Biomedical subjects

T Hongyo

Publications and source records attributed to T Hongyo.

27 records · Page 2Linked to original sources

PubMed1994

[Effect of mesalazine microgranules on experimental colitis].

Mesalazine microgranules are an ethylcellulose-coated formulation from which mesalazine is released throughout the intestinal tract and are expected to be effective for idiopathic inflammatory bowel disease, ulcerative colitis and Crohn's disease. Mesalazine microgranules were administered orally to investigate the distribution of mesalazine throughout the intestinal tract in rats. Mesalazine microgranules distributed sufficient amounts of mesalazine and its metabolite, N-acetyl-mesalazine, to the intestinal tissues, while pure mesalazine delivered lower amounts of both. In acetic acid-induced colitis in rats, mesalazine microgranules administered orally reduced the damage score significantly (P < 0.05) at a dose of 50 mg/kg as assessed by macroscopic observation and at 100 mg/kg as assessed by histological evaluation. The number of ulcers in carrageenan-induced colitis in guinea pigs was inhibited at doses of 50, 100, 200 mg/kg, p.o. The colonic wet weight of rats in 2,4,6-trinitrobenzenesulfonic acid (TNB)-induced colitis was reduced significantly (P < 0.05) at a dose of 50 mg/kg, p.o. Mesalazine microgranules showed the ability to distribute mesalazine efficiently throughout the intestinal tract and showed effectiveness against acetic acid-, carrageenan- and TNB-induced colitis. These studies strongly suggest that mesalazine microgranules are effective for idiopathic inflammatory bowel disease.

Aminosalicylic Acids↗

PubMed1993

'Cold SSCP': a simple, rapid and non-radioactive method for optimized single-strand conformation polymorphism analyses.

A rapid (< 2.5 hrs) method for single-strand conformation polymorphism (SSCP) analysis of PCR products that allows the use of ethidium bromide staining is described. PCR products ranging in size from 117 to 256 bp were evaluated for point mutations and polymorphisms by 'cold SSCP' in commercially available pre-cast polyacrylamide mini-gels. Several electrophoretic parameters (running temperature, buffers, denaturants, DNA concentration, and gel polyacrylamide concentration) were found to influence the degree of strand separation and appeared to be PCR fragment specific. Use of the 'cold' SSCP technique and the mini-gel format allowed us to readily optimize the electrophoretic conditions for each PCR fragment. This greatly increased our ability to detect polymorphisms compared to conventional, radioisotope-labeled 'hot' SSCP, typically run under two standard temperature conditions. Excellent results have been obtained in resolving mutant PCR fragments from human p53 exons 5 through 8, human HLA-DQA, human K-ras exons 1 and 2, and rat K-ras exon 3. Polymorphisms could be detected when mutant DNA comprised as little as 3% of the total gene copies in a PCR mixture. Compared to standard 'hot' SSCP, this novel non-isotopic method has additional advantages of dramatically increased speed, precise temperature control, reproducibility, and easily and inexpensively obtainable reagents and equipment. This new method also lacks the safety and hazardous waste management concerns associated with radioactive methods.

Animals↗

PubMed1993

Reduction of leaky lymphocyte clones producing immunoglobulins and thymic lymphocytic leukemia by selective inbreeding of SCID (severe combined immunodeficiency) mice.

Selective inbreeding of C.B17-scid/scid mouse pairs showing undetectable IgG and IgM has been carried out in order to reduce the mortality of mice by early occurrence of thymic lymphocytic leukemia and abnormal lymphocyte clones producing immunoglobulins, both of which inhibit the successful heterotransplantation of normal and neoplastic human tissues. Although the majority of C.B17-scid/scid mice showed undetectable (< 1 microgram/ml) or low level (< or = 25 micrograms/ml) of serum IgG and IgM, some produced abnormally high concentrations of IgG and IgM (> 25 micrograms/ml). The incidence of such mice showing higher levels of IgG was very high at F1 and F2 generation (10/55, 18.2%), but significantly low after the F3 generation (18/446, 4.0%, p << 0.001). Although leukemia incidence was very high at F4 to F5 generations (8/40, 20.0%), death from leukemia was not observed early in life (4-6 months after birth) at F7 to F10 generations (0/36, 0%, p < 0.01) and was very low during the age of 6-10 months after the F8 generation (11/66, 16.7% at F4 and F5 vs 4/93, 4.3% at F8-10), p < 0.01). Scid mice improved by the selective inbreeding will provide an invaluable experimental system for the heterotransplantation of normal and neoplastic human tissues.

