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Biomedical subjects

H Inoue

Publications and source records attributed to H Inoue.

At least 1,531 records · Page 85Linked to original sources
PubMed1989

Effects of heat shock on the induction of mutations by chemical mutagens in Neurospora crassa.

Preheating of Neurospora conidia increased their susceptibility to mutation induction by chemical mutagens. Optimal conditions of heat shock for enhanced mutagenesis were determined in 2.5 X 10(7) conidia/ml 0.067 M KH2PO4-Na2HPO4 (pH 7.0) buffer to be treatment at 43 degrees C for 60 min. When protein synthesis during heat stock was eliminated by cycloheximide or by use of the temperature-sensitive mutation psi-1, induction of thermotolerance was inhibited while induction of the enhanced state of mutability was not. Therefore, inducible protein synthesis is not involved in this process. To discover whether DNA-repair systems are altered by heat shock and, as a result, whether reversion frequencies increase, DNA-repair mutants (upr-1, uvs-2, uvs-3, uvs-6, mus-7, mus-16) were heated and their reversion frequencies at the ad-8 locus were measured. All the DNA-repair mutants showed higher reversion frequencies with MNNG treatment after heat shock than in non-heated control. It therefore seems that DNA repair is not involved in the enhancement of chemical mutagenesis by heat shock. Heat shock does not increase frequencies of reversion induced by ultraviolet light, and heat shock after treatment with chemical mutagens does not affect reversion frequencies. These results suggest that heat shock may change the structure and function of cellular membranes and thereby increase the influx of mutagens into cells.

DNA Repair↗
PubMed1989

Epistasis, photoreactivation and mutagen sensitivity of DNA repair mutants upr-1 and mus-26 in Neurospora crassa.

Double mutants were constructed combining mus-26, formerly designated uvs-(SA3B), with other UV-sensitive mutants. Tests of sensitivity of these double mutants to UV and to chemical mutagens revealed that mus-26 and upr-1 belong to the same epistatic group. The UV dose-response curve of mus-26 showed a characteristic plateau in the range of 100-200 J/m2. The same characteristic was also shown in the dose-response curves of upr-1 and the double mutant, upr-1 mus-26. Photoreactivation of UV damage in mus-26, upr-1 and upr-1 mus-26 was defective but not null. Assays were made of the reversion rate of ad-8 in strains that also carried UV-sensitive mutations. The reversion frequencies of the strains with upr-1 and upr-1 mus-26 were very low for the UV dose range below 300 J/m2, similarly to mus-26. Previously reported homozygous sterility of mus-26 was not caused by the mus-26 locus itself, and fertile strains were obtained among progeny. The results of this study suggest that mus-26 and upr-1 have similar properties in DNA repair.

4-Nitroquinoline-1-oxide↗
PubMed1989

Identification and structure of the rat true tissue kallikrein gene expressed in the kidney.

Genomic clones carrying the entire rat true tissue kallikrein gene have been isolated and characterized. Southern blot analysis revealed the presence of a unique gene for true tissue kallikrein in the rat haploid genome. The true tissue kallikrein gene was composed of 5 exons and 4 introns, its length being about 4.5 kilobase pairs. We also isolated the rat renal kallikrein cDNA which was expressed in the kidney. The exon sequences of the gene were identical with the corresponding sequences of the kallikrein cDNA. The rat true tissue kallikrein gene was distinct from two rat kallikrein-related genes expressed in the kidney (Chen, Y. et al. (1988) Biochemistry 27, 7189-7196). Primer extension analysis indicated that two identical transcription-initiation sites were used in both the kidney and submandibular gland, although expression of the true tissue kallikrein in the submandibular gland was much higher than that in the kidney. The 3'-noncoding region of this gene contained the polyadenylation signal, AATAAA, observed in the rat renal kallikrein cDNA. The 5'-flanking region was sequenced up to about 800 base pairs, upstream of the cap sites. CATCT, GGGCGG, and TTTAAA boxes were found as common signals required for eukaryote gene expression within about 100 base pairs-upstream of the cap sites.

Animals↗
PubMed1989

Isolation and characterization of temperature-sensitive mutants of Abelson murine leukaemia virus that exhibit dissociation among morphological transformation, soft agar colony-forming ability and tyrosine kinase activity.

Seven temperature-sensitive (ts) mutants of Abelson murine leukaemia virus (A-MuLV) were isolated on the basis of the temperature dependence of their soft agar colony-forming ability. These seven ts mutants exhibited similar characteristics and were not ts for morphological transformation and autophosphorylation of P120gag-abl protein. The dissociation of the properties of morphology, soft agar colony formation and tyrosine kinase activity might suggest that the v-abl product has more than one primary intracellular target.

