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J Aikawa

Publications and source records attributed to J Aikawa.

At least 55 records · Page 3Linked to original sources
PubMed1991

Vascular smooth muscle relaxation by alpha 1-adrenoceptor blocking action of denopamine in isolated rabbit aorta.

We investigated the mechanism of vascular relaxation by denopamine (Deno), an oral positive inotropic agent that has selective beta 1-adrenergic action. Deno relaxed, dose-dependently (0.1-30 microM), ring segments of rabbit aorta, which were partially precontracted with 1 microM phenylephrine (Phe) or norepinephrine (NE), but did not relax those precontracted with 5 microM prostaglandin F2 alpha or 40 mM K+. The relaxation was not significantly inhibited by pretreatment with 10 microM propranolol or metoprolol. Deno produced parallel shifts in concentration-response curves to Phe, but this was not true for clonidine. The Schild plot analysis resulted in a linear regression of a slope of 1.075 +/- 0.063, which was not significantly different from unity, and the pA2 value of Deno against Phe was 5.57 +/- 0.02. The specific binding of [3H]prazosin to a rabbit aorta membrane preparation was displaced in a concentration-dependent manner by the simultaneous addition of Deno. The slope of a Hill plot was not significantly different from unity (1.102 +/- 0.147). The pK1 value for Deno calculated from the displacement curve was 5.29 +/- 0.17, which was not significantly different from the pA2 value of Deno. In conclusion, vascular smooth muscle relaxation by Deno was mediated by the blocking effect of alpha 1-adrenoceptors. Thus, these findings suggest that Deno may be effective in the treatment of congestive heart failure because it elicits a positive inotropic effect by beta 1-adrenergic action and vasodilation by alpha 1-adrenergic blocking action.

Adrenergic alpha-Antagonists↗
PubMed1990

Effects of glycosylation on the secretion and enzyme activity of Mucor rennin, an aspartic proteinase of Mucor pusillus, produced by recombinant yeast.

The Mucor rennin gene encoding a prepro form of the fungal aspartic proteinase from Mucor pusillus was expressed under the control of the yeast GAL7 promoter in Saccharomyces cerevisiae. The mature M. pusillus rennin secreted efficiently by yeast was a highly glycosylated protein. Analysis by a combination of site-directed mutagenesis of each of the three possible glycosylation sites and treatment of the secreted M. pusillus rennins with endo-beta-N-acetylglucosaminidase H revealed that the mature yeast M. pusillus rennin contained two asparagine-linked glycosylation sites among the three possible glycosylation sites. A mutation of the 2 glycosylated asparagine residues of M. pusillus rennin resulted in significant decreases in the level of secretion by yeast cells. In addition, the extent of glycosylation of M. pusillus rennin was found to affect the enzyme properties such as milk-clotting and proteolytic activities.

Acetylglucosaminidase↗
PubMed1990

Type 4 renal tubular acidosis (subtype 2) in a patient with methylmalonic acidaemia.

A 10-month-old male infant with vitamin B12 non-responsive methylmalonic acidaemia is reported. Laboratory results revealed hyperkalaemic, hyperchloraemic, metabolic acidosis with slight azotaemia. The urinary pH decreased (below 5.5) to compensate for acidaemia. Levels of plasma renin activity and plasma aldosterone concentration were low. The renal biopsy showed tubulo-interstitial nephritis. We suggested the diagnosis of type 4 renal tubular acidosis, subtype 2, i.e. hyporeninaemic hypoaldosteronism. We suggest that chronic renal disease may be a common complication of methylmalonic acidaemia.

Acidosis, Renal Tubular↗
PubMed1990

Vascular smooth muscle relaxation by endothelium-dependent beta 1-adrenergic action.

