Search PubMed⌕ Search

Biomedical subjects

S Yamagata

Publications and source records attributed to S Yamagata.

At least 163 records · Page 9Linked to original sources
PubMed1985

Therapeutic effect of cryosurgery of murine osteosarcoma--influence on disease outcome and immune function.

Experiments comparing conventional operative treatment and cryosurgery of a murine osteosarcoma showed that local tumor destruction by freezing in situ was similar or superior to amputation concerning survival and formation of metastasis, depending on tumor stage. Limited local resection was less effective. Immune functions affected by cryosurgical tumor destruction included depression of natural killer cell activity and decrease of tumor-specific autologous IgG antibodies in the serum.

Animals↗
PubMed1985

[Phase II study of UFT in cancer of the uterine cervix].

UFT Phase II study was undertaken as a joint research project at 6 institutions on 36 patients with cancer of the uterine cervix. Results showed that, in the 25 of 36 cases in whom results and conclusions were feasible, there was an effectiveness of 16% (CR 3 cases, PR 1 case, NC 17 cases, PD 4 cases). Histologically, there was 25% effectiveness with large-cell, non-keratinizing, epidermoid carcinoma, against 16.7% with small-cell type. Considerable effect was noted as to metastasis effect in terms of location: Virchow 50%, and lungs 33.3%. CR effectiveness was noted in one case of local recurrence following irradiation. In 10 (37%) of the 27 evaluable cases some side effects were observed. Virtually all involved the digestive organs, and serious bone-marrow problems, hepatic or renal impairment were not evident. The findings suggested that UFT is an effective chemotherapeutic agent against carcinoma of the uterine cervix.

Adenocarcinoma↗
PubMed1985

[Phase II study on MCNU in patients with advanced or recurrent gastrointestinal cancer].

A phase II study on MCNU (Methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside) was performed in 33 patients with advanced or recurrent gastrointestinal cancer under the cooperation of eight institutions in Hiroshima Prefecture. MCNU was given by means of intravenous drip infusion and the 33 cases were divided into three groups according to the method of administration; (A) 50mg/m2 every 1 or 2 weeks, (B) 70mg/m2 every 2 weeks or (C) 90mg/m2 every 6-8 weeks. Among 28 evaluable cases, 1 complete response (CR) and 1 partial response (PR) were observed and these two cases were gastric cancer patients. Platelet nadir occurred at the 3rd or fifth week after MCNU administration, but the leukocyte count was not so decreased. Subjective side effects were nausea, general fatigue and vomiting, but these were observed to be only mild.

Antineoplastic Agents↗
PubMed1984

New small-caliber antithrombotic vascular prosthesis: experimental study.

Vascular prostheses with the inner diameter smaller than 1 mm were implanted to the common carotid artery of rats, and their patency was examined. Four types of tubes were prepared for this purpose in Experiment 1: polyethylene (PE), poly-(acrylic acid)-grafted polyethylene (PE-AA), polyacrylamide-grafted polyethylene (PE-AAm), and poly(vinyl alcohol) (PVA) tubes. Comparative studies made using nonsuture anastomosis revealed that the PE-AAm and PVA tubes were antithrombotic, although disconnection was noted at the anastomotic sites within 1 week and 1 month, respectively. Thereafter in Experiment 2, the PVA tubes were implanted to the common carotid artery of 20 rats using conventional anastomosis. Neither anticoagulants nor fibrinolytic agents were used in both series of experiments. Patency of the PVA tubes was 80% after 1 week and 70% after 1 month. In patent cases after 1 month, the luminal surfaces of the prostheses and the host arteries were examined using scanning electron microscopy. The lumen of the arteries and anastomotic sites was covered with endothelial cells, while the lumen of the PVA tubes was free from thrombi and there was no neointima formation. So far, there has been reported no manmade material that has completely antithrombotic property in vivo. However, our studies disclosed that PVA is antithrombotic and one of the most promising materials for the inner surface of small vascular prostheses.

Acrylic Resins↗
PubMed1984

FBJ virus-induced osteosarcoma contains type I, type I trimer, type III as well as type V collagens.

The FBJ osteosarcoma (a virus-induced osteosarcoma named after its discoverers, Finkel, Biskis, and Jinkins) contains an extensive extracellular matrix. Collagens were extracted by digestion with pepsin in dilute acetic acid from tumors grown in lathyritic mice and fractionated by differential salt precipitation, yielding five fractions. Fraction 1 (precipitated at acidic 0.7 M and neutral 2.0 M NaCl) gave rise mainly to alpha 1(III) chain on phosphocellulose column chromatography. The alpha 1(III) chain was identified by its typical behavior on interrupted electrophoresis and analysis of the CNBr-cleaved peptides. The alpha 1(III) chain of the FBJ tumor had a high content of hydroxylysine and neutral saccharide. Fraction 2 (precipitated at acidic 0.7 M and neutral 4.5 M NaCl) yielded alpha 1(I) and alpha 2(I) chains on the phosphocellulose column from which alpha 1(I) was eluted as a broad peak, conceivably reflecting a high content of hydroxylysine and neutral saccharide. Fraction 4 (precipitated at acidic 1.2 M and neutral 4.5 M NaCl) yielded type V collagen, which also featured an exceptionally high content of neutral saccharide (Yamagata, S., et al. (1982) Biochem. Biophys. Res. Commun. 105, 1208-1214). The proportions of type I, type I trimer, type III, and type V collagens extracted by pepsin digestion from FBJ tumor were calculated to be 33, 29, 26, and 12%, respectively. The FBJ tumor is free from invasion by blood vessels, shows no deposition of calcium, and thus has the appearance of cartilage. But type II collagen, a specific gene product of cartilage, could not be identified in any of the fractions analyzed. Contrary to its appearance, collagen type analyses indicate that FBJ osteosarcoma is literally induced from osteogenic cells.

