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S Gotoh

Publications and source records attributed to S Gotoh.

At least 37 records · Page 2Linked to original sources
PubMed1999

cDNA sequence of bovine thioredoxin.

In this paper, we report the cDNA sequence of bovine thioredoxin. We determined the full-length cDNA sequence of bovine thioredoxin by RT-PCR, 5'-RACE and 3'-RACE methods. Currently, the thioredoxin cDNA sequences of only five mammalian species (human, macaca, mouse, ovine and rat) are registered in the GenBank database. We performed sequence comparisons on the total cDNA sequence and the coding region, and produced a multialignment between the amino acid sequences of bovine and other mammalian thioredoxins. The amino acid sequences of thioredoxins are highly conserved among mammalian species, for example, only one difference exists between the amino acid sequences of bovine and ovine thioredoxin.

Animals↗
PubMed1999

cDNA sequence of bovine thioredoxin.

In this paper, we report the cDNA sequence of bovine thioredoxin. We determined the full-length cDNA sequence of bovine thioredoxin by RT-PCR, 5'-RACE and 3'-RACE methods. Currently, the thioredoxin cDNA sequences of only five mammalian species (human, macaca, mouse, ovine and rat) are registered in the GenBank database. We performed sequence comparisons on the total cDNA sequence and the coding region, and produced a multialignment between the amino acid sequences of bovine and other mammalian thioredoxins. The amino acid sequences of thioredoxins are highly conserved among mammalian species, for example, only one difference exists between the amino acid sequences of bovine and ovine thioredoxin.

Amino Acid Sequence↗
PubMed1999

[A simple method for regional cerebral blood flow measurement by one-point arterial blood sampling and 123I-IMP microsphere model (Part 2): A study of time correction of one-point blood sample count].

In our previous paper regarding determination of the regional cerebral blood flow (rCBF) using the 123I-IMP microsphere model, we reported that the accuracy of determination of the integrated value of the input function from one-point arterial blood sampling can be increased by performing correction using the 5 min: 29 min ratio for the whole-brain count. However, failure to carry out the arterial blood collection at exactly 5 minutes after 123I-IMP injection causes errors with this method, and there is thus a time limitation. We have now revised our method so that the one-point arterial blood sampling can be performed at any time during the interval between 5 minutes and 20 minutes after 123I-IMP injection, with addition of a correction step for the sampling time. This revised method permits more accurate estimation of the integral of the input functions. This method was then applied to 174 experimental subjects: one-point blood samples collected at random times between 5 and 20 minutes, and the estimated values for the continuous arterial octanol extraction count (COC) were determined. The mean error rate between the COC and the actual measured continuous arterial octanol extraction count (OC) was 3.6%, and the standard deviation was 12.7%. Accordingly, in 70% of the cases, the rCBF was able to be estimated within an error rate of 13%, while estimation was possible in 95% of the cases within an error rate of 25%. This improved method is a simple technique for determination of the rCBF by 123I-IMP microsphere model and one-point arterial blood sampling which no longer shows a time limitation and does not require any octanol extraction step.

Adult↗
PubMed1998

Prompt activation of telomerase by chemical carcinogens in rats detected with a modified TRAP assay.

The maintenance of telomere length is crucial for survival of cells. Telomerase is an RNA-containing reverse transcriptase, which is responsible for elongation of shortened telomeres. Telomerase reactivation has been suggested to be involved in malignant progressions. To study on the involvement of telomerase activation in in vivo carcinogenesis, we first modified the original TRAP assay by changing the primer designs and the labeling method of PCR products to an end-labeling method. Second, we investigated the activation of telomerase in different organs after treatments of rats with various chemical carcinogens. Very early after the beginning of the treatment, telomerase activity in the liver, kidney, and lung was increased. In most cases, telomerase activation occurred in the primary or favorite target organs. The present results suggest that telomerase activation occurs promptly when animals are exposed to chemical carcinogens, which may contribute to in vivo chemical carcinogenesis.

Animals↗
PubMed1998

Concentration-dependent differential effects of N-acetyl-L-cysteine on the expression of HSP70 and metallothionein genes induced by cadmium in human amniotic cells.

