Search PubMed⌕ Search

Biomedical subjects

A Ito

Publications and source records attributed to A Ito.

At least 667 records · Page 37Linked to original sources
PubMed1989

Antitumor effect of a baker's yeast mannan-mitomycin C conjugate against mouse hepatoma, MH134, in vivo and in vitro.

A conjugate of mitomycin C and the mannan of bakers' yeast (Saccharomyces cerevisiae wild type strain) was synthesized. Assay of its growth inhibitory effect on MH134 hepatoma solid tumor implanted in C3H/He slc mice showed that this conjugate exhibited a higher growth-inhibition ratio than those of free mitomycin C and the same bakers' yeast mannan in the corresponding effective doses. This conjugate was also found to kill the same hepatoma cells in vitro. Because a dextran-mitomycin C conjugate did not manifest any antitumor effect against this tumor, it was postulated that interaction of the mannan moiety in the mannan-mitomycin C conjugate with the mannose receptor located on the cell surface of immunocytes and/or with hepatoma cells participated in the common initiating reaction of in vitro and in vivo antitumor effects.

Animals↗
PubMed1989

Immunocytochemical localization of the beta I subspecies of protein kinase C in rat brain.

Polyclonal antibodies were raised against an oligopeptide containing an amino acid sequence specific for beta I protein kinase C (PKC) in order to localize this subspecies of PKC in the rat brain. beta I PKC immunoreactivity was widely distributed but discretely localized in particular brain regions. The immunoreactivity was associated with neurons but not glial cells and was generally weak in the neutrophils with the exception of areas such as the triangular septal nucleus, pontine nuclei, superficial layer of the superior colliculus, and gray matter of the spinal cord. The largest number of beta I PKC-immunoreactive cells was seen in the triangular septal nucleus and pontine nuclei. In these areas of dense beta I immunoreactivity, there was no or little gamma PKC immunoreactivity. The beta I PKC immunoreactivity was observed in perikarya, dendrites, and axons but not in nuclei or nucleoli. There were various patterns of cytoplasmic immunoreactivity, but the immunoreactivity was seen frequently in the periphery of the perikarya and dendrites. The intraneuronal localization of beta I PKC immunoreactivity differs from that of the subspecies that is coded by the gamma gene sequence. The results suggest that beta I PKC may play a role in the regulation of cell membrane responsiveness in particular neurons.

Animals↗
PubMed1989

Immunocytochemical localization of beta II subspecies of protein kinase C in rat brain.

The distribution of a subspecies of protein kinase C (PKC) encoded by the beta II sequence in rat central nervous tissue was demonstrated immunocytochemically by using antibodies raised against an oligopeptide having a partial sequence specific for the beta II PKC. The beta II PKC immunoreactivity was widely but discretely distributed in the brain. The distribution of the beta II PKC immunoreactivity differed from that of the beta I and gamma PKC subspecies. The beta II PKC immunoreactivity was found in the perikarya, dendrites, and axons of neuronal cells. Few if any glial cells were stained. Immunoreactive neurons were present in the anterior olfactory nucleus, olfactory tubercle, amygdaloid complex, caudate-putamen, accumbens nucleus, claustrum, dorsal part of the lateral septal nucleus, CA1 region of the hippocampus, subiculum, medial habenular nucleus, cerebral cortex, nucleus of the spinal tract of the trigeminal nerve, nucleus of the solitary tract, and substantia gelatinosa of the spinal cord. In these neurons, the beta II PKC immunoreactivity was seen mainly in the form of cytoplasmic dots and, in some cases, diffusely in the cytoplasm. Under electron microscopy, these immunoreactive large dots appeared to be associated with the Golgi complex, suggesting that the beta II PKC plays a specialized function at the Golgi complex in certain neuronal cell types.

Animals↗
PubMed1989

Effects of sex difference, gonadectomy and estradiol on N-ethyl-N-nitrosourea-induced trigeminal nerve tumors in rats.

