Doubly Bridged Anthracenes: Blue Emitters for OLEDs.

The photooxidative stability of a series of doubly bridged anthracenes was evaluated after their preparation via twofold macrocyclization of a bis(resorcinyl)anthracene. Lightfastness correlates with the energy levels of the highest occupied molecular orbital (HOMO), resulting in superior stability of the tetraesters compared to the tetraethers. The lengths and steric demand of the linker only plays a minor role for the ester-based compounds, which can be prepared in reasonable yields and thus tested in proof-of-concept organic light-emitting diodes. Double ester-bridging allows deep blue electro-luminescence, highlighting the importance of the choice of the functional groups used for macrocyclization.

Diphtheria toxin activates ribotoxic stress and NLRP1 inflammasome-driven pyroptosis.

The ZAKα-driven ribotoxic stress response (RSR) is activated by ribosome stalling and/or collisions. Recent work demonstrates that RSR also plays a role in innate immunity by activating the human NLRP1 inflammasome. Here, we report that ZAKα and NLRP1 sense bacterial exotoxins that target ribosome elongation factors. One such toxin, diphtheria toxin (DT), the causative agent for human diphtheria, triggers RSR-dependent inflammasome activation in primary human keratinocytes. This process requires iron-mediated DT production in the bacteria, as well as diphthamide synthesis and ZAKα/p38-driven NLRP1 phosphorylation in host cells. NLRP1 deletion abrogates IL-1ß and IL-18 secretion by DT-intoxicated keratinocytes, while ZAKα deletion or inhibition additionally limits both pyroptotic and inflammasome-independent non-pyroptotic cell death. Consequently, pharmacologic inhibition of ZAKα is more effective than caspase-1 inhibition at protecting the epidermal barrier in a 3D skin model of cutaneous diphtheria. In summary, these findings implicate ZAKα-driven RSR and the NLRP1 inflammasome in antibacterial immunity and might explain certain aspects of diphtheria pathogenesis.

P38 kinases mediate NLRP1 inflammasome activation after ribotoxic stress response and virus infection.

Inflammasomes integrate cytosolic evidence of infection or damage to mount inflammatory responses. The inflammasome sensor NLRP1 is expressed in human keratinocytes and coordinates inflammation in the skin. We found that diverse stress signals induce human NLRP1 inflammasome assembly by activating MAP kinase p38: While the ribotoxic stress response to UV and microbial molecules exclusively activates p38 through MAP3K ZAKα, infection with arthropod-borne alphaviruses, including Semliki Forest and Chikungunya virus, activates p38 through ZAKα and potentially other MAP3K. We demonstrate that p38 directly phosphorylates NLRP1 and that serine 107 in the linker region is critical for activation. NLRP1 phosphorylation is followed by ubiquitination of NLRP1PYD, N-terminal degradation of NLRP1, and nucleation of inflammasomes by NLRP1UPA-CARD. In contrast, activation of NLRP1 by nanobody-mediated ubiquitination, viral proteases, or inhibition of DPP9 was independent of p38 activity. Taken together, we define p38 activation as a unifying signaling hub that controls NLRP1 inflammasome activation by integrating a variety of cellular stress signals relevant to the skin.

Theory of cyclic voltammetry in random arrays of cylindrical microelectrodes applied to carbon felt electrodes for vanadium redox flow batteries.

In order to quantitatively investigate the kinetic performance and the pore size distribution of carbon felt electrodes for the application in vanadium redox flow batteries, the theory of cyclic voltammetry (CV) is derived for a random network of cylindrical microelectrodes on the base of convolutive modeling. In this context we present an algorithm based on the use of a modified Talbot contour for inverse Laplace transformation, providing the mass transfer functions required for the calculation of the CV responses in external cylindrical finite diffusion space. First-order homogenous chemical kinetics preceding and/or following the electrochemical reactions are implemented in this algorithm as well. The VO2+ oxidation is investigated as model reaction at pristine and electrochemically aged commercial carbon felt electrodes. A fit of simulated data to experimental data clearly shows that an electrochemical aging predominantly affects the kinetics of the electron transfer reaction and that internal electrode surfaces and pore size distributions remain constant. The estimated pore size distributions are in excellent agreement with porosimetry measurements, validating our theory and providing a new strategy to determine electrode porosities and electrode kinetics simultaneously via CV.

Impact of serum estradiol levels on the implantation rate of cleavage stage cryopreserved-thawed embryos transferred in programmed cycles with exogenous hormonal replacement.

