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S Yoshida

Publications and source records attributed to S Yoshida.

At least 307 records · Page 17Linked to original sources
PubMed2000

DNA polymerases and Ki-67 nuclear antigen are induced in correlation with the resected mass of rat liver up to 90%.

BACKGROUND AND AIMS: We studied the regeneration potential by measuring induction of DNA polymerases in the remnant rat liver after a partial hepatectomy (PHx) that is maximal but compatible with survival. METHODS: The regenerating rat liver was obtained after the 90% PHx. The induction of activities of DNA polymerase alpha, delta, and epsilon were measured after partial purification. The Ki-67 nuclear antigen was also detected histochemically. These parameters were compared with those after both 30% and 70% PHx. RESULTS: The 90% hepatectomy resulted in the strong inductions of DNA polymerase alpha, delta, and epsilon, at 48 h after operation, in association with increases in wet weight and total DNA in the remnant liver. The enzyme induction was much higher after 90% PHx than after 30% and 70% hepatectomy, in correlation with the resection volume. At 48 h after 90% hepatectomy, the Ki-67 positive cells increased up to 47.2% of hepatocytes in the remnant liver. CONCLUSION: The higher induction of replication enzymes by 90% hepatectomy reflects more cells entering mitogenic cell cycle, which supports the fast regeneration of the remnant liver. The number of proliferating hepatocytes is stringently controlled by an unknown mechanism sensing the mass of resected liver parenchyma.

Animals↗
PubMed2000

Treatment of dark-grown Arabidopsis thaliana with a brassinosteroid-biosynthesis inhibitor, brassinazole, induces some characteristics of light-grown plants.

When a brassinosteroid biosynthesis inhibitor, brassinazole (Brz), was applied at concentrations ranging from 0.1 to 2 microM. Arabidopsis thaliana (L.) Heynh seedlings grown in the dark exhibited morphological features of light-grown plants, i.e. short hypocotyls, expanded cotyledons, and true leaves, in a dose-dependent manner. Control (non Brz-treated) seedlings grown in the dark for 40 d did not develop leaf primordia. However, treatment with the lowest concentration of Brz induced the development of leaf buds, although it hardly induced any short hypocotyls, and treatment with the highest concentration of Brz induced both short hypocotyls and leaves. Labeling experiments with the thymidine analogue 5-bromo-2'-deoxyuridine revealed that amplification of cell nuclei and organellar nucleoids is activated in the shoot apical meristems of dark-grown Brz-treated seedlings. These results suggest that Brz-treatment induces development of true leaves. Furthermore, condensation and scattering of plastid nucleoids, which is known to occur during the differentiation of etioplasts into chloroplasts, was observed in the plastids of dark-grown Brz-treated cotyledons. In addition, high levels of ribulose-1,5-bisphosphate carboxylase-oxygenase proteins accumulated in the plastids of the cotyledons. Electron microscopy showed that the plastids were etioplasts with a prolamellar body and few thylakoid membranes. These results suggest that Brz treatment in the dark induces the initial steps of plastid differentiation, which occur prior to the development of thylakoid membranes. This is a novel presumed function of brassinosteroids. These cytological changes seen in Brz-treated Arabidopsis were exactly the same as those seen in a brassinosteroid-biosynthesis-deficient mutant, det2, supporting the hypothesis that Brz has no side-effects except inhibiting brassinosteroid biosynthesis, and should prove a useful tool in clarifying the role of brassinosteroids.

Arabidopsis↗
PubMed2000

Characterization of staurosporine-sensitive mutants of Saccharomyces cerevisiae: vacuolar functions affect staurosporine sensitivity.

