A promising voltammetric biosensor based on glutamate dehydrogenase/Fe3O4/graphene/chitosan nanobiocomposite for sensitive ammonium determination in PM2.5

A novel NH₄⁺ voltammetric electrochemical biosensor was constructed by immobilizing glutamate dehydrogenase (GLDH)/Fe₃O₄/graphene (GR)/chitosan (CS) nanobiocomposite onto a glassy carbon electrode (GCE). On the GLDH/Fe₃O₄/GR/CS/GCE, GLDH catalyzed the reversible reaction, i.e., the reductive amination of α-ketoglutaric acid and the oxidative deamination of L-glutamate. The electrons produced in the enzymatic reactions were transferred to the surface of the electrode via the [Fe(CN)₆]^3-/4- couple, which helped for the amplification of the electrochemical signal. The electrochemical detection of NH₄⁺ was based on the fact that the enhanced response current was proportional to the NH₄⁺ concentration. Owing to the combination of the advantages of the synergistic effects of Fe₃O₄ nanospheres, GR and CS, a promising platform for NH₄⁺ sensing was provided. Under optimum conditions, the introduced biosensor had a linear range of 0.4-2.0 μM for NH₄⁺ with the detection and quantification limits of 0.08 and 0.27 μM, respectively. Moreover, the biosensor exhibited good sensitivity and excellent reproducibility. It could retain 91.8% of its original response after two weeks of storage at 4 °C, suggesting satisfactory stability. Additionally, the proposed biosensor was successfully applied to detect NH₄⁺ levels in PM_2.5 samples, indicating its feasibility for application in NH₄⁺monitoring in the environmental fields.

Visible-light-induced photo-Fenton process for the facile degradation of metronidazole by Fe/Si codoped TiO2

This work investigated the feasibility and efficiency of a heterogeneous photo-Fenton catalyst, Fe/Si codoped TiO₂, for the degradation of metronidazole (MNZ) under visible light irradiation. The Fe/Si codoped TiO₂ was prepared via a facile and simple sol–gel solvothermal process followed by annealing at 480 °C for 4 hours. High resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) measurements revealed that the photo-Fenton process did not change the structure, textural and surface morphologies of this catalyst. Elemental mapping results indicated the good dispersion of Fe and Si ions in TiO₂. Nitrogen adsorption and desorption measurements indicated that Si doping increased the surface area of the catalysts. The Fe and Si doping narrowed the band gap of TiO₂. They also facilitated the transfer of photo-generated electrons from TiO₂ to Fe(iii). Under visible light irradiation and the optimum operating conditions, MNZ could be completely degraded in 50 min by this catalyst within a wide pH range. Hydroxyl radicals and holes were verified to be responsible for degrading MNZ. The leaching of iron ions was less than 0.047 ppm even after illuminating the catalyst for 6 hours, indicating the good stability of the Fe/Si codoped TiO₂. The as-prepared catalysts with excellent catalytic activity, and remarkable reusability and stability could provide a new insight into the preparation of photocatalysts and have wide applications for antibiotics removal.

This work investigated the feasibility and efficiency of a heterogeneous photo-Fenton catalyst, Fe/Si codoped TiO₂, for the degradation of metronidazole (MNZ) under visible light irradiation.

Visible-light-activated photoelectrochemical biosensor for the detection of the pesticide acetochlor in vegetables and fruit based on its inhibition of glucose oxidase

A new and sensitive photoelectrochemical (PEC) biosensor which is visible-light-activated was fabricated based on acetochlor’s ability to inhibit glucose oxidase (GOx) activity.

A meta-analysis of external fixation and flexible intramedullary nails for femoral fractures in children

BACKGROUND

The purpose of this meta-analysis was to compare the outcomes of external fixation and flexible intramedullary nails for femoral fractures in children between 5 and 15 years of age based on the current evidence.

