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Biomedical subjects

K Adachi

Publications and source records attributed to K Adachi.

At least 595 records · Page 33Linked to original sources
PubMed1983

Enantioselective synthesis of new analogues of neplanocin A.

An efficient synthesis of analogues of (-)-aristeromycin (1) and (-)-neplanocin A (2) has been developed in an enantioselective and stereocontrolled manner by chemicoenzymatic strategy. The symmetric unsaturated dimethyl ester (3) was quantitatively hydrolyzed with pig liver esterase to yield a half ester (4). Decarboxylative ozonolysis followed by chemical transformation afforded versatile chiral intermediates, cyclopentylamine (7) and cyclopentenylamine (9), which were converted to carbocyclic analogues of 5-aminoimidazole-4-carboxamide riboside (16), (18), uridine (21), cytidine (23), and guanosine (25). The cytidine analogue (23) was found most active against KB cells in culture.

Adenosine↗
PubMed1983

Novel method for estimation of chlorinated pesticide residues in milk.

A new, simple, and rapid procedure for determining chlorinated pesticide residues in milk is described. The entire acetonitrile extract from milk is passed through a 0.5 g activated charcoal chromatographic column. Chlorinated pesticides adsorbed on the charcoal are eluted with 100 mL acetone-hexane (1 + 1). The eluate is washed with water and 1% sodium carbonate solution, and chlorinated pesticides are extracted with hexane. The extract is concentrated and measured by electron capture gas chromatography. Recoveries from 50 mL milk samples fortified with 0.04-1.6 micrograms of different BHC isomers, 0.05-2 micrograms DDT and its metabolites, and 0.05-0.5 micrograms dieldrin ranged from 86.9 to 103.2%.

Acetonitriles↗
PubMed1982

Polymerization of carbamylated deoxyhemoglobin S in concentrated phosphate buffer.

To study the effect of carbamylation on the polymerization of deoxyhemoglobin (HB) S, three types of NH2-terminal-carbamylated Hb S specifically modified at the NH2 termini at the alpha, beta, or all four subunit chains, alpha c2 beta sc2, and alpha 2 beta sc2, and epsilon-lysine-carbamylated Hb S were prepared by reacting Hb S with cyanate. The solubility of deoxy-Hb S in concentrated phosphate buffer was increased by carbamylation of the NH2-terminal residues of beta chains. Kinetic studies on the polymerization of purified carbamylated deoxy-Hb S showed that the length of the delay time prior to polymerization is related to solubility; carbamylated Hb S with higher solubilities exhibited longer delay times than those with lower solubilities. The delay times for alpha 2 beta sc2 and alpha c2 beta sc2 were prolonged 2-3- and 3-6-fold, respectively, as compared to those of native deoxy-Hb S in 1.8 M phosphate buffer. The logarithmic plot of reciprocal delay time versus hemoglobin concentration of alpha c2 beta s2, alpha 2 beta sc2, and epsilon-lysine-carbamylated deoxy-Hb S showed straight lines with slopes (n values) of 4.0, 3.8, 3.6, and 3.5, respectively. These values are slightly higher than the n value of native deoxy-Hb S (n = 2.7), suggesting that nuclei of carbamylated Hb S are larger than those of native deoxy-Hb S.

Buffers↗
PubMed1982

An improved purification and further characterization of the messenger ribonucleic acid for the fatty acid synthetase from rat liver.

