998 resultados para Tissue Temperature
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BACKGROUND/AIM: Both steatosis and insulin resistance have been linked to accelerated fibrosis in chronic hepatitis C. Connective tissue growth factor (CTGF) plays a major role in extracellular matrix production in fibrotic disorders including cirrhosis, and its expression is stimulated in vitro by insulin and glucose. We hypothesized that CTGF may link steatosis, insulin resistance and fibrosis. METHODS: We included 153 chronic hepatitis C patients enrolled in the Swiss Hepatitis C Cohort Study and for whom a liver biopsy and plasma samples were available. CTGF expression was assessed quantitatively by immunohistochemistry. In 94 patients (57 with genotypes non-3), plasma levels of glucose, insulin and leptin were also measured. CTGF synthesis was investigated by immunoblotting on LX-2 stellate cells. RESULTS: Connective tissue growth factor expression was higher in patients with steatosis (P=0.039) and in patients with fibrosis (P=0.008) than those without these features. CTGF levels were neither associated with insulinaemia or with glycaemia, nor with inflammation. By multiple regression analysis, CTGF levels were independently associated with steatosis, a past history of alcohol abuse, plasma leptin and HCV RNA levels; when only patients with genotypes non-3 were considered, CTGF levels were independently associated with a past history of alcohol abuse, plasma leptin levels and steatosis. Leptin stimulated CTGF synthesis in LX-2 cells. CONCLUSIONS: In patients with chronic hepatitis C and steatosis, CTGF may promote fibrosis independently of inflammation. CTGF may link steatosis and fibrosis via increased leptin levels.
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Having determined in a phase I study the maximum tolerated dose of high-dose ifosfamide combined with high-dose doxorubicin, we now report the long-term results of a phase II trial in advanced soft-tissue sarcomas. Forty-six patients with locally advanced or metastatic soft-tissue sarcomas were included, with age <60 years and all except one in good performance status (0 or 1). The chemotherapy treatment consisted of ifosfamide 10 g m(-2) (continuous infusion for 5 days), doxorubicin 30 mg m(-2) day(-1) x 3 (total dose 90 mg m(-2)), mesna and granulocyte-colony stimulating factor. Cycles were repeated every 21 days. A median of 4 (1-6) cycles per patient was administered. Twenty-two patients responded to therapy, including three complete responders and 19 partial responders for an overall response rate of 48% (95% CI: 33-63%). The response rate was not different between localised and metastatic diseases or between histological types, but was higher in grade 3 tumours. Median overall survival was 19 months. Salvage therapies (surgery and/or radiotherapy) were performed in 43% of patients and found to be the most significant predictor for favourable survival (exploratory multivariate analysis). Haematological toxicity was severe, including grade > or =3 neutropenia in 59%, thrombopenia in 39% and anaemia in 27% of cycles. Three patients experienced grade 3 neurotoxicity and one patient died of septic shock. This high-dose regimen is toxic but nonetheless feasible in multicentre settings in non elderly patients with good performance status. A high response rate was obtained. Prolonged survival was mainly a function of salvage therapies.
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Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily that can be activated by various xenobiotics and natural fatty acids. These transcription factors primarily regulate genes involved in lipid metabolism and also play a role in adipocyte differentiation. We present the expression patterns of the PPAR subtypes in the adult rat, determined by in situ hybridization using specific probes for PPAR-alpha, -beta and -gamma, and by immunohistochemistry using a polyclonal antibody that recognizes the three rat PPAR subtypes. In numerous cell types from either ectodermal, mesodermal, or endodermal origin, PPARs are coexpressed, with relative levels varying between them from one cell type to the other. PPAR-alpha is highly expressed in hepatocytes, cardiomyocytes, enterocytes, and the proximal tubule cells of kidney. PPAR-beta is expressed ubiquitously and often at higher levels than PPAR-alpha and -gamma. PPAR-gamma is expressed predominantly in adipose tissue and the immune system. Our results suggest new potential directions to investigate the functions of the different PPAR subtypes.
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The distribution of the uncoupling protein (UCP) in brown adipocyte mitochondria of the hibernant Muscardinus avellanarius was obtained by ultrastructural immunocytochemistry. In both cryosections and sections of Lowicryl-embedded material UCP was localized in the mitochondrial cristae of brown adipocytes, but not in liver mitochondria. It should now be possible to easily identify the morphology of cells committed to BAT differentiation in the tissue as well as in cell culture.
