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Biomedical subjects

T Tobe

Publications and source records attributed to T Tobe.

At least 199 records · Page 11Linked to original sources
PubMed1991

Enhancement and hepatocyte-modulating effect of chemical mediators and monokines produced by hepatic macrophages in rats with induced sepsis.

We investigated the production of chemical mediators by hepatic macrophages from rats with sepsis and the modulation of hepatocyte function by these hepatic macrophages. The chemical mediators we measured were superoxide (O2-), TNF, IL-1, and PGE2. Production of these mediators by hepatic macrophages from rats with sepsis was significantly increased. Furthermore, protein synthesis by cultured hepatocytes was inhibited in a co-culture system of hepatocytes and hepatic macrophages from rats with sepsis, and it was even inhibited by the supernatant of cultured hepatic macrophages from septic rats. These results demonstrate that hepatic macrophages are activated in sepsis and may play a role in inducing hepatic dysfunction in sepsis.

Animals↗
PubMed1991

Effect of partial hepatectomy on glucose-stimulated insulin release from perfused rat pancreas.

To investigate the functional reserve of the endocrine pancreas both in the early and in the recovering stage after partial hepatectomy, we evaluated the changes in the secretion of insulin in response to a glucose load in isolated perfused rat pancreas 4 and 7 d after about 70% hepatectomy in rats. Insulin responses to a high glucose load (16.7 mM) were significantly higher in the first stimulation phase (first 10 min (p less than 0.01 at 4 and 7 d), and the second stimulation phase (second 20 min) (p less than 0.01 at 4 and 7 d), after hepatectomy. These results indicate that in the regenerating stage after hepatectomy, the sensitivity of islet B-cells to a glucose load is increased to support the increased glucose metabolism in this stage. Thus, this insulin hypersecretion from B-cells seems to be among the adaptations of the endocrine pancreas after hepatectomy.

Animals↗
PubMed1991

Enhancement of hepatic macrophages in septic rats and their inhibitory effect on hepatocyte function.

In the present study, the function of hepatic macrophages and the modulation of hepatocytes by sepsis-elicited hepatic macrophages were investigated in rats with induced sepsis. The functional state of hepatic macrophages was determined by the following indicators: phagocytic index, protein-synthesizing capacity, and superoxide (O2-) producing capacity. These indices of changes in hepatic macrophages were much higher in rats with sepsis than in healthy controls. Moreover, the activated hepatic macrophages had some biological properties which were different from those of the resident Kupffer cells. It was found that protein synthesis by cultured hepatocytes was inhibited in the co-culture system of hepatocytes and sepsis-elicited hepatic macrophages, and that the supernatant of hepatic macrophages from rats with sepsis also reduced the protein-synthesizing capacity of cultured hepatocytes. Thus, activated hepatic macrophages may play a role in inducing hepatic dysfunction in sepsis.

Animals↗
PubMed1991

Protective effects of gabexate mesilate (FOY) against impaired pancreatic energy metabolism in rat acute pancreatitis induced by caerulein.

A supramaximal dose of caerulein (5 micrograms/kg.hr for 3.5 hours) caused edematous acute pancreatitis in rats, characterized by portal hyperamylasemia (32 +/- 3 U/ml) and pancreatic edema (pancreatic water content, 86 +/- 2%) [control group: amylase, 8 +/- 1 U/ml; water content, 74 +/- 2%]. In this model, increased portal levels of malate dehydrogenase (148 +/- 25 U/ml), increased mitochondrial fragility and impaired pancreatic energy charge level (0.77 +/- 0.05) were also observed [control group: malate dehydrogenase, 54 +/- 11 U/ml; energy charge level, 0.94 +/- 0.03]. Administration of gabexate mesilate, FOY, in a dose of 50 mg/kg.hr for 2 hours before and during the caerulein infusion had a significant protective effect against these pancreatic injuries (portal amylase level, 11 +/- 2 U/ml; MDH level, 72 +/- 19 U/ml; E.C., 0.89 +/- 0.02; water content, 76 +/- 2%). FOY in a dose of 20 mg/kg.hr was partially protective. These results indicate that subcellular organelle fragility and malfunction are closely related to the pathogenesis of acute pancreatitis and suggest the usefulness of FOY in the treatment of this disease.

