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Biomedical subjects

A Yamaguchi

Publications and source records attributed to A Yamaguchi.

At least 523 records · Page 29Linked to original sources
PubMed1991

[Clinical effect of postoperative adjuvant chemotherapy for advanced colorectal cancer--comparisons of between tegafur (FT) and UFT].

A randomized controlled study was conducted on a FT 600 mg/day daily oral administration group and a UFT 400 mg/day daily oral administration group as an adjuvant chemotherapy after curative operation for colorectal cancer patients with injection of Mitomycin 30 mg (20 mg during operation and 10 mg on the day following), and the results were examined. FT and UFT were administered orally for one year from the 3rd week after operation. The 5-year survival rate was slightly higher in the UFT administration group. Five-year survival was 82.7% for colon cancer and 82.1% for rectal cancer in the UFT administration group, against 72.6% and 72.0 % in the FT administration group. The same trend was observed when the survival rate was studied by various factors such as the size of tumor, depth of cancer invasion of the wall, histological type, lymph node metastasis, vascular invasion and the degree of progression. There was no difference between both groups in the patterns and times of recognition of the recurrences and in the appearance rate of side effects. The results suggest that UFT 400 mg/day is equal to or better than FT 600 mg/day in therapeutic effect for colorectal cancer patients, although the UFT dose is only 2/3rd the FT dose.

Administration, Oral↗
PubMed1991

[Surgical repair of Scimitar syndrome with azygos connection by extracardiac conduit between right pulmonary vein and left atrium].

We present a surgical case of 41-year-old woman with Scimitar syndrome. Preoperative catheterization showed azygos connection and L-R shunt ratio of 45% without intracardiac malformations. To our knowledge, this combination has not been previously reported. At operation the right single pulmonary vein was found and drained into the inferior vena cava below the diaphragm. Because of counter clockwise rotation of the heart the distance of the scimitar vein and the left atrium was too long for direct anastomosis, a polytetrafluoroethylene tube (10 mm in diameter) was utilized for an extracardiac conduit using cardiopulmonary bypass. Postoperative course was uneventful. We conclude that this technique is effective for this syndrome with a large amount of L-R shunt and a sufficient patency is expected.

Adult↗
PubMed1991

[Significance of intraoperative measurement of secondary regurgitant tricuspid anulus].

We evaluated the dilated tricuspid anuli (10 cases) during operation by means of direct measurement of the lengths of each leaflet anulus and compared with control group whose anuli were normal (12 cases). The lengths of anterior leaflet anulus and posterior one were dilated significantly more than control group. In this study tricuspid regurgitation was mainly proved to be the dilated anterior leaflet anulus. But it was not identified whether the dilatation of posterior one was contributed to the tricuspid regurgitation with the correlation of cardiac output and right atrial pressure from the underlying data.

Dilatation, Pathologic↗
PubMed1991

[CABG in 2 patients with severe left ventricular dysfunction].

Coronary artery bypass grafting was performed in two patients with left ventricular dysfunction (EF 16%). In both cases they had chest pain at rest and ischemic myocardium were detected by the SPECT. We considered them candidate for the operation regardless of LV dysfunction. They were eventful in the postoperative course. One case was discharged and is free from chest pain now, but another unfortunately died for multiple organ failure.

Coronary Artery Bypass↗
PubMed1991

[Left ventricular-right atrial shunt due to infective endocarditis--report of a case].

Acquired left ventricular-right atrial shunt is a very rare cardiac disease. Infective endocarditis, cardiac operative procedures, and thoracic trauma were reported as origins. We report a case of a patient with left ventricular-right atrial shunt due to infective endocarditis. A 53-year-old male who had aortic regurgitation due to infective endocarditis developed suddenly severe congestive heart failure. Two-dimensional and pulsed doppler echocardiography demonstrated left ventricular-right atrial shunt. Emergency operation was done. The fistula was found through the atrioventricular membranous septum. The position from the left view was just below the commissure between the right coronary cusp and non coronary cusp and the opening position from the right view was just above the septal leaflet of tricuspid valve. Aortic valve replacement and direct closure of fistula were done and patient's recovery was uneventful. Case reports of left ventricular-right atrial shunt due to infective endocarditis have been rarely seen, most of which were followed by poor prognosis. Surgical intervention in acute phase is recommended.