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Entamoeba histolytica, the protozoan parasite causing human amoebisis, has recently been found to comprise two genetically distinct forms, potentially pathogenic and constitutively nonpathogenic ones. Host tissue destruction by pathogenic forms is belived to result from cell functions mediaed by a lectin-type adherence receptor, a pore-forming peptide involved in host cell lysis, and abundant expression of cysteine proteinase(s). Isolation and molecular cloning of these amoeba products have provided the tools for structural analyses and manipulations of cell functions including comparisons between pathogenic and nonpathogenic forms.
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Aside from ethical considerations, the primary requirement for usage of human tissues in basic or translational research is the thorough characterization of tissues. The second, but equally essential, requirement is that tissues be collected, processed, annotated, and preserved in optimal conditions. These requirements put the pathologist at the center of tissue banking activities and of research aimed at discovering new biomarkers. Pathologists not only provide information identifying the specimen but also make decisions on what materials should be biobanked, on the preservation conditions, and on the timeline of events that precede preservation and storage. This central position calls for increased recognition of the role of the pathologist by the biomolecular community and places new demands on the pathologist's workload and scope of scientific activities. These questions were addressed by an Expert Group Meeting of the European Biological and Biomolecular Research Infrastructure (BBMRI). While detailed recommendations are published elsewhere (Bevilacqua et al., Virchows Archivs, 2010, in press), this article outlines the strategic and technological issues identified by the Expert Group and identifies ways forward for better integration of pathology in the current thrust for development of biomarker-based "personalized medicine.
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The effect of temperature (20 degrees-35 degrees C) on different stages of Romanomermis iyengari was studied. In embryonic development, the single-cell stage eggs developed into mature eggs in 4.5-6.5 days at 25-35 degrees C but, required 9.5 days at 20 degrees C. Complete hatching occurred in 7 and 9 days after egg-laying at 35 and 30 degrees C, respectively. At 25 and 20 degrees C, 85-96 of the eggs did not hatch even by 30th day. Loss of infectivity and death of the preparasites occurred faster at higher temperatures. The 50 survival durations of preparasites at 20 and 35 degrees C were 105.8 and 10.6 hr respectively. They retained 50 infectivity up to 69.7 and 30.3 hr. The duration of the parasitic phase increased as temperature decreased. Low temperature favoured production of a higher proportion of females which were also larger in size. The maximum time taken for the juveniles to become adults was 14 days at 20 degrees C and the minimum was 9 days at 35 degrees C. Oviposition began earlier at higher temperature than at lower temperature. However, its fecundic period was shorter at 20 degrees C than at 35 degrees C indicating enhanced rate of oviposition at 20 degrees C. Fecundity was adversely affected at 20 degrees C and 35 degrees C. It is shown that the temperature range of 25 degrees-30 degrees C favours optimum development of R. iyengari.
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BACKGROUND: Individually, randomised trials have not shown conclusively whether adjuvant chemotherapy benefits adult patients with localised resectable soft-tissue sarcoma.METHODS: A quantitative meta-analysis of updated data from individual patients from all available randomised trials was carried out to assess whether adjuvant chemotherapy improves overall survival, recurrence-free survival, and local and distant recurrence-free intervals (RFI) and whether chemotherapy is differentially effective in patients defined by age, sex, disease status at randomisation, disease site, histology, grade, tumour size, extent of resection, and use of radiotherapy.FINDINGS: 1568 patients from 14 trials of doxorubicin-based adjuvant chemotherapy were included (median follow-up 9.4 years). Hazard ratios of 0.73 (95% CI 0.56-0.94, p = 0.016) for local RFI, 0.70 (0.57-0.85, p = 0.0003) for distant RFI, and 0.75 (0.64-0.87, p = 0.0001) for overall recurrence-free survival, correspond to absolute benefits from adjuvant chemotherapy of 6% (95% CI 1-10), 10% (5-15), and 10% (5-15), respectively, at 10 years. For overall survival the hazard ratio of 0.89 (0.76-1.03) was not significant (p = 0.12), but represents an absolute benefit of 4% (1-9) at 10 years. These results were not affected by prespecified changes in the groups of patients analysed. There was no consistent evidence that the relative effect of adjuvant chemotherapy differed for any subgroup of patients for any endpoint. However, the best evidence of an effect of adjuvant chemotherapy for survival was seen in patients with sarcomas of the extremities.INTERPRETATION: The meta-analysis provides evidence that adjuvant doxorubicin-based chemotherapy significantly improves the time to local and distant recurrence and overall recurrence-free survival. There is a trend towards improved overall survival.