1. Norepinephrine (NE) (10(-5) M) in rabbit aorta relaxed ring segments with endothelium precontracted with 10(-6) M NE, but not segments without endothelium. 2. The relaxation was inhibited with metoprolol and methylene blue, but not inhibited with yohimbine and indomethacin. 3. NE (10(-5) M) significantly elevated tissue c-GMP levels in segments with endothelium. 4. These studies suggest that the vascular relaxation by high doses of NE is mediated by the release of endothelium-derived relaxing factor (EDRF) induced by the stimulation of beta 1-adrenoceptor.

Animals↗
PubMed1990

The prepro-peptide of Mucor rennin directs the secretion of human growth hormone by Saccharomyces cerevisiae.

An aspartic proteinase, Mucor pusillus rennin (MPR), of filamentous fungus Mucor pusillus, is efficiently secreted from a transformant of Saccharomyces cerevisiae containing the intact MPR gene. To test the usefulness of the MPR leader peptide in secretion of heterologous proteins from yeast cells, several plasmids encoding the fusion proteins composed of different parts of the NH2-terminal region of prepro-MPR and human growth hormone (hGH) were constructed. The parts of the leader peptide upstream of hGH were the whole prepro-peptide following the NH2-terminal region of mature MPR in JGH1, the intact pre-sequence and a part of the pro-sequence in JGH2, and the putative signal sequences of the NH2-terminal 18 and 22 amino acids in JGH3 and JGH7, respectively. When the hGH genes fused to these leader sequences were expressed in yeast cells under the control of the yeast GAL7 promoter, proteins of various sizes immunoreactive with the anti-hGH antibody were secreted into the medium. Among the plasmids mentioned above, JGH2 directed the greatest secretion of the protein of 23 kilodaltons in size, which contained the expected NH2-terminal amino acid sequence of an additional eight amino acids derived from the pro-peptide of MPR. The addition of the GAL10 terminator downstream of the hGH gene in JGH2 resulted in a greater than three- to fivefold increase in the secretion, whereas the insertion of the GAL4 gene, which is a positive regulator for the GAL system, had no significant effect. The improved yield of the total protein of hGH secreted into the medium reached approximately 10 mg/liter.

Amino Acid Sequence↗
PubMed1989

Secretion by yeast of the zymogen form of Mucor rennin, an aspartic proteinase of Mucor pusillus, and its conversion to the mature form.

The Mucor rennin gene encoding a prepro-form of the fungal aspartic proteinase from Mucor pusillus was expressed under the control of the yeast GAL7 promoter in Saccharomyces cerevisiae. An inactive zymogen of the enzyme with the 44-amino-acid pro-sequence was identified in the medium during the initial stage of cultivation. Processing of the purified zymogen to the mature enzyme proceeded autocatalytically under the acidic conditions. The rate of processing was accelerated by an increase in the concentration of the zymogen or addition of the mature enzyme. The in vitro processing was inhibited by inhibitors for the aspartic proteinases. The zymogen with no proteinase activity due to a mutation at the active site residue, Asp, was still processed at a relatively slower rate in a wild-type strain of yeast, but no processing occurred in the pep4-3 mutant strain of S. cerevisiae deficient in yeast proteinase A. Thus, Mucor rennin is excreted in a form of zymogen, which is then processed in the yeast secretion pathway mainly by the autocatalytic proteolysis but, alternatively, by a proteinase of yeast.

Amino Acid Sequence↗
PubMed1989

Computed tomography, magnetic resonance imaging, positron emission tomography and evoked potentials at early stage of adrenoleukodystrophy.

