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Biomedical subjects

A Ito

Publications and source records attributed to A Ito.

At least 739 records · Page 41Linked to original sources
PubMed1987

Hymenolepis diminuta and H. nana: cross immunity against the lumen phase in BALB/c mice.

When BALB/c mice initially given cysticercoids of Hymenolepis diminuta orally (Day 0) were challenged with eggs or cysticercoids of H. nana, almost all the mice became completely resistant to H. nana challenges from Day 30 onward, and no luminal adults of H. nana were established. There was a tendency for the number of tissue cysticercoids recovered 4 days after egg challenge in immunized mice to be much less than that in control mice (P less than 0.001, Student's t test). However, when these cysticercoids recovered from immune group mice were inoculated into uninfected mice, they matured in the lumen. Thus, the cross immunity to H. nana challenge evoked by an initial prepatent infection with H. diminuta appeared to be directed not against the tissue phase but against the lumen phase of H. nana. When BALB/c mice initially given eggs of H. nana were challenged with H. diminuta, they became resistant to H. diminuta from Day 15 onward. When the mice given eggs of H. nana were treated with a cestocide, praziquantel, at the beginning of the expected luminal development of H. nana and experienced a tissue phase only before challenge with H. diminuta, they showed no resistance to H. diminuta. Thus, the cross immunity to H. diminuta challenge evoked by an initial patent infection with H. nana appeared to be due to the immunogens of the lumen phase of H. nana but not those of the tissue phase. The cross immunity may be, therefore, essentially evoked by the lumen phase of these two phylogenetically closely related species and not by or against the tissue phase of H. nana.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Mutagen detection with a mouse line containing 3 distinct mutations conferring sensitivity.

A mouse-cell mutant sensitive to methyl methanesulfonate (MMS), X-rays, ultraviolet light (UV), and crosslinking agents was selected using the replica plating and cell suspension spotting methods. This mutant (XUM1) is a mitomycin C-sensitive derivative of previously reported XU1, a mutant sensitive to MMS, X-rays and UV. Since XU1 is highly susceptible to the lethal effect of 4-nitroquinoline-1-oxide (4NQO), XUM1 is also hypersensitive to 4NQO. Growth inhibition area tests showed that low concentrations of mutagens were detected with the multiple mutagen-sensitive mutant XUM1. Hence XUM1 cells will be useful in detecting with high sensitivity a wide range of mutagens and carcinogens which mimic X-rays, UV and crosslinking agents.

4-Nitroquinoline-1-oxide↗
PubMed1987

Kallikrein in synovial fluid with rheumatoid arthritis.

The levels of kallikrein and collagenase in synovial fluid from rheumatoid arthritis (RA) patients were examined and the role of kallikrein in procollagenase activation is discussed. Both prekallikrein and active kallikrein in synovial fluid from patients with RA were significantly elevated when compared to synovial fluid from patients with osteoarthritis (OA). In RA synovial fluid, the ratio of the active form to total kallikrein was also higher than that in OA synovial fluid. Both active collagenase and the alpha 2-macroglobulin (alpha 2M)-collagenase complex in RA synovial fluid were higher than in OA synovial fluid. A partial correlation (r = 0.58) between active kallikrein and total collagenase (active and alpha 2M-collagenase complex) was observed in RA synovial fluid. These observations indicate that both kallikrein and collagenase are associated with the destruction of cartilage, but the role of kallikrein in procollagenase activation was not fully clarified.

Adult↗
PubMed1987

Comparison of the inactivation of Bacillus subtilis transforming DNA by the potassium superoxide and xanthine-xanthine oxidase systems for generating superoxide.

Potassium superoxide (KO2) and xanthine-xanthine oxidase (X-XO), which are known generating systems for the superoxide anion, have different inactivating actions on Bacillus subtilis transforming DNA in vitro. Superoxide dismutase and CuSO4 enhanced the inactivation for KO2, but not for X-XO. Mannitol, a hydroxyl radical scavenger, protected against the inactivation by X-XO, but not by KO2. The results obtained with X-XO were consistent with the involvement of Fenton reactions, in which hydroxyl radical is the reactive species that ultimately causes damage. On the other hand, KO2-induced inactivation was partly due to the effect of H2O2. Differences in inactivation between the KO2 and X-XO systems may result from the different rates of production of the superoxide anion.

