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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ionic fluxes and electroneutrality were studied during HCl and fatty acids perfusion through canine Heidenhain pouches. Fatty acids at low concentrations were incapable of modifying the percentages of ionic movements observed during HCl perfusion. In spite fatty acids induced modest signs of gastric mucosal injury like increased disappearance of H+, increased appearance of Na+ in the contents, reduction in potential difference. Results obtained either in the presence or absence of fatty acids showed: 1. at low HCl concentration exchange-diffusion of Na+ for H+ occurred at 1:1 mole basis; 2. at high HCl concentrations increased movement of H+ to blood and decreased movement of Na+ to gastric contents caused a greater diffusion of Cl- out of pouches.
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PMID:[Electroneutrality of the gastric fluids in the dog in vivo with Heidenhain denervated gastric pouches]. 723 83

A retrospective study of illicit phencyclidine (PCP), which consisted of 94 different cases or 213 individual samples, has shown that one third of both the powder/tablets and green plant material contained the synthetic contaminant 1-piperidinocyclohexanecarbonitrile (PCC). The mole % PCC/PCP ranged from 1 to 68%. The method of analysis was gas chromatography (3% OV-7, 205 degrees C) and in preparation for analysis the sample was dissolved directly in chloroform or extracted from a strongly acidic solution (0.1 N HCl). Using these extraction conditions PCC was found not to undergo measurable decomposition.
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PMID:Contamination of illicit phencyclidine with 1-piperidinocyclohexanecarbonitrile. 744 33

An enzyme which cleaves the benzene ring of 3,5-dichlorocatechol has been purified to homogeneity from Pseudomonas cepacia CSV90, grown with 2,4-dichlorophenoxyacetic acid (2,4-D) as the sole carbon source. The enzyme was a nonheme ferric dioxygenase and catalyzed the intradiol cleavage of all the examined catechol derivatives, 3,5-dichlorocatechol having the highest specificity constant of 7.3 microM-1s-1 in an air-saturated buffer. No extradiol-cleaving activity was observed. Thus, the enzyme was designated as 3,5-dichlorocatechol 1,2-dioxygenase. The molecular weight of the native enzyme was ascertained to be 56,000 by light scattering method, while the M(r) value of the enzyme denatured with 6 M guanidine-HCl or sodium dodecyl sulfate was 29,000 or 31,600, respectively, suggesting that the enzyme was a homodimer. The iron content was estimated to be 0.89 mol per mole of enzyme. The enzyme was deep red and exhibited a broad absorption spectrum with a maximum at around 425 nm, which was bleached by sodium dithionite, and shifted to 515 nm upon anaerobic 3,5-dichlorocatechol binding. The catalytic constant and the Km values for 3,5-dichlorocatechol and oxygen were 34.7 s-1 and 4.4 and 652 microM, respectively, at pH 8 and 25 degrees C. Some heavy metal ions, chelating agents and sulfhydryl reagents inhibited the activity. The NH2-terminal sequence was determined up to 44 amino acid residues and compared with those of the other catechol dioxygenases previously reported.
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PMID:Purification of 3,5-dichlorocatechol 1,2-dioxygenase, a nonheme iron dioxygenase and a key enzyme in the biodegradation of a herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), from Pseudomonas cepacia CSV90. 767 68

We have recently shown that the major proteins from bovine seminal plasma, namely BSP-A1, BSP-A2, BSP-A3, and BSP-30-kDa (collectively called BSP proteins) are novel phospholipid-binding proteins. These proteins show a Ca(2+)-independent interaction with phosphorylcholine (PrC) containing lipids and this group acts as a specific binding site for BSP proteins on the sperm membrane. In this study, we investigated the biochemical basis of the binding of BSP proteins to the phosphorylcholine moiety using different affinity chromatography matrices containing active groups analogous to PrC. Proteins from bovine seminal fluid were applied to a column containing p-aminophenyl phosphorylcholine coupled to Agarose (PPC-agarose). Unadsorbed proteins were washed out with buffer (Tris-HCl) and elution of bound proteins was assessed with the same buffer containing different eluting agents. The adsorbed proteins were eluted with buffer containing specific (PrC or choline chloride), denaturing agent (urea), or chaotropic agent (sodium thiocyanate) and identified as BSP proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. At high ionic strength, these proteins could also be adsorbed on quaternary methylamine coupled to silica and diethylaminoethyl coupled to Sephadex and were eluted specifically with phosphorylcholine, choline chloride, or urea. These data suggest a structure-dependent hydrophobic interaction of the ligands with BSP proteins. Furthermore, binding experiments using equilibrium dialysis indicated that there are two choline binding sites per mole of protein. In addition, the combination of affinity chromatography columns and linear gradient of eluting agents allowed the complete fractionation of the different BSP proteins. The availability of an affinity chromatography method should aid in those studies aimed toward the understanding of the physiology of these phospholipid-binding proteins.
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PMID:Interaction of a novel class of phospholipid-binding proteins of bovine seminal fluid with different affinity matrices. 837 72

