Volume 5 (2011): Edition 4 (August 2011)

Background: Transcription factors of the Forkhead box O (Fox O) family have important roles in cellular proliferation, apoptosis, differentiation, and stress resistance. In pancreatic β-cells, FoxO1 protein plays an important role in β-cells development. The molecular mechanism of transcriptional regulation of basal FoxO1 gene expression in pancreatic β-cells is not fully understood.

Objectives: Explore the potential transcription factors regulating FoxO1 promoter activity using pancreatic β-cell line (RINm5F cells)

Methods: Promoter screening method, luciferase reporter gene analysis, transient expression assay system, and deletion analysis of a -974/-18 bp 5’ upstream region of the mouse FoxO1 gene were used in this study.

Results: An inhibition domain (-974/-321) and an activation domain (-321/-18) was identified through deletion analysis of a -974/-18 bp 5’ upstream region of the mouse FoxO1 gene. Using the promoter screening method, several transcription factors were selected. Luciferase reporter studies showed that these factors could regulate FoxO1 promoter activity in RINm5F cells. Among these factors, cAMP response-element binding protein (CREB) could positively regulate FoxO1 promoter activity. Signal transducer and activator of transcription 1 (STAT1) played a negative role on FoxO1 promoter. In addition, ETS oncogene family member Elk-1 did not affect the FoxO1 promoter activity.

Conclusion: Two transcription factors (CREB and STAT1) could effectively regulate the mouse FoxO1 gene promoter activity.

Background: Chemotherapy-induced nausea and vomiting remains a significant problem for children with leukemia. There is limited evidence to support using prophylactic antiemetic prior to the administration of intrathecal chemotherapy.

Objective: Determine whether vomiting and nausea associated with intravenous ketamine and intrathecal chemotherapy may be reduced by the addition of prophylactic dexamethasone in children.

Method:A randomized, double-blinded, crossover, placebo-controlled trial was completed in 33 children receiving intrathecal chemotherapy with methotrexate and ketamine sedation at Pharmongkutklao Hospital. Patients were randomly assigned in a double-blinded fashion to receive one of two interventions during the first period, either an infusion of normal saline or intravenous dexamethasone at 0.25 mg/kg/dose. Each patient acted as his or her own control, and each patient was studied at two time-points.

Results: Period effect, sequence effect, and carry over effect were not demonstrated. The absolute risk reduction of vomiting was significantly greater after infusion of dexamethasone than after placebo at 33.3 % (p=0.02). The number needed to treat was three to prevent one episode of vomiting. Fifteen patients in the treatment group reported nausea versus 26 patients in the placebo group (p= 0.007). In the group of patients treated with dexamethasone, five required antiemetic vs. 16 of those receiving placebo (p=0.02). There was no complication from dexamethasone.

Conclusion: Intravenous dexamethasone reduced vomiting associated with intrathecal chemotherapy and ketamine sedation, without significant side-effects. It may be recommended a reasonable option before intrathecal chemotherapy

Background: Asymmetric dimethylarginine (ADMA) induces endothelial cell barrier dysfunction via cytoskeleton activation and contraction. It is supposed that activated p38 mitogen-activated protein kinase (MAPK) would trigger the formation of stress fibers and increase cellular permeability.

Objective: Explore p38 MAPK as a potentially important enzyme in ADMA-mediated endothelial cell contractile response and permeability change.

Methods: Human umbilical endothelial cells (HUVECs) were cultured, where ADMA and/or SB203580 (the specific inhibitor of p38MAPK) were used to stimulate HUVECs. Immunofluorescent staining was carried out to examine the expression and distribution of F-actin, flow cytometry was used to quantify F-actin, and Transwell was applied to test cellular permeability with FITC-labelled human serum albumin (HSA). Scanning electronic microscopy (SEM) was utilized to observe the changes of intercellar contact.

Results: ADMA induced significant p38MAPK activation in a dose-dependent manner, which correlated with increased stress fibers. SB-203580 attenuated the formation of actin stress fiber and the increase of cellular permeability induced ADMA in the HUVECs (p<0.01, LSCM; p<0.01, cytometry; p<0.05, Transwell). Widened intercellular space induced by ADMA was detected and could be inhibited by SB-203580 (SEM). SB-203580 alone had no effect on cytoskeleton and cellular permeability.

