Comparative acute and combinative toxicity of aflatoxin B1 and fumonisin B1 in animals and human cells

Aflatoxin B(1) (AFB(1)) and fumonisin B(1) (FB(1)) are important food-borne mycotoxins. The co-contamination of food stuffs with these two mycotoxins is well known and has been possibly implicated in the development of human hepatocellular carcinoma in high risk regions around the world. In this study the acute and combinative toxicity of AFB(1) and FB(1) were tested in F-344 rats, mosquitofish (Gambusia affinis), immortalized human hepatoma cells (HepG2) and human bronchial epithelial cells (BEAS-2B). Preliminary experiments were conducted in order to assess the acute toxicity and obtain LD(50), LC(50) and IC(50) values for individual toxins in each model, respectively. This was followed by testing combinations of AFB(1) and FB(1) to obtain LD(50), LC(50) and IC(50) values for the combination in each model. All models demonstrated a significant dose response in relation to toxin treatment. The potency of the mixture was gauged through the determination of the interaction index metric. Results of this study demonstrate that these two toxins interacted to produce alterations in the toxic responses with a strong additive interaction noted in the cases of F344 rats and mosquitofish. It can be gathered that this combination may pose a significant threat to public health and further research needs to be completed addressing alterations in metabolism and detoxification that may influence the toxic manifestations in combination. These results will provide foundational knowledge for future studies on long-term combinative toxic and health effects of these mycotoxins.

Leisure activity and risk of cognitive impairment: The Chongqing aging study

The authors followed 5,437 people aged 55 years and older with normal baseline Mini-Mental State Examination score annually for 5 years. The mean incidence of cognitive impairment was 2.3% per year. Cognitive activities in both the individual item (playing board games and reading) and the composite measure were associated with the reduced risk of cognitive impairment, while watching television was associated with an increased risk of cognitive impairment.

NAD-sensitive hydrogel for the release of macromolecules

A hydrogel membrane containing immobilized ligands and receptors was synthesized and investigated for the controlled diffusion of test proteins (cytochrome C and hemoglobin). Both Cibacron blue (ligand) and lysozyme (receptor) were covalently linked to dextran molecules that were subsequently crosslinked to form a gel. The resulting stable hydrogels contained both covalent and affinity crosslinks such that their intrinsic porosities were sensitive to competitive displacers of the affinity interaction between lysozyme and Cibacron blue. Transport experiments in a twin chamber diffusion cell showed that as NAD was added to the donor side, the dissociation of the binding sites between the Cibacron blue and the lysozyme led to an increase in protein diffusion through the hydrogel. The results showed that addition of NAD caused a saturable concentration-dependent increase in the transport of both cytochrome C and hemoglobin. This effect was shown to be both specific and reversible.

Sustained Homocysteine-Lowering Effect over Time of Folic Acid-Based Multivitamin Therapy in Stroke Patients despite Increasing Folate Status in the Population

BACKGROUND AND AIMS

It is uncertain what impact increasing voluntary folate fortification may be having on the statistical power of randomized trials testing the homocysteine hypothesis of atherothrombosis. The objective of this study was to determine whether there has been a change in folate status between 1998 and 2002 in stroke patients randomized into the VITAmins TO Prevent Stroke (VITATOPS) Study at a single center in Perth, Australia, and what impact this may have had on the magnitude of the homocysteine-lowering effect achieved over time with folic acid-based multivitamin therapy.

METHODS

We conducted a randomized, double-blind, placebo-controlled study involving 285 patients with stroke or transient ischemic attack who were recruited between 1998 and 2002 and randomized to long-term folic acid 2.0 mg/day, pyridoxine 25 mg/day and cobalamin 0.5 mg/day (active VITATOPS medication) or placebo. Fasting plasma total homocysteine, red cell folate, serum cobalamin and serum pyridoxine levels were measured at baseline and 6 months, and the change in blood levels over 4 time quartiles and differences in levels between the two randomized treatments were examined.

RESULTS

Between 1998 and 2002, there was a significant rise in baseline mean red cell folate levels over 4 time quartiles among the entire stroke cohort (723.3, 780.1, 922.6 and 1,023.7 nmol/l in the first, second, third and fourth quartiles, respectively; p < 0.0001), but this was not associated with a spontaneous reduction in mean baseline total homocysteine levels during the same time period (12.7, 14.3, 12.1 and 12.8 micromol/l in the first, second, third and fourth quartiles, respectively; p = 0.55). The homocysteine-lowering effect of the active VITATOPS trial medication at 6 months after randomization also did not change significantly between 1998 and 2002 (difference between randomized groups: -4.1, -4.1, -3.1 and -3.6 micromol/l in the first, second, third and fourth quartiles, respectively; p = 0.56).

CONCLUSIONS

The homocysteine-lowering effect of the active VITATOPS trial medication has not attenuated significantly in the past 5 years despite increasing voluntary fortification of foods with folic acid as reflected by a progressive rise in baseline folate status. These data suggest that in the continuing absence of a program of mandatory folate fortification of food in populations served by centers participating in the VITATOPS trial, the study will remain adequately powered to test the homocysteine-lowering hypothesis for which it was designed.

ASCIA guidelines for prevention of food anaphylactic reactions in schools, preschools and child-care centres

These guidelines have been developed by the anaphylaxis working party of the Australasian Society of Clinical Immunology and Allergy to provide advice for minimizing the risk of food-induced anaphylaxis in schools, preschools and child-care centres. The guidelines outline four steps for the prevention of food anaphylactic reactions in children at risk and food policy measures specific to school age and preschool age children.

Expression of vip1/vip2 genes in Escherichia coli and Bacillus thuringiensis and the analysis of their signal peptides

AIMS

To determine the expression time courses and high expression level of Vip2A(c) and Vip1A(c) in Bacillus thuringiensis, and survey their insecticidal toxicity and insecticidal spectrum.

