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Biomedical subjects

M Furuya

Publications and source records attributed to M Furuya.

At least 19 recordsLinked to original sources
PubMed1992

Structural requirements of C-type natriuretic peptide for elevation of cyclic GMP in cultured vascular smooth muscle cells.

C-type natriuretic peptide (CNP), which was recently found to be a selective ligand for one of the two known natriuretic peptide receptor guanylyl cyclases (NPR-B), potently stimulates cGMP production in cultured rat vascular smooth muscle cells (VSMC) and exerts potent antiproliferative effects on the cells. To investigate the structural requirements of CNP for stimulation of cGMP accumulation via NPR-B, we prepared CNP analogs and tested them on cultured rat VSMC. Our results indicate that only the ring portion of CNP with a disulfide bond (CNP(6-22)) participates in stimulation of cGMP accumulation, especially the sequence Leu9-Lys10-Leu11 in the ring portion executes essential roles for both elevation of cGMP and selectivity of the ligand for NPR-B. We also found a good correlation between the activities of the CNP analogs for stimulation of cGMP accumulation and inhibition of DNA synthesis.

Amino Acid Sequence↗
PubMed1992

Serine-to-alanine substitutions at the amino-terminal region of phytochrome A result in an increase in biological activity.

We have used a tobacco transgenic plant system to assay the structure/function relationship of phytochrome A (phyA), a plant photoreceptor. The amino terminus of phyA from different plant species is very rich in serine residues. To investigate whether these serine residues are required for phytochrome function, the first 10 serine codons encoding amino acid residues 2-4, 10-14, 19, and 20 in the amino-terminal domain of the rice phyA gene (phyA) were changed to alanine codons. The mutant (S/A phyA), as well as the wild-type phyA cDNA, was placed under the control of the 35S promoter, and the chimeric genes were transferred into the tobacco genome by Agrobacterium-mediated transformation. Transgenic tobacco plants expressing either wild-type or S/A phyA showed similar phenotypic alterations, including dwarfism and dark-green leaves. However, hypocotyl elongation experiments revealed that transgenic seedlings expressing S/A phyA showed a higher amplitude of the red light response with respect to the inhibition of hypocotyl elongation. The observed difference is not correlated with expression levels of the transgene. The chromophore is attached to the mutant phyA apoprotein (PHY A), and the mutant photoreceptor is photoreversible, giving a difference spectrum indistinguishable from that of the rice phyA. Our results indicate that the S/A mutant has a higher biological activity as compared with the wild-type rice phyA.

Alanine↗
PubMed1992

Detection of antibodies against streptococcal peptidoglycan and the peptide subunit (synthetic tetra-D-alanyl-bovine serum albumin complex) in rheumatic-diseases.

Serum antibodies reactive with streptococcal cell wall peptidoglycan (PG) and its peptide subunit (synthetic tetra-D-alanine) were measured by enzyme-linked immunosorbent assay (ELISA) in patients with rheumatoid arthritis (RA), juvenile rheumatoid arthritis (JRA), osteoarthritis and acute rheumatic fever (RF) compared with healthy subjects. Using 'checkerboard' titrations, anti-PG antibody in human serum was detected at a concentration of PG antigen at 10 micrograms per well with serum dilutions of 1:1,000. For measurement of anti-tetra-D-alanine antibody, the antigen, (D-Ala4)31 was used at 0.5 micrograms per well and sera were diluted to 1:200. When the IgG antibody levels to the PG and the tetra-D-alanine of the sera of patients with RA, JRA and RF were compared with sera from healthy subjects, the sera of the patients had significantly higher levels than did healthy subjects. Antibody that reacted with the PG in serum was absorbed with purified group-specific C-carbohydrate (A-CHO), but A-CHO was not capable of absorbing anti-(D-Ala4)31 antibodies. Therefore, the peptide subunit should be used as antigen in order to measure the specific antibody to PG. Both anti-PG and anti-tetra-D-alanine antibody in human sera primarily belonged to the IgG2 subclass.

Adolescent↗
PubMed1992

Xeroderma pigmentosum variant associated with multiple skin cancers and a lung cancer.

