Specific antigen/antibody interactions measured by force microscopy.

Molecular recognition between biotinylated bovine serum albumin and polyclonal, biotin-directed IG antibodies has been measured directly under various buffer conditions using an atomic force microscope (AFM). It was found that even highly structured molecules such as IgG antibodies preserve their specific affinity to their antigens when probed with an AFM in the force mode. We could measure the rupture force between individual antibody-antigen complexes. The potential and limitations of this new approach for the measurement of individual antigen/antibody interactions and some possible applications are discussed.     

Diffusion is capable of translating anisotropic apoptosis initiation into a homogeneous execution of cell death

Background  

Apoptosis is an essential cell death process throughout the entire life span of all metazoans and its deregulation in humans has been implicated in many proliferative and degenerative diseases. Mitochondrial outer membrane permeabilisation (MOMP) and activation of effector caspases are key processes during apoptosis signalling. MOMP can be subject to spatial coordination in human cancer cells, resulting in intracellular waves of cytochrome-c release. To investigate the consequences of these spatial anisotropies in mitochondrial permeabilisation on subsequent effector caspase activation, we devised a mathematical reaction-diffusion model building on a set of partial differential equations.     

Usefulness of 1,3 Beta-<Emphasis Type="SmallCaps">d</Emphasis>-Glucan Detection in non-HIV Immunocompromised Mechanical Ventilated Critically Ill Patients with ARDS and Suspected <Emphasis Type="Italic">Pneumocystis jirovecii</Emphasis> Pneumonia

Introduction

Pneumocystis jirovecii pneumonia (PCP) is a major cause of disease in immunocompromised individuals. Diagnosis is typically obtained by microscopy and/or PCR. For ambiguous PCR results, we evaluated the new biomarker 1,3-Beta-d-Glucan (BDG).

Methods

BDG serum levels were assessed and correlated to PCR results in immunosuppressed patients with ARDS.

Results

11 (22%) out of 50 patients had suspected PCP. APACHE II (26 vs. 24; p < 0.002), SOFA score (16 vs. 14; p < 0.010) and mortality rate (34 vs. 69% p < 0.004; 34 vs. 80% p < 0.003) were significantly altered in patients with positive (pPCR) and slightly positive (spPCR) PCJ PCR as compared to patients with no-PCP (nPCP). BDG levels were significantly lower in patients with nPCP (86; 30–315 pg/ml) than in patients with pPCR (589; 356–1000 pg/ml; p < 0.001) and spPCP (398; 297–516 pg/ml; p < 0.004) referring to the cutoff in this study for PCP of 275 pg/ml. An overall sensitivity (S) of 92% (95% CI 86–96%) and specificity (SP) of 84% (95% CI 79–85%) for PCP were found for the BDG Fungitell assay. In detail, S of 98% (95% CI 94–100%) and SP of 86% (95% CI 82–92%) for pPCP and S of 98% (95% CI 96–100%) and SP of 88% (95% CI 86–96%) for spPCO were found.

Conclusion

Serum BDG levels were strongly elevated in PCP, and the negative predictive value is high. BDG could be used as a preliminary test for patients with suspected PCP, especially in patients with slightly positive PCR results.

     

Untangling complex histories of genome mergings in high polyploids

Polyploidy, the duplication of entire genomes, plays a major role in plant evolution. In allopolyploids, genome duplication is associated with hybridization between two or more divergent genomes. Successive hybridization and polyploidization events can build up species complexes of allopolyploids with complicated network-like histories, and the evolutionary history of many plant groups cannot be adequately represented by phylogenetic trees because of such reticulate events. The history of complex genome mergings within a high-polyploid species complex in the genus Cerastium (Caryophyllaceae) is here untangled by the use of a network algorithm and noncoding sequences of a low-copy number gene. The resulting network illustrates how hybridization and polyploidization have acted as key evolutionary processes in creating a plant group where high-level allopolyploids clearly outnumber extant parental genomes.     

Significantly greater antioxidant anticancer activities of 2,3-dehydrosilybin than silybin

Silybin or silymarin extract has been used to treat liver diseases, and has now been entered into clinical trials for cancer treatment. Here, we compared antioxidant and anticancer activities between silybin and its oxidized form 2,3-dehydrosilybin (DHS). With IC50 at three-fold lower concentrations than silybin, DHS inhibited reactive oxygen species generation in glucose-glucose oxidase system and HepG2 cells. Compared with silybin, DHS elicited greater protection against H2O2-induced HepG2 cell death and galactosamine-induced liver injury in vivo. It is known that oxidants induce releases of metalloproteinases (MMP)-2,-9 which are responsible for invasive and metastasis potentials of transformed cells. DHS at 10 microM markedly inhibited MMP-2,-9 releases as well as invasiveness, while silybin at 90 microM had marginal effects. DHS but not silybin at 30 microM induced apoptosis and loss of mitochondrial membrane potentials. LD50 of DHS was five-fold lower than that of silybin. Our data suggest that DHS may be more useful therapeutically than silybin.     

