Polymorphisms of 5,10-methylenetetrahydrofolate reductase and risk of gastric cancer in a Chinese population: a case-control study

Low dietary folate intake has been associated with increased risk of gastric cancer. The 5,10-methylenetetrahydrofolate reductase (MTHFR) involved in folate metabolism has 2 variants, C677T and A1298C, that result in decreased MTHFR activity and lower plasma folate levels. Therefore, we hypothesized that these 2 variants play a role in gastric carcinogenesis. We tested this hypothesis in a Chinese population-based case-control study of 187 histopathologically confirmed gastric cancer cases and 166 healthy controls frequency-matched by age (+/-5 years), gender and residential area. The 677TT genotype was associated with increased risk for gastric cancer [adjusted odds ratio (OR) = 1.87, 95% confidence interval (CI) = 1.00-3.48] compared to the 677CC genotype. This association was more pronounced for gastric cardia cancer (adjusted OR = 2.47, 95% CI = 1.14-5.32). However, no evidence was found for risk associated with the MTHFR A1298C polymorphism. Our findings support the hypothesis that MTHFR C677T variants contribute to gastric carcinogenesis, particularly in gastric cardia. Larger studies incorporating dietary folate intake and serum levels are needed to confirm our findings.

Indirect electrochemical treatment of saline dyestuff wastewater

Dyestuff wastewater is always found to contain highly-concentrated sodium chloride. In many cases, biological processes are not available to dispose saline dyestuff wastewater. In this paper, both direct a nd indirect electrochemical oxidation of saline dyestuff wastewater were carried out and the accessibility of indirect electrochemical oxidation by electrochemically generated hypochlorite was investigated. It was found that the indirect electrochemical process removed COD by 87% and color by 100% in 50 minutes while the direct electrochemical process removed COD by 47% and color by 50% in 5 hours. The rate-limiting step for hypochlorite evolution at the anode was found to be diffusion-controlled. For the two processes, COD removal kinetics could be simplified as the pseudo first-order kinetics. The rate constants of COD removal were 0.038 min(-1) and 0.0018 min(-1) for the indirect and direct oxidation respectively. Current efficiency of the indirect process was I while that of the direct process was 0.16; cost efficiency of the two processes was 8,000 mg-COD (kWh)(-1) and 1,000 mg-COD (kWh)(-1) respectively. It can be concluded that the indirect electrochemical process is a promising method for the disposal of saline dyestuff wastewater.

Lack of association between the tryptophan hydroxylase gene A218C polymorphism and attention-deficit hyperactivity disorder in Chinese Han population

Previous studies have suggested that the serotonergic (5-HT) system might be involved in the development of Attention-deficit hyperactivity disorder (ADHD). ADHD is frequently characterized by aggressive and impulsive behavior, a major symptom associated with reduction in serotonergic function. The tryptophan hydroxylase (TPH) gene is a reasonable candidate for ADHD because it encodes the rate-limiting enzyme in the process of 5-HT biosynthesis. In this study, we examined the relationship between the A218C polymorphism in TPH gene and ADHD. Sixty-nine ADHD patients and their biological parents were investigated. The A218C polymorphism in intron 7 of TPH gene was detected by PCR-RFLP method. No allele or genotype concerned with this A218C polymorphism was found to be associated with ADHD when analyzed with the haplotype relative risk method. Therefore, our data indicate that the TPH gene A218C polymorphism may not be a susceptibility factor of ADHD in the Chinese Han population.

Missense polymorphism in the human carboxypeptidase E gene alters enzymatic activity

