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Context.—Digital pathology using whole slide images has been recently approved for primary diagnosis in clinical surgical pathology practices. Here we describe a novel imaging method, fluorescence-imitating brightfield imaging, that can capture the surface of fresh tissue without requiring prior fixation, paraffin embedding, tissue sectioning, or staining.Objective.—To compare the ability of pathologists to evaluate direct-to-digital images with standard pathology preparations.Design.—One hundred surgical pathology samples were obtained. Samples were first digitally imaged, then processed for standard histologic examination on 4-μm hematoxylin-eosin-stained sections and digitally scanned. The resulting digital images from both digital and standard scan sets were viewed by each of 4 reading pathologists. The data set consisted of 100 reference diagnoses and 800 study pathologist reads. Each study read was compared to the reference diagnosis, and also compared to that reader's diagnosis across both modalities.Results.—The overall agreement rate, across 800 reads, was 97.9%. This consisted of 400 digital reads at 97.0% versus reference and 400 standard reads versus reference at 98.8%. Minor discordances (defined as alternative diagnoses without clinical treatment or outcome implications) were 6.1% overall, 7.2% for digital, and 5.0% for standard.Conclusions.—Pathologists can provide accurate diagnoses from fluorescence-imitating brightfield imaging slide-free images. Concordance and discordance rates are similar to published rates for comparisons of whole slide imaging to standard light microscopy of glass slides for primary diagnosis. It may be possible, therefore, to develop a slide-free, nondestructive approach for primary pathology diagnosis.

While in vivo methods for disease detection and classification, including radiology and liquid biopsy, continue to improve with respect to spatial resolution (radiology) and molecular information, they have not, to [...], * Context.--Digital pathology using whole slide images has been recently approved to support primary diagnosis in clinical surgical pathology practices. Here we describe a novel imaging method, fluorescence-imitating brightfield imaging, that can capture the surface of fresh tissue without requiring prior fixation, paraffin embedding, tissue sectioning, or staining. Objective.--To compare the ability of pathologists to evaluate direct-to-digital images with standard pathology preparations. Design.--One hundred surgical pathology samples were obtained. Samples were first digitally imaged, then processed for standard histologic examination on 4-im hematoxylin-eosin-stained sections and digitally scanned. The resulting digital images from both digital and standard scan sets were viewed by each of 4 reading pathologists. The data set consisted of 100 reference diagnoses and 800 study pathologist reads. Each study read was compared to the reference diagnosis, and also compared to that reader's diagnosis across both modalities. Results.--The overall agreement rate, across 800 reads, was 97.9%. This consisted of 400 digital reads at 97.0% versus reference and 400 standard reads versus reference at 98.8%. Minor discordances (defined as alternative diagnoses without clinical treatment or outcome implications) were 6.1% overall, 7.2% for digital, and 5.0% for standard. Conclusions.--Pathologists can provide accurate diagnoses from fluorescence-imitating brightfield imaging slide-free images. Concordance and discordance rates are similar to published rates for comparisons of whole slide imaging to standard light microscopy of glass slides for primary diagnosis. It may be possible, therefore, to develop a slide-free, nondestructive approach for primary pathology diagnosis.

