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Biomedical subjects

T Okabayashi

Publications and source records attributed to T Okabayashi.

98 records · Page 6Linked to original sources

Formation of adenosine cyclic 3',5'-phosphate by nonproliferating cells and cell-free extract of Brevibacterium liquefaciens.

The formation of adenosine cyclic 3',5'-phosphate by Brevibacterium liquefaciens ATCC 14929 was studied with the use of nonproliferating cells and cell-free extract. With nonproliferating cells provided by deprivation of sulfate, the formation of this nucleotide was accelerated by adding some amino acids and sugars. Among amino acids tested, alanine and asparagine were most effective. Pentoses were more favorable than hexoses and other sugars. Formation of adenosine cyclic 3',5'-phosphate was observed also with chloramphenicol-treated cells. Experiments on cell-free extract showed that addition of alanine or pyruvate stimulated the formation of adenosine cyclic 3',5'-phosphate from adenosine-5'-triphosphate. When alanine was added to the cell-free system, shaking of the reaction mixture further increased the amount of the nucleotide, but pyruvate was far more effective than alanine. No synergistic effect of alanine and pyruvate was observed. Some enzyme activity was observed which decomposed adenosine cyclic 3',5'-phosphate, but it was weak as compared with adenyl cyclase activity in the presence of pyruvate. From the results obtained, it appears that pyruvate may act as an activating factor of adenyl cyclase in Brevibacterium liquefaciens.

Adenine Nucleotides↗

Adverse affect of blood transfusions on survival of patients with gastric cancer.

The effect of perioperative blood transfusions on the survival rate of patients with gastric cancer was studied. The survival rate of the transfusion group was significantly lower than that of the nontransfusion group in each of the 5 postoperative years. When no adjuvant immunochemotherapy was performed postoperatively, the prognosis was definitely worse in the transfusion group than in the nontransfusion group. Furthermore, the survival rate of the transfusion group was lower than that of the nontransfusion group in both histopathologic classifications of gastric cancer, and it was lower to a statistically significant extent among the well-differentiated types. These results indicate that transfusions might adversely affect postoperative survival of patients with gastric cancer.

Combined Modality Therapy↗

Effects of streptococcal preparation OK-432 on cytokine induction in spleen and tumour tissues of mice bearing MH-134 tumour cells.

Streptococcal preparation OK-432 is a bacterial immunopotentiator extensively used in Japan for adjuvant cancer therapy. Using C3H/He mice bearing MH-134 tumour cells, cytokine inductions of tumour necrosis factor-alpha, interleukin 1 beta, interleukin 6 and interferon-gamma were determined in spleen and tumour tissues by reverse transcriptase-polymerase chain reaction analysis. No significant induction of cytokine mRNA was observed after subcutaneous administration of OK-432 (OK-432, s.c.) or after intratumoural injection of IFN-gamma (IFN-gamma, i.t.), compared with controls, either in spleen or tumour tissues. In contrast, subcutaneous administration of OK-432 followed by intratumoural OK-432 injection (OK-432, s.c. + i.t.) was found to induce some cytokine mRNAs significantly. The mRNA levels of tumour necrosis factor alpha and interferon-gamma in spleen tissue and those of interleukin 1 beta and interferon-gamma in tumour tissues were significantly elevated in mice with OK-432, s.c. + i.t. treatment compared with controls. These results suggest that treatment with OK-432, s.c. + i.t. effectively induced splenic antitumour immunity as well as local immunity against tumour cells.

Animals↗

Usefulness of multi-detector row computed tomography for accurate preoperative assessment of pancreatic adenocarcinoma: report of a case.

A 74-year-old female underwent surgical treatment for adenocarcinoma of the pancreatic head. Preoperative multi-detector row computed tomography (MD-CT) demonstrated tumor invasion into the accessory right colic vein and the branch of the middle colic artery (MCA), which was not detected by digital subtraction angiography. MD-CT showed anatomical variants in the left hepatic artery arising from the left gastric artery, and the right posterior hepatic artery arising from the superior mesenteric artery. Three-dimensional reconstruction CT generated a clear picture of the anatomy of the region concerned, which is essential for a safe operation. The MD-CT findings were highly consistent with the intraoperative findings. We have demonstrated that MD-CT is an important and highly accurate modality for pancreatic surgery.

Adenocarcinoma↗

Aberration of p53 and DCC in gastric and colorectal cancer.

We investigated the expression of p53 protein by immunohistochemistry and the expression of deleted in colorectal carcinoma (DCC) mRNA by the reverse transcription-polymerase chain reaction (RT-PCR) method in surgically resected tumors of gastric and colorectal cancers and compared these results to the clinicopathological features. Positive immunoreactions of p53 were observed in 21 of 42 gastric cancers (50%) and 25 of 37 colorectal cancers (67.6%). Decreased expression of DCC mRNA was observed in 15 of 38 gastric cancers (39.5%) and 10 of 28 colorectal cancers (35. 7%). There was a significant correlation between the immunoreaction of p53 and the depth of tumor invasion in gastric cancer, as well as between the decreased expression of DCC mRNA and nodal metastasis in colorectal cancer. In early cases without metastasis and invasion beyond muscularis propria, none of six gastric cancers showed a p53 immunoreaction, while seven of 9 colorectal cancers showed positive immunoreactions. On the other hand, two of 4 gastric cancers showed decreased expression of DCC mRNA; whereas, none of the seven colorectal cancers did. Alteration of p53 might occur at a later stage in gastric cancer than in colorectal cancer and be associated with the acquisition of an invasive character. In contrast to gastric cancer, decreased expression of DCC mRNA might be present in a later stage in colorectal cancer than in gastric cancer, and be related to the acquisition of metastatic character to the lymph nodes. In conclusion, alterations of p53 or DCC may play different roles in the progression of gastric cancers as compared to colorectal cancers, and the occurrence of both p53 and DCC genes mutations may cause these cancers to become more malignant.

Colorectal Neoplasms↗