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Biomedical subjects

T Tajiri

Publications and source records attributed to T Tajiri.

At least 91 records · Page 5Linked to original sources
PubMed1995

Functional cooperation of MutT, MutM and MutY proteins in preventing mutations caused by spontaneous oxidation of guanine nucleotide in Escherichia coli.

8-Oxo-dGTP (8-oxo-7,8-dihydrodeoxyguanosine triphosphate) is a potent mutagenic substrate for DNA synthesis. The accumulation of 8-oxo-dGTP in the nucleotide pool induces G:C-->T:A transversion as well as A:T-->C:G transversion, and Escherichia coli cells possess mechanisms for preventing such mutations. The mutT gene product specifically hydrolyzes 8-oxo-dGTP to the monophosphate form while the mutM and the mutY gene products function to correct mispairs caused by incorporation of 8-oxoguanine into DNA. From analyses of forward mutations induced in cells lacking 8-oxo-dGTPase (MutT protein) and/or repair enzymes that suppress mutations caused by 8-oxoguanine in DNA (MutM and MutY proteins), cooperative functions of these proteins in control of the spontaneous mutagenesis became evident. In mutator strains lacking MutT and/or MutM proteins, 8-oxoguanine of DNA increased to a concentration expected from the increased rate of mutation.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1995

Cytochrome P4502E1 (CYP2E1) genetic polymorphism in a case-control study of gastric cancer and liver disease.

Cytochrome P4502E1 (CYP2E1) activates carcinogenic N-nitrosamines, benzene, urethane and other low molecular weight compounds. This enzyme is also inducible by ethanol, and metabolizes alcohol. A restriction fragment length polymorphism (RFLP) using the Rsa I restriction enzyme has been identified in the CYP2E1 transcription regulatory region; recent studies suggest that this polymorphism may affect gene expression. We investigated the frequency of the Rsa I RFLP in a Japanese population in relation to gastric cancer and liver disease susceptibility. The frequency of this polymorphism was determined in 150 gastric cancer, 16 hepatocellular cancer, 48 liver cirrhosis and 203 benign gastric disease (controls) patients. This preliminary study shows no association of the specific genotype with gastric cancer in all subjects (odds ratio = 1.04, 95% CI = 0.74-3.08 for the heterozygote and 0.57, 95% CI = 0.22-1.50 for the homozygous rare allele, respectively). To further confirm this lack of association, an age and gender matched case-control study should be performed. Separately, there was no association of the Rsa I RFLP with hepatocellular carcinoma (p = 0.911), but there was a suggested difference between the non-viral associated liver cirrhosis patients and control patients. Thus, this polymorphism may be related to ethanol metabolism and consequential liver diseases in a Japanese population.

Base Sequence↗
PubMed1995

[Clinical evaluation of endoscopic variceal ligation (EVL) using an intensive ligation method].

Endoscopic variceal ligation using an intensive ligation method, or intensive EVL, as we call it, was performed in 17 cases of esophageal varices, from August 1993 to November 1994. Intensive EVL involves making as many ligations as possible from just above the esophago-gastric junction at every session for the complete eradication of varices (F0 and negative Red color sign). Our success rate for the complete eradication of varices was 82.4% (14 out of 17 cases) with the mean number of sessions at 2.2 +/- 0.5 times. The total number of rubber bands used was 20.2 +/- 8.4, with 14.1 +/- 6.0 being used in the initial session alone. The rate of recurrence in complete eradicated cases was 50% (7 out of 14 cases) and the period to recurrence was 6.3 +/- 0.7 months. Although EVL using the intensive ligation method is useful for complete eradication of varices, a high incidence of recurrence in the short term is a concern. We conclude therefore that it is difficult to achieve long term complete eradication of varices with EVL alone, and that additional therapy is needed for long term control.

Adult↗
PubMed1995

[Changes in distribution of reticuloendothelial function in transcatheter arterial embolization (TAE) for hepatocellular carcinoma (HCC), estimated by single photon emission computed tomography (SPECT)].

In order to study the changes in distribution of reticuloendothelial function in transcatheter arterial embolization (TAE) for hepatocellular carcinoma (HCC), the radioactivity of 99mTc-phytate was calculated by the accumulation rate in the organs by means of the single emission computed tomography (SPECT). It was regarded as the reticuloendothelial function in the liver and spleen, and was evaluated independently. Before TAE, significant increases were noted in both splenic activity and splenic volume in the cirrhotic patients, as compared with non-cirrhotic patients. After TAE, the activity in the liver was reduced at the first day after TAE, which returned to the normal level by 5 days. While that in the spleen increased immediately after TAE. After one day of TAE, reticuloendothelial functions of the spleen was significantly higher in the cirrhotic cases then in the non-cirrhotic cases. Furthermore, in the cirrhotic patients, it was significantly higher in the cases embolizated in more than two segments than in those embolizated in one segment only. In conclusion, the reticuloendothelial function of the liver was significantly reduced by the TAE in the cirrhotic patients as compared with non-cirrhotic patients. However the reduced reticuloendothelial function of the liver in the cirrhotic patients was compensated by the increased reticuloendothelial function of the spleen.

