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Biomedical subjects

K Ohno

Publications and source records attributed to K Ohno.

At least 775 records · Page 43Linked to original sources
PubMed1977

Polyamine metabolism I: Synthesis of dansyl derivatives of N-(monoaminoalkyl)- and N-(polyaminoalkyl)acetamides and elucidation in urine of a cancer patient.

The dansyl derivatives of N-(monoaminoalkyl)- and N-(polyaminoalkyl)acetamides were synthesized and unequivocally characterized. TLC of the dansyl derivatives obtained from human urine indicated the presence of N-[3-[(4-aminobutyl)amino]propyl]acetamide (N1-acetylspermidine, N-[4-[(3-aminopropyl)amino]butyl]acetamide (N8-acetylspermidine), and N-(4-aminobutyl)acetamide (N-acetylputrescine) in appreciable amounts. The dansyl derivatives of N1-acetylspermidine, N8-acetylspermidine, and N-acetylputrescine were isolated and purified using various chromatographic methods. The mass spectra of these compounds were similar to those of authentic samples, which confirmed the identity of these compounds and established the presence of N8-acetylspermidine as well as N1-acetylspermidine and N-acetylputrescine in human urine.

Carcinoma, Hepatocellular↗
PubMed1977

Polyamine metabolism II: N-(Monoaminoalkyl)- and N-(polyaminoalkyl)acetamides in human urine.

TLC and high-pressure liquid chromatographic examination of the dansyl derivatives obtained from human urine indicated the presence of N-[3-[4-aminobutyl)amino]propyl]acetamide (N1-acetylspermidine), N-[4-](3-aminopropyl)amino]buryl]acetamide (N8-acetylspermidine), N-(4-aminobutyl)acetamide (N-acetylputrescine), and N-(5-aminopentyl)acetamide (N-acetylcadaverine). The ratio of N1- to N8-acetylspermidine ranged from 10.3 in the urine of a patient with hepatoma to 1.1 in the urine of a normal subject. The three cancer patients had a considerably higher ratio of N1- to N8-acetylspermidine than did the three normal subjects. These findings indicate the ratio of N1- to N8-acetylspermidine in the 24-hr urine may serve as a biochemical marker for cancer.

Acetamides↗
PubMed1977

Light-induced formation of the 410 nm intermediate from reconstituted bacteriorhodopsin.

Light-induced formation of the 410 nm intermediate was investigated with reconstituted bacteriorhodopsin. Only bacteriorhodopsin with all-trans retinal formed the 410 nm intermediate in response to light excitation. In equilibrium in the dark, both native and reconstituted bacteriorhodopsin contained about equal amounts of the all-trans and 13-cis forms over a wide range of temperature.

Bacteriorhodopsins↗
PubMed1977

Formations of electrochemical proton gradient and adenosine triphosphate in proteoliposomes containing purified adenosine triphosphatase and bacteriorhodopsin.

Proteoliposome vesicles containing both bacteriorhodopsin of Halobacterium halobium and H+-translocating ATPase [EC 3.6,1.3] of a thermophilic bacterium, PS3, (TF0-F1) were reconstituted by either the dialysis method or the sonication method. Generation of the electrochemical proton gradient (deltamuH+) in these vesicles was measured using 9-aminoacridine for estimation of the chemical (deltapH) component and 8-anilinonaphthalene sulfonate for the electrical (deltaphi) component). In illuminated bacteriorhodopsin-vesicles the deltamuH+ reached 180-190 mV when reconstituted by the dialysis method and 210-220 mV when reconstituted by the sonication method. Vesicles reconstituted from both TF0-F1 and bacteriorhodopsin by the dialysis method generated a deltapH+ of about 200 mV on addition of ATP, while vesicles prepared by the sonication method generated very little deltamuH+, if any. These vesicles generated similar deltamuH+ on illumination to that found in bacteriorhodopsin-vesicles. Using vesicles reconstituted from both TF0-F1 and bacteriorhodopsin by the dialysis method, light dependent ATP synthesis was measured in relation to deltamuH+ formation. It was necessary to generate a deltamuH+ of above 170 mV for demonstration of appreciable formation of ATP and the greater the deltamuH+, the faster the rate of ATP synthesis.

