bluuebunny/crossref_metadata_2025_split huggingface dataset:
The nootropic concept and its prospective implications
Authors: Giurgea Corneliu E. 
Published: May 2005

AbstractGiurgea, C.E.: The nootropic concept and its prospective implications. Drug. Dev. Res. 2:441–446, 1982.The nootropic concept emerged about 10 years ago essentially from the unusual pharmacology of piracetam, which later on was confirmed and extended to human pharmacoclinics and therapeutics. A nootropic drug is characterized by a direct functional activation of the higher integrative brain mechanisms that enhances cortical vigilance, a telencephalic functional selectivity, and a particular efficiency in restoring deficient higher nervous activity. In contradistinction to other psychotropic drugs, nootropics do not induce direct reticular, limbic, or other subcortical events. Little is known with regard to nootropic, neurochemical mechanisms of action except that they interact with factors that contribute to the neuronal membrane stability, and possibly with the brain 5‐HT. Main therapeutical indications seem to be in children with speech disorders, in the posttraumatic, and posthypoxic sequelae, in vertigo of central origin, and in geriatric, moderately impaired, possibly dysmnesic patients. Other drugs, such as pyritinol, meclofenoxate, and, to some extent, hydergine and vincamine, do show partially nootropic activities. The nootropic line of research is by now multifaceted to deepen the neurochemical and neurophysiologic comprehension of nootropics' mode of action; to make clearer their clinical differential profile; to enlarge the nootropic framework to some other existing drugs, clinically if not pharmacologically related to piracetam; and to find new, more potent, and possibly more selective nootropic agents. The general aim of nootropic research is to find new drugs capable of enhancing directly the efficiency of the cognitive, noetic activity of the brain, thus compensating various neuro‐psychologic deficits such as, but not exclusively, those related to aging.
The effects of oxiracetam (ISF 2522) in patients with organic brain syndrome (a double‐blind controlled study with piracetam)
Authors: Itil Turan M. , Menon Gopi N. , Bozak Mahir , Songar Ayhan 
Published: May 2005

AbstractItil, T.M., G.N. Menon, M. Bozak, and A. Songar: The effects of oxiracetam, (ISF 2522) in patients with organic brain syndrome (a double‐blind controlled study with piracetam). Drug Dev. Res. 2:447–461, 1982.In a double‐blind controlled trial, the clinical effects of oxiracetam, a new “nootropic” compound, were investigated in a group of 60 elderly patients with organic mental disorders (DSM‐III). The starting dose of both oxiracetam and the control drug, piracetam, was 400 mg. The dosage was increased by 400 mg at weekly intervals up to 2,400 mg daily (sixth week). During the following 6 weeks the administered dose was fixed at 2,400 mg daily. Most of the important target symptoms improved significantly over time, both subjectively (i.e., rating scales) and objectively (i.e., psychological tests), after administration of either oxiracetam or piracetam. In comparison to piracetam, oxiracetam exhibited more statistically significant improvement in the memory factor, whereas piracetam showed more improvement than oxiracetam in factors of paranoid ideation and agitation. Both drugs were tolerable and did not elicit any significant side effects. It was postulated that “nootropics” may represent a new group of CNS effective compounds, and thus be a “second generation” of psychotropics, which have more direct effects on the central target organs than are presently found in the “classical” psychotropics.
Chemistry and pharmacology of nootropics
Authors: Nicolaus Bruno J. R. 
Published: May 2005

AbstractNicolaus, B.J.R.: Chemistry and pharmacology of nootropics. Drug Dev. Res. 2: 463–474, 1982.The paper discusses the chemistry and pharmacology of the nootropics, reviewing the new chemical entities to recently emerge and in particular the five‐membered heterocyclic lactams belonging to the pyrrolidinone class, such as piracetam and oxiracetam. These gammalactams are related to the folded conformation of GABA, which seems to play a role in the uptake mechanisms—that is, in the transport of GABA across the membrances into differnt nervous tissue elements. The classification of nootropics is discussed, taking into consideration the six main criteria recently suggested, which are: no direct vasoactivity, no change in basic rhythm of EEG activity, blood brain barrier passage, positive metabolic activity in humans and animals, low incidence of side‐effects, and objective demonstration of clinivicacy. A critical analysis is made of the various pharmacological and biochemical models employed to screen the nootropics, including a new approach based on the impaired learning rate of spontaneously hypertensive rats with cerebrovascular lesions. The activity of the new GABA‐derivative nootropic called oxiracetam is also described and compared with the forerunner of the class, piracetam.
Electrophysiological profile of neurotropics (hydergine, piracetam, pyritinol) in organic brain disease in the aged
Authors: Zimmermann P. , Fünfgeld E. W. , Seidel R. , Nischwitz W. 
Published: May 2005