Mutations at several loci affect the sensitivity of the yeast Saccharomyces cerevisiae to staurosporine. We report here the characterization of novel staurosporine- and temperature-sensitive mutants (stt). Cloning and integration mapping showed that the genes STT2/ STT6, STT5, STT7, STT8 and STT9 are allelic to VPS18, ERG10, GPI1, VPS34 and VPS11, respectively. The products of ERG10 and GPI1, respectively, catalyze mevalonate and glycosyl phosphatidylinositol anchor synthesis, while VPS18 and VPS11 genes belong to the class C VPS (Vacuolar Protein Sorting) genes, and the VPS34 gene is classified as a class D VPS. Therefore, staurosporine sensitivity is affected by ergosterol and glycolipid biosynthesis and by vacuolar functions. We found that other vps mutants belonging to classes C and D exhibit staurosporine sensitivity, and that they show calcium sensitivity and fail to grow on glycerol as the sole carbon source; both of the last two characteristics are shared by vacuolar H+-ATPase mutants (vma). As vma mutants were also found to show staurosporine-sensitive growth, staurosporine sensitivity is likely to be affected by acidification of the vacuole. Moreover, wild type yeast cells are more sensitive to staurosporine in alkaline media than in acidic media, suggesting that staurosporine is exported from the cytosol by H+/drug antiporters. Pleiotropic drug resistance (PDR) genes also provide some resistance to staurosporine, because deltapdr5, deltasnq2 and deltayor1 strains are more sensitive to staurosporine than the wild-type strain. This suggests that staurosporine is also exported by the ATP-binding cassette (ABC) transporters on the plasma membrane. vma mutants and vps mutants of classes C and D vps are sensitive to hygromycin B and vanadate, while ABC transporter-depleted mutants do not show such sensitivity, indicating that two systems differ in their ability to protect the cell against different types of drug.

ATP-Binding Cassette Transporters↗
PubMed2000

Effect of surgical stress on endogenous morphine and cytokine levels in the plasma after laparoscopoic or open cholecystectomy.

BACKGROUND: Endogenous morphine in the brain leads to various biological responses after surgery. The aim of this study was to determine whether morphine levels in the plasma would be enhanced by open laparotomy rather than by laparoscopic procedures. METHODS: We compared 19 patients who underwent laparoscopic cholecystectomy with five patients who underwent resection of the gallbladder by open laparotomy. Morphine levels in the plasma were measured by an electrochemical detection system. RESULTS: Postoperative endogenous morphine levels were higher with open laparotomy than with the laparoscopic technique (three h after surgery: open, 200 +/- 52.6 fmol/ml vs laparoscopy, 17.6 +/- 3.7, p < 0.01). This morphine elevation accounted for higher levels of cytokine, greater pain scores, and longer duration of fasting in open laparotomized patients than in laparoscopic cholecystectomy patients. Stress hormone levels in the plasma were also higher with open laparotomy than with laparoscopy. CONCLUSION: Morphine synthesis was enhanced by open laparotomy, resulting in greater biological response postoperatively than that seen with laparoscopic cholecystectomy.

Adrenocorticotropic Hormone↗
PubMed2000

Morbidity and mortality after 94 extrapleural pneumonectomies for empyema.

BACKGROUND: Extrapleural pneumonectomy is still indicated in some patients with empyema. We examined morbidity and mortality after this high-risk operation. METHODS: Between 1979 and 1998, 94 (92 chronic, 2 postsurgical) patients with empyema underwent extrapleural pneumonectomy. There were 79 men and 15 women (mean age, 59 years). Eighty-eight patients had a history of tuberculosis, and 53 had undergone a therapeutic pneumothorax. The right side was operated on in 50 patients and left in 44. RESULTS: Operative mortality was 8.5%. Fifteen major complications (1 esophageal perforation, 9 empyemas, and 5 bronchopleural fistulas) occurred in 13 patients. Eight patients required reexploration for hemorrhage. Reexploration was a risk factor for empyema. Bronchopleural fistulas occurred only on the right side. Eighty-nine percent of the 86 operative survivors were free of empyemas at 5 years. Overall 5-year survival was 83%, and survival was better in patients without than in those with empyema. CONCLUSIONS: Extrapleural pneumonectomy for empyema has acceptable morbidity and mortality. Postoperative empyema affects prognosis. Covering a bronchial stump with muscle is recommended, especially when the operation is performed on the right side.

Adult↗
PubMed2000

Surgical management of unstable patients in the evolving phase of acute myocardial infarction.

