Vanadate induces p53 transactivation through hydrogen peroxide and causes apoptosis

Vanadium is a metal widely distributed in the environment. Although vanadate-containing compounds exert potent toxic effects on a wide variety of biological systems, the mechanisms controlling vanadate-induced adverse effects remain to be elucidated. The present study investigated the vanadate-induced p53 activation and involvement of reactive oxygen species (ROS) in p53 activation as well as the role of p53 in apoptosis induction by vanadate. Exposure of mouse epidermal JB6 cells to vanadate led to transactivation of p53 activity in a time- and dose-dependent manner. It also caused mitochondrial damage, apoptosis, and generated ROS. Scavenging of vanadate-induced H(2)O(2) by N-acetyl-l-cysteine (a general antioxidant) or catalase (a specific H(2)O(2) inhibitor), or the chelation of vanadate by deferoxamine, resulted in inhibition of p53 activation and cell mitochondrial damage. In contract, an increase in H(2)O(2) generation in response to superoxide dismutase or NADPH enhanced these effects caused by vanadate. Furthermore, vanadate-induced apoptosis occurred in cells expressing wild-type p53 (p53+/+) but was very weak in p53-deficient (p53-/-) cells. These results demonstrate that vanadate induces p53 activation mainly through H(2)O(2) generation, and this activation is required for vanadate-induced apoptosis.

Activation of AP-1 through the MAP kinase pathway: a potential mechanism of the carcinogenic effect of arenediazonium ions

Arenediazonium ions such as those found in the common mushroom Agaricus bisporus have been convincingly demonstrated to be tumorigenic. The specific mechanism of their tumorigenicity remains unclear. It has been shown that arenediazonium ions can be metabolized to aryl radicals, and that reaction of these aryl radicals with DNA produces aryl adducts. These metabolic processes also produce the reactive oxygen species superoxide and hydroxyl radicals which have been implicated in AP-1 activation. To further investigate the mechanism of tumorigenesis by arenediazonium ions, we studied the effect of a representative arenediazonium ion on AP-1 activation and phosphorylation of the signal transduction proteins ERK1, ERK2, JNK, and p38 kinase, both in vitro and in vivo. We also identified the specific radicals produced by spin trapping and ESR analysis. Here, it was found that p-methylbenzenediazonium ion (2a) induced a 16-fold increase in the extent of AP-1 activation at micromolar concentrations, and that this increase coincided with phosphorylation of the signaling kinases ERK1 and -2 and p38 kinase, but not JNK, in JB6 mouse epithelial cells. In vivo studies using AP-1 luciferase reporter-bearing transgenic mice supported the increase in the extent of AP-1 activation in 2a-treated mice over controls, and showed that this effect was different in different tissue types. The antioxidant N-acetylcysteine (NAC), a general antioxidant, showed an inhibitory effect on 2a-mediated AP-1 induction, while aspirin, a hydroxyl radical scavenger, had no effect. Spin trapping studies showed that while NAC suppressed radical formation from 2a, aspirin did not alter radical production from 2a. It appears that 3a, a carbon-centered radical formed from 2a, is responsible for AP-1-induced activation, and therefore, radical species that are not oxygen-centered are also capable of inducing AP-1. These results represent a step toward understanding the mechanism of tumorigenicity of arenediazonium ions.

High frequency of chromosome 3p deletion in histologically normal nasopharyngeal epithelia from southern Chinese

We have examined the presence of loss of heterozygosity (LOH) on chromosome 3p in histologically normal nasopharyngeal epithelia (NP), dysplastic lesions, and carcinoma of the nasopharynx from different ethnic and geographic regions. Microdissected normal NP from noncancerous individuals and nasopharyngeal carcinoma (NPC) samples from both the high-risk group (southern Chinese in Hong Kong) and two low-risk groups for NPC (central/northern Chinese in Anhui/Beijing and Caucasians in Toronto) were included. All NPC samples showed high incidence of 3p deletion (81-100%). High frequencies of LOH on 3p were also detected in normal NP (73.9%) and dysplastic lesions (75%) from the southern Chinese. Significant lower frequency of LOH on 3p was noted in normal NP from the low-risk groups (20%) than those from high-risk groups (P = 0.0003). The presence of such genetic alterations in the histologically normal NP and dysplastic lesions suggests that it is an early event in tumor development. The higher frequency of 3p LOH found in normal NP from southern Chinese compared with those from low-risk groups may be related to the distinct cancer incidence among these populations.

Participation of MAP kinase p38 and IkappaB kinase in chromium (VI)-induced NF-kappaB and AP-1 activation

Epidemiological studies demonstrate that environmental and occupational exposure of chromium(VI) [Cr(VI)] or Cr(VI)-containing particles can cause a number of human diseases, including inflammation and cancer. The biological mechanisms responsible for the initiation and progression of diseases resulting from exposure to Cr(VI) are not fully understood. The present studies evaluated the ability of Cr(IV) to induce activation of NF-kappaB and AP-1, two important transcription factors governing the expression of many early response genes involved in inflammation and carcinogenesis. The activation of NF-kappaB and AP-1 by Cr(IV) was dose dependent. Aspirin, a well-established antioxidant, substantially inhibited Cr(VI)-induced activation of both NF-kappaB and AP-1. SB202190, a specific inhibitor for p38, attenuated AP-1 activation induced by Cr(IV), whereas PD98059, a specific inhibitor for Erk, exhibited no effect on Cr(IV)-induced AP-1 activation. Blockage of NF-kappaB signaling pathway by a transient transfection of a dominant negative expressing vector for IkappaB kinase beta resulted in inhibition of Cr(IV)-induced NF-kappaB, but not AP-1 activation. These data suggest that the activation of AP-1 or NF-kappaB by Cr(IV) is through the involvement of MAP kinase or IKK pathway, respectively.

Activation of PKC is required for arsenite-induced signal transduction

Trivalent arsenic (arsenite) is a human carcinogen. However, the molecular mechanism of arsenite-induced carcinogenesis is still not well understood. In this study, we found that arsenite induced translocation of PKCepsilon, PKCdelta, and PKCalpha from cytosol to membranes. Rottlerin, a selective inhibitor for PKCdelta, and safingol, a specific inhibitor for PKCalpha, both markedly inhibited arsenite-induced AP-1 activity. These inhibitory effects by rottlerin and safingol appeared to be dose dependent. Arsenite-induced phosphorylation of Erks was inhibited by rottlerin, while safingol inhibited arsenite-induced phosphorylation of JNKs and p38 kinases. Dominant negative mutant transfectant of PKCepsilon markedly blocked arsenite-induced AP-1 activity and the phosphorylation of Erks, JNKs, and p38 kinases. These data demonstrate that PKCdelta, PKCepsilon, and PKCalpha mediate arsenite-induced AP-1 activation in JB6 cells through different MAP kinase (Erks, JNKs, and p38 kinases) pathways.

Causal influences in primate cerebral cortex during visual pattern discrimination

Anatomical studies of the visual cortex demonstrate the existence of feedforward, feedback and lateral pathways among multiple cortical areas. Yet relatively little evidence has previously been available to show the causal influences of these areas on one another during visual information processing. We simultaneously recorded event-related local field potentials (LFPs) from surface-to-depth bipolar electrodes at six sites in the ventral region of the right hemisphere visual cortex in a highly trained macaque monkey during performance of a visual pattern discrimination task. Applying a new statistical measure, the short-time directed transfer function (STDTF), to the LFP data set, we charted the changing strength and direction of causal influence between these cortical sites on a fraction-of-a-second time scale. We present results showing, for the first time, the dynamics of distinct feedforward, feedback and lateral influences in the ventral portion of the primate visual cortex during visual pattern processing.

