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PubMed2002

Counseling and couple therapy for infertile couples.

The article describes a two-tier, interdisciplinary design for the psychological counseling and therapy of childless couples. It is solution- and resource-oriented and avoids psychopathological ascriptions. Couples are supported in coming to terms with the crisis of a physical disorder and its emotional consequences; they are also aided in developing prospects and options for a future without a biological child. The procedure is explained in detail and provides a model suitable for application at reproduction medicine centers and gynecological and andrological practices. Sample interventions illustrate the therapeutic attitude advocated.

Counseling↗

PubMed2005

Genetic variation in G-protein-coupled receptors--consequences for G-protein-coupled receptors as drug targets.

G-protein-coupled receptors (GPCRs), including 'orphan' GPCRs whose natural ligands are unknown, comprise the largest membrane receptor superfamily and are the most commonly used therapeutic targets. GPCR genetic loci harbour numerous variants, such as DNA insertions or deletions and single nucleotide polymorphisms that alter GPCR expression and function, thereby contributing to inter-individual differences in disease susceptibility/progression and drug responses. In this article, the authors review examples of GPCR genetic variants that influence transcription, translation, receptor folding and expression on cell surface (by affecting receptor trafficking, dimerisation, desensitisation/downregulation), or perturb receptor function (by altering ligand binding, G-protein coupling and receptor constitutive activity). In spite of such effects, assessment for genetic variants is not currently applied to the drug development and approval process or in the clinical use of GPCR drugs. Further insights will, the authors believe, alter drug discovery/development, therapeutics and likely provide new GPCR drug targets.

Drug Delivery Systems↗

PubMed1999

Coupling of the expressed cannabinoid CB1 and CB2 receptors to phospholipase C and G protein-coupled inwardly rectifying K+ channels.

Signaling of the cannabinoid CB1 and CB2 receptors through phospholipase C (PLC) and G protein-coupled inwardly rectifying K+ channels (GIRK) was studied after their expression in COS7 cells and Xenopus oocytes. The CB1 or CB2 receptor was co-expressed with alpha subunits of the Galphaq family (Galphaq, Galpha11, Galpha14, Galpha15 and Galpha16) in COS7 cells. Receptor-dependent activation of PLC was observed after co-expressing the CB1 receptor with Galpha14, Galpha15 or Galpha16 but not with Galphaq or Galpha11. Co-expression of Gbeta1 and Ggamma2 abolished the activation, indicating that the activation was mediated by Galpha. PLC activation was not observed when the CB2 receptor was expressed alone or co-expressed with any of the above Galpha subunits. Coupling to GIRK was observed with both CB1 and CB2 receptors after expression in Xenopus oocytes. Significantly larger currents were induced when the receptor was co-expressed with both GIRK1 and GIRK4 than with either GIRK alone. Co-expression of Galpha transducin with the receptor significantly reduced the K+ currents, indicating that GIRK activation was mediated by Gbetagamma but not by Galpha. These findings suggest two new signaling pathways for the cannabinoid receptors.

Animals↗

PubMed2000

Modification of capillaries coupled to micro-flow nebulizers: a new strategy for on-line interference removal in inductively coupled plasma mass spectrometry.

The application of interference removal within modified silica capillaries for the introduction of liquid samples by a micro-flow nebulizer into an inductively coupled plasma quadrupole mass spectrometer is described using the example of (103)Rh and its mass interferences resulting from (63)Cu (ArCu(+)), (87)Rb (RbO(+)), (87)Sr (SrO(+)) and (206)Pb (Pb(2+)). A strong cation exchanger was covalently bound to the capillary surface and its ability to interact with cations in aqueous solution was investigated. At pH 7. 0 the interfering elements can be selectively adsorbed within the capillaries without hampering the elution of Rh. The capillaries are easily regenerated by flushing with 10(-3) M hydrochloric acid in order to exchange retained cations for protons. Calibrations show no significant difference between the absence and presence of interfering elements, so the detection limit for Rh of 6.0 ng l(-1) (3sigma) is not influenced by adding up to a 100-fold excess of interferents. The method developed is compared with a mathematical correction model for inductively coupled plasma mass spectrometry using the example of Rh determination in particulate car exhaust fumes and the results obtained are discussed.

Calibration↗

PubMed1983

Coupling of growth and differentiation in normal myeloid precursors and the breakdown of this coupling in leukemia.

