showing 36 of ~574560 from 574555 documents
The N-terminal Amino Group of [Tyr8]Bradykinin Is Bound Adjacent to Analogous Amino Acids of the Human and Rat B2 Receptor
1996
To obtain data of the bradykinin B2 receptor's agonist binding site, we used a combined approach of affinity labeling and "immunoidentification" of receptor fragments generated by cyanogen bromide cleavage. Domain-specific antibodies to the various extracellular receptor domains were applied to detect receptor fragments with covalently attached [125I-Tyr8]bradykinin. As a cross-linker we used the homobifunctional reagent disuccinimidyl tartarate (DST), which reacts preferentially with primary amines. With this technique a [125I-Tyr8]bradykinin-labeled receptor fragment derived from the third extracellular domain was identified. The epsilon-amino group of lysine (Lys172) of the human B2 rece…
Spectroscopic Studies of Oligonucleotide Adducts and Base Sequence Preference of Adducts Formed by the Stereoisomers of 7,8-Dihydroxy-9,10-epoxy-7,8,…
1996
Abstract 5′-d(CCTATAGATATCC) has been reacted with BPDE and the adducts derived from binding of BPDE to the exocyclic amino group of deoxyguanosine (dG) were studied with spectroscopic methods. The major dG-adducts of (+)- and (-)-anti-BPDE and a minor adduct of (+)-syn-BPDE showed the characteristics of trans-adducts. The major products formed with (+)- and (-)-syn-BPDE exhibit cis-adduct characteristics. Annealing of BPDE-modified oligonucleotides to complementary or partially complementary strands results in reduced fluorescence intensity in several cases and in others the intensity is markedly increased. These differences demonstrate that the adduct microenvironment is strongly influenc…
Dysarthria and lacunar stroke
1996
We investigated the supranuclear tracts involved in speech production in 8 patients with dysarthria associated with a single lacunar stroke.Magnetic resonance imaging revealed the lesion site in 7 out of 8 patients. We tested corticobulbar tract function using transcranial magnetic stimulation and demonstrated impairment of the corticolingual projections in all the patients and in 5 patients impairment of the corticofacial projections. Sensory function in the oral cavity was impaired in 1 out of 8 patients.99m Tc hexamethyl-propylene amine oxime-single-photon emission computerized tomography (HMPAO-SPECT) imaging, performed in 5 patients, showed cerebellar diaschisis in 1, suggesting additi…
A star product on the spherical harmonics
1996
We explicitly define a star product on the spherical harmonics using the Moyal star product on ℝ6, and a polarization equation allowing its restriction on S2.
Synthetic Pathways for New Tubular Transition Metal Hydroxo- and Fluoro-Selenites: Crystal Structures ofM12(X)2(SeO3)8(OH)6(M=Co2+,Ni2+;X= OH−)
1996
The dumortierite-family structuresM12X2(SeO3)8(OH)6(M= Co2+and Ni2+;X= OH−and F−) have been synthesized. The crystal structures of the hydroxo-derivatives have been refined from X?ray powder diffraction data in the space groupP63mc(Z= 1) witha= 12.887(3) A andc= 4.981(4) A (M= Co2+,X= OH−or F−) anda= 12.704(5) A andc= 4.925(6) A (M= Ni2+,X= OH−or F−). Application of the Partial Charge Transference Model allows the understanding of the selenite derivatives crystal chemistry.
Metabolism of Phenanthrene, Benz[a]anthracene, Benzo[a]pyrene, Chrysene and Benzo[c]phenanthrene by Eight cDNA-expressed Human and Rat Cytochromes P4…
1996
Abstract Phenanthrene, benz[a]anthracene, chrysene, benzo[c]phenanthrene, and benzo[a]pyrene have been studied for their regiospecific oxidation by five human (1A1, 1A2, 2A6, 2E1, 3A4) and three rat (1A1, 1A2, 2B1) CYP isoforms. All substrates are preferentially metabolized by CYP1A1 and CYP1A2 in human and rat. Other isoforms play a minor role if at all. Significant differences between human and rat CYP isoforms can be recognized with regard to the regiospecific oxidation of PAH. For instance, K-region oxidation is more pronounced in rat than in human CYP1A1 and CYP1A2. Hence, extrapolation from metabolism studies in rodents to human may be limited.