The occurrence of trigeminal nerve tumors (TNTs) induced by neonatal administration of N-ethyl-N-nitrosourea (ENU) in WF x LE F1 (F1) rats was studied with special reference to sex difference, effect of gonadectomy and estradiol (E2) administration. Experimental groups 1-6 were treated with 40 mg ENU/kg of body weight neonatally. They consisted of male, female, castrated male, ovariectomized female, E2 pellet (0.1 mg, s.c.) supplemented and gonadectomized male and female rats respectively. Rats of groups 7-12 served as the respective controls without ENU. All the rats were killed at 8 months of age. Levels of serum E2 and E2 receptor (ER) of the TNTs were also examined. It was noted that the incidence of TNT was higher in males (79%) than in females (48%, P less than 0.05) and did not change by castration in males (91%) but increased in ovariectomized female rats (74%, P less than 0.05). Administration of E2 followed by gonadectomy inhibited the occurrence of TNTs in male rats (59%) but not in female rats (60%). No TNT was observed in any control groups. Kidney tumors were the second most frequent tumors next to nervous system tumors in the present experiment. The incidence of kidney tumors was much higher in females (38%) than in males (4%, P less than 0.05) and decreased by ovariectomy, whereas it increased in male rats by E2 administration. ER levels of TNTs and trigeminal nerve tissue were less than 1 fmol/mg protein. These results suggest that in rats treated with ENU neonatally, E2 has an inhibitory effect on the induction of TNTs but may not be regulated through ER. E2 also shows a promoting effect on kidney tumorigenesis.

Animals↗
PubMed1989

Critical region in the extension peptide for the import of cytochrome P-450(SCC) precursor into mitochondria.

In order to establish the role of the extension peptide of the precursor of P-450(SCC), a mitochondrial inner membrane protein, in the import into the organella, three deletion mutants of the precursor, in which the deletions were in the mature portion, were constructed. These mutant precursors were imported into mitochondria in vitro as efficiently as the original precursor, indicating that the extension peptide contains sufficient information for the import of the precursor into mitochondria. To investigate which portion of the extension peptide contains the mitochondrial targeting signal, various lengths of the amino-terminal portion of the extension peptide of P-450(SCC) precursor were fused to the mature portion of adrenodoxin. The fusion proteins consisting of 44 and 19 amino-terminal amino acids and mature adrenodoxin were imported into mitochondria, whereas those containing 14, 7, and 2 amino-terminal amino acid residues were not. The importance of the amino-terminal portion of the extension peptide was confirmed by the deletion from the amino-terminal end of a fusion protein consisting of the amino-terminal 44 amino acid residues of P-450(SCC) precursor and mature adrenodoxin, SCC44RAd. The amino-terminal deletions abolished the import of the fusion proteins into mitochondria. Substitution of all of the three basic amino acids, Arg(4), Arg(9), and Lys(14) in the extension peptide of SCC44RAd to Ser or Thr inhibited the binding of the fusion protein to mitochondria as well as its import.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenodoxin↗
PubMed1989

Induction of uterine hemangioendothelioma and lymphoma in (C57BL/6N x C3H/2N)F1 mice by oral administration of azathioprine.

The tumorigenicity of 6-(1-methyl-4-nitro-5-imidazolyl)mercaptopurine (azathioprine), an immunosuppressant, was examined in (C57BL/6N X C3H/2N)F1 mice. Animals were divided into 6 groups with 50 mice in each group, and they were given powdered diet mixed with 0, 5 or 20 ppm azathioprine starting at 6 weeks and ending at 100 weeks of age. Female mice, given 20 ppm azathioprine, developed lymphomas and uterine hemangioendotheliomas at incidences of 12.5 and 14.6%, respectively, which were significantly higher than the incidences in control mice (P less than 0.05). Lymphoma and uterine hemangioendothelioma developed independently in different mice. On the other hand, the male mice given 20 ppm azathioprine had a significantly (P less than 0.05) lower incidence of hepatic tumor (0.5%) compared to the control mice (16%).

Administration, Oral↗
PubMed1989

Stage-specific antigens of Hymenolepsis microstoma recognized in BALB/c mice.

Antigenicity of eggs (oncospheres), cysticercoids and adults (with immature segments only) of the bile duct tapeworm Hymenolepsis microstoma was analysed using immunoblotting techniques and indirect immunofluorescent antibody (IFA) techniques with immune sera of BALB/c mice (i) infected with different doses of cysticercoids, (ii) during patent or prepatent infection with the lumen phase of the parasite or (iii) sensitized with live or dead eggs. Antibody responses detected by IFA test and immunoblotting showed that antigenicity of eggs (oncospheres) differed from that of cysticercoids and adults. Single worm infections were sufficient to stimulate antibody responses. Mice which had patent infection showed strong antibody responses to all three (egg (oncosphere), cysticercoid, adult) antigens, while mice given two prepatent infections showed some antibody responses to cysticercoid and adult antigens only. Although the normal intermediate hosts of this parasite are arthropods, antibodies to some major egg (oncosphere) antigens were produced in mice given eggs of this parasite orally, either through inoculation of eggs or ingestion of faeces contaminated with eggs. Antibodies were not produced in mice dosed with non-viable eggs. The results are consistent with the hypothesis that cestode parasites express phase- (or stage-) specific antigens.

