46 research outputs found

    Indoor Dust as a Source of Virulent Strains of the Agents of Cryptococcosis in the Rio Negro Micro-Region of the Brazilian Amazon.

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    Cryptococcosis, a potentially fatal mycosis in humans, is acquired via exposure to exogenous environmental sources. This study aimed to investigate the frequency, genetic diversity, and virulence of cryptococcal strains isolated from indoor dust in the Rio Negro micro-region of the Brazilian Amazon. A total of 8.9% of the studied houses were positive, recovering nine Cryptococcus neoformans VNI and 16 C. gattii VGII isolates, revealing an endemic pattern in domestic microenvironments. The International Society for Human and Animal Mycology (ISHAM) consensus multilocus sequence typing (MLST) scheme for the C. neoformans/C. gattii species complexes identified two sequence types (STs), ST93 and ST5, amongst C. neoformans isolates and six STs amongst C. gattii isolates, including the Vancouver Island Outbreak ST7 (VGIIa) and ST20 (VGIIb), the Australian ST5, and ST264, ST268 and ST445, being unique to the studied region. Virulence studies in the Galleria mellonella model showed that five C. gattii strains and one C. neoformans strain showed a similar pathogenic potential to the highly virulent Vancouver Island outbreak strain CDR265 (VGIIa). The findings of this study indicate that humans can be exposed to the agents of cryptococcosis via house dust, forming the basis for future studies to analyze the impact of early and continuous exposure to indoor dust on the development of subclinical or clinical infections

    Phytosphingosine-phosphate is a signal for AtMPK6 activation and Arabidopsis response to chilling

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    Long-chain bases (LCBs) are pleiotropic sphingolipidic signals in eukaryotes. We investigated the source and function of phytosphingosine-1-phosphate (PHS-P), a phospho-LCB rapidly and transiently formed in Arabidopsis thaliana on chilling.PHS-P was analysed by thin-layer chromatography following in vivo metabolic radiolabelling. Pharmacological and genetic approaches were used to identify the sphingosine kinase isoforms involved in cold-responsive PHS-P synthesis. Gene expression, mitogen-activated protein kinase activation and growth phenotypes of three LCB kinase mutants (lcbk1, sphk1 and lcbk2) were studied following cold exposure. Chilling provoked the rapid and transient formation of PHS-P in Arabidopsis cultured cells and plantlets. Cold-evoked PHS-P synthesis was reduced by LCB kinase inhibitors and abolished in the LCB kinase lcbk2 mutant, but not in lcbk1 and sphk1 mutants. lcbk2 presented a constitutive AtMPK6 activation at 22°C. AtMPK6 activation was also triggered by PHS-P treatment independently of PHS/PHS-P balance. lcbk2 mutants grew comparably with wild-type plants at 22 and 4°C, but exhibited a higher root growth at 12°C, correlated with an altered expression of the cold-responsive DELLA gene RGL3. Together, our data indicate a function for LCBK2 in planta. Furthermore, they connect PHS-P formation with plant response to cold, expanding the field of LCB signalling in plants

    Implantation Serine Proteinase 1 Exhibits Mixed Substrate Specificity that Silences Signaling via Proteinase-Activated Receptors

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    Implantation S1 family serine proteinases (ISPs) are tryptases involved in embryo hatching and uterine implantation in the mouse. The two different ISP proteins (ISP1 and ISP2) have been detected in both pre- and post-implantation embryo tissue. To date, native ISP obtained from uterus and blastocyst tissues has been isolated only as an active hetero-dimer that exhibits trypsin-like substrate specificity. We hypothesised that in isolation, ISP1 might have a unique substrate specificity that could relate to its role when expressed alone in individual tissues. Thus, we isolated recombinant ISP1 expressed in Pichia pastoris and evaluated its substrate specificity. Using several chromogenic substrates and serine proteinase inhibitors, we demonstrate that ISP1 exhibits trypsin-like substrate specificity, having a preference for lysine over arginine at the P1 position. Phage display peptide mimetics revealed an expanded but mixed substrate specificity of ISP1, including chymotryptic and elastase activity. Based upon targets observed using phage display, we hypothesised that ISP1 might signal to cells by cleaving and activating proteinase-activated receptors (PARs) and therefore assessed PARs 1, 2 and 4 as potential ISP1 targets. We observed that ISP1 silenced enzyme-triggered PAR signaling by receptor-disarming. This PAR-disarming action of ISP1 may be important for embryo development and implantation

    Instrumental Perspectivism: Is AI Machine Learning Technology like NMR Spectroscopy?