Packings of an unidimensional regular pore structure as model packings in size-exclusion and inverse size-exclusion chromatography
1996
Using porous aluminas and aluminosilicates with a regular and well-defined pore structure an attempt was made to correlate the SEC data of polystyrenes with established theoretical models. The pore structure of the two types of packings was extensively characterized by means of transmission and scanning electron microscopy, nitrogen sorption and mercury porosimetry. The SEC distribution coefficients measured experimentally were correlated with the distribution coefficients calculated from the theoretical models for flexible polymers. A good correlation was observed for the packing of the simplest pore morphology, but remarkable deviations appeared for the materials with a more complex pore …
External Versus Internal Metabolic Activation of Polycyclic Aromatic Compounds in Mutagenicity Tests: A Comparison Using Heterologous Expression Syst…
1996
Abstract Benzo[a]pyrene-trans-7,8-dihydrodiol was virtually non-mutagenic to Chinese hamster V79p cells, but was strongly mutagenic to a V79-derived cell line expressing cytochrome P450 1A1, when the cells were exposed separately. In mixed cultures of these two cell types, it showed about 50 % of the mutagenic activity in V79p cells, compared to that observed in the enzyme-proficient cell line, indicating an efficient intercellular transfer of the active metabolite. The benzylic alcohols 1-hydroxymethylpyrene and 6-hydroxymethylbenzo[a]-pyrene were weakly mutagenic to Salmonella typhimurium TA1538 in the absence of a metabolic activation system, but were potent mutagens to a TA1538-derived …
DNA Polymerase Action on Oligonucleotide Templates from Human Ha-rasProtooncogene Containing N6-Deoxyadenosine Adducts Derived from Trans Addition of…
1996
Abstract In the present work we have used a DNA polymerase assay to investigate the primer extension with T7 DNA polymerase (Sequenase 2.0) and the Klenow fragment of Escherichia coli DNA polymerase I (exo − KF) on chemically synthesized 21mer templates representing partial sequences of the human Ha-ras protooncogene with site-specifically positioned trans-N 6-dA adducts of (-)- (adduct 1) and (+)-anti-benzo[c]phenanthrene 3,4-dihydrodiol 1,2-epoxides (adduct 2) at codon 61 (CA∗G; A∗ indicates the adducted position). With Sequenase 2.0 a complete block of primer extension opposite both adduct 1 and 2 was noted using a 10mer primer reaching the (n-1)-position of the adduct. A detailed analys…
Human corticotropin-releasing hormone and thyrotropin-releasing hormone modulate the hypercapnic ventilatory response in humans
1996
Human corticotropin-releasing hormone (hCRH) and thyrotropin-releasing hormone (TRH) are known to stimulate ventilation after i.v. administration in humans. In a placebo-controlled, single-blind study we aimed to clarify if both peptides act by altering central chemosensitivity. Two subsequent CO2-rebreathing tests were performed in healthy young volunteers. During the first test 0.9% NaCl was given i.v.; during the second test 200 micrograms of hCRH (n = 12) or 400 micrograms of TRH (n = 6) was administered i.v. Nine subjects received 0.9% NaCl i.v. during both rebreathing manoeuvres. The CO2-response curves for the two tests were compared within the same subject. In the hCRH group a marke…
The [Fe(etz)6](BF4)2 Spin-Crossover System - Part Two: Hysteresis in the LIESST Regime
1996
In the [Fe(etz)6](BF4)2 spincrossover system the iron(II) complexes occupy two nonequivalent lattice sites, sites A and B. Complexes on site A show a thermal high-spin (HS) low-spin (LS) transition at 105 K, whereas complexes on site B remain in the HS state down to 10 K. Complexes on both sites exhibit light-induced spin state conversions (LIESST) at 20 K: LS HS on site A with = 514.5 nm, and HS LS on site B with = 820 nm. The relaxation processes subsequent to the HS LS conversion on site B reveal a light-induced HSLS bistability for the complexes on site B at 70 K. The bistability as well as the absence of a thermal spin transition on site B are attributed to a thermal hysteresis for the…
Path integral Monte Carlo study of the internal quantum state dynamics of a generic model fluid
1996
We study the quantum dynamics of a generic model fluid with internal quantum states and classical translational degrees of freedom in two spatial dimensions. The path integral Monte Carlo data for the imaginary time correlation functions are presented and analyzed by the maximum entropy method. A comparison of the frequency distribution with those of a mean field approximation and virial expansion shows good agreement at high and low densities, respectively. \textcopyright{} 1996 The American Physical Society.
