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  1. Fulltext Prevalence of obesity and associated factors among secondary school students in Slemani City Kurdistan Region, Iraq
    Muhammad Saeed Qadir, Rampal, Lekhraj, Sherina Mohd Sidik, Salmiah Md Said, Zhian Salah Ramzi
    Malaysian Journal of Medicine and Health Sciences, 2014;10(2):27-38.
    MyJurnal
    Obesity is a well-established risk factor for cardiovascular disease. The objective of
    the study was to determine the prevalence of obesity and factors associated among secondary school students aged between 13 to 17 years at Slemani City Centre, Iraq. Methodology: A cross sectional study design was used. The calculated sample size was 1656. Probability proportional to size sampling technique was used to select the sample. A validated pretested questionnaire was used to collect the data. Weight and height were also taken. Data were analyzed using SPSS version 21. Chi-square test was used to determine an association between two categorical variables. Independent t-test was used to compare two means. Multiple logistic regression was used to determine the predictors for obesity. Results: The response rate was 92.54% and the overall mean age of the 1588 respondents was 15.42 (95% CI = 15.35, 15.49) years. The prevalence of overweight and obesity was 20.6% and 11.3% respectively. Variables significantly associated with overweight and obesity (age, monthly family income, education level of parents, body part satisfaction and body size perception) were entered into the logistic regression model. Multiple logistic regression analysis showed that the predictors for overweight and obesity were age, monthly family income, body part dissatisfaction and body size perception. Conclusion: The prevalence of overweight and obesity is high (20.6% and 11.3% respectively). The predictors of obesity among secondary school students aged between 13 to 17 years old at Slemani City Centre Kurdistan Region, Iraq were age, family income and body image dissatisfaction.
    Matched MeSH terms: Sample Size
  2. Rate of tree carbon accumulation increases continuously with tree size
    Stephenson NL, Das AJ, Condit R, Russo SE, Baker PJ, Beckman NG, et al.
    Nature, 2014 Mar 6;507(7490):90-3.
    PMID: 24429523 DOI: 10.1038/nature12914
    Forests are major components of the global carbon cycle, providing substantial feedback to atmospheric greenhouse gas concentrations. Our ability to understand and predict changes in the forest carbon cycle--particularly net primary productivity and carbon storage--increasingly relies on models that represent biological processes across several scales of biological organization, from tree leaves to forest stands. Yet, despite advances in our understanding of productivity at the scales of leaves and stands, no consensus exists about the nature of productivity at the scale of the individual tree, in part because we lack a broad empirical assessment of whether rates of absolute tree mass growth (and thus carbon accumulation) decrease, remain constant, or increase as trees increase in size and age. Here we present a global analysis of 403 tropical and temperate tree species, showing that for most species mass growth rate increases continuously with tree size. Thus, large, old trees do not act simply as senescent carbon reservoirs but actively fix large amounts of carbon compared to smaller trees; at the extreme, a single big tree can add the same amount of carbon to the forest within a year as is contained in an entire mid-sized tree. The apparent paradoxes of individual tree growth increasing with tree size despite declining leaf-level and stand-level productivity can be explained, respectively, by increases in a tree's total leaf area that outpace declines in productivity per unit of leaf area and, among other factors, age-related reductions in population density. Our results resolve conflicting assumptions about the nature of tree growth, inform efforts to undertand and model forest carbon dynamics, and have additional implications for theories of resource allocation and plant senescence.
    Matched MeSH terms: Sample Size
  3. Fulltext Psychometric properties of the QOLLTI-F questionnaire to assess quality of life in caregivers of cancer patients
    Rafi Mahmoud Alnjadat, Aasim Adnan, Zalina Ismail
    Education in Medicine Journal, 2014;6(2):41-47.
    MyJurnal
    Aim: The objective of the present study was to assess the validity and reliability of Malay version of the QOLLTI-F questionnaire.
    Methods: A total of 80 Malay caregivers of cancer patients in an outpatient oncology clinic were enrolled in this study. A translated QOLLTI-F questionnaire of 16 items was used in order to assess their quality of life. Demographic characteristics were recorded. Both face and content validity of the translated version were carried out by professionals and the construct validity of the questionnaire was assessed by exploratory factor analysis.