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The sensitivity of altitudinal and latitudinal tree-line ecotones to climate change, particularly that of temperature, has received much attention. To improve our understanding of the factors affecting tree-line position, we used the spatially explicit dynamic forest model TreeMig. Although well-suited because of its landscape dynamics functions, TreeMig features a parabolic temperature growth response curve, which has recently been questioned. and the species parameters are not specifically calibrated for cold temperatures. Our main goals were to improve the theoretical basis of the temperature growth response curve in the model and develop a method for deriving that curve's parameters from tree-ring data. We replaced the parabola with an asymptotic curve, calibrated for the main species at the subalpine (Swiss Alps: Pinus cembra, Larix decidua, Picea abies) and boreal (Fennoscandia: Pinus sylvestris, Betula pubescens, P. abies) tree-lines. After fitting new parameters, the growth curve matched observed tree-ring widths better. For the subalpine species, the minimum degree-day sum allowing, growth (kDDMin) was lowered by around 100 degree-days; in the case of Larix, the maximum potential ring-width was increased to 5.19 mm. At the boreal tree-line, the kDDMin for P. sylvestris was lowered by 210 degree-days and its maximum ring-width increased to 2.943 mm; for Betula (new in the model) kDDMin was set to 325 degree-days and the maximum ring-width to 2.51 mm; the values from the only boreal sample site for Picea were similar to the subalpine ones, so the same parameters were used. However, adjusting the growth response alone did not improve the model's output concerning species' distributions and their relative importance at tree-line. Minimum winter temperature (MinWiT, mean of the coldest winter month), which controls seedling establishment in TreeMig, proved more important for determining distribution. Picea, P. sylvestris and Betula did not previously have minimum winter temperature limits, so these values were set to the 95th percentile of each species' coldest MinWiT site (respectively -7, -11, -13). In a case study for the Alps, the original and newly calibrated versions of TreeMig were compared with biomass data from the National Forest Inventor), (NFI). Both models gave similar, reasonably realistic results. In conclusion, this method of deriving temperature responses from tree-rings works well. However, regeneration and its underlying factors seem more important for controlling species' distributions than previously thought. More research on regeneration ecology, especially at the upper limit of forests. is needed to improve predictions of tree-line responses to climate change further.
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Measuring tissue oxygenation in vivo is of interest in fundamental biological as well as medical applications. One minimally invasive approach to assess the oxygen partial pressure in tissue (pO2) is to measure the oxygen-dependent luminescence lifetime of molecular probes. The relation between tissue pO2 and the probes' luminescence lifetime is governed by the Stern-Volmer equation. Unfortunately, virtually all oxygen-sensitive probes based on this principle induce some degree of phototoxicity. For that reason, we studied the oxygen sensitivity and phototoxicity of dichlorotris(1, 10-phenanthroline)-ruthenium(II) hydrate [Ru(Phen)] using a dedicated optical fiber-based, time-resolved spectrometer in the chicken embryo chorioallantoic membrane. We demonstrated that, after intravenous injection, Ru(Phen)'s luminescence lifetime presents an easily detectable pO2 dependence at a low drug dose (1 mg∕kg) and low fluence (120 mJ∕cm2 at 470 nm). The phototoxic threshold was found to be at 10 J∕cm2 with the same wavelength and drug dose, i.e., about two orders of magnitude larger than the fluence necessary to perform a pO2 measurement. Finally, an illustrative application of this pO2 measurement approach in a hypoxic tumor environment is presented.
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Chrysomya albiceps specimens were obtained from colonies established with larvae and adults collected at the Federal Rural University in Rio de Janeiro, Seropédica, State of Rio de Janeiro. The larval stage of C. albiceps was allowed to develop in climatic chambers at temperatures of 18, 22, 27 and 32ºC, and the pupal stage was allowed to develop at 22, 27 and 32ºC (60 ± 10% RH and 14 hr photoperiod). The duration and viability of the larval stage of C. albiceps at 18, 22, 27 and 32ºC were 21.30, 10.61, 5.0 and 4.0 days and 76.5, 88.5, 98.5 and 99.5%, respectively, with mean mature larval weights of 45.16, 81.86, 84.35 and 70.53 mg, respectively. Mean duration and viability of the pupal stage at 22, 27 and 32ºC were 9.36, 4.7 and 3.0 days and 93.8, 100 and 100%, respectively. The basal temperature for the larval and pupal stage and for the larval and adult phase were 15.04, 17.39 and 15.38ºC, corresponding to 65.67, 44.15 and 114.23 DD.
