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Biomedical subjects

R Sato

Publications and source records attributed to R Sato.

At least 289 records · Page 16Linked to original sources
PubMed1989

Fibroblast growth factor release by bovine endothelial cells and human astrocytoma cells in culture is density dependent.

Basic fibroblast growth factor (bFGF) is a potent endothelial cell mitogen whose actions are mediated by binding to specific cell surface receptors on a variety of cell types. However, the amino acid sequence of bFGF does not contain a classical signal peptide sequence and the extent to which cellular stores of this mitogen are released is still a matter of some controversy. In the present study we examined the release of immunoreactive bFGF into serum-free conditioned medium of bovine corneal endothelial cells (BCE) and a human astrocytoma cell line, U87-MG. Western blotting analysis of BCE conditioned medium using N-terminal specific anti-bFGF serum revealed a single immunoreactive band of 32 kilodaltons, which was reduced to 18 kilodaltons in the presence of 8 M urea. Using a sensitive two-site immunoradiometric assay we were able to quantify the release of immunoreactive bFGF into the culture medium by BCE cells and by the human astrocytoma cell line U87-MG. In each case the release of bFGF was cell density dependent, but under all conditions the level of bFGF released was significantly greater in the transformed astrocytoma line, ranging from 15- to 50-fold higher than in the BCE cultures under various conditions. At 30% confluence the concentration of immunoreactive bFGF in the medium was maintained at a constant level for up to 24 h. However, the level of immunoreactive bFGF declined rapidly in confluent cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

The hydrogenation of alpha-hydroxymethylene-ketone derivatives to alpha-hydroxymethyl-ketone derivatives with a cell-free system of Streptomyces cinereocrocatus.

2',3'-Dihydro-5'-formylgriseofulvin (3), oxymetholone (5), and 3 beta-acetoxy-16-acetoxymethylene-5-androsten-17-one (9) were used as the substrates of a cell-free system from Streptomyces cinereocrocatus NRRL 3443. The results indicated that S. cinereocrocatus contains enzymatic activities which reduce the above three alpha-hydroxymethylene-ketones to the corresponding alpha-hydroxymethyl-ketones.

Hydrogenation↗
PubMed1989

Changes in plasma level of alpha-atrial natriuretic polypeptide (alpha-ANP) and responsiveness of the aorta to exogenous alpha-ANP subsequent to myocardial infarction in rats.

The changes in plasma level of alpha-atrial natriuretic polypeptide (alpha-ANP) and the relaxing responses to exogenous alpha-ANP of strips of rat aorta pretreated with methoxamine were examined at one, four and eight weeks after myocardial infarction induced by left coronary ligation. Responses to a beta-adrenergic stimulant, isoprenaline, and sodium nitroprusside of the vessel pretreated with high potassium were also evaluated up to twelve weeks. Plasma concentrations of immunoreactive alpha-ANP, which were measured at one, four and twelve weeks, were significantly elevated in rats with myocardial infarction (MI-rats) as compared with sham-operated rats (sham-rats). The relaxation responses of the aorta to exogenenous alpha-ANP in MI-rats were significantly reduced at one and four weeks as compared with sham-rats. The difference was, however, less obvious at eight weeks. The responses to isoprenaline tended to be reduced from the 1st week to the 12th week, and the difference was significant at eight weeks, whereas those to methoxamine and sodium nitroprusside were unchanged. It is concluded that the MI-rats are partially resistant to the vasodilating effects of alpha-ANP and isoprenaline without any change in responses to the alpha-stimulant and sodium nitroprusside, although these changes are transient.

Animals↗
PubMed1989

Monoclonal antibody EMR1a/212D recognizing site of deposition of extracellular lipid in atherosclerosis: purification and characterization of the antigen.

The monoclonal antibody EMR1a/212D, which recognizes the extracellular matrix in which lipids are deposited in atherosclerotic lesions, was developed previously. The macromolecule containing the epitope recognized by this antibody was purified from serum of WHHL rabbits, antigenic material similar to that found in serum and atherosclerotic plaques. The antigenic material was not associated with lipoproteins in serum. The antigenic material was purified in a single band by SDS-PAGE followed by DEAE-Sepharose CL-6B column chromatography (Pharmacia, Uppsala, Sweden), EMR1a/212D coupled immunoaffinity column chromatography, and HPLC equipped with a TSK gel G3000SWXL (Toso, Japan) column. The purified antigenic material was a glycoprotein of molecular weight 66 kd. It was remarkably high in glutamic acid and aspartic acid but low in arginine and lysine. It had an isoelectric point of pH from 5.4 to 5.9. It contained 22.2 mg of sugar per 100 mg protein, and sialic acid at least expressed the activity of the epitope because the antigenic activity was decreased by neuraminidase treatment.

