Toll-like receptor-3 (TLR3) recognizes dsRNA and initiates an innate immune response through the formation of a signaling unit (SU) composed of 1 dsRNA and 2 TLR3 molecules. We report the crystal structure of human TLR3 ectodomain (TLR3ecd) in a quaternary complex with three neutralizing Fab fragments. Fab15 binds an epitope that overlaps the C-terminal dsRNA binding site and in biochemical assays blocks the interaction of TLR3ecd with dsRNA, thus directly antagonizing TLR3 signaling through inhibition of SU formation. In contrast, Fab12 and Fab1068 bind TLR3ecd at sites distinct from the N and C-terminal regions that interact with dsRNA and do not inhibit minimal SU formation with short dsRNA. Molecular modeling based on the co-structure rationalizes these observations by showing that both Fab12 and Fab1068 prevent lateral clustering of SUs along the length of the dsRNA ligand. This model is further supported by cell-based assay results using dsRNA ligands of lengths that support single and multiple SUs. Thus, their antagonism of TLR3 signaling indicates that lateral clustering of SUs is required for TLR3 signal transduction.

OBJECTIVES: To investigate whether (18)F- FDG uptake can be applied in dosimetry to facilitate the rapid and accurate evaluation of individual radiation doses after a nuclear accident. METHODS: Forty-eight Tibetan minipigs were randomised into a control group (n = 3) and treatment groups (n = 45).(18)F-FDG combined positron-emission tomography and computed tomography (PET/CT) were carried out before total body irradiation (TBI) and at 6, 24 and 72 h after receiving TBI doses ranging from 1 to 11 Gy. Spleen tissues and blood samples were also collected for histological examination, apoptosis and blood analysis. RESULTS: Mean standardised uptake values (SUVs) of the spleen showed significant differences between the experimental and the control groups. Spleen SUV at 6 h post-irradiation showed significant correlation with radiation dose; Spearman's correlation coefficient was 0.97 (P < 0.01). Histological observations showed that damage to the splenic lymphocyte became more severe with an increase in the radiation dose. Moreover, apoptosis was one of the major routes of splenic lymphocyte death, which was also confirmed by flow cytometry analysis. CONCLUSIONS: In the Tibetan minipig model, radiation doses have a close relationship with the (18)F-FDG uptake of the spleen. This finding suggests that (18)F-FDG PET/CT may be useful for the rapid detection of individual radiation doses. KEY POINTS: • The spleen responds rapidly and is very sensitive to total body irradiation. • In Tibetan minipigs, the radiation dose is closely related to the 18F-FDG uptake of the spleen. • 18F-FDG PET/CT may be useful for the prediction of individual radiation doses.

There are a number of proteins whose active forms are non-covalent multichain complexes. Therapeutic intervention involving such complexes has been proposed through the use of muteins to form heterostructures. These resulting structures would either not be recognized by receptors or would be inactive competitive inhibitors to wild-type (wt) proteins. We have used tumor necrosis factor-α (TNF-α) to establish that it is possible to use mass spectrometry to monitor the non-covalent solution structure of therapeutically relevant proteins and correlate the results with binding data. Mass spectrometry is shown to be able to directly monitor the state of the solution complexes to within 5 Da errors mass accuracy of theoretical mass at 50 kDa, as well as to resolve homocomplex from heterocomplex. Furthermore, it was determined that perturbation of the TNF-α complex, at or below pH 4.0, results in monomers that cannot reform into the multimeric complex, and the resulting protein solution can no longer bind to an anti-TNF-α antibody. Dissociation and re-association of the trimer was possible with the use of dimethyl sulfoxide at pH 5.5 and allowed for the resulting detection of both homotrimer and heterotrimer in solution with no impact on antibody binding. This work demonstrates that mass spectrometric techniques offer a means to monitor native solution interactions of non-covalent complexes and to differentiate multiple complexes from each other in solution. This method has applicability in the biopharmaceutical arena for monitoring engineering non-covalent drug complexes for the purpose of altering biological activity. Copyright © 2012 John Wiley & Sons, Ltd.

