Biomedical subjects

Shigeru Suzuki

Publications and source records attributed to Shigeru Suzuki.

33 records · Page 2Linked to original sources

PubMed2004

Hydrogen-deuterium exchange effects on beta-endorphin release from AtT20 murine pituitary tumor cells.

Abundant evidences demonstrate that deuterium oxide (D2O) modulates various secretory activities, but specific mechanisms remain unclear. Using AtT20 cells, we examined effects of D2O on physiological processes underlying beta-endorphin release. Immunofluorescent confocal microscopy demonstrated that 90% D2O buffer increased the amount of actin filament in cell somas and decreased it in cell processes, whereas beta-tubulin was not affected. Ca2+ imaging demonstrated that high-K+-induced Ca2+ influx was not affected during D2O treatment, but was completely inhibited upon D2O washout. The H2O/D2O replacement in internal solutions of patch electrodes reduced Ca2+ currents evoked by depolarizing voltage steps, whereas additional extracellular H2O/D2O replacement recovered the currents, suggesting that D2O gradient across plasma membrane is critical for Ca2+ channel kinetics. Radioimmunoassay of high-K+-induced beta-endorphin release demonstrated an increase during D2O treatment and a decrease upon D(2)O washout. These results demonstrate that the H2O-to-D2O-induced increase in beta-endorphin release corresponded with the redistribution of actin, and the D2O-to-H2O-induced decrease in beta-endorphin release corresponded with the inhibition of voltage-sensitive Ca2+ channels. The computer modeling suggests that the differences in the zero-point vibrational energy between protonated and deuterated amino acids produce an asymmetric distribution of these amino acids upon D2O washout and this causes the dysfunction of Ca2+ channels.

Actin Cytoskeleton↗

PubMed2004

Measurement of vascular diameter in vitro by automated software for CT angiography: effects of inner diameter, density of contrast medium, and convolution kernel.

OBJECTIVE: This investigation was performed to evaluate the accuracy of diameter measurement of vessels in vitro by automated software for CT angiography. MATERIALS AND METHODS: Vascular models with three inner diameters ( approximately 3, 4, and 6 mm) filled with contrast medium of three different densities ( approximately 460, 350, and 210 H) were scanned with helical CT. Five convolution kernels (soft, standard, detail, bone, and lung) were used. We evaluated the measurement error, defined as the difference between the diameter measured by the automated software and the true inner diameter of the vascular model. Statistical analysis involved three-way analysis of variance with repeated measures. RESULTS: Significant differences occurred in measurement error among the three vascular model inner diameters, among the three densities of intravascular contrast medium, and among the five convolution kernels (p < 0.01). In all the convolution kernels except lung, measurement errors progressively decreased with higher densities of intravascular contrast medium (p < 0.01). In vascular models filled with contrast medium of 350 H, measurement errors were significantly smaller in soft (mean +/- standard deviation [SD], 0.29 +/- 0.16 mm) and bone (0.23 +/- 0.05 mm) than in other convolution kernels (p < 0.01). CONCLUSION: The accuracy of diameter measurement was affected by the vascular model inner diameter, the density of contrast medium, and the convolution kernel. A higher density of intravascular contrast medium and selection of the proper convolution kernel will improve accuracy.

Angiography↗

PubMed2004

[Accuracy of diameter measurement in vitro using automated software for CT angiography: effect of convolution kernels].

The purpose of this study was to evaluate the accuracy of diameter measurement in vitro using automated software for CT angiography with five convolution kernels. Vascular models with three diameters (about 3, 5, and 8 mm) in three materials (water, oil, and air) were scanned by helical CT. Five convolution kernels were used for reconstruction. The accuracy of diameter measurement was affected by the diameter of the vascular model, material around the model, and convolution kernels. Selection of the proper convolution kernels may improve accuracy.

Angiography↗

PubMed2004

Determining sources of atmospheric polychlorinated biphenyls based on their fracturing concentrations and congener compositions.

