[Epidemiological and pathogenic features of a bacillary dysentery outbreak in a boarding school caused by Shigella sonneri].

Objective: To investigate the etiologic and epidemiologic features of an infectious diarrhea outbreak in a boarding school in Fuyang city, Anhui province. Methods: Traceability hypothesis of this study was tested according to the epidemiological characteristics of the cases. Feces, anal swabs, water samples and food residues related to the patients and chefs were collected for pathogen isolation and detection. Biochemical identification, virulence gene detection, drug susceptibility test, PFGE and multilocus sequence typing were performed. Results: The incidence rate (3.41%) of different dormitory buildings within the water supply area by shallow wells was higher than that (0.98%) of the deep wells, with statistical significance (χ(2)=17.215, P<0.001). Sixteen strains belonged to the Shigella Sonneri family were isolated from the patient's samples, and all carrying the ipaH gene. Seven strains belonged to sen and ial genes. Set1 gene that did not appear in all the 16 strains were highly resistant to ampicillin, tetracycline, compound xinnomine, cefazoline, cefotaxime, gentamicin, naphthidinic acid and streptomycin, including 9 strains to doxycycline. The pulse field pattern of the 16 strains of Shigella sonneri appeared the same, with the ST type as ST152. Conclusion: When combined data from the etiological and epidemiological investigation, it was confirmed that Shigella sonneri was the pathogen of this outbreak, and water from the shallow wells might be responsible for the source of infection.

Bicluster and pathway enrichment analysis related to tumor progression of hepatocellular carcinoma.

OBJECTIVE: Hepatocellular carcinoma is one of the most aggressive cancers with poor prognosis worldwide. Tumor progression remains a significant cause of high mortality in patients with hepatocellular carcinoma. However, the molecular mechanism underlying tumor progression of hepatocellular carcinoma has not been completely unraveled currently. The aim of this study was to gain insight into the molecular mechanisms of tumor progression of hepatocellular carcinoma. MATERIALS AND METHODS: We performed microarray analysis on 24 tissue specimens obtained at the time of surgical resection or liver transplantation from 24 patients with hepatocellular carcinoma downloaded from the Gene Expression Omnibus database. RESULTS: Our analysis indicated that several differentially expressed genes might play crucial roles in the progression of hepatocellular carcinoma, such as GADD45G, SPTBN1, CDC27, TPD52 and INSIG1. GADD45G and SPTBN1 not only contribute to tumor progression in hepatocellular carcinoma, but also correlate with poor prognosis in esophageal squamous cell carcinoma and pancreatic cancer respectively. Futhermore, we performed pathway enrichment analysis and found enriched pathways, including "Proteasome", "Alanine, aspartate and glutamate metabolism", "TGF-beta signaling pathway", "Wnt signaling pathway", and so on. CONCLUSIONS: Our findings confirmed the presence of multiple molecular alterations during tumor progression and indicated the differentially expressed genes might be involved in tumor progression though multiple pathways. Genes GADD45G and SPTBN1 might correlate with poor prognosis in hepatocellular carcinoma as has already been shown for other malignancies of the gastrointestinal tract.

Epigenetic regulation and cancer (review).

'Epigenetics' is defined as the inheritable changes in gene expression with no alterations in DNA sequences. Epigenetics is a rapidly expanding field, and the study of epigenetic regulation in cancer is emerging. Disruption of the epigenome is a fundamental mechanism in cancer, and several epigenetic drugs have been proven to prolong survival and to be less toxic than conventional chemotherapy. Promising results from combination clinical trials with DNA methylation inhibitors and histone deacetylase inhibitors have recently been reported, and data are emerging that describe molecular determinants of clinical responses. Despite significant advances, challenges remain, including a lack of predictive markers, unclear mechanisms of response and resistance, and rare responses in solid tumors. Preclinical studies are ongoing with novel classes of agents that target various components of the epigenetic machinery. In the present review, examples of studies that demonstrate the role of epigenetic regulation in human cancers with the focus on histone modifications and DNA methylation, and the recent clinical and translational data in the epigenetics field that have potential in cancer therapy are discussed.