Conclusion: p38MAPK activation participated in cytoskeleton and cellular permeability changes induced by ADMA in HUVECs.

Background: Cardiomyocyte hypertrophy is a common complication of hypertension, and is recognized as an important risk factor for cardiovascular diseases. Up to now, no study has been made on the effects of telmisartan on Ang II-induced cardiomyocyte hypertrophy.

Objective: Investigate the effects of telmisartan on angiotensin II-induced cardiomyocyte hypertrophy and the phosphorylation of extracellular signal-regulated kinase (p-ERK_1/2) in rat-cultured cardiomyocytes.

Methods: Rat myocardial cells were cultured. Beating rates of the cardiomyocytes, cell volumes, total protein contents, protein synthesis rates, and ERK activity were measured. The phosphorylation of p-ERK_1/2 was analyzed by Western blot.

Results: Treatment of cultured cardiomyocytes with telmisartan inhibited angiotensin II-induced increases in cell volume, beating rate, total protein content and protein synthesis rate. Telmisartan markedly inhibited p-ERK_1/2 phosphorylation in a dose- and time-dependent manner.

Conclusion: Telmisartan could suppress cardiomyocyte hypertrophy induced by angiotensin II. The mechanism might be related to the inhibition of p-ERK_1/2 phosphorylation.

Background: The Work-Related Quality of Life Scale (WRQLS) was developed for health-care workers in England but might be useful, if valid, in other parts of the world or for other professions.

Objective: We test the construct validity and reliability of the WRQLS as applied to nurses in Singapore.

Methods: A descriptive study was undertaken in 2009 on a sample of 811 nurses at the National University Hospital (NUH) of Singapore who had at least one year’s work experience. The WRQLS was used in order to test its construct validity. Exploratory factor analysis was performed to reduce the factors used to determine WRQLS variance. The Pearson’s correlation was used to evaluate the relationship between the WRQLS and the 12-item short form health survey (SF-12) in order to substantiate conclusions regarding construct validity while Cronbach’s alpha was calculated to test WRQLS reliability.

Results: The median age of the respondents was 31 (IQR=12) and the majority were female (96.9%). The median duration of work experience was seven years (IQR=10). Following the exploratory factor analysis, a five-factor model with 22 items was selected, including; 1) job and career satisfaction, 2) general well-being, 3) home-work interface, 4) stress at work, and 5) working conditions. The correlation coefficient showed a moderate relationship between the WRQLS and mental component scale (MCS-12) (r=0.495); and a weak relationship between the WRQLS and physical component scale (PCS-12) (r=0.149). The Cronbach’s alpha revealed good reliability (r=0.92).

Conclusion: The WRQLS test among nurses in Singapore showed good construct validity and reliability. It could be useful in a working environment in Asia but further testing might be warranted.

Background: Salbutamol is a β²-selective adrenoceptor agonist used as a bronchodilator. Delivery by inhalation has many advantages over oral dosage for the treatment of asthma. It offers rapid onset of action with low systemic side effects.

Objective: Evaluate the relationship of in vitro particle size characteristics and pharmacodynamics of formulations of inhaled salbutamol dry powder.

Methods: Three formulations contained micronized salbutamol and a lactose carrier with different size ranges (40- 80, 20-40, and 10-20 μm for formulations 1, 2, and 3, respectively). Following formulation of the drug, resultant powders were characterized using scanning electron microscopy and the aerosolization performance determined using an Andersen Cascade Impactor analysis. A high-performance liquid chromatography method was used for measuring the salbutamol drug content. The in vivo pharmacodynamics of the formulations was monitored in 12 healthy and 12 asthmatic volunteers.

Results: The percentage of the fine particle fractions (FPF) for formulations 1, 2, and 3 were 24.87±0.52%, 33.82±3.80%, and 41.50±2.86%, respectively. The mass median aerodynamic diameters (MMAD) were around 3 μm for all formulations. The pharmacodynamic parameters, forced vital capacity (FVC), forced expiratory volume in one second (FEV₁) and mid expiratory flow (FEF_25-75), were indices for evaluation of the bioavailability of the bronchodilatory drug. All formulations improved the FEF_25-75 value in asthmatics, while FVC and FEV₁ were not altered.

