bluuebunny/crossref_metadata_2025 huggingface dataset:
Emerging Roles for MicroRNAs in Perioperative Medicine
Authors: Neudecker Viola , Brodsky Kelley S. , Kreth Simone , Ginde Adit A. , Eltzschig Holger K.
Published: December 2015

AbstractAbstract

MicroRNAs (miRNAs) are small, non–protein-coding, single-stranded RNAs. They function as posttranscriptional regulators of gene expression by interacting with target mRNAs. This process prevents translation of target mRNAs into a functional protein. miRNAs are considered to be functionally involved in virtually all physiologic processes, including differentiation and proliferation, metabolism, hemostasis, apoptosis, and inflammation. Many of these functions have important implications for anesthesiology and critical care medicine. Studies indicate that miRNA expression levels can be used to predict the risk for eminent organ injury or sepsis. Pharmacologic approaches targeting miRNAs for the treatment of human diseases are currently being tested in clinical trials. The present review highlights the important biological functions of miRNAs and their usefulness as perioperative biomarkers and discusses the pharmacologic approaches that modulate miRNA functions for disease treatment. In addition, the authors discuss the pharmacologic interactions of miRNAs with currently used anesthetics and their potential to impact anesthetic toxicity and side effects.

MicroRNAs are small, noncoding RNA molecules that have the capability to regulate protein expression at the posttranslational level. They play important roles as modulators of various biological functions including health and disease. This review provides an overview of microRNA biology, and specifically highlights their functional roles for the field of perioperative medicine.
An Independent Inter- and Intraobserver Agreement Evaluation of the AOSpine Subaxial Cervical Spine Injury Classification System
Authors: Urrutia Julio , Zamora Tomas , Yurac Ratko , Campos Mauricio , Palma Joaquin , Mobarec Sebastian , Prada Carlos
Published: December 2015

Study Design.

An agreement study.

Objective.

The aim of this study was to perform an independent interobserver and intraobserver agreement assessment of the AOSpine subaxial cervical spine injury classification system.

Summary of Background Data.

The AOSpine subaxial cervical spine injury classification system was recently described. It showed substantial inter- and intraobserver agreement in the study describing it; however, an independent evaluation has not been performed.

Methods.

Anteroposterior and lateral radiographs, computed tomography scans, and magnetic resonance imaging of 65 patients with acute traumatic subaxial cervical spine injuries were selected and classified using the morphologic grading of the subaxial cervical spine injury classification system by 6 evaluators (3 spine surgeons and 3 orthopedic surgery residents). After a 6-week interval, the 65 cases were presented to the same evaluators in a random sequence for repeat evaluation. The kappa coefficient (κ) was used to determine the inter- and intraobserver agreement.

Results.

The interobserver agreement was substantial when considering the fracture main types (A, B, C, or F), with κ = 0.61 (0.57–0.64), but moderate when considering the subtypes: κ = 0.57 (0.54–0.60). The intraobserver agreement was substantial considering the fracture types, with κ = 0.68 (0.62–0.74) and considering subtypes, κ = 0.62 (0.57–0.66). No significant differences were observed between spine surgeons and orthopedic residents in the overall inter- and intraobserver agreement, or in the inter- and intraobserver agreement of specific A, B, C, or F type of injuries.

Conclusion.

This classification allows adequate agreement among different observers and by the same observer on separate occasions. Future prospective studies should determine whether this classification allows surgeons to decide the best treatment for patients with subaxial cervical spine injuries.

Level of Evidence: 3
Human papillomavirus infection by anatomical site among Greek men and women: a systematic review
Authors: Tsikis Savas , Hoefer Lea , Charnot-Katsikas Angella , Schneider John A.
Published: December 2015

We systematically reviewed the literature on anal, penile, cervical, and oropharyngeal human papillomavirus (HPV) infection in Greece to provide a comprehensive overview of HPV prevalence and to explore the reporting of HPV in Greek men and women. A total of five databases, including PubMed and Scopus, were searched up until 1 January 2015 for studies looking at HPV prevalence, incidence, or risk factors by anatomical site. We identified 50 eligible studies for inclusion. The majority of them were cervical studies (n=26) followed by head and neck studies (n=13) with only two studies exclusively focusing on anal sites and two on penile sites. The remaining studies examined prevalence from multiple sites. Most studies looked at small, high-risk populations, and HPV prevalence ranged from 2.5–43.4% for cervical studies; 0–91% for head and neck studies; 54.6–78.4% for anal studies; and 20.3–66.7% for penile studies. Age, smoking, and number of sexual partners were the commonly assessed risk factors. There were significant sex and anatomic site disparities in the reporting of HPV prevalence. Given the relationship between HPV infection and the increasing incidence of anal cancer in men, more research is needed to reveal the prevalence of HPV at these sites in Greek men, especially given the reports of the declining health of the Greek population.
ELEVATED INTRAOCULAR PRESSURE FOLLOWING PARS PLANA VITRECTOMY DUE TO TRAPPED GAS IN THE POSTERIOR CHAMBER
Authors: Chin Eric K. , Almeida David R. P. , Strohbehn Austin L. , Mahajan Vinit B. , Russell Stephen R. , Folk James C.
Published: December 2015

Purpose:

Elevated intraocular pressure is relatively common following pars plana vitrectomy and intraocular gas tamponade. We discuss a series of patients who experienced elevated intraocular pressure from pupillary block and angle closure secondary to trapped gas in the posterior chamber.

Methods:

Case series.