Carboxypeptidase E (CPE) is involved in the biosynthesis of peptide hormones and neurotransmitters, including insulin. One of the features of type 2 diabetes mellitus (T2DM) is an elevation in the proinsulin level and/or proinsulin/insulin molar ratio, suggesting that mutations in proinsulin processing enzymes may contribute to the development of T2DM. We scanned CPE for mutations in a collection of Ashkenazi T2DM families and identified five novel single nucleotide polymorphisms (SNPs). An SNP in the 283(rd) codon, c.847C>T, changes arginine to tryptophan (R283W). The residue Arg283 is conserved among CPE orthologs as well as most enzymatically active metallocarboxypeptidases. Of the 272 Ashkenazi T2DM pedigrees screened, we found four families segregating R283W. Within these four families, patients who inherited one copy of this variant had much earlier age of onset for T2DM. The R283W CPE protein cleaves peptide substrates with substantially lower efficiencies and is less stable at elevated temperature. In addition, the R283W CPE variant has a narrower pH optimum and is much less active at pH 6.0-6.5, indicating that the R283W CPE variant would be substantially less active than wild type CPE in the trans-Golgi network and immature secretory vesicles where the enzyme functions in vivo. To summarize, we uncovered a rare non-conservative missense mutation in CPE and demonstrated that the mutant protein has altered enzymatic properties. We predict that this mutant could cause hyperproinsulinism and diabetes in the homozygous state.

Model-based evaluation of two BNR processes--UCT and A2N

The activity of denitrifying P-accumulating bacteria (DPB) has been verified to exist in most WWTPs with biological nutrient removal (BNR). The modified UCT process has a high content of DPB. A new BNR process with a two-sludge system named A2N was especially developed to exploit denitrifying dephosphatation. With the identical inflow and effluent standards, an existing full-scale UCT-type WWTP and a designed A2N process were evaluated by simulation. The used model is based on the Delft metabolical model for bio-P removal and ASM2d model for COD and N removal. Both processes accommodate denitrifying dephosphatation, but the A2N process has a more stable performance in N removal. Although excess sludge is increased by 6%, the A2N process leads to savings of 35, 85 and 30% in aeration energy, mixed liquor internal recirculation and land occupation respectively, as compared to the UCT process. Low temperature has a negative effect on growth of poly-P bacteria, which becomes to especially appear in the A2N process.

A novel method for beat-to-beat detection of ventricular late potentials

A novel method for beat-to-beat detection of ventricular late potentials (VLP) from high-resolution electrocardiograms (ECGs) is presented. ECG signals from the X lead are first filtered using a bandpass filter, and then a time-sequence adaptive filter, to improve its signal-to-noise ratio. Eight features are extracted using wavelet transform, from the VLP time-frequency distribution of the filtered ECG signals, and used as inputs of specially designed artificial neural network for VLP recognition. The artificial neural network was trained and tested using clinical data, respectively. The results show that the presented method can detect beat-to-beat-based VLP with sensitivity of 80% and specificity of 77%, and the detection accuracy is 78%.

[Biodegradation of reactive turquoise blue]

In this study, the anaerobic degradation and the aerobic degradation of a kind of reactive dye--Reactive Turquoise Blue(RTB) were compared. The results proved that anaerobic sludge could only decompose RTB in the presence of glucose while aerobic sludge decomposed RTB with or without the presence of glucose (RTB of 20 mg/L was reduced by 37.4% through 24 hours' aerobic treatment with RTB as sole carbon source). The enhancement of glucose concentration was beneficial for both anaerobic and aerobic degradation of RTB: the anaerobic and the aerobic removal efficiencies were respectively 81.5% and 73.6% with RTB of 20 mg/L and glucose of 1200 mg/L. In the influent RTB concentration also had influence on the activity of anaerobic and aerobic microorganisms. When glucose concentration was 800 mg/L or 1200 mg/L and RTB concentration was 20 mg/L to 100 mg/L, anaerobic removal efficiency of RTB was higher than aerobic removal efficiency by 4.9%-27.2%, which meant that anaerobic bacteria is more powerful than aerobic bacteria in terms of RTB removal.

[Kinetic study on photocatalytic degradation of p-chlorobenzoate at different light intensities]

Kinetics of photocatalytic degradation were investigated at different light intensities using para-chlorobenzoate as a model pollutant. It was experimentally found that the Langmuir-Hinshelwood model could satisfactorily describe all the kinetic processes. However, the two crucial parameters involved in the L-H model were dependent of the incident light intensity. With elevated light intensity, the rate constant, kr, increased whereas the apparent adsorption constant, Ks, decreased. Grossly, both kr and Ks-1 were correlated with the light intensity in a power law. The experimental discovery implies that the photonic efficiency would be much deteriorated with increased radiation intensity although the reaction rate can be enhanced. Applying mild light intensity might be one of the critical strategies in photocatalytic reactor design to improve the photonic efficiency.

