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PubMed2003

Quantifying histopathological alterations in the hepatopancreas of the woodlouse Porcellio laevis (Isopoda) as a biomarker of cadmium exposure.

The aims of this study were to determine and quantify the effects of cadmium sulfate on the histological structure of the hepatopancreas of Porcellio laevis, to determine the extent of the changes due to cadmium exposure, and to assess whether these effects could serve as biomarkers of cadmium exposure. For this purpose, different batches of P. laevis were exposed for 6 weeks to shredded leaves contaminated with a range of different concentrations of cadmium sulfate. Histological sections of different parts of the hepatopancreases revealed that the exposure changed the structure of the hepatopancreas. Quantification of this change in hepatopancreas structure (expressed as the percentage cellular area or PCA) showed that there was a dose-related change in certain areas of the hepatopancreas of woodlice exposed to cadmium sulfate in comparison to those areas of unexposed controls. This change was evident despite the fact that PCA also varied over the length of the hepatopancreas in the control specimens. This study showed that PCA can be a useful measure of change in the hepatopancreas resulting from toxic stress. Although it may not be practical for regular monitoring, it could serve as a useful research tool and general biomarker in studies of toxic stress in woodlice.

Animals↗
PubMed2001

Enzymatic oxidation of cadmium and lead metals photodeposited on cadmium sulfide.

Cadmium and lead metals deposited on CdS particles are shown to act as substrates--electron donors for enzymes, hydrogenase from Thiocapsa roseopersicina (HG), NAD-dependent hydrogenase from Alcaligenes eutrophus (NLH), and ferredoxin:NADP oxidoreductase (FNR) from Chlorella in the formation of hydrogen, NADH and NADPH, respectively. Adsorption of the enzyme on the surface of the metallized CdS particle is required for enzymatic oxidation of metal. The maximum rates for the formation of hydrogen and NADH catalyzed by hydrogenase and NAD-dependent hydrogenase with metals as electron donors are comparable with the rates obtained for these enzymes using soluble substrates. Kinetic analysis of the enzymatic oxidation of cadmium metal has revealed that the rate decreases mainly due to the formation of a solid product, which is supposed to be Cd(OH)2. The deceleration of lead oxidation catalyzed by hydrogenase proceeds at the expense of the inhibitory effect of the formed Pb2+. The enzymatic oxidation of electrochemically prepared cadmium metal is also shown. Based on these results, a new mechanism of action of the enzymes involved in anaerobic biocorrosion is proposed. By this mechanism, the enzyme accelerates the process of metal dissolution through a mediatorless catalysis of the reduction of the enzyme substrate.

Algal Proteins↗
PubMed1998

Protein phosphorylation in alveolar macrophages after stimulation with heavy metal-coated silica particles.

The aim of our study was to determine agonist- and time-dependent phosphorylation of distinct proteins in bovine alveolar macrophages after activation with quartz dusts and heavy metal-coated silica particles. Silica particles were coated with vanadium oxide or cadmium oxide. Separation of proteins was achieved by one-dimensional and optimized horizontal two-dimensional polyacrylamide gel electrophoresis. Protein phosphorylation was either determined by [32P] labeling and subsequent autoradiography or Western blotting using monoclonal antibodies against phosphotyrosine. One of the phosphorylated proteins was identified as the heat shock protein HSP-27. Stimulation with cadmium oxide-coated silica particles and PMA led to a significant increase of phosphorylated HSP-27. Additionally cadmium oxide-coated silica particles induced tyrosine phosphorylation of six main proteins. Stimulation with vanadium oxide-coated silica particles drastically increased the amount of tyrosine phosphorylated proteins while this effect was not observed with uncoated silica particles.

Animals↗
PubMed2002

AAS and AES determination of furaltadone, methadone and trazodone in pharmaceutical formulations.

Ion-associate complexes of furaltadone, methadone and trazodone hydrochlorides with [Cd(SCN)(4)](2-) and [Zn(SCN)(4)](2-) were precipitated and the excess unreacted cadmium or zinc complex was determined. A new method using atomic emission and atomic absorption spectrometry for the determination of the above drugs in pure solutions and in pharmaceutical preparations is given. The drugs can be determined by the affort method in the ranges 7.2-72.16, 6.9-69.18 and 8.1-81.6 microg/ml solutions of the three drugs, respectively.

Anti-Infective Agents, Urinary↗
PubMed2004

The impairments of neoblast division in regenerating planarian Polycelis felina (Daly.) caused by in vitro treatment with cadmium sulfate.