Results:

Case 1 is a patient who underwent pars plana vitrectomy for retinal detachment repair. The intraocular pressure was elevated on postoperative Day 3 because of trapped gas in the posterior chamber, and it did not lower with prone positioning, maximal medical therapy, and laser peripheral iridotomies. Aspiration of the trapped gas was done with the patient sitting upright using a 27-gauge needle at the limbus, which was curative. Case 2 provides anterior-segment optical coherence tomography images that confirmed the location of the trapped gas resulting in angle closure. Case 3 demonstrates the unfortunate sequelae of a central retinal artery occlusion following delayed recognition of this entity. Case 4 highlights the challenges encountered when migratory gas is also seen elsewhere in the eye.

Conclusion:

Clinicians should be aware of elevated intraocular pressure secondary to trapped gas in the posterior chamber, which may be recalcitrant to medical therapy. Aspiration of the trapped gas can alleviate both pupillary block and angle closure without compromising the gas tamponade.
Multifocal Intraocular Lens Results in Correcting Presbyopia in Eyes After Radial Keratotomy
Authors: Kim Kyeong Hwan , Seok Kyung-won , Kim Wan Soo
Published: December 2015

Objectives:

To report results of multifocal intraocular lens (IOL) implantation in 2 patients with refractive error and presbyopia after previous radial keratotomy (RK).

Methods:

A refractive multifocal IOL with rotational asymmetry (LS313-MF30; Oculentis, Berlin, Germany) was implanted.

Results:

The first patient was a 60-year-old man with myopia who underwent unilateral RK 20 years before. His uncorrected distance visual acuity (UDVA) was 20/400, and his distance corrected near vision was J9 in both eyes. Six months after bilateral surgery, his binocular UDVA and uncorrected near visual acuity (UNVA) improved to 20/20 and J1, respectively, although he experienced diurnal fluctuation. The second patient was a 55-year-old woman with hyperopia who underwent bilateral RK 18 years before. Uncorrected distance visual acuity was 20/25 in both eyes, but UNVA was between J9 and J10. Three months after unilateral surgery, UDVA and UNVA of the postsurgical eye improved to 20/20 and J1, respectively. Neither patient reported any significant photic phenomena, and both were satisfied with the results of treatment.

Conclusions:

The desirable clinical outcomes and levels of satisfaction expressed by these patients indicate that surgery using this particular multifocal IOL may benefit presbyopic patients with previous RK.
Intraocular Pressure After 2 Hours of Small-Diameter Scleral Lens Wear
Authors: Nau Cherie B. , Schornack Muriel M. , McLaren Jay W. , Sit Arthur J.
Published: December 2015

Objectives:

Compression of episcleral veins or deformation of tissue in the Schlemm's canal beneath the landing zone of scleral lenses could elevate intraocular pressure (IOP). We examined the effect of 2 hr of small-diameter scleral lens wear on IOP.

Methods:

Twenty-nine participants, 29 ± 6 years old (mean ± SD) who experienced no history of eye disease or scleral lens wear, were included in the study. Each participant was fitted with a 15-mm Jupiter scleral lens on one eye (study eye). Intraocular pressure was measured in both eyes by pneumatonometry centrally on the cornea and peripherally on the sclera. The lens was then placed on one eye and was worn for 2 hr. Intraocular pressure was remeasured immediately after lens placement, at 1 and 2 hr of lens wear, and immediately after lens removal. Intraocular pressure after removal of the scleral lens was compared with IOP before placing the lens and to IOP in the control eye using paired t tests.

Results:

Immediately after removing the scleral lens, mean central IOP in the study eye (13.9 ± 3.1 mm Hg) was not different from mean central IOP in the control eye (13.5 ± 2.2 mm Hg, P = 0.4) or in the same eye before lens wear (13.6 ± 1.9 mm Hg, P = 0.6). There were also no differences in IOP measured peripherally at 2 hr of lens wear (P = 0.8).

Conclusions:

Neophyte scleral lens wear of a 15-mm scleral lens for 2 hr does not increase IOP in healthy eyes.
The role of emergency physicians in the institutionalization of emergency medicine
Authors: van Schothorst Jannine , van den Brand Crispijn L. , Gaakeer Menno I. , Wallenburg Iris
Published: December 2015

Objectives

Emergency medicine is a fast-growing medical profession. Nevertheless, the clinical activities emergency physicians (EPs) carry out and the responsibilities they have differ considerably between hospitals. This article addresses the question how the role of EPs is shaped and institutionalized in the everyday context of acute care in hospitals.

Methods

A cross-case ethnographic study was conducted, comprising observations, document analysis, and in-depth interviews in three emergency departments in the Netherlands.

Results

Drawing on the theoretical concept of institutional work, we show that managers, already established medical specialties, and EPs all conduct institutional work to enhance private interests, which both restricts and enlarges EPs’ work domain. These actions are strategic and intentional, as well as unintentional and part of EPs’ everyday work in acute care delivery. It is in this very process that tasks and responsibilities are redistributed and the role of the EP is shaped.

Discussion

In contemporary literature it is often argued that the role and status of EPs should be enhanced by strengthening regulation and improving training programs. This article shows that attention should also be paid to the more subtle everyday processes of role development.
Telemetry-assisted early detection of STEMI in patients with atypical symptoms by paramedic-performed 12-lead ECG with subsequent cardiological analysis
Authors: Campo Dell’ Orto Marco , Hamm Christian , Liebetrau Christoph , Hempel Dorothea , Merbs Reinhold , Cuca Colleen , Breitkreutz Raoul
Published: December 2015

Objectives

ECG is an essential diagnostic tool in patients with acute coronary syndrome. We aimed to determine how many patients presenting with atypical symptoms for an acute myocardial infarction show ST-segment elevations on prehospital ECG. We also aimed to study the feasibility of telemetric-assisted prehospital ECG analysis.