Agrobacterium tumefaciens-mediated transformation of cotton embryogenic calli (EC) was enhanced by choosing appropriate EC and improving efficiency of coculture, selection cultivation, and plant regeneration. The binary vector pBI121 (containing a neomycin phosphotransferase II gene npt-II as a selection marker and a uidA gene as a reporter gene) was used to research transformation efficiency. After 48 h cocultivation, the number of β-glucuronidase (GUS)-positive calli characterized by yellow, loose, and fine-grained EC was twofold greater than that of gray, brown, and coarse granule EC. It indicated that the efficiency of transient transformation was affected by EC morphology. Transient transformation efficiency also was improved by cocultivation on the medium by adding 50 mg/L acetosyringone at 19°C for 48 h. Subculturing EC on the selection medium with low cell density increased the production of kanamycin-resistant (Km-R) calli lines. From an original 0.3 g EC, an average of 20 Km-R calli lines were obtained from a selection dish, and the GUS-positive rate of Km-R clones was 81.97%. A large number of normal plants were rapidly regenerated on the differentiation medium with dehydration treatments, and the GUS-positive rate of regeneration plants was about 72.6%. Polymerase chain reaction analysis of GUS-positive plantlets revealed a 100% positive detection rate for neomycin phosphotransferase II gene and gus gene. Southern blot of transgenic plants regenerated from different Km-R calli lines demonstrated that the target gene, mostly with the low copy number, was integrated into the cotton genome.

Summary.  Tumour necrosis factor-α (TNF-α) plays a pivotal role in hepatitis B virus (HBV) clearance and host immune response determining the chronicity of HBV infection. However, studies of the association between TNF-α-857 polymorphism and chronic HBV infection have reported conflicting results. So a meta-analysis was carried out to draw a more precise conclusion. Pubmed (January, 1966-March, 2011) and the China Biological Medicine Database (January, 1978-March, 2011) were searched using the keywords TNF-α gene polymorphism in combination with HBV infection without language restriction. Fourteen studies including 4929 chronic HBV infection cases and 2702 controls describing the C857T genotype were included in the meta-analysis. All fourteen studies focussed on an Asian population. The overall meta-analysis suggested that TNF-α-857T allele reduced the risk of chronic HBV infection in the Asian population (OR = 0.82, 95% CI: 0.71-0.95, P = 0.008) when compared with a spontaneously recovered population. In the sensitivity analyses of the groups obeying Hardy-Weinberg equilibrium (HWE), without the largest study population and without the smallest study population, a similar association was revealed (OR = 0.81, 95% CI: 0.68-0.98, P = 0.043; OR = 0.77, 95% CI: 0.68-0.87, P = 0.0001; OR = 0.81, 95% CI: 0.70-0.95, P = 0.009, respectively). However, when compared with a healthy population, no significant association was found in the Asian population in all groups. So, we draw the conclusion that the TNF-α-857T allele reduces the risk of chronic HBV infection in this Asian population.

Summary.  Tumour necrosis factor-α (TNF-α) plays a pivotal role in viral clearance and host immune response to hepatitis B virus (HBV) infection, of which the production capacity in individuals is demonstrated to be influenced by a single nucleotide polymorphism within the promoter region of TNF-α genes. However, there have been conflicting results reported in previous studies on TNF-α-238 and TNF-α-863 gene promoter polymorphisms in chronic HBV infection. To derive a more precise estimation of their relationship, we searched Pubmed (January, 1966-August, 2010) and China Biological Medicine Database (January, 1978-August, 2010) and carried out a meta-analysis involving nineteen studies that included 5245 chronic HBV infection cases and 3181 controls describing G238A genotypes, and eleven studies totalling 3576 cases and 2044 controls describing C863A genotypes. The overall meta-analysis did not suggest significant associations of TNF-α-238 and TNF-α-863 gene promoter polymorphisms with chronic HBV infection. However, in subgroup analysis by ethnicity, it indicated that TNF-α-238A allele carriers (GA + AA) in European populations had an increased risk of developing chronic HBV infection (OR = 2.22, 95% CI: 1.07-4.58, P = 0.032; OR = 4.46, 95% CI: 1.75-11.38, P = 0.002, respectively), when compared with spontaneous recovered and healthy populations, respectively. However, no significant associations were found in Asian populations in all genetic models. So, we draw the conclusion that the TNF-α-238A allele may increase the risk of chronic HBV infection in European populations.

