[5-Hydroxyindole acetic acid assay and the clinical significance].
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Anorexia Nervosa↗
Biomedical subjects
C Tanaka
Publications and source records attributed to C Tanaka.
Regulatory role of enteric mu and kappa opioid receptors in the release of acetylcholine and norepinephrine from guinea pig ileum.
We examined the role of opioid receptor subtypes in the contraction and release of acetylcholine (ACh) and norepinephrine in longitudinal muscle-myenteric plexus preparations of the guinea pig ileum. [D-Ala2, N-Me-Phe4, Gly5-ol]enkephalin (DAMGO) (10(-8) to 10(-5) M) inhibited the contraction and the release of ACh evoked by 0.2 and 1 Hz of electrical stimulation (ES), whereas the response to 5 Hz was enhanced by low concentrations of DAMGO (10(-9) to 10(-8) M) and inhibited by high concentrations (10(-7) to 10(-5) M); naloxone antagonized these effects. In preparations treated with yohimbine, DAMGO inhibited the ES (5 Hz)-evoked contraction and ACh release, but failed to enhance either effect. Dynorphin-A inhibited the contraction and ACh release evoked by 0.2, 1 and 5 Hz of ES, and the effect of dynorphin-A was mimicked by U-69593 [5 alpha,7 alpha,8 beta-(-)-N-methyl-N-[7- (pyrrolinyl)-1-ozaspiro(4,5)dec-8-yl]-benzene] and antagonized by MR 2266 [(-)-alpha-5,9-diethyl-2-(3-furylmethyl)-2'-hydroxy-6,7-benzomorphan]. The release of norepinephrine evoked by 5 Hz of ES was inhibited by DAMGO (10(-10) to 10(-6) M), but not by U-69593, and the effect of DAMGO was antagonized by naloxone. Thus, it would appear that mu-opioid receptors are present on both cholinergic and adrenergic neurons, whereas kappa-opioid receptors are present on cholinergic neurons. The affinity of DAMGO was 30 times higher for the mu-opioid receptors on the adrenergic than on the cholinergic neurons.(ABSTRACT TRUNCATED AT 250 WORDS)
Acetylcholine↗
Involvement of the gamma subtype of protein kinase C in GABA release from the cerebellum.
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Animals↗
[A case of evaluation of hepatic hemangioma on phosphorus 31 magnetic resonance spectroscopy (31P-MRS)].
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Adult↗
Mechanism of contractile response to bombesin of the longitudinal muscle from guinea pig ileum.
The mechanism of action of bombesin in the longitudinal muscle with myenteric plexus (LM-MP) preparation from guinea pig ileum was examined. Bombesin (3 x 10(-10) to 3 X 10(-7) M) induced contraction in a concentration-dependent manner. The contractions induced by bombesin at concentrations of 10(-9) M and less were tetrodotoxin- and scopolamine-sensitive, and those induced at concentrations of 10(-8) M and greater were tetrodotoxin-sensitive, and partially scopolamine-sensitive. In association with the mechanical response to bombesin, the peptide induced Ca(++)-dependent and tetrodotoxin-sensitive release of acetylcholine from the LM-MP preparation. Bicuculine inhibited partly both the cholinergic contraction and the release of acetylcholine induced by bombesin, suggesting the involvement of a gamma-aminobutyric acid (GABA)-ergic mechanism. Bombesin also induced Ca(++)-dependent and tetrodotoxin-sensitive release of endogenous and [3H]GABA from the LM-MP preparation. These results indicate that bombesin induces contraction mainly mediated mediated by cholinergic and partially mediated by noncholinergic excitatory neurons. GABAergic neurons may be involved in a part of the response to bombesin mediated by the cholinergic neuron.
Acetylcholine↗
[Plasma serotonin assay and the clinical significance].
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Carcinoid Tumor↗
Evidence for a second isoform of the catalytic subunit of calmodulin-dependent protein phosphatase (calcineurin A).
We have used a previously characterized rat cDNA clone for the catalytic (A) subunit of calmodulin-dependent protein phosphatase (calcineurin), which we designated A alpha, to isolate cDNA clones coding for a second isoform of the A subunit, A beta. The A beta cDNA encodes a protein of 525 amino acids that is 81% identical with A alpha. The N-terminal region is dissimilar and contains a characteristic proline-rich sequence. The region homologous to protein phosphatases 1 and 2A (region between residues 87 and 338, 91% identical) and the calmodulin binding domain (region between residues 401 and 424, 96% identical) are highly conserved. The presence of two genes coding for calcineurin A suggests the possibility of important functional differences in the two enzymes.
