There is an increasing need for efficient phenotyping and histopathology of a variety of tissues. This phenotyping need is evident with the ambitious projects to disrupt every gene in the mouse ...genome. The research community needs rapid and inexpensive means to phenotype tissues via histology. Histological analyses of skeletal tissues are often time consuming and semi-quantitative at best, regularly requiring subjective interpretation of slides from trained individuals. Here, we present a cryohistological paradigm for efficient and inexpensive phenotyping of mineralized tissues. First, we present a novel method of tape-stabilized cryosectioning that preserves the morphology of mineralized tissues. These sections are then adhered rigidly to glass slides and imaged repeatedly over several rounds of staining. The resultant images are then aligned either manually or via computer software to yield composite stacks of several layered images. The protocol allows for co-localization of numerous molecular signals to specific cells within a given section. In addition, these fluorescent signals can be quantified objectively via computer software. This protocol overcomes many of the shortcomings associated with histology of mineralized tissues and can serve as a platform for high-throughput, high-content phenotyping of musculoskeletal tissues moving forward.
Students with disabilities experience poorer post-school outcomes compared with their peers without disabilities. Existing experimental literature on "what works" for improving these outcomes is ...rare; however, a rapidly growing body of research investigates correlational relationships between experiences in school and post-school outcomes. A meta-analytic review provides means for assessing which experiences show the strongest relationships with long-term outcomes and variability in these relationships by outcome, research design, and population. This article presents a meta-analysis of in-school predictors of postsecondary employment, education, and independent living of youth with disabilities, examining 35 sources and 27 samples (N = 16,957) published from January of 1984 through May of 2010. Predictors showed differing relationships with education versus employment. Some of the least studied predictors, especially those involving multistakeholder collaboration, had larger effects than predictors more typically the focus of correlational research. Implications for future research and practice are considered.
Fracture healing is a complex biological process involving the proliferation of mesenchymal progenitor cells, and chondrogenic, osteogenic, and angiogenic differentiation. The mechanisms underlying ...the proliferation and differentiation of mesenchymal progenitor cells remain unclear. Here, we demonstrate Dickkopf-related protein 3 (Dkk3) expression in periosteal cells using Dkk3–green fluorescent protein reporter mice. We found that proliferation of mesenchymal progenitor cells began in the periosteum, involving Dkk3-positive cell proliferation near the fracture site. In addition, Dkk3 was expressed in fibrocartilage cells together with smooth muscle α-actin and Col3.6 in the early phase of fracture healing as a cell marker of fibrocartilage cells. Dkk3 was not expressed in mature chondrogenic cells or osteogenic cells. Transient expression of Dkk3 disappeared in the late phase of fracture healing, except in the superficial periosteal area of fracture callus. The Dkk3 expression pattern differed in newly formed type IV collagen positive blood vessels and the related avascular tissue. This is the first report that shows Dkk3 expression in the periosteum at a resting state and in fibrocartilage cells during the fracture healing process, which was associated with smooth muscle α-actin and Col3.6 expression in mesenchymal progenitor cells. These fluorescent mesenchymal lineage cells may be useful for future studies to better understand fracture healing.
Cells are transplanted to regenerate an organs' parenchyma, but how transplanted parenchymal cells induce stromal regeneration is elusive. Despite the common use of a decellularized matrix, little is ...known as to the pivotal signals that must be restored for tissue or organ regeneration. We report that Alx3, a developmentally important gene, orchestrated adult parenchymal and stromal regeneration by directly transactivating Wnt3a and vascular endothelial growth factor. In contrast to the modest parenchyma formed by native adult progenitors, Alx3-restored cells in decellularized scaffolds not only produced vascularized stroma that involved vascular endothelial growth factor signalling, but also parenchymal dentin via the Wnt/β-catenin pathway. In an orthotopic large-animal model following parenchyma and stroma ablation, Wnt3a-recruited endogenous cells regenerated neurovascular stroma and differentiated into parenchymal odontoblast-like cells that extended the processes into newly formed dentin with a structure-mechanical equivalency to native dentin. Thus, the Alx3-Wnt3a axis enables postnatal progenitors with a modest innate regenerative capacity to regenerate adult tissues. Depleted signals in the decellularized matrix may be reinstated by a developmentally pivotal gene or corresponding protein.