METHODS AND RESULTS

A kind of new vegetative insecticidal toxin genes encoded by a single operon from B. thuringiensis had been cloned and sequenced. The individual genes, 5-terminus truncated genes and the operon were respectively expressed in Escherichia coli. Only N-terminus deleted Vip2A(c) and Vip1A(c) proteins could be purified by Ni-NTA agarose, while others were processed and their N-terminal signal peptides were cleaved. The individual genes and the operon were also expressed in B. thuringiensis. Both proteins were mostly secreted into the cell supernatants. The expression level of Vip1A(c) was influenced because of the interruption of vip2A(c) gene on the operon. Bioassays showed that neither separate protein nor both performed any toxicity against tested lepidopteran and coleopteran insects.

CONCLUSIONS

Vip2A(c) and Vip1A(c) have similar secretion mechanism in E. coli and B. thuringiensis. Vip1A(c) remained its high expression level only when being expressed with vip2A(c) gene as an operon in B. thuringiensis.

SIGNIFICANCE AND IMPACT OF THE STUDY

Expression of vip2A(c) and vip1A(c) genes in E. coli and B. thuringiensis were investigated. This would help to make clear the secretion mechanism of VIP proteins and study the function of ADP-ribosyltransferase Vip2.

Protective Effects of Mutant Ubiquitin in Transgenic Mice

The K48R mutant ubiquitin can exert profound in vivo protective effects against a variety of insults, including agents of direct clinical relevance. The manipulation of the ubiquitin/proteasome pathway has enormous potential for clinical benefit, and it is not unreasonable to expect that such benefits will include diseases of aging.

Disparate effects of relaxin and TGFbeta1: relaxin increases, but TGFbeta1 inhibits, the relaxin receptor and the production of IGFBP-1 in human endometrial stromal/decidual cells

BACKGROUND

The purpose of this study was to determine the effect of progestin, relaxin (RLX) and transforming growth factor beta1 (TGFbeta1) on the content of relaxin receptor (LGR7) mRNA. The effect of RLX on insulin-like growth factor binding protein-1 (IGFBP-1) production was determined to evaluate the biological function of RLX/receptor in human endometrial cells.

METHODS AND RESULTS

The levels of LGR7 mRNA and the effect of hormones were determined by real-time PCR in endometrial cells. LGR7 mRNA was found to be relatively abundant in endometrial glands and decidual cells and much less in endometrial stromal cells. In stromal cells, medroxyprogesterone acetate (MPA), or MPA plus RLX, significantly increased the LGR7 mRNA and RLX alone had little effect. In decidual cells, RLX increased LGR7 mRNA in a dose- and time-dependent fashion. TGFbeta1 reduced the LGR7 mRNA. In stromal cells, MPA alone caused a slight increase (2-4-fold) of the production rate of IGFBP-1 whereas MPA plus RLX synergistically increased (>40-fold) the IGFBP-1 production. In decidual cells in which the basal production rate was already approximately 50-fold higher than in stromal cells, RLX alone caused an additional increase (>30-fold) on the production rate. TGFbeta1 inhibited the IGFBP-1 production.

CONCLUSION

The present study showed that in undifferentiated endometrial stromal cells, progestin increases the RLX receptor content to enhance the effect of RLX on the target gene (IGFBP-1). In decidual cells, RLX alone up-regulates its receptor, resulting in a large scale induction of IGFBP-1. TGFbeta1 has an inhibitory effect on LGR7 and IGFBP-1.

Feasibility of a bioadhesive drug delivery system targeted to oesophageal tissue

This contribution examines the feasibility of utilising an oesophageal-adhesive alginate layer to support model drug particles. Such a bioadhesive system offers the prospect of local drug delivery to the oesophagus, which in turn has applications in the treatment of conditions including gastro-oesophageal reflux disease and oesophageal cancer. Surface-modified (amine, carboxylate and sulfate) as well as neutral fluorescent beads were investigated as model drug particles. A fluorescence assay technique was utilised to quantify the extent and duration of adhesion of a fixed dose of these particles to excised porcine oesophageal tissue. Retention of the particles was investigated both from aqueous systems and within an adhesive alginate solution. After 30 min significantly higher adhesion of neutral beads was recorded from the alginate solution as compared to the aqueous suspension (n = 6, P < 0.05). The beads that possessed a negative charge showed significantly greater retention within the alginate carrier (n = 6, P < 0.05). However, the amine-modified beads showed retention profiles that were similar both within the alginate carrier and within the aqueous suspension (n = 6, P > 0.05).

Association between apolipoprotein CI HpaI polymorphism and sporadic Alzheimer's disease in Chinese

OBJECTIVE

To investigate into the relationship of apolipoprotein CI (ApoCI) polymorphism with sporadic Alzheimer's disease (AD) in Chinese.

SUBJECTS AND METHODS

A total of 257 AD patients and 242 age-matched elderly individuals were genotyped for the ApoCI HpaI and apolipoprotein E (ApoE) HhaI polymorphisms.

RESULTS

The ApoCI A allele was associated with AD of moderate to severe dementia when patients were divided into two subgroups according to Clinical Dementia Rating scale, and the AA genotype was strongly associated with moderate to severe AD in ApoE epsilon4 allele carriers [odds ratio (OR) = 8.19, 95% confidential interval: 1.28-52.30, after adjusting for age and gender by logistic regression analysis], although in total no significant differences of allele or genotype frequency between patients and controls were found.

CONCLUSION

The present study partially confirmed the previous findings, suggesting that the ApoCI A allele might contribute to the susceptibility to moderate to severe sporadic AD in Chinese.

Comparison of the expression of Bacillus thuringiensis full-length and N-terminally truncated vip3A gene in Escherichia coli

AIMS

Studies were performed to demonstrate the function of the putative signal peptide of Vip3A proteins in Escherichia coli.