2G12-Expressing B Cell Lines May Aid in HIV Carbohydrate Vaccine Design Strategies

The highly conserved cluster of high-mannose glycans on the HIV-1 envelope glycoprotein, gp120, has been highlighted as a target for neutralizing antibodies. 2G12, the first HIV-1 antiglycan neutralizing antibody described, binds with an unusual domain-exchanged structure that creates a high-affinity multivalent binding surface. It is an interesting challenge for rational vaccine design to generate immunogens capable of eliciting domain-exchanged 2G12-like responses. We recently showed that di-mannose recognition by the variable domains of 2G12 is independent of domain exchange but that exchange is critical for virus neutralization. Carbohydrate-based immunogens aimed at inducing 2G12-like antibodies may need to drive both di-mannose recognition and domain exchange through interactions with B cell receptors. Here we assessed the ability of such immunogens to activate mouse B cell lines displaying domain-exchanged wild-type 2G12 (2G12 WT), a non-domain-exchanged Y-shaped variant (2G12 I19R), and germ line 2G12 (2G12 gl). We show that several immunogens, including heat-killed yeast and bacteria, can activate both 2G12 WT and 2G12 I19R B cells. However, only discrete clusters of high-mannose glycans, as on recombinant forms of the HIV-1 envelope trimer and oligodendrons, activate 2G12 WT B cells. Furthermore, no immunogen tested activated 2G12 gl cells. Our results support the hypothesis that in order to drive domain exchange of an antimannose antibody response, a boost with an immunogen displaying discrete clusters of high-mannose glycans not recognized by conventional Y-shaped antibodies will be required. Additionally, a molecule capable of activating 2G12 gl cells might also be required. The results highlight broadly neutralizing antibody-expressing mouse B cells as potentially useful tools for carbohydrate immunogen screening.     

120 例初治、年轻、中高/ 高危弥漫大B细胞淋巴瘤的临床分析

目的:探讨初治、年轻、中高/高危弥漫大B细胞淋巴瘤(diffuse large B cell lymphoma,DLBCL)的临床特征、治疗措施及预后影响因素。方法:回顾性分析2006年1月至2014年5月军事医学科学院附属医院淋巴瘤科收治的年龄≤60岁、年龄调整的国际预后指数(aa IPI)评分≥2分的初治DLBCL病例,进行疗效及预后相关因素的分析。结果:共收集到资料完整的DLBCL病例120例,中位随访28(4-106)个月,3年PFS率53.25%,OS率61.52%。单因素分析结果显示B症状、治疗方案及近期疗效、自体移植对无进展生存(PFS)及总体生存(OS)率的影响有统计学意义。多因素分析结果显示治疗方案、自体造血干细胞移植是影响PFS、OS率的独立影响因素。结论:年轻、中高/高危DLBCL具有高度异质性,病理细胞来源、Ki-67等在本组病例中未见显著预后意义,有待临床进一步探索。     

Mitochondrial DNA structure and colony expansion dynamics of New Zealand fur seals (Arctocephalus forsteri) around Banks Peninsula

New Zealand fur seals are one of many pinniped species that survived the commercial sealing of the eighteenth and nineteenth centuries in dangerously low numbers. After the enforcement of a series of protection measures in the early twentieth century, New Zealand fur seals began to recover from the brink of extinction. We examined the New Zealand fur seal populations of Banks Peninsula, South Island, New Zealand using the mitochondrial DNA control region. We identified a panmictic population structure around Banks Peninsula. The most abundant haplotype in the area showed a slight significant aggregated structure. The Horseshoe Bay colony showed the least number of shared haplotypes with other colonies, suggesting a different origin of re-colonisation of this specific colony. The effective population size of the New Zealand fur seal population at Banks Peninsula was estimated at approximately 2500 individuals. The exponential population growth rate parameter for the area was 35, which corresponds to an expanding population. In general, samples from adjacent colonies shared 4.4 haplotypes while samples collected from colonies separated by between five and eight bays shared 1.9 haplotypes. The genetic data support the spill-over dynamics of colony expansion already suggested for this species. Approximate Bayesian computations analysis suggests re-colonisation of the area from two main clades identified across New Zealand with a most likely admixture coefficient of 0.41 to form the Banks Peninsula population. Approximate Bayesian computations analysis estimated a founder population size of approximately 372 breeding individuals for the area, which then rapidly increased in size with successive waves of external recruitment. The population of fur seals in the area is probably in the late phase of maturity in the colony expansion dynamic.     

Inhibition of vibrio anguillarum by Pseudomonas fluorescens AH2, a possible probiotic treatment of fish

To study the possible use of probiotics in fish farming, we evaluated the in vitro and in vivo antagonism of antibacterial strain Pseudomonas fluorescens strain AH2 against the fish-pathogenic bacterium Vibrio anguillarum. As iron is important in virulence and bacterial interactions, the effect of P. fluorescens AH2 was studied under iron-rich and iron-limited conditions. Sterile-filtered culture supernatants from iron-limited P. fluorescens AH2 inhibited the growth of V. anguillarum, whereas sterile-filtered supernatants from iron-replete cultures of P. fluorescens AH2 did not. P. fluorescens AH2 inhibited the growth of V. anguillarum during coculture, independently of the iron concentration, when the initial count of the antagonist was 100 to 1, 000 times greater that of the fish pathogen. These in vitro results were successfully repeated in vivo. A probiotic effect in vivo was tested by exposing rainbow trout (Oncorynchus mykiss Walbaum) to P. fluorescens AH2 at a density of 10(5) CFU/ml for 5 days before a challenge with V. anguillarum at 10(4) to 10(5) CFU/ml for 1 h. Some fish were also exposed to P. fluorescens AH2 at 10(7) CFU/ml during the 1-h infection. The combined probiotic treatment resulted in a 46% reduction of calculated accumulated mortality; accumulated mortality was 25% after 7 days at 12 degrees C in the probiotic-treated fish, whereas mortality was 47% in fish not treated with the probiont.