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S Ando

Publications and source records attributed to S Ando.

At least 361 records · Page 20Linked to original sources
PubMed1987

Excess zinc ions are a competitive inhibitor for carboxypeptidase A.

The mechanism for inhibition of enzyme activity by excess zinc ions has been studied by kinetic and equilibrium dialysis methods at pH 8.2, I = 0.5 M. With carboxypeptidase A (bovine pancreas), peptide (carbobenzoxyglycyl-L-phenylalanine and hippuryl-L-phenylalanine) and ester (hippuryl-L-phenyl lactate) substrates were inhibited competitively by excess zinc ions. The Ki values for excess zinc ions with carboxypeptidase A at pH 8.2 are all similar [Ki = (5.2-2.6) X 10(-5) M]. The apparent constant for dissociation of excess zinc ions from carboxypeptidase A was also obtained by equilibrium dialysis at pH 8.2 and was 2.4 X 10(-5) M, very close to the Ki values above. With arsanilazotyrosine-248 carboxypeptidase A ([(Azo-CPD)Zn]), hippuryl-L-phenylalanine, carbobenzoxyglycyl-L-phenylalanine, and hippuryl-L-phenyl lactate were also inhibited with a competitive pattern by excess zinc ions, and the Ki values were (3.0-3.5) X 10(-5) M. The apparent constant for dissociation of excess zinc ions from arsanilazotyrosine-248 carboxypeptidase A, which was obtained from absorption changes at 510 nm, was 3.2 X 10(-5) M and is similar to the Ki values for [(Azo-CPD)Zn]. The apparent dissociation and inhibition constants, which were obtained by inhibition of enzyme activity and spectrophotometric and equilibrium dialysis methods with native carboxypeptidase A and arsanilazotyrosine-248 carboxypeptidase A, were almost the same. This agreement between the apparent dissociation and inhibition constants indicates that the zinc binding to the enzymes directly relates to the inhibition of enzyme activity by excess zinc ions. Excess zinc ions were competitive inhibitors for both peptide and ester substrates.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Sequence redesign and the assembly mechanism of the oxytocin/bovine neurophysin I biosynthetic precursor.

The structural organization of neurohypophysial hormone biosynthetic precursors and the interdependence between intramolecular folding and precursor self-association were examined using sequence-engineered mutants of the semisynthetic oxytocin/bovine neurophysin precursor (pros-OT/BNPI). In [N alpha 1-Ac,N epsilon 30,71-diacetimidyl, Ala2,des-His106] Pro-Ot/BNPI or [N alpha 1-Ac,Ala2]pros-OT/BNPI), two structural elements (Tyr2 and free alpha-amino group) were eliminated which were predicted to be critical for intramolecular conformation by stabilizing contact between hormone and neurophysin domains. This mutant was used to test the dependence of precursor self-association on intramolecular conformation. In the second mutant precursor, [N alpha 30,71-diacetimidyl,D-Pro7,D-Leu8,des-His106]p ro-OT/BNPI (or [D-Pro7,D-Leu8]pros-OT/BNPI), the stereochemistry at L-Pro7-L-Leu8 was changed to test the extent to which precursor conformation depends on ordered structure in the processing/spacer sequence which connects the interacting hormone and neurophysin I domains. Intramolecular conformation was characterized for the precursor and mutants by analytical affinity chromatography on immobilized hormone analog Met-Tyr-Phe and by circular dichroism. Data obtained by both methods showed that, while pros-OT/BNPI is folded, with hormone domain occupying the hormone-binding site of the neurophysin domain, the alpha-acetyl-Ala2 mutant is not so organized intramolecularly. When pros-OT/BNPI and the alpha-acetyl-Ala2 mutant were eluted on immobilized BNPII to measure self-association propensity, the native-like precursor was found to bind with 12-15-fold higher affinity than the assembly mutant. Thus, while pros-OT/BNPI assumes a molecular structure containing a high-affinity self-association surface induced by intramolecular hormone domain-neurophysin domain interaction, [N alpha 1-Ac,Ala2]pros-OT/BNPI does not. The results with the alpha-acetyl-Ala2 mutant show that intramolecular domain-domain interaction is the obligatory "trigger" which induces the high-affinity precursor self-association that likely drives precursor to aggregated forms in the concentrated intragranular environment that exists in peptide hormone-synthesizing cells. In contrast, affinity chromatographic and circular dichroism properties of the D-Pro7,D-Leu8 mutant show that this intramolecular trigger is dependent, but only weakly, on the conformation of the peptide sequence between domains, as judged by native-like interaction properties below 40 degrees C but lowered stability to elevated temperature.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1987

New solvent system for high-performance thin-layer chromatography and high-performance liquid chromatography of gangliosides.