Animals↗
PubMed1989

Granulocytopenia and thrombocytopenia associated with combination therapy of amphotericin B and low-dose flucytosine in a patient with cryptococcal meningitis.

A patient was admitted complaining of fever and headache. He was suspected of meningitis due to nuchal rigidity, and a lumbar puncture was performed. The patient was diagnosed as having cryptococcal meningitis, as Cryptococcus neoformans was found in an India ink preparation of the cerebrospinal fluid. Both amphotericin B and low-dose flucytosine (50 mg/kg/d) were concomitantly administered to the patient and his clinical symptoms improved. However, the combination therapy induced granulocytopenia and thrombocytopenia, which resolved after discontinuance of the drugs. Amphotericin B alone failed to cause granulocytopenia or thrombocytopenia. These results suggest that the mechanisms of granulocytopenia and thrombocytopenia may be toxic reactions to flucytosine in the azotemic state caused by amphotericin B. Our report emphasizes the need for clinicians to monitor for granulocytopenia and thrombocytopenia in patients receiving treatment with both amphotericin B and flucytosine, even when flucytosine is administered in a low dose.

Adult↗
PubMed1989

Localization of beta II subspecies of protein kinase C in beta-cells.

Protein kinase C (PKC) has been generally accepted to play a key role in stimulus-response coupling in various secretory cells, including pancreatic islets and pancreatic acini. The enzyme exists as a large family of multiple subspecies with highly related structures (alpha-, beta I-, beta II-, gamma-, delta-, epsilon-, and zeta-PKC). With an immunocytochemical procedure with subspecies-specific antibodies, beta II-PKC-like immunoreactivity was identified to localize in the beta-cells of the rat pancreatic islets. Neither beta I- nor gamma-PKC-like immunoreactivity was found in both islets and acini. Biochemical analysis confirmed that the rat whole pancreatic tissues contain a significant amount of alpha-PKC and a minute amount of beta II-PKC but neither beta I- nor gamma-PKC. On the other hand, beta II-PKC-like immunoreactivity was not detected in rat insulinoma cells, in which insulin secretion was induced in response to 12-O-tetradecanoylphorbol-13-acetate and carbachol but not in response to glucose. These findings suggest that beta II-PKC is the major, if not the sole, subspecies of PKC in beta-cells of rat pancreatic islets and a possible candidate for involvement in glucose-induced insulin secretion.

Animals↗
PubMed1989

Characterization of metalloproteinases in rat gastric tissues with acetic acid-induced ulcers.

To clarify the destruction of connective tissue in ulcerated regions, collagenase and gelatinolytic activities in homogenates of rat acetic acid-induced ulcers were examined. Gelatinolytic activity in the ulcerated regions was significantly higher than that in normal tissues. Collagenase, however, was not detectable. Gelatin-gel-electrophoresis showed that the gelatinolytic activity was due to several species, some of which crossreacted with a sheep anti-(rabbit prostromelysin) antibody. The H2-blocker, famotidine, significantly depressed the gelatinolytic activity in the ulcerated regions. Thus, both stromelysin and gelatinolytic enzymes may play important roles in the degradation of the basement membrane, especially type IV collagen.

Acetates↗
PubMed1989

[Dental anthropological study of the Central American Indians].

The purpose of this study was to evaluate the dento-craniofacial morphology and the occlusal characteristics in the Central American Indians from the dental-anthropological point of view. The sample consisted of cephalograms, pantomograms, dental casts, photos and records (anthropometric measurements and oral examinations) which were taken from 210 modern Central American Indians and 212 ancient Central American Indians. The results were summarized as follows: 1. Craniofacial morphology: The modern Central American Indians showed; (1) smaller facial height and shorter depth of the cranial base and jaws than those of the Caucasians. (2) posterior position of peri-orbital structures, and smaller values of anterior facial height in comparison with the Japanese, which were similar to the Peruvian Indians. (3) shorter depth of the jaws and prominence of the chin than the ancient Central American Indians. 2. Dental arch form and tooth size: The modern Central American Indians had; (1) wider dental arches than the Caucasians, while sharing similar values with the Peruvian Indians and the Japanese. (2) smaller incisors, larger premolars and molars in the mesio-distal crown diameter compared with the Caucasians. (3) smaller teeth in the mesio-distal crown diameter than the ancient Central American Indians. 3. Occlusal conditions: The modern Central American Indians showed a good mesio-distal relationship between the upper and lower first molars in 70 percent.

Adolescent↗
PubMed1989

Seborrheic keratosis with possible central regression.

We describe a case of suspected superficial-type basal cell epithelioma. However, it showed the histologic features of pigmented seborrheic keratosis and, on the basis of the clinical and histologic findings and the developmental course, was presumed to have undergone central regression. Mononuclear cell inflammation was considered to be involved in the regression.