Air samples collected at 23 sites in Kanagawa Prefecture, Japan in 1998 and 1999 were analyzed for PCBs by a high-resolution gas chromatograph/mass spectrometer. Concentrations of PCBs ranged from 10 to 3290 pg/m3N (geometric average, 120 pg/m3N) and were mostly less than 140 pg/m3N. The toxicity equivalency quantity (TEQ) values of co-planar PCBs ranges from not detected (ND) to 0.35 pg-TEQ/m3 N (mean value, 0.00063 pg-TEQ/m3 N). Cl3-PCBs comprised the highest level in many air samples. PCB congeners in the samples collected on three consecutive days did not vary significantly, suggesting that variation of PCBs concentrations is minimal among the samples collected at same sites. On the other hand, the pattern similarities of PCBs in the samples collected at various areas were not consistent. Contamination from commercial PCBs (Kaneclor) was observed in some samples with high PCBs concentrations. The compositions of PCB congeners in the samples collected at the sites near municipal waste incinerators were similar to those of PCB congeners in the samples collected at common environments in Japan, whereas they were completely different from those in the exhaust gases collected directly from municipal waste incinerators. Consequently, contribution of exhaust gases from incinerators to PCB concentrations and/or compositions of all air samples collected in the present study was not observed.

Air Pollutants↗

PubMed2003

L-[1-13C] phenylalanine breath test reflects phenylalanine hydroxylase activity of the whole liver.

OBJECT: The purpose of this study was to perform L-[1-13C] phenylalanine breath test (PBT), measure phenylalanine hydroxylase (PAH) activity in liver tissue biopsies from patients, analyze the relationship between PBT results and PAH activity, and determine the time point at which measurements best reflect PAH activity in liver tissue. METHODS: PBT was performed in 25 patients (10 with normal liver and 15 with liver cirrhosis). After administering 10 mg/kg L-[1-13C] phenylalanine, 300 ml of expired air was collected over 90 min at 15-min intervals. The rate of hepatic phenylalanine oxidation (%13C dose h(-1)) at each time point was calculated from the amount of 13CO(2) in the breath, assuming a CO(2) production rate of 300 mmol m(-2) body surface area per hour. Subsequently, we examined the relationship between the results of PBT and PAH activity. RESULTS: PAH activity of the whole liver was significantly decreased in hepatic cirrhosis patients (P < 0.05). The results of PBT %13C dose h(-1) correlated with the PAH activity/liver, with correlation coefficients at 30, 45, and 60 min of more than 0.7, and the maximum correlation was at 30 min (r = 0.821, P < 0.0001). %13C cumulative excretion correlated with the PAH activity/liver with correlation coefficients of more than 0.7 after 45 min. The maximum correlation was at 90 min (r = 0.770, P = 0.001). CONCLUSION: PBT values reflect PAH activity in the whole liver and, in particular, the % dose h(-1) at 30 min after oral administration highly correlates with PAH activity, providing an important indicator for monitoring changes in whole liver PAH activity.

Adult↗

PubMed2003

How fruit abundance affects the chimpanzee party size: a comparison between four study sites.

We examined the relationship between fruit abundance and chimpanzee (Pan troglodytes) party size by comparing data from four study sites: the Kalinzu Forest Reserve, Uganda, the Djinji Camp and Guga Camp in the Ndoki Forest, Congo, and Kahuzi-Biega National Park, Democratic Republic of Congo. Although the difference in the fruit abundance between the sites was responsible for the difference in the party size between the sites, the seasonal changes in fruit abundance did not explain the changes in the party size in each study site. Across the four study sites, there were significant correlations of the mean and minimum of monthly party size with the mean of monthly fruiting-tree density, and a significant correlation of the maximum of monthly party sizes with the minimum of monthly fruiting-tree density. We proposed a hypothesis that (1) the monthly fruit abundance affects the monthly party size in the sites where the fruit availability is as low as to limit the party size during a major part of a year, while (2) the party size does not increase with the increase in the monthly fruit abundance, but is affected by other social factors, in the sites where the minimum of monthly fruit abundance is high enough for chimpanzees to form parties of an adequate size.