Adenosine Triphosphatases↗
PubMed1977

Comparisons of body fluid volumes, plasma renin activity, hemodynamics and pressor responsiveness between juvenile and aged patients with essential hypertension.

Body fluid volumes, cardiac output, PRA and pressor responses to angiotensin II (AT) and norepinephrine (NE) were compared between untreated patients with essential hypertension aged younger than 35 (EH-I) and those aged older than 36 years (EH-II). Men blood volume, total body water and extracellular volume were not significantly different between the patients with essential hypertension and normotensive subjects. There were no difinite differences in each volume between the EH-I and EH-II patients either. However, the distribution of blood volume was significantly larger in the essential hypertensive patients than in the normotensive subjects, suggesting that the changes in blood volume might not be homogenous in essential hypertension. In addition, blood volume was noted to have a significant inverse correlation with PRA. Cardiac output at rest was slightly but not significantly less in the EH-I and EH-II groups than in the normotensive group. A decline in blood pressure following 'bed-rest' was accompanied by a decrease in total peripheral resistance index (TPRI). Thus, elevated peripheral vascular resistance seems to be responsible for the mild to moderate hypertension even in the younger patients. PRA and its increases in response to standing or furosemide were normal in the EH-I patients, while they were markedly suppressed in the EH-II patients as compared to the age-matched normotensive subjects. In addition, PRA had a significant inverse correlation with the blood pressure and the scores of the severity of hypertension in the patients with essential hypertension. Thus, it seems likely that low renin in essential hypertension is secondary to long-lasting hypertension. Pressor response to AT significantly correlated with mean blood pressure and that to NE did so with 24 hours' urinary sodium excretion in essential hypertensive patients. The influence of aging on the pressor responses were obscure: the relationships of the pressore responses to blood pressure or to urinary sodium excretion were not different between the EH-I and EH-II groups. The examinations were repeated in 16 patients with essential hypertension (16 to 48 year-old) in 11 to 30 days after the initial study. Twelve of the 16 patients had declines in blood pressure and TPRI at the second study. In 7 of the patients whose blood pressure declined following 'bed-rest', there were significant decreases in pressor response to AT and in blood volume and a significant increase in PRA (group A). The other 5 patients showed a significant decrease in PRA and an enhanced pressor response to NE (group B). The blood volume in the group A was significantly larger than that in the group B at the initial study. It is suggested that the cause of essential hypertension is not homogeneous in that the increased vascular resistance may have been attributed to sodium excess in some patients and to an increased sympathetic activity in others. Some additional factors remain to be taken into account to clarify the complicated aspects of essential hypertension.

Adolescent↗
PubMed1977

Proton translocation by ATPase and bacteriorhodopsin.

Stable membrane proteins and lipids are convenient to study biomembranes. Two stable proton translocating proteins were purified and reconstituted into vesicles capable of proton translocation. One was a thermostable ATPase (TF0-F1) of thermophilic bacterium PS3 and the other was rhodopsin of Halobacterium halobium. TF0-F1 was composed of a proton pump moiety (TF1) and a proton channel moiety (TF0). TF1 was the first membrane ATPase which was crystallized and reconstituted from its five polypeptides. Like TF0 and TF1, the rhodopsin in purple membrane was highly stable against dissociating agents, acids and alkali. Phospholipids of these biomembranes were also stable and contained no unsaturated fatty acyl groups. The molecular species of the phospholipids of PS3 were determined by mass chromatography. Measurements were made of the difference in electrochemical potential of protons (deltamicronH+) across the membrane of the reconstituted vesicles. The deltamicronH+ attained was 312 mV in TF0-F1 vesciles and was 230 mV in the rhodopsin vesicles. To conclude that electron transport components are not necessary for ATP synthesis in energy yielding biomembranes, two experiments were performed: The ATP synthesis was observed i) on acid-base treatment of TF0-F1 vesicles, and ii) on illumination of the rhodopsin-TF0-F1 vesicles.