Amino Acids↗
PubMed1988

Two species of human Fc epsilon receptor II (Fc epsilon RII/CD23): tissue-specific and IL-4-specific regulation of gene expression.

The Fc epsilon receptor II (Fc epsilon RII, CD23) functions in B cell growth and differentiation and in IgE-mediated immunity. The Fc epsilon RII structure expressed on various cell types has been analyzed identifying two species, Fc epsilon RIIa and Fc epsilon RIIb. Sequence analysis of the cloned cDNAs revealed that they differ only at the N-terminal cytoplasmic region, but share the same C-terminal extracellular region. These Fc epsilon RII species appear to be generated utilizing different transcriptional initiation sites and alternative RNA splicing. Fc epsilon RIIa is constitutively expressed only in normal B cells and B cell lines, whereas Fc epsilon RIIb expression is detectable in various cell types, such as monocytes and eosinophils. Normally, Fc epsilon RIIb is undetectable in B cells and monocytes, and can be induced by interleukin-4. Moreover, Fc epsilon RIIb is expressed on peripheral blood lymphocytes in atopic individuals. These findings may explain the difference in Fc epsilon RIIa and Fc epsilon RIIb function in B cells and the effector phase of IgE-mediated immunity.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1988

[A study of the secretion capacity of TSH-beta in patients with pituitary disorders].

We studied the secretion capacity of TSH-beta in 63 patients with various pituitary disorders, carrying out the observation of TSH-beta changes after TRH administration. Serum TSH-beta concentrations were measured by radioimmunoassay according to the modified method of Kourides. Serum TSH concentrations were measured by immunoradiometric assay, and serum concentrations of free thyroid hormones were measured by radioimmunoassay. Basal TSH-beta concentrations were below 0.39 ng/ml in 17 patients with Acromegaly, below 0.56 ng/ml in 5 patients with Prolactinoma, below 0.68 ng/ml in 4 patients with Cushing's disease, below 0.48 ng/ml in 12 patients with non-functioning tumor, below 6.4 ng/ml in 16 patients with SITSH, and below 0.45 ng/ml in 9 patients with other pituitary diseases. TSH-beta changes after TRH administration differed from TSH changes in 4 patients (25%) with Acromegaly, in 2 patients (67%) with Prolactinoma, in 5 patients (71%) with non-functioning tumor, in one patient (33%) with Cushing's disease, in 4 patients (100%) with Rathke's cleft cyst, in one patient with suprasellar meningioma, and in one patient with suprasellar arachnoid cyst. 2 patients (67%) with Prolactinoma, 3 patients (43%) with non-functioning tumor, all 6 patients with non-neoplastic SITSH, and one patient with Rathke's cleft cyst showed exaggerated TSH-beta changes after TRH administration. In patients with some pituitary disorders, we thought the secretion and synthesis of TSH and TSH-beta differed from that of normal subjects. We concluded that it was necessary to investigate the mechanism of secretion of TSH-beta in patients with pituitary disorders.

Acromegaly↗
PubMed1988

Comparative study of the block of Vmax by aprindine and quinidine in the guinea-pig heart muscle.

The depression of Vmax of the action potential in guinea-pig ventricular muscle by aprindine and quanidine was compared. Aprindine caused a more pronounced rate-dependent block (Kd = 10(-6) M at 3.3 Hz) than did quinidine (Kd = 1.6 X 10(-5) M at 3.3 Hz). Aprindine shifted the relationship between Vmax and resting potential to a more negative potential (mean 9.2 mV: 10 microM) than did quinidine (mean 5.7 mV: 10 microM). In addition, aprindine caused a more pronounced resting block (Kd = 1.3 X 10(-5) M) than quinidine (Kd = 8.6 X 10(-5) M). It is concluded that aprindine has a higher affinity for activated and/or inactivated and resting state channels than quinidine, making channels unavailable for conduction upon activation.

Action Potentials↗
PubMed1988

Microheterogeneity in the major phenobarbital-inducible forms of rabbit liver microsomal cytochrome P-450 as revealed by nucleotide sequencing of cloned cDNAs.