METHODS AND RESULTS

The full-length vip3A-S184 gene was isolated from a soil-isolated Bacillus thuringiensis, and the vip3AdeltaN was constructed by deleting 81 nucleotides at the 5'-terminus of vip3A-S184. Both were transformed and expressed in E. coli. About 19.2% of Vip3A-S184 proteins secreted soluble proteins and others formed inclusion bodies in the periplasmic space. In contrast, the Vip3AdeltaN was insoluble and formed inclusion bodies in the cytoplasm. Bioassay indicated that Vip3A-S184 showed different toxicity against Spodoptera exigua, Helicoverpa armigera and S. litura, but Vip3AdeltaN showed no toxicity to either of them because of the deletion of the first 27 amino acids at the N-terminus.

CONCLUSIONS

The results suggest that the deleted N-terminal sequences were essential for the secretion of Vip3A-S184 protein in E. coli and might be required for toxicity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The function of the putative signal peptide of Vip3A protein in E. coli was investigated. These would be helpful to make clear the unknown secretion pathway of Vip3A protein in B. thuringiensis and determine the receptor-binding domain or toxic fragment of Vip3A-S184 protein.

Design of double-pass discrete Raman amplifier and the impairments induced by Rayleigh backscattering

We report on the investigation of discrete Raman fiber amplifier in double-pass configuration based on the dispersion-compensated fiber and high reflection FBG. We proved in simulation and experiments that the double-pass configuration requires nearly 50% less pump power and the same fiber length to provide the same Raman gain and double-dispersion-compensation performance compared to the typical counter-pumped Raman amplifier. We also analyzed the equivalent noise figure (NF) and the Rayleigh backscattering impairments. The theoretical results shown that the impact of multipath interference (MPI) noise is the dominating limitation factor of this system operated at very high Raman gain region.

Prevalence and specificity of clinically significant red cell alloantibodies in Chinese women during pregnancy--a review of cases from 1997 to 2001

Guidelines for the prevention and management of red cell alloantibodies during pregnancy, related to anti-D in particular, are well established in Caucasian populations. However, because of the racial difference of the blood group distribution, applicability to Chinese is unknown as a result of insufficient data on the prevalence and their outcome. In a retrospective review of 28,303 (21,327 Chinese) antenatal attendances from 1997 to 2001, 213 (0.79%) women were found to have a total of 230 irregular antibodies. About 137 (0.64%) were ethnic Chinese, and a total of 160 irregular antibodies were identified in their blood samples. About 58 of these Chinese women (0.27%) were found to have 66 clinically significant antibodies. There was only one case of anti-D detected in an Rh(D)-negative subject. Our study shows the overall prevalence of clinically significant antibodies in Chinese women, which was not different from that of the Western population. However, the specificities of the antibodies differ with the commonest antibodies encountered; these being anti-Mi (57.6%), anti-E (19.7%), anti-S (10.6%) and anti-c (7.6%). Neonatal jaundice was observed in 37 babies and 10 of them required phototherapy. The findings support the previous recommendation that routine antenatal antibody screening for Chinese women may not be worthwhile except in Rh(D)-negative subjects or those with an antecedent history of haemolytic disease of the newborn (HDN). The relative high incidence of anti-Mi in the present study and the local population, in general, may warrant a large-scale prospective study of pregnancy outcome in these subjects, especially in the light of the previous case reports of HDN because of anti-Mi.

A reversible hydrogel membrane for controlling the delivery of macromolecules

Glucose-sensitive hydrogel membranes have been synthesized and characterized for their rate-of-delivery of macromolecules. The mechanism for changing this rate is based on variable displacement of the affinity interaction between dextran and concanavalin A (con A). Our main objective was to characterize the diffusion of model proteins (insulin, lysozyme, and BSA) through the membrane, in response to changes in environmental glucose concentrations. Membranes were constructed from crosslinked dextrans to which con A was coupled via a spacer arm. Changes in the porosity of the resulting hydrogel in the presence of glucose led to changes in the diffusion rate observed for a range of proteins. Gels of specified thickness were cast around to nylon gauze support (pore size, 0.1 mm) to improve mechanical strength. Diffusion of proteins through the gel membrane was determined using a twin-chamber diffusion cell with the concentrations being continuously monitored using a UV-spectrophotometer. Changes in the transport properties of the membranes in response to glucose were explored and it was found that, while 0.1M D-glucose caused a substantial, but saturateable, increase in the rates of diffusion of both insulin and lysozyme, controls using glycerol or L-glucose (0.1M) had no significant effect. Sequential addition and removal of external glucose in a stepwise manner showed that permeability changes were reversible. As expected, diffusion rates were inversely proportional to membrane thickness. A maximum increase in permeability was observed at pH 7.4 and at 37 degrees C. The results demonstrate that this hydrogel membrane functions as a smart material allowing control of solute delivery in response to specific changes in its external environment.

Recombinant adenovirus encoding the HA gene from swine H3N2 influenza virus partially protects mice from challenge with heterologous virus: A/HK/1/68 (H3N2)

Immunization with recombinant adenoviral vaccine that induces potent immunity has been applied to many infectious diseases. We report here developing a recombinant adenoviral vaccine encoding the HA gene from swine H3N2 influenza virus (SIV). Two replication-defective recombinant adenoviruses were generated: (1) rAd-HA: recombinant adenovirus encoding the HA gene from swine H3N2 influenza virus, and (2) rAd-vector: a control recombinant adenovirus containing adenovirus and transfer plasmids without a foreign HA gene. Mice given rAd-HA developed high titers of neutralizing and hemagglutination inhibition antibodies to SIV in comparison to mice inoculated with rAd-vector or PBS as early as 2 weeks after immunization, and these antibodies were substantially increased in the mice given rAd-HA within the next 3 weeks following the first dose. However, these antibodies were not able to neutralize the virus, A/HK/68 (H3N2), used for challenge. Nonetheless mice immunized with one or two doses of rAd-HA were protected from lethal challenge with heterologous virus, A/HK/1/68 (H3N2). A statistically significant ( P < 0.03) difference between survival rates of rAd-HA mice vs. rAd-vector or PBS mice was observed.

