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Fulltext Reply to The effect of vigorous physical activity and body composition on cortical bone mass in adolescence

Tan VP, Macdonald HM, McKay HA

J. Bone Miner. Res., 2015 Mar;30(3):585-6.
PMID: 25381875 DOI: 10.1002/jbmr.2399
pink1, atp13a2 and uchl1 expressions are affected by inflammation in the brain

Moriya S, Tan VP, Yee AK, Parhar IS

Neurosci Lett, 2019 08 24;708:134330.
PMID: 31201839 DOI: 10.1016/j.neulet.2019.134330

In Parkinson's disease (PD), several genes have been identified as the PD-related genes, however, the regulatory mechanisms of these gene expressions have not been fully identified. In this study, we investigated the effect of inflammation, one of the major risk factors in PD on expressions of the PD-related genes. Lipopolysaccharide (LPS) was intraperitoneally administered to mature male zebrafish and gene expressions in the brains were examined by real-time PCR. In the inflammation-related genes, expressions of tnfb, il1b and il6 were increased at 2 days post administration in the 10 μg group, and tnfb expression was also increased at 4 days post administration in the 1 μg and 10 μg group. In the PD-related genes, pink1 expression was significantly decreased at 4 days, atp13a2 expression was significantly increased at 7 days, and uchl1 expression was significantly decreased at 7 days. This suggests that pink1, atp13a2 and uchl1 expressions are regulated by inflammation, and this regulatory mechanism might be involved in the progress of PD.
Physical activity, but not sedentary time, influences bone strength in late adolescence

Tan VP, Macdonald HM, Gabel L, McKay HA

Arch Osteoporos, 2018 Mar 20;13(1):31.
PMID: 29556801 DOI: 10.1007/s11657-018-0441-9

Physical activity is essential for optimal bone strength accrual, but we know little about interactions between physical activity, sedentary time, and bone outcomes in older adolescents. Physical activity (by accelerometer and self-report) positively predicted bone strength and the distal and midshaft tibia in 15-year-old boys and girls. Lean body mass mediated the relationship between physical activity and bone strength in adolescents.
PURPOSE: To examine the influence of physical activity (PA) and sedentary time on bone strength, structure, and density in older adolescents.
METHODS: We used peripheral quantitative computed tomography to estimate bone strength at the distal tibia (8% site; bone strength index, BSI) and tibial midshaft (50% site; polar strength strain index, SSIp) in adolescent boys (n = 86; 15.3 ± 0.4 years) and girls (n = 106; 15.3 ± 0.4 years). Using accelerometers (GT1M, Actigraph), we measured moderate-to-vigorous PA (MVPAAccel), vigorous PA (VPAAccel), and sedentary time in addition to self-reported MVPA (MVPAPAQ-A) and impact PA (ImpactPAPAQ-A). We examined relations between PA and sedentary time and bone outcomes, adjusting for ethnicity, maturity, tibial length, and total body lean mass.
RESULTS: At the distal tibia, MVPAAccel and VPAAccel positively predicted BSI (explained 6-7% of the variance, p
Fulltext Influence of physical activity on bone strength in children and adolescents: a systematic review and narrative synthesis

Tan VP, Macdonald HM, Kim S, Nettlefold L, Gabel L, Ashe MC, et al.

J. Bone Miner. Res., 2014 Oct;29(10):2161-81.
PMID: 24737388 DOI: 10.1002/jbmr.2254

A preponderance of evidence from systematic reviews supports the effectiveness of weight-bearing exercises on bone mass accrual, especially during the growing years. However, only one systematic review (limited to randomized controlled trials) examined the role of physical activity (PA) on bone strength. Thus, our systematic review extended the scope of the previous review by including all PA intervention and observational studies, including organized sports participation studies, with child or adolescent bone strength as the main outcome. We also sought to discern the skeletal elements (eg, mass, structure, density) that accompanied significant bone strength changes. Our electronic-database, forward, and reference searches yielded 14 intervention and 23 observational studies that met our inclusion criteria. We used the Effective Public Health Practice Project (EPHPP) tool to assess the quality of studies. Due to heterogeneity across studies, we adopted a narrative synthesis for our analysis and found that bone strength adaptations to PA were related to maturity level, sex, and study quality. Three (of five) weight-bearing PA intervention studies with a strong rating reported significantly greater gains in bone strength for the intervention group (3% to 4%) compared with only three significant (of nine) moderate intervention studies. Changes in bone structure (eg, bone cross-sectional area, cortical thickness, alone or in combination) rather than bone mass most often accompanied significant bone strength outcomes. Prepuberty and peripuberty may be the most opportune time for boys and girls to enhance bone strength through PA, although this finding is tempered by the few available studies in more mature groups. Despite the central role that muscle plays in bones' response to loading, few studies discerned the specific contribution of muscle function (or surrogates) to bone strength. Although not the focus of the current review, this seems an important consideration for future studies.
Admission Clinicopathological Factors Associated with Prolonged Hospital Stay Among Hospitalized Patients with Dengue Viral Infections

Willeam Peter SS, Hassan SS, Khei Tan VP, Ngim CF, Azreen Adnan NA, Pong LY, et al.

Vector Borne Zoonotic Dis, 2019 07;19(7):549-552.
PMID: 30668248 DOI: 10.1089/vbz.2018.2379

Background:
There is an escalation of frequency and magnitude of dengue epidemics in Malaysia, with a concomitant increase in patient hospitalization. Prolonged hospitalization (PH) due to dengue virus (DENV) infections causes considerable socioeconomic burden. Early identification of patients needing PH could optimize resource consumption and reduce health care costs. This study aims to identify clinicopathological factors present on admission that are associated with PH among patients with DENV infections.
Methods:
This study was conducted in a tertiary referral hospital in Southern Malaysia. Relevant clinical and laboratory data upon admission were retrieved from medical records of 253 consecutive DENV nonstructural protein 1 (NS1) antigen and PCR-positive hospitalized patients. The DENV serotype present in each patient was determined. Patients were stratified based on duration of hospital stay (<4 vs. ≥4 days). Data were analyzed using IBM® SPSS® 25.0. Multivariate logistic regression was performed to examine the association between PH and admission parameters.
Results:
Of 253 DENV hospitalized patients, 95 (37.5%) had PH (≥4 days). The mean duration of hospital stay was 3.43 ± 2.085 days (median = 3 days, interquartile range = 7 days). Diabetes mellitus (adjusted odds ratio [AOR] = 6.261, 95% confidence interval [CI] = 2.130-18.406, p = 0.001), DENV-2 serotype (AOR = 2.581, 95% CI = 1.179-5.650, p = 0.018), duration of fever ≤4 days (AOR = 2.423, 95% CI = 0.872-6.734, p = 0.09), and a shorter preadmission fever duration (AOR = 0.679, 95% CI = 0.481-0.957, p = 0.027) were independently associated with PH. However, PH was not found to be associated with symptoms on admission, secondary DENV infections or platelet count, hematocrit, or liver enzyme levels on admission.
Conclusions:
Early identification of these factors at presentation may alert clinicians to anticipate and recognize challenges in treating such patients, leading to more focused management plans that may shorten the duration of hospitalization.