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81.
Angélica R. Cappellari Micheli M. Pillat Hellio D. N. Souza Fabrícia Dietrich Francine H. Oliveira Fabrício Figueiró Ana L. Abujamra Rafael Roesler Joanna Lecka Jean Sévigny Ana Maria O. Battastini Henning Ulrich 《PloS one》2015,10(10)
Background
Ecto-5’-nucleotidase/CD73 (ecto-5’-NT) participates in extracellular ATP catabolism by converting adenosine monophosphate (AMP) into adenosine. This enzyme affects the progression and invasiveness of different tumors. Furthermore, the expression of ecto-5’-NT has also been suggested as a favorable prognostic marker, attributing to this enzyme contradictory functions in cancer. Medulloblastoma (MB) is the most common brain tumor of the cerebellum and affects mainly children.Materials and Methods
The effects of ecto-5’-NT overexpression on human MB tumor growth were studied in an in vivo model. Balb/c immunodeficient (nude) 6 to 14-week-old mice were used for dorsal subcutaneous xenograph tumor implant. Tumor development was evaluated by pathophysiological analysis. In addition, the expression patterns of adenosine receptors were verified.Results
The human MB cell line D283, transfected with ecto-5’-NT (D283hCD73), revealed reduced tumor growth compared to the original cell line transfected with an empty vector. D283hCD73 generated tumors with a reduced proliferative index, lower vascularization, the presence of differentiated cells and increased active caspase-3 expression. Prominent A1 adenosine receptor expression rates were detected in MB cells overexpressing ecto-5’-NT.Conclusion
This work suggests that ecto-5’-NT promotes reduced tumor growth to reduce cell proliferation and vascularization, promote higher differentiation rates and initiate apoptosis, supposedly by accumulating adenosine, which then acts through A1 adenosine receptors. Therefore, ecto-5’-NT might be considered an important prognostic marker, being associated with good prognosis and used as a potential target for therapy. 相似文献82.
The Perceived Temperature (PT) is an equivalent temperature based on a complete heat budget model of the human body. It has
proved its suitability for numerous applications across a wide variety of scales from micro to global and is successfully
used both in daily forecasts and climatological studies. PT is designed for staying outdoors and is defined as the air temperature
of a reference environment in which the thermal perception would be the same as in the actual environment. The calculation
is performed for a reference subject with an internal heat production of 135 W m−2 (who is walking at 4 km h−1 on flat ground). In the reference environment, the mean radiant temperature equals the air temperature and wind velocity
is reduced to a slight draught. The water vapour pressure remains unchanged. Under warm/humid conditions, however, it is implicitly
related to a relative humidity of 50%. Clothing is adapted in order to achieve thermal comfort. If this is impossible, cold
or heat stress will occur, respectively. The assessment of thermal perception by means of PT is based on Fanger’s Predicted
Mean Vote (PMV) together with additional model extensions taking account of stronger deviations from thermal neutrality. This
is performed using a parameterisation based on a two-node model. In the cold, it allows the mean skin temperature to drop
below the comfort value. In the heat, it assesses additionally the enthalpy of sweat-moistened skin and of wet clothes. PT
has the advantages of being self-explanatory due to its deviation from air temperature and being—via PMV—directly linked to
a thermo-physiologically-based scale of thermal perception that is widely used and has stood the test of time. This paper
explains in detail the basic equations of the human heat budget and the coefficients of the parameterisations. 相似文献
83.
Teulé F Addison B Cooper AR Ayon J Henning RW Benmore CJ Holland GP Yarger JL Lewis RV 《Biopolymers》2012,97(6):418-431
The two Flag/MaSp 2 silk proteins produced recombinantly were based on the basic consensus repeat of the dragline silk spidroin 2 protein (MaSp 2) from the Nephila clavipes orb weaving spider. However, the proline-containing pentapeptides juxtaposed to the polyalanine segments resembled those found in the flagelliform silk protein (Flag) composing the web spiral: (GPGGX(1) GPGGX(2))(2) with X(1) /X(2) = A/A or Y/S. Fibers were formed from protein films in aqueous solutions or extruded from resolubilized protein dopes in organic conditions when the Flag motif was (GPGGX(1) GPGGX(2))(2) with X(1) /X(2) = Y/S or A/A, respectively. Post-fiber processing involved similar drawing ratios (2-2.5×) before or after water-treatment. Structural (ssNMR and XRD) and morphological (SEM) changes in the fibers were compared to the mechanical properties of the fibers at each step. Nuclear magnetic resonance indicated that the fraction of β-sheet nanocrystals in the polyalanine regions formed upon extrusion, increased during stretching, and was maximized after water-treatment. X-ray diffraction showed that nanocrystallite orientation parallel to the fiber axis increased the ultimate strength and initial stiffness of the fibers. Water furthered nanocrystal orientation and three-dimensional growth while plasticizing the amorphous regions, thus producing tougher fibers due to increased extensibility. These fibers were highly hygroscopic and had similar internal network organization, thus similar range of mechanical properties that depended on their diameters. The overall structure of the consensus repeat of the silk-like protein dictated the mechanical properties of the fibers while protein molecular weight limited these same properties. Subtle structural motif re-design impacted protein self-assembly mechanisms and requirements for fiber formation. 相似文献
84.
85.
86.