Cadmium induces the expression of the 70 kDa heat shock protein (HSP70) and metallothionein (MT), both of which are considered to be associated with intracellular glutathione (GSH) metabolism in the cellular protection mechanism against cadmium-induced cellular injury. We determined the effects of N-acetyl-L-cysteine (NAC), which increases the intracellular GSH levels, on the induction of HSP70 and MT gene expression in a cultured cell line of human amniotic cells (WISH) exposed to CdCl2. The mRNA level of MT-II, a major isoform of MT genes, was more prominently increased than that of HSP70 when WISH cells were exposed to CdCl2 (5-15 microM, for 6 h). The treatment of WISH cells with 1.5 and 30 mM NAC for 2 h increased the intracellular GSH levels by 1.4- and 3.1-fold, respectively. Pretreatment of cells with 30 mM NAC significantly reduced both HSP70 and MT-II mRNA levels in the cells exposed to 50 microM CdCl2. This concentration of NAC also efficiently suppressed the cadmium-induced lethality. On the contrary, pretreatment with 1.5 mM NAC suppressed only the induction of HSP70 gene expression in the 50 microM CdCl2-treated cells, and did not inhibit the metal toxicity. However, this low concentration of NAC efficiently suppressed lipid peroxidation which was increased by 50 microM CdCl2. Furthermore, this low concentration of NAC also decreased the CdCl2-induced gene expression of HSP32 which represents a general response to oxidative stress. Taken together, NAC seems to have at least two concentration-dependent functions in WISH cells exposed to CdCl2; the low concentration of NAC can suppress the induction of HSP70 gene expression as well as the increase of lipid peroxidation via an antioxidant pathway, while the high concentration of NAC can suppress the induction of MT-II mRNA as well as cadmium-induced cell death. Our present data suggest that changes in intracellular redox status, as reflected by GSH concentration, have more important effects on the induction of HSP70 mRNA rather than that of MT-II mRNA in human amniotic cells exposed to cadmium.

Acetylcysteine↗
PubMed1998

Different responses other than the formation of DNA-adducts between the livers of carcinogen-resistant rats (DRH) and carcinogen-sensitive rats (Donryu) to 3'-methyl-4-dimethylaminoazobenzene administration.

Carcinogen-resistant inbred DRH rats developed from the Donryu strain showed a remarkably low incidence of liver tumors when they were fed diets containing hepatocarcinogens such as 3'-methyl-4-dimethylaminoazobenzene (3'-Me-DAB). In this work, we examined various characteristics of male DRH and Donryu rats during 3'-Me-DAB administration for 8 weeks. 32P-Postlabeling analysis showed that essentially similar levels of DNA-adducts were generated by the metabolites of 3'-Me-DAB in the livers of these two strains of rats at several time points. However, both GADD45 (growth arrest and DNA damage-inducible) and O6-methylguanine methyltransferase (putatively DNA damage-inducible) mRNA levels were increased significantly in Donryu rat livers, but were increased to a lesser extent in DRH rats. [3H]Thymidine incorporation into hepatic DNA began to increase around 10 to 20 days after the start of 3'-Me-DAB administration in Donryu rats probably due to DNA repair, while no significant change occurred in DRH rats under the same conditions. Furthermore, inductions of heme oxygenase (due to degradation of heme-proteins) and hepatocyte growth factor (HGF; cell death and regeneration of hepatocytes) mRNAs were greater in Donryu rat livers than those of DRH, suggesting that the former were more sensitive to cytotoxic effects of 3'-Me-DAB than the latter. Another remarkable difference observed between these two strains was the significant induction of cytochrome P-450 2E1 mRNA in Donryu rat livers; this may contribute to the generation of reactive oxygen intermediates. Finally, increases of glutathione S-transferase (P-form) and gamma-glutamyltranspeptidase mRNAs as marker enzymes of preneoplastic changes of hepatocytes were clearly seen only in Donryu rat livers at 6 to 8 weeks after the start of 3'-Me-DAB administration. These results indicate that the different susceptibility to hepatocarcinogenesis between these two strains of rats may arise from events other than the DNA adduct formation.

