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Biomedical subjects

S Miwa

Publications and source records attributed to S Miwa.

At least 163 records · Page 9Linked to original sources
PubMed1993

Phase II study of recombinant human granulocyte-macrophage colony-stimulating factor in myelodysplastic syndrome and aplastic anemia.

As phase II study, we treated 18 patients with myelodysplastic syndrome (MDS) and 37 patients with aplastic anemia (AA) with recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) for 14-28 days. Administration of rhGM-CSF resulted in a dose-dependent increase in circulating granulocyte counts, which was statistically significant in patients with AA. There were no consistent changes in monocyte and lymphocyte counts. Although no increase in both thrombocyte and erythrocyte counts was detected in the majority of the patients, a response of both lineages to rhGM-CSF, in addition to granulocyte lineage, was observed in 3 patients. Drug-associated adverse events developed in 28 patients (51%). The most frequent adverse event was fever. In general, the treatment with rhGM-CSF was well tolerated. The results suggest that rhGM-CSF is effective for patients with MDS and AA.

Adolescent↗
PubMed1993

Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) after chemotherapy in patients with non-Hodgkin's lymphoma; a placebo-controlled double blind phase III trial.

To assess the clinical and hematopoietic effects of rhGM-CSF, a placebo-controlled double blind multicenter phase III study was undertaken in patients with non-Hodgkin's lymphoma receiving cytotoxic chemotherapy. Sixty-two patients who had granulocytopenia (< 1 x 10(3)/microliters) after the first cycle of chemotherapy with cyclophosphamide, adriamycin, vincristine, and prednisolone were enrolled. After the second cycle of chemotherapy with the same regimen, patients randomly received either rhGM-CSF (125 micrograms/m2/day) or placebo for 14 days (rhGM-CSF; 31 patients and placebo; 31 patients). Administration of rhGM-CSF induced a significant increase in granulocytes mainly with neutrophils, eosinophils and monocytes, but elevation of lymphocytes, platelets, and reticulocytes was not induced. Median days of granulocytes less than 1 x 10(3)/microliters in patients receiving rhGM-CSF were significantly shorter than in patients receiving placebo (p = 0.001). Adverse reactions encountered with rhGM-CSF, and observed in 58% of the patients were never life-threatening and always rapidly reversible. They included fever, nausea and vomiting, diarrhea, skin eruption, and malaise. These results suggest that rhGM-CSF can be safely administered to prevent neutropenia after chemotherapy in patients with non-Hodgkin's lymphoma.

Adolescent↗
PubMed1993

Pharmacological properties of nicotinic acetylcholine receptors on adrenal chromaffin cells and their modification by hypoxic exposure.

To characterize the properties of nicotinic acetylcholine receptors (nAChRs) in autonomic ganglia, we examined specific L-[3H]nicotine binding to membrane fraction prepared from cultured bovine adrenal chromaffin cells, using a modified filtration method. Binding of L-[3H]nicotine to non-treated glass fiber filters interfered with detection of specific binding to the membrane fraction. Presoaking the glass fiber filters in 3% or greater concentrations of polyethyleneimine solution (sixty times higher than the reported concentration) for more than 5 h could reduce the binding of L-[3H]nicotine to the filters to background level. Furthermore, specific L-[3H]nicotine binding to the membrane fraction was detected only when the membrane fraction was prepared in buffer containing no divalent cations such as Ca2+ and Mg2+ (EDTA and EGTA were added) and protease inhibitors. Specific binding of L-[3H]nicotine was saturable and reversible. Scatchard analysis revealed a single class of high affinity binding sites with an average Kd of 8.7 nM and a Bmax of 43.2 fmol/mg protein. Specific binding was sensitive to cholinergic agonists (carbamylcholine and L-nicotine) and ganglionic stimulating agents (lobeline and DMPP), but was resistant to neuromuscular blocking agents (alpha-bungarotoxin, d-tubocurarine) and hexamethonium. These results suggest that high-affinity nicotine binding sites on adrenal chromaffin cells are nAChRs of ganglion-type, which have properties different from nAChRs on the neuromuscular junction but similar to nAChRs in the brain.

Animals↗
PubMed1993

Human glucose-6-phosphate dehydrogenase: structure and function of normal and variant enzymes.

Glucose-6-phosphate dehydrogenase (G6PD) is a unique enzyme with many genetic variants. Recent progress in molecular biological techniques have provided several important findings about the structure-function relationship of human G6PD. A putative substrate glucose-6-phosphate binding (around Lys 205) and a putative 'structural' NADP binding site (around Lys 386) have been identified. A conservative segment (amino acid 38-44) near the N-terminus was proposed to be the possible second NADP binding region (amino acid 38-44). Analysis of amino acid substitutions of variants revealed that there might be some relationship between the position of substitution and the properties of variants.