Acute Disease↗
PubMed1991

Systematic computer-aided search of optimal staging system for colorectal cancer.

Two hundred and ninety-eight patients with curatively resected colorectal cancer were classified into 12 categories according to the depth of tumour penetration (T1-T4), and lymph node status (N0-N2). Using a computer, these categories were grouped into 2-12 stages in every possible combination, so a total of 146,975 logical classifications were generated. The optimal model was selected for each group of classifications with equal stage number, thus giving the greatest prognostic information on 5-year survival according to the Akaike criterion. The results showed that (1) 13% of the total classifications, including 85% of the 3-stage classifications, were better than the Dukes system in predicting our patients' outcomes; (2) the T-level was a stage-determinant even more important than the N-level; and (3) major changes in prognosis occurred at more advanced stages than the classical "turning points". We conclude that in order to find an optimal staging of cancer, systematic computer-aided search through all the possible classifications is necessary, using the appropriate database.

Colorectal Neoplasms↗
PubMed1991

Comparative study on various combination chemotherapies against human gastric cancer xenograft lines of well- and poorly-differentiated adenocarcinomas transplanted in nude mice.

Two human gastric cancer xenograft lines (GC-YN and GC-SF) transplanted in nude mice were employed to evaluate and compare the anticancer effect of seven single anticancer agents and their various combinations. Mitomycin C, cisplatin (Briplatin) (CDDP) and 5-fluorouracil (5-FU) were screened out to be effective against GC-YN and only epirubicin (Farmorubicin) (EPIR) was effective against GC-SF. Combinations of two of these 'effective' agents revealed that FP (5-FU + CDDP) is the most effective two-agent combination regimen against both lines, and some of those 'ineffective' single agents showed synergistic effects against both lines when combined with 5-FU. Moreover, three-agent combinations composed of FP and one of the other five agents were also evaluated to select out the most effective regimen. All the combinations showed higher inhibition on the tumor growth of GC-YN than FP regimen, and FP + adriamycin (Adriacin) (ADR) and FP + EPIR were more effective against GC-SF than FP. However, taking toxic effects into consideration, the results suggest that CDDP + 5-FU + EPIR (FPEPIR) may be the regimen most worthy of clinical trial in the chemotherapy against human gastric cancer.

Adenocarcinoma↗
PubMed1991

Venous bypass grafting for celiac occlusion in radical pancreaticoduodenectomy.

Radical pancreaticoduodenectomy was performed for cancer of the head of the pancreas in a 65-year-old male patient with congenital celiac occlusion. Preoperative angiography revealed that the arterial flow to the liver, spleen, and stomach was supplied via the pancreaticoduodenal arcade and that the dorsal pancreatic artery arose from the superior mesenteric artery. In order to perform radical pancreatectomy with sufficient clearance of lymph nodes and soft tissues around the pancreas, the celiac arterial circulation was reconstructed. The restoration of flow was effected via a saphenous vein graft between the common hepatic artery and the aorta. Postoperative angiography demonstrated patency of the graft. The patient's postoperative course was uneventful.

Adult↗
PubMed1991

Temperature-regulated expression of invasion genes in Shigella flexneri is controlled through the transcriptional activation of the virB gene on the large plasmid.

