Large Relative Size Research Articles

Preference for Cocaine is Represented in the Orbitofrontal Cortex by an Increased Proportion of Cocaine Use-Coding Neurons

Cocaine addiction is a harmful preference for drug use over and at the expense of other nondrug-related activities. Here we identify in the rat orbitofrontal cortex (OFC) a mechanism that explains individual preferences between cocaine use and an alternative, nondrug action. OFC neuronal activity was recorded while rats performed each of these 2 actions separately or while they chose between them. First, we found that these actions are encoded by 2 nonoverlapping neuronal populations and that the relative size of the cocaine population represented individual preferences. A larger relative size was only observed in cocaine-preferring individuals. Second, OFC neurons encoding a given individual's preferred action progressively fired more than other action-coding neurons few seconds before the preferred action was actually chosen, suggesting a prechoice neuronal competition for action selection. In cocaine-preferring rats, this manifested by a prechoice ramping-up activity in favor of the cocaine population. Finally, pharmacological manipulation of prechoice activity in favor of the cocaine population caused nondrug-preferring rats to shift their choice to cocaine. Overall, this study suggests that an individual preference for cocaine is represented in the OFC by a population size bias that systematically advantages cocaine use-coding neurons during prechoice competition for action selection.

Separation of Peptides with Forward Osmosis Biomimetic Membranes.

Forward osmosis (FO) membranes have gained interest in several disciplines for the rejection and concentration of various molecules. One application area for FO membranes that is becoming increasingly popular is the use of the membranes to concentrate or dilute high value compound solutions such as pharmaceuticals. It is crucial in such settings to control the transport over the membrane to avoid losses of valuable compounds, but little is known about the rejection and transport mechanisms of larger biomolecules with often flexible conformations. In this study, transport of two chemically similar peptides with molecular weight (Mw) of 375 and 692 Da across a thin film composite Aquaporin Inside™ Membrane (AIM) FO membrane was investigated. Despite the relative large size, both peptides were able to permeate the dense active layer of the AIM membrane and the transport mechanism was determined to be diffusion-based. Interestingly, the membrane permeability increased 3.65 times for the 692 Da peptide (1.39 × 10−12 m2·s−1) compared to the 375 Da peptide (0.38 × 10−12 m2·s−1). This increase thus occurs for an 85% increase in Mw but only for a 34% increase in peptide radius of gyration (Rg) as determined from molecular dynamics (MD) simulations. This suggests that Rg is a strong influencing factor for membrane permeability. Thus, an increased Rg reflects the larger peptide chains ability to sample a larger conformational space when interacting with the nanostructured active layer increasing the likelihood for permeation.

Traits of a lineage with extraordinary geographical range: ecology, behavior and life-history of the sailfin tetra Crenuchus spilurus

Current broad geographical distributions of species can only exist because individuals dispersed from their natal sites. The Amazon’s sailfin tetra Crenuchus spilurus has a geographical range of over 3 million km2, an area 5.7 times larger than France, which includes regions of very distinct abiotic and biotic conditions. What traits may aid in explaining such a broad geographical range, and which make the range exceptional? Here we investigate the species’ ecology and behavior using several approaches: direct field observations, ecological surveys, analyses of reproductive parameters, and diet. Broad trophic niche and frequent reproduction may help explain the wide geographical range, whereas most other traits are typical of short-ranged species: small body size, specific habitat requirements, small populations, low mobility, site-fidelity, low fecundity, and large relative size at maturation. We propose that the broad geographical range of C. spilurus is better explained by passive processes related to river dynamics. Interestingly, this species is one of few strongly dichromatic species of Amazon fish, having mutual signaling during courtship, and males exerting exclusive parental care of eggs and early larval stages. While the combination of such behavioral and ecological characteristics should promote differences among lineages and (eventually) speciation, populations far apart are remarkably morphologically similar. We suggest that ecology along with sexual selection may interplay and contribute to the inter-population morphological similarity, criterion on which Crenuchus is considered a monotypic genus.

Transfer of physical understanding in a non-tool-using parrot.

