Michiaki Nagai

Prof. Dr. Michiaki Nagai

Department of Cardiology, Hiroshima City Asa Hospital, Hiroshima, Japan
orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 April 2007 in European Psychiatry
Verified
Journal Article
Closed access
Michiaki NagaiMichiaki Nagai
Michiaki Nagai
KKK. Kishi
K. Kishi
SKS. Kato
S. Kato
The insular cortex is located in the centre of the cerebral hemisphere, having connections with the primary and secondary somatosensory areas, anterior cingulate cortex, amygdaloid body, prefrontal cortex, superior temporal gyrus, temporal pole, orbitofrontal cortex, frontal and parietal opercula, primary and association auditory cortices, visual association cortex, olfactory bulb, hippocampus, entorhinal cortex, and motor cortex. Accordingly, dense connections exist among insular cortex neurons. The insular cortex is involved in the processing of visceral sensory, visceral motor, vestibular, attention, pain, emotion, verbal, motor information, inputs related to music and eating, in addition to gustatory, olfactory, visual, auditory, and tactile data. In this article, the literature on the relationship between the insular cortex and neuropsychiatric disorders was summarized following a computer search of the Pub-Med database. Recent neuroimaging data, including voxel based morphometry, PET and fMRI, revealed that the insular cortex was involved in various neuropsychiatric diseases such as mood disorders, panic disorders, PTSD, obsessive-compulsive disorders, eating disorders, and schizophrenia. Investigations of functions and connections of the insular cortex suggest that sensory information including gustatory, olfactory, visual, auditory, and tactile inputs converge on the insular cortex, and that these multimodal sensory information may be integrated there.

20 September 2021 in Hypertension
Verified
Journal Article
Open access
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Rianne De HeusRianne De Heus
Rianne De Heus
CTChristophe Tzourio
Christophe Tzourio
ELEmily Jo Lynn Lee
Emily Jo Lynn Lee
MOMelissa Opozda
Melissa Opozda
AVAndrew D. Vincent
Andrew D. Vincent
Phillip J TullyPhillip J Tully
Phillip J Tully
Research links high blood pressure variability (BPV) with stroke and cerebrovascular disease, however, its association with cognition remains unclear. Moreover, it remains uncertain which BP-derived parameter (ie, variability or mean) holds more significance in understanding vascular contributions to cognitive impairment. We searched PubMed, Embase, PsycINFO, and Scopus and performed a meta-analysis of studies that quantified the association between resting BPV with dementia or cognitive impairment in adults. Two authors independently reviewed all titles, abstracts, and full-texts and extracted data, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-Analysis of Observational Studies in Epidemiology guidelines. Study quality was assessed using the (modified) Newcastle-Ottawa Scale. A multilevel meta-analysis was used, which included effect sizes for both BPV and mean BP, with a combined end point of dementia or cognitive impairment as primary outcome. In the primary analysis, 54 effect sizes were extracted from 20 studies, with a total analytical sample of n=7 899 697. Higher systolic BPV (odds ratio [OR], 1.25 [95% CI, 1.16–1.35]), mean systolic pressure (OR, 1.12 [95% CI, 1.02–1.29]), diastolic BPV (OR, 1.20 [95% CI, 1.12–1.29]), and mean diastolic pressure (OR, 1.16 [95% CI, 1.04–1.29]) were associated with dementia and cognitive impairment. A direct comparison showed that mean BP effect sizes were less strong than BPV effect sizes (OR, 0.92 [95% CI, 0.87–0.97], P <0.01), indicating that the relative contribution of BPV exceeded that of mean BP. Methodological and statistical heterogeneity was high. Secondary analyses were less consistent as to whether BPV and mean BP were differentially associated with dementia subtypes and cognitive domains. Future studies are required to investigate BPV as a target for dementia prevention.

