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Showing papers on "Fluorescence spectrometry published in 1983"


Journal ArticleDOI
TL;DR: A detailed description of the construction and performance of a variable frequency cross-correlation phase fluorometer is reported and some application to the measurement of multiexponential decays is illustrated.

498 citations


Journal ArticleDOI
TL;DR: The time course of H2O2 release by mouse peritoneal and bone marrow-derived macrophages and by human neutrophils was determined following stimulation with zymosan particles or phorbol myristate acetate, and the dependence of H1N1 release on cell number and stimulus dosage was studied.

272 citations


Journal ArticleDOI
TL;DR: In this paper, the authors measured the thermal averaged cross sections σQ for collisional quenching of the A 2 ε+ state of the OH molecule near 1100 K. The experimental results have been compared with a theoretical calculation based on multipole attractive forces with a repulsive centrifugal barrier.
Abstract: Thermally averaged cross sections σQ for collisional quenching of the A 2Σ+ state of the OH molecule have been measured near 1100 K. The OH was produced and detected in a laser pyrolysis/laser fluorescence experiment, in which a mixture of SF6, H2O2, and the collision partner M was heated by a pulsed CO2 laser. Thermal decomposition of the peroxide produces OH which is then excited by a tunable laser; the real‐time decay of the fluorescence signal at different pressures of M furnishes σQ. These σQ at elevated temperatures are generally less than the room temperature values. This result, the size of σQ, and its variation with M suggest the importance of attractive forces in the collisional quenching. The experimental results have been compared with a theoretical calculation of σQ based on multipole attractive forces with a repulsive centrifugal barrier. Good correlation is obtained for eight of the 11 quenchers studied; the experimental values of σQ for N2 and SF6 are conspicuously low.

191 citations


Journal ArticleDOI
TL;DR: Provided Ca2+ is present, the interaction between the two peptides leads to significant changes in the environment of at least one tyrosine residue of calmodulin as measured by near-UV circular dichroism.
Abstract: In the presence of Ca2+, calmodulin forms a 1:1 high-affinity complex (Kd = 3 nM) with melittin, a peptide from bee venom; in the presence of ethylenediaminetetraacetic acid, a second type of complex, of much lower affinity, is formed [Comte, M., Maulet, Y., & Cox, J. A. (1983) Biochem. J. 209, 269-272]. In this paper, these interactions were studied by tryptophan fluorescence and circular dichroism spectroscopy in near- and far-UV. Interaction between the two peptides in the presence as well as in the absence of Ca2+ leads to the shielding of the tryptophan residue of melittin from its aqueous environment and to an increase in the alpha-helical content of bound melittin; for instance the Ca2+-dependent high-affinity complex formation enhances the alpha-helical content of melittin from 5 to 72%. Provided Ca2+ is present, the interaction between the two peptides leads to significant changes in the environment of at least one tyrosine residue of calmodulin as measured by near-UV circular dichroism. In the absence of Ca2+, calmodulin binds two melittin molecules with a Kd of ca. 10 microM; at higher concentrations of free melittin, additional binding occurs (up to 5 mol of melittin/mol of calmodulin), with concomitant denaturation of calmodulin. In the presence of 4.0 M urea, the low-affinity complexes formed in the absence of Ca2+ dissociate, due to the denaturation of metal-free calmodulin, whereas the spectroscopic signals of the high-affinity Ca2+-dependent complex are not affected.(ABSTRACT TRUNCATED AT 250 WORDS)

