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Biomedical subjects

R Sato

Publications and source records attributed to R Sato.

At least 397 records · Page 22Linked to original sources
PubMed1981

Binding of dihydrotestosterone, R 1881 and R 5020 in cytosols from normal, benign hypertrophic and cancerous human prostates.

The binding of dihydrotestosterone, R 1881 and R 5020 was examined in cytosols of normal, benign hypertrophic and cancerous tissues of the human prostates. Almost all samples obtained by open operation showed high affinity binding to these ligands. Dissociation constants of the binding to these ligands were approximately 10(-9) M irrespective of the pathological state of the prostates. Maximum binding sites for dihydrotestosterone seemed to be greater in normal tissues than in the pathological ones. However, maximum binding sites for R 1881 and R 5020 were not significantly different among the normal and pathological prostates examined in the present study. Moreover, some correlation was observed between the maximum binding sites for R 1881 and those for R 5020. The samples resected by TUR seemed to be inadequate for analyses of androgen binding.

Cytosol↗
PubMed1981

Progestin-binding protein in human benign prostatic hypertrophy.

Cytosols from human benign prostatic hypertrophy contained progestin-binding components which bound to R 5020, ORG 2058 and progesterone in high affinity fashion. Most of the protein bound to R 5020 was recovered in the precipitate with 0-30% saturation of ammonium sulfate. The R 5020-binding protein showed sedimentation coefficients of 3.6S and 8.4S, and was eluted in the void volume of a Sephadex G-200 column. This protein was clearly distinguished from the dihydrotestosterone-binding protein by its precipitability by ammonium sulfate, heat stability and susceptibility to delipidization. R 5020 and ORG 2058 binding were markedly inhibited by the addition of R 1881, therefore, most of the binding to progestin in cytosols from the benign prostatic hypertrophy seems to be also the sites for R 1881. Although nuclear extract by 0.4 M KCl showed R 1881 binding, the extract did not contain the R 5020-binding protein, and this suggested that the progestin-binding protein observed in the cytosols does not seem to be the steroid receptor.

Carrier Proteins↗
PubMed1981

Measurement of androgen receptor in cytosols from normal, benign hypertrophic and cancerous human prostates.

The binding of R 1881 in cytosols from the normal, benign hypertrophic and cancerous human prostates was examined in the presence of molybdate and triamcinolone acetonide. The addition of 10 mM Na2MoO4 resulted in an increase in the stability of the binder without any change in Kd. Triamcinolone acetonide added to the incubation of cytosol with R 1881 modified the inhibition pattern by other steroids, and the binding in the presence of triamcinolone acetonide exhibited the characteristics of androgen receptor. The complex of cytosol and R 1881 formed in the incubation in the presence of triamcinolone acetonide was sedimented at 8.5S. Kd of the binding to R 1881 of the normal and pathological prostates was almost identical, but maximum binding sites of the androgen receptor were larger in benign hypertrophic and cancerous prostates than in normal tissues. For the assay of binding capacity in needle biopsy specimens, one point determinations were performed using 2.5 nM R 1881 as the ligand. The number of binding sites obtained by this method were well correlated with those obtained by the Scatchard plot in various prostatic tissues.

Cytosol↗
PubMed1980

Effect of KC-9432, a new hypolipidemic compound, on high density lipoprotein cholesterol in rats.

KC-9432 (a new hypolipidemic compound, alpha-[p-(p-chlorobenzoyl) phenoxy-alpha-cyclohexyl acetic acid ethyl ester) was studied in rats for its effect on plasma lipid and lipoprotein levels. KC-9432 was particularly effective in hyperlipidemia in rats fed with a diet containing 2% cholesterol and 1% sodium cholate. The hypocholesterolemic activity of KC-9432 was far more potent than that of clofibrate. KC-9432 markedly increased the reduced HDL cholesterol level in dietary-induced hyperlipidemia in rats.

Animals↗
PubMed1980

Topological studies of the membrane-binding segment of cytochrome b5 embedded in phosphatidylcholine vesicles.

