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Biomedical subjects

Hitoshi Kubo

Publications and source records attributed to Hitoshi Kubo.

10 recordsLinked to original sources
PubMed2006

Proton magnetic resonance spectroscopy reveals an abnormality in the anterior cingulate of a subgroup of obsessive-compulsive disorder patients.

Numerous neuroimaging studies have suggested that obsessive-compulsive disorder (OCD) patients had a neurobiological abnormality in the frontal-subcortical circuits. On the other hand, there are distinct differences in the responses to pharmacological treatment among OCD patients. In the present study, we measured the concentration of N-acetyl aspartate (NAA), a putative marker of neuronal viability, with proton magnetic resonance spectroscopy (MRS) in OCD patients with different pharmacological responses. Participants comprised 20 patients and 26 healthy control subjects. OCD patients were divided into three groups according to the pharmacological response; responders to a selective serotonin reuptake inhibitor (SSRI) (group A: n=7), responders to SSRI with an atypical antipsychotic (group B: n=8) and non-responders to either SSRI or SSRI with an atypical antipsychotic (group C: n=5). Short echo proton MRS was used to measure NAA concentrations in the anterior cingulate, the left basal ganglia and the left prefrontal lobe of subjects. A significantly lower NAA concentration was observed only in group B compared with control subjects in the anterior cingulate. Our results suggest that a subgroup of OCD patients who respond to an SSRI with an atypical antipsychotic have distinct biological abnormalities in the anterior cingulate.

Adult↗
PubMed2006

The influences of method of calcium correction and the timing of blood collection on application of the K/DOQI Clinical Practice Guidelines for Bone Metabolism and Disease in Japan.

We investigated the treatment of renal osteodystrophy (ROD) in Japan and problems concerning the K/DOQI Guidelines. The subjects were 3698 hemodialysis patients (2328 males and 1370 females) with a mean age of 61.4 years. On average, they had been on hemodialysis for 8.34 years. The serum phosphorus level was <3.5 mg/dL in 5% of the subjects, 3.5-5.5 mg/dL in 49%, 5.6-7.0 mg/dL in 33%, and >7.0 mg/dL in 13%. The serum calcium level was <8.4 mg/dL in 16% of the subjects, 8.4-9.5 mg/dL in 47%, 9.5-10.2 mg/dL in 22%, and >10.2 mg/dL in 15%. The intact PTH level was <150 pg/mL in 57%, 150-300 pg/mL in 27%, and >300 pg/mL in 16% of the patients. The first problem is that correcting Ca is not always performed in clinical fields. The uncorrected calcium level was 9.14+/-0.92 mg/dL, while the corrected calcium level [Ca = Ca + 0.8 x (4-Alb)] was 9.26+/-0.93 mg/dL (P < 0.05). The second problem is that the timing of blood collection is not described in the K/DOQI Guidelines. Subjects with a serum phosphorus level >7.0 mg/dL at 3 days after the previous dialysis were selected for assessment. In these patients, the midweek serum phosphorus level (7.13+/-0.15 mg/dL) at was significantly lower than that (8.11+/-0.15 mg/dL) at the beginning of the next week (P < 0.001). These results suggest that it is necessary to specify the timing of measurement and the method of Ca correction when guidelines for management of ROD are established in the future.

Algorithms↗
PubMed2006

Hemodynamic changes with liver fibrosis measured by dynamic contrast-enhanced MRI in the rat.

PURPOSE: To evaluate the hemodynamic changes of liver cirrhosis in the rat and investigate the relationship between hemodynamic changes and properties of fibrotic change in the liver. MATERIALS AND METHODS: Three rats with cirrhosis induced by thioacetamide (TAA), three with disease induced by carbon tetrachloride (CCl4), and three with no treatment were measured on dynamic MRI using a 1.5T scanner. Compartment and moment analysis were used to quantitate hemodynamic changes. RESULTS: Compartment model analysis showed that increased transition speed from vessels to the liver correlated with grade of liver fibrosis. Moment analysis demonstrated that decrease of area under the curve (AUC), mean residence time (MRT), variance of residence time (VRT), half life (T1/2) and increased total clearance (CL) correlated with grade of liver fibrosis. CONCLUSIONS: Hemodynamic changes in injured fibrotic liver may be influenced by the grade of fibrosis. Compartment model and moment analysis may be useful for evaluating hemodynamic changes in injured liver.