Adult↗
PubMed1994

Genomic structure and chromosome location of the human mutT homologue gene MTH1 encoding 8-oxo-dGTPase for prevention of A:T to C:G transversion.

8-Oxo-dGTP (8-oxo-7,8-dihydrodeoxyguanosine triphosphate) is produced by active oxygen species in the nucleotide pool of the cell and can be incorporated into cellular DNA. Human cells contain enzyme activity that hydrolyzes 8-oxo-dGTP to 8-oxo-dGMP, thereby preventing occurrence of mutations, caused by misincorporation. When the cDNA for human 8-oxo-dGTPase was expressed in Escherichia coli mutT- mutant cells devoid of self 8-oxo-dGTPase activity, the elevated level of spontaneous A:T to C:G mutation frequency reverted to normal. We isolated the genomic sequence encoding the enzyme and named the gene MTH1 (for mutT human homologue). This gene is composed of at least 4 exons, spans approximately 9 kb, and is located on human chromosome 7p22.

Amino Acid Sequence↗
PubMed1993

[Two cases of improved quality of life with intra-arterial infusion of CDDP or unresectable gallbladder and pancreatic cancer].

The prognosis of patients with advanced gallbladder and pancreatic cancers is poor. Intra-arterial infusion chemotherapy with CDDP was imported in patients with unresectable gallbladder cancer (First case) and pancreatic cancer (Second case). The values of CEA and CA 19-9 were reduced after chemotherapy in the first case, but the CA 19-9 level was not reduced in the second case. Their hospital free survival (HFS) has been more than one year and they could return to their respective occupations. QOL was thought to be improved when considering their HFS. Intra-arterial infusion of CDDP might be one of the multimodal therapies to improve QOL for patients with unresectable gallbladder and pancreatic cancers.

Cisplatin↗
PubMed1992

[Significance of embolization therapy for esophagogastric varices].

To evaluate the efficacy of the embolization therapy (Emb) for varices, we performed endoscopic injection sclerotherapy (EIS) alone and EIS combined with Emb. Various embolizations such as percutaneous transhepatic obliteration, splenic artery embolization and left gastric artery embolization have been employed. The efficacy rates were 76.5% of the patients in the EIS alone and 87.5% in the EIS with Emb group (EIS+Emb). The cumulative percentages of rebleeding at one year and 3 years were 23.1%, 34.6% in EIS alone, and 10.7%, 25.0% in EIS+Emb respectively. Especially in the patients with the Child C, there was significant difference in the efficacy rates: 60.0% (EIS alone) versus 88.9% (EIS+Emb), and recurrence rates within one year: 41.7% (EIS alone) versus 12.5% (EIS+Emb) (p < 0.05) and length of treatment free periods: 9.7 months versus 17.5 months (p < 0.01). After the treatments, improvement of Child's criteria was seen to be better in EIS+Emb than in EIS alone. The similar results have been obtained in the patients with hepatocellular carcinoma and with gastric varices. These results suggest that EIS should be combined with Emb to increase durability and to improve general condition.

Adult↗
PubMed1990

[Immunohistochemical study on epidermal growth factor and its receptor in human pancreatic carcinoma].

We investigated immunohistochemical expressions of the epidermal growth factor (EGF) and the epidermal growth factor receptor (EGFR) in 25 cases of pancreatic carcinoma, including 13 cases of metastatic lymph nodes. EGF and EGFR were stained mainly in the cytoplasm and on the surface of some pancreatic carcinoma cells, with positive rates of 18/25 (72%) and 9/25 (36%) respectively. In all cases EGFR was noted only when EGF was also detected. EGF and EGFR were stained frequently in differentiated types. In metastatic lymph nodes, EGF and EGFR were found in 54% and 15% respectively, and they were detected only when they were also noted in the same patient's primary lesions. EGF and EGFR were found more frequently in Stages III and IV than in Stage II. These results emphasize that EGF and EGFR may promote both the proliferation and the differentiation of human pancreatic carcinoma cells, as in other sites.

Adult↗
PubMed1989

Portal hypertension secondary to intrahepatic arterio-portal shunt in primary amyloidosis: a case report.

Portal hypertension is a rare complication in hepatic amyloidosis. We experienced a case of a 40-year-old man with primary amyloidosis and advanced esophageal varices. Angiographic procedures clearly demonstrated portal hypertension secondary to intrahepatic arterio-portal shunting. Hepatic arterial embolization brought about a disappearance of the A-P shunt and portal hypertension, though rebleeding occurred. To our knowledge, this is the first case report in which the pathogenesis of portal hypertension in hepatic amyloidosis was elucidated.

Adult↗
PubMed1989

[Assessment of endoscopic embolization in the management of esophageal varices].