Physical cognition has generally been assessed in tool-using species that possess a relatively large brain size, such as corvids and apes. Parrots, like corvids and apes, also have large relative brain sizes, yet although parrots rarely use tools in the wild, growing evidence suggests comparable performances on physical cognition tasks. It is, however, unclear whether success on such tasks is facilitated by previous experience and training procedures. We therefore investigated physical comprehension of object relationships in two non-tool-using species of captive neotropical parrots on a new means-end paradigm, the Trap-Gaps task, using unfamiliar materials and modified training procedures that precluded procedural cues. Red-shouldered macaws (Diopsittaca nobilis) and black-headed caiques (Pionites melanocephala) were presented with an initial task that required them to discriminate between pulling food trays through gaps while attending to the respective width of the gaps and size of the trays. Subjects were then presented with a novel, but functionally equivalent, transfer task. Six of eight birds solved the initial task through trial-and-error learning. Four of these six birds solved the transfer task, with one caique demonstrating spontaneous comprehension. These findings suggest that non-tool-using parrots may possess capacities for sophisticated physical cognition by generalising previously learned rules across novel problems.

Effect of grain size on the superelastic response of a FeMnAlNi polycrystalline shape memory alloy

The effect of heat treatments on superelasticity was investigated in a FeMnAlNi polycrystalline alloy using incremental tensile strain tests at room temperature. Large grains of more than several millimeters can be obtained by a cyclic heat treatment process and the average grain size can be controlled by the number of heat treatment cycles. Improved superelastic response is observed in samples with large relative grain sizes, exhibiting increased elongation to fracture, lower critical stress for transformation, and higher reversibility.

Features of successful academic hospitalist programs: Insights from the SCHOLAR (SuCcessful HOspitaLists in academics and research) project.

As clinical demands increase, understanding the features that allow academic hospital medicine programs (AHPs) to thrive has become increasingly important. To develop and validate a quantifiable definition of academic success for AHPs. A working group of academic hospitalists was formed. The group identified grant funding, academic promotion, and scholarship as key domains reflective of success, and specific metrics and approaches to assess these domains were developed. Self-reported data on funding and promotion were available from a preexisting survey of AHP leaders, including total funding/group, funding/full-time equivalent (FTE), and number of faculty at each academic rank. Scholarship was defined in terms of research abstracts presented over a 2-year period. Lists of top performers in each of the 3 domains were constructed. Programs appearing on at least 1 list (the SCHOLAR cohort [SuCcessful HOspitaLists in Academics and Research]) were examined. We compared grant funding and proportion of promoted faculty within the SCHOLAR cohort to a sample of other AHPs identified in the preexisting survey. Seventeen SCHOLAR programs were identified, with a mean age of 13.2 years (range, 6-18 years) and mean size of 36 faculty (range, 18-95). The mean total grant funding/program was $4 million (range, $0-$15 million), with mean funding/FTE of $364,000 (range, $0-$1.4 million); both were significantly higher than the comparison sample. The majority of SCHOLAR faculty (82%) were junior, a lower percentage than the comparison sample. The mean number of research abstracts presented over 2 years was 10.8 (range, 9-23). Our approach effectively identified a subset of successful AHPs. Despite the relative maturity and large size of the programs in the SCHOLAR cohort, they were comprised of relatively few senior faculty members and varied widely in the quantity of funded research and scholarship. Journal of Hospital Medicine 2016;11:708-713. © 2016 Society of Hospital Medicine.

Megalictis, the Bone-Crushing Giant Mustelid (Carnivora, Mustelidae, Oligobuninae) from the Early Miocene of North America.

We describe cranial and mandibular remains of three undescribed individuals of the giant mustelid Megalictis ferox Matthew, 1907 from the latest Arikareean (Ar4), Early Miocene mammal fauna of Nebraska, and Wyoming (USA) housed at the American Museum of Natural History (New York, USA). Our phylogenetic hypothesis indicates that Ar4 specimens assigned to M. ferox constitute a monophyletic group. We assign three additional species previously referred to Paroligobunis to Megalictis: M. simplicidens, M. frazieri, and “M.” petersoni. The node containing these four species of Megalictis and Oligobunis forms the Oligobuninae. We test the hypothesis that Oligobuninae (Megalictis and Oligobunis) is a stem mustelid taxon. Our results indicate that the Oligobuninae form the sister clade to the crown extant mustelids. Based on the cranium, M. ferox is a jaguar-size mustelid and the largest terrestrial mustelid known to have existed. This new material also sheds light on a new ecomorphological interpretation of M. ferox as a bone-crushing durophage (similar to hyenas), rather than a cat-like hypercarnivore, as had been previously described. The relative large size of M. ferox, together with a stout rostrum and mandible made it one of the more powerful predators of the Early Miocene of the Great Plains of North America.

