An electrostatic/hydrogen bond switch as the basis for the specific interaction of phosphatidic acid with proteins

Phosphatidic acid (PA) is a minor but important phospholipid that, through specific interactions with proteins, plays a central role in several key cellular processes. The simple yet unique structure of PA, carrying just a phosphomonoester head group, suggests an important role for interactions with the positively charged essential residues in these proteins. We analyzed by solid-state magic angle spinning 31P NMR and molecular dynamics simulations the interaction of low concentrations of PA in model membranes with positively charged side chains of membrane-interacting peptides. Surprisingly, lysine and arginine residues increase the charge of PA, predominantly by forming hydrogen bonds with the phosphate of PA, thereby stabilizing the protein-lipid interaction. Our results demonstrate that this electrostatic/hydrogen bond switch turns the phosphate of PA into an effective and preferred docking site for lysine and arginine residues. In combination with the special packing properties of PA, PA may well be nature's preferred membrane lipid for interfacial insertion of positively charged membrane protein domains.     

Immunogenicity and safety assessment of the Cuban recombinant hepatitis B vaccine in healthy adults.

Manufactures of biotechnological/biological products (including vaccines) frequently make changes to manufacturing processes of products both during development and after approval. In our case, a non-inferiority bridging study was carried out to demonstrate that changes in the production plant facilities of Cuban recombinant hepatitis B vaccine, Heberbiovac HB, did not affect the safety and immunogenicity of the vaccine. This controlled, randomized, doubled-blinded trial included 501 volunteers, aged between 20 and 64, who were given three doses of vaccine (20 microg HBsAg/mL) at month 0, 1, and 2. Four lots were evaluated (three corresponding to the new production facilities and a control one produced in the older facilities). One month after the third dose, were observed protective levels of anti-HBsAg in 97% of the subjects that concluded the study with a geometric mean antibody titer (GMT) of 931.18 IU/L. Normal values of body mass index (BMI), the younger ages, and being a female, were significantly related to a good antibody response. The vaccine was well tolerated. Pain at the injection site was the most commonly reported symptom. We conclude that Heberbiovac HB vaccine maintains its characteristics after the modifications carried out in the production plant facilities and both, lot obtained in previous facilities and in the new ones, are comparable in terms of safety and immunogenicity.     

Carbon-activated gas filtration during in vitro culture increased pregnancy rate following transfer of in vitro-produced bovine embryos

Many environmental conditions for in vitro embryo production (IVP) systems for cattle have been relatively standardised, e.g. media composition, temperature, pH, water quality, and atmospheric composition. However, little attention has been paid to the quality of ambient laboratory air and the gas environment in incubators. Although a few studies have examined the effects of chemical air contamination on IVP of human embryos, there are no published accounts for domestic animal embryos. Therefore, this study investigated the effects of an intra-incubator carbon-activated air filtration system (CODA) during in vitro culture (IVC) on embryonic development and subsequent pregnancy rate of bovine embryos. Immature cumulus-oocyte-complexes (COCs) were obtained twice-weekly by ultrasonic-guided transvaginal oocyte aspiration. The COCs were matured in TCM199/FCS/LH/FSH, fertilized with frozen-thawed Percoll-separated semen, and subsequently cultured for 7 day in SOFaaBSA. Day 7 embryos were transferred either fresh or frozen/thawed. The experimental design was a 2 x 2 factorial; presumptive zygotes were placed either in a conventional CO(2)-O(2)-N(2) incubator (Control group) or in an identical CO(2)-O(2)-N(2) incubator with a CODA intra-incubator air purification unit (CODA group) for IVC. The embryo production rate at Day 7 was not affected by the CODA air purification unit (23.4 and 24.7% morulae and blastocysts per oocyte for control and CODA, respectively) nor was there any significant effect on embryo stage or quality. However, the pregnancy rate was improved (P=0.043) for both fresh (46.3% versus 41.0%) and frozen/thawed embryos (40.8% versus 35.6%). In conclusion, atmospheric purification by the CODA intra-incubator air purification unit significantly increased pregnancy rate following transfer of in vitro-produced bovine embryos.     