Patients and methods

Between April 2010 and February 2011, consecutive emergency patients presenting with atypical symptoms such as nausea, vomiting, atypical chest pain, palpitations, hypertension, syncope, or dizziness were included in the study. After basic measures were completed, a 12-lead ECG was written and telemetrically transmitted to the cardiac center, where it was analyzed by attending physicians. Any identification of an ST-elevation myocardial infarction resulted in patient admission at the closest coronary angiography facility.

Results

A total of 313 emergency patients presented with the following symptoms: dyspnea, nausea, vomiting, dizziness/collapse, or acute hypertension. Thirty-four (11%) patients of this cohort were found to show ST-segment elevations on the 12-lead ECG. These patients were directly admitted to the closest coronary catheterization facility rather than the closest hospital. The time required for transmission and analysis of the ECG was 3.6±1.2 min.

Conclusion

Telemetry-assisted 12-lead ECG analysis in a prehospital setting may lead to earlier detection of ST-elevation myocardial infarction in patients with atypical symptoms. Thus, a 12-lead ECG should be considered in all prehospital patients both with typical and atypical symptoms.
Cow's Milk Allergy Prescribing Is Influenced by Regional and National Guidance
Authors: Wauters Lucas , Brown Trevor , Venter Carina , Dziubak Robert , Meyer Rosan , Brogan Breege , Walsh Joanne , Fox Adam T. , Shah Neil
Published: December 2015

Objectives:

Cow's milk allergy (CMA) is the most common food allergy in children with many clinical manifestations, leading to misdiagnoses such as gastro‐oesophageal reflux, infantile colic, and lactose intolerance with inappropriate prescribing. We aimed to determine the impact of infant feeding guidelines on CMA prescribing in UK primary care using a simple and inexpensive training package.

Methods:

Prospectively collected data of infant feeding prescriptions in Northern Ireland from June 2012 to March 2014 were analysed with the intervention period between November 2012 and March 2013. A comparison was made between hypoallergenic formulae, appropriate for CMA, versus alternative prescriptions including antiregurgitation and colic products, lactose‐free and partially hydrolysed milks, or infant Gaviscon.

Results:

Comparing pre‐ and postintervention period, the total quantity of hypoallergenic formulae increased by 63.2% and alternative prescriptions decreased by 44.6% (P < 0.001). The total amount of all prescribed products decreased by 41.0% (P < 0.001). During the study period, the proportion of recommended CMA treatment increased from 3.4% before training to 9.8% in the short‐ and long‐term follow‐up (P < 0.001). The overall increase was £33,508 per year or £95.5 per general practitioner's surgery.

Conclusions:

We present the first study evaluating the impact of infant feeding guidelines on CMA prescribing in UK primary care. Practical advice and teaching of health professionals allowed for effective implementation of regional and national guidelines, with a significant impact on prescription patterns. This study shows promising results for prospective research on a national scale, including socioeconomical impact and cost‐effectiveness.
Health‐related Quality of Life in Infants With Chronic Liver Disease
Authors: Mohammad Saeed , Kaurs Elizabeth , Aguirre Vincent P. , Varni James W. , Alonso Estella M.
Published: December 2015

Objective:

The objective of the present study was to report on the health‐related quality of life (HRQOL) of infants with chronic liver disease using the PedsQL (Pediatric Quality of Life Inventory) Infant Scales.

Methods:

The 36‐item (ages 1–12 months) and 45‐item (ages 13–24 months) PedsQL Infant Scales (physical functioning, physical symptoms, emotional functioning, social functioning, cognitive functioning) were completed by 50 parents of infants with chronic liver disease.

Results:

Infants ages 1 to 12 months had significantly lower HRQOL scores compared with a matched healthy sample. Infants 13 to 24 months trended to lower physical HRQOL scores that did not reach statistical significance. Recent hospitalizations had an impact on the majority of HRQOL subscales, as did ascites, and failure to thrive.

Conclusions:

Infants ages 1 to 12 months with chronic liver disease demonstrate lower HRQOL compared with healthy children with physical subscales being most severely affected. The PedsQL Infant Scales allow the definition of HRQOL during a critical period of an infants’ development that has been heretofore difficult to measure.
An Ovarian Carcinoid Tumor With Peptide YY-Positive Insular Component: A Case Report and Review of the Literature
Authors: Erdenebaatar Chimeddulam , Yamaguchi Munekage , Saito Fumitaka , Motooka Chisato , Tashiro Hironori , Katabuchi Hidetaka
Published: December 2015