MATERIALS AND METHODS

We searched relevent studies in the following database: Cochrane library, PubMed and EMABASE up to May 2014. All randomized controlled trials, Clinical controlled trials and retrospective controlled studies comparing external fixation and flexible intramedullary nails in femoral fractures of children were included. Data was extracted independently for meta-analysis.

RESULTS

Seven trials altogether involving 338 cases of femoral fractures of children treated by external fixation (128 cases) and flexible intramedullary nails (210 cases) were included in the meta-analysis. Results showed that flexible intramedullary nails was superior to external fixation in less time to union , lower postoperative infection rate and refracture rate . It may not increase delayed union, Limb-length discrepancy , pain and bursitis . Both fixations obtained a similar patient satisfaction.

CONCLUSION

Flexible intramedullary nail had greater advantages for the treatment of femoral fractures in children aged 5-15 years, compared to external fixation based on current meta-analysis. This conclusion will ultimately require rigorous and adequately powered randomized controlled trials to be proved.

Lipopolysaccharide derived from the digestive tract provokes oxidative stress in the liver of dairy cows fed a high-grain diet

The aims of this study were to measure oxidative stress parameters and to investigate the molecular mechanism triggered by grain-induced subacute ruminal acidosis in mid-lactation cows. Twelve Holstein-Friesian cows with an average weight of 455±28kg were divided into 2 groups and subjected to 2 diets over 18wk: either a low-grain (forage-to-concentrate ratio=6:4) or a high-grain (forage-to-concentrate ratio=4:6) diet based on dry matter. Being fed a long-term high-grain diet resulted in a significant decrease in rumen pH and a significant increase in ruminal lipopolysaccharide (LPS) at 4 h postfeeding in the morning. The increase was also observed in LPS concentrations in the portal vein, hepatic vein, and jugular vein blood plasma as well as reduced milk yield in a high-grain diet. Cows fed a high-grain diet had lower levels of catalase and glutathione peroxidase (GPx) activity and total antioxidant capacity than cows fed a low-grain diet; however, super oxide dismutase (SOD) activity and malondialdehyde (MDA) levels were higher in both the liver and the plasma of high-grain than in low-grain cows. Positive correlations were observed between plasma LPS versus hepatic MDA, plasma MDA, and hepatic SOD activity, whereas hepatic GPx and plasma GPx were negatively correlated with plasma LPS. The relative mRNA abundances of GPX1 and CAT were significantly lower in the liver of cows fed a high-grain diet than those fed a low-grain diet, whereas SOD1 was significantly higher in cows fed a high-grain diet than cows fed a low-grain diet. The expression levels of Nrf2, NQO1, MT1E, UGT1A1, MGST3, and MT1A were downregulated, whereas NF-kB was upregulated, in cows fed a high-grain diet. Furthermore, nuclear factor E2-related factor 2 (Nrf2) total protein and mRNA levels were significantly lower than in low-grains. Our results demonstrate the relationship between the translocated LPS and the suppression of cellular antioxidant defense capacity, which lead to increased oxidative stress and suggests that the Nrf2-dependent antioxidant response may be affected by higher levels of LPS translocated to the bloodstream.

Proteomic and gene expression analyses during bolting-related leaf color change in Brassica rapa

Bolting and flowering are key processes during the growth and development of Chinese cabbage (Brassica rapa L. ssp pekinensis). Understanding the molecular mechanisms underlying bolting and flowering is of significance for improving production of the vegetable. A leaf-color change from bright green to gray-green has been observed following differentiation of the flowering stem and before bolting in the vegetable, and is considered to be a signal for bolting. Proteomics in meristem tissues of an inbred line (C30) were analyzed by two-dimensional electrophoresis during the transition period. We found that some proteins were specifically expressed while others were differentially expressed. Among these, 17 proteins were specifically expressed before the color change, 18 were specifically expressed after the color change, 21 were downregulated during the color change, and 29 were upregulated. Mass spectrometric analysis (MALDI-TOF-TOF/MS) was used to analyze 17 protein spots, and four proteins (subunit E1 of vacuolar-type H+ transporter ATPase, the large subunit of Rubicon, S-adenosylmethionine synthetase, and tubulin α-2) were identified. qPCR analysis was conducted to quantify the expression of genes encoding these proteins during the transitional period. The expression of BrVHA-E1, BrSAMS, BrrbcL, and BrTUA6 was significantly different before and after the leaf-color change, suggesting that these genes might be involved in regulating flower differentiation and bolting.