Endocarditis, Bacterial↗
PubMed1991

[Clinical experience of autotransfusion of shed mediastinal blood using a new chest drainage unit].

The autotransfusion system (ATS) of shed mediastinal blood is expected as one of the techniques for non-blood open heart surgery. The ATS which has been used previously for this purpose required such items as cardiotomy reservoir, vacuum bottle, infusion pump and was complicated to manipulate. This time we have used a new chest drainage unit, Sentinel Seal Autotransfusion System (Sherwood Medical Co.), and report our clinical experience. This unit consists of two component parts. One is a blood collection bag which is later used for reinfusion of shed blood. The other part is a regular chest drainage unit with the water seal which protects pleural cavity from atmosphere. We used this system for 24 cases of open heart surgery and studied about the hematological and biochemical changes after reinfusing the shed blood postoperatively. There were no complications and side effects related to the reinfusion. The unit we have used is simple to handle and is useful when returning shed blood. We believe that this unit is quite safe for clinical use and that it will become a new strong support for non-blood open heart surgery.

Blood Chemical Analysis↗
PubMed1991

Relation of proliferative activity to survival in patients with advanced gastric cancer.

The proliferative activities of 98 biopsied specimens of advanced gastric cancers were measured by the in vitro bromodeoxyuridine (BrdU) labelling method. BrdU labelling indices (LIs) varied from 4.8 to 45.1%. There was no correlation of BrdU LIs and histological type, distant metastasis, serosal invasion, macroscopic type or tumor size. However, BrdU LIs of tumors with lymph node metastases were significantly higher than those without them. Patients with tumors showing high BrdU LIs had a three-fold relative risk of death, as compared with those showing low BrdU LIs. When the BRdU LIs and all the clinicopathological parameters were entered simultaneously into the Cox model, BrdU LIs, peritoneal dissemination and serosal invasion emerged as independent prognostic parameters. These results indicate that the in vitro BrdU labelling method using biopsied materials may be useful in predicting lymph node metastasis preoperatively and designing operative procedures for individual patients.

Bromodeoxyuridine↗
PubMed1991

[The surgical results of pancreatoduodenectomy and total pancreatogastrectomy combined with autotransplantation of the distal half of the pancreas for the treatment of advanced gastric cancer located in the lower half of the stomach].

In the last 16 years we employed pancreaticodudenectomy (PD) on 27 patients with cancers of the distal third of the stomach, associated with duodenal invasion, invasion to pancreatic head, or n3 metastasis. More recently, total gastrectomy and total pancreatectomy combined with heterotopic autotransplantation of the distal pancreas (TGTP) was performed in 7 patients with n4 metastases. These cases were compared with 56 patients who underwent subtotal gastrectomy (SG) in the same period. When the survival rates were compared, PD provided better long-term results than SG, especially on the patients with tumors infiltrating into the pancreas head. On the contrary, there was no significant survival advantage in patients with duodenal invasion or n3 metastasis between PD group and SG group. TGPT showed the longest survival for the patients with n4 metastasis. These results indicate that PD is a rational and safe method for the treatment of gastric cancer infiltrating into the pancreas head. In addition, TGTP may be the most radical procedure for the treatment of gastric cancer with n4 metastases.

Duodenum↗
PubMed1991

[Clinical significance of immunophenotype in diffuse non-Hodgkin's lymphoma: with special emphasis on the clinical characteristics of T-cell lymphoma].

The clinical significance of immunophenotyping of the non-Hodgkin's lymphomas (NHL) is still controversial. Therefore, we evaluated the prognostic significance of T- and B-cell phenotype in 102 patients having diffuse non-Hodgkin's lymphoma who had been treated in a majority with Adriamycin-containing regimens. The significant differences in pretreatment clinical variables between the two patient groups were the higher frequency of markedly elevated LDH (greater than or equal to X 2 normal) and the lower frequency of decreased cholesterol level in B-NHL (p less than 0.05). Patients with B-NHL had a higher complete remission (CR) rate (77% vs 59%: p = NS), a significantly better overall survival (62% vs 34% at 3-years: p less than 0.05) and longer duration of remission for all patients (50% vs 27% at 3-years: p less than 0.05). Among forty-five patients with stages III and IV disease of nodal origin (excluding those with diffuse small cleaved histology), the B-cell group was associated with a better prognosis; a higher CR rate (68% vs 41%: p = NS) and a longer duration of remission for all patients (44% vs 12% at 2-years: p less than 0.05). Furthermore, for patients with T-cell phenotype, the primary site was the only prognostic factor; the patients whose disease originated from Waldeyer's ring, nasal cavity, and paranasal sinuses, achieved a better CR rate (92% vs 40%: p less than 0.05) and a longer duration of remission for all patients (48% vs 15% at 2-years: p less than 0.05). We conclude that advanced T-cell lymphoma of nodal origin is a subgroup of patients with very poor prognosis if treated with less intensive chemotherapeutic regimens.

