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Biomedical subjects

S Kuribayashi

Publications and source records attributed to S Kuribayashi.

At least 19 recordsLinked to original sources
PubMed2006

Species differences in hydrolase activities toward OT-7100 responsible for different bioavailability in rats, dogs, monkeys and humans.

OT-7100 (5-n-butyl-7-(3,4,5-trimethoxybenzoylamino)pyrazolo[1,5-a] pyrimidine) is an amide moiety-bearing pyrazolopyrimidine derivative with a potential analgesic effect. To determine the factors responsible for observed species differences in the bioavailability of this drug, human and experimental animal samples were used to investigate in vitro microsomal and cytosolic hydrolase activities in the liver and small intestine vis-à-vis the pharmacokinetics of OT-7100. The AUC(0-t) values of OT-7100 after oral administration in rats, dogs and monkeys were 0.163, 0.0383 and 0.00147 microg h ml(-1) divided by mg kg(-1), respectively. The bioavailabilities of OT-7100 after oral administration in rats, dogs and monkeys were 36, 17 and 0.3%, respectively. The plasma concentration-time profiles of intravenously administrated OT-7100 in rats, dogs and monkeys were similar. The hydrolase activities toward OT-7100 in liver microsomes or cytosol were approximately similar in rats, dogs, monkeys and humans. In contrast, hydrolase activities of small intestinal microsomes from monkeys were higher (36.1 ng mg protein(-1) min(-1)) than those of rats, dogs and humans (5.4, 1.4 and 4.3 ng mg protein(-1) min(-1), respectively). These results suggest that the primary factor influencing first-pass metabolism for the OT-7100 is enzymatic hydrolysis in the small intestine. This information provides an important index for extrapolating the pharmacokinetics of drugs in humans using studies on monkeys.

Animals↗
PubMed2005

PROPELLER diffusion-weighted magnetic resonance imaging of acute spinal epidural hematoma.

We present the case of an 86-year-old female with spontaneous spinal epidural hematoma. Although T1- and T2-weighted images showed the dilated posterior epidural space at the cervical spine, this finding was non-specific on conventional magnetic resonance imaging obtained 15 h after the onset of symptoms. Diffusion-weighted imaging with the use of periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER), which clearly revealed the high intensity hematoma, was useful for detection and diagnosis of acute spinal epidural hematoma.

Acute Disease↗
PubMed2003

Abnormal response to sodium channel blockers in patients with Brugada syndrome: augmented localised wall motion abnormalities in the right ventricular outflow tract region detected by electron beam computed tomography.

OBJECTIVE: To investigate the relation between the wall motion abnormalities and sodium channel abnormalities in cases of the Brugada syndrome. DESIGN: Consecutive prospective case-control study in a single hospital. SETTING: Tertiary referral centre. PATIENTS: 13 consecutive patients with Brugada syndrome and 13 age and sex matched control subjects. INTERVENTIONS: Each subject underwent electron beam computed tomography (EBT) and a 12 lead ECG before and after disopyramide injection. MAIN OUTCOME MEASURES: QRS width and the magnitude of ST segment elevation in the 12 lead ECG; wall motion by EBT. RESULTS: After disopyramide, EBT revealed deterioration of focal wall motion abnormalities in the right ventricular outflow tract region in eight of the 13 patients (62%). Prolongation of the QRS width after disopyramide injection in lead V2, which usually reflects the electrical activity in right ventricular outflow tract region, was greater in these eight patients (p < 0.01) than in the other five patients, in whom wall motion did not change after disopyramide. The degree of augmentation of ST segment elevation did not differ significantly between the two groups CONCLUSIONS: The deterioration of wall motion abnormalities in the right ventricular outflow tract region after disopyramide suggests the presence of functional abnormalities of the sodium channel. Some patients with Brugada syndrome may have arrhythmogenic substrates with abnormal responses to sodium channel blockers.

Adult↗
PubMed2002

Simultaneous removal of nitrogen and phosphorus with A2/O process using immobilized media.

It is necessary to introduce nitrogen and phosphorus removal processes in the existing wastewater treatment plants of Fukuoka City to improve the water quality of Hakata Bay. An A2/O (anaerobic-anoxic-oxic) process using immobilized media is proposed here, as a high-end technology to meet stricter discharge standards when faced with treatment space limitations. In order to investigate the applicability of the process, a pilot-scale study using municipal wastewater was conducted. Fluidized immobilization media were added to the aerobic reactor to maintain a high concentration of nitrifying bacteria and nitrification rate. Relationships between nutrient removal performance and varied operating conditions were examined. The results of the pilot plant test indicated that the process performs well for removal of nitrogen and phosphorus. Under the condition of HRT = 8 hr, it was possible to obtain an effluent water quality as follows: T-N<8.0 mg/L; T-P<1.0 mg/L. It was observed that reaction time needed for a complete nitrification was shortened by the addition of immobilized media to the aerobic reactor, and longer reaction time would be needed for a completed phosphorus uptake process other than complete nitrification in an aerobic tank. Therefore, the phosphorus uptake rate, as well as nitrification process, should be considered as one of the important factors affecting the design parameters of an aerobic reactor.

