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Y Shirasu

Publications and source records attributed to Y Shirasu.

At least 55 records · Page 3Linked to original sources
PubMed1988

Production and characterization of monoclonal antibodies to human pancreatic elastase 2.

Three murine monoclonal antibodies (MAbs) against human pancreatic elastase 2 (ELS-2) were produced by hybridomas obtained from the fusion of murine myeloma cells, P3X63-Ag8.-653, with the splenocytes of mice immunized with recombinant human proELS-2 (r-proELS-2) and purified natural ELS-2. These MAbs were found to recognize the different epitopes of ELS-2 based on a competitive binding assay. In addition, one of the MAbs, E19, reacted with the activation peptide of ELS-2. Western blot analysis performed under nonreducing conditions indicated that all MAbs bound only to ELS-2 in pancreatic juice in addition to natural ELS-2. Reduced ELS-2 on a Western blot could not be detected with E19, indicating that the activation peptide remained attached to active ELS-2 via a disulfide bond even after tryptic activation. Another MAb, B4, inhibited the enzymatic activity of ELS-2, indicating that B4 recognized the active site or its vicinity to ELS-2.

Animals↗
PubMed1988

Molecular cloning of complementary DNA encoding one of the human pancreatic protease E isozymes.

We have cloned a DNA from a human pancreatic cDNA library using a cloned rat pancreatic elastase 1 cDNA as a probe, and determined its nucleotide sequence. This cDNA contains a coding region of 810 nucleotides which encodes a 270-amino-acid protein. The deduced amino acid sequence shows less than 60% homologies with rat and porcine pancreatic elastase 1, although its substrate binding region is homologous with those of the above elastases 1. When this deduced amino acid sequence was compared with known amino acid sequences of pancreatic proteases other than elastases, it was found to contain an amino acid sequence which was highly homologous with the N-terminal amino acid sequence of porcine pancreatic protease E. We also purified human pancreatic protease E isozymes from human pancreatic juice, and determined their N-terminal amino acid sequences. One of the isozymes does not hydrolyze elastin but does hydrolyze a synthetic substrate. Endoglycosidase F digests glycoside bonds of the isozyme. These results suggest that the cDNA cloned by us corresponded to one of the human protease E isozymes.

Amino Acid Sequence↗
PubMed1988

Anti-rat myoglobin antisera in the immunocytochemical diagnosis of rhabdomyosarcomas of rats.

Anti-rat myoglobin (Mb) was prepared and used in the avidin-biotin-peroxidase complex (ABC) method on paraffin-embedded sections of nine soft tissue tumors (including two rhabdomyosarcomas) of rats. Distribution and nature of the reactive substance to Mb antiserum were compared to those of desmin antiserum. Rat Mb was isolated from the skeletal muscle; monospecificity of the rat antiserum was confirmed by the immunoblotting procedures. The Mb antiserum reacted specifically to normal and neoplastic striated muscle cells. Mb-staining reactions were present diffusely in the cytoplasm, while desmin-staining substances were localized at Z-bands or were diffuse in the cytoplasm as separated aggregates. Reaction to the Mb serum was also detected in cells of thick portions of Henle's loop and distal convoluted tubules.

Animals↗
PubMed1988

[Acute reversible cataract due to nitrocompounds in Japanese quail (Coturnix coturnix japonica)].