Animals↗
PubMed1998

[Measurement of regional cerebral blood flow using one-point arterial blood sampling and microsphere model with 123I-IMP: correction of one-point arterial sampling count by whole brain count ratio].

A correction method was proposed for measurement of the regional cerebral blood flow using one-point arterial blood sampling and a microsphere model with N-isopropyl-p-(123I)iodoamphetamine (123I-IMP). Instead of using continuous arterial blood sampling octanol-extracted counts, one-point arterial sampling whole blood counts corrected by the whole brain count ratio using 1-minute planar SPECT images were employed. The experimental subjects were 189 patients with cerebrovascular disorders. 123I-IMP, 222 MBq, was administered by intravenous infusion. Continuous arterial blood sampling was carried out for 5 minutes, and arterial blood was also sampled once at 5 minutes after 123I-IMP administration. Then the whole blood count of the one-point arterial sampling was compared with the octanol-extracted count of the continuous arterial sampling. A positive correlation was found between the two values (r = 0.87, p < 0.001). The correction method was carried out by calculation as follows. The ratio of the continuous sampling octanol-extracted count (OC) to the one-point sampling whole blood count (TC5) was compared with the whole brain count ratio (5:29 ratio, Cn) using 1-minute planar SPECT images, centering on 5 and 29 minutes after 123I-IMP administration. Correlation was found between the two values (r = 0.72, p < 0.001). The following relationship was shown from the correlation equation. OC/TC5 = 0.390969 x Cn-0.08924. Based on this correlation equation, we calculated the theoretical continuous arterial sampling octanol-extracted count (COC). COC = TC5 x (0.390969 x Cn-0.08924). There was good correlation between the value calculated with this equation and the actually measured value (r = 0.94, p < 0.001). The coefficient improved to r = 0.94 from the r = 0.87 obtained before using the 5:29 ratio for correction. For 23 of these 189 cases, another one-point arterial sampling was carried out at 6, 7, 8, 9 and 10 minutes after the administration of 123I-IMP. The correlation coefficient was also improved for these other point samplings when this correction method using the 5:29 ratio was applied. It was concluded that it is possible to obtain highly accurate input functions, i.e., calculated continuous arterial sampling octanol-extracted counts, using one-point arterial sampling whole blood counts by performing correction using the 5:29 ratio.

Blood↗
PubMed1997

Selective expression of HSP70-1 gene in the adrenal cortex but not in the medulla of thermally stressed rats.

The heat shock protein 70 (HSP70) gene expression in rat adrenal glands was investigated. In situ hybridization and Northern blotting revealed a marked increase of inducible HSP70 (HSP70-1) gene expression in the adrenal cortex, but not in the medulla, after whole body hyperthermia. In vivo footprinting assay of HSP70-1 promoter region suggested a possible involvement of other factor(s) in addition to the heat shock factor (HSF). We also detected significant increases of both ACTH and corticosterone in the plasma of the hyperthermic rats. These results suggested some physiological factors other than HSF may also participate in the tissue-specific induction of HSP70-1 gene in vivo.

Adrenal Cortex↗
PubMed1997

Increases of thrombomodulin activity and antigen level on human umbilical vein endothelial cells treated with asbestos and man-made mineral fibers.

The potential influences of crocidolite asbestos fibers and man made mineral fibers (potassium titanate whisker and magnesium sulfate whisker) on a procoagulant system of human umbilical vein-endothelial cells (HUVECs) were investigated by measuring the activity and antigen level of thrombomodulin (TM) on the cell surface. Statistically significant increases in both the TM activity and TM antigen level were observed on HUVECs treated with crocidolite asbestos fibers for 48 h and 72 h compared to untreated cells at low concentrations of the fibers which showed no sign of a cytotoxic effect on the cells. An extensive increase in both the TM activity and TM antigen level was also observed on HUVECs treated with potassium titanate whisker or magnesium sulfate whisker for 48 h and 72 h. A statistical analysis revealed that these fibers had almost the same effects on the increases in both TM activity and the TM antigen level of HUVECs treated with the fibers for 48 h and 72 h, but a treatment of magnesium sulfate whisker at more than 1.25 micrograms/ml for 24 h was slightly more effective in increasing TM activity on HUVECs compared to other fibers (p < 0.05). The [3H]leucine incorporation in HUVECs increased when the cells were treated with crocidolite asbestos or man-made mineral fibers (MMMFs), indicating that the increases in TM activity and the TM antigen level on HUVECs directly exposed to those fibers may not reflect the sole induction of anticoagulant activities, but the general cell damage induced by the fibers.

