Biomedical subjects

T Tobe

Publications and source records attributed to T Tobe.

At least 91 records · Page 5Linked to original sources

PubMed1994

Specific PCR amplification for N-ras mutations in neoplastic thyroid diseases.

We analyzed point mutations of N-ras protooncogene codon 61 in thyroid neoplasms by means of a mutation-specific PCR method. In this method, one of the paired primers has a base at the 3' terminal that is complementary to a mutated base of the DNA sequence to be analyzed. With this primer, only alleles which have the same mutation can be amplified. Among 24 thyroid tissues, we detected 2 point mutations out of 7 follicular carcinomas (29%). One tumor had a cytosine to adenine substitution mutation at the first base of codon 61, and the other had an adenine to guanine substitution mutation in the second base of the same codon. The same mutations were not detected in 7 follicular adenomas or 1 papillary carcinoma. These results were confirmed by both dot blot hybridization and direct sequencing method. Mutation of N-ras codon 61 may be significant in malignant transformation of follicular thyroid tumors. Because of its easy availability, the mutation-specific PCR method is a useful screening test for N-ras mutations.

Adenocarcinoma, Follicular↗

PubMed1994

[The role of repeat transurethral resection in stage A1 carcinoma of the prostate].

In order to evaluate the significance of repeat transurethral resection (TUR) in differentiating stage A1 prostatic adenocarcinoma from those with stage A2, we performed repeat TUR in 34 patients with an initial diagnosis of stage A1 prostatic adenocarcinoma. It was found that residual adenocarcinoma was present in five cases (14.7%), but the diagnosis was changed from stage A1 to stage A2 in only one case (2.9%). In one patient with final diagnosis of stage A1 carcinoma, bone metastases were detected seven months after the repeat TUR. It was concluded that repeat TUR for stage A1 prostatic adenocarcinoma did not yield clinically significant information.

Adenocarcinoma↗

PubMed1994

[Laparoscopic pelvic lymphadenectomy for localized prostate cancer].

Between April 1992 and May 1993, 13 patients (age, 66-79) with localized prostate cancer underwent laparoscopic pelvic lymphadenectomy at Asahi General Hospital. Clinical stage comprised A2 for 3 patients, B1 for 1 and C for 9. Lymphadenectomy covered inner half of external iliac nodes and obturator nodes, from pubic bone to proximal end of umbilical ligament. Operating time ranged from 70 minutes to 133 minutes with median of 102 minutes. The number of total lymph nodes dissected ranged from 3 to 17 nodes with median of 7. Lymph nodal involvement was detected in one patient. Two patients needed laparotomy due to bleeding; from abdominal wall caused at insertion of trocar in one, and oozing of blood for 10 hours after procedure in the other. Other serious complications were not observed. In conclusion, laparoscopic pelvic lymphadenectomy was a good staging procedure for localized prostate cancer.

Aged↗

PubMed1994

[Experimental choroidal neovascularization in the rat].

We successfully produced, highly (78%) reproducible experimental choroidal neovascularization (ChNV) in the subretinal space of pigmented rats with intense diode laser photocoagulation. ChNV in the pigmented rat was characterized by rapid development of neovascular membrane and proliferation of retinal pigment epithelium in the subretinal space. This procedure may be useful as an experimental model for ChNV.

Animals↗

PubMed1993

Loss of 17p, mutation of the p53 gene, and overexpression of p53 protein in esophageal squamous cell carcinomas.

We analyzed mutations of the p53 gene by single-strand conformation polymorphism analysis of polymerase chain reaction products and direct sequencing through all coding exons and exon-intron junctions in 32 cases with esophageal squamous cell carcinoma. Mutations were detected in 15 of 32 (47%) tumor samples, in which G:C to T:A transversions were rather frequent (33%). Previously, we reported deletion of chromosome 17p where the p53 gene is located in 45% of Japanese esophageal squamous cell carcinoma, and here the relationship between mutation of the p53 gene and loss of 17p was analyzed. Mutations were observed in 12 of 16 patients with loss of 17p, whereas only 2 of 11 without loss were positive for mutations, suggesting that mutations of the p53 gene were closely associated with a 17p deletion. Furthermore, we immunohistochemically analyzed the expression of p53 protein in esophageal squamous cell carcinoma tumor tissues using a monoclonal antibody. Five of 6 tumors with missense mutations of the p53 gene were positively stained, while in tumors with nonsense mutations or without mutations of the p53 gene staining was very weak or negative. These results suggest a good correlation between mutations and abnormal expression of the p53 gene.