Characteristics of maternal vascular malperfusion (MVM) are frequently observed in placentas from pregnancies impacted by preeclampsia, intrauterine growth restriction, preterm labor, and intrauterine fetal demise. We sought to evaluate the associations of features of MVM with subclinical measures of cardiovascular health and coagulation potential in healthy young women. Sixty-three healthy young women were recruited and assessed prior to pregnancy on cycle day 9 ± 4, at gestational age 90 ± 6 of early pregnancy, and gestational age 216 ± 5 of late pregnancy. Women were assessed for plasma volume, blood pressure, response to volume loading, cardiac output, and uterine hemodynamics. Platelet-poor plasma was collected to assess thrombin generation on a subset of 33 women at all time points. Following delivery, placentas were collected and analyzed for evidence of MVM. Thrombin generation (TG) was evaluated in the presence of tissue factor (TF) with and without recombinant soluble thrombomodulin (TM). For each, we compared TG lagtime, peak level, and endogenous thrombin potential (ETP). Comparisons were made between dichotomized presence and absence of each individual feature of MVM and cardiovascular and coagulation features. Mean ± standard deviation are presented. Women were 31 ± 4 years of age, body mass index of 24 ± 5 kg/m2, 86% white race, and 80% nulliparous. MVM occurred in 70% of placentas, with infarcts and agglutination (44%), decidual arteriopathy (40%), accelerated villous maturation (32%), placental hypoplasia (29%), and distal villous hypoplasia (17%) documented. Decidual arteriopathy and distal villous hypoplasia were associated with prepregnancy maternal physiology, including decreased plasma volume and subclinical cardiovascular variations. All assessed MVM characteristics had identifiable early pregnancy physiologic characteristics consistent with altered cardiovascular function and decreased uterine response to pregnancy when compared with women who did and did not develop MVM. Accelerated villous maturation was the only MVM feature to differ by thrombin generation parameters in early pregnancy. Thrombin generation potential and blood pressure were elevated in late pregnancy in women who developed decidual arteriopathy. Prepregnancy health status and adaptation to pregnancy play important roles in pregnancy outcomes. Both cardiovascular health and thrombin generation potential may influence early placentation. Longitudinal assessment of subclinical maternal factors may allow for better understanding of the etiologies of MVM lesions, as well as allow for identification of a timeline of the origins of placental pathologies.

Introduction Diploid eukaryotes normally have two genomes, one from each parent, from which for generative reproduction, complete haploid sets of chromosomes (genomes) must be derived. This is realized in meiosis. [...], Meiosis is the basis of the generative reproduction of eukaryotes. The crucial first step is homologous chromosome pairing. In higher eukaryotes, micrometer-scale chromosomes, micrometer distances apart, are brought together by nanometer DNA sequences, at least a factor of 1000 size difference. Models of homology search, homologue movement, and pairing at the DNA level in higher eukaryotes are primarily based on studies with yeast where the emphasis is on the induction and repair of DNA double-strand breaks (DSB). For such a model, the very large nuclei of most plants and animals present serious problems. Homology search without DSBs cannot be explained by models based on DSB repair. The movement of homologues to meet each other and make contact at the molecular level is not understood. These problems are discussed and the conclusion is that at present practically nothing is known of meiotic homologue pairing in higher eukaryotes up to the formation of the synaptonemal complex, and that new, necessarily speculative models must be developed. Arguments are given that RNA plays a central role in homology search and a tentative model involving RNA in homology search is presented. A role of actin in homologue movement is proposed. The primary role of DSBs in higher eukaryotes is concluded to not be in paring but in the preparation of Holliday junctions, ultimately leading to chromatid exchange. Keywords: meiosis higher eukaryotes, homologue pairing, double-strand DNA breaks, RNA, chromosome pairing model, chromatid exchange. La meiose constitue l'assise de la reproduction generative chez les eucaryotes. Une premiere etape cruciale est l'appariement des chromosomes homologues. Chez les chromosomes des eucaryotes superieurs, mesurant des micrometres et separes par de semblables distances, des sequences de l'ordre du nanometre en assurent le rapprochement, soit une difference d'au moins 1000 fois. Chez les eucaryotes, les modeles de la recherche d'homologie, du mouvement des homologues et de l'appariement au niveau de l'ADN ont principalement ete realisees chez la levure, ou l'emphase est placee sur l'induction et la reparation de bris bicatenaires (ou DSB pour 'double-strand breaks'). Dans un tel modele, les tres grands noyaux rencontres chez la plupart des especes vegetales et animales posent de serieux problemes. La recherche d'homologie sans DSB ne peut s'expliquer par des modeles fondes sur la reparation des DSB. Ainsi, le mouvement des homologues pour assurer leur rencontre et contact n'est pas compris au niveau moleculaire. Ces problemes sont discutes par l'auteur et celui-ci conclut que pratiquement rien n'est connu presentement sur l'appariement des homologues chez les eucaryotes superieurs jusqu'au moment de la formation du complexe synaptonemal. En consequence, de nouveaux modeles, forcement speculatifs, doivent etre mis au point. Des arguments sont presentes a l'effet que l'ARN jouerait un role central dans la recherche d'homologie et un modele provisoire octroyant a l'ARN un role dans la recherche d'homologie est mis de l'avant. Un role pour l'actine dans le mouvement des homologues est propose. L'auteur conclut que le role premier des DSB chez les eucaryotes superieurs serait non pas dans l'appariement mais dans la preparation des jonctions de Holliday, lesquelles menent ultimement a l'echange de chromatides. [Traduit par la Redaction] Mots-cles : meiose eucaryotes superieurs, appariement d'homologues, cassures d'ADN double brin, ARN, modele d'appariement chromosomique, echange de chromatides.