Normal myeloid precursors are dependent on the macrophage and granulocyte growth-inducing protein MGI-1 for cell viability and multiplication. MGI-1 also induces production of the differentiation-inducing protein MGI-2, and this induction of a differentiation-inducing protein by a growth-inducing protein provides a mechanism for the normal coupling of growth and differentiation. It is shown that this induction of MGI-2 by MGI-1 occurs in the myeloid precursors and not in some other cells in the normal bone marrow, that the induced MGI-2 can be detected 6 h after the addition of MGI-1, and that MGI-2 can be induced in these cells by purified MGI-1. There are clones of myeloid leukemic cells that no longer require MGI-1 for cell viability and multiplication, but in which this requirement for MGI-1 can be restored after induction of differentiation by MGI-2. A similar concentration of MGI-1 was required for the optimum induction of growth in these differentiating leukemic cells and in normal myeloid precursors. In the presence of MGI-1 these differentiating leukemic cells multiplied and then lost their differentiation-associated properties. In contrast to normal myeloid cells, MGI-1 did not induce MGI-2 in the MGI-1 requiring differentiating myeloid leukemic cells. This lack of induction of MGI-2 by MGI-1 occurred in cells cultured in serum-containing or serum-free-medium, and can explain the loss of differentiation-associated properties. The results indicate that there has been a genetic breakdown of the normal coupling mechanism between growth and differentiation in these leukemic cells so that MGI-1 can no longer induce MGI-2.

Animals↗

PubMed2004

Simultaneous co-extraction of organometallic species of different elements by accelerated solvent extraction and analysis by inductively coupled plasma mass spectrometry coupled to liquid and gas chromatography.

This paper describes the development of an accelerated solvent extraction methodology that is capable of simultaneously extracting organometallic species of As, Sn and Hg in a semi-automated manner. Accelerated solvent extraction (ASE) methods based on previous research on the separate extraction of organotin and -arsenic species in our laboratory were adapted for the co-extraction of six different species from an oyster tissue certified reference material (BCR 710). For the first time, the extraction of MeHg by this technique is also investigated. The proposed ASE conditions employed 50% acetic acid in methanol at a temperature of 100 degrees C with up to five consecutive extraction cycles of 3 minutes. Extraction efficiencies for organoarsenic species ranged from 80% (dimethylarsinic acid, DMA) to 99% for arsenobetaine (AsB). Species of toxicological interest, such as dibutyltin (DBT), tributyltin (TBT) and methylmercury (MeHg), were extracted with mean recoveries of 81, 84 and 76%, respectively. The extracted species were analysed by gas chromatography/inductively coupled plasma mass spectrometry (GC/ICPMS; DBT, TBT and MeHg) and liquid chromatography/inductively coupled plasma mass spectrometry (LC/ICPMS; MMA, DMA, AsB) after ethylation with sodium tetraethylborate or dilution with water, respectively. In addition to those species for which the extraction efficiency was assessed during this study, a further five arsenic species (arsenite, arsenate and three unidentified species), as well as monobutyltin (MBT) and mono-, di- and triphenyltin, could also be extracted from other matrices. The developed ASE method provides a significant improvement over many currently available routine monitoring methods for trace element speciation due to the fact that it is capable of extracting several species of toxicological interest simultaneously and quantitatively.

Animals↗

PubMed2005

Investigation of the metabolic fate of 2-, 3- and 4-bromobenzoic acids in bile-duct-cannulated rats by inductively coupled plasma mass spectrometry and high-performance liquid chromatography/inductively coupled plasma mass spectrometry/electrospray mass spectrometry.

Inductively coupled plasma mass spectrometry (ICPMS) has been used to determine the rate and routes of excretion of bromine following the intraperitoneal administration (50 mg kg(-1)) of 2-, 3- and 4-bromobenzoic acids to male bile-duct-cannulated rats. Analysis of urine and bile for (79/81)Br using ICPMS showed that all three bromobenzoic acids were rapidly excreted (82-98%) within 48 h of dosing, primarily via the urine. High-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICPMS) was then used to obtain metabolite profiles for bile and urine. These profiles revealed that extensive metabolism had taken place, with the unchanged bromobenzoic acids forming a minor part of the total of compound-related material detected. Concomitant MS studies, supplemented by alkaline hydrolysis, enabled the identification of the major metabolite of all three of the bromobenzoic acids as a glycine conjugate. Ester glucuronide conjugates were also identified, but formed only a small proportion of total.

Animals↗

PubMed2006

Determination of refractory elements in atmospheric particulates using slurry sampling electrothermal vaporization inductively coupled plasma optical emission spectrometry and inductively coupled plasma mass spectrometry with polyvinylidene fluoride as chemical modifier.

