A study of the postnatal change in trace element levels in rat tissues by thermal neutron activation analysis

In order to obtain information about postnatal changes in trace element levels in rat tissues, the age-dependent variations in the concentrations of 6 elements (Fe, Zn, Co, Se, Rb and Cs) were investigated by thermal neutron activation analysis. Several variation patterns were revealed in their concentrations as a function of postnatal age, depending on the combination of an element and an organ: (1) A steady state without significant variations (Zn and Se in brain, Rb and Cs in liver), (2) accumulation till a steady level is attained in time (Se in liver and kidney, Co in kidney), (3) depletion till a steady level is attained in time (Fe and Co in brain, Zn in liver and kidney, Rb and Cs in kidney), (4) permanent depletion (Rb and Cs in brain), and 95) initial drop followed by gradual increase in concentration levels (Fe in liver and kidney, Co in liver)     

Simultaneous liquid chromatographic determination of 39 polycyclic aromatic hydrocarbons in indoor and outdoor air and application to a survey on indoor air pollution in Fuji, Japan

An analytical method was established for the simultaneous determination of 39 polycyclic aromatic hydrocarbons (PAHs) in air. The method was applied to a survey of gaseous and particulate PAHs in household indoor air. The survey was performed in 21 houses in the summer of 1999 and in 20 houses in the winter of 1999-2000 in Fuji, Japan. Thirty-eight PAHs were determined in indoor and outdoor air in the summer, and 39 PAHs were determined in indoor and outdoor air in the winter. The concentrations of gaseous PAHs in indoor air tended to be higher than those in outdoor air in the summer and winter. The concentrations of particulate PAHs in indoor air were the same as or lower than those in outdoor air in the summer and winter. PAH profiles, correlations between PAH concentrations, and multiple regression analysis were used to determine the factors affecting the indoor PAH concentrations. These results showed that gaseous PAHs in indoor air were primarily from indoor emission sources, especially during the summer, and that indoor particulate PAH concentrations were significantly influenced by outdoor air pollution.     

延边地区65～108岁健康老人头发中锌、铜、铁、锰、镁的含量

用原子吸收光谱法测定延边地区317名65～108岁老人头发中锌、铜、铁、锰、镁含量，观察不同民族、性别、年龄老人这些元素的差异。结果表明：1.朝鲜旗发锌低于汉族，满族发铜低于汉族、朝鲜族，汉族发镁高于朝鲜族、满族，发铁、发锰在汉、朝、满民族之间无区别。2．汉族、朝鲜族男发锌高于女性，汉族女性发铜高于男性，发铁、发锰、发镁在性别之间无区别。3、90岁组朝鲜族发锰、发镁低于65岁、76岁组，朝鲜族发锌、发铜、发铁在65～108岁之间无统计学意义。     

Histological study of some Echium vulgare, Pulmonaria officinalis and Symphytum officinale populations

Plants living in different ecological habitats can show significant variability in their histological and phytochemical characters. The main histological features of various populations of three medicinal plants from the Boraginaceae family were studied. Stems, petioles and leaves were investigated by light microscopy in vertical and transverse sections. The outline of the epidermal cells, as well as the shape and cell number of trichomes was studied in leaf surface casts. Differences were measured among the populations of Echium vulgare in the width and height of epidermis cells in the stem, petiole and leaf, as well as in the size of palisade cells in the leaves. Among the populations of Pulmonaria officinalis significant differences were found in the length of trichomes and in the slightly or strongly wavy outline of epidermal radial cell walls. Populations of Symphytum officinale showed variance in the height of epidermal cells in leaves and stems, length of palisade cells and number of intercellular spaces in leaves, and the size of the central cavity in the stem. Boraginaceae bristles were found to be longer in plants in windy/shady habitats as opposed to sunny habitats, both in the leaves and stems ofP. officinalis and S. officinale, which might be connected to varying levels of exposure to wind. Longer epidermal cells were detected in the leaves and stems of both E. vulgare and S. officinale plants living in shady habitats, compared with shorter cells in sunny habitats. Leaf mesophyll cells were shorter in shady habitats as opposed to longer cells in sunny habitats, both in E. vulgare and S. officinale. This combination of histological characters may contribute to the plant's adaptation to various amounts of sunshine. The reported data prove the polymorphism of the studied taxa, as well as their ability to adapt to various ecological circumstances.     