Abelson murine leukemia virus↗
PubMed1989

Suppressive effect of interferon-beta-activated natural killer cells on lipopolysaccharide-induced B cell differentiation of MRL/Mp-lpr/lpr mice.

The suppressive effects of mouse recombinant interferon-beta (IFN-beta) on B cell differentiation of MRL/Mp-lpr/lpr (MRL/1) mouse, a model of autoimmune diseases, and C3H/H2 mice, a normal situation, were investigated. Spleen mononuclear cells were cultured in the presence of lipopolysaccharide (LPS), and the suppressive effect of IFN-beta was examined on differentiation of B cells to plaque-forming cells (PFCs) by highly sensitive reversed hemolytic plaque assay. IFN-beta (5,000-10,000 units/ml) suppressed more than 50% of PFCs of both MRL/1 and C3H/H2 mice. This suppressive activity as well as the cytotoxicity of natural killer (NK) cells enhanced by IFN-beta was abrogated by treatment of the spleen cells with anti-asialo GM1 antibody in the presence of complement. This suppressive activity was also abrogated by intravenous administration of 20 microliter/mouse of anti-asialo GM1 12 hr before cultivation of spleen cells. These results suggest that NK cells activated by IFN might be responsible for the immunoregulation in autoimmune diseases.

Animals↗
PubMed1989

Inhibition of in vitro tumor cell invasion by transmethylation inhibitors.

Three inhibitors of S-adenosylmethionine-mediated transmethylation, 5'-methylthioadenosine (MTA), 2'-deoxyadenosine and sinefungin, inhibited in vitro invasion by a highly invasive clone (Cl-30) of rat ascites hepatoma cells, AH 130 (AH cells). Difluoromethylthioadenosine (DFMTA), a non-metabolizable derivative of MTA, also caused strong inhibition of invasion at concentrations that did not suppress the growth of the tumor cells. Cl-30 cells precultured in methionine-depleted medium showed decreased invasiveness. DFMTA was also effective on the invasion by fibrosarcoma, B16 melanoma and human lung carcinoma cell lines.

Adenosine↗
PubMed1989

Amplification of both c-myc and c-raf-1 oncogenes in a human osteosarcoma.

Fourteen human bone and soft part tumor tissues were screened by Southern blot hybridization using five oncogene probes (c-myc, c-K-ras, c-fos, c-raf-1, and N-myc). Amplification of c-myc was found in two osteosarcomas and one malignant fibrous histiocytoma. One of these osteosarcomas had amplified c-raf-1 gene. Rearrangement of the amplified gene was not observed. This is the first report of c-raf-1 amplification in human cancer tissues.

Adolescent↗
PubMed1989

Endotracheal neurilemoma with a lymphoid cuff. An ultrastructural and immunohistochemical study.

A neurilemoma occurred in the trachea of a 63-year-old woman complaining of dyspnea. Microscopically, the excised tumor was composed predominantly of cellular areas of Antoni type A tissue and had a peripheral lymphoid cuff. The schwannian origin was confirmed both immunohistochemically and ultrastructurally. This tumor without nuclear palisading and Verocay bodies differed somewhat from a conventional soft tissue neurilemoma and closely resembled a particular form of neurilemoma of the stomach, previously reported as a unique entity. Thus, this type of neurilemoma does occur in sites other than the gastrointestinal tract.

Female↗
PubMed1989

A simplified Master's two-step test for preschool children.

To investigate the usefulness of a simplified Master's two step test (s-MTT) for preschool children aged 4-6, s-MTT was carried out in our pediatric cardiology clinic using a new stair and connector for joining the leads from each child to the ECG machine. The subjects were 21 children with Kawasaki disease without coronary involvement and four children with arrhythmias. The treadmill exercise test (TET) was done on the same day to compare the exercise load of s-MTT with that of TET. Oxygen uptake during s-MTT was also examined using another group consisting of eight outpatients. There were no differences in indices such as peak heart rate (HR), HR immediately after exercise, and performance ratio between the outpatients in this study and kindergarteners in the preliminary report. The proportions of peak HR and HR immediately after exercise in s-MTT to those in TET were 91.1 +/- 7.9 (mean +/- SD)% and 91.1 +/- 8.6%, respectively. The average oxygen uptake of the eight outpatients in s-MTT was 23.2 +/- 4.1 ml/min/kg. These studies suggest that the simplified MTT is useful as a screening test, because it can be done for all children aged 4-6 in any laboratory.