    Results: Exploratory factor analysis led to the extraction of seven factors and this was consistent with the English version. Cronbach Alpha coefficient showed good consistency of the questions within the sub-scales (Cronbach's alpha > 0.7).
    Conclusion: This study was confined to a Malay population, and the analyses were potentially limited by a small sample size .Nevertheless, the translated questionnaire demonstrated valid and reliable psychometric properties when administered to Malay caregivers. Future studies are needed to see if this instrument can fit other samples in different settings and populations.
    Study site: Oncology clinic, Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia
    Matched MeSH terms: Sample Size
  4. Fulltext Stress and coping strategies among Management and Science University students: A qualitative study
    Redhwan, A.A.N., Sami, A.R., Karim, A.J., Chan, R., Zaleha, M.I.
    International Medical Journal Malaysia, 2009;8(2):11-16.
    MyJurnal
    Introduction: This study aimed to explore the associated factors related to causes of stress and coping strategies among university students. Materials and Methods: As a focus group discussion, it was universal sampling, conducted among 39 of Medical Science and Biomedicine students on their second semester from Management and Science University (MSU), Shah Alam, Malaysia. Three issues were discussed: firstly, how they define the stress; secondly, what the most important causes of stress in their life are; and thirdly, how they cope with stress. Verbal consent was obtained from all participants. Due to the small sample size, the data was analyzed manually. Results: Total of participants were 39 students, their age ranged from 21 to 26 years. Seventeen (43.6%) of the students were 21 years old and the majority were female 31 (79.5%). The
    most important causes of stress reported by the students were financial, lack of sleep, and family problems. In terms of coping with stress, the students were able to describe a variety of strategies to cope with their stressful situations. These included counseling services, doing meditation, sharing of problems, getting adequate sleep, and going out with friends. Conclusion: Most of the students defined stress as “a mental condition”. Lack of sleep, financial, and family problems were the most causes of stress among students. The students were able to identify some strategies to cope with stress.
    Matched MeSH terms: Sample Size
  5. Fulltext Pyrosequencing-based quantitative evaluation of P16 methylation in diffuse large b-cell lymphoma
    Mohd. Ridah L.J., Ismail A., A. Talib N., Muhammad N., Hussain F.A., Zainuddin N.
    Journal of Biomedical and Clinical Sciences, 2016;1(1):12-17.
    MyJurnal
    Introduction: Methylation of promoter region of p16 leading to gene silencing has been implicated ina wide range of malignancies including lymphomas. In diffuse large B cell lymphoma (DLBCL) particularly, a varying percentage of epigenetic inactivation of p16 promoter region was observed ranging from 16 -54%. However, quantitative analysis of p16 promoter methylation in DLBCL has not been extensively studied in Malaysia. Objective: This study aims to quantitatively analyse p16 methylation in DLBCL samples using pyrosequencing technique. Methods: Genomic DNA was extracted from 16 formalin-fixed paraffin-embedded lymphoma tissue blocks from patients diagnosed with DLBCL. Samples were retrieved from Hospital Tengku Ampuan Afzan, Pahang and Hospital Universiti Sains Malaysia, Kelantan. Primers were designed to amplify bisulfite-treated DNA targeting p16 promoter region. Methylation status of 7 CpG sites was determined by pyrosequencing. Results: All the 16 samples studied showed promoter methylation of p16. The range of mean methylation percentage was between 18 to 81%. Conclusion: The present study has successfully measured the level of methylation of p16 in all 7 CpG sites despite the limitation in sample size. Since p16 methylation is a common event in our series of DLBCL cases, it is worth including a larger sample size in future studies to increase the chance of finding a significant correlation with clinical parameters.
    Matched MeSH terms: Sample Size
  6. Fulltext A genetic programming approach to oral cancer prognosis
    Tan MS, Tan JW, Chang SW, Yap HJ, Abdul Kareem S, Zain RB
    PeerJ, 2016;4:e2482.