Analytical strategies to determine antibiotic residues in fish

The accelerated growth of aquaculture has resulted in a series of harmful effects to human health. The widespread and unrestricted use of antibiotics in this industry, to prevent bacterial infections, leads to remaining amounts in the aquatic environment. This has resulted in the emergence of antibiotic-resistant bacteria in aquaculture environments, in the increase in antibiotic resistance in fish pathogens as well as in the transfer of these resistance determinants to human pathogens. Moreover, the use of large amounts of antibiotics may lead to the presence of residual antibiotics in fish tissue and fish products. Fluoroquinolones, tetracyclines, penicillins, sulphonamides and other antibiotics, exhibiting activity against both Gram-positive and Gram-negative bacteria, are widely used for the treatment and prevention of diseases in fish. An extended and comprehensive review on the recent analytical methodologies concerning antibiotic residues in fish reported in the literature is provided in the present article. Emphasis is given on sample preparation regarding isolation and purification, chromatographic conditions and method validation according to legislation. Results of published assays are comparatively presented and criticised.     

Calibration methods for microdialysis sampling in vivo: muscle and adipose tissue

Calibration methods for microdialysis sampling were studied in the muscle and adipose tissue of rats. Both the delivery method and the no-net-flux method were used to determine the extraction efficiency (EE) of acetaminophen and caffeine in both tissues. There was no concentration dependence of the EE either in vitro or in vivo for either acetaminophen or caffeine. The EEs determined by the delivery and no-net-flux methods were not different. However, the EEs of both caffeine and acetaminophen determined in vitro were significantly higher than those determined in the muscle and adipose. This indicates that mass transfer in the tissue is the rate-determining factor for the EE in vivo. The relative difference between the EE in vitro and the EE in the muscle was smaller than the difference between the EE in vitro and the EE in the adipose. In addition, the EE in the muscle decreased more than the EE in the adipose after the animal was euthanized. This indicated that exchange between the extracellular fluid and plasma is the rate-determining step in mass transport relative to microdialysis sampling. This has a more significant effect on the EE in the muscle than the EE in the adipose. Both the delivery and no-net-flux methods can be used to calibrate microdialysis probes in the muscle and adipose.     

Crystal structure transformations in ammonium and alkali metal perchlorates

A comparative study of the polymorphic transformations in ammonium and the alkali metal perchlorates has been made using differential thermal analysis. Certain correlations have been attempted between the observed trends in the transformation temperatures and available crystallographic and thermodynamic data. The transformation in the case of sodium perchlorate shows pronounced second-order effects. Considerable hysteresis is observed in the transformations in ammonium, potassium, rubidium and caesium perchlorates. Doping of ammonium perchlorate with ammonium phosphate is seen to result in an upward shift in the transformation temperature and an increase in the thermal hysteresis. Prior mechanical and thermal treatment is also seen to result in a broadening of the hysteresis loops in the case of ammonium and potassium perchlorates. The results are explained in terms of contrapolarization effects and the production of strain in the material as a result of prior treatment.     

Ultraviolet-B radiation causes an upregulation of survivin in human keratinocytes and mouse skin

Understanding of the mechanism of ultraviolet (UV)-mediated cutaneous damages is far from complete. The cancer-specific expression of Survivin, a member of the inhibitor of apoptosis family of proteins, coupled with its importance in inhibiting cell death and in regulating cell division, makes it a target for cancer treatment. This study was designed to investigate the modulation of Survivin during UV response, both in vitro and in vivo. We used UV-B-mediated damages in normal human epidermal keratinocytes (NHEK) cells as an in vitro model and SKH-1 hairless mouse model for the in vivo studies. For in vitro studies, NHEK were treated with UV-B and samples were processed at 5, 15, 30 min, 1, 3, 6, 12 and 24 h after treatment. Our data demonstrated that UV-B exposure (50 mJ/cm2) to NHEK resulted in a significant upregulation in Survivin messenger RNA (mRNA) and protein levels. We also observed that UV-B exposure to NHEK resulted in significant (1) decrease in Smac/DIABLO and (2) increase in p53. For in vivo studies, the SKH-1 hairless mice were subjected to a single exposure of UV-B (180 mJ/cm2), and samples were processed at 3, 6, 12 and 24 h after UV-B exposure. UV-B treatment resulted in a significant increase in protein or mRNA levels (or both) of Survivin, phospho-Survivin and p53 and a concomitant decrease in Smac/DIABLO in mouse skin. This study demonstrated, for the first time, the involvement of Survivin (and the associated events) in UV-B response in vitro and in vivo in experimental models regarded to have relevance to human situations.     