Animals↗

PubMed2003

Patients with severe liver cirrhosis followed up by L-[1-(13)C] phenylalanine breath test.

Compared to healthy subjects, patients with severe liver cirrhosis (LC) are reported to show lower values in the L-[1-(13)C] phenylalanine breath test (PBT). We performed this test several times during the clinical course in two patients with severe liver cirrhosis (LC). Patient 1 was a 67-year-old woman with non-B, non-C LC and hepatocellular carcinoma (HCC) in the lateral hepatic segment. Because the patient wanted to receive nonsurgical treatment for HCC, intraarterial administration of zinostatin stimalamer was performed. The patient was hospitalized four times before her death from liver failure on December 20, 2000. During her clinical course, PBT was performed four times. Values for both the rate of hepatic phenylalanine oxidation (%(13)C dose h(-1)) and %(13)C cumulative excretion gradually decreased during her clinical course. Patient 2 was a 57-year-old man with hepatitis C virus (HCV)-positive LC. He was hospitalized seven times between December 1998 and his death on May 24, 2001. During his clinical course, PBT was performed four times. Values for both %(13)C dose h(-1) and %(13)C cumulative excretion decreased during his clinical course. We confirmed that PBT was useful for following the course of LC.

Aged↗

PubMed2003

L-[1-13C] phenylalanine breath test reflects histological changes in the liver.

OBJECTIVE: Compared with healthy individuals, patients with chronic liver disease reportedly have lower L-[1-13C] phenylalanine breath test (PBT) values. However, there is no report detailing the relationship between the results of PBT and pathological data in liver disease patients. This study was designed to investigate the degree of histological changes in the liver that induce PBT changes and the time of measurement that reflects the histological change. MATERIALS AND METHODS: PBT was performed in 47 patients (10 with a normal liver, and 37 with chronic hepatitis C). After administering 10 mg/kg L-[1-13C] phenylalanine, 300 mL of expired air was collected over 90 min at 15-min intervals. The rate of hepatic phenylalanine oxidation (%13C dose h(-1)) at each time point was calculated from the amount of 13CO(2) in the exhaled air, assuming a CO(2) production rate of 300 mmol m(-2) body surface area per hour. Subsequently, we examined the relationship between the results of PBT and METAVIR pathological scoring. RESULTS: The highest correlation coefficients between the fibrosis score and %13C dose h(-1) and between the fibrosis score and %13C cumulative excretion were obtained at 45 min (r = -0.779, R(2) = 0.607; P < 0.0001) and 75 min (r = -0.768, R(2) = 0.590; P < 0.0001), respectively. CONCLUSION: PBT is a useful adjunct for detecting histological changes in the liver. The %13C dose h(-1) value at 45 min and the %13C cumulative excretion value at 75 min of PBT are useful for detecting hepatic histological change.

Biomarkers↗

PubMed2003

Graphogenic epilepsy: a variant of language-induced epilepsy distinguished from reading- and praxis-induced epilepsy.

We report a case of graphogenic epilepsy as a variant of language-induced epilepsy. A 25-year-old, right-handed woman had noticed for the previous 10 years that writing almost always provoked jerks or a jerking sensation in her right hand. No other triggers, including facets of language function such as reading and speaking, elicited any epileptic seizures. Ictal EEG demonstrated an initial left central abnormality. In our report, we stress that graphogenic seizures as an expression of language-induced epilepsy should not be confused with those that are manifestations of juvenile myoclonic epilepsy, and that writing and reading trigger different facets of motor manifestations.

Adult↗

PubMed2003

[A cold agglutinin disease, difficult to distinguish from paroxysmal cold hemoglobinuria].