Aged↗

PubMed1993

Chemical mediators released from hepatic macrophages in primary culture--basic characteristics of human hepatic macrophages and changes in liver cirrhosis.

Chemical mediators released from human hepatic macrophages (HHM phi) in primary cultures were analyzed for their secretory function and probable contribution to the modulation of the host defense system and metabolism in liver cirrhosis. In our basic studies, HHM phi increased dose dependently the release of superoxide (O2-) and interleukin-1 (IL-1) when stimulated by opsonized zymosan, up to 1000 micrograms/dish. PGE2 production showed a relatively narrow range of dose dependency, and larger doses led to a reduction of PGE2 yield in some samples. Next, we compared the mediator release from the HHM phi of patients with liver cirrhosis with that from HHM phi in normal liver. O2- released from HHM phi of 8 patients with liver cirrhosis was significantly decreased (controls, n = 20) (P < 0.01). IL-1 released from the HHM phi of 6 cirrhotic patients tended to be higher than that from the HHM phi of 10 control patients, but the difference was not statistically significant (P < 0.10). PGE2 production, however, was about the same in the two groups. These results suggest that cultured HHM phi have certain basic characteristics in releasing mediators with highly potent specific activities and also that these secretory abilities may change in liver cirrhosis. In conclusion, the analysis of cultured HHM phi may be a very practical way to clarify their inherent abilities and participation in the complicated clinical features of liver cirrhosis.

Carcinoma, Hepatocellular↗

PubMed1993

Altered fluidity of liver plasma membranes following partial hepatectomy in rats.

The fluidity of liver plasma membranes was assessed during regeneration following partial hepatectomy in rats. Fluorescence polarization was measured using 1,6-diphenyl-1,3,5-hexatriene to evaluate the fluidity of liver plasma membranes. The fluorescence polarization value of liver plasma membranes of control rats was 0.189 +/- 0.005 (mean +/- SEM). The fluorescence polarization values decreased initially after a 70% hepatectomy [0.176 +/- 0.003 at 3 hr and 0.174 +/- 0.004 at 6 hr (P < 0.01)] at 3 and 6 hours, but then recovered to preoperative levels (0.181 +/- 0.004, 0.189 +/- 0.004, 0.189 +/- 0.003, 0.193 +/- 0.003, 0.200 +/- 0.002, 0.208 +/- 0.007, and 0.190 +/- 0.003 at 12, 24, 36, 48, 72, 96 hr, and 7 days, respectively). Flow cytometric analysis using anti-bromodeoxyuridine (BrdU) monoclonal antibody was used to investigate the cell kinetics of the regenerating liver after 70% hepatectomy. The proportion of S-phase incorporating BrdU was not increased at 6 or 12 hr, but it then increased to peak of 27.9 +/- 1.9% at 24 hr. Subsequently, at 48, 72, and 168 hr, the proportion decreased to 8.5 +/- 0.6, 5.9 +/- 0.3, and 1.0 +/- 0.1%, respectively. The ratio of phospholipid to cholesterol contents of liver plasma membranes following partial hepatectomy did not significantly change in spite of markedly altered membrane fluidity. Thus, the alteration of membrane function occurs in conjunction with the initiation of the regeneration process following partial hepatectomy. It is suggested that the alteration of membrane fluidity plays an important role in the homeostatic response for cell proliferation.

Animals↗

PubMed1993

Role of pancreatic blood flow and vasoactive substances in the development of canine acute pancreatitis.