Expression patterns of betaig-h3 in chondrocyte differentiation during endochondral ossification

betaig-h3 is a TGF-beta-induced extracellular matrix protein which is expressed in many tissues including bones and cartilages. In previous reports, we showed that betaig-h3 mediates cell adhesion and migration and, especially in bones, negatively regulates the mineralization in the end stage of endochondral ossification. Here, to elucidate the expression pattern and role of betaig-h3 in chondrocyte differentiation, ATDC5 chondrocytes and embryonic and postnatal mice were used for in vitro differentiation studies and in vivo studies, respectively. betaig-h3 was strongly induced by the treatment of TGF-beta1 and the expression level of betaig-h3 mRNA and protein were highly expressed in the early stages of differentiation but decreased in the late stages in ATDC5. Furthermore, the patterns of TGF-beta1, -beta2, and -beta3 mRNA expression were concurrent with betaig-h3 in ATDC5. betaig-h3 was deeply stained in perichondrium (PC), periosteum (PO), and prehypertrophic chondrocytes (PH) through the entire period of endochondral ossification in mice. betaig-h3 was mainly expressed in PC and PH at embryonic days and obviously in PH in postnatal days. These results suggest that betaig-h3 may play a critical role as a regulator of chondrogenic differentiation in endochondral ossification.     

Variability of total flavonoid, polyphenol and tannin contents in some Lythrum salicaria populations

Lythrum salicaria L. can vary in some morphological and phytochemical features according to its habitat. The present study investigates and compares the total flavonoid, polyphenol and tannin composition of twelve populations of L. salicaria collected from different ecological habitats in south-west Hungary. We studied the plant heights and soil moistures of the habitats analyzing the potential correlation between the morphological and environmental factors and chemical compositions. Total flavonoid, polyphenol and tannin contents were determined according to the valid spectroscopic methods of the European Pharmacopoeia. Total flavonoid content was higher in the populations collected during the main blooming period in August than at the beginning of flowering in July. Higher values for total polyphenol and tannin were detected in flowering branch tips in August than in July, and higher ones in leaves and shoots in July than in August. The highest flavonoid content was measured in the leaves, followed by the flowering branches and shoots as opposed to the total polyphenol and tannin contents, which were higher in the flowering branch tips than in the other organs.     

Field studies on the photosynthesis of two desert Chilean plants: Prosopis chilensis and Prosopis tamarugo.

Photosynthetic parameters were investigated in relation to light intensity (PAR and UV-B) in two Chilean Prosopis sp., Prosopis chilensis and Prosopis tamarugo in their natural habitats. The objective of this work was to compare the photosynthetic responses and to determine the degree of adaptation of both species to visible- and UV-radiation stress. One of the study sites was Refresco in the Atacama Desert, where P. tamarugo is an endemic plant and P. chilensis was introduced, and the other was Peldehue in the valley of Central Chile where only P. chilensis is present. Due to latitude, light intensity (UV-B and PAR) is higher in Refresco than in Peldehue. The parameters investigated in both species were photosystem II fluorescence, CO(2) assimilation, stomatal conductance, photosynthetic pigment composition, flavonoid absorption patterns and composition of chlorophyll-protein complexes. Fluorescence studies, CO(2) assimilation and stomatal conductance studies demonstrated that photosynthetic activity is more efficient and stable throughout the day in P. tamarugo than in P. chilensis in Refresco. Chlorophyll-protein complexes also seemed to be more stable in P. tamarugo than in P. chilensis. Photosynthetic pigment analyses indicated possible photodamage in P. chilensis trees in Refresco, but not in Peldehue. Such photodamage was absent in P. tamarugo. There was a considerable change in the flavonoid pattern between noon and afternoon hours in both species at both study sites. The physiological implications of these changes indicate that P. tamarugo is more adapted to high solar radiation than P. chilensis.     