BACKGROUND: Acute myocardial infarction (AMI) can be treated with thrombolysis or coronary catheter intervention; surgical treatment--coronary artery bypass grafting (CABG)--is reserved for the patients in whom other procedures have failed. We performed CABG in 47 patients during the evolving phase of AMI, and analyzed their short-term and long-term results. METHODS: Preoperative, intraoperative, and postoperative data were analyzed in patients who underwent emergency CABGs for AMI between January 1, 1992, and July 31, 1998. CABGs performed more than 7 days after AMI were excluded from this study. RESULTS: The subjects were 47 patients (33 males and 14 females) with AMI who were treated by emergency CABG. Intraaortic balloon pumping was used in 44 cases and percutaneous circulatory pulmonary support was used in 3 cases. The mean interval between the onset of AMI and surgery was 27.4 +/- 27.9 hours. The mean number of bypass grafts was 3.0 +/- 1.1, and at least 1 arterial conduit was used in 45 cases (95.7%). Aortic clamp time, pump time, and operative time were 64.7 +/- 31.7, 117.3 +/- 55.2, and 313.2 +/- 84.8 minutes, respectively. IABP or percutaneous cardiopulmonary support were removed in the intensive care unit (ICU) 30.0 +/- 28.9 hours after CABG. The patients were extubated 41.4 +/- 40.5 hours after surgery, remained in ICU for 4.7 +/- 2.7 days, and were discharged from the hospital after 27.0 +/- 22.5 days. Three patients died from multiorgan failure related to postoperative sepsis, and 8 cases of major complications were observed. The actuarial 5-year survival rate of the patients treated with CABG was 83.0%. CONCLUSIONS: Surgical treatment in the unstable patients after AMI can be performed with acceptable risk. Arterial revascularization may contribute to improvement in long-term results.

Aged↗
PubMed2000

Semantic priming in patients with Alzheimer and semantic dementia.

Semantic priming for pairs of words having semantic relation (members of the same category) but not associative relation was tested in four patients with mild Alzheimer-type dementia (AD), three patients with semantic dementia (SD) and three normal controls. Priming effects were exhibited by all the AD patients and normal controls but by none of the SD patients. The facilitation did not differ depending on whether words were written in kanji or kana. The nature of semantic deficits in AD and SD is discussed.

Aged↗
PubMed2000

Prenatal detection of a high-risk group for intrauterine growth restriction based on sonographic fetal biometry.

OBJECTIVE: This study was performed to evaluate the significance of sonographic fetal biometry in predicting low birth weight. METHOD: Five hundred and sixty-eight single-term pregnancies were analyzed. They were stratified into seven subgroups by birth weight deviation (BWD). Among the 568 pregnancies, 115 were revealed to be small-for-gestational-age (SGA) (birth weight less than mean -1.5 S. D.). When IUGR was suspected by routine sonographic fetal biometry, 'IUGR work-up' was carried out. The diagnostic performance of our screening method for the detection of SGA pregnancies in the general population was calculated. RESULT: The sensitivity, specificity, positive predictive value, negative predictive value and odds ratio of our screening method for the detection of SGA pregnancies in the general population were 73.0, 96.6, 83.2, 98.0% and 131.0, respectively. CONCLUSION: These data suggest that sonographic biometry is useful for the prenatal detection of high-risk cases of fetal growth restriction.

Biometry↗
PubMed2000

The configuration of methyl jasmonate affects paclitaxel and baccatin III production in Taxus cells.

All stereoisomers of methyl jasmonate (MJA) were prepared, and their effects on cell yield and promotion of paclitaxel (Taxol) and baccatin III production investigated in cell suspension cultures of Taxus media. (3R,7S)-MJA showed the strongest cell growth inhibition, followed by (3R,7R)-MJA. In contrast, (3S,7R)- and (3S,7S)-MJA had very low inhibitory effects, indicating that this inhibition depends largely on the (3R)-configuration. In terms of the promotion of paclitaxel and baccatin III production, (3R,7R)-MJA had the highest activity. Although it showed considerable activity at low concentration, at higher concentrations the activity was decreased due to strong inhibition of cell growth. Interestingly, paclitaxel and baccatin III contents increased even at a high (3S,7R)-MJA concentration, whereas the other isomers had the opposite effects. These findings are interpreted to suggest that the optimum configuration is (3R,7R), the (3R)-configuration not being indispensable, and that the (7R)-configuration is suitable for the promotion of paclitaxel and baccatin III production.