Carboxypeptidase Y (CPY) digestion of cytochrome b5 incorporated into single-walled liposomes of egg phosphatidylcholine (PC) resulted in the release of 25 amino acid residues form each molecule of the cytochrome and concomitant detachment of the cytochrome from the vesicles. This finding suggests that the COOH-terminus of the incorporated cytochrome is exposed to the outer surface of the liposomal membrane, since the cytochrome-carrying vesicles were shown to be impermeable to macromolecules such as dextran T-40 by isopycnic centrifugation studies. The possibility that CPY had attacked a small amount of free cytochrome b5 which was in equilibrium with the liposome-bound cytochrome could be excluded by the finding that transfer of the bound cytochrome to the unbound state was a much slower process than CPY-induced detachment of cytochrome b5. CPY could also attack the COOH-terminus of cytochrome b5 embedded in dipalmitoyl-PC liposomes even below the phase transition temperature of the synthetic phospholipid. Moreover, the tyrosine residue(s) near the COOH-terminus of the PC vesicle-bound cytochrome could be readily iodinated by the action of lactoperoxidase added externally. These observations indicate that the COOH-terminus of the liposome-bound cytochrome, like its heme-containing, hydrophilic domain, is exposed to the outer surface of the vesicular membrane. The cytochrome detached from the vesicles by CPY digestion could neither rebind to the liposomes nor form an oligomeric aggregate, suggesting that CPY had removed all the amino acid residues which are required for the protein to bind to membranes. The mechanism of CPY-induced detachment of cytochrome b5 from liposomes and the size of the peptide segment which is directly involved in the interaction of the cytochrome with the lipid bilayer membranes are discussed.

Amino Acid Sequence↗
PubMed1980

Multiple forms of cytochrome P-450 purified from liver microsomes of phenobarbital- and 3-methylcholanthrene-pretreated rabbits. I. Resolution, purificaton, and molecular properties.

A method is described for the separation and purification of different forms of cytochrome P-450 from liver microsomes of phenobarbital (PB)- and 3-methylcholanthrene (MC)-pretreated rabbits. It consists of solubilization of microsomes with cholate, followed by successive chromatography on omega-aminooctyl Sepharose 4B, hydroxylapatite and CM-Sephadex C-50 columns. Separation of different forms of cytochrome P-450 is achieved in the aminooctyl Sepharose and hydroxylapatite chromatograhy steps. This method permits the separation of three forms of cytochrome P-450, i.e. "P-450(1)," "P-450(2)," and "P-488(1)," from PB-induced microsomes; P-450(1), the main cytochrome P-450 component in these microsomes, and P-448(1) can each be obtained in a gel-electrophoretically homogeneous state, whereas P-450(2) can be obtained in a partially purified state. Application of the same method to MC-induced microsomes led to the purification of P-448(1), the main component in these microsomes, to homogeneity and to partial purification of a fourth form, i.e. "P-450(3)." P-448(1) from MC-induced microsomes seems to be identical with P-448(1) from PB-induced microsomes in monomeric molecular weight (54,000), amino acid composition and chromatographic behavior. However, P-448(1) from MC-induced microsomes, but not P-448(1) from PB-induced microsomes, contains 0.18 to 0.88 mol of tightly bound MC per mol of protein. P-450(1) has a molecular weight of 49,000 and its amino acid composition is clearly different from that of P-448(1). Although P-450(2) is similar in molecular weight, they differ from each other in chromatographic behavior. P-450(3) seems to be different from P-450(1) in molecular weight, though they are similar to each other in chromatographic behavior. All the cytochrome P-450 preparations can be freed from the detergents used in the purification procedure by CM-Sephadex C-50 chromatography. Detergent-free P-450(1), P-450(2), and P-448(1) exist in aqueous solution as oligomeric aggregates.

Amino Acids↗
PubMed1980

Multiple forms of cytochrome P-450 purified from liver microsomes of phenobarbital- and 3-methylcholanthrene-pretreated rabbits. II. Spectral properties.