    PMID: 27688975 DOI: 10.7717/peerj.2482
    The potential of genetic programming (GP) on various fields has been attained in recent years. In bio-medical field, many researches in GP are focused on the recognition of cancerous cells and also on gene expression profiling data. In this research, the aim is to study the performance of GP on the survival prediction of a small sample size of oral cancer prognosis dataset, which is the first study in the field of oral cancer prognosis.
    Matched MeSH terms: Sample Size
  7. Fulltext Sample Size Calculation in Animal Studies Using Resource Equation Approach
    Arifin WN, Zahiruddin WM
    Malays J Med Sci, 2017 Oct;24(5):101-105.
    PMID: 29386977 MyJurnal DOI: 10.21315/mjms2017.24.5.11
    Animal research plays an important role in the pre-clinical phase of clinical trials. In animal studies, the power analysis approach to sample size calculation is recommended. Whenever it is not possible to assume the standard deviation and the effect size, an alternative to the power analysis approach is the 'resource equation' approach, which sets the acceptable range of the error degrees of freedom (DF) in an analysis of variance (ANOVA). The aim of this article is to guide researchers in calculating the minimum and maximum numbers of animals required in animal research by reformulating the error DF formulas.
    Matched MeSH terms: Sample Size
  8. Fulltext Sample size and non-normality effects on goodness of fit measures in structural equation models
    Ainur, A.K., Sayang, M.D., Jannoo, Z., Yap, B.W.
    Pertanika Journal of Science & Technology, 2017;25(2):575-586.
    MyJurnal
    A Structural Equation Model (SEM) is often used to test whether a hypothesised theoretical model agrees with data by examining the model fit. This study investigates the effect of sample size and distribution of data (normal and non-normal) on goodness of fit measures in structural equation model. Simulation results confirm that the GoF measures are affected by sample size, whereas they are quite robust when data are not normal. Absolute measures (GFI, AGFI, RMSEA) are more affected by sample size while incremental fit measures such as TLI and CFI are less affected by sample size and non-normality.
    Matched MeSH terms: Sample Size
  9. Fulltext Gamma-tocotrienol Alters Protein Expression of HepG2 Cell Line
    Farahani, A.S.R., Zakiah, J., Abdul Rahman, M., Karsani, S.A., Wan, Ngah Wz
    Medicine & Health, 2008;3(2):256-262.
    MyJurnal
    Gamma-tocotrienol (GTT) has been shown to exhibit significant antitumor activity in a variety of tumor cells. Previous findings have demonstrated that GTT had antiprolifera-tive effects on a liver cancer cell line (HepG2) with an IC50  value of 170μM. In this study, two dimensional gel electrophoresis (2DE) was used to determine changes in protein expression in HepG2 cell line following treatment with GTT. The ultimate aim is to identify the possible molecular mechanisms involved in GTT antitumor activity. This study is focused on obtaining a 2DE protein profile for HepG2 cell line with and without
    GTT treatment. In the preliminary analysis  of the resulting 2DE profiles, 18 protein spots were found to be differentially expressed in cells treated with GTT. This observa-tion is confirmed by extending the analysis  to a larger sample size. By studying the effects of GTT treatment on differential protein expression in HepG2 cells the underly-ing mechanisms involved in the antitumor activity of GTT may be elucidated.
    Matched MeSH terms: Sample Size
  10. Fulltext Preliminary study of PAX9 single nucleotide polymorphism (rs8004560) in patients with Class II skeletal base malocclusion contributed by mandibular retrognatism
    Muhammadazril Mohd Saad, Nur Amin Abd Rahman, Khairani Idah Mokhtar, Noraini Abu Bakar, Azrul Fazwan Kharuddin, Wan Rohani Wan Taib
    Archives of Orofacial Sciences, 2018;13(2):1-7.