Electrothermal vaporization (ETV) inductively coupled plasma optical emission spectrometry (ICP-OES) and inductively coupled plasma mass spectrometry (ICP-MS) with polyvinylidene fluoride (PVDF) as chemical modifier are critically compared for the determination of refractory elements in coal fly ash and airborne particulates. The atmospheric particulates that collected on a PVDF filter were introduced into the graphite furnace in the form of a slurry by dissolving the filter in dimethylformamide, and the dissolved filter PVDF, along with additional added PVDF powder, was used as a chemical modifier for subsequent ETV-ICP-OES and ETV-ICP-MS determination. The vaporization behaviors of analytes (Ti, Zr, V, Mo, Cr, La) in ETV-ICP-OES/MS were studied in detail, and the optimal ETV operating parameters were obtained. Under the optimized operating conditions, the detection limits of target elements were 0.08-2.7 ng m(-3) for ETV-ICP-OES and 0.5-50 pg m(-3) for ETV-ICP-MS, respectively, with analytical precisions of 3.5-7.3% for ETV-ICP-OES and 3.9-9.6% for ETV-ICP-MS, respectively. The tolerable amounts of matrix elements for ETV-ICP-OES are higher than for ETV-ICP-MS. Both ETV-ICP-OES and ETV-ICP-MS were used to directly determine the trace refractory elements in coal fly ash and airborne particulates and the analytical results are comparable.

Journal Article↗

PubMed1997

Inhibition, reactivation, and determination of metal ions in membrane metalloproteases of bacterial origin using high-performance liquid chromatography coupled on-line with inductively coupled plasma mass spectrometry.

High-performance liquid chromatography coupled on-line with inductively coupled plasma mass spectrometry (HPLC-ICP-MS) was used for the characterization of metal ions in several metalloproteases of bacterial origin. The different components of the bacterial extracts were separated on a size-exclusion column. The eluent of the HPLC system was continuously transported to the ICP-MS system for rapid, reproducible, and sensitive analyses of trace elements in the metalloproteases. Two different membrane proteases from Bacillus cereus and Pseudomonas aeruginosa were characterized to be zinc metalloproteases using enzymological methods and HPLC-ICP-MS. The zinc content was determined to be three molecules of zinc per protein molecule for the B. cereus protease and one molecule of zinc per protein molecule for the P. aeruginosa protease. For another purified protease, a periplasmic alanyl aminopeptidase of P. aeruginosa, the lack of protein-bound metal ions could be clearly determined-a confirmation that this main aminopeptidase of P. aeruginosa belongs to the cysteine protease family. The presence of nonionic detergents can influence the distribution of trace elements during the HPLC separation. Therefore, the use of these substances should be avoided during enzyme purification for metal analyses or they should be exchanged later for zwitterionic and ionic detergents with more strongly dissociating properties.

Bacillus cereus↗

PubMed1990

Intercellular dye-coupling in intestinal smooth muscle. Are gap junctions required for intercellular coupling?

The dye Lucifer Yellow was injected into single smooth muscle cells in the guinea pig small intestine in order to study intercellular coupling. Dye-coupling was observed in both the circular and longitudinal muscle layers and was markedly reduced when the intercellular pH was lowered. These results suggest the presence of gap junctions among intestinal muscle cells, but are inconsistent with previous ultrastructural studies that failed to demonstrate such junctions in the longitudinal muscle.

Animals↗

PubMed1994

Inhibitory effects of HgCl2 on excitation-secretion coupling at the motor nerve terminal and excitation-contraction coupling in the muscle cell.