Non-directed aromatic C-H amination: catalytic and mechanistic studies enabled by Pd catalyst and reagent design

This manuscript describes the systematic development of pyridine-type ligands, which promote the Pd catalyzed, non-directed amination of benzene in combination with novel, hydroxylamine-based electrophilic amination reagents. DFT calculations and mechanistic experiments provide insights into the factors influencing the arene C-H amination protocol.

Regulation of bolting and identification of the α-tubulin gene family in Brassica rapa L. ssp pekinensis

Microtubules are important components of eukaryotic cells, and they play vital roles in cell morphogenesis, carrying of signaling molecules, transport of materials, and establishing the cell polarity. During bolting of biennial plants, cell division and elongation are involved, and cell elongation inevitably involves the microtubules arrangement and expression of related genes. So we deduce that it is of great significance to figure out the mechanism of bolting and flowering in which TUA genes are involved. In the present study, bioinformatic methods were used to predict and identify the α-tubulin gene family (BrTUAs) in Brassica rapa L. ssp pekinensis (Chinese cabbage) through the alignment of AtTUA gene sequence from Arabidopsis thaliana with the B. rapa genome database (http://brassicadb.org/brad/) using the basic local alignment search tool. The change in the structure and functions of BrTUAs during the process of evolution, cis-acting elements in the promoter sequences of BrTUAs, and the expression of the identified genes was also analyzed. Twelve members of the α-tubulin gene family were identified from Chinese cabbage. The gene length, intron, exon, and promoter regions were determined to have changed significantly during the genome evolution. Only five of the 12 members were encoded completely and were observed to differ in their spatial and temporal expression. The five BrTUA promoter sequences contained different numbers of cis-elements responsive to light and low-temperature response, cis-elements responsive among which hormonal responses were significantly different. We also report that the BrTUAs were involved in the regulation of the bolting in Chinese cabbage, and propose that this process could be controlled by regulating the expression of BrTUAs.

Inflammation induced by increased frequency of intermittent hypoxia is attenuated by tempol administration

The levels of serum inflammatory cytokines and the activation of nuclear factor kappa B (NF-κB) and hypoxia inducible factor-1α (HIF-1α) in heart tissues in response to different frequencies of intermittent hypoxia (IH) and the antioxidant tempol were evaluated. Wistar rats (64 males, 200-220 g) were randomly divided into 6 experimental groups and 2 control groups. Four groups were exposed to IH 10, 20, 30, or 40 times/h. The other 2 experimental groups were challenged with IH (30 times/h) plus tempol, either beginning on day 0 (IH30T0) or on day 29 (IH30T29). After 6 weeks of challenge, serum levels of tumor necrosis factor (TNF)-α, intracellular adhesion molecule (ICAM)-1, and interleukin-10 were measured, and western blot analysis was used to detect NF-κB p65 and HIF-1α in myocardial tissues. Serum levels of TNF-α and ICAM-1 and myocardial expression of NF-κB p65 and HIF-1α were all significantly higher in IH rats than in controls (P<0.001). Increased IH frequency resulted in more significant changes. Administration of tempol in IH rats significantly reduced levels of TNF-α, ICAM-1, NF-κB and HIF-1α compared with the non-tempol-treated group (F=16.936, P<0.001). IH induced an inflammatory response in a frequency-dependent manner. Additionally, HIF-1α and NF-κB were increased following IH administration. Importantly, tempol treatment attenuated this effect.