Cardiovascular Diseases↗
PubMed1989

Modulation by glycyrrhetinic acid derivatives of TPA-induced mouse ear oedema.

1. The anti-inflammatory effects of glycyrrhetinic acid and its derivatives on TPA (12-O-tetradecanoylphorbol-13-acetate)-induced mouse ear oedema were studied. The mechanisms of TPA-induced ear oedema were first investigated with respect to the chemical mediators. 2. The formation of ear oedema reached a maximum 5 h after TPA application (2 micrograms per ear) and the prostaglandin E2 (PGE2) production of mouse ear increased with the oedema formation. 3. TPA-induced ear oedema was prevented by actinomycin D and cycloheximide (0.1 mg per ear, respectively) when applied during 60 min after TPA treatment. 4. Of glycyrrhetinic acid derivatives examined, dihemiphthalate derivatives (IIe, IIe', IIIa, IIIa', IVa, IVa') most strongly inhibited ear oedema on both topical (ID50, 1.6 mg per ear for IIe, 2.0 mg per ear for IIIa and 1.6 mg per ear for IVa) and oral (ID50, 88 mg kg-1 for IIe', 130 mg kg-1 for IIIa' and 92 mg kg-1 for IVa') administration. 5. Glycyrrhetinic acid (Ia) and its derivatives applied 30 min before TPA treatment were much more effective in inhibiting oedema than when applied 30 min after TPA. A dihemiphthalate of triterpenoid compound IVa completely inhibited oedema, even when applied 3 h before TPA treatment. 6. Glycyrrhetinic acid (Ia) and deoxoglycyrrhetol (IIa), the parent compounds, produced little inhibition by oral administration at less than 200 mg kg-1. 7. These results suggest that the dihemiphthalate derivatives of triterpenes derived from glycyrrhetinic acid by chemical modification are useful for the treatment of skin inflammation by both topical and oral application.

Animals↗
PubMed1989

Summation and inhibition by ultrarapid train pulses in dogs: effects of frequency and duration of trains, lidocaine, and beta blockade.

To test whether summation and inhibition of excitation by ultrarapid train pulses were modified by frequency and duration of trains, using lidocaine and beta blockade, the strength-interval relationship was determined with a single extrastimulus and train pulses (100 and 200 Hz) in 28 anesthetized, open-chest dogs. The effective refractory period (ERP) determined at greater than or equal to 5 mA was shorter for trains than for single stimulus (summation). Summation determined at 15 mA increased progressively as the duration of trains was increased to 50 msec after which it reached a plateau. ERP determined at less than or equal to 2 mA was longer with train pulses than with single stimulus (inhibition). Inhibition for 200 Hz trains increased linearly with train duration up to 200 msec, while for 100 Hz trains it became constant when the duration was greater than or equal to 80 msec. Lidocaine (plasma concentration: 2.6 +/- 1.0 micrograms/mL) did not affect inhibition and summation in 11 dogs. Propranolol (1 mg/kg, iv) increased summation at 15 mA (n = 7, 30 +/- 10 vs 46 +/- 11 msec with 100 Hz trains, P less than 0.01), but did not affect inhibition (37 +/- 26 vs 29 +/- 17 msec, NS). In conclusion, (1) effect of frequency of train pulses was more on inhibition than on summation; (2) lidocaine did not affect inhibition and summation; and (3) propranolol increased summation but not inhibition.

Adrenergic beta-Antagonists↗
PubMed1989

[Bacteriological investigation on an outbreak of acute enteritis associated with verotoxin-producing Escherichia coli O111:H-].

An outbreak of acute enteritis in children aged one to thirty-three months occurred from June 10th to 23rd, 1986, at a private orphanage in Matsuyama City. Twenty-two out of 23 children suffered from diarrhea. Nine of the 22 children excreted bloody stool. Fever and vomiting were observed with a few patients. One of them, a 33-month-old girl, developed hemolytic uremic syndrome, and died twelve days after the admission. Escherichia coli O111:H- was isolated from fecal specimens of 7 out of 15 patients. The culture filtrate of the isolate caused fluid accumulation in ligated ileal loops in a rabbit, and was lethal to mice. It was found that all isolates produced two kinds of Vero toxins (VT1 and VT2, or shiga-like toxin I and II). The amount of VT2 produced in vitro was about 10 times more than that of VT1.

Acute Disease↗
PubMed1989

[Infant botulism was confirmed in Ehime Prefecture].