High purity fatty acid synthetase mRNA has been prepared from rat liver. The translational purity of the mRNA preparation was at least 27% as judged by the percentage of the radioactivity incorporated into acid-insoluble material that was precipitated by anti-fatty acid synthetase antibody. The specific activity of the mRNA was 220-times greater than that reported previously from this laboratory [1]. The large increase in the specific activity was achieved by the repeated use of high resolution linear-log sucrose density gradient centrifugation and the removal of 28 S rRNA by Sepharose 4B chromatography, as well as by the optimization of the K+ concentration (160 mM) in the reticulocyte lysate translation system. The mRNA preparation showed a single major band on agarose gel electrophoresis under denaturing conditions, and the translational activity of the fatty acid synthetase mRNA on the gel was found to coincide with this band. The molecular weight of the fatty acid synthetase mRNA is 2.5.10(6) Da. The mRNA directed the synthesis of fatty acid synthetase with a molecular weight indistinguishable from that of the authentic enzyme subunit (Mr = 240 000). The copurification of the translation product and authentic enzyme revealed that the fatty acid synthetase polypeptides synthesized in the reticulocyte lysate system are assembled in vitro into dimers, the native form of the enzyme.

Animals↗
PubMed1982

Effect of liganded hemoglobin S and hemoglobin A on the aggregation of deoxy-hemoglobin S.

The effect of the carbonmonoxy forms of Hb S and Hb A on the solubility and kinetics of the aggregation of deoxy-Hb S in concentrated phosphate buffer was studied. The delay time was prolonged exponentially when the ratios of CO-Hb S and CO-Hb A to deoxy-Hb S were increased. This increase in the delay time prior to aggregation can be explained by the decrease in the concentration of deoxy-Hb S. As with deoxy-Hb A, the n value for the delay time prior to the aggregation of deoxy Hb S was unaffected by CO-Hb S and CO-Hb A. Electrophoretic and spectrophotometric analyses of the composition of CO- and deoxy-Hbs A and S in the solution before and after aggregation showed that CO-Hb S co-polymerized with deoxy-Hb S but that CO-Hb A did not. The amount of CO-Hb S in the polymer phase depended on the initial fraction of the CO form of Hb S. The participation of CO-Hb S in the polymer phase was further confirmed by direct measurement of the absorption spectra of the polymer phase after it was dissolved in deoxygenated phosphate buffer. From these results, we concluded that nuclei are formed only from deoxy-Hb S, but that once nuclei are formed, CO-Hb S and deoxy-Hb A co-polymerize with deoxy-Hb S.

Carbon Monoxide↗
PubMed1982

Prospection of chronic vasospasm by CT findings.

Haematoma of the basal cistern was classified into five grades. A little or moderate haematoma (1+ or 2+) disappeared from the basal cistern in 3 or 4 days, however much or severe haematoma (3+ or 4+) remained over a week. Vasospasm occurred in a high number of the cases in which the haematoma was recognized in the basal cistern later than 4 days after SAH not only in operative case but also in conservative case. However vasospasm occurred rarely in cases with early operation within 24 hours after onset except for cases with severe packed haematoma (4+) in the basal cistern.

Adult↗
PubMed1982

7 beta,12 beta-Dihydroxy-5 beta-cholan-24-oic acid as an internal standard for quantitative determination of bile acids by gas chromatography.

In order to find an artificial internal standard compound for quantitative determination of bile acids by gas chromatography, 7 alpha,12 alpha-, 7 alpha, 12 beta-, 7 beta, 12 alpha- and 7 beta,12 beta-dihydroxy-5 beta-cholan-24-oic acids were chemically synthesized with cholic acid (1) as the first starting material. The gas chromatographic retention time of 7 beta,12 beta-dihydroxy-5 beta-cholan-24-oic acid (beta beta-isomer) was more different from that of natural bile acids than the other isomers. Moreover, beta beta-isomer was extracted in the same fraction as the bile acids from urine, and no urinary substance had the same retention time as beta beta-isomer. No artifact was produced from beta beta-isomer during the analysis procedure. It was concluded that the beta beta-isomer is an internal standard compound with certain advantages for the quantitative determination of bile acids in urine by gas chromatography, irrespective of the recovery rate during the analysis procedure.

Bile Acids and Salts↗
PubMed1982

Measurement of adenosine 3',5'-monophosphate-dependent protein kinase and phosphorylase activities in in vivo conditions.