PURPOSE: To investigate the impact of late follicular phase serum estradiol (E2) levels on implantation and pregnancy outcomes of cleavage stage cryopreserved/thawed embryos transferred in programmed cycles with exogenous hormonal replacement. METHODS: Retrospective cohort analysis of IVF patients with transfer of cryopreserved-thawed day-3 embryos in E2 and progesterone (P4) supplemented cycles (n = 208 cycles). MAIN OUTCOME MEASURES: implantation and pregnancy rates according to late follicular phase serum E2 levels and early secretory phase E2/P4 ratios. RESULTS: Logistic regression performed for embryo implantation and for pregnancy outcome in relation to E2 (day 15), P4 (day 15 and 16), before (crude analysis) and after adjustment (adjusted analysis) for baseline characteristics (including age, BMI, serum basal cycle day 3 FSH levels, embryo quality, endometrial lining thickness) showed no significant association. Similarly, ROC analysis showed no impact of cycle day 16 E2/P4 ratio. CONCLUSIONS: Neither late follicular phase serum E2 nor the early E2/P4 ratio were able to predict implantation or pregnancy outcome of day-3 cryopreserved-thawed embryos transferred in artificially programmed cycles.

Utility of the national embryo morphology data collection by the Society for Assisted Reproductive Technologies (SART): correlation between day-3 morphology grade and live-birth outcome.

Analysis of the "grade" field in the first embryo morphology data collected under the classification system developed by Society for Assisted Reproductive Technology (SART) and reported to the SART Clinic Outcomes Reporting System (SART CORS) database showed that when two embryos of the same grade were transferred on day 3, the live-birth rate declined with decreasing grade (<35 years old: good = 50.4%; fair = 42.2%; poor = 22.0%; ≥ 35 years old: good = 35.1%; fair = 23.4%; poor = 20.0%). These findings provide the first evidence that collecting the "grade" field in the national morphology collection system is valid and can be developed into a standard for use by individual SART programs for quality assurance assessment and for improved embryo selection.

Live birth from a frozen-thawed pronuclear stage embryo almost 20 years after its cryopreservation.

OBJECTIVE: To report a live birth after transfer of cryopreserved pronuclear embryos in cryostorage for almost 20 years. DESIGN: Case report. SETTING: Academic IVF center. PATIENT(S): A 42-year-old female patient with low ovarian reserve receiving donated embryos. These embryos were the result of an anonymous donation from an infertile couple who had conceived during her IVF treatment. INTERVENTION(S): Cryopreservation (slow-freeze method) and thawing of pronuclear stage embryos, and ultrasound-guided uterine ET. MAIN OUTCOME MEASURE(S): Live birth. RESULT(S): Five pronuclear embryos were thawed; two embryos survived, cleaved, and were transferred on day 2. A singleton term pregnancy was achieved with the delivery of a healthy boy. CONCLUSION(S): A healthy live birth was documented after uterine transfer of pronuclear stage cryopreserved (slow freeze)-thawed embryos that were in storage for 19 years and 7 months. To our knowledge this case represents the "oldest" cryopreserved human embryos resulting in a live birth to date.

Standardization of grading embryo morphology.

Standardization of morphologic assessment for an embryo grading system was developed and is being implemented by the Society for Assisted Reproductive Technology (SART). A recent European consensus conference of embryologists from Europe and America is working toward adopting an embryo classification system modeled similarly to that of SART that, if adopted, would produce a de facto international standard to aid cross-border collaboration.

Standardization of grading embryo morphology.

Standardization of morphological assessment for embryo grading system was developed and is being implemented by the Society for Assisted Reproductive Technology (SART). A recent European consensus conference of embryologists from Europe and America is working toward adopting an embryo classification system modeled similarly to that of SART which, if adopted, would produce a de facto international standard to aid cross border collaboration.

Does storage time influence postthaw survival and pregnancy outcome? An analysis of 11,768 cryopreserved human embryos.

OBJECTIVE: To evaluate the impact of cryopreservation storage duration on embryo survival, implantation competence, and pregnancy outcome. DESIGN: Retrospective study. SETTING: Academic tertiary-referral infertility center. PATIENT(S): In vitro fertilization patients and recipients of oocyte donation cycles who had cryopreserved embryos and underwent at least one thaw cycle from 1986 to 2007. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Postthaw survival proportion and implantation, clinical pregnancy, miscarriage, and live birth rates. RESULT(S): Length of storage time did not have a significant effect on postthaw survival for IVF or oocyte donation cycles, or for embryos frozen at the pronuclear or cleavage stages. There was no significant impact of the duration of storage on clinical pregnancy, miscarriage, implantation, or live birth rate, whether from IVF or oocyte donation cycles. Logistic regression analysis demonstrated that the length of storage time or developmental stage at freezing were not predictive of embryo survival or pregnancy outcome. Only oocyte age, survival proportion, and number of transferred embryos were positive predictors of pregnancy outcome. CONCLUSION(S): Cryostorage duration did not adversely affect postthaw survival or pregnancy outcome in IVF or oocyte donation patients.

