Machiko Oka

Dr. Machiko Oka


Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

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

Representative Publications

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19 December 2019 in BMC Nephrology
Verified
Journal Article
Open access
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RMRyo Matsuura
Ryo Matsuura
SHSumi Hidaka
Sumi Hidaka
Takayasu OhtakeTakayasu Ohtake
Takayasu Ohtake
YMYasuhiro Mochida
Yasuhiro Mochida
クIクニヒロ Ishioka
クニヒロ Ishioka
Shuzo KobayashiShuzo Kobayashi
Shuzo Kobayashi
Background: Critical limb ischemia (CLI) and intradialytic hypotension (IDH) are common complications in patients on hemodialysis (HD). However, limited data are available on whether IDH is related to CLI in these patients. The aim of this retrospective study was to evaluate whether IDH is a risk factor for CLI in HD patients.Methods: We examined the frequency of IDH in 147 patients who received HD between January 1 and June 30, 2012. Blood pressure was measured during HD every 30 min and IDH was defined as a ≥ 20 mmHg fall in systolic blood pressure compared to 30 min before and a nadir intradialytic systolic blood pressure < 90 mmHg. The primary study outcome was newly developed CLI requiring revascularization treatment or CLI-related death. We assessed the association of IDH with outcome using a multivariable subdistribution hazard model with adjustment for male, age, smoking and history of cardiovascular disease.Results: The median follow-up period was 24.5 months. Fifty patients (34%) had episodes of IDH in the study entry period. During follow-up, 14 patients received endovascular treatment and CLI-related death occurred in 1 patient. Factors associated with incident CLI in univariate analysis were age, smoking, diabetes mellitus, peripheral arterial disease, history of cardiovascular disease, and IDH. IDH was significantly associated with the outcome with the subdistribution hazard ratio of 3.13 [95% confidence interval, 1.05–9.37].Conclusions: IDH was an independent risk factor for incident CLI in patients on HD.

26 June 2014 in Therapeutic Apheresis and Dialysis
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Journal Article
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RIRei Isshiki
Rei Isshiki
Shuzo KobayashiShuzo Kobayashi
Shuzo Kobayashi
MIMasao Iwagami
Masao Iwagami
DTDaimu Tsutumi
Daimu Tsutumi
YMYasuhiro Mochida
Yasuhiro Mochida
SHSumi Hidaka
Sumi Hidaka

6 February 2023 in Journal of Clinical Medicine
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Journal Article
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Takayasu OhtakeTakayasu Ohtake
Takayasu Ohtake
AMAyaka Mitomo
Ayaka Mitomo
MYMizuki Yamano
Mizuki Yamano
TSToshihiro Shimizu
Toshihiro Shimizu
YMYasuhiro Mochida
Yasuhiro Mochida
Shuzo KobayashiShuzo Kobayashi
Shuzo Kobayashi
Lower limbs’ arterial calcification is significantly associated with the clinical severity of lower extremity artery disease (LEAD) in patients undergoing hemodialysis (HD). However, the association between arterial calcification of the lower limbs and long-term clinical outcomes in patients on HD has not been elucidated. Calcification scores of the superficial femoral artery (SFACS) and below-knee arteries (BKACS) were quantitatively evaluated in 97 HD patients who were followed for 10 years. Clinical outcomes, including all-cause and cardiovascular mortality, cardiovascular events, and limb amputation were evaluated. Risk factors for clinical outcomes were evaluated using univariate and multivariate Cox proportional hazard analyses. Furthermore, SFACS and BKACS were divided into three groups (low, middle, and high), and their associations with clinical outcomes were evaluated using Kaplan–Meier analysis. SFACS, BKACS, C-reactive protein, serum albumin, age, diabetes, presence of ischemic heart disease, and critical limb-threatening ischemia were significantly associated with 3-year and 10-year clinical outcomes in the univariate analysis. Multivariate analysis showed that SFACS was an independent factor associated with 10-year cardiovascular events and limb amputations. Kaplan–Meier life table analysis showed that higher SFACS and BKACS levels were significantly associated with cardiovascular events and mortality. In conclusion, long-term clinical outcomes and the risk factors in patients undergoing HD were evaluated. Arterial calcification of the lower limbs was strongly associated with 10-year cardiovascular events and mortality in patients undergoing HD.

5 March 2012 in Therapeutic Apheresis and Dialysis
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Journal Article
Closed access
PDF file
MOMachiko Oka
Machiko Oka
Takayasu OhtakeTakayasu Ohtake
Takayasu Ohtake
YMYasuhiro Mochida
Yasuhiro Mochida
クIクニヒロ Ishioka
クニヒロ Ishioka
KMKyoko Maesato
Kyoko Maesato
Shuzo KobayashiShuzo Kobayashi
Shuzo Kobayashi

7 April 2020 in Clinical and Experimental Nephrology
Verified
Journal Article
Open access
PDF file
YMYasuhiro Mochida
Yasuhiro Mochida
Takayasu OhtakeTakayasu Ohtake
Takayasu Ohtake
クIクニヒロ Ishioka
クニヒロ Ishioka
MOMachiko Oka
Machiko Oka
KMKyoko Maesato
Kyoko Maesato
Shuzo KobayashiShuzo Kobayashi
Shuzo Kobayashi
Background: Approximately, 20–70% of patients with cholesterol crystal embolism (CCE) have eosinophilia. However, it remains unknown how eosinophilia influences renal prognosis in patients with CCE. In this study, we investigated the association between eosinophil count (Eo) and renal prognosis in CCE patients on steroid therapy. Methods: The present study is a single-centered retrospective cohort study in patients with renal dysfunction and CCE from April 2007 to May 2018. This study included the patients who were treated with neither maintenance dialysis nor steroid before CCE diagnosis, and followed-up for kidney function until November 2019. We assessed whether eosinophilia at the time of CCE diagnosis was related to renal death after treating with steroid therapy. Results: Thirty patients with pathologically diagnosed CCE were enrolled and followed-up for 11.0 (5.2–43.4) months. There were significant differences in the white blood cell count (p = 0.01), hemoglobin (p = 0.009), serum creatinine levels (p = 0.008), phosphate (p = 0.049), and Eo (p = 0.008) between the renal survival and renal death groups. Using the receiver operating characteristic curve analysis with Youden index, Eo of 810/µL showed 100% sensitivity and 69.6% specificity for detecting renal death (area under the curve: 0.839). Comparing the outcomes in patients having Eo ≥ and < 810/µL using the log-rank test, there is a significantly higher renal death rate in CCE patients with Eo ≥ 810/µL (p = 0.0016). Conclusion: Higher eosinophilia was a prognostic risk factor for renal death in the patients with CCE.

9 February 2006 in Nephrology Dialysis Transplantation
Verified
Journal Article
Open access
PDF file
Takayasu OhtakeTakayasu Ohtake
Takayasu Ohtake
Shuzo KobayashiShuzo Kobayashi
Shuzo Kobayashi
KOKOJI OKAMOTO
KOJI OKAMOTO
MOMachiko Oka
Machiko Oka
KMKyoko Maesato
Kyoko Maesato
HMHidekazu Moriya
Hidekazu Moriya