The role of hydroxyl radical as a messenger in Cr(VI)-induced p53 activation

The present study investigates whether reactive oxygen species (ROS) are involved in p53 activation, and if they are, which species is responsible for the activation. Our hypothesis is that hydroxyl radical (.OH) functions as a messenger for the activation of this tumor suppressor protein. Human lung epithelial cells (A549) were used to test this hypothesis. Cr(VI) was employed as the source of ROS due to its ability to generate a whole spectrum of ROS inside the cell. Cr(VI) is able to activate p53 by increasing the protein levels and enhancing both the DNA binding activity and transactivation ability of the protein. Increased cellular levels of superoxide radicals (O(2)(-).), hydrogen peroxide (H(2)O(2)), and.OH radicals were detected on the addition of Cr(VI) to the cells. Superoxide dismutase, by enhancing the production of H(2)O(2) from O(2)(-). radicals, increased p53 activity. Catalase, an H(2)O(2) scavenger, eliminated.OH radical generation and inhibited p53 activation. Sodium formate and aspirin,.OH radical scavengers, also suppressed p53 activation. Deferoxamine, a metal chelator, inhibited p53 activation by chelating Cr(V) to make it incapable of generating radicals from H(2)O(2). NADPH, which accelerated the one-electron reduction of Cr(VI) to Cr(V) and increased.OH radical generation, dramatically enhanced p53 activation. Thus.OH radical generated from Cr(VI) reduction in A549 cells is responsible for Cr(VI)-induced p53 activation.

Predisposing factors in occupational lung cancer: inorganic minerals and chromium

Reactive oxygen species (ROS) have been implicated in the pathogenesis of cancer. Inhalation of inorganic minerals such as asbestos and crystalline silica, and metals such as arsenic, beryllium, chromium, nickel, and vanadium, may promote directly and indirectly enhanced generation of ROS at a persistent level in concert with chronic inflammation. Perpetual ROS generation can cause specific molecular changes resulting in the activation or inactivation of transcription factors that may alter gene expression leading to cell proliferation, differentiation, and carcinogenesis. The mechanisms involved in the signal transduction leading to these processes are the subject of intense investigation. In this review, some of the recent findings from our laboratories concerning key molecular events elicited by asbestos, crystalline silica, and chromium are presented. These include genotoxicity, DNA damage, lipid peroxidation, activation of transcription factors activator protein-1 (AP-1) or nuclear factor kappa B (NF-kappaB), and p53 or k-ras gene alterations. From these studies, it is evident that ROS signaling is critical for the responses of cytokines, growth factors, and activation or inactivation of transcription factors that promote carcinogenesis.

[Isolation and verification of Triticum aestivum-Eremopyrum orientale addition lines and substitution lines by GISH]

Eremopyrum is a potential genus in wheat improvement. To breed T. aestivum-Er. orientale additional and substitutional lines, chromosome number of 96 BC2F3 individuals were accounted. Fifteen plants with 2n = 43 and eight plants with 2n = 44 were checked out. GISH results of the individuals with 43 chromosomes showed that they blonged to three different monosomic additions. Two disomic additions, one double-monosomic addition, one trible-monosomic addition and one monosomic addition were found in the 2n = 44 individuals. One double-monosomic substitution and one monosomic substitution were obtained. We also proved that it is relatively easier to obtain addition lines in the selfing population than to obtain double-monosomic additions.

First determination of generalized polarizabilities of the proton by a virtual compton scattering experiment

Absolute differential cross sections for the reaction ep-->epgamma have been measured at a four-momentum transfer with virtuality Q2 = 0.33 GeV2 and polarization epsilon = 0.62 in the range 33.6 to 111.5 MeV/c for the momentum of the outgoing photon in the photon-proton center of mass frame. The experiment has been performed with the high-resolution spectrometers at the Mainz Microtron MAMI. From the photon angular distributions, two structure functions which are a linear combination of the generalized polarizabilities have been determined for the first time.

Human immunodeficiency virus type 1 shedding pattern in semen correlates with the compartmentalization of viral Quasi species between blood and semen

High levels of human immunodeficiency virus (HIV) type 1 have been detected in semen at all stages of disease. However, it is not clear whether HIV-1 is shed in semen continuously or intermittently. In a prospective longitudinal study, viral RNA was measured weekly for 10 weeks in semen and blood of HIV-seropositive subjects. Results showed three different patterns of HIV-1 shedding in semen: none (28%), continuous (28%), and intermittent (44%). In contrast, there was no change in blood plasma virus load during the study period. Phylogenetic analysis of the envelope sequences of HIV-1 RNA in semen and blood revealed distinct virus populations in semen and blood of intermittent shedders but similar virus populations in the semen and blood of continuous shedder. These results indicate for the first time that HIV-1 is shed primarily in an intermittent manner and that shedding patterns of HIV-1 in semen are related to compartmentalization of HIV-1 between semen and blood.

Anomalous diffusion and the first passage time problem

We study the distribution of the first passage time (FPT) in Levy type anomalous diffusion. Using the recently formulated fractional Fokker-Planck equation we obtain three results. (1) We derive an explicit expression for the FPT distribution in terms of Fox or H functions when the diffusion has zero drift. (2) For the nonzero drift case we obtain an analytical expression for the Laplace transform of the FPT distribution. (3) We express the FPT distribution in terms of a power series for the case of two absorbing barriers. The known results for ordinary diffusion (Brownian motion) are obtained as special cases of our more general results.

Arsenic mediates cell proliferation and gene expression in the bladder epithelium: association with activating protein-1 transactivation

Although the mechanism of action has not yet been defined, epidemiological studies have demonstrated an association between elevated arsenic levels in drinking water and the incidence of urinary bladder transitional cell carcinomas. In the current studies, we demonstrate that mice exposed to 0.01% sodium arsenite in drinking water develop hyperplasia of the bladder urothelium within 4 weeks of exposure. This was accompanied by the accumulation of inorganic trivalent arsenic, and to a lesser extent dimethylarsinic acid, in bladder tissue, as well as a persistent increase in DNA binding of the activating protein (AP)-1 transcription factor. AP-1 transactivation by arsenic also occurred in bladders of transgenic mice containing an AP-1 luciferase reporter. Consistent with these in vivo observations, arsenite increased cell proliferation and AP-1 DNA binding in a human bladder epithelial cell line. Gene expression studies using RNase protection assays, reverse transcription-PCR, and cDNA microarrays indicated that arsenite alters the expression of a number of genes associated with cell growth, such as c-fos, c-jun, and EGR-1, as well as cell arrest, such as GADD153 and GADD45. The proliferation-enhancing effect of arsenic on uroepithelial cells likely contributes to its ability to cause cancer.

Short-window spectral analysis of cortical event-related potentials by adaptive multivariate autoregressive modeling: data preprocessing, model validation, and variability assessment

In this article we consider the application of parametric spectral analysis to multichannel event-related potentials (ERPs) during cognitive experiments. We show that with proper data preprocessing, Adaptive MultiVariate AutoRegressive (AMVAR) modeling is an effective technique for dealing with nonstationary ERP time series. We propose a bootstrap procedure to assess the variability in the estimated spectral quantities. Finally, we apply AMVAR spectral analysis to a visuomotor integration task, revealing rapidly changing cortical dynamics during different stages of task processing.

Toxoplasma gondii catalase: are there peroxisomes in toxoplasma?