New solvent systems consisting of acetonitrile, isopropanol and aqueous 50 mM potassium chloride or 2.5 M ammonium hydroxide were developed for the separation of gangliosides by high-performance thin-layer chromatography. These solvent systems seem to be superior for the resolution of polysialogangliosides such as tetra-, penta- and hexasialo species, as compared to chloroform-methanol-aqueous salt systems. The order of mobility of gangliosides in the ammoniacal solvent system is GD3 greater than GD1a greater than GM1 greater than GT1b greater than GD1b as compared with GM1 greater than GD3, GD1a greater than GD1b greater than GT1b in the neutral septem. A combination of these two solvent systems provides excellent two-dimensional separations of complex ganglioside mixtures. The neutral solvent system, acetonitrile-isopropanol-aqueous 50 mM potassium chloride, can be used for the separation of underivatized gangliosides by high-performance liquid chromatography on an Aquasil SS silica gel column. Ganglioside elution can be monitored at 208 nm because of the good UV-transparency of the effluent.

Chromatography, High Pressure Liquid↗
PubMed1987

Role of the essential thiol group in the thiol-activated cytolysin from Clostridium perfringens.

A hemolysin, 0-toxin, produced by Clostridium perfringens has one cysteinyl residue in the free thiol form which is essential for its hemolytic activity. The cysteinyl residue was shown to be located at a position about 5 kDa from the C terminus of the molecule by the method of cysteine-specific chemical cleavage. Modification of the residue with a thiol-blocking agent, 5,5'-dithiobis(2-nitrobenzoic acid), reduced the binding affinity of the toxin to sheep erythrocytes to 1/100 that of intact toxin, resulting in a failure of binding at low cell concentrations (0.5%). Thus the failure of hemolysis at low cell concentrations is primarily ascribed to a decreased affinity of the toxin for erythrocytes. Effects of the modification on the lytic processes were examined using high cell concentrations where considerable amounts of modified toxin bound to the cells. The modified toxin hemolyzes erythrocytes once it binds to them; however, the efficiency of hemolysis is reduced by the modification. These, and additional results indicating that modification alters the sensitivity of toxin molecules to protease digestion, show that thiol-modification inactivates the toxin by affecting both binding and the subsequent lytic processes, probably through a conformational change introduced in the toxin molecules.

Animals↗
PubMed1987

[Role of TRH or metoclopramide loading test in the diagnosis of so-called occult or latent hyperprolactinemia].

Present study was performed to investigate whether TRH or metoclopramide (MCP) loading test was useful for the diagnosis of so-called occulted or latent hyperprolactinemia (transient increase of serum prolactin levels more than 30 ng/ml during night; OHP). The circadian profiles of serum prolactin levels were examined in 31 women (age: 23-32 years old) whose BBT charts showed biphasic patterns. Blood samplings had been done every two hours through an intravenous indwelling catheter without any disturbances. And seven cases of the OHP were selected. Five cases of the control were also selected at random. Then, LH-RH (100 micrograms) and TRH (500 micrograms) loading test and LH-RH and MCP (10 mg) loading test were performed to these cases in the mid-luteal phase of the same menstrual cycle at interval of two or three days, and serum FSH, LH and prolactin levels (at 0, 30, 60, 90, 120 min. after the loading test) were determined by radioimmunoassay. Serum prolactin levels in the OHP group showed significant higher levels than those of the control from 22 to 6 o'clock (p less than 0.05-0.005). By the administration of 500 micrograms of TRH, serum prolactin levels of the OHP group increased significantly compared to those of the control at all sampling points (p less than 0.05-0.005), and also by the administration of 10 mg of MCP, the same result was obtained (p less than 0.05-0.02). The maximum peak of serum prolactin levels appeared at 30 min. after TRH or MCP loading.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Delayed memory dysfunction by transient hypoxia, and its prevention with forskolin.