The invasion phenotype of shigellae is subject to thermoregulation that is known to be expressed through activation of some invasion (inv) genes such as ipaB, ipaC, and ipaD encoded by the large virulence plasmid of Shigella flexneri. The expression of ipa genes is regulated positively by virF through the activation of virB on the plasmid. To identify the mediator for the thermoregulation of the large plasmid, we have studied the effect of temperature on the transcription of virF and virB genes and ipa and the other two inv operons. The results showed that transcription of virB was affected by temperature more strictly than that of virF. Analysis of the mRNA level of virB at different levels of virF transcription indicated that virB transcription depended upon both temperature and virF. On the other hand, transcriptions of ipa and the other two inv operons depended on the activation of virB transcription but not on temperature. By inducing virB transcription from a tac promoter fused with the virB region, invasion ability was restored to a virF-deletion mutant at 30 degrees C as well as at 37 degrees C. By using conditions in which the temperature-dependent expression of the invasion phenotype was circumvented by the induction of virB transcription, intercellular spreading ability in a virF+, virB::Tn5 strain was shown to be expressed even at 30 degrees C. These results suggest that the virB transcription stage is the main target for the thermoregulation.

Blotting, Northern↗
PubMed1991

Virulence-associated chromosomal loci of Shigella flexneri identified by random Tn5 insertion mutagenesis.

Shigellae are the causative agents of bacillary dysentery and are capable of invading epithelial cells, multiplying therein and spreading into adjacent cells. To identify genes on the chromosome associated with the virulence phenotype, 9114 independent Tn5 insertion mutants were isolated in a virulent strain of Shigella flexneri. By using an in vitro assay for intercellular spread or an animal infection model, the Serény test, 50 chromosomal Tn5 mutants with reduced virulence were identified. The 50 mutants were characterized with respect to their virulence phenotypes, including three different mutations that affect invasion of epithelial cells, bacterial metabolism and structure of lipopolysaccharide. Mutants with reduced invasive ability were further characterized and it was found that two of them had decreased levels of IpaB, C and D antigens as well as the mRNA for the ipaBCD operon encoded by the large virulence plasmid, suggesting that positive regulatory elements for the ipaBCD operon are encoded by the chromosome. Assignment of the 50 Tn5 insertions of the mutants to the 19 NotI restriction fragments of the chromosomal DNA has permitted the identification of at least nine virulence-associated chromosomal loci.

Animals↗
PubMed1991

Construction of a physical map of the chromosome of Shigella flexneri 2a and the direct assignment of nine virulence-associated loci identified by Tn5 insertions.

To establish the molecular basis of the chromosomal virulence genes of Shigella flexneri 2a (YSH6000), a Notl restriction map of the chromosome was constructed by exploiting Notl-linking clones, partial Notl digestion and DNA probes from various genes of Escherichia coli K-12. The map revealed at least three local differences in the placements of genes between YSH6000 and E. coli K-12. Using the additional Notl sites introduced by Tn5 insertion, nine virulence loci identified previously by random Tn5 insertions were physically mapped on the chromosome. To demonstrate the versatility of the Notl map in direct assignment of the virulence loci tagged by Tn5 to a known genetic region in E. coli K-12, the major class of avirulent mutants defective in the core structure of lipopolysaccharide (LPS) was examined for the sites of Tn5 insertions. The two Notl segments created by the Tn5 insertion in the Notl fragment were analysed by Southern blotting with two DNA probes for the 5' and 3' flanking regions of the rfa region, and shown to hybridize separately with each of them, confirming the sites of Tn5 in the rfa locus. This approach will facilitate direct comparison genetically mapped Tn5 insertion mutations of S. flexneri with genes physically determined in E. coli K-12.

Chromosome Mapping↗
PubMed1991

Postoperative erythroderma with change of HLA phenotypes from heterozygotes to homozygotes: a report of two cases.

Fatal "postoperative erythroderma" (POE) developed in 2 patients treated with liver lobectomy and the transfusion of fresh blood. Their clinical features and skin-histological findings were indicative of acute graft-versus-host disease (GVHD). The HLA phenotypes of circulating lymphocytes of the 2 patients were heterozygous but became homozygous late in the clinical course and were identical with those of the blood donors. One of the patient's haplotypes was identical with the donor's homozygous haplotype. These findings suggest the mechanism of development of POE in apparently immunocompetent patients. The donor's T lymphocytes are histocompatible with the patient's tissues, are not rejected, and become engrafted. The patient's tissues are not histocompatible with the donor's, so that GVHD develops.