Microassay procedures for cAMP-dependent protein kinase and phosphorylase were developed which detected these activities in less than 25 micrograms of frozen-dried epidermis from a punch biopsy of skin without homogenization. Using these procedures, the activation of cAMP-dependent protein kinase and phosphorylase by beta-adrenergic stimulation in mouse skin was studied in vivo. Cyclic AMP-dependent protein kinase was stimulated by isoproterenol and inhibited by propranolol. Isoproterenol stimulation also activated phosphorylase a in mouse skin. In normal epidermis and uninvolved and involved epidermis from psoriatic patients no significant differences were found in the activities of cAMP-dependent kinase and phosphorylase a. In all experiments we observed that the unstimulated activity ratios of phosphorylase a/total phosphorylase were around 20-30%; these values were much lower than those hitherto reported and show a preponderance of phosphorylase b rather than a. We suggest that in previous reports where phosphorylase a domination was found, phosphorylase b to a activation occurred during homogenization. The data also suggest that in the steady state no obvious defect in basic activities of cAMP-dependent protein kinase and phosphorylase is observed in psoriatic skin.

Animals↗
PubMed1982

Epidermal surface receptors which link pharmacological mediators to the adenylate cyclase system.

The major purpose of our studies has been to investigate various stimulators of the epidermal adenylate cyclase system. We have recognized the occurrence of four distinct adenylate cyclase systems which respond respectively to catecholamine, histamine, prostaglandin and adenosine. The exposure of floating skin slices in vitro to a stimulator causes a rapid intracellular accumulation of cyclic AMP, which is always transient. Further addition of the same stimulator will not stimulate the same receptor system against the state of 'refractoriness'. The addition of any of the other stimulators can increase the cyclic AMP level. Furthermore, the fact that each stimulator can yield an 'additive' stimulatory effects leads to the conclusion that the epidermis has four distinctly specific and independent adenylate cyclase systems. Our recent investigations have been directed to the analyses of subunits of these skin surface receptor-adenylate cyclase systems. We used two experimental systems, i.e. one being a 'leaky' cell system in which its subunits such as receptor, GTP-regulatory protein and the catalytic unit (adenylate cyclase) are still linked together, and the other being independent preparations of the receptor and catalytic units (with GTP-regulatory protein). These systems allowed us to probe the cell membrane from the inside as well as from the outside. Some of the preliminary kinetic data are herein introduced.

Adenylyl Cyclases↗
PubMed1982

Biosynthetic ornithine and arginine decarboxylases: correlation of rates of synthesis with activities in Escherichia coli during exponential growth and following nutritional shift-up.

Whether guanosine tetraphosphate (ppGpp) has a role in the regulation of the putrescine biosynthetic enzyme, ornithine decarboxylase, in Escherichia coli is controversial. Different laboratories have reported either direct or indirect correlations between ppGpp levels and ornithine decarboxylase activity using different in vivo conditions. In this report, using conditions in vivo to modulate ppGpp levels, experiments are described which bear on the controversy. The rates of synthesis and biological activities of the biosynthetic ornithine and arginine decarboxylases (ODC and ADC) were measured in E. coli K-12 during experimental growth and during nutritional shift-up. There were good correlations between changes in their respective activities and the rates of synthesis of these enzymes during steady state or shift-up. ODC activity or rate of synthesis changed directly in concert with ppGpp levels, while ADC activity or rate of synthesis changed inversely with ppGpp levels. These observations support the contention that ppGpp does not inhibit ODC activity.

Carboxy-Lyases↗
PubMed1982

Effects of thyrotropin releasing hormone on cerebellar mutant mice--a kinesiological comparison between rolling mouse Nagoya, weaver and reeler.