To study the role of pancreatic blood flow and vasoactive substances in the development of acute pancreatitis, we measured portal vein blood levels of bradykinin, prostaglandin E2 (PGE2), histamine, serotonin, and pancreatic enzymes, and with an electromagnetic blood flowmeter we recorded gastroduodenal arterial flow (GDAF), superior mesenteric arterial flow (SMAF), and mean arterial blood pressure for 6 hr in dogs with acute hemorrhagic necrotizing pancreatitis induced by the retrograde injection of autologous bile (0.5 ml/kg) into the pancreatic duct. GDAF and SMAF decreased immediately in the early phase of acute pancreatitis (-17.8 +/- 6.1%** at 10 min and -15.8 +/- 7.1%* at 20 min; *P < 0.05, **P < 0.01); portal bradykinin concentration increased quickly (3.2 +/- 1.2 pM at 0 time, 16.2 +/- 5.2 pM* at 5 min, 30.4 +/- 4.8** pM** at 10 min, and 39.6 +/- 15.1 pM* at 20 min). Portal PGE2 concentration increased gradually after the induction of acute pancreatitis, and differences from the control group were significant at 20, 30, and 180 min (1426 +/- 175 pM at 0 time, 1956 +/- 273 pM* at 20 min, 2148 +/- 265 pM** at 30 min, and 3369 +/- 686 pM* at 180 min). Portal histamine and serotonin concentrations increased somewhat, but not significantly. These findings suggest that the injection of bile into the pancreatic duct causes the pancreas to quickly release a large amount of bradykinin into the portal vein, which immediately reduces the pancreatic blood flow in the early phase, thus accelerating the progress of acute pancreatitis.

Acute Disease↗

PubMed1993

Effect of urinary trypsin inhibitor on pancreatic cellular and lysosomal fragility in cerulein-induced acute pancreatitis in rats.

We evaluated the protective effect and the mechanism of action of the trypsin inhibitor, urinastatin, extracted from human urine, in experimental acute pancreatitis induced by a supramaximal dose of cerulein (5 micrograms/kg/hr for 3.5 hr). Urinastatin in a dose of 10,000 units/kg/hr was given by three different methods of continuous infusion: (1) 2 hr before and during cerulein infusion, (2) only during cerulein infusion, and (3) starting 1 hr after the beginning of cerulein infusion and continued for 3.5 hr. In protocol 1 and 2 urinastatin was significantly more protective than in 3. In protocol 1 urinastatin was very protective in all parameters tested (serum amylase level, pancreatic water and amylase content, distribution of lysosomal enzymes, cellular and lysosomal fragility). These results suggest that the administration of urinastatin before and during cerulein infusion may suppress the pathogenesis and evolution of pancreatitis by inhibiting the chain reaction of pancreatic enzyme activation closely related to redistribution of lysosomal enzyme and lysosomal fragility.

Acute Disease↗

PubMed1993

The therapeutic effect of OK-432-combined adoptive immunotherapy against liver metastases from gastric or colorectal cancers.

Twenty-four patients with liver metastases from gastric or colorectal cancer were treated with OK-432-combined adoptive immunotherapy (AIT). Lymphocytes isolated from regional lymph nodes or peripheral blood were cultured with medium containing T cell growth factor and sonicated tumor extract antigen (SE-Ag) for 9-13 days. The cultured lymphocytes were transferred mainly through the hepatic artery after the administration of OK-432, a streptococcal preparation. Sixteen of the 24 patients received a low dose of anti-cancer agents between the OK-432 injection and cell transfer. When cultured without SE-Ag, regional lymph node lymphocytes (RLNL) showed significantly (P < 0.05) higher cytotoxic activity against autologous tumor cells and, on the contrary, lower cytotoxic activity against K562 than peripheral blood lymphocytes (PBL). When cultured with SE-Ag, cytotoxicity of RLNL against autologous tumor cells was nearly equivalent to that of PBL. The blastogenesis of fresh PBL to SE-Ag was significantly (P < 0.05) augmented after the OK-432-combined AIT. Two patients showed complete response and 4 patients showed partial response among 19 patients who had evaluable lesions. Five patients whose liver metastases were resected were treated with OK-432-combined AIT as an adjuvant therapy. To date they are alive without recurrence in the liver.

Adult↗

PubMed1993

Cellular interaction against autologous tumor cells between IL-2-cultured lymphocytes and fresh peripheral blood lymphocytes in patients with breast cancer given immuno-chemotherapy.

