bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interpretation of inorganic arsenic metabolism in humans in the light of observations made in vitro and in vivo in the rat
Authors: Buchet J. P. , Lauwerys R. 
Published: January 2005

AbstractThe toxicity of inorganic trivalent arsenic for living organisms is reduced by in vivo methylation of the element. In man, this biotransformation leads to the synthesis of monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are efficiently eliminated in urine along with the unchanged form (Asi). In order to document the methylation process in humans, the kinetics of Asi, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of Asi. The arsenic methylation efficiency was also assessed in subjects acutely intoxicated with arsenic trioxide (As2O3) and in patients with liver diseases. Several observations in humans can be explained by the properties of the enzymic systems involved in the methylation process which we have characterized in vitro and in vivo in rats as follows: (1) production of Asi metabolites is catalyzed by an enzymic system whose activity is highest in liver cytosol; (2) different enzymic activities, using the same methyl group donor (S‐adenosylmethionine), lead to the production of mono‐ and di‐methylated derivatives which are excreted in urine as MMA and DMA; (3) dimethylating activity is highly sensitive to inhibition by excess of inorganic arsenic; (4) reduced glutathione concentration in liver moderates the arsenic methylation process through several mechanisms, e.g. stimulation of the first methylation reaction leading to MMA, facilitation of Asi uptake by hepatocytes, stimulation of the biliary excretion of the element, reduction of pentavalent forms before methylation, and protection of a reducing environment in the cells necessary to maintain the activity of the enzymic systems.
Degradation of a tetramethylarsonium salt by microorganisms occurring in sediments and suspended substances under both aerobic and anaerobic conditions
Authors: Hanaoka Keńichi , Araki Noriyuki , Tagawa Shoji , Kaise Toshikazu 
Published: January 2005

AbstractMicrobial degradation of a tetramethylarsonium salt during incubation at 25°C was investigated under both aerobic and anaerobic conditions. Two media (1/5 ZoBell 2216E and inorganic salt medium), added with the sediments or suspended substances as the sources of the microorganisms, were used. Degradation of the tetramethylarsonium salt occurred only in the ZoBell medium: under anaerobic conditions, trimethylarsine oxide and dimethylarsinic acid were derived with the sediments, and dimethylarsinic acid with the suspended substances, the salt degrading more rapidly with the former than with the latter. Small amounts of two metabolites, trimethylarsine oxide and inorganic arsenic(V), was also derived in the aerobically incubated ZoBell medium added with the suspended substances. This result means that the tetramethylarsonium salt is degraded to inorganic arsenic, which is the starting material for arsenic circulation in marine ecosystems, via trimethylarsine oxide and dimethylarsinic acid.
Detection of arsenobetaine in human blood
Authors: Shibata Yasuyuki , Yoshinaga Jun , Morita Masatoshi 
Published: January 2005

AbstractArsenobetaine was detected and quantified unambiguously in human plasma, serum and red blood cells by the combination of HPLC with ICP MS. Three different column conditions, i.e. two ionpair chromatographies for anionic (LC‐1) and cationic (LC‐2) compounds and gel‐permeation chromatography (LC‐3), were employed to confirm the assignment. Arsenobetaine was detected in every sample as a major component of the water‐soluble arsenic compounds, with an increasing concentration in plasma < serum < blood cell fractions. It was the sole detectable arsenic compound in LC‐1 and LC‐2, while a broad peak corresponding to high‐molecular‐weight compounds was identified in addition to arsenobetaine in LC‐3.
Critical review of analytical methods for determination of inorganic mercury and methylmercury compounds
Authors: Puk Richard , Weber James H. 
Published: January 2005

AbstractThis review describes determinations of mercury compounds under three categories: total mercury; separate determinations of inorganic mercury(II) and organomercury compounds by selective reduction; and speciation of inorganic mercury(II), monomethylmercury cation, and dimethylmercury. Topics described for each category include sample treatment, separation, detection, and limit of detection. Finally, we note that most methods would not detect dimethylmercury if it were present.
Catalysis of hydrosilylation: Part XXIV. H2PtCl6 in cyclohexanone as hydrosilylation catalyst—what is the active species in this catalytic system?
Authors: Guliński J. , Kłosin J. , Marciniec B. 
Published: January 2005