The sorption behavior of complex pollution system composed of aldicarb and surfactant--SDBS

The behavior of complex pollution system in soil composed of aldicarb, a carbamate pesticide, and sodium dodecylbenzenesulfonate (SDBS), an anionic surfactant, was studied by the experiment of shaking sorption balance. The range of concentration of aldicarb and SDBS was 0.4-5.0 and 1-1000 mg/kg of dried soil, respectively. Linear sorption isotherm was well fitted for these two chemicals. SDBS can decrease the sorption of aldicarb in soil remarkably. While the concentration of SDBS increased from 0 to 1000 mg/kg, the linear sorption coefficient can be decreased by 50%. But aldicarb showed no effect on the sorption of SDBS in experiment. In addition the mechanism of the effect of SDBS on sorption of aldicarb was discussed.

[Study of susceptibility loci located within Xp11 in attention deficit hyperactivity disorder]

OBJECTIVE

To detect the genetic relationship between monoamine oxidase(MAO) A type gene and attention deficit hyperactivity disorder(ADHD) in Chinese.

METHODS

The haplotype-based haplotype relative risk(HHRR) and the transmission disequilibrium test(TDT) methods were used to analyze the genetic association and linkage in 60 ADHD children and their parents.

RESULTS

In this sample were found significant association (chi(2)=4.90, P<0.05) and linkage (chi(2)=4.84, P<0.05) between the MAOCA 114bp allele and DSM-III-R-diagnosed ADHD in trios composed of father, mother and affected offspring.

CONCLUSION

The above results suggested that ADHD was associated and in linkage with MAO A gene, and the susceptibility loci might reside in chromosome Xp11 for ADHD.

Cr (VI) increases tyrosine phosphorylation through reactive oxygen species-mediated reactions

While Cr (VI)-containing compounds are well established carcinogens, the mechanisms of their action remain to be investigated. In this study we show that Cr (VI) causes increased tyrosine phosphorylation in human lung epithelial A549 cells in a time-dependent manner. N-acetyl-cysteine (NAC), a general antioxidant, inhibited Cr (VI)-induced tyrosine phosphorylation. Catalase, a scavenger of H2O2, sodium formate and aspirin, scavengers of hydroxyl radical (*OH), also inhibited the increased tyrosine phosphorylation induced by Cr (VI). SOD, an inhibitor of superoxide radical (O2*-), caused less inhibition. ESR study shows that incubation of Cr (VI) with the A549 cells generates *OH radical. The generation of radical was decreased by addition of catalase and sodium formate, while SOD did not have any inhibitory effect. Oxygen consumption measurements show that addition of Cr (VI) to A549 cells resulted in enhanced molecular oxygen consumption. These results indicate that Cr (VI) can induce an increase in tyrosine phosphorylation. H2O2 and *OH radicals generated during the process are responsible for the increased tyrosine phosphorylation induced by Cr (VI).

Severe hepatitis treated with an artificial liver support system

We designed an artificial liver support system (ALSS) including plasma exchange, charcoal hemoperfusion, plasma bilirubin absorption, charcoal plasma perfusion, hemofiltration and hemodialysis. We chose different methods or their combinations according to the patient's conditions. We investigated the effect of ALSS in 154 patients with severe hepatitis, 72 of whom survived. All data were analyzed by SPSS. The effectiveness of ALSS treatment was compared at different stages (i.e. early, middle and end stages). After each ALSS treatment, the liver function of these patients greatly improved, serum endotoxin and HBV-DNA concentrations were significantly decreased, and the serum concentration of aromatic amino acids (AAA) such as methionine decreased while BCAA/AAA ratio increased. Patients treated with ALSS in the early or middle stages of disease had much higher survival rates than patients in the end stage of disease. Thus, we concluded that ALSS is a reliable therapy for advanced liver diseases and treatment in early or middle stages is appropriate.

Computational fluid dynamics performance prediction for the hydrodynamic bearings of the ventrassist rotary blood pump

Finite-volume computations are described for laminar flow in the hydrodynamic bearings supporting 2 different versions of the impeller of the VentrAssist rotary pump. Pressure boundary conditions are taken from prior computations of turbulent flow in the whole pump with frictionless sliding of the impeller on the inside of the pump body. By investigating various impeller positions, the true ride height is determined. Net lift and combined drag from all 8 bearings of the 4-bladed impeller are compared with predictions based on 2-D theory. The computations also reveal the extent of net force and moment acting to move the impeller away from its nominal axis of rotation.