Bacteria, Aerobic↗
PubMed2001

Localized right ventricular morphological abnormalities detected by electron-beam computed tomography represent arrhythmogenic substrates in patients with the Brugada syndrome.

AIMS: This study was designed to determine, using electron-beam CT, whether there are morphological abnormalities in patients with the Brugada syndrome and to elucidate the relationship between those abnormalities and arrhythmogenesis. METHODS AND RESULTS: Twenty-six consecutive patients with the Brugada syndrome and 23 age- and gender-matched control subjects (controls) were evaluated for morphological abnormalities using electron beam CT. Electron beam CT demonstrated morphological abnormalities of the right ventricle in 21 (81%) of 26 patients, but in only two (9%) of 23 controls. The sites of morphological abnormalities were the right ventricular outflow tract area in 17 patients and the inferior wall of the right ventricle in four patients. Of the seven patients with monoform premature ventricular contractions recorded only in the acute phase, four of the five patients with premature ventricular contractions from the right ventricular outflow tract area had morphological abnormalities in the right ventricular outflow tract area, and the other two patients with premature ventricular contractions from the inferior wall of the right ventricle had morphological abnormalities in the inferior wall of the right ventricle. CONCLUSION: The sites of morphological abnormalities detected by electron beam CT in patients with the Brugada syndrome were related to the origins of premature ventricular contractions recorded only in the acute phase, which may trigger ventricular fibrillation. These morphological abnormalities may be related to arrhythmogenic substrates in patients with the Brugada syndrome.

Adult↗
PubMed2001

[Angiographic findings of hemodialysis access insufficiency].

One hundred forty-six angiographic findings of malfunctioning internal arteriovenous fistulas without any history of interventional procedures were reviewed. Angiographies demonstrated 110 cases of stenosis, 72 of occlusion, 5 of venous varicosity, and 13 of venous aneurysm. Of 182 stenotic lesions, 118 (65%) lesions (74 venous stenoses: 67%; 44 venous occlusions: 61%) were revealed within five centimeters of anastomoses. In 4 of 5 cases of varicosity, proximal venous occlusions were demonstrated. On the other hand, interventional procedures were performed in 81 cases of stenoses and 14 of occlusions in the manner of PTA and fibrinolysis. The initial success rate was 90% in stenotic lesions and 71% in occlusive lesions, not a statistically significant difference. Furthermore, there was no statistically significant difference in initial success rates according to anatomical location and lesion length. Although there was no statistically significant difference according to the angiographic findings of lesions, we would like to emphasize the importance of correct understanding of anatomical changes in the dialysis shunt and of early intervention to improve the initial success rate of PTA.

Adolescent↗
PubMed2001

[Fatty liver quantification with line scan echo planar spectroscopic imaging (LSEPSI)].

INTRODUCTION: Although fatty infiltration of liver is a benign process that generally results from chronic alcohol uptake or obesity, such lifestyle factors may lead to chronic disease. Measuring the fat concentration in liver may therefore prove useful in assessing disease status. In this study, we report the usefulness of line scan echo planar spectroscopic imaging (LSEPSI) for this problem. METHODS: Rapid successive column sampling was accomplished using orthogonal slice-selective 90 degrees and 180 degrees pulses and echo planar spectral/spatial encodings. Phantom and clinical studies of 13 patients suspected of having fatty liver were carried out with LSEPSI. Estimated fat fractions obtained with LSEPSI were compared with ultrasound findings. RESULTS: The results showed a good correlation between the actual fat content of phantoms and the estimated fat fraction obtained with LSEPSI (r = 0.95). In the clinical study, the estimated fat fraction tended to rise as the US grade of fatty liver increased. DISCUSSION: LSEPSI is largely free from T1 and T2 relaxation owing to its infinite TR and minimal T2 weighting. Thus, there is no need for relaxation analysis. In addition, the lack of phase encoding reduces motion-related ghosting artifacts. Rapid fat/water spectral quantification of liver with this technique is useful for fatty liver assessment in a clinical setting.

Adult↗
PubMed2000

Design of a unique PCR primer for detection of oral HPV infection.