Staats CC Junges A Fitarelli M Furlaneto MC Vainstein MH Schrank A 《Applied microbiology and biotechnology》2007,76(4):945-950
The list of fungal species with known complete genome and/or expressed sequence tag collections is extending rapidly during
the last couple of years. Postgenomic gene function assignment is an obvious follow-up and depends on methodologies to test
gene function in vivo. One of such methods is the generation of null mutants via homologous recombination at the wild–type
loci by using inactivation cassettes. In this paper, the ability of Agrobacterium tumefaciens to genetically transform filamentous fungi was exploited to drive homologous recombination at the trp1 locus of the enthomopathogenic fungus Metarhizium anisopliae. The trp1 disruptants exhibited a clearly distinguishable phenotype from wild-type cells and were recovered with high efficiency of
homologous recombination (22%). The complementation of such mutants with the wild-type gene generates only transformants with
homologous integration. 相似文献
87.
Henning Seismann Simon Blank Liliana Cifuentes Ingke Braren Reinhard Bredehorst Thomas Grunwald Markus Ollert Edzard Spillner 《Clinical and molecular allergy : CMA》2010,8(1):1-8
Background
Eosinophils are involved in various inflammatory processes including allergic inflammation during which angiogenesis has been documented. Angiogenesis is most likely connected to the hypoxia which characterizes inflamed tissues. Eosinophils produce VEGF and are pro-angiogenic. However, to the best of our knowledge no study has been performed to verify the existence of a direct link between eosinophils, hypoxia and angiogenesis in allergic inflammation.Objective
To characterize eosinophil function and angiogenic potential under hypoxic conditions.Methods
Human peripheral blood eosinophils were cultured in normoxic or hypoxic conditions with or without cytokines. Viability and apoptosis were assessed by Annexin V/PI staining. Anti- or pro-apoptotic protein levels, HIF-1α levels and MAPK phosphorylation were analyzed by immunoblot analysis. Angiogenic mediator release was evaluated by ELISA.Results
Hypoxic eosinophils were more viable than normoxic ones after up to three days. In addition in hypoxia, anti-apoptotic Bcl-XL protein levels increased more than pro-apoptotic Bax levels. Hypoxia increased VEGF and IL-8 release. In hypoxic eosinophils high levels of HIF-1α were observed, particularly in the presence of GM-CSF. MAPK, particularly ERK1/2 inhibitors, decreased hypoxia-mediated VEGF release and HIF-1α expression.Conclusion
Eosinophils respond to hypoxia by up-regulation of survival and of some of their pro-angiogenic functions indicating a correlation between eosinophilic inflammation and angiogenesis. 相似文献88.
89.
Stem-like cells in human hepatoblastoma. 总被引:9,自引:0,他引:9
Henning C Fiegel Sylvia Glüer Beate Roth Johannes Rischewski Dietrich von Schweinitz Benno Ure Wolfgang Lambrecht Dietrich Kluth 《The journal of histochemistry and cytochemistry》2004,52(11):1495-1501
Hepatoblastoma is a pediatric liver tumor with epithelial components resembling embryonal and fetal liver cells. The existence of teratoid hepatoblastoma suggests the presence of stem cells in hepatoblastoma. The aim of this study was to analyze the expression of stem cell markers in hepatoblastomas. We studied specimens from 10 hepatoblastomas. Five of the hepatoblastomas were of epithelial and five of mixed type. Immunohistochemistry (IHC) for the stem cell markers CD34, Thy1, c-kit, and the hepatic or biliary lineage markers CK-18, OCH, CK-7, and CD56 was performed. Double IHC for stem cell and lineage markers was used to identify putative liver stem cells. The different markers showed distinct distributions on the tumor cells. Cells in atypical ducts were found to express simultaneously stem cell markers and hepatocytic or biliary lineage markers. Other cells in connective tissue showed c-kit expression, but not hepatic or biliary marker expression. The data show the presence of different cell populations bearing stem cell markers in human hepatoblastoma. Ductal cells co-expressing stem cell markers and hepatic lineage markers phenotypically resemble hepatic stem-like cells. These findings support the thesis that stem cells play a role in the histogenesis of hepatoblastoma. 相似文献
90.
Species in the Laxa and Grandia groups of the genus Panicum are adapted to low, wet areas of tropical and subtropical America. Panicum milioides is a species with C3 photosynthesis and low apparent photorespiration and has been classified as a C3/C4 intermediate. Other species in the Laxa group are C3 with normal photorespiration. Panicum prionitis is a C4 species in the Grandia group. Since P. milioides has some leaf characteristics intermediate to C3 and C4 species, its photosynthetic response to irradiance and temperature was compared to the closely related C3 species, P. laxum and P. boliviense and to P. prionitis. The response of apparent photosynthesis to irradiance and temperature was similar to that of P. laxum and P. boliviense, with saturation at a photosynthetic photo flux density of about 1 mmol m-2 s-1 at 30°C and temperature optimum near 30°C. In contrast, P. prionitis showed no light saturation up to 2 mmol m-2 s-1 and an optimum temperature near 40°C. P. milioides exhibited low CO2 loss into CO2-free air in the light and this loss was nearly insensitive to temperature. Loss of CO2 in the light in the C3 species, P. laxum and P. boliviense, was several-fold higher than in P. milioides and increased 2- to 5-fold with increases in temperature from 10 to 40°C. The level of dark respiration and its response to temperature were similar in all four Panicum species examined. It is concluded that the low apparent photorespiration in P. milioides does not influence its response of apparent photosynthesis to irradiance and temperature in comparison to closely related C3 Panicum species.Abbreviations AP
apparent photosynthesis
- I
CO2 compensation point
- gl
leaf conductance; gm, mesophyll conductance
- PPFD
photosynthetic photon flux density
- PR
apparent photorespiration rate
- RuBPC
sibulose bisphosphate carboxylase 相似文献