Elective transfer of two embryos: reduction of multiple gestations while maintaining high pregnancy rates.

PURPOSE: To determine if the elective transfer of two embryos reduced the incidence of multiple gestations while maintaining high pregnancy rates. METHODS: IVF patients and recipients of oocyte donation with an elective day-3 transfer of 2 or 3 embryos were studied. RESULT(S): In IVF, the elective transfer of 2 embryos resulted in similar pregnancy rate but significantly reduced the overall incidence of multiple gestations (20% versus 39%) when compared to the elective transfer of 3 embryos. Twin gestations decreased from 28% to 19%, and triplets significantly decreased from 9% to 1%. In oocyte donation, the elective transfer of 2 embryos resulted in similar pregnancy rate but also significantly reduced the overall incidence of multiple gestations (26% versus 48%), with twins decreasing from 34% to 24%, and with a significant reduction of triplets (13% versus 2%). CONCLUSIONS: In IVF and oocyte donation, the elective transfer of 2 embryos resulted in similar pregnancy rates and significantly reduced multiple gestation rates when compared to the elective transfer of 3 embryos.

Interobserver and intraobserver variation in day 3 embryo grading.

OBJECTIVE: Variations in pregnancy rates (PR) between IVF programs are due to multiple factors, including embryo quality. Standardized embryo grading systems have been developed to improve communication between embryologists and clinicians. However, these grading systems have not been validated. We sought to quantify both interobserver and intraobserver variability using a standardized day 3 embryo grading system (Veeck scale). DESIGN: Prospective, sample-randomized, controlled, blinded study. SETTING: University hospital. PATIENT(S): Twenty-six practicing embryologists. INTERVENTION(S): Observation and grading of 35 video clips of day 3 embryos. MAIN OUTCOME MEASURE(S): Interobserver and intraobserver variability. Embryologists were also assessed by education level, years of experience, size of IVF program, and type of grading system used. Kappa scores and intraclass correlation coefficients were calculated. RESULT(S): Practicing embryologists differed from control (Lucinda Veeck) by as much as two grades, despite using the same grading system (Kappa = 0.24, interclass correlation coefficient = 0.98). There was also variability in grading the same embryo (Kappa = 0.69, interclass correlation coefficient = 0.88). Programs with higher cycle numbers per year had lower variability. CONCLUSION(S): There is substantial interobserver variability and moderate intraobserver variability among embryologists. Such variability could alter both the expected quality of embryos transferred, as well as the number transferred, both of which directly impact IVF program success.

Effect of coasting on the implantation potential of embryos transferred after cryopreservation and thawing.

OBJECTIVE: To examine the effect of withholding gonadotropins on the outcome of embryos after cryopreservation and thawing. DESIGN: Retrospective clinical evaluation of patients having cryopreserved-thawed ET trials with coasting during the corresponding ovarian stimulation cycle. SETTING: Academic tertiary clinical care unit. PATIENT(S): Patients with cryopreserved embryos having coasting in their fresh IVF cycle and age-matched controls without coasting, both groups receiving the same stimulation protocol (long GnRH agonist plus recombinant FSH). INTERVENTION(S): All patients had a cycle in which embryos were transferred fresh and a cycle of thawing of cryopreserved embryos with the aim of transferring in a steroid-supplemented cycle. MAIN OUTCOME MEASURE(S): Embryo survival, implantation, and clinical pregnancy rates. RESULT(S): Post-thawing embryo survival (66.4% vs. 73%), implantation (12.3% vs. 13.0%), and clinical pregnancy rates (31.5% vs. 38.0%) were similar in study and control groups, respectively. Patients with coasting for > or =3 days had significantly lower post-thawing embryo survival rates compared with patients having shorter duration of coasting (<3 days) and controls. Implantation and pregnancy rates, however, were similar in the three groups. CONCLUSION(S): Coasting did not seem to have a detrimental effect on oocyte and embryo quality because the implantation competence of transferred concept after cryopreservation and thawing was similar to that of controls. However, prolonged coasting (> or =3 days) had a subtle negative impact on the post-thaw survival rate.

