Biomedical subjects

H Morimoto

Publications and source records attributed to H Morimoto.

At least 127 records · Page 7Linked to original sources

PubMed1992

FK 224, a novel cyclopeptide substance P antagonist with NK1 and NK2 receptor selectivity.

We have discovered a novel cyclopeptide substance P (SP) antagonist, FK 224 (N-[N2-[N-[N-[N-[2,3-didehydro-N-methyl-N-[N-[3-(2-pentylphenyl )- propionyl]-L-threonyl]tyrosyl-L-leucynyl]-D-phenylalanyl]-L-allo- threonyl]-L-asparaginyl]-L-serine-nu-lactone), which inhibited [3H]SP binding to guinea pig lung membranes in a dose-dependent manner. According to Rosenthal analysis, the inhibitory effect of FK 224 on [3H]SP binding appears to be competitive. In order to clarify the receptor subtype selectivity of FK 224, we have studied the interaction of FK 224 with three tachykinin receptors (NK1, NK2 and NK3) by using receptor binding techniques and in vitro bioassays, and have also compared FK 224 with the novel nonpeptide antagonist, (+/-)-CP-96,345. In binding experiments, FK 224 dose-dependently inhibited [3H]SP binding to rat cerebral cortical membranes (NK1) and [3H]neurokinin (NK) A (NKA) binding to rat duodenum smooth muscle membranes (NK2), but did not affect [3H]eledoisin binding to rat cerebral cortical membranes (NK3). In bioassay experiments, FK 224 inhibited SP-induced contraction of guinea pig ileum (NK1) and NKA-induced contraction of rat vas deferens (NK2) in a dose-dependent manner, but did not affect NKB-induced contraction of rat portal vein (NK3). In contrast, (+/-)-CP-96,345 inhibited SP-induced contraction of guinea pig ileum, but not NKA-induced contraction of rat vas deferens or NKB-induced contraction of rat portal vein. In the presence of FK 224, SP dose-response curves and NKA dose-response curves were shifted to the right in parallel with no depression of the maximal contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Effects of FK224, a novel compound NK1 and NK2 receptor antagonist, on airway constriction and airway edema induced by neurokinins and sensory nerve stimulation in guinea pigs.

FK224 (N-[N2-[N-[N-[N-[2,3-didehydro-N-methyl-N-[N-[3-(2- penthylphenyl)-propionyl]-L-threonyl]tyrosyl]-L-leucynyl]-D- phenylalanyl]-L-allo-threonyl]-L-asparaginyl]-L-serine-nu-lactone) is a novel neurokinin (NK) antagonist that exhibits selectivity for NK1 and NK2 receptors. The effects of FK224 on airway constriction and airway edema induced by NKs and nerve stimulation have been investigated in guinea pigs. FK224 inhibited the contraction of isolated guinea pig trachea induced by substance P (SP, 10(-8) M), NKA (10(-9) M) and NKB (10(-8) M) in a concentration-dependent manner, and the IC50 values were 2.6 x 10(-6), 1.3 x 10(-6) and 2.3 x 10(-7) M, respectively. Tracheal contraction induced by histamine and acetylcholine was not affected by FK224, suggesting a specific effect on NK-mediated responses. FK224 also inhibited the atropine-resistant contraction of isolated guinea pig bronchi induced by electrical field stimulation with an IC50 value of 3.5 x 10(-6) M. In in vivo experiments, FK224 given i.v. inhibited SP (13.5 micrograms kg-1)-, NKA (1.1 micrograms kg-1)- and capsaicin (3.1 micrograms kg-1)-induced airway constriction in guinea pigs with ED50 values of 0.39 mg kg-1, 0.36 mg kg-1 and 1.1 mg kg-1, respectively. FK224 also inhibited SP (1.3 micrograms kg-1)-, NKA (11 micrograms kg-1)- and capsaicin (100 micrograms kg-1)-induced airway edema with ED50 values of 0.14 mg kg-1, 0.29 mg kg-1 and 0.30 mg kg-1, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

[Effect of intratumoral injection of the mixture of OK-432 and fibrinogen (OK/fbg) on gastric cancer].