    MyJurnal
    Polymorphism in PAX9 (rs8004560), a gene responsible for craniofacial and tooth development, is often associated with Class II/Div2 malocclusion. This study aimed to detect the presence of PAX9 SNP (rs8004560) and to determine its genotype and allele distribution in Class II skeletal base malocclusion, contributed by retrognathic mandible, in the local Malaysian population. The association of PAX9 SNP (rs8004560) with Class II skeletal base malocclusion was also determined. A case control study was performed on 30 samples; 15 from Class II skeletal base malocclusion, and 15 from Class I skeletal base subject as control. Cephalometric measurements were performed prior to saliva samples collection. Genomic DNA was extracted from unstimulated saliva of all subjects, and the DNA was amplified using specific primers for marker rs8004560, followed by genotyping by sequencing. SHEsis online software was used to analyse Hardy-Weinberg Equilibrium (HWE) for cases and controls. Allelic and genotypic frequencies were compared between cases and controls. Significant difference in allele frequency was observed within the group whereby G allele was over-represented in the analysed population (p0.05). Although no genetic association between PAX9 SNP (rs8004560) with Class II skeletal base malocclusion was observed, significant difference in allele frequency observed might provide some indication in the involvement of PAX9 polymorphism in Class II skeletal base malocclusion contributed by retrognathic mandible. Further research utilising larger sample size will be required in order to determine the role of PAX9 gene in the aetiology of Class II skeletal base malocclusion observed in the local Malaysian population.
    Matched MeSH terms: Sample Size
  11. Fulltext Introduction to sample size calculation
    Wan Nor Arifin
    Education in Medicine Journal, 2013;5(2):89-96.
    MyJurnal
    One of the most common reasons why researchers seek help from statistician is sample size calculation. However despite the common believe that it only involves formula and calculation, researchers often ignore other aspects of research design that leads to proper sample size calculation. In this article, the author outlines basic steps toward sample size calculation. The author also introduces the logic behind sample size calculation for single mean and single proportion in simplified and less intimidating forms to those not statistically inclined.
    Matched MeSH terms: Sample Size
  12. Fulltext Does picky eating behavior exist in University students?
    Nur Fadzlina Zulkefli, Muhammad Muzaffar Ali Khan Khattak, Wan Azdie Mohd Abu Bakar
    International Journal of Allied Health Sciences, 2018;2(1):140-154.
    MyJurnal
    The aim of this study was to assess picky eating behavior existence among university students. This was an observational cross sectional study design. The sample size was calculated by using single proportion formula based on the adult prevalence of picky eating of 28.7 % which gives a sample of ~ 324 students. However, 407 students online registered to participate out which 403 students responded. A set of questionnaire was posted online. The questionnaire contained three sections which are demographic information, determinants of picky eating behavior and normal eating behaviors. Furthermore, the students were categorized as non-picky eating behavior, moderate picky eating behavior, and extreme picky eating behavior. The statistical analysis
    carried out was mainly descriptive in order to determine the extent of picky eating behavior among the university students. Student t-test was used to find the differences between picky and non-picky eaters in terms of eating behaviors. Among the students possessing non picky eating behavior, moderate picky eating behavior and extreme picky eating behavior were 168 (41.69%), were 130(32.26%), 105(26.05%) respectively. On overall basis 235(58.31 %) of the students were having picky eating behavior. The present study revealed that picky eating behavior exists among the university students which need to be addressed.
    Matched MeSH terms: Sample Size
  13. Vector competence of Malaysian Aedes aegypti to Zika virus and impact of sequential arbovirus infections
    Ong NH, Chua CL, Liew JWK, Wan Sulaiman WY, Chan YF, Sam IC, et al.
    Acta Trop, 2020 Aug;208:105472.
    PMID: 32389451 DOI: 10.1016/j.actatropica.2020.105472
    Zika virus (ZIKV) is a mosquito-borne flavivirus with global impact since 2015. Although ZIKV was first isolated from Aedes aegypti in Malaysia in 1965, not much is known about the competency of Malaysian Ae. aegypti to ZIKV. To date only 9 cases of ZIKV have been reported in Malaysia despite the abundance of mosquito vectors. This study aimed to determine the susceptibility of Ae. aegypti to ZIKV, and the impact of sequential infections in Ae. aegypti mosquitoes with DENV serotype 2 (DENV-2) followed by ZIKV. Field-caught urban Ae. aegypti were orally challenged with a Martinique strain of ZIKV, and midgut, head/thorax and saliva were collected at 3, 7 and 14 days post-infection (dpi). At 14 dpi, ZIKV-exposed mosquitoes had infection and dissemination rates of 59% (n=10/17) and 90% (n=9/10), respectively. Average titres of 3.9 and 4.4 log pfu infectious ZIKV were recovered in midgut and head/thorax, respectively. In sequential infection, prior exposure of Ae. aegypti to DENV did not affect the subsequent ZIKV infection in head/thorax albeit with a low sample size. In conclusion, Malaysian urban Ae. aegypti is susceptible to the contemporary Asian lineage of ZIKV. The established and continuous DENV circulation in Ae. aegypti did not suppress ZIKV emergence in Malaysia. Other factors contributing to low level of ZIKV circulation in Malaysia remain to be explored.