The intracellular protozoan parasite Toxoplasma gondii, like all members of the phylum Apicomplexa, is known to possess many organelles: in addition to mitochondria and the compartments of the secretory pathway, there is a reduced chloroplast (the apicoplast) and the phylum-specific components of the apical complex: dense granules, micronemes and rhoptries. Conspicuously missing so far are microbodies, organelles that can be found in nearly all eukaryotic organisms. Microbodies show a large variation with regard to their size, number and contents, depending on the organism and cell type. One marker enzyme of this single membrane-bound organelle is catalase, which is responsible for the degradation of hydrogen peroxide to water and oxygen. The EST project in T. gondii revealed the existence of two overlapping clones which showed similarity with catalase, and these were used to clone the corresponding gene. The predicted sequence of T. gondii catalase has -AKM at the C terminus, which falls within the consensus of the PTS1 peroxisomal targeting signal. Southern blot analysis confirmed the presence of a single copy gene. Northern and western blot analyses showed that the catalase gene is transcribed and translated. Immunofluorescence assays using an antibody raised against a catalase peptide identified a distinct structure towards the apical end, but other catalase-specific antibodies failed to confirm this localisation. Cell fractionations indicated that the majority of the enzyme was in the cytosol. The fusion of the C-terminal twelve amino acids, including AKM, or the canonical peroxisomal targeting signal, -SKL, to GFP resulted in predominantly cytosolic localization in T. gondii. There was therefore no evidence for membrane-bound peroxisomes in Toxoplasma.

Premature structural changes at replication origins in a yeast minichromosome maintenance (MCM) mutant

The Cdc7p protein kinase in the budding yeast Saccharomyces cerevisiae is thought to help trigger DNA replication by modifying one or more of the factors that assemble at replication origins (ARSs). To investigate events catalyzed by Cdc7p, we compared the structure of replication origins in cells containing conditional mutations in Cdc7p and Cdc8p, a thymidylate kinase that is required for DNA synthesis. High resolution genomic footprinting indicated that the presumptive lagging strand template in ARS1 became highly sensitive to KMnO(4) modification after the CDC7 execution point. These results suggested that Cdc7p triggers DNA unwinding. The transition from late G(1) phase to the CDC7 execution point and from the CDC7 to the CDC8 execution points was accompanied by small but ARS-dependent changes in DNA topology. These results suggested that DNA unwinding before the CDC8 execution point either is highly localized or that the torsional stress associated with initial DNA unwinding is minimized by compensatory protein-DNA structural changes. The ARS DNA structural attributes evident in cells blocked at the CDC8 execution point were also evident in alpha-factor-blocked, G(1) phase cells containing the CDC7 bypass mutant mcm5/cdc46-bob1. This result strongly suggests that the structural changes during the transition from the CDC7 to CDC8 execution points depend on the Cdc7p protein kinase and involve alteration of the minichromosome maintenance protein complex.

Age variations in the properties of human tibial trabecular bone and cartilage

Initiated and motivated by clinical and scientific problems such as age-related bone fracture, prosthetic loosening, bone remodeling, and degenerative bone diseases, much significant research on the properties of trabecular bone has been carried out over the last two decades. This work has mainly focused on the central vertebral trabecular bone, while little is known about age-related changes in the properties of human peripheral (tibial) trabecular bone. Knowledge of the properties of peripheral (tibial) trabecular bone is of major importance for the understanding of degenerative diseases such as osteoarthrosis and osteoporosis, and for the design, fixation and durability of total joint prosthesis. The specific aims of the present studies were: 1) to investigate normal age-related variations in the mechanical, physical/compositional, and structural properties of human tibial trabecular bone; and 2) to investigate the age-related and osteoarthrosis-related changes in the mechanical properties of the human tibial cartilage-bone complex; and 3) to evaluate mutual associations among various properties. Normal specimens from human autopsy proximal tibiae were used for investigation of age variations in the properties of trabecular bone and the cartilage-bone complex, and osteoarthrotic specimens were used for the investigation of changes in the mechanical properties of the cartilage-bone complex induced by this disease process. The mechanical properties and physical/compositional properties of trabecular bone were quantified by means of standard techniques, and trabecular bone structure was quantified by means of unbiased three-dimensional methods. The present study demonstrated that the mechanical properties, such as Young's modulus, ultimate stress, ultimate strain and failure energy, and the densities, such as apparent, apparent ash and collagen densities of human tibial trabecular bone have significant relationships with age. Tissue density and mineral concentration remain constant throughout life. Trabecular bone is tougher in the younger age, i.e. fracture requires more energy. Collagen density was the single best predictor of failure energy, and collagen concentration was the only predictor of ultimate strain. The decrease in mechanical properties of trabecular bone mainly is a consequence of the loss of trabecular bone substance. This study showed that the degree of anisotropy (preferential orientation of trabeculae), mean marrow space volume, and bone surface-to-volume ratio increased significantly with age. Bone volume fraction, mean trabecular volume, and bone surface density decreased significantly with age. Connectivity did not have a general relationship with age, yet a trend exists. Age-related changes in the microstructural properties had the same trends for both medial and lateral condyles of the tibia. The observed increase of anisotropy may be interpreted as the consequence of structural adaptation secondary to age-induced bone loss. The aging trabeculae align more strongly to the primary direction, which is parallel to the longitudinal loading axis of the tibia. The mechanical properties of the normal cartilage and bone vary with age and respond simultaneously to mechanical loading. Both cartilage and bone in early-stage OA are mechanically inferior to normal, and OA cartilage and bone have lost their unit function to mechanical loading.

Cell cycle-dependent phosphorylation of centrosomes: localization of phosphopeptide specific antibodies to the centrosome

The microtubule nucleation capacity of the centrosome increases dramatically as cells progress from interphase into mitosis. The increase in nucleation capacity of the centrosome correlates with the cell cycle-dependent localization of the mitotic protein monoclonal-2 (MPM-2) phosphoepitope-specific antibody to the mitotic centrosome. Therefore, the phosphorylation state of centrosomal components may regulate the microtubule nucleation capacity of this organelle during mitosis. Neither the identity of the MPM-2 kinase(s) nor all of the MPM-2-reactive phosphoproteins associated with the centrosome have been fully elucidated. Only recently have the characteristics of the MPM-2 epitope site been defined, and we used this information to prepare polyclonal antibodies against synthetic phosphopeptides containing potential MPM-2 epitopes derived from the sequences of two MPM-2-reactive proteins, topoisomerase II, and microtubule associated protein 1B (MAP1B). We demonstrate that these phosphopeptide-specific antibodies also localize to the centrosome in a cell cycle-dependent fashion. Thus, polyclonal antibodies have been generated against defined phosphopeptides that reiterate many of the immunofluorescence staining properties exhibited by the MPM-2 antibody. These new phosphopeptide-specific antibodies will provide additional probes to examine the phosphorylation of centrosomal components and the functional consequences of their phosphorylation during mitosis.

[Study on the morphological processing of classical swine fever virus in cultured cells]

An infected mode between the Thiverval strain and Chinese strain of CSFV and MPK cells are established. The morphological structure and processing of different strains(T strain, C strain and F strain) of CSFV were studied by ultra-thin section electron microscopy. The virions of CSFV are roughly round and approximately 70 nm in diameter with a 40 nm core, and are wraped by membrane. The distinctive pathway of the maturation and release of CSFV are observed. Virons on different deverloping state and the pathologic changes of host cells have also been reported in this paper.

