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T Tsujinaka

Publications and source records attributed to T Tsujinaka.

At least 91 records · Page 5Linked to original sources
PubMed1993

The effect of fructose on fructose 2,6-bisphosphate level and fructose 6-phosphate, 2-kinase activity in the perfused rat liver.

In order to investigate the effect of fructose on the metabolic rates of liver glycolysis, changes in fructose 2,6-bisphosphate content and fructose 6-phosphate, 2-kinase (F6P2kinase) activity were examined using perfused rat liver. When the starved liver was perfused with 0.5 mM fructose, the fructose 2,6-bisphosphate level was 6.66 nmol/g liver, or the maximum. However, with further increases in the fructose concentration, increments in the fructose 2,6-bisphosphate level gradually decreased. F6P2kinase was inactive in the starved rat liver. By perfusion with the medium containing fructose or even without fructose, however, the enzyme was activated. The suppression of the increase in the fructose 2,6-bisphosphate level by perfusion at higher fructose concentrations was at least partly due to the inhibition of F6P2kinase by F1P.

Adenosine Triphosphate↗
PubMed1992

Schedule-dependent inhibition of thymidylate synthase by 5-fluorouracil in gastric cancer.

BACKGROUND: An optimal treatment schedule of 5-fluorouracil (5-FU) remains to be clarified. METHODS: A randomized study was conducted to investigate schedule-dependent thymidylate synthase (TS) inhibition by 5-FU in 16 patients with gastric cancer who underwent surgical resection. Surgical specimens of tumor, normal gastric mucosa, and regional lymph nodes were obtained 12 hours after administration of 5-FU either as a continuous infusion (1000 mg/m2 for 48 hours) or as a bolus injection (500 mg/m2 x 2 in 48 hours). RESULTS: The total TS activity (567.8 +/- 294 fmol/mg protein) and the rate of TS inhibition (74.7 +/- 23.1%) in cancer tissues were significantly higher in the continuous-infusion group than in the bolus-injection group (228.5 +/- 104.6 fmol/mg protein and 48.8 +/- 12%, respectively). Likewise, the total TS activity (807.4 +/- 440.3 fmol/mg protein) and the rates of TS inhibition in lymph nodes (72.3 +/- 17.1%) and in normal gastric mucosa (85.1 +/- 12.2%) were significantly higher in the continuous-infusion group than those in the bolus-injection group (232.4 +/- 142.3 fmol/mg protein and 53.6 +/- 17.0% in lymph nodes and 46.5 +/- 14.3% in normal gastric mucosa, respectively). There was a significant correlation between the total TS activity and TS inhibition. CONCLUSIONS: Continuous infusion of 5-FU provides a superior antimetabolic effect in the treatment of gastric cancer, which may lead to a superior antitumor effect.

Aged↗
PubMed1992

Schedule dependent inhibition of thymidylate synthase and tumor growth by 5-fluorouracil in Yoshida sarcoma bearing rats.

Schedule dependent inhibition of thymidylate synthase (TS) and tumor growth by 5-fluorouracil (FUra) was examined in Yoshida sarcoma (YS) bearing Donryu rats. After implantation of YS cells (1 x 10(4), FUra (20 mg/kg/day) was continuously (group C) or daily bolus injection (group B) administered for 6 days. On day 7, tumor weight was 1.57 +/- 0.58 g in group C and 0.45 +/- 0.10 g in group B (P less than 0.01), free TS was 2.23 +/- 83 fmol/mg protein in group B and 96 +/- 55 fmol/mg protein in group C (P less than 0.05), and inhibition rate of TS was 88.3 +/- 5.3% in group C and 94.7 +/- 3.0% in group B (P less than 0.05). A significant correlationship was found between free TS and tumor weight (P less than 0.05). As the next step, continuous infusion (group C) or daily bolus injection (group B) for 6 days was started on day 5 after implantation of YS cells. The relative increase of tumor on day 9 was 256 +/- 111% in group C and 112 +/- 22.1% in group B (P less than 0.05). On day 11, total TS of the resected tumor was 650 +/- 153 fmol/mg protein in group C and 391 +/- 124 fmol/mg protein in group B (P less than 0.05), and inhibition rate of TS was 78.8 +/- 12.4% in group C and 84.4 +/- 8.6% in group B. Daily bolus injection of FUra causes a superior antitumor and antimetabolic effect. The schedule dependent cytotoxicity of FUra should be taken into account when a chemotherapeutic protocol is designed.

Animals↗
PubMed1992

Establishment of a multi-dose study of chondroitin sulfate iron colloid for evaluation of the reticuloendothelial system function.