Quantifying multiple pressure interactions affecting populations of a recreationally and commercially important freshwater fish

The expanding human global footprint and growing demand for freshwater have placed tremendous stress on inland aquatic ecosystems. Aichi Target 10 of the Convention on Biological Diversity aims to minimize anthropogenic pressures affecting vulnerable ecosystems, and pressure interactions are increasingly being incorporated into environmental management and climate change adaptation strategies. In this study, we explore how climate change, overfishing, forest disturbance, and invasive species pressures interact to affect inland lake walleye (Sander vitreus) populations. Walleye support subsistence, recreational, and commercial fisheries and are one of most sought‐after freshwater fish species in North America. Using data from 444 lakes situated across an area of 475 000 km² in Ontario, Canada, we apply a novel statistical tool, R‐INLA, to determine how walleye biomass deficit (carrying capacity—observed biomass) is impacted by multiple pressures. Individually, angling activity and the presence of invasive zebra mussels (Dreissena polymorpha) were positively related to biomass deficits. In combination, zebra mussel presence interacted negatively and antagonistically with angling activity and percentage decrease in watershed mature forest cover. Velocity of climate change in growing degree days above 5°C and decrease in mature forest cover interacted to negatively affect walleye populations. Our study demonstrates how multiple pressure evaluations can be conducted for hundreds of populations to identify influential pressures and vulnerable ecosystems. Understanding pressure interactions is necessary to guide management and climate change adaptation strategies, and achieve global biodiversity targets.     

Diagnosis of takotsubo cardiomyopathy is increasing over time in patients presenting as ST-elevation myocardial infarction

Background

Takotsubo cardiomyopathy often presents with the clinical signs of ST-elevation myocardial infarction (STEMI). The increase in scientific publications addressing this relatively rare condition may result in higher awareness and diagnosis of takotsubo cardiomyopathy.

Aim

To assess the observed prevalence per year of takotsubo cardiomyopathy in a large registry of patients with STEMI, during a 12-year inclusion period.

Method

All patients presenting with STEMI at a large regional cardiology clinic were entered into a database (n = 8,413, mean age 63 ± 13 years). Takotsubo cardiomyopathy was diagnosed in 42 patients (0.5?%). Years of evaluation were defined as ‘early years’ (January 2002 to December 2007; n = 4350) and ‘later years’ (January 2008 to December 2013). Multivariable analyses were performed to adjust for differences in demographical and clinical variables.

Results

In later years, the age of STEMI patients was slightly higher (64 ± 13 vs. 63 ± 13 years, p < 0.001), with more patients with clinical symptoms of shock (10 vs. 7?%, p < 0.001) or a history of percutaneous coronary intervention or hypertension (10 vs. 8?%, p = 0.001 and 37 vs. 34?%, p < 0.001). Smoking and a positive family history were less often observed during later years (39 vs. 46?%, p < 0.001 and 37 vs. 42?% p < 0.001). Patients with takotsubo cardiomyopathy were more often female (81 vs. 27?%, p = 0.001). Takotsubo cardiomyopathy was more often diagnosed in the later period (0.7 vs. 0.3?%, OR 2.4, 95?% CI 1.2–4.6, p = 0.009). The higher prevalence of takotsubo cardiomyopathy in recent years remained significant after adjustment for differences in patient characteristics (OR 2.1, 95?% CI 1.1–4.3).

Conclusion

Takotsubo cardiomyopathy is currently more often diagnosed in patients with STEMI compared with in earlier years. This is probably due to the increased scientific and clinical awareness among doctors, but the prevalence is still low.

     

我国两株登革2型病毒5′和3′端非编码区序列测定及二级结构分析

 为测定我国两株临床症状、乳鼠神经毒力不同的登革 2型病毒流行株 5′和 3′端非编码区序列 (untranslated region,UTR) ,分析二级结构差异与毒力变化的关系 ,分别从 D2 - 0 4、D2 - 44株感染的 C6/ 36细胞及鼠脑中提取总 RNA.以该 RNA为模板 ,利用 RACE法 ,分别扩增了 D2 - 0 4、D2 -44株的 5′和 3′末端 c DNA片段 .将其分别与 p GEM- T载体连接得到重组质粒 ,测定上述 c DNA插入片段的序列 .用 RNAdraw软件预测 D2 - 0 4、D2 - 44株 5′和 3′端非编码区的二级结构 .D2 - 0 4、D2 -44株 5′端和 3′端非编码区分别有 96和 454个核苷酸 .其中 5′非编码区 59位 C(D2 - 0 4 )→T(D2 -44 ) ,使 D2 - 44二级结构稳定性下降 ;3′端非编码区有 1 5个核苷酸不同 ,其中 T(355)→ A,T(32 6)→ G引起了所在位置二级结构自由能变化 ,且分别位于两个保守序列区 (conserved sequence,CS)CS1、CS2 A.这些位点变化可能与毒力有关 .     