The purpose of this study was to determine the time-dose-effect of total body X-ray irradiation on lymphocytes in lymph nodes and peripheral blood in Tibet minipigs. Forty-eight Tibet minipigs were assigned into 6 groups including 5 experimental groups with 9 and the control group with 3. The minipigs in experimental groups were subjected to a total body X-ray irradiation of 2, 5, 8, 11, and 14 Gy respectively. Lymph nodes and peripheral blood samples were collected at 6, 24 and 72 hours after X-ray exposure and received histological microscopy examination and apoptosis analysis. Histology observation showed that the number of lymphocytes decreased within the lymph nodes with the increase of radiation doses and exposure time. The observation of transmission electron microscopy (TEM) showed typical apoptotic cells below 11 Gy while at 14 Gy necrotic cells were dominant. The apoptotic rate of lymphocytes in the lymph nodes was positively correlated with radiation dose in the range of 2-11 Gy, and reached the maximal level (39.4 ± 2.8) at 24 hours after 11 Gy irradiation, followed by a decrease in the apoptotic rate, but still higher than that of the control group. The number of lymphocytes in the peripheral blood samples was decreased significantly by increasing of the radiation dose and exposure time. We conclude that early damage of lymphocytes by total body X-ray irradiation is dose and time dependent below 11 Gy and before 24 hours post irradiation, and that the dosage of irradiation less than 11 Gy induced apoptosis, whereas the dose at 14 Gy resulted in necrosis in lymphocytes of the lymph nodes.

DNMT3A mutations are associated with poor prognosis in acute myeloid leukemia (AML), but the stability of this mutation during the clinical course remains unclear. In the present study of 500 patients with de novo AML, DNMT3A mutations were identified in 14% of total patients and in 22.9% of AML patients with normal karyotype. DNMT3A mutations were positively associated with older age, higher WBC and platelet counts, intermediate-risk and normal cytogenetics, FLT3 internal tandem duplication, and NPM1, PTPN11, and IDH2 mutations, but were negatively associated with CEBPA mutations. Multivariate analysis demonstrated that the DNMT3A mutation was an independent poor prognostic factor for overall survival and relapse-free survival in total patients and also in normokaryotype group. A scoring system incorporating the DNMT3A mutation and 8 other prognostic factors, including age, WBC count, cytogenetics, and gene mutations, into survival analysis was very useful in stratifying AML patients into different prognostic groups (P <.001). Sequential study of 138 patients during the clinical course showed that DNMT3A mutations were stable during AML evolution. In conclusion, DNMT3A mutations are associated with distinct clinical and biologic features and poor prognosis in de novo AML patients. Furthermore, the DNMT3A mutation may be a potential biomarker for monitoring of minimal residual disease.

Objective: In order to overcome the defects of chemical hydrolysis approach to prepare glucosamine, an enzymatic hydrolysis method was developed. Methods: Glucosamine was prepared by hydrolyzing chitosan, employing α-amylase initially, and subsequently, glucoamylase. Results: The optimal hydrolyzing conditions were as follows: reaction time, 4 h; pH, 5.0; temperature, 50 °C; and, α-amylase, 80 U/g for the initial reaction. Subsequently, glucoamylase was added in the presence of α-amylase. The optimal reaction conditions were found to be: reaction time, 8 h; pH, 4.5; temperature, 55 °C; and, glucoamylase, 4000 U/g. The hydrolysates were subject to filtrating, concentrating to about 20%(w/w), precipitating with five volumes of ethanol, and drying at 60 °C for 2 h. The content and the yield of glucosamine in the dried precipitate were 91.3%(w/w) and 86.2%(w/w), respectively. Conclusions: The method developed in this study is a promising option in the preparation of glucosamine.

Background:Angiogenic factors have an essential role in normal and pathologic angiogenesis. However, the clinical implication of angiogenic factor expression in myelodysplastic syndromes (MDS) remains unclear.Methods:In this study, we sought to investigate the prognostic impact of the expression of genes encoding angiopoietin-1 (Ang-1), Ang-2, the receptor Tie2, vascular endothelial growth factor-A (VEGF-A) and VEGF-C in the bone marrow (BM) in 208 patients with newly diagnosed primary MDS.Results:BM Ang-1 expression was significantly higher in MDS patients, especially those with higher-risk subtypes, than in normal controls. With a median follow-up time of 32.9 months, the disease transformed to acute leukaemia more frequently in the patients bearing higher Ang-1 expression than in those with lower expression (31.5% vs 18.6%, P=0.023). The MDS patients with higher Ang-1 expression had shorter overall survival than those with lower expression (median 20.8±4.5 months vs 63.3±17.8 months, P<0.001). Multivariate analyses showed that higher Ang-1 expression was an independent unfavourable prognostic factor for overall survival. There was no impact of the expression of other angiogenic factors on survival.Conclusion:BM Ang-1 expression may serve as a new biomarker to predict clinical outcome in MDS patients.British Journal of Cancer advance online publication, 30 August 2011; doi:10.1038/bjc.2011.340 www.bjcancer.com.