Adenosine Triphosphatases↗
PubMed1976

Determination of diamines and polyamines in tissues by high-pressure liquid chromatography.

The 5-dimethylaminonaphthalene-1-sulfonyl (dansyl) derivatives of 1,2-diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane (putrescine), spermidine and spermine have been separated by high-pressure liquid chromatography on a Micropak CN-10 column using a programmed solvent gradient elution. The column eluate is monitored by a fluorescence detector. This method has been used to determine the levles of putrescine, spermidine and spermine in various tissues of rats and in L 1210 leukemic cells of mice grown in culture. The technique is sufficiently sensitive to detect ca. 40pmoles of putrescine and ca. 20 pmoles of spermidine and spermine, is quite specific and can be performed rapidly.

Animals↗
PubMed1976

Solubilization and purification of rat liver microsomal 1,2-diacylglycerol: CDP-choline cholinephosphotransferase and 1,2-diacylglycerol: CDP-ethanolamine ethanolaminephosphotransferase.

1. The procedure, which involved 2-step sonication of microsomes at pH 7.4 and then at pH 8.5 in the presence of sodium deoxycholate and subsequent dialysis, resulted in 4-5-fold purification of choline-phosphotransferase and ethanolaminephosphotransferase with the yield of 40-50%. 2. Ethanolaminephosphotransferase was further purified 8.5-fold over microsomes by sucrose density gradient centrifugation of the partially purified preparation, while cholinephosphotransferase activity was considerably lost during this procedure. No separation of the two transferases from each other was achieved at this step. 3. Cholinephosphotransferase required Mg2+ as cofactor, and microsomal phospholipids for its maximal activity. On the other hand, Mn2+ was more effective than Mg2+ as cofactor for ethanol aminephosphotransferase, and this enzyme was inhibited by microsomal phospholipids. 4. Both transferases were stimulated several-fold by sodium deoxycholate and also showed similar optimal pH ranging from pH 8.0 to 8.5. 5. Km values for 1,2-diacylglycerol emulsion were 81.0 muM for cholinephosphotransferase and 63.0 muM for ethanolaminephosphotransferase, respectively. CDP-choline and CDP-ethanolamine competitively inhibited, with the same Ki value (both 350 muM), ethanolaminephosphotransferase and cholinephosphotransferase, respectively. The Ki values obtained were much greater than the corresponding Km values for the cytidine substrates (36.4 muM for CDP-choline and 22.0 muM for CDP-ethanolamine). 6. The partially purified enzymes were further treated with Triton X-100. When enzyme activities were assayed with Mg2+, cholinephosphotransferase, although considerably inactivated, was partially separated from ethanolaminephosphotransferase by sucrose density gradient centrifugation of Triton-treated preparations. Furthermore, cholinephosphotransferase (but not ethanol-aminephosphotransferase) itself was partially separated into Mg2+ -requiring and Mn2+ -requiring components. In contrast, ethanolaminephosphotransferase assayed with either Mg2+ or Mn2+ formed a single peak together with Mn2+ -requiring cholinephosphotransferase.

Animals↗
PubMed1976

Further study on the turnover calculation of lung lecithins.

Using the data reported previously by Moriya and Kanoh, the metabolic turnover of rat lung lecithins was calculated on the basis of the new assumption that the formation rate (Va) of lecithins from diacylglycerols did not equal the disappearance rate (Vb) of lecithins because of the presence of precursors other than diacylglycerols. The ratio of Va/Vb was almost the same in dienoic lecithin as that for total lecithins, whereas a very low ratio was found in saturated and hexaenoic species. The turnover time of lung lecithins estimated was markedly shorter than those determined in much later experimental periods after administration of labeled precursors. The reason for this discrepancy was discussed.

Animals↗