170 citations


Journal Article
TL;DR: In intraarterial administration of cis-diamminedichloroplatinum results in increased drug exposure of tumor in the infused area without substantially decreasing exposure of systemic tumor.
Abstract: After intraarterial (30 patients) or iv (seven patients) administration of cis -diamminedichloroplatinum, X-ray fluorescence spectrometry was used to measure platinum concentrations in plasma and urine Arteries infused included hepatic (seven patients), carotid (six patients), iliac (ten patients), brachial (three patients), and femoral (four patients) All patients received iv mannitol Pharmacokinetic parameters after intraarterial administration were similar to those after iv administration, although differences existed for different intraarterial routes of administration Mean for all patients combined were: C , 267 ± 097(SD) µ g/ml; t ½ β , 711 ± 266 hr; clearance, 072 ± 025 liters/hr/sq m; total volume of distribution, 452 ± 170 liters/sq m; C × t , 167 ± 72 mg/hr/liter; and 24-hr urinary excretion, 20 ± 10% of the administered dose Intrahepatic infusion of the drug was associated with a significantly lower C (188 ± 050 g/ml) and C × t (140 ± 25 mg hr/liter) and significantly higher clearance (091 ± 024 liters/hr/sq m) and volume of distribution (676 ± 46 liters/sq m) than administration by other routes, suggesting first pass extraction of drug by liver In addition, an apparent minor late rise in serum platinum concentration may suggest enterohepatic recirculation of drug High fluid intake was associated with a low C and a high volume of distribution, consistent with expansion of the central compartment by fluids Low serum albumin (<35 g/dl) was associated with significant shortening of the t ½ β (505 ± 216 hr), suggesting that the amount of unbound filterable drug may possibly be higher in patients with low serum albumin concentrations Plasma from veins draining an infused area has a higher C and C × t during infusion than concurrent plasma from peripheral veins Thus, intraarterial administration of cis -diamminedichloroplatinum results in increased drug exposure of tumor in the infused area without substantially decreasing exposure of systemic tumor

140 citations


Journal ArticleDOI
TL;DR: Sedimentation velocity experiments on daunomycin-deoxypolynucleotide complexes show an unusual nonlinear dependence of Sapp on the binding ratio for poly[d(A-T)] X poly[ d(a-T)], poly[D(G-C)] X Poly(dA) X poly(dT), indicative of either a nonstandard conformational change accompanying intercalation or cooperative drug binding.
Abstract: Fluorescence and absorbance methods were used to study the interaction of daunomycin with four deoxypolynucleotides. The binding may be described by the neighbor-exclusion model for binding ratios greater than 0.05, with intrinsic binding constants decreasing in the order poly[d(A-T)] X poly[d(A-T)] greater than poly[d(G-C)] X poly[d(G-C)] greater than poly(dG) X poly(dC) greater than poly(dA) X poly(dT). The exclusion parameter was found to be approximately 2 for the A-T-containing polynucleotides, 4 for the alternating G-C polymer, and nearly 10 for poly(dG) X poly(dC). Poly(dA) X poly(dT) showed positive cooperativity at low binding ratios. Thermal denaturation studies provided quantitative support for the measured binding parameters; the delta Tm values measured may be correlated primarily with the differences seen in the exclusion parameter. Sedimentation velocity experiments on daunomycin-deoxypolynucleotide complexes show an unusual nonlinear dependence of Sapp on the binding ratio for poly[d(A-T)] X poly[d(A-T)], poly[d(G-C)] X poly[d(G-C)], and poly(dA) X poly(dT), indicative of either a nonstandard conformational change accompanying intercalation or cooperative drug binding.

116 citations


Journal ArticleDOI
TL;DR: On adding PHMB, the fluorescence polarization of diphenylhexatriene embedded in the negatively charged bilayers was reduced to a great extent, especially in the gel phase, interpreted in terms of PHMB-induced expansion and fluidization of the bilayer, which enables the probe molecule to undergo less-hindered torsional motion.

113 citations


Journal ArticleDOI
TL;DR: Patients with abetalipoproteinemia (ABL) who absorb tocopherol poorly and have extremely low levels of plasma and red blood cell toCopherol also had a low concentration of adipose tissue tocop herol, however, some ABL patients on massive supplementation with vitamin E did achieve normal concentrations of adiposes tissue to copherol.

91 citations


Journal ArticleDOI
TL;DR: In this paper, the UV absorbance, corrected fluorescence spectra, quantum yields and lifetimes of 4-bromomethyl-6,7-dimethoxycoumarin derivatives of carboxylic acids as well as of a few fatty esters are presented.

87 citations


Journal ArticleDOI
TL;DR: Apres separation par chromatographie d'echange d'ion, reaction avec le reactif du titre, les amino et iminoacides et les thiols sont doses par spectrometrie de fluorescence.
Abstract: Apres separation par chromatographie d'echange d'ion, reaction avec le reactif du titre, les amino et iminoacides et les thiols sont doses par spectrometrie de fluorescence. La methode est appliquee a l'analyse d'echantillons de sang depose sur disques de papier afin de determiner les erreurs de metabolisme a la naissance

82 citations


Journal ArticleDOI
TL;DR: The FPIA assay can measure as little as 0.6 mg/L of vancomycin and is free of interferences from hemolysis, lipemia, bilirubin, and changes in protein concentration.
Abstract: SummaryWe have extended fluorescence polarization immunoassay (FPIA) technology for the measurement of drugs to include the complex amphoteric glycopeptide antibiotic vancomycin (molecular weight, 1,449). Fluorescein-labeled vancomycin was employed as a tracer, and antisera specific for vancomycin w

Journal ArticleDOI
TL;DR: In this paper, metal-organic complexes were isolated from coastal seawater by adsorption onto octadecyl-bonded silica (SEP-PAK cartridges) and injected into a high-performance liquid chromatograph.