The spectral properties of multiple forms of cytochrome P-450 purified or partially purified from liver microsomes of phenobarbital (PB)- and 3-methylcholanthrene (MC)-treated rabbits have been studied. Both optical absorption and EPR studies have shown that the oxidized forms of P-450(1), P-450(2) (from PB-treated animals), and P-450(3) (from MC-treated animals) are in the low spin state, having a Soret absorption peak at 417-418 nm. Oxidized P-448(1) (from both PB- and MC-treated animals), on the other hand, shows a Soret peak at 393 nm and a weak band at 646 nm. This and EPR evidence indicate that P-448(1) contains heme which is predominantly in the high spin state, though EPR studies at low temperature indicate the presence of a small amount of low spin ferric heme. The presence of tightly bound MC in P-448(1) purified from MM-treated animals is reflected by characteristic absorption peaks in the ultraviolet region, but this does not affect the absorption spectra in the Soret and visible regions. Emulgen 913, a nonionic detergent, causes the conversion of oxidized P-448(1) from the high to the low spin state, as evidenced by optical absorption and EPR results; bound MC inhibits this conversion in a noncompetitive way. Binding of ethyl isocyanide to reduced P-450(1) and P-448(1) results in the appearance of two Soret peaks in the 430 and 455 nm regions, the relative intensities of which are dependent on pH. At any pH the 455 nm peak of P-448(1) is always higher than that of P-450(1). Benzphetamine and aniline, added to oxidized P-450(1), cause Type I and Type II spectral changes, respectively, but the magnitudes of the changes are small in both cases. The Soret peak of oxidized P-448(1) at 393 nm is completely shifted to 420 nm on addition of aniline, resulting in a reverse Type I spectral change; acetanilide causes the conversion of the Soret peak to the low spin state to only a slight extent. The conversions caused by aniline and acetanilide are both inhibited by the presence of tightly bound MC. On the basis of these and other observations, the spin state of these P-450's are discussed.

Acetanilides↗
PubMed1980

A critical evaluation of povidone-iodine absorption in thermally injured patients.

Povidone-iodine ointment is a widely used topical antimicrobial agent in thermally injured patients. In 17 patients with burns ranging from 4 to 85% TBSA this agent was applied to both partial- and full-thickness burns. Peak serum iodine levels in patients treated within 24 hours of injury ranged from 595 to 4,900 micrograms per dL. The amount of iodine absorbed was directly related to the size of the burn. Serum iodine levels continued to rise until the drug was discontinued and remained elevated for as long as 7 days after discontinuance. Iodine excretion was directly related to renal function. The highest serum and lowest urinary iodine levels were present in patients who developed renal failure. Thyroid function was not affected by drug usage. A proven cause-and-effect relationship between the elevated serum iodine attributed to the absorption of povidone-iodine and metabolic acidosis, hypernatremia, and hyperosmolarity was not established. Close monitoring of the patient's fluid and electrolyte balance is imperative during drug usage. The drug is contraindicated in any patient with impaired renal function. The high serum levels of this inorganic ion imply potential toxicity, but clinical evidence of cell or organ toxicity is as yet undetermined.

Absorption↗
PubMed1980

Periarteritis nodosa in spontaneously hypertensive rats--immunohistological study and permeability test.

Spontaneously hypertensive rats develop periarteritis nodosa spontaneously with high incidence. Immunohistology of periarteritis nodosa reveals that fibrinogen constantly deposits in the wall of the diseased artery in exceptional combination with IgG but never with complement (C3). This fact suggests that periarteritis nodosa in spontaneously hypertensive rats may not be arteritis of immune complex type. Permeability test using mainly peroxidase as a tracer demonstrates that increased arterial permeability in spontaneously hypertensive rats is recognizable since 4 to 6 months of age without sexual difference in its intensity. In male spontaneously hypertensive rats periarteritis nodosa is observed in 6 of 11 and the arterial permeability increases more pronouncedly in the positive group, whereas 5 female spontaneously hypertensive rats of various ages are free from periarteritis nodosa irrespective of high arterial permeability. Therefore, high arterial permeability does not always lead to regular development of periarteritis nodosa especially in female spontaneously hypertensive rats.

Animals↗