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Y Minatogawa

Publications and source records attributed to Y Minatogawa.

At least 37 records · Page 2Linked to original sources
PubMed1995

Spin-labelling study of biomembranes in spontaneously hypertensive rats: calcium- and calmodulin-dependent regulation.

1. The present study was performed to investigate alterations in membrane characteristics of spontaneously hypertensive rats (SHR) by using an electron paramagnetic resonance (EPR) and spin-labelling methods. 2. Washed erythrocytes from SHR were examined and compared with erythrocytes from age-matched normotensive Wistar-Kyoto (WKY) rats. 3. The values of outer hyperfine splitting (2T' 11) and that of the order parameter (S) obtained from EPR spectra for a spin label agent (5-nitroxide stearate) were significantly higher in the erythrocytes of SHR than in those of WKY rats. 4. When calcium (Ca2+) was loaded to erythrocytes with a Ca2+ ionophore (A 23187), the order parameter (S) of the EPR spectra showed a greater increase in SHR than in WKY rats. Furthermore, the Ca2+ -induced change in the order parameter (S) of SHR was significantly antagonized by pretreatment of the Ca2+ antagonists (verapamil, diltiazem) and a calmodulin antagonist (W-7). 5. The results show that the erythrocyte membranes of SHR tolerated different spin motions from those of normotensive WKY rats in the EPR study, which might be associated with the idea that the membrane fluidity might be lower in SHR. Furthermore, the data suggest that Ca2+ -calmodulin antagonists may ameliorate the Ca2+ -induced changes in membrane functions in hypertension.

Animals↗
PubMed1994

DNA fragmentation during the programmed cell death in the chick limb buds.

Programmed cell death plays a crucial role in limb morphogenesis of amniote. So far, there has been no biochemical evidence found to support the fact that embryonic cell death is apoptosis. In this report, we show the oligo-nucleosomal ladder pattern of DNA obtained from interdigital tissues of chick leg buds, indicating that programmed cell death has some features that are common to those involved in apoptosis. Furthermore, cells exhibiting DNA fragmentation were detected by using a method of in situ end labeling of DNA breaks. The distribution pattern of those cells corresponded well to those of programmed-dead cells situated within the interdigital mesenchyme of the leg bud.

Animals↗
PubMed1994

Changes of some serum parameters and amino acids content in rats after chronic sublethal doses of dimethoate.

An intraperitoneal repeated dose of dimethoate (O,O-dimethyl S-[N-methylcarbamoyl methyl] phosphorodithioate) was injected to male Wistar rats for 8 successive days. Body weight and liver weight decreased significantly while liver/body weight ratio and mg protein/g liver remained unchanged. Twenty serum amino acids were assayed in blood samples collected from hepatic vein, portal vein, and aorta. Most of the measured amino acids showed a tendency of decrease compared to control. The decrease was significant only for taurine, serine, threonine, methionine, tyrosine, histidine, and arginine but not for the rest of the amino acids measured. Glucose, 3-hydroxybutyrate, urea, ammonia, and lactate were measured in the same serum samples. These serum parameters showed a tendency of decrease (except urea) of them from control but the decrease was not significant.

3-Hydroxybutyric Acid↗
PubMed1993

Autosomal codominant inheritance and Japanese incidence of deficiency of OKT4 epitope with lack of reactivity resulting from conformational change.

A large Japanese family in which some members were homozygous or heterozygous for OKT4 epitope deficiency was studied. Homozygotes, heterozygotes, and normal individuals were identified by differences in the number of OKT4 epitopes on the surfaces of lymphocytes. This deficiency was transmitted as an autosomal codominant trait. The internalization of CD4 molecules and the production of IL-2 by lymphocytes of these subjects were examined. The OKT4 epitope was not needed for internalization of CD4 molecules, and IL-2 was produced in the same amounts by these different kinds of subjects. DNA from four clones lacking OKT4 established from four individuals of this family was sequenced. As reported elsewhere for different subjects, a single nucleotide substitution (CGG-->TGG) was found in all four cell lines. The mutation results in arginine being replaced by tryptophan. Analysis showed different hydrophobicity at positions 239 and 240 from the control, probably giving rise to a conformational change in CD4 accounting for lack of reactivity with the OKT4 monoclonal antibody. The incidence of homozygotes in the Japanese population was found to be 0.47% by examination of 1478 random samples, and on the basis of this value, the incidence of heterozygotes was estimated to be 12.8%.

Amino Acid Sequence↗
PubMed1993

Urinary neopterin as a predictive marker of coronary artery abnormalities in Kawasaki syndrome.

