H. H. CHEN ; Mireille J. M. BROEDERS ; Stephen W. DUFFY
Epidemiology and Health 2022;44(1):e2022008-
OBJECTIVES:
The aim of this study was to provide an overview of published mathematical estimation approaches to quantify the duration of the preclinical detectable phase (PCDP) using data from cancer screening programs.
METHODS:
A systematic search of PubMed and Embase was conducted for original studies presenting mathematical approaches using screening data. The studies were categorized by mathematical approach, data source, and assumptions made. Furthermore, estimates of the duration of the PCDP of breast and colorectal cancer were reported per study population.
RESULTS:
From 689 publications, 34 estimation methods were included. Five distinct types of mathematical estimation approaches were identified: prevalence-to-incidence ratio (n=8), maximum likelihood estimation (n=16), expectation-maximization algorithm (n=1), regression of observed on expected (n=6) and Bayesian Markov-chain Monte Carlo estimation (n=5). Fourteen studies used data from both screened and unscreened populations, whereas 19 studies included only information from a screened population. Estimates of the duration of the PCDP varied between 2 years and 7 years for breast cancer in the Health Insurance Plan study (annual mammography and clinical breast examinations in women aged 40-64 years) and 2 years and 5 years for colorectal cancer in the Calvados study (a guaiac fecal occult blood test in men and women aged 45-74 years).
CONCLUSIONS
Different types of mathematical approaches lead to different estimates of the PCDP duration. We advise researchers to use the method that matches the data available, and to use multiple methods for estimation when possible, since no method is perfect.
5.Safety and effectiveness of insulin lispro mix 25/75 among Filipino patients with type 1 or type 2 diabetes mellitus: A post-marketing surveillance study.
Roa Mary Ann ; Cruz Cecille ; Chen Yun ; Chen Steve C ; Edralin Diana M
Philippine Journal of Internal Medicine 2015;53(3):1-8
BACKGROUND: Diabetes mellitus (DM) is a major cause of morbidity and mortality in the Philippines. Improvement in hemoglobin A1c (HbA1c) remains below recommended targets for Filipino patients. Safe and effective therapies are needed for this population.
OBJECTIVE: To investigate treatment-emergent adverse events (TEAEs) and change in HbA1c among Filipino patients with DM treated with insulin lispro mix 25/75 in a real-world setting.
MATERIALS AND METHODS: This was a prospective, non-interventional, post-marketing surveillance study among 459 Filipinos aged 18 years or older with type 1 or 2 DM. Patients were treated with insulin lispro mix 25/75 according to the approved label, as prescribed by the investigators, and observed for 12 weeks. Occurrence of all TEAEs and change in HbA1c from baseline to final visit were reported.
RESULTS: Mean (SD) treatment duration was 12.93 (5.7) weeks, and mean total daily dose was 0.62 (0.29) units/kg. Eighteen patients (3.9%) experienced 23 TEAEs, the majority of which were mild. None were reported to be related to treatment. No serious TEAEs or hypoglycemic episodes were reported. Mean (95% confidence interval) HbA1c was significantly reduced by -2.03% (-2.19%, -1.87%), and 36.3% of patients achieved HbA1c <7.0% at 12 weeks.
CONCLUSION: In this observational study, no treatmentrelated safety signals using insulin lispro mix 25/75 were detected among Filipino diabetic patients. HbA1c was significantly reduced in Filipino patients with DM at 12 weeks.
Human ; Male ; Female ; Middle Aged ; Adult ; Insulin Lispro ; Hemoglobin A, Glycosylated ; Hypoglycemia ; Diabetes Mellitus ; Hypoglycemic Agents
6.Eldepryl prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced nigral neuronal apoptosis in mice
M GUO ; SD CHEN ; ZG LIU ; HZ CHEN
Chinese Medical Journal 2001;114(3):240-243
Objective To study the apoptotic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on the nigral dopaminergic neurons of mice and 1-methyl-4-phenylpyridium ion (MPP+) on pheochromocytoma (PC12) cells, as well as the antagonism of Eldepryl against MPTP's apoptotic effect. Methods Three groups of C57BL mice were treated with MPTP, Eldepryl plus MPTP and normal saline, respectively, for 7 days before performing TUNEL (terminal deoxyneucleotidyl transferase-mediated dUTP-x nick end labeling) and FACS (fluorescence activated cell sorting) analyses of neuronal apoptosis in the substantia nigra. The same tests were employed in cell culture to examine apoptosis in PC12 cells treated with MPP+, MPTP or PBS. Results Intraperitoneal administration of MPTP 30*!mg/kg could induce nigral apoptosis, and oral use of Eldepryl prior to MPTP treatment could completely prevent the nigral apoptosis caused by MPTP. MPP+, an intermediate metabolite of MPTP, could lead to the apoptosis of PC12 cells, whereas MPTP itself had no such effect on PC12 cells. Conclusions The experiment indicated that the neurotoxin, MPTP, might cause the death of nigral neurons through a mechanism of apoptosis and this effect might be mediated by its bioactive intermediate metabolite MPP+. Eldepryl could protect the neurotoxicity from MPTP.