Ovarian carcinoid tumors are uncommon and account for 1% of all carcinoid tumors. The insular type of ovarian carcinoid tumor is common in western countries; in contrast, the strumal and trabecular types seem to be common in Asian countries. Strumal and trabecular types are associated with peptide YY (PYY) production, which may cause constipation. Here, we report the case of a 70-yr-old Japanese woman with chronic constipation who was referred to Kumamoto University Hospital because of a right adnexal mass. Imaging tests suggested that the solid mass might be malignant; therefore, abdominal total hysterectomy, bilateral salpingo-oophorectomy, and omentectomy were performed. A subsequent histopathologic examination confirmed an insular carcinoid tumor with a trabecular component in the right ovary. Both components were positive for PYY but not for serotonin. The patient complained of diarrhea instead of constipation soon after the surgery. Because PYY-positive insular carcinoid tumor in the ovary has not been previously reported, we reviewed 19 reported cases of patients with PYY-positive ovarian carcinoid tumors. The origins, common histologic types and symptoms caused by specific peptides secreted in ovarian carcinoid tumors differ between western and Asian countries.
Prevalence of Cognitive Impairment Without Dementia and Dementia in Tremembé, Brazil
Authors: César Karolina G. , Brucki Sonia M.D. , Takada Leonel T. , Nascimento Luiz F.C. , Gomes Camila M.S. , Almeida Milena C.S. , Oliveira Maira O. , Porto Fábio H.G. , Senaha Mirna L.H. , Bahia Valéria S. , Silva Thaís B.L. , Ianof Jéssica N. , Spíndola Lívia , Schmidt Magali T. , Jorge Mário S. , Vale Patrícia H.F. , Cecchini Mário A. , Cassimiro Luciana , Soares Roger T. , Gonçalves Márcia R. , Martins Ana C.S. , Daré Patrícia , Smid Jerusa , Porto Claudia S. , Carthery-Goulart Maria T. , Yassuda Mônica S. , Mansur Letícia L. , Nitrini Ricardo
Published: December 2015

Background:

The prevalence of cognitive impairment is insufficiently determined in developing countries. The aim of this study was to ascertain the prevalence of cognitive impairment without dementia and dementia in community-dwelling elderly in Brazil.

Methods:

This was a single-phase cross-sectional survey of the elderly (aged 60 years and above) living in the municipality of Tremembé, Brazil. Twenty percent of the households with elderly persons were randomly selected from urban and rural areas, to obtain a homogenous representation of all socioeconomic and cultural levels.

Results:

We assessed 630 individuals [mean age, 71.3 y (±7.99); mean years of education, 4.9 (±4.54)] and found prevalence rates of 17.5% (95% confidence interval, 14.6-20.6) for dementia and 19.5% (95% confidence interval, 16.6-22.8) for cognitive impairment without dementia. These prevalence rates were influenced by age (P<0.001) and by educational level (P<0.001). There was no significant sex difference among diagnostic groups (P=0.166). The prevalence of dementia was higher in relatively younger individuals (below 70 y) when compared with other studies. Besides, dementia was associated with low socioeconomic status, stroke, previous psychiatric disorder, alcoholism, and epilepsy.

Conclusions:

The prevalence of dementia in this study was higher than in other studies, particularly among younger elderly.
Evolution of sex chromosomes is prior to speciation in the dioeciousPhoenixspecies
Authors: Cherif Emira , Zehdi-Azouzi Salwa , Crabos Amandine , Castillo Karina , Chabrillange Nathalie , Pintaud Jean-Christophe , Salhi-Hannachi Amel , Glémin Sylvain , Aberlenc-Bertossi Frédérique
Published: December 2015

Understanding the driving forces and molecular processes underlying dioecy and sex chromosome evolution, leading from hermaphroditism to the occurrence of male and female individuals, is of considerable interest in fundamental and applied research. The genusPhoenix, belonging to the family Arecaceae, consists of only dioecious species. Phylogenetic data suggests that the genusPhoenixdiverged from a hermaphroditic ancestor shared with its closest relatives. Here we investigated the evolution of suppressed recombination within the genusPhoenixas a whole by extending the analysis ofP.dactyliferasex-related loci to eight other species within the genus. We also performed a phylogenetic analysis of a date palm sex-linkedPdMYB1gene in these species. We found that X and Y sex-linked alleles clustered in a species-independent fashion. Our data show that sex chromosomes evolved before the diversification of the extant dioecious species. Furthermore, the distribution of Y haplotypes revealed two male ancestral paternal lineages which may have emerged prior to speciation.
No evidence for extensive horizontal gene transfer in the genome of the tardigradeHypsibius dujardini
Authors: Koutsovoulos Georgios , Kumar Sujai , Laetsch Dominik R. , Stevens Lewis , Daub Jennifer , Conlon Claire , Maroon Habib , Thomas Fran , Aziz Aboobaker A. , Blaxter Mark
Published: December 2015

Tardigrades are meiofaunal ecdysozoans that are key to understanding the origins of Arthropoda. Many species of Tardigrada can survive extreme conditions through cryptobiosis. In a recent paper (Boothby TCet al(2015) Evidence for extensive horizontal gene transfer from the draft genome of a tardigrade.Proc Natl Acad Sci USA112:15976-15981) the authors concluded that the tardigradeHypsibius dujardinihad an unprecedented proportion (17%) of genes originating through functional horizontal gene transfer (fHGT), and speculated that fHGT was likely formative in the evolution of cryptobiosis. We independently sequenced the genome ofH. dujardini. As expected from whole-organism DNA sampling, our raw data contained reads from non-target genomes. Filtering using metagenomics approaches generated a draftH. dujardinigenome assembly of 135 Mb with superior assembly metrics to the previously published assembly. Additional microbial contamination likely remains. We found no support for extensive fHGT. Among 23,021 gene predictions we identified 0.2% strong candidates for fHGT from bacteria, and 0.2% strong candidates for fHGT from non-metazoan eukaryotes. Cross-comparison of assemblies showed that the overwhelming majority of HGT candidates in the Boothbyet al. genome derived from contaminants. We conclude that fHGT intoH. dujardiniaccounts for at most 1-2% of genes and that the proposal that one sixth of tardigrade genes originate from functional HGT events is an artefact of undetected contamination.
The glucose-sensing transcription factor MLX promotes myogenesis via myokine signaling
Authors: Hunt Liam C. , Xu Beisi , Finkelstein David , Fan Yiping , Carroll Patrick A. , Cheng Pei-Feng , Eisenman Robert N. , Demontis Fabio
Published: December 2015

