Haruki Kato

Local secretion of corticotropin-releasing hormone by enterochromaffin cells in human colon

BACKGROUND/AIMS Corticotropin-releasing hormone (CRH) is a regulator of the hypothalamic-pituitary-adrenal axis and a coordinator of the gastrointestinal response to stress. In addition to its central effects, CRH has peripheral effects on the immune system. CRH is present in several human tissues, such as the brain, spinal cord, adrenal medulla, lung, liver, peripheral blood leukocytes, as well as the gastrointestinal tract. The current study examined the local production of CRH in the normal human colon. METHODS Normal human colonic tissues obtained by endoscopic biopsy were immunostained with anti-CRH and anti-5-hydroxytryptamine antibody and analyzed for CRH messenger (m)RNA by a reverse-transcribed polymerase chain reaction method and by in situ hybridization. RESULTS Immunoreactive CRH and CRH mRNA were detected in the colonic mucosal cells in the neighborhood of the base of the crypts. The mucosal cells that expressed CRH mRNA also immunostained with anti-5-hydroxytryptamine antibody. CONCLUSIONS Normal human colonic mucosal enterochromaffin cells produce CRH. CRH in the colonic mucosa may play a role in the modulation of the intestinal immune system and/or other gastrointestinal functions basally during stressful conditions.

C‐MYC antisense oligodeoxynucleotides can induce apoptosis and down‐regulate Fas expression in rheumatoid synoviocytes

OBJECTIVE To investigate the role of c-myc in the pathogenesis of rheumatoid arthritis (RA) and the mechanism of synovial apoptosis. METHODS Using cultured human synoviocytes from patients with RA and c-myc antisense oligodeoxynucleotides (AS ODN), we examined the inhibition of cell proliferation by the MTT assay and the induction of apoptosis with TUNEL staining and fluorescence microscopy. In addition, the effect of c-myc on down-regulation of Fas expression was analyzed by flow cytometry, cytotoxicity assay, and reverse transcriptase-polymerase chain reaction. RESULTS Treatment with c-myc AS ODN induced inhibition of cell proliferation, along with down-regulation of c-Myc protein and c-myc messenger RNA (mRNA) expression. The morphologic changes of synovial cell death were typical of apoptosis. In addition, c-myc AS ODN treatment down-regulated expression of Fas mRNA but not Fas antigen. Analysis of the involvement of the caspase cascade revealed that the cytotoxic activity of c-myc AS ODN was completely blocked by inhibitors of both caspase 1 (YVAD-FMK) and caspase 3 (DEVD-FMK). CONCLUSION Our results strongly suggest that c-myc AS ODN might be a useful therapeutic tool in RA and clarify that cell death by c-myc AS ODN is induced through the caspase cascade, similar to Fas-induced apoptosis. In addition, combination therapy with anti-Fas antibody and c-myc AS ODN reduced Fas-dependent cytotoxicity.

Effects of FUT-175, a New Synthetic Protease Inhibitor on Endotoxin-Induced Disseminated Intravascular Coagulation in Rats

The effects of FUT-175 (6-amidino-2-naphthyl-4-guanidino benzoate-dimethanesulfonate), a new synthetic protease inhibitor, on endotoxin-induced experimental disseminated intravascular coagulation (DIC) were studied in rats. Experimental DIC was induced by a 4-hour sustained infusion of endotoxin at a dose of 100 mg/kg. The rats were infused continuously with FUT-175 at 0.001, 0.01, 0.1, 1.0 or 10.0 mg/kg into a femoral vein for 4 h. Simultaneously with the agent infusion, endotoxin (100 mg/kg/4 h) was administered into the contralateral femoral vein. A protective effect against DIC was noted in the rats treated with 0.01 or 0.1 mg/kg of FUT-175 in the following parameters: fibrinogen and fibrin degradation products, fibrinogen level, prothrombin time, partial thromboplastin time, platelet count and the number of renal glomeruli with fibrin thrombi. These results demonstrated that FUT-175 reduces the extent of changes of the coagulation parameters caused by DIC.