The present study was designed to examine the usefulness of the Japanese quail as an experimental model of cataractogenic activity. Chemicals, 2, 6-dibromo-4-nitro-phenol (2, 6-D), 2, 4-dinitroanisole (2, 4-DA), and 2, 4-dinitrophenol (2, 4-D; for the positive control), were administered singly through an oral route to 2-week old male Japanese quails to investigate the reversibility of cataracts. A single administration of 2, 4-D (36 and 43 mg/kg) produced reversible cataract in 14 of 16 animals (87.5%). This cataract was seen 1 or 2 hours after treatment and continued for 1 to 12 hours. Treatment with 2, 6-D (20 and 25 mg/kg) and 2, 4-DA (120 and 150 mg/kg) caused cataracts in 7 of 11 (63.6%) and 8 of 8 surviving animals (100%), respectively. Cataracts produced by 2, 6-D and 2, 4-DA, which were observed from 1 and 2 to 4 hours after the treatment, continued for 6 to 15 and 1 to 13 hours, respectively. Mortalities in the 25 mg/kg group of 2, 6-D, 120 mg/kg and 150 mg/kg group of 2, 4-DA were found in 2 of 5 animals, 1 of 5 animals and 5 of 9 animals, respectively. These results indicate that the Japanese quail is useful as an animal model to evaluate toxicity to the eye and cataractogenesis.

Acute Disease↗
PubMed1988

Morphological and genetic characteristics of the open-eyelid mutant spontaneously occurring in NC-strain mice.

A heritable open-eyelid mutant which arose spontaneously in the NC strain of mouse in 1982 has been maintained as the NC-eob line through brother-sister matings. When the line exceeded the 12th generation, its reproductive capabilities were initially compared with those of the NC strain. Then eye abnormalities were investigated morphologically and genetically. Although most of the reproductive parameters in the NC-eob line were comparable to those in the NC strain, a significant decrease was observed in the mean number of pups delivered, and the viability of pups at 7 days of age was reduced to 55%. The eyelids of pups were widely open at birth. The exposed cornea dried within a few hours and a bloody exudate appeared around the margin of the eyelids. At 1 day of age, the eye opening was smaller in size and covered with a scab. Histological examination demonstrated apparent inflammatory changes in the cornea and conjunctiva. At 21 days of age, the eyes revealed opacity, a rough surface, and microphthalmia. Histological findings in the cornea, such as keratosis and vascularization, coincided with the eye opacity. The weight and size of the eyeballs were almost the same as those in normal NC pups. However, a significant decrease in the length of the palpebral rima was evident and this was considered to be the cause of the microphthalmia. The results of genetic analysis indicated that these eye abnormalities were caused by an autosomal recessive gene, eob. These results suggested that the eob gene might be a new mutation manifesting semi-lethality as a pleiotropic effect.

Animals↗
PubMed1987

Effects of antimutagenic flavourings on SCEs induced by chemical mutagens in cultured Chinese hamster cells.

Effects of antimutagenic flavourings such as vanillin, ethylvanillin, anisaldehyde, cinnamaldehyde, coumarin and umbelliferone on the induction of SCEs by MMC were investigated in cultured Chinese hamster ovary cells. None of these 6 flavourings showed any SCE-inducing activity by themselves. However, an obvious increase in the frequencies of SCEs was observed when MMC-pretreated cells were cultured in the presence of each flavouring. All these compounds have either an alpha, beta-unsaturated carbonyl group or a carbonyl functionality neighbouring the phenyl group which may react with an enzyme SH-group and cause higher-order structure changes. SCE-enhancing effects of vanillin were further investigated on 6 other kinds of mutagens. Vanillin was also effective on SCEs induced by EMS, ENNG, ENU or MNU. On the other hand, MMS- or MNNG-induced SCEs were not influenced at all by vanillin. SCE-enhancing effects of vanillin seemed to be dependent on the quality of lesions in DNA.

Animals↗
PubMed1987

Contribution of monoaminergic nervous system in potentiation of 2-sec-butylphenyl N-methylcarbamate (BPMC) toxicity by malathion in male mice.