[Molecular cloning and expression of E2 gene of the Chinese classical swine fever virus(shimen strain) and preliminary studies of its DNA vaccine]

A 1.1 bp fragment of E2 gene of Chinese classical swine fever virus(CSFV) Shimen strain, a standard virulent strain, was amplified by RT-PCR from total RNA of cell cultures infected by CSFV, and cloned into pGEM T vector. The nucleotide sequence of this fragment was sequenced by Sanger's method and the amino acid sequence was deduced. Compared with the corresponding region of Alfort, Brescia and C strain of CSFV, the nucleotide sequence homology is 84.7%, 92.6% and 95.2% respectively, and the amino acid sequence 89.4%, 92.6% and 94.6%, respectively, we subcloned 1.1 bp of E2 gene cDNA into baculovirus transfer vector and successfully constructed two recombinant baculoviruses expressing GST-E2 and GST-GFP-E2 fusion protein respectively by homologous recombination in sf-9 cell. Furthermore, we also constructed recombinant eukaryotic expression vector pcE2 containing E2 gene in frame and transfected COS-7 cell by lipofectamine, the indirect immunofluorescence assay (IFA) showed that the expressed E2 protein can be recognized by E2 specific monoclonal antibody the pcE2 DNA was directly injected into BALB/c mice intramuscular(i.m.) and the CSFV E2-specific antibodies was measured by enzyme-linked immunosorbent assay(ELISA) the ELISA results indicated the E2-specific antibodies was induced in inoculated mice and virus neutralization assays also indicate single inoculations of plasmids expressing CSFV E2 glycoprotein raised neutralizing antibody in BALB/c mice. these results will be beneficial to investigate the possibility of DNA vaccine against CSFV.

Analysis of tetramethylpyrazine in Ephedrae herba by gas chromatography-mass spectrometry and high-performance liquid chromatography

A simple and reliable HPLC method was developed for the determination of 2,3,5,6-tetramethylpyrazine (TMP) in Ephedrae herba. Further identification of TMP was achieved using GC-MS. The mobile phase used was methanol-water-35% acetic acid (35:65:0.5, v/v/v) at a flow-rate of 0.8 ml/min. The detection wavelength was set at 290 nm. The linear range of the peak area calibration curve of TMP was 2.64-264 mg/l (r=0.9987) and the recovery for TMP in Ephedrae herba extracts was 101.1-106.9%. The relative standard deviations of retention time and peak area were 0.18 and 1.5% (n=6), respectively. The detection limit of TMP was 0.03 mg/l. The contents of TMP in Ephedrae herba could easily be determined within 10 min.

Integrated approach to the assessment of long range correlation in time series data

To assess whether a given time series can be modeled by a stochastic process possessing long range correlation, one usually applies one of two types of analysis methods: the spectral method and the random walk analysis. The first objective of this work is to show that each one of these methods used alone can be susceptible to producing false results. We thus advocate an integrated approach which requires the use of both methods in a consistent fashion. We provide the theoretical foundation of this approach and illustrate the main ideas using examples. The second objective relates to the observation of long range anticorrelation (Hurst exponent H < 1/2) in real world time series data. The very peculiar nature of such processes is emphasized in light of the stringent condition under which such processes can occur. Using examples, we discuss the possible factors that could contribute to the false claim of long range anticorrelations, and demonstrate the particular importance of the integrated approach in this case.

Quantitative immunochemistry on neuronal loss, reactive gliosis and BBB damage in cortex/striatum and hippocampus/amygdala after systemic kainic acid administration

Cell specific markers were quantified in the hippocampus, the amygdala/pyriform cortex, the frontal cerebral cortex and the striatum of the rat brain after systemic administration of kainic acid. Neuron specific enolase (NSE) reflects loss of neurons, glial fibrillary acidic protein (GFAP) reflects reactive gliosis, and brain levels of serum proteins measures blood-brain-barrier permeability. While the concentration of NSE remained unaffected in the frontal cerebral cortex and the striatum, their GFAP content increased during the first three days. In the hippocampus and amygdala, NSE levels decreased significantly. GFAP levels in the hippocampus were unaffected after one day and decreased in the amygdala/pyriform cortex. After that, GFAP increased strikingly until day 9 or, in the case of amygdala/pyriform cortex, even longer. This biphasic time course for GFAP was accompanied by a decrease of S-100 during days 1-9 followed by a significant increase at day 27 above the initial level. The regional differences in GFAP and S-100 could result from the degree of neuronal degeneration, the astrocytic receptor set-up and/or effects on the blood-brain barrier.

Antioxidant properties of pyrrolidine dithiocarbamate and its protection against Cr(VI)-induced DNA strand breakage

Pyrrolidine dithiocarbamate (PDTC) is considered an antioxidant and is frequently used to study the role of free radical reactions in various biological processes and against free radical-induced cellular injuries. However, its antioxidant properties are not characterized. In this study, electron spin resonance (ESR) was used to investigate the antioxidant potential of PDTC with hydroxyl radical (*OH) and superoxide anion radicals (O2*-). The Fenton reaction [Fe(II) + H2O2 --> Fe(II) + *OH + OH-)] and xanthine and xanthine oxidase were used as sources of *OH and O2*- radicals, respectively. The results show that PDTC effectively scavenges *OH radicals with a reaction rate constant of approximately 2.73 x 10(10) M(-1) s(-1), which is comparable to other efficient *OH radical scavengers, such as ascorbate and glutathione. PDTC is also able to scavenge O2*- radicals. Through its antioxidant properties, PDTC protects against Cr(VI)-induced DNA strand breakage.

Quantification of age-related changes in the structure model type and trabecular thickness of human tibial cancellous bone

Structure model type and trabecular thickness are important characteristics in describing cancellous bone architecture. It has been qualitatively observed that a radical change of trabeculae from plate-like to rod-like occurs in aging, bone remodeling, and osteoporosis. Thickness of trabeculae has traditionally been measured using model-based histomorphometric methods on two-dimensional (2-D) sections. However, no quantitative study has been published based on three-dimensional (3-D) methods on the age-related changes in structure model type and trabecular thickness for human peripheral (tibial) cancellous bone. In this study, 160 human proximal tibial cancellous bone specimens from 40 normal donors, aged 16 to 85 years, were collected. These specimens were micro-computed tomography (micro-CT) scanned, then the micro-CT images were segmented using optimal thresholds. From accurate 3-D data sets, structure model type and trabecular thickness were quantified by means of novel 3-D methods. Structure model type was assessed by calculating the structure model index (SMI). The SMI was quantified based on a differential analysis of the triangulated bone surface of a structure. This technique allows quantification of structure model type, such as plate, rod objects, or mixture of plates or rods. Trabecular thickness is calculated directly from 3-D images, which is especially important for an a priori unknown or changing structure. Furthermore, 2-D trabecular thickness was also calculated based on the plate model. Our results showed that structure model type changed towards more rod-like in the elderly, and that trabecular thickness declined significantly with age. These changes become significant after 80 years of age for human tibial cancellous bone, whereas both properties seem to remain relatively unchanged between 20 and 80 years. Although a fairly close relationship was seen between 3-D trabecular thickness and 2-D trabecular thickness, real 3-D trabecular thickness was significantly underestimated using 2-D method.