Animals↗

PubMed1992

Programmed cell death in whole body and organ systems by low dose radiation.

New whole-body and organ systems were established to detect interphase cell death in the thymus, spleen and epithelial cells of intestinal crypts by low-dose radiation. Frozen sections of the thymus, spleen and intestine as thick as 8 microns were made after X-irradiation of whole body or removed organs, and then sections were stained with 0.02% erythrosin B solution. In unirradiated controls, a few numbers of erythrosin B positive cells (dead or dying cells) were observed in the thymus, spleen and intestinal crypt as a single cell death. When X rays were given to various strains of mice as a whole body dose, clusters of erythrosin B positive cells were produced. They appear at 2 hr after irradiation and reached maximum at 4 hr, remaining at a similar level until 8 hr after irradiation. The number of erythrosin B positive cells decreased after then by the elimination of dead cells, and they were observed like a single cell death at 24 hr after irradiation. When erythrosin B positive cells were scored 4 hr after irradiation, their total number and the number of cluster increased with increasing doses of X rays in the dose range from 0.05 to 0.5 Gy. It is noted that there were large differences in the radiation susceptibility among the inbred strains of mice for the induction of interphase cell death of thymic lymphocytes: e.g., high susceptibility in C57BL/6J and AKR/J, intermediate in N4, A/J, PT and ST, low in C3H/HeJ, HT, 101/H and DBA/2J, indicating that interphase cell death is genetically programmed. Similar results were observed with some chemical mutagens. Although a large increase of erythrosin B positive cells was observed in the thymus and spleen with methylprednisolone, there was no increase in the intestinal crypt, and vice versa with bleomycin, suggesting the organ specificity for the induction of interphase cell death by chemicals. For the in vitro method, the removed thymus was irradiated on the agar plate, and then incubated on the agar plate which was placed on the grid in the medium, so that the medium comes up to the organ through the agar plate. Frozen sections were made and stained with erythrosin B solution in the same way as the in vivo method. The number of erythrosin B positive cells in the organ culture system reached maximum at 5 hr after X-irradiation, e.g. slightly later than in the whole-body system. The efficiency was about 60% in C57BL/6J mice when compared with whole-body system.

Animals↗

PubMed1991

Inhibition of growth and pulmonary metastasis of B16-F10 murine melanoma by N-1554, a polyprenyl phosphate.

Antitumor effect of N-1554 (alpha-dihydrodecaprenyl phosphate containing eight trans internal isoprene residues) against B16-F10 melanoma in syngeneic C57BL/6 mice was examined. B16-F10 cells were inoculated into the footpad of mice and N-1554 was intraperitoneally administered after the inoculation. The drug significantly inhibited the tumor growth in the footpad and dramatically reduced the pulmonary metastasis from the tumor. The antitumor effect of N-1554 was almost abolished when the immunosuppressant carrageenan or anti-asialo GM1 antibody was administered to mice. In addition, pretreatment of host mice with N-1554 reduced the growth of subcutaneously inoculated B16-F10 melanoma. These results suggest that enhancement of host immune system may be involved in the antitumor effect of N-1554.

Animals↗

PubMed1991

Rapid growth and spontaneous metastasis of human germinal tumors ectopically transplanted into scid (severe combined immunodeficiency) and scid-nudestreaker mice.