A length-based approach to predator–prey relationships in marine predators

Body size is a critical feature of the ecology of most organisms and has been used to describe and understand predator–prey interactions in both terrestrial and aquatic environments. Most previous studies have used prey mass to examine the relationships between predator size and prey size; however, using prey lengths may provide a different perspective, particularly for gape-limited fishes. Using a large database of predator and prey lengths for marine aquatic predators, I found the expected positive wedge-shaped relationship between predator length and prey length and a negative converging relationship between relative prey length (prey–predator length ratio = a measure of trophic niche breadth) and predator length. Distinct patterns in the size scaling of this measure of trophic niche breadth were identified using quantile regression: converging relationships were common among adults but absent among larvae. This difference suggests contrasting ontogenetic foraging opportunities between adults and larvae: a lack of large relative prey sizes for the largest adult predators, and a greater ability of larvae to include larger prey items in their diet as they grow.

Physico-chemical and Magnetic Properties of Co-Zr Doped Ba-hexaferrites Using Self Combustion and Urea Assisted Method – A Comparative Study

The physico-chemical properties of Ba-hexaferrite with change in dopants concentration (Co and Zr) have been investigated. BaCoxZrxFe12-2xO19 nanoparticles synthesized by using self combustion (series 1) as well as urea assisted citrate precursor (series 2) routes were analyzed by using various spectroscopic techniques. XRD study reveals well crystalline, monophasic, nanoparticles (39nm) at rather low temperature in series 2 as compared to series 1 with relative impurity phase and large crystallite size (86nm). Room temperature magnetic study shows that the method of preparation effects structural as well as magnetic parameters.

Francis x. connor. Literary Folios and Ideas of the Book in Early Modern England.

Only in a very Shakespeare-centric view of book history could Mr. William Shakespeares Comedies, Histories, & Tragedies (1623) usurp the title ‘First Folio’. Francis X. Connor’s book discusses and tabulates a sweep of literary folios from John Harington’s translation of Ariosto in 1591 to Thomas Bayley’s Herba Pareitic of 1650, arguing that these books establish a sense of literary prestige during an intense period of canon-formation. Connor demonstrates that the folio format is the bibliographic triumph over the old idea of the ‘stigma of print’, and argues that by publishing these big books (folio does not denote standard dimensions in the period, but is a term popularly used to signal relative large size), authors and stationers attempted to reconcile literary quality, monumentality, and the demands of the marketplace. The History of Text Technologies series takes its intellectual coordinates from the new histories of the book inaugurated by D.F. McKenzie, Robert Darnton and Roger Chartier. One notable strength of Connor’s analysis is his combination of bibliographic and readerly approaches. Comparing folio publications of the works of Sidney and Daniel, which enable readers to participate in their evocation of literary culture, with the closed form of Jonson’s 1616 Workes, places potential readers’ interactions with these books at the centre of their effect. These readers are, however, hypothetical: conjured into being by the paratexual apparatus of the texts. It would be fascinating to trace—as Heidi Brayman Hackel has for the Arcadia—the ways in which actual readers left marks of these encounters on, say, those temptingly wide margins of Jonson’s single-column centred pages. Connor’s scholarship is also lucidly sensitive to metaphors for the book, particularly in his account of the ways Daniel’s use of architectural imagery establishes his folio as both collaborative and functional. Daniel’s ready acceptance of the necessity of printing errors—‘who so looks/ T’have all things in perfection … never must read books’—gives readers a participatory role: by correcting mistakes, they enter into the mechanic and intellectual labours of book production.