AbstractA cyclohexanone solution of H2PtCl6 was examined to find the catalytic species responsible for the hydrosilylation of the olefinic C=C bond. Similarly to other H2PtCl6–solvent systems (e.g. Speier's and Karstedt's catalysts), the real catalyst appeared to be colloidal platinum formed in situ by stepwise reduction [Pt(IV)→Pt(O)] and dechlorination of the platinum precursor. The role of cyclohexanone seems to be to form sufficiently stable platinum complexes to avoid rapid platinum precipitation and aggregation. The studies of H2PtCl6–solvent systems are of practical importance since these compounds are widely used catalyst precursors for hydrosilylation on an industrial scale.
Stereoselective reduction of α‐substituted β‐keto esters by hydrostannane/organotin triflate
Authors: Sato Tsuneo , Otera Junzo 
Published: January 2005

AbstractStereoselective reduction of α‐substituted β‐keto esters is achieved by the combined use of hydrostannane/organotin triflate. syn‐Aldols are obtained with more than 90% selectivities.
Validation of the analysis of organotin compounds in biological tissues using alkylation and gas chromatography
Authors: Stäb Joan A. , Th. Brinkman Udo A. , Cofino Wim P. 
Published: January 2005

AbstractSeveral critical steps in the analytical procedure for organotin compounds in the environment are identified in this paper and solutions are suggested. In particular, an improved procedure for quenching excess Grignard reagent is described. After insight into the nature of losses was obtained, the use of internal standards made it possible to reduce further the method variability. The systematic optimization of the analytical procedure resulted in a well investigated and robust method for analysis of organotin compounds in zebra mussel samples. Organotin compounds (OTs) which enter the environment as a result of their use as biocides and their degradation products are regularly found in environmental samples. Many different analytical techniques are currently being used,1 but little is known about their accuracy and precision.
Optimization of method for speciation of mercury(II), monomethylmercury cation, dimethylmercury and diethylmercury by hydride generation
Authors: Weber James H. , Puk Richard 
Published: January 2005

AbstractThis paper describes optimization details of an analytical method development of a hydride‐generation procedure for speciation of mercury(II), monomethylmercury cation, dimethylmercury, and diethylmercury using a heated quartz furnace with an atomic absorption spectrophotometer (AAS) as a detector. Typically a new analytical method is developed in steps such as the following: (1) determining analytes individually to confirm retention times and the lack of decomposition during the procedure; (2) comparing peak areas of all analytes as a function of quartz furnace temperature to optimize atomization for AAS detection; (3) conducting factorial experiments to determine which hydride‐generation reaction conditions are important in maximizing peak areas and which conditions interact with each other; (4) using the simplex optimization method to give final optimization of reaction conditions. These steps result in conditions that maximize optimized peak areas for analytes while minimizing experimental error.
The structure of very thin gold layers produced by metalorganic chemical vapour deposition
Authors: Allen D. W. , Haigh J. 
Published: January 2005

AbstractGold layers have been deposited from methyl(triethylphosphine)gold(I) by metalorganic chemical vapour deposition (MOCVD) and their structure and composition examined. At two deposition temperatures the layers have an underlying structure which is fine‐grained in the case of the 500°C layer and therefore of interest for thin‐layer device structures. Impurity levels are low in this layer.
Diorganotin(IV) and triorganotin(IV) derivatives of diphenic acid
Authors: Sandhu G. K. , Hundal R. 
Published: January 2005

AbstractThe diorganotin(IV) and triorganotin(IV) derivatives R2SnA (R = Me, n‐Pr, n‐Bu, n‐Oct) and (R3Sn)2A [R = Me, Ph, cyclohexyl (Cyh); A = an anion of diphenic acid] have been prepared and characterized by elemental analysis, IR, 1H and 13C NMR spectroscopies. Tetrahedral tin forms a part of a diphenate cyclic ring in the diorganotin complexes with unidentate carboxylates, which have further been used for the synthesis of cyclic acid anhydrides. The soluble dinuclear triorganotin complexes (Me, Ph) possess symmetrically bonded carboxylates while the less soluble compound (Cyh3Sn)2A has two asymmetrically bonded carboxylates. All have a trigonal bipyramidal structure with R3Sn units remote from each other.
Synthesis and characterization of phenoxarsin‐10‐yl 2‐R2N‐cyclopent‐1‐ene‐1‐carbodithioate (R = H, C2H5, cyclo‐C6H11CH2) and the crystal and molecular structure of the 2‐amino (R = H) derivative
Authors: Cea‐Olivares Raymundo , Toscano Rubén‐Alfredo , Estrada Mirna , Silvestru Cristian , García Patricia García y , López‐Cardoso Marcela , Blass‐Amador Georgina 
Published: January 2005