Antioxidant properties of (-)-epicatechin-3-gallate and its inhibition of Cr(VI)-induced DNA damage and Cr(IV)- or TPA-stimulated NF-kappaB activation

Electron spin resonance (ESR) spin trapping was utilized to investigate the scavenging effects on hydroxyl radicals (*OH) and superoxide radicals (O2*-) by (-)-epigallocatechin-3-gallate (EGCG), one of the major anticancer compounds in tea. The spin trap used was 5,5-dimethyl-pyrroline N-oxide (DMPO). The Fenton reaction (Fe2+ + H2O2-->Fe3+ + *OH + OH-) was used as a source of *OH radicals. EGCG efficiently scavenges *OH radicals with reaction rate of 4.62 x 10(11) M(-1)sec(-1), which is an order of magnitude higher than several well recognized antioxidants, such as ascorbate, glutathione and cysteine. It also scavenges O2*- radicals as demonstrated by using xanthine and xanthine oxidase system as a source of O2*- radicals. Through its antioxidant properties, EGCG exhibited a protective effect against DNA damage induced by Cr(VI). EGCG also inhibited activation of nuclear transcription factor NF-kappaB induced by Cr(IV) and 12-o-tetradecanoylphorbol-13-acetate (TPA). The present studies provide a mechanistic basis for the reported anticarcinogenic properties of EGCG and related tea products.

On the role of hydroxyl radical and the effect of tetrandrine on nuclear factor--kappaB activation by phorbol 12-myristate 13-acetate

Nuclear factor kappaB (NF-kappaB) is considered to be an important target for therapeutic intervention because of its role in the regulation of proinflammatory and profibrotic mediators. The present study examined the role of hydroxyl (*OH) radical and the effect of tetrandrine, an alkaloid extracted from the Chinese medicinal herb Stephania tetrandra, on NF-kappaB activation by a tumor promoter, phorbol 12-myristate 13-acetate (PMA) in human lymphoid T cells (ie, Jurkat cells). Exogenous superoxide dismutase (SOD) enhanced the NF-kappaB activation by PMA, while catalase blocked it. Formate, a scavenger of *OH radical, also was inhibitory, as was deferoxamine, a metal chelator. These data suggest an important role of *OH radical in PMA-induced NF-kappaB activation. Incubation of the cells with tetrandrine prior to the stimulation of the cells was found to inhibit PMA-induced NF-kappaB activation. Tetrandrine activity was so potent that 50 microM of tetrandrine was sufficient to inhibit activation of NF-kappaB completely. Electron spin resonance (ESR) spin trapping was used to investigate the antioxidant action of tetrandrine using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap. Tetrandrine is an antioxidant for both *OH and superoxide (O2-)radicals. The reaction rate constant of tetrandrine with *OH is 1.4 x 10(10) M(-1)sec(-1), which is comparable with several well established antioxidants, such as ascorbate, glutathione, and cysteine. The Fenton reaction (Fe(II) + H2O2-->Fe(III) + *OH + OH-) and xanthine/xanthine oxidase were used as sources of *OH and O2- radicals. The free radical scavenging activity of tetrandrine is responsible for its inhibition of PMA-induced NF-kappaB activation.

The ephrin VAB-2/EFN-1 functions in neuronal signaling to regulate epidermal morphogenesis in C. elegans

The Eph receptor VAB-1 is required in neurons for epidermal morphogenesis during C. elegans embryogenesis. Two models were proposed for the non-autonomous role of VAB-1: neuronal VAB-1 might signal directly to epidermis, or VAB-1 signaling between neurons might be required for epidermal development. We show that the ephrin VAB-2 (also known as EFN-1) is a ligand for VAB-1 and can function in neurons to regulate epidermal morphogenesis. In the absence of VAB-1 signaling, ephrin-expressing neurons are disorganized. vab-2/efn-1 mutations synergize with vab-1 kinase alleles, suggesting that VAB-2/EFN-1 may partly function in a kinase-independent VAB-1 pathway. Our data indicate that ephrin signaling between neurons is required nonautonomously for epidermal morphogenesis in C. elegans.

Role of reactive oxygen species and p53 in chromium(VI)-induced apoptosis

Apoptosis is a programmed cell death mechanism to control cell number in tissues and to eliminate individual cells that may lead to disease states. The present study investigates chromium(VI) (Cr(VI))-induced apoptosis and the role of reactive oxygen species (ROS) and p53 in this response. Treatment of human lung epithelial cells (A549) with Cr(VI) caused apoptosis as measured by DNA fragmentation, mitochondria damage, and cell morphology. Cr(VI)-induced apoptosis is contributed to ROS generation, resulting from cellular reduction of Cr(VI) as measured by flow cytometric analysis of the stained cells, oxygen consumption, and electron spin resonance spin trapping. Scavengers of ROS, such as catalase, aspirin, and N-acetyl-L-cysteine, decreased Cr(VI)-induced apoptosis, whereas NADPH and glutathione reductase, enhancers of Cr(VI)-induced ROS generation, increased it. p53 is activated by Cr(VI), mostly by ROS-mediated free radical reactions. Cr(VI)-induced ROS generation occurred within a few minutes after Cr(VI) treatment of the cells, whereas p53 induction took at least 5 h. The level of Cr(VI)-induced apoptosis was similar in both p53-positive cells and p53-negative cells independent of p53 status in the early stage (0-3 h) of Cr(VI) treatment. However, at the later stage (3-24 h), the level of the apoptosis is higher in p53-positive cells than in p53-negative cells. These results suggest that ROS generated through Cr(VI) reduction is responsible to the early stage of apoptosis, whereas p53 contributes to the late stage of apoptosis and is responsible for the enhancement of Cr(VI)-induced apoptosis at this stage.

Vanadate induces apoptosis in epidermal JB6 P+ cells via hydrogen peroxide-mediated reactions

Apoptosis is a physiological mechanism for the control of DNA integrity in mammalian cells. Vanadium induces both DNA damage and apoptosis. It is suggested that vanadium-induced apoptosis serves to eliminate DNA-damaged cells. This study is designed to clarify a role of reactive oxygen species in the mechanism of apoptosis induced by vanadium. We established apoptosis model with murine epidermal JB6 P+ cells in the response to vanadium stimulation. Apoptosis was detected by a cell death ELISA assay and morphological analysis. The result shows that apoptosis induced by vanadate is dose-dependent, reaching its saturation level at a concentration of 100 microM vanadate. Vanadyl (IV) can also induce apoptosis albeit with lesser potency. A role of reactive oxygen species was analyzed by multiple reagents including specific scavengers of different reactive oxygen species. The result shows that vanadate-induced apoptosis is enhanced by NADPH, superoxide dismutase and sodium formate, but was inhibited by catalase and deferoxamine. Cells exposed to vanadium consume more molecular oxygen and at the same time, produce more H2O2 as measured by the change in fluorescence of scopoletin in the presence of horseradish peroxidase. This change in oxygen consumption and H2O2 production is enhanced by NADPH. Taken together, these results show that vanadate induces apoptosis in epidermal cells and H2O2 induced by vanadate plays a major role in this process.

Antioxidant properties of aspirin: characterization of the ability of aspirin to inhibit silica-induced lipid peroxidation, DNA damage, NF-kappaB activation, and TNF-alpha production

Electron spin resonance (ESR) was used to investigate the reaction of aspirin toward reactive oxygen species, such as hydroxyl radicals (*OH), superoxide radicals (O2-) and H2O2. The Fenton reaction (Fe(II) + H2O2 ---> FE(III) + *OH + OR) was used as a source of *OH radicals. The results show that aspirin is an efficient *OH radical scavenger with a reaction rate constant of k = 3.6 x 10(10) M(-1) sec(-1), which is faster than several well established antioxidants, such as ascorbate, glutathione and cysteine. However, aspirin is not a good scavenger for O2- or H2O2. Through its antioxidant property, aspirin exhibited a protective effect against silica-induced lipid peroxidation and DNA strand breakage. Aspirin also inhibited the activation of nuclear transcription factor-kappaB induced by silica, lipopolysaccharide or the transition metal, Fe(II), as demonstrated by electrophoretic mobility shift assay. The results show that aspirin functions as an antioxidant via its ability to scavenge *OH radicals. This antioxidant property may explain some of its various physiological and pharmacological actions.