We have reported the intratumoral injection of OK/fbg is a very effective immunotherapy for colorectal cancer. In this study, we injected OK/fbg into gastric cancer. Histopathological examinations revealed the formation of fibrin fibers, marked infiltration of inflammatory cells and regression of tumor tissue. Seven days after injection, cytotoxicity of splenic lymphocytes was significantly high and HLA-DR, CD25+ splenic lymphocytes were increased. But there was no significant change in peripheral blood and lymph node lymphocytes. On the contrary, several hours after injection, cytotoxicity and surface markers were changed in peripheral blood and lymph node lymphocytes. However, there was no change in splenic lymphocytes. We suppose that activation of splenic lymphocytes was caused by activation of peripheral blood and regional lymph nodes.

Chemotherapy, Adjuvant↗

PubMed1992

Hepatectomy accelerates the growth of transplanted liver tumor in mice.

To study the effect of hepatectomy on the growth of liver tumor, Shionogi Carcinoma 42, a mammary tumor, was transplanted into the liver of mice which had undergone 40% hepatectomy. The liver tumor and the number of pulmonary metastases in hepatectomized mice were significantly larger than those in nonhepatectomized mice. Responses to lectins and IL-2, subpopulations, and cytotoxicity to YAC-1 and P815 cells of splenocytes were assessed to evaluate immunological status. At the initial phase after hepatectomy and tumor transplantation into the remaining liver, NK activity transiently increased, and function of B and T cells, especially of helper T cells, decreased, while B-cell function recovered beyond normal levels in a later phase. These results suggest that liver may play an important immunological role and that the immunological modification after hepatectomy may be responsible for the accelerated growth of liver tumor. Accordingly, some adjuvant immunotherapy may be recommended for the prevention of recurrence after hepatectomy for liver tumor.

Alanine Transaminase↗

PubMed1991

Synergistic effect of tumor necrosis factor-alpha- and diphtheria toxin-mediated cytotoxicity in sensitive and resistant human ovarian tumor cell lines.

Recent studies have demonstrated that diphtheria toxin (DTX) also mediates target cell lysis, and the mechanism of cytotoxicity has many features similar to those of cytotoxicity mediated by TNF-alpha. Thus, we hypothesized that DTX and TNF-alpha, used in combination, may result in either additive or synergistic cytotoxic activity. This was examined on three human ovarian carcinoma cell lines chosen for their differing sensitivities to TNF-alpha and DTX, i.e., 222, which is sensitive to both TNF-alpha and DTX, 222TR, a TNF-alpha-resistant DTX-sensitive variant of 222, and SKOV-3, which is resistant to both DTX and TNF-alpha. The simultaneous use of DTX and TNF-alpha at suboptimal concentrations resulted in synergistic cytotoxic activity against all three lines tested, thus overcoming the TNF-alpha resistance of 222TR and the double resistance of SKOV-3. DNA fragmentation was observed in all three lines treated with DTX and TNF-alpha and occurred as early as 4 h after treatment. Cycloheximide, actinomycin D, or emetine, at concentrations causing greater than 90% protein synthesis inhibition, did not result in cytotoxicity alone or synergy with TNF-alpha, suggesting that synergy by DTX was not due to its ability to inhibit protein synthesis. The use of energy poisons and pH conditions that inhibit DTX-mediated cytotoxicity resulted in the abrogation of synergy. These findings show that the two cytotoxic agents TNF-alpha and DTX, when used at suboptimal concentrations, synergize in their cytotoxic activity against sensitive and resistant cell lines. Because the SKOV-3 cell line used here is also resistant to chemotherapeutic drugs, combination treatment with DTX and TNF-alpha may be beneficial in overcoming drug resistance.

Ammonium Chloride↗

PubMed1991

Oxygen equilibrium properties of highly purified human adult hemoglobin cross-linked between 82 beta 1 and 82 beta 2 lysyl residues by bis(3,5-dibromosalicyl) fumarate.

We investigated oxygen equilibrium properties of highly purified human adult hemoglobin cross-linked between lysine-82 beta 1 and lysine-82 beta 2 by a fumaryl group, which is prepared by reaction of the CO form with bis(3,5-dibromosalicyl) fumarate. The cross-linked hemoglobin preparation isolated by the previous purification method, namely, gel filtration in the presence of 1 M MgCl2 followed by ion-exchange chromatography, was found to be contaminated with about 20% of an electrophoretically silent impurity that shows remarkably high affinity for oxygen. This impurity was separated from the desired cross-linked hemoglobin by a newly developed purification method, which utilizes a difference between the authentic hemoglobin and the impurity in reactivity of the sulfhydryl groups of cysteine-93 beta toward N-ethylmaleimide under a deoxygenated condition. After this purification procedure, the oxygen equilibrium properties of purified cross-linked hemoglobin in the absence of organic phosphate became very similar to those of unmodified hemoglobin with respect to oxygen affinity, cooperativity, and the alkaline Bohr effect. The functional similarity between the cross-linked hemoglobin and unmodified hemoglobin allows us to utilize this cross-linking for preparing asymmetric hybrid hemoglobin tetramers, which are particularly useful as intermediately liganded models. Previous studies on this type of cross-linked hemoglobin should be subject to reexamination due to the considerable amount of the impurity.