A 58-year-old male started passing dark brown colored urine in January 2002. An annual medical examination in the same month revealed a mild anemia and an increased serum LDH level. Because of the instability of the data of his peripheral red cell count and hemoglobin concentration as measuring with a blood cell auto-analyzer, and also the hemolytic findings in a test tube at room temperature (25 degrees C), he was referred to our hospital. Laboratory data revealed Hb 11.2 g/dl, reticulocytes 73.1% (233,000/microliter), indirect-bilirubin 2.8 mg/dl, LDH 757 U/l, and hemosiderinuria, suggesting some intravascular hemolysis. The cold agglutinin titer was > 1,024, direct and indirect Coombs tests were both positive, and the Donath-Landsteiner antibody (D-L antibody) was initially assessed as false positive because of a high titer of cold agglutinin. He was finally diagnosed as having a cold agglutinin disease (CAD) with anti-I autoantibody. Serologic tests for syphilis and mycoplasma, and various virus tests were all negatives. After avoiding cold exposure, his symptoms, including hemoglobinuria, disappeared. However, during 9 months follow-up, he still showed a high titer of cold agglutinin. This case suggests that CAD should be considered when peripheral blood cell count data are unstable as assessed by a blood cell auto-analyzer.

Agglutinins↗

PubMed2002

l-[1-(13)C]Alanine is a useful substance for the evaluation of liver function.

BACKGROUND: Using a rat model of hepatectomy, we investigated whether the severity of hepatopathy could be quantitatively measured from changes in expiratory (13)CO(2) levels after intravenous administration of l-[1-(13)C]alanine. MATERIALS AND METHODS: Under nembutal anesthesia, 20 mg/kg l-[1-(13)C]alanine was administered to rats via the femoral vein, and expiratory (13)CO(2) levels were measured for 15 min. Then, 30, 70, or 90% hepatectomy was performed. In the control group, simple laparotomy was performed. A breath test was conducted 20 min after laparotomy. We examined the correlation of total (13)CO(2) output (S) or single point (13)CO(2) level (SP) every 1 min for 15 min with liver weight/body weight (LW/BW) (%). RESULTS: In the control group, the breath test graph showed a specific peak level about 3 min after administration, but in all groups undergoing hepatectomy, it did not show any peak level during measurement. The correlation coefficient between S(12--15) after l-[1-(13)C]alanine administration and LW/BW was 0.902 (P < 0.0001). The correlation coefficient between SP(7) after l-[1-(13)C]alanine administration and LW/BW was highest, 0.908 (P < 0.0001). The severity of hepatopathy could also be evaluated, with significant differences in S(12-14) compared to control when the volume of resected liver was 30% or greater, but there was no significant difference between the groups undergoing 70 and 90% hepatectomy. However, the severity of hepatopathy could be evaluated, with significant differences in S(15) and SP(7) in all comparisons between groups. CONCLUSION: In the breath test with intravenously administered l-[1-(13)C]alanine, the severity of hepatopathy could be quantitatively evaluated in a short period by measuring S(15) and SP(7).

Alanine↗

PubMed2002

Ulcerative colitis associated with Takayasu's disease in two patients who received proctocolectomy.

Ulcerative colitis (UC) associated with Takayasu's disease (TD) is not common in Japan. Here, we report two patients with both diseases who received a total proctocolectomy. Patient 1, a 41-year-old woman with chronic continuous type UC, was first diagnosed with TD at the age of 10 years. Subsequently, she was diagnosed with UC and rectal cancer. HLA typing showed A2, A31(19), B52(5), and DR2(DRB1*1502). Coronary angiography showed 90% narrowing of the right coronary artery (RCA). After alleviating the RCA narrowing by percutaneous transluminal coronary angioplasty (PTCA), we performed a total proctocolectomy and ileostomy. Patient 2, a 20-year-old woman, was first diagnosed with TD at the age of 13 years. Severe symptoms, indicating fulminant UC, started 1 month prior to hospitalization. She was judged as needing surgery because the symptoms were not alleviated even with high doses of prednisolone. HLA typing showed A2, A31(19), B52, B61(40), DR2(DRB1*1502), and DR4 (DRB1*0405). Aortography showed a narrowing of the right renal artery; however, her renal function was normal. Based on these findings, we performed a three-stage operation for total proctocolectomy. Previously, we have reported that the DRB1*1502 and DRw11 genes were closely related to the intractability of UC. To date, we have not determined whether or how the DRB1*1502 gene might be related to TD. As the number of cases of UC associated with TD increases, it will be necessary to examine their DR2 subtypes.

