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Biomedical subjects

K Hosoda

Publications and source records attributed to K Hosoda.

At least 19 recordsLinked to original sources
PubMed1992

Organization, structure, chromosomal assignment, and expression of the gene encoding the human endothelin-A receptor.

We have isolated and characterized the gene for the human endothelin-A receptor. Southern blot analyses demonstrated a single copy gene for the receptor. The gene spans more than 40 kilobases and contains eight exons and seven introns. Intron 1 exists in the 5'-noncoding region, and introns 2-7 occur in the coding region. The locations of introns 2-7 exist before or after the regions encoding the membrane-spanning domains. The transcription start site, determined by primer extension experiments, is 502 base pairs upstream of the methionine initiation codon. The 5'-flanking region lacks a typical TATA box but contains a potential SP-1-binding site 27 base pairs upstream of the transcription start site. Using human-rodent somatic hybrid cell DNA, the gene was assigned to human chromosome 4. Northern blot analyses revealed a 4.3-kilobase mRNA in a wide variety of human tissues, at the highest level in the aorta and at a substantial level in the cultured human mesangial cells. This is the first report of cloning of a gene for a member of the endothelin receptor family. The present study should give a clue to the discovery of possible disorders of the endothelin-A receptor, as well as facilitate the elucidation of the mechanisms by which the gene expression is regulated.

Amino Acid Sequence↗
PubMed1992

Non-A, non-B chronic hepatitis is chronic hepatitis C: a sensitive assay for detection of hepatitis C virus RNA in the liver.

To study the role of hepatitis C virus in non-A, non-B chronic hepatitis, 49 liver biopsy samples from 40 patients with non-A, non-B chronic hepatitis and 9 control patients were analyzed by complementary DNA/polymerase chain reaction. Two segments of the HCV genome, one in the nonstructural region and the other in the noncoding region, were amplified by two sets of primer pairs. With use of the nonstructural region primers, hepatitis C virus RNA was detected in 24 (60%) of 40 patients with non-A, non-B chronic hepatitis. Of these 40 patients, RNA was detected in 19 (70%) of 27 patients positive for antibody to hepatitis C virus and in 5 (38%) of 13 patients negative for antibody to hepatitis C virus. However, with the noncoding region primers, hepatitis C virus RNA was detected in 38 (95%) of 40 patients with non-A, non-B chronic hepatitis. Of these patients, the RNA was detected in 26 (96%) of 27 patients positive for antibody to hepatitis C virus and also in 12 (92%) of 13 patients positive for antibody to hepatitis C virus. Hepatitis C virus RNA was not detected in any of the control patients. Sequence analysis showed homology between our samples and the prototype to be only 66% to 77% in the nonstructural region but 99% to 100% in the noncoding region. We conclude that almost all patients with non-A, non-B chronic hepatitis in Japan are currently infected with hepatitis C virus, regardless of the presence or absence of antibody to hepatitis C virus.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1992

Nucleotide sequences of 5-1-1 of hepatitis C virus in patients with chronic liver disease.

The discovery of hepatitis C virus (HCV) has led to the development of an assay against a viral peptide (C100-3), which is now used worldwide. It has been shown that the majority of HCV-infected individuals are positive for the antibody. However, there are patients who are repeatedly seronegative for the antibody despite the presence of HCV RNA in the serum. The nucleotide sequences of 5-1-1 (a major epitope of C100-3) obtained from five antibody-positive patients and five negative patients with chronic liver disease were studied. The nucleotide identities of the seropositive and seronegative patients with HCV prototype sequence were 80.6% and 81.8%, respectively, not showing much difference in the nucleotide sequence of the 5-1-1 region. Moreover, no marked differences were noted in the deduced amino acid residues and the hydropathy profiles between the two groups. These data suggest that absence of the antibody in HCV carriers are not due to variations of major epitopes but are probably due to immunological incompetence against the synthetic C100-3 peptide.