Association of HTR2A Polymorphisms with Risperidone Efficacy in Chinese Han Schizophrenia Patients

ABS TRACT: Association of HTR2A polymorphisms with risperidone efficacy in Chinese Han schizophrenia patients Objectives: The 5-HT2A receptor is one of the most important serotonin receptors, serving as a major target for risperidone. Rs6311 and rs6313 polymorphisms in the HTR2A gene have been reported to be associated with response to risperidone treatment; however, many previous studies have yielded conflicting results. To confirm the importance of these polymorphisms in risperidone treatment and provide more evidence for the routine use of these pharmacogenetic biomarkers in clinical practice, we carried out an association analysis of rs6311 and rs6313 polymorphisms with risperidone efficacy in Chinese Han patients with schizophrenia. Methods: Two independent cohorts of unrelated subjects were recruited from Henan and Shanghai (95 and 113 subjects, respectively). After 4- or 8-week risperidone monotherapy, the rs6311 and rs6313 polymorphisms of these subjects were genotyped with direct DNA sequencing. Clinical improvement was measured by the reduction of the PANSS scores (including the total and subscale scores). UNIANOVA and case-control study was used to evaluate the effects of rs6311 and rs6313 polymorphisms on the therapeutic efficacy of risperidone. Results: As in previous studies, the rs6311G allele was found in complete linkage disequilibrium with the rs6313C allele. However, neither the rs6311 nor the rs6313 polymorphism significantly influenced clinical improvement during risperidone treatment. Neither the allele nor the genotype frequencies were significantly different between responder and non-responder subgroups. Conclusions: No significant association between HTR2A polymorphisms (rs6313 and rs6311) and risperidone efficacy was found in the present study. The relative large sample size and two independent cohorts of subjects in the present study enhance the reliability of our findings.

Arctic skate Amblyraja hyperborea preys on remarkably large glacial eelpouts Lycodes frigidus.

During scientific surveys on the continental slopes north-west of Spitsbergen and off north-east Greenland (c. 600 and 1000 m depths), two female Arctic skates Amblyraja hyperborea were caught while swallowing extraordinary large individuals of glacial eelpout Lycodes frigidus. The total length (LT) of the prey constituted 50 and 80% of the LT of the skates, which reveal that A. hyperborea are capable predators of fishes of surprisingly large relative size.

3D visualization of TiO2 nanocrystals in mesoporous nanocomposite using energy filtered transmission electron microscopy tomography.

IntroductionMesoporous silica, SBA-15, is one of the best candidate for the supporting material of catalytic nanoparticles because of its relative large and controllable pore size and large specific surface area [1]. So far, various nanoparticles, such as Au, Pt and Pd, have been introduced into the pore for catalytic application [2]. The size of nanoparticles supported inside SBA-15 is restricted by that of the pore, and they are usually ranging from 2 nm and 50 nm in space.It is necessary to anchor the nanoparticles within pores to avoid segregation / sintering of them. However, it is difficult to anchor them within pores in the case of use of deposition-precipitation method due to extreme low iso-electric point (IEP) of silica (∼2). Therefore, TiO2 nanocrystals (IEP 6-8) were then introduced to anchor AuNPs [3].In this study, EFTEM tomography was applied to examine the effectiveness of TiO2 for AuNPs. Materials and methodAu/TiO2-SBA-15 was embedded into epoxy resin for electron microscopy and microtomed to about 30 nm thickness. EFTEM-tomography was operated at 120 kV and using Ti-L ionization edge via three-window method. Prior to EFTEM, STEM-HAADF tomography was also carried out for visualizing AuNPs and for comparison. Result and discussionFigure1 shows 3D-volume of AuNPs and TiO2 nanocrystals from EFTEM-tomography. TiO2 nanocrystals in the porous material were successfully visualized using EFTEM -tomography, and local relationship between AuNPs and TiO2 nanocrystals were revealed. A large number of TiO2 nanocrystals were randomly distributed in the SBA-15. It was found that most AuNPs were directly on the exposed TiO2 nanocrystals. It implies that TiO2 nanocrystals were exposed on the surface of the pore and anchored AuNPs inside the pores.jmicro;63/suppl_1/i27/DFU081F1F1DFU081F1Fig. 1.3D volume of AuNPs and TiO2 nanocrystals.

Imaging intracranial vessel wall pathology with magnetic resonance imaging: current prospects and future directions.

