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Biomedical subjects

Y Hata

Publications and source records attributed to Y Hata.

At least 379 records · Page 21Linked to original sources
PubMed1989

Crystallization and preliminary X-ray studies of glutathione synthetase from Escherichia coli B.

The glutathione synthetase from Escherichia coli B has been crystallized from 27% saturated ammonium sulfate solution (pH 5.5). The crystals are hexagonal, space group P6(2)22 or P6(4)22. The cell dimensions are a = b = 88.0 A, c = 164.2 A, and gamma = 120 degrees. The enzyme is a tetramer (Mr = 143,000) with 222 symmetry, and the asymmetric unit contains one subunit molecule (Mr = 35,600). The crystals diffract to at least 2.5 A resolution.

Crystallization↗
PubMed1989

Platelet-derived growth factor stimulates synthesis of 1,2-diacylglycerol from monoacylglycerol in Balb/c 3T3 cells.

1,2-Diacylglycerol (1,2,-DAG) plays an important role in the protein kinase C-mediated signal-transduction system. Several reports have shown that 1,2-DAG is generated through various pathways other than classical phospholipid hydrolysis. We observed a rapid incorporation of [3H]myristate into 1,2-DAG in platelet-derived-growth-factor (PDGF)-treated Balb/c 3T3 cells. [14C]Palmitate was similarly incorporated into 1,2-DAG. The effect of PDGF, which was inhibited by cycloheximide, became maximal after 60 min treatment with PDGF, and disappeared 300 min after removal of PDGF. Treatment with triacylglycerol lipase revealed that labelled saturated fatty acid was incorporated into the sn-1 position. PDGF barely stimulated incorporation of [3H]glycerol or [14C]glucose into 1,2-DAG. Incorporation of [3H]myristate into 1,2-DAG preceded that into triacyglycerol and phospholipids. These results suggest that synthesis of 1,2-DAG from monoacylglycerol is enhanced in PDGF-treated cells. However, there is no significant difference in the activity of monoacylglycerol acyltransferase measured in vitro in quiescent and PDGF-treated cells. The reason for this discrepancy is discussed.

Acyltransferases↗
PubMed1989

Purification and characterization from bovine brain cytosol of two GTPase-activating proteins specific for smg p21, a GTP-binding protein having the same effector domain as c-ras p21s.

The smg-21 GTP-binding protein (smg p21) has the same effector domain as the ras proteins (ras p21s) and is identical with the proteins of the rap1A and Krev-1 genes. In this paper, two proteins stimulating the GTPase activity of smg p21 are partially purified from bovine brain cytosol. These proteins, designated as smg p21 GTPase-activating protein (GAP) 1 and 2, are separated from a c-ras p21 GAP described previously by column chromatographies. smg p21 GAP1 and -2 stimulate the GTPase activity of only smg p21 but not that of c-Ha-ras p21 or the rho and smg-25A GTP-binding proteins. smg p21 GAP1 or -2 does not stimulate the dissociation of guanosine 5'-3-O-(thio)triphosphate or GDP from smg p21. smg p21 GAP1 or -2 themselves do not have GTP/GDP binding or GTPase activity. The Mr values of smg p21 GAP1 and -2 are estimated to be 250-400 x 10(3) and 80-100 x 10(3) by gel filtration and sucrose density gradient ultracentrifugation, respectively. The activity of smg p21 GAP1 and -2 is killed by tryptic digestion or heat boiling. These results indicate that bovine brain contains two smg p21 GAPs in addition to c-ras p21 GAP.

Animals↗
PubMed1989

Surgical aspects of hepatic segmentation based on hepatic venographies.

Hepatic venographies were performed selectively in 42 patients with hepatocarcinoma. The findings were evaluated from anterior and lateral views. Thirty-nine right hepatic v. could be identified and the existence of one branch as the first ramification was found in 36 cases (92.3%). The first branches of the right hepatic v. could be classified into veins (V7) running from segment VII and those (V8) running from segment VIII. A V7 was identified in 26 cases (72.8%) and a V8 was identified in 10 cases (27.8%). The vena hepatica dorsalis (V8) running from segment VIII was recognised in 10 cases. The middle and left hepatic v. were identified in 31 cases and 33 cases respectively. Two main types of middle vein (one with no principal branching and the other with branching) were found in 11 cases (37.9%) and 12 cases (41.4%) respectively. The first branch of the middle hepatic v. (V8) running from segment VIII was identified in 10 cases (32.3%). These results indicate that anatomical consideration of the hepatic v. in each patient is necessary when performing hepatic resection.