Synthesis and Characterization of a New Fully Aromatic LCP
1996
Abstract Liquid crystal polymers (LCP)are a relatively new class of polymers with very interesting and unusual properties. In particular, easy processability and outstanding mechanical and barrier properties make them very attractive. Unfortunately the high stiffness of their chains often leads to compounds having very high melting points and consequently to unprocessable materials. By adding a flexible segments in the chain backbone the LCPs become processable at lower temperatures but lower properties are displayed. A new rigid liquid crystalline polymer, having excellent physical properties, good processing temperature and a good cost/performance compromise, is described in this work. Th…
Protective effect of adenylate deaminase (from Penicillium lanoso-viride) against acute infections in mice
1996
We examined the effects of the immunomodulator-adenylate deaminase (E.C. 3.5.4.6) from Penicillium lanoso-viride on experimental mice infections. Prophylactic intraperitoneal administration of adenylate deaminase (ADA) increased survival time and numbers of survivors after infection with Salmonella typhimurium, Pseudomonas aeruginosa and influenza A (H3N2) virus. Protection against influenza virus after intranasal ADA application was also observed. The influence of ADA was time and dose dependent. The most pronounced protection was obtained by administration of 3 U ADA/mice 24 h prior to infection. ADA had no antibiotic effect against these bacterial strains. Protective effects of ADA were …
Effects on Arterial Blood Pressure of the Methanol and Dichloromethanol Extracts from Schinus molle L. in Rats
1996
The effects on arterial blood pressure of the methanol and dichloromethanol extracts from Schinus molle L. were analysed in urethane anaesthetized rats. In normotensive rats, the mean arterial blood pressure was significantly reduced by the i.v. administration of both extracts. The dichloromethanol extract inhibited the effects of noradrenaline on arterial blood pressure in the anaesthetized rat and it reduced the maximal contractile effect (Emax) induced by noradrenaline on rat vas deferens in the organ bath. However, the methanol extract did not modify the effects of noradrenaline in the evaluated tests.
The mystery of the Polish soul. B. W. Johnson's effectà rebours
1996
Studies conducted in Poland replicated a not very-well known effect discovered by B. W. Johnson (1937). In his study students estimated their mood on several successive days each time comparing it to the mood they usually have. The results revealed a peculiar positive bias in that the students usually defined their mood as 'better than usual'. Johnson's study was replicated in Poland, where demonstration of optimism is not a cultural norm. The results suggest that Polish subjects 'usually define their mood as worse than usual'. The generalization and limitation of this negative bias is discussed in the light of the Pollyanna Principle and related empirical studies involving Polish subjects.