A novel sensor for the detection of acetamiprid in vegetables based on its photocatalytic degradation compound

An electrochemical method for the indirect determination of acetamiprid was studied, using titanium dioxide photocatalysts coupled with a carbon paste electrode. The cyclic voltammetric results indicated that the photocatalytic degradation compound of acetamiprid had electroactivity in neutral solutions. The amount of acetamiprid was further indirectly determined by differential pulse anodic stripping voltammetric analysis as a sensitive detection technique. The experimental parameters were optimized with regard to the photocatalytic degradation time, pH of buffer solution, accumulation potential and accumulation time. Under optimal conditions, the proposed electrochemical method could detect acetamiprid concentrations ranging from 0.01 to 2.0μM, with a detection limit (3S/N) of 0.2nM. Moreover, the proposed method displays excellent selectivity, good reproducibility, and acceptable operational stability and can be successfully applied to acetamiprid determination in vegetable samples with satisfying results.

Fabrication of electrochemical sensor for paracetamol based on multi-walled carbon nanotubes and chitosan-copper complex by self-assembly technique

An electrochemical sensor for paracetamol based on multi-walled carbon nanotubes and chitosan-copper complex (MWCNTs/CTS-Cu) was fabricated by self-assembly technique. The MWCNTs/CTS-Cu modified GCE showed an excellent electrocatalytic activity for the oxidation of paracetamol, and accelerated electron transfer between the electrode and paracetamol. Under optimal experimental conditions, the differential pulse peak current was linear with the concentration of paracetamol in the range of 0.1-200 μmol L(-1) with a detection limit of 0.024 μmol L(-1). The sensitivity was found to be 0.603 A/mol L(-1). The proposed sensor also showed a high selectivity for paracetamol in the presence of ascorbic acid and dopamine. Moreover, the proposed electrode revealed good reproducibility and stability. The proposed method was successfully applied for the determination of paracetamol in tablet and human serum samples.

Non-alcoholic fatty liver disease is associated with progression of arterial stiffness

BACKGROUND AND AIMS

NAFLD is an independent risk factor for increased cardiovascular disease. Arterial stiffness is an index of subclinical atherosclerosis. The aims of this study were to examine prospectively the relationship between Non-alcoholic fatty liver disease (NAFLD) and the progression of arterial stiffness.

METHODS AND RESULTS

A prospective study of 728 men and 497 women free of hypertension, and diabetes at the baseline were conducted. The subjects were followed for 5 years. The progression rate of arterial stiffness was measured by calculating the increase in brachial-ankle pulse wave velocity (baPWV) the changes of the baPWV (adjusted for age) during the study period was significantly greater in the patients with NAFLD (172.4 ± 42.1 cm/s for men, 95.8 ± 36.7 cm/s for women) than in the subjects without NAFLD (70.3 ± 56.5 cm/s for men, 55.4 ± 42.2 cm/s for women). For the subjects with metabolic syndrome, after adjusting for multiple risk factors, NAFLD was a significant predictor of baPWV progression (for male, β = 0.843; P < 0.001; for female, β = 0.575; P < 0.001, respectively). In addition, results were unmodified in subjects without metabolic syndrome.

CONCLUSIONS

NAFLD was found to be an independent predictor of faster progression of baPWV even after adjusting other cardiovascular risk factors. These prospective data support a pathogenic role for NAFLD in the development of arterial stiffness.