Acetates↗
PubMed2000

28-Norcastasterone is biosynthesized from castasterone.

Metabolic experiments with deuterium-labeled castasterone in seedlings of Arabidopsis thaliana, Oryza saliva and Lycopersicon esculentum, and cultured cells of Catharanthus roseus were performed, and the metabolites were analyzed by GC-MS. In all the plant species examined, [2H3]28-norcastasterone was identified as a metabolite of [26,28-2H6]castasterone, indicating that castasterone is the biosynthetic origin of 28-norcastasterone. Moreover, the natural occurrence of 28-norcastasterone and 28-nortyphasterol in seedlings of A. thaliana has been demonstrated. This is the first report of the natural occurrence of 28-nortyphasterol in plants.

Cells, Cultured↗
PubMed2000

Biosynthesis of brassinosteroids in cultured cells of Catharanthus roseus.

Precursor administration experiments with 2H-labeled 6-oxocampestanol, 6-deoxocastasterone and 6alpha-hydroxycastasterone in cultured cells of Catharanthus roseus were performed and the metabolites were analyzed by GC-MS. [2H6]Cathasterone was identified as a metabolite of [2H6]6-oxocampestanol, whereas [2H6]6alpha-hydroxycastasterone and [2H6]castasterone were identified as metabolites of [2H6]6-deoxocastasterone, and [2H6]castasterone was identified as a metabolite of [2H6]6alpha-hydroxycastasterone, indicating that 6-deoxocastasterone is converted to castasterone via 6alpha-hydroxycastasterone. In addition, 6-deoxocathasterone, a putative biosynthetic intermediate in the late C6-oxidation pathway, was identified as an endogenous brassinosteroid. These studies provide further evidence supporting our proposed biosynthetic pathways for brassinolide.

Cells, Cultured↗
PubMed2000

Synthesis of 6-oxy functionalized campest-4-en-3-ones: efficient hydroperoxidation at C-6 of campest-5-en-3-one with molecular oxygen and silica gel.

As a reference compound library for the investigation of biosynthesis of brassinosteroids, focused on a pathway from campesterol (1) to campestanol (2), 6-oxy functionalized campest-4-en-3-ones as well as campest-5-en-3-one (7) and campestane-3,6-dione were prepared from 1. Oxidation of 1 with pyridinium chlorochromate buffered by calcium carbonate gave 5-en-3-one (7) in 76% yield. Treatment of 7 with silica gel under an oxygen atmosphere in ethyl ether at room temperature produced efficient hydroperoxidation at the C-6 position to give 6alpha-hydroperoxycampest-4-en-3-one and 6beta-hydroperoxycampest-4-en-3-one in 34% and 49% yields, respectively. These compounds were converted to 6alpha-hydroxycampest-4-en-3-one and 6beta-hydroxycampest-4-en-3-one by reduction with triethyl phosphite. This provided the first example of the practical use of hydroperoxidation at C-6 of a Delta(5(6))-unsaturated 3-oxo-steroid with molecular oxygen and silica gel. On the other hand, oxidation of 1 with pyridinium chlorochromate in the absence of calcium carbonate gave campest-4-ene-3,6-dione in 64% yield. This compound was then converted in a highly stereoselective manner to campestane-3,6-dione with A/B trans ring junction by reduction with titanium (III) chloride in 85% yield.

Biochemistry↗
PubMed2000

Brain metastasis in patients with sarcoma: an analysis of histological subtypes, clinical characteristics, and outcomes.

BACKGROUND: The clinical characteristics of brain metastasis from sarcoma are not well known. We examined the incidence and the characteristics of brain metastasis in patients with sarcomas. METHODS: All sarcoma patients treated at our institution from 1975 to 1998 were reviewed for brain metastasis. Diagnosis of the primary tumor was confirmed histologically, and brain metastasis was confirmed using computed tomographic (CT) brain scan. RESULTS: Brain metastasis was found in 27 (5.6%) of 480 patients with systemic sarcoma (7.2% soft part sarcoma, 3.5% bone sarcoma, 15.1% distant metastasis). Of these 27 sarcoma patients with brain metastases, lung metastasis occurred in 16 patients (59.3%). Out of 10 patients surgically treated, 8 patients survived more than 16 months. Median survival period after craniotomy was 25.4 months. CONCLUSIONS: We recommend aggressive treatment for those patients with brain metastases whose performance scores are over 70.