A main goal of NASA's Kepler Mission is to establish the frequency of potentially habitable Earth-size planets ( ). Relatively few such candidates identified by the mission can be confirmed to be ...rocky via dynamical measurement of their mass. Here we report an effort to validate 18 of them statistically using the BLENDER technique, by showing that the likelihood they are true planets is far greater than that of a false positive. Our analysis incorporates follow-up observations including high-resolution optical and near-infrared spectroscopy, high-resolution imaging, and information from the analysis of the flux centroids of the Kepler observations themselves. Although many of these candidates have been previously validated by others, the confidence levels reported typically ignore the possibility that the planet may transit a star different from the target along the same line of sight. If that were the case, a planet that appears small enough to be rocky may actually be considerably larger and therefore less interesting from the point of view of habitability. We take this into consideration here and are able to validate 15 of our candidates at a 99.73% (3 ) significance level or higher, and the other three at a slightly lower confidence. We characterize the GKM host stars using available ground-based observations and provide updated parameters for the planets, with sizes between 0.8 and 2.9 R⊕. Seven of them (KOI-0438.02, 0463.01, 2418.01, 2626.01, 3282.01, 4036.01, and 5856.01) have a better than 50% chance of being smaller than 2 R⊕ and being in the habitable zone of their host stars.
The IMPC/KOMP program provides the opportunity to screen mice harboring well defined gene-inactivation mutations in a uniform genetic background. The program performs a global tissue phenotyping ...survey that includes skeletal x-rays and bone density measurements. Because of the relative insensitivity of the two screening tests for detecting variance in bone architecture, we initiated a secondary screen based on μCT and a cryohistolomorphological workflow that was performed on the femur and vertebral compartments on 220 randomly selected knockouts (KOs) and 36 control bone samples over a 2 1/2 year collection period provided by one of the production/phenotyping centers. The performance of the screening protocol was designed to balance throughput and cost versus sensitivity and informativeness such that the output would be of value to the skeletal biology community. Here we report the reliability of this screening protocol to establish criteria for control skeletal variance at the architectural, dynamic and cellular histomorphometric level. Unexpected properties of the control population include unusually high variance in BV/TV in male femurs and greater bone formation and bone turnover rates in the female femur and vertebral trabeculae bone compartments. However, the manner for maintaining bone formation differed between these two bone sites. The vertebral compartment relies on maintaining a greater number of bone forming surfaces while the femoral compartment utilized more matrix production per cell. The comparison of the architectural properties obtained by μCT and histomorphology revealed significant differences in values for BV/TV, Tb.Th and Tb.N which is attributable to sampling density of the two methods. However, as a screening tool, expressing the ratio of KO to the control line as obtained by either method was remarkably similar. It identified KOs with significant variance which led to a more detailed histological analysis. Our findings are exemplified by the Efna4 KO, in which a high BV/TV was identified by μCT and confirmed by histomorphometry in the femur but not in the vertebral compartment. Dynamic labeling showed a marked increase in BFR which was attributable to increased labeling surfaces. Cellular analysis confirmed partitioning of osteoblast to labeling surfaces and a marked decrease in osteoclastic activity on both labeling and quiescent surfaces. This pattern of increased bone modeling would not be expected based on prior studies of the Ephrin-Ephrin receptor signaling pathways between osteoblasts and osteoclasts. Overall, our findings underscore why unbiased screening is needed because it can reveal unknown or unanticipated genes that impact skeletal variation.
Two Earth―sized planets orbiting Kepler―20 FRESSIN, Francois; TORRES, Guillermo; CIARDI, David R ...
