376 research outputs found
SHELF-LIFE OF HALAL FRESH SLICED BEEF AND MINCED MEAT
Microbiological and chemical-physical characterization of Halal beef fresh and minced meat, vacuum-packaged and stored at +2°C and +8°C, were examined, at 0, 7, 14 and 21 days, to evaluate the shelf-life. Lactic Acid Bacteria and Coliforms were higher in samples stored at +8 °C, particularly in minced meat. Pseudomonas were the most prevalent flora in all the products, and the contamination level, above 4 log10 cfu/g, were reached at 7 days in all the samples and was maintained during the study. The shelf-life can be extended reducing the storage temperature (< +2°C), and improving the packaging conditions
The Photon Dispersion as an Indicator for New Physics ?
We first comment on the search for a deviation from the linear photon
dispersion relation, in particular based on cosmic photons from Gamma Ray
Bursts. Then we consider the non-commutative space as a theoretical concept
that could lead to such a deviation, which would be a manifestation of Lorentz
Invariance Violation. In particular we review a numerical study of pure U(1)
gauge theory in a 4d non-commutative space. Starting from a finite lattice, we
explore the phase diagram and the extrapolation to the continuum and infinite
volume. These simultaneous limits - taken at fixed non-commutativity - lead to
a phase of broken Poincare symmetry, where the photon appears to be IR stable,
despite a negative IR divergence to one loop.Comment: 8 pages, 4 figures, talk presented at the VI International Workshop
on the Dark Side of the Universe, Leon (Mexico), June 1-6, 2010. References
adde
Factor VIII:C concentrate purified from plasma using monoclonal antibodies: human studies
Conventional clotting factor concentrates have, until recently, been of intermediate purity, containing less than 1% of the coagulation factor, and greater than 99% extraneous plasma proteins such as fibrinogen, fibronectin, gamma globulins, and traces of many others. We report here the results of a new factor VIII concentrate that is purified from human plasma using a mouse monoclonal antibody to factor VIII:vWF in an affinity chromatography system. The resultant concentrate has an activity of between 3,000 and 5,000 U/mg protein before albumin is added as a stabilizer. Seven patients with severe hemophilia A and no inhibitor who were positive for antibody to human immunodeficiency virus (HIV) have been treated solely with this concentrate for over 24 months. Factor usage in these patients has ranged from 611 U/kg/yr to 2,022 U/kg/yr. These patients have infused approximately once per week on the average, most often for joint hemorrhages. The efficacy of the concentrate is excellent. No allergic reactions have occurred and no factor VIII antibodies have developed. In these seven patients mean CD4 counts stabilized (856 +/- 619 at screen v 778 +/- 686 at 24 months) and there was reversal of skin test anergy. In a comparison group on conventional intermediate purity concentrate chosen retrospectively decreases in mean CD4 cell counts similarly did not occur. However, the number of the comparison patients who were anergic increased over the course of the study. These observations indicate the possibility that more highly purified concentrates may stabilize immune function in HIV seropositive patients
Improving the prediction of environmental fate of engineered nanomaterials by fractal modelling
A critical analysis of the available engineered nanomaterials (ENMs) environmental fate modelling approaches indicates that existing tools do not satisfactorily account for the complexities of nanoscale phenomena. Fractal modelling (FM) can complement existing kinetic fate models by including more accurate interpretations of shape and structure, density and collision efficiency parameters to better describe homo- and heteroaggregation. Pathways to including hierarchical symmetry concepts and a route to establishing a structural classification of nanomaterials based on FM are proposed