Follicular phase serum levels of luteinizing hormone do not influence delivery rates in in vitro fertilization cycles down-regulated with a gonadotropin-releasing hormone agonist and stimulated with recombinant follicle-stimulating hormone.

OBJECTIVE: To assess the value of serum LH measurements in early and late follicular phase as predictors of ovarian response and IVF outcome in patients treated with recombinant FSH with GnRH agonist (GnRH-a) pituitary down-regulation. DESIGN: Retrospective cohort analysis. SETTING: Institutional. PATIENT(S): Women undergoing 157 consecutive IVF cycles suppressed with leuprolide acetate (LA) started in the midluteal phase and stimulated with recombinant FSH. Only women <40 years of age and with a basal cycle day 3 serum FSH

Optimizing use of assisted reproduction.

Infertile couples who have failed to achieve pregnancy now have new options that have become available in the last two decades. The costs are generally large and frequently not covered by insurance. Risks include multiple pregnancy and hyperstimulation syndrome. Evidence concerning results of several treatment options is presented. The large difference in success between age groups is displayed. Results to be expected from donor eggs to overcome the low success in older age groups (>38 years) are presented.

Impact of transabdominal ultrasound guidance on performance and outcome of transcervical uterine embryo transfer.

PURPOSE: To determine the impact of transabdominal ultrasound guidance on embryo transfer during IVF therapy. METHODS: Retrospective analysis of 823 consecutive embryo transfers. Three hundred and sixty-seven procedures performed with transabdominal ultrasound guidance were compared to 456 cases performed with the "clinical touch" method. RESULTS: Ultrasound-guided embryo transfer yielded higher, but not statistically significant, clinical pregnancy (48% vs. 44%) and implantation rates (22% vs. 20%). The incidence of multiple pregnancies, ectopic and multiple pregnancy rates were similar. The frequency of negative factors typically associated with difficult transfers, such as requirement of use of tenaculum, and presence of blood or mucus in the catheter tip, were significantly lower in the ultrasound-guided group in comparison with the clinical touch group. Ultrasound-guided embryo transfer was associated with a significantly increased easiness of transfer performance; 95% of the transfers were rated as very easy in the ultrasound-guidance group compared to 87% in the clinical touch group. The use of a soft pass catheter was the only variable independently and significantly associated with pregnancy success (odds ratio = 2.74). CONCLUSION(S): Ultrasound-guidance facilitates embryo transfer and in combination with the use of a soft catheter should be implemented to optimize embryo transfer results.

Cryopreserved embryos in the United States and their availability for research.

OBJECTIVE: To determine the number of embryos stored at assisted reproductive technology (ART) clinics in the United States and their current disposition. DESIGN: A targeted survey instrument sent by the SART-RAND team to all medical practices providing in vitro fertilization services in the United States. RESULTS: The SART-RAND team surveyed all 430 ART practices in the United States. Of these practices, 340 returned surveys for analysis. The data from these surveys were merged with data taken from the 1999 SART dataset, which contains information about practice size and success rates. Responding clinics reported a total of 396,526 embryos in storage as of April 11, 2002. The vast majority of the embryos (88.2%) were targeted for patient use. Small numbers of embryos were available for research, donation, destruction, quality assurance, or other uses. CONCLUSIONS: Nearly 400,000 embryos are stored in the United States, the majority of which (88.2%) are targeted for patient use. Few are available for research (2.8%), limiting possible conversion into embryonic stem cell lines.

Total quality improvement in the IVF laboratory: choosing indicators of quality.

The purpose of this paper is to describe a programme of total quality improvement (TQI) within the IVF laboratory and to provide specific examples of indicators that could be used in such a TQI programme. Although TQI is sometimes confused with quality control (QC) and quality assurance (QA), there are major differences between the three quality plans: (i) QC is an activity designed to ensure that a specific element within the laboratory is functioning correctly; (ii) QA is a comprehensive programme designed to looks at a laboratory as a whole and to identify problems or errors that exist in an attempt to improve the entire process; (iii) TQI is also a comprehensive monitoring process designed not only to detect and eliminate problems, but also to enhance a laboratory's performance by exploring innovation and developing flexibility and effectiveness in all processes. Indicators used in a TQI plan should be objective, relevant to the laboratory, and measure a broad range of specific events or aspects of treatment that reflect the quality of care. Threshold values for each of the indicators should be based on how the specific protocols used in the laboratory impact the outcomes and the nature of the indicators on quality of care.