    Matched MeSH terms: Sample Size
  14. Fulltext An audit of paediatric dental patient assessment and recall in faculty of dentistry UiTM Sungai Buloh
    Aimi Shafiqah Shukri, Muhammad Syazwan Hassan, Venkiteswaran, Annapurny
    Compendium of Oral Science, 2019;6(1):26-34.
    MyJurnal
    Objective: To assess if the recall appointments and the use of radiographs for paediatric dental patients at Faculty of Dentistry, UiTM comply with current guidelines. Materials and Method: A retrospective study was conducted using patients’ dental records that were registered at the Faculty of Dentistry UiTM. The sample consisted of 350 randomly chosen treatment records of paediatric patients aged between birth and 16 years of age at the time of data collection which was in the year 2016. Data collection included demographic details, whom the cases were treated by, caries risk assessment, radiographs taken and time taken for the patient’s review appointments. Results: An initial sample size of 350 records were assessed. The mean age of patients seen when they were first seen is 6.3 years old. Caries Risk Assessment was not reported in majority of the cases (58%,). Baseline radiographs were taken in 44.6% of the cases. For the assessment of recall attendance, only samples with data on CRA was analysed (n=145). The review appointments at 3 months interval was 70% whereas at 6 months was 6.2% and one year recall was 6.7%. A chi-square test showed significant difference (p=0.013) between the category of operators for the 1-year review whereby review was higher among students and specialists as compared to dental officers. Conclusion: This study shows poor adherence to the recommended recall protocol as suggested by NICE and AAPD guidelines. Further studies need to be done to assess the patients’ and clinicians awareness regarding the recall protocol and determine the problems causing poor recall attendance.
    Matched MeSH terms: Sample Size
  15. Fulltext Knowledge and attitude on infant oral health among graduating medical students in kulasekaram
    Chellaih P, Sivadas G, Vaishnavi Vedam VK
    J Educ Health Promot, 2020;9:207.
    PMID: 33062740 DOI: 10.4103/jehp.jehp_194_20
    AIM: This study was intended to evaluate the knowledge and attitudes regarding infant's oral health care among graduating medical students from Kulasekaram, Tamil Nadu.

    MATERIALS AND METHODS: A cross-sectional survey research design was employed in this study. Self-administered questionnaire of the validated "Graduating medical students' Knowledge and Attitudes Survey Regarding Infant's oral health care" were utilized to ascertain the baseline levels of knowledge and attitudes of graduating medical students' in Kulasekaram hospital. In this regard, a preliminary study with a convenience sample of 100 medical students was conducted so as to assess the knowledge of infant oral health care among graduating medical students in Kulasekaram. This study, while limited in sample size, benefits the general practitioners as target readers to assess the abnormalities in children at early stages of life.

    RESULTS: The results of the study revealed that the mean percentage score overall was 65.7%. Only 3.2% of participants obtained a passing score of 80% or greater. Widespread knowledge deficits and poor attitudes among graduating medical students were noted in this study, particularly in the domain of pharmacological management of pain. Positive correlations were observed between the respondents' score and level of education. Further analysis revealed respondents had an inaccurate self-evaluation of their pain management knowledge.

    CONCLUSION: The results of this study reveal that there is dearth of knowledge and attitudes of graduating medical students' regarding infant oral health care. Educational and quality improvement initiatives in oral health care of infants could enhance medical student's knowledge baseline in the area of oral health care and possibly improve practices.