An 8 year-old-boy with adrenoleukodystrophy (ALD) was subject to an x-ray computed tomography (CT) scan, magnetic resonance imaging (MRI), positron emission tomography (PET) using 18F-fluorodeoxy glucose and evoked potential studies, about 3 months after the onset of neurologic symptoms. A CT showed decreased radiodensity over the white matter of both occipital lobes, and high density areas on the periventricular space. No contrast enhancement was observed around the low dense white matter, while occipital grey matter seemed to be almost normal. MRI demonstrated a larger and more obvious lesion of prolonged T2 relaxation time which was 170-250 msec than that detected by CT scan. The PET demonstrated wide and severe hypometabolism for glucose over the grey and the white matter of bilateral occipital lobes. The visual evoked potential (VEP) was scarcely elicitable, while the auditory brainstem response (ABR) and short latency somatosensory evoked potential (SSEP) was normal. These imaging studies suggest that extensive and profound demyelination exists in the occipital white matter. For detection of demyelinizing process, MRI may be more effective than CT in this disorder. The PET study revealed that there may have been an abnormality of the grey matter as well as the white matter in the occipital lobe. The VEP disappeared in the relatively early stage. The brainstem may not be involved at such early stage in light of normal ABR and SSEP.

Adrenoleukodystrophy↗
PubMed1989

[Two siblings of Leber's congenital amaurosis with an increase in very long chain fatty acid in blood: relationship between peroxisomal disorders and Leber's congenital amaurosis].

We reported two siblings of Leber's congenital amaurosis associated with increased level of very long chain fatty acid (VLCFA) in blood. Case 1, a 3 1/2-year-old boy had congenital blindness, severe psychomotor retardation, hepatomegaly, profound hypotonia, loss of deep tendon reflexes, muscular atrophy and weakness, and non-convulsive status epilepticus characterized by a sudden respiratory failure, and also showed a flat electroretinogram, non-pigmentary retinal degeneration, severe atrophy of the brain stem and cerebellum, hepatic fibrosis, decreased motor and sensory conduction velocities and atlanto-axial instability. Sural nerve biopsy revealed severely decreased number of total myelinated fibers without remarkable demyelination or remyelination. Case 2, an elder sister of case 1, with pigmentary retinal degeneration, hepatomegaly and pericarditis had died at 3 months. Autopsy revealed hypomyelination and heterotopy of the cerebral white matter, hepatic fibrosis, renal microcysts and normal adrenal cytoarchitecture. In case 1, the level of VLCFA was increased twofold and sevenfold of controls in serum and in red cell membrane, respectively. Phytanic or trihydroxycholestanoic acid was not detected in the serum and bile. Normal shaped peroxisomes were definitely recognized in biopsied liver by means of electronmicroscopic histochemistry. From the above findings, these patients was thought to be a new variant of peroxisomal disorders relating to degradation of VLCFA, other than Zellweger syndrome, infantile Refsum disease and infantile adrenoleukodystrophy. It was concluded that peroxisomal functions should be studied in cases of Leber's congenital amaurosis.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1987

Isolation of dermatan sulfate with high heparin cofactor II-mediated thrombin-inhibitory activity from porcine spleen.

We prepared dermatan sulfate specimens from various porcine tissues, and compared their heparin cofactor II-mediated thrombin-inhibitory activities and chemical natures, including disaccharide composition. Electrophoresis of the specimens on cellulose acetate membrane indicated that spleen dermatan sulfate was the most acidic of the dermatan sulfates prepared from the various porcine tissues. Analysis of the disaccharide units of the dermatan sulfate specimens by high-performance liquid chromatography revealed that spleen dermatan sulfate was rich in 4,6-di-O-sulfated N-acetylgalactosamine residues as compared with those of the other tissues. Spleen dermatan sulfate exhibited the highest thrombin-inhibitory activity, which may be related to its high content of the disulfated N-acetylgalactosamine residue.

Animals↗
PubMed1987

Isolation and characterization of fibronectin-binding proteoglycan carrying both heparan sulfate and dermatan sulfate chains from human placenta.

