Revisiting the Clinical Interpretation of CT-Measured Pulmonary Artery-to-Aorta Ratio-The Rotterdam Study.

RATIONALE: The pulmonary artery (PA) diameter-to-aorta ratio (PA:A) ratio is a novel marker in cardiovascular imaging for detecting pulmonary hypertension. However, we question the effect of the varying aorta diameter on the ratio, which complicates the interpretation of the PA:A ratio. OBJECTIVE: Investigate the variability of the PA:A ratio by examining the correlation between PA:A ratio and aorta diameter and by comparing the associations of the PA diameter, aorta diameters, and PA:A ratio. METHODS: We included 2197 participants from the Rotterdam Study who underwent non-contrast multidetector computed tomography to measure the PA and aorta diameters. Pearson correlation coefficient was calculated between the PA:A ratio and aorta diameter. Multiple linear regression analyses were performed to compare the determinants of the individual diameters and PA:A ratio. RESULTS: We found a statistically significant correlation between the PA:A ratio and aorta diameter (r = -0.38, p < 0.001). The PA diameter was statistically significantly associated with, height, weight, diastolic blood pressure, blood pressure medication, prevalence of atrial fibrillation, prevalence of heart failure, and prevalence of stroke (p < 0.05). Except for blood pressure medication, the PA:A ratio had similar determinants compared to the PA diameter but was also statistically significantly associated with sex, and systolic blood pressure (p < 0.05), which were statistically significantly associated with the aorta diameter (p < 0.05). CONCLUSION: The PA:A ratio should not be interpreted without taking into account the variability of the individual components (PA and aorta diameter) according to the anthropomorphic and clinical characteristics.

Hypertensive retinopathy and cardiovascular disease risk: 6 population-based cohorts meta-analysis.

Background: The cardiovascular risk associated with different levels of hypertensive retinopathy, including mild, remains unclear. We performed an individual participant meta-analysis from 6 population-based cohort studies to determine the relationship of hypertensive retinopathy with incident cardiovascular outcomes. Methods: We identified cohort studies that objectively assessed hypertensive retinopathy from photographs, documented incident cardiovascular outcomes, and were population-based. Six studies contributed data from 11,013 individuals at baseline with 5-13 years follow-up. Participants were recruited if they had hypertension and did not have confounding conditions such as diabetic retinopathy. Main outcome measures were incident coronary heart disease (CHD), stroke and a composite endpoint of cardiovascular disease (CHD or stroke). Pooled estimates of incident risk ratios (IRR) were obtained after adjusting for age, gender, systolic blood pressure, serum total cholesterol, high density lipoprotein and smoking. Results: Among eligible participants with hypertension and without diabetes, there were 1018/9662 (10.5%) incident CHD events, 708/11,013 (6.4%) incident stroke events and 1317/9378 (14.0%) incident CVD events. Mild hypertensive retinopathy was associated with increased risk of CVD (IRR 1.13, 95% CI 1.00 to 1.27) and CHD (IRR 1.17, 95% CI 1.02 to 1.34) but not stroke; moderate hypertensive retinopathy was associated with increased risk of CVD (IRR 1.25 95% CI 1.02 to 1.53) but not stroke or CHD individually. Conclusions: In persons with hypertension, both mild and moderate hypertensive retinopathy were associated with higher CVD risk.

Medication compliance in Singaporean patients with Alzheimer's disease

INTRODUCTION@#Singapore has a rapidly ageing population and an increasing prevalence of Alzheimer's disease (AD). Compliance to AD medications is associated with treatment effectiveness. We investigated compliance to acetylcholinesterase inhibitors (AChEIs) and N-methyl-D-aspartate (NMDA) receptor antagonist and treatment persistence among patients seen at the General Memory Clinic of National University Hospital, Singapore. We also identified the reasons for non-compliance.@*METHODS@#Patients seen at the General Memory Clinic between 1 January 2013 and 31 December 2014, who were prescribed AChEIs and NMDA receptor antagonist, were included in this retrospective cohort study. Non-compliance to medications was indirectly measured by failure to renew prescription within 60 days of the last day of medication supplied by the previous prescription. The reasons for non-compliance were identified.@*RESULTS@#A total of 144 patients were included. At one year, 107 patients were compliant to AD medications, while 37 patients were non-compliant. Around 60% of the non-compliant patients discontinued the use of AD medications within the first six months, and the mean persistent treatment period among this group of patients was 10.3 ± 3.5 months. The main reason for non-compliance was patients' and caregivers' perception that memory loss was of lower priority than other coexisting illnesses. Other reasons for non-compliance included side effects of medications (18.9%), perceived ineffectiveness of treatment (16.2%), inability to attend clinic (5.4%) and high cost of medications (2.7%).@*CONCLUSION@#Our findings suggest that the reasons for medication non-compliance can be identified early. Better compliance may be achieved through a multidisciplinary approach to patient education.

Education influences the association between genetic variants and refractive error: a meta-analysis of five Singapore studies.

