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Biomedical subjects

T Ikeno

Publications and source records attributed to T Ikeno.

At least 55 records · Page 3Linked to original sources
PubMed1986

Effect of leupeptin, a protease inhibitor, on dopa decarboxylase and protease activities in homogenates of submandibular salivary glands from young rats.

Dopa-decarboxylase activity was high at 2-3 weeks of age, low at 5-6 weeks, and very low in adult rats; protease activity increased with age. Trypsin-like proteases, which decrease dopa-decarboxylase activity, were detected in the gland and were inhibited by a protease inhibitor, leupeptin. High concentrations (20 mg/ml) of leupeptin increased dopa-decarboxylase activity in the glands of adult rats to the level found at 5-6 weeks of age. The low activity of dopa decarboxylase in adult gland may be due in part to endogenous proteases.

Aging↗
PubMed1986

Assay of trypsin-like protease in rat submandibular saliva and gland.

Trypsin-like protease activity was high in the submandibular gland, low in the pancreas, and absent in the liver, kidney and brain of adult rats. The alpha-sympathomimetic agent, norepinephrine, induced a marked secretion of the enzyme into submandibular saliva and the remaining protease activity within the gland decreased to about 64 per cent of control levels. Six peaks of protease activity, found by isoelectric focusing in intact submandibular glands, were also detected in the saliva of norepinephrine-stimulated rats. Isoprenaline also increased the protease activity in saliva, but far less so than norepinephrine. The parasympathomimetic agent, pilocarpine, had little effect on the secretion of the enzyme into saliva.

Animals↗
PubMed1986

Purification and characterization of a trypsin-like protease in the submandibular gland of rats.

A trypsin-like protease (named RSP-V) was purified to homogeneity from rat submandibular glands by isoelectric focusing and high-performance liquid chromatography. The purified enzyme had an isoelectric point of 5.3 and an apparent molecular weight of 25,000, and consisted of two subunits with molecular weights of 19,500 and 6,000. RSP-V hydrolyzed BAEE, BAPA, and TAME, but not ATEE or BTPA. It had an optimum pH at around 10.0. RSP-V was strongly inhibited by soybean trypsin inhibitor, aprotinin, leupeptin, antipain, and benzamidine, but not by ovomucoid trypsin inhibitor, p-CMB, or iodoacetic acid. This enzyme partly resembled, but was not identical with, tonin. It was also different from kallikrein, salivain, and glandulain in rat submandibular gland. Although the physiological role of RSP-V has not yet been clarified, this enzyme inactivated dopa decarboxylase alone among catecholamine-synthesizing enzymes.

Amino Acids↗
PubMed1985

Wheat germ agglutinin inhibits the effects of nerve growth factor on the phosphorylation of proteins in PC12h cells.

Treatment of PC12h cells in tissue culture with nerve growth factor (NGF) led to an increased incorporation of [32P]orthophosphoric acid into specific proteins. The increased phosphorylation of 60,000-dalton and 20,000-dalton proteins in the 0.2% Triton X-100 detergent-soluble fraction, of 35,000-dalton protein in the 0.2% Triton X-100 detergent-insoluble fraction, and of slow migrating protein (SMP) in the nonhistone nuclear fraction was observed upon NGF treatment. On the other hand, wheat germ agglutinin (WGA) treatment of PC12h cells induced a slightly decreased phosphorylation of these NGF-responsive proteins. Incubation of cell-free extracts from PC12h cells with [gamma-32P]ATP led to the phosphorylation of a 100,000-dalton protein. In extracts from cells treated with NGF, the labeling of the 100,000-dalton protein was substantially and selectively reduced. In contrast, treatment of PC12h cells with WGA led to an increased phosphorylation of the 100,000-dalton protein in cell-free extracts. Thus, NGF and WGA showed opposite effects on the phosphorylation of specific proteins in both intact cells and cell-free extracts. In addition, it was also observed in both systems that pre- and posttreatment of PC12h cells with WGA abolished the effects of NGF on the phosphorylation and produced a phosphorylation pattern similar to that from PC12h cells treated only with WGA. In parent PC12 cells, it has been reported that the treatment of cells with WGA inhibits NGF binding to its receptors and converts the rapidly dissociating receptors to slowly dissociating receptors. Thus, WGA in conjunction with NGF, results in the practical disappearance of rapidly dissociating receptors on cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗
PubMed1984

Transport to the bloodstream of amylase following retrograde infusion of amylase into the parotid glands in the rat.