We investigated whether urinary neopterin concentrations respond to the pathological conditions (especially coronary artery dilatation) of Kawasaki syndrome. All of 29 children with Kawasaki syndrome had very high urinary neopterin concentrations. Increased urinary neopterin concentrations coincided with fever and with monocytosis in peripheral blood. The urinary neopterin excretion peaking within the first 8 days after onset correlated with the development of coronary artery dilatation. Increased urinary neopterin concentrations indicate that cell-mediated immunity is activated in patients with Kawasaki syndrome. Endogenous interferon-gamma and activation of monocytes/macrophages may play a role in the pathogenesis of Kawasaki syndrome. Not only do neopterin concentrations correlate with symptoms in the acute phase of Kawasaki syndrome, they also act as a predictive marker of coronary artery abnormalities in affected patients.

Biomarkers↗
PubMed1992

Gene structure of human indoleamine 2,3-dioxygenase.

Two genomic DNA clones that encode human indoleamine 2,3-dioxygenase (IDO) were isolated from the human genomic DNA library using the IDO cDNA as a probe, and their restriction maps and partial nucleotide sequences were determined. The human IDO gene spanned 15 kilobase pairs with ten exons. The 5' terminus of the IDO mRNA was 33 nucleotides upstream of the translation initiation codon ATG. The 5' flanking region contained ISRE, X-box, and Y-box like sequences. Southern blot analysis of the human genomic DNA indicated that the human IDO gene was present in a single copy in the genome.

Alternative Splicing↗
PubMed1992

A glycine-to-glutamate substitution abolishes alanine:glyoxylate aminotransferase catalytic activity in a subset of patients with primary hyperoxaluria type 1.

We have synthesized and sequenced alanine:glyoxylate aminotransferase (AGT; HGMW-approved symbol for the gene--AGXT) cDNA from the liver of a primary hyperoxaluria type 1 (PH1) patient who had normal levels of hepatic peroxisomal immunoreactive AGT protein, but no AGT catalytic activity. This revealed the presence of a single point mutation (G----A at cDNA nucleotide 367), which is predicted to cause a glycine-to-glutamate substitution at residue 82 of the AGT protein. This mutation is located in exon 2 of the AGT gene and leads to the loss of an AvaI restriction site. Exon 2-specific PCR followed by AvaI digestion showed that this patient was homozygous for this mutation. In addition, three other PH1 patients, one related to and two unrelated to, but with enzymological phenotype similar to that of the first patient, were also shown to be homozygous for the mutation. However, one other phenotypically similar PH1 patient was shown to lack this mutation. The mechanism by which the glycine-to-glutamate substitution at residue 82 causes loss of catalytic activity remains to be resolved. However, the protein sequence in this region is highly conserved between different mammals, and the substitution at residue 82 is predicted to cause significant local structural alterations.

Alanine↗
PubMed1991

Kinetic properties of human liver tryptophan pyrrolase.

Human liver tryptophan pyrrolase (TPO) activity exhibited substrate level regulation. TPO showed biphasic activity to tryptophan when low ascorbate was used as an activator. The high affinity form (Km for tryptophan: 0.05 mM) was promoted by low ascorbate and low tryptophan. The low affinity form (Km for tryptophan: 0.4 mM) was induced by high concentrations of tryptophan or ascorbate. Both high and low affinity forms showed the same affinity to oxygen. The high affinity form was also induced by pyrroloquinoline quinone, but this effect was decreased by catalase, suggesting the participation of H2O2.

Ascorbic Acid↗
PubMed1991

In vitro effect of dimethoate on the activity of tryptophan pyrrolase in rat liver.

Total and holo-enzyme activities of tryptophan 2,3-dioxygenase were measured in vitro in the presence and absence of the organophosphorous insecticide, dimethoate. Addition of dimethoate to the reaction mixture decreased the activities of both total and holo-forms. Total and holo-enzyme activities were decreased by 34% and 26%, respectively, by 1 mM dimethoate. On the other hand, 5 mM dimethoate resulted in 56% and 34% inhibition to total and holo-enzyme activities, respectively. Lineweaver-Burk plot of the total-enzyme activity at different tryptophan concentration in the presence of 2 mM dimethoate gave uncompetitive type of inhibition.

Animals↗
PubMed1990

Effects of anticonvulsants and gamma-aminobutyric acid (GABA)-mimetic drugs on immunoreactive somatostatin and GABA contents in the rat brain.