The Value of Intraoperative Near-Infrared Fluorescence Imaging Based on Enhanced Permeability and Retention of Indocyanine Green: Feasibility and False-Positives in Ovarian Cancer

Objective

In ovarian cancer, two of the most important prognostic factors for survival are completeness of staging and completeness of cytoreductive surgery. Therefore, intra-operative visualization of tumor lesions is of great importance. Preclinical data already demonstrated tumor visualization in a mouse-model using near-infrared (NIR) fluorescence imaging and indocyanine green (ICG) as a result of enhanced permeability and retention (EPR). The aim of this study was to determine feasibility of intraoperative ovarian cancer metastases imaging using NIR fluorescence imaging and ICG in a clinical setting.

Methods

Ten patients suspected of ovarian cancer scheduled for staging or cytoreductive surgery were included. Patients received 20 mg ICG intravenously after opening the abdominal cavity. The mini-FLARE NIR fluorescence imaging system was used to detect NIR fluorescent lesions.

Results

6 out of 10 patients had malignant disease of the ovary or fallopian tube, of which 2 had metastatic disease outside the pelvis. Eight metastatic lesions were detected in these 2 patients, which were all NIR fluorescent. However, 13 non-malignant lesions were also NIR fluorescent, resulting in a false-positive rate of 62%. There was no significant difference in tumor-to-background ratio between malignant and benign lesions (2.0 vs 2.0; P=0.99).

Conclusions

This is the first clinical trial demonstrating intraoperative detection of ovarian cancer metastases using NIR fluorescence imaging and ICG. Despite detection of all malignant lesions, a high false-positive rate was observed. Therefore, NIR fluorescence imaging using ICG based on the EPR effect is not satisfactory for the detection of ovarian cancer metastases. The need for tumor-specific intraoperative agents remains.

Trial Registration

ISRCTN Registry ISRCTN16945066     

Peroxidative metabolism of benzidine derivatives by Salmonella typhimurium

Benzidine and several derivatives are activated to mutagenic species in an H2O2-dependent Ames test system. Optical and electron paramagnetic resonance (EPR) spectroscopy are employed in studies of the H2O2-dependent oxidation of benzidine and 3,5,3',5'-tetramethylbenzidine (TMB) catalyzed by intact bacteria, and provide direct evidence for peroxidase activity in Salmonella typhimurium. The acetylase-proficient Ames tester strain TA98 and its acetylase-deficient derivative TA98/1,8-DNP6 are equally responsive to H2O2-dependent mutagenicity; enzymatic acetylation appears not to be involved in activation of benzidine, in this system. The H2O2-dependent mutagenicity of benzidine and oxidation of TMB are observed when the assays are carried out in acetate buffer (pH 5.5), but not in 2-[N-morpholino]ethane sulfonic acid (MES) buffer, at the same pH. This difference is interpreted in terms of the effects of these buffers on the intracellular pH of the bacteria. The H2O2-dependent mutagenicity of several benzidine congeners is also described.     

Inhibitory action of spermidine on formyl-methionyl-leucyl-phenylalanine stimulated inositol phosphate production in human neutrophils

The effect of the polyamine, spermidine, on formyl-methionyl-leucyl-phenylalanine stimulated hydrolysis of polyphosphoinositides was examined in purified human neutrophils by measurement of inositol phosphate production from radioactively labelled inositol. Spermidine inhibited formyl-methionyl-leucyl-phenylalanine stimulated inositol phosphate production by neutrophil in a dose dependent manner. Inhibition of formyl-methionyl-leucyl-phenylalanine stimulated inositol phosphate accumulation by spermidine was maximal at 10 microM and the IC50 value for this effect was 4.2 microM spermidine. This action of spermidine, thought to be mediated by a membrane component other than phospholipase C, may reflect a control mechanism modulating the response of the polyphosphoinositide system.     

Murine monoclonal antibody against aldosterone: production, characterization and use for enzymoimmunoassay

Hybridomas secreting monoclonal antibodies to aldosterone were obtained by fusion of myeloma cells and spleen cells from Balb/c mice immunized with aldosterone-3-carboxylmethyloxime-bovine serum albumin. A monoclonal antibody was purified from ascites fluid and characterized. An affinity constant of 1.61 x 10(9) M-1 has been measured and no cross-reactivity with tetrahydroaldosterone (THA), cortisol, cortisone, corticosterone, deoxycorticosterone (DOC), dehydroepiandrosterone (DHA), progesterone and estrone, could be detected. A peroxidase conjugated-antibody (1.5 mole of enzyme per mole of antibody) was obtained and used for microwell enzyme immunoassay and Immun-Blot assay. The high affinity and specificity of this antibody should make the direct determination of aldosterone in biological fluids possible at concentrations as low as 5 x 10(-10) M.