Os, Sr, Nd, Pb, O isotope and trace element data from the Ferrar flood basalts, antarctica: evidence for an enriched subcontinental lithospheric sour…
1996
Os, Sr, Nd, Pb and O isotopes and trace element data are reported for basaltic andesite and andesite whole rocks and, in part, for selected mineral separates from the Jurassic Ferrar flood basalt province. Radiogenic Sr (> 0.709), unradiogenic Nd (εNd= −3 to −5), and radiogenic Pb isotopes, as well as low Nb/La ratios of 0.4 – 0.6 and Nb/La ratios between 0.45 and 0.6 are found for all rocks including our most primitive sample (Mg# = 71.9). This indicates involvement of either continental crust or enriched lithospheric mantle in magma genesis. 187Re/188Os correlates strongly with 187Os/188Os, with an age of 172 ± 5 Ma, in agreement with published Arsingle bondAr data. Initial 187Os/188Os of…
Influence of template basicity and hydrophobicity on the molecular recognition properties of molecularly imprinted polymers
1996
Abstract Triazine herbicides were used as model templates for a basic study of the molecular recognition process in imprinted polymers. Five structurally related triazine herbicides (atrazine, ametryn, cyanazine, prometryn and terbutylazine) that differ in basicity and hydrophobicity were imprinted. Chromatographic evaluation of the resulting materials in an aqueous-poor mobile phase showed that the selectivity for the template increased with its Bronsted basicity whereas it did not correlate with template hydrophobicity. Thus, the highest and lowest affinity and selectivity for the template was observed using the ametryn-imprinted (p K a =4.1) and the cyanazine-imprinted polymers (p K a =1…
Changes in the motility patterns of spermatozoa from the rabbit epididymis as assessed by computer-aided sperm motion analysis
1996
Sperm maturation in the epididymis includes changes in their potential for motility that enables spermatozoa to reach the egg and penetrate its investments. The motility characteristics of spermatozoa from the testis, the epididymis, and vas deferens of the rabbit were investigated by computer-assisted sperm analysis (CASA). Various forms of motility were displayed by sperm from different regions of the epididymis released into incubation medium. Testicular sperm were motile, although nonprogressive. The maximum percentage motility was expressed by sperm in the proximal cauda epididymidis, and forward progression was developed by spermatozoa from the distal caput. Once forward progression w…
On the Construction of Classes of Suffix Trees for Square Matrices: Algorithms and Applications
1996
AbstractWe provide a uniform framework for the study of index data structures for a two-dimensional matrixTEXT[1:n, 1:n] whose entries are drawn from an ordered alphabetΣ. An index forTEXTcan be informally seen as the two-dimensional analog of the suffix tree for a string. It allows on-line searches and statistics to be performed onTEXTby representing compactly theΘ(n3) square submatrices ofTEXTin optimalO(n2) space. We identify 4n−1families of indices forTEXT, each containing ∏ni=1(2i−1)! isomorphic data structures. We also develop techniques leading to a single algorithm that efficiently builds any index in any family inO(n2logn) time andO(n2) space. Such an algorithm improves in various …
Cocaine or phenylephrine/lignocaine for nasal fibreoptic intubation?
1996
In order to assess if a mixture of phenylephrine/lignocaine is as effective as cocaine for local analgesia and vasoconstriction during nasal fibreoptic intubation, 99 patients receiving topical nasal analgesia either with cocaine 10% or a mixture of phenylephrine 1% and lignocaine 4% were studied in a randomized double-blind investigation. After topical analgesia a flexible fibreoptic endoscope was advanced through a nostril. Larynx, glottis and trachea were endoscopically sprayed with lignocaine. Following induction of anaesthesia a nasotracheal tube was inserted fibreoptically. Pain intensity and amount of epistaxis during endoscopy were assessed. Blood pressure, heart rate and ECG-ST seg…
Distribución y formación de rentas en España
1996
n°6 de la collection "Documentos de Econometrica"; Documentos de Econometrica (Université de Saint Jacques de Compostelle), n°6; International audience
Clinical experience of a tricomponent acellular pertussis vaccine combined with diphtheria and tetanus toxoids for primary vaccination in 22,505 infa…
1996
Abstract OBJECTIVES: To assess the safety and tolerability of 12 lots of SmithKline Beecham Biologicals' diphtheria-tetanus-tricomponent acellular pertussis vaccine (DTaP) in a large cohort of 22,000 vaccinees, with detailed analyses of reactivity, immunogenicity, and immune response to pertussis toxin in subsets. METHODS: In a prospective, double-blind, multicenter trial in Germany, 22,505 healthy infants received three vaccinations of DTaP at age 3, 4, and 5 months. Serious adverse events were followed for 1 month after each vaccination, and neurologic events for 1 year or longer. Serum IgG antibodies were assayed before vaccination and 1 month after vaccination. RESULTS: After 67,000 dos…
On Transition Structures for Hydride Transfer Step in Enzyme Catalysis. A Comparative Study on Models of Glutathione Reductase Derived from Semiempir…
1996
As a model of the chemical reactions that take place in the active site of gluthatione reductase, the nature of the molecular mechanism for the hydride transfer step has been characterized by means of accurate quantum chemical characterizations of transition structures. The calculations have been carried out with analytical gradients at AM1 and PM3 semiempirical procedures, ab initio at HF level with 3-21G, 4-31G, 6-31G, and 6-31G basis sets and BP86 and BLYP as density functional methods. The results of this study suggest that the endo relative orientation on the substrate imposed by the active site is optimal in polarizing the C4-Ht bond and situating the system in the neighborhood of the…
Influence of micro-structure in the low temperature critical currents of YBa2Cu3O7?? thin films
1996
Epitaxial YBa2Cu3O7−δ films nucleate in c-axis oriented single-crystalline islands. The surface of the single-crystalline SrTiO3 substrates exhibit steps of one third of the YBa2Cu3O7−δ c-axis. These steps generate a mismatch in the island boundaries between the CuO2 superconducting blocks. We show that these defect regions are strong candidates for being the pinning centers responsible for the large critical currents observed in Laser Ablated and Sputtered thin films.