[HLA-DRB1 typing by PCR-sequence specific primers for paternity determination]

HLA-DRB1 typing by PCR-SSP technique was first used for paternity testing. The analysis of 42 paternity cases shows that this identification method is simple, fast and reliable and has high exclusion probability of paternity (66.3%). This method can also be applied to the study of transplantation, HLA associated disease and anthropogenesis.

Genetic alterations in pediatric high-grade astrocytomas

High-grade astrocytomas are tumors that are uncommon in children. Relatively few studies have been performed on their molecular properties and so it is not certain whether they follow different genetic pathways from those described in adult diffuse astrocytomas. In this study, we evaluated 24 pediatric high-grade astrocytomas (11 anaplastic astrocytomas and 13 glioblastomas) all of which were sporadic and primary. We studied mutations of p53, phosphatase and tensin homolog (PTEN), loss of heterozygosity (LOH) of chromosomes 17p13, 9p21 and 10q23-25, amplification of epidermal growth factor receptor (EGFR), and overexpression of EGFR and p53 protein. In addition, we searched for microsatellite instability (MSI) by using MSI sensitive and specific microsatellite markers. p53 mutations were found in 38% (9/24) of the high-grade astrocytomas and all brain stem tumors except 2 (71%, 5/7) had p53 mutations. PTEN mutations were found in 8% (2/24) of high-grade astrocytomas. However, no EGFR amplification was found in any of them. LOH was found at 17p13.1 in 50% (3/6 informative tumors), 9p21 in 83% (5/6 informative tumors), and 10q23-25 in 78% (7/9 informative tumors). Four tumors showed MSI, and 2 of them that showed widespread MSI were regarded as tumors with replication error (RER+) phenotype. All 4 tumors with MSI showed concurrent LOH of 9p21 and 10q23-25. Combining gene alterations, LOH, MSI, and gene mutations, inactivation of both alleles of PTEN and p53 was found in 57% (4/7 informative tumors) and 50% (3/6 informative tumors) of the cases respectively. We conclude that development of pediatric high-grade astrocytomas may follow pathways different from the primary or secondary paradigm of adult glioblastomas. In a subset of these tumors, genomic instability was also implicated.

The impact of genetic removal of GFAP and/or vimentin on glutamine levels and transport of glucose and ascorbate in astrocytes

The importance of the intermediate filament (IF) proteins glial fibrillary acidic protein (GFAP) and vimentin for astrocyte function was studied by investigating astrocytes prepared from GFAP-/- and/or vimentin-/- mice. The rate of glucose uptake through facilitative hexose transporters was not affected by depletion of GFAP or vimentin. Similarly, the absence of these IF proteins did not affect ascorbate uptake, under control or cyclic AMP-stimulated conditions, or ascorbate efflux through volume-sensitive organic anion channels. However, compared with wild-type astrocytes, glutamine concentrations were increased up to 200% in GFAP-/- astrocytes and up to 150% in GFAP+/- astrocytes and this increase was not dependent on the presence of vimentin. GFAP-/- astrocytes in culture still contain IFs (made of vimentin and nestin), whereas GFAP-/- vim-/- cultured astrocytes lack IFs. Thus, glutamine levels appear to correlate inversely with GFAP, rather than depend on the presence of IFs per se. Furthermore, the effect of GFAP is dose-dependent since the glutamine concentration in GFAP+/- astrocytes falls between those in wild-type and GFAP-/- astrocytes.

Freshly fractured crystalline silica induces activator protein-1 activation through ERKs and p38 MAPK

The transcription factor activator protein-1 (AP-1) reportedly plays an important role in the induction of neoplastic transformation and multiple genes involved in cell proliferation, differentiation, and inflammation. To investigate the mechanisms of silica-induced carcinogenesis, AP-1-luciferase reporter transgenic mice were used as an in vivo model, whereas the JB6 mouse epidermal cell line and a rat lung epithelial cell line were employed as in vitro models to study the effects of silica at the molecular level. Freshly fractured silica caused an 8-fold increase in AP-1 activity in JB6 cells and a 2.5-fold increase in rat lung epithelial cells. The induction of AP-1 activity in cultured cell lines was time- and dose-dependent. Intratracheal administration of silica was also able to induce AP-1 transactivation in transgenic mice. AP-1 activation was first observed at 2 days after silica administration and reached its maximum at 3 days post-exposure of the mice to silica. The signal transduction pathways for AP-1 activation were also investigated using these cell lines. The results demonstrate that freshly fractured silica stimulates mitogen-activated protein kinase (MAPK) family members, as determined by the phosphorylation of p38 MAPK and extracellular signal-regulated protein kinases (ERKs). Inhibition of ERKs with PD98059 or of p38 with SB203580 significantly inhibited silica-induced AP-1 activation. These findings demonstrate for the first time that freshly fractured silica induces AP-1 activation, which may be mediated through p38 MAPK and ERK pathways. Unraveling the complex mechanisms associated with these events may provide insights into the initiation and progression of silica-induced carcinogenesis.

Quantitative assessment of Parkinson's disease deficits

OBJECTIVE

To quantitatively analyze the tremor and rigidity due to Parkinson's disease.

METHODS

38 patients with Parkinson's disease (PD) ranging in age from 45 to 72 years and 211 normal subjects aged from 16 to 76 years were investigated. The frequency and range of tremor, the muscle tone of the upper limbs in elbow were detected by a computerized video motion detecting system and a new invented apparatus which can detects skeletal muscle tone.

RESULTS

For the PD patients, the frequency of resting tremors was detected in 4 to 6 per second. For extensor and flexor in the PD patients, the value of muscle tone was higher than that of normal subjects and the value of muscle tone in flexor was higher than that of extensor. The rigidity increased gradually with repeat passive movement. The curves of rigidity were shown on computer screen or printed out. The data of rigidity were compared with the M-A Scale. A patient who was suspected to suffer from PD above by the equipments and found the muscle tone was higher than normal. In another PD patient the rigidity was obvious at one side and the muscle tone in "normal side" was also high. These equipments were used to record changes of rigidity and tremor in one more PD patient taking with different drugs in order to see the drug effect.

CONCLUSION

Quantitative methods are useful to analyse the motion disorders due to PD.

Antioxidant properties of aspirin: characterization of the ability of aspirin to inhibit silica-induced lipid peroxidation, DNA damage, NF-kappaB activation, and TNF-alpha production

Electron spin resonance (ESR) was used to investigate the reaction of aspirin toward reactive oxygen species, such as hydroxyl radicals (*OH), superoxide radicals (O2-) and H2O2. The Fenton reaction (Fe(II) + H2O2 ---> FE(III) + *OH + OR) was used as a source of *OH radicals. The results show that aspirin is an efficient *OH radical scavenger with a reaction rate constant of k = 3.6 x 10(10) M(-1) sec(-1), which is faster than several well established antioxidants, such as ascorbate, glutathione and cysteine. However, aspirin is not a good scavenger for O2- or H2O2. Through its antioxidant property, aspirin exhibited a protective effect against silica-induced lipid peroxidation and DNA strand breakage. Aspirin also inhibited the activation of nuclear transcription factor-kappaB induced by silica, lipopolysaccharide or the transition metal, Fe(II), as demonstrated by electrophoretic mobility shift assay. The results show that aspirin functions as an antioxidant via its ability to scavenge *OH radicals. This antioxidant property may explain some of its various physiological and pharmacological actions.