Amino Acids↗
PubMed1984

O-Acetylhomoserine sulfhydrylase of the fission yeast Schizosaccharomyces pombe: partial purification, characterization, and its probable role in homocysteine biosynthesis.

A crude extract of Schizosaccharomyces pombe cells catalyzed sulfhydrylation of both O-acetyl-L-serine and O-acetyl-L-homoserine with H2S, but did not synthesize cystathionine from O-acetyl-L-homoserine and L-cysteine. The O-acetylhomoserine sulfhydrylase [EC 4.2.99.10] was very unstable; however, it could be stabilized by the addition of 25% (w/w) sucrose or glycerol. The optimal pH for activity was 8.0 and that for stability was 7.0. The enzyme was purified approximately 300-fold from an ammonium sulfate-precipitated fraction. L-Methionine was the most effective inhibitor among the amino acids examined. It inhibited the enzyme competitively with respect to OAH with a Ki value of 2.6 mM. Sulfhydrylase activity was inhibited to various extents by some carbonyl reagents, but sulfhydryl reagents such as p-chloromercuribenzoic acid, 5,5'-dithio-bis(2-nitrobenzoic acid), and monoiodoacetic acid had no inhibitory effect. The enzyme also reacted with O-succinylhomoserine and L-homoserine to synthesize homocysteine directly, but could not utilize cysteine as a co-substrate in place of H2S. In the sulfhydrylation reactions, Km values for the substrates ranged from 10.4-12.5 mM. The enzyme was resolved to the apoenzyme by incubation with phenylhydrazine and reactivated by the addition of pyridoxal 5'-phosphate, whose Km value was 0.083 microM. The molecular weight of the enzyme was estimated to be approximately 186,000 by gel filtration and 170,000 by ultracentrifugation in sucrose density gradients. The isolectric point of the protein was pH 4.1. The characteristics of this enzyme are compared with those of physiologically functional sulfhydrylases reported for other organisms, and the possibility of the enzyme functioning as a homocysteine synthase is discussed.

Amino Acids, Sulfur↗
PubMed1983

Time limits of reversible cortical ischemia.

The duration and degree of reversible cortical ischemia was evaluated by monitoring the direct cortical response (DCR) and cortical blood flow as determined by a thermal diffusion flow probe (CBFp) in a small segment of cortex. Global ischemia was induced in 90 lightly anesthetized cats during recording. The thresholds for attenuation and abolition of the DCR were 23.7 +/- 6.9 (SD) and 8.7 +/- 3.4 ml/100 g/minute, respectively. With the abrupt drop of CBFp to 5 ml/100 g/minute or below, the DCR was obliterated in 2 to 6 minutes. Recovery of the DCR was likely to occur if it had been absent for only 10 minutes, but after 40 minutes without a DCR no animal recovered DCR, even though the animals were monitored for 6 hours. Correlation of CBFp with time of ischemia was done by analyzing the CBFp curve minute by minute and computing the mean CBFp during the ischemic insult. This was then compared to recovery of DCR. By plotting time (T) in minutes, CBFp in ml/100 g/minute, and recovery of DCR, T was identified for levels of CBFp when DCR would be unlikely to recover. The time limits of cortical ischemia are described for blood flows from 0 to 20 ml/100 g/minute. The physiological recovery of the cerebral cortex from ischemia is a function of the depth and duration of the ischemic episode.

Animals↗
PubMed1983

Therapeutic effects of cetraxate against acute gastritis and acute aggravation of chronic gastritis. Endoscopic investigation by the double-blind method.

To determine the efficacy of cetraxate against acute gastritis and acute aggravation of chronic gastritis, a comparison was made with aldioxa as the standard drug by the double-blind method based mainly on observations by gastroscopy. There were four types of gastroscopic findings used: hemorrhage, erosion, redness and edema. Observations were performed whenever possible before and 1, 2 and 4 weeks after administration, and the cure and improvement rates were investigated. The cure rates for each finding except edema after 1 and 2 weeks were better (in the order of redness, erosion and hemorrhages) in the cetraxate group than in the aldioxa group, and there was a significant difference for redness in the 1st week (p less than 0.05). The no change and aggravating rates were also lower for redness in the 1st week (p less than 0.05) and edema in the 1st week (p less than 0.10) in the cetraxate group than in the aldioxa group. There were almost no differences in the effects of both drugs on subjective symptoms. The safety based on type and incidence of side effects was considered to be high for both drugs. From these results, it appeared that cetraxate is effective against acute gastritis and acute aggravation of chronic gastritis.

Acute Disease↗
PubMed1983

[Autopsy case of pancreatic carcinoma associated with B-cell derived lymphoma].

An autopsy case a 75-year-old man, with papillary adenocarcinoma of the pancreas associated with wide-spread metastasis from a malignant lymphoma is reported. We discuss the markedly lower incidence of pancreatic cancer in syncronal association with lymphoma. We applied an immunoperoxidase method (PAP) in the diffuse large-cell lymphoma to determine the immunological phenotype and found mu heavy chains and lambda light chains in the lymphoma cells. This suggests that the tumor cells were derived from B-lymphocytes.

Adenocarcinoma, Papillary↗