The third case of infant botulism in Japan is reported. A four-month-old baby boy suddenly had weakness of suckling force, constipation and generalized hypotonicity. He was the product of normal gestation, labor and delivery. Growth and development were normal until he was nineteen weeks old. He received fruit-juice and honey daily. By bacteriological examination, Clostridium botulism type A was isolated from his feces and the honey which he had received. Type A toxin was detected from his feces but not from his serum.

Botulism↗
PubMed1989

Isolation and characterization of a laccase-derepressed mutant of Neurospora crassa.

Laccase from the ascomycete Neurospora crassa is an inducible secretory enzyme. Production of this enzyme is repressed in vegetative cultures but can be induced by treatment with low concentrations of cycloheximide. Isolation and characterization of a derepressed mutant, the lah-1 mutant, that is capable of producing laccase in vegetative cultures without induction by cycloheximide are described. The lah-1 mutation is mapped between nit-2 and leu-3 on linkage group I, and it behaved as a recessive mutation in a forced heterokaryon. No differences were detected biochemically or immunologically between the laccase protein produced by the lah-1 mutant in the absence of cycloheximide and that induced with cycloheximide in the wild-type strain. This suggests that both laccases (66 kilodaltons) are products of the same structural gene. Relative amounts of laccase in the culture filtrate of the lah-1 mutant were much higher than those induced with cycloheximide in the wild-type strain, demonstrating high efficiency of the lah-1 mutant in production and secretion of laccase. The time course of laccase production by the lah-1 mutant revealed that expression of 66-kilodalton laccase was repressed in conidia and derepressed during vegetative mycelial growth. This suggests that a multiple regulatory mechanism is involved in the production and/or maturation of Neurospora laccase. The lah-1 mutant may be useful for identifying genes that regulate expression of the laccase gene in N. crassa.

Chromatography↗
PubMed1989

Electrophysiological study of young patients with exercise related paroxysms of palpitation: role of atropine and isoprenaline for initiation of supraventricular tachycardia.

Electrophysiological studies were performed in eight patients (four men and four women, mean (SD) age 24 (5) years with paroxysmal attacks of palpitation during or immediately after exercise. Five patients were competitive athletes at college. In two patients spontaneous supraventricular tachycardia during exercise was recorded by ambulatory electrocardiographic monitoring and in another it was induced by treadmill exercise testing. Two had dual atrioventricular nodal pathways, three had manifest atrioventricular accessory pathways, and three had concealed atrioventricular pathways. Programmed stimulation induced sustained supraventricular tachycardia in six patients--in two after intravenous injection of atropine sulphate (1 mg) and in four during infusion of isoprenaline (0.01 microgram/kg/min). In one patient, non-sustained atrioventricular nodal reentrant tachycardia was induced during isoprenaline infusion. In the remaining patient, who had dual atrioventricular nodal pathways, tachycardia was not inducible. AH block prevented maintenance of reentry in five patients. In five patients shortening of the effective refractory period of the atrioventricular node with atropine (one patient) and isoprenaline (four patients) caused sustained supraventricular tachycardia. The present study indicates that treatment with atropine and isoprenaline may be an important factor in the initiation of supraventricular tachycardia in patients with exercise related paroxysms of palpitation.

Adult↗
PubMed1989

Sensory receptors and reflex pathways of nonadrenergic inhibitory nervous system in feline airways.

The sensory receptors and reflex pathways of the nonadrenergic inhibitory nervous system (NAINS) were examined, using separately ventilated left and right lungs in cats. During bronchoconstriction induced by 5-hydroxytryptamine (5-HT) (50 to 250 micrograms/kg/min, i.v.) infusion after atropine (3 mg/kg, i.v.) and propranolol (2 mg/kg, i.v.), one lung was challenged with (1) citric acid aerosol or (2) capsaicin aerosol or (3) lung volume change (lung inflation). Citric acid or capsaicin inhalation to one lung produced significant bronchodilatation in not only the stimulated lung (SL) but also in the opposite lung (OL). The 5-HT-induced change in pulmonary resistance (RL) was reduced 66.5 +/- 3.3% (mean +/- 1 SE) (SL) and 53.0 +/- 8.1% (OL) by citric acid (20%) and 40.5 +/- 8.9% (SL) and 44.0 +/- 9.9% (OL) by capsaicin (0.1%) inhalation, respectively. These bronchodilatations were abolished by bilateral vagotomy. Inflation of one side of the lung did not reduce the 5-HT-induced change in RL in the OL. These findings indicate that (1) C-fiber and irritant receptors are the possible sensory receptors of the NAINS reflex pathway, and (2) afferent nerve stimulation of NAINS in one lung can produce reflex bronchodilatation in both lungs.

Animals↗