Conclusion: The formulations of salbutamol dry powder aerosols with a fine lactose carrier produced a high deposition in the lower regions of the respiratory tract. Although the FEF_25-75 value in asthmatics was improved, the value did not correlate well with the FPF of the salbutamol dry powder.

Background: The use of sedation for gastrointestinal endoscopy (GIE) procedures in elderly patients has been established as a safe and effective technique. However, it is still uncertain whether the situation is valid for Asians.

Objective: Evaluate the outcome of intravenous sedation (IVS) for GIE procedures in very elderly patients (>86 years old) in Thailand and compare the clinical efficacy of IVS between very elderly and those younger (<86 years old)

Methods: We undertook a retrospective review of the sedation service records of patients who underwent GIE procedures between 2007 and 2008 at Siriraj Hospital, Thailand. All sedations were administered by anesthetic personnel in the endoscopy room. The cohort was divided into three groups, <65 years old (group 1), 65-85 years old (group 2), and >86 years old (group 3).

Results: Sedation was provided for 1,779 patients (965, 687, and 127 patients in group 1, 2, and 3, respectively) in 2,061 GIE procedures. Fentanyl, midazolam and propofol were the most common IVS drugs used in all three groups. Patients in group 3 required lower mean doses of these intravenous sedatives than those in group 1 or 2 (p <0.001). Mean procedure time in group 3 was longer than in group 1 or 2 (p=0.010). Adverse events in group 3 occurred more frequently when compared to group 1 or 2 (p <0.001). Transient hypotension was the main complication across all aged groups.

Conclusion: IVS for GIE procedure in very elderly patients was associated with higher minor advance events but relatively safe and effective when carried out by trained anesthetic personnel with appropriate monitoring and dose adjustment.

Background: Geriatric syndromes are a series of clinical conditions in the elderly that do not fit into distinct categories. They affect the quality of life of a patient and are associated with disability.

Objectives: This study determined the prevalence of geriatric syndromes in an Internal Medicine Outpatient setting. It compared the prevalence of each geriatric syndrome when using a comprehensive geriatric assessment versus the routine medical assessment.

Methods: One hundred twenty elderly patients of the Internal Medicine Outpatient Clinic of Srinagarind Hospital Medical School were randomly reviewed between January 2008 and May 2010. Information on baseline characteristics and the presence of a geriatric syndrome was collected. Data for 50 patients assessed using a comprehensive geriatric assessment were reviewed prospectively and data for 70 patients assessed by a routine medical assessment were reviewed retrospectively. The prevalence for each syndrome was compared between two groups. Descriptive statistics and Chi-square test were used to analyze these outcomes.

Results: The mean age and sex were not different between the two groups. Comparing the comprehensive geriatric assessment and routine medical assessment groups, there were, respectively, a prevalence of 30% vs. 1% for falls, 16% vs. 19% for dementia, 24% vs. 9% for urinary incontinence, 50% vs. 17% for functional dependency, and 22% vs. 14% for depression. Each syndrome was more prevalent with increasing age and in females. Falls (RR 2.79; 95% CI, 2.07-3.75), functional dependency (RR 2.24; 95% CI, 1.51-3.33) and urinary incontinence (RR 1.79; 95% CI, 1.18-2.70) had significantly higher prevalence in the comprehensive geriatric assessment group compared with the routine medical assessment group.

Conclusions: Geriatric syndromes were highly prevalent in the elderly outpatient population. Under-recognition of these syndromes with routine medical assessments is common. Therefore, routine screening of these conditions by the comprehensive geriatric assessment is recommended.

Background: Calcium phosphate cements (CPC) is a promising materials for bone defect repair. Nanosized apatite or calcium orthophosphate has a better bioactivity than coarser crystals. Chitosan is produced commercially from chitin that is the structural element in the exoskeleton of crustaceans such as crabs and shrimp. The mixing of nanosized apatite and chitosan may provide the consistency cement, improving mechanical properties of the set bone cement.

Objective: Develop nanosized apatite powder with chitosan for bone composite cement.