A microfluidic device enabling high-efficiency single cell trapping

Single cell trapping increasingly serves as a key manipulation technique in single cell analysis for many cutting-edge cell studies. Due to their inherent advantages, microfluidic devices have been widely used to enable single cell immobilization. To further improve the single cell trapping efficiency, this paper reports on a passive hydrodynamic microfluidic device based on the "least flow resistance path" principle with geometry optimized in line with corresponding cell types. Different from serpentine structure, the core trapping structure of the micro-device consists of a series of concatenated T and inverse T junction pairs which function as bypassing channels and trapping constrictions. This new device enhances the single cell trapping efficiency from three aspects: (1) there is no need to deploy very long or complicated channels to adjust flow resistance, thus saving space for each trapping unit; (2) the trapping works in a "deterministic" manner, thus saving a great deal of cell samples; and (3) the compact configuration allows shorter flowing path of cells in multiple channels, thus increasing the speed and throughput of cell trapping. The mathematical model of the design was proposed and optimization of associated key geometric parameters was conducted based on computational fluid dynamics (CFD) simulation. As a proof demonstration, two types of PDMS microfluidic devices were fabricated to trap HeLa and HEK-293T cells with relatively significant differences in cell sizes. Experimental results showed 100% cell trapping and 90% single cell trapping over 4 × 100 trap sites for these two cell types, respectively. The space saving is estimated to be 2-fold and the cell trapping speed enhancement to be 3-fold compared to previously reported devices. This device can be used for trapping various types of cells and expanded to trap cells in the order of tens of thousands on 1-cm(2) scale area, as a promising tool to pattern large-scale single cells on specific substrates and facilitate on-chip cellular assay at the single cell level.

Particle therapy using carbon ions or protons as a definitive therapy for patients with primary sacral chordoma

OBJECTIVE

This study retrospectively evaluated the efficacy and toxicity of particle therapy using carbon ions or protons for primary sacral chordomas.

METHODS

We evaluated 23 patients with primary sacral chordoma treated with carbon ion therapy (CIT) or proton therapy (PT) between July 2005 and June 2011 at the Hyogo Ion Beam Medical Center, Hyogo, Japan. The median patient age was 72 years. 14 patients were treated with 70.4 Gy equivalents (GyE) in 16 fractions and 9 were treated with 70.4 GyE in 32 fractions. CIT was used for 16 patients, and PT was used for 7 patients.

RESULTS

The median follow-up period was 38 months. At 3 years, local control (LC), overall survival (OS) and progression-free survival (PFS) for all patients were 94%, 83% and 68%, respectively. The log-rank test revealed that male sex was significantly related to better PFS (p=0.029). No other factors, including dose fractionation and ion type, were significant for LC, OS or PFS. In nine patients, ≥ Grade 3 acute dermatitis was observed, and ≥ Grade 3 late toxicities were observed in nine patients. The 32-fraction protocol reduced severe toxicities in both the acute and late phases compared with the 16-fraction protocol.

CONCLUSION

Particle therapy for patients with sacral chordoma showed favourable LC and OS. Severe toxicities were successfully reduced by modifying the dose fractionation and treatment planning in the later treatment era. Thus, this therapeutic modality should be considered useful and safe.

ADVANCES IN KNOWLEDGE

This is the first study including both CIT and PT for sacral chordomas.

Chymase inhibition attenuates monocrotaline-induced sinusoidal obstruction syndrome in hamsters

Chymase stored in mast cells activates matrix metalloproteinase (MMP)-9, which may relate to the progression of sinusoidal obstruction syndrome (SOS). We investigated the preventive effect of a chymase inhibitor, TY-51469, on monocrotaline-induced SOS in hamsters. Hamsters were orally administrated with a single dose of monocrotaline (120 mg/kg) to induce SOS. Treatment with TY-51469 (1 mg/kg per day) or placebo had started 3 days before the monocrotaline administration. Two days after the monocrotaline administration, significant increases in aspartate aminotransferase, alanine aminotransferase and total bilirubin and a significant reduction of albumin were observed in plasma, but their changes were significantly attenuated by treatment with TY-51469. The numerous hepatic necrosis areas were observed in the placebo-treated group, but the ratio of necrotic area to total area in liver had been significantly reduced by treatment with TY-51469. Both chymase activity and MMP-9 level in liver were significantly augmented in the placebo-treated group. Furthermore, tumor necrosis factor (TNF)-α level in liver was also augmented in the placebo-treated group. However, the chymase activity and levels of MMP-9 and TNF-α were significantly attenuated in the TY-51469-treated group. Until 14 days after monocrotaline administration, survival rates in the placebo- and TY-51469-treated groups were 25% and 70%, respectively, and a significant difference was observed. In conclusion, chymase inhibition by TY-51469 may prevent the accelerating of severity in monocrotaline-induced SOS in hamsters.