Inducible Nitric Oxide Synthase Provides Protection Against Injury-Induced Thrombosis in Female Mice
Nitric oxide (NO) is an important vasoactive molecule produced by three NO synthase (NOS) enzymes: neuronal (nNOS), inducible (iNOS) and endothelial NOS (eNOS). While eNOS contributes to blood vessel dilation that is generally thought to protect against the development of hypertension, iNOS has been primarily implicated as a disease-promoting isoform leading to protein-bound 3-nitrotyrosine formation in aortic lesions and select organs during atherogenesis. Despite this, iNOS may also play a physiological role, via the modulation of cyclooxygenase and thromboregulatory eicosanoid production. Herein, we examined the role of iNOS in a murine model of thrombosis. Blood flow was measured in carotid arteries of male and female wild-type (WT) and iNOS-deficient mice following ferric chloride-induced thrombosis. Female WT mice were less susceptible to thrombotic occlusion than male counterparts, but this protection was lost upon iNOS deletion. In contrast, male mice (with and without iNOS deletion) were equally susceptible to thrombosis. The protective effect that iNOS affords female WT mice was not associated with a change in the balance of thromboxane A2 (TxA2) and antithrombotic prostacyclin (PGI2). Our findings, however, suggest that iNOS generates a protective source of NO in female WT mice that attenuates the effects of vascular injury. Thus, although iNOS is likely detrimental during atherogenesis, physiological iNOS levels may play a protective role in preventing thrombotic occlusion, a phenomenon that may be enhanced in female mice
Antioxidants Condition Pleiotropic Vascular Responses to Exogenous H2O2: Role of Modulation of Vascular TP Receptors and the Heme Oxygenase System
Aims: Hydrogen peroxide (H(2)O(2)), a nonradical oxidant, is employed to ascertain the role of redox mechanisms in regulation of vascular tone. Where both dilation and constriction have been reported, we examined the hypothesis that the ability of H(2)O(2) to effect vasoconstriction or dilation is conditioned by redox mechanisms and may be modulated by antioxidants.
Results: Exogenous H(2)O(2) (0.1-10.0 μM), dose-dependently reduced the internal diameter of rat renal interlobular and 3rd-order mesenteric arteries (p\u3c0.05). This response was obliterated in arteries pretreated with antioxidants, including tempol, pegylated superoxide dismutase (PEG-SOD), butylated hydroxytoluene (BHT), and biliverdin (BV). However, as opposed to tempol or PEG-SOD, BHT & BV, antioxidants targeting radicals downstream of H(2)O(2), also uncovered vasodilation.
Innovations: Redox-dependent vasoconstriction to H(2)O(2) was blocked by inhibitors of cyclooxygenase (COX) (indomethacin-10 μM), thromboxane (TP) synthase (CGS13080-10 μM), and TP receptor antagonist (SQ29548-1 μM). However, H(2)O(2) did not increase vascular thromboxane B(2) release; instead, it sensitized the vasculature to a TP agonist, U46619, an effect reversed by PEG-SOD. Antioxidant-conditioned dilatory response to H(2)O(2) was accompanied by enhanced vascular heme oxygenase (HO)-dependent carbon monoxide generation and was abolished by HO inhibitors or by HO-1 & 2 antisense oligodeoxynucleotides treatment of SD rats.
Conclusions: These results demonstrate that H(2)O(2) has antioxidant-modifiable pleiotropic vascular effects, where constriction and dilation are brought about in the same vascular segment. H(2)O(2)-induced oxidative stress increases vascular TP sensitivity and predisposes these arterial segments to constrictor prostanoids. Conversely, vasodilation is reliant upon HO-derived products whose synthesis is stimulated only in the presence of antioxidants targeting radicals downstream of H(2)O(2)
Endoplasmic reticulum stress pathway involvement in local and remote myocardial ischemic conditioning.
