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T Okuyama

Publications and source records attributed to T Okuyama.

At least 19 recordsLinked to original sources
PubMed1992

Combined action of paraquat and superoxide on the peroxidation of detergent-dispersed linolenic acid.

We investigated the peroxidative effect of paraquat and active oxygens on detergent-dispersed linolenic acid in phosphate buffer (pH 7.5) from the malondialdehyde (MDA) level. Our complete system and further inclusion of catalase were effective in stimulating MDA formation. On the other hand, xanthine oxidase (XOD) or paraquat omission, superoxide dismutase (SOD) inclusion or anaerobic incubation inhibited the formation of MDA. Ferrous ion was weakly associated with phosphate of the buffer, forming a complex, and the release of ferrous ion from the complex intensified the MDA levels with the complete and catalase inclusion systems. The electron paramagnetic resonance (EPR) spectra using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) showed that superoxide, produced immediately after the addition of XOD, played a crucial role. We could obtain a DMPO-OOH signal at the starting stage whenever MDA stimulation was observed. The omission of paraquat, however, produced no increase in MDA level in spite of an appearance of DMPO-OOH signal, indicating that paraquat also plays an important role. On the other hand, Desferal, a ferric chelator, showed a concentration-dependent inhibition effect. There was an immediate strong intensity of DMPO-OOH and paraquat signals. We did not, however, observe MDA stimulation at 250 microM Desferal, which confirms that ferrous ion plays an essential role in the lipid peroxidation. These results indicate a combined action of paraquat (or its radical) and superoxide on the accessibility of ferrous ion, including its release from the complex with phosphate, which may be an endogenous chelator. The possibility of ternary complex participation is also discussed.

Cyclic N-Oxides↗
PubMed1992

Activation of protein kinase C by the 14-3-3 proteins homologous with Exo1 protein that stimulates calcium-dependent exocytosis.

The 14-3-3 proteins are a family of acidic proteins found mainly in the brain and are suggested to have a role in monoamine synthesis based on their ability to activate tyrosine and tryptophan hydroxylases in the presence of type II Ca2+/calmodulin-dependent protein kinase. Recently, however, it has been demonstrated that a member of the 14-3-3 family, termed Exo1, stimulates Ca(2+)-dependent exocytosis in permeabilized adrenal chromaffin cells, suggesting that this protein family may influence the protein kinase C-mediated control of Ca(2+)-dependent exocytosis. Here we show that the 14-3-3 proteins activate protein kinase C at about 2-fold more than the known level of the activated protein kinase, i.e. the activity of protein kinase C in the presence of Ca2+ and phospholipids. This raises the possibility that the cellular activity of protein kinase C is regulated by diverse members of the 14-3-3 family and that the reported ability of Exo1 to reactivate Ca(2+)-dependent exocytosis is based on its stimulatory effect on protein kinase C activity. The 14-3-3 family, therefore, appears to be a multifunctional regulator of cell signalling processes mediated by two types of Ca(2+)-dependent protein kinase, protein kinase C and type II calmodulin-dependent protein kinase.

14-3-3 Proteins↗
PubMed1992

Prophylactic lymph node dissection in patients with advanced gastric cancer promotes increased survival time.

BACKGROUND: There is no consensus of opinion regarding the efficacy of lymph node dissection. METHODS: Data were analyzed from 452 patients with advanced gastric cancer who underwent curative resection in the Department of Surgery II, Kyushu University Hospital, between 1970 and 1985, with special reference to the lymph node metastasis. RESULTS: Metastatic lesions were evident in the dissected lymph nodes of 300 of 452 (66.4%) patients. Survival time for patients without lymph node metastasis was longer than for those with it (P less than 0.01). In patients without lymph node metastasis, the tumor was smaller, serosal invasion was less prominent, tumor growth was less infiltrating, and the tumor stage was, therefore, less advanced. Lymphatic involvement was found in 38.9% of the patients with no evidence of lymph node metastasis. CONCLUSIONS: Because the postoperative mortality rate is low in patients with lymph node dissection, the authors advocate prophylactic lymph node dissection to prevent a recurrence.