Sex-related interactive effect of smoking and household pets on asthma incidence

The authors examined the interactive effect of smoking and pets at home on the incidence of asthma and the difference between sexes. The longitudinal data from the first two cycles of the National Population Health Survey, conducted in Canada, were used. A total of 12,636 subjects who reported no asthma at baseline were included in the analysis. The 2-yr cumulative incidence of asthma was higher in females than in males. Female sex and household pets demonstrated a significant interaction in the development of asthma. After adjustment for age, immigration and history of allergy, the odds ratio for smoking in relation to the asthma incidence was 2.50 (95% confidence interval: 1.24-5.05) for females who had pets at home and close to unity for those who had no pets. The incidence of asthma was not associated with smoking status and household pets in males. These results indicate that smoking, having pets at home and other environmental factors can partly explain asthma morbidity among female Canadians.

High resolution chromosome 3p, 8p, 9q and 22q allelotyping analysis in the pathogenesis of gallbladder carcinoma

Our recent genome-wide allelotyping analysis of gallbladder carcinoma identified 3p, 8p, 9q and 22q as chromosomal regions with frequent loss of heterozygosity. The present study was undertaken to more precisely identify the presence and location of regions of frequent allele loss involving those chromosomes in gallbladder carcinoma. Microdissected tissue from 24 gallbladder carcinoma were analysed for PCR-based loss of heterozygosity using 81 microsatellite markers spanning chromosome 3p (n=26), 8p (n=14), 9q (n=29) and 22q (n=12) regions. We also studied the role of those allele losses in gallbladder carcinoma pathogenesis by examining 45 microdissected normal and dysplastic gallbladder epithelia accompanying gallbladder carcinoma, using 17 microsatellite markers. Overall frequencies of loss of heterozygosity at 3p (100%), 8p (100%), 9q (88%), and 22q (92%) sites were very high in gallbladder carcinoma, and we identified 13 distinct regions undergoing frequent loss of heterozygosity in tumours. Allele losses were frequently detected in normal and dysplastic gallbladder epithelia. There was a progressive increase of the overall loss of heterozygosity frequency with increasing severity of histopathological changes. Allele losses were not random and followed a sequence. This study refines several distinct chromosome 3p, 8p, 9q and 22q regions undergoing frequent allele loss in gallbladder carcinoma that will aid in the positional identification of tumour suppressor genes involved in gallbladder carcinoma pathogenesis.

Influence of family income on hospital visits for asthma among Canadian school children

BACKGROUND

A study was undertaken to investigate the mechanisms by which socioeconomic status may influence asthma morbidity in Canada.

METHODS

A total of 2968 schoolchildren aged 5-19 years with reported asthma were divided into three family income ranges. Hospital visits and risk factors for asthma, ascertained by questionnaire, were compared between the three groups.

RESULTS

The mean (SE) annual period prevalence of a hospital visit was 25.0 (3.1)% among schoolchildren with household incomes of less than $20 000 Canadian compared with 16.0 (1.3)% among those with incomes of more than $60 000 (p<0.05). Students with asthma from lower income households were more likely to be younger and exposed to environmental tobacco smoke and cats, and their parents were more likely to have a lower educational attainment and be unmarried (p<0.05). Across all income groups, younger age, lower parental education, having unmarried parents, and regular exposure to environmental tobacco smoke were each associated with an increase in risk of a hospital visit (p<0.05). No increased risk was detected due to sex, having pets, and not taking dust control measures. Although not statistically significant at p<0.05, there may have been an interactive effect between income and susceptibility to environmental tobacco smoke. In the lower income group those children who were regularly exposed to second hand smoke had a 79% higher risk of a hospital visit compared with a 45% higher risk in the higher income group. In a logistic regression model the association between income and hospital visit was no longer significant after adjusting for differences in reported exposure to passive smoking.

CONCLUSION

Socially disadvantaged Canadian schoolchildren have increased asthma morbidity. Exposure to cigarette smoke appears to be one important explanation for this observation.

MMS1 protects against replication-dependent DNA damage in Saccharomyces cerevisiae

A series of yeast mutants were isolated that are sensitive to killing by the monofunctional DNA-alkylating agent methyl methanesulfonate (MMS) but not by UV or X-radiation. We have cloned and characterized one of the corresponding genes, MMS1, and show that the mms1 Delta mutant is dramatically sensitive to killing by MMS and mildly sensitive to UV radiation. mms1 Delta mutants display an elevated level of spontaneous DNA damage and genomic instability. Furthermore, the mms1 Delta cells are sensitive to killing by conditions that induce replication-dependent double-strand breaks, such as treatment with camptothecin, and incubation of a cdc2-2 strain at the restrictive temperature. rad52 Delta is epistatic to mms1 Delta for MMS and camptothecin sensitivity, indicating that Mms1 acts in concert with Rad52. However, unlike mutants of the RAD52 group, mms1 Delta cells are not sensitive to gamma-rays, which induce double-strand breaks independently of DNA replication. Together these results suggest a role for an Mms1-dependent, Rad52-mediated, pathway in protecting cells against replication-dependent DNA damage.