Vibronic interactions and possible electron pairing in the photoinduced excited electronic States in molecular systems: a theoretical study

Electron-phonon interactions in the photoinduced excited electronic states in molecular systems such as phenanthrene-edge-type hydrocarbons are discussed and compared with those in the monoanions and cations. The complete phase patterns difference between the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbitals (LUMO) (the atomic orbitals between two neighboring carbon atoms combined in phase (out of phase) in the HOMO are combined out of phase (in phase) in the LUMO) are the main reason that the C-C stretching modes around 1500 cm(-1) afford much larger electron-phonon coupling constants in the excited electronic states than in the charged electronic states. The frequencies of the vibrational modes that play an essential role in the electron-phonon interactions for the excited electronic states are similar to those for the monoanions and cations in phenanthrene-edge-type hydrocarbons. Possible electron pairing and Bose-Einstein condensation in the photoinduced excited electronic states as well as those in the monoanions and cations in molecular systems such as phenanthrene-edge-type hydrocarbons are also discussed.     

Weak-to-strong confinement transition of semi-flexible macromolecules in slit and in channel

We compare confinement of stiff macromolecule in channel and in slit. Whereas in the channel a distinct and established transition exists, we elucidate here an ongoing controversy reported from previous experiment and simulation on existence of such transition in the slit. Our extensive molecular simulations in both geometries show only a very weak conformational crossover between moderate and strong confinements in slit in the same range of confinements where the distinct transition in channel is observed. In contrast to situation in channels relatively stable hairpin-like structures are not indicated around this weak transition in the slit. Observed difference from the prediction on behavior in blob regime under moderate confinement is explained by a crossover between dimensionalities in the slit and the extent of ideal conformation statistics to which the stiffer chains are prone. The strong confinement regime of stiff chain in slit characterized here has not been interpreted yet and it differs from the respective saturation-like Odijk regime in the channel.     

Radiochemistry teaching and research activities in Brazil

Summary Much concern has been expressed lately about the decline of teaching and research activities in radiochemistry in many countries, as was discussed in an IAEA Technical Meeting in Antalya, Turkey, in 2002, and also at MTAA-11 in Guildford, UK. In the IAEA meeting, a survey was presented about the current situation in different regions of the world (Eastern Europe, East and West Asia, Africa, North America and Latin America) by experts of each region. In the case of Brazil, which has nuclear research reactors and also cyclotrons in operation, the teaching and research activities in radiochemistry are concentrated in the three main institutes of the Brazilian Nuclear Energy Commission, in the University of S?o Paulo and in other universities, in different regions of the country. In the present paper, a closer look is given to the radiochemistry teaching and research activities that are being conducted nowadays in Brazil, comprising: number of radiochemistry courses and students being formed, main research areas being conducted, as well as research and production of radioisotopes for nuclear medicine, using nuclear reactors and cyclotrons.     

Enantiomer ratio of MK-0767 in humans and nonclinical species

MK-0767, (+/-)-5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[(4-trifluoromethyl)phenyl]methyl]benzamide, is a thiazolidinedione-containing dual peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist that has been studied as a potential treatment for patients with type 2 diabetes. MK-0767 contains a chiral center at the C-5 position of the thiazolidinedione ring and was being developed as the racemate, due to the rapid interconversion of its enantiomers in biological samples. In the present work the in vitro and in vivo concentration ratios of the (+)-(R) to (-)-(S) enantiomers of MK-0767 were determined in plasma from humans (in vitro only) and nonclinical species used in the toxicological evaluation of rac-MK-0767, namely CD-1 mice, Sprague-Dawley rats, beagle dogs, New Zealand white rabbits, and rhesus monkeys. The R/S ratio was determined by chiral liquid chromatography/tandem mass spectrometry. Species differences were observed in the in vitro and in vivo enantiomeric ratios, as well as differences between in vitro and in vivo in some species. The in vitro R/S ratio was similar in dogs and humans (approximately 1.5-1.7). In rats and monkeys, the ratio was approximately unity, both in vitro and in vivo. In mice, the ratio was higher in vitro (approximately 1) than in vivo (approximately 0.6), while in rabbits it was higher in vivo (approximately 1) than in vitro (approximately 0.5). These results suggested that differential binding of the MK-0767 enantiomers to plasma and tissue proteins and other macromolecules may be affecting the R/S ratio both in vitro and in vivo, since in protein-free systems MK-0767 exists as the racemate.     