Human papillomavirus (HPV) has been known as a pathogen of oral dysplasia. However, suitable PCR primers for the detection of oral HPV infection have not been reported. The aim of this study was to design unique consensus primers. The consensus primers were designed by homologues analyses between subtypes 2, 6, 11, 13, 16, 18, 30, 32 and 58, which frequently infect the oral membrane. PCR, with our designed primer, detected HPV DNA subtypes 2, 6, 11, 16, 18 and 58, and also showed PCR product from a clinical papilloma sample. These results indicate that our designed consensus primer can be used for the study of the relationships between oral disease and HPV infection.

Consensus Sequence↗
PubMed2000

Correlation between severity of pulmonary arterial hypertension and 123I-metaiodobenzylguanidine left ventricular imaging.

UNLABELLED: It remains unclear whether cardiac sympathetic nervous function is disturbed in patients with pulmonary arterial hypertension (PH) and how sympathetic dysfunction is related to PH. METHODS: In this study, (123)I-metaiodobenzylguanidine (MIBG) imaging of the heart, which reveals the sympathetic innervation of the left ventricle, was performed in 7 healthy volunteers without cardiopulmonary disease (control subjects); 55 patients with PH, including 27 with chronic thromboembolic pulmonary hypertension (CTEPH) of major vessels; and 28 patients with primary pulmonary hypertension (PPH). RESULTS: Cardiac (123)I-MIBG uptake, assessed as the heart-to-mediastinum activity ratio (H/M), was significantly lower in the CTEPH and PPH groups compared with that in the control group (P < 0.01). Myocardial MIBG turnover, expressed as the washout rate (WR [%]) from 15 to 240 min, was significantly higher in the CTEPH and PPH groups than that in the control group (P < 0.01). In the PPH group, H/M and WR values of MIBG correlated with the severity of pulmonary hypertension (represented by total pulmonary vascular resistance determined by right heart catheterization), the right ventricular ejection fraction determined by electron beam CT, and other variables but did not correlate well in the CTEPH group. In both groups, patients with H/M > or = 2.0 showed better cumulative survival than did those with H/M < 2.0 (P < 0.05). CONCLUSION: Patients with PH have significant left ventricular myocardial sympathetic nervous alteration. (123)I-MIBG imaging of the heart is useful for assessing the severity of pulmonary hypertension caused by PPH or CTEPH.

3-Iodobenzylguanidine↗
PubMed1999

Histologic comparison of coronary and iliac atherectomy tissue from cases of in-stent restenosis.

Pathologically, restenotic lesions after stenting were investigated by use of atherectomized tissues of seven coronary and seven iliac arteries. The mean interval of the stent deployment to restenosis was 9.1 months for the coronary artery and 33.7 months for the iliac artery, indicating a 3.7-fold longer interval for the latter. This study does not include cases of acute thrombotic occlusion. The atherectomized tissue from restenotic coronary arteries showed abundant neointima with alpha-actin-positive and ultrastructually synthetic-type smooth muscle cells in a rich myxomatous extracellular matrix. In the iliac arteries, the predominant component of restenosis consisted of organized thrombi. The neointima of the iliac arteries was mature, and only a small amount of spindle cells were observed in the hyalinized matrix. The tissue that developed restenosis after stenting was different in the coronary and iliac arteries included in this series. This study on the atherectomized tissue suggests that even in the chronic stage, a major cause of in-stent restenosis among the larger caliber vessels such as the iliac artery is not neointima but stent thrombosis.

Aged↗
PubMed1999

Saline-jet aspiration thrombectomy catheter. Clinical results in patients with venous thrombosis.

PURPOSE: To evaluate hydraulic thrombectomy using a saline-jet aspiration thrombectomy catheter in the treatment of venous thrombosis. MATERIAL AND METHODS: Ten patients underwent 12 hydraulic thrombectomy procedures using 2.7 or 4.0 mm catheters. The site of the thrombus was either central, peripheral or in portal veins. The age of the thrombi was between 2 and 60 days (mean 19.7 days). The efficacy of hydraulic thrombectomy was evaluated based on the aspirated thrombus ratio (ATR), i.e. the volume of the thrombus aspirated divided by the volume of the thrombus before thrombectomy. ATR was estimated by comparing the angiograms of the lesion before and after thrombectomy. RESULTS: Soft thrombi were usually rapidly removed. ATR was >2/3 in 3, 2/3-1/3 in 2, 1/3-0 in 4, and 0 in 1 patient. The activation time of the injector was 23-224 s (mean 102 s) and the volume of aspirated blood was 30-680 ml (mean 250 ml). Compensatory infusion of saline was performed for blood loss, and 400 ml of packed red blood cells was transfused in 1 patient. No complications of the hydraulic thrombectomy were observed. Thrombolysis or additional treatment were performed in 9 patients. CONCLUSION: Hydraulic thrombectomy using this catheter can contribute to the treatment of venous thrombosis.

Equipment Design↗
PubMed1999

[MR angiography of steno-occlusive lesions of intracranial arteries: a comparative study between turbo MRA and conventional MRA].