7.Optimization of the Extraction Technology of Total Flavonoids from Combretum alfrdii
Jinzhou LI ; Yong CHEN ; Zijun CHEN ; Peiqun LYU ; Yugang LIN ; Huimin LU ; Yanru HUANG
China Pharmacy 2019;30(20):2807-2812
OBJECTIVE: To establish the method for content determination of total flavonoids from Combretum alfrdii, and to optimize the extraction technology of total flavonoids from C. alfrdii. METHODS: Using aluminium trichloride as, chromogenic agent, UV spectrum was adopted to determine the content of total flavonoids from C. alfrdii. Based on single factor test, ethanol volume fraction, material-liquid ratio, extraction time, extraction temperature and times were selected as investigation factors, and the content of total flavonoids was selected as response value, Plackett-Burman design was used to screen the factors that had significant influence on the content of total flavonoidsfrom C. alfrdii. Then steepest climbing test was adopted to confirm the optimum valuing range; the extraction technology of total flavonoids was optimized by Box-Behnken response methodology. RESULTS: The linear range of total flavonoids were 0.012-0.036 mg/mL (r=0.999 9); RSDs of precision, stability and repeatability tests were less than 3%; the recovery ranged from 92.98% to 99.86% (RSD=2.71%, n=6). The optimal extraction technology included that 60% ethanol, material-liquid ratio of 1 ∶ 34 (g/mL), extracting for 3 times, lasting for 60 min, extraction temperature of 80 ℃. Under this technology, average content of total flavonoids from C. alfrdii was 2.71% (RSD=1.69%, n=6), and the relative error was 2.65% compared with predicted value of the model (2.64%). CONCLUSIONS: Established method is stable and reproducible, and can be used for content determination of total flavonoids from C. alfrdii. The optimized extraction method is stable and feasible.
8.Sample Preparation and Imaging of Single Adenovirus Particle Using Atomic Force Microscopy in Liquid.
Yan LIANG ; Li CHEN ; Mariska G M van ROSMALEN ; Gijs J L WUITE ; Wouter H ROOS
Chinese Journal of Virology 2015;31(6):601-606
Atomic force microscopy (AFM), as a sophisticated imaging tool with nanoscale resolution, is widely used in virus research and the application of functional viral particles. To investigate single viruses by AFM in a physiologically relevant environment (liquid), an appropriate surface treatment to properly adhere the viruses to the substrate is essential. Here we discuss hydrophobic treated glass coverslips as a suitable substrate for the adhesion of single adenovirus particle (Adenovirus type 5 F35, Ad5F35) when studied with AFM in liquid. From the high resolution AFM images, the orientation of the adhered virus particles can be distinguished. Furthermore, the particles exhibit the expected height of -90 nm. This illustrates that the viruses adhere to the substrate firmly without large deformations. Hence, the described method works well on (fragile) viruses. The described experimental approach can be widely used for AFM studies in liquid of virus structure and mechanics as well as for investigating the interaction of viruses with cellular receptors.
Adenoviridae
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chemistry
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Imaging, Three-Dimensional
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Microscopy, Atomic Force
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methods
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Virion
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chemistry
9.A review on the clinical implementation of respiratorygated radiation therapy
CB Saw ; E Brandner ; R Selvaraj ; H Chen ; M Saiful Huq ; DE Heron
Biomedical Imaging and Intervention Journal 2007;3(1):1-8
Respiratory-gated treatment techniques have been introduced into the radiation oncology practice to manage target or organ motions. This paper will review the implementation of this type of gated treatment technique where the respiratory cycle is determined using an external marker. The external marker device is placed on the abdominal region between the xyphoid process and the umbilicus of the patient. An infrared camera tracks the motion of the marker to generate a surrogate for the respiratory cycle. The relationship, if any, between the respiratory cycle and the movement
of the target can be complex. The four-dimensional computed tomography (4DCT) scanner is used to identify this
motion for those patients that meet three requirements for the successful implementation of respiratory-gated treatment technique for radiation therapy. These requirements are (a) the respiratory cycle must be periodic and maintained during
treatment, (b) the movement of the target must be related to the respiratory cycle, and (c) the gating window can be set sufficiently large to minimise the overall treatment time or increase the duty cycle and yet small enough to be within the gate. If the respiratory-gated treatment technique is employed, the end-expiration image set is typically used for treatment planning purposes because this image set represents the phase of the respiratory cycle where the anatomical
movement is often the least for the longest time. Contouring should account for tumour residual motion, setup
uncertainty, and also allow for deviation from the expected respiratory cycle during treatment. Respiratory-gated intensity-modulated radiation therapy (IMRT) treatment plans must also be validated prior to treatment. Quality assurance should be performed to check for positional changes and the output in association with the motion-gated technique. To avoid potential treatment errors, radiation therapist (radiographer) should be regularly in-serviced and made aware of the need to invoke the gating feature when prescribed for selected patients.
10.Determining The Cut-Off Score For A Malay Language Version Of The Centre For Epidemiologic Studies Depression Scale (CESD)
Siti Raudzah Ghazali ; Ask Elklit ; Rekaya Vincent Balang ; M Ameenudeen Sultan ; Yoke Yong Chen
ASEAN Journal of Psychiatry 2014;15(2):146-152
Objective: The objective of this study is to determine the optimal cut-off score for the Centre for Epidemiologic Studies Depression scale (CESD) according to Malaysian adolescent norms. Methods: This is a cross-sectional study. Nine hundred and thirty-one adolescents aged 13 to 17 years-old completed the CESD and Hopkins Symptom Checklist-depression scale (HSCL-depression). Results:
Results from the receiver operating characteristic (ROC) curve, kappa coefficients and odds ratio analysis showed that CESD cut-off score of 27 was suitable to be used according to Malaysian norms, demonstrating a specificity of 93%. Conclusion: The findings suggest a cut-off score 27 should be used for screening of depression for Malaysian adolescents using the CESD.