Amino Acid Sequence↗
The complete primary structure of calcineurin A, a calmodulin binding protein homologous with protein phosphatases 1 and 2A.
A complementary DNA (cDNA) clone encoding the catalytic subunit of calcineurin (calcineurin A) has been isolated from a rat brain cDNA library. The primary structure of the cDNA consists of 2,337 nucleotides including the entire coding region for 521 amino acids, and the calculated molecular mass is 58,643 Da. The calcineurin A is strikingly homologous to protein phosphatases 1 and 2A, approximately 50% of the amino acids over an internal 250-residue region between residues 78 and 329 being identical. Twenty four amino acid-residue region between residues 391 and 414 shows the consensus structural features for a calmodulin-binding domain. These data suggest that the allosteric character of this chimeric enzyme is generated by gene fusion of two separate protein families.
Amino Acid Sequence↗
Activation of type I cyclic AMP-dependent protein kinases is impaired by a point mutation in cyclic AMP binding sites.
The type I regulatory (R-I) subunit of cyclic AMP-dependent protein kinase (A-kinase) was expressed in E. coli, and a single amino acid substitution in cyclic AMP binding sites A or B was introduced by site-directed mutagenesis. The cyclic AMP binding activity and cyclic AMP-stimulated phosphotransferase activity of the holoenzymes formed by wild-type or mutant R-Is and the purified bovine catalytic subunit of A-kinase were then examined. The wild-type holoenzyme was activated by low concentrations of cyclic AMP, a finding in accord with its high-affinity binding to cyclic AMP. In contrast, although the two mutant holoenzymes showed high-affinity cyclic AMP binding at their non-mutated sites, both holoenzymes were resistant to activation by cyclic AMP. Thus, binding of cyclic AMP to the non-mutated cyclic AMP binding site is not sufficient to dissociate the catalytic subunit from the mutant R-Is upon cyclic AMP binding. These results suggest that both A and B cyclic AMP binding sites are required for efficient coupling between cyclic AMP binding and activation of the enzyme.
8-Bromo Cyclic Adenosine Monophosphate↗
Involvement of protein kinase C in the Ca2+-dependent vesicular release of GABA from central and enteric neurons of the guinea pig.
The involvement of protein kinase C (PKC) in the release of endogenous gamma-aminobutyric acid (GABA) was studied using slices of deep cerebellar nucleus and strips of small intestine from the guinea pig. 12-O-tetradecanoylphorbol 13-acetate (TPA), but not 4 alpha-phorbol-12,13-didecanoate (4 alpha-PDD), potentiated the high K+-evoked release of GABA from both preparations in the presence of tetrodotoxin. Ouabain evoked the release of GABA from both preparations, and this release was not altered by TPA. Therefore, the activation of protein kinase C potentiates the Ca2+-dependent vesicular release of GABA from nerve terminals of the central and enteric GABAergic neurons of the guinea pig.
Animals↗
High-performance liquid chromatographic/mass spectrometric and high-performance liquid chromatographic/tandem mass spectrometric analysis of carbamate pesticides.
The thermospray ionization mass spectra of selected carbamate pesticides were obtained using both single-stage and triple-stage quadrupole mass spectrometry in conjunction with high-performance liquid chromatography. With the use of the single-quadrupole mass spectrometer and ammonium acetate as the mobile phase, enhanced sensitivity for the analytes of interest was obtained by monitoring the relatively intact [M + 1]+ or [M + 18]+ adduct ions. Further structural characterization of the carbamates was not readily obtainable owing to the lack of diagnostic bond cleavages. The single-stage quadrupole analyses were therefore complemented by triple-stage quadrupole analyses. Here, collisionally activated daughter ion spectra exhibited structure-specific fragmentations. In addition, the enhanced selectivity and specificity provided by tandem mass spectrometry allowed use of the technique as a rapid screening tool for carbamates without the need for the chromatographic separation step.
Carbamates↗
Phorbol ester binding sites in human brain: characterization, regional distribution, age-correlation, and alterations in Parkinson's disease.