Malathion-induced marked potentiation of BPMC toxicity (about fivefold) was analyzed by measuring LD50 as an index of acute toxicity. The acute lethality of BPMC was decreased by muscarinic blockers (atropine, methylatropine, or trihexyphenidyl) or a monoamine oxidase inhibior (pargyline) and increased by a monoamine depleter (reserpine) or a dopaminergic blocker (haloperidol). The potentiation observed with BPMC and malathion was decreased by the muscarinic blockers, monoamine depleters (reserpine, alpha-methyl-p-tyrosine), an alpha-noradrenergic blocker (phentolamine), or haloperidol. The acute toxicities of other N-methylcarbamates MPMC (3,4-dimethylphenyl N-methylcarbamate), MTMC (3-methylphenyl N-methylcarbamate), NAC (1-naphthyl N-methylcarbamate), and XMC (3,5-dimethylphenyl N-methylcarbamate) were potentiated by malathion to a lesser degree than that of BPMC. Atropine protected against the lethalities of all N-methylcarbamates. Reserpine or haloperidol potentiated the lethalities of N-methylcarbamates with a similar tendency toward malathion. When the inhibitory effect of each N-methylcarbamate on brain acetylcholinesterase (AChE) was compared with its LD50, among five N-methylcarbamates BPMC had particularly strong anti-AChE activity. This characteristic of BPMC was not observed after the treatment with reserpine. These results suggest that BPMC may act not only on cholinergic nerves as an anti-AChE, but also on monoaminergic nerves which antagonize the lethal cholinergic effect. Malathion might inhibit the effect of BPMC on the monoaminergic nerves, thereby markedly potentiating the lethal effect of BPMC.

Acetylcholinesterase↗
PubMed1987

Potentiations of N-methylcarbamate toxicities by organophosphorus insecticides in male mice.

A N-methylcarbamate insecticide, 2-sec-butylphenyl N-methylcarbamate (BPMC), is markedly potentiated by low-dose treatments of P = S type organophosphorus insecticides. As a mechanism of this potentiation, the increase of plasma BPMC concentrations due to the inhibited metabolic degradation has been suggested. In this study, acute toxicities of five N-methylcarbamates structurally related to BPMC were studied after low-dose treatments of three P = S type organophosphorus insecticides (cyanophos, fenitrothion, and malathion) and one P = O type organophosphorus insecticide (dichlorvos), and the role of plasma concentrations of N-methylcarbamates in the potentiations was examined. Acute toxicities of five N-methylcarbamates were potentiated by the treatments of the P = S types, among which the potentiation of BPMC was strongest. BPMC toxicity was not potentiated by the treatment of the P = O type. Plasma concentrations of BPMC were increased by the treatments of the P = S types, but not by the treatment of the P = O type. The acute toxicity and plasma concentrations of BPMC were increased by SKF 525-A (an inhibitor of mixed-function oxidase). These results suggest that the increase of plasma BPMC concentrations may be related to the potentiation of BPMC toxicity. The treatment of fenitrothion increased plasma concentrations of other N-methylcarbamates more than those of BPMC, although the potentiation of BPMC toxicity was strongest. SKF 525-A and fenitrothion treatments increased plasma BPMC concentrations to a similar degree, but the potentiation of BPMC toxicity by SKF 525-A was significantly less than that by fenitrothion. Thus, some other mechanism(s) may be responsible for the potentiations of the N-methylcarbamate toxicities.

Animals↗
PubMed1987

Molecular cloning and expression in Escherichia coli of a cDNA encoding human pancreatic elastase 2.

We have cloned a DNA that is complementary to the messenger RNA that encodes human pancreatic elastase 2 from a human pancreatic cDNA library using a cloned cDNA for rat pancreatic elastase 2 messenger RNA. This complementary DNA contains the entire protein coding region of 807 nucleotides which encodes preproelastase of 269 amino acids, and 4 and 82 nucleotides of the 5'- and 3'-untranslated sequences, respectively. When this deduced amino acid sequence was compared with known amino acid sequences it showed 82% homology with rat pancreatic elastase 2. This deduced sequence also contains a 16-amino-acid peptide identical with the N-terminal sequence determined for native human pancreatic proelastase 2. Taking the above findings together, we conclude that the cloned cDNA encodes a mature enzyme of 241 amino acids including 16 and 12 amino acids for a signal peptide and an activation peptide, respectively. Moreover, the predicted key amino acid residues involved in determining the substrate specificity of mammalian pancreatic elastase 2 are retained in the human enzyme. Cloned human pancreatic elastase 2 cDNA was expressed in E. coli as a mature and pro-form protein. Both resulting proteins showed immunoreactivity toward anti-elastase serum and enzymatic activity. We have also cloned and sequenced a porcine pancreatic elastase 2 cDNA.