AbstractPhenoxarsin‐10‐yl derivatives of 2‐amino‐cyclopent‐1‐ene‐1‐carbodithioic acid, (ACDA), and its N‐alkyl derivativesO(C6H4)2 AsS2C—C5H6— NHR‐2 (R = H, CH2CH3, CH2C6H11,), have been prepared by reacting O(C6H4)2AsCI with the corresponding ACDA 1,1‐dithioic acid. The compounds were obtained by stirring stoichiometric amounts of the reagents in ethanol, over 24 h, at room temperature. The scale of the preparations were in the order of 2 mmol and the yields of the compounds ca 75%. The reactions were carried out in absolute ethanol. The compounds were characterized by IR, mass and NMR (1H, 13C) spectroscopy. The molecular structure of O(C6H4)2AsS2C—C5H6—NH2‐2 was determined using X‐ray diffractometry, achieving an R‐value of 6.3%; this compound is monomeric and contains an asymmetric monometallic biconnective 1,1‐dithiolato ligand [As—S(1) 2.272(2) å, As … S(2) 3.125(2) å]. An intramolecular hydrogen bond is established between one hydrogen atom of the NH2 group and the sulfur [S(2)] atom involved in the secondary interaction to arsenic. The dihedral angle (150.3(3)°) of the phenoxarsine moiety is practically unaffected by substitution of chlorine on arsenic by the carbodithioato ligand.
Synthesis of 1‐triphenylgermylpropiono‐4‐substituted semicarbazides, thiosemicarbazides and their heterocyclic derivatives
Authors: Ruyu Chen , Fengfu Li 
Published: January 2005

AbstractTwenty‐one new organogermanium compounds with the formulae Ph3GeCHR1CH2CONHNHC(X)NHR2 (1) (R1=H, Ph; = Ph, p‐CH3Ph, O‐CH3Ph, p‐ClPh, COPh, X = S, O) and magnified image (R1 = H, Ph; R2 = Ph, p‐CH3Ph, o‐CH3Ph, p‐ClPh; X=S, O) were synthesized and characterized by elemental analysis, 1H NMR, IR, MS and X‐ray diffraction techniques. Compounds l were prepared by the reactions of Ph3GeCHR1CH2CONHNH2 with R2NCX in chloroform in 77‐94% yields, and 2 were obtained by refluxing l with sodium hydroxide (8%) with yields of 55‐94%.
Developmental aspects of passive and active avoidance learning in rats
Authors: Riccio David C. , Rohrbaugh Michael , Hodges Louis A. 
Published: January 2005

AbstractIn Experiment 1, groups of rats 16, 19, 25, 32, and 90 to 120 days of age, were tested for retention of a passive avoidance response 2 min or 24 hr following a single training trial. Passive avoidance learning improved markedly with age, and retention over a 24‐hr interval was complete for all age groups. In Experiment 2, rats 19, 25, 32, and 90 to 120 days of age were trained in a simple, active avoidance task. A trials‐to‐criterion measure indicated that learning was relatively independent of age, although 19‐day rats were somewhat inferior to older rats. The occurrence of differences in passive avoidance learning through developmental ranges in age where simple active avoidance is little affected suggests that inhibition of responding may be selectively influenced by maturational variables.
Behavior of undisturbed 1‐ to 10‐day‐old chicks in different rearing conditions
Authors: Broom D. M. 
Published: January 2005

