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Biomedical subjects

Y Kurosawa

Publications and source records attributed to Y Kurosawa.

At least 37 records · Page 2Linked to original sources
PubMed1999

High IL-18 (interferon-gamma inducing factor) concentration in a purine nucleoside phosphorylase deficient patient.

The plasma concentration of IL-18 (interferon-gamma inducing factor) was severely increased in a 3 year old boy with purine nucleoside phosphorylase (PNP) deficiency. The presence and activity of IL-18 were confirmed by immunoblotting and bioassay, respectively. These results suggest that IL-18 may be abundantly produced and secreted into plasma by PNP deficient macrophages in PNP deficiency.

Biomarkers↗
PubMed1999

Protective action of angiotensin converting enzyme inhibitors on cardiac hypertrophy in the aortic-banded rat.

Imidapril, enalapril and quinapril were subcutaneously administered to aortic-banded rats by osmotic minipumps to compare the suppressive actions of these angiotensin converting enzyme (ACE) inhibitors on pressure-induced cardiac hypertrophy. Among the three drugs tested, imidapril was most potent for the prevention of cardiac hypertrophy, although equipotent hypotensive doses were used. Imidapril reduced both serum and cardiac ACE activities, while enalapril reduced only the former. Quinapril also reduced both, however, it was less potent at reducing the former compared to imidapril. Moreover, only imidapril significantly decreased left ventricular end diastolic pressure, which tended to be increased by aortic-banding. The lipophilicity of ACE inhibitors could not explain the more potent suppressive action of imidapril on cardiac hypertrophy because the lipophilicity of imidaprilat, an active metabolite of imidapril, was as low as an active metabolite of enalapril; i.e., much lower than an active metabolite of quinapril. The efficacy of ACE inhibitors on pressure-induced cardiac hypertrophy depends not only on an inhibitory effect on cardiac ACE activity, but also on other actions such as their effect on left ventricular end diastolic pressure.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

Expanded genomic organization of conserved mammalian MHC class I-related genes, human MR1 and its murine ortholog.

MR1 is a major histocompatibility complex (MHC) class I-related gene located outside the human MHC. Among several divergent class I molecules, the predicted MR1 molecule is closest, in the alpha1 and alpha2 domains, to the class I group to which the vertebrate classical class I molecules belong. We report here the genomic organizations of the human MR1 and mouse Mr1 genes. Both genes exhibit genomic structures largely similar to those of the MHC class I genes. However, they are highly expanded in their scale in contrast to the classical MHC class I genes. Inclusion of transposable elements into introns seems to partly contribute to these genomic structures. Several other MHC class I-related genes also show relatively large genomic structures. The present study extended heterogeneity in the genomic organization among the class I gene family by revealing a highly expanded structure of the human MR1 gene and its murine ortholog.

Amino Acid Sequence↗
PubMed1998

Direct evidence of autosomal recessive inheritance of Arg24 to termination codon in purine nucleoside phosphorylase gene in a family with a severe combined immunodeficiency patient.

Purine nucleoside phosphorylase (PNP) deficiency is a rare immunodeficiency disease involving a T-lymphocyte-dysfunction that is fatal unless bone marrow transplantation is successful. In this study we undertook genetic analysis of a patient with PNP deficiency. Sequencing of the PNP gene, which is located on chromosome 14ql3, of the patient led to the identification of three point mutations in exon 2 at amino acid positions 20 (His, silent mutation), 24 (Arg-->termination codon) and 51 (Ser-->Gly). Intrafamilial sequence analysis of exon 2 revealed that both parents were heterozygous for the Arg24 and termination codon 24 alleles. Two of their three children had inherited different homozygous alleles, termination codon 24 for the patient, and Arg24 for his healthy sibling. Transcriptional termination was suggested as the mechanism giving rise to the disorder in this case. A lack of PNP protein was also confirmed by immunoblot analysis of the patient's hemolysate. This could be the first report providing evidence of autosomal recessive inheritance in PNP deficiency by sequence-based analysis.

Amino Acid Sequence↗
PubMed1998

Temperature dependency of thermodynamic parameters in interactions between hen egg-white lysozyme (HEL) and anti-HEL antibodies.

We examined temperature dependency of thermodynamic parameters in the interactions between hen egg-white lysozyme (HEL) and anti-HEL antibody, D1.3, and two mutant antibodies. The DeltaH degrees values appeared to decrease biphasically in the temperature range from 10 to 45 degrees C with the apparent inflection point around 30 degrees C. The DeltaG degrees calculated from the KA values showed only small differences because of entropy and enthalpy compensation. It has been argued that large negative values of heat capacity change (DeltaCp degrees), if observed, are mainly derived from hydrophobic interactions. However, the observed DeltaCp degrees values were too high to be ascribed only to hydrophobic interactions. Moreover, addition of methanol did not cause a decrease in the absolute value of DeltaCp degrees.

