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author:("laing, Lin")
1.  Alpha Amylase as a Salivary Biomarker of Acute Stress of Venepuncture from Periodic Medical Examinations 
Periodic occupational health examinations often require venepuncture. Acute psychological and physical stressors during such procedure result in sympathetic stimulation and increased salivary protein secretion, including salivary α-amylase (SAA). We studied SAA response to venepuncture during such examination. Fifty-eight healthy males undergoing periodic medical examination reported perceived stress level (PSL) scores (on a five-point scale) and provided passive drool saliva samples at 15-min (T1) and 1-min before (T2); and 1-min (T3) and 15-min after venepuncture (T4). A subset of 33 participants available for repeat examination on a control day when there was no venepuncture provided saliva samples at the corresponding times for comparison. Saliva SAA activity levels were analyzed using a SAA assay kit (Salimetrics LLC, USA). Among 58 participants, mean SAA increased from T1 (89.95 U/L) to T2 (109.5 U/L) and T3 (116.9 U/L). SAA remained elevated 15 min after venepuncture (121.0 U/L). A positive trend in the difference of SAA between T3 and T1 was noted among subjects with increasing mean PSL scores. T3–T1 values were 0.6 (among those with PSL ≤ 1, n = 24), 11.3 (among those with PSL between 1 and 1.5, n = 18), and 78.9 (among those with PSL > 1.5, n = 16). SAA increment over four-time points was significantly higher on the venepuncture compared to the control day (P = 0.021). SAA increases in response to the acute stress of venepuncture during a periodic medical examination, and remains elevated 15 min after the procedure. In comparison, such fluctuations in SAA were not seen on a control day. During venepuncture, increase in SAA from baseline is higher among those who reported greater self-perceived stress during the procedure.
PMCID: PMC4143618  PMID: 25207265
salivary biomarker; alpha amylase; venepuncture; acute stress; periodic medical examination
2.  Validating Age-related Functional Imaging Changes in Verbal Working Memory with Acute Stroke 
Behavioural neurology  2011;24(3):187-199.
Functional imaging studies consistently find that older adults recruit bilateral brain regions in cognitive tasks that are strongly lateralized in younger adults, a characterization known as the Hemispheric Asymmetry Reduction in Older Adults model. While functional imaging displays what brain areas are active during tasks, it cannot demonstrate what brain regions are necessary for task performance. We used behavioral data from acute stroke patients to test the hypothesis that older adults need both hemispheres for a verbal working memory task that is predominantly left-lateralized in younger adults. Right-handed younger (age <51, n = 7) and older adults (age > 50, n = 21) with acute unilateral stroke, as well as younger (n = 6) and older (n = 13) transient ischemic attack (TIA) patients, performed a self-paced verbal item-recognition task Older patients with stroke to either hemisphere had a higher frequency of deficits in the verbal working memory task compared to older TIA patients. Additionally, the deficits in older stroke patients were mainly in retrieval time while the deficits in younger stroke patients were mainly in accuracy. These data suggest that bihemispheric activity is necessary for older adults to successfully perform a verbal working memory task.
PMCID: PMC3177151  PMID: 21876259
working memory; aging; lesion; stroke
3.  Capacity-Speed Relationships in Prefrontal Cortex 
PLoS ONE  2011;6(11):e27504.
Working memory (WM) capacity and WM processing speed are simple cognitive measures that underlie human performance in complex processes such as reasoning and language comprehension. These cognitive measures have shown to be interrelated in behavioral studies, yet the neural mechanism behind this interdependence has not been elucidated. We have carried out two functional MRI studies to separately identify brain regions involved in capacity and speed. Experiment 1, using a block-design WM verbal task, identified increased WM capacity with increased activity in right prefrontal regions, and Experiment 2, using a single-trial WM verbal task, identified increased WM processing speed with increased activity in similar regions. Our results suggest that right prefrontal areas may be a common region interlinking these two cognitive measures. Moreover, an overlap analysis with regions associated with binding or chunking suggest that this strategic memory consolidation process may be the mechanism interlinking WM capacity and WM speed.
PMCID: PMC3223164  PMID: 22132105
4.  Development and validation of a new Prescription Quality Index 
The aims were to develop and validate a new Prescription Quality Index (PQI) for the measurement of prescription quality in chronic diseases.
The PQI were developed and validated based on three separate surveys and one pilot study. Criteria were developed based on literature search, discussions and brainstorming sessions. Validity of the criteria was examined using modified Delphi method. Pre-testing was performed on 30 patients suffering from chronic diseases. The modified version was then subjected to reviews by pharmacists and clinicians in two separate surveys. The rater-based PQI with 22 criteria was then piloted in 120 patients with chronic illnesses. Results were analysed using SPSS version 12.0.1
Exploratory principal components analysis revealed multiple factors contributing to prescription quality. Cronbach's α for the entire 22 criteria was 0.60. The average intra-rater and inter-rater reliability showed good to moderate stability (intraclass correlation coefficient 0.76 and 0.52, respectively). The PQI was significantly and negatively correlated with age (correlation coefficient −0.34, P < 0.001), number of drugs in prescriptions (correlation coefficient −0.51, P < 0.001) and number of chronic diseases/conditions (correlation coefficient −0.35, P < 0.001).
The PQI is a promising new instrument for measuring prescription quality. It has been shown that the PQI is a valid, reliable and responsive tool to measure quality of prescription in chronic diseases.