Dermatitis, Seborrheic↗
PubMed1989

Induction of cataract in methylnitrosourea treated Fischer (F344) rats.

Cataracts were observed in female F344 rats who intravenously received methylnitrosourea (MNU), a potent carcinogen for multiple organs, in one dose of 50 mg/kg body weight. Induction of cataract 40 weeks after MNU treatment was 41% whereas no cataract was observed in control rats. The aggregation of beta H-crystallin fraction by MNU was studied in vitro. HPLC pattern of beta H-crystallin changed when lens protein was incubated for 24 hrs with MNU. HPLC patterns indicated that MNU induced high molecular weight aggregates of beta H-crystallin. This study conveys some indication about the direct interaction of MNU with lens protein in cataract formation.

Animals↗
PubMed1989

Hyaluronic acid metabolism in inflamed mesenterium of guinea pig.

Hyaluronic acid is known to play an important role in tissue remodeling and inflammatory process. To clarify the metabolism of hyaluronic acid in peritonitis, the biosynthesis of glycosaminoglycans in mesenterium was investigated in caseinate-induced peritonitis in guinea pig. Mesenterium showed acute inflammatory changes with polymorphonuclear leukocyte infiltration and produced much hyaluronic acid with a high molecular weight. Radioautography of inflamed tissue incubated with (3H)glucosamine demonstrated that radioactivity was incorporated predominantly by mesothelial cells and fibroblasts in the submesothelial cell layer. Intraperitoneal injection of human recombinant interleukin-1 alpha induced intraperitoneal accumulation of hyaluronic acid and its production by mesenterium. Heatlabile stimulating factor(s) for the biosynthesis of hyaluronic acid was present in the peritoneal fluid of inflamed guinea pigs. These results indicate that mesenterium is a hyaluronic acid-producing tissue and inflammatory changes of mesenterium are essential for the initiation and/or stimulation of hyaluronic acid production.

Animals↗
PubMed1989

Increase in glutathione disulfide level regulates the activity of microsomal glutathione S-transferase in rat liver.

Glutathione disulfide stimulates the activity of rat liver microsomal glutathione S-transferase 2-fold after incubation at 25 degrees C for 10 min. When the microsomes were incubated with the disulfide for over 20 min, the transferase activity increased to the same extent as in the case of N-ethylmaleimide (6-fold). Even in the presence of reduced glutathione, some enhancement of the transferase activity was observed. The data presented here are evidence that increase in glutathione disulfide level, e.g. by lipid peroxidation, on endoplasmic reticulum causes the upregulation of microsomal glutathione S-transferase activity.

Animals↗
PubMed1989

[Experimental studies on the sealing properties of various kinds of root canal sealers in vitro (Part 3)].

In previous studies (Shikwa Gakuho 80: 473-485, 1471-1486, 1980), the authors have reported on sealing properties in vitro. But the recent development of many new sealers makes necessary a detailed reexamination at this time. The experimental materials were as follows; Zinc oxide eugenol sealer......Canals Calcium hydroxide eugenol sealer......CRCS, Dentalis KEZ Calcium hydroxide guaiacol sealer......FR Hydroxyapatite sealer......Finapec APC, Apatite root sealer TYPE III The experimental procedure employing a glass tube and the dye-penetration method was similar to the one used in previous studies. Results of the investigation; 1. Degrees of dye penetration were classified into 3 types i) Immediate penetration through the zone between the material and the glass tube within 2 days.--Apatite root sealer TYPE III, Dentalis KEZ ii) Little penetration within 12 hours but gradual penetration to the deep zone thereafter.--CRCS, Canals iii) Slight penetration within 7 days and then gradual penetration 1/5 of the way through the zone between the material and the glass tube.--Finapec APC 2. Dye penetrated through the material in the case of apatite root sealer TYPE III and FR.

Dental Leakage↗
PubMed1989

Effects of Nd: YAG low power laser irradiation on the ulnar nerve.

In our previous study, we have shown that low power laser irradiation of the stellate ganglion produces a rise in temperature in the bilateral facial skin. To clarify the mechanism behind this phenomenon, irradiation was performed on the ulnar nerve at the elbow joint. The sensation felt during irradiation was reported by the subjects. Changes in temperature of the hand dorsum were thermographically recorded. The evoked peripheral autonomic surface potentials (PASP) were also recorded. 77.3% of the subjects reported sensation changes in the hand; the temperature rose in both hands in 3 out of 5 subjects. The PASPs did not show marked changes in latency or amplitude. It is suggested that the effects of the irradiation are brought about mainly through the stimulation of the central nervous system.

Action Potentials↗