Amylase secretion into parotid saliva was increased more by isoprenaline whereas the secretion rate of parotid saliva was increased more by pilocarpine. Retrograde infusion of parotid-amylase solution into excretory ducts of the parotid gland elevated the activity of the enzyme in the serum. Direct evidence that retrogradely-infused amylase reaches the blood from the parotid gland was obtained using amylase prepared from Bacillus subtilis. Pretreatment with pilocarpine accelerated the release of amylase into the blood. The elevation of intraductal pressure may be the primary mechanism for the release of amylase into the blood from the parotid glands.

Amylases↗
PubMed1983

Activities of sulfatases for the degradation of acidic glycosaminoglycans in cultured skin fibroblasts from two siblings with multiple sulfatase deficiency.

Cultured skin fibroblasts from two siblings with multiple sulfatase deficiency (MSD) were assayed for the activities of sulfatases known to degrade acidic glycosaminoglycans (AGAG). There were iduronate sulfatase, arylsulfatase B, heparan sulfate (HS) sulfatase, N-acetylgalactosamine-6-sulfate sulfatase, HS-derived N-acetylglucosamine-6-sulfate sulfatase, and two keratan sulfate (KS)-derived N-acetylglucosamine-6-sulfate sulfatases. The activities of sulfatases required for the degradation of HS were reduced to a greater extent than those for the degradation of dermatan sulfate (DS), and those of sulfatases associated with basic defect of Morquio disease type A were moderately decreased or normal. On the other hand, urinary excretion of AGAG in both patients was increased about 10-fold compared to controls, and especially, the excretion of HS and DS was increased about 150-fold and 50-fold, respectively. Keratan sulfate was not detected. The results suggest that in patients with MSD the degradation of HS might be affected to a greater extent than that of DS.

Cells, Cultured↗
PubMed1983

Quantitative changes in amylase activity in the salivary glands, pancreas, saliva, and serum after administration of isoproterenol, pilocarpine, and acetylcholine.

Amylase activity in various tissues--i.e., submandibular/sublingual and parotid glands, the pancreas, saliva, and serum--in rats was measured after injection of isoproterenol, pilocarpine, and acetylcholine. All agents reduced amylase activity in the parotid gland and increased the enzyme activity in the submandibular/sublingual glands, in saliva and serum.

Acetylcholine↗
PubMed1983

Characterization of keratan sulfate isolated from liver affected by Morquio syndrome.

Chemical structures of keratan sulfate (KS) isolated from the liver affected by Morquio syndrome type A (classical type) were investigated. In the KS from Morquio syndrome liver, the molar ratios of hexose, total sulfate, N-sulfate and sialic acid to hexosamine were 5.07, 0.90, 0.18 and 0.08, respectively, and about 10% of hexosamine consisted of galactosamine. The KS resulted in a production of oligosaccharides of relatively larger size after digestion with keratanase, as compared with bovine corneal KS. These findings strongly suggest that KS accumulated in the liver affected by Morquio syndrome may be derived from bony KS.

Animals↗
PubMed1982

Amylase released from the parotid gland by pilocarpine elevates the enzyme activity in the submandibular and sublingual glands of rats.

Stimulation by pilocarpine led to a marked increase in amylase activity in the submandibular and sublingual glands and serum, and resulted in a considerable depletion of the enzyme in the parotid gland and pancreas of rats. Parotidectomy reduced these pilocarpine effects. It is concluded that amylase released by pilocarpine from the parotid gland but not from the pancreas elevated the enzyme activity in the submandibular and sublingual glands.