Amino Acid Substitution↗
PubMed1998

Characterization of Fv fragments expressed on phage surface.

We characterized a phage antibody in which an Fv fragment, namely, a free VH fragment noncovalently associated with a VL fragment that is fused with a truncated cpIII molecule (VL-DeltacpIII), is expressed on the phage surface. D1.3 antibody specific for hen egg-white lysozyme was used as a model system. Both VH and VL-DeltacpIII fragments were stably expressed and associated with each other to form a faithful antigen-binding site. The results of Western blotting indicated that more than 5% of phages expressed the Fv fragment on their surface. Analysis of the kinetics of binding of the phage antibody to the antigen suggested the possibility of presence of phages having multiple-binding sites on a single phage particle.

Animals↗
PubMed1998

Changes in the specificity of antibodies against steroid antigens by introduction of mutations into complementarity-determining regions of the V(H) domain.

An attempt was made to change the specificity of antibodies (Abs) by introduction of mutations. A monoclonal Ab specific for 17alpha-hydroxyprogesterone (17-OHP) was used as the starting Ab. On the basis of a model that was generated by a computer-driven model-building system, we constructed a phage-display library of Abs in which 16 residues were mutated in three complementarity-determining regions of the heavy chain that appeared to form the steroid-binding pocket. We screened the library with 17-OHP and cortisol that had been conjugated with bovine serum albumin, and we isolated many clones that had retained 17-OHP-binding ability as well as clones with the newly developed ability to bind cortisol in addition to 17-OHP. We compared the amino acid sequences between 17-OHP-specific and cortisol-binding Abs, and then constructed several additional Abs. Our results indicated that a change in specificity could be achieved by changing only a single, critical amino acid residue. Models of the 17-OHP-and cortisol-binding pockets formed by the mutated Abs could explain these observations.

17-alpha-Hydroxyprogesterone↗
PubMed1998

Pharmacologic profile of TA-606, a novel angiotensin II-receptor antagonist in the rat.

This study was carried out to characterize a novel angiotensin II-receptor antagonist, TA-606, (3-pentyloxy) carbonyloxymethyl-5-acetyl-2-n-propyl-3-[2'(1H-tetrazole-5-yl) biphenyl-4-yl]methyl-4,5,6,7-tetrahydro imidazo [4,5-c] pyridine-4-carboxylate hydrochloride, which is a newly synthesized prodrug of 606A. In anesthetized rats, 606A inhibited angiotensin II-induced pressor response with a median inhibitory concentration (IC50) of 6 microg/kg, i.v., and was 8 times more potent than EXP3174, an active metabolite of losartan. Bioavailability of TA-606 was 11 times higher than that of 606A in Sprague-Dawley rats, with consistent hypotensive potencies in spontaneously hypertensive rats (SHRs). In conscious renal hypertensive rats (RHRs) and conscious SHRs, TA-606 lowered the blood pressure without any effects on the heart rate, and its effective dose for 30 mm Hg (ED30) values were 0.14 and 0.21 mg/kg, p.o., respectively. The effect of TA-606 lasted > 10 h in both models. Moreover, the effect of TA-606 was approximately 30 and 10 times more potent than those of losartan in RHRs and SHRs, respectively. TA-606 did not affect the blood pressure in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. TA-606 given for 12 weeks attenuated the development of hypertension in stroke-prone SHRs. These results indicate that TA-606 is a potent angiotensin II-receptor antagonist with antihypertensive efficacy. Thus TA-606 is suggested to be a possible useful agent in the treatment of hypertension.

Angiotensin Receptor Antagonists↗
PubMed1998

Upregulation of nucleobindin expression in human-activated lymphocytes and non-Hodgkin's lymphoma.

Nucleobindin (Nuc) was originally found to be an enhancement factor of anti-DNA antibody production secreted by a lymphoid cell line derived from a lymphoproliferative MRL/lpr mouse. It has been shown that Nuc has a unique structure containing a DNA- and two calcium-binding domains, and a leucine zipper motif, but its biological roles have not yet been fully elucidated. Expression of Nuc was first studied in human lymphocytes. Expression of Nuc mRNA in normal peripheral blood mononuclear cells was significantly increased upon mitogen stimulation. Anti-human Nuc monoclonal antibody H-1D8 immunoprecipitated Nuc protein in the nuclear extract of Molt-4 cells. Furthermore, in the immunohistochemical staining of tumor specimens from 108 patients with non-Hodgkin's lymphoma (NHL) with H-1D8, H-1D8-positive cells were observed in nearly all cases in varying frequency. According to the Working Formulation, the percentage of cases in which more than 90% of the tumor cells were stained with H-1D8 was 65% in the high grade of the histological malignancy, 54% in the intermediate grade, and 22% in the low grade; however, normal cells surrounding the tumor cells were virtually negative for H-1D8. These results showed that the level of Nuc expression in human lymphocytes reflects the status of activation or proliferation of the cells, thus providing a clue for the further investigation into biological roles of Nuc. In addition, it might be applicable to the clinicopathological estimation of NHL as a novel indicator.