Adolescent↗
PubMed1990

Ca2(+)-independent secretory mechanism of thyrotropin-releasing hormone (TRH) involves protein kinase C in rat pituitary cells.

Thyrotropin-releasing hormone (TRH) stimulates biphasic prolactin (PRL) secretion from rat pituitary GH3 cells. The pretreatment of cells with EGTA (100 microM) plus arachidonic acid (15 microM), a condition which decreased TRH-responsive intracellular Ca2+ pools, eliminated the activity of TRH on burst PRL secretion (2 min) but did not alter that on sustained PRL secretion (30 min). However, the treatment of cells with EGTA, arachidonic acid and H-7 (300 microM), a potent inhibitor of protein kinase C (PKC), almost completely suppressed the activity of TRH for sustained PRL secretion. In cells down-modulated for PKC, TRH abolished this Ca2(+)-independent sustained PRL secretion. These results suggest that TRH acts through a separate, Ca2(+)-independent secretory mechanism, besides by modulating the Ca2(+)-dependent mechanism and that PKC is involved in this Ca2(+)-independent secretory pathway.

Animals↗
PubMed1990

IL-6 is produced by osteoblasts and induces bone resorption.

To examine the possible involvement of IL-6 in bone metabolism, a mouse osteoblastic cell line (MC3T3-E1) and primary osteoblast-like cells from fetal mouse calvaria were cultured with several systemic and local bone-resorbing agents and their expression of IL-6 mRNA was determined. Local bone-resorbing agents such as IL-1 alpha, IL-1 beta, TNF-alpha, and LPS greatly induced IL-6 mRNA expression in both MC3T3-E1 cells and primary osteoblast-like cells. Parathyroid hormone slightly increased expression of IL-6 mRNA in primary osteoblast-like cells but not in MC3T3-E1 cells. Neither IL-6 nor 1 alpha,25-dihydroxyvitamin D3 increased expression of IL-6 mRNA in either of the osteoblast-like cells. In agreement with the expression of IL-6 mRNA, biologically active IL-6 was produced in response to the treatment with IL-1 alpha, TNF-alpha, and LPS in MC3T3-E1 cells. Adding IL-6 dose dependently stimulated the release of 45Ca from prelabeled fetal mouse calvaria. Simultaneously adding suboptimal concentrations of IL-6 and IL-1 alpha induced bone resorption cooperatively. In accord with the increase in the release of 45Ca by IL-6, there were three times as many osteoclasts in the bone sections of calvaria cultured with IL-6 for 5 days as in the controls. IL-6 slightly suppressed alkaline phosphatase activity and collagen synthesis in MC3T3-E1 cells. These results indicate that IL-6 is also produced by osteoblasts, preferentially in response to local bone-resorbing agents, and it induces bone resorption both alone and in concert with other bone-resorbing agents.

Alkaline Phosphatase↗
PubMed1990

The non-osteogenic mouse pluripotent cell line, C3H10T1/2, is induced to differentiate into osteoblastic cells by recombinant human bone morphogenetic protein-2.

The possibility that the non-osteogenic mouse pluripotent cell line, C3H10T1/2 (10T1/2), could be induced to differentiate into osteogenic cells by various hormones and cytokines was examined in vitro. Of a number of agents tested, recombinant human bone morphogenetic protein-2 (rhBMP-2) and retinoic acid induced alkaline phosphatase (ALP) activity in 10T1/2 cells. rhBMP-2 also induced mRNA expression of ALP in the cells. Dexamethasone, 1 alpha, 25-dihydroxyvitamin D3, transforming growth factor-beta 1 and insulin-like growth factor-I did not stimulate ALP activity. Treatment with rhBMP-2 greatly induced cAMP production in response to parathyroid hormone in 10T1/2 cells. No ALP activity was induced in NIH3T3 fibroblasts treated with rhBMP-2 or retinoic acid. These results indicate that 10T1/2 cells have a potential to differentiate into osteogenic cells under the control of BMP-2.