Synergistic effect of HLA class II loci and cytokine gene polymorphisms on the risk of gastric cancer in Japanese patients with Helicobacter pylori infection

It has been reported that polymorphisms of human leukocyte antigen (HLA) genes and several cytokine genes are associated with an increased risk of developing gastric cancer (GC). However, the results of studies from different geographic regions, ethnic groups and study groups are inconsistent. The aim of this study was to evaluate the influence of H. pylori infection and host genetic factors on GC susceptibility in Japanese patients with GC. We analyzed genotypes for HLA class I and II, tumor necrosis factor α, interleukin (IL)‐1β, IL‐1 receptor, IL‐4, IL‐4Rα and IL‐10 in 330 H. pylori‐infected noncardia patients with GC and 190 H. pylori‐infected nonulcer dyspeptic controls. Haplotype analyses indicated that the frequencies of the HLA DRB1*0405 and DQB1*0401 alleles were increased in the patients with intestinal‐type GC when compared with controls (both DRB1*0405 and DQB1*0401: p = 0.015, OR = 1.57, 95% CI = 1.09–2.26), but the changes were not statistically significant after correction for multiple comparisons. None of the cytokine gene polymorphisms were associated with GC susceptibility, whether patients with GC were analyzed as a group according to the histological subtype. Of interest was the comparison of controls and patients with intestinal‐type GC. The frequency of an IL‐10‐592AA homozygote showing concomitant carriage of the HLA DRB1*0405‐DQB1*0401 haplotype was significantly higher in patients with intestinal‐type GC (χ2 = 6.369, p = 0.0116, pc = 0.0464, OR = 2.43, 95% CI = 1.21–4.48). Our results suggest that the HLA class II and IL‐10‐592A/C polymorphisms synergistically affect the susceptibility to GC development of H. pylori‐infected individuals in the Japanese population.

Lipid peroxidation and lysosomal enzymes in D-galactosamine hepatitis and its protection by vitamin E

SummaryRole of Iipid peroxidation on lysosomal instability in liver tissue was investigated in an experimental model of D-galactosamine hepatitis in rats fed on vitamin E (V.E) deficient diet.Administration of D-galactisamine to V.E deficient rats resulted in a sudden increase of serum glutamic oxaloacetic transaminase (sGOT), glutamic pyruvic transaminase (sGPT), lipid peroxide value, as well asβ glucuronidase and acid phosphatase activity examined as markers of lysosomal enzymes, when compared with control rats fed on V.E supplemented diet.Lipid peroxide in the liver tissue also showed significant increase in V.E deficient rats. In contrast, \- glucuronidase and acid phosphatase in the liver tissue were found to decrease in V.E deficient rats by the administration of D-galactosamine, indicating that the enzymes in the lysosome were entirely released outside the liver cells as a result of cell destruction.It is concluded that the increase of lipid peroxide causes the instability of lysosomal membranes and releases various kinds of hydrolytic enzymes to lead further cell damage. V.E might act on inhibiting lipid peroxidation to stabilize lysosomal membranes.

Induction of gene expression for nitric oxide synthase by immunomodulating drugs in the RAW264.7 murine macrophage cell line

Abstract We have elucidated the direct effects of PSK (a protein-bound polysaccharide) and OK-432 (a streptococcal preparation), both immunomodulating drugs, on the gene expression for an inducible nitric oxide synthase and on the production of nitric oxide (NO) in the RAW264.7 murine macrophage cell line. As determined by northern blot analysis, both immunomodulating drugs were potent inducers of gene expression for inducible NO synthase when cells were costimulated with interferon-γ (IFNγ). Expression of mRNA for the enzyme occurred in a dose-dependent manner after 3 h, when 10 – 50 μg/ml PSK or 0.001 – 1 KE/ml OK-432 was used. Furthermore, NO was also produced in response to these drugs, as detected by the Griess reagent reaction. The enhancement of NO synthesis was thought to be mediated, in part, through tumor necrosis factor α (TNFα) induction by these agents, since a neutralizing antibody to TNFα significantly suppressed NO production in RAW264.7 cells stimulated with PSK or OK432 in combination with IFNγ. We speculate that NO production may play a role in tumoricidal and microbicidal activities of PSK or OK-432 in vivo.