Air Pollutants, Occupational↗
PubMed1997

[A case of invasive bladder cancer with Pagetoid skin lesion of the vulva and anogenital Paget's disease].

A 70-year-old female was admitted to our hospital with a complaint of gross hematuria for two months. She had a 5 years history of eczematous vulvar skin eruption. With the diagnosis of T3N0M0 bladder cancer and anogenital Paget's disease, she underwent pelvic exenteration, vulvectomy and reconstruction of the vulva. Histopathological examinations and mucin stains revealed anogenital Paget's disease and invasive bladder cancer which extended to the clitoral skin and formed Pagetoid skin lesion. CEA and cyokeratin staining demonstrated identical expression pattern in bladder cancer cells and Paget's cells, which suggested both neoplastic cells originated from one progenitor cell.

Aged↗
PubMed1997

[A case of unilateral and synchronous occurrence of oncocytoma and renal cell carcinoma].

A 45-year-old female, who had undergone an operation for rectal cancer 4 years previously was admitted to our hospital because of a left renal mass found by follow-up ultrasonography. Ultrasonography revealed two high echoic tumors. Enhanced computerized tomography (CT) showed relatively low density tumors measuring 3.8 x 3.8 cm and 0.8 x 0.8 cm in the upper and lower pole, respectively. Renal angiography demonstrated a spoke-wheel appearance in the upper pole. Left radical nephrectomy was performed. Histopathological diagnosis of the tumor in the upper pole was oncocytoma and that in the lower pole was renal cell carcinoma.

Adenoma, Oxyphilic↗
PubMed1996

Conformation of cyclic and linear (1 --> 2)-beta-D-glucans in aqueous solution.

The conformations of cyclic (1 --> 2)-beta-D-glucan chains having degree of polymerization (dp) 17 to 24 were characterized by means of small-angle X-ray scattering and Monte Carlo simulation. The results indicate that cyclic (1 --> 2)-beta-D-glucan chains adopt the shape of a doughnut-like ring with a thickness of about 10 A for all the samples. The diameter of the annulus for the cyclic glucan having dp 21 is estimated to be only about 4-5 A. Two linear (1 --> 2)-beta-D-glucans possessing dp 19 and 21 prepared by acid hydrolysis of a cyclic glucan and subsequent fractionation showed different scattering profiles from those obtained for cyclic glucans having the corresponding dp. Although the Monte Carlo simulation does not completely reproduce the scattering profiles observed by small-angle X-ray scattering, linear (1 --> 2)-beta-D-glucans seem to possess a characteristic cylindrical shape with cross-sectional diameters of 11.8 and 13.2 A for linear glucans of dp 19 and 21, respectively.

Chromatography, High Pressure Liquid↗
PubMed1996

Linear systems analysis of activating processes of complement system as a defense mechanism.

The complement system is an important element of the host defense mechanism, although its kinetics and characteristics as a system are still unclear. We have investigated its temporal changes and system properties from the view point of system engineering. The temporal changes of sequential activating processes of the system were expressed by 26 non-linear differential equations using reported values of rate constants and serum concentration for each component. The intermediate products in the activating processes increased parabolically while the membrane attack component as the final product, increased linearly. The little change in inactive precursors afforded validity for system linearization. Linear systems analysis revealed that the system which was insensitive to the changes in rate constants was unstable. The system became stable when the feed-back input from the final product was set to operate on the first step of the activating processes. Seven uncontrollable variables were insensitive to changes in rate constants or system optimization that minimized the changes in concentrations of components in the complement system. The singular values of the complement system were reduced and the impulse responses of the system were improved when the system was optimized. When stronger minimization was imposed on the changes of concentration of the components in the complement system, the singular values were reduced more, the magnitude of the impulse responses was depressed further and the responses terminated earlier than those when the elements in the weighting matrix of concentration of the components were set to be unity. By this potent minimization, the influences of changes in rate constants on the singular values were diminished. The present theoretical analysis is presented to evaluate the ability of defense mechanism of complement system.