Amino Acid Sequence↗
PubMed1993

[The amnioinfusion therapy of saline solution for premature rupture of the membranes before 27 weeks' gestational age].

Saline solution amnioinfusion was performed for 12 cases of preterm PROM before 27 weeks gestational age complicated by oligohydramnios in order to suppress chorioamnionitis, prevent fetal pulmonary hypoplasia and delay delivery. The results were as follows. 1. The mean gestational ages at diagnosis of premature rupture of membranes and initiating saline solution amnioinfusion were 23.6 +/- 2.9 weeks and 24.9 +/- 1.5 weeks, respectively. The mean duration of saline solution amnioinfusion was 14.7 +/- 11.9 days. The mean gestational age at delivery was 27.2 +/- 1.7 weeks. The mean birth weight was 1,056 +/- 220g. 2. Saline solution amnioinfusion was effective in relieving oligohydramnios in all cases. No pulmonary hypoplasia was observed in the infants. 3. Clinically saline solution amnioinfusion was effective in suppressing chorioamnionitis in 9 cases out of 12. Histologically the picture of chorioamnionitis was revealed in 10 cases out of 12. no serious infection was observed in the infants. 4. Nine infants out of 12 survived. There were 2 IUFD and one neonatal death. The perinatal survival rate was 75%. 5. It is concluded from the above results that saline solution amnioinfusion is an effective treatment for preterm PROM before 27 weeks' gestational age.

Amnion↗
PubMed1992

Structural analysis of human pyruvate kinase L-gene and identification of the promoter activity in erythroid cells.

The human pyruvate kinase (PK) L-gene is organized in 12 exons over 9.5 kilobases, and the first and second exons are specifically transcribed to the R- and L-type PK mRNA. The 5'-flanking region upstream the first exon has two CAC boxes and four GATA motifs within 250 bp from the translational initiation codon. Comparison with the rat L-gene revealed four well-conserved elements in the region. The transient transfection demonstrated that the 270-bp upstream region was a powerful promoter in K562 cells, whereas deletion of the distal 150-bp sequences, which included three GATA motifs, resulted in drastic reduction of the activity. When the hypersensitive site 2 of the human beta-globin gene locus was joined to the promoter, the activity of the proximal 120-bp region was enhanced. We concluded that the proximal 120-bp region had a basal promoter activity and that the distal 150-bp region acted as an enhancer in erythroid cells.

Animals↗
PubMed1992

Assessment of dopamine and its metabolites in the intracellular and extracellular compartments of the rat striatum after peripheral administration of L-[11C]dopa.

Success in the synthesis of L-3,4-[beta-11C]dihydroxyphenylalanine (L-[11C]DOPA) and its application to positron emission tomography encouraged us to perform radioactive metabolite analyses in rats in an early phase after peripheral injection of L-[11C]DOPA. Following intravenous injection of [11C]DOPA, the radioactivity associated with DOPA and its metabolites was determined in the striatum after decapitation and in striatal extracellular fluid using in vivo brain microdialysis. Without pretreatment, 70-80% of 11C-radioactivity taken up into the striatum was associated with acidic metabolites of dopamine (DA) from 2 to 30 min after administration of L-[11C]DOPA with or without 300 micrograms/kg of unlabelled L-DOPA. In contrast, 80-90% of 11C-radioactivity in the striatum was associated with DOPA and DA after pretreatment with benserazide (25 mg/kg, i.p.) followed by administration of L-[11C]DOPA with or without unlabelled L-DOPA. The radioactivity in the DOPA fraction decreased with time (from 35% of 11C-radioactivity in the striatum at 5 min to 10% at 30 min), but that in the DA fraction increased (from 57% to 68%). The 11C-radioactivity in the extracellular fluid determined by brain microdialysis was less than 0.4% of that in the whole striatum and no radioactivity was present in the DA fraction. These results suggest that, in an early phase after administration of L-[11C]DOPA, [11C]DA is the main metabolite and is localized exclusively in the intracellular compartment within this time frame.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

A single amino acid substitution (157 Gly----Val) in a phosphoglycerate kinase variant (PGK Shizuoka) associated with chronic hemolysis and myoglobinuria.

We have determined a single amino acid substitution in a new phosphoglycerate kinase (PGK) variant, PGK Shizuoka, associated with chronic hemolysis and myoglobinuria. PGK Shizuoka had an extremely low enzyme activity with normal kinetic properties and normal electrophoretic mobility. Total blood cell RNA of the patient was reverse-transcribed and amplified by the polymerase chain reaction. A single nucleotide substitution from guanine to thymine at position 473 of PGK messenger RNA was found. This nucleotide change causes a single amino acid substitution from Gly to Val at the 157th position, which is located in the NH2-terminal domain of the enzyme. This mutation creates a new Bst XI cleavage site in exon 5, and we thus confirmed the mutation in the variant gene. The replacement of Gly by Val is considered to affect enzyme catalysis.