Under nondenaturing conditions, 1 mol of horse plasma gelsolin reacts with 1.9 +/- 0.5 mol (mean +/- SD, n = 6) of the sulfhydryl-specific fluorescent reagent 6-acryloyl-2-dimethylaminonaphthalene (acrylodan). The degree of labeling in 6 M guanidine-HCl increases to about 3 mol of acrylodan per mole of gelsolin. Viscosity studies show that the modified gelsolin retains its ability to sever F-actin filaments. Circular dichroism spectra in the peptide bond absorption region are indistinguishable for labeled and unmodified gelsolin at room temperature. The thermal stability of gelsolin, as monitored by circular dichroism, is unaffected by reaction with acrylodan. While circular dichroism spectra of acrylodan-labeled gelsolin recorded at room temperature are not influenced significantly by Ca2+, fluorescence studies reveal a number of Ca(2+)-dependent changes in the protein. Ca2+ causes a decrease and red-shift in fluorescence emission, an increase in sensitivity to quenching by I-, and a decrease in polarization of the fluorescence of acrylodan-labeled gelsolin. Together, these changes in fluorescence properties indicate there to be an increased exposure of the label to the solvent when gelsolin binds Ca2+. Fluorescence polarization experiments in which acrylodan-labeled gelsolin is titrated with actin emphasize that Ca2+ is required for these two proteins to interact.
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PMID:Fluorescent responses of acrylodan-labeled plasma gelsolin. 838 3

The pH of concentrated NaCl-HCl fluids (0.57 mole of NaCl per kilogram of water) has been measured at supercritical conditions of water with a yttria-stabilized zirconia sensor in a titanium flow reactor. At 400°C and 40 megapascals, the in situ pH of the fluids, ranging from 3.3 to 6.2, differs greatly from its original value of 1.9 to 7.6 at ambient conditions. The measurements agree well with theoretical predictions, showing strong associations of HCl° and NaOH° complexes in high-temperature fluids. The pH sensor provides a powerful tool to investigate unambiguously the distribution of species in aqueous fluids at elevated temperatures and pressures.
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PMID:Direct pH Measurement of NaCl-Bearing Fluid with an in Situ Sensor at 400°C and 40 Megapascals 866 75

The role of reactive oxygen species in causing DNA damage through interaction of chromium (III) and hydrogen peroxide was examined using plasmid relaxation assay and EPR spectroscopy. Marked DNA strand breakage was induced by CrCl3 plus H2O2 in a phosphate buffer at pH 6-8.9; whereas, only slight DNA strand breakage was observed during similar treatment at pH less than 4. DNA breakage also increased as the reaction temperature and Cr(III)/H2O2 concentrations increased. Control experiments with Cr(III) or H2O2 alone did not cause DNA breakage. Sodium azide, D-mannitol, Tris-HCl, or catalase completely inhibited Cr(III)/H2O2-induced DNA breakage, but superoxide dismutase did not. The D2O enhancing effect on DNA breaks was not observed. Cr(III) pre-incubated with a 30-fold molar excess of EDTA did not cause any significant DNA breakage in the presence of H2O2. In a phosphate buffer containing Cr(III) and H2O2, singlet oxygen and hydroxyl radicals were detected using EPR spectrometry with the spin traps 2,2,6,6-tetramethyl-4-piperidone and 5,5-dimethyl-1-pyrroline 1-oxide (DMPO), respectively. DMPO/.OH adducts and DNA breakage induced by Cr(III)/H2O2 were markedly higher than those induced by Cr(VI)/H2O2. Furthermore, ascorbate decreased Cr(III)/H2O2-induced DNA breakage. EPR studies revealed that ascorbate (mole ratio to Cr(III) = 0.5:1) attenuated the DMPO/.OH signal generated by Cr(III)/H2O2/DMPO, but a Cr(V) signal and ascorbate radicals were detected. NADPH, GSH, and GSSG also decreased DMPO/.OH generated by Cr(III)/H2O2/DMPO; however, they were less efficient than ascorbate and no Cr(V) signals were detected. This study shows that Cr(III)/H2O2 generates oxidative damage to DNA through a Fenton-like reaction: Cr(III) + H2O2-->Cr(IV) + .OH + OH.
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PMID:Formation of reactive oxygen species and DNA strand breakage during interaction of chromium (III) and hydrogen peroxide in vitro: evidence for a chromium (III)-mediated Fenton-like reaction. 902 Nov 67