Efficient uptake of Yersinia pseudotuberculosis via integrin receptors involves a Rac1-Arp 2/3 pathway that bypasses N-WASP function

Efficient uptake of Yersinia pseudotuberculosis into cultured mammalian cells is the result of high-affinity binding of invasin to beta1 chain integrins. We demonstrate here that uptake requires Rac1 and Arp 2/3 function. Bacterial uptake was stimulated by GTPgammaS, but was inhibited in mammalian cells transfected with the interfering Rac1-N17 derivative. Rac1 was found to be activated in response to integrin engagement by invasin, whereas Rac1 and Arp 2/3 were found to be intensely localized around phagosomes bearing bacteria, indicating a specific role for Rac1 signalling from the nascent phagosome to downstream effectors. To determine whether the Arp 2/3 complex was a component of this proposed pathway, cells overproducing various derivatives of Scar1/WAVE1, an Arp 2/3-binding protein, were analysed. Sequestration of Arp 2/3 away from the phagocytic cup as a result of Scar1/WAVE1 overproduction dramatically inhibited uptake. To determine whether signalling from Rac1 to Arp 2/3 occurred via N-WASP, uptake was analysed in a cell line lacking expression of WASP and N-WASP. Uptake was unaffected by the absence of these proteins, indicating that beta1 integrin signalling from Rac1 to Arp 2/3 can occur in the absence of N-WASP function.

[Positive immunoglobulin A expression in human epithelial carcinoma cell lines]

OBJECTIVE

In the present study, we try to further elucidate which class of immunoglobulin is expressed in epithelial carcinoma cell lines.

METHODS

Three assays, immunohistochemistry, Western blot and enzyme-linked immunosorbent assay (ELISA) were used to detect the cellular protein extracts and the cultivated supernatant.

RESULTS

Seven human epithelial carcinoma cell lines, MCF-7 (human breast carcinoma cell line), SW480 (human colon carcinoma cell line), MGC (human gastric carcinoma cell line), HeLa (human cervical carcinoma cell line), HNE2, CNE1-LMP1 and Tet-on-LMP1-HNE2 (three human nasopharyngeal carcinoma cells) expressed IgA protein in their cellular extracts and cultivated supernatants.

CONCLUSION

Immunoglobulin is expressed in epithelium-derived carcinoma cell lines, which is in conflict with the traditional immunoglobulin theory. Our findings imply that the immunoglobulin expressed in epithelial carcinoma cells might play a role in the carcinogenesis of epithelium-derived carcinoma. Understanding the mechanism of immunoglobulin expression by cancer cells may possibly further facilitate the improvement techniques in cancer diagnosis, therapy or the mechanism of carcinogenesis.

Methylated CpG dinucleotides are the preferential targets for G-to-T transversion mutations induced by benzo[a]pyrene diol epoxide in mammalian cells: similarities with the p53 mutation spectrum in smoking-associated lung cancers

A large fraction of the p53 mutations in lung cancers from smokers are G-to-T transversions, a type of mutation that is infrequent in lung cancers from nonsmokers and in most other tumors. Previous studies have indicated that there is an association between G-to-T transversion hotspots in lung cancers and sites of preferential formation of polycyclic aromatic hydrocarbon adducts along the p53 gene. p53 codons containing methylated CpG sequences are preferential targets for formation of adducts by (+/-) anti-7beta,8alpha-dihydroxy-9alpha,10alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE). To assess the role of CpG methylation in induction of mutations by BPDE, we analyzed BPDE mutagenesis in three CpG methylated target genes: a supF shuttle vector and the cII and lacI transgenes in embryonic mouse fibroblasts. After methylation of the shuttle vector at all CpG sequences, 42% of all G-to-T transversions were at CpG sites compared with 23% in unmethylated DNA. In the cII transgene, which is methylated at CpG sequences in vivo, 83 of 147 (56%) of the BPDE-induced mutations were G-to-T transversions, and 58% (48 of 83) of all G-to-T transversions occurred at methylated CpG sequences. In the lacI gene, 68% (75 of 111) of the BPDE-induced mutations were G-to-T events, and 58 of 75 (77%) of these occurred at methylated CpG sequences. The occurrence of transversion hotspots at methylated CpGs correlated with high levels of BPDE adducts formed at such sites. This situation mirrors the one in the p53 gene in lung cancers from smokers where 236 of 465 (51%) of the G-to-T transversions occurred at methylated CpG sites. These findings further strengthen a link between polycyclic aromatic hydrocarbons present in cigarette smoke and lung cancer mutations and provide evidence that mutational processes other than C-to-T transition mutations can occur selectively at methylated CpG sequences.

Clinical outcome and client satisfaction of an anger management group program

This retrospective quasi-experimental study evaluated the effectiveness of an anger management group program for clients with mental health problems. The program, based on the cognitive-behavioral approach, was offered by outpatient mental health occupational therapy services of a community general hospital. Sixty-four clients, about 59% diagnosed with depressive disorder, enrolled in the program and participated in the study. The pre-treatment and post-treatment scores of the participants on the Anger Control Inventory and the State-Trait Anger Expression Inventory were compared. The results indicated significant reduction in the overall experience of intense anger, improvement in cognitive and behavioural coping mechanisms, and significant improvement in anger control after treatment. Most respondents (90%) found the program definitely helpful. The pace of the program and the variety of learning activities were identified as areas for improvement. The results showed the program had positive impact on anger management. Useful suggestions were identified for continuous quality improvements of the program.

Sequence-dependent interactions of two forms of UvrC with DNA helix-stabilizing CC-1065-N3-adenine adducts