Adult↗
PubMed1992

Identical point mutations of the R-type pyruvate kinase (PK) cDNA found in unrelated PK variants associated with hereditary hemolytic anemia.

We cloned and sequenced the cDNAs for R-type pyruvate kinase (R-PK) from three homozygous PK patients. A point mutation (1151ACG to ATG) identified in the R-PK cDNA of PK Nagasaki was identical with that previously identified in an unrelated family, PK Tokyo. The mutation has also been identified in the PK L gene of a Lebanese family, PK Beirut, by Neubauer et al (Blood 77:1871, 1991). These results suggest either that the point mutation is very old or that the same mutation occurs sporadically in the same hot spot in unrelated families. A point mutation, 1261CAG to AAG, was detected in both PK Fukushima and PK Maebashi; this mutation causes a single amino acid substitution, from Gln421 to Lys, in R-PK. Consequently, the hydrophobicity properties near the mutated site are drastically changed. A silent mutation (1705AGG to CGG) was also identified in those variants. The screening of these three point mutations showed only the silent mutation in a normal individual as well as in individuals with PK variants. These results indicate that the multiplicity of the mutant PK allele is smaller than expected, and that the silent mutation is a polymorphic change commonly distributed in the Japanese population.

Anemia, Hemolytic, Congenital↗
PubMed1992

Regulation of acetylcholine release in vivo from rat hippocampus by monoamines as revealed by novel column-switching HPLC with electrochemical detection.

To clarify monoaminergic regulation of acetylcholine (ACh) release in the rat hippocampus, the effects of administration of monoamines through a dialysis probe on extracellular ACh levels were examined using in vivo brain microdialysis combined with a novel column-switching HPLC system. Infusion of dopamine or 5-hydroxytryptamine, but not noradrenaline, increased ACh levels. The ACh levels also increased following infusion of apomorphine and 5-methoxy-N,N-dimethyltryptamine. These results demonstrate that hippocampal ACh release is regulated by dopamine and 5-hydroxytryptamine.

Acetylcholine↗
PubMed1992

Monoamine-mediated enhancement of acetylcholine release in rat hippocampus by 6R-L-erythro-5,6,7,8-tetrahydrobiopterin.

Recently, we reported that intracerebroventricular administration of 6R-L-erythro-tetrahydrobiopterin (6R-BH4), a common natural cofactor for phenylalanine, tyrosine and tryptophan hydroxylases, enhances in vivo exocytotic release of acetylcholine (ACh) from the rat hippocampus, as monitored by brain microdialysis. In the present study, we developed a method for separation of ACh from 6R-BH4 on small columns of Sephadex G-10, which allowed us to determine by high pressure liquid chromatography (HPLC) the changes of ACh levels recovered in dialysates following addition of 6R-BH4 to the dialyzing fluid. Infusions of 6R-BH4 (final concentration, 0.25, 0.5 and 1 mM in the perfusing fluid) produced concentration-dependent increases in ACh levels in dialysates (1.5-, 3- and 8-fold of the basal levels, respectively), but was without effect on choline levels in dialysates. Infusion of 6S-L-erythro-5,6,7,8-tetrahydrobiopterin (6S-BH4), an unnatural diastereoisomer of 6R-BH4, or L-erythro-biopterin (biopterin), an oxidized form of 6R-BH4, did not affect the ACh levels in dialysates. The 6R-BH4-induced increase in ACh levels persisted after pretreatment with atropine, a muscarinic antagonist, but did not occur in rats pretreated with reserpine to deplete monoamines. These results show that 6R-BH4 stimulates exocytotic ACh release in the hippocampus through action on a local monoaminergic system in the hippocampus.

Acetylcholine↗
PubMed1992

Characterization of nicotinic acetylcholine receptors on cultured bovine adrenal chromaffin cells using modified L-[3H]nicotine binding assay.

To characterize the properties of nicotinic acetylcholine receptors (nAChRs) in autonomic ganglia, we examined L-[3H]nicotine binding to membrane fraction prepared from cultured bovine adrenal chromaffin cells, using a modified filtration method. Binding of L-[3H]nicotine to non-treated glass fiber filters interfered with the detection of specific binding to the membrane fraction. Presoaking glass fiber filters in 3% or higher concentrations of polyethyleneimine (PEI) solution (sixty times higher than earlier used concentration) for at least 5 h could reduce the binding of L-[3H]nicotine to the filters to the background level. Specific L-[3H]nicotine binding to the membrane fraction was detected only when the membrane fraction was prepared in Ca(2+)-and Mg2+ (EDTA, EGTA and protease inhibitors were added) -free buffer. Specific binding of L-[3H]nicotine was saturable and reversible. Both computer program and Scatchard analysis revealed a single class of high affinity binding sites with an average Kd of 8.9 nM and a Bmax of 42.5 fmol/mg protein. The Hill coefficient was 0.98. In inhibition studies, both cholinergic agonists (carbachol and L-nicotine) and ganglionic agonists (lobeline and 1,1-dimethyl-4-phenylpiperazinium iodide) were much effective in inhibiting L-[3H]nicotine binding, whereas both neuromuscular blocking (alpha-bungarotoxin and d-tubocurarine) and ganglionic blocking agents were less effective. These results suggest that high affinity nicotinic binding sites on adrenal chromaffin cells are nAChRs of the ganglion-type, which have properties different from nAChRs on the neuromuscular junction but similar to nAChRs in the brain.