Amino Acid Sequence↗
PubMed1987

Oral leukoplakia and costochondral hyperplasia induced by diethylnitrosamine in hamsters exposed to cigarette smoke with or without dietary vitamin C.

Male Syrian golden hamsters receiving 12 weekly subcutaneous injections of diethylnitrosamine (DEN) were subjected to cigarette smoke-inhalation and fed a diet or without 1% vitamin C supplement for a period of 58 weeks. Another group was a sham-smoked control and was not fed vitamin C. Tissues of the oral cavity and costal cartilage were examined by light and/or scanning electron microscopy. Oral leukoplakia and costochondral hyperplasia occurred with high frequency in all groups treated with DEN. Leukoplakic lesions were found in the palate, tongue, and pharynx; the early change was focal erosion with mild epithelial hyperplasia and inflammatory cell infiltration. Advanced lesions had marked mucosal thickening due to acanthosis, parakeratosis, hyperkeratosis, and submucosal infiltration of lymphocytes and plasma cells. Precancerous lesions were noted in tongue and pharynx. Scanning electron microscopy of tongues revealed destruction of filiform papillae. The incidence of leukoplakic lesions were higher in smoke-exposed hamsters than in controls, but the incidence in vitamin C-supplemented hamsters was low when compared with the smoke-exposed hamsters without vitamin C. Costochondral hyperplasia was initiated by thickening of the perichondrium followed by proliferation of chondrocytes. Costochondral hyperplasia appeared earlier, and the incidence was higher in the vitamin C-supplemented hamsters. It could not be determined whether costochondral hyperplasia was the primary lesion induced by DEN or secondary change.

Animals↗
PubMed1986

Antimutagenic effects of 5-fluorouracil and 5-fluorodeoxyuridine on UV-induced mutagenesis in Escherichia coli.

Inhibitors of UV induction of the SOS function were screened. A log phase culture of E. coli PQ37 (sulA::lacZ, rfa, uvrA, Phoc) was irradiated with UV and then immediately subjected to culture for 2 h in a liquid LB medium containing each test compound. Expression of the SOS gene (sulA) was assayed by monitoring the levels of beta-galactosidase. In order to examine the inhibitory effects of test compounds on protein synthesis, the levels of the constitutive alkaline phosphatase were assayed in parallel. The total number of compounds tested was 233, including 44 food and feed additives, 23 naturally occurring compounds and derivatives, 21 antibiotics, 61 pesticides, 33 inorganics and 51 other chemicals. As a result, 5-fluorouracil and 5-fluorodeoxyuridine were found to inhibit considerably the UV induction of the SOS gene without any inhibition of protein synthesis. Mutagenesis induced by UV irradiation was depressed by the addition of either compound at non-toxic concentrations.

Alkaline Phosphatase↗
PubMed1986

Inhibitory effects of flavourings on mutagenesis induced by chemicals in bacteria.

The antimutagenic potential of twenty-five flavourings was tested against the activity of several kinds of chemical mutagens in Escherichia coli and Salmonella typhimurium. Anisaldehyde, ethylvanillin and vanillin showed marked antimutagenic effects on mutagenesis induced by 4-nitroquinoline 1-oxide, furylfuramide (AF-2), captan or methylglyoxal in E. coli WP2s. However, they were not effective against mutations provoked by 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) or 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in S. typhimurium TA98. Despite the decrease in the number of mutants, a remarkable increase was observed in the survival of mutagen-treated WP2s cells after exposure to these flavourings. We assume that these compounds may act as bio-antimutagens by enhancing an error-free recombinational repair system, because this reactivation of survival was strictly dependent on the recA gene function but not on the lexA and uvrA gene functions.

Benzaldehydes↗