Adolescent↗
PubMed2000

Characteristic features of malignant lymphoma with central nervous system involvement.

BACKGROUND: Cerebral lymphoma is becoming increasingly common. METHODS: We reviewed the records of all our patients with non-Hodgkin's lymphoma (NHL) seen from April 1987 to August 1996 in our institute. Our analysis of these patients with lymphomatous central nervous system (CNS) involvement documents the clinical features, histology, and prognostic factors in CNS lymphoma. RESULTS: A total of 351 cases of NHL were treated in our institute. CNS lymphoma was found in 58 of 351 (16.5%) patients in our series. Forty-nine of 58 (84.5%) patients with CNS involvement also had systemic disease. Primary CNS lymphomas were detected in nine patients. Leptomeningeal infiltration was seen in 31 of 58 patients, whereas intracerebral infiltration was detected in 28 patients. Initial symptoms of CNS involvement included severe headache, muscle weakness, and other neurological signs. Malignant cells were detected in 32 of 132 studies in the cerebrospinal fluid examination. In the nine patients with primary CNS lymphoma, the median survival time was 16.5 months (range, 4-28 months). The overall median survival of the 58 CNS lymphoma patients was only 13.4 months (range, 1 to 32 months). CONCLUSIONS: Because prophylactic treatment was only successful in systemically well-controlled patients, control of systemic lymphoma seems to be of great importance.

Adult↗
PubMed2000

Synaptic microenvironments--structural plasticity, adhesion molecules, proteases and their inhibitors.

Proteolytic regulation might be essential in neural plasticity in mature brain as well as the developing brain. An increasing number of studies support the idea that structural changes in the synapses are closely associated with synaptic plasticity. Proteases and their inhibitors in a synaptic microenvironment are important in the regulation of dynamic changes in the extracellular matrix components associated with synaptic plasticity. In the present article, the possible roles of neuronal proteases, protease inhibitors and extracellular macromolecules are reviewed.

Animals↗
PubMed2000

Differential suppression of liver-specific genes in regenerating rat liver induced by extended hepatectomy.

BACKGROUND/AIMS: The function of the remnant liver is critical to survival of patients following an extended hepatectomy. The aim of this study was to determine whether proliferating hepatocytes in the remnant liver preserve the expression of liver-specific genes. METHODS: Using regenerating rat livers after 30, 70, and 90% partial hepatectomy (PHx), Northern blot analyses were performed with probes for seven liver-specific genes, six growth-related genes, two housekeeping genes and two acute phase reactant protein genes. RESULTS: During the regeneration after 90% PHx, the transcription of liver-specific genes showed three chronological patterns: transcription of serum albumin and cytochrome P450 2B decreased rapidly and reached a nadir at 6 to 24 h after PHx; those of apolipoprotein A-1, phosphoenolpyruvate carboxykinase and ornithine transcarbamylase decreased gradually until 24 to 48 h; those of UDP-glucuronosyltransferase and hepatocyte nuclear factor 4 did not show any changes until 48 h after PHx. In contrast, expression levels of all the growth-related genes and of housekeeping genes increased rapidly after PHx. After 30 and 70% PHx, expression of these genes changed in a similar manner to the 90% PHx case but to a lower extent. CONCLUSIONS: Based upon the fractions of Ki-67 positive hepatocytes in remnant livers, we could estimate the degree of expression of each liver-specific gene in the proliferating hepatocytes. The serum albumin gene was completely suppressed, while that encoding UDP-glucuronosyltransferase was not affected. These results correlated well with the patterns of albumin and bilirubin in rat serum after PHx. Other liver-specific genes were moderately suppressed in proliferating hepatocytes. Thus, expression of liver-specific gene is differentially suppressed when hepatocytes enter a proliferation cycle. Those that are unaffected may be indispensable for maintaining the homeostasis of the living organism.

Animals↗