Animals↗
PubMed1992

Molecular abnormality of a Japanese glucose-6-phosphate dehydrogenase variant (G6PD Tokyo) associated with hereditary non-spherocytic hemolytic anemia.

The entire coding sequence of a Japanese class 1 variant (G6PD Tokyo) was amplified by the polymerase chain reaction from genomic DNA. Nucleotide analysis by a direct sequencing technique revealed a unique nucleotide substitution (1246 G to A) in exon 10, which predicts a Glu to Lys substitution at the 416th amino acid. This is another member of a conspicuous mutation cluster surrounding the putative NADP-binding domain.

Anemia, Hemolytic↗
PubMed1992

A single nucleotide substitution in the phosphoglycerate kinase (PGK)-1 gene occurred after the separation of PGK-1 and PGK-2.

The mammalian genome contains two functional loci for the production of phosphoglycerate kinase, PGK-1, an X-linked gene expressed in all somatic cells, and PGK-2, an autosomal intron-less gene expressed exclusively in late spermatogenesis. A nucleotide substitution from guanine to thymine was recently found at position 473 of PGK-1 mRNA in PGK Shizuoka. The mutation was not found in the PGK-2 gene and might have occurred after separation of PGK-1 and PGK-2.

Animals↗
PubMed1992

L-dopa administration enhances exocytotic dopamine release in vivo in the rat striatum.

Peripheral administration of L-3,4-dihydroxyphenylalanine (L-DOPA) methylester increased extracellular levels of DOPA and dopamine (DA) in the rat striatum monitored by in vivo brain microdialysis. The increase in DA levels persisted after inhibition of DA reuptake by nomifensine. Administration of blockers of voltage-dependent Na+ (tetrodotoxin) or Ca2+ (NKY-722) channels through the dialysis membrane completely eliminated the increase in DA levels. These results demonstrate that the L-DOPA-induced DA release is exocytotic in nature and hence, derived from neurons in the striatum.

Animals↗
PubMed1992

Phase I/II study of recombinant human granulocyte-macrophage colony-stimulating factor in patients with advanced malignancy. The Multicenter Study Group.

The toxicity and hematologic effects of Escherichia coli-derived recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) were studied in 58 treatment cycles in Japanese patients with advanced malignancy as a phase I/II clinical trial. rhGM-CSF in doses from 30 to 250 micrograms/m2/day was administered by 24-hour continuous intravenous infusion, 8-hour intravenous, or a daily subcutaneous injection for 14 days. The most common adverse drug events (ADE) were fever, nausea/vomiting, diarrhea, skin eruption, and phlebitis. The frequency of moderate and severe ADE was 2.9, 14.7, 35.3 and 47.1% at 30, 60, 125, 250 micrograms/m2/day, respectively. In terms of administration routes, the frequency of ADE was 69% with 24-hour continuous intravenous infusion, 39.1% with 8-hour intravenous infusion and 16.7% with subcutaneous injection. Regarding the hematologic effects of rhGM-CSF, leukopenia improved in a dose-dependent manner. The appropriate dose level to be used in the phase II study was estimated to be in the range between 60 and 250 micrograms/m2/day.

Adult↗
PubMed1992

[A novel function of tetrahydrobiopterin].

6R-L-erythro-5, 6, 7, 8-Tetrahydrobiopterin (6R-BH4) is known as a cofactor for the hydroxylases of phenylalanine, tyrosine and tryptophan and also as a cofactor for nitric oxide synthase. Recently, a novel function of 6R-BH4 has been found: that is, 6R-BH4 acts on specific membrane receptors to directly stimulate the release of monamine neurotransmitters such as dopamine and serotonin, independently of its cofactor activity. In addition, it indirectly stimulates the release of non-monoamine neurotransmitters such as acetylcholine and glutamate, through activation of monoaminergic systems. In this paper, we briefly review recent experimental data, which provide new insights into the role of 6R-BH4 as a regulator of neuronal function. We also discuss the possibility of treatment by 6R-BH4 of neuropsychiatric diseases such as Parkinson's disease, Alzheimer's disease, depression and infantile autism.

Alzheimer Disease↗