Amino Acid Sequence↗
PubMed1992

Characterization of natriuretic peptide receptors in cultured cells.

To elucidate physiological and clinical implications of the natriuretic peptide family, the expression of receptors for natriuretic peptides has been examined in cultured cells (a rat pheochromocytoma cell line [PC12], bovine endothelial cells, rat aortic smooth muscle cells, human mesangial cells, and a porcine kidney epithelial cell line [LLC-PK1]) by Northern blot analysis and cyclic GMP production method for the ANP-A and ANP-B receptors and by Northern blot analysis and binding assay for the clearance receptor. The ANP-A receptor was predominantly expressed in PC12 cells, bovine endothelial cells, and LLC-PK1 cells but was barely expressed in rat aortic smooth muscle cells and human mesangial cells. By contrast, the ANP-B receptor was the major subtype of the biologically active receptors in rat aortic smooth muscle cells and human mesangial cells. Only a small amount of the ANP-B receptor was detected in PC12 cells, bovine endothelial cells, and LLC-PK1 cells. The clearance receptor was abundantly expressed in rat aortic smooth muscle cells and human mesangial cells and was also present in bovine endothelial cells, but it was undetectable in PC12 cells and LLC-PK1 cells. These results demonstrate that the expression of three natriuretic peptide receptors varies from cell to cell, which is relevant to cell- or tissue-specific action of the natriuretic peptide family.

Animals↗
PubMed1992

Human C-type natriuretic peptide. Characterization of the gene and peptide.

We isolated the human C-type natriuretic peptide gene and identified the peptide in the brain. The human C-type natriuretic peptide gene appeared to be composed of at least two exons and one intron. In the 5'-flanking region, there is an array of cis elements (an inverted CCAAT box, two GC boxes, and a cyclic AMP response element-like sequence) that is not present in upstream sequences of the atrial and brain natriuretic peptide genes. Analysis of the deduced amino acid sequence revealed that human prepro C-type natriuretic peptide comprises 126 amino acids and that the C-terminal 22-residue peptide (G-L-S-K-G-C-F-G-L-K-L-D-R-I-G-S-M-S-G-L-G-C) preceded by Lys-Lys is identical to the porcine counterpart. However, replacement of two amino acids took place in the C-terminal 53-residue sequence, corresponding to another endogenous form of the peptide. Reverse-phase high-performance liquid chromatography coupled with a radioimmunoassay for C-type natriuretic peptide demonstrated that it occurs in the human brain. C-type natriuretic peptide-like immunoreactivity was detected in discrete regions of the human brain, and its level was 10-fold higher than the atrial and brain natriuretic peptide levels, raising the possibility that C-type natriuretic peptide is the major natriuretic peptide in the human brain.

Amino Acid Sequence↗
PubMed1992

Phenotype-related alteration in expression of natriuretic peptide receptors in aortic smooth muscle cells.

To elucidate the physiological and pathophysiological roles of the natriuretic peptide family in vascular smooth muscle cells, in which the natriuretic peptide family is implicated in growth inhibition as well as vasorelaxation, we have examined the phenotype-related expression of three kinds of natriuretic peptide receptors in rat aortic smooth muscle cells. The expression of natriuretic peptide receptors at the mRNA level was studied by Northern blot hybridization, and the expression at the protein level was determined by the cGMP production method and receptor binding assay. In intact aortic media, atrial natriuretic peptide (ANP)-A receptor mRNA and ANP-B receptor mRNA were detected, and the potency of cGMP production by ANP was at least two orders of magnitude stronger than that by C-type natriuretic peptide. Clearance receptor mRNA was undetectable, and only a small amount of the clearance receptor was detected by the binding assay in intact aortic media. By contrast, in cultured aortic smooth muscle cells at the first, fifth, and 17th passages, the ANP-B receptor mRNA level markedly increased; meanwhile, the expression of the ANP-A receptor mRNA became undetectable. C-type natriuretic peptide was one order of magnitude more potent than ANP in cGMP production in cultured aortic smooth muscle cells. The clearance receptor density and its mRNA level increased tremendously in these cultured cells. These results demonstrate that the marked phenotype-related alteration occurs in the expression of natriuretic peptide receptors in rat aortic smooth muscle cells.