Anti-Sm B cell differentiation in Ig transgenic MRL/Mp-lpr/lpr mice: altered differentiation and an accelerated response

To determine the regulation of B cells specific for the ribonucleoprotein Sm, a target of the immune system in human and mouse lupus, we have generated mice carrying an anti-Sm H chain transgene (2-12H). Anti-Sm B cells in nonautoimmune 2-12H-transgenic (Tg) mice are functional, but, in the absence of immunization, circulating anti-Sm Ab levels are not different from those of non-Tg mice. In this report, we compare the regulation of anti-Sm B cells in nonautoimmune and autoimmune MRL/Mp-lpr/lpr (MRL/lpr) and bcl-2-22-Tg mice. Activation markers are elevated on splenic and peritoneal anti-Sm B cells of both nonautoimmune and autoimmune genetic backgrounds indicating Ag encounter. Although tolerance to Sm is maintained in 2-12H/bcl-2-22-Tg mice, it is lost in 2-12H-Tg MRL/lpr mice, as the transgene accelerates and increases the prevalence of the anti-Sm response. The 2-12H-Tg MRL/lpr mice have transitional anti-Sm B cells in the spleen similar to nonautoimmune mice. However, in contrast to nonautoimmune mice, there are few if any peritoneal anti-Sm B-1 cells. These data suggest that a defect in B-1 differentiation may be a factor in the loss of tolerance to Sm and provide insight into the low prevalence of the anti-Sm response in lupus.

Complete genome sequence of an M1 strain of Streptococcus pyogenes

The 1,852,442-bp sequence of an M1 strain of Streptococcus pyogenes, a Gram-positive pathogen, has been determined and contains 1,752 predicted protein-encoding genes. Approximately one-third of these genes have no identifiable function, with the remainder falling into previously characterized categories of known microbial function. Consistent with the observation that S. pyogenes is responsible for a wider variety of human disease than any other bacterial species, more than 40 putative virulence-associated genes have been identified. Additional genes have been identified that encode proteins likely associated with microbial "molecular mimicry" of host characteristics and involved in rheumatic fever or acute glomerulonephritis. The complete or partial sequence of four different bacteriophage genomes is also present, with each containing genes for one or more previously undiscovered superantigen-like proteins. These prophage-associated genes encode at least six potential virulence factors, emphasizing the importance of bacteriophages in horizontal gene transfer and a possible mechanism for generating new strains with increased pathogenic potential.

Blockade of CD40-CD154 costimulatory pathway promotes survival of allogeneic corneal transplants

PURPOSE

To determine the effect of systemic anti-CD154 monoclonal antibody on the survival of orthotopic murine corneal transplants.

METHODS

BALB/c mice were used as recipients of syngeneic, multiple minor histocompatability (H)-disparate, or major histocompatibility complex MHC-mismatched corneal transplants. Recipient beds were either avascular (normal risk) or neovascularized (high risk). Mice were randomized to receive either anti-CD154 antibody or control immunoglobulin by intraperitoneal injection at surgery and once weekly after surgery. After orthotopic corneal transplantation, all grafts were evaluated for signs of rejection by slit lamp biomicroscopy over 8 weeks. The high-risk transplants were continuously observed until week 18 after the therapy was discontinued at week 8. Allospecific delayed-type hypersensitivity (DTH) was evaluated after transplantation in high-risk graft recipients. Frequency of interferon (IFN)-gamma-secreting T cells in the hosts was measured by enzyme-linked immunospot (ELISPOT) assay.

RESULTS

In normal-risk transplantation, the 8-week survival rate improved from 25% in control mice to 88% in anti-CD154-treated hosts of minor H-disparate grafts (P = 0.0087) and from 78% in control mice to 100% in anti-CD154-treated recipients of MHC-mismatched transplants (P = 0.177). Of particular significance, in high-risk transplantation, anti-CD154 therapy dramatically enhanced the survival of both minor H- and MHC-disparate corneal transplants to 100% (P = 0.0001) and 92% (P = 0.0002), respectively. In addition, the anti-CD154-treated mice did not exhibit allospecific immunity. However, termination of anti-CD154 led to some loss in graft survival, especially among high-risk minor H-disparate grafts. The frequency of IFN-gamma-producing T cells was significantly reduced in anti-CD154-treated hosts.