[Direct determination of purine bases in tea by reversed-phase high performance liquid chromatography]

A reversed-phase high performance liquid chromatographic(RP-HPLC) method for the direct determination of three purine bases(theobromin, theophyllin and caffeine) in tea was developed. An ODS column with Zorbax SB-C18(4.6 mm i.d. x 250 mm, 5 microns) was employed. The aqueous solution of methanol containing 0.05% of acetic acid and 0.25% of N,N-dimethylformamide(DMF) was used as eluent with a flow rate of 0.8 mL/min. In this method, the aqueous extract of tea can be injected into HPLC directly, but in current HPLC methods for purine bases the coexisted tea polyphenols must be pre-separated. The three purine bases in tea were separated without any interference from the coexisted tea polyphenols. This method is simple (without any special sample pretreatment) and sensitive with detection limits (S/N = 3) of 0.7, 0.9 and 1.8 mg/L for theobromin, theophyllin and caffeine respectively. The linear range of the calibration curve of peak area for the three purine bases were from 6 mg/L to 1,000 mg/L with a correlation coefficient (r) of 0.998-0.999.

Induction of TNFalpha in macrophages by vanadate is dependent on activation of transcription factor NF-kappaB and free radical reactions

Vanadium-induced TNFalpha production is believed to play an important role in respiratory disease associated with air pollution and occupational exposure. While vanadium is able to induce TNFalpha in macrophages or airway epithelial cells, the underlying mechanism is not well defined. In the present study, mechanisms of vanadate-induced TNFalpha production were analyzed in the murine Raw264.7 cells. Vanadate induces a significant amount of TNFalpha at both the protein and mRNA levels, and the induction is vanadate dose-dependent. The mechanism analysis was focused on transcriptional regulation of TNFalpha gene by vanadate. Transient transfection studies show that the TNFalpha gene promoter was activated by vanadate and this activation was associated with an increase in DNA binding activity of the nuclear factor-kappaB (NF-kappaB). Mutation of the NF-kappaB binding site in the gene promoter led to a loss of the promoter responsiveness to vanadate, indicating requirement of NF-kappaB. This is supported by evidence that inhibition of NF-kappaB activation by SN50, a specific NF-kappaB inhibitor, resulted in a decrease in the TNFalpha production. A role of reactive oxygen species (ROS) was explored in vanadate activity. The result shows that vanadate-induced TNFalpha production is elevated by NADPH, which enhances vanadate-mediated generation of ROS, but is inhibited by an antioxidant, N-acetyl-L-cysteine (NAC). Modification of TNFalpha production is associated with an enhancement or a repression of NF-kappaB activity by NADPH or NAC, respectively. Taken together, these results indicate that: (a) activation of the TNFalpha gene promoter contributes to the vanadate-induced TNFalpha production; (b) NF-kappaB is required for the vanadate-induced promoter activity of TNFalpha gene; (c) free radical reactions are involved in the vanadate-induced TNFalpha production and NF-kappaB activation.

Rapid, direct determination of polyphenols in tea by reversed-phase column liquid chromatography

Column liquid chromatography on a C18-bonded silica column with water-methanol-acetic acid as eluent was used to determine polyphenols and caffeine in tea. Without any pretreatment, catechin, epicatechin gallate, epigallocatechin gallate, epigallocatechin, epicatechin and caffeine were separated successfully within 15 min. The detection limits (S/N = 3) of polyphenols studied were 1.8-24 mg/l at a detection wavelength 270 nm. The linear range of the peak area calibration curves for the analytes were over two orders of magnitude with a correlation coefficient of 0.996-0.999. Using this method, some Chinese tea samples were analyzed with a good reproducibility (RSD are below 5%).

Vanadate induction of NF-kappaB involves IkappaB kinase beta and SAPK/ERK kinase 1 in macrophages

The present studies investigated the signaling pathways of vanadate, a vanadium ion with +5 oxidation state, to activate NF-kappaB transcription factor, a pivotal regulator of inflammatory responses. Treatment of macrophages with vanadate results in the activation of both NF-kappaB and c-Jun N-terminal kinase (JNK). The activity of a recently identified cellular kinase, IkappaB kinase-beta (IKKbeta), was significantly elevated concomitant with the increased degradation of IkappaBalpha and enhanced NF-kappaB activity in cells exposed to vanadate. To determine whether the IKK pathway and JNK pathway are interconnected or bifurcate upon vanadate stimulation, cells were transfected with either a kinase inactive form of IKKbeta or a kinase inactive form of SAPK/ERK kinase 1 (SEK1). Inactive IKKbeta was able to block vanadate-induced degradation of IkappaBalpha, yet it was unable to influence the activation of JNK by vanadate. Conversely, blockage of JNK activation by transfection of a kinase-inactive form of SEK1 resulted in partially inhibition of vanadate-induced IkappaBalpha degradation. Both vanadate-induced degradation of IkappaBalpha and activation of JNK were potently inhibited by pretreatment of cells with N-acetylcysteine or dimercaprol. These results demonstrate that early activation of stress kinases or change of cellular redox states plays a key role in vanadate-induced activation of NF-kappaB and JNK.

[Determination of anions in recycle sodium formate from sodium hydrosulfite industry with single column ion chromatography]

The analysis of recycle materials from industrial waste water of sodium hydrosulfite production was made by single-column anion exchange chromatography. The recycle material was sodium formate (HCOONa) in which various anions, such as SO(3)2-, Cl-, thiosulfate, hydroxyethyl sulfonate (HOC2H4SO3-), hydroxyethyl thiosulfate (HOC2H4S2O3-), SO(4)2- and NO3- as impurities were existed simultaneously. Except hydroxyethyl sulfonate anion, all other ions can be separated by using anion exchange column Shim-pack IC-Al (4.6 mm i.d. x 100 mm) with the mixture of 1.8 mmol/L of phthalic acid and 1.35 mmol/L of Tri(hydroxymethyl) aminomethane as eluent. The flow rate of mobile phase is 1.0 mL/min. The injection volume was 20 microL. The column oven temperature was controlled at 40 degrees C. Hydroxyethyl sulfonate anion and SO(3)2- could not be separated at the above conditions, but they did not interfere the determination of HCOO-. The detection limits for HCOO-, SO(3)2-, NO3-, S2O(3)2-, HOC2H4S2O3-, Cl- and SO(4)2- were 1.0, 0.7, 1.4, 5.0, 0.7, 0.2 and 2.0 mg/L, respectively. The recoveries were between 96%-102%, and the relative standard deviations (RSD) were lower than 6.0% (n = 5) for all seven ions. This method is characterized by rapidity, sensitivity and simultaneous determination of several kinds of ions.

Urothelial hinge as a highly specialized membrane: detergent-insolubility, urohingin association, and in vitro formation

Urothelial surface is covered by numerous plaques (consisting of asymmetric unit membranes or AUM) that are interconnected by ordinary looking hinge membranes. We describe an improved method for purifying bovine urothelial plaques using 2% sarkosyl and 25 mM NaOH to remove contaminating membrane and peripheral proteins selectively. Highly purified plaques interconnected by intact hinge areas were obtained, indicating that the hinges are as detergent-insoluble as the plaques. These plaque/hinge preparations contained uroplakins, an as yet uncharacterized 18-kDa plaque-associated protein, plus an 85-kDa glycoprotein that is known to be hinge-associated in situ. Examination of the isolated, in vitro-resealed bovine AUM vesicles by quick-freeze deep-etch showed that each AUM particle consists of a 16-nm, luminally exposed "head" anchored to the lipid bilayer via a 9-mm transmembranous "tail", and that an AUM plaque can break forming several smaller plaques separated by newly formed particle-free, hinge-like areas. These data lend support to our recently proposed three-dimensional model of mouse urothelial plaques. In addition, our findings suggest that urothelial plaques are dynamic structures that can rearrange giving rise to new plaques with intervening hinges; that the entire urothelial apical surface (both plaque and hinge areas) is highly specialized; and that these two membrane domains may be equally important in fulfilling some of the urothelial functions.

