581 research outputs found

    Intra-Messinian truncation surface in the Levant Basin explained by subaqueous dissolution

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    The Messinian salinity crisis (MSC) is an extreme event in Earth history during which a salt giant (>1 × 106 km3) accumulated on the Mediterranean seafloor within ~640 k.y. Erosional unconformities extending from the continental margins into the deep basins are key features for reconstructing the MSC; however, the nature of the erosional processes and their subaerial versus subaqueous origin are highly controversial. This study focuses on the top erosion surface (TES) in the deep Levant Basin, which is notably flat, truncating a basinward-tilted Messinian evaporitic succession. Based on high-resolution seismic surveys and wireline logs, we show that (1) the TES is actually an intra-Messinian truncation surface (IMTS) located ~100 m below the Messinian-Zanclean boundary; (2) the topmost, post-truncation Messinian unit is very different from the underlying salt deposits and consists mostly of shale, sand, and anhydrite; and (3) the flat IMTS is a dissolution surface related to significant dilution and stratification of the water column during the transition from stage 2 to stage 3 of the MSC. Dissolution occurred upslope where salt rocks at the seabed were exposed to the upper diluted brine, while downslope, submerged in the deeper halite-saturated layer, the salt rocks were preserved. The model, which requires a stratified water column, is inconsistent with a complete desiccation of the eastern Mediterranean Sea

    Infections with Avian Pathogenic and Fecal Escherichia coli Strains Display Similar Lung Histopathology and Macrophage Apoptosis

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    The purpose of this study was to compare histopathological changes in the lungs of chickens infected with avian pathogenic (APEC) and avian fecal (Afecal) Escherichia coli strains, and to analyze how the interaction of the bacteria with avian macrophages relates to the outcome of the infection. Chickens were infected intratracheally with three APEC strains, MT78, IMT5155, and UEL17, and one non-pathogenic Afecal strain, IMT5104. The pathogenicity of the strains was assessed by isolating bacteria from lungs, kidneys, and spleens at 24 h post-infection (p.i.). Lungs were examined for histopathological changes at 12, 18, and 24 h p.i. Serial lung sections were stained with hematoxylin and eosin (HE), terminal deoxynucleotidyl dUTP nick end labeling (TUNEL) for detection of apoptotic cells, and an anti-O2 antibody for detection of MT78 and IMT5155. UEL17 and IMT5104 did not cause systemic infections and the extents of lung colonization were two orders of magnitude lower than for the septicemic strains MT78 and IMT5155, yet all four strains caused the same extent of inflammation in the lungs. The inflammation was localized; there were some congested areas next to unaffected areas. Only the inflamed regions became labeled with anti-O2 antibody. TUNEL labeling revealed the presence of apoptotic cells at 12 h p.i in the inflamed regions only, and before any necrotic foci could be seen. The TUNEL-positive cells were very likely dying heterophils, as evidenced by the purulent inflammation. Some of the dying cells observed in avian lungs in situ may also be macrophages, since all four avian E. coli induced caspase 3/7 activation in monolayers of HD11 avian macrophages. In summary, both pathogenic and non-pathogenic fecal strains of avian E. coli produce focal infections in the avian lung, and these are accompanied by inflammation and cell death in the infected areas

    Cell arrest and cell death in mammalian preimplantation development

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    The causes, modes, biological role and prospective significance of cell death in preimplantation development in humans and other mammals are still poorly understood. Early bovine embryos represent a very attractive experimental model for the investigation of this fundamental and important issue. To obtain reference data on the temporal and spatial occurrence of cell death in early bovine embryogenesis, three-dimensionally preserved embryos of different ages and stages of development up to hatched blastocysts were examined in toto by confocal laser scanning microscopy. In parallel, transcript abundance profiles for selected apoptosis-related genes were analyzed by real-time reverse transcriptase-polymerase chain reaction. Our study documents that in vitro as well as in vivo, the first four cleavage cycles are prone to a high failure rate including different types of permanent cell cycle arrest and subsequent non-apoptotic blastomere death. In vitro produced and in vivo derived blastocysts showed a significant incidence of cell death in the inner cell mass (ICM), but only in part with morphological features of apoptosis. Importantly, transcripts for CASP3, CASP9, CASP8 and FAS/FASLG were not detectable or found at very low abundances. In vitro and in vivo, errors and failures of the first and the next three cleavage divisions frequently cause immediate embryo death or lead to aberrant subsequent development, and are the main source of developmental heterogeneity. A substantial occurrence of cell death in the ICM even in fast developing blastocysts strongly suggests a regular developmentally controlled elimination of cells, while the nature and mechanisms of ICM cell death are unclear. Morphological findings as well as transcript levels measured for important apoptosis-related genes are in conflict with the view that classical caspase-mediated apoptosis is the major cause of cell death in early bovine development