A 65-year-old Japanese man with a xeroderma pigmentosum (XP) variant, XP127TO, is described. The XP127TO skin fibroblasts exhibited the typical XP variant characteristics of a 1.5-fold higher sensitivity than normal cells to the lethal effect of 254 nm ultraviolet (UV) light and the normal level of unscheduled DNA synthesis induced by 254 nm UV. Caffeine dose-dependently increased the cytotoxic effect of 254 nm UV on XP127TO cells. Clinically, the patient developed not only 3 cutaneous squamous cell carcinomas on sun-exposed areas but also an adenocarcinoma of the upper lobe of the right lung. A review of the 14 documented Japanese XP patients with nonskin malignancies indicates that the incidence of nonskin malignancy in XP patients is much lower than that of skin cancer in XP but higher than that in the general population.

Adenocarcinoma, Papillary↗
PubMed1992

The cucumber long hypocotyl mutant lacks a light-stable PHYB-like phytochrome.

A novel cDNA sequence homologous to a phytochrome B (phyB) gene that was isolated in a library from tobacco tissue has been used in an Escherichia coli expression system to raise anti-phytochrome B (anti-PHYB) polypeptide-specific monoclonal antibodies. The specificity of these antibodies has been tested by cross-reactivity against purified pea light-labile type 1 and light-stable type 2 phytochromes, with some antibodies reacting with the type 2 and none with the type 1 phytochromes. One such antibody, monoclonal mAT1, has been employed to analyze the phytochrome molecular species present in a photomorphogenic long hypocotyl (lh) mutant of cucumber. The results indicated that the mutant contains wild-type levels of the light-labile type 1 phytochrome polypeptide (PHYA), which has an apparent molecular mass of approximately 120 kD, but shows less than 1% (detection limit) of a light-stable polypeptide recognized by mAT1 in wild-type seedlings. This protein, not detectable in the lh mutant, has the properties of light-stable type 2 phytochrome, has an apparent molecular mass of 116 to 117 kD, and remains at constant levels under continuous low-fluence-rate red light. Therefore, we conclude that the lh mutant lacks at least one type 2 phytochrome-like polypeptide, most probably a phyB gene product. The correlation between the lack of this protein and the deficiency or absence of physiological responses to a light-stable phytochrome species in this mutant helps to identify the physiological roles played by the products of different subfamilies within the phytochrome gene family.

Antibodies, Monoclonal↗
PubMed1991

In vitro assembly of apophytochrome and apophytochrome deletion mutants expressed in yeast with phycocyanobilin.

Recombinant pea type I phytochrome apoprotein expressed in yeast is shown to assemble in vitro with phycocyanobilin to produce a photoreversible phytochrome-like adduct. As an initial investigation of the amino acid sequence requirements for chromophore incorporation, three phyA gene product deletion mutants were produced in yeast. Truncation of the N-terminal tail to residue 46 demonstrates that this region is not critical to bilin attachment, but a deletion mutant lacking 222 amino acids from the N terminus failed to yield holophytochrome in vitro, under the same conditions. A mutant comprising a deletion of the C terminus to residue 548 showed bilin incorporation and red/far-red photoreversibility, indicating that bilin-apophytochrome assembly still occurred even when the entire C-terminal domain was truncated.

Apoproteins↗
PubMed1991

Pharmacological activities of brain natriuretic peptides of human, porcine and rat origin.

The pharmacological activities of synthetic mammalian brain natriuretic peptides (BNP) from the human, pig and rat were examined in rats. These peptides all elicited diuresis and hypotension, relaxed isolated rat aorta, augmented cyclic GMP concentration in cultured rat vascular smooth muscle cells, and bound to the cells with a high affinity. Pig and rat BNPs were as active as atrial natriuretic peptides from the human and the rat (alpha-hANP and alpha-rANP) for the diuretic and hypotensive effects as well as for cyclic GMP augmentation, while human BNP was about 10 times less potent. Rat BNP was not as active as the other peptides in competing with the binding of [125I]alpha-hANP to rat vascular smooth muscle cells. Thus, the BNPs did not have identical pharmacological profiles although the potencies of the peptides for cyclic GMP augmentation correlated well to those for vasorelaxation.

Amino Acid Sequence↗
PubMed1991

C-type natriuretic peptide is a growth inhibitor of rat vascular smooth muscle cells.