Clinical study of transarterial chemoembolization combined with 3-dimensional conformal radiotherapy for hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Monotherapy is not very effective for intermediate or advanced stage HCC. Efficacy of combined therapy using transarterial chemoembolization (TACE) with three-dimensional conformal radiotherapy (3-DCRT) for advanced HCC should be evaluated. METHODS: HCC patients were selected from our patient database. The sequence of treatments that patients underwent was several courses of TACE followed in 2-4 weeks by 3-DCRT. The median tumor irradiation dose was 44Gy. Toxicity, tumor response, and overall survival rate were analyzed. RESULTS: 140 HCC patients were followed up by the last follow-up time. Among these patients, hepatic toxicities due to treatment were notable in 15 cases. Gastrointestinal bleeding after the overall treatment occurred in 3 cases. Leukopenia of grade III was detected in 1 case. Radiation-induced liver disease (RILD) was observed in 3 patients. Among 140 patients, 27, 97, and 16 cases achieved partial response, stable disease, and progressive disease, respectively. The overall survival rates of 1-year, 3-years, and 5-years were 66%, 29%, and 13%, respectively, with a median survival time of 18 months. Both Child-Pugh grade and radiation dose were determined to be independent predictors for overall survival from multivariate analysis. CONCLUSION: The combined modality of TACE and 3-DCRT is a promising treatment for unresectable HCC. A large-scale, prospective randomized trial should be performed to confirm the utility of this combined therapy.

K-ras mutational status predicts poor prognosis in unresectable pancreatic cancer.

OBJECTIVE: To determine the prognostic value of K-ras mutations in plasma DNA of unresectable pancreatic cancer patients. METHODS: Blood samples were collected from 91 patients with unresectable pancreatic cancer prior to treatment. K-ras gene was amplified from the circulating plasma DNA. Mutations were detected by direct sequencing. The relationship between the types of K-ras gene and prognosis of unresectable pancreatic cancer was evaluated. RESULTS: K-Ras codon 12 mutations were found in 30 of 91(33%) plasma DNA samples, 17mutations were c.35G>A (p.G12D), 11 were c.35G>T (p.G12V) and only 2 were c.34G>C (p.G12R)). K-ras codon 12 mutations could significantly reflect the clinical parameters, including TNM tumor staging (P=0.033) and liver metastasis (P=0.014). The median survival time of patients with K-ras mutations was shorter than that of patients with wild-type K-ras gene (3.9 months vs. 10.2 months, P<0.001). K-ras codon 12 mutation from plasma DNA was an independent negative prognostic factor for survival (hazard ratio, 7.39; 95% confidence interval, 3.69-14.89). CONCLUSION: K-ras mutation in plasma DNA is a predictive biomarker for a poor prognosis of unresectable pancreatic cancer patients.

Cloning and RNAi-mediated functional characterization of MaLac2 of the pine sawyer, Monochamus alternatus.

Laccase, a member of a group of proteins collectively known as multicopper oxidases, is hypothesized to play an important role in insect cuticle sclerotization by oxidizing catechols in the cuticle to their corresponding quinones, which then catalyze protein cross-linking reactions. Laccase 2 has been proved as the gene required for beetle cuticle tanning through RNA interference (RNAi) experiments on red flour beetle Tribolium castaneum. The pine sawyer beetle, Monochamus alternatus (Coleoptero: Cerambycidae) is the insect serving as a major vector of the pinewood nematode, Bursaphelenchus xylophilus, which is the causative agent for pine wilt disease. The cDNA of MaLac2 was cloned from the insect in this study. The conceptual amino-acid sequence deduced was much conserved with other known insect laccases, particularly with the enzyme of Tribolium castaneum. Injection in hemolymph of pine sawyer larva of dsRNA targeting the laccase 2 mRNA leads to important alterations of the tanning, hardening and sclerotization of the pupal and adult cuticles. Defaults appear in a dose-dependent manner and high loads of dsRNA are lethal. The decrease of the endogenous laccase 2 mRNA affects the procuticle which is thinner and without the characteristic piling up of successive layers. The observations reinforce the role of laccase 2 as an essential phenoloxidase for making cuticle.

Diagnostic value and complications of fine needle aspiration for primary liver cancer and its influence on the treatment outcome-a study based on 3011 patients in China.