The uvrA, uvrB, and uvrC genes of Escherichia coli control the initial steps of nucleotide excision repair. The uvrC gene product is involved in at least one of the dual incisions produced by the UvrABC complex. Using single-stranded (ss) DNA affinity chromatography, we have separated two forms of UvrC from both wild-type E. coli cells and overproducing cells. UvrCI elutes at 0.4 M KCl, and UvrCII elutes at 0.6 M KCl. In general, both forms, in the presence of UvrA and UvrB, actively incise UV-irradiated and CC-1065-modified DNA in the same fashion; i.e., they incise six to eight nucleotides 5' to and three to five nucleotides 3' to a photoproduct or a CC-1065-N3-adenine adduct. They produce different incisions, however, at a CC-1065-N3-adenine adduct in the sequence 5'-GATTACG- present in the MspI-BstNI 117 bp fragment of M13mp1. UvrABCI incises at both the 5' and 3' sides of the adduct (UvrABCI cut), while UvrABCII incises only at the 5' side (UvrABCII cut). Mixing UvrCI and UvrCII results in both UvrABCI and UvrABCII cuts, and the levels of these two types of cutting are proportional to the amount of UvrCI and UvrCII. DNase I footprints of the MspI-BstNI 117 bp DNA fragment containing a site-directed CC-1065-adenine adduct at the 5'-GATTACG- site show that UvrCII, but not UvrCI, binds to the adduct site. Furthermore, the pattern of DNase I footprints induced by UvrCII binding differs from the pattern of the footprints induced by UvrA, UvrAB, and UvrABCI binding. Interestingly, while the presence of unirradiated DNA enhances the efficiency of UvrABCII in incising UV-irradiated DNA, it does not enhance UvrABCII incision of the CC-1065-N3-adenine adduct formed at 5'-GATTACG-. These results show that two different forms of UvrC differ in DNA binding properties as well as incision modes at some kinds of DNA damage.

[Antibacterial activities of seven commonly used antibiotics to 106 isolated strains of porphyromonas gingivalis in vitro]

OBJECTIVE

Porphyromonas gingivalis (Pg) is one of the main putative pathogens of periodontal disease, especially of adult periodontitis. This in vitro study was aimed at observing the inhibitory activities of 7 commonly used antimicrobical drugs on 106 stains of Pg which isolated from subgingival plaques of sites with adult periodontits.

METHODS

Kirby-Bauer paper disk method was used in this study.

RESULTS

Pg was highly susceptible to Clindamycin, Sulfamzthoxazole timethoprin, Tetracycline and Cefazolin, the susceptibility rates were 93.4%, 78.3%, 60.4% and 56.6% respectively.

CONCLUSION

Majority of the strains of Pg was moderately susceptible to cefalexin and acetylspiramycin, while no strains of Pg was susceptible to Penicillin G. The concentrations of Pg solutions (10(5) CFU/ml, 10(6) CFU/ml and 10(8) CFU/ml) had not influence on the results. This data is helpful for clinically antibiotic selection of periodontal treatment.

Highly toxic and broad-spectrum insecticidal Bacillus thuringiensis engineered by using the transposon Tn917 and protoplast fusion

The chromosome of the Bacillus thuringiensis strain S184 that was toxic against the third instar larvae of Spodoptera litura with the LC(50) of 9.74 microg/ml was successfully integrated into two genes of cyt1Aa and cry11Aa using the transposon Tn917, yielding the primary engineered strain TnX. The strain TnX was highly toxic to the third instar larvae of Culex pipiens fatigans with the LC(50) of 5.12 ng/ml which was 1.82-fold higher than that of B. thuringiensis subsp. israelensis, but lowly toxic to lepidopterous larvae. By the protoplast fusion of the strain TnX and the strain S184-Tet(r) (resistance to tetracycline), the target engineered strain TnY was obtained. Against the third instar larvae of S. litura, the strain TnY LC(50) was of 4.68 micro g/ml and increased by 2.08-fold in comparison with the parent strain S184. Against the third instar larvae of C. pipiens fatigans, the strain TnY LC(50) was of 103.20 ng/ml. The two target genes of cyt1Aa and cry11Aa integrated into the chromosome were extremely stable and had little possibility of a second transposition. It was unclear whether some factors existing in the parent strain, S184, contributed to the high toxicity of the strains TnX and TnY.

The -590C/T and -34C/T interleukin-4 promoter polymorphisms are not associated with atopic eczema in childhood

Susceptibility to the development of asthma and other atopic diseases is known to have a genetic component. To date, several studies have linked chromosome 5q31 to asthma and atopy in human beings. This region harbors a cluster of cytokine and growth factor genes, IL-4 presenting as a prime atopy candidate gene, inasmuch as it plays a pivotal role in the atopy pathway. Our approach was to identify polymorphisms within the promoter regions of IL-4 and test their association with atopic eczema. Polymorphisms were typed in a cohort of 76 small nuclear families and 25 triads with childhood atopic eczema. The genotypes were used to test for linkage in the presence of association with atopic eczema. A new polymorphism, -34C/T, was identified and studied with a known polymorphism, -590C/T. On its own, each polymorphism showed no association with atopic eczema. The 2 polymorphisms were used to generate haplotypes, and a significant result was found for the -590C/-34C haplotype. However, after Bonferroni correction for multiple testing, the association became nonsignificant. Neither polymorphism predisposes to early-onset atopic eczema by itself, but suggestive linkage was found for the -590C/-34C haplotype in this study.

Memory performance in healthy elderly without Alzheimer's disease: effects of time and apolipoprotein-E

Transgenic mice expressing human APOE-epsilon4 develop an age-dependent decline in memory without pathological features of Alzheimer's disease (AD). This implicates APOE in the maintenance of memory during normal senescence, but parallel human studies are limited because longitudinal investigations of memory usually do not exclude patients with AD or "questionable" AD (QD). The current study examined the effect of APOE on cognitive function over time in elderly without dementia. We hypothesized that, compared to other APOE alleles memory decline even in healthy elderly would be greater among those with an APOE-epsilon4. The results of neuropsychological tests, grouped into domains of memory, language and visuospatial/cognitive function by factor analysis, were examined at three intervals over a seven-year period in 563 healthy elderly without AD or QD using generalized estimating equations. Memory performance declined over time, while scores on the visuospatial/cognitive and language factors did not change. Increased age was associated with lower scores, and higher education with higher scores on all factors at each interval. No APOE allele was associated with performance on a specific cognitive factor at any interval, but the presence of an APOE-epsilon4 allele was associated with a more rapid decline in the memory factor over the follow-up period. The effect was most pronounced among individuals with less than 10 years of formal education. There was no similar time-dependent relationship between APOE-epsilon4 and the language or visuospatial/cognitive factors. Transgenic mice and elderly humans without AD or QD expressing APOE-epsilon4 show a decline in memory performance over time. These observations provide evidence for an APOE-specific effect on memory during senescence.