In patients with Stage II or III breast cancer and in patients with liver metastases from breast cancer, we examined cellular interaction in the cytotoxicity against autologous tumor cells by interleukin-2(IL-2)-cultured lymphocytes (CL) and fresh peripheral blood lymphocytes (FPBL) treated with immunochemotherapy including OK-432 and cyclophosphamide. In flow cytometric analysis, CD8+CD11b+ and CD16+ cells significantly decreased after immuno-chemotherapy in both groups of patients. A protocol study in Stage II or III breast cancer patients showed suppressive activity of FPBL on the cytotoxic activity of CL in 3/9 of the non-treatment group but no suppressive activity and enhancing activity in 3/7 in the immuno-chemotherapy group. Moreover, in 19 patients with liver metastases from breast cancer treated with immuno-chemotherapy including adoptive immunotherapy, FPBL in 6/19 showed enhancing activity, and in 8/19 suppressive activity in the lysis of autologous tumor cells. In assays in vitro using autologous and allogeneic tumor cells, FPBL showed a partial specificity in cellular interaction against autologous tumor cells. CD4-depleted FPBL inhibited cytotoxicity of CL, while CD8-depleted FPBL enhanced cytotoxicity of CL in patients with liver metastases. These results suggest that immuno-chemotherapy eliminates the suppressive population in FPBL and may induce tumor regression if combined with adoptive immunotherapy using CL.

Adjuvants, Immunologic↗

PubMed1993

The role of HDL consisting of SP-40,40, apo A-I, and lipids in the formation of SMAC of complement.

Soluble membrane attack complex (SMAC, SC5b-9) of complement contained apolipoprotein A-I (apo A-I) and lipids. Since SC5b-9 contained no apolipoprotein A-II (apo A-II), the incorporation of apo A-I and lipids into SC5b-9 was not caused by a non-specific binding of high-density lipoprotein (HDL). The incorporation of apo A-I into SC5b-9 was confirmed by a double agar diffusion immuno-assay. SC5b-9 contained one molecule of apo A-I and 3.5% lipids by weight. The composition of the lipids was phospholipid: total cholesterol: triglyceride = 47.5:45.0:7.5, and the ratio of free cholesterol:esterified cholesterol was 22.3:77.7. Since SC5b-7 contained apo A-I and SC5b-9 free of SP-40,40 contained no apo A-I, the HDL consisting of SP-40,40, apo A-I, and lipids was incorporated into SMAC at the stage of SC5b-7 via SP-40,40 as a binding site.

Apolipoprotein A-I↗

PubMed1993

Determination of carboxyl-terminal residue and disulfide bonds of MACIF (CD59), a glycosyl-phosphatidylinositol-anchored membrane protein.

MACIF (CD59) is a glycosyl-phosphatidylinositol (GPI)-anchored membrane glycoprotein which inhibits the formation of membrane attack complex of human complement. MACIF prepared from human erythrocyte membranes was digested with pronase. When the digest was subjected to two-phase partition with butanol and 0.1 N HCl, the carboxyl-terminal peptide was recovered in the butanol phase because of the attachment of the highly hydrophobic GPI. The amino acid sequence of the peptide was determined to be Asn72 at its amino-terminus and up to Glu76, while the presence of Asn77 was ambiguous. To allow unequivocal determination of the carboxyl-terminus, a soluble form of MACIF was prepared from human urine on a large scale. The carboxyl-terminal peptide from the soluble form was prepared by tryptic digestion followed by reversed-phase HPLC. The sequence and composition of the peptide unequivocally revealed Asn77 as the carboxyl-terminus. The pattern of disulfide bonds of MACIF was also determined with the membrane form as well as the soluble form. Cystine-containing peptides were prepared by chymotryptic and tryptic digestion, purified by HPLC, and their amino acid sequences were determined. The results indicated that disulfide bonds were formed at Cys3-Cys26, Cys6-Cys13, Cys19-Cys39, Cys45-Cys63 (or 64), and Cys63 (or 64)-Cys69.

Amino Acid Sequence↗

PubMed1993

Comparison of survival curves of gastric cancer patients after surgery according to the UICC stage classification and the General Rules for Gastric Cancer Study by the Japanese Research Society for gastric cancer.