AIM: To determine the diagnostic value and major complications of fine-needle aspiration (FNA) for primary liver cancer (PLC) and its influence on the treatment outcome and prognosis. METHODS: Information was gathered retrospectively for 3011 patients who presented with suspected PLC. Of which 2528 cases underwent ultrasound-guided fine-needle aspiration (US-FNA) biopsy. Patients were followed up through repeated office visits and imaging studies with a median follow-up of 7 months (range, 1-29 months). RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy of cytological diagnosis by FNA biopsy for detection of liver malignancy were 91.5%, 100.0%, 100.00%, 59.1% and 92.4% respectively. All patients with AFP> or = 400 microg/L were associated with malignancy. Of 1154 patients with AFP<400 microg/L who were finally proved PLC, 945 were detected by FNA alone. Major complications included bleeding in 11 cases (5 of them died later), occurred mainly in hepatocellular carcinoma with superficial location, large tumors and severe cirrhosis, and implantation metastases in 5 cases, which were recognized as a subcutaneous nodule at the previous biopsy site. Implantation metastases were treated with resection or radiotherapy. CONCLUSION: FNA biopsy is valuable for the diagnosis of PLC. However, complications of post-biopsy hemorrhage should not be ignored, as such bleeding may be fatal. Implantation seems to have little effect on the prognosis.

Expression of an immunologically reactive merozoite surface protein (MSP-1(42)) in E. coli.

The 42-kDa carboxyl-terminal processing fragment of Plasmodium falciparum merozoite surface protein-1 (PfMSP-1(42)) is one of the anti-malarial vaccine candidate antigens. In the present study, recombinant MSP-1(42) was expressed as a fusion protein in a novel E. coli host. The average yield of the recombinant protein was 48 mg/l of bacterial culture. The antigenicity and immunogenicity of the purified protein were evaluated by comparing the results with those obtained from a well-characterized recombinant MSP-1(42) (Bmp42) expressed in the baculovirus expression system previously described from our laboratory. We observed that there is a high degree of similarities between the two recombinant proteins. Based on the results from T and B cell response, in vitro parasite growth inhibition, as well as cross-reactivities with several well-characterized MSP-1 specific Mabs, the bacterial expressed protein is apparently comparable to Bmp42 in terms of immunoreactivities. Our results suggest that the bacterial expression system could be employed to express immunologically active recombinant MSP-1(42) at elevated levels. This system may be an attractive alternative for producing a protective vaccine for human use at lower cost.

In vivo expression and immunological studies of the 42-kilodalton carboxyl-terminal processing fragment of Plasmodium falciparum merozoite surface protein 1 in the baculovirus-silkworm system.

The 42-kDa carboxyl-terminal processing fragment of Plasmodium falciparum merozoite surface protein 1 (MSP-1(42)) is an anti-erythrocytic stage malaria vaccine candidate. In this study, MSP-1(42) was expressed by using the Bombyx mori nuclear polyhedrosis virus-silkworm expression system, and the antigenicity and immmunogenicity of the recombinant protein, Bmp42, were evaluated. The average yield of Bmp42, as determined by a sandwich enzyme-linked immunosorbent assay (ELISA), was 379 microg/ml of infected silkworm hemolymph, which was >100-fold higher than the level attainable in cell culture medium. N-terminal amino acid sequencing revealed that Bmp42 was correctly processed in silkworm cells. Data from immunoblotting, as well as from the inhibition ELISA, suggested that the conformational B-cell epitopes of MSP-1(42) were recreated in Bmp42. Immunization of rabbits with Bmp42 in complete Freund's adjuvant generated high-titer antibody responses against the immunogen. Specificity analyses of the anti-Bmp42 antibodies using several recombinant MSP-1(19) proteins expressing variant and conserved B-cell epitopes suggested that the anti-Bmp42 antibodies recognized primarily conserved epitopes on MSP-1(19). Furthermore, the anti-Bmp42 antibodies were highly effective in inhibiting the in vitro growth of parasites carrying homologous or heterologous MSP-1(42). Our results demonstrated that the baculovirus-silkworm expression system could be employed to express biologically and immunologically active recombinant MSP-1(42) at elevated levels; thus, it is an attractive alternative for producing a protective MSP-1(42) vaccine for human use.