AbstractZimmermann, P., E.W. Füfgeld, R. Seidel, and W. Nischwitz: Electrophysiological profile of neurotropics (hydergine, piracetam, pyritionol) in organic brain disease in the aged. Drug Dev. Res. 2:481–488, 1982.The effects of neurotropics on brainstem and cortical neuronal activity were compared between three groups of patients suffering from chronic brain disease (arteriosclerotic or senile dementia). Hydergine (6–9 mg/day), piracetam (1,200 mg/day), or pyritinol (600 mg/day) were administered orally for 8wk. EEG power spectral analysis, visual evoked potentials (VEP) and bink reflexes were performed after an initial wash‐out period of 2 wk, 2 and 8 wk of neurotropic medication, and a final wash‐out period of 2 wk. EEG power spectra following hyderine show a significant decrease in slow alpha activity (7.5–10 Hz) and after pyritinol in the slow theta range (3–5 Hz) in the occipital region. In the piracetam group the power of the fast theta (5–7.5 Hz) and slow alpha activity decrease in the occipital region of the dominant hemisphere. Only during pyritinol medication do these signs of cerebral activation correlate with an increase in the amplitude of P350 of VEP and of the R2 component of the blink reflex.
The long‐term development of fighting in mice: Implications for future research
Authors: Morgret Morris K. 
Published: May 2005

AbstractMice were observed for a period of 37 weeks by a continuous monitoring procedure. The data are presented in weekly blocks and differences across time are noted. A definite increase in fighting was observed beginning at approximately 5 weeks and increasing to a peak at the 7th week, then declining to a low at 12 weeks. A later peak occurred around the 19th week. In overall amounts of aggression the females were low, male littermates (MLM) intermediate, and male nonlittermates (MNLM) were highest.
Behavioral effects of experimental maternal hyperphenylalaninemia
Authors: Schalock R. L. , Copenhaver J. H. 
Published: May 2005

AbstractBiochemical and behavioral effects of pre‐ and postpartum hyperphenylalaninemia were evaluated on 52 Sprague‐Dawley rats. Biochemical results indicated elevated plasma phenylalanine levels during both the prepartum (Gestation Days 15‐21 and postpartum Days 1‐60 of age) injection phases. Behaviors were evaluated beginning at 81 days of age. Compared to control or postpartum subjects, prepartum subjects demonstrated significant decrements on each of the following: initial DRL: 12 learning; fearfulness (inverse relationship); activity; exploration; and sociability. Compared to controls, postpartum subjects were significantly less active and less exploratory.
C‐Phosphoniophosphaalkenes as Precursors of 1σ4,3σ2‐Diphosphaallenes: Scope and Limitations
Authors: Martin David , Gornitzka Heinz , Baceiredo Antoine , Bertrand Guy 
Published: May 2005

AbstractThe study of a general synthetic route to 1σ4,3σ2‐diphosphaallenes involving the reaction of LiHMDS with C‐phosphoniophosphaalkenes is reported. The choice of the base is critical since the precursors are highly electrophilic species that react cleanly with methyl‐, butyl‐, mesityl‐, or tert‐butyllithium to afford C‐phosphanylphosphonium ylides. The role of the substituents at the σ4‐phosphorus centre has alsobeen studied. The resulting phosphaallenes react cleanly with a Lewis acid and undergo [3+2] cycloaddition withazides to afford a five‐membered heterocycle in a three‐step process. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis and Properties of the Geometrically Controlled Mixed‐Valence Tetrahedral RuII2RuIII2L6 Cluster
Authors: Cai Ping , Li Ming‐xue , Duan Chun‐ying , Lu Feng , Meng Qing‐jin 
Published: May 2005