C-type natriuretic peptide (CNP) which potently stimulates particulate guanylate cyclase activity in cultured rat vascular smooth muscle cells (VSMC) inhibited serum-induced DNA synthesis of the cells 10-fold more effectively than alpha-human atrial natriuretic peptide (alpha-hANP). The inhibitory effect of CNP was mimicked by 8-bromo-cGMP. The proliferation of VSMC was also suppressed by CNP more potently than alpha-hANP, while the peptide was less active for cGMP augmentation and for vasorelaxation than alpha-hANP in isolated rat aorta. These results suggest that CNP may be a growth regulating factor of VSMC rather than a vasodilator.

Animals↗
PubMed1991

Distribution of type I phytochrome (phyA) RNA1 and RNA2 in etiolated pea seedlings.

Four-day-old etiolated pea seedlings were divided into 11 parts along the axis, from which poly(A)+ RNA and DNA were extracted. Using a slot-blot hybridization assay, the abundance of pea type I phytochrome (phyA) poly(A)+ RNA was measured in each portion of the etiolated pea seedling. For the quantification of the phyA RNA, pea phyA RNA synthesized in vitro was used as an RNA standard. The hook region contained the highest abundance of phyA RNA (approximately 0.3 ng phyA RNA per microgram DNA) in the etiolated seedling. Two mRNAs of different length (the shorter designated as RNA1 and the longer RNA2) are produced in detectable amounts from single pea phyA in the etiolated seedling; the ratio of the abundance of phyA RNA1 to phyA RNA2 was determined in each of the 11 parts by a primer extension assay. The abundance of phyA RNA1 in the plumule and hook regions was 3-5-fold higher than that of RNA2, whereas the ratio of their abundance was approximately unity in other regions. A time course study of the abundance of both RNAs was carried out during the imbibition of seeds and indicated that the accumulation of phyA RNA1 occurred more rapidly in the cotyledons than that of RNA2 during the first day of imbibition, whereas the accumulation of phyA RNA2 increased rapidly during the second day and became as high as that of phyA RNA1 by the third day.

Base Sequence↗
PubMed1991

Structure-activity relationships of alpha-human atrial natriuretic peptide (alpha-hANP) analogs: role of charged groups in alpha-hANP.

To determine whether the addition of a methylene unit in the side chain of the Asp or Arg residue in alpha-human atrial natriuretic peptide (alpha-hANP) influences its biological activity, analogs of alpha-hANP, [Glu13]-alpha-hANP (7-28) (1), [Aad13]-alpha-hANP (7-28) (2), and [Harn]-alpha-hANP(7-28) (where n is any possible combination of 11, 14 and 27) (3-9), where the original Asp or Arg residue was replaced by a homo-amino acid, were synthesized by the solid-phase synthesis method. All the analogs were evaluated for their receptor binding, cyclic guanosine monophosphate (cGMP) accumulation activity in rat vascular smooth muscle cells (VSMC), and for vasorelaxant activity employing rat aorta. 1 and 2 were 0.9 and 0.03 times as potent as alpha-hANP (7-28), respectively, in binding. Har-containing analogs (3-9) were as potent as alpha-hANP (7-28) in binding. Among the Har-containing analogs, [Har11,14]-alpha-hANP (7-28) (6) and [Har11,27]-alpha-hANP (7-28) (7) were remarkably vasorelaxant active, being 4.2 and 5.3 times potent than alpha-hANP (7-28), respectively, in spite of relatively lower cGMP accumulation activity in the case of 7. The roles of the chargeable amino acid residues in biological activity are discussed.

Amino Acid Sequence↗
PubMed1991

Andean leishmaniasis in Ecuador caused by infection with Leishmania mexicana and L. major-like parasites.

Between 1986 and 1988, epidemiologic studies were carried out in a small rural community in an Andean region of Ecuador, where cutaneous leishmaniasis is highly endemic. A total of 25 human cases, positive for Leishmania parasites by culture and/or smear, were examined. Fourteen of the cases were in infants less than one year of age, suggesting intradomiciliary transmission of the disease. Clinically, many of these cases were similar to descriptions of "uta," a form of cutaneous leishmaniasis which occurs in Andean regions of Peru and is reported caused by L. peruviana. Of the 11 positive cultures obtained from human cases in the present study, eight were identified by molecular characterization as L. mexicana and three were identified as L. major-like. Two additional isolates of L. mexicana were also made from an infected dog and from a sand fly, Lutzomyia ayacuchensis, living in the region, thus implicating the latter species as possible reservoir and vector, respectively, of L. mexicana in this highland community. The significance and validity of recent isolates of L. major-like parasites from the New World are also discussed.