Carcinoma, Hepatocellular↗
PubMed1989

Kidney-preserving radical tumor resection in advanced neuroblastoma.

The possibility of kidney-preserving radical tumor resection in advanced neuroblastoma was evaluated. Eighteen patients with stage III and IV adrenal neuroblastoma underwent delayed primary surgery after chemotherapy consisting of high doses of cyclophosphamide (1,250 mg/m2). Radical tumor resection with nephrectomy was performed in 13 patients (group A) and kidney-preserving radical tumor resection was performed in six patients (group B). Macroscopic findings were evaluated in all patients; angiographic and microscopic findings were evaluated in group A patients and tumor recurrence in group B patients. Macroscopically, the tumors were observed within the tumor capsule (C1) in five, outside the tumor capsule but not beyond the midline (C2) in seven, and beyond the midline (C3) in six. In group A, under microscopic examination, the tumor invasion into the renal parenchyma was observed in only three patients among C2 and C3 cases. Tumor vessels from the capsular and/or perforating arteries plus from the intrarenal arteries could be visualized in all patients, three of whom had tumor invasion into the renal parenchyma. In group B, no tumor recurrence around the kidney occurred, and two patients have survived for greater than 2 years. The kidney-preserving radical tumor resection is recommended in surgical treatment of advanced neuroblastoma following preoperative chemotherapy, and is predictable preoperatively by angiography.

Adrenal Gland Neoplasms↗
PubMed1989

Inhibitory effect of mature cartilage on perichondrial neochondrogenesis.

The perichondrium adhering to mature cartilage is not active, but that separated from cartilage is highly chondrogenic. Cartilage formation from isolated perichondrium does not last forever, and perichondrium soon becomes inactive. What activates or inactivates the perichondrium. The authors investigated the effect of mature cartilage on the cartilage formation from perichondrial graft material. The results showed that mature cartilage attached to the perichondrium inhibited neochondrogenesis. The phenomenon that cartilage--a product of chondrogenesis--inhibits neochondrogenesis of perichondrium can be called negative feedback.

Animals↗
PubMed1989

[Finite element stress analysis of ceramics crown on premolar. Relation between ceramics materials and abutment materials].

This investigation was carried out to evaluate the alteration of stress distribution on ceramics crowns by each combination of ceramics crown materials and abutment materials. Analyzing the stress distribution by the finite element methods, a two-dimensional model of jacket crown preparation was designed on lower first premolar, and restored it by ceramics crown. Under four loading conditions, the tensile stress distributions on the ceramics crown were analyzed to evaluate the relations between three kinds of ceramics crown, which were an aluminous porcelain jacket crown, a feldspathic porcelain jacket crown and an Olympus castable ceramics (O.C.C.) crown, and three kinds of abutment which were a natural tooth, a gold cast core and a composite resin core. And following results were obtained: 1. When the abutment was a natural tooth, the tensile stresses were apt to occur all over the ceramics crown and these magnitude were increased in porportion to the height of Young's modulus of the ceramics materials. 2. When the abutment was a gold cast core or a composite resin core, the tensile stresses were produced only at the loading side of the ceramics crown, and the magnitude of stress were little affected by the type of core materials.

Composite Resins↗
PubMed1989

Permeability of etching agent constituents through dentin.

The in vitro dentin permeability of the constituents of two types of conventional phosphoric acid etching agents which had different viscosities, and their pH changes after being permeated dentin were investigated. It was recognized that, even though the etching was for a short time (one minute) followed by rinsing, the etching agents were still detected in the dentinal tubules which had permeated through the dentin. The results of a qualitative and quantitative analysis of the constituents which had permeated through the dentin showed that, after one minute of etching, the concentrations of calcium, magnesium, zinc and phosphorus increased as compared with the non-etched control samples.

Acid Etching, Dental↗
PubMed1989

[Clinical study of intrahepatic arterial infusion of unresectable hepatoblastoma and hepatocarcinoma in children].

