Is the Clinician's Eye a Valid and Reproducible Tool for Diagnosing Patella Alta on a Lateral Knee Radiography?

INTRODUCTION: Validity and reproducibility of the clinician's eye (CE) to diagnose patella alta (PA) on a lateral knee radiography (radiograph) is unknown. METHODS: Cross-sectional study of 46 lateral knee x-rays. Three blind observers used CE, Insall-Salvati (IS), modified Insall-Salvati (mIS), and Caton-Deschamps (C-D) to determine patellar height. Sensitivity and specificity of each observer was compared with the musculoskeletal radiologist's C-D measurements. Intraobserver and interobserver agreement were assessed with intraclass correlation coefficient and Fleiss κ, respectively. Time needed to estimate patellar height for every method was recorded in seconds. Statistical differences between observers were calculated with a generalized estimating equation. Analysis of variance and post hoc Bonferroni test compared duration of each method (P < 0.05). Data were analyzed using Stata 15 (StataCorp). RESULTS: CE, IS, mIS, and C-D's sensitivity and specificity values are as follows: 77%, 92%; 94%, 52%; 67%, 58%; and 53%, 89%, respectively. Intraclass correlation coefficient and Fleiss κ of CE, IS, mIS, and C-D values are as follows: 0.66 and 0.43, 0.88 and 0.68, 0.54 and 0.09, and 0.68 and 0.59, respectively. CE was the second most sensitive and most specific method for diagnosis of PA, with moderate intraobserver and interobserver agreement. IS was the most sensitive method with good intraobserver and interobserver agreement. CE was significantly faster (P < 0.05) than all other conventional radiographic ratios. CONCLUSION: CE's sensitivity increases with observer's experience and is highly specific. If normal patellar height is diagnosed, no other ratios are necessary, even in the less experienced clinician. Intraobserver and interobserver reproducibilities were moderate and only inferior to the IS ratio. In case patellar height is uncertain with the CE, the IS ratio is the most sensitive and reproducible method to confirm the diagnosis of PA.

BeerDeCoded: the open beer metagenome project.

Next generation sequencing has radically changed research in the life sciences, in both academic and corporate laboratories. The potential impact is tremendous, yet a majority of citizens have little or no understanding of the technological and ethical aspects of this widespread adoption. We designed BeerDeCoded as a pretext to discuss the societal issues related to genomic and metagenomic data with fellow citizens, while advancing scientific knowledge of the most popular beverage of all. In the spirit of citizen science, sample collection and DNA extraction were carried out with the participation of non-scientists in the community laboratory of Hackuarium, a not-for-profit organisation that supports unconventional research and promotes the public understanding of science. The dataset presented herein contains the targeted metagenomic profile of 39 bottled beers from 5 countries, based on internal transcribed spacer (ITS) sequencing of fungal species. A preliminary analysis reveals the presence of a large diversity of wild yeast species in commercial brews. With this project, we demonstrate that coupling simple laboratory procedures that can be carried out in a non-professional environment, with state-of-the-art sequencing technologies and targeted metagenomic analyses, can lead to the detection and identification of the microbial content in bottled beer.

PPARß interprets a chromatin signature of pluripotency to promote embryonic differentiation at gastrulation.

Epigenetic post-transcriptional modifications of histone tails are thought to help in coordinating gene expression during development. An epigenetic signature is set in pluripotent cells and interpreted later at the onset of differentiation. In pluripotent cells, epigenetic marks normally associated with active genes (H3K4me3) and with silent genes (H3K27me3) atypically co-occupy chromatin regions surrounding the promoters of important developmental genes. However, it is unclear how these epigenetic marks are recognized when cell differentiation starts and what precise role they play. Here, we report the essential role of the nuclear receptor peroxisome proliferator-activated receptor ß (PPARß, NR1C2) in Xenopus laevis early development. By combining loss-of-function approaches, large throughput transcript expression analysis by the mean of RNA-seq and intensive chromatin immunoprecipitation experiments, we unveil an important cooperation between epigenetic marks and PPARß. During Xenopus laevis gastrulation PPARß recognizes H3K27me3 marks that have been deposited earlier at the pluripotent stage to activate early differentiation genes. Thus, PPARßis the first identified transcription factor that interprets an epigenetic signature of pluripotency, in vivo, during embryonic development. This work paves the way for a better mechanistic understanding of how the activation of hundreds of genes is coordinated during early development.

PPAR modulation of kinase-linked receptor signaling in physiology and disease.

Kinase-linked receptors and nuclear receptors connect external cues to gene transcription. Among nuclear receptors, peroxisome proliferator-activated receptors (PPARs) are of special interest in relation to widespread human diseases. Mapping out connections between PPARs and kinase-linked receptor signaling is central to better understand physiological and pathophysiological processes and to better define therapeutic strategies. This is the aim of the present review.