LMP1 activates NF-kappa B via degradation of I kappa B alpha in nasopharyngeal carcinoma cells

OBJECTIVE

To elucidate the mechanisms by which Epstein-Barr virus-encoded latent membrane protein 1 activates NF-kappa B in nasopharyngeal carcinoma cells.

METHODS

A tetracycline-regulated LMP1-expressing nasopharyngeal carcinoma cell line, Tet-on-LMP1-HNE2, was used as the cell model. The kinetics of the expression of proteins, including LMP1, I kappa B alpha and I kappa B beta, was analyzed by Western blotting. The subcellular localization of NF-kappa B (p65) was detected by indirect immunofluorescence assay. The NF-kappa B transactivity was studied by transient transfection and reporter gene assay.

RESULTS

I kappa B alpha was phosphorylated and degraded after the inducible expression of LMP1, although the total protein levels remained stable. The steady-state level of total I kappa B beta protein may have resulted from the initiation of an autoregulation loop after the activation of NF-kappa B. No change in the I kappa B beta level was detected. NF-kappa B (p65) was translocated from the cytoplasm to the nucleus following degradation of I kappa B alpha. After the introduction of the dominant-negative mutant of I kappa B alpha (Del 71) into Tet-on-LMP1-HNE2 cells, both nuclear translocation and transactivation of NF-kappa B induced by LMP1 was significantly inhibited.

CONCLUSIONS

The results indicated that in nasopharyngeal carcinoma cells, LMP1 activated NF-kappa B via phosphorylation and degradation of I kappa B alpha, but not I kappa B beta. The dominant-negative mutant of I kappa B alpha (Del 71) could completely inhibit both the nuclear translocation and transactivation of NF-kappa B induced by LMP1.

[Observation of the biological characterizations of nasopharyngeal epithelial cells by EB virus infection in early phase of immortalization]

The multi-stage cell model of the nasopharyngeal carcinoma development in vitro by Epstein-Barr virus transformation is beneficial for the elucidation of the mechanism of nasopharyngeal cancer. To observe the biological changes of primary human nasopharyngeal epithelial cells in early phase of immortalization, in this study, we have detected the morphological changes and the expression profile of senescence-associated beta-galactosidase (SA-beta-Gal) in primary culture. In addition, the expression of EB virus latent membrane protein 1 (LMP1) and the growth curve of primary cells were also detected. Our results showed a low percentage of cells infected with EB virus expressing SA-beta-Gal activity at the late primary culture. In morphology, the cells also formed multilayer foci, and the cell population doubling time was showed. These results demonstrated that the nasopharyngeal epithelial cells by EB virus infection have passed through the senescence and entered the early phase of immortalization. These cells have some of the transformed characteristics. Our results provided the data for further study on the mechanism of immortalization and the establishment of human nasopharyngeal epithelial cell line.

CD43 potentiates CD3-induced proliferation of murine intestinal intraepithelial lymphocytes

The involvement of CD43 in cell proliferation of murine intestinal intraepithelial lymphocytes (IEL) has been studied in in vitro CD3-stimulated cell cultures. In the presence of either IL-2 or IL-15, CD3 stimulation of IEL resulted in low levels of proliferation as measured by thymidine incorporation, whereas no proliferation occurred upon CD3 stimulation in the absence of cytokines. The combination of both cytokines to IEL cultures synergistically enhanced CD3-induced proliferation by approximately threefold that of cultures supplemented with either cytokine alone. Most importantly, however, proliferation of IEL was significantly greater when CD3 stimulation occurred in conjunction with CD43 triggering, indicating that CD43 functions as a coactivational signal for murine IEL. These findings indicate that a spectrum of potential proliferative responses exist among murine IEL depending on the types and combinations of signals received, and that because under normal conditions murine IEL are largely devoid of CD28 expression, a classical T-cell coactivational molecule, the capacity for high-level IEL proliferation may reside with CD43.

The Follicular versus Marginal Zone B Lymphocyte Cell Fate Decision Is Regulated by Aiolos, Btk, and CD21

Most splenic B cells in mice that lack Aiolos are mature IgD(hi)IgM(lo) follicular lymphocytes, suggesting that maturation signals delivered via the BCR are enhanced in the absence of Aiolos. The enhanced maturation of follicular B cells is accompanied by the absence of MZ B lymphocytes and the downregulation of CD21 expression in follicular B cells, all of which depend on the generation of signals via Btk, which is in epistasis to Aiolos. The inverse relationship between the strength of BCR signaling and MZ B cell development is supported by an examination of MZ B cells in CD21 null mice. These data support the view that antigens (in contrast to "tonic" signals) drive the development of naive B cells.

Genome-wide allelotyping analysis reveals multiple sites of allelic loss in gallbladder carcinoma

Although gallbladder carcinoma (GBC) is a highly malignant neoplasm, there is very limited information about the molecular changes involved in its pathogenesis. To identify the chromosomal locations of putative tumor suppressor gene loci involved in the pathogenesis of GBC, we conducted a genome-wide allelotyping or loss of heterozygosity (LOH) analysis of GBCS: Microdissected tissue from 24 archival GBCs and their matched control DNAs were analyzed for PCR-based LOH using 169 microsatellite markers spanning all nonacrocentric autosomal arms and the X chromosome. The chromosomal arms with the greatest frequencies of LOH (> or = 60%) were 3p, 6q, 7q, 8p, 9p, 9q, 11q, 12q, 17p, 18q, 19p, 22q, and XQ: The average fractional allele loss index in GBC cases was high (0.43) and frequent breakpoints were detected in gallbladder tumors. Of interest, 21 different regions of frequent LOH (hot spots) defined as > or = 50% for individual GBC samples were detected in this neoplasm, nearly half of them confined to one microsatellite marker. We conclude that in GBC at least 21 chromosomal regions with frequent allele losses are involved, suggesting that several putative tumor suppressor genes are inactivated in its pathogenesis. Overall, these data provide global estimates of the extent of genetic changes leading to GBC and will be useful for the identification of new tumor suppressor genes and for multiple new markers for translational research.