OBJECTIVE: This study compared the UICC classification with the General Rules for Gastric Cancer Study (GRGCS) of the Japanese Research Society by analyzing recent results of gastric cancer surgery in Japan. SUMMARY BACKGROUND DATA: The present UICC stage classification for gastric cancer was published in 1987 and the Japanese GRGCS were published in 1985. Both are based on the results of surveys conducted in the early 1970s. METHODS: The survival curves of 926 patients, who underwent gastric cancer surgery between 1982 and 1985 at Kyoto University Hospital and its 31 associated hospitals, were analyzed according to the UICC classification and the GRGCS using SAS computer software. RESULTS: There was no difference in survival rate between UICC stages IA and IB. GRGCS stage III was found to include UICC stages II, IIIA, and IIIB, and GRGCS stage IV included UICC stages IIIA, IIIB, and IV, with significantly different survival rates. In contrast, each UICC stage included different GRGCS stages with no significant differences in survival rates. The survival rate of stage IV patients of both classifications who underwent gastrectomy was significantly higher than that of stage IV patients receiving bypass or exploratory surgeries. CONCLUSIONS: The UICC classification is better than the GRGCS for classifying gastric cancer in Japan. However, UICC stage I does not need to be subdivided into stages IA and IB, and stage IV should be further subdivided into stages IVA and IVB according to the surgery performed: IVA, gastrectomy, and IVB, bypass or exploratory surgery.

Humans↗

PubMed1993

Microcirculatory response of the pancreas to feeding, sham feeding, and truncal vagotomy in conscious dogs.

In this study, changes in the microcirculatory dynamics of the pancreas in response to normal feeding, sham feeding, and truncal vagotomy were investigated to elucidate the involvement of a neural mechanism in the physiological modulation of pancreatic blood flow in the conscious state. Continuous measurement of changes in the microcirculation of the pancreas was performed in conscious dogs by the thermoelectric method. A meat meal was given to six normal dogs, seven dogs constructed with external esophagostomy (sham feeding), and four dogs with truncal vagotomy. In response to normal feeding, pancreatic blood flow attained the peak increase of 65.2 +/- 6.2%, showing a significant and biphasic response until approximately 120 min. After sham feeding, pancreatic blood flow was significantly increased with peak values of 89.0 +/- 19.0%, but thereafter showed a rapid decrease, returning to the basal level already at 7.2 +/- 1.1 min. Although truncal vagotomy significantly and greatly reduced the peak increase of pancreatic blood flow to 28.2 +/- 5.1%, blood flow showed still a significant and sustained elevation above basal. This study provides evidence for the involvement of the neural mechanism in the physiological modulation of the microcirculation of the pancreas in the conscious state. The results strongly suggest that the cephalic phase of the increase in pancreatic blood flow is vagally mediated.

Animals↗

PubMed1993

The absence of a surface protease, OmpT, determines the intercellular spreading ability of Shigella: the relationship between the ompT and kcpA loci.

A large plasmid-encoded protein, VirG, on the bacterial surface is essential for the spreading of Shigella by eliciting polar deposition of filamentous actin in the cytoplasm of epithelial cells. VirG expression from the large plasmid is diminished greatly when it is introduced into Escherichia coli K-12 from Shigella. In an attempt to identify factors affecting VirG expression, we found that the absence of the ompT gene, encoding outer membrane protease OmpT, restored full production of VirG protein to E. coli K-12. Conversely, upon introduction of the ompT gene of E. coli K-12 into Shigella, spreading ability was completely abolished, probably because of the proteolytic degradation of VirG protein by OmpT. Analysis of the DNA sequence of the ompT region indicated that the absence of the ompT gene occurred in Shigella and enteroinvasive E. coli strains, and that the absent DNA segment corresponded to a remnant lambdoid phage structure found in E. coli K-12, which encompasses a 21 kb DNA segment spanning from argU through to the ompT genes. Since ompT is located near purE in E. coli K-12 and a virulence locus for provoking keratoconjunctivitis in the eyes of guinea-pigs, named kcpA, is located near purE in S. flexneri, and the two loci are involved in VirG expression, the KcpA- mutants of S. flexneri 2a constructed were examined for correlation between acquisition of ompT and VirG degradation. Our data suggest that the previous recognition of a kcpA locus in S. flexneri is the result of transfer of the ompT gene from E. coli K-12, giving rise to a KcpA- phenotype. These results indicate that the lack of OmpT protease confers upon Shigella the ability to spread into adjacent epithelial cells.