The assay system of chondroitin sulfate iron colloid (CSFe) was established to evaluate the reticuloendothelial system (RES) function in individual rabbits. In the multi-dose study of CSFe, CSFe was repeatedly administered to each individual rabbit with increasing doses (0.6, 1.2, 2.4, 6.0 mg/kg) at set intervals. Blood samples were serially collected after injection of CSFe and the concentration of CSFe in serum was directly measured as an iron concentration by modifying the previously described assay method [1] to minimize the sample volume. The clearance rate of CSFe at each injected dose was computed by the least-squares method and the double-reciprocal plotting of the doses against the phagocytic velocities by the Lineweaver-Burk method was obtained in each rabbit. The maximum phagocytic velocity (Vmax) and the CSFe concentration producing 1/2 Vmax (Kp) obtained in ten rabbits were 0.129 +/- 0.025 mg/kg per min and 0.417 +/- 0.121 mg/kg (mean +/- S.D.), respectively. The results obtained from this multi-dose study were comparable to our previous results obtained from the mean values of five groups given different doses [1]. The clearance rates of CSFe (0.6, 1.2, 6 mg/kg) decreased after the co-injection of 80 mg/kg of carbon colloid. The calculated Vmax and Kp in 29 rabbits were 0.125 mg/kg per min and 1.167 mg/kg. The Kp was apparently greater than that of the control (Vmax = 0.128 mg/kg per min, Kp = 0.421 mg/kg). Carbon colloid (80 mg/kg) was injected to six rabbits after the completion of the first multi-dose study of CSFe and then the second multi-dose study of CSFe was repeated after 24 h. No differences were found in Vmax and Kp between the two studies as were in the control group (10 rabbits) where saline was injected instead of carbon colloid. These results indicated that carbon colloid (80 mg/kg) gives a competitive and reversible inhibition on the RES. This multi-dose study of CSFe may be applicable for a bed-side analysis of the RES function in a patient.

Animals↗
PubMed1992

Secretion of beta-2-microglobulin from human hepatoblastoma and hepatoma cells on stimulation with interleukin-6.

beta 2-microglobulin (beta 2-M) was secreted in a dose- and time-dependent manner after interleukin-6 (IL-6) treatment of human hepatoblastoma (HuH-6) and hepatoma cells (HuH-7). Pancreatic secretory trypsin inhibitor, which is one of the acute phase proteins secreted in these cells, was also secreted dose- and time-dependently in HuH-6 cells and dose-dependently in HuH-7 cells. It is conceivable that IL-6 induces the production of beta 2-M as an acute phase protein in the liver.

Carcinoma, Hepatocellular↗
PubMed1992

[Effect of intratumoral injection of the mixture of OK-432 and fibrinogen (OK/fbg) on gastric cancer].

We have reported the intratumoral injection of OK/fbg is a very effective immunotherapy for colorectal cancer. In this study, we injected OK/fbg into gastric cancer. Histopathological examinations revealed the formation of fibrin fibers, marked infiltration of inflammatory cells and regression of tumor tissue. Seven days after injection, cytotoxicity of splenic lymphocytes was significantly high and HLA-DR, CD25+ splenic lymphocytes were increased. But there was no significant change in peripheral blood and lymph node lymphocytes. On the contrary, several hours after injection, cytotoxicity and surface markers were changed in peripheral blood and lymph node lymphocytes. However, there was no change in splenic lymphocytes. We suppose that activation of splenic lymphocytes was caused by activation of peripheral blood and regional lymph nodes.

Chemotherapy, Adjuvant↗
PubMed1992

[A study on a postoperative change of beta-2-microglobulin in surgical patients].

Various renal tubular functions were monitored perioperatively in 42 surgical patients and the validity of beta-2-microglobulin (BMG) was evaluated. NAG index (urine NAG titer/urine creatinine), the absolute value of free water clearance and fractional excretion of sodium were worse at 3 to 5 hours after the beginning of operation, indicating the latent renal tubular damage took place during operation. On the other hand, fractional excretion of BMG (FE-BMG; BMG clearance/creatinine clearance) slowly elevated after operation and reached a peak on the 2nd postoperative day. The postoperative change of C-reactive protein (CRP), was similar with that of FE-BMG, showing a significant correlation (r = 0.716, p less than 0.001). The close relationship between CRP and FE BMG was confirmed in 26 patients with or without abnormal liver function who underwent abdominal operation. The peak value of FE BMG was significantly (p less than 0.01) lower in 5 patients with ICG 15' greater than 25% than in 21 patients with ICG 15' less than 20%. Similarly, the peak value of CRP tended to be lower in the former group. In conclusion, FE BMG can not be employed as an indicator of renal tubular function during postoperative period. It reacts as an acute phase reactant like CRP and is probably produced in the liver.

Acetylglucosaminidase↗
PubMed1991

Evaluation of the reticuloendothelial system function by the vascular clearance of chondroitin sulfate iron colloid.

Vascular clearance of chondroitin sulfate iron colloid (CSFe) was evaluated as a test for the reticuloendothelial system (RES) in rabbits. Injected CS59Fe was taken up by the RES in the liver (49%) and bone marrow (41%) after 60 min, suggesting its application for the RES function test. The clearance rate (K-value) of CSFe from the blood was calculated by measuring serum Fe concentrations after releasing iron from CSFe at certain intervals after injection. Depending upon different injected doses, K-values were varied and the phagocytic velocity, computed by multiplying K-values by corresponding injected doses, reached a plateau at high doses, indicating the phagocytosis of CSFe by the RES takes a saturation process. Double-reciprocal plotting of the dose and the phagocytic velocity showed a linear relationship, which provided the data on the maximum phagocytic velocity (Vmax), 0.122 mg/kg/min, and the CSFe concentration producing 1/2 Vmax (Kp), 0.426 mg/kg. Thus, this CSFe clearance test can be used for the evaluation of the RES function.