Remote ischemic perconditioning (RIPer) and local ischemic postconditioning (IPost) are promising methods to decrease ischemia-reperfusion injury. We tested whether these two methods were effective in reducing infarct size through activation of endoplasmic reticulum (ER) stress response, a potential survival pathway. Rats exposed to myocardial ischemia-reperfusion were allocated to one of six groups: control, no intervention at myocardial reperfusion; IPost, three cycles of 10-s coronary artery occlusion followed by 10-s reperfusion applied at the onset of myocardial reperfusion; RIPer, 10-min limb ischemia followed by 10-min reperfusion initiated during coronary artery occlusion; control + 4-PBA, injection of ER stress inhibitor 4-phenylbutyrate (4-PBA) 1 h before coronary occlusion; IPost + 4-PBA; and RIPer + 4-PBA. Infarct size was significantly reduced in IPost and RIPer groups (33.32% ± 3.65% and 21.86% ± 3.98%, respectively) compared with the control group (54.86% ± 6.01%, P < 0.05). Western blot analysis of GRP78 (glucose-regulated protein) level and cleaved activating transcription factor 6, two ER stress markers, demonstrated an enhancement of ER stress response in IPost group but not in RIPer group at 15-min reperfusion. Furthermore, 4-PBA abolished cardioprotection induced by IPost (infarct size 53.75 ± 3.49 vs. 33.32 ± 3.65%, P < 0.05) but not by RIPer (28.80 ± 10.45% vs. 21.86 ± 3.98%, not statistically significant). GRP78 and cleaved activating transcription factor 6 levels were no longer increased in IPost group after 4-PBA. These findings point to a role for ER stress response in cardioprotection against reperfusion injury in IPost but not RIPer, suggesting differences in cardioprotective mechanisms between local and remote conditioning
The Synthetic Pentasaccharide Fondaparinux Attenuates Myocardial Ischemia-Reperfusion Injury in Rats Via STAT-3
Acute myocardial infarction is a leading cause of mortality and morbidity worldwide. Although essential for successful recovery, myocardium reperfusion is associated with reperfusion injury. Two major cell survival signaling cascades are known to be protective against ischemia-reperfusion (I/R) injury: the reperfusion injury salvage kinase, including Akt, extracellular signal–regulated kinase 1/2, and the downstream target GSK-3β, and the survivor activating factor enhancement, which involves STAT-3. Pharmacologic inhibition of factor Xa has been shown to attenuate I/R injury, but the cellular mechanism is poorly understood. Our aim was to determine the role of whole blood in fondaparinux (FDX)-induced cardioprotection and the involvement of reperfusion injury salvage kinase and survivor activating factor enhancement pathways. We investigated FDX ability to prevent in vivo I/R injury using a transient coronary ligation rat model and ex vivo using a model of crystalloid-perfused isolated rat heart. In both models, infarct size was assessed after 120 min of reperfusion. Myocardial tissues were collected after 15 and 30 min of reperfusion for Western blot analysis. In vivo, FDX decreased infarct size by 29% and induced significant STAT-3 and GSK-3β phosphorylation in comparison to controls. Adding AG490, an inhibitor of JAK/STAT pathway, before I/R, prevented STAT-3 phosphorylation and abolished FDX-induced cardioprotection. On the contrary, FDX did not have an effect on infarct size or hemodynamic parameters in the isolated-heart model. Fondaparinux decreased I/R injury in vivo, but not in a crystalloid-perfused isolated heart. Under our experimental conditions, FDX required whole blood to be protective, and this beneficial effect was mediated through STAT-3 phosphorylation
Massive Charged Scalar Quasinormal Modes of Reissner-N\"ordstrom Black Hole Surrounded by Quintessence
We evaluate the complex frequencies of the normal modes for the massive
charged scalar field perturbations around a Reissner-N\"ordstrom black hole
surrounded by a static and spherically symmetric quintessence using third order
WKB approximation approach. Due to the presence of quintessence, quasinormal
frequencies damp more slowly. We studied the variation of quasinormal
frequencies with charge of the black bole, mass and charge of perturbating
scalar field and the quintessential state parameter.Comment: 9 pages, 9 figures and one tabl
Grouping of nanomaterials to read-across hazard endpoints: a review
The use of non-testing strategies like read-across in the hazard assessment of chemicals and nanomaterials (NMs) is deemed essential to perform the safety assessment of all NMs in due time and at lower costs. The identification of physicochemical (PC) properties affecting the hazard potential of NMs is crucial, as it could enable to predict impacts from similar NMs and outcomes of similar assays, reducing the need for experimental (and in particular animal) testing. This manuscript presents a review of approaches and available case studies on the grouping of NMs to read-across hazard endpoints. We include in this review grouping frameworks aimed at identifying hazard classes depending on PC properties, hazard classification modules in control banding (CB) approaches, and computational methods that can be used for grouping for read-across. The existing frameworks and case studies are systematically reported. Relevant nanospecific PC properties taken into account in the reviewed frameworks to support grouping are shape and surface properties (surface chemistry or reactivity) and hazard classes are identified on the basis of biopersistence, morphology, reactivity, and solubility.JRC.F.3-Chemicals Safety and Alternative Method
- …