Kazuyoshi Kobayashi

Dr. Kazuyoshi Kobayashi


Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

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

Representative Publications

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10 June 2019 in BioMed Research International
Verified
Journal Article
Open access
PDF file
STSatoshi Tanaka
Satoshi Tanaka
KAKei Ando
Kei Ando
KKKazuyoshi Kobayashi
Kazuyoshi Kobayashi
TSTaisuke Seki
Taisuke Seki
THTakashi Hamada
Takashi Hamada
SIShiro Imagama
Shiro Imagama
The phase angle, which is measured via bioelectrical impedance analysis (BIA), is a clinically important bioimpedance parameter used for nutritional assessment and evaluating the risk of various diseases, such as locomotive syndrome (LS). It remains unclear if the phase angle is associated with frailty (fragile state of physical and mental health). We therefore examined this association in a large prospective sample. Of 1081 individuals receiving health checkups, 550 (male; 235, female; 365) were enrolled in this study. We applied the Japanese version of the Cardiovascular Health Study criteria to evaluate frailty and administered the 25-Item Geriatric Locomotive Function Scale to diagnose LS. The phase angle was measured via BIA. Multiple logistic regression analysis was used to evaluate the relationship between the phase angle and frailty. For all participants and for each sex, the phase angle was significantly lower among individuals with frailty. After controlling for age, sex, and body mass index, we found that a low phase angle was a significant risk factor of frailty. As a result of multiple regression analysis including other confounding factors, among male participants, a low phase angle was significantly related with both frailty (P = 0.015) and LS (P < 0.001), whereas among female participants, the low phase angle had a stronger association with frailty (P = 0.001) than with LS (P = 0.52). Our findings suggest that a low angle is a risk factor of frailty. Furthermore, among female participants, frailty has a stronger relation with the phase angle than does LS. Therefore, the phase angle may be considered a useful indicator of frailty that does not require lengthy or costly assessment.

2 June 2021 in Scientific Reports
Verified
Journal Article
Open access
PDF file
KKKazuyoshi Kobayashi
Kazuyoshi Kobayashi
KAKei Ando
Kei Ando
TMTomohiro Matsumoto
Tomohiro Matsumoto
KSKoji Sato
Koji Sato
FKFumihiko Kato
Fumihiko Kato
SIShiro Imagama
Shiro Imagama
Meningiomas are benign tumors that are treated surgically. Local recurrence is likely if the dura is preserved, and en bloc tumor and dura resection (Simpson grade I) is recommended. In some cases the dura is cauterized and preserved after tumor resection (Simpson grade II). The purpose of this study was performed to analyze clinical features and prognostic factors associated with spinal meningioma, and to identify the most effective surgical treatment. The subjects were 116 patients (22 males, 94 females) with spinal meningioma who underwent surgery at seven NSG centers between 1998 and 2018. Clinical data were collected from the NSG database. Pre- and postoperative neurological status was defined using the modified McCormick scale. The patients had a mean age of 61.2 ± 14.8 years (range 19–91 years) and mean symptom duration of 11.3 ± 14.7 months (range 1–93 months). Complete resection was achieved in 108 cases (94%), including 29 Simpson grade I and 79 Simpson grade II resections. The mean follow-up period was 84.8 ± 52.7 months. At the last follow-up, neurological function had improved in 73 patients (63%), was stable in 34 (29%), and had worsened in 9 (8%). Eight patients had recurrence, and recurrence rates did not differ significantly between Simpson grades I and II in initial surgery. Kaplan–Meier analysis of recurrence-free survival showed that Simpson grade III or IV, male, and dural tail sign were significant factors associated with recurrence (P < 0.05). In conclusion, Simpson I resection is anatomically favorable for spinal meningiomas. Younger male patients with a dural tail and a high-grade tumor require close follow-up. The tumor location and feasibility of surgery can affect the surgical morbidity in Simpson I or II resection. All patients should be carefully monitored for long-term outcomes, and we recommend lifelong surveillance after surgery.