Six cases of unresectable hepatic cancer in infant were treated with intra-arterial infusion therapy. The histological types were hepatoblastoma and hepatocellular carcinoma, 3 cases respectively. The clinical stages were 1 recurrent case in I, 1 in IIIA, 2 in IIIB and 2 in IV. Seldinger method and cannulation at laparotomy were employed in 4 cases and 2 cases, respectively. In the eldest case, a catheter with dual lumen reservoir developed in our department was inserted, making it possible to infuse drugs into hepatic artery and cutting off hepatic arterial blood flow temporarily. The anticancer drug used was ADM, CDDP, 5-FU, THP-ADM, and MMC; antiAFP-anticancer drug conjugate missile therapy was employed in 4 cases. According to image diagnosis, reduction or necrosis of tumor was observed in 5 cases. In all cases, AFP scores decreased. In 5 dead cases, 4 cases died of tumor enlargement (average survival time 16.3 months); 1 case died of DIC during chemotherapy. The other case could eventually undergo complete resection and is now alive. Intra-arterial infusion therapy seemed to be useful for patients of infant unresectable hepatic cancer.

Adolescent↗
PubMed1989

[Prosthodontic considerations in implant therapy].

Numerous factors affect the success or failure of the various intra-osseous implants. In particular, such considerations as the implant materials, properly selected or not, preceded by careful patient screening and thorough analysis of soft and hard tissues, implant insertion conditions, oral hygiene and the overlying prostheses determine the success of the implant therapy. Among these, the final overlying prostheses serve two major purposes of restoring lost masticatory function and esthetic improvement. In addition, due to the intimate relationship with the health and remodeling of the surrounding tissues, the prostheses must be designed with the utmost care. Analyzing this kind of osteointegrated system from the histologic standpoint of the implant/bone relationship, one can roughly classify this system into three types. One is a fibro-osseous integration yielded by enveloping with fibro connective tissue. The other is osseointegration by directly contacting with bone. Lastly, the osteoankylosis form whereby fusion of the implant and bone takes place. Irrespective of the different types and a basic physical principle applied, the function of the final prostheses should be to transmit occlusal force widely to the supporting cortical and basal bones (i.e., jaw bones) via the implant device without creating any undesirable concentrated, rotational or lateral force. Therefore, the final prostheses are not designed independently or after the implant operation. Instead, the prostheses design comes first, followed by careful analysis of the opposing occlusion, proximal dentition and other intraoral structures. Based on the determined existing intraoral environment, the particular type of implant and its form is selected to fit the individual case. Preoperative procedure requires articulator mounted study casts to evaluate the opposing occlusion and implant positioning from which the mesiodistal and buccolingual positioning is determined. Subsequently, the final prosthesis design is prewaxed and the required number of implants and their interspan distances are determined from the wax-up. Next, the Surgical Guide Plate device is employed to help determine radiographically the implant positioning and the anatomical jaw morphology. As mentioned earlier, the purpose of the final prosthesis is to restore the lost masticatory function and esthetic improvement along with presservation of the remaining teeth and harmony with the intraoral soft and hard tissues. Implants serve a critical supportive role of helping the success of the final prosthetic treatment. Intraosseous implants can be used as independent support system or can be combined with remaining natural dentition to support the overlying prosthesis.(ABSTRACT TRUNCATED AT 400 WORDS)

Dental Implants↗
PubMed1989

[Clinical use of castable ceramics (OCC) crown].

The new ceramics material (OCC) was developed for the purpose of aesthetic restration which can be fabricated by an usual lost wax process and it produces accurate marginal fit. OCC possesses mechanical, chemical, and physical properties. This article is discussed utility and security of OCC complete crown on the clinical application from Dec, 1986 to Jun, 1989. The results may be summarized as follows: 1) 2 of 69 cases were broken down in the period from Dec, 1986 to Jun, 1989. These reasons are caused by the lack of occlusal thickness and unsuitable fit of crown. 2) Although 4 of 69 cases are stained by tobacco tar and 5 of 69 cases are suffered from plaque accumulation, these staining and plaque accumulation are improved by plaque control. 3) An allergic reaction or an abnormality of oral tissues haven't been recognized during test period of clinical use. Consequently OCC crown showed itself about safety and usefulness.

Crowns↗
PubMed1989

[Development of a new therapeutic method in hepatocellular carcinoma using a culture system--the intensifying effect of human epidermal growth factor (hEGF) on the antitumor action of antitumor agents].