Bimodal Effect of Amphiphilic Biocide Concentrations on Fluidity of Lipid Membranes
1996
Abstract Using the spin label method (ESR) it has been shown that biologically active, amphiphilic compounds (quaternary ammonium salts -AS) containing polar heads with single and double positive charge caused, at low concentrations, decrease fluidity of liposome membranes formed with egg yolk lecithin (EYL). At higher concentrations an increase in fluidity was observed. With compounds having a single positive charge minimum fluidity of membrane structure occurs in the range of 1 to 3%, with compounds containing double positive charge -in the range of 4 -6 % . That effect does not depend on polar head size and length of alkyl chains of the AS used. Analysis of the electrostatic interaction …
Ventilatory responses to imagined exercise.
1996
We studied whether the ventilatory responses to imagined exercise are influenced by automatic processes. Twenty-nine athletes produced mental images of a sport event with successive focus on the environment, the preparation, and the exercise. Mean breathing frequency increased from 15 to 22 breaths/min. Five participants reported having voluntarily controlled breathing, two of them during preparation. Twenty participants reported that their breathing pattern changed during the experiment: 11 participants were unable to correctly report on the direction of changes in frequency, and 13 incorrectly reported changes in amplitude. This finding suggests that these changes were not voluntary in mo…
Clinical Recognition and Management of Adult Attention Deficit Hyperactivity Disorder
1996
Adults with attention deficit disorder (ADD) and attention deficit hyperactivity disorder (ADHD) are a new phenomenon to many health care providers. While increasing evidence indicates children with ADD/ADHD can have persistent problems into adulthood, the significance and management of these disorders for adults are poorly understood. Studies of adults are confounded by frequent comorbidity with other conditions and by retrospective diagnosis of childhood ADD/ADHD. Research studies of pharmacologic interventions do not indicate a clear pattern of efficacy and safety for any drug class. Pharmacologic treatment of adults with ADD/ADHD is often guided by clinical experience. Efficacy of treat…
Direct Analysis of Phase I Metabolites, Phenol Sulfates, Glucuronides and Glutathione Conjugates of Benzo[a]pyrene in Freshly Isolated, Hypothermical…
1996
Abstract The complex biotransformation of benzo[a]pyrene (BaP), the prototype of the class of carcinogenic polycyclic aromatic hydrocarbons, can be used as a tool to characterize the capacity of in vitro systems for the biotransformation of xenobiotics. In order to account for the ability of liver parenchymal cells to metabolize BaP, a method was developed for the isolation, separation and quantitation of its phase I metabolites, e.g. tetrahydrotetraols, trans-dihydrodiols, quinones and phenols, as well as its phase II metabolites, e.g. sulfates, glucuronides and glutathione conjugates, employing a combination of extractive and chromatographic steps. Upon incubation of BaP with freshly isol…
Preliminary Practical Findings on Drug Monitoring by a Transcutaneous Collection Device
1996
A noninvasive and nonocclusive skin patch (Sudormed™) was investigated for the systematic collection of drugs of abuse over a period of several days. First, the applicability and user friendliness were tested by volunteers. The permeability of the polyurethane dressing from the outside to the inside for an aqueous solution was shown by incubating the outside layer with Rhodamine B. No fluorescence could be detected in the cotton pad beneath. A single dose experiment using theophylline as a model compound showed that there was a delay in time before the substance could be determined in the pad. The drug content decreased with increasing time of patch application. When eight volunteers partic…
Notes on the Use of the Tables of Standard ISO 7730 for the Evaluation of the PMV Index
1996
Standard ISO 7730, which is also known as European Standard EN-ISO 7730, provides two alternative methods for the evaluation of the predicted mean vote (PMV) index: a calculation program and a set of tables. In order to use the tables, the operative temperature must be calculated beforehand. The impres sion is given from reading the standard that for a relative humidity of 50%, the two methods are equivalent, i.e. provide the same value for PMV, from the same initial values. In this paper, examples are given showing that the two methods are not equivalent. Differences between them are analysed and a proposal made to introduce an amendment in the next revision of the stan dard.