We studied twelve late Holocene organic deposits in West-Frisia, The Netherlands. Pollen, spores, non-pollen palynomorphs, mosses, other botanical macrofossils and insect remains were recorded for reconstructions of changing environmental conditions. Eastern West-Frisia was a cultivated landscape during the Bronze Age, but it became a freshwater wetland in the Late Bronze Age. In most of our sites, radiocarbon dates show that time transgressive inundation of soils preceded the climate shift at 850 cal BC for several centuries. We suggest that solar forcing of climate change may have delivered the final push to the inundation and depopulation of West-Frisia, which had already commenced several centuries before, due to sealevel rise. We did not find evidence for significant Bronze Age tree growth in West-Frisia before the inundations. Vegetation successions in the new wetlands developed from shallow mineral-rich freshwater to rich-fen vegetation. Subsequently poor fen vegetation with birch and pine developed, and the natural succession led to ombrotrophic raised bog vegetation. Complete successions from shallow, mineral-rich lakes to raised bog lasted between 1000 and 1500 calendar years. We hypothesize that medieval drainage and reclamation became possible only when the mires of West-Frisia had reached the raised bog stage. Reclamation of raised bogs by medieval farmers (drainage, eutrophication, peat digging) caused compaction, oxidation and loss of the upper part of the peat deposit. Seeds of salt-tolerant and salt-demanding plant species indicate that the medieval sites were inundated during storm surges with brackish or salt water, which triggered the farmers to build artificial mounds and, later, dikes. Under mounds and dikes, peat deposits remained protected against further decay. With our data we deliver a long-term perspective on contemporary ecosystem dynamics of freshwater wetlands, relevant for nature conservation and future climate change.

Introduction In meiosis the homologous chromosomes pair to form bivalents. Each chromosome consists of two chromatids. Pairing is completed with the formation of the synaptonemal complex where recombinational chromatid exchange [...], To prevent unbalanced chromosome segregation, meiotic metaphase I - anaphase I transition is carefully regulated by delaying anaphase until all kinetochores are well oriented (anaphase checkpoint) in mammals and insects. In plants this has not yet been established. In heterozygotes of two reciprocal translocations of Secale cereale, with one chromosome replaced by its two telocentric arms, anaphase delay was correlated with the orientation of the kinetochores of the complex of five chromosomes. The terminal kinetochores of the half chromosomes were readily elongated and pole oriented. Chains of five chromosomes with all five kinetochores orienting on alternate poles where the first to start anaphase. Kinetochores of two adjacent chromosomes when oriented on the same pole were partly shielded and less well pole directed. Anaphase was delayed. Cells with this configuration accumulated during anther development. Kinetochores in metacentric chromosomes lacking chiasmata in one arm (in trivalents and bivalents) were slightly better pole oriented and delayed anaphase less. Release of chromatid cohesion as triggered by kinetochore stretch is apparently delayed by inadequate exposition and pole orientation of the kinetochores. It is a mild form of an anaphase checkpoint, in normal material synchronizing bivalent segregation. Key words: meiosis, multivalent orientation, kinetochore activity, anaphase checkpoint, Secale. Afin de prevenir une segregation chromosomique inegale au cours de la meiose, la transition metaphase I - anaphase I est etroitement regulee en retardant l'anaphase I jusqu'a ce que tous les kinetochores soient bien orientes (checkpoint de l'anaphase) chez les animaux et les insectes. Chez les plantes, cela n'a pas encore ete demontre. Chez des plantes de seigle (Secale cereale) heterozygotes pour deux translocations reciproques, ou l'un des chromosomes etait remplace par deux bras telocentriques, le delai a l'entree en anaphase etait correle avec l'orientation des kinetochores du complexe forme de cinq chromosomes. Les kinetochores terminaux des demi-chromosomes etaient facilement etires et orientes vers les poles. Les chaines formees de cinq chromosomes avec les cinq kinetochores orientes en direction de poles alternes ont ete les premieres a marquer le debut de l'anaphase. Les kinetochores de deux chromosomes adjacents, lorsqu'ils etaient orientes vers le meme pole, etaient partiellement voiles et moins bien orientes vers le pole. L'anaphase etait retardee dans ces cas. Les cellules presentant cette configuration s'accumulaient au cours du developpement des antheres. Les kinetochores situes sur des chromosomes metacentriques auxquels il manquait des chiasmas sur un bras (au sein de trivalents ou de bivalents) etaient legerement mieux orientes vers les poles et entrainaient un moindre delai a l'entree en anaphase. Le relachement de la cohesion des chromatides, declenche par Retirement des kinetochores, etait apparemment retarde par une exposition et une orientation polaire inadequates des kinetochores. Il s'agit d'une forme faible de checkpoint de l'anaphase, lequel permet de synchroniser la segregation des bivalents chez un materiel normal. [Traduit par la Redaction] Mots-cles: meiose, orientation des multivalents, activite des kinetochores, checkpoint de l'anaphase, Secale.