AbstractThe reaction of Ru(DMSO)4Cl2 and N,N'‐bis[1‐(pyridin‐2‐yl)ethylidene]benzidine (L) in the presence of NaClO4 afforded the tetranuclear ruthenium compound, Ru4L6·10ClO4, by self‐assembly. Magnetic and electrochemical measurements clearly indicated the presence of both RuII and RuIII moieties within the tetrahedral ruthenium cluster. The Robin‐Day Class II mixed‐valence behavior was supported by the UV/Vis‐NIR spectra with the electronic coupling parameter Vab of 200 cm–1. It is demonstrated that the mixed‐valenceRuII2RuIII2L6 cation was stabilized by controlling the coordination geometries of the ruthenium ions between octahedral and trigonal prismatic to fit the supramolecular structure of the tetranuclear cluster. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Direct potentiometric membrane electrode measurements of heparin binding to macromolecules
Authors: Yun Jong Hoon , Ma Shu‐Ching , Fu Bin , Yang Victor C. , Meyerhoff Mark E. 
Published: May 2005

AbstractThe use of a newly developed heparin responsive polymeric membrane electrode for directly monitoring the binding of heparin to a variety of other biological macromolecules is examined. Potentiometric titrations of protamine, low‐density lipoprotein (LDL), polybrene, DNase enzyme, and polylysine with either porcine or beef lung heparin can be followed conveniently by the electrode at various solution pHs. Such titrations yield endpoints that are used to determine the stoichiometry for the interaction of the different heparins with these macromolecules. Based on prior heparin calibration curves, the titration data can be recast in Scatchard form to obtain binding constants for these solution‐phase heparin‐macromolecular reactions. The speed and simplicity of the proposed method make it an attractive alternative to classical solid‐phase binding methods or newer homogeneous fluorescent polarization schemes for studying the solution‐phase interaction of heparin with other macromolecules.
Electrochemical characterization of aminated PVC‐based ion‐selective membranes
Authors: Cosofret Vasile V. , Lindner Ernö , Buck Richard P. , Kusy Robert P. , Whitley John Q. 
Published: May 2005

AbstractThe potentiometric and impedance characteristics of a large number of pH sensitive, piperazine‐based aminated PVC membranes are summarized. The main goal of the work was to predict the differences between “good” and “bad” responsive potentiometric pH membranes with very similar overall nitrogen contents. The only conclusion gained previously from other methods was that the N content should be between 0.5 and 0.8% for Nernstian response. The detailed analysis of the data show that a given N content of the basic material is a necessary but not a sufficient requirement with respect of the quality of potentiometric response. Conditions for appropriate pH response of the membrane are formulated in terms of surface and bulk impedance characteristics. The ideal pH response of an optimized aminated PVC membrane, which corresponds to a minimum surface impedance, is presented. The primary importance of surface amines relative to bulk amines (the conformation and distribution of active sites) is proven in a simple experiment.
Potentiometric discrimination between planar and octahedral anionic metal cyano complexes by liquid membrane electrodes based on lipophilic macrocyclic dioxopolyamines
Authors: Naganawa Ryuichi , Radecka Hanna , Kataoka Masamitsu , Tohda Koji , Odashima Kazunori , Umezawa Yoshio , Kimura Eiichi , Koike Tohru 
Published: May 2005

AbstractA novel type of poly(vinyl chloride) matrix liquid membrane electrodes that are capable of discriminating between planar and octahedral anionic metal cyano complexes has been developed by exploiting as the sensory elements lipophilic derivatives of macrocyclic dioxopolyamines (13‐hexadecyl‐1,4,8,11‐tetraaza‐12,14‐dioxocyclotetradecane, 15‐hexadecyl‐1,4,7,10,13‐pentaaza‐14,16‐dioxocyclohexadecane). Potentiometric response behaviors of these electrodes for a series of anionic metal cyano complexes were compared with those of the electrodes based on the corresponding nondioxo macrocyclic pentaamine (15‐hexadecyl‐1,4,7,10,13‐pentaazacyclohexadecane) as well as a conventional anion exchanger (Capriquat®). The electrodes based on the dioxopolyamines displayed strong potentiometric responses at pH 4.0 to the metal cyano complexes having a planar structure ([Ni(CN)4]2−, [Pt(CN)4]2−). In contrast, the responses to the metal cyano complexes having an octahedral structure ([Fe(CN)6]3−, [Fe(CN)6]4−) were only negligible. On the other hand, for all of the guests tested, the electrodes based on the nondioxo macrocyclic pentaamine or the anion exchanger showed strong linear responses to both planar and octahedral complexes. These results represent a new mode of potentiometric discrimination displayed by dioxo‐type macrocyclic polyamines having both amine and amide moieties.
Urea biosensor based on amperometric ammonium ion electrode
Authors: Senda Mitsugi , Yamamoto Yukitaka 
Published: May 2005