Rolling Mouse Nagoya (RMN), weaver and reeler mice were examined for the clinical effectiveness of drugs (thyrotropin releasing hormone (TRH), reserpine, L-dopa) that are reported to facilitate or alter the metabolic system of noradrenaline (NA). Behavioral changes and ataxic gait were recorded by 16 mm cinefilms and EMG of the thigh extensor muscles. In addition, latencies in the reflex discharge of the muscle by tilting load were measured before and after the intraperitoneal injection of each drug and compared to those of normal littermates. TRH injection increased spontaneous behavioral activity in RMN and weaver, and shortened the latency of the reflex discharge by tilting load in RMN. Reserpine injection did not increase behavioral activity, but was accompanied by a slight shortening of latencies in the reflex discharge by tilting load only in RMN. L-dopa did not affect behavioral and EMG activities of these cerebellar mutant mice. No remarkable deficit has yet been in any selective intracortical neurons in RMN and no other characteristic abnormality in central and peripheral nervous, skeleton and muscular systems. It was, therefore, suspected that there was a possibility of metabolic disorders of NA in the cerebellum not only in RMN, but also in patients with certain spinocerebellar degenerations.

Animals↗
PubMed1982

Kinetics of the polymerization of hemoglobin in high and low phosphate buffers.

Diluted solutions of deoxyhemoglobin S in concentrated phosphate buffer form aggregates or gels with a clear exhibition of a delay time. The aggregates can be liquified by cooling, bubbling with O2 or CO gas, or the dilution of phosphate buffer with water. These properties can be used as a simple method for studying the mechanism of polymerization and depolymerization of hemoglobins. The advantages of this method are: 1) The amount of hemoglobin sample required is only 1% to 5% of that required for the gelation of deoxy-Hb S in low phosphate buffer. 2) The kinetics can be measured turbidimetrically using an ordinary spectrophotometer. 3) The solubility of hemoglobin can be directly determined by taking the absorption spectrum of the supernatant solution after polymerization. 4) The polymer phase can be easily separated from the solution so that the amount and composition of the polymers can be analyzed. 5) The volume of the polymer phase is so small that excluded volume effect can be neglected. 6) The method can be applied to the study of polymerization of non-sickle hemoglobins and that of mixtures of sickle and non-sickle hemoglobins. The major question is whether the polymerization of hemoglobin in concentrated phosphate buffer is the same as that of deoxy-Hb S in low phosphate buffer. To answer this question, we studied the polymerization of Hb S, Hb A, Hb C Harlem, and Hb C in phosphate buffers of different molarities. We also studied the mechanism of the conversion of gels of these hemoglobins into crystals.

Buffers↗
PubMed1982

Scanning electron microscopy (SEM) studies of the spleen--normal and pathological.

This paper reviews the SEM observations on normal and pathological human spleens. The findings reported by other research groups are briefly introduced. The white pulp is supported by a network of trabecules which may be partly hollow inside and represent a hitherto unknown channel system of highly variable calibers. The marginal zone or the perifollicular red pulp receives much arterial blood from the follicular arteries. The spongy spaces of the marginal zone also contain many lymphocytes. The arterioles in the red pulp open into free spaces in the cords of Billroth. Red cells which have lost plasticity as the result of aging or by taking the shape of stomatocytes and spherocytes in such hematological diseases as hereditary spherocytosis (HS), are interrupted by the narrow slits on the sinus wall, and phagocytosed by patrolling macrophages more easily than normally. SEM images support the view that the particulate matters in blood cells, like intracellular parasites, may be squeezed through the sinus slits ("pitting function") while the cells transit from the cord into the sinus. The sinus rod cells are normally connected with each other by their side processes leaving spindle-shaped slits in between. These rods are adhered together in different pathological conditions, i.e., in hepatosplenic diseases such as hepatic cirrhosis and portal hypertension and in such hematological diseases as HS and idiopathic thrombocytopenic purpura (ITP). Increased thread-like projections of the rods are noticed in these diseases. SEM observations indicate that macrophages are cells which are independent of both reticular and endothelial cells. In most pathological spleens, macrophages are observed to be elevated in phagocytotic activity. They take up erythrocytes vigorously in the spleens of HS and incorporate numerous blood platelets in the cases of ITP.

Erythrocytes↗