The effects of cadmium sulfate on the neoblast mitotic activity in regenerating planarian Polycelis felina (Daly.) were investigated. Mitotic abnormalities and chromosomal aberrations were evaluated after 6-h treatment and 24-h recovery period. The blastema were fixed, and examined cytologically through routine lactoorceine squash preparations. Mitotic indices were also determined. Cadmium sulfate induced a dose-dependent decrease in neoblast mitotic activity, accompanied with disturbances in distribution of cells over mitotic phases. Different cytological abnormalities with varying frequency were observed. Marked mitotic depression was concentration-dependent. Toxic effects of cadmium in regenerating planarian were mainly associated with mitotic spindle disturbances. Immediately after treatment mitotic abnormalities were prevalent over chromosomal and C-mitosis was the most prominent one. After 24-h recovery period a prevalence of mitotic over chromosomal aberrations was still present in animals treated with two higher concentrations of cadmium sulfate. However, the proportions of cells with chromosome stickiness in all treated animals were significantly increased compared to their post-treatment values. Observed mitotic impairments could be related to mitotic arrest contributing to retardations and delays, especially in animals treated with the highest concentration tested. The results obtained indicated usefulness of short term invertebrate assays as an alternative to in vitro pre-screening of toxic chemicals.

Animals↗
PubMed2000

Analogous features of delayed luminescence from Acetabularia acetabulum and some solid state systems.

This paper compares some features of the delayed luminescence in the seconds range emitted from an unicellular alga Acetabularia acetabulum and from some solid state systems. Results lead us to think that such delayed luminescence is connected to the dimension of the ordered structures present in both biological and solid state systems. In particular, for the biological system examined, these structures are thought to be those which contribute to the dynamic formation of the cytoskeleton.

Acetabularia↗
PubMed1998

A selective Pt-CdS photodiode to monitor erythemal flux.

The design and potential benefit of a solar ultraviolet (UV) radiometer reporting a maximum instantaneous flux of erythemally weighted heterogeneous energy is considered. The proposed device is electronically peak detecting; the user would ideally 'point and paint' the sun to find a localized maximum. A projected exposure time can be calculated from an instantaneous reading of erythemally weighted flux for a given minimal erythemal dose (MED) specified by the user. This calculation, though not necessarily providing a true exposure time, may be useful and informative in that it serves as a more 'recognizable' measure of erythemal flux and introduces a custom scale for each individual via their MED. Erythemal flux is calculated as the weighted integral sum [symbol: see text]j(lambda,t) epsilon(lambda) d lambda, where j (lambda, t) is the instantaneous angular integrated spectral irradiance accepted by human skin. This instrument proposal uses a single interference filter over a Pt-CdS photodiode; the interference filter is offered as a nominal design transmittance. The simulated response of the selective photodiode has a near-linear relation to the effective irradiance. Test inputs for evaluation purposes and to elucidate a transducer response are constructed from a spline interpolation of the World Radiation Center (WRC) spectrum and classic transmittance models. Our desired erythemal flux is offered in interconvertible UV Indexes (UVIs) as a function of zenith angle and atmosphere, characterized by elevation, ozone path, and turbidity.

Cadmium Compounds↗
PubMed2002

Formation of vesicle-templated CdSe hollow spheres in an ultrasound-induced anionic surfactant solution.

Hollow sphere of CdSe with size of approximately 100-200 nm can be templated from anionic surfactant sodium dodecyl sulfate (SDS) vesicles induced by the ultrasonic irradiation. The successful vesicle templating indicated that the outer leaflet of the bilayer is the receptive surface in the controlled growth of CdSe nanoparticles, which provide the unique reactor for the nucleation and mineralization growth of CdSe nanoparticles. The products were characterized by XRD, TEM, and HRTEM techniques. UV-vis spectrum recorded the optical properties of CdSe hollow spheres (2.01 eV), which showed an obvious blue shift relative to the bulk cubic CdSe (1.73 eV). Surfactant molecules (SDS) passivated in the CdSe hollow spheres were completely extracted, as determined by thermal gravimetric analysis (TGA). Systematic studies found that the ultrasound irradiation and concentration of surfactant (SDS) in the system were important factors on the controlled synthesis desired hollow sphere morphologies, and also the temperance have an importance influence on the mineralization and crystallization of the CdSe hollow spheres. Based on the observation on morphological difference of CdSe in different systems, the possible mechanism for the formation of CdSe hollow spheres was discussed.

Cadmium Compounds↗
PubMed1997

Persistence of cadmium-induced adaptive response to genotoxicity of maleic hydrazide and methyl mercuric chloride in root meristem cells of Allium cepa L.: differential inhibition by cycloheximide and buthionine sulfoximine.

With an objective to determine the period of persistence of the metal-induced adaptive response to chemical mutagens and heavy metals, growing root meristems of Allium cepa were conditioned by cadmium sulfate (CdSO4), 4 x 10(-7) and 4 x 10(-6) M for 1 h and subsequently challenged by maleic hydrazide (MH), 5 x 10(-3) M or methyl mercuric chloride (MMCl), 1.26 x 10(-6) M for 3 h at different time intervals ranging from a few minutes to several hours following the conditioning dose. Root meristems, fixed at regular intervals during recovery from 6 to 48 h, were cytologically analysed for cells with micronuclei (MNC). The adaptive responses to MH and MMCl were observed as early as 5 min after the Cd-conditioning that persisted for at least 48 h. Metabolic inhibitors, cycloheximide (CH). 10(-7) M and buthionine sulfoximine (BSO), 10(-4) M administered either prior to or simultaneous with Cd-conditioning effectively prevented the adaptive response to MH. Whereas BSO, an inhibitor of phytochelatin synthesis, prevented the adaptive responses from 15 min to 8 h after the conditioning dose, CH an inhibitor of cytoplasmic protein synthesis prevented the same from 6 to 48 h. The findings underscored the differential roles of phytochelatins and proteins underlying the foregone metallo-adaptive response.