Animals↗
PubMed2005

[A Study of uncertainty factors in cross calibration of dosimeter for diagnostic X-rays].

Although patient exposure has been increasing in recent years, few institutions have dosimeters and are able to ascertain patients' exposure dose. Internationally, however, it is necessary to adopt safety levels for patient exposure doses, and guidance levels have been introduced. Therefore, the need for measurement in areas of x-ray diagnosis has been increasing. As a result, several societies concerned with radiation dose have been endeavoring to establish a calibration system of radiation measurement and a dosimeter calibration system, which are the basics of radiation protection. Ten regional centers for standardization of doses in x-ray diagnosis were established and have begun trials relating to dosimeter cross calibration. Our institution, as one of these centers, has instituted a trial. In this study, the cross-calibration field, the reliability of the cross-calibration skill of our regional center, and the standard uncertainty of cross calibration were investigated. As a consequence of the investigation, it was determined that our cross-calibration field follows the protocol of the Japanese Society of Radiological Technology, the difference between calibration factor/cross calibration factor obtained by JQA and our regional center is within 2.5%, and the expanded uncertainty of our cross calibration is about 7.2% (k=2).

Calibration↗
PubMed2005

[Significance of shunt efficacy decision of SPECT on idiopathic normal pressure hydrocephalus].

PURPOSE: The purpose of this study was to investigate the significance of the shunt-effect evaluation of SPECT in idiopathic normal pressure hydrocephalus (iNPH). SUBJECTS AND METHODS: The subjects were 15 patients with possible iNPH, aged 62-83 (mean 75.3, the ratio of males to females to 6:9), who were treated at our department during the period from June to September, 2004. All patients received the lumbar tap test (LTT) at the outpatient section before surgery. An L-P shunt was conducted on patients whose the LTT positive or negative with cerebrospinal fluid outflow resistance value (Ro) was 10 mmHg/ml/min. or higher patients. As for SPECT, a 3D-SSP Z-score, as well as an mCBF, was conducted before and after the LTT and within one month after surgery. Comparisons were made for (1) the shunt effect, (2) mCBF before and after the LTT and after surgery, (3) mean cerebral blood flow increase rate (mIR) after the LTT, and (4) 3D-SSP before and after surgery. RESULTS: (1) The shunt was effective for all the patients. (2) The mCBF levels was 30.8 +/- 4.02 ml/100 g/min. before the LTT, 37.1 +/- 100 g/min. after the LTT, and 38.6 +/- 3.4 ml/100 g/min. after surgery. A significant increase in mCBF was observed both after the LTT and after surgery (p < 0.05). (3) The mean mIR after the LTT was 21.2 +/- 8.01%, with all the patients showing 10% or higher. (4) The ischemic patterns in the SD-SSP Z-score before surgery were the frontal type (F: 10 cases, 66.7%), the occipitotemporal type (OT: 3 cases, 20%), and the mixed type (M: 2 cases, 13.3%), but not the parietal localized type. The post-operative course showed no-change in 4 cases, disappearance-reduction in 9 cases, and shift to OT in 2 cases. CONCLUSION: The evaluation factors in the measurement of the cerebral blood flow for evaluation of the shunt effect were the following two items. (1) The mIR of mCBF after the LIT was 10% or higher. (2) As for the preoperative cerebral ischemic patterns, there were many F cases and no parietial localized types found.

Aged↗
PubMed2004

Encapsulating peritoneal sclerosis in Japan: a prospective, controlled, multicenter study.

BACKGROUND: Encapsulating peritoneal sclerosis (EPS) is recognized as a rare but serious complication of peritoneal dialysis (PD). The aim of this study was to determine the incidence, clinical features, and mortality rate of EPS. METHODS: The authors requested the registration of all PD patients in facilities across Japan where more than 10 patients were treated with PD in this prospective multicenter study. During the 4-year study, the incidence of EPS was observed in the enrolled patients. RESULTS: A total of 1,958 patients who were treated with PD in 57 facilities were followed up from April 1999 through March 2003. EPS occurred in 48 patients, corresponding to an overall incidence of 2.5%. In 33 of the 48 (68.8%) patients, EPS was found after discontinuation of PD. The incidence (and mortality rate) of EPS was 0%, 0.7% (0%), 2.1% (8.3%), 5.9% (28.6%), 5.8% (61.5%), and 17.2% (100%) in patients who had undergone PD for 3, 5, 8, 10, 15, and more than 15 years, respectively. The recovery ratio with total parenteral nutrition, corticosteroids and surgical treatment were 0%, 38.5%, and 58.3%, respectively. Eighteen patients (37.5%) died, 22 (45.8%) recovered, and the status of the other 8 (16.7%) remained unchanged. CONCLUSION: The results of this prospective multicenter study showed that the incidence of EPS was 2.5% within a 4-year observation period and that two thirds of the cases were diagnosed after discontinuation of PD. Because of the current progress in diagnostic technology and therapeutic methodology, it appears that PD can be continued successfully with an acceptable, low risk for EPS for at least 8 years, whereas stricter caution is required for patients receiving PD for longer periods.