A proteoglycan was isolated from the human placenta by procedures including affinity chromatography with fibronectin immobilized on agarose. The glycosaminoglycan chains were found to be composed of heparan sulfate (86%) and dermatan sulfate (14%). The average molecular weights were estimated to be 1.8 X 10(5) for heparan sulfate and 1.2 X 10(5) for dermatan sulfate. Mouse monoclonal antibodies HS42 and HS47 were prepared against the proteoglycan, and examination of the specificity of these antibodies indicated that they recognized the core protein portion. The binding specificity, as studied by the solid phase enzyme-linked immunoassay with monoclonal antibody HS47, indicated that the proteoglycan bound to solid phase fibronectin and to laminin, but not to collagen types I, II, and IV or gelatin. Competitive immunoassays suggested that the proteoglycan bound weakly to the liquid phase-soluble fibronectin. These studies also indicated that the core protein was involved in the interaction between the proteoglycan and solid phase fibronectin. The ubiquitous distribution of this proteoglycan in the human tissues was demonstrated by the immunohistochemical method and thus suggested its important role in the tissue organization and function.

Amino Acids↗
PubMed1987

Isolation and characterization of a mucin-type glycoprotein from the lung lavage of a patient with alveolar proteinosis.

A high molecular weight glycoprotein was isolated from the lavage fluid of a patient with alveolar proteinosis by gel chromatography with Sepharose CL-4B. The glycoprotein gave a single band stainable with alcian blue and with periodate-Schiff reagent on the cellulose acetate membrane electrophoresis. The glycoprotein did not penetrate 3.3% polyacrylamide gel but moved into 1% agarose gel as a periodate-Schiff positive single band, when electrophoresed in the presence of sodium dodecyl sulfate. The chemical analysis and the results of the beta-elimination reaction showed the presence of O-linked carbohydrate chains characteristic for a mucin-type glycoprotein. These data provide the first characterization of a mucin-type glycoprotein isolated from lung in pulmonary alveolar proteinosis.

Amino Acids↗
PubMed1986

Isolation and characterization of chondroitin sulfate proteoglycans from porcine thoracic aorta.

A chondroitin sulfate proteoglycan fraction was prepared from the 3 M MgCl2 extract of porcine aortas by DEAE-cellulose chromatography, followed by gel filtration through Sepharose CL-4B. Affinity chromatography of the fraction with antithrombin III-agarose yielded two chondroitin sulfate proteoglycans of a non-binding (proteoglycan IA) and binding (proteoglycan IB) nature. Proteoglycans IA and IB were different from each other in molecular size, in proportion of the protein relative to the polysaccharide portion, and in size of the chondroitin sulfate chain. They were also distinguished immunochemically. These data indicate that the intima-media of the aorta contains at least two distinct species of chondroitin sulfate proteoglycan.

Amino Acids↗
PubMed1986

Liquid-chromatographic determination of urinary glycosaminoglycans for differential diagnosis of genetic mucopolysaccharidoses.

Glycosaminoglycans in urine from patients with various mucopolysaccharidoses were digested with chondroitin ABC lyase (EC 4.2.2.4) or chondroitin AC lyase (EC 4.2.2.5), then converted into fluorescent pyridylamino derivatives and analyzed by "high-performance" liquid chromatography. Chromatograms of the chondroitin ABC lyase digests of samples from nine patients with Hunter's syndrome all showed a major peak for unsaturated disaccharide-4-sulfate, derived from dermatan sulfate, and another specific but unidentified peak (peak x). All samples from patients with Hurler's and Scheie's syndromes contained another specific component (peak y), besides the disaccharide-4-sulfate. A sample from a patient with Maroteaux-Lamy syndrome showed peaks for N-acetylgalactosamine-4-sulfate and the disaccharide-4-sulfate, but neither peak x nor peak y. A sample from a patient with Morquio's disease showed a much higher ratio of the 6-sulfate to 4-sulfate than in other diseases, and N-acetylgalactosamine-6-sulfate was detected. We tentatively identified peaks x and y as the pyridylamino derivatives of 2-O-sulfo-L-idosyluronic acid 4-O-sulfo-N-acetylgalactosamine and L-idosyluronic acid 4-O-sulfo-N-acetylgalactosamine, respectively. This method may be useful in differential diagnosis.

Adolescent↗