Metabolic stress and changes in nutrient levels modulate many aspects of skeletal muscle function during aging and disease. Growth factors and cytokines secreted by skeletal muscle, known as myokines, are important signaling factors, but it is largely unknown whether they modulate muscle growth and differentiation in response to nutrients. Here, we found that changes in glucose levels increase the activity of the glucose-responsive transcription factor MLX (Max-like protein X), which promotes and is necessary for myoblast fusion. MLX promotes myogenesis not via an adjustment of glucose metabolism but rather by inducing the expression of several myokines, including insulin-like growth factor 2 (IGF2), whereas RNAi and dominant-negative MLX reduce IGF2 expression and block myogenesis. This phenotype is rescued by conditioned medium from control muscle cells and by recombinant IGF2, which activates the myogenic kinase Akt. Importantly, MLX-null mice display decreased IGF2 induction and diminished muscle regeneration in response to injury, indicating that the myogenic function of MLX is manifested in vivo. Thus, glucose is a signaling molecule that regulates myogenesis and muscle regeneration via MLX/IGF2/Akt signaling.
Motor neurons and oligodendrocytes arise from distinct cell lineages by progenitor recruitment
Authors: Ravanelli Andrew M. , Appel Bruce
Published: December 2015

During spinal cord development, ventral neural progenitor cells that express the transcription factors Olig1 and Olig2, called pMN progenitors, produce motor neurons and then oligodendrocytes. Whether motor neurons and oligodendrocytes arise from common or distinct progenitors in vivo is not known. Using zebrafish, we found that motor neurons and oligodendrocytes are produced sequentially by distinct progenitors that have distinct origins. When olig2+ cells were tracked during the peak period of motor neuron formation, most differentiated as motor neurons without further cell division. Using time-lapse imaging, we found that, as motor neurons differentiated, more dorsally positioned neuroepithelial progenitors descended to the pMN domain and initiated olig2 expression. Inhibition of Hedgehog signaling during motor neuron differentiation blocked the ventral movement of progenitors, the progressive initiation of olig2 expression, and oligodendrocyte formation. We therefore propose that the motor neuron-to-oligodendrocyte switch results from Hedgehog-mediated recruitment of glial-fated progenitors to the pMN domain subsequent to neurogenesis.
High telomerase is a hallmark of undifferentiated spermatogonia and is required for maintenance of male germline stem cells
Authors: Pech Matthew F. , Garbuzov Alina , Hasegawa Kazuteru , Sukhwani Meena , Zhang Ruixuan J. , Benayoun Bérénice A. , Brockman Stephanie A. , Lin Shengda , Brunet Anne , Orwig Kyle E. , Artandi Steven E.
Published: December 2015

Telomerase inactivation causes loss of the male germline in worms, fish, and mice, indicating a conserved dependence on telomere maintenance in this cell lineage. Here, using telomerase reverse transcriptase (Tert) reporter mice, we found that very high telomerase expression is a hallmark of undifferentiated spermatogonia, the mitotic population where germline stem cells reside. We exploited these high telomerase levels as a basis for purifying undifferentiated spermatogonia using fluorescence-activated cell sorting. Telomerase levels in undifferentiated spermatogonia and embryonic stem cells are comparable and much greater than in somatic progenitor compartments. Within the germline, we uncovered an unanticipated gradient of telomerase activity that also enables isolation of more mature populations. Transcriptomic comparisons of TertHigh undifferentiated spermatogonia and TertLow differentiated spermatogonia by RNA sequencing reveals marked differences in cell cycle and key molecular features of each compartment. Transplantation studies show that germline stem cell activity is confined to the TertHigh cKit− population. Telomere shortening in telomerase knockout strains causes depletion of undifferentiated spermatogonia and eventual loss of all germ cells after undifferentiated spermatogonia drop below a critical threshold. These data reveal that high telomerase expression is a fundamental characteristic of germline stem cells, thus explaining the broad dependence on telomerase for germline immortality in metazoans.
The Cleared Mammary Fat Pad Transplantation Assay for Mammary Epithelial Organogenesis
Authors: Lawson Devon A. , Werb Zena , Zong Yang , Goldstein Andrew S.
Published: December 2015

Cleared mammary fat pad (MFP) transplantation has been a standard technique for studies of mammary development and cancer for several decades. The mammary gland is comprised of several fundamental components: The epithelial compartment contains basal/myoepithelial cells and luminal cells, and the stromal compartment (called the MFP) contains adipocytes, smooth muscle cells, fibroblasts, and immune cells. In 3- to 4-wk-old female mice, the mammary epithelium is concentrated very close to the nipple and has not yet grown beyond the mammary lymph node to penetrate the bulk of the MFP. This developmental feature provides an anatomical fixed point, and enables one to cut away the portion of the MFP from the nipple to the lymph node, leaving behind the majority of the MFP free of epithelium. The “cleared” MFP can serve as a supportive native microenvironment fully sufficient for the organogenesis of injected donor epithelium. Normal mammary epithelial donor cells will produce histologically and functionally normal mammary ductal epithelium several weeks posttransplant, with the exception that the ducts will not be connected to the nipple. The assay described here provides a powerful platform for assessing the developmental and tumorigenic potential of engineered cells of interest.
The Saccharomyces Genome Database: Exploring Biochemical Pathways and Mutant Phenotypes
Authors: Cherry J. Michael
Published: December 2015