Rats exposed to 40 min hypoxia 3 h before a one-trial learning passive avoidance task showed impaired memory retention 24 h later. this model was used to assess the ability of forskolin to restore the delayed memory dysfunction. Significant amelioration of memory retention was observed when forskolin (500 micrograms/kg, i.p.) was injected just after hypoxia. Forskolin is suggested to enhance cerebral blood flow and to facilitate memory function through the action of increased cyclic adenosine monophosphate (cAMP).

Animals↗
PubMed1987

Characterization of sulfated glucuronic acid containing glycolipids reacting with IgM M-proteins in patients with neuropathy.

In some patients with neuropathy and plasma cell dyscrasia, the serum IgM M-proteins are known to bind to the myelin associated glycoprotein and to peripheral nerve glycolipids. We have isolated two acidic glycolipids which bind to the M-protein from human cauda equina by DEAE-Sephadex, Iatrobeads, and high performance liquid column chromatographies. The major acidic glycolipid migrated between GM1 and GD1a and the minor acidic glycolipid migrated between GD1a and GD1b. Their structures were elucidated by sugar analysis, enzymatic digestion, mild acid hydrolysis, permethylation, fast atom bombardment mass spectrometry, and NMR studies. Their core structure was confirmed to be paragloboside by high performance thin-layer chromatography-immunostaining using anti-paragloboside monoclonal antibody. Both acidic glycolipids lacked sialic acid but contained sulfated glucuronic acid as their acidic moiety. The sulfate group in the glucuronic acid was established by periodate oxidation and permethylation studies to be attached to the 3 position. The structures of the two acidic glycolipids are therefore consistent with the following: IV3GlcUA(3-sulfate)nLcOse4Cer and VI3GlcUA(3-sulfate)nLcOse6Cer. Additionally, the free carboxyl group on the glucuronic acid residue was shown to be necessary to bind the IgM M-proteins from neuropathy patients.

Antibodies, Monoclonal↗
PubMed1987

Anterior perineal anorectoplasty for intermediate and high imperforate anus.

Anterior perineal anorectoplasty is a new technique for the repair of high imperforate anus. This technique allows direct access and clear visualization of the puborectalis sling and rectal pouch; division of the fistula and mobilization of the rectum can be precisely performed under direct vision, thereby reducing injury to surrounding structures; the pull-through of the rectum is readily facilitated; it obviates the need to change the position of the patient during the procedure; and mobilization of the rectum required to pull the rectum through is minimal, hence the late complication of mucosal prolapse is avoided. Details of the operative procedure are described herein.

Anal Canal↗
PubMed1987

Metabolic pathways of carotenoids in chum salmon Oncorhynchus keta during spawning migration.

1. Based on the contents and individual composition of carotenoids in the muscle, serum and ovaries of chum salmon during spawning migration, the reductive metabolism of astaxanthin to zeaxanthin was presumed to take place in the muscle of both male and female. 2. The metabolic rates of zeaxanthin and 4-keto-zeaxanthin in female serum were much faster than those in male serum.

Animals↗
PubMed1987

Isolation and characterization of a novel 2-aminoethylphosphonyl-glycosphingolipid from the sea hare, Aplysia kurodai.

A novel phosphonoglycosphingolipid named SGL-I' containing 1 mol of 2-aminoethylphosphonate residue was isolated from the skin of Aplysia kurodai using two silicic acid chromatography systems. Data obtained on methanolysis, permethylation, mild acid hydrolysis, and hydrogen fluoride treatment combined with thin-layer chromatography, gas liquid chromatography, gas chromatography-mass spectrometry, and proton magnetic resonance spectrometry showed that this glycolipid was 3-O-MeGal beta 1----3GalNAc alpha 1----3[6'-O-(2-aminoethylphosphonyl)Gal alpha 1----2]Gal beta 1----4Glc beta 1----1Ceramide. Palmitic acid, octadeca-4-sphingenine and anteiso-nonadeca-4-sphingenine are its major aliphatic components. The new glycolipid has essentially the same structure as another major phosphonoglycosphingolipid in the skin of Aplysia, SGL-II, that contains 2 mol of 2-aminoethylphosphonate residue, suggesting a metabolic relationship between the two.

Animals↗
PubMed1987

A T-shaped musculomucosal buccal flap method for cleft palate surgery.