Acclimatization↗
PubMed2002

Studies of electron paramagnetic resonance parameters and defect structures for Ti2+ and V3+ ions in CdS crystals.

By applying the high-order perturbation formulas based on the cluster approach for the EPR parameters of 3d2 ions in trigonal symmetry, the zero-field splitting D, g factors gparallel, gperpendicular, and hyperfine structure constants Aparallel, Aperpendicular for Ti2+ and V3+ ions in CdS crystals are studied. From the studies, the defect structures of these paramagnetic impurity centers are obtained and the EPR parameters are also explained reasonably.

Biophysical Phenomena↗
PubMed2002

Local tilting angles tau for Fe+ in Cd2+ site and Fe3+ in Si4+ site of CdSiP2 semiconductor.

The EPR parameters (g factors, g(parallel), g(perdendicular) and zero-field splitting D) for Fe+ in Cd2+ site and Fe3+ in Si4+ site of CdSiP2 semiconductor are calculated from the distinct high-order perturbation formulas. From the calculations, the local tetragonal distortions and hence the local tilting angles tau (which are different from the corresponding host values) for both paramagnetic centers are estimated. The results are discussed.

Cadmium↗
PubMed2002

Fourier-transform infrared and Raman spectra, and ab initio calculations for cadmium-n-di-iso-propylphosphorylguanidine-di-chloride (CdDPGCl2) complex.

Cadmium-n-di-isopropylphosphorylguanidine-di-chloride (CdDPGCl2) was synthesized in the solid phase and characterized previously. The Fourier transform infrared and Raman spectra of (CdDPGCl2) in the solid state were recorded and analyzed. Emphasis was placed on the vibrational assignment of the [(O2P=O-[CdCl2]-HN=C) fragment of the complete molecular structure. With the aim of assisting the vibrational assignment of the experimental spectra, a comparison with the spectra of N-di-isopropylphosphorylguanidine ligand was carried out and ab initio calculations have been performed with several effective core potentials and valence basis sets (Hay-Wadt (HW) and Stevens-Basch-Krauss (SBK)). Due to our limited computational resources, hydrogen atoms replaced the isopropyl groups. The calculated geometrical parameters showed excellent agreement with the experimental, as well as the RHF/MP2 calculated infrared wave numbers, when compared to the IR/Raman experimental wave numbers.

Cadmium Compounds↗
PubMed2003

Thermal studies and vibrational analyses of m-methylaniline complexes of Zn(II), Cd(II) and Hg(II) bromides.

The complexes having the MBr(2)L(2) (M: Zn, Cd and Hg; L: m-methylaniline) formulae have been prepared and characterized by their elemental analyses, thermogravimetric analyses, IR and Raman spectral studies. IR and Raman bands of the complexes have been assigned as compared with the free ligand. Coordination effects on the internal modes of m-methylaniline have been discussed. Vibrational spectra propose that the [ZnBr(2)(mMA)(2)] complex is in a tetrahedral environment around Zn(II) ion with C(2v) symmetry whereas Cd(II) and Hg(II) complexes have 5-coordinate polymeric bromide bridged structures.

Aniline Compounds↗
PubMed2004

Theoretical studies on vibrational spectra of some halides of Group IIB elements.

The vibrational spectra of Group IIB elements halides MX2 and their dimers M2X4 (M=Zn(II), Cd(II) and Hg(II); X=F, Cl, Br and I) have been systematically investigated by ab initio RHF and B3LYP methods with LanL2MB, LanL2DZ and SDD basis sets. The optimized geometries, calculated vibrational frequencies are evaluated via comparison with the experimental data. The vibrational frequencies, calculated by these methods with different basis sets, are compared to each other too. The best results can be obtained by RHF/SDD method, with this method, the deviations for MX2 and Hg2X4 are <7%. Some vibrational frequencies of M2X4 that have not been experimentally reported are also predicted.

Cadmium Compounds↗
PubMed2005

Characterization of nanocrystalline CdSe by size exclusion chromatography.

High-performance size exclusion chromatography (HPSEC) is a powerful tool for probing the size and size distribution of complex materials. Here we report its application to the analysis of cadmium selenide nanocrystals produced in organic solvents. If nanocrystal-column interactions are minimized, this method provides an accurate measure of nanocrystal hydrodynamic diameter directly in solution; such information is complementary to TEM in that it can measure the thickness of various capping agents. While the resolution of single-pass HPSEC is limited to 1 nm, we show here that recycling size exclusion chromatography can be applied to assess the fine details of a sample's distribution. Finally, semiconductor nanocrystals can be made a variety of shapes whose optical characteristics are difficult to distinguish. HPSEC can be applied to the general problem of shape separations which we demonstrate with a tetrapod material.

Cadmium Compounds↗