Materials and method: Nanosized apatite was synthesized by chemical method at low temperature and used as the single-component for bone cement. The nanosized apatite powder was characterized using X-ray diffraction method, Fourier transform infrared spectroscopy, and transmission electron microscopy. CPCs were developed based on chitosan/nanosized apatite and calcium sulfate hemihydrate. The compressive strength of the set cement was measured after one to four weeks. The phase composition and the morphology of the set cements were investigated.

Results: Calcium sulfate hemihydrate was effective in increasing the compressive strength after setting in a simulated body fluid for seven days. The compressive strength of chitosan/nanosized apatite composite was about 18 MPa after soaking.

Conclusion: The workability and setting time of this composite were suitable to handling for bone cement. These composite cements had a significant clinical advantage for substitution of the regenerated bone.

Background: Rocuronium is an alternative to succinylcholine for rapid tracheal intubation after major thermal injury and other forms of critical illness that cause denervation changes in skeletal muscle. Rocuronium may decrease the potencies of non-depolarizing muscle relaxants.

Objectives: Examine whether potency of rocuronium changed during the first month after denervation, and investigate the effects of skeletal muscle denervation on potency of rocuronium.

Methods: The denervation mouse model was developed to create denervated individual cells from the flexor digitorum brevis of the hindfoot. The skeletal muscle cells were examined at day 0 in the innervated control and days 1, 4, 7, 14, 21, and 28 in the denervation group. Nicotinic acetylcholine receptors in the cells were activated with 30 M acetylcholine, alone or in combination with various concentrations of rocuronium. Currents were recorded with a whole-cell patch-clamp technique.

Results: Rocuronium reversibly inhibited acetylcholine-activated currents in a dose-dependent fashion at different times after denervation. The inhibition concentration for the half-maximal responses of rocuronium increased 1.2- (p >0.05), 1.8-, 2.8-, 2.3-, 2.1-, and 1.9-fold (p <0.01) at day 1, 4, 7, 14, 21, and 28 after denervation, respectively, compared to that at day 0 after denervation.

Conclusion: Rocuronium dose required to achieve satisfactory clinical effects changed at different durations after skeletal muscle denervation.

Background: Scaffolds for bone tissue engineering must meet functional requirements, porosity, biocompatibility, and biodegradability. Different polymeric scaffolds have been designed to satisfy these properties. Composite materials could improve mechanical properties compared with polymers, and structural integrity and flexibility compared with brittle ceramics.

Objective: Fabricate poly (lactic-co-glycolic acid) (PLGA) /hydroxyapatite (HA) porous scaffolds by freezeextraction method, and evaluate the possibility for optimizing their biocompatibility by changing their HA content.

Methods: Porous PLGA/HA composites structure were prepared by freezing a polymer solution, and then the solvent was extracted by a non-solvent and subsequently air-dried. The scaffolds were coated with triblock copolymer and sterilized by ultraviolet light. Human mesenchymal stem cells were cultured on the prepared scaffolds and were studied after three days by 4, 6-diamidino-2-phenylindole (DAPI) fluorescence microscopy.

Results: Microstructural studies with SEM showed the formation of about 50 micrometer size porous structure and interconnected porosity so that cells were adhered well into the structure of the coated samples. DAPI fluorescence microscopy showed more cell adhesion to the coated scaffolds and cell diffusion into the pores are visible. Direct assay of cell proliferation performed with MTT test showed cell growing on the scaffold similar to or more than on control samples.

Conclusion: The triblock-coated PLGA/HA porous scaffolds may provide cell adhesion and proliferation, demonstrating their potential application in bone engineering.

Background: Sleep-disordered breathing or obstructive sleep apnea (OSA) has an important effect on the quality of life. Very few data of OSA are available for Thai persons.

Objective: Investigate the prevalence of high risk to OSA and the relationship between OSA and risk factors in Thai medical students.

Materials and methods: Three hundred seven subjects were recruited from all of the medical students (fourth year to sixth year) the Faculty of Medicine, Srinakharinwirot University, Thailand for this cross-sectional study. Data was collected between June and September 2010. The Berlin questionnaire was used to determine risk for OSA. Logistic regression analysis was performed with p-value less than 0.05 for statistical significance.