We have characterized and localized phorbol ester binding sites in human autopsied brains, using [3H]phorbol 12,13-dibutyrate ([3H]PDBu). When the tissue was homogenized in the absence of Ca2+ chelator (10 mM EGTA/2 mM EDTA), Scatchard analysis of the specific [3H]PDBu bindings to both particulate and soluble fractions yielded a single class of high-affinity binding site (Kd = 7.1 and 7.4 nM: Bmax = 45.4 and 3.1 pmol/mg protein, respectively). The particulate fraction retained the majority of [3H]PDBu binding (98% of total binding activity), while the soluble fraction was almost devoid of binding activity (2%). In the presence of Ca2+ chelator, more of the activity was found in the soluble fraction (30%). The binding of [3H]PDBu was potently inhibited by active phorbol esters and related diterpenes with Ki of nanomolar concentration but not by inactive ones. Diolein (OAG), a synthetic diacylglycerol, and polymixin B, an inhibitor of protein kinase C (PKC), inhibited the binding moderately (Ki = 5.8 and 1.3 microM, respectively). H-7, an inhibitor of PKC and cyclic nucleotides-dependent kinase, did not compete with [3H]PDBu for the binding sites (Ki greater than 100,000 nM). The regional distribution of specific [3H]PDBu binding in the human brain was rather uneven and resembled that of [3H]PDBu autoradiograms and PKC-like immunoreactivities in the rat brain. The binding capacities were generally in the order: rhinencephalon greater than basal ganglia greater than cerebral cortex greater than diencephalon greater than cerebellum greater than mesencephalon. Age-related loss of binding sites was observed in the prefrontal cortex of the subjects 33-81 years of age. In Parkinson's disease, the phorbol ester binding showed a significant reduction in the substantia nigra, caudate putamen, and pallidum, whereas it was unchanged in the prefrontal cortex and caudate nucleus of schizophrenics, when compared with the relevant controls.
Adult↗
Inositol 1,4,5-trisphosphate binding sites in the brain: regional distribution, characterization, and alterations in brains of patients with Parkinson's disease.
[3H]Inositol 1,4,5-trisphosphate [( 3H]Ins-(1,4,5)P3) binding studies were done on the human brain obtained at autopsy. The specific [3H]Ins(1,3,4,5)P3 binding sites in the cerebral and cerebellar cortices consisted of a single component with a high affinity (Kd = 11.3 and 16.5 nM, Bmax = 0.8 and 6.4 pmol/mg protein, respectively). The binding of [3H]Ins(1,4,5)P3 was potently inhibited by Ins(1,4,5)P3, in a nanomolar concentration, while other inositol phosphates and inositol were either much less potent or did not inhibit binding. The binding sites for [3H]Ins(1,4,5)P3 were discretely localized and were in the order: cerebellum much greater than basal ganglia, cerebral cortex greater than rhinencephalon greater than diencephalon, mesencephalon. There was an age-related loss of [3H]Ins(1,4,5)P3 binding in the frontal cortex. In the brains of patients with Parkinson's disease, [3H]Ins(1,4,5)P3 binding sites were reduced by about 50% in the caudate nucleus, putamen, and pallidum, while there were no differences in the frontal cortex, as compared to findings in the age-matched controls. Our findings suggest that [3H]Ins(1,4,5)P3 binding sites are closely linked to neural elements in the human brain.
Binding, Competitive↗
Partial characterization of testosterone 5 alpha-reductase solubilized from rat testicular microsomes.
Testosterone 5 alpha-reductase was successfully solubilized by the use of digitonin from rat testicular microsomes and then partially purified by polyethylene glycol fractionation and DEAE-Sephacel column chromatography. The 5 alpha-reductase activity of the partially purified preparation was significantly stimulated by addition of phosphatidylserine (bovine brain). Synthetic dilauroylphosphatidylcholine also increased the reductase activity to a somewhat lesser extent than did phosphatidylserine, whereas natural phosphatidylcholine from bovine liver did not exhibit any stimulation. When synthetic phosphatidylcholines with varying acyl chain lengths were tested for their stimulatory effects on the reductase activity, dilauroylphosphatidylcholine was most active; dimyristoylphosphatidylcholine was less active; dioleoylphosphatidylcholine was almost inactive.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Progesterone metabolism in the gastric mucosa microsomes of guinea pig.