Actins↗
PubMed1992

Serum secretory leukoprotease inhibitor levels to diagnose pneumonia in the elderly.

In pneumonia in the elderly, one occasionally encounters difficulties in evaluation with respect to both clinical observation and treatment. Thus a simple serum indicator is indicated. We measured secretory leukoprotease inhibitor (SLPI) concentrations in sera to see whether this can provide a useful indicator for pneumonia, especially in the elderly. Serum samples from patients over 65 yr of age, with (n = 54) or without (n = 87) pneumonia, and from healthy, young (n = 16) and aged (n = 188) control subjects were assayed using ELISA for human SLPI. Comparisons were made between groups with clinical diagnoses of either definite or probable pneumonia and among cases with various other respiratory diseases, including bronchial asthma, chronic obstructive pulmonary disease, and lung cancer. The mean SLPI concentration in patients with pneumonia was significantly higher than in patients without pneumonia or in healthy controls. The data suggest that the measurement of SLPI can provide a useful indicator for pneumonia to be used in clinical evaluation.

Aged↗
PubMed1992

Variations in codons 84-101 in the core nucleotide sequence correlate with hepatocellular injury in chronic hepatitis B virus infection.

Individuals with chronic hepatitis B virus (HBV) infection are generally divided into asymptomatic healthy carriers and patients with chronic liver disease. Several studies have suggested that the hepatitis B core antigen could be an immunological target of cytotoxic T lymphocytes (CTL). To investigate the possible pressure site from CTL, the entire core region of HBV DNA was sequenced in 30 subjects (10 asymptomatic healthy carriers and 20 patients with chronic liver disease). No significant changes in the nucleotide sequence and deduced amino acid residue were noted in the 10 healthy carriers. In contrast, a cluster of changes in a small segment of 18 amino acids (codons 84-101 from the start of the core gene) was found in 15 of the 20 chronic liver disease patients. All these 15 patients had advanced liver diseases (chronic active hepatitis and cirrhosis), whereas only mild liver disease (chronic persistent hepatitis) was found in the five patients without mutations. These data suggest that the region with mutation clustering is the major target of CTL, and that the mutations evolve under the pressure of immune selection.

Adult↗
PubMed1992

Receptor selectivity of natriuretic peptide family, atrial natriuretic peptide, brain natriuretic peptide, and C-type natriuretic peptide.

To elucidate the ligand-receptor relationship of the natriuretic peptide system, which comprises at least three endogenous ligands, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP), and three receptors, the ANP-A receptor or guanylate cyclase-A (GC-A), the ANP-B receptor or guanylate cyclase-B (GC-B), and the clearance receptor (C-receptor), we characterized the receptor preparations from human, bovine, and rat tissues and cultured cells with the aid of the binding assay, Northern blot technique, and the cGMP production method. Using these receptor preparations, we examined the binding affinities of ANP, BNP, and CNP for the C-receptor and their potencies for cGMP production via the ANP-A receptor (GC-A) and the ANP-B receptor (GC-B). These analyses revealed the presence of a marked species difference in the receptor selectivity of the natriuretic peptide family, especially among BNPs. Therefore, we investigated the receptor selectivity of the natriuretic peptide family using the homologous assay system with endogenous ligands and receptors of the same species. The rank order of binding affinity for the C-receptor was ANP greater than CNP greater than BNP in both humans and rats. The rank order of potency for cGMP production via the ANP-A receptor (GC-A) was ANP greater than or equal to BNP much greater than CNP, but that via the ANP-B receptor (GC-B) was CNP greater than ANP greater than or equal to BNP. These findings on the receptor selectivity of the natriuretic peptide family provide a new insight into the understanding of the physiological and clinical implications of the natriuretic peptide system.