氨基苯磺酸和氨基萘磺酸在反相离子对色谱和离子色谱中分离行为的比较

本文考察了氨基苯磺酸和氨基萘磺酸染料中间体在反相离子对色谱和离子色谱中的分离行为，结果表明一些异构体在反相色谱中的保留顺序与离子色谱中的顺序发生颠倒。静电作用力在离子色谱中对保留值的贡献比在反相离子对色谱中对保留值的贡献要大，而疏水作用力在反相离子对色谱中对保留值的贡献却较在离子色谱中对保留值的贡献要大。离子对色谱更有利于有机离子的分离分析。     

Voltammetric determination of platinum in perfusate and blood: Preliminary data on pharmacokinetic study of arterial infusion with oxaliplatin

Because Platinum Group Elements have found widespread use in catalytic converters in cars and as chemotherapeutic agent, interest in the development of reliable analytical methods is carried out in order to monitor these analita in humans to protect the citizen's health.Considering that information on the levels of many trace elements in biological matrices is scarce and for many non-essential elements, baseline levels in the population, and especially in those particularly exposed to the risk are lacking, in this paper we optimize an analytical method for biological matrices, using a voltammetric technique to measure the concentration of Pt in blood and perfusate.The amount of Pt recovered from the blood and perfusate samples spiked with analita was observed to be meanly of 95% with 5–6% of R.S.D. These results indicated that proposed method for the determination of platinum in biological materials is accurate and reproducible.The amounts of platinum found in the blood samples of common ranged citizen were similar to quantification limit while in the patients the concentration ranged from 1.5 to 360 μg/L, in perfusate ranged from 0.7 to 9700 μg/l. The concentrations of Pt of populace and in patients before of infusion are in agreement with the level measured in the blood of unexposed patients.The proposed analytical method permits to determine the amount of Pt in the perfusate and subsequently absorbed by the target organs in order to determine the dose and timing of treatment and to avoid overdoses with related undesired effects.     

Riboflavin and UV-Light Based Pathogen Reduction: Extent and Consequence of DNA Damage at the Molecular Level

We are developing a technology based on the combined application of riboflavin (RB) and light for inactivating pathogens in blood products while retaining the biological functions of the treated cells and proteins. Virus and bacteria reduction measured by tissue culture infectivity or colony formation with UV light alone and in combination with RB yield equivalent results. The effects of RB as a sensitizing agent on DNA in white cells, bacteria and viruses in combination with UV light exposure have been evaluated. UV-mediated DNA degradation in Jurkat T cells and leukocytes in plasma as measured by the FlowTACS assay was significantly increased in the presence of RB. Agarose gel electrophoretic analysis of DNA in Escherichia coli and leukocytes in plasma demonstrated enhanced DNA degradation in the presence of RB. UV light in combination with RB prevented the reactivation of lambda phage compared with samples irradiated in the absence of RB. UV-mediated oxidative damage in calf thymus DNA was also enhanced in the presence of RB. These observations clearly demonstrate that the presence of RB and UV light selectively enhances damage to the guanine bases in DNA. These data also suggest that the type and extent of damage to DNA for virus in the presence of RB and light make it less likely to be repaired by normal repair pathways available in host cells.     

DFT calculations of the ionization potentials and electron affinities of serinamide

Adiabatic and vertical ionization potentials (IPs) and valence electron affinities (EAs) of serinamide in the gas phase have been determined using density functional theory (DFT) B3LYP, B3P86, and B3PW91 methods with the 6‐311++G** and 6‐311G** basis sets, respectively. IPs and EAs of serinamide in solution have been calculated with the B3LYP method using the 6‐311++G** and 6‐311G** basis sets. Eight possible conformers of serinamide and its charged states in the gas phase have been optimized employing the DFT B3LYP method with 6‐311++G** and 6‐311G** basis sets, respectively. All the adiabatic and vertical ionization potentials (AIPs and VIPs) of eight serinamide conformers in our work are positive values, whether in the gas phase or in solutions; the IPs in solutions are smaller than the results in the gas phase and decrease with increased dielectric constants in solutions. This finding indicates that the cationic states in solutions are more stable than those in the gas phase. All EAs of eight serinamide conformers are negative values in the gas phase, indicating that the anionic states are unstable with respect to electron autodetachment, both adiabatically and vertically. In contrast, all other adiabatic electron affinities (AEAs) are negative values in solutions except for 6S in water; 7S in chloroform, acetone, and water; and 8S in acetone and water, and increase with increasing of dielectric constants in solutions. All vertical electron affinities (VEAs) are negative values in solutions; however, no good rule has been found for these values in solutions. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006     

壳聚糖及其在分析化学中的应用

综述了壳聚糖、甲壳素在污水处理、电化学、原子吸收光谱、高效液相色谱、吸光光度法中的应用。引用文献28篇。