Effects of arsenic on blast transformation and DNA synthesis of human blood lymphocytes.

Effects of inorganic arsenicals on DNA synthesis in unsensitized human blood lymphocytes were biphasic: the chemicals at very low concentrations enhanced blast transformation and DNA synthesis, whereas higher concentrations inhibited the transformation and DNA synthesis. The concentrations of arsenicals at which the maximum stimulating effect was found were 1 x 10(-5) M, 1 x 10(-6) M or 2 x 10(-6) M, and 0.8 x 10(-6) M or 1 x 10(-6) M for sodium arsenite exposure of 1 h, 3 days and 6 days, respectively; for sodium arsenate, 1 x 10(-5) M, 1 x 10(-5) M, and 2 x 10(-6) M or 5 x 10(-6) M, respectively. Arsenicals must be present for the entire 6 days culture period to produce maximum stimulation of blast transformation of human lymphocytes. The longer exposure of the lymphocytes to arsenicals, the lower the concentrations of arsenicals at which the maximum stimulating effect was found. The stimulating effect of trivalent arsenic (sodium arsenite) was stronger than pentavalent arsenic (sodium arsenate).

Expression of grass carp growth hormone by baculovirus in silkworm larvae.

A total of five recombinant Bombyx mori nuclear polyhedrosis viruses (BMNPV) carrying the grass carp (Ctenopharyngodon idellus) growth hormone (GH) cDNA were constructed in this study. Two of them were able to express the hormone up to a level of 12 microgram/ml medium when cultured B. mori cells were infected for 4 days. Inoculation of the viruses into silkworm (B. mori) host significantly increased the level of GH achievable. The amount of hormone produced per larva was estimated to be around 1 mg. The recombinant grass carp GH had immunological and biological activities similar to the native hormone. The N-terminal sequence of the recombinant hormone was the same as the native one, indicating that the fish signal peptide was correctly processed by the insect cells. Silkworm powder prepared from larvae infected with the recombinant virus was used as food supplement for fish. Compared with the control, this dietary supplement was effective in increasing the growth rate of juvenile carp.

[Studies on DNA damage in human blood lymphocytes using the single cell microgel electrophoresis technique].

In this paper, the single cell microgel electrophoresis (SCG) technique was described in detail, and effects of DNA damage of human blood lymphocytes induced by gamma-rays radiation, H2O2 and CdCl2 were studied using this technique. It was shown that gamma-rays, H2O2 and CdCl2 all caused the increase of DNA migration length in the lymphocytes in the dose-dependent manner. The principle of the SCG technique, cause of DNA migration in the untreated control cells, and noticeable details in the SCG technique were also discussed.

Antigenic determination fragments of alpha-momorcharin.

Alpha momorcharin is a protein isolated from the bitter gourd. It has a number of biological activities including induction of abortion, inhibition of tumor growth and anti-HIV. All these activities may be related to the ribosome-inhibiting activity of the protein. Repeated use of alphaMMC can elicit an antigenic response which may neutralize its biological activity. To overcome this problem, we need to know which part of the molecule is the antigenic determinant. In this study, we constructed a random fragment expression library from the alphaMMC cDNA and screened it with three anti-alphaMMC sera. A total of 9 positive clones were picked and sequenced. Based on the sequence information obtained, we were able to deduce three regions at which antibodies raised against native alphaMMC seem to interact. These regions are residues 1-14, residues 71-136 and residues 195-222. Mapping of these regions against a 3D model of alphaMMC indicates that they all are located on the surface of the molecule. As residues 71-136 are found to be in close proximity to the active site involved in ribosome inactivation, treatment with a monoclonal antibody directed to this area was shown to be effective in inactivating the inhibitory effect of alphaMMC on in vitro protein synthesis.

Determination of age-related changes of cytochrome P-450 sensitive to mepyramine in rat hepatic microsomes.