Many biochemical processes, and the proteins and cofactors involved, have been defined for the eukaryote Saccharomyces cerevisiae. This understanding has been largely derived through the awesome power of yeast genetics. The proteins responsible for the reactions that build complex molecules and generate energy for the cell have been integrated into web-based tools that provide classical views of pathways. The Yeast Pathways in the Saccharomyces Genome Database (SGD) is, however, the only database created from manually curated literature annotations. In this protocol, gene function is explored using phenotype annotations to enable hypotheses to be formulated about a gene’s action. A common use of the SGD is to understand more about a gene that was identified via a phenotypic screen or found to interact with a gene/protein of interest. There are still many genes that do not yet have an experimentally defined function and so the information currently available can be used to speculate about their potential function. Typically, computational annotations based on sequence similarity are used to predict gene function. In addition, annotations are sometimes available for phenotypes of mutations in the gene of interest. Integrated results for a few example genes will be explored in this protocol. This will be instructive for the exploration of details that aid the analysis of experimental results and the establishment of connections within the yeast literature.
Tissue Recombination Models for the Study of Epithelial Cancer
Authors: Zong Yang , Goldstein Andrew S. , Witte Owen N.
Published: December 2015

Animal models of cancer provide fundamental insight into the cellular and molecular mechanisms of human cancer development. As an alternative to genetically engineered mouse models, increasing evidence shows that tissue recombination and transplantation models represent an efficient approach to faithfully recapitulate solid epithelial cancer in mice. Cancer can be rapidly initiated through lentiviral delivery of defined genetic alterations into target cells that are grown in a physiological milieu with an appropriate epithelial–stromal interaction. Through genetic manipulation of distinct subpopulations of epithelial cells and mesenchymal cells, this powerful system can readily test both cell-autonomous roles of genetic events in the epithelial compartment and the paracrine effects of the microenvironment. Here we review the recent advances in mouse models of several epithelial cancers achieved using orthotopic transplantation and tissue recombination strategies, with an emphasis on the dissociated cell in vivo prostate regeneration model to investigate prostate cancer.
Purification of Early and Late Endosomes
Authors: de Araújo Mariana E.G. , Lamberti Giorgia , Huber Lukas A.
Published: December 2015

Proteomic analysis of early and late endosomes has been constrained by the limited purity of the endosomal fractions that can be achieved by biochemical methods. Here we briefly review endocytic pathways, and then introduce fractionation strategies that have been used to improve the purity of isolated endosomes. In addition, we describe innovative proteomics analysis methods that have been shown to partially circumvent the limitations found in the enrichment steps.
In vivopink-beam imaging and fast alignment procedure for rat brain tumor radiation therapy
Authors: Nemoz Christian , Kibleur Astrid , Hyacinthe Jean Noël , Berruyer Gilles , Brochard Thierry , Bräuer-Krisch Elke , Le Duc Géraldine , Brun Emmanuel , Elleaume Hélène , Serduc Raphaël
Published: December 2015

A fast positioning method for brain tumor microbeam irradiations for preclinical studies at third-generation X-ray sources is described. The three-dimensional alignment of the animals relative to the X-ray beam was based on the X-ray tomography multi-slices after iodine infusion. This method used pink-beam imaging produced by the ID17 wiggler. A graphical user interface has been developed in order to define the irradiation parameters: field width, height, number of angles and X-ray dose. This study is the first reporting an image guided method for soft tissue synchrotron radiotherapy. It allowed microbeam radiation therapy irradiation fields to be reduced by a factor of ∼20 compared with previous studies. It permitted more targeted, more efficient brain tumor microbeam treatments and reduces normal brain toxicity of the radiation treatment.
Local structure of Ge quantum dots determined by combined numerical analysis of EXAFS and XANES data
Authors: Zhang Yuanpeng , Ersoy Osman , Karatutlu Ali , Little William , Sapelkin Andrei
Published: December 2015

The sensitivity of X-ray absorption near-edge structure (XANES) to the local symmetry has been investigated in small (∼4 nm) matrix-free Ge quantum dots. TheFDMNESpackage was used to calculate the theoretical XANES spectra that were compared with the experimental data of as-prepared and annealed nanoparticles. It was found that XANES data for an as-prepared sample can only be adequately described if the second coordination shell of the diamond-type structural model is included in theFDMNEScalculations. This is in contrast to the extended X-ray absorption fine-structure data that show only the first-shell signal. These results suggest that, despite the high degree of disorder and a large surface-to-volume ratio, as-prepared small Ge quantum dots retain the diamond-type symmetry beyond the first shell. Furthermore, we utilized this sensitivity of XANES to the local symmetry to study annealed Ge quantum dots and found evidence for significant structural distortion which we attribute to the existence of surface disorder in the annealed oxygen-free Ge quantum dots.
Lithium chromium pyrophosphate as an insertion material for Li-ion batteries
Authors: Reichardt Martin , Sallard Sébastien , Novák Petr , Villevieille Claire
Published: December 2015