1 October 2014 in Clinical Neurology and Neurosurgery
Verified
Journal Article
Closed access
KKKazuyoshi Kobayashi
Kazuyoshi Kobayashi
SIShiro Imagama
Shiro Imagama
YMYuji Matsubara
Yuji Matsubara
HYHisatake Yoshihara
Hisatake Yoshihara
KHKenichi Hirano
Kenichi Hirano
NINaoki Ishiguro
Naoki Ishiguro

1 September 2019 in Clinical Neurology and Neurosurgery
Verified
Journal Article
Closed access
MMMasaaki Machino
Masaaki Machino
KAKei Ando
Kei Ando
KKKazuyoshi Kobayashi
Kazuyoshi Kobayashi
MMMasayoshi Morozumi
Masayoshi Morozumi
STSatoshi Tanaka
Satoshi Tanaka
SIShiro Imagama
Shiro Imagama

20 January 2014 in Journal of Orthopaedic Surgery and Research
Verified
Journal Article
Open access
PDF file
KAKei Ando
Kei Ando
SIShiro Imagama
Shiro Imagama
ZIZenya Ito
Zenya Ito
KKKazuyoshi Kobayashi
Kazuyoshi Kobayashi
JUJunichi Ukai
Junichi Ukai
NINaoki Ishiguro
Naoki Ishiguro
The purpose of this study was to describe the radiological outcomes in patients with unilateral instrumented fixation for cervical dumbbell tumors. Fourteen consecutive individuals were included in the present study. We included Eden type II and III tumors in this cohort study and analyzed fixed segment fusion rates, screw failure with multiplanar reconstruction computed tomography (CT) scan radiographs and lateral radiographs with flexion-extension dynamic views, and immediate postoperative and last follow-up radiographs after surgery. The mean follow-up was 105.4 months. There were six men and eight women ranging in age from 32 to 70 years (mean age, 48 years). Twenty pedicle screws (PSs) and 11 lateral mass screws (LMSs) were used in total. There were seven patients with only PSs, four with only LMSs, and three with PSs at C2 and LMSs at C3. PS misplacement occurred in three screws of insertions including two screws with grade 1 misplacement and one screw with grade 2 misplacement, and no grade 3 misplacement occurred. All screws breached the lateral wall with no apparent superior or inferior misplacement. None of the LMSs were misplaced. Fortunately, no complication could be directly attributed to screw insertion. Radiological evidence showed that all patients achieved successful fusion with no screw loosening or breakage. However, two patients who received only LMS fixation had degenerative spondylolisthesis at the upper fusion segment at the last follow-up. Grade 2 PS misplacement occurred in one screw of insertions. Unilateral pedicle screw fixation for cervical dumbbell tumors is a useful surgical method that can successfully fuse vertebrae with good postoperative alignment.

1 June 2015 in Neuroscience
Verified
Journal Article
Open access
HAH. Arima
H. Arima
TOT. Omura
T. Omura
THT. Hayasaka
T. Hayasaka
NMN. Masaki
N. Masaki
MHM. Hanada
M. Hanada
MSMitsutoshi Setou
Mitsutoshi Setou
In this study, we analyzed the spatiotemporal alterations of phospholipid composition in the spinal cord of an amyotrophic lateral sclerosis (ALS) mouse model (G93A-mutated human superoxide dismutase 1 transgenic mice [SOD1(G93A) mice]) using imaging mass spectrometry (IMS), a powerful method to visualize spatial distributions of various types of molecules in situ. Using this technique, we deciphered the phospholipid distribution in the pre-symptomatic stage, early stage after disease onset, and terminal stages of disease in female SOD1(G93A) mouse spinal cords. These experiments revealed a significant decrease in levels of docosahexaenoic acid (DHA)-containing phosphatidylcholines (PCs), such as PC (diacyl-16:0/22:6), PC (diacyl-18:0/22:6), and PC (diacyl-18:1/22:6) in the L5 anterior horns of terminal stage (22-week-old) SOD1(G93A) mice. The reduction in PC (diacyl-16:0/22:6) level could be reflecting the loss of motor neurons themselves in the anterior horn of the spinal cord in ALS model mice. In contrast, other PCs, such as PC (diacyl-16:0/16:0), were observed specifically in the L5 dorsal horn gray matter, and their levels did not vary between ALS model mice and controls. Thus, our study showed a significant decrease in DHA-containing PCs, but not other PCs, in the terminal stage of ALS in model mice, which is likely to be a reflection of neuronal loss in the anterior horns of the spinal cords. Given its enrichment in dorsal sensory regions, the preservation of PC (diacyl-16:0/16:0) may be the result of spinal sensory neurons being unaffected in ALS. Taken together, these findings suggest that ALS spinal cords show significant alterations in PC metabolism only at the terminal stage of the disease, and that these changes are confined to specific anatomical regions and cell types.