    Matched MeSH terms: Sample Size
  16. Fulltext Overweight and obesity among employees at a private university in Malaysia: a cross-sectional study towards a healthy workplace
    Jo Ann Andoy-Galvan, Nimesha Tillekeratne, Tilanka Tillekeratne
    Malaysian Journal of Medicine and Health Sciences, 2019;15(102):40-40.
    MyJurnal
    Introduction: Obesity is a growing public health concern. Poor diet and lifestyle choices are the main contributors to its development. Lifestyle modifications should be aggressively promoted in the community. Recent studies found that worksite obesity prevention and control programs are effective in increasing physical activity and weight reduction among employees. In Malaysia, there is insufficient data on prevalence studies of workplaces. This study investigated the proportion of overweight and obesity among workers in a private university and hope to serve as a baseline for future healthy workplace programs. Methods: This cross-sectional study investigated overweight and obesity and examined its association with occupational stress, sleeping quality, dietary behaviour and physical inactivity among employees in an academic institution. Weight and height were measured, and BMI was calculated and coded as underweight, normal, overweight and obese according to the cut-off points for the Asian population. Results: Out of ninety-five employees, 55 participated in the survey. Among the 55 employees, 4 (7.3%) were underweight, 10 (18.2%) were normal, 25 (45.5%) were overweight, and 16 (29.1%) were obese. The obese and overweight proportion was similar to the national prevalence. Poor sleep quality and high Job stress scores were reported by 40% of the employees, while physical inactivity of more than 6 hours a day was reported by 50%, and the majority (90%) do not consume enough fibre. Among the risk factors investigated, none was associated with obesity. Conclusion: The proportion of overweight and obesity in this community was like the general population. While not significant in this study, the association between obesity and the four risk factors should be further investigated using a larger sample size. Based on the results, community-based health promotion intervention is suggested to reduce obesity among the employees.
    Matched MeSH terms: Sample Size
  17. A study on the S2 -EWMA chart for monitoring the process variance based on the MRL Performance
    Teh Sin Yin, Ong Ker Hsin, Soh Keng Lin, Khoo Michael Boon Chong, Teoh Wei Li
    Sains Malaysiana, 2015;44:1067-1075.
    The existing optimal design of the fixed sampling interval S2-EWMA control chart to monitor the sample variance of a process is based on the average run length (ARL) criterion. Since the shape of the run length distribution changes with the magnitude of the shift in the variance, the median run length (MRL) gives a more meaningful explanation about the in-control and out-of-control performances of a control chart. This paper proposes the optimal design of the S2-EWMA chart, based on the MRL. The Markov chain technique is employed to compute the MRLs. The performances of the S2-EWMA chart, double sampling (DS) S2 chart and S chart are evaluated and compared. The MRL results indicated that the S2-EWMA chart gives better performance for detecting small and moderate variance shifts, while maintaining almost the same sensitivity as the DS S2 and S charts toward large variance shifts, especially when the sample size increases.
    Matched MeSH terms: Sample Size
  18. Fulltext Optimal designs of the median run length based double sampling X chart for minimizing the average sample size
    Teoh WL, Khoo MB, Teh SY
    PLoS One, 2013;8(7):e68580.
    PMID: 23935873 DOI: 10.1371/journal.pone.0068580
    Designs of the double sampling (DS) X chart are traditionally based on the average run length (ARL) criterion. However, the shape of the run length distribution changes with the process mean shifts, ranging from highly skewed when the process is in-control to almost symmetric when the mean shift is large. Therefore, we show that the ARL is a complicated performance measure and that the median run length (MRL) is a more meaningful measure to depend on. This is because the MRL provides an intuitive and a fair representation of the central tendency, especially for the rightly skewed run length distribution. Since the DS X chart can effectively reduce the sample size without reducing the statistical efficiency, this paper proposes two optimal designs of the MRL-based DS X chart, for minimizing (i) the in-control average sample size (ASS) and (ii) both the in-control and out-of-control ASSs. Comparisons with the optimal MRL-based EWMA X and Shewhart X charts demonstrate the superiority of the proposed optimal MRL-based DS X chart, as the latter requires a smaller sample size on the average while maintaining the same detection speed as the two former charts. An example involving the added potassium sorbate in a yoghurt manufacturing process is used to illustrate the effectiveness of the proposed MRL-based DS X chart in reducing the sample size needed.