Lithium chromium pyrophosphate (LiCrP2O7) and carbon-coated LiCrP2O7 (LiCrP2O7/C) were synthesized by solid-state and sol–gel routes, respectively. The materials were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and conductivity measurements. LiCrP2O7 powder has a conductivity of ∼ 10−8 S cm−1, ∼ 104 times smaller than LiCrP2O7/C (∼ 10−4 S cm−1). LiCrP2O7/C is electrochemically active, mainly between 1.8 and 2.2 V versus Li+/Li (Cr3+/Cr2+ redox couple), whereas LiCrP2O7 has limited electrochemical activity. LiCrP2O7/C delivers a reversible specific charge up to ∼ 105 mAh g−1 after 100 cycles, close to the theoretical limit of 115 mAh g−1. Operando XRD experiments show slight peak shifts between 2.2 and 4.8 V versus Li+/Li, and a reversible amorphization between 1.8 and 2.2 V versus Li+/Li, suggesting an insertion reaction mechanism.
Crystal chemistry of hydrothermally grown ternary alkali rare earth fluorides
Authors: McMillen Colin D. , Comer Sara , Fulle Kyle , Sanjeewa Liurukara D. , Kolis Joseph W.
Published: December 2015

The structural variations of several alkali metal rare earth fluoride single crystals are summarized. Two different stoichiometric formulations are considered, namely those of ARE2F7 and ARE3F10 (A = K, Rb, Cs; RE = Y, La–Lu), over a wide range of ionic radii of both the alkali and rare earth (RE) ions. Previously reported and several new single-crystal structures are considered. The new single crystals are grown using hydrothermal methods and the structures are compared with literature reports of structures grown from both melts and hydrothermal fluids. The data reported here are combined with the literature data to gain a greater understanding of structural subtleties surrounding these systems. The work underscores the importance of the size of the cations to the observed structure type and also introduces synthetic technique as a contributor to the same. New insights based on single-crystal structure analysis in the work introduce a new disordered structure type in the case of ARE2F7, and examine the trends and boundaries of the ARE3F10 stoichiometry. Such fundamental structural information is useful in understanding the potential applications of these compounds as optical materials.
Photocrystallography and IR spectroscopy of light-induced linkage NO isomers in [RuBr(NO)2(PCyp3)2]BF4
Authors: Casaretto Nicolas , Pillet Sébastien , Bendeif El-Eulmi , Schaniel Dominik , Gallien Anna K. E. , Klüfers Peter , Woike Theo
Published: December 2015

One single photo-induced linkage NO isomer (PLI) is detected and characterized in the dinitrosyl pentacoordinated compound [RuBr(NO)2(PCyp3)2]BF4 by a combination of photocrystallographic and IR analysis. In the ground state, the molecule adopts a trigonal–bipyramidal structure with the two NO ligands almost linear with angles Ru—N1—O1 = 168.92 (16), Ru—N2—O2 = 166.64 (16)°, and exactly equal distances of Ru—N = 1.7838 (17) and O—N = 1.158 (2) Å. After light irradiation of 405 nm at T = 10 K, the angle of Ru—N2—O2 changes to 114.2 (6)° by rotation of the O atom towards the Br ligand with increased distances of Ru—N2 = 1.992 (6) and N2—O2 = 1.184 (8) Å, forming a bent κN bonded configuration. Using IR spectroscopy, the optimal wavelength and maximum population of 39 (1)% of the PLI is determined. In the ground state (GS), the two symmetric νs(NO) and asymmetric νas(NO) vibrations are measured at 1820 and 1778 cm−1, respectively. Upon photo-irradiation, the detection of only one new vibrational ν(NO) stretching band at 1655 cm−1, assigned to the antisymmetric coupled vibration mode and shifted to lower wavenumbers by −123 cm−1, supports the photocrystallographic result. These experimental results are supported by additional DFT calculations, which reproduce the structural parameters and vibrational properties of both the ground state and the photo-induced linkage isomer well. Especially the experimentally characterized molecular structure of the PLI state corresponds to an energy minimum in the calculations; the stabilization of the bent κN bonded configuration of the PLI state originates from specific intramolecular orbital overlap.
Crystal behavior of potassium bromate under compression
Authors: Santamaría-Pérez David , Chulia-Jordan Raquel , Rodríguez-Hernández Placida , Muñoz Alfonso
Published: December 2015

We report on high-pressure angle-dispersive X-ray diffraction data up to 15 GPa andab initiototal-energy calculations up to 242 GPa for KBrO3. No phase transition was found below 15 Pa in contrast to previously reported data. Its experimental bulk modulus in the quasi-hydrostatic regime isB0= 18.8 (9) GPa with a bulk modulus pressure derivativeB′0= 8.2 (4). However, according to ourab initiocalculations, KBrO3significantly reduces its rhombohedral distortionviasmall cooperative movements of the atoms and the structure progressively approaches the cubic symmetry, where the KBr subarray would adopt a topology similar to that of the corresponding B2-type bromide. This rearrangement of atoms is directly related to the Buerger's mechanism of theB1–B2 phase transition for halides, confirming that cations (second neighbors) do not arrange in an arbitrary way. The O atoms forming the [BrO3] pyramidal units move smoothly with pressure to the center of the [K8] cube faces, where electron localization function calculations present their maxima in otherB2-type compounds, eventually adopting the perovskite-type structure atP≃ 152 GPa. Our data on KBrO3has been compared with chemically substituted isostructural halates, providing new insights on the compressibility of this family of compounds.
The crystal chemistry of inorganic metal borohydrides and their relation to metal oxides
Authors: Černý Radovan , Schouwink Pascal
Published: December 2015