We have isolated one full-length cDNA clone, termed pHP1, and a number of clones of shorter insert lengths, tentatively called b14, b46, etc., all encoding phenobarbital- (PB-) inducible forms of rabbit liver microsomal cytochrome P-450, and determined their nucleotide sequences. The polypeptides encoded by these cDNAs can be classified into five types, represented by HP1, b14, b46, b52, and b54, the deduced amino acid sequences of which are more than 95% similar to one another. Amino acid differences among them total 24 positions, which are distributed over the entire sequence, in contrast to the microheterogeneity observed in two PB-inducible rat liver microsomal cytochromes P-450 (P-450b and P-450e). The primary structure deduced for the HP1 protein is 97% similar to that determined for rabbit P-450 LM2 (form 2), which has been purified by Coon and co-workers [van der Hoeven, T. A., Haugen, D. A., & Coon, M. J. (1974) Biochem. Biophys. Res. Commun. 60, 569-675; Haugen, D. A., & Coon, M. J. (1976) J. Biol. Chem. 251, 7929-7939] as the major PB-inducible form of rabbit liver microsomal cytochrome P-450. The amino acid sequence of P-450(1), which we have purified as the major PB-inducible rabbit liver cytochrome P-450, was partially determined with the sequence reported for P-450 LM2 as a reference. The two sequences are closely similar to each other, but at least two amino acid differences can be detected between them.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1988

Comparison of primary structures deduced from cDNA nucleotide sequences for various forms of liver microsomal cytochrome P-450 from phenobarbital-treated rabbits.

cDNA clones, termed pHP2, b32-3, b43, and b43-1, encoding cytochromes P-450 that are expressed in the liver of phenobarbital- (PB-) treated rabbits were isolated, and their nucleotide sequences were determined. pHP2 cDNA contains an open reading frame for a 490-residue protein and is a full-length counterpart of pP-450PBc2 [Leighton, J. K., Debrunner-Vossbrinck, B. A., & Kemper, B. (1984) Biochemistry 23, 204-210]. The b32-3 insert has a sequence for a protein whose primary structure is 91% similar to that of progesterone 21-hydroxylase P-450 1, though this cDNA lacks the sequence encoding the amino-terminal 110 residues. The overlapping clones b43 and b43-1 together encode an ethanol-inducible form of cytochrome P-450, though the amino-terminal five or more residues are missing in the composite b43/b43-1 sequence. Northern blot analysis showed that the b43/b43-1 protein is more strongly inducible by polycyclic aromatic hydrocarbons and isosafrole than by PB, in contrast to the case of the HP2 and b32-3 proteins. A comparison of the primary structures of eight forms of cytochrome P-450, including the HP2, b32-3, and b43/b43-1 proteins, that are expressed in the liver of PB-treated rabbits showed that 149 out of 487-492 amino acid residues are conserved in these cytochromes P-450. The eight forms can be assigned to three rabbit cytochrome P-450 gene subfamilies, P450IIB, P450IIC, and P450IIE. It was also shown that the members of the rabbit P450IIC subfamily can be further classified into three subgroups on the basis of their sequence similarity.

Amino Acid Sequence↗
PubMed1988

An interactive multivariate analysis of FCM data.

The procedure and results of the interactive multivariate analysis of FCM data are described. Using principal-components analysis, cluster analysis, and interactive maneuvers, this procedure facilitates an effective data compression from a four-dimensional space into two-dimensional space, then allows cluster separation. The procedure is especially effective for separating clusters, which are degenerated in the usual scattergrams. Programs were mostly written in C language on MS-DOS and were tested on four-dimensional analysis of the blood cells, which resulted in a successful separation of the degenerated clusters.

Cell Separation↗
PubMed1988

High pressure liquid chromatography methods for separation of omega- and (omega-1)-hydroxy fatty acids: their applications to microsomal fatty acid omega-oxidation.