1. Indirect and direct twitch (0.1-Hz) stimulation of the rat phrenic nerve-diaphragm disclosed that the inhibitory effect of HgCl2, 3.7 x 10(-5) M, on the neuromuscular transmission and in the muscle cell, was accelerated by 10-sec periods of 50-Hz tetanic stimulation every 10 min. This activity-dependent enhancement suggested an inhibitory mechanism of HgCl2 related to the development of fatigue, like membrane depolarization or decreased excitability, decreased availability of transmitter, or interference with the factors controlling excitation-secretion coupling of the nerve terminal, i.e. (Ca2+)0 or (Ca2+)i, and excitation-contraction coupling in the muscle cell, i.e., (Ca2+)i. 2. During both indirect and direct stimulation, HgCl2-induced inhibition was enhanced markedly by pretreatment with caffeine, which releases Ca2+ from endoplasmic and sarcoplasmic reticulum in the nerve terminal and muscle cell, respectively. This caffeine-induced enhancement was completely antagonized by dantrolene, which inhibits the caffeine-induced release. However, dantrolene alone did not antagonize the HgCl2-induced inhibition. 3. Since caffeine depletes the intracellular Ca2+ stores of the smooth endoplasmic reticulum, HgCl2 probably inhibits by binding to SH groups of transport proteins conveying the messenger function of (Ca2+)i. In the muscle cell this leads to inhibition of contraction. In the nerve terminal, an additional enhancement of the HgCl2-induced inhibition, by inhibiting reuptake of choline by TEA and tetanic stimulation, suggested that HgCl2 inhibited a (Ca2+)i signal necessary for this limiting factor in resynthesis of acetylcholine. 4. The (Ca2+)0 signal necessary for stimulus-induced release of acetylcholine was not affected by HgCl2. Hyperpolarization in K(+)-free solution antagonized the inhibitory effect of HgCl2 at indirect stimulation, and Ca(2+)-free solution enhanced the inhibitory effect at direct stimulation. K+ depolarization, membrane electric field increase with high Ca2+, membrane stabilization with lidocaine, and half-threshold stimulation, did not change the inhibitory effect of HgCl CH3HgCl. 1.85 x 10(-5) M, disclosed a synergistic interaction with caffeine during direct, but not during indirect, stimulation.

4-Aminopyridine↗

PubMed2002

Comparative analysis of ancient ceramics by neutron activation analysis, inductively coupled plasma-optical-emission spectrometry, inductively coupled plasma-mass spectrometry, and X-ray fluorescence.

The accurate measurement of the maximum possible number of elements in ancient ceramic samples is the main requirement in provenance studies. For this reason neutron activation analysis (NAA) and X-ray fluorescence (XRF) have been successfully used for most of the studies. In this work the analytical performance of inductively coupled plasma-optical-emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) has been compared with that of XRF and NAA for the chemical characterization of archaeological pottery. Correlation coefficients between ICP techniques and XRF or NAA data were generally better than 0.90. The reproducibility of data calculated on a sample prepared and analysed independently ten times was approximately 5% for most of the elements. Results from the ICP techniques were finally evaluated for their capacity to identify the same compositional pottery groups as results from XRF and NAA analysis, by use of multivariate statistics.

Journal Article↗

PubMed2003

Determination of thorium and light rare-earth elements in soil water and its high molecular mass organic fractions by inductively coupled plasma mass spectrometry and on-line-coupled size-exclusion chromatography.

Inductively coupled plasma mass spectrometry (ICP-MS) has been used for the determination of thorium and light rare-earth elements (LREEs) in soil and soil water samples from a mineral deposit (Morro do Ferro, Minas Gerais, Brazil). Size-exclusion chromatography (SEC) on-line coupled to ICP-MS and UV-detection was applied to verify possible association/complexation of these elements with organic matter in soil water separated by a centrifugation technique. Concentrations of DOC in soil waters are in the range of 10 to 500 mg L(-1) and correlate with the organic carbon content of the soil (r=0.950; p<0.001). Concentrations of 30 to 40 microg L(-1) for the LREEs (La, Ce, Nd) and up to 14 microg L(-1) for Th were measured in soil waters of highest DOC content. SEC chromatograms of these waters showed the association of elements with different nominal high-molecular-mass ranges, characteristic of soil humic and fulvic acids: >10,000 Da, with a retention time of about 10 min; 7000 to 8000 Da with retention times of 13 to 15 min; and 2000 to 4000 Da with retention times around 23 min. Elemental peaks associated with dissolved organic matter below 1000 Da were not observed, suggesting that complexation with simple plant organic acids or inorganic ligands is of minor importance in the environment studied in this work.

Journal Article↗

PubMed1990

Metalloprotein separation and analysis by directly coupled size exclusion high-performance liquid chromatography inductively coupled plasma mass spectroscopy.

The feasibility of using directly coupled size exclusion high-performance liquid chromatography inductively coupled plasma mass spectroscopy (HPLC/ICP-MS) for the separation and subsequent elemental analysis of metalloproteins in biological samples has been studied. Data, on up to eight elements, was acquired simultaneously and the reconstructed elemental profiles from the chromatographed samples were quantified by flow injection analysis. Absolute and relative detection limits, reproducibility, operational dynamic range, and linearity of response were initially evaluated by analyzing standards of metallothionein protein of known elemental composition for Cd, Zn, and Cu. There was evidence of displacement of Zn from the protein during chromatography and the substitution of Cu sequestered from the mobile phase. Cd associated with the protein was fully recovered during chromatography. Memory effects, due to protein adsorption to the glassware in the torch box, were minimal and there was no degradation of the resolution of the chromatographed peak during extended transport through the HPLC/ICP-MS interface. The versatility of the technique has been demonstrated by the quantitative multi-element analysis of cytosolic metal-binding proteins separated from the polychaete worm Neanthes arenaceodentata. Fidelity of analysis has been demonstrated by two independent procedures: first, by comparing the elemental profiles obtained by directly aspirating the HPLC eluant into the ICP-MS to those obtained by collecting fractions and quantifying the metal content of the proteins in the conventional analytical mode; second, by comparing the stable isotopic profiles for 114Cd obtained by simultaneous ICP-MS analysis with radiometric profiles of 109Cd obtained by counting radioactivity associated with collected fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Identification of a Gs-protein coupling domain to the beta-adrenoceptor using site-specific synthetic peptides. Carboxyl terminus of Gs alpha is involved in coupling to beta-adrenoceptors.