    Matched MeSH terms: Sample Size
  19. Fulltext Visualizing hyperactivation in neurodegeneration based on prefrontal oxygenation: a comparative study of mild alzheimer's disease, mild cognitive impairment, and healthy controls
    Yap KH, Ung WC, Ebenezer EGM, Nordin N, Chin PS, Sugathan S, et al.
    Front Aging Neurosci, 2017;9:287.
    PMID: 28919856 DOI: 10.3389/fnagi.2017.00287
    Background: Cognitive performance is relatively well preserved during early cognitive impairment owing to compensatory mechanisms. Methods: We explored functional near-infrared spectroscopy (fNIRS) alongside a semantic verbal fluency task (SVFT) to investigate any compensation exhibited by the prefrontal cortex (PFC) in Mild Cognitive Impairment (MCI) and mild Alzheimer's disease (AD). In addition, a group of healthy controls (HC) was studied. A total of 61 volunteers (31 HC, 12 patients with MCI and 18 patients with mild AD) took part in the present study. Results: Although not statistically significant, MCI exhibited a greater mean activation of both the right and left PFC, followed by HC and mild AD. Analysis showed that in the left PFC, the time taken for HC to achieve the activation level was shorter than MCI and mild AD (p = 0.0047 and 0.0498, respectively); in the right PFC, mild AD took a longer time to achieve the activation level than HC and MCI (p = 0.0469 and 0.0335, respectively); in the right PFC, HC, and MCI demonstrated a steeper slope compared to mild AD (p = 0.0432 and 0. 0107, respectively). The results were, however, not significant when corrected by the Bonferroni-Holm method. There was also found to be a moderately positive correlation (R = 0.5886) between the oxygenation levels in the left PFC and a clinical measure [Mini-Mental State Examination (MMSE) score] in MCI subjects uniquely. Discussion: The hyperactivation in MCI coupled with a better SVFT performance may suggest neural compensation, although it is not known to what degree hyperactivation manifests as a potential indicator of compensatory mechanisms. However, hypoactivation plus a poorer SVFT performance in mild AD might indicate an inability to compensate due to the degree of structural impairment. Conclusion: Consistent with the scaffolding theory of aging and cognition, the task-elicited hyperactivation in MCI might reflect the presence of compensatory mechanisms and hypoactivation in mild AD could reflect an inability to compensate. Future studies will investigate the fNIRS parameters with a larger sample size, and their validity as prognostic biomarkers of neurodegeneration.
    Matched MeSH terms: Sample Size
  20. High-Throughput RT-qPCR for the Analysis of Circulating MicroRNAs
    Tan GW, Tan LP
    Methods Mol Biol, 2017;1580:7-19.
    PMID: 28439823 DOI: 10.1007/978-1-4939-6866-4_2
    Reverse transcription followed by real-time or quantitative polymerase chain reaction (RT-qPCR) is the gold standard for validation of results from transcriptomic profiling studies such as microarray and RNA sequencing. The current need for most studies, especially biomarker studies, is to evaluate the expression levels or fold changes of many transcripts in a large number of samples. With conventional low to medium throughput qPCR platforms, many qPCR plates would have to be run and a significant amount of RNA input per sample will be required to complete the experiments. This is particularly challenging when the size of study material (small biopsy, laser capture microdissected cells, biofluid, etc.), time, and resources are limited. A sensitive and high-throughput qPCR platform is therefore optimal for the evaluation of many transcripts in a large number of samples because the time needed to complete the entire experiment is shortened and the usage of lab consumables as well as RNA input per sample are low. Here, the methods of high-throughput RT-qPCR for the analysis of circulating microRNAs are described. Two distinctive qPCR chemistries (probe-based and intercalating dye-based) can be applied using the methods described here.
    Matched MeSH terms: Sample Size
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