Fatty acids (C12-C18) and their omega- and (omega-1)-hydroxy derivatives, when converted to p-bromophenacyl (PBP) esters, can be completely separated from one another by high pressure liquid chromatography (HPLC) on a silicic acid column using 0.5% (v/v) isopropanol in n-hexane. In this system, fatty acid PBP esters are eluted at the solvent front, whereas the retention times of the omega- and (omega-1)-hydroxy derivatives are 14-20 and 24-29 min, respectively. The PBP esters can also be separated by reverse phase HPLC on a muBondapak C18 column, a method which has been developed by Fan et al. (Fan, L. L., Masters, B. S. S., and Prough, R. A. (1976) Anal. Biochem. 71, 265-272) for separation of methyl esters of fatty acids and their omega- and (omega-1)-hydroxy derivatives. In the latter method, however, the retention times of omega- and (omega-1)-hydroxy derivatives are only about 2 min apart and an increase in the solvent polarity is needed for elution of the esters of unmodified fatty acids. Fatty acid PBP esters, however, can be obtained as independent peaks which are not disturbed by the solvent front. An application of the former method to measure fatty acid omega oxidation by liver microsomes and by a reconstituted monooxygenase system containing purified cytochrome P-450 is described.

Animals↗
PubMed1988

Both amino- and carboxy-terminal portions are required for insertion of yeast porin into the outer mitochondrial membrane.

Yeast porin, the major outer mitochondrial membrane protein, is synthesized without a cleavable extension peptide and post-translationally inserted into the membrane. When inserted into the membrane, it acquires resistance to externally added trypsin. To locate the sequences responsible for membrane insertion and topogenesis in the primary structure of yeast porin, we constructed several deletion and chimeric mutants of the porin cDNA. These cDNAs were expressed in vitro and the products were assayed for capacity to be correctly inserted into isolated mitochondria. It was thus found that deletion of the segment spanning residues 37-98 did not appreciably impair the insertion competence and the inserted protein became resistant to trypsin. On the other hand, the porin mutant lacking the segment consisting of residues 17-98 did not acquire the trypsin resistance, though it could bind to mitochondria specifically. Deletion of the carboxy-terminal 62 amino acid residues also abolished the capacity to be correctly inserted into mitochondria. We conclude that information required for membrane insertion and intramembranous topogenesis of the porin molecule is stored not only in the amino-terminal region but also in the carboxy-terminal portion.

Alkalies↗
PubMed1988

Purification and properties of a form of UDP-glucuronyltransferase from liver microsomes of 3-methylcholanthrene-treated rats.

A form of UDP-glucuronyltransferase has been purified from liver microsomes of 3-methylcholanthrene-treated rats by a simple and rapid method involving chromatography on DEAE-Toyopearl and UDP-hexanolamine Sepharose columns. The purified preparation gave a single protein band (Mr 54,000) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It catalyzed the glucuronidation of not only phenolic xenobiotics such as 4-nitrophenol, 1-naphthol, and eugenol but also serotonin, which is an endogenous compound. Its activities toward 4-hydroxybiphenyl and testosterone were very low and no activity was detected toward bilirubin. After removal of the detergent (Emulgen 911), the transferase activity was stimulated by various phospholipids, about 10-fold activation being attained with phosphatidylcholine and lysophosphatidylcholine. On nitrocellulose sheets concanavalin A, but not wheat germ agglutinin, bound to the purified transferase, and this binding was abolished in the presence of alpha-methylmannoside and after treatment of the enzyme with endo-beta-N-acetylglucosaminidase H (Endo H). These observations provided evidence that the transferase is a glycoprotein carrying a "high mannose type" of oligosaccharide chain(s). The NH2-terminal 7 residues of the purified enzyme were determined to be Thr-Lys-Leu-Leu-Val-Trp-Pro.

Animals↗
PubMed1988

Electrophysiologic diagnosis of cervical OPLL myelopathy using evoked spinal cord potentials.

The purpose of this study is to establish the correct diagnosis of the location and extent of intraspinal cord lesions in cases of continuous or mixed-type ossification of the posterior longitudinal ligament and to estimate the postoperative prognosis using evoked spinal cord potentials (ESCP). Twenty-six patients, who underwent surgery from 1985 to 1987 and who have been followed for more than 6 months, were examined using a conductive ESCP, which demonstrates lower extremity, bowel, and bladder function, and a segmental ESCP and dermatome segmental ESCP, which demonstrate upper extremity function. A five-pole recording electrode was placed in the cervical epidural space. The stimulation sites were the thoracic epidural space for conductive ESCP, the median nerve at the elbow for the segmental ESCP, and the finger surface for the dermatome segmental ESCP. In cases in which the ESCP disappeared at the middle of the narrow cervical spinal canal, another stimulating electrode was placed in the cisterna magna, and a descending conductive ESCP was recorded to monitor the upper border of the spinal lesion. New findings, which could not be observed by roentgenograms, myelography, and CT scan, were detectable using this technique.

Aged↗