Profile of gastrointestinal involvement in patients with systemic sclerosis

Systemic sclerosis (SSc) is a chronic autoimmune connective tissue disease. Of the numerous organ manifestations, involvement of the upper and lower gastrointestinal tract (GIT) appears to be the most frequent with regard to the clinical symptoms. However, as the frequency and clinical relevance of GI involvement in patients with SSc are not known in detail, the German network of the systemic sclerosis (DNSS) has developed a detailed questionnaire to evaluate the extent and profile of gastrointestinal involvement in SSc patients. The multi-symptom questionnaire was used at baseline and after 1 year in registered patients of the DNSS. In addition, the results were compared with gastrointestinal disorders in patients with SSc and other rheumatic diseases, as well as with the medical history of the patients. In total, 90 patients were included in the study. The results of the study show that in reality, a much higher (nearly all) percentage of (98,9%) patients than expected suffer from GI-symptoms, regardless of the stage of their disease. Of these, meteorism (87,8%) was the most common followed by coughing/sore voice (77,8%), heartburn (daytime 68,9%, nighttime 53,3%), diarrhea (67,8%), stomach ache (68,9%) and nausea (61,1%). Although SSc patients were treated according to the respective recommendations, only limited improvements with regard to GI-symptoms could be achieved after 1 year of follow-up. In addition, the study revealed that the multi-symptom questionnaire is a useful tool to contribute to identify the gastrointestinal sequelae in systemic sclerosis.

Establishment and biological characteristics of a Jingning chicken embryonic fibroblast bank

Using tissue explantation and cryopreservation biotechniques, a Jingning chicken embryonic fibroblast bank was successfully established, which includes 43 embryo samples and a stock of 178 cryovials, each one containing 3.0×10⁶ cells. Most of the cells were apparently fibroblasts in their morphology, and the population doubling time (PDT) was about 48 h. The total chromosome number of a diploid cell was 78. According to karyotyping and G-banding, the diploid rate in the cell bank was 97.62±2.12%. The cells were tested for microbial contamination and found free of infections from bacteria, fungi, viruses and mycoplasms. There was no cross-contamination from other cell lines as revealed by lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) isoenzyme polymorphisms. Six fluorescent proteins were transfected into the Jingning chicken embryonic fibroblasts, and the transfection efficiencies of these genes were between 10.1 and 41.9%. All the tests showed that the quality of the cell line conforms to the quality criteria of the ATCC (American type culture collection). This work succeeded not only in preserving the genetic resources of Jingning chicken, but it also established a new protocol to preserve endangered animal breeds.

Chymase as an important target for preventing complications of metabolic syndrome

Chymase plays a crucial role in angiotensin II formation in various tissues. Angiotensin II induces gene expressions of transforming growth factor (TGF)-β and matrix metalloproteinase (MMP)-9, and chymase also converts precursors of TGF-β and MMP-9 to their active forms. All of angiotensin II, TGF-β and MMP-9 are considered to be closely involved in the development and progression of metabolic syndrome and its complications. In a diabetic animal model, chymase induced pancreatic disorganization via attack of oxidative stress induced by augmentation of chymase-forming angiotensin II. In atherosclerotic lesions in patients, accumulation of chymase-positive cells was observed, and chymase inhibition prevented the development of atherosclerosis in an animal model. In Apo E-deficient mice, chymase inhibition prevents the development of angiotensin II-induced abdominal aneurysmal aorta (AAA). In this model, the AAA development on an increase in MMP-9 activities induced by angiotensin II, but the inhibition of MMP-9 activation by chymase inhibitor resulted in attenuation of the AAA development. Cardiac dysfunction after myocardial infarction was also attenuated by chymase inhibition. Steatosis and fiblosis in liver were strongly prevented by chymase inhibition in an animal model with nonalcoholic steatohepatitis which is involved in metabolic syndrome. Therefore, chymase inhibition may be useful for attenuating MMP-9 and TGF-β levels, in addition to reducing angiotensin II formation, and this function may provide powerful preventions of organ damages. In this review, we propose the significance of chymase as a target to prevent complications of metabolic syndrome.