Results: The prevalence of high risk to OSA was 6.8%. Total mean of sleep duration, bedtime, and wake-time was 6.59 hours. Bedtime of male students was significantly later than female students. The medical students with body mass index (BMI) >23 kilogram/meter² and with underlying diseases were at high-risk for OSA.

Conclusion: Prevalence of high-risk to OSA of Thai medical students was 6.8%. The medical students with BMI >23 kilogram/meter² and with underlying diseases were at high risk for OSA but gender, age, academic year, and academic achievement did not relate to OSA.

Background: Visceral adipose tissue-derived serine protease inhibitor (vaspin) is a novel adipocytokine. Several studies have indicated that vaspin may exert an important role in the development of metabolic disorders.

Objective: Evaluate serum vaspin and its relation to clinical parameters in newly and previously diagnosed Chinese type 2 diabetes mellitus (T2DM) females as a case-control study.

Materials and methods: One hundred twenty female participants (newly and previously diagnosed T2DM patients) were recruited from an affiliated hospital of Harbin Medical University. Sixty healthy female volunteers from various communities were included as controls. Anthropometric parameters, serum fasting blood glucose, fasting insulin, lipid profile, HbA1c, and vaspin were measured in each participant.

Results: Serum vaspin levels were significantly lower in previously diagnosed T2DM patients (0.51±0.29 ng/mL) than in newly diagnosed T2DM patients (0.62±0.28 ng/mL) and healthy controls (0.69±0.31 ng/mL). However, there was no difference in serum vaspin between newly diagnosed T2DM patients and healthy controls. In multiple linear regression analysis, serum vaspin was significantly and positively associated with HbA1c in both newly and previously diagnosed T2DM patients, negatively associated with homeostasis model assessment of insulin resistance in previously diagnosed patients, and positively correlated with age and body mass index in healthy controls.

Conclusion: Serum vaspin was significantly lower in previously diagnosed T2DM patients than in newly diagnosed T2DM patients and healthy controls. Serum vaspin might be a predictor of poor glucose control and insulin resistance in T2DM.

Background: Eye injuries, especially open globe injuries, cause visual morbidities and socioeconomic burden. It is urgent have good database and stakeholder involvement for open globe injuries.

Objectives: Investigate the epidemiology and predictive factors of visual outcome in open globe injuries in an industrial area in Thailand.

Methods: Consecutive cases of in-patient open globe injuries in Mettapracharak Eye Centre between February 2009 and January 2010 were examined. Patients were interviewed at first visit and followed-up for six months. The Birmingham Eye Trauma Terminology was used to classify types of injuries. Demographic data, cost of treatment, length of stay, and predictive factors (initial visual acuity, presence of relative afferent pupillary defect, hyphema, vitreous hemorrhage, intraocular foreign bodies, retinal detachment, time-duration to surgery, and wound length) were assessed.

Results: Fifty-two out of 60 eyes were included. Most (82.7%) of patients were men and average age was 34.1 years (range: 8-68 years). About half (51.9%) graduated from primary school and 65.3% were labourers. Most patients had not used protective devices. The endophthalmitis rate was 13.5%, and panophthalmitis rate was 5.8%. The enucleation rate was 9.6%. The median length of stay was nine days. Poor initial visual acuity and intraocular foreign bodies were significant predictive factors of poor visual outcome (p <0.05).

Conclusion: Open globe injuries caused visual morbidity especially in young adult male, laborers with low education. Initial visual acuity and intraocular foreign bodies were significant predictive factors of poor visual outcome.

Background: Patient’s conebeam computer tomography (CBCT) images have suggested a possibility for adaptive radiotherapy although the dose delivery is of structural complexity. It is of practical importance to verify and test the intensity-modulated radiation (IMRT) planning system for radiation therapy.

Objective: Verify accuracy of dose calculations based on CBCT imaging.

Materials and methods: Electron density calibration curve was generated for planning CT and CBCT data set using two CT phantoms (Gammex RMI® and Catphan® 600). Anthropomorphic head and neck phantom images were acquired from planning CT and CBCT. The routine IMRT technique was generated on the planning CT, which was applied to the CBCT. Dose distributions were computed. All LiF TLD-100 dosimeters were calibrated with gamma-ray. Forty-eight TLD measuring points were chosen in five different slices of the phantom. Measurements were repeated four times, and the average dose was compared to the reading doses on both CT and CBCT plans. Dose volume histograms (DVH) of various structures were generated, and dose statistics were analyzed.