Bacillus subtilis↗
PubMed1987

Cortisone-sensitive, innate resistance to Hymenolepis nana infection in congenitally athymic nude rats.

The innate resistance of the unnatural rat host to the mouse tapeworm Hymenolepis nana is cortisone sensitive but thymus independent. When congenitally athymic nude rats were orally given eggs, cysticercoids, or adult worms of H. nana, no lumenal adults were established except when they were treated with cortisone acetate during the expected lumenal development. The effect of cortisone to promote adult maturation in the rats was compared in nude and normal rats given eggs of H. nana. The fecundity of the worms (assessed by the fresh worm biomass and the number of infective eggs produced) was much higher in cortisone-treated nude rats than in cortisone-treated normal rats. When the nude rats reconstituted with thymocytes were given eggs and treated with cortisone, the fecundity of H. nana dropped to the same level as in cortisone-treated normal rats. It is strongly suggested that the unnatural rat host has thymus-independent cortisone sensitive resistance to an initial infection (which is the main component of the innate resistance and blocks the lumenal establishment of this parasite) and thymus-dependent resistance (which suppresses the established worms' fecundity and may be ascribed to acquired resistance to the ongoing infection).

Animals↗
PubMed1987

Changes in surface antigens of Hymenolepis nana during differentiation and maturation in mice.

The surface antigens of oncosphere, cysticercoid, adult scolex and adult strobila (other than scolex) of Hymenolepis nana differ critically from one another. When the oncosphere of H. nana undergoes differentiation and development into the mature tapeworm, the infected mouse first produces anti-oncosphere antibody, followed by anti-cysticercoid, anti-adult scolex and finally anti-strobila (other than scolex region) antibodies of IgG, IgM and IgA isotypes as detected by indirect immunofluorescent antibody test. The parasite changed its surface antigens throughout its differentiation and maturation, and all developmental stages were recognized by the infected mouse host. However, there appeared no further changes in surface antigens during aging after maturation. The antibody responses were always delayed compared with the differentiation and maturation of the parasite.

Animals↗
PubMed1987

Synthetic partial extension peptides of P-450(SCC) and adrenodoxin precursors: effects on the import of mitochondrial enzyme precursors.

Various portions of the extension peptides of P-450(SCC) precursor were chemically synthesized. The effects of these peptides on the import of enzyme precursors into mitochondria were examined. Peptides SEP1-15 and SEP1-20, corresponding to the amino terminal portion of the extension peptides, strongly inhibited the import of P-450(SCC) precursor into mitochondria. These peptides were effective at concentrations above 30 microM, and complete inhibition was observed at 100 microM. SEP1-11, which is shorter than SEP1-15 and SEP1-20, showed very weak inhibition. SEP25-39, which corresponds to the carboxy terminal portion of the extension peptide, did not affect the import of the precursor. The import of P-450(11 beta) and adrenodoxin precursors were also inhibited by SEP1-15. Another peptide, AEP1-14, which corresponds to the amino terminal portion of the extension peptide of adrenodoxin precursor, was also synthesized. The peptide inhibited the import of both adrenodoxin and P-450(SCC) precursors into mitochondria. The import of malate dehydrogenase was also inhibited by SEP1-15 and AEP1-14. The rate of the internalization of the precursor into mitochondria was decreased by the peptides. The amount of the precursor bound to the surface of mitochondria and the processing of adrenodoxin precursor were not affected. The respiratory activities of isolated mitochondria were not influenced by SEP1-15 even at 100 microM. We conclude that the inhibitory activities of the synthetic partial extension peptides on the import of enzyme precursors into mitochondria require the presence of about fifteen amino acid residues in the amino terminal portion of the extension peptides, and the inhibition of the import by the peptides was dependent on the blockage of the internalization of the precursors into mitochondria.

