4,060 research outputs found

    Different cell disruption methods for astaxanthin recovery by Phaffia rhodozyma

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    Astaxanthin (3,3'-dihydroxy-b,b'-carotene-4,4'-dione) is carotenoid of high market value whose demand has increased in such fields as aquaculture, pharmaceutical supplements and natural coloring. Cell disruption is the first step for isolating intracellular materials and it depends on the cell wall permeability. In order to maximize the  recovery of astaxanthin from Phaffia rhodozyma NRRL-Y17268, drying and freeze pretreatments were tested by different cell disruption methods: abrasion with celite, glass pearls in vortex agitator, ultrasonic waves, sodium  carbonate (Na2CO3) and dimethyl sulfoxide (DMSO). The method with Na2CO3 was not effective; meanwhile, the agitator with glass pearls, the abrasion with celite and the ultrasonic waves were found as promising for future  studies. As a result, the DMSO in freeze-dried biomass with 4 process cycles and biomass/DMSO relation of 0.025 g/ml was found to be the most efficient for analytical determination, increasing about up to 25 times the astaxanthin recovery.Key words: Carotenoids, yeast, chemical disruption, dimethyl sulfoxide

    Polyvalent horse F(Ab`)2 snake antivenom: Development of process to produce polyvalent horse F(Ab`)2 antibodies anti-african snake venom

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    A method to obtain polyvalent anti-Bitis and polyvalent-anti-Naja antibodies was developed by immunizing horses with B. arietans, B. nasicornis, B. rhinoceros, N. melanoleuca and N. mossambicacrude venoms. Antibody production was followed by the ELISA method during the immunization procedure. Once the desired anti-venom antibody titers were attained, horses were bled and the immunoglobulins were separated from the sera by (NH4)2SO4 precipitation, cleaved with pepsin and filtered through a 30 kDa ultrafiltration membrane. F(ab´)2 fragments were further purified by Q-Fast Flow chromatography, concentrated by molecular ultrafiltration and sterilized by filtration through 0.22 m membranes. The resulting F(ab´)2 preparations were rich in intact L and in pieces of H IgG(T) chains, as demonstrated by electrophoresis and Western blot and exhibited high antibody titers, as assayed by the ELISA method. In addition, the preparations possess a significant capacity to neutralize the lethality of venoms, as estimated by ED50 determination in mouse assay and are free of toxic substances, pyrogen and bacterial or fungal contaminations

    Mesenchymal stromal cells induce regulatory T cells via epigenetic conversion of human conventional CD4 T cells in vitro.

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    Regulatory T cells (Treg) play a critical role in immune tolerance. The scarcity of Treg therapy clinical trials in humans has been largely due to the difficulty in obtaining sufficient Treg numbers. We performed a preclinical investigation on the potential of mesenchymal stromal cells (MSCs) to expand Treg in vitro to support future clinical trials. Human peripheral blood mononuclear cells from healthy donors were cocultured with allogeneic bone marrow-derived MSCs expanded under xenogeneic-free conditions. Our data show an increase in the counts and frequency of CD4+ CD25high Foxp3+ CD127low Treg cells (4- and 6-fold, respectively) after a 14-day coculture. However, natural Treg do not proliferate in coculture with MSCs. When purified conventional CD4 T cells (Tcon) are cocultured with MSCs, only cells that acquire a Treg-like phenotype proliferate. These MSC-induced Treg-like cells also resemble Treg functionally, since they suppress autologous Tcon proliferation. Importantly, the DNA methylation profile of MSC-induced Treg-like cells more closely resembles that of natural Treg than of Tcon, indicating that this population is stable. The expression of PD-1 is higher in Treg-like cells than in Tcon, whereas the frequency of PDL-1 increases in MSCs after coculture. TGF-β levels are also significantly increased MSC cocultures. Overall, our data suggest that Treg enrichment by MSCs results from Tcon conversion into Treg-like cells, rather than to expansion of natural Treg, possibly through mechanisms involving TGF-β and/or PD-1/PDL-1 expression. This MSC-induced Treg population closely resembles natural Treg in terms of phenotype, suppressive ability, and methylation profile

    The Underestimation Of Egocentric Distance: Evidence From Frontal Matching Tasks

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    There is controversy over the existence, nature, and cause of error in egocentric distance judgments. One proposal is that the systematic biases often found in explicit judgments of egocentric distance along the ground may be related to recently observed biases in the perceived declination of gaze (Durgin & Li, Attention, Perception, & Psychophysics, in press), To measure perceived egocentric distance nonverbally, observers in a field were asked to position themselves so that their distance from one of two experimenters was equal to the frontal distance between the experimenters. Observers placed themselves too far away, consistent with egocentric distance underestimation. A similar experiment was conducted with vertical frontal extents. Both experiments were replicated in panoramic virtual reality. Perceived egocentric distance was quantitatively consistent with angular bias in perceived gaze declination (1.5 gain). Finally, an exocentric distance-matching task was contrasted with a variant of the egocentric matching task. The egocentric matching data approximate a constant compression of perceived egocentric distance with a power function exponent of nearly 1; exocentric matches had an exponent of about 0.67. The divergent pattern between egocentric and exocentric matches suggests that they depend on different visual cues

    Aortic valve replacement with different types of prosthesis. Are there differences in the outcomes during hospital phase?

