Development of an animal experimental model to study the effects of levonorgestrel on the human endometrium

BACKGROUND: This study was designed to develop an animal model to test the response of endometrium to local progestin delivery. METHODS: Proliferative human endometrium was subcutaneously grafted in two groups of SCID mice that received, 2 days before, a subcutaneous estradiol (E2) pellet and, for half of them, an additional implant of levonorgestrel (LNG). Mice were sacrificed 1, 2, 3 or 4 weeks after endometrial implantation and grafts were histologically analysed. Proliferation, steroid hormone receptors, blood vessels and stromal decidualization in both groups (E2 and LNG) were immunohistologically evaluated and compared with proliferative endometrium and endometrium from women with an LNG intrauterine device. RESULTS: Grafts presented normal morphological endometrial characteristics. The expression of progesterone receptors was significantly decreased in glands and stroma of the LNG group as compared with the E2 group at all times. A significant decrease was also observed in the stromal expression of estrogen receptor- in the LNG group. At 4 weeks, the mean cross-sectional area of vessels was significantly higher after LNG treatment. CONCLUSIONS: These morphological and immunohistochemical characteristics are similar to those observed in women treated with local LNG. This mouse model might facilitate further investigations needed to understand the mechanisms responsible for the breakthrough bleeding frequently observed in progestin users

Reduction in Phencyclidine Induced Sensorimotor Gating Deficits in the Rat Following Increased System Xc − Activity in the Medial Prefrontal Cortex

Rationale: Aspects of schizophrenia, including deficits in sensorimotor gating, have been linked to glutamate dysfunction and/or oxidative stress in the prefrontal cortex. System xc −, a cystine–glutamate antiporter, is a poorly understood mechanism that contributes to both cellular antioxidant capacity and glutamate homeostasis. Objectives: Our goal was to determine whether increased system xc − activity within the prefrontal cortex would normalize a rodent measure of sensorimotor gating. Methods: In situ hybridization was used to map messenger RNA (mRNA) expression of xCT, the active subunit of system xc −, in the prefrontal cortex. Prepulse inhibition was used to measure sensorimotor gating; deficits in prepulse inhibition were produced using phencyclidine (0.3–3 mg/kg, sc). N-Acetylcysteine (10–100 μM) and the system xc − inhibitor (S)-4-carboxyphenylglycine (CPG, 0.5 μM) were used to increase and decrease system xc − activity, respectively. The uptake of 14C-cystine into tissue punches obtained from the prefrontal cortex was used to assay system xc − activity. Results: The expression of xCT mRNA in the prefrontal cortex was most prominent in a lateral band spanning primarily the prelimbic cortex. Although phencyclidine did not alter the uptake of 14C-cystine in prefrontal cortical tissue punches, intraprefrontal cortical infusion of N-acetylcysteine (10–100 μM) significantly reduced phencyclidine- (1.5 mg/kg, sc) induced deficits in prepulse inhibition. N-Acetylcysteine was without effect when coinfused with CPG (0.5 μM), indicating an involvement of system xc −. Conclusions: These results indicate that phencyclidine disrupts sensorimotor gating through system xc − independent mechanisms, but that increasing cystine–glutamate exchange in the prefrontal cortex is sufficient to reduce behavioral deficits produced by phencyclidine

Defining Developmental Potency and Cell Lineage Trajectories by Expression Profiling of Differentiating Mouse Embryonic Stem Cells

Biologists rely on morphology, function and specific markers to define the differentiation status of cells. Transcript profiling has expanded the repertoire of these markers by providing the snapshot of cellular status that reflects the activity of all genes. However, such data have been used only to assess relative similarities and differences of these cells. Here we show that principal component analysis of global gene expression profiles map cells in multidimensional transcript profile space and the positions of differentiating cells progress in a stepwise manner along trajectories starting from undifferentiated embryonic stem (ES) cells located in the apex. We present three ‘cell lineage trajectories’, which represent the differentiation of ES cells into the first three lineages in mammalian development: primitive endoderm, trophoblast and primitive ectoderm/neural ectoderm. The positions of the cells along these trajectories seem to reflect the developmental potency of cells and can be used as a scale for the potential of cells. Indeed, we show that embryonic germ cells and induced pluripotent cells are mapped near the origin of the trajectories, whereas mouse embryo fibroblast and fibroblast cell lines are mapped near the far end of the trajectories. We suggest that this method can be used as the non-operational semi-quantitative definition of cell differentiation status and developmental potency. Furthermore, the global expression profiles of cell lineages provide a framework for the future study of in vitro and in vivo cell differentiation

Clinical and immunohistochemical study of eight cases with thymic carcinoma

BACKGROUND: Thymic carcinoma is a rare neoplasm with extremely poor prognosis. To evaluate the biological characteristics of thymic carcinoma, we reviewed 8 patients. METHODS: There were 2 men and 6 women: ages ranged from 19 to 67 years old (mean 54.8 years). None of these patients had concomitant myasthenia gravis and pure red cell aplasia. No patient had stage I disease, 1 stage II, 5 stage III, and 2 stage IV. The pathologic subtypes of thymic carcinoma included 5 squamous cell carcinomas, 1 adenosquamous cell carcinomas, 1 clear cell carcinoma, and 1 small cell carcinoma. Immunohistochemical study was performed using antibodies against p53, bcl-2, Ki-67, carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), nm23-H1, vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF-2) and factor VIII. RESULTS: Curative resection could be done in 4 patients (50%). Our data indicates a trend toward an association between complete resection and patient survival. Expression of p53, bcl-2, CEA, EMA, nm23-H1, VEGF and FGF-2 was detected in 5/8, 3/8, 4/8, 5/8, 6/8, 5/8 and 3/8, respectively. Mean Ki-67 labeling index and microvessel density was 7.01 and 34.36 (per 200× field), respectively. When compared with our previous studies, immunohistochemical staining of these proteins in thymomas, the expression rates of these proteins in thymic carcinomas were higher than those in thymomas. CONCLUSIONS: In this small series, it is suggested that a complete resection suggests a favorable result. Immunohistochemical results reveal that the expression of these proteins might indicate the aggressiveness of thymic carcinoma