Between February 1984 and September 1987, endoscopic embolization (EE) was performed in 26 patients with esophageal varices. The effects of EE were evaluated with endoscopic findings according to the general rules for recording endoscopic findings on esophageal varices as specified by the Japanese Research Society for Portal Hypertension. 1) When the result was regarded as effective if a patient had Cw, F1, R-C sign (-), Li and Lm or disappearance of varices, the improvement was found in 66.7% for Color, 79.2% for R-C sign, 54.2% for Form and 45.8% for Location after EE. 2) Recurrence of varices was found in 50% of the patients (12/24) and 4 of 12 cases (33.3%) had rebleeding. 3) When the endoscopic findings before and after EE were compared between relapsed and unrelapsed cases, relapsed patients had more unfavorable endoscopic findings, furthermore, the extent of improvements was also worse than that of unrelapsed cases. 4) As complications, slight fever, dysphagia and epigastric pain were found in most cases, however, all were cured conservatively. In conclusion, EE is useful and safety tool for the improvement of endoscopic findings of the patients with esophageal varices.

Adult↗
PubMed1989

Immunohistochemical localization of Na+, K+-ATPase in human normal and malignant pancreatic tissues.

Localization of Na+, K+-ATPase in the human pancreas was investigated immunohistochemically using rabbit antisera against Na+, K+-ATPase of the human kidney. The reaction product existed only on the luminal surfaces of both centroacinar and ductal cells in normal pancreatic tissue, whereas in chronic pancreatitis the localization of Na+, K+-ATPase was found frequently on the luminal surfaces of both centroacinar and ductal cells, and on the basolateral surfaces of some ductal cells. However, in acinar cells, the distribution of Na+,K+-ATPase was not detected in either the normal pancreas or chronic pancreatitis. In pancreatic carcinoma tissues, Na+,K+-ATPase existed very rarely in malignant cells. These results indicate that Na+,K+-ATPase is immunohistochemically localized on the membranes of centroacinar and ductal cells of the human pancreas, and that the antigenicity of Na+,K+-ATPase in pancreatic carcinoma cells differs from that in normal cells.

Chronic Disease↗
PubMed1989

[Management of bleeding esophageal varices--efficacy of emergency embolization therapy].

To increase durability for long term control of bleeding, additional treatment has to be performed. Since Oct. 1979, various embolizations that is percutaneous transhepatic obliteration (PTO), splenic artery embolization (SAE) and left gastric artery embolization (LGE) were introduced as conservative treatments, and have been used singly or concomitantly. Embolization has been employed in order to avoid the high risk of emergency operation. Complete hemostasis and prolonged efficacy could be obtained by introducing various embolizations. No emergency operation has been performed since all of these embolizations were introduced in Jan. 1983. The rates of hemostasis (100%), one month survival (90%), 1 year incidence of rebleeding (6.7%), 1 year survival (75.5%) and 3 year survival (62.5%) of emergency cases which received combined embolizations were better than the results of the cases which received emergency operation or endoscopic sclerotherapy alone. Moreover, the patients with gastric varices, including bleeding gastric varices treated with various combined embolizations, showed results of diminished varices in 78.9% of the patients. Thus to increase durability for long term control of bleeding, embolization should be combined according to the patient's hemodynamics, which may result in its extended application.

Embolization, Therapeutic↗
PubMed1988

Modification of DNA by mitomycin C in cancer patients detected by 32P-postlabeling analysis.

DNA adducts of mitomycin C (MMC) were detected by 32P-postlabeling analysis in both surgical specimens and an autopsy sample of the liver of patients with hepatocellular carcinoma who had received chemotherapy with MMC. Four kinds of adducts were detected in all 6 patients treated with MMC. These adducts had identical chromatographic mobilities to those of adducts in the liver of rats treated with MMC, but 1 additional adduct was detected in rat liver. In patients treated with MMC, about 3 adducts/10(8) nucleotides were found 4 days after MMC treatment, and 1 adduct/10(8) nucleotides 14 days after treatment and the latter level was maintained for up to 56 days. MMC-DNA adducts were also detected in peripheral blood leukocytes from a patient 1 and 7 days after MMC treatment, at levels of 1 and 0.6 adduct/10(8) nucleotides, respectively. These results suggest the tumor-initiating activity of MMC in humans.

Animals↗
PubMed1988

[A case report of non-functioning adrenal carcinoma diagnosed by percutaneous needle biopsy and which responded to preoperative chemotherapy].

A 51-year-old female complained of right upper abdominal pain. Non-functioning adrenal carcinoma was suspected from the laboratory data of elevated lactate dehydrogenase level and total amount of urinary excretion of 17-ketosteroid. To deny the possibility of other diseases, such as retroperitoneal sarcoma, a percutaneous needle biopsy of the tumor was carried out. As the pathological diagnosis was adrenal carcinoma, pre-operative chemotherapy consisting of cis-dichlorodiammineplatinum (CDDP), adriamycin, 5-fluorouracil, cyclophosphamide and o,p'-DDD was carried out twice. The tumor size decreased after chemotherapy, and we could operate on the patient safely and relatively easily. Almost all of the tumor was replaced by a necrotic mass. However, cancer cells still remained in the peripheral lesion of the tumor, and the pathological diagnosis was the same as that of biopsy specimen. Although chemotherapy of adrenal carcinoma has not been established yet, we believe from the experience of this case that this disease should be treated by chemotherapy including CDDP.

Adrenal Cortex↗