    A Prediction Model to Prioritize Individuals for a SARS-CoV-2 Test Built from National Symptom Surveys

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    Background: The gold standard for COVID-19 diagnosis is detection of viral RNA through PCR. Due to global limitations in testing capacity, effective prioritization of individuals for testing is essential. Methods: We devised a model estimating the probability of an individual to test positive for COVID-19 based on answers to 9 simple questions that have been associated with SARS-CoV-2 infection. Our model was devised from a subsample of a national symptom survey that was answered over 2 million times in Israel in its first 2 months and a targeted survey distributed to all residents of several cities in Israel. Overall, 43,752 adults were included, from which 498 self-reported as being COVID-19 positive. Findings: Our model was validated on a held-out set of individuals from Israel where it achieved an auROC of 0.737 (CI: 0.712–0.759) and auPR of 0.144 (CI: 0.119–0.177) and demonstrated its applicability outside of Israel in an independently collected symptom survey dataset from the US, UK, and Sweden. Our analyses revealed interactions between several symptoms and age, suggesting variation in the clinical manifestation of the disease in different age groups. Conclusions: Our tool can be used online and without exposure to suspected patients, thus suggesting worldwide utility in combating COVID-19 by better directing the limited testing resources through prioritization of individuals for testing, thereby increasing the rate at which positive individuals can be identified. Moreover, individuals at high risk for a positive test result can be isolated prior to testing. Funding: E.S. is supported by the Crown Human Genome Center, Larson Charitable Foundation New Scientist Fund, Else Kroener Fresenius Foundation, White Rose International Foundation, Ben B. and Joyce E. Eisenberg Foundation, Nissenbaum Family, Marcos Pinheiro de Andrade and Vanessa Buchheim, Lady Michelle Michels, and Aliza Moussaieff and grants funded by the Minerva foundation with funding from the Federal German Ministry for Education and Research and by the European Research Council and the Israel Science Foundation. H.R. is supported by the Israeli Council for Higher Education (CHE) via the Weizmann Data Science Research Center and by a research grant from Madame Olga Klein – Astrachan

    Marked alveolar apoptosis/proliferation imbalance in end-stage emphysema

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    BACKGROUND: Apoptosis has recently been proposed to contribute to the pathogenesis of emphysema. METHODS: In order to establish if cell fate plays a role even in end-stage disease we studied 16 lungs (9 smoking-associated and 7 α1antitrypsin (AAT)-deficiency emphysema) from patients who had undergone lung transplantations. Six unused donor lungs served as controls. Apoptosis was evaluated by TUNEL analysis, single-stranded DNA laddering, electron microscopy and cell proliferation by an immunohistochemical method (MIB1). The role of the transforming growth factor (TGF)-β1 pathway was also investigated and correlated with epithelial cell turnover and with the severity of inflammatory cell infiltrate. RESULTS: The apoptotic index (AI) was significantly higher in emphysematous lungs compared to the control group (p ≤ 0.01), particularly if only lungs with AAT-deficiency emphysema were considered (p ≤ 0.01 vs p = 0.09). The proliferation index was similar in patients and controls (1.9 ± 2.2 vs 1.7 ± 1.1). An increased number of T lymphocytes was observed in AAT-deficiency lungs than smoking-related cases (p ≤ 0.05). TGF-β1 expression in the alveolar wall was higher in patients with smoking-associated emphysema than in cases with AAT-deficiency emphysema (p ≤ 0.05). A positive correlation between TGF-βRII and AI was observed only in the control group (p ≤ 0.005, r(2 )= 0.8). A negative correlation was found between the TGF-β pathway (particularly TGF-βRII) and T lymphocytes infiltrate in smoking-related cases (p ≤ 0.05, r(2 )= 0.99) CONCLUSION: Our findings suggest that apoptosis of alveolar epithelial cells plays an important role even in end-stage emphysema particularly in AAT-deficiency disease. The TGFβ-1 pathway does not seem to directly influence epithelial turnover in end-stage disease. Inflammatory cytokine different from TGF-β1 may differently orchestrate cell fate in AAT and smoking-related emphysema types