Aged↗
PubMed1992

A rat cerebellar protein containing the cdc10/SWI6 motif.

Systematic analysis of soluble proteins in developing rat cerebellum by an automated two-dimensional liquid-chromatography system detected a number of proteins which increased transiently during the initial stage of postnatal development. One of the proteins, V-1, was isolated using a liquid-chromatography system, and its amino acid sequence was determined by analysis of the purified protein. The sequence showed that the V-1 protein consists of 117 amino acids with an acetylated N-terminus, and has 2.5 internal sequence repeats of 33 amino acids. Computer retrieval of the sequence indicated that the repeated sequences have a structural characteristics of the cdc10/SWI6 motif, which is found in a series of proteins, including those involved in cell-cycle control and cell-fate determination in yeast, Drosophila melanogaster and Caenorhabditis elegans. The structure of V-1, coupled with its controlled expression in early postnatal development, implies a potential role for V-1 in cerebellar morphogenesis.

Amino Acid Sequence↗
PubMed1992

Human carbonic anhydrase IV: cDNA cloning, sequence comparison, and expression in COS cell membranes.

We have isolated a full-length cDNA for human carbonic anhydrase IV (CA IV) from a lambda gt10 human kidney cDNA library. The 1105-base-pair (bp) cDNA contains a 47-bp 5' untranslated region, a 936-bp open reading frame, and a 122-bp 3' untranslated region. The deduced amino acid sequence is colinear with the N-terminal sequence and the sequence of several tryptic peptides of human lung CA IV. It includes an 18-amino acid signal sequence, a 260-amino acid region that shows 30-36% similarity with the 29-kDa cytoplasmic CAs (CA I, CA II, and CA III), and an additional 27-amino acid C-terminal sequence that ends in a 21-amino acid hydrophobic domain. Of the 17 "active site" residues that are highly conserved in other human CAs, 16 are also present in CA IV. Expression of the cDNA in COS cells produced a 35-kDa enzyme that was membrane associated, resistant to inactivation by SDS, contained no carbohydrate, and reacted on Western blots with antiserum to the 35-kDa CA IV from human lung. Treatment of membranes from transfected COS cells with phosphatidylinositol-specific phospholipase C released 20-30% of the expressed enzyme from membranes, indicating that at least 20-30% of the expressed enzyme was anchored to membranes by a glycosyl-phosphatidylinositol linkage.

Amino Acid Sequence↗
PubMed1992

Predictors of lymph node metastasis in early gastric cancer.

Data were analysed on 396 patients with early gastric cancer who underwent resection in this department; special reference was made to lymph node metastasis. Metastases were present in the dissected lymph nodes of 47 patients (11.9 per cent). The survival rate for patients with metastasis to lymph nodes was lower than for those without such metastasis (P less than 0.05). Lymph node metastasis was associated with larger tumour, a higher incidence of submucosal invasion, a higher rate of lymphatic vessel involvement, an advanced stage of disease and a non-curative resection rate of 6.4 per cent. Multivariate analysis showed that the independent risk factors for lymph node metastasis in patients with early gastric cancer were large tumour size, lymphatic vessel involvement and invasion into the submucosal layer. In patients with these risk factors, lymph node dissection and postoperative adjuvant therapy should be performed in an attempt to prevent recurrence in the form of lymph node metastasis.

Female↗
PubMed1992

Quality of life after gastrectomy in patients with carcinoma of the stomach.

One hundred and fifty patients without recurrence of disease after R2 gastrectomy for carcinoma of the stomach were interviewed to determine their quality of life after surgery. Patients ate less and weighed less but most appeared to be well adjusted and had an optimistic attitude regarding their physical state. There was no evidence of a diminished quality of life in those who had undergone distal partial gastrectomy. These patients had a higher overall food tolerance, body-weight and performance status compared with those treated by total gastrectomy. Considering the satisfactory outcome and the sustained quality of life, radical R2 gastrectomy may be the treatment of choice for carcinoma of the stomach.

Body Weight↗
PubMed1992

Prognostic factors for noncurative gastric cancer: univariate and multivariate analyses.