1-Methyl-3-isobutylxanthine↗
PubMed1990

Metal-tetracycline/H+ antiporter of Escherichia coli encoded by a transposon, Tn10. The role of the conserved dipeptide, Ser65-Asp66, in tetracycline transport.

The transposon Tn10-encoded tetracycline resistance protein functions as a metal-tetracycline/H+ antiporter (Yamaguchi, A., Udagawa, T., and Sawai, T. (1990) J. Biol. Chem. 265, 4809-4813). The Ser65-Asp66 dipeptide is conserved in all known tetracycline antiporter proteins and is an important target for site-directed mutagenesis. When Asp66 was replaced by Asn, the transport activity was completely lost, whereas when it was replaced by Glu, the activity was reduced to 10% of the wild-type level, indicating that a negative charge at position 66 is essential for tetracycline transport. Replacement of Ser65 by Cys or Ala, in contrast, caused only a minor change in tetracycline transport activity. However, the Cys65 mutant antiporter was sensitive to sulfhydryl reagents. Complete inactivation of the Cys65 antiporter by N-ethylmaleimide was not prevented by the substrate. A less bulky reagent, methyl methanethiosulfonate, caused partial inactivation of the Cys65 antiporter without changing its affinity to the substrate. These results indicate that a region including the dipeptide plays an important role in metal-tetracycline transport except for substrate binding. It may act as a gate which opens on the charge-charge interaction between Asp66 and the metal-tetracycline.

Amino Acid Sequence↗
PubMed1990

Secondary signals mediated by GPIIb/IIIa in thrombin-activated platelets.

We have previously found that stimulation of aequorin-loaded platelets by thrombin produced a two-peaked increase in intracellular free calcium concentration ([Ca2+]i), and the development of the second peak of [Ca2+]i was closely related with the aggregation. In this report, we studied the interrelationship between the GPIIb/IIIa complex, aggregation, cytoskeletons and [Ca2+]i of platelets. The pretreatment of the platelets with dihydrocytochalasin B (4 microM), an actin polymerization inhibitor, did not inhibit aggregation and TXB2 production, but did inhibit both actin polymerization and the second peak of [Ca2+]i increase induced by thrombin, suggesting that actin polymerization and the second peak of [Ca2+]i are interrelated. GRGDSP (100 microM), a synthetic anti-adhesive peptide, has already been reported to inhibit platelet aggregation and the second peak of [Ca2+]i induced by thrombin. It also inhibited actin polymerization and TXB2 production, suggesting that aggregation was important for not only the generation of the second peak of [Ca2+]i but also for actin polymerization and TXB2 production. PGI2 (5 nM) did not abolish but only delayed aggregation, TXB2 production, actin polymerization and the second peak of [Ca2+]i increase. These findings suggest that the secondary signals are caused by aggregation (fibrinogen-binding to the GPIIb/IIIa) in thrombin-aggregated platelets, which results in the TXA2 production and the secondary peak of [Ca2+]i increase, and the latter was dependent on actin polymerization.

Actins↗
PubMed1990

Orientation of the carboxyl terminus of the transposon Tn10-encoded tetracycline resistance protein in Escherichia coli.

A site-directed antibody was generated against a synthetic polypeptide corresponding to the 14 amino acid residues of the carboxyl terminus of the Tn10 TetA protein. The antibody reacted preferentially with inside-out vesicles, rather than right-side-out vesicles, prepared from Escherichia coli cells harboring transposon Tn10. When inside-out vesicles were treated with trypsin, the TetA protein was completely digested in the vicinity of the carboxyl terminus, as judged on immunoblot analysis using the antibody. In contrast, when right-side-out vesicles were treated with trypsin, the TetA protein was hardly digested. These results indicate that the carboxyl terminus of TetA is exposed to the cytoplasmic side of the membrane.

Amino Acid Sequence↗