Introduction Detailed reports on variation in meiotic behaviour within individual organisms are rare. Sybenga et al. (2008) reported on the variation between tillers of single plants of rye (Secale cereale [...], Meiotic metaphase I configuration frequencies were determined in different tillers of genetically related plants of rye (Secale cereale L.) heterozygous for reciprocal translocation T248W (between chromosome arms 1RS and 6RS) and with an additional (telocentric) arm 1RS. Seventeen different configurations could be recognized, grouped into three categories. Very different configuration frequencies were found not only between sister plants from the same parents but also between tillers of the same plant grown under identical conditions (climate chambers at 15°C and 20°C). The heterogeneity reflects variation in chromosome pairing and crossing over, and is variable and unpredictable. Anthers within florets were homogeneous. Between tiller heterogeneity is insufficient to explain differences between sister plants. It is ascribed to random somatic variation in the conditions of the chromatin which, at meiosis, govern chromosome pairing. During sexual differentiation, these conditions are fixed and subsequent cell lineages have the same pairing and crossing over characteristics. As homology search is an activity of DNA, this control of pairing and crossing over, consistent over long cell lineages, may be considered to be epigenetic even when no realistic suggestions concerning its character can be given. Key words: translocation heterozygote, single-arm-trisomiy, Secale, meiosis, intraplant heterogeneity. Les frequences des configurations observees lors de la metaphase I de la meiose ont ete mesurees au sein de differents talles de chacun de plusieurs plants de seigle (Secale cereale L.) genetiquement apparentes et heterozygotes pour la translocation reciproque T248W (entre bras chromosomiques 1RS et 5RS) ainsi que porteurs d'un bras (telocentrique) 1RS additionnel. Dix-sept configurations differentes ont ete distinguees et formaient trois categories. Des frequences tres differentes de ces configurations ont ete observees non seulement entre plantes soeurs ayant les memes parents, mais aussi entre talles de la meme plante cultivee dans des conditions identiques (chambres de croissance a 15°C ou 20°C). Cette heterogeneite reflete de la variation au niveau de l' appariement chromosomique et des enjambements, est variable et imprevisible. Les antheres au sein d' une fleur etaient homogenes. L' heterogeneite observee entre talles etait insuffisante pour expliquer les differences entre plantes soeurs. Ces dernieres sont plutot attribuees a une variation somatique aleatoire dans l' etat de la chromatine qui, lors de la meiose, determinerait l' appariement. Au cours de la differenciation sexuelle, ces conditions seraient fixees et les lignees cellulaires derivees partageraient les memes caracteristiques en matiere d'appariement et de recombinaison. Comme la recherche d'homologie est un processus qui depend de l'ADN, on peut considerer ce controle de l' appariement et de l' enjambent, conserve tout au long de lignees cellulaires, comme etant un processus epigenetique bien qu'aucune hypothese realiste concernant sa nature ne puisse etre mise de l'avant. Mots-cles : heterozygote pour une translocation, trisomie pour un seul bras, Secale, meiose, heterogeneite intra- plante. [Traduit par la Redaction]