PURPOSE: To compare the quality and diagnostic accuracy of images of intracranial steno-occlusive lesions obtained by conventional MRA and turbo MRA reconstructed using the zero-filled interpolation technique in the slice-select direction. MATERIALS AND METHODS: Eighteen patients with suspected steno-occlusive lesions of the intracranial arteries were studied with two types of three-dimensional time-of-flight angiography and conventional digital subtraction angiography. In total, 45 steno-occlusive lesions were quantitatively measured using calipers and correlated with DSA stenosis. A phantom that simulated vessels with stenosis was also imaged using the two types of MRA under the same conditions as those employed in the clinical study. RESULTS: Compared with conventional MRA, turbo MRA reduced the jaggedness of vessels and offered appearances more similar to those of DSA in the antero-posterior and lateral views. The severity of stenosis was classified into five grades based on the percentage of occlusion: not significant (0-24%), mild (25-49%), moderate (50-74%), severe (75-99%), and occlusive (100%). Neither turbo MRA nor conventional MRA showed any discrepancy from DSA above grade-1 stenosis. CONCLUSION: The advantage of turbo MRA is its ability to reduce the jaggedness of vessels on conventional MRA, and to simplify the recognition of vessel contours without prolonging acquisition time. Turbo MRA and conventional MRA have equally high diagnostic accuracy for steno-occlusive lesions.

Aged↗
PubMed1999

Intravascular ultrasound observations during iliac stent deployment.

BACKGROUND: To evaluate the role of intravascular ultrasound (IVUS) during iliac stent deployment, with comparison of four major types of iliac stents. METHODS: Thirty-eight iliac arteries of 37 patients were observed with intravascular ultrasound after implantation of various stents including Palmaz stents in 10, Memotherm stents in 11, Wallstent in 10, and Strecker stents in 7. Quantitative measurements on ultrasound included the ratio of the short-axial to the long-axial diameters of the stent (symmetry index), the ratio of stent cross-sectional area to that of the reference lumen (expansion index), and stent-to-wall apposition. RESULTS: Intravascular ultrasound revealed significant differences among four major types of iliac stent, in spite of satisfactory angiographic appearances in all patients. It demonstrated significant deformity of the Strecker stent (symmetry index of 0.76-0.09) compared with other stents. The Memotherm stent and the Palmaz stent were superior to other stents in terms of degree of expansion (mean expansion index of 0.87 and 0.82 respectively). Stent cross-sectional area greater than 80% of the reference lumen could be sufficient for iliac stent deployment. The Palmaz stent was superior to other stents in terms of stent-to-wall apposition. CONCLUSIONS: Intravascular ultrasound can provide precise and useful cross-sectional morphological and quantitative information in terms of stent configuration, degree of stent expansion, and stent-to-wall apposition.

Aged↗
PubMed1999

Sustained elevation of plasma brain natriuretic peptide levels associated with progressive ventricular remodelling after acute myocardial infarction.

Previous studies have shown that levels of plasma brain natriuretic peptide (BNP) increase in an early phase of acute myocardial infarction. However, the relations between plasma BNP levels and left ventricular remodelling, which occurs long after acute myocardial infarction, are not fully understood. Venous plasma BNP levels were measured 2, 7, 14, 30, 90 and 180 days after the onset of acute myocardial infarction in 21 patients. Left ventricular end-diastolic volume index (EDVI, ml/m2) in acute (5 days) and chronic (6 months) phases were assessed by electron-beam computed tomography using Simpson's method. The remodelling group (n=9) was defined by an increase in EDVI >/=5 ml/m2 relative to the baseline value. Plasma BNP levels on days 2, 7, 14, 30 and 90 were significantly higher in the remodelling group than in the non-remodelling group (n=12, P<0.05). Sustained elevation of plasma BNP levels was noted from day 2 (61+/-12 pmol/l) to day 90 (55+/-12 pmol/l) and significantly decreased on day 180 (24+/-3 pmol/l) in the remodelling group. In contrast, plasma BNP levels significantly decreased from day 2 (25+/-4 pmol/l) to day 90 (9+/-1 pmol/l) and reached a steady level thereafter in the non-remodelling group. Plasma BNP levels on day 7 correlated positively with an increase in EDVI (r=0.70, P<0.001) from the acute to chronic phase. More importantly, the sustained elevation of plasma BNP (percentage decrease smaller than 25%) from day 30 to day 90 identified patients in the remodelling group with a sensitivity of 100% and a specificity of 83%. In conclusion, not only the high levels of plasma BNP in an acute phase, but also the sustained elevation of plasma BNP in a chronic phase, may be associated with progressive ventricular remodelling occurring long after acute myocardial infarction.

Adult↗