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We show here a simplified reverse transcription-polymerase chain reaction (RT-PCR) for identification of dengue type 2 virus. Three dengue type 2 virus strains, isolated from Brazilian patients, and yellow fever vaccine 17DD, as a negative control, were used in this study. C6/36 cells were infected with the virus, and tissue culture fluids were collected after 7 days of infection period. The RT-PCR, a combination of RT and PCR done after a single addition of reagents in a single reaction vessel was carried out following a digestion of virus with 1% Nonidet P-40. The 50ml assay reaction mixture included 50 pmol of a dengue type 2 specific primer pair amplifying a 210 base pair sequence of the envelope protein gene, 0.1 mM of the four deoxynucleoside triphosphates, 7.5U of reverse transcriptase, and 1U of thermostable Taq DNA polymerase. The reagent mixture was incubated for 15 min at 37oC for RT followed by a variable amount of cycles of two-step PCR amplification (92oC for 60 sec, 53oC for 60 sec) with slow temperature increment. The PCR products were subjected to 1.7% agarose gel electrophoresis and visualized with UV light after gel incubation in ethidium bromide solution. DNA bands were observed after 25 and 30 cycles of PCR. Virus amount as low as 102.8 TCID50/ml was detected by RT-PCR. Specific DNA amplification was observed with the three dengue type 2 strains. This assay has advantages compared to other RT-PCRs: it avoids laborious extraction of virus RNA; the combination of RT and PCR reduces assay time, facilitates the performance and reduces risk of contamination; the two-step PCR cycle produces a clear DNA amplification, saves assay time and simplifies the technique
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Multipotent mesenchymal stromal cells (MSCs) are a type of adult stem cells that can be easily isolated from various tissues and expanded in vitro. Many reports on their pluripotency and possible clinical applications have raised hopes and interest in MSCs. In an attempt to unify the terminology and the criteria to label a cell as MSC, in 2006 the International Society for Cellular Therapy (ISCT) proposed a standard set of rules to define the identity of these cells. However, MSCs are still extracted from different tissues, by diverse isolation protocols, are cultured and expanded in different media and conditions. All these variables may have profound effects on the selection of cell types and the composition of heterogeneous subpopulations, on the selective expansion of specific cell populations with totally different potentials and ergo, on the long-term fate of the cells upon in vitro culture. Therefore, specific molecular and cellular markers that identify MSCs subsets as well as standardization of expansion protocols for these cells are urgently needed. Here, we briefly discuss new useful markers and recent data supporting the rapidly emerging concept that many different types of progenitor cells are found in close association with blood vessels. This knowledge may promote the necessary technical improvements required to reduce variability and promote higher efficacy and safety when isolating and expanding these cells for therapeutic use. In the light of the discussed data, particularly the identification of new markers, and advances in the understanding of fundamental MSC biology, we also suggest a revision of the 2006 ISCT criteria.
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OBJECTIVE: Atherosclerosis is a chronic inflammatory disease of major conduit arteries. Similarly, obesity and type 2 diabetes mellitus are associated with accumulation of macrophages in visceral white adipose tissue and pancreatic islets. Our goal was to characterize systemic inflammation in atherosclerosis with hypercholesterolemia, but without obesity. METHODS AND RESULTS: We compared 22-week-old apolipoprotein E knockout (ApoE(-/-)) with wild-type mice kept for 14 weeks on a high cholesterol (1.25%) diet (CD, n=8) and 8-week-old ApoE(-/-) with wild-type mice kept on a normal diet (ND, n=8). Hypercholesterolemic, atherosclerotic ApoE(-/-) mice on CD exhibited increased macrophages and T-cells in plaques and periadventitial adipose tissue that revealed elevated expression of MIP-1alpha, IL-1beta, IL-1 receptor, and IL-6. Mesenteric adipose tissue and pancreatic islets in ApoE(-/-) mice showed increased macrophages. Expression of IL-1beta was enhanced in mesenteric adipose tissue of ApoE(-/-) mice on CD. Furthermore, these mice exhibited steatohepatitis with macrophage and T-cell infiltrations as well as increased MIP-1alpha and IL-1 receptor expression. Blood glucose, insulin and total body weight did not differ between the groups. CONCLUSIONS: In hypercholesterolemic lean ApoE(-/-) mice, inflammation extends beyond atherosclerotic plaques to the periadventitial and visceral adipose tissue, liver, and pancreatic islets without affecting glucose homeostasis.