14 December 2020 in The Journal of Clinical Hypertension
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Journal Article
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KKKazuomi Kario
Kazuomi Kario
SHSatoshi Hoshide
Satoshi Hoshide
YCYook‐Chin Chia
Yook‐Chin Chia
PBPeera Buranakitjaroen
Peera Buranakitjaroen
SSSaulat Siddique
Saulat Siddique
JWJi‐Guang Wang
Ji‐Guang Wang
Hypertension is an important public health issue due to its association with a number of serious diseases, including cardiovascular disease and stroke. The importance of evaluating hypertension taking into account different blood pressure (BP) profiles and BP variability (BPV) is increasingly being recognized, and is particularly relevant in Asian populations given the specific features of hypertension in the region (including greater salt sensitivity and a high rate of nocturnal hypertension). Ambulatory BP monitoring (ABPM) is the gold standard for diagnosing hypertension and assessing 24‐hour BP and provides data on several important parameters that cannot be obtained using any other form of BP measurement. In addition, ABPM parameters provide better information on cardio‐ and cerebrovascular risk than office BP. ABPM should be used in all patients with elevated BP, particularly those with unstable office or home BP, or who are suspected to have white‐coat or masked hypertension. ABPM is also an important part of hypertension diagnosis and monitoring in high‐risk patients. ABPM needs to be performed using a validated device and good practice techniques, and has a role both in hypertension diagnosis and in monitoring the response to antihypertensive therapy to ensure strict BP control throughout the 24‐hour period. Use of ABPM in clinical practice may be limited by cost and accessibility, and practical education of physicians and patients is essential. The ABPM evidence and practice points in this document are based on the Hypertension Cardiovascular Outcome Prevention and Evidence (HOPE) Asia Network expert panel consensus recommendations for ABPM in Asia.

17 July 2017 in Journal of Alzheimer’s Disease
Verified
Journal Article
Closed access
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Michiaki NagaiMichiaki Nagai
Michiaki Nagai
KDKeigo Dote
Keigo Dote
MKMasaya Kato
Masaya Kato
SSShota Sasaki
Shota Sasaki
NONoboru Oda
Noboru Oda
ATAkane Tsuchiya
Akane Tsuchiya
While hypertension has been shown to be a risk factor for vascular dementia, several studies have also demonstrated that hypertension also increases the risk of Alzheimer’s disease (AD). Although the relationship between visit-to-visit blood pressure

4 January 2022 in The Journal of Clinical Hypertension
Verified
Journal Article
Open access
PDF file
YZYuqing Zhang
Yuqing Zhang
HMHuanhuan Miao
Huanhuan Miao
YCYook‐Chin Chia
Yook‐Chin Chia
PBPeera Buranakitjaroen
Peera Buranakitjaroen
SSSaulat Siddique
Saulat Siddique
JWJiguang Wang
Jiguang Wang
Cardiovascular disease (CVD) is becoming the most important burden to health care systems in most part of the world, especially in Asia. Aiming at identifying high risk individuals and tailoring preventive treatment, many cardiovascular risk assessment tools have been established and most of them were developed in Western countries. However, these cardiovascular risk assessment tools cannot be used interchangeably without recalibration because of the different risk factor profiles (ie, greater absolute burden of hypertension and lower level of total‐cholesterol in Asians and higher prevalence of metabolic disorders in South Asians) and different CVD profiles (higher ratio of stroke/coronary heart disease in Asians) between Western and Asian populations. Original risk models such as Prediction for ASCVD Risk in China (China‐PAR) and Japan Arteriosclerosis Longitudinal Study (JALS) score have been developed and well validated for specific countries, while most of countries/regions in Asia are using established models. Due to higher incidence of stroke in Asians, risk factors like hypertension should weigh more in cardiovascular risk assessment comparing with Western populations, but their actual proportions should be based on CVD profiles in specific countries/regions. The authors encourage the development of new cardiovascular risk assessment tools for Asians, if possible. Still, modifying established models with native epidemiological data of risk factor as well as CVD is acceptable in regions where health care resources are insufficient.

16 February 2022 in The Journal of Clinical Hypertension
Verified
Journal Article
Open access
PDF file
KKKazuomi Kario
Kazuomi Kario
YCYook‐Chin Chia
Yook‐Chin Chia
SSSaulat Siddique
Saulat Siddique
YTYuda Turana
Yuda Turana
YLYan Li
Yan Li
JWJi‐Guang Wang
Ji‐Guang Wang
Asia is a large continent and there is significant diversity between countries and regions. Over the last 30 years, absolute blood pressure (BP) levels in Asia have increased to a greater extent than those in other regions. In diverse Asia‐Pacific populations, for choosing an Asia‐specific approach to hypertension management is important to prevent target organ damage and cardiovascular diseases. In this consensus document of HOPE Asia Network, we introduce seven action approaches for management of hypertension in Asia.