Adult↗

PubMed1991

Tritium NMR spectroscopy of ligand binding to maltose-binding protein.

Tritium-labeled alpha- and beta-maltodextrins have been used to study their complexes with maltose-binding protein (MBP), a 40-kDa bacterial protein. Five substrates, from maltose to maltohexaose, were labeled at their reducing ends and their binding studied. Tritium NMR spectroscopy of the labeled sugars showed large upfield chemical shift changes upon binding and strong anomeric specificity. At 10 degrees C, MBP bound alpha-maltose with 2.7 +/- 0.5-fold higher affinity than beta-maltose, and, for longer maltodextrins, the ratio of affinities (KD beta/KD alpha) was even larger (between 10 and 30). The maximum chemical shift change was 2.2 ppm, suggesting that the reducing end of bound alpha-maltodextrin makes close contact with an aromatic residue in the MBP-binding site. Experiments with maltotriose (and longer maltodextrins) also revealed the presence of two bound beta-maltotriose resonances in rapid exchange. We interpret these two resonances as arising from two distinct sugar-protein complexes. In one complex, the beta-maltodextrin is bound by its reducing end, and, in the other complex, the beta-maltodextrin is bound by the middle glucose residue(s). This interpretation also suggests how MBP is able to bind both linear and circular maltodextrins.

ATP-Binding Cassette Transporters↗

PubMed1991

Site-directed mutagenesis in haemoglobin. Functional role of tyrosine-42(C7) alpha at the alpha 1-beta 2 interface.

To clarify the functional role of Tyr-42(C7) alpha, which forms a hydrogen bond with Asp-99(G1) beta at the alpha 1-beta 2 interface of human deoxyhaemoglobin, we engineered two artificial mutant haemoglobins (Hb), in which Tyr-42 alpha was replaced by Phe (Hb Phe-42 alpha) or His (Hb His-42 alpha), and investigated their oxygen binding properties together with structural consequences of the mutations by using various spectroscopic probes. Like most of the natural Asp-99 beta mutants, Hb Phe-42 alpha showed a markedly increased oxygen affinity, a reduced Bohr effect and diminished co-operativity. Structural probes such as ultraviolet-region derivative and oxy-minus-deoxy difference spectra, resonance Raman scattering and proton nuclear magnetic resonance spectra indicate that, in Hb Phe-42 alpha, the deoxy T quaternary structure is highly destabilized and the strain imposed on the Fe-N epsilon (proximal His) bond is released, stabilizing the oxy tertiary structure. In contrast with Hb Phe-42 alpha, Hb His-42 alpha showed an intermediately impaired function and only moderate destabilization of the T-state, which can be explained by the formation of a new, weak hydrogen bond between His-42 alpha and Asp-99 beta. Spectroscopic data were consistent with this assumption. The present study proves that the hydrogen bond between Tyr-42 alpha and Asp-99 beta plays a key role in stabilizing the deoxy T structure and consequently in co-operative oxygen binding.

Hemoglobins↗

PubMed1991

Effects of actinomycin D on airway constriction induced by tachykinins and capsaicin in guinea-pigs.

The effects of actinomycin D on airway constriction induced by tachykinins was studied in guinea-pigs in vitro and in vivo. Actinomycin D significantly inhibited the constriction of isolated guinea-pig trachea induced by neurokinin A (NKA) and eledoisin. Conversely, substance P (SP)- and physalaemine-induced constrictions were not affected by actinomycin D. The same selectivity in the inhibitory action of actinomycin D against tachykinins was also observed in in vivo. Actinomycin D given i.v. specifically inhibited the increase in airway resistance induced by NKA. I.v. injection of NKA caused not only airway constriction but also transient systemic hypotension. Interestingly, actinomycin D injected i.v. inhibited only airway constriction and the systemic hypotension induced by NKA was not affected. These results clearly suggest that actinomycin D specifically inhibits NKA-induced airway constriction in guinea-pigs. Actinomycin D also had an inhibitory action on the airway constriction induced by capsaicin. In the case of capsaicin-induced constriction, actinomycin D was more effective on the later phase of constriction than on the acute phase. The airway constriction induced by capsaicin is thought to be mediated by the release of SP and NKA from sensory nerve endings, and the persistent increase in airway resistance induced by capsaicin is thought to be due mainly to NKA.