To date, the probable cause of ischemic stroke is often inferred from the size and location of the infarct, in combination with an evaluation of the heart and the presence of extracranial arterial occlusion or high-grade stenosis.1 Currently used conventional lumenography-based methods such as digital subtraction angiography, computed tomography angiography, and magnetic resonance (MR) angiography are used to determine the presence of such an acute occlusion or high-grade arterial stenosis. From extracranial studies, it is known that luminal narrowing may be absent in patients with severe atherosclerosis owing to arterial remodeling.2–4 Therefore, these methods do not provide information about the underlying pathological processes, which most often involve the vessel wall.5 Vessel wall changes such as vessel wall thickening, enhancement, or the presence of vulnerable atherosclerotic plaques without luminal stenosis are therefore often missed but might be of importance for a better understanding of ischemic stroke.6 Furthermore, intracranial atherosclerosis is an important cause of ischemic stroke7 and often involves the vessel wall. Patients with intracranial atherosclerosis have high recurrent stroke rates,8 and increasingly more attention is being directed to the assessment of the intracranial vessel wall, necessitating an imaging technique directly assessing the intracranial vessel wall. MR imaging (MRI) seems the most promising technique to reliably image intracranial vessel wall pathologies because of its superior soft tissue contrast. Recent advances in MRI9 have made it possible to obtain information about these abnormalities within the intracranial vessel wall, which provides an imaging tool to investigate the role of intracranial vessel wall abnormalities in the diagnosis of stroke. In this review, we discuss the current status of intracranial vessel wall MRI and its potential to identify different intracranial vessel wall pathologies. First, we present the state-of-the-art MRI methods to visualize the intracranial vessel wall …

Nanofiltration hollow fiber membranes with high charge density prepared by simultaneous electron beam radiation-induced graft polymerization for removal of Cr(VI)

A novel kind of nanofiltration (NF) hollow fiber membranes with high density of negative charges and relative high permeate flux was prepared by grafting of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) onto a polysulfone (PSf) ultrafiltration hollow fiber membrane using the simultaneous electron beam radiation-induced method. ATR-FTIR and FESEM analyses revealed that the monomer was grafted on both the outer and inner surfaces of the membrane. The effects of irradiation dose and monomer concentration on the mean pore size and performance of the membranes were investigated. The prepared NF membranes were used for removal of Cr(VI) from aqueous solution under varying conditions such as pH value, initial Cr(VI) concentration and coexisting ions. The experimental results showed that Cr(VI) could be effectively removed by the resulting NF membranes when the pH of the solution was higher than 8 and the performance of Cr(VI) removal was nearly not affected by the presence of Na2SO4 and NaCl in the experimental range. It was indicated that the high negative charge density resulting from the high degree of grafting made the grafted membranes achieve nanofiltration performance at a relative large pore size.

Quantitative biokinetics and systemic translocation of various gold nanostructures are highly dependent on their size and shape.

Gold nanostructures with promising applications in biomedical field have attracted great attention. However, some fundamental questions other than the development of novel applications should be elucidated before they can actually serve as biomedicines in the clinic. Bio-safety is one of the most important issues. Since numerous modifications (e.g., surface coating and composites) have been designed on gold nanoparticles (GNPs) to extend their application, there would be hundreds of GNPs synthesized in the lab although the prototypes of GNPs (i.e., cluster, shell, rod, sphere, cage, and star) are rather limited. Thus, in the present work we aim to conduct our experiments only on the most basic types of GNPs--including gold nanocluster (GNC), gold nanorod (GNR) and gold nanosphere (GNS), to investigate their biodistribution and toxicities in vivo, in the hope of revealing some basic rules which could be further extended to other complicated situations. Bovine serum albumin (BSA) was coated at the surface to increase their plasma stability and of the same BSA coating would help to compare the fate and behaviors of various GNPs in vivo. After intravenous administration of different GNPs with an equal content of gold element at 0.5 mg/kg in mice, samples were harvested at a series of time points. Biodistribution was compared among different GNPs and the process of accumulation-retention-clearance of each kind of GNP was also observed through quantification analysis by inductively coupled plasma-mass spectrometry (ICP-MS). The results showed, with the same BSA coating at the surface and similar negative charge, size rather than shape was dominating the in vivo fate of GNPs. Even between GNC and hydrolyzed GNC with their size at 7.1 and 3.2 nm, huge difference in the kidney accumulation was observed. Totally, GNR and GNS in relative large size preferred to accumulate in liver and spleen whereas GNC in relative small size tended to accumulate in liver and kidney. GNPs resided in liver were hardly cleared out of body till 28 d whereas their accumulation in kidney was almost entirely eliminated with prolonged time, although not as rapid as reported in previous work. In vivo toxicities evaluated by pathology observation and blood biochemical analysis also revealed slight liver and kidney damage, basically associated with the biodistribution pattern of GNPs.