Animals↗
PubMed1991

A stimulating electrode easily attached to and detached from the phrenic nerve.

An electrode system is developed for temporary diaphragm pacing. It is divided into four parts: an electrode complex, a tube, a branch for a lead and a syringe. Stainless steel electrodes are put forward and pulled back by pressure produced by the syringe so that they can be easily attached to and detached from the phrenic nerve. Experiments show that the system works well, the nerve is successfully stimulated and no nerve damages are visually observed.

Animals↗
PubMed1990

Rapid confirmation and revision of the primary structure of bovine serum albumin by ESIMS and Frit-FAB LC/MS.

Incorrectness of the amino acid sequence of bovine serum albumin (BSA) was suggested from the observed molecular weight of BSA obtained by electrospray ionization mass spectrometry (ESIMS). Lack of a tyrosine residue in the position of 156th was found rapidly, by the combination of frit-fast atom bombardment mass spectrometry/liquid chromatography (Frit-FAB LC/MS), automated Edman degradation and tandem mass spectrometry (MS). Then it turned out that BSA is composed of 583 amino acid residues, and that its average molecular weight is not 66267.1, and it is corrected to 66430.3. Moreover the amino acid sequence of the positions of 94th and 95th was corrected to -QE- by using automated Edman degradation method.

Amino Acid Sequence↗
PubMed1990

Importance of hydrophobic residues in alpha-human atrial natriuretic peptide (alpha-hANP) for vasorelaxant activity.

To investigate the roles of the hydrophobic residues in the ANP molecule on biological activities, we synthesized a series of analogs containing various phenylalanine-homologs in position 8 or methionine-homologs in position 12. Among the analogs [pCl-Phe8]-alpha-hANP(7-28) was 4.8 times as potent as alpha-hANP(7-28) in cGMP accumulation and 3.5 times as potent in vasorelaxant activity. All the analogs showed nanomolar affinity to the receptor. In contrast, vasorelaxation and cGMP accumulation activity of the analogs ranged widely. These results suggest that these hydrophobic residues in the cyclic core are critical for vasorelaxant activity rather than for the "apparent receptor binding", and that these residues may possibly discriminate the "bioactive receptor" which is coupled to guanylate cyclase from the non-coupled receptor.

Amino Acid Sequence↗
PubMed1990

Novel natriuretic peptide, CNP, potently stimulates cyclic GMP production in rat cultured vascular smooth muscle cells.

The newly identified peptide C-type natriuretic peptide (CNP) caused only a slight elevation of cGMP in rat renal glomeruli. In contrast, CNP potently increased cGMP levels in cultured rat vascular smooth muscle cells (VSMC) and stimulated guanylate cyclase activity in the particulate fraction of the cells. The extent of maximum activation of the enzyme induced by CNP was 4-fold higher than that by human atrial natriuretic peptide (alpha-hANP) while CNP was 4- and 16-fold weaker than alpha-hANP in binding affinity for the putative receptors on VSMC and vasorelaxant activity for rat aorta, respectively. These results indicate that CNP is a potent stimulator of cGMP formation in VSMC but not in glomeruli and pharmacological feature of CNP is distinct from that of ANP.

Amino Acid Sequence↗
PubMed1990

Synthesis and biological property of alpha-human atrial natriuretic peptide analogs with a constrained or stereochemically modified cyclic moiety.

Conformationally restricted analogs of alpha-human atrial natriuretic peptide (alpha-hANP) containing L- or D-penicillamine, or D-cysteine in place of cysteine residues at positions 7 and 23 were synthesized by the liquid phase procedure. Their biological properties in the assays of receptor binding and cyclic guanosine monophosphate (cGMP) accumulation employing rat vascular smooth muscle cells (VSMC), vasorelaxant activity using rat isolated aorta were evaluated. We found that the constrained and/or stereochemically altered ring moiety generally did not influence the receptor binding activity, however, cGMP accumulation and vasorelaxant activities were quite sensitive to conformational perturbation. Furthermore, a lack of correlation between cGMP accumulation activity and vasorelaxant activity was observed. Dissociation between these activities was typical in the case of [DPen7,23]-alpha-hANP(7-28), which showed quite weak vasorelaxant activity in spite of its full cGMP accumulation and receptor binding potencies. This result suggests that cGMP accumulation alone is not sufficient to promote ANP-induced vasorelaxation, and that the other second messenger(s) may mediate this activity.

Amino Acid Sequence↗