Journal ArticleDOI
TL;DR: It is found that modifications of the adenine moiety reduce nucleotide affinity for the enzyme, and was most pronounced with modifications at position 6 of the base.
Abstract: We determined the dissociation constant (Kd) of a series of nucleotides for the bovine skeletal muscle type II catalytic subunit by displacing lin-benzoadenosine 5'-diphosphate (lin-benzo-ADP) with increasing concentrations of competing nucleotide. The Kd of each nucleotide was calculated from the decreases in the fluorescence polarization of lin-benzo-ADP that accompany its displacement from the catalytic subunit. We found that modifications of the adenine moiety reduce nucleotide affinity for the enzyme. The effect was most pronounced with modifications at position 6 of the base. Replacement of the 3'-hydroxyl group of ribose with a hydrogen increased the affinity of the nucleotide; addition of phosphate to the 2'- or 3'-hydroxyl groups, on the other hand, decreased nucleotide affinity. MgATP and MgADP exhibited Kd's of about 10 microM. AMP, which contains a negatively charged alpha-phosphate, bound with reduced affinity (643 microM). Adenosine, which lacks a charged alpha-phosphate, bound with a higher affinity (32 microM). To learn more about the nature of the alpha-phosphate binding site, a series of uncharged and positively charged derivatives of the 5'-position on the ribose moiety was prepared. The uncharged derivatives bound with much greater affinity than the negatively charged AMP. The Kd's for 5'-tosyladenosine and 5'-iodo-5'-deoxyadenosine were 30 and 32 microM, respectively. Like the negatively charged AMP, positively charged derivatives also bound less tenaciously than the neutral species. The positively charged 5'-amino-5'deoxyadenosine, for example, exhibited a 15-fold higher Kd (506 microM) than the neutral congenors.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: Investigation of the influence of cholesterol on acyl chain dynamics in multilamellar vesicles of phosphatidylcholine found that increased cholesterol content had only slight effects on fluorescence lifetimes of the six probes and a single second-order equation described the relationship between r infinity and r for the five anthroyloxy fatty acid probes over a wide range of cholesterol content.

Journal ArticleDOI
TL;DR: 1-Hydroxypyrene is a major metabolite of pyrene given orally to pigs and a method for isolating the metabolite from urine is described, utilizing C18-adsorbent cartridges, h.p.l.c. separation, and fluorescence detection.
Abstract: 1-Hydroxypyrene is a major metabolite of pyrene given orally to pigs. A method for isolating the metabolite from urine is described, utilizing C18-adsorbent cartridges, h.p.l.c. separation, and fluorescence detection. Unconjugated 1-hydroxypyrene can be detected in the urine of pigs following oral administration of as little as 1 mg pyrene. Identity of the 1-hydroxypyrene was confirmed by u.v.-absorption and fluorescence spectrometry, mass spectrometry, and by comparison with the retention time characteristic of synthetic 1-hydroxypyrene.

Journal ArticleDOI
TL;DR: In this paper, the products of the reactions of electronically excited Ar(3P0, 3P2), Kr(3p2), and Xe(3 p2) atoms with the chloromethanes, chlorofluoromethane, CF3H, CF2HCl, CFHCl2, CFCl3Cl, and HCl have been investigated by dischargeflow technique, using atomic resonance fluorescence to probe dissociation channels.
Abstract: The products of the reactions of electronically excited Ar(3P0, 3P2), Kr(3P2), and Xe(3P2) atoms with the chloromethanes, chlorofluoromethanes, CF3H, CF2HCl, CFHCl2, CF2Cl⋅CF2Cl, CF3⋅CCl3, and HCl have been investigated by the discharge‐flow technique, using atomic resonance fluorescence to probe dissociation channels and emission spectroscopy. Energy transfer leading to cleavage of C–H or C–Cl bonds is extremely efficient, particularly in the reactions of Xe(3P2) with CF2Cl2 and CFCl3 and of Ar(3P0, 2) with CFCl3, in which more than two Cl atoms are released per primary reactive event. The observation of contrasting behavior in the reactions of Xe(3P2) with CF3H and CF4 has led to the discovery of a qualitative correlation between the rate constants, the products of the energy transfer process, and the accessibility of dissociative or ionizing states of the reagent molecule, as revealed by its vacuum UV absorption spectrum.