Blood Donors↗
PubMed1991

Effect of a new synthetic ascorbic acid derivative as a free radical scavenger on the development of acute pancreatitis in mice.

The therapeutic effects of CV 3611, a new synthetic free radical scavenger prepared from an ascorbic acid derivative, on choline deficient, ethionine enriched (CDE) diet induced acute pancreatitis in mice were evaluated and compared with those of superoxide dismutase. Time/course studies after subcutaneous injection of CV 3611 in normal mice showed a peak plasma concentration of mean (SEM) 0.54 (0.09) micrograms/ml at one hour, with a gradual decrease over the next 10 hours, while a peak concentration in pancreatic tissue of mean (SEM) 425 (33) ng/g tissue was achieved at three hours and the drug was undetectable at 12 hours. Survival rates and activities of pancreatic enzymes (amylase, lipase, elastase I) were compared in control mice and animals that received CV 3611 before or at the time of feeding the CDE diet. The survival rate was observed in a no treatment group and mice given pretreatment or treatment with CV 3611 or superoxide dismutase. The survival rate was significantly better in the treatment group given CV 3611 (p less than 0.02), but superoxide dismutase had no significant effect on survival. The increases in the three serum enzyme activities were significantly less at 48 hours in the groups given pretreatment or treatment with CV 3611 than in the no treatment group. These results indicate that CV 3611, which has been proved to pass through the cell membrane and to have a long half life in plasma and tissue, had an important therapeutic effect on the development of acute pancreatitis. They also suggest that oxygen derived free radicals may play an important role in the development of acute pancreatitis.

Amylases↗
PubMed1991

Morphological and functional discrepancies in endocrine pancreas after partial hepatectomy in dogs.

To clarify the changes in pancreatic hormones and their role in the regeneration of the liver after partial hepatectomy, we measured the portal levels of insulin and pancreatic glucagon and their responses to a glucose load after about 40% hepatectomy in dogs. The changes in the A and B cells of the islets of Langerhans were examined histologically. In the early stages after hepatectomy portal insulin levels decreased significantly, and the response of portal insulin to a glucose load was lower than in the control sham-operated dogs. Both islet size and the number of B cells increased significantly after hepatectomy. Portal pancreatic glucagon levels increased significantly after hepatectomy, and the response of pancreatic glucagon to a glucose load was not suppressed. The number of A cells also increased significantly. Thus, there were differences between insulin and pancreatic glucagon in their morphological and functional effects after hepatectomy. Although this difference is not clearly understood, there is a possibility that insulin consumption is accelerated in the remnant liver after hepatectomy. Insulin and pancreatic glucagon appear to play important but different roles in the regenerating liver from the morphological point of view.

Animals↗
PubMed1991

Assignment of a human serum glycoprotein SP-40,40 gene (CLI) to chromosome 8.

SP-40,40 is a serum glycoprotein consisting of two different subunits (alpha and beta) assembled into a dimer by disulfide bonds. Northern blot hybridization, using total RNA from several cell lines, showed that SP-40,40 is expressed in glioblastoma and testicular tumor cells, as well as hepatoma cells. Spot blot hybridization of flow-sorted human chromosomes, using a SP-40,40 cDNA fragment as a probe, localized the gene for SP-40,40 to human chromosome 8. This gene has been given the designation CLI, for complement lysis inhibitor, by the Human Gene Nomenclature Committee.

Blood Proteins↗
PubMed1991

Low uracil concentration in the liver might be responsible for the decreased antineoplastic activity of fluoropyrimidines in mice with CCl4-induced chronic liver dysfunction.