Competition between Gs-protein and the synthetic peptide, GSA 379-394, derived from the carboxyl-terminal region of the alpha s-subunit, led to complete inhibition of receptor-mediated adenylate cyclase activation in turkey erythrocyte membranes. Related peptides corresponding to the homologous carboxyl-terminal region of alpha t-, alpha il- or alpha o-subunits did not interfere with beta-receptor-Gs coupling. The direct coupling between Gs and adenylate cyclase was not influenced by any of these peptides. These results emphasize the important role of the carboxyl-terminus of G-protein alpha-subunits for the specific recognition of their corresponding receptors and for signal transduction.

Adenylyl Cyclases↗

PubMed1990

Coupling site I and the rotenone-sensitive ubisemiquinone in tightly coupled submitochondrial particles.

The rotenone-sensitive g = 2.00 low temperature EPR signal attributed to ubisemiquinone is observed in submitochondrial particles during coupled electron transfer from NADH to oxygen and from succinate to NAD+. The signal is seen only in the presence of oligomycin added to induce the respiratory control (7-9 with NADH and 3-4 with succinate) and it disappears in the presence of uncouplers (CCCP or gramicidin D). No reduction of the iron-sulfur center N-2 in the presence of 20 mM succinate and cyanide is observed, thus suggesting that N-2 is not in equilibrium with the ubiquinone pool. A hypothesis is proposed on delta mu H+ generation coupled with electron transfer between iron-sulfur center N-2 and the ubiquinone pool.

Carbonyl Cyanide m-Chlorophenyl Hydrazone↗

PubMed1994

Practical applications of element-specific detection by inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry to ion chromatography of foods.

Three practical examples are presented to demonstrate the utility of element-selective detection for ion chromatography (IC). The determination of As species in a liquid health food supplement by IC with inductively coupled plasma atomic emission spectroscopy (IC-ICP-AES) is shown to confirm results obtained for total As. IC-ICP-AES is also used to investigate the identity of an unknown peak in a sample of shrimp commercially treated with tripolyphosphate. Finally, results are presented for the determination of residual bromate in baked goods by IC with inductively coupled plasma mass spectrometry detection.

Animals↗

PubMed1995

Chromium speciation by anion-exchange high-performance liquid chromatography with both inductively coupled plasma atomic emission spectroscopic and inductively coupled plasma mass spectrometric detection.

Development of a new method for the determination of Cr(III) and Cr(VI) is described. Anion-exchange high-performance liquid chromatography (HPLC) was used to separate Cr(III) and Cr(VI) with on-line detection by inductively coupled plasma atomic emission spectroscopy (ICP-AES) at 2766 A in preliminary studies, and inductively coupled plasma mass spectrometry (ICP-MS) with single-ion monitoring at m/z 52 and m/z 53 for final work. A mobile phase consisting of ammonium sulfate and ammonium hydroxide was used, and a simple chelation procedure with EDTA was followed to stabilize the Cr(III) species in standard solutions. ICP-MS results indicated the feasibility of using chromium isotope m/z 53 instead of the more abundant m/z 52 isotope due to a high mobile-phase background most significantly from the SO+ polyatomic interference. The absolute detection limits based on peak-height calculations were 40 pg for Cr(III) and 100 pg for Cr(VI) in aqueous media by HPLC-ICP-MS. The linear dynamic range extended from 5 ppb (ng/ml) to 1 ppm (micrograms/ml) for both species. By HPLC-ICP-AES, detection limits were 100 ng for Cr(III) and 200 ng for Cr(VI). Cr(III) was detected in NIST-SRM 1643c (National Institute of Standards and Technology-Standard Reference Material, Trace Elements in Water) by HPLC-ICP-MS at the 20 ppb level.

Chromatography, High Pressure Liquid↗