The crystal structures of inorganic homoleptic metal borohydrides are analysed with respect to their structural prototypes found amongst metal oxides in the inorganic databases such as Pearson's Crystal Data [Villars & Cenzual (2015). Pearson's Crystal Data. Crystal Structure Database for Inorganic Compounds, Release 2014/2015, ASM International, Materials Park, Ohio, USA]. The coordination polyhedra around the cations and the borohydride anion are determined, and constitute the basis of the structural systematics underlying metal borohydride chemistry in various frameworks and variants of ionic packing, including complex anions and the packing of neutral molecules in the crystal. Underlying nets are determined by topology analysis using the program TOPOS [Blatov (2006). IUCr CompComm. Newsl.
7, 4–38]. It is found that the Pauling rules for ionic crystals apply to all non-molecular borohydride crystal structures, and that the latter can often be derived by simple deformation of the close-packed anionic lattices c.c.p. and h.c.p., by partially removing anions and filling tetrahedral or octahedral sites. The deviation from an ideal close packing is facilitated in metal borohydrides with respect to the oxide due to geometrical and electronic considerations of the BH4
− anion (tetrahedral shape, polarizability). This review on crystal chemistry of borohydrides and their similarity to oxides is a contribution which should serve materials engineers as a roadmap to design new materials, synthetic chemists in their search for promising compounds to be prepared, and materials scientists in understanding the properties of novel materials.
Intrinsic flexibility of porous materials; theory, modelling and the flexibility window of the EMT zeolite framework
Authors: Fletcher Rachel E. , Wells Stephen A. , Leung Ka Ming , Edwards Peter P. , Sartbaeva Asel
Published: December 2015

Framework materials have structures containing strongly bonded polyhedral groups of atoms connected through their vertices. Typically the energy cost for variations of the inter-polyhedral geometry is much less than the cost of distortions of the polyhedra themselves – as in the case of silicates, where the geometry of the SiO4 tetrahedral group is much more strongly constrained than the Si—O—Si bridging angle. As a result, framework materials frequently display intrinsic flexibility, and their dynamic and static properties are strongly influenced by low-energy collective motions of the polyhedra. Insight into these motions can be obtained in reciprocal space through the `rigid unit mode' (RUM) model, and in real-space through template-based geometric simulations. We briefly review the framework flexibility phenomena in energy-relevant materials, including ionic conductors, perovskites and zeolites. In particular we examine the `flexibility window' phenomenon in zeolites and present novel results on the flexibility window of the EMT framework, which shed light on the role of structure-directing agents. Our key finding is that the crown ether, despite its steric bulk, does not limit the geometric flexibility of the framework.
A temperature-induced order–disorder phase transition in a 4-substituted 4,2′:6′,4′′-terpyridine
Authors: Granifo Juan , Westermeyer Marleen , Riquelme Maricel , Gaviño Rubén , Suárez Sebastián , Halac Emilia B. , Baggio Ricardo
Published: December 2015

Crystals of 4′-(isoquinolin-4-yl)-4,2′:6′,4′′-terpyridine (iqtp), C24H16N4, grown from an ethanol solution, undergo a reversible first-order single-crystal to single-crystal phase transition at T
c in the range 273–275 K, from a disordered higher-temperature phase [form (I)] in the space group P21/c, with one single molecule in the asymmetric unit, to an ordered lower-temperature one [form (II)] in the space group P21/n, with two independent molecules in the asymmetric unit. There is a group–subgroup relationship linking (I)–(II), due to cell doubling and the disappearance of a number of symmetry operations. In addition to X-ray diffraction, the transition has been monitored by Raman spectroscopy and differential scanning calorimetry, the latter disclosing an enthalpy change of 0.72 (6) kJ mol−1. Variations of the unit-cell parameters with temperature between 170 and 293 K are presented. The evolution of diffraction spots in the vicinity of the transition temperature shows the coexistence of both phases, confirming the first-order character of the transition. Structural details of both phases are analyzed and intermolecular interactions compared in order to investigate the mechanism of the phase transition. A three-dimensional Hirshfeld surface analysis was performed to corroborate the significant changes in the intermolecular features.
Disorder in the composite crystal structure of the manganese `disilicide' MnSi1.73from powder X-ray diffraction data
Authors: Akselrud L. , Cardoso Gil R. , Wagner-Reetz M. , Grin Yu.
Published: December 2015

The crystal structure of the higher manganese silicide MnSi1.7(known in the literature as HMS) is investigated in samples with different compositions obtained by different techniques at temperatures not higher than 1273 K. Powder X-ray diffraction was applied. The crystal structure is described as incommensurate composite. In addition to the ordered model already known in the literature, the partial disorder in the silicon substructure was detected and described introducing an additional atomic site with a different modulation function.
Structural diversity in hybrid organic–inorganic lead iodide materials
Authors: Weber Oliver J. , Marshall Kayleigh L. , Dyson Lewis M. , Weller Mark T.
Published: December 2015

The structural chemistry of hybrid organic–inorganic lead iodide materials has become of increasing significance for energy applications since the discovery and development of perovskite solar cells based on methylammonium lead iodide. Seven new hybrid lead iodide compounds have been synthesized and structurally characterized using single-crystal X-ray diffraction. The lead iodide units in materials templated with bipyridyl, 1,2-bis(4-pyridyl)ethane, 1,2-di(4-pyridyl)ethylene and imidazole adopt one-dimensional chain structures, while crystallization from solutions containing piperazinium cations generates a salt containing isolated [PbI6]4−octahedral anions. Templating with 4-chlorobenzylammonium lead iodide adopts the well known two-dimensional layered perovskite structure with vertex shared sheets of composition [PbI4]2−separated by double layers of organic cations. The relationships between the various structures determined, their compositions, stability and hydrogen bonding between the protonated amine and the iodide ions of the PbI6octahedra are described.