Results: Hounsfield unit obtained from Catphan phantom was similar between planning CT and CBCT. IMRT dose calculations based on the planning CT and CBCT agreed well with reading doses at 48 points. Statistical point doses by DVH calculation on CBCT were about 3% lower than those by the conventional CT. Dose ratios calculated over measured ones ranged from 0.82 to 1.09.

Conclusion: Point doses and DVH calculations based on the planning CT and on-board CBCT were in acceptable agreement. CT phantom specifically designed for CBCT is recommended to improve accuracy of IMRT dose calculation on CBCT images.

Background: Cardiovascular magnetic resonance imaging (CMR) has recently been accepted as a preferential method for evaluation left ventricular ejection fraction (LVEF). The LVEF analysis by CMR is usually performed by trained technologists in many institutions of Thailand.

Objective: Assess the reproducibility of LVEF measured by a cardiovascular radiologist and a trained technologist using CMR in patients with post-myocardial infarction (MI).

Methods: Twenty-one MI patients (18 men and 3 women) were recruited, where nine patients underwent CMR and left ventriculography to follow-up LVEF two times in six months. Both CMR and left ventriculography were examined within two weeks. LVEF from CMR were measured by a cardiovascular radiologist and a trained technologist and the correlation between the left ventriculography and CMR was determined.

Results: In 30 CMR studies, interobserver reliability (intraclass correlation coefficient ICC=0.94) and intraobserver reliability (ICC=0.96) was excellent. LVEF measured by left ventriculography was higher compared with that by CMR, and their correlation was moderate (ICC=0.56).

Conclusion: The LVEF measurement by a cardiovascular radiologist and a trained technologist using CMR was very reproducible, but the correlation between CMR and left ventriculography was moderate.

Background: When a periprosthetic infection is diagnosed, the surgical treatment is usually performed as soon as possible to avoid further bone damage or life threatening complications. There is no report on the radiographic change in patients with untreated infected total hip arthroplasty (THA) for several years.

Objective: Report radiographic change in patients with untreated infected THA.

Method: Two patients presented with chronic septic loosening of cemented acetabular fixation after total hip replacement at King Chulalongkorn Memorial Hospital. Both patients had mild hip pain and had been lost for follow-up until the bone destruction became very severe. Serial radiographs after the surgeries were evaluated. The Paprosky’s acetabular bone loss classification was used to classify the radiographic findings.

Results: Based on the Paprosky’s classification for acetabular bone loss, there were two similar atypical radiographic findings found in both patients. These included pelvic discontinuity from extensive medial acetabular bone loss beyond the Kohler’s line, and minimal superior and inferior acetabular bone loss.

Conclusion: These atypical radiographic findings were rarely observed in septic acetabular loosening patients, as infection usually causes patients to present earlier. Following the septic acetabular loosening of THA, surgical procedure should be performed before massive bone damage was demonstrated.

Background: Familial adenomatous polyposis (FAP) is an inherited colorectal cancer predisposing syndrome that has an autosomal dominant mode of inheritance with complete penetrance. Although the disease-causing gene of FAP, the adenomatous polyposis coli (APC) gene, is well understood, genetic testing for FAP remains uncommon in Thailand, possibly because of its high cost.

Objective: Present a family in southern Thailand that had benefited from this test.

Subject and methods: The proband was a 31-year-old man who had rectal cancer with profuse adenomatous polyposis of his colon.

Results: APC mutation screening revealed a novel mutation at codon 1249 (TGC1249TAA) that could predict a premature stop codon. On screening of three siblings in the same generation who were alive and 11 members of the descendant generation, four cases were positive for the mutation. The positive members were confirmed to have a type of diffuse colonic polyposis by endoscopy, and a prophylactic colectomy was performed without complications for every affected individual.

Conclusion: A genetic test is cost-effective. It should be considered for FAP, especially when the number of at-risk family members is high.