AbstractAn amperometric urea biosensor is described: urease is immobilized on the amperometric ammonium ion electrode surface, and the ammonium ion produced by hydrolytic decomposition of urea by urease is determined by the pulse amperometric technique. Theoretical considerations on the steady‐state concentration distribution of the substrate (urea) and the product (sum of ammonia and ammonium ion) in the immobilized‐enzyme layer show that the concentration of the product at the ion‐selective electrode surface is proportional to the concentration of the substrate at the solution side surface of the immobilized‐enzyme layer up to a certain limiting concentration. The limiting concentration depends on the enzyme‐loading factor (Thiele modulus) as well as the Michaelis constant of the enzyme reaction. A practical urea sensor was constructed by immobilizing urease on an amperometric ammonia gas sensor. Preliminary experimental results and discussion are given. With the amperometric urea sensor, the correction for the residual ammonium ion in test solution can be easily achieved with an auxiliary, amperometric urease‐removed urea sensor.
Iodide‐selective electrodes based on a mercury‐triisobutylphosphine sulfide complex
Authors: Daunert Sylvia , Florido Antonio , Bricker Jordi , Dunaway Wes , Bachas Leonidas G. , Valiente Manuel 
Published: May 2005

AbstractIon‐selective electrodes (ISEs) were developed by impregnating plasticized poly(vinyl chloride) membranes with a complex of triisobutylphosphine sulfide and Hg2+. The electrodes were selective for halides and thiocyanate, iodide being the preferred anion. The overall selectivity pattern of the electrodes was I−> SCN− ≈︁ Br− > Cl− > No ≈︁ ClO > No ≈︁ SO. The electrodes were evaluated in both batch and flow‐injection modes.
Sequential flow‐injection potentiometric determination of iodide and iodine in povidone iodine pharmaceuticals
Authors: Hassan Saad S. M. , Marzouk Sayed A. M. 
Published: May 2005

AbstractA potentiometric sensor‐based flow‐injection system for determining iodide is described. The system utilizes a flow‐through sandwich cell and incorporates iron (II)‐tris bathophenanthroline iodide ion pair complex as an exchange site in a PVC matrix membrane. The sensor displays a fast response for 10−1 to 10−6 M iodide ion with an anionic slope of 59.1 ± 0.3 mV/concentration decade over the pH range 1 to 11. The experimental setup offers a precise, sensitive, selective and high sample throughput technique for determining iodide and iodine over a wide range of concentration. The limit of detection is 0.5 ppm iodide in a 20 μL sample. The average recovery is 99.8%, and the mean standard deviation is 0.5%. Sequential flow‐injection determination of iodide and iodine in some pharmaceutical preparations containing povidone iodine is performed by sample injection in a sodium sulfate‐ascorbic acid stream and monitoring of the total iodide equivalent to I− and I2. This is followed by injection of a second sample in an alkaline resorcinol stream and measuring of the iodide equivalent to I− and 1/2 I2. Iodine and iodide concentrations are calculated from the consecutive signals. The method gives results in good agreement with those obtained by the United States Pharmacopeia.
Electrochemical determination of iron in YBa2(Cu1–xFex)3O7 superconducting compounds
Authors: Boutakhrit Khalid , Kasmi Asma El , Kauffmann Jean‐Michel , Deltour Robert , Mehbod Mohamed , Marvin Craig A. 
Published: May 2005

AbstractThe electrochemical determination of iron in doped YBaCuO superconducting compounds has been investigated by differential pulse polarography (SMDE) and by differential pulse voltammetry using a glassy carbon electrode. A well‐defined peak for iron was observed at –0.15 V (vs. Ag‐AgCl) reference electrode in sodium citrate/EDTANa2H2 pH 6. The electrochemical results have been validated by spectroscopic procedures, including atomic absorption and energy dispersion X‐ray spectroscopy. The differential pulse polarography using the standard addition method for peak validation has been found to be most appropriate.
Comparison of dibenzo‐16‐crown‐5 compounds with pendent amide groups as sodium ionophores in ion‐selective electrodes and in solvent extraction
Authors: Ohki Akira , Iwaki Kaoru , Naka Kensuke , Maeda Shigeru , Collier James J. , Jang Youngchan , Hwang Hong‐Sik , Bartsch Richard A. 
Published: May 2005

