Biomedical subjects

Kosuke Narita

Publications and source records attributed to Kosuke Narita.

6 recordsLinked to original sources

PubMed2006

Association between trait anxiety and endothelial function observed in elderly males but not in young males.

BACKGROUND AND OBJECTIVES: Endothelial function plays a key role in determining the clinical manifestations of atherosclerosis. Recent reports have shown that healthy elderly subjects with higher trait anxiety tend to have heightened risks of atherosclerotic lesions and cardiovascular disease. The present study was intended to examine whether an association exists between trait anxiety and endothelial function in healthy young and elderly subjects. METHODS: This study examined 26 young male and 30 elderly male subjects using brachial artery flow-mediated dilation (FMD) - a non-invasive ultrasound method - to evaluate endothelial function by measuring the dilation responses of vascular smooth muscle to the nitric oxide produced by endothelial cells following hyperemia. RESULTS: A significant negative correlation was observed between the State and Trait Anxiety Inventory (STAI)-trait score as a parameter of anxiety and the percentage change of FMD (%FMD) in the elderly subjects, but not in the young subjects. The elderly subjects showed significantly lower %FMD than the young subjects. CONCLUSION: These results suggest the possibility that trait anxiety is a predisposing risk factor for cardiovascular damage that might, over a long period, induce atherosclerotic lesions.

Adult↗

PubMed2006

Multifractal analysis of deep white matter microstructural changes on MRI in relation to early-stage atherosclerosis.

Multifractal analysis based on generalized concepts of fractals has been applied to evaluate biological tissues composed of complex structures. This type of analysis can provide a precise quantitative description of a broad range of heterogeneous phenomena. Previously, we applied multifractal analysis to describe heterogeneity in white matter signal fluctuation on T2-weighted MR images as a new method of texture analysis and established Deltaalpha as the most suitable index for evaluating white matter structural complexity (Takahashi et al. J. Neurol. Sci., 2004; 225: 33-37). Considerable evidence suggests that pathophysiological processes occurring in deep white matter regions may be partly responsible for cognitive deterioration and dementia in elderly subjects. We carried out a multifractal analysis in a group of 36 healthy elderly subjects who showed no evidence of atherosclerotic risk factors to examine the microstructural changes of the deep white matter on T2-weighted MR images. We also performed conventional texture analysis, i.e., determined the standard deviation of signal intensity divided by mean signal intensity (SD/MSI) for comparison with multifractal analysis. Next, we examined the association between the findings of these two types of texture analysis and the ultrasonographically measured intima-media thickness (IMT) of the carotid arteries, a reliable indicator of early carotid atherosclerosis. The severity of carotid IMT was positively associated with Deltaalpha in the deep white matter region. In addition, this association remained significant after excluding 12 subjects with visually detectable deep white matter hyperintensities on MR images. However, there was no significant association between the severity of carotid IMT and SD/MSI. These results indicate the potential usefulness of applying multifractal analysis to conventional MR images as a new approach to detect the microstructural changes of apparently normal white matter during the early stages of atherosclerosis.

Aged↗

PubMed2006

Plasma levels of adiponectin and tumor necrosis factor-alpha in patients with remitted major depression receiving long-term maintenance antidepressant therapy.

Adiponectin, an adipose tissue-specific plasma protein, is involved in insulin sensitization and has anti-atherosclerotic properties, whereas tumor necrosis factor-alpha (TNF-alpha), a pro-inflammatory protein, plays important roles in inflammatory endothelial injury and atherosclerotic changes. It has been reported that adiponectin and TNF-alpha inhibit each other's expression and production in adipocytes. Several in vitro studies indicated that antidepressant medications decreased the production of pro-inflammatory cytokines including TNF-alpha, but the effect of antidepressants on the expression of adiponectin is still unknown. We examined the plasma levels of TNF-alpha and adiponectin in patients with remitted depression receiving maintenance antidepressant therapy for longer than half a year, and compared the levels with those in healthy controls. The plasma levels of TNF-alpha and adiponectin in the remitted depression group were significantly lower and higher than those in the control group, respectively. This preliminary cross-sectional study suggests the possibility that maintenance antidepressant therapy may have anti-inflammatory effects and prevent the development of atherosclerosis.