AbstractMost of 11 measures of the behavior of undisturbed chicks showed a gradual increase in frequency of ocurrence between the 1st or 2nd and the 10th day. A group of 4 measures, associated with feeding, showed a peak at 6 days among isolated birds. These changes are related to studies of food reserve utilization and improvement in motor ability during this period. Group‐reared birds showed patterns of behavior change with increasing age similar to isolated, but showed them earlier.Chicks were reared in conditions of different visual complexity and their behavior watched while they were undisturbed at 6 days. Where a moving object had been visible to the chicks during rearing, their behavior was much affected. Such birds spent much time as near to that object as a perspex partition would allow. If the object had been moving continuously, the birds were active for more of the observation period than were birds in grey‐walled pens, but conditions that were identical except for the lack of movement had no such effects on behavior.Behavior development is changed and perhaps accelerated by certain increases in the complexity of a chick's environment.
Effect of differential rearing on photic evoked potentials and brightness discrimination in the albino rat
Authors: Edwards H. P. , Barry W. F. , Wyspianski J. O. 
Published: January 2005

AbstractIn two related experiments, albino rats were split into enriched and impoverished groups at weaning, and were reared for two months in differential environments, one group in a large cage containing toys, the other in individual cages. Photic evoked potentials were obtained from all subjects both at weaning and after differential rearing, and mean group latencies were compared. At the end of the experimental period, all subjects were tested on a black‐white brightness discrimination. It was found that although the groups did not differ in evoked potential latency at weaning, after differential rearing there were significant latency differences. The enriched group developed shorter latencies than the impoverished group. At the end of the experiment, the enriched group obtained superior scores on a brightness discrimination test. It was concluded that differential rearing has measurable effects on certain aspects of the albino rat's behavior and physiology.
Behavioral effects of neonatal irradiation of the cerebellum. II. Quantitative studies in young‐adult and adult rats
Authors: Wallace Robert B. , Altman Joseph 
Published: January 2005

AbstractYoung‐adult and adult rats whose cerebellum was focally irradiated with a variable number of daily doses of 200 r X‐ray during infancy were tested for spontaneous locomotion, in activity wheels, for muscular strength, in a weight‐pulling apparatus, and, for skill in coordination, in a rope‐climbing apparatus. Spontaneous activity declined as a function of number of daily irradiations; the interaction of treatment, age, and prior experience was also investigated. Weight pulling capacity, as determined by running time in an alleyway, was not affected by irradiation with 1 to 4 × 200 r with loads equalling the rats' own body weights. Ease of rope climbing was inversely related to the number of daily irradiations in terms of climbing time, number of shocks received, falls off the rope, and other criteria.
Responsiveness to simple and complex auditory stimuli in the human newborn
Authors: Turkewitz Gerald , Birch Herbert G. , Cooper Kenneth K. 
Published: January 2005

AbstractThe relative effectiveness of complex and simple auditory signals was examined by presenting 2‐day‐old infants with a sequence of stimuli consisting of a white noise and a variety of pure tones (which ranged from 250 to 8000 Hz). “Catch” trials during which no stimulus was presented were interspersed throughout. The frequency of occurrence during “catch” trials of each of the response indicators (cardiac acceleration, toward‐turning eye movements, and finger movements) was used as the baseline. Although the white noise stimulus elicited significantly more responses on each of the measures than occurred during “catch” trials, none of the pure tones produced significant changes in baseline rates for any of the measures. Failure to obtain an effect on pure tone stimulation could have stemmed from an intensity effect. Therefore, an additional group of infants was examined using pure tones that ranged in intensity from 50 to 80 db (the intensity range covered by the relevant component frequencies in the white noise). None of these stimuli at any of the intensities used had an effect on any of the measures.
Behavior and brain growth in rats treated with p‐chlorophenylalanine in the first weeks of life
Authors: Hole Kjell 
Published: January 2005

AbstractIntraperitoneal injections of p‐chlorophenylalanine (pCPA) were given to 71 rats in the first 7 weeks of life, decreasing brain 5‐hydroxytryptamine concentrations to 20% of control values. The brain weight was significantly decreased, evident after 2 weeks of treatment, and also 52 days after the last injection. The retarded brain growth was not due to a general growth inhibition only: body weight was decreased initially, but from Day 24 the experimental animals gained weight more rapidly than the controls, resulting in a significantly higher body weight from Day 67.The decrease in brain growth was accompanied by behavioral changes, evident later in life. The first test was given 4 weeks after the last pCPA‐injection. The changes observed were moderate, but consistent in all the tests. There were no learning deficits or clear motivational changes. In all the tests there was evidence of a reduced arousal level in the pCPA‐treated rats: latencies were long, exploration was low, habituation to new environment was fast, and the reactivity was low.
Effect of protein‐calorie malnutrition on the development of social behavior in rats
Authors: Fraňková Slávka 
Published: January 2005