Effect of sperminated pullulans on drug permeation through isolated rabbit cornea and determination of ocular irritation

The aim of this study was to investigate the effect of two sperminated pullulans (SP) with a different number of amino groups (SP-L, amino group content 0.124 mmol/g polymer; and SP-H, amino group content 0.578 mmol/g polymer) on the permeation of drugs through isolated rabbit corneas. Determination of corneal hydration levels and Draize eye tests were performed to assess the safety of SP both in vitro and in vivo. For 0.2% (w/v) SP-L and 0.2% (w/v) SP-H, the enhancement ratios (ERs) with dexamethasone of 1.34 and 1.42, respectively, were not statistically significant. For ofloxacin, tobramycin and sodium fluorescein, the ERs with 0.2% SP-L were 1.37, 2.02 and 2.12, respectively, and with 0.2% SP-H the ERs were 1.84, 4.69 and 6.87, respectively; these ERs were all statistically significant. Enhancement increased with increasing amino group content of the SP. The improved transcorneal drug absorption via the paracellular route indicated opening of the tight junctions in the corneal epithelium. Irritation tests indicated that 0.2% SP-L and 0.2% SP-H did not damage the corneal tissues.

Molecular characterization of suppression of hepatitis B virus transcription by hepatitis C virus core protein

To further elucidate the molecular mechanisms underlying the suppression of hepatitis B virus (HBV) expression by the hepatitis C virus (HCV) core protein, five molecular clones of HCV cDNA sequence containing the 5' noncoding (5'NC) and the core regions have been isolated from Chinese HBV- and HCV-coinfected patients. Sequence comparison and phylogenetic analysis showed that the HCV sequence cloned from coinfected individuals is indistinguishable from that identified in other patients. Cotransfection assay confirmed that the core protein expressed from one of the cloned sequence is capable of suppressing the expression of hepatitis B surface and e antigens (HBsAg and HBeAg, respectively). Deletion mapping revealed that the C-terminal hydrophobic region of the HCV. core is necessary for the suppression. Results from reporter assays demonstrated that HCV core protein interacts with the HBV C promoter and enhancer II elements and down-regulates the transcription of HBV as well as other cellular and heterologous viral genes in both hepatic and non-hepatic cell lines. Taken together, the findings suggest HCV core protein as a multifunctional negative regulator of transcription critically involved in the molecular interactions between HBV and HCV, and between HCV and the cell.

Distribution of pathogenic Yersinia enterocolitica in China

Yersinia enterocolitica (1,295 strains) was isolated from diarrhea patients, livestock, poultry, wild animals, insect vectors, food, and the environment. They were studied for epidemiology distribution using bacterial biochemical metabolism tests, their virulence genes, and pulsed-field gel electrophoresis (PFGE) sub-typing. The data showed that 416 of the 1,295 strains were pathogenic, where the pathogenic Chinese isolates were of serotypes O:3 and O:9. These two serotypes were found in livestock and poultry, with swine serving as the major reservoir. The geographic distribution of pathogenic isolates was significantly different, where most of the strains were isolated from the cold northern areas, whereas some serotype O:3 strains were recovered from the warm southern areas. By the analysis of the data of the Ningxia Hui Autonomous Region, we find the phenomenon of 'concentric circle distribution' around animal reservoirs and human habitation. The clustering of PFGE showed that the patterns of the pathogenic strains isolated from diarrhea patients were identical compared to those from the animals in the same area, thus, suggesting that the human infection originated from the animals.