    213Bi-PAI2 conjugate selectively induces apoptosis in PC3 metastatic prostate cancer cell line and shows anti-cancer activity in a xenograft animal model

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    A novel α-particle emitting (213Bi) plasminogen activator inhibitor type 2 construct, which targets the membrane-bound urokinase plasminogen activator on prostate cancer cells, was prepared and evaluated in vitro and in a xenograft animal model. The PC3 prostate cancer cell line expresses urokinase plasminogen activator which binds to its receptor on the cell membrane; plasminogen activator inhibitor type 2 is bound to urokinase plasminogen activator/urokinase plasminogen activator receptor to form stable complexes. In vitro, the cytotoxicity of 213Bi-plasminogen activator inhibitor type 2 against prostate cancer cells was tested using the MTS assay and apoptosis was documented using terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labelling (TUNEL) assay. In vivo, antiproliferative effects for tumours and prostate cancer lymph node metastasis were carried out in an athymic nude mouse model with a subcutaneous xenograft of PC3 cells. 213Bi-plasminogen activator inhibitor type 2 was specifically cytotoxic to PC3 cells in a concentration-dependent fashion, causing the cells to undergo apoptosis. A single local or i.p. injection of 213Bi-plasminogen activator inhibitor type 2 was able to completely regress the growth of tumours and lymph node metastases 2 days post subcutaneous inoculation, and obvious tumour regression was achieved in the therapy groups compared with control groups with 213Bi-plasminogen activator inhibitor type 2 when the tumours measured 30–40 mm3 and 85–100 mm3. All control animals and one of five (20%) mice treated with 3 mCi kg−1 213Bi-plasminogen activator inhibitor type 2 developed metastases in the lymph nodes while no lymphatic spread of cancer was found in the 6 mCi kg−1 treated groups at 2 days and 2 weeks post-cell inoculation. These results demonstrate that this novel 213Bi-plasminogen activator inhibitor type 2 conjugate selectively targets prostate cancer in vitro and in vivo, and could be considered for further development for the therapy of prostate cancer, especially for the control of micro-metastases or in minimal residual disease

    Taurine: a potential marker of apoptosis in gliomas

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    New cancer therapies are being developed that trigger tumour apoptosis and an in vivo method of apoptotic detection and early treatment response would be of great value. Magnetic resonance spectroscopy (MRS) can determine the tumour biochemical profile in vivo, and we have investigated whether a specific spectroscopic signature exists for apoptosis in human astrocytomas. High-resolution magic angle spinning (HRMAS) 1H MRS provided detailed 1H spectra of brain tumour biopsies for direct correlation with histopathology. Metabolites, mobile lipids and macromolecules were quantified from presaturation HRMAS 1H spectra acquired from 41 biopsies of grades II (n=8), III (n=3) and IV (n=30) astrocytomas. Subsequently, TUNEL and H&E staining provided quantification of apoptosis, cell density and necrosis. Taurine was found to significantly correlate with apoptotic cell density (TUNEL) in both non-necrotic (R=0.727, P=0.003) and necrotic (R=0.626, P=0.0005) biopsies. However, the ca 2.8 p.p.m. polyunsaturated fatty acid peak, observed in other studies as a marker of apoptosis, correlated only in non-necrotic biopsies (R=0.705, P<0.005). We suggest that the taurine 1H MRS signal in astrocytomas may be a robust apoptotic biomarker that is independent of tumour necrotic status

    The synthetic inhibitor of Fibroblast Growth Factor Receptor PD166866 controls negatively the growth of tumor cells in culture