Fatty acid synthesis and PPARalpha hand in hand.

How can an ex-orphan be adopted? Is it possible to do so by attributing to it a key endogenous ligand that regulates its central functions? In the recent issue of Cell, Chakravarthy et al. attempted to answer this question by characterizing a new physiologically relevant ligand for the ex-orphan receptor peroxisome proliferator activated receptor alpha (PPARalpha).

A dialogue between the SIRENE pathway in synergids and the fertilization independent seed pathway in the central cell controls male gamete release during double fertilization in Arabidopsis.

Angiosperms sexual reproduction involves interactions between the two female gametes in the embryo sac and the two male gametes released by the pollen tube. The two synergids of the embryo sac express the FERONIA/SIRENE receptor-like kinase, which controls the discharge of the two sperm cells from the pollen tube. FER/SRN may respond to a ligand from the pollen tube. Alternatively, the interaction between FER/SRN and a ligand from the embryo sac may lead to a state of competence of the synergids allowing pollen tube discharge. Here, we report the new mutant scylla (syl) impaired in the control of pollen tube discharge. This mutant also produces autonomous endosperm development in absence of fertilization-a trait associated with the FERTILIZATION INDEPENDENT SEED (FIS) mutant class. This led us to identify autonomous endosperm in srn mutants and to demonstrate synergistic interactions between srn and the fis mutants. In addition, the fis mutants display defects in pollen tube discharge as in srn and syl mutants, confirming the interaction between the two pathways. Our findings suggest that pollen tube discharge is controlled by an interaction between the synergids expressing SRN/FER and the central cell expressing FIS genes.

A novel class of MYB factors controls sperm-cell formation in plants.

In contrast to animals, the plant male germline is established after meiosis in distinctive haploid structures, termed pollen grains. The germline arises by a distinct asymmetric division of the meiotic products . The fates of the resulting vegetative and generative cells are distinct. In contrast to the larger vegetative cell, arrested in the G1 phase of the cell cycle, the smaller generative cell divides once to produce the two male gametes or sperm cells. Sperm cells are delivered to the female gametes by the pollen tube, which develops from the vegetative cell. In spite of recent efforts to understand pollen development , the molecular pathway controlling sperm-cell ontogenesis is unknown. Here, we present the isolation of DUO1, a novel R2R3 MYB gene of Arabidopsis, as the first gene shown to control male gamete formation in plants. DUO1 is specifically expressed in the male germline, and DUO1 protein accumulates in sperm-cell nuclei. Mutations in DUO1 produce a single larger diploid sperm cell unable to perform fertilization. DUO1 appears to be evolutionarily conserved in several plant species and defines a new subfamily of pollen-specific MYB genes.

Female control of male gamete delivery during fertilization in Arabidopsis thaliana.

Fertilization in both animals and plants relies on the correct targeting of the male gametes to the female gametes. In flowering plants, the pollen tube carries two male gametes through the maternal reproductive tissues to the embryo sac, which contains two female gametes. The pollen tube then releases its two male gametes into a specialized receptor cell of the embryo sac, the synergid cell. The mechanisms controlling this critical step of gamete delivery are unknown. Here, data based on the new sirène (srn) mutant of Arabidopsis thaliana provide the first evidence for female control over male gamete delivery. Live imaging of fertilization shows that wild-type pollen tubes do not stop their growth and do not deliver their contents in srn embryo sacs.

Fertilization in Arabidopsis thaliana wild type: developmental stages and time course.

We describe some previously uncharacterised stages of fertilization in Arabidopsis thaliana and provide for the first time a precise time course of the fertilization process. We hand-pollinated wild type pistils with wild type pollen (Columbia ecotype), fixed them at various times after pollination, and analysed 600 embryo sacs using Confocal Laser Scanning Microscopy. Degeneration of one of the synergid cells starts at 5 Hours After Pollination (HAP). Polarity of the egg changes rapidly after this synergid degeneration. Karyogamy is then detected by the presence of two nucleoli of different diameters in both the egg and central cell nuclei, 7-8 HAP. Within the next hour, first nuclear division takes place in the fertilized central cell and two nucleoli can then be seen transiently in each nucleus produced. In a second set of experiments, we hand-pollinated wild type pistils with pollen from a transgenic promLAT52::EGFP line that expresses EGFP in its pollen vegetative cell. Release of the pollen tube contents into the synergid cell could be detected in living material. We show that the timing of synergid degeneration and pollen tube release correlate well, suggesting that either the synergid cell degenerates at the time of pollen tube discharge or very shortly before it. These observations and protocols constitute an important basis for the further phenotypic analysis of mutants affected in fertilization.