Therapeutic vaccination against advanced pancreatic cancer by autologous dendritic cells pulsed with a MUC1 peptide: Preclinical results of a clinical phase I trial

e15652

Background: Pancreatic ductal adenocarcinoma has a particularly poor prognosis. Therefore, novel therapeutic strategies such as immunotherapy are required. The aim of the present phase I study was to evaluate the safety, immune responses and clinical activity of a vaccine based on autologous dendritic cells (DC) pulsed with a specific MUC1 peptide in advanced pancreatic cancer patients. Methods: Five patients who had pancreatic cancer ductal adenocarcinoma expressing MUC1 in stage of III/IV were enrolled to the clinical trial. Patients underwent leukapheresis to generate dendritic cells by culture in vitro with granulocyte macrophage colony-stimulating factor and interleukin-4 for 5 days. Dendritic cells were then pulsed overnight with MUC1 peptide (GVTSAPDTRPAPGSTAPPAH) and harvested for vaccination. Dendritic cells (3×106-6×106) were injected intradermally every 2 weeks for 3–4 times. Results: All patients remained with progressive disease. Four patients developed strong T-cell IFN-γ and Granzyme B Elispot responses to the vaccine. Most interestingly, the patient who was treated with the highest number of DC(6×106) had more number of CTL than other patients and showed delayed-type hypersensitivity responses at injection sites and this patient stopped application of the analgetics. Another patient with relapsed pancreatic cancer who had finished the 4 times of vaccination and then followed 6 times of chemotherapy with Gemcitabine had a surprisingly long term of survival of 12 month. No evidence of significant treatment related toxicity or auto-immunity was observed. Conclusions: This study showed the safety and clinical response of MUC1 peptide-pulsed dendritic cell therapy for patients with advanced pancreatic cancer. It confirms the capability of this DC vaccine to stimulate an immune response in patients with pancreatic cancer even in the presence of a large tumor burden. Dendritic cell therapy is recommended for further clinical studies in pancreatic cancer patients.

No significant financial relationships to disclose.

A novel recombinant tandem repeat DNA vaccine targeting at MUC1

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Background: Tandem repeat (TR) is the key epitope of mucin 1 (MUC1) for inducing cytotoxic T lymphocytes (CTL) to kill the tumor cells specifically. A novel recombinant TR DNA vaccine was constructed to study its induced immune responses. Methods: A recombinant human TR (rhTR) gene encoding a single TR polypeptide of MUC1 was synthesized and cloned into the multiple cloning sites of plasmid pcDNA3.1/Myc-his (+) A to construct the recombinant plasmid pcDNA3.1-TR/Myc-his (+) A (pTR plasmid). Expression of pTR plasmid was confirmed by transfection assay and Western blot analysis. C57BL/6 (H-2b) mice were immunized with pTR plasmid (n=15) by tibial muscle injection. Mice inoculated with the empty vector (EV group, n=15) and 0.9% NaCl solution (NS group, n=15) were used as vector and blank control respectively. Four weeks later, all mice were immunized again. Specific antibody detection and cytotoxic assay were used to evaluate the vaccine-induced TR specific immune responses. Results: DNA sequencing confirmed that the pTR plasmid was exactly constructed. Transfection assay and Western blot analysis found that the transfected COS7 cells expressed TR polypeptide of MUC1 48 hours after transfection. Cytotoxic assay showed that immunization with pTR plasmid into C57BL/6 mice resulted in more efficient induction of CTL specific cytolysis against TR polypeptide than that of EV group and NS group (p<0.01). Vaccine immunized mice had a higher equivalent concentration of anti-TR specific antibodies (2324μg/ml±238μg/ml) than that of EV group (1896μg/ml±533μg/ml, p<0.01) and NS group (1736μg/ml±142μg/ml, p<0.01). Conclusions: The novel recombinant TR DNA vaccine targeting at MUC1 was exactly constructed, immunization with which could induce TR specific CTL response and antibodies response in mice.

No significant financial relationships to disclose.