Detection of enteric adenoviruses 40 and 41 in stool specimens by monoclonal antibody-based enzyme immunoassays
1996
To examine the role of enteric adenoviruses (Ad40 and Ad41) in children with acute gastroenteritis, we evaluated 273 children with diarrhoea and 137 without enteric symptoms in Palermo, Italy, during an 8-month period. Stools were tested by two home-made monoclonal-based ELISAs to detected genus-specific adenovirus antigen and to type Ad40 and Ad41. Twenty-five samples (6.1%) were found to contain adenovirus, 18 of which were grown in Graham 293 and in HEp-2 cells. Ad40 and Ad41 were detected in 2.6% of children with diarrhoea and in none in the control group, while non-enteric adenoviruses were obtained from both patients (3.2%) and controls (6.5%). Samples containing Ad40 and Ad41 were po…
Electron spectroscopy using a multi-detector array
1996
A description is given of the novel electron spectrometer SACRED, which uses a multi-element Si array to detect cascades of conversion electrons. Its application to the study of deformed structures in 222Th is described.
Studies on the proton acceptor ability of phosphoryl compounds
1996
Abstract Dipole moments and molar Kerr constants of complexes of phenols with phosphoryl compounds were studied to establish the structure of complexes and parameters characterizing the proton acceptor ability of these compounds. The structures of these complexes and parameters ( μ H , Δ ( mk ) S , log K and δ 0 ) were established. It has been suggested that a new parameter Δ ( mK ) S — structural additive difference of the molar Kerr constant — makes it possible to determine changes of polarity and polarizability of the systems during complex formation.
Comparison of spin density calculation methods for various alkyl-substituted 9,10-anthraquinone anion radicals in the solution phase
1996
EPR and ENDOR spectra were recorded for 2-methyl-9,10-anthraquinone (2-methylAQ), 2-ethylAQ, 2-tertbutylAQ and 2,3-dimethylAQ anion radicals in the solution phase. The EPR spectra were simulated with the help of ENDOR data. The experimental isotropic hyperfine coupling constants (IHFCs) were compared with calculated values from semi-empirical INDO, spin-restricted AM1/CI and B3PW91 density-functional methods. The best computational methods for the IHFCs were the semi-empirical AM1/CI method and the B3PW91 density-functional method with a large basis set.
Sea Surface Temperature Fields Associated with West African Rainfall Anomaly Types
1996
Abstract Four West African rainfall anomaly types are defined in relation to the northern summer rainfall departure signs in the Sahel and in the Guinean region in order to investigate the statistical links between interannual variability of West African rainfall and sea surface temperature (SST) through the period 1950–90. Composite analysis depicts the setup of four different mean SST anomaly fields. Drought over all of West Africa is associated with the growth of positive SST anomalies in the eastern Pacific and in the Indian Ocean, and negative SST anomalies in the northern Atlantic and in the Gulf of Guinea. In contrast, drought limited to the Sahel corresponds mostly to a northward ex…