Journal ArticleDOI
TL;DR: The results indicate that the initial events in the fusion of LUV are in general, non-leaky, and the diversity of the relative kinetics of fusion and release in different phospholipid vesicle systems under various ionic conditions is emphasized.

Journal ArticleDOI
TL;DR: Mg2+ inhibited the Ca2+-induced fusion of PS vesicles, but did not cause any fusion by itself, consistent with previous results with the Tb/dipicolinic acid assay.

Journal ArticleDOI
TL;DR: The binding of gene 5 protein to various single-stranded polynucleotides is investigated by fluorescence titrations and stopped-flow measurements and model studies suggest that the preferential interaction with poly(dT) is not simply due to enhanced stacking interactions between the aromatic amino acids and the thymine residues.
Abstract: The binding of gene 5 protein to various single-stranded polynucleotides is investigated by fluorescence titrations and stopped-flow measurements. The association state of gene 5 protein itself is analyzed by equilibrium sedimentation: the monomer-dimer equilibrium found in the micromolar concentration range is described by a stability constant of 8 X 10(5) M-1. The fluorescence quenching upon binding to polynucleotides, studied over a broad concentration range and analyzed in terms of a cooperative excluded-site binding model, provides binding constants for "isolated" and for "cooperative" sites. The cooperativity for various ribo- and deoxyribopolymers is between 400 and 800 and is virtually independent of the ionic strength. The binding to isolated sites is strongly dependent upon the ionic strength; analysis in terms of polyelectrolyte theory indicates the compensation of 4 +/- 0.5 charges upon complex formation. The number of nucleotide residues covered by one protein molecule is also found to be 4 +/- 0.5 units. The affinity of gene 5 protein for polynucleotides increases in the series poly(C) less than poly(dA) less than poly(A) less than poly(U) much less than poly(dT); the binding constant for poly(dT) is roughly a factor of 1000 higher than that for the other polymers. Model studies with Lys-Tyr-Lys and Lys-Trp-Lys suggest that the preferential interaction with poly(dT) is not simply due to enhanced stacking interactions between the aromatic amino acids and the thymine residues. Stopped-flow reaction curves obtained by mixing of gene 5 protein with poly(dT) in the micromolar concentration range show three relaxation processes with time constants between 1 ms and 1 s.(ABSTRACT TRUNCATED AT 250 WORDS)

Journal ArticleDOI
TL;DR: In this article, a simple and reproducible method for the simultaneous determination of dialkyltin compounds and their possible metabolites was developed, which can be used to detect the presence of any number of possible metabolites.

Journal ArticleDOI
TL;DR: A convenient determination of pyrroloquinoline quinone (PQQ) in extracts of purified enzymes is possible with ion-pair chromatography on a HPLC reverse-phase column and with uv detection, but when culture supernatants have to be analyzed, a fluorescence detection system is more appropriate.

Journal ArticleDOI
TL;DR: The fluorescence intensity of diphenylhexatriene and of trimethylammonium-diphenyl hexatriene is measured when these probes are embedded in vesicles of dipalmitoyl- and dioleoylphosphatidylcholine and in mixtures of these vesicle as well as in vESicles of the mixed phospholipids.



Journal ArticleDOI
TL;DR: The weak temperature dependence of alpha implies that DNA torsional deformations do not occur primarily at sites of high enthalpy perturbed structures such as open base pairs.
Abstract: The torsion elastic constant alpha of linear phi 29 DNA has been determined as a function of temperature from 10 to 78 degrees C by studying the decay of the fluorescence polarization anisotropy (FPA) of intercalated ethidium dye. The time-dependent FPA was measured by using a picosecond dye laser for excitation and time-correlated single photon counting detection. Over the region 10-74 degrees C, alpha was effectively constant within experimental error, varying from (3.5 +/- 0.4) X 10(-12) dyn cm at 10 degrees C to (3.7 +/- 0.3) X 10(-12) dyn cm at 74 degrees C. At 78 degrees C, which is just above the melting temperature Tm = 76 degrees C, alpha decreased to (3.3 +/- 0.3) X 10(-12) dyn cm, and at 90 degrees C, where the DNA is completely denatured, both the fluorescence lifetime and the decay time of the FPA are characteristic of unbound ethidium bromide. The weak temperature dependence of alpha implies that DNA torsional deformations do not occur primarily at sites of high enthalpy perturbed structures such as open base pairs.