AbstractPotentiometric selectivities for alkali metal, alkaline earth metal and ammonium ions for a series of N,N‐dialkylsym‐( R)dibenzo‐ 16‐crown‐5‐oxyacetamides in solvent polymeric membrane electrodes are determined. For N, N‐dipentyl sym‐(R)dibenzo‐ 16‐crown‐5‐oxyacetdamides, the Na+/K+selectivity increases with variation of the R group in the order: hydrogen « propyl (linear alkyl) < isopropyl, neopentyl (branched alkyl). Solvent extractions of sodium and potassium picrates from aqueous solutions into 1,2‐dichloroethane were also performed. Ratios of the extraction constants for Na+and K+(logK/K) are similar in magnitude and show the same trends for structural variation within the ionophore as do the potentiometric selectivities between Na+and K+(logK) in the polymeric membrane electrodes. From the picrate extraction results. it is deduced that the enhancement in potentiometric selectivity for Na+over K+when the R group is changed from hydrogen to propyl arises from increased binding of Na+and diminished complexation of K+. On the other hand, the enhanced potentiometric selectivity for Na+over K+when a linear alkyl R group is replaced by a branched alkyl group appears to result from decreased complexation of K+only.
Electrochemical transduction of interactions of atrazine with bilayer lipid membranes
Authors: Nikolelis Dimitrios P. , Andreou Vangelis G. 
Published: May 2005

AbstractThis work investigates the interactions of atrazine with bilayer lipid membranes (BLMs) that can be used for the direct electrochemical sensing of this herbicide. Egg phosphatidylcholine (PC) and dipalmitoylphosphatidic acid (DPPA) were used for the formation of solventless BLMs. The interactions of atrazine with these membranes were found to be electrochemically transduced by BLMs in the form of a transient current signal with a duration of seconds, which reproducibly appeared within 1 min after exposure of the membranes to atrazine. The sensitivity of the response was maximized by use of BLMs composed of 35% (w./w.) DPPA, and by alteration of the phase distribution within membranes by the introduction of calcium ions in bulk solution. The mechanism of signal generation was related to the adsorption of atrazine with a consequent rapid reorganization of the membrane electrostatics due to atrazine aggregation at the surface of BLMs. Hydrogen bonding between atrazine and the carbonyl group of the lipid was explored by addition of platelet‐activating factor (PAF; an ether analog of PC) in BLMs composed of PC. Differential scanning calorimetry of vesicles composed of 15% DPPA was used to study the aggregation of atrazine in membrane domains enriched in the charged lipid. The magnitude of the transient current signal was linearly related to the concentration of atrazine in bulk solution with sub‐micromolar detection limits. This electrochemical transduction of atrazine interactions with BLMs holds prospects for flow injection monitoring of triazine herbicides.
Electrogeneration of superoxide ion at mercury electrodes with a hydrophobic adsorption film in aqueous media
Authors: Matsumoto Futoshi , Tokuda Koichi , Ohsaka Takeo 
Published: May 2005

AbstractThe electrogeneration of superoxide ion (O) by the one‐electron reduction of O2in alkaline aqueous media has been examined using the hanging mercury drop electrode in the presence of several surfactants of the quinoline groups. Based on the superoxide dismutase (SOD)‐catalyzed disproportionation behavior of Oon the cyclic voltammograms, new surfactants, in the presence of which Owas actually electrogenerated, could be searched: 2‐, 4‐, 6‐, 7‐ and 8‐methylquinolines (3,4,5,6 and 7), and 2‐phenyl and 5,6‐benzoquinolines (8 and 9). It was found that the effectiveness for the electrogeneration of Olargely depends on the surfactant and decreases in the order of quinoline (l), isoquinoline (2) > 5, 6, 7 > 3, 4 > 8 > triphenylphosphine oxide (10) > 9. In addition, a brief discussion on the structure and physicochemical properties of the surfactant film desirable for the effective Oelectrogeneration in aqueous media is given.
The effect of the removal of trace impurities on the adsorption behavior of octanoic acid at mercury–solution and at air–solution interfaces
Authors: Avranas Antonis , Retter Utz , Lunkenheimer Klaus , Lohse Heinz 
Published: May 2005

AbstractIn this article we explore the kinetics of adsorption of octanoic acid at the mercury‐water interface using phase sensitive AC voltammetry. These measurements were performed before and after stepwise purification of the octanoic acid solution, in order to distinguish between the adsorption behavior of the octanoic acid and its impurities. The adsorption of both octanoic acid and the surface active impurities decrease the capacitance with time. Removing the latter during the purification procedure results in a faster achievement of the equilibrium state and in higher capacitance values. The adsorption was also studied at the air‐water interface using dynamic surface tension measurements. Comparable results are obtained for both interfaces.