Amylases↗
PubMed1982

Mechanisms of increase in amylase activity in rat submandibular and sublingual glands after administration of pilocarpine.

The increase in parotid rather than pancreatic-type amylase activity in the submandibular and sublingual glands of rats caused by administration of pilocarpine was abolished or diminished when pilocarpine was injected into rats which had been parotidectomized, sympathectomized by superior cervical ganglionectomy or pretreated with reserpine. These results suggest that the increases in amylase activity in the submandibular and sublingual glands by pilocarpine are not due to increase in enzyme synthesis, but to uptake of enzyme released into the blood in large quantities from the parotid gland and that the release from the parotid gland by pilocarpine is primarily mediated by sympathetic nerves.

Amylases↗
PubMed1982

Acidic glycosaminoglycans and gangliosides in the brains from four patients with genetic mucopolysaccharidosis.

Acidic glycosaminoglycans (GAGs) and gangliosides were analyzed in the brains from control fetuses, fetal Hurler syndrome, control children and three patients affected by genetic mucopolysaccharidosis (Hurler, Hunter and Morquio syndromes). GAGs contents in the brains from patients with Hurler and Hunter syndromes were approximately 1.5-3.0-fold greater as compared with those controls, and most of the GAGs were much more degraded than those from controls. Dermatan sulfate (DS), which was not identified in the control brains, comprised about 20--40% of the total GAGs. On the other hand, GAGs content and molecular weight distribution in the brain from the patient affected by Morquio syndrome were similar to those in the control brains. GAGs content in the brain from fetal Hurler syndrome was also 2.0-fold greater and DS, which was not detected in the control fetal brains, comprised 1.6% of the total GAGs. However, the molecular weight distribution of the GAGs was similar to those of the control fetal brains. The total amount of the brain gangliosides in all patients assayed here was similar to those in the control brains. However, a greater amount of GM1- and Gm2-gangliosides was observed in the brains from patients with Hurler and Hunter syndromes.

Adolescent↗
PubMed1981

Prenatal diagnosis of Hurler's syndrome--biochemical studies on the affected fetus.

A prenatal diagnosis of Hurler's syndrome was made in a pregnancy at risk in a family with two affected children. The fetus was diagnosed as having Hurler's syndrome on the basis of a deficiency of alpha-L-iduronidase in the cultured amniotic cells. The glycosaminoglycans (GAG) content in the supernatant of the amniotic fluid was increased about 1.5 fold compared with that in the control, and increases of heparan sulfate and dermatan sulfate were observed on electrophoresis. The diagnosis could be confirmed by the deficiencies of alpha-L-iduronidase in the liver and brain from the affected fetus. GAG content in the liver from the affected fetus was increased approximately 10 fold as compared with that in the control fetal liver, and most of the GAG were degraded. The GAG content was observed to be increased two fold in the brain, and dermatan sulfate, which was not detected in normal fetal brain, was identified. beta-Galactosidase activities in the affected liver and brain were decreased to 30-50% of the control, and an altered hexosaminidase A was also observed in the liver.

Amniotic Fluid↗
PubMed1981

The receptor-mediated activation of tyrosine hydroxylation in the superior cervical ganglion of the rat.

The addition of carbachol to superior cervical ganglia causes a rapid increase in tyrosine hydroxylation in situ. The increase occurs in ganglia from both newborn and adult animals, and in ganglia from animals pretreated with reserpine. The increase is not due to increased transport of the substrate. The increase is dependent upon the presence of calcium, and is additive to the stimulation produced by dibutyryl cyclic AMP. The stimulation seems specific for tyrosine hydroxylation; dopamine beta-hydroxylation is not increased. Preincubation experiments suggest that the carbachol-induced stimulation is due to a change in the availability of, or the affinity of the enzyme for, reduced pterin cofactor. The stimulation is inhibited by atropine and also by low concentrations of phenoxybenzamine or haloperidol, which suggests that it is caused by an action of carbachol on the interneurons in the ganglia.

Aging↗