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Biomedical subjects

T Kido

Publications and source records attributed to T Kido.

At least 217 records · Page 12Linked to original sources
PubMed1982

Successful Rastelli operation in infant with complete transposition of great arteries, levoposition of aorta, and subaortic ventricular septal defect.

A 10-month-old infant with complete transposition of the great arteries (TGA) [S,D,L] and large ventricular septal defect (VSD) without left ventricular outflow tract obstruction underwent successful Rastelli operation utilizing a 16 mm Hancock graft. The VSD was subaortic, and an internal conduit was placed easily. Postoperative hemodynamic conditions were satisfactory, and the patient was doing well eighteen months after operation. The feasibility of primary Rastelli operation for TGA and VSD in young infants is described.

Aorta↗
PubMed1982

Stimulation by calcium and other cations of the cholesterol binding to steroid-free cytochrome P-450scc purified from bovine adrenocortical mitochondria: the implication of ACTH-mediated calcium homeostasis on the cholesterol availability.

By utilizing purified cytochrome P-450scc from bovine adrenocortical mitochondria and cholesterol-containing dioleoylglycerophosphocholine liposomes, we have demonstrated a dramatic stimulation (2-3 fold) of cholesterol binding to the steroid-free cytochrome by Ca++. We theorize that ACTH modulates the increase of intracellular Ca++ concentration resulting in the increase of the cholesterol availability to the mitochondrial cytochrome.

Adrenal Cortex↗
PubMed1981

The transfer of cholesterol and hydroxycholesterol derivatives from liposome to soluble cytochrome P-450 scc.

We have studied the cholesterol-binding reaction with purified steroid-free cytochrome P-450scc. By mixing an aqueous solution of cholesterol-, pregnenolone- and progesterone-free cytochrome with cholesterol-containing liposomes, the low to high spin conversion of the hemoprotein was observed spectrophotometrically and by electron spin resonance spectroscopy. When the binding rates were compared at a fixed molar heme: cholesterol ratio of 1 : 1, 20 mol% cholesterol-dioleoylglycerophosphocholine liposomes react with the cytochrome at a faster rate than 50 mol% cholesterol-dimyristoylglycerophosphocholine liposomes, indicating that the availability of cholesterol molecules in an unsaturated membrane is better than in a saturated membrane. When the number of cholesterol-dioleoylglycerophosphocholine liposomes was increased, the cholesterol-binding rates increased markedly. These results imply that the collision of the liposomes with the soluble hemoprotein molecules plays an important role in the binding reaction under our experimental conditions. The binding reaction was found to be temperature-dependent with a refractive temperature at near 20 degrees C. From the comparison of the binding abilities among cholesterol derivatives tested, wer conclude that the alpha-face of the A-B transfused rings and the portion of the hydrocarbon side-chain of cholesterol are important for the binding. Additionally, polar derivatives had faster rates than non-polar steroids in structurally homologous series.

Adrenal Cortex↗
PubMed1981

Characterization of cytochrome P-450scc-containing liposomes.

Purified cytochrome P450scc from bovine adrenocortical mitochondria was incorporated into liposomes by the cholate-dilution method utilizing either dialysis or Sephadex gel filtration. Among synthetic phospholipids tested, dioleoylglycerophosphocholine showed the best stability during the incorporation of P450scc into liposomes. A maximum amount of heme was incorporated into liposomes at a molar ratio of phospholipid to the cytochrome of approx. 200. When P450scc was incorporated into the dioleoylglycerophosphocholine liposomes by the cholate-filtration method, the P450scc-containing liposomes showed two major populations on the elution pattern of the Sepharose 4B gel filtration, and were seen at a diameter of 200-600 A and its aggregated forms. When the cytochrome was incorporated into dioleoylglycerophosphocholine liposomes or cholesterol-free adrenocortical mitochondrial liposomes, P450scc was less stable than P450scc in aqueous solution. Cholesterol or adrenodoxin markedly stabilized the liposomal P450scc. Liposomal P450scc required cholesterol for its optimum reduction with adrenodoxin, adrenodoxin reductase, and NADPH in the presence of CO. About 70% of the total heme in the dioleoylglycerophosphocholine liposomes was reduced by the enzymatic reduction in the presence of cholesterol, indicating that 70% of the total molecules are exposed to the surface of the outer monolayer. In order to see the location of the heme in membrane, the dioleoylglycerophosphocholine-liposomal P450scc was subjected to p-chloromercuriphenyl sulfonic acid treatment. This reagent destroyed the liposomal P450scc. These results suggest that the heme is located in the proximity of the p-chloromercuriphenyl sulfonic acid reacting sites which are exposed to the surface, or located on the vincinity of polar heads of the membrane.

Adrenal Cortex↗
PubMed1981

Stimulation of cholesterol binding to steroid-free cytochrome P-450scc by poly(L-lysine). The implication in functions of labile protein factor for adrenocortical steroidogenesis.