The cytochrome P-450 (Cyt P-450) sensitive to mepyramine (HP-450) in liver microsome is a protein that possesses properties of both H1 receptor and cytochrome P-450. We used [3H]mepyramine radioligand binding assay and enzymological technique to study the kinetic properties of HP-450 and Cyt P-450. Age-related changes in the Bmax, Kd of HP-450 and Cyt P-450 in rat hepatic microsome were demonstrated. The levels of Bmax for both HP-450 and the Cyt P-450 dramatically increased in the postnatal period from the second to the eighth week, and reached maximum steady status during the eighth to tenth week. The values of Bmax of HP-450 correlated well with the content of Cyt P-450 in rat liver microsome (r = 0.625). The affinity of HP-450 (Kd) decreased with the growth of rats during postnatal. No sexual-related difference was observed in this experiment.

Effects of four chemicals on N-acetyltransferase activities in human U937 cell line.

The effects of p-aminobenzoic acid (PABA), procainamide (PA), anisidine (AN) and isoniazid (INH) on N-acetyltransferase (NAT) activities in cultured human cells were determined. PABA increased the specific activity of PABA NAT in the U937 cells but not in the Hep G2 cells. The enzyme activity in the PABA-treated U937 cells was restored to normal within 4 d after removing PABA from medium. These results imply that the PABA NAT activity in the U937 cells can be induced by PABA and the PABA NAT in the U937 cells is different from that in the Hep G2 cells. INH increased the INH NAT specific activity in the U937 cells but decreased the PABA NAT activity. AN decreased both the AN NAT and the PABA NAT specific activities in the U937 cells. PA did not affect the specific activities of PABA NAT or glucose-6-phosphate dihydrogenase (G-6-P DH) in the U937 cells. PABA also increased the specific activities of AN NAT and G-6-P DH. This implies that the induction effect of PABA on the PABA NAT activity is not specific. In this study the PABA NAT specific activity was increased only by PABA, and the INH NAT activity only by INH. However, the AN NAT activity could be induced by PABA but not by AN. These results indicate that induction of some but not all NAT activities has a limiting specificity.

Chromosomal aberrations and sister-chromatid exchanges in lymphocytes of workers exposed to sulphur dioxide.

The frequencies of chromosomal aberrations and sister-chromatid exchanges (SCE) in peripheral blood lymphocytes of 40 workers chronically exposed to sulphur dioxide (SO2) at a sulphuric acid factory in Taiyuan City (North China), were studied. It was shown that the mean frequency of chromosomal aberrations and the mean frequency of lymphocytes with chromosomal aberrations of the SO2-exposed workers were both higher than the controls. The mean per 1000 metaphase frequencies of severe chromosomal aberration types (chromosome rings, translocations, and dicentrics) of the workers and the controls were 9.63 and 2.27, respectively. The difference between them was statistically significant (p less than 0.01). It was also shown that the mean SCEs/cell of SO2-exposed workers and non-exposed controls were 6.72 +/- 0.22/cell and 2.71 +/- 0.13/cell (p less than 0.01) respectively. SCEs/cell in 39 workers were all higher than 5, only 1 worker was 4.73. However, 41 controls were all lower than 4, only 1 control was 4.92. The difference between the worker and the control group was statistically significant. These results show that SO2 is a clastogenic and genotoxic agent. No positive correlation between the frequencies of chromosomal aberrations or SCE and length of service in the workers has been observed. No significant difference between smokers and non-smokers was found in these assays.

Observation of frequencies of lymphocytes with micronuclei in human peripheral blood cultures from workers in a sulphuric acid factory.

Frequencies of lymphocytes with micronuclei (MNF) in human peripheral blood cultures from workers in a sulphuric acid factory (the SO2 concentrations in the workplace ranged from 0.34 mg/m3 to 11.97 mg/m3 air) were investigated. It was shown that among 40 workers, the MNF of 28 workers was more than 0.1%, and the MNF of 7 workers was greater than the upper limit of the normal range (0.2%). The mean MNF of the worker and the control group was 0.168% and 0.071%, respectively. The difference between them was statistically significant (P less than 0.001). It implies that SO2 is a clastogenic and genotoxic agent. No positive correlation between the MNF and length of service in workers has been observed. In the control population, the MNF of smokers was significantly higher than that of non-smokers (P less than 0.001).