CONCLUSIONS

Continuous suppression of the CD40-CD154 costimulatory pathway promotes the acceptance of corneal transplants, regardless of the degree of allodisparity or preoperative risk. The beneficial effect of anti-CD154 treatment may be due in part to inhibition of Th1-mediated responses.

Bis(2,2-bipyridine-N,N')tetra-mu-chloro-tetracopper(I)

A novel centrosymmetric chair-like dimer, bis(2,2'-bipyridine)-1kappa(2)N,N';3kappa(2)N,N'-tetra-mu-chloro-1:2kappa(2)Cl;2:3kappa(2)Cl;3:4kappa(2)Cl;1:4kappa(2)Cl-tetracopper(I), [Cu(4)Cl(4)(C(10)H(8)N(2))(2)], has been solvothermally synthesized and structurally characterized. The complex self-assembles into a three-dimensional network via C-H.Cl hydrogen bonds, pi-pi stacking and weak Cu.Cl electrostatic interactions.

Expression and self-assembly in baculovirus of porcine enteric calicivirus capsids into virus-like particles and their use in an enzyme-linked immunosorbent assay for antibody detection in swine

Porcine enteric calicivirus (PEC) causes diarrhea and intestinal lesions in pigs. PEC strain Cowden grows to low to moderate titers in cell culture but only with the addition of intestinal contents from uninfected gnotobiotic pigs (W. T. Flynn and L. J. Saif, J. Clin. Microbiol. 26:206--212, 1988; A. V. Parwani, W. T. Flynn, K. L. Gadfield, and L. J. Saif, Arch. Virol. 120:115--122, 1991). Cloning and sequence analysis of the PEC Cowden full-length genome revealed that it is most closely related genetically to the human Sapporo-like viruses. In this study, the complete PEC capsid gene was subcloned into the plasmid pBlueBac4.5 and the recombinant baculoviruses were identified by plaque assay and PCR. The PEC capsid protein was expressed in insect (Sf9) cells inoculated with the recombinant baculoviruses, and the recombinant capsid proteins self- assembled into virus-like particles (VLPs) that were released into the cell supernatant and purified by CsCl gradient centrifugation. The PEC VLPs had the same molecular mass (58 kDa) as the native virus capsid and reacted with pig hyperimmune and convalescent-phase sera to PEC Cowden in enzyme-linked immunosorbent assay (ELISA) and Western blotting. The PEC capsid VLPs were morphologically and antigenically similar to the native virus by immune electron microscopy. High titers (1:102,400 to 204,800) of PEC-specific antibodies were induced in guinea pigs inoculated with PEC VLPs, suggesting that the VLPs could be useful for future candidate PEC vaccines. A fixed-cell ELISA and VLP ELISA were developed to detect PEC serum antibodies in pigs. For the fixed-cell ELISA, Sf9 cells were infected with recombinant baculoviruses expressing PEC capsids, followed by cell fixation with formalin. For the VLP ELISA, the VLPs were used for the coating antigen. Our data indicate that both tests were rapid, specific, and reproducible and might be used for large-scale serological investigations of PEC antibodies in swine.

[Extinction characteristics of TiO2 suspension for different band ultraviolet radiation]

This study focused on the global absorption characteristics of UVA, UVB and UVC radiation in the suspension of titanium-pollutant solution using 4-CBA-Na as a model pollutant. The result showed that the attenuation of ultraviolet in the suspensions conformed to Beer's Law, light intensity negative-exponentially attenuating with the optic path. The extinction coefficient increased with the titanium dosage by a quadratic polynomial law, which may be approximated by a linear function at lower dosage. The sum of the respective UVC or UVB extinction coefficient in pollutant solution and titanium-water suspension was found to approach the measured value in Titanium-Pollutant suspension. Larger extinction coefficient was observed for shorter UV wavelength, implying higher energy efficiency with UVC as ultraviolet source.