[A preliminary report on two distinct tumor-suppressor regions on chromosome 1p36.2-p36.3 in human hepatocellular carcinomas]

OBJECTIVE

Both cytogenetic and molecular genetic analyses have unveiled non-random genomic alterations in the distal short arm of human chromosome 1 associated with a number of human malignancies including heptatocellular carcinoma (HCC). The aim of this investigation is to determine the precise region of deletion that may harbor the putative tumor suppressor genes in HCC.

METHODS

For the study of the loss of heterozygosity (LOH), 38 cases of hepatitis B virus (HBV) associated HCC and their corresponding non-tumor liver tissues were detected with 43 microsatellite polymorphic markers particularly focusing on 1p.

RESULTS

Twenty-eight of the 38 (74%) tumors showed LOH on at least one locus on 1p36.2-p36.3. Two distinct smallest common deleted regions (SCDRs) with different patterns of deletion were identified. The first SCDR is located on locus D1S2795 at 1p36.3, between loci D1S2145 and D1S2893. The second SCDR is located at 1p36.2, between loci D1S244 and D1S489. Both of the SCDRs have not been previously described in HCC. In addition, a region of possible homozygous deletion (HD) was also detected within the second SCDR between loci D1S1597 and D1S489 by comparative multiplex PCR. This is the first observation of a possible homozygous deletion on the distal short arm of chromosome 1 in HCC as well as in human tumors.

CONCLUSIONS

The high-resolution deletion mapping of 1p36.2-p36.3 in HCC in this study confirmed the presence of two distinct regions of deletion. Our data strongly suggest the presence of at least two tumor suppressor regions on 1p36.2-p36.3 and play an important role in the pathogenesis of HBV associated HCC. These results also provide a basis for further studies directed at cloning potential tumor suppressor genes in these regions.

[The morphological structure of classical swine fever virus and some characteristics of its multiplication]

Some characteristics of the multiplication of classical swine fever virus(CSFV) Thiverval strain were studied by means of the immunofluorescence technique. Under optimum culture conditions, the concentration of CSFV in the culture liquid multiplicated by MPK cells is ten times higher than by PK-15 cells. The half-life period of CSFV at 37 degrees C is 3 hour. The location of CSFV's replication in host cells is detected by the monoclonal antibodies of the structural protein E2 and the non-structural protein p120 of CSFV. Based on the above results, the ultrastructure of CSFV particles inside host cells was further studied using electron microscope and the changes of the ultrastructure of CSFV-infected cells are shown. The possible reasons for lower viral titre are also discussed in this paper.

[Investigating the phenomenon of total erythrocyte destruction during an in-vitro hemolysis test by roller pump]

This study sought to address the question, "will the phenomenon of 'total erythrocyte destruction' come about during a long time of in vitro hemolysis test by roller pump". One-day-old boving blood was employed in the test by Polystan pump(group A) and Cobe pump (group B). TMB method was used to measure the level of plasma-free hemoglobin. The samples of plasma-free hemoglobin were taken at the time before pumping and pumping for 4,6,8,10, 12,14 and 16 hours. The index of hemolysis was calculated according to Koller's formula. The results showed that the levels of plasma-free hemoglobin in the two groups both increased linearly during the puming of blood. The index of hemolysis was 0.2960 mg/L group A, and 0.3993 mg/L in group B; no statistically significant difference was noted between the two groups. These data indicated that no phenomenon of "total erythrocyte destruction" was observed in this hemolysis test by roller pump.

Cr(IV) causes activation of nuclear transcription factor-kappa B, DNA strand breaks and dG hydroxylation via free radical reactions

Electrophoretic mobility shift, DNA strand breakage assays and electron spin resonance (ESR) spin trapping were used to investigate the activation of nuclear transcription factor (NF)-kappa B, DNA strand breakage and 2'-deoxyguanosine hydroxylation induced by Cr(IV), as well the role of free radical reactions in these processes. Incubation of synthesized Cr(IV)-glutathione complex with cultured Jurkat cells resulted in activation of DNA binding activity of NF-kappa B. Cr(VI) is also able to induce NF-kappa B activation through Cr(V) and Cr(IV) intermediates generated during the reduction of Cr(VI) by the cells. Cr(III) did not cause observable NF-kappa B activation due to its inability to cross cell membranes. Cr(IV)-induced NF-kappa B activation is dose-dependent. Catalase inhibited the activation while superoxide dismutase enhanced it. The metal chelator, deferoxamine, and hydroxyl (.OH) radical scavengers, sodium formate and aspirin, also inhibited the NF-kappa B activation. Electrophoretic assays using lambda Hind III linear DNA showed that, in the presence of H2O2, Cr(IV) is capable of causing DNA strand breaks. Deferoxamine, sodium formate and aspirin inhibited the DNA strand breaks. HPLC measurements also show that .OH radical generated by the Cr(IV)-mediated reaction with H2O2 was capable of causing 2'-deoxyguanosine (dG) hydroxylation to generate 8-hydroxyguanosine (8-OHdG). The relative magnitude of 8-OHdG formation correlated with the generation of .OH radicals. ESR spin trapping measurements showed that reaction of Cr(IV) with H2O2 generated .OH radicals, which were inhibited by deferoxamine, sodium formate and aspirin. The results show that Cr(IV) can cause NF-kappa B activation, DNA strand breaks and dG hydroxylation through .OH radical-initiated reactions. This reactive chromium intermediate may play an important role in the mechanism of Cr(VI)-induced carcinogenesis. The results also suggest that the Cr(IV)-glutathione complex may be used as a model compound to study the role of Cr(IV) in Cr(VI) carcinogenicity.

[Simultaneous analysis of alkali metals and alkaline earth metals in Chinese herbal medicine by ion chromatography]

A simple and rapid method for the analysis of cations by using ion chromatography was developed. The results showed that the content ratio of Na+, NH4+, K+, Mg2+, Ca2+ in rhizoma chuanxiong and semen zizyphi spinosae are different. The detection limits of cations (S/N = 3) were 0.001-0.013 mg/L. The calibration curves of peak areas for all analytes were linear over two or three orders of magnitude with a regression coefficient (r2) of 0.9995-1.0000.

Solution conformation of brazzein by 1H nuclear magnetic resonance: resonance assignment and secondary structure

Brazzein is a sweet-tasting protein isolated from the fruit of the West African plant Pentadiplandra brazzeana Baillon. It is the smallest and the most water-soluble sweet protein discovered so far, it is also highly thermostable. The proton NMR study of brazzein at 600 MHz (pH 3.5, 300K) is presented. Complete sequence specific assignment of the individual backbone and sidechain proton resonances were achieved using through-bond and through-space connectivities obtained from standard two-dimensional NMR techniques. The secondary structure of brazzein contains one alpha-helix (residues 21-29), one short 3(10)-helix (residues 14-17), two strands of antiparallel beta-sheet (residues 34-39, 44-50) and probably a third strand (residues 5-7) near the N-terminus.