PMCID: PMC2950985  PMID: 20840442
chronic diseases; Medication Appropriateness Index; prescription; Prescription Quality Index
5.  Knowledge, Attitude and Practice of Sawmill Workers Towards Noise-Induced Hearing Loss in Kota Bharu, Kelantan. 
The purpose of this study was to determine the sawmill workers’ knowledge, attitude and practice (KAP) in relation to noise-induced hearing loss (NIHL). A cross-sectional study was conducted involving 83 workers from 3 factories in Kota Bharu, Kelantan. Questionnaires were distributed to obtain the socio-demography, knowledge, attitude and practice level in relation to noise-induced hearing loss (NIHL). The weak areas identified in the knowledge section were treatment aspects (15.5%), signs and symptoms of NIHL (20.2%) and risk factors (31%). As for attitude; the prevention aspects were the lowest (25.3%), followed by risk taking attitude (26.2%), and causes of hearing loss (42.1%). Overall, the practice was not encouraging at all. It is important to have an education program to raise workers’ awareness and to improve their attitude and practices towards noise-induced hearing loss.
PMCID: PMC3341918  PMID: 22589635
sawmill workers; knowledge; attitude; practice; noise-induced hearing loss
6.  Tooth Wear Prevalence and Sample Size Determination : A Pilot Study 
Tooth wear is the non-carious loss of tooth tissue, which results from three processes namely attrition, erosion and abrasion. These can occur in isolation or simultaneously. Very mild tooth wear is a physiological effect of aging. This study aims to estimate the prevalence of tooth wear among 16-year old Malay school children and determine a feasible sample size for further study. Fifty-five subjects were examined clinically, followed by the completion of self-administered questionnaires. Questionnaires consisted of socio-demographic and associated variables for tooth wear obtained from the literature. The Smith and Knight tooth wear index was used to chart tooth wear. Other oral findings were recorded using the WHO criteria. A software programme was used to determine pathological tooth wear. About equal ratio of male to female were involved. It was found that 18.2% of subjects have no tooth wear, 63.6% had very mild tooth wear, 10.9% mild tooth wear, 5.5% moderate tooth wear and 1.8 % severe tooth wear. In conclusion 18.2% of subjects were deemed to have pathological tooth wear (mild, moderate & severe). Exploration with all associated variables gave a sample size ranging from 560 – 1715. The final sample size for further study greatly depends on available time and resources.
PMCID: PMC3341919  PMID: 22589636
pilot study; tooth wear; prevalence and sample size determination
7.  Working conditions, self-perceived stress, anxiety, depression and quality of life: A structural equation modelling approach 
BMC Public Health  2008;8:48.
The relationships between working conditions [job demand, job control and social support]; stress, anxiety, and depression; and perceived quality of life factors [physical health, psychological wellbeing, social relationships and environmental conditions] were assessed using a sample of 698 male automotive assembly workers in Malaysia.
The validated Malay version of the Job Content Questionnaire (JCQ), Depression Anxiety Stress Scales (DASS) and the World Health Organization Quality of Life-Brief (WHOQOL-BREF) were used. A structural equation modelling (SEM) analysis was applied to test the structural relationships of the model using AMOS version 6.0, with the maximum likelihood ratio as the method of estimation.
The results of the SEM supported the hypothesized structural model (χ2 = 22.801, df = 19, p = 0.246). The final model shows that social support (JCQ) was directly related to all 4 factors of the WHOQOL-BREF and inversely related to depression and stress (DASS). Job demand (JCQ) was directly related to stress (DASS) and inversely related to the environmental conditions (WHOQOL-BREF). Job control (JCQ) was directly related to social relationships (WHOQOL-BREF). Stress (DASS) was directly related to anxiety and depression (DASS) and inversely related to physical health, environment conditions and social relationships (WHOQOL-BREF). Anxiety (DASS) was directly related to depression (DASS) and inversely related to physical health (WHOQOL-BREF). Depression (DASS) was inversely related to the psychological wellbeing (WHOQOL-BREF). Finally, stress, anxiety and depression (DASS) mediate the relationships between job demand and social support (JCQ) to the 4 factors of WHOQOL-BREF.
These findings suggest that higher social support increases the self-reported quality of life of these workers. Higher job control increases the social relationships, whilst higher job demand increases the self-perceived stress and decreases the self-perceived quality of life related to environmental factors. The mediating role of depression, anxiety and stress on the relationship between working conditions and perceived quality of life in automotive workers should be taken into account in managing stress amongst these workers.
PMCID: PMC2267182  PMID: 18254966
8.  A Cross-Sectional Study of Soft Tissue Facial Morphometry in Children and Adolescents 
The aim of this study was to determine mean values for selected linear measurements on the face of children and adolescents to demonstrate gender differences in the measurements. Cross-sectional data from 262 school children (158 male, 104 female) aged between 6 and 15 years were taken by measuring certain identified facial landmarks using a sliding caliper. The landmarks were first located by careful inspection and/or palpation of the face and a mark created on the cutaneous surface, with the subject sitting in habitual occlusion in an upright position. A sliding caliper was used to measure the distances between the points. The data was analysed using SPSS version 10.0 to determine mean values, standard deviation and gender differences in the measurements. Upper facial heights, total facial height, inter-canthal distance and eye length measurements were significantly higher in male than in female for 15-year-old group (p<0.0001). The measurement between the highest and the lowest point of attachment of external ear to the head was significantly larger in male than in female for 11 year old age group.
PMCID: PMC3347899  PMID: 22589587
facial growth; soft tissue facial morphometry

Results 1-8 (8)