The microsomes from guinea pig gastric mucosa were found to convert [4-14C]progesterone to two major metabolites in the presence of NADPH. The gastric metabolizing activity was the highest among the gastrointestinal tissues of guinea pig. 5 alpha-Pregnane-3,20-dione and 3 beta-hydroxy-5 alpha-pregnan-20-one were identified as the major metabolites by thin-layer chromatography and crystallization to constant specific activity, suggesting the presence of steroid 5 alpha-reductase and 3 beta-hydroxysteroid dehydrogenase activities in the gastric mucosa microsomes. Furthermore, time course of progesterone metabolism and analysis of 5 alpha-pregnane-3,20-dione metabolites suggest that the gastric progesterone metabolism is initiated by 5 alpha-reductase and followed by 3 beta-hydroxysteroid dehydrogenase. The progesterone-metabolizing activity was strongly inhibited by SKF 525-A and disulfiram. The activity was also inhibited by methyrapone to a somewhat lesser extent than the above inhibitors. From gastric mucosa microsomes, the progesterone-metabolizing activity was successfully solubilized with 2% digitonin using 0.1 M potassium chloride and 1 mM dithiothreitol, 0.4 mM NADPH and 20% glycerol as stabilizers for the solubilized activity. Among these stabilizers, glycerol was found to be most effective for stabilizing the activity of the solubilized microsomes.
17-Hydroxysteroid Dehydrogenases↗
Magnetic resonance imaging of brain contusion.
In this study we investigated the time course of brain contusions using magnetic resonance imaging and compared the findings with those of a computed tomography scan. The lesions, which were demonstrated as homogeneous density areas on the computed tomography scan were demonstrated as different intensity areas in the magnetic resonance image. The intensity of the images varied according to the time at which the images were obtained. The findings indicated changes in the nature of the contusions including hematoma hemoglobin, perifocal edema extension, and so on. In conclusion, magnetic resonance imaging is important in the follow-up of chronological change as well as in original diagnosis of brain contusions.
Adolescent↗
Growth and electric current loops in plants.
A theory is presented for a relationship between ion accumulation and electric current loops in multicellular systems such as the roots and stems of higher plants. A network of electric circuits shows that the electric current transported across the cell membrane flows between an elongating region and a mature region, not only in roots but also in stems. In roots, ions constituting the extracellular electric current flow in the external aqueous medium, while in stems an electric current of comparable density flows within the epidermal cell wall. Based on this theoretical result, electric isolation between the elongating and mature regions was made in the case of both roots and stems. The speed of growth during the initial stage was greatly decreased due to a change in the distribution of protons around the surfaces of the plant by cutting off the electric current loop. Electrochemical calculation shows that ions are not always accumulated at the efflux site, since the ion distribution is strongly affected by the relation of the magnitudes between the electric field and electric current. The results calculated for the electric potential and pH distributions around the root agree with experimental data.
Journal Article↗
Design, synthesis and 64Cu labeling of fatty acid analogs containing dithiosemicarbazone chelate.
For the development of 62Cu labeled fatty acid analogs, two fatty acid analogs, containing dithiosemicarbazone (DTS) molecule as the 62Cu coordinating site, were designed and synthesized: a fatty acid analog containing DTS molecule at the omega-position, (a) the 12,13-dioxotetradecanoic acid di(N-methyl-thiosemicarbazone) (FA-DTS), and an omega-phenyl fatty acid analog containing DTS molecule at the para-position, (b) the p-carboxyundecylphenylglyoxal-di (N-methylthiosemicarbazone] (PFA-DTS). FA-DTS was synthesized by the reaction of ethyl diethoxyacetate with ethyl 11-bromonundecanate by successive decarboxylation and hydrolysis and final condensation with N-methylthiosemicarbazide. PFA-DTS was synthesized by the Friedel-Craft acylation of ethyl 11-phenylundecanate, selenium oxidation of the acetophenone derivative, followed by the condensation with N-methylthiosemicarbazide. Radiolabeling of FA-DTS and PFA-DTS with [64Cu]copper acetate was simple, rapid and quantitative. When injected into mice, both compounds were distributed and retained in the myocardium. These results offer a good basis for further development of 62Cu labeled fatty acid analogs.
Animals↗