Adolescent↗
PubMed1998

Do intronic mutations affecting splicing of WT1 exon 9 cause Frasier syndrome?

The WT1 gene, one of the genes responsible for Wilms tumour, is thought to play a crucial role in the development of the kidneys and gonads. This gene encodes four protein isoforms resulting from two alternative splicing sites, one of which involves inclusion or exclusion of lysine, threonine, and serine (KTS) between the third and fourth zinc finger domains. WT1 is virtually always mutationally inactivated in patients with Denys-Drash syndrome. We analysed WT1 in eight patients who had been diagnosed as having this syndrome, and identified five previously unknown mutations affecting splicing donor sites of intron 9. These mutations affect alternative splicing. The isoforms retaining KTS are not produced. The clinical features of the patients with these intronic mutations were consistent with those of Frasier syndrome, characterised by a more slowly progressive nephropathy than Denys-Drash syndrome, associated streak gonads, and no Wilms tumour development. Our results indicate that WT1 isoforms, including/excluding KTS, have different functions in tumorigenesis and organogenesis of the kidneys and gonads.

Adolescent↗
PubMed1998

A novel angiotensin II-receptor antagonist, 606A, induces regression of cardiac hypertrophy, augments endothelium-dependent relaxation and improves renal function in stroke-prone spontaneously hypertensive rats.

It is well-known that cardiac hypertrophy and arterial and renal dysfunction are serious complications of hypertension. Therefore, we investigated the chronic effects of 606A (2-propyl-3-[2'(1H-tetrazole-5-yl)biphenyl-4-yl]methyl-5-acetyl-4,5,6,7- tetrahydro imidazo [4,5-c]pyridine-4-carboxylic acid disodium salt), a novel AT1-receptor antagonist, on these complications of hypertension in stroke-prone spontaneously hypertensive rats (SHRSP) using Wistar Kyoto rats (WKY) as the control. After 8 weeks treatment from 16 weeks of age with 606A by a subcutaneously implanted osmotic pump, cardiac function, cardiac weight, acetylcholine-induced endothelium-dependent relaxation in the isolated aorta and renal function were estimated. Furthermore, wall thickness of the left ventricle was studied morphologically. We found that 606A (0.3 mg, 1 mg and 3 mg/head/day) dose-dependently lowered blood pressure without any effects on heart rate in SHRSP. Long-term treatments with 606A significantly reduced cardiac weight, left ventricular wall thickness and left ventricular end diastolic pressure, whereas it did not affect cardiac contractility. Endothelium-dependent relaxation of the aorta was recovered, and total protein excretion as well as total protein excretion/creatinine excretion ratio was reduced to the level of WKY by the treatment. These results suggest that 606A not only has a hypotensive effect but also protects cardiac, renal and vascular tissues from complications of hypertension. Thus, 606A could be an useful drug for treatment of hypertension.

Acetylcholine↗
PubMed1998

Geographical variation of mandible size and shape in the Ryukyu wild pig (Sus scrofa riukiuanus).

We measured adult mandibles of Ryukyu wild pigs from Amami-Oshima, Kakeroma, Okinawa, Ishigaki and Iriomote Islands. The size cline was not statistically recognized among the populations of Nansei Islands. The Ishigaki population was significantly larger than Iriomote one in mandible length. Some measurement ratios indicated that the ramus is enlarged laterally and that the body of mandible is dorso-ventrally developed in Ishigaki and Iriomote populations. The Amami-Oshima mandibles were relatively smaller than those of Okinawa and Iriomote populations in length item of body of mandible. These results will contribute to the zoo-archaeology on the historical change of size and shape in the island populations, and to the evolutionary biology on the morphological adaptation of this animal.

Animals↗
PubMed1998

Multivariate analysis of mandible in the Ryukyu wild pig (Sus scrofa riukiuanus).