SU‐E‐I‐68: Practical Considerations On Implementation of the Image Gently Pediatric CT Protocols

Purpose:One limitation associated with the Image Gently pediatric CT protocols is practical implementation of the recommended manual techniques. Inconsistency as a result of different practice is a possibility among technologist. An additional concern is the added risk of data error that would result in over or underexposure. The Automatic Exposure Control (AEC) features automatically reduce radiation for children. However, they do not work efficiently for the patients of very small size and relative large size. This study aims to implement the Image Gently pediatric CT protocols in the practical setting while maintaining the use of AEC features for pediatric patients of varying size.Methods:Anthropomorphological abdomen phantoms were scanned in a CT scanner using the Image Gently pediatric protocols, the AEC technique with a fixed adult baseline, and automatic protocols with various baselines. The baselines were adjusted corresponding to patient age, weight and posterioranterior thickness to match the Image Gently pediatric CT manual techniques. CTDIvol was recorded for each examination. Image noise was measured and recorded for image quality comparison. Clinical images were evaluated by pediatric radiologists.Results:By adjusting vendor default baselines used in the automatic techniques, radiation dose and image quality can match those of the Image Gently manual techniques. In practice, this can be achieved by dividing pediatric patients into three major groups for technologist reference: infant, small child, and large child. Further division can be done but will increase the number of CT protocols. For each group, AEC can efficiently adjust acquisition techniques for children. This implementation significantly overcomes the limitation of the Image Gently manual techniques.Conclusion:Considering the effectiveness in clinical practice, Image Gently Pediatric CT protocols can be implemented in accordance with AEC techniques, with adjusted baselines, to achieve the goal of providing the most appropriate radiation dose for pediatric patients of varying sizes.

Shape-Selective Formation of Monodisperse Copper Nanospheres and Nanocubes via Disproportionation Reaction Route and Their Optical Properties

Synthesis of stable and monodisperse Cu nanocrystals of controlled morphology has been a long-standing challenge. In this Article, we report a facile disproportionation reaction approach for the synthesis of such nanocrystals in organic solvents. Either spherical or cubic shapes can be produced, depending on conditions. The typical Cu nanospheres are single crystals with a size of 23.4 ± 1.5 nm, and can self-assemble into three-dimensional (3D) nanocrystal superlattices with a large scale. By manipulating the chemical additives, monodisperse Cu nanocubes with tailorable sizes have also been obtained. The probable formation mechanism of these Cu nanocrystals is discussed. The narrow size distribution results in strong surface plasmon resonance (SPR) peaks even though the resonance is located in the interband transition region. Double SPR peaks are observed in the extinction spectra for the Cu nanocubes with relative large sizes. Theoretical simulation of the extinction spectra indicates that the SPR band l...