Xenograft acceptance, growth and spontaneous metastasis of ectopically transplanted human germinal tumors were compared among scid mice, athymic nude mice and F2 hybrids constructed from scid and nude mice, in relation to the impairments of T and B cell functions in these mice. In scid mice which are deficient in T and B cell functions, human yolk sac tumor (YST-2) that originated from the ovary grew to enormous sizes in 100% of the animals after both subcutaneous and intraperitoneal transplantation, while only half (59.1% and 51.9%) of the subcutaneous and none of the intraperitoneal transplants were accepted in usual athymic nude mice (BALB/c-nu/nu and CD1-nu/nu). The YST-2 grew rapidly in scid mice, developing 3 to 10 times larger tumors compared to nude-streaker (AKR/J-nustr/nustr) and usual nude mice, respectively. Furthermore, ectopically transplanted tumors spontaneously metastasized to distant organs (mostly to the lung) in scid mice (but less frequently in leaky scid mice), while metastases have never been found in nude mice. Although a xenograft of human classic (typical or pure) seminoma of the testis has never been established in nude mice, it grows slowly in one-third (36.4%) of scid mice and very rapidly in all of scid-nustr (scid/scid; nustr/nustr) double mutant mice. Spontaneous metastases of xenografted seminomas were also observed in distant organs (lymph node, lung, liver, spleen, and kidney). The metastastic distribution of the two human germinal tumors in scid and scid-nustr mice mimics that found in human. These results (xenograft acceptance, growth of transplanted tumors and degree of metastatic spread) were compatible with the level of T and B cell impairments indicated by FACS analysis, as well as mitogen responses, serum IgG and morphological features of the thymus.

Animals↗

PubMed1990

Embryonic mutation as a possible cause of in utero carcinogenesis in mice revealed by postnatal treatment with 12-O-tetradecanoylphorbol-13-acetate.

Although in utero irradiation at early stages induced a high incidence of somatic mutations at coat color genes in the embryos of a specified tester strain (PT x HT F1) of mice, it was not carcinogenic by itself. However, in utero-irradiated animals did develop skin tumors and hepatomas (but not leukemias) by the postnatal administration of 12-O-tetradecanoylphorbol-13-acetate. The incidence of both tumors and embryonic mutations increased with in utero doses of X-rays. Furthermore, a large reduction of tumor incidence, about 80%, was observed by low-dose-rate irradiation, similar to the 75% reduction in spot size found for embryonic mutations. The tumor nodule size was also dramatically reduced by low-dose-rate irradiation. Consequently, the induced incidence and size of tumors produced by 12-O-tetradecanoylphorbol-13-acetate treatment parallel those which are observed for coat color mutations as expected, because somatic mutations observed in the pigment cells must similarly occur in embryonic cells of other organs. The larger the clone of mutant cells, the greater their chance of becoming tumorigenic by 12-O-tetradecanoylphorbol-13-acetate posttreatment. These results strongly support the recent epidemiological survey showing that adult types of cancers, but not leukemias, are increasing in the atomic bomb survivors exposed in utero, since humans are continuously exposed to a variety of cancer-promoting agents in contrast to experimental animals reared without such exposures.

Animals↗

PubMed1990

SCID (severe combined immunodeficiency) mice as a new system to investigate metastasis of human tumors.

In severe combined immunodeficiency (scid) mice which are deficient in T and B cell functions, human yolk sac tumor (YST-2) grew rapidly to enormous sizes in all of the animals after both subcutaneous and intraperitoneal transplantation, while only half of the subcutaneous and none of the intraperitoneal transplants were accepted in usual athymic nude mice. Furthermore, transplanted tumors metastasized spontaneously to distant organs such as lung, liver, kidney, pancreas, and spleen in scid mice, while metastases were not found in athymic nude mice. Similar results were observed in scid mice and scid-nude (streaker) double mutant mice with human classic (typical) seminoma which has been neither transplantable nor metastatic in athymic nude mice. Thus, scid mice provide an invaluable experimental system to investigate the mechanism of metastasis which is the most important and life-threatening problem in cancer patients.

Animals↗

PubMed1987

[A case of double neoplasms--small cell carcinoma in the mediastinum and squamous cell carcinoma of the esophagus].

A 62-year-old Chinese man was admitted to our hospital because of dysphagia and hoarseness. Chest X-rays showed a superior mediastinal mass, and an operation for the removal of this mediastinal tumor was performed. The histological diagnosis indicated a small cell carcinoma, probably arising from the lung. He was readmitted to our clinic one year later with a complaint of dysphagia due to an esophageal cancer. Radical surgery for the esophageal cancer was performed, and the histological findings showed a well differentiated squamous cell carcinoma. The histogenesis of this carcinoma was considered to be independent of the earlier mediastinal tumor.

Adenocarcinoma↗