Amino Acid Sequence↗

PubMed1993

Transcriptional control of the invasion regulatory gene virB of Shigella flexneri: activation by virF and repression by H-NS.

Expression of invasion genes encoded by the large 230-kb plasmid of Shigella flexneri is controlled by the virB gene, which is itself activated by another regulator, virF. Transcription of the invasion genes is temperature regulated, since they are activated in bacteria grown at 37 but not at 30 degrees C. Recently, we have shown that the thermoregulated expression of invasion genes is mediated by thermal activation of virB transcription (T. Tobe, S. Nagai, B. Adler, M. Yoshikawa, and C. Sasakawa, Mol. Microbiol. 5:887-893, 1991). It has also been shown that a mutation that inactivates H-NS, the product of virR (hns), derepresses transcription of virB. To elucidate the molecular mechanisms underlying virB activation, we determined the location of the transcription start site and found it to be 54 bp upstream of the 5' end of the virB coding sequence. Deletion analysis revealed that transcriptional activation by virF requires a DNA segment of 110 bp extending upstream of the transcription start site. By using a protein binding assay with crude extracts of S. flexneri harboring the malE'-'virF fusion gene, which was able to activate virB transcription, two protein species, one of 70 kDa (MalE'-'VirF fusion) and another of 16 kDa (H-NS), were shown to bind specifically to the virB promoter region. DNA footprinting analysis indicated that the VirF fusion and H-NS proteins bound to the upstream sequence spanning from -17 to -117 and to the sequence from -20 to +20, in which virB transcription starts, respectively. In an vitro transcription assay, the VirF fusion protein was shown to activate virB transcription while the H-NS protein blocked it. virB activation was seen only when negatively supercoiled DNA was used as a template. In in vivo studies, virB transcription was significantly decreased by adding novobiocin, a gyrase inhibitor, into the culture medium while virB transcription was increased by mutating hns. These in vitro and in vivo studies indicated that transcription of virB is activated through VirF binding to the upstream sequence of the virB promoter in a DNA-topology-dependent manner and is directly repressed by H-NS binding to the virB transcription start site.

Bacterial Outer Membrane Proteins↗

PubMed1993

Eight genes in region 5 that form an operon are essential for invasion of epithelial cells by Shigella flexneri 2a.

The 7-kb region 5 on the large 230-kb plasmid pMYSH6000 in Shigella flexneri 2a YSH6000 is one of the virulence-associated DNA segments required for the invasion of epithelial cells (C. Sasakawa, K. Kamata, T. Sakai, S. Makino, M. Yamada, N. Okada, and M. Yoshikawa, J. Bacteriol. 170:2480-2484, 1988). To elucidate the functional organization of region 5 and to determine the virulence-associated genes encoded by region 5, we performed insertion and deletion mutagenesis, DNA subcloning, and complete nucleotide sequencing of region 5 and found that region 5 contained 11 open reading frames (ORFs) named ORF-1 through ORF-11 which could be translated into proteins with molecular masses of 15.1, 47.5, 13.2, 33.0, 33.4, 24.2, 9.4, 28.5, 39.9, 9.1, and 10.4 kDa, respectively. Complementation tests of the 14 Tn5-induced noninvasive mutants of region 5 with the above plasmid constructs have indicated that region 5 consists of an operon and that ORF-2 through ORF-9, but not ORF-1, ORF-10, and ORF-11, are essential for invasion, and 7 of 8 ORFs (ORF-2 and ORF-4 through ORF-9) and presumably the remaining ORF (ORF-3) are required for secretion of the Ipa proteins. The transcriptional organization, as determined by a promoter-proving vector, S1 nuclease protection, and primer extension RNA sequencing analysis revealed that region 5 is transcribed from a promoter located 47 bp upstream of the 5' end of ORF-2 for the 47.5-kDa protein and that the promoter activity identified was regulated by the virB gene, the transcriptional activator on the 230-kb plasmid.

Amino Acid Sequence↗