Refractive error is a complex ocular trait governed by both genetic and environmental factors and possibly their interplay. Thus far, data on the interaction between genetic variants and environmental risk factors for refractive errors are largely lacking. By using findings from recent genome-wide association studies, we investigated whether the main environmental factor, education, modifies the effect of 40 single nucleotide polymorphisms on refractive error among 8461 adults from five studies including ethnic Chinese, Malay and Indian residents of Singapore. Three genetic loci SHISA6-DNAH9, GJD2 and ZMAT4-SFRP1 exhibited a strong association with myopic refractive error in individuals with higher secondary or university education (SHISA6-DNAH9: rs2969180 A allele, ß = -0.33 D, P = 3.6 × 10(-6); GJD2: rs524952 A allele, ß = -0.31 D, P = 1.68 × 10(-5); ZMAT4-SFRP1: rs2137277 A allele, ß = -0.47 D, P = 1.68 × 10(-4)), whereas the association at these loci was non-significant or of borderline significance in those with lower secondary education or below (P for interaction: 3.82 × 10(-3)-4.78 × 10(-4)). The evidence for interaction was strengthened when combining the genetic effects of these three loci (P for interaction = 4.40 × 10(-8)), and significant interactions with education were also observed for axial length and myopia. Our study shows that low level of education may attenuate the effect of risk alleles on myopia. These findings further underline the role of gene-environment interactions in the pathophysiology of myopia.

Hyperuricemia accompanied with changes in the retinal microcirculation in a Chinese high-risk population for diabetes / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the association of retinal vascular calibers with hyperuricemia in a middle-aged and elderly population.</p><p><b>METHODS</b>A cross-sectional design was applied in this study and 869 participants aged =40 years from a high-risk group for diabetes were recruited. All participants received the anthropometrical measurements and laboratory tests. Retinal arteriolar and venular caliber of the participants were measured with a semi-automated system. Hyperuricemia was defined as a serum uric acid level >420 μmol/L in men and >360 μmol/L in women. Linear regression models were used to assess the association of hyperuricemia with retinal vascular calibers. These models were additionally adjusted for age, central obesity, hypertension, dyslipidemia, weekly activity, smoking status, and education.</p><p><b>RESULTS</b>Among the 869 participants, 133 (15.3%) suffered from hyperuricemia. The crude mean serum uric acid level was 312.3 μmol/L (Standard Deviation 79.5); mean concentration was 355.0 μmol/L (SD 75.5) in male participants, and 288.0 μmol/L (SD 71.1) in female participants (age-adjusted difference 58.1 μmol/L, 95% Confidence Internal 48.5, 67.6). After adjusting for additional covariates, male participants with hyperuricemia had 3.77 μm (95% CI -0.46, 8.00) smaller arteriolar caliber and 6.20 μm (95% CI 0.36, 12.04) larger venule than those without hyperuricemia; the corresponding numbers among female participants were 1.57 μm (95% CI -1.07, 4.21) for retinal arteriolar caliber and 2.28 μm (95% CI -1.72, 6.27) for retinal venular caliber.</p><p><b>CONCLUSION</b>Hyperuricemia was associated with smaller retinal arteriolar caliber and larger venular caliber mainly in male participants in this study.</p>

Two peptides derived from ras-p21 induce either phenotypic reversion or tumor cell necrosis of ras-transformed human cancer cells.

PURPOSE: We investigated the effects of two peptides from the ras-p21 protein, corresponding to residues 35-47 (PNC-7) and 96-110 (PNC-2), on two ras-transformed human cancer cell lines, HT1080 fibrosarcoma and MIAPaCa-2 pancreatic cancer cell lines. In prior studies, we found that both peptides block oncogenic, but not insulin-activated wild-type, ras-p21-induced oocyte maturation. When linked to a transporter penetratin peptide, these peptides induce reversion of ras-transformed rat pancreatic cancer cells (TUC-3) to the untransformed phenotype. METHODS: These peptides and a control peptide, linked to a penetratin peptide, were incubated with each cell lines. Cell counts were obtained over several weeks. The cause of cell death was determined by measuring caspase as an indicator of apoptosis and lactate dehydrogenase (LDH) as marker of necrosis. Since both peptides block the phosphorylation of jun-N-terminal kinase (JNK) in oocytes, we blotted cell lysates of the two cancer cell lines for the levels of phosphorylated JNK to determine if the peptides reduced these levels. RESULTS: We find that both peptides, but not control peptides linked to the penetratin sequence, induce phenotypic reversion of the HT-1080 cell line but cause tumor cell necrosis of the MIA-PaCa-2 cell line. On the other hand, neither peptide has any effect on the viability of an untransformed pancreatic acinar cell line, BMRPA1. We find that, while total JNK levels remain constant during peptide treatment, phosphorylated JNK levels decrease dramatically, consistent with the mechanisms of action of these peptides. CONCLUSION: We conclude that these peptides block tumor but not normal cell growth likely by blocking oncogenic ras-p21-induced phosphorylation of JNK, an essential step on the oncogenic ras-p21-protein pathway. These peptides are therefore promising as possible anti-tumor agents.