Early glandular neoplasia of the lung

Although bronchogenic carcinomas progress through a very well defined sequence of metaplasia, dysplasia and carcinoma in situ, very little is known about the early progression of glandular neoplasms of the lung. In particular, the early precursor lesion from which fully malignant adenocarcinomas arise has effectively eluded recognition, at least until recently. Several lines of evidence now implicate atypical adenomatous hyperplasia (AAH) as an initial morphologic stage in multistep lung tumorigenesis. Despite its small size, AAH can be appreciated at the light microscopic level and characterized at the molecular genetic level. Indeed, the genetic characterization of AAH promises to further our understanding of lung cancer development and might facilitate the design of novel strategies for early detection of lung cancer

Functional Heterogeneity of Embryonic Stem Cells Revealed through Translational Amplification of an Early Endodermal Transcript

Detection of low-level, lineage-specific transcription aids in the identification of lineage-primed populations of ES cells provides a new framework for pluripotency

Isolation of Oct4-Expressing Extraembryonic Endoderm Precursor Cell Lines

BACKGROUND:The extraembryonic endoderm (ExEn) defines the yolk sac, a set of membranes that provide essential support for mammalian embryos. Recent findings suggest that the committed ExEn precursor is present already in the embryonic Inner Cell Mass (ICM) as a group of cells that intermingles with the closely related epiblast precursor. All ICM cells contain Oct4, a key transcription factor that is first expressed at the morula stage. In vitro, the epiblast precursor is most closely represented by the well-characterized embryonic stem (ES) cell lines that maintain the expression of Oct4, but analogous ExEn precursor cell lines are not known and it is unclear if they would express Oct4. METHODOLOGY/PRINCIPAL FINDINGS:Here we report the isolation and characterization of permanently proliferating Oct4-expressing rat cell lines ("XEN-P cell lines"), which closely resemble the ExEn precursor. We isolated the XEN-P cell lines from blastocysts and characterized them by plating and gene expression assays as well as by injection into embryos. Like ES cells, the XEN-P cells express Oct4 and SSEA1 at high levels and their growth is stimulated by leukemia inhibitory factor, but instead of the epiblast determinant Nanog, they express the ExEn determinants Gata6 and Gata4. Further, they lack markers characteristic of the more differentiated primitive/visceral and parietal ExEn stages, but exclusively differentiate into these stages in vitro and contribute to them in vivo. CONCLUSIONS/SIGNIFICANCE:Our findings (i) suggest strongly that the ExEn precursor is a self-renewable entity, (ii) indicate that active Oct4 gene expression (transcription plus translation) is part of its molecular identity, and (iii) provide an in vitro model of early ExEn differentiation

Distinct Peripheral Blood RNA Responses to Salmonella in Pigs Differing in Salmonella Shedding Levels: Intersection of IFNG, TLR and miRNA Pathways

Transcriptomic analysis of the response to bacterial pathogens has been reported for several species, yet few studies have investigated the transcriptional differences in whole blood in subjects that differ in their disease response phenotypes. Salmonella species infect many vertebrate species, and pigs colonized with Salmonella enterica serovar Typhimurium (ST) are usually asymptomatic, making detection of these Salmonella-carrier pigs difficult. The variable fecal shedding of Salmonella is an important cause of foodborne illness and zoonotic disease. To investigate gene pathways and biomarkers associated with the variance in Salmonella shedding following experimental inoculation, we initiated the first analysis of the whole blood transcriptional response induced by Salmonella. A population of pigs (n = 40) was inoculated with ST and peripheral blood and fecal Salmonella counts were collected between 2 and 20 days post-inoculation (dpi). Two groups of pigs with either low shedding (LS) or persistent shedding (PS) phenotypes were identified. Global transcriptional changes in response to ST inoculation were identified by Affymetrix Genechip® analysis of peripheral blood RNA at day 0 and 2 dpi. ST inoculation triggered substantial gene expression changes in the pigs and there was differential expression of many genes between LS and PS pigs. Analysis of the differential profiles of gene expression within and between PS and LS phenotypic classes identified distinct regulatory pathways mediated by IFN-γ, TNF, NF-κB, or one of several miRNAs. We confirmed the activation of two regulatory factors, SPI1 and CEBPB, and demonstrated that expression of miR-155 was decreased specifically in the PS animals. These data provide insight into specific pathways associated with extremes in Salmonella fecal shedding that can be targeted for further exploration on why some animals develop a carrier state. This knowledge can also be used to develop rational manipulations of genetics, pharmaceuticals, nutrition or husbandry methods to decrease Salmonella colonization, shedding and spread