Journal ArticleDOI
TL;DR: On montre que le morin peut etre utilise comme reactif pour le dosage des composes organiques de l'etain les dialkyls+annanes, en particulier.
Abstract: On montre que le morin peut etre utilise comme reactif pour le dosage des composes organiques de l'etain les dialkyls+annanes, en particulier. La methode decrite est testee sur des tissus de rat

Journal ArticleDOI
TL;DR: The automated fluorescence polarization immunoassay system offers a rapid, efficient, and accurate method for monitoring vancomycin serum levels for both toxicity and efficacy.
Abstract: An automated fluorescence polarization immunoassay for the determination of vancomycin levels in serum was evaluated. The vancomycin assay is a homogeneous competitive inhibition immunoassay based on changes in fluorescence polarization that occur with antibody binding. This assay was compared with a liquid chromatographic assay and an agar well diffusion bioassay method by using clinical serum specimens and controls. Linear regression analysis of the data obtained on clinical specimens by the three methods resulted in correlation coefficients of 0.97 for the fluorescence polarization immunoassay versus the liquid chromatographic assay (n = 60), 0.90 for the fluorescence polarization immunoassay versus the bioassay (n = 57), and 0.90 for the liquid chromatographic assay versus the bioassay (n = 57). Repetitive analysis of control sera containing 7, 35, and 75 micrograms of vancomycin per ml by the fluorescence polarization immunoassay yielded coefficients of variation of 3.0, 1.7, and 2.3, respectively. No interference was demonstrated in spiked hemolytic, lipemic, or icteric sera, and the assay was free of matrix effects. The automated fluorescence polarization immunoassay system offers a rapid, efficient, and accurate method for monitoring vancomycin serum levels for both toxicity and efficacy.

Journal ArticleDOI
TL;DR: In this paper, a time-resolved fluorescence measurement system was developed for determination of polycyclic aromatic hydrocarbons in natural lake waters at ultratrace levels, where the Xe lamp of a conventional fluorometer was replaced with a N/sub 2/ laser-pumped dye laser as an excitation source.
Abstract: For determination of polycyclic aromatic hydrocarbons in natural lake waters at ultratrace levels, a time-resolved fluorescence measurement system was developed. By replacing the Xe lamp of a conventional fluorometer with a N/sub 2/ laser-pumped dye laser as an excitation source, the authors could improve the detection capability for polycyclic aromatic hydrocarbons by 1 to 2 orders of magnitude. The measurement system was used as a detector for high-performance liquid chromatography. A detection limit of 180 fg was achieved for benzo(a)pyrene. The measurement precision was 3.9%. The instrument was applied to measure polycyclic aromatic hydrocarbons in the water of Lake Mashu. After allowing for extraction efficiency, the authors obtained analytical results of 0.009 ng/L, 0.007 ng/L, and 0.014 ng/L for benzo(k)fluoranthene, benzo(a)pyrene, and benzo(ghi)perylene, respectively. 9 figures, 7 tables.

Journal ArticleDOI
01 Nov 1983
TL;DR: In this article, the laser-induced saturated fluorescence method was further developed with the aim of increasing the accuracy of radical concentration measurements in flames, and the absolute number densities for CH and OH in a low-pressure acetylene/oxygen flame were obtained from saturation curves based on a two-level rate equation model, whose validity was checked for the experimental conditions.
Abstract: The laser-induced saturated fluorescence method was further developed with the aim of increasing the accuracy of radical concentration measurements in flames. Absolute number densities for CH and OH in a low-pressure acetylene/oxygen flame were obtained from saturation curves based on a two-level rate equation model, whose validity was checked for the experimental conditions. From these saturation curves, approximate oscillator strengths could be deduced, which could serve as a cross-check for the evaluated number densities. Temperatures were determined from rotational spectra of the excited molecules. – For CH as well as for OH, the concentrations obtained with different excitation methods agree well with each other. They were compared with kinetic model calculations. For the extension of the saturated fluorescence method to higher pressures, a multi-level model is being developed.