119Sn NMR spectroscopy was employed for analysis of the interaction and reaction of SnCl4 with the HCl-IBVE adduct [1; CH3CHCl(OiBu)] in the presence of nBu4NCl in CH2Cl2 solution at -78 degreesC, which are model reactions for the living cationic polymerization of isobutyl vinyl ether (IBVE). The addition of 1 to an SnCl4 solution led to upfield shifts of the tin nucleus as the 1/SnCl4 mole ratio (<1) increases, which indicates the formation of SnCl5-, via the interaction between SnCl4 and the chlorine atom in 1. On further addition of 1, the pentacoordinated anion is converted into the hexacoordinated SnCl62-. These tin species are in fast equilibrium among each other, and the 119Sn NMR analyses support the formation of a carbocation [2; CH3CH+(OiBu)] from 1 and the dynamic equilibrium between 1 and 2. More effective chloride-anion donors such as nBu4NCl and Ph3CCl can quantitatively convert SnCl4 into SnCl5-, and then into SnCl62-. Thus under the conditions where living cationic IBVE polymerization proceeds (1 < nBu4NCl/SnCl4 < 2), SnCl4 is fully converted into a weaker Lewis acid, SnCl5-, with the aid of added nBu4NCl. The suppression of the carbocationic species in the living system has thus been found due to the interaction between the added salt and SnCl4.
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PMID:In-Situ Direct Analysis of the Growing Species by 119Sn NMR Spectroscopy: Living Cationic Polymerization of Isobutyl Vinyl Ether with HCl/SnCl4/nBu4NCl1 968 Apr 2

It was established in the experiments determining the influence of the mushroom powder on acidity of the HCl solution by means of ionometrical method that in 15 minutes after introduction 3 gram of the powder pH of the solution increases from 1.62 up to 2.64. The stable meaning of the solution pH (without fall) can be (held) the same in the presence of the powder more than 23 hours. The mushroom powder reduces the high content of the ions Pb2+ and Cu2+ in the solution from 8.8 x 10(-6) up to 3.3 x 10(-6) and from 11.8 x 10(-6) up to 8.6 x 10(-6) mole/ml correspondingly. The trustworthy reduction (fall) of the concentration of the ions Zn2+ and Cd2+ in the filtrate was not discovered (found out). To determine the content of metal in the solution the method of flaming atomic adsorption.
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PMID:[Antacid and sorption properties of mushroom powder made of dried solids (Pleurotus ostreatus)]. 1064 Dec 77

The E isomer of (123)I-2beta-carbomethoxy-3beta-(4-fluorophenyl)-N-(1-iodoprop-1-en-3-yl)nortropane (Altropane(R)) shows high affinity (IC(50) = 6.62 +/- 0.78 nmol) and selectivity (DA/5-HT = 25) for DAT sites in the striatum. Recently, dynamic SPECT studies in healthy volunteers and patients with Parkinson disease demonstrated that the kinetics of striatal accumulation followed a pattern that is characteristic of a reversible tracer with maximal accumulation within 30 min after injection. These findings suggested that radiolabeling Altropane with [(11)C] might provide an equivalent and complementary tracer for PET studies. [(127)I] Altropane was treated with HCl to hydrolyze the methyl ester bond and yield a precursor for [(11)C] labeling. Introduction of an [(11)C] methyl ester group was achieved by treatment with [(11)C] CH(3)I followed by HPLC purification. Five healthy rhesus monkeys were injected with approximately 10 mCi of [(127)I,(11)C] Altropane and dynamic PET images were acquired over 90 min. Arterial blood samples were collected in parallel with imaging and metabolite analysis was performed by HPLC. The PET and metabolite corrected arterial blood data were to calculate k(3)/k(4) by two methods: 1) nonlinear least-squares fitting, and 2) a linear graphical method for reversible ligands. The synthetic procedure yielded high specific activity tracer, >1,000 mCi/micro mole, with radiochemical purity >95%. Synthesis time was approximately 30 min. The PET images revealed excellent striatal definition, with clear separation of caudate nucleus and putamen and minimal accumulation in brain regions with high 5HT transporter density. Metabolite analysis demonstrated that at 60 min after injection, approximately 80% of circulating tracer was intact [(127)I,(11)C] Altropane and the remainder was converted to polar metabolites. Values for k(3)/k(4) calculated by two analysis methods were remarkably similar: Method 1, 3.48 +/- 0.41; Method 2, 3.77 +/- 0.45 (mean +/- SEM, t = 2.31, df = 8, P = 0.64). These results establish that Altropane has the important characteristics of: 1) rapid and specific striatal binding; 2) high selectivity for DA vs. 5-HT transporter sites; 3) reversible binding kinetics; 4) potential for multiple injection studies; 5) high efficiency labeling with either [(11)C] or [(123)I]; 6) applicability for both PET and SPECT. These properties make Altropane an important DAT ligand for both research and clinical applications.
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PMID:[(11)C, (127)I] Altropane: a highly selective ligand for PET imaging of dopamine transporter sites. 1116 84


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