We performed univariate and multivariate analyses of possible prognostic factors related to postoperative clinical course of patients with advanced gastric cancer. Noncurative resection was done for 119 patients with hepatic metastasis, peritoneal seeding, extensive lymph node metastasis, or direct invasion to adjacent organs, either alone or in various combinations. In the univariate analysis, 6 of 17 items such as peritoneal seeding, lymphatic invasion, vascular invasion, mode of invasion, extent of lymphadenectomy, and width of serosal invasion significantly correlated to the prognosis. The multivariate analysis indicated that three inherent pathologic factors, mode of invasion, lymph node metastasis, and hepatic metastasis, and one treatment factor, extent of lymphadenectomy, were significant variables predictive of the prognosis and that the prognosis was expected to be very poor in cases of infiltrative type, nodal involvement to tertiary nodes, presence of hepatic metastasis, and lymphadenectomy less than R3. Prognosis in terms of the extent of lymphadenectomy shows that extensive lymphadenectomy (R3) proved to be significantly effective in prolonging survival time, even after noncurative gastrectomy. We recommend extensive lymphadenectomy to prolong survival time for such patients.

Adenocarcinoma↗
PubMed1992

Noncurative resection for advanced gastric cancer.

Between 1965 and 1985, 489 patients with advanced gastric cancer who were treated with gastric resection and in whom tumor cells remained after the operation were defined as cases of a "noncurative resection." The clinicopathological features and prognosis of these patients were examined and two groups were prepared: locally advanced cancer and cancer with a distant metastasis. In locally advanced cancer cases, tumor cells remained in the neighboring organs, lymph nodes, and/or resected margins; in those with distant metastasis, peritoneal dissemination and/or liver metastasis were present regardless of whether or not the metastasis was removed, with or without locally noncurative factors. Serosal invasion was prominent and high rates of lymph node metastasis and lymphatic involvement were evident in both groups. The survival rate for patients with locally advanced gastric cancer was better than that of patients with distant metastasis (P < 0.01). Survival time in patients with locally advanced cancer can be lengthened by resecting all of the primary tumor and as much of the metastatic lesions as possible, even if the surgical management is "noncurative." Aggressive postoperative chemotherapy for patients with distant metastasis from a gastric cancer is to be recommended.

Aged↗
PubMed1992

Analysis of prognostic factors in patients with hepatocellular carcinoma treated by transcatheter arterial embolization.

We studied 240 cases of unresected hepatocellular carcinoma (HCC) using Cox's proportional hazard model to elucidate which factors would be closely related with the survival period after treatment by transcatheter arterial embolization (TAE) in the presence or absence of iodized oil. The results were as follows. The cumulative survival values obtained after TAE were 67.5% for 1 year, 32.0% for 2 years, and 20.5% for 3 years. The most significant prognostic factor was the degree of extension of tumor embolus in the portal vein or its branch. The tumor extension and the tumor type were also important factors. Age, sex, and AFP, HBsAg, and HCV Ab values were not useful as prognostic factors. This study provides a rational background for the selection of treatment for HCC. Furthermore, knowledge of the prognostic factors is useful for the management of patients, particularly in maintaining their good quality of life.

Adult↗
PubMed1992

Cerebellar astrocytoma with repeated episodes of fourth ventricle isolation causing peritoneal shunt tube obstruction--case report.

A 9-year-old girl underwent total removal of a cerebellar astrocytoma complicated by hydrocephalus after postoperative meningitis, requiring a ventriculoperitoneal shunt. Five months later, headache, vomiting, and gait disturbance appeared and computed tomography detected enlarged fourth ventricle. A fourth ventriculoperitoneal shunt resulted in immediate relief of all symptoms. After 2 months, obstruction of the peritoneal tube required shunt reconstruction. This recurred three times in 8 months. At the last operation, tumor cells were detected in the cerebrospinal fluid and the substance clogging the tube. This suggested that the tumor had recurred and clogging by tumor cells had caused the repeated episodes of isolated fourth ventricle. Radiation therapy prevented further shunt obstruction and achieved remission of all signs and symptoms.

Astrocytoma↗
PubMed1992

[Two new steroidal saponins from Allium macrostemon].