AbstractThe effect of early protein‐calorie malnutrition on the development of social behavior was studied during the first weeks of postnatal life. Activity and social interaction were recorded in groups of young rats either in the rearing cage or in a novel enviornment. The malnourished group had a delayed development of social behavior and smaller number of social contacts in all tests. During the suckling period, the nutritionally deprived pups were also more dependent on the mother, showed no social grooming, but were also more aggressive. On the 49th day, the normal rats showed increased exploration of the social stimulus whereas the malnourished rats were markedly inhibited. Apparently, early nutritional deficiency altered the social structure of the litter and of all individuals from the beginning by disturbing behavior and interactions of all members of the “family”.
Effects of artificial mothers and visual experience on adrenal responsiveness of infant monkeys
Authors: Hill Suzanne D. , McCormack Shirley A. , Mason William A. 
Published: January 2005

AbstractRhesus monkeys, maternally seprated at birth, were individually housed with a simple artificial mother in cages that were either completely enclosed (Enclosed Group) or had a clear plastic fron that faced the general nursery environment (Visual Group). Animals were removed from the living cage and placed for 1 hr in an enclosed carrying cage, either alone or with the artificial mother, following which blood samples were taken and analyzed for plasma cortisol levels. This procedure was repeated at monthly intervals during the first 7 months of life and at 9 and 12 months. In both groups plasma cortisol levels were higher when the animlas were alone than when the social surrogate was present. Rearing conditions were also effective, as reflected in longitudinal and diurnal contrasts between groups: cortisol levels were consistently high in the Visual Group from the 1st week of life, whereas the developmental pattern was curvilinear for the Enclosed Group. Significant diurnal variation in cortisol level was demonstrated only in the Visual Group.
Phrenoblysis: Special brain and mind growth periods. II. Human mental development
Authors: Epstein H. T. 
Published: January 2005

AbstractSpurts in the mental age of humans are shown to be recoverable from data giving the average mental age as a function of chronological age. Data from 13 independent studies are shown to give a highly consistent spectrum of ages at which spurts are found; these are 2‐4, 6‐8, 10‐12, and 14‐16, with an especially clear low rate of growth at 12‐14 yr. These ages correlate very well with those found for spurts in brain and skull sizes so that an obvious working hypothesis is that mutations for increased brain weight were selected for by virtue of the greater mental ability thus afforded to humans.
Vocal pathology in socially deprived monkeys
Authors: Newman John D. , Symmes David 
Published: January 2005

AbstractStructural abnormalities were found in the clear calls of rhesus monkeys raised in partial social isolation. These abnormalities included abrupt pitch changes, harmonic emphasis shifts, temporal discontinuity, and lack of the characteristic inflection found in such calls from mother‐reared control monkeys. Other forms of vocalization appeared structurally normal. Vocal pathologies were distinctive for each isolate tested and persisted over the age range 8‐24 months.
Individual differences in infant orienting and autonomic conditioning
Authors: Ingram Eben , Fitzgerald Hiram E. 
Published: January 2005

AbstractConditioned discrimination and discrimination reversal of the skin potential response was attempted and subsequently demonstrated in 3‐month‐old infants. Analysis of individual subject data indicated individual differences in conditionability, as well as a significant relation between orienting response magnitude and conditionability. In general, high‐magnitude orienters discriminated; low‐magnitude orienters did not. Behavioral ratings of state, sex of subject, and stimulus order were not related to orienting or to conditionability.
Age‐related differences in avoidance behavior in rats following CS preexposure
Authors: Wilson Linda M. , Phinney Richard L. , Brennan James F. 
Published: January 2005

AbstractWeanling and adult rats were exposed to either 0 or 10 conditioned stimulus (CS) presentations prior to 1‐way active‐avoidance (AA) training. Although CS exposure retarded avoidance acquisition in the adults, it produced no effect in the pups during avoidance learning. Neither adult nor young rats demonstrated preexposure effects in extinction. A general extinction analysis showed that pups had less resistance to extinction than the adults, despite a comparable avoidance learning criterion between age groups. The lack of preexposure influences on performance by the pups was compared to previous findings of response inhibitory deficits in immature rats. The results were considered in light of selective attention interpretations of latent inhibition.