Some fluoropyrimidines are considered to be metabolized in liver microsomes. The present study was designed to assess the effect of chronic liver dysfunction on the antineoplastic activity of fluoropyrimidines. Chronic liver dysfunction was induced in BALB/c mice by 8 weeks of CCl4 injections. The 5-fluorouracil (5-FU)-sensitive MOPC-104E and 5-FU-resistant Meth-A cells were inoculated subcutaneously into the mice and then various fluoropyrimidines were administered intragastrically. The antitumor activity of the fluoropyrimidines decreased in mice with chronic liver dysfunction, although the concentration of 5-FU in the tumor of normal mice did not differ from that of mice with liver dysfunction. However, the concentration of uracil in the liver was decreased in mice with chronic liver dysfunction. On the other hand, the percent conversion of Tegafur [1-(2-tetrahydrofuryl)-5-FU] to 5-FU in the normal liver did not differ from that in the dysfunctional liver. These results suggest that low uracil concentrations in the liver may result from chronic liver dysfunction and lead to decreased antitumor efficacy of fluoropyrimidines.

Animals↗
PubMed1991

Functional and structural domains of the sixth component (C6) of human complement.

The effects of serine protease inhibitors, diisopropyl fluorophosphate (DFP) and phenylmethanesulfonyl fluoride (PMSF), on hemolytic activity of C6 were reinvestigated. C6 was inactivated in a range of 1-10 mM by both of the inhibitors as previously reported. Limited proteolytic digestion was also studied to elucidate the functional and structural domains of C6. The major fragments produced by trypsin, plasmin, or lysyl endopeptidase could not be separated unless disulfide bonds were disrupted, but Staphylococcus aureus V8 protease yielded several fragments, each of which was not linked by disulfide bond. When C6 labeled with [3H]DFP was subjected to limited digestion with V8 protease, a fragment with a molecular weight of 38 kilodaltons (kDa) was mainly labeled and other fragments of 53 kDa and 26.4 kDa were also faintly labeled, while fragment 35 kDa wasn't labeled, indicating specific domains reactive with DFP. On the other hand, when C6 with or without DFP treatment was digested with V8 protease and those fragments were incubated with C5 and subjected to sucrose density ultracentrifugation, fragments 53, 38, 35 and 27.5 kDa interacted with C5 in both cases. These results suggest that C6 modified by DFP can interact with C5, and the amino-terminal sequences of fragment 38 and 35 kDa suggest the binding domain of C6 with C5 takes place within the two short consensus repeats.

Complement C6↗
PubMed1991

The clinical status and histopathological factors affecting natural killer cells of peripheral blood lymphocytes in patients with gastric cancer.

The in vivo function of NK cells is still uncertain, and there are various contradictory reports on NK cells in gastrointestinal cancer. In the present study the activity and proportion of NK cells (Leu 11 + cells) in peripheral blood were assessed in 71 patients with gastric cancer, and analysed with respect to the clinical and histopathological factors, such as the clinical stage, tumor size, degree of invasion, metastasis, histology, etc. There were no differences in the proportions and activities of NK cells between normal volunteers and gastric cancer patients. A low NK cell activity was associated with early gastric cancers (carcinoma in the mucosa or submucosa) less than 2 cm in diameter, large advanced tumors (invasion beyond the muscularis propria) greater than 8 cm in diameter, and metastasis of adjacent regional (perigastric) nodes. Liver metastasis did not affect the NK cell activity, however a high NK activity was found in patients with peritoneal dissemination. The NK activity did not correlate with the proportion of Leu 11 + cells in normal volunteers or in patients with early gastric cancer, however the activity and proportion of NK cells correlated with each other in patients with advanced gastric cancer. These results suggest that the preoperative evaluation of circulating NK cells in gastric cancer patients may be beneficial to assess the extent of nodal metastasis, the degree of tumor invasion, and peritoneal dissemination.

Adult↗