Cost-Effectiveness of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease

Letters21 January 2014Cost-Effectiveness of Tolvaptan in Autosomal Dominant Polycystic Kidney DiseaseKevin F. Erickson, MD, MS, Glenn M. Chertow, MD, MPH, and Jeremy D. Goldhaber-Fiebert, PhDKevin F. Erickson, MD, MSFrom Stanford University, Stanford, California.Search for more papers by this author, Glenn M. Chertow, MD, MPHFrom Stanford University, Stanford, California.Search for more papers by this author, and Jeremy D. Goldhaber-Fiebert, PhDFrom Stanford University, Stanford, California.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/L14-5001-7 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail IN RESPONSE:We agree with Drs. Lineen and Naimark that the eGFR is an imperfect surrogate for the actual GFR and that decreases in the GFR are not identical to those in the eGFR. The treatment benefit that the TEMPO trial investigators describe may also seem greater when assessed using the eGFR instead of the true GFR, although measuring the latter would have been challenging given the relative large sample size and dispersed geography described in this trial.The eGFR necessarily introduces regression error. Ideally, we could relate our model inputs (for example, mortality rates, health-related quality of life, and ...Reference1. Campbell EG, Pham-Kanter G, Vogeli C, Iezzoni LI. Physician acquiescence to patient demands for brand-name drugs: results of a national survey of physicians [Letter]. JAMA Intern Med. 2013;173:237-9. [PMID: 23303297] CrossrefMedlineGoogle Scholar Author, Article, and Disclosure InformationAffiliations: From Stanford University, Stanford, California.Disclosures: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M13-0381. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetailsSee AlsoCost-Effectiveness of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease Kevin F. Erickson , Glenn M. Chertow , and Jeremy D. Goldhaber-Fiebert Cost-Effectiveness of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease James Lineen , David M.J. Naimark , and Cost-Effectiveness of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease Christopher M. Blanchette , Benjamin Gutierrez , and Keith Friend Cost-Effectiveness of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease James Lineen , David M.J. Naimark , and Cost-Effectiveness of Tolvaptan in Autosomal Dominant Polycystic Kidney Disease Christopher M. Blanchette , Benjamin Gutierrez , and Keith Friend Metrics 21 January 2014Volume 160, Issue 2Page: 143KeywordsHyponatremiaKidneysLongitudinal studiesPolycystic kidney diseaseQuality of lifeRenal analysisRenal failureStatins ePublished: 21 January 2014 Issue Published: 21 January 2014 CopyrightCopyright © 2014 by American College of Physicians. All Rights Reserved.PDF DownloadLoading ...

52 VITRIFICATION OF DAY-8 EQUINE EXPANDED BLASTOCYST: AN IN VITRO COMPARISON OF DIRECT VERSUS INDIRECT MECHANICAL INTRODUCTION OF CRYOPROTECTANT

The cryopreservation of equine expanded blastocysts (>300 μm) has been largely unsuccessful primarily due to the low permeability of the embryo to cryoprotectants. This low permeability has been attributed to the acellular glycoprotein capsule that develops when an embryo approaches approximately 300 μm in diameter. Mechanical alternatives may provide a means to overcome the capsule barrier and the relative large embryo size to successfully cryopreserve equine embryos. The objective of this experiment was to compare re-expansion rates of vitrified equine expanded blastocysts following either direct or indirect mechanical introduction of cryoprotectants using a coaxial microinjection system (Dracula pipette). Twenty-six Day-8 expanded blastocysts were subjected to capsule puncture, cryoprotectant injection, and blastocoele fluid extraction (direct treatment) or capsule puncture and blastocoele fluid extraction (indirect treatment) before cryopreservation. The Dracula pipette incorporates the injection pipette within the holding pipette, facilitating aspiration of blastocoele fluid or injection of cryoprotectant in a single unit. A standard vitrification protocol using a final concentration of 3.4 M glycerol and 4.6 M ethylene glycol at cryopreservation was used. Vitrified embryo re-expansion was assessed following in vitro culture at 24, 48, and 72 h post-warming. Differences across treatments were analysed using the Student's t-test for re-expansion and the chi-squared test of independence for capsule loss. Pre-vitrification embryo mean diameter (mean ± standard error) for direct and indirect treatment groups were not different, 979 ± 85.6 μm and 912 ± 101.4 μm, respectively (P = 0.62). Post-vitrification embryo mean diameters were not different for the direct and indirect treatments (688 ± 63 and 662 ± 75 μm, respectively; P = 0.79). Following 72 h of in vitro culture, there was no difference in mean embryo diameter (1813.16 ± 209 μm v. 1383.88 ± 198 μm; P = 0.21), or re-expansion rates (69 v. 69%) for direct and indirect treatment groups, respectively. However, partial or total capsule loss was 69% (9/13) for direct treatment embryos compared with 30% (4/13) for indirect treatment embryos (P = 0.049). Results from this experiment demonstrate that capsule puncture and blastocoele fluid extraction before vitrification resulted in high re-expansion rates of Day-8 equine expanded blastocysts after warming. More importantly, the relatively large percentage of capsule failure when directly introducing cryoprotectant into the embryo may interfere with maternal recognition of pregnancy following embryo transfer. Nonetheless, based on the embryonic re-expansion rate of vitrified equine embryos following the indirect technique, we anticipate that a relatively high pregnancy rate can be obtained if this technique is used.