Two new steroidal saponins, macrostemonoside A and D, were isolated from the bulbs of Allium macrostemon Bung (Chinese name as Xie bai), a Traditional Chinese Medicine used for the treatment of myocardial infarction. Their structures were established as tigogenin-3-O-beta-D-glucopyranosyl(1-->2) [beta-D-glucopyranosyl(1-->3)1]-beta-D-glucopyranosyl(1-->4)-beta-D- galactopyranoside (1) and tigogenin-3-O-beta-D-glucopyranosyl(1-->2)[beta-D-glucopyranosyl (1-->3)(6-O-acetyl-beta-D-glucopyranosyl)] (1-->4)-beta-D-galactopyranoside (2) by spectral and chemical evidences. 1 showed remarkable inhibitory effect on rabbit platelet aggregation induced by ADP in vitro (IC50 = 0.065 mmol).

Animals↗
PubMed1991

Automated two-dimensional liquid chromatographic system for mapping proteins in highly complex mixtures.

An automated two-dimensional liquid chromatographic system was developed for systematic protein separations which could serve for analytical mapping and preparative separations of proteins. The system applies the principles of the column-switching technique, and consists of two different columns connected in tandem through an electrical column switching valve, two pumping systems to operate each column independently and a system controller to perform sequential chromatography on the two columns. A protein mixture is applied to the first-dimensional anion-exchange column and is separated by stepwise elution with an increasing sodium chloride concentration. The eluent is introduced directly to the second-dimensional reversed-phase column, and is further separated by gradient elution with an increasing acetonitrile concentration. The two elution stages are synchronized by a computer program. By this system, very complex protein mixtures such as crude cerebellar extracts were resolved reproducibly into ca. 200 peaks within 12 h. The method can be used for the total analysis of proteins in various tissues and cells without complicated premanupulation of samples, and allows the simultaneous analysis of a protein isolated by chromatography. The isolated protein is most suitable for use in the strategy of protein and gene sequence analysis.

Animals↗
PubMed1991

Determination of glyphosate and its metabolite, (aminomethyl)phosphonic acid, in serum using capillary electrophoresis.

Capillary electrophoresis has been used to separate and quantitate glyphosate and its major metabolite, (aminomethyl)phosphonic acid (AMPA), in serum. The two compounds, after derivatization with p-toluenesulphonyl chloride, were clearly separated with 0.1 M boric acid-sodium hydroxide buffer (pH 9.6) containing 10% methanol. The separation was completed within 15 min at an applied potential of 30 kV. Calibration curves for the assay were linear over both the lower (0.5-10 micrograms/ml) and the higher (10-100 micrograms/ml) concentration ranges. The within-run and day-to-day coefficients of variation of peak area were 1.4-4.4 and 4.4-8.5%, respectively, for glyphosate and 1.8-2.9 and 1.8-2.9%, respectively, for AMPA. The within-run and day-to-day precisions of the migration time for both compounds were less than 1.8% and less than 2.5%, respectively. The detection limit of both derivatives was 0.1 microgram/ml in spiked sera, and the recoveries of glyphosate and AMPA were 87.9-88.8 and 78.4-86.9%, respectively. In this study, the reproducibility and the effect of pH changes on the electropherograms were especially examined.

Electrophoresis↗
PubMed1991

High-performance liquid chromatographic determination of glyphosate and (aminomethyl)phosphonic acid in human serum after conversion into p-toluenesulphonyl derivatives.

We have developed a simple, highly sensitive and fast assay method for determining glyphosate and its major metabolite, (aminomethyl)phosphonic acid (AMPA), in serum by high-performance liquid chromatography with ultraviolet detection. Both compounds were successfully extracted with an anion-exchange resin column and allowed to react with p-toluenesulphonyl chloride. The detection limits were 0.3 microgram/ml for glyphosate and 0.2 microgram/ml for AMPA. Recoveries of glyphosate and AMPA spiked to serum were ca. 75% and ca. 88%, respectively. We are convinced that this procedure, in practice, allows medical examiners to analyse both compounds in the serum of poisoned patients within a short time.

Chromatography, High Pressure Liquid↗