Animals↗
PubMed1992

Serum propeptide and intact molecular osteocalcin in normal children and children with growth hormone (GH) deficiency: a potential marker of bone growth and response to GH therapy.

To establish a sensitive marker for bone formation we have developed a sandwich enzyme-linked immunosorbent assay for intact osteocalcin (OC) and its propeptide. Serum levels of these peptides were studied in 185 normal children, aged 4-15 yr, and in 23 GH-deficient children treated with GH. The serum levels of the propeptide in normal prepubescent children were 1.43 +/- 0.23 (mean +/- SE) micrograms/L in boys and 1.53 +/- 0.23 micrograms/L in girls. The peak value occurred at the age of 13 yr in boys (2.91 +/- 0.42 micrograms/L) and 11 yr in girls (2.34 +/- 0.34 micrograms/L). The serum intact OC levels in prepubescent boys and girls were 18.8 +/- 2.1 and 20.7 +/- 2.1 micrograms/L, respectively, and these levels increased to 41.0 +/- 3.7 micrograms/L in boys aged 13 yr and to 27.0 +/- 2.5 micrograms/L in girls aged 11 yr. In the GH-deficient patients, a 2.3-fold increase in the propeptide level and a 1.7-fold increase in the intact OC level was observed after 1 month of GH therapy. Serum propeptide and intact OC levels after 1 month of GH therapy correlated with the growth response after 12 months of GH therapy (r = 0.660 and P < 0.01, for propeptide; r = 0.537 and P < 0.01 for intact OC). These results show that since both propeptide and intact OC in serum were increased when the growth rate was elevated, these peptides are sensitive markers of bone formation. Serum levels of these peptides, particularly propeptide, after 1 month of GH therapy might be a helpful predictor of the growth response to long term GH therapy.

Adolescent↗
PubMed1992

[Antipyretic effects of traditional Chinese medicines in bacterial endotoxin-induced febrile rabbits].

The antipyretic effects of oral administration of eight traditional Chinese medicines (dried extracts) were tested in febrile rabbits injected with bacterial pyrogen, lipopolysaccharide (LPS) 0.05 micrograms/kg (i.v.). The traditional Chinese medicines were given 0.6-2 g/10 ml/kg (p.o.) simultaneously with LPS. The most potent antipyretic effect was observed in Dai-jyoki-to (Ta-chen-chi-tang). The moderate antipyretic effects were observed in Toki-syakuyaku-san (Tang-kuei-shao-yao-san) and Syo-saiko-to (Hssiao-chai-hu-tang). Koso-san (Hsiang-su-san), Oren-gedoku-to (Huang-lien-chieh-tu-tan), Gorei-san (Wu-ling-san), Kakkon-to (Ko-ken-tang) and Byakkoka-ninjin-to (Pai-hu-chia-jen-sheng-tang) showed no effects.

Animals↗
PubMed1992

[Usefulness and safety of bunazosin hydrochloride in neurogenic bladder after prolonged administration].

Bunazosin hydrochloride (Ea-0643), a selective alpha 1-blocker, was administered to 14 patients with neurogenic bladder over prolonged periods of time in order to determine its efficacy and safety. Subjective symptoms were classified into 4 grades, and their response assessed after 12 weeks of treatment. The proportion of patients showing improvement by at least one grade was 50.0% for retarded urination, 16.7% for prolonged urination, 25.0% for urinary stream condition, 25.0% for abdominal pressure at voiding, and 28.6% for residual urine. Objective symptoms were also assessed after 12 weeks of treatment, and a statistically significant improvement was recognized in the volume of spontaneously voided urine, the maximum and mean flow rates on uroflowmetry. It should be noted that both of those flow rates had improved significantly only 2 weeks into the treatment. The degree of improvement in subjective and objective symptoms and the degree of general improvement were all higher at week 12 than at week 2 of treatment. Current knowledge of the mechanism of action of this drug, coupled with the observations made in this study, suggests that, once it has improved the urodynamics, it exhibits a sustained effect for prolonged periods of treatment. However, further studies are warranted concerning the mechanisms of the pharmacological action of the drug from a pathological viewpoint. The proportion of patients in whom Ea-0643 was judged to be useful at 12 weeks of treatment was 41.7%, but when the assessment of 'slightly useful' was taken into consideration, the usefulness rate rose as high as 91.7%. Stomatitis was observed in only one case as a side effect of this drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic alpha-Antagonists↗
PubMed1992

Sandwich immunoassay for intact human osteocalcin.