Immunoreactive somatostatin (IR-SRIF) and gamma-aminobutyric acid (GABA) contents in the rat brain were investigated to study chronic effects of the treatment with anticonvulsants, carbamazepine (CBZ), valproic acid (VPA) and phenytoin (PHT). Decreased IR-SRIF levels were found in several brain regions after chronic treatment with VPA and CBZ. GABA concentrations were found to be increased significantly in chronic CBZ and VPA treatment in the rat brain, especially in limbic structures. PHT had no effect on both IR-SRIF and GABA contents in the rat brain. Effects of several GABA-mimetic drugs also were studied on IR-SRIF contents in the rat brain. Aminooxyacetic acid an inhibitor of GABA transaminase, induced a decrease in IR-SRIF concentration in the pyriform and entorhinal cortex, whereas ethanolamine-o-sulfate, another GABA-transaminase inhibitor and muscimol, a GABA receptor agonist had no effect on brain IR-SRIF after acute administration. The present results suggest that endogenous somatostatin has an important role for anticonvulsant properties of CBZ and VPA, but not of PHT. The relationship between the changes in IR-SRIF and the GABA transmitter system in the anticonvulsant action of CBZ and VPA remains to be clarified.

Aminooxyacetic Acid↗
PubMed1990

Effects of some insecticides on several enzymes of tryptophan metabolism in rats.

The activities of tryptophan 2,3-dioxygenase (EC 1.13.11.11), indoleamine 2,3-dioxygenase (EC 1.13.11.17), kynurenine 3-hydroxylase (EC 1.14.13.9), kynureninase (EC 3.7.1.3), kynurenine transaminases, and pyridoxal phosphokinase (EC 2.7.1.35) in the liver, kidney and lung rats were measured after administration of a single dose and repeated doses of dimethoate, carbaryl and fenvalerate, respectively. Ten percent LD50 of each insecticide was orally administered to a rat for a single dose, while 5% LD50 was orally given for five consecutive days as repeated doses. The control animals received the same volume of vehicle (polyethylene glycol 300). Body weight and organs weight losses were recognized only after repeated doses of dimethoate, while protein content remained constant compared to control animals. Repeated administration of dimethoate caused significant decrease in the activity of kynurenine 3-hydroxylase (28.3% decrease in liver, and 32.5% in kidney), kynurenine-pyruvate transaminase (EC 2.6.1.7) (40% in liver, and 24.2% in kidney), kynurenine- pyruvate transaminase (EC 2.6.1-) (24.5% in kidney) and pyridoxal phosphokinase (36.1% in liver). Repeated doses of carbaryl resulted in a significant decrease in the activity of apo-tryptophan 2,3-dioxygenase (42.8%), kynurenine-2-oxoglutarate transaminase (40% in liver), kynurenine-pyruvate transaminase (30.6% in liver), and serine-glyoxylate transaminase (EC 2.6.1.51) (47.9% in liver). Externally added insecticides at different concentrations to the incubation mixture resulted in an inhibition to tryptophan 2,3-dioxygenase, while the other enzymes examined showed no change in their activities.

Animals↗
PubMed1988

Decreased membrane fluidity of erythrocytes and cultured vascular smooth muscle cells in spontaneously hypertensive rats: an electron spin resonance study.

1. Membrane fluidity of erythrocytes and cultured vascular smooth muscle cells was studied in spontaneously hypertensive rats (SHR; Okamoto and Aoki strains) by means of an electron spin resonance (e.s.r.) and a spin-label technique. 2. The values of outer hyperfine splitting (2T') and of the order parameter (S) determined from e.s.r. spectra for a fatty acid spin-label agent (5-nitroxy stearate) were significantly higher in erythrocytes of SHR (4 and 10-13 weeks of age) than in those of age-matched Wistar-Kyoto rats (WKY). This finding suggests that the membrane fluidity of erythrocytes might be decreased in SHR. 3. The fluidity of cultured vascular smooth muscle cells obtained from 10-13-week-old SHR was also reduced compared with that from WKY. 4. These results suggest that the decreased membrane fluidity might be a genetically determined abnormality of the cell membranes in SHR.

Animals↗
PubMed1988

Effects of calcium antagonists on membrane fluidity in hypertension--an electron spin resonance study.

We examined alterations in membrane fluidity of hypertension and the effects of calcium antagonists on these changes by means of an electron spin resonance (ESR) and spin-label technique. Washed erythrocytes from spontaneously hypertensive rats (SHRs; aged 4 and 10-13 weeks) and from patients with essential hypertension, or cultured vascular smooth muscle cells from SHRs were examined and compared with those from normotensive controls. Electron spin resonance spectra for a fatty acid spin label-agent (5-nitroxy stearate) in the membranes were obtained. The values of hyperfine splitting and other parameters of the spectra were significantly higher in erythrocytes from hypertensive rats than in normotensive controls. Similar results were obtained in cultured vascular smooth muscles. These findings indicate that the membrane fluidity might be decreased in hypertension. When calcium was loaded to erythrocytes with Ca-ionophore A23187, the fluidity was decreased. The alternative degrees were greater in hypertensive rats than in controls, and these hypertensive changes were antagonized by diltiazem or verapamil. The results revealed that abnormalities of membrane fluidity in hypertension might be more prominent in the presence of calcium. Further, it is suggested that calcium antagonists could correct these membrane abnormalities in hypertension.

Adult↗