Adult↗
PubMed2002

[Long-standing high-transport membrane as a risk factor for EPS development after PD withdrawal: an analysis based on changes in peritoneal function during and after CAPD withdrawal].

The pathophysiology of encapsulating peritoneal sclerosis (EPS) that develops after withdrawal from long-standing dependence on CAPD remains unclear. The aim of this study was to clarify the risk factors for EPS as expressed in the peritoneal function. Fourteen patients who had shifted to standard hemodialysis after long-term CAPD (average, 105 months) were studied: 3 developed EPS after PD withdrawal while 11 did not. Analysis of the data obtained from the peritoneal equilibration test (PET) revealed that: (1) the dialysate/plasma creatinine ratio (D/Pcr) was significantly higher in the EPS group than in the non-EPS group during the course of PD as well as after PD withdrawal; and (2) eight patients, including the 3 with EPS, were classified as being in a high-transport membrane state (HTS) at PD withdrawal. The duration of HTS during PD was longer in those patients with EPS. During the periods after PD withdrawal, none of these EPS patients recovered from HTS, whereas 4 of the 5 non-EPS patients did. These data suggest that long-standing HTS during the course of PD as well as post-withdrawal, may be risk factors for EPS development. For this reason, it is indicated that PET has clinical relevance in examining sequential changes in peritoneal function and in detecting those patients at risk of EPS.

Adult↗
PubMedDate not supplied

Reproducibility of metabolite concentration evaluated by intraclass correlation coefficient using clinical MR apparatus.

OBJECTIVE: The purpose of this study was to evaluate the reproducibility of in vivo quantitative proton MR spectroscopy (MRS) by repeated-measure analysis of variance and intraclass correlation coefficient (ICC) including assessment of both inter- and intrasubject variation. METHODS: The concentration of metabolites was quantified using long-TR and short-TE stimulated-echo acquisition mode sequences with a quadrature head coil. All preparation procedures for MRS measurement except volume of interest determination were done by an automatic preparation scanning system equivalent to a clinical setting. Analyses were conducted by an LCModel running based on our original basis set by two different reference methods. RESULTS: The ICC showed a good correlation (r = 0.61-0.99) in any metabolite and almost the same value between the two different reference methods, but the concentration of myoinositol had a large intersubject variation. CONCLUSION: Our results suggest that the reproducibility of quantified metabolite concentration is acceptable in the clinical setting regardless of the reference method, although quantified values may have different intersubject variations.

Adult↗
PubMedDate not supplied

Relationships between head fixation pins for radiosurgery and the skull bone--usefulness of a torque wrench.

BACKGROUND: In stereotactic radiosurgery (SRS), fixation devices are secured to the patient's head with pins. However, there have been no standards for the use of such pins, which must be inserted with appropriate torque based on the surgeon's clinical judgment. Therefore, the pins may sometimes be tightened excessively and penetrate too deeply into the patient's skull. PURPOSE: To improve safety in SRS, a torque wrench was used for pin insertion. The usefulness of the torque wrench was then evaluated by examining the relationships between the pins and skull bone and identifying differences according to the wrench used and the patient's bone thickness. METHODS: CT images of patients who had previously undergone SRS were used to assess the relationships between the pins and skull bone. Differences according to the wrench used and pin insertion site were investigated. RESULTS: Compared with a standard wrench, use of the torque wrench decreased the insertion depth of pins in the skull bone. In terms of site, pins in the forehead were inserted more deeply. No differences related to the frontal sinus were observed. CONCLUSION: The use of a torque wrench improved safety during pin insertion for SRS procedures.

Adolescent↗