The primary aim of cleft palate surgery is not only to close the cleft palate but to push back the palate by repositioning the levator muscle to ensure that normal speech is obtained. Although the pushback operation using a mucoperiosteal flap is a readily effective method for velopharyngeal closure, postoperative fistula sometimes occurs, especially when the cleft palate is wide. Furthermore, postoperative maxillary deformity, possibly due to elevating the mucoperiosteal palatal flap, is extremely troublesome. For the purpose of pushing back the nasal mucosa, we applied the Kaplan buccal flap method, which is also applicable for reestablishing the levator muscle sling. The other buccal flap is covered on the hinged flap of the pared cleft margins. This results in far less disturbance of maxillary growth. We call it the T-shaped buccal flap method, and we have applied it in over 30 patients with various cleft palates and have obtained satisfactory results.

Cheek↗
PubMed1987

Establishment and characteristics of five analbuminemic inbred strains of rats.

Five analbuminemic inbred strains of rats (AD/1, AD/2, AD/3, AD/4, AD/5) were established from Nagase analbuminemic rats (NAR). They showed no genetic differences in coat color, biochemical marker gene loci and skin grafting test. Their serum levels of total cholesterol, phospholipids, triglycerides, and beta-lipoproteins were compared with normal inbred strains (L) derived from Sprague-Dawley rats. Their plasma apoproteins were also examined. All inbred strains of analbuminemic rats showed hyperlipidemia progressing with age although there were slight variations in their lipid and apoprotein levels. These analbuminemic inbred strains of rats may be multigenic models of lipid metabolism abnormality.

Animals↗
PubMed1987

Synergism between human tumor necrosis factor and human interferon-alpha: effects on cells in culture.

The cytostatic and cytotoxic effects of highly purified natural human tumor necrosis factor (HuTNF-alpha) and natural human interferon-alpha (HuIFN-alpha) on 23 cell lines were studied in vitro. Natural HuTNF-alpha showed cytostatic and cytotoxic effects on PC-9, KHG-2, HT-1197, KG-1 and L-929 cells, and HuIFN-alpha showed both effects on KHG-2 and Daudi cells. A mixture of HuTNF-alpha and HuIFN-alpha (1:1, by unit) showed cytostatic and cytotoxic effects on HuTNF-alpha- or HuIFN-alpha-resistant cell lines such as KB, KATO-III, HEp-2, P-4788, as well as on HuTNF-alpha- or HuIFN-alpha-susceptible cells. Thus, the combined preparation of HuTNF-alpha and HuIFN-alpha expanded the spectrum of sensitive cells. The dosage of the mixed preparation required to produce 50% inhibition of cell growth was less than 20% of that of HuTNF-alpha or HuIFN-alpha alone. These results indicate that the cytostatic and cytotoxic effects of HuTNF-alpha and HuIFN-alpha are synergistically enhanced when they are administered together.

Cell Division↗
PubMed1987

In vitro and in vivo evaluations of BMY-28100, a new oral cephalosporin.

A new semisynthetic oral cephalosporin, BMY-28100, was evaluated for in vitro and in vivo antibacterial activities in comparison with cefaclor and cephalexin. BMY-28100 showed in vitro activity 3- and 10-fold more potent than that of cefaclor against Staphylococcus aureus and Streptococcus pneumoniae, respectively. BMY-28100 was slightly better than cefaclor and about 4 times more active than cephalexin against Haemophilus influenzae and Neisseria gonorrhoeae. Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis were comparably susceptible to BMY-28100 and cefaclor. The bactericidal activity of BMY-28100 against S. aureus, E. coli and P. mirabilis was equal to or twice as high as MIC value, which was similar to that of cefaclor. The stability of BMY-28100 against penicillinases was nearly comparable to that of cefaclor, whereas cefaclor was somewhat unstable to cephalosporinases. BMY-28100 was about twice as active as cefaclor against three Gram-positive bacterial infections. BMY-28100 was also more potent against infections of H. influenzae and P. mirabilis, but slightly less active against E. coli Juhl than cefaclor. Blood level parameters of BMY-28100 were significantly superior to those of cefaclor and slightly better than cephalexin in mice and rats. The urinary recovery of BMY-28100 was somewhat higher and comparable to that of cefaclor and cephalexin, respectively. BMY-28100 was more stable than cefaclor in human and calf sera at 37 degrees C.

Animals↗