At the low concentration of 2 nM, poly(L-lysine) stimulated the binding of dioleoylglycerophosphocholine liposomal cholesterol to steroid-free cytochrome P-450scc, which was purified from bovine adrenocortical mitochondria. Ca2+ and K+ ions displayed similar effects at much higher concentrations. These stimulatory effects were more significant at lower temperatures. Regardless of the presence of these activators, the maximal binding of cholesterol was observed between 20 and 30 mol % in dioleoylglycerophosphocholine liposomes. The examination of phospholipid fatty acyl groups on the cholesterol binding revealed that the initial binding rates decreased in the following order: (18c:2) greater than (18c:1) greater than (18c:3) greater than 18t:1) greater than (18c:1, 18:0) in the presence and absence of the lysine polypeptide. When 7 alpha-, 7 beta-, and 25-hydroxycholesterol were used as ligands, the stimulatory effect of the lysine polypeptide was not seen, indicating the specificity for cholesterol. When the cholesterol side chain cleavage activity was determined by the reconstituted system consisting of adrenodoxin reductase, adrenodoxin, and P-450scc, the stimulatory effects by poly(L-lysine) were observed. Polyglycine, poly(L-glutamic acid), putrescine, spermidine, spermine, and L-lysine had no effect, while poly(D-lysine) and poly(L-arginine) had activities much less than the lysine polypeptide.

Adrenal Cortex↗
PubMed1981

[Studies on the biological effects of low level lead exposures. Part 1. Estimation of usefulness of some biochemical tests as parameters for occupational lead exposures (author's transl)].

Male painters of ceramic works were examined for parameters of biochemical lead poisoning such as erythrocyte ALAD, free erythrocyte protoporphyrin (FEP), and coproporphyrin (CP) in urine as well as parameters of lead absorption such as lead concentration in blood and urine (PbB & PbU) in order to estimate the usefulness of those biochemical tests for occupational lead exposures. Under the lead exposure level of these painters (PbB 5-50 microgram/l), log ALAD and log FEP showed good linear correlations with PbB, while ALAU and CPU showed significant but lesser correlations with it. The log ALAD showed a good linear correlation with log PbU, log FEP, and ALAU fairly good ones, CPU a significant but lesser correlation with it. ALAD and FEP were equally the most sensitive tests for increasing PbB or PbU. ALAU was the next most sensitive test and CPU was the least sensitive. From the view point of sensitiveness and obvious meaning as a test for lead poisoning, FEP is the most desirable test for occupational lead exposures.

Adolescent↗
PubMed1981

[Studies on the biological effects of low level lead exposures. Part 2. Biochemical responses and subjective symptoms in female lead workers (author's transl)].

Females painters of ceramic works were examined for parameters of biochemical lead poisoning such as erythrocyte ALAD, free erythrocyte protoporphyrin (FEP), ALA and coproporphyrin (CP) in the urine as well as parameters of lead absorption such as lead concentration in the blood and urine (PbB and PbU). Results were compared with those of male painters. At the same time, subjective symptoms were questioned in both male and female painters. Under the lead exposure levels of these painters (PbB 5-50 microgram/dl, PbU 10-200 microgram/l), FEP alone, among the four biochemical tests for lead poisoning, showed a different behaviour between the male and female painters. Among female painters, significant higher incidence of the symptom of "tiredness" was recognized when the PbB level became more than 20 microgram/dl and significant higher incidence of the "history of abortion" was seen as the PbU level became more than 60 microgram/l. However, any relationship between subjective symptoms and PbB or PbU level was not recognized among male painters. These results suggest that female painters are more susceptible to lead exposure than male painters.

Adult↗
PubMed1979

The formation of binary and ternary complexes of cytochrome P-450scc with adrenodoxin and adrenodoxin reductase.adrenodoxin complex. The implication in ACTH function.

Binary and ternary complexes of bovine adrenocortical mitochondrial cytochrome P-450scc with adrenodoxin and adrenodoxin reductase.adrenodoxin complex are formed in the presence of cholesterol and Emulgen 913. Both cholesterol and Emulgen 913 are required for the binding of cytochrome P-450scc with adrenodoxin. Since phospholipids are able to replace Emulgen 913 in this reaction, in vivo phospholipids of the mitochondrial inner membrane appear to play the function of the detergent. The dissociation constants of the cytochrome.adrenodoxin complex are 0.3 to 0.4 microM at 130 microM dimyristoylphosphatidylcholine and 0.9 microM at 120 microM Emulgen 913, whereas the dissociation constant for the ternary complex of cytochrome P-450scc with adrenodoxin reductase and adrenodoxin is 4.0 microM at 150 microM Emulgen 913. The stoichiometry of binary and ternary complexes reveals the 1:1 and 1:1:1 molar ratios, respectively, judging from chemical analyses after the fractionation of the complexes by gel filtration. Emulgen 913, Tween 20, ethylene glycol, myristoyllysophosphatidylcholine, dimyristoylphosphatidylcholine, and phosphatidylethanolamine show the enhanced activity of cholesterol side chain cleavage reaction with cytochrome P-450scc, adrenodoxin, adrenodoxin reductase, and NADPH. These results, in conjunction with earlier experiments, lead us to the proposal on the structure of the hydroxylase complex in the membrane and to the hypothesis on the regulation of the enzymatic activity by the availability of substrate cholesterol to the cytochrome. Hence, we propose a mobile P-450scc hypothesis for the response of the mitochondrion to adrenocorticotropic hormone stimuli.

Adrenal Cortex↗