Adrenodoxin↗
PubMed1987

Site-directed mutagenesis of basic amino acid residues in the extension peptide of P-450(SCC) precursor: effects on the import of the precursor into mitochondria.

The precursor of cytochrome P-450(SCC) (preP-450(SCC], an inner membrane protein of adrenal cortex mitochondria, has an extension peptide consisting of 39 amino acids which is thought to play an essential role in the import of the precursor into mitochondria. The amino terminal portion of the extension peptide contains three positively charged amino acid residues, Arg(4), Arg(9), and Lys(14). To investigate their role in the import of preP-450(SCC) into mitochondria, they were replaced by other amino acids, Ser or Thr, by site-directed mutagenesis. The import of mutated preP-450(SCC)s with single amino acid substitution was much less efficient than with the original precursor. The mutated preP-450(SCC)s with two or three substitutions were not imported. These results suggest that the positively charged amino acid residues in the amino terminal portion of the extension peptide are essential for the import of preP-450(SCC) into mitochondria.

Amino Acids↗
PubMed1987

Dehydroepiandrosterone sulfate stimulates collagenase synthesis without affecting the rates of collagen and noncollagen protein syntheses by rabbit uterine cervical fibroblasts.

The effects of dehydroepiandrosterone 3-sulfate (DHAS) and 17 beta-estradiol (E2) on collagen and noncollagen protein syntheses by rabbit uterine cervical cells were studied, and their effects on latent collagenase synthesis were compared. DHAS (1 X 10(-6) M) stimulated the synthesis of latent collagenase and did not affect the cell number and [3H]thymidine incorporation into DNA, whereas E2 had no effect on collagenase synthesis. On the other hand, neither DHAS (1 X 10(-6) M) nor E2 (1 X 10(-10)-1 X 10(-6) M) showed effects on collagen and noncollagen protein syntheses. These results suggest that the stimulative effect of DHAS on cervical ripening is mediated mainly by the stimulation of collagen catabolism, and that E2 does not concern the changes in the concentration of collagen and noncollagen protein in uterine cervix of the rabbit during pregnancy at term.

Animals↗
PubMed1987

The role of leukocyte factors on uterine cervical ripening and dilation.

To clarify the role of leukocytes effused into uterine cervix at term pregnancy, the effect of conditioned medium (MCM) of rabbit peritoneal macrophages on the production of specific collagenase by cervical cells was investigated, in vitro. MCM stimulated uterine cervical cells to induce a 10-fold increase in collagenase production as compared with the control. Similarly, production of gelatinolytic metalloproteinase (an endogenous procollagenase activator) increased to about 4-fold of the control cultures, whereas MCM did not affect [3H]thymidine incorporation into DNA. The enhancement of collagenase production was depressed by the treatment of cells with 10(-6) M cycloheximide. The MCM also contained lymphocyte-activating activity (interleukin-1). These data suggest that rabbit uterine cervical cells are able to produce both specific collagenase and gelatinolytic metalloproteinase in response to interleukin-1, and that leukocytes effused into the cervix may participate in the ripening and dilation of uterine cervix at term pregnancy.

Animals↗
PubMed1987

Effect of monoclonal antibody to pertussis toxin on toxin activity.