The culture system of hepatocellular carcinoma (HCC) has been established and the effect of hepatotrophic factors on these cell lines have been studied. During this study the effect of the human epidermal growth factor intensifying anti-tumor action of anti-tumor agents will be evaluated. HCC cell lines (C-HC-4, C-HC-20) show logarithmic growth in the serum-free medium. These growth curves after administration of 1 x 10(-12- -8) M of hEGF were measured, and the existence of the hEGF receptors was evaluated using the ABC method. The growth curve of HC-4 transplanted into nude mice was measured in 4 groups; the control group, the hEGF group, the gamma Interferon (gamma IFN) group, and the hEGF + gamma IFN group. The hEGF enhanced the cell growth of C-HC-4 and C-HC-20, and EGF receptors were confirmed immunohistologically. In the hEGF+ gamma IFN group, growth inhibition seems to be most important. The hEGF may intensify the anti-tumor action of the anti-tumor agents.

Animals↗
PubMed1989

[Adriamycin, cisplatin, and etoposide combination chemotherapy for small cell lung cancer].

Twenty-three patients with small cell lung cancer (11 with limited disease and 12 with extensive disease) who had not received previous chemotherapy were treated with a combination of adriamycin (30 mg/m2, i.v., on day 1), cisplatin (80 mg/m2, i.v., on day 1) and etoposide (70 mg/m2, i.v., on day 1-5). This chemotherapy regimen was repeated at 3- or 4-week intervals for 3 to 5 treatment cycles. Among 22 evaluable patients, 5 showed complete response and 17 had a partial response (response rate 100%). The median response duration of 12 extensive disease patients was 21 months. There were 5 survivors for more than 2 years. Toxicity included moderate to severe hematologic toxicity, alopecia, nausea and vomiting. This combination chemotherapy appears to be optimal for the treatment of small cell lung cancer.

Aged↗
PubMed1989

[A case of pulmonary tuberculosis in a long-term survivor with small cell carcinoma of the lung].

A 64-year-old woman complained of chest pain, back pain and dry cough. Chest X-ray film showed marked left hilar enlargement and left pleural effusion. Biopsy of the bronchial mucosa and demonstrated small cell carcinoma of the lung. Treatment with cisplatin, adriamycin and etoposide led to regression of symptoms and chest X-ray findings within 3 months. She received maintenance chemotherapies at the outpatient clinic for 2 years after the first therapy. Thirty-months after the first admission, chest X-ray film showed multiple small nodules in the left upper lobe. Chest tomography and high-resolution computed tomography showed acinar or lobular nodules disseminated in the left upper lobe. Mycobacterium tuberculosis was obtained from bronchoalveolar lavage fluid of the left upper lobe. Pulmonary tuberculosis in a long-term survivor of small cell carcinoma of the lung is very rare.

Carcinoma, Small Cell↗
PubMed1989

[Quantitative analysis of sulphur in the liquid of some dental cements].

The ceramometal restoration with porcelain margin have been clinically applied to provide accuracy and esthetics. But, we experienced the cases that the color of the labial marginal area of ceramometal restoration turned dark. Then, the crown was removed and observed. And it was found that the cement color had been changed black. As the result of the ultimate analysis of this cement by means of X ray microanalyzer, some elements; Al, P, S, Ca, Ni and Zn, were detected. As the inclusion of sulphur in commercially available cements was suspected the quantitative analysis of sulphur in the liquid of glass ionomer cement and polycarboxylate cement were done by means of inductively coupled plasma spectrometer. And following results were obtained that sulphur was included 5437 micrograms/ml in the liquid of glass ionomer cement, and 2147 micrograms/ml in the liquid of polycarboxylate cement, respectively. From the above, it is suspected that sulphur reacts on dental metal and causes tooth and gingival discoloration.

Dental Cements↗
PubMed1989

Effect of chlorpromazine on transmigration of mitochondrial aspartate aminotransferase in rat liver.

Cholestatic liver injury was experimentally induced in rats by administration of chlorpromazine (CPZ). The peak activity of mitochondrial aspartate aminotransferase (AST) released in serum was found to precede the peak of total AST activity. The liver mitochondria obtained from rats treated with CPZ was fractionated into two subfractions: one containing the intermembrane space, and the other containing the matrix and the membranes. As a results, the relative activity of AST in the intermembrane space was significantly increased at 12 h after CPZ administration. This result suggests that mitochondrial AST, which is dominantly located in the mitochondrial matrix, transmigrated to the intermembrane space via the inner membrane under the effect of CPZ administration.

Animals↗