We measured adult mandibles of Ryukyu wild pig (Sus scrofa riukiuanus) from Tokunoshima Island and compared the osteometrical data with those from six Nansei Islands. The mandibles in Tokunoshima Island were larger than those from Amami-Oshima and Okinawa Islands in some measurements. We concluded that the size cline was not statistically recognized among populations. In the principal component analysis, the size cline was also denied, and the separation could be made among island populations in female. It is suggested that the populations in Tokunoshima and Okinawa Islands may be different from those in Amami-Oshima, Kakeroma, Ishigaki and Iriomote Islands in skull proportion.

Aging↗
PubMed1997

Instability of regions containing expanded CAG repeats during replication in Escherichia coli probed by labeled oligonucleotides.

The instability of plasmid DNAs that contained various numbers of repeated CAG units in Escherichia coli was examined. Synthetic [5'-32P](CAG)15 and [5'-32P]-(CTG)15 oligonucleotides were incubated with plasmid DNA. A minor fraction of the plasmid DNA formed a stable complex with either the repeated CAG or the repeated CTG oligonucleotide when the number of CAG repeats in the plasmid DNA was more than 30, regardless of the polarity of replication. The formation of the complexes appeared to occur by the normal hybridization process. The DNA that formed stable complexes could be purified with a biotinylated fragments of CAG repeats and avidin-coated beads. In addition, in the case of the DNA containing CAG repeats derived from the IT15 gene of a patient with Huntington's disease, there seemed to be an unusual product that contained a partially replicated product that extended only from the origin of replication to the CAG-repeated region. The formation of this product was observed when replication started downstream of IT15 gene.

Base Sequence↗
PubMed1997

A highly conserved major histocompatibility complex class I-related gene in mammals.

We report here a cDNA sequence of a murine homolog of the human major histocompatibility complex (MHC) class I-related gene, MR1. The analyses revealed unprecedentedly high conservation of MR1 in the alpha1 and alpha2 domains (corresponding to the peptide-binding domains in the classical MHC class I molecules) between human and mouse (predicted amino acid identity: 90 and 89% for the alpha1 and alpha2 domain, respectively), compared to MHC class I and other class I molecules. On the other hand, conservation in the alpha3 domain (73%) is comparable to those of others, suggesting domain-specific conservation of MR1. The localization of the mouse MR1 gene was determined to be chromosome 1H1, which corresponds to the human chromosomal region where the human MR1 gene is located (chromosome 1q25). High conservation of MR1 among mammals suggests that MR1 may be involved in critical conserved biological function(s).

Amino Acid Sequence↗
PubMed1997

Expression vectors for the introduction of highly diverged sequences into the six complementarity-determining regions of an antibody.

We prepared three kinds of phagemid vector that permit the simultaneous introduction of highly diverged sequences into six complementarity-determining regions (CDRs) of an antibody (Ab) by the polymerase chain reaction (PCR) with degenerate oligodeoxynucleotide (oligo) primers. The phages expressed either the Fv, single-chain Fv (sc Fv) or Fab form of an Ab fused with a half-molecule of cpIII on the surface of M13 phage. A phage-display library, composed of 2 x 10(8) independent clones, was constructed; the phages that were specific for hen egg-white lysozyme (HEL) were selected by three rounds of panning; and 20 clones were isolated. The isolated clones consisted of 17 different clones. Among them, 16 clones expressed proteins that were able to bind to HEL. The association constants for binding of the encoded proteins to HEL ranged from 1.48 x 10(6) to 7.71 x 10(6)/M. These vectors allowed us to prepare many libraries of artificial Ab in which the sequences of six CDRs were very different and reflected the artificial sequences that had been designed for the degenerate oligo that we used as primers for PCR. The libraries should be also useful for the analysis of relationships between the sequences of the CDRs and antigen (Ag) specificity.

Amino Acid Sequence↗
PubMed1997

Recombinant human TSH receptor expressed in E. coli.

We expressed the extracellular domain (20-408 aa, (T) of human TSH receptor (TSHR) in E. coli to detect TSHR autoantibodies (TRAb) and, moreover, we expressed the two portions (20-218 aa (5') and 217-408 aa (3')) of the extracellular domain thought to distinguish thyroid stimulating antibodies (TSAb) from blocking antibodies (TSBAb), using pGEX.3X as the expression vector. Using Western blotting analysis of the sera from patients with autoimmune thyroid disease, sera from Graves' patients and patients with idiopathic myxedema who had TSBAb reacted with the fusion protein (T), but none of the control sera reacted with it. We further evaluated whether or not the positive sear for T recognized fusion proteins (5') or (3'). The sera from Graves' patients reacted with both fusion proteins (5') and (3'). The sera from patients with idiopathic myxedema did not react with either of fusion proteins (5') or (3'). These findings suggest that these recombinant TSHR proteins could be used as antigens to detect TRAb, and differentiate TSABb from patients with idiopathic myxedema.

Antibodies, Blocking↗