Nature (London),
02/2012, Letnik:
482, Številka:
7384
Journal Article
Recenzirano
Odprti dostop
Since the discovery of the first extrasolar giant planets around Sun-like stars, evolving observational capabilities have brought us closer to the detection of true Earth analogues. The size of an ...exoplanet can be determined when it periodically passes in front of (transits) its parent star, causing a decrease in starlight proportional to its radius. The smallest exoplanet hitherto discovered has a radius 1.42 times that of the Earth's radius (R(⊕)), and hence has 2.9 times its volume. Here we report the discovery of two planets, one Earth-sized (1.03R(⊕)) and the other smaller than the Earth (0.87R(⊕)), orbiting the star Kepler-20, which is already known to host three other, larger, transiting planets. The gravitational pull of the new planets on the parent star is too small to measure with current instrumentation. We apply a statistical method to show that the likelihood of the planetary interpretation of the transit signals is more than three orders of magnitude larger than that of the alternative hypothesis that the signals result from an eclipsing binary star. Theoretical considerations imply that these planets are rocky, with a composition of iron and silicate. The outer planet could have developed a thick water vapour atmosphere.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background
In osteosarcoma, patient survival has not changed in over 30 years. Multiple phase II trials have been conducted in osteosarcoma using the Response Evaluation Criteria in Solid Tumors ...(RECIST) as a primary endpoint; however, none of these have revealed new treatment strategies. We investigated RECIST in newly diagnosed patients who received neoadjuvant chemotherapy proven to be beneficial.
Methods
Patients treated from 1986 to 2011 for newly diagnosed osteosarcoma with paired tumor imaging before and after adequate neoadjuvant chemotherapy were included in this retrospective study. Two radiologists performed independent, blinded (to image timing) RECIST measurements of primary tumor and lung metastases at diagnosis and post‐neoadjuvant chemotherapy. Association between RECIST and histological necrosis and outcome were assessed.
Results
Seventy‐four patients met inclusion criteria. Five‐year overall survival and progression‐free survival (PFS) were 77 ± 7% and 61 ± 8%, respectively. No patients had RECIST partial or complete response in the primary tumor. Sixty‐four patients (86%) had stable disease, and 10 (14%) had progressive disease (PD). PD in the primary tumor was associated with significantly worse PFS in localized disease patients (P = 0.02). There was no association between RECIST in the primary tumor and necrosis. There were an insufficient number of patients with lung nodules ≥1 cm at diagnosis to evaluate RECIST in pulmonary metastases.
Conclusions
PD by RECIST predicts poor outcome in localized disease patients. In bone lesions, chemotherapy proven to improve overall survival does not result in radiographic responses as measured by RECIST. Further investigation of RECIST in pulmonary metastatic disease in osteosarcoma is needed.
Speciation leads to adaptive changes in organ cellular physiology and creates challenges for studying rare cell-type functions that diverge between humans and mice. Rare cystic fibrosis transmembrane ...conductance regulator (CFTR)-rich pulmonary ionocytes exist throughout the cartilaginous airways of humans
, but limited presence and divergent biology in the proximal trachea of mice has prevented the use of traditional transgenic models to elucidate ionocyte functions in the airway. Here we describe the creation and use of conditional genetic ferret models to dissect pulmonary ionocyte biology and function by enabling ionocyte lineage tracing (FOXI1-Cre
::ROSA-TG), ionocyte ablation (FOXI1-KO) and ionocyte-specific deletion of CFTR (FOXI1-Cre
::CFTR
). By comparing these models with cystic fibrosis ferrets
, we demonstrate that ionocytes control airway surface liquid absorption, secretion, pH and mucus viscosity-leading to reduced airway surface liquid volume and impaired mucociliary clearance in cystic fibrosis, FOXI1-KO and FOXI1-Cre
::CFTR
ferrets. These processes are regulated by CFTR-dependent ionocyte transport of Cl
and HCO
. Single-cell transcriptomics and in vivo lineage tracing revealed three subtypes of pulmonary ionocytes and a FOXI1-lineage common rare cell progenitor for ionocytes, tuft cells and neuroendocrine cells during airway development. Thus, rare pulmonary ionocytes perform critical CFTR-dependent functions in the proximal airway that are hallmark features of cystic fibrosis airway disease. These studies provide a road map for using conditional genetics in the first non-rodent mammal to address gene function, cell biology and disease processes that have greater evolutionary conservation between humans and ferrets.
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