Animals↗
PubMed1996

Narrow photon beam dosimetry for linear accelerator radiosurgery.

The dosimetric characteristics of linear accelerator radiosurgery for 10-MV X-ray were measured. Measurement of the relative output factor and tissue maximum ratio with a microchamber produced results equivalent to those of measurement with X-ray film. The 80% isodose level width measured with the microchamber was significantly smaller than that measured with the X-ray film. For the measurement of relative output factor and tissue maximum ratio, a microchamber seems to be the more appropriate choice. X-Ray film was found to be suitable for beam profile measurement.

Phantoms, Imaging↗
PubMed1996

Effects of protease inhibitors on the absorption of phenol red and fluorescein isothiocyanate dextrans from the rat intestine.

The absorption enhancement effects of three types of protease inhibitors, aprotinin, bacitracin, and soybean trypsin inhibitor, on the small and large intestinal absorption of phenol red (PR) and fluorescein isothiocyanate dextrans (FDs) were examined in rats. Of these protease inhibitors, only bacitracin enhanced the absorption of PR and FDs from the rat small and large intestine. Thus, we suggest that bacitracin has not only a protease-inhibitory but also an absorption-enhancing capability. We examined the effects of various protease inhibitors on intestinal mucosal toxicity by measuring the leakage of Evans blue (EB) from the systemic circulation. Although there was a significant increase in the leakage of EB in the presence of bacitracin, it was considerably less than that in the case of polyoxyethylene 9-lauryl ether (BL-9), which was used as a positive control. Therefore, bacitracin may be a good model adjuvant for improving the intestinal absorption of poorly absorbable drugs because it did not cause serious intestinal mucosal damage, as seen in the case of BL-9.

Animals↗
PubMed1996

The measurement of caffeine concentration in scalp hair as an indicator of liver function.

Caffeine concentration in plasma and scalp hair has been determined for subjects consuming normal daily amounts of caffeine and the results used as an indicator of individual hepatic metabolic capacity. Daily exposure to caffeine was assessed in six healthy Japanese volunteers by direct HPLC measurement of the concentrations of caffeine in aliquots of all caffeine-containing beverages consumed by the subjects. The measurements were repeated on three different occasions for each subject and caffeine consumption (mean +/- s.d.) was calculated as 178.0 +/- 84.3 mg day-1 with an intra-individual variability of 23.8 +/- 6.3% as coefficient of variation. A survey of daily caffeine consumption in 121 adult Japanese by means of a questionnaire revealed a similar value (231.8 +/- 177.8 mg day-1). Caffeine concentration in the plasma sampled during an overnight caffeine-free interval was measured by HPLC and a comparison made between healthy subjects and patients with liver disease (0.71 +/- 0.32, 0.77 +/- 0.45 and 3.92 +/- 1.91 micrograms mL-1 for healthy volunteers (n = 6), patients with hepatitis (n = 11) and those with liver cirrhosis (n = 4), respectively). Strands of scalp hair were collected from six healthy subjects and six patients with liver cirrhosis. Caffeine in hair was identified and measured by gas chromatography-mass spectrometry after digestion of the hair matrix with protease and extraction of the caffeine with chloroform. Caffeine concentration in hair collected from patients with liver cirrhosis (26.5 +/- 5.04 ng mg-1 hair) was significantly higher than that in hair sampled from healthy subjects (7.21 +/- 3.11 ng mg-1). These findings suggest that the determination of caffeine concentration in the plasma and hair of subjects consuming normal daily amounts of caffeine-containing beverages provides a practical assessment of individual liver metabolic capacity.

Adult↗