Airway Resistance↗

PubMed1991

Significance of surgical adjuvant chemotherapy for gastric cancer.

One hundred and twenty-four specimens (72 primaries and 52 metastases) in 107 patients with gastric cancer were tested using the human tumor clonogenic assay (HTCA). Assays for 64 specimens (52%, 33 primaries and 31 metastases) were considered evaluable. The clonogenicity of the primaries was less than that of the metastases (P less than 0.01). In the primary specimens, well-differentiated tumors were more highly clonogenic than poorly differentiated or signet ring cell tumors (P less than 0.05). Viable malignant cells and clonogenic cells were abundant in the primary tumors with mucosal (m) and submucosal (sm) invasion, i.e., in early gastric cancers by Japanese criteria, and were reduced in numbers as the primary tumors advanced (P less than 0.05). In vitro chemosensitivity corresponded well to the clonogenicity of the primary tumors stratified by the degree of tumor invasion. At the early phase of primary tumor progression and metastasis, clonogenicity and chemosensitivity were high. Aggressive chemotherapy with sensitive drugs after surgery may improve the clinical results for the gastric cancer patients with early phase of metastases.

Adenocarcinoma↗

PubMed1991

Effects of splenectomy on pulmonary metastasis and growth of SC42 carcinoma transplanted into mouse liver.

The carcinoma SC42 was transplanted into the liver of its syngeneic mice DS, and the immunological integrity of the spleen and the effects of splenectomy on the growth and pulmonary metastasis of the liver tumor were assessed. On day 7 after liver tumor transplantation, the natural killer (NK) activity of the splenocytes was significantly elevated; it subsequently decreased at a later stage of the tumor. The response of the splenocytes to PHA and Con-A decreased significantly from the early stage of the tumor. However, the mixed lymphocyte-tumor cell reaction increased significantly from day 14 to day 28. The survival rate of the mice, which had undergone simultaneous splenectomy and liver tumor transplantation, was significantly lower than that of sham-operated control mice. The number of pulmonary metastases in splenectomized mice was significantly greater than in the control mice. There was, however, no difference between the two groups in the weight of the liver tumor. By contrast, splenectomies performed 14 days before or 14 days after tumor transplantation had no significant influence on the survival of the mice. Splenectomies performed on day 0 and on day 3 after tumor transplantation significantly increased the number of pulmonary metastases. Furthermore, the intravenous injection of anti-asialo GM1 antisera on day 0 and day 3 significantly increased the number of pulmonary metastases, but injection of anti-Thy 1.2 antisera had no effect. These results suggest that splenic NK cells may play an important role in the suppression of pulmonary metastasis at early stages of the liver tumor.

Animals↗

PubMed1991

A novel point mutation at codon 146 of the K-ras gene in a human colorectal cancer identified by the polymerase chain reaction.

In this report, point mutations of the K-ras gene at codon 146 were analyzed in 25 cases of colon cancer, 4 cases of lung cancer, and 41 cases of lymphoid malignancy. A codon 146 mutation substituting threonine (ACA) for alanine (GCA) was detected in the tumor tissue of a patient with colon cancer and was not detected in the normal tissue of the same patient. Any additional mutations of the ras gene family were not detected in this patient. These results suggest that the codon 146 mutation of the K-ras gene could be involved in the development of naturally occurring human malignancies.

Antisense Elements (Genetics)↗

PubMed1991

In vitro immunomodulating effect of protein-bound polysaccharide, PSK on peripheral blood, regional nodes, and spleen lymphocytes in patients with gastric cancer.

PSK, a protein-bound polysaccharide, has been widely used for cancer immunotherapy in Japan. However, the mechanism of its immunomodulatory effect has not been fully clarified. In the present study the in vitro effect of PSK on the lymphocytes of patients with gastric cancer was studied. Culturing lymphocytes with PSK at 5-100 micrograms/ml increased the level of DNA synthesis, and augmented the cytotoxicities against K562 and KATO-3. Flow-cytometric analysis also showed an increase in the proportion of interleukin-2 (IL-2)-receptor-positive cells after the lymphocytes were cultured with PSK. However the cytotoxicity of cells cultured with PSK was not augmented by the addition of recombinant interferon gamma (rIFN gamma) and rIL-2. Further experiments using fractionated PSK showed that its biological action is present mainly in fractions having molecular masses greater than 10(5) Da. However, these immunomodulations were not seen in all patients. These results suggest that the susceptibility of lymphocytes to PSK may be different in each patients, and that the immunomodulation by PSK may be mediated by mechanisms independent of IFN and IL-2.

