Characterization and Epitope Mapping of the Polyclonal Antibody Repertoire Elicited by Ricin Holotoxin-Based Vaccination

Ricin, one of the most potent and lethal toxins known, is classified by the Centers for Disease Control and Prevention (CDC) as a select agent. Currently, there is no available antidote against ricin exposure, and the most promising therapy is based on neutralizing antibodies elicited by active vaccination or that are given passively. The aim of this study was to characterize the repertoire of anti-ricin antibodies generated in rabbits immunized with ricin toxoid. These anti-ricin antibodies exhibit an exceptionally high avidity (thiocyanate-based avidity index, 9 M) toward ricin and an apparent affinity of 1 nM. Utilizing a novel tissue culture-based assay that enables the determination of ricin activity within a short time period, we found that the anti-ricin antibodies also possess a very high neutralizing titer. In line with these findings, these antibodies conferred mice with full protection against pulmonary ricinosis when administered as a passive vaccination. Epitope mapping analysis using phage display random peptide libraries revealed that the polyclonal serum contains four immunodominant epitopes, three of which are located on the A subunit and one on the B subunit of ricin. Only two of the four epitopes were found to have a significant role in ricin neutralization. To the best of our knowledge, this is the first work that characterizes these immunological aspects of the polyclonal response to ricin holotoxin-based vaccination. These findings provide useful information and a possible strategy for the development and design of an improved ricin holotoxin-based vaccine.     

Similar outcome for cryopreserved embryo transfer following GnRH-antagonist/GnRH-agonist, GnRH-antagonist/HCG or long protocol ovarian stimulation

The pregnancy rates after triggering of final oocyte maturation with gonadotrophin-releasing hormone (GnRH) agonist in GnRH-antagonist ovarian stimulation protocols are lower than those following triggering with human chorionic gonadotrophin (HCG). Furthermore, lower pregnancy rates following GnRH-antagonist protocols compared with long GnRH-agonist protocols have been reported. The differences might be due to an impact on oocyte number and quality or on the endometrium. If any stimulation protocol had a negative impact on oocyte quality, then further evidence of this effect would be observed following frozen-thawed embryo transfer originating from that stimulation cycle. The outcome of frozen-thawed embryo transfer was retrospectively analysed using the long protocol with triptorelin depot 3.75 mg (n = 215) or 0.1 mg/day (n = 83), or GnRH-antagonist protocol with either HCG (n = 69) or GnRH-agonist (n = 25) for final oocyte maturation. The outcomes measured were implantation rate, clinical pregnancy rate, ongoing pregnancy rate and embryo survival rate. All outcomes were similar in the four groups. It is concluded that the potential for frozen-thawed embryos to implant and develop following transfer is independent of the GnRH-analogue and the final oocyte maturation protocol used in the collection cycle. Lower IVF embryo transfer success using GnRH-antagonist/GnRH-agonist protocol does not appear to be related to an adverse effect on oocyte quality.     

Vascular smooth muscle cell-derived adiponectin: a paracrine regulator of contractile phenotype

Adiponectin is a cardioprotective adipokine derived predominantly from visceral fat. We recently demonstrated that exogenous adiponectin induces vascular smooth muscle cell (VSMC) differentiation via repression of mTORC1 and FoxO4. Here we report for the first time that VSMC express and secrete adiponectin, which acts in an autocrine and paracrine manner to regulate VSMC contractile phenotype. Adiponectin was found to be expressed in human coronary artery and mouse aortic VSMC. Importantly, siRNA knock-down of endogenous adiponectin in VSMC significantly reduced the expression of VSMC contractile proteins. Contractile protein deficiency was also observed in primary VSMC isolated from Adiponectin(-/-) mice. This deficiency could be rescued by culturing Adiponectin(-/-) VSMC in conditioned media from wild type (WT) VSMC. Moreover, the paracrine effect of VSMC-derived adiponectin was confirmed as adiponectin neutralizing antibody blocked the rescue. Overexpressed adiponectin also exerted paracrine effects on neighboring untransfected VSMC, which was also blocked by adiponectin neutralizing antibody. Interestingly, adiponectin expression was inducible by the PPARγ agonist rosiglitazone. Our data support an important role for VSMC-derived adiponectin in maintaining VSMC contractile phenotype, contributing to critical cardioprotective functions in the vascular wall. This article is part of a Special Issue entitled "Local Signaling in Myocytes".     

Effects of Aging Torque Controllers on Screw Tightening Force and Bacterial Micro-Leakage on the Implant-Abutment Complex

Aim: We assess the accuracy of torque controllers after several aging processes and the bacterial leakage on implant-abutment complexes (IAC). Methods: A total of 12 spring-type and 12 friction-type torque controllers and 48 IAC (24 conical and 24 hexagonal connections) were evaluated. Chemical, mechanical, temperature, and pressure-aging methods were applied individually to replicate clinical use. Torque controller accuracy was analyzed before and after aging using a calibrated gauge. To assess bacterial leakage, the IAC were suspended in a bacterial medium for 24 h. Direct Contact Test (DCT) and Polymerase Chain Reaction Test (RT-PCR) analyzed the infiltration of F. nucleatum and P. gingivalis into the IAC micro-gap. Results: A significant decrease in torque after 10 days of aging was found. The spring-type torque controller was affected the most, regardless of the aging method (P < 0.05). PCR results indicated that all groups exhibited significantly more bacterial leakage, regardless of the method used (P < 0.05). The conical IAC demonstrated more bacterial leakage of P. gingivalis compared with the hexagonal IAC (P = 0.07). DCT found bacterial growth in the IAC only before aging and was not identified after aging. Conclusion: Aging affects torque accuracy. A reduction in force was noticed after 10 days. The conical IAC exhibits more bacterial leakage, although this was not statistically significant.     

Maternal obesity and long-term neuropsychiatric morbidity of the offspring

Archives of Gynecology and Obstetrics - To evaluate the long-term pediatric neuropsychiatric morbidity of children born to obese patients. A population-based cohort analysis was performed comparing...     

Does the Cerebellum Implement or Select Geometries? A Speculative Note

The Cerebellum - During evolution, living systems, actively interacting with their environment, developed the ability, through sensorimotor contingencies, to construct functional spaces shaping...