Two distinct monoclonal antibodies, one to pertussis toxin subunit S2, called 9G8, and another to subunits S2 and S3, called 11E6, were generated from the hybridomas of myeloma SP2/0 and spleen cells of BALB/c mice immunized mainly with the subunit S234 complex. Binding ability of 9G8 and 11E6 to the subunits was confirmed by the enzyme-linked immunosorbent assay and immunoblotting analysis. Generation of 11E6 bound to both S2 and S3 might mean that there is common antigenicity between S2 and S3. Neutralizing activities of 9G8 and 11E6 on various biological activities of pertussis toxin, including ADP-ribosyltransferase and leukocytosis-promoting, islet-activating, permeability-increasing. Chinese hamster ovary (CHO) cell-clustering, and hemagglutinating activities, were compared with those of anti-S1 monoclonal antibodies 1B7 and 3F10, which were isolated and characterized in a previous study (H. Sato, A. Ito, J. Chiba, and Y. Sato, Infect. Immun. 46:422-428, 1984). 1B7 and 3F10 neutralized ADP-ribosyltransferase activity of pertussis toxin or S1, but 9G8 and 11E6 did not. 1B7 showed very potent neutralization against leukocytosis-promoting, islet-activating, permeability-increasing, and CHO cell-clustering activities of pertussis toxin, but 3F10 did not, although anti-ADP-ribosyltransferase activities of both antibodies were identical. 11E6 neutralized leukocytosis-promoting, islet-activating, CHO cell-clustering, and hemagglutinating activities but not permeability-increasing activity. 9G8 showed slight neutralization of leukocytosis-promoting and CHO cell-clustering activities. Specific activities of 1B7 and 11E6 in each neutralization test were higher than or almost comparable to those of polyclonal antibodies to pertussis toxin. The neutralizing mechanism of 1B7 and 11E6 in leukocytosis-promoting activity was compared. 11E6 seemed to interfere with the binding of pertussis toxin to receptors on mouse spleen cells.

Animals↗
PubMed1987

Optimum conditions for electric pulse-mediated gene transfer to mammalian cells in suspension.

A pulse-generating machine which delivers exponentially decaying pulses over broad range of pulse lengths was used to determine the optimum pulse conditions for gene transfer to FM3A cells. In the transformation of tk- cells with pTK1, a single pulse of 100-2000 microseconds gave a high transformation frequency at 1.5-6 kV/cm and room temperature, the highest transformation frequency obtained being 3 X 10(-3). As the suspension buffer for cells exposed to the pulse, Saline G was better than PBS(-) for obtaining a large number of transformants because it ensured high cell viability.

Animals↗
PubMed1987

Periarteritis nodosa in rats treated with chronic excess sodium chloride (NaCl) after X-irradiation.

Five-week-old male Crj:CD (SD) rats were treated with excess sodium chloride after abdominal X-irradiation. The gastric regions of the rats were irradiated with a total dose of 20 Gy given in two equal fractions separated by 3 days. After X-irradiation, animals were fed a diet containing 10% sodium chloride. Red blood cell anemia appeared 22 weeks after the last irradiation. By gross observation, the mesenteric arteries became reddish in color, and bead- or lead pipe-like nodular thickenings were present. Microscopically, these nodularly thickened mesenteric arteries showed fibrinoid necrosis with massive inflammatory infiltration including eosinophils and neutrophils. In more advanced lesions, elastica interna and externa and medial smooth muscle cells disappeared completely and were replaced by granulation tissue. In old lesions, arterial walls were markedly thickened with fibrous or fibromuscular tissue. These findings were quite similar to those of the human periarteritis nodosa. These arterial lesions could not be found in the rats with X-irradiation only, sodium chloride only, or in nontreated animals. This study demonstrates X-ray-induced, NaCl-promoted periarteritis nodosa-like lesions in rats.

Animals↗
PubMed1987

Induction of gastric tumor and intestinal metaplasia in rats exposed to localized X-irradiation of the gastric region.

The induction of gastric tumor and intestinal metaplasia was examined in 8-week-old male JCL/SD rats exposed to localized X-irradiation of the gastric region. The animals were each given two 20 Gy fractions of X-rays, with a one-week interval between fractions (total, 40 Gy). Nine atypical hyperplasias (20%) and 13 adenocarcinomas (28%) in the pyloric mucosa of the glandular stomach were found in 46 animals with X-irradiation. The incidence of intestinal metaplasia was 93% in the pyloric mucosa, 50% in the fundic mucosa and 96% in both the pyloric and fundic mucosa. Type B metaplasia (intestinal metaplasia without Paneth cells) was most common and type C (intestinal metaplasia with Paneth cells) was less frequent. No gastric tumor or intestinal metaplasia appeared in non-irradiated control rats. This study shows that local X-irradiation of the gastric region induced both gastric tumor and intestinal metaplasia independently.

Animals↗