Adjuvants, Immunologic↗

PubMed1991

In vivo effects of human recombinant tumor necrosis factor alone and in combination with other biological response modifiers on human digestive organ cancer xenografts transplanted in nude mice.

The present study was designed to evaluate the effect of rTNF alone or in combination with other BRMs on human digestive organ cancers. Six kinds of human digestive organ cancer xenografts (esophageal, stomach, colonic, pancreatic, bile duct, and liver cancers: EC-YO, GC-YN, CC-KK, PC-HN, BDC-SN and Li-7, respectively) were transplanted in nude mice, and rTNF was administered at 10(3), 5 x 10(3), or 10(4)U/head directly into the tumor 3 times a week for 2 weeks. EC-YO was the most sensitive to rTNF, and intratumoral administration of rTNF at 10(3) U/head caused tumor regression. PC-HN, CC-KK and GC-YN were relatively sensitive to rTNF, and their growth was significantly inhibited by rTNF at 5 x 10(3) U/head, however, the tumors regrew after treatment. Li-7 and BDC-SN were resistant to rTNF. The effects of rTNF in combination with recombinant interferon-gamma (rIFN-gamma), recombinant interleukin-2 (rIL-2), or streptococcal preparation OK-432 were assessed in mice transplanted with GC-YN. All combinations of rTNF at 5 x 10(3) U/head and other BRMs were more effective than rTNF alone, and GC-YN tumors were completely regressed after treatment with a combination of rTNF and rIFN-gamma or rTNF and OK-432. However in all cases, the combination of rTNF at 10(3) U/head and any other BRM did not improve the effect. Furthermore, the adverse effects of the combinations were more serious than those of rTNF alone. TNF may still be a useful cytokine, because it can induce the regression of tumors. However, for its clinical application, a method should be developed to reduce its side effects.

Animals↗

PubMed1991

Perforin expression in lymphocytes infiltrated to human colorectal cancer.

Perforin (PFP) is a cytotoxic protein released from killer cells. PFP immunoreactivity in human peripheral blood lymphocytes (PBL) and tumour infiltrating lymphocytes (TIL) was investigated immunocytochemically with the aid of an anti-PFP monoclonal antibody. PFP was detected in the cytoplasm of 10% of PBL. We performed a double staining of PFP+ cells with Leu11b/CD16, Leu2a/CD8, or Leu3a/CD4 and showed that PFP was produced by 9% of CD8+ cells and 18% of CD16+ cells but not by CD4+ cells. In 28 colorectal cancer tissues, PFP immunoreactivity was observed in the lymphocytes infiltrating to the tumour stroma. The PFP+ cells were most numerous in Dukes A and decreased in number according to the progression of tumours. The PFP+ cells in TIL exhibited the same phenotypes as those in PBL but the PFP+ cells were more numerous in CD8+ cells than in CD16+ cells at all stages. This study represents the first evidence that PFP is mainly secreted from CD8+ cells in tumour tissues. It is hypothesised that the decrease in the number of PFP+ cells in accordance with tumour progression may reflect the suppression of the hosts local immunity.

Antibodies, Monoclonal↗

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

Significance of postoperative early chemotherapy for locoregional lymph node metastases of gastric and colorectal cancer.

Eighty-seven locoregional lymph node metastatic specimens from 52 gastric cancers and 35 colorectal cancers were tested using a human tumor clonogenic assay and the results were analyzed. Experiments were considered evaluable in 31 gastric and 21 colorectal specimens, respectively. Metastatic malignant cells and clonogenic cells per gram of wet specimen were significantly more prevalent in smaller (1.5 g weight or less) involved nodes (p less than 0.005 and p less than 0.025, respectively). The clonogenicity was also higher in the smaller (2.0 g or less) specimens, although the difference was not significant. In vitro chemosensitivity was higher in the smaller nodes and this tendency corresponded well to the clonogenicity. The data showed that the clonogenicity and in vitro chemosensitivity were high in the early phase of locoregional lymph node metastasis, and suggested that perioperative chemotherapy could control lymph node micrometastases and prevent recurrence in patients with gastric or colorectal cancer.

Antineoplastic Agents↗

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↗