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    <p>Abstract</p> <p>Background</p> <p>Many experimental data evidence that over-expression of various growth factors cause disorders in cell proliferation. The role of the Fibroblast Growth Factors (FGF) in growth control is indisputable: in particular, FGF1 and its tyrosine kinase receptor (FGFR1) act through a very complex network of mechanisms and pathways. In this work we have evaluated the antiproliferative activity effect of PD166866, a synthetic molecule inhibiting the tyrosin kinase action of FGFR1.</p> <p>Methods</p> <p>Cells were routinely grown in Dulbecco Modified Eagle's medium supplemented with newborn serum and a penicillin-streptomycin mixture.</p> <p>Cell viability was evaluated by Mosmann assay and by trypan blue staining. DNA damage was assessed by <it>in situ </it>fluorescent staining with Terminal Deoxynucleotidyl Transferase dUTP nick end labeling (TUNEL assay).</p> <p>Assessment of oxidative stress at membrane level was measured by quantitative analysis of the intra-cellular formation of malonyl-dialdheyde (MDA) deriving from the decomposition of poly-unsaturated fatty acids.</p> <p>The expression of Poly-ADP-Ribose-Polymerase (PARP), consequent to DNA fragmentation, was evidenced by immuno-histochemistry utilizing an antibody directed against an N-terminal fragment of the enzyme.</p> <p>Results</p> <p>The bioactivity of the drug was investigated on Hela cells. Cytoxicity was assessed by the Mosmann assay and by vital staining with trypan blue. The target of the molecule is most likely the cell membrane as shown by the significant increase of the intracellular concentration of malonyl-dihaldheyde. The increase of this compound, as a consequence of the treatment with PD166866, is suggestive of membrane lipoperoxidation. The TUNEL assay gave a qualitative, though clear, indication of DNA damage. Furthermore we demonstrate intracellular accumulation of poly-ADP-ribose polymerase I. This enzyme is a sensor of nicks on the DNA strands and this supports the idea that treatment with the drug induces cell death.</p> <p>Conclusions</p> <p>Data presented in this work show that PD166866 has clear antiproliferative effects. The negative control of cell proliferation may be exerted through the activation of the apoptotic pathway. The results of experiments addressing this specific point, such as: evaluation of DNA damage, lipoperoxidation of the cell membrane and increase of expression of PARP, an enzyme directly involved in DNA repair. Results suggest that cells exposed to PD16866 undergo apoptosis. However, concomitant modes of cell death cannot be ruled out. The possible use of this drug for therapeutic purposes is discussed.</p

    In vivo Recombinant Adenovirus-mediated p53 Gene Therapy in a Syngeneic Rat Model for Colorectal Cancer

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    The p53 gene has a significant role in controlling genomic stability of cancer. The purpose of this study was to evaluate the tumor response of allograft colorectal tumor treated with Ad5CMV-p53 in a syngeneic rat model. Two weeks after the inoculation of WB-2054-M5 tumor cells in the flank of rats, rats were randomly assigned by tumor size to one of three groups (n=18 in each): phosphate buffered saline (PBS), Ad5CMV, and Ad5CMV-p53. Recombinant adenovirus or PBS was administered through intratumoral injection at three divided doses every other day for 4 weeks. Apoptosis of the tumors was evaluated using TUNEL assay. After 2 and 4 weeks of treatment, the volume (cm3) of tumors in PBS, Ad5CMV, and Ad5CMV-p53 was as follows: 2 week: 1.66Âą0.43, 1.40Âą0.47, 0.75Âą0.26 (p<0.001), 4 week: 4.41Âą0.88, 3.93Âą1.86, 2.33Âą0.51 (p<0.001). Tumor growth showed no statistically significant difference between the PBS and Ad5CMV groups (6-week vol. p=0.32). The TUNEL assay results revealed more apparent apoptotic cells in Ad5CMV-p53-treated tumors than in other groups. Growth of allograft colorectal cancer in the syngeneic rat model was significantly suppressed by intratumoral Ad5CMV-p53 gene therapy. These results demonstrate that gene replacement therapy with p53 may provide a novel modality of treatment in conjunction with other present treatments for metastatic colorectal cancer
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