Introduction There is an increasing interest in manipulating crossing over recombination in plant breeding (Wijnker and de Jong 2008). A special situation is the close linkage between a gene and [...], Chromosomal rearrangements, including reciprocal translocations, may prevent recombinational transfer of genes from a donor genotype to a recipient, especially when the gene is located in an interstitial segment. The effect of trisomy of chromosome arm 1RS on recombination was studied in translocation heterozygote T248W of rye (Secale cereale), involving chromosome arms 1RS and 6RS. (Pro)metaphase I configuration frequencies were analyzed. Crossing over, estimated as chiasma parameters, in five genetically different euploid heterozygotes was compared with those of 10 different single arm trisomics. The addition of 1RS greatly altered the crossing over pattern around the translocation break point, with a special increase in the interstitial segment of 6RS and adjoining regions, normally hardly accessible to recombination. Furthermore, there was considerable variation between plants of closely related genotypes. Heterogeneity widens the distribution of crossing overs, including segments normally not accessible to recombination, but decreases average recombination in other segments. The extra chromosome and abnormal segregants are eliminated by using the trisomic as the pollen parent. Key words: recombination increase, translocation heterozygote, single-arm trisomic, interstitial segment, Secale. Les rearrangements chromosomiques, incluant les translocations reciproques, peuvent empecher le transfert de genes par voie de recombinaison d'un genotype donneur a un receveur, particulierement lorsque le gene est situe sur un segment interne. L'effet sur la recombinaison de la trisomie pour le bras chromosomique 1RS a ete etudie chez une lignee heterozygote pour la translocation T248W chez le seigle (Secale cereale), laquelle implique les bras chromosomiques 1RS et 6RS. Les frequences des configurations en (pro)metaphase I ont ete analysees. Les enjambements estimes sur la base des parametres des chiasmas chez cinq heterozygotes euploides genetiquement distincts ont ete compares a ceux observes chez 10 lignees differentes trisomiques pour un seul bras. L'ajout de 1RS a grandement altere la recombinaison autour du point de jonction de la translocation, un accroissement particulier etant observe au sein du segment interne du 6RS et les regions voisines, lesquelles sont normalement peu sujettes a la recombinaison. Il y avait une variation considerable entre plantes ayant des genotypes tres proches. L' heterogeneite augmentait la distribution des enjambements, incluant des segments normalement peu accessibles a la recombinaison, mais diminuait la frequence moyenne de recombinaison au sein des autres segments. Le chromosome additionnel ainsi que les segregants anormaux sont elimines en employant la lignee transgenique comme parent male. Mots-cles : augmentation de la recombinaison, heterozygote pour une translocation, trisomie pour un seul bras, segment interne, Secale. [Traduit par la Redaction]

In telocentric trisomics (telotrisomics) of organisms in which the chromosomes normally have two distinct arms, a single chromosome arm with a centromere is present in addition to a complete diploid set of chromosomes. It is the simplest form of polysomy and suitable for analyzing meiotic pairing and recombination patterns in situations where chromosomes compete for pairing. When no suitable meiotic chromosome markers are available, four metaphase I configurations can be distinguished. Their relative frequencies are indicative of the pairing and recombination patterns. In short arm (1RS) telotrisomics of chromosome 1R of rye (Secale cereale) we observed great differences in pairing and recombination patterns among spikes from different tillers and clones of the same plants. Anthers within spikes were only very rarely different. We analyzed a large number of genotypes, including inbreds as well as hybrids. The effects of genetic and environmental conditions on heterogeneity, if any, were limited. Considering that the reproductive tissue of a spike is derived from one primordial cell, it seems that at the start of sexual differentiation there was variation among cells in chromosomal control, which at meiosis determines pairing and crossing-over competence. We suggest that it is an epigenetic system that rigidly maintains this pattern through generative differentiation. In competitive situations the combination most competent for pairing will pair preferentially, forming specific meiotic configurations with different frequencies for different spikes of the same plant. This would explain the heterogeneity between spikes and the homogeneity within spikes. The epigenetic system could involve chromatin conformation or DNA methylation. There were no signs of heterochromatinization.

Telocentric trisomics (telotrisomics; one arm of a metacentric chromosome present in addition to two complete genomes) are used in theoretical studies of pairing affinities and chiasma formation in competitive situations [...]