Adult↗

PubMed2002

Death in epilepsy with special attention to suicide cases.

To examine clinical features of cases of death among epilepsy patients as a case-control study, with special attention to suicide, we analyzed the records of 43 deceased patients with well-classified epilepsy. The subjects were compared with 1,722 control patients who showed definite subtypes of epilepsy. As a result, among the major causes of death, 13 of the subjects suffered accidents (mostly drowning), ten experienced sudden unexpected death, seven had status epilepticus, and six committed suicide. There were no significant differences with regard to clinical variables except for psychotic episodes, which were more frequently encountered in subjects than in controls (chi(2)=6.771, P=0.009, Yates' modification). Statistically significant differences were found by epilepsy type as well (chi(2)=14.72, P=0.002), with temporal lobe epilepsy (TLE) proving to be most closely associated with death among the epilepsy patients. Further, suicide was only encountered in patients with TLE and the association was statistically significant (chi(2)=5.119, P=0.024). Half of those who committed suicide (n=3), did so by jumping in front of an oncoming train while in the midst of an episode of postictal psychosis. In conclusion, most cases of suicide in patients with epilepsy were found to be the result of an immediate causal relationship with ictal or interictal epileptic manifestations, rather than a result of augmentation of psychosocial stressors generated by a long-standing handicap derived from the severe illness.

Adult↗

PubMed2002

Pheochromocytoma presenting as an abdominal emergency: association with perforation of the colon.

A pheochromocytoma is a rare tumor derived from the adrenal medulla (or from chromaffin cells of sympathetic ganglia). Its symptoms derive mostly from the excessive release of catecholamines (adrenaline and noradrenaline). Hypertension is the most recognized feature of this disease, but gastrointestinal manifestations can on rare occasions be just as serious and life threatening. This report describes a rare case of a 70-year-old woman with pheochromocytoma who developed an acute abdominal emergency with shock and panperitonitis as a result of perforation of the descending colon which was effectively treated by surgical removal of the tumor and the perforated colon. There have been 2 such cases in the English literature in whom a pheochromocytoma was associated with perforation of the colon. Successful surgical removal of such a pheochromocytoma has been not reported previously. Our case demonstrates the importance of recognizing that a pheochromocytoma presents with a wide spectrum of manifestations, and rapid treatment brings improvement to the patient.

Abdomen, Acute↗

PubMedDate not supplied

Effect of superparamagnetic iron oxide-enhanced MRI of the liver with hepatocellular carcinoma and hyperplastic nodule.

PURPOSE: To evaluate the possibility of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) of the liver in predicting the histologic grade of hepatocellular carcinoma (HCC) and differentiating HCC from benign hyperplastic nodule (HPN). MATERIALS AND METHODS: Thirty patients with 31 histologically proved HCC and HPN underwent MRI (1.5 Tesla). HCCs were graded into well-differentiated HCC (HCCw; n = 10) and moderately to poorly differentiated HCC (HCCmp; n = 15). HPN was categorized into dysplastic nodule (DN; n = 1) and focal nodular hyperplasia (FNH; n = 6). T2-weighted fast spin echo images were obtained before and after administration of SPIO. Signal-to-noise ratios (SNR) of the lesion and surrounding liver parenchyma and contrast-to-noise ratios (CNR) were calculated pre- and postcontrast study. Relative enhancement ratios (RER), also known as signal intensity reduction ratios of the lesions, were also calculated. RESULTS: HCCw, HCCmp, DN, and FNH decreased in SNR after injection of SPIO. RER of HCCw was 19.5 +/- 13.3%, that of HCCmp was 6.8 +/- 5.8%, DN was 44.0%, and FNH was 42.9 +/- 4.8%. Significant statistical differences were seen between HCCw and HCCmp and HCC and HPN in RER. HCCw, HCCmp, and DN increased in CNR, and FNH decreased in CNR, but no lesion showed a statistically significant difference in CNR. CONCLUSION: SPIO-enhanced MR images may help to predict the histologic grade of HCC and distinguish HCC from HPN.

Adult↗