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    Objective: To analyze intraoperative data and possible differences in clinical evolution during postoperative hospital phase for aortic valve replacement surgery using different types of prosthesis. Methods: Analysis of 60 patients divided into three groups. Valve replacement with bioprosthesis (20), mechanical prosthesis (20) and homologous valve (20). The mean age was 51.1, 60% were male and 40% female patients; 86.7% were in NYHA II or III; 63.3% presented arterial hypertension and 18.3% had diabetes. Aetiology of valve disease was degenerative for 39%, rheumatic for 36% and endocardits for 15%. Results: The hospital mortality was 5%; there were no differences in the incidence of septical or cardiogenic intensive care, neither for total time in intensive care and mechanical ventilation. However, there was statistical differences as regards the cardiopulmonary bypass total time (P=0.02) and the aortic clamping time (P<0.0001) unfavorable to homograft valve group. The ward admission time was greater for mechanical valve group (P=0.05) as well as for total admission time, but without statistical significance. It was observed that patients with preoperative hematocrit smaller than 38.1% used 2.73 units of blood components, and with postoperative hematocrit smaller than 32% used 1,79 units of blood components. Echocardiography control showed minimal evolutional differences. Conclusion: The use of different types of prosthesis for this study does not cause differences in the results of postoperative hospital phase. The use of homograft valve is a feasible option with good clinical applicability23453454

    Guidelines for the recording and evaluation of pharmaco-EEG data in man: the International Pharmaco-EEG Society (IPEG)

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    The International Pharmaco-EEG Society (IPEG) presents updated guidelines summarising the requirements for the recording and computerised evaluation of pharmaco-EEG data in man. Since the publication of the first pharmaco-EEG guidelines in 1982, technical and data processing methods have advanced steadily, thus enhancing data quality and expanding the palette of tools available to investigate the action of drugs on the central nervous system (CNS), determine the pharmacokinetic and pharmacodynamic properties of novel therapeutics and evaluate the CNS penetration or toxicity of compounds. However, a review of the literature reveals inconsistent operating procedures from one study to another. While this fact does not invalidate results per se, the lack of standardisation constitutes a regrettable shortcoming, especially in the context of drug development programmes. Moreover, this shortcoming hampers reliable comparisons between outcomes of studies from different laboratories and hence also prevents pooling of data which is a requirement for sufficiently powering the validation of novel analytical algorithms and EEG-based biomarkers. The present updated guidelines reflect the consensus of a global panel of EEG experts and are intended to assist investigators using pharmaco-EEG in clinical research, by providing clear and concise recommendations and thereby enabling standardisation of methodology and facilitating comparability of data across laboratories

    Tic disorders and the premonitory urge

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    The aims of this study were to examine a non-English (Hebrew) version of a scale that measures the premonitory urge in children suffering from tic disorder, as well as examine the correlations of the urge with demographic and clinical aspects of Tourette Syndrome. Forty children and adolescents, suffering from tics participated in this study. They were assessed with the Premonitory Urge for Tics Scale (PUTS); the Yale Global Tic Severity Scale (YGTSS); the Childhood Version of the Yale Brown Obsessive Compulsive Scale (CYBOCS); the ADHD Rating Scale IV (Conners) Scale; the Screen for Child Anxiety Related Emotional Disorders (SCARED); and the Child Depression Inventory (CDI). The mean PUTS score was 20.15 (SD = 5.89). For the entire sample the PUTS was found to be internally consistent at a = 0.79. Youths older than 10 years had higher consistency (a = 0.83) than youths younger than 10 (a = 0.69). Premonitory urge was not correlated with tic severity in the entire sample. In youths older than 10, as opposed to youths younger than 10, premonitory urge did correlate with obsessions, compulsions and depression, but not with anxiety or with ADHD. The premonitory urge can be measured reliably and the PUTS is a useful instrument for measuring this important phenomena. Premonitory urges seems to be related to obsessions, compulsions, and depression in older children and this may have implications for the developmental psychopatholgy of these symptoms
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