Aminopeptidase from Sphingomonas capsulata

A novel aminopeptidase with unique substrate specificity was purified from a culture broth of Sphingomonas capsulata. This is the first reported aminopeptidase to demonstrate broad substrate specificity and yet release glycine and alanine with the highest efficacy. On a series of pentapeptide amides with different N-terminal amino acids, this enzyme efficiently releases glycine, alanine, leucine, proline, and glutamate with the lowest turnover value of 370 min(-1) for glutamate. At pH 7.5 (pH optimum) and 25 degrees C, the kinetic parameters for alanine para-nitroanilide were found to be k(cat) = 7600 min(-1) and K(m) = 14 mm. For alanine beta-naphthylamide, they were k(cat) = 860 min(-1) and K(m) = 6.7 mm. Polymerase chain reaction primers were designed based upon obtained internal sequences of the wild type enzyme. The subsequent product was then used to acquire the full-length gene from an S. capsulata genomic library. An open reading frame encoding a protein of 670 amino acids was obtained. The translated protein has a putative signal peptide that directs the enzyme into the supernatant. A search of the amino acid sequence revealed no significant homology to any known aminopeptidases in the available data bases.

[EBV latent membrane protein 1 induces p53 expression via NF-kappa B in nasopharyngeal carcinoma]

OBJECTIVE

To ascertain if EBV-encoded latent membrane protein 1 (LMP1) induces p53 expression via NF-kappa B signaling.

METHODS

A nasopharyngeal carcinoma cell line, Tet-on-LMP1 HNE2, transfected with LMP1, the expression of which was regulated by tetracycline, was used in this study. Functional activity of NF-kappa B was determined by luciferase reporter assay and expression of p53 and bcl-2 was detected by Western blot.

RESULTS

LMP1 induced p53 expression via NF-kappa B signaling pathway. Induction of p53 expression could be blocked by phosphorothiate analogs of antisense oligonucleotides to NF-kappa B p65 and LMP1, but not by NF-kappa B p50. However, it seemed that LMP1 had no influence on bcl-2 expression in nasopharyngeal carcinoma.

CONCLUSION

Induction expression of p53 by EBV-encoded LMP1 implies that p53 may act as a mediator in apoptosis triggered by LMP1, which brings about a complex balance in nasopharyngeal carcinogenesis.

Elicitor induced defence responses in medicago sativa

•  The effects are reported here of an elicitor prepared from liquid cultures of an isolate of Verticillium albo-atrum, which is nonpathogenic to Medicago sativa, on accumulation of H₂ O₂ , medicarpin, deposition of phenolic polymer and phenylalanine ammonia-lyase (PAL) activity in cultured cells of Medicago sativa L. cv. Kabul (lucerne). •  PAL activity and phytoalexins were assayed spectrophotometically and by HPLC, respectively. The scopoletin fluorescence-quenching and thioglycolic acid methods were used to measure H₂ O₂ and phenolic polymer deposition, respectively. •  Studies with inhibitors suggested that an NAD(P)H oxidase and a peroxidase were involved in the elicitor stimulated accumulation of H₂ O₂ and that an increase in cytosolic Ca²⁺ , but not H₂ O₂ , was part of a signalling pathway leading to the induction of defence responses. •  Both the influx of Ca²⁺ and release of Ca²⁺ from intracellular stores forms part of the signalling pathway leading from perception of elicitor to induction of defence responses. Although H₂ O₂ is not part of the pathway, evidence is presented that O₂ ^- is part of the signal transduction chain.

[AFLP markers of restoring genes of the wild-abortive hybrid rice]

Fertile and sterile pools were set up by bulked segregant analysis (BSA) based on the selection for the highly fertile and highly sterile plants of Shanyou 63 F2 population. The AFLP analysis of the two pools indicated that 64 primer combinations amplified 3,477 stable and clear bands. Exception of the combination E-AGC/M-CAA, all primer combinations had not detected polymorphism between the two pools. It was proved by investigation of two parents, individuals of F2 segregant population, backbone sterile lines and restorer lines that the polymorphic fragment AP1 generated from the primer E-AGC/M-CAA was associated with the restoring gene. AP1 was a single copy detected by Southern blot hybridization. The distance between AP1 and the restoring gene was 4.76 cM.

Identification and expression of the motilin precursor in the guinea pig

Motilin has never been isolated from rodents, the most frequently used laboratory animals, despite several attempts. We have isolated and sequenced the motilin precursor from duodenal mucosa of guinea pig (GenBank accession number AF323752) and studied its expression in several tissues. The percent homology with human motilin is the lowest yet observed due to several unique substitutions in the C-terminal end. As expected, the precursor was present in the gut mucosa with the exception of the gastric corpus. It was also present in medulla oblongata, nucleus of the solitary tract, hypophysis, spinal cord, hypothalamus, and cerebellum but not in the cerebral cortex. For the first time we demonstrated motilin expression in the thyroid.

Preliminary results from an EIT breast imaging simulation system

An electrical impedance tomography (EIT) simulation system for breast imaging has been developed using impedance data from a previous study and a finite-element model (FEM). This system has the functionality to construct various models of the breast, image the boundary voltages developed from any injection schema and provide parametric Cole-Cole modelling. Simulations indicate that breast carcinoma can be imaged and multi-frequency Cole-Cole dispersion data can be extracted. This is intended as the first stage towards providing an artificial intelligence based system capable of producing clinically relevant analytical data.