Treatment of malignant ascites and pleurisy by a streptococcal preparation OK-432 with fresh frozen plasma—a mechanism of polymorphonuclear leukocyte (PMN) accumulation

A single injection of a streptococcal preparation, OK-432, with fresh frozen plasma (FFP) (or fresh human serum) into the peritoneal or pleural cavity for the treatment of malignant ascites or pleurisy resulted in a complete reduction of ascitic fluid or pleural effusion in 5 out of 11 patients. FFP was used a further source of complement for the effective accumulation of antitumor polymorphonuclear leukocytes (PMNs) by complement-derived chemotactic factors in the cavity. C5a increased in the fluids 3-9 h after the injection and preceded a massive increase in PMNs. C1 inhibitor (C1INH) and C3b inactivator (C3bINA) decreased in several cases 6 h after the treatment. Chemotactic arachidonic acid metabolites, thromboxane B2(TXB2) as a characteristics of TXA2, and leukotriene B4(LTB4) also increased at the same time even in cases where C5a changed only minimally, and may play a role in accumulating antitumor PMNs in the cavity.

Treatment of cancer ascites by intraperitoneal administration of a streptococcal preparation OK-432 with fresh human complement--role of complement-derived chemotactic factor to neutrophils.

The role of complement in the polymorphonuclear leukocyte (PMN)-mediated tumor cell destruction in cancer ascites was investigated in relation to a streptococcal preparation OK-432, a so-called biological response modifier. Incubation of OK-432 with fresh human serum at 37 degrees C for 60 min resulted in the generation of C3a and C5a chemotactic factors. Intraperitoneal (i.p.) injection of the mixture to a patient with cancer ascites revealed an accumulation of PMNs in the ascitic fluid for a longer period with a rapid reduction of the ascitic fluid, than an intraperitoneal injection of OK-432 alone examined in the same patient. PMNs were found to invade clusters of the tumor cells and then form rosettes followed by the destruction of tumor cells. These findings induced by OK-432 continued over 10 days in the presence of fresh serum, while diminished within 3-4 days when OK-432 alone was injected. When fresh human plasma or fresh frozen plasma was used instead of serum and i.p. injected with OK-432 avoiding preincubation, the same cytological and clinical changes were observed in other patients. These data strongly indicate that OK-432 activates human complement either in vitro or in the peritoneal cavity, and induces PMNs to accumulate in the ascitic fluid. Although the mechanism of killing of tumor cells by PMNs is obscure, addition of human serum or plasma to i.p. use of OK-432 seems to be valuable for the management of patients with malignant ascites.

C3b receptor (CR1) on erythrocytes in various diseases

Abstract Complement receptor for C3b (CR1) on erythrocytes was investigated in various diseases by immune adherence hemagglutination (IAHA) using aggregated human IgG. In normal controls, 21 out of 312 (6%) revealed defective CR1 reactivity, and there was no difference in the prevalence of defective CR1 reactivity between female ( 11 157 , 7%) and male ( 10 155 , 6%). Among various diseases examined significantly high prevalence of defective reactivity of CR1 on erythrocytes was seen in systemic lupus erythematosus (SLE) ( 22 30 , 73%) and malignancy of hematopoietic system, especially in acute myelogenous leukemia (AML) ( 6 11 , 55%).

PSK and OK-432-induced immunomodulation of inducible nitric oxide (NO) synthase gene expression in mouse peritoneal polymorphonuclear leukocytes and NO-mediated cytotoxicity.

Abstract We investigated whether PSK (a polysaccharide from the mycelia of Coriolus versicolor) or OK-432 (a streptococcal preparation) can up-regulate inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) production in mouse peritoneal polymorphonuclear leukocytes (PMNs). Six hrs after intraperitoneal injection of mice with PSK (2500 μg/mouse) or OK-432 (100 μg/mouse), mouse peritoneal PMNs were restimulated with PSK (500 μg/ml) or OK-432 (10 μg/ml) plus 100 U/ml of mouse interferon-gamma (IFN-γ) in vitro. Northern blot analysis showed strong synergism between both PSK and OK-432 and IFN-γ for the induction of iNOS gene expression. NO production by PMNs was increased up to 20 μM (2 μM/106 PMNs/24 hrs) as measured by the Griess reagent method when PMNs were restimulated with PSK or OK-432 plus IFN-γ for 24 hrs, although tumor cell killing was not detected. NO concentrations of more than 80 μM were required for P815 tumor cell killing. These results suggest that PMNs produce NO after stimulation with PSK or OK-432 in combination with IFN-γ and may regulate the immune system in vivo, although the NO production induced by these agents is insufficient for tumor cell killing in vitro.