Adiponectin↗

PubMed2006

Interactions among higher trait anxiety, sympathetic activity, and endothelial function in the elderly.

Negative psychological characteristics have been recognized as independent risk factors of cardiovascular disease (CVD). The purpose of this study was to evaluate the influence of depression and anxiety on cardiac autonomic function and endothelial function in healthy elderly subjects. Forty-six healthy elderly volunteers (mean age 60.8 years) were enrolled in this study. Cardiac autonomic function was assessed by spectral analysis of heart rate variability (HRV) with the head-up tilt test. Brachial artery endothelium-dependent flow-mediated dilation (FMD) was measured using high-resolution ultrasound. A significant positive correlation was observed between the State and Trait Anxiety Inventory (STAI)-trait score as a parameter of anxiety and HRV sympathetic modulation in the supine position (baseline), and a significant negative correlation between this score and the head-up-induced HRV sympathetic response from the baseline. The STAI-trait score also showed a significant negative correlation with the percent change of FMD (%FMD). Analysis using structural equation modeling showed that higher trait anxiety reduced %FMD via abnormalities of sympathetic activity. On the other hand, psychometric parameters of depression were not associated with any HRV component or %FMD. These results suggest that there are specific interactions among higher trait anxiety, abnormalities of sympathetic activity, and endothelial dysfunction. This finding may be useful in clarifying the pathophysiological mechanism by which anxiety is associated with increased risks for atherosclerosis and CVD.

Aged↗

PubMed2006

White coat phenomenon, anxiety and endothelial function in healthy normotensive elderly subjects.

OBJECTIVE: The white coat phenomenon (WCP) is a blood pressure (BP) elevation specifically observed in the clinical setting. Though WCP has been suggested to associate with emotional responses such as anxiety or with cardiovascular complications, its pathogenesis and clinical significance are unclear. We studied the possible association between WCP and anxiety or vascular function in normotensive elderly subjects without major cardiovascular risk factors. METHODS: As a parameter of anxiety, the State and Trait Anxiety Inventory (STAI) was used. WCP was evaluated by calculating the difference between the clinic BP and mean daytime ambulatory BP. As parameters of vascular function, brachial artery endothelium-dependent flow-mediated dilation (FMD) and the endothelium-independent dilation response to sublingual glyceryl trinitrate (GTN) were measured using high-resolution ultrasound. RESULTS: Using confounding factors as covariates, no association was observed between WCP and the STAI-trait or STAI-state score. There was a significant negative association between WCP and the percent change of FMD but no association between WCP and the percent change of GTN. CONCLUSION: WCP in the healthy normotensive elderly subjects may reflect a decrease in endothelial function, i.e. initial stage atherosclerosis, rather than anxiety.

Aged↗

PubMed2002

A case of diffuse neurofibrillary tangles with calcification.

We report a 79-year-old female with atypical senile dementia with Fahr-type calcification. The patient started to show memory disturbance at the age of 75 years, followed by visual hallucination, stereotypy, personality changes such as irritability, aggression and disinhibition. Brain computed tomography (CT) demonstrated bilateral and symmetric calcification of the basal ganglia and thalamus. Magnetic resonance imaging (MRI) revealed diffuse cortical atrophy pronounced in the fronto-temporal areas. On MRI T1-weighted images the calcified areas showed a mixture of low- and high-intensity signals. Based on the overlapping clinical symptoms of Alzheimer's disease and Pick's disease, together with the brain CT and MRI findings, we clinically diagnosed the patient as having 'diffuse neurofibrillary tangles with calcification' (DNTC). The characteristics of psychiatric symptoms and neuroradiological findings in DNTC are discussed.

Aged↗