To overcome the problems of limited-region specificity associated with conventional radioimmunoassay (RIA), we developed a sandwich enzyme immunoassay (EIA) for intact human osteocalcin (hOC). For this EIA we used antibodies to the N- and C-terminal regions of hOC that were raised against an N-terminal 20-residue peptide and a C-terminal 7-residue peptide, both synthetic. Immunoassay profiles of tryptic digests of hOC and serum from patients with renal failure, fractionated by reversed-phase HPLC, facilitated direct demonstration of the region specificity of this method. A preliminary study of serum osteocalcin concentrations in patients with renal failure further confirmed this specificity, showing lower positive rates obtained by this method than by conventional RIA. The cross-reactivity data of hOC with bovine and rat osteocalcins by the sandwich method indicated its species specificity. These studies demonstrate the superior specificity of this sandwich EIA compared with conventional RIA and thus confirm its potential diagnostic superiority.

Adult↗
PubMed1991

Augmented secretion of brain natriuretic peptide in acute myocardial infarction.

In order to elucidate biosynthesis and secretion of natriuretic peptides in the early phase of acute myocardial infarction (AMI), we measured the plasma level of brain natriuretic peptide (BNP), a novel cardiac hormone secreted from the ventricle, in patients with AMI and compared with that of atrial natriuretic peptide (ANP). The plasma level of BNP increased rapidly (within hours from the onset of AMI) and markedly (greater than 100 times the normal level) as compared to that of ANP. The plasma ANP level correlated with pulmonary capillary wedge pressure (PCWP), whereas the plasma BNP level did not correlate with PCWP but highly correlated inversely with cardiac index. These results indicate that BNP is secreted from the heart much more acutely and prominently than ANP in the early phase of AMI, in association with left ventricular dysfunction.

Adult↗
PubMed1991

Resolution of acute hepatitis C after therapy with natural beta interferon.

To test whether interferon can prevent acute non-A, non-B hepatitis from becoming chronic, a prospective controlled trial was conducted in 25 patients; 11 were treated for an average of 30 days with a mean of 52 megaunits of interferon and 14 acted as controls. 4 patients in the treatment group who continued to have raised serum aminotransferase concentrations after a year's follow-up were given a second course of interferon. Follow-up at 3 years has revealed that all but 1 of those treated showed normal serum aminotransferase, whereas only 3 controls showed such change (p less than 0.02). Serum hepatitis C virus RNA became undetectable in 10 of 11 treated and in only 1 of 12 control patients, which suggests that interferon prevents the progression of acute non-A, non-B hepatitis to chronicity by eradicating HCV.

Acute Disease↗
PubMed1991

Cloning and expression of human endothelin-1 receptor cDNA.

We isolated a human endothelin-1 (ET-1) receptor cDNA from a human placenta cDNA library. The cDNA encodes a 427-amino acid protein with seven putative transmembrane domains. The rank order of the binding to the receptor expressed in COS-7 cells was: ET-1 greater than or equal to ET-2 much greater than ET-3. The receptor expressed in Xenopus oocytes showed a potent electrophysiological response to 1 x 10(-7) M ET-1 under voltage clamp at -60 mV, while a much weaker response was produced by 1 x 10(-7) M ET-3. Northern blot analysis with RNA from human tissues revealed a single band with a size of 4.3 kb in a wide variety of human tissues, especially highly in the blood vessel.

Amino Acid Sequence↗