Lupus-specific antiribonucleoprotein B cell tolerance in nonautoimmune mice is maintained by differentiation to B-1 and governed by B cell receptor signaling thresholds

Systemic lupus erythematosus is an autoimmune disease characterized by the presence of autoantibodies. One of the unique targets of the immune system in systemic lupus erythematosus is Sm, a ribonucleoprotein present in all cells. To understand the regulation of B cells specific to the Sm Ag in normal mice, we have generated an Ig H chain transgenic mouse (2-12H Tg). 2-12H Tg mice produce B cells specific for the Sm that remain tolerant due to ignorance. We demonstrate here that anti-Sm B cells of 2-12H Tg mice can differentiate into Sm-specific peritoneal B-1 cells that remain tolerant. Differentiation to B-1 and tolerance are governed by the strength of B cell receptor signaling, since manipulations of the B cell receptor coreceptors CD19 and CD22 affect anti-Sm B cell differentiation and autoantibody production. These results suggest a differentiation scheme in which peripheral ignorance to Sm is maintained in mice by the differentiation of anti-Sm B cells to B-1 cells that have increased activation thresholds.

[Quinoline removal in fluidized-bed bioreactor using immobilized cells]

Burkholderia pickettii, capable of using quinoline as sole source of carbon, nitrogen and energy, was immobilized by an innovative PVA-H3BO3-gauze method. A fluidized-bed bioreactor, in which immobilized cells were added, was constructed to degrade quinoline in wastewater. When the initial concentrations of quinoline were 100, 350 and 500 mg/L, the bioreactor can remove it completely within 2.5, 6 and 12 hours respectively. A series of zero-order reaction equations were proposed to describe quinoline biodegradation process in this bioreactor kinetically. In continuous flow experiments, the performance of the bioreactor was investigated at different HRT (dilution rate) for different quinoline concentrations in wastewater and the tolerance against shock loading was determined by increasing quinoline concentration from 100 to 300 to 500 mg/L at HRT 4 hours.

[Study of the adsorption properties in chromatographic separation of the citric acid]

A new method studying the change of thermodynamic properties at different temperatures to screen suitable stationary phases for chromatographic separation of the citric acid (CA) on an analytical column has been developed. The applied method is mainly based on using CA with a series of solute concentrations (0 g/L-250 g/L) as mobile phase to seriously overpass the unloaded stationary phase to find the breakthrough curves of CA. The adsorption isotherms were calculated from the retention times of breakthrough curve. The bed porosity of column was calculated from the elution time of a peak of the blue dextran as non-adsorbed tracer. The stationary phase, which has been selected through this method, for the separation of CA from fermentation broth, showed a very high adsorption capacity for CA, even under very low concentrations, so it can even be used in the separation and purification process of minute amounts of CA. The separation effect of this stationary phase for citric acid can be greatly enhanced through the technique of change of temperature. This new separation process can shorten the old process path, improve the yield of finished products more than 10%, and reduce the cost more than 10%. At the same time, the pollution of the production of citric acid can be reduced. It turned out that this method will play an important role in the synthesis of stationary phase for the separation of citric acid and the study of its structure.

Status of persistent organic pollutants in the sediment from several estuaries in China

Sediment samples from three estuaries on the east coast of China were analyzed for persistent organic pollutants. Total PCB, PAH, and DDT concentrations in the sediments from Minjiang, Jiulongjiang, and Zhujiang estuaries ranged from 2 to 14 ng/g, 400 to 1500 ng/g, and 6 to 73 ng/g, respectively, in the sediments from these estuaries. The sources of PAH contamination were inferred from PAH compositions, with pyrogenic PAHs being the dominant source for Minjiang Estuary and petroleum related PAHs being the primary contributors to Jiulongjiang and Zhujiang estuaries. The high concentrations of DDT in the sediments from these estuaries were likely the result of widespread use of DDT in China in the 1960s and 1970s. Butyltin compounds were detected in the sediment from Jiulongjiang Estuary and Victoria Harbor, Hong Kong. Presence of butyltin compounds probably result from the shipping activities in these estuaries. Butyltin compounds were not detected in the sediments from Minjiang and Zhujiang estuaries. Contaminant concentrations were generally below levels expected to affect benthic organisms with the exception of DDTs.