Animals↗
PubMed1991

Characteristics of various synthetic peptide calpain inhibitors and their application for the analysis of platelet reaction.

Calpeptin (a cell permeable synthetic peptide calpain inhibitor) inhibited the generation of thromboxane B2 (TxB2) by the direct inhibition on Tx synthetase in platelets at the concentrations more than 30 microM. Calpeptin, its analogues and E-64d (EST) were further examined with regard to cell permiability and inhibitory spectra. Among all compounds, only calpeptin inhibited the degradation of substrate proteins of calpain with negligible effect on TxB2 generation in intact platelets at the concentrations less than 30 microM. These concentrations of calpeptin did not inhibit the platelet aggregation, the elevation of [Ca2+], nor the formation of inositol 1,4,5-trisphosphate (IP3) in thrombin or collagen activated platelets. These results indicate that calpain dose not participate in the process of platelet activation induced by thrombin or collagen.

Arachidonic Acids↗
PubMed1990

The effect of heparin on multiple organ failure and disseminated intravascular coagulation in a sepsis model.

In order to elucidate a possible role of hypercoagulability leading to disseminated intravascular coagulation (DIC) in the pathogenesis of multiple organ failure (MOF), unfractionated heparin and the related agents were administered to septic rabbits which manifest DIC and MOF. Administration of heparin resulted in prevention of thrombocytopenia, leukopenia and elevation of plasma bilirubin and creatinine. The morphological hepatic damage was also ameliorated by heparin. Similar favorable effects were obtained by the administration of low molecular weight heparin. Dextran sulfate prevented the hepatic damage to some extent without improvement on other parameters. No significant effect was observed by the administration of a synthetic thrombin inhibitor (MD805). These results indicate that the favorable effect of heparin is due to its anticoagulant property, especially anti-Xa activity. Thereby, it is concluded that the hypercoagulable state leading to DIC is a prerequisite for the occurrence of MOF in sepsis.

Animals↗
PubMed1990

A new method for the quantification of beta-glucan in plasma and its application in the diagnosis of postoperative infection.

In order to correctly diagnose and treat severe postoperative infections, it may be critical to detect and differentiate between endotoxin derived from Gram-negative bacteria and/or beta-glucan derived from fungi. In addition to the chromogenic assay, the turbidimetric kinetic assay has been performed for the quantification of endotoxin in plasma using Limulus amebocyte lysate as previously reported. However, it is also known that beta-glucan triggers the coagulation of Limulus amebocyte lysate. In the present study, the differentiation of beta-glucan from endotoxin and its clinical application were studied. Endotoxin was able to be inactivated in plasma using one-tenth dilution by 10 per cent ethanol or distilled water, followed by heating at 100 degrees C for 120 min, without affecting the activity of coexisting beta-glucan. The treated sample was then subjected to the turbidimetric kinetic assay using Toxinometer ET-201. Using this method, as little as 30 pg/ml of beta-glucan in the plasma may be assayed separately, with the amount of circulating beta-glucan in the plasma of normal subjects being less than 50 pg/ml. On the other hand, in patients with a fungal infection, the amount of beta-glucan in their plasma was elevated significantly. Clinically, beta-glucanemia may often occur in severe postoperative infection even if fungi are not detected.

Candidiasis↗
PubMed1990

Potential participation of calpain in platelet activation studied by use of a cell penetrating calpain inhibitor (calpeptin).

Employing a cell penetrating calpain inhibitor (calpeptin), the role of calpain in platelet activation was examined. In washed platelets (WPs) both thrombin and collagen-induced platelet aggregation were dose-dependently inhibited by calpeptin. The addition of plasma to WPs interfered with the action of calpeptin, however more than 3 min preincubation of calpeptin with WPs completely abolished the influence of plasma. In thrombin-activated WPs with calcium, the increase of intracellular calcium concentration, [Ca2+]i, and the production of inositol triphosphate (IP3) were dose-dependently inhibited by calpeptin. The generation of thromboxane B2 (TxB2) was inhibited by calpeptin in collagen and thrombin-activated WPs. In [3H]-arachidonic acid (AA)-labelled platelets, calpeptin increased the amount of [3H]-AA liberated by inhibiting [3H]-AA degradation after collagen or thrombin stimulation. When [14C]-AA degradation by the platelet suspension was observed, calpeptin inhibited TxB2 and hydroxyheptadecatrienoic acid (HHT) generation but increased prostaglandin (PG) E1, E2, 12-hydroxyeicosatetraenoic acid (12HETE) and AA. Based on these findings, calpain may be involved in the activation phospholipase C and thromboxane synthetase.

Arachidonic Acid↗