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    The question, “Will science remain human?” expresses a worry that deep learning algorithms will replace scientists in making crucial judgments of classification and inference and that something crucial will be lost if that happens.  Ever since the introduction of telescopes and microscopes humans have relied on technologies to “extend” beyond human sensory perception in acquiring scientific knowledge.  In this paper I explore whether the ways in which new learning technologies “extend” beyond human cognitive aspects of science can be treated instrumentally. I will consider the norms for determining the reliability of a detection instrument, nuclear magnetic resonance spectroscopy, in predicting models of protein atomic structure. Do the same norms that apply in that case be used to judge the reliability of Artificial Intelligence deep learning algorithms

    Pubertal high fat diet: effects on mammary cancer development

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    INTRODUCTION: Epidemiological studies linking dietary fat intake and obesity to breast cancer risk have produced inconsistent results. This may be due to the difficulty of dissociating fat intake from obesity, and/or the lack of defined periods of exposure in these studies. The pubertal mammary gland is highly sensitive to cancer-causing agents. We assessed how high fat diet (HFD) affects inflammation, proliferative, and developmental events in the pubertal gland, since dysregulation of these can promote mammary tumorigenesis. To test the effect of HFD initiated during puberty on tumorigenesis, we utilized BALB/c mice, for which HFD neither induces obesity nor metabolic syndrome, allowing dissociation of HFD effects from other conditions associated with HFD. METHODS: Pubertal BALB/c mice were fed a low fat diet (12% kcal fat) or a HFD (60% kcal fat), and subjected to carcinogen 7,12-dimethylbenz[a]anthracene (DMBA)-induced tumorigenesis. RESULTS: HFD elevated mammary gland expression of inflammatory and growth factor genes at 3 and 4 weeks of diet. Receptor activator of nuclear factor kappa-B ligand (RANKL), robustly induced at 4 weeks, has direct mitogenic activity in mammary epithelial cells and, as a potent inducer of NF-κB activity, may induce inflammatory genes. Three weeks of HFD induced a transient influx of eosinophils into the mammary gland, consistent with elevated inflammatory factors. At 10 weeks, prior to the appearance of palpable tumors, there were increased numbers of abnormal mammary epithelial lesions, enhanced cellular proliferation, increased growth factors, chemokines associated with immune-suppressive regulatory T cells, increased vascularization, and elevated M2 macrophages. HFD dramatically reduced tumor latency. Early developing tumors were more proliferative and were associated with increased levels of tumor-related growth factors, including increased plasma levels of HGF in tumor-bearing animals. Early HFD tumors also had increased vascularization, and more intra-tumor and stromal M2 macrophages. CONCLUSIONS: Taken together in this non-obesogenic context, HFD promotion of inflammatory processes, as well as local and systemically increased growth factor expression, are likely responsible for the enhanced tumorigenesis. It is noteworthy that although DMBA mutagenesis is virtually random in its targeting of genes in tumorigenesis, the short latency tumors arising in animals on HFD showed a unique gene expression profile, highlighting the potent overarching influence of HFD

    Methamphetamine-Associated Psychosis

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    Diversity on Adjudicative Administrative Tribunals: An Integrative Conception

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    This thesis applies arguments for greater diversity, and more specifically, racial diversity, on the judiciary to administrative tribunals with an adjudicative function. I draw from both formal arguments, such as institutional legitimacy, and substantive arguments, such as the different perspectives that diversity would provide, to propose an integrative conception of diversity. By relying upon concepts such as structural impartiality, I argue that an integrative conception of diversity more fully reveals the transformative potential of diversity in legal decision-making. This integrative conception is particularly well-suited to the administrative context because it demonstrates how diversity will enhance the values of participation and justification, which are instrumental to the principle of fairness. Through interviews with adjudicators and legal clinic lawyers, I offer a preliminary view of the potential impact that diverse administrative adjudicators could have in practice. Finally, this thesis offers recommendations on how this potential could be further realized.MAS

    Implantation serine proteinase 2 is a monomeric enzyme with mixed serine proteolytic activity and can silence signalling via proteinase activated receptors

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    Implantation serine proteinase 2 (ISP2), a S1 family serine proteinase, is known for its role in the critical processes of embryo hatching and implantation in the mouse uterus. Native implantation serine proteinases (ISPs) are co-expressed and co-exist as heterodimers in uterine and blastocyst tissues. The ISP1-ISP2 enzyme complex shows trypsin-like substrate specificity. In contrast, we found that ISP2, isolated as a 34 kDa monomer from a Pichia pastoris expression system, exhibited a mixed serine proteolytic substrate specificity, as determined by a phage display peptide cleavage approach and verified by the in vitro cleavage of synthetic peptides. Based upon the peptide sequence substrate selectivity, a database search identified many potential ISP2 targets of physiological relevance, including the proteinase activated receptor 2 (PAR2). The in vitro cleavage studies with PAR2-derived peptides confirmed the mixed substrate specificity of ISP2. Treatment of cell lines expressing proteinase-activated receptors (PARs) 1, 2, and 4 with ISP2 prevented receptor activation by either thrombin (PARs 1 and 4) or trypsin (PAR2). The disarming and silencing of PARs by ISP2 may play a role in successful embryo implantation. © 2013 Published by NRC Research Press

    Stereoscopic digital mammography: improved specificity and reduced rate of recall in a prospective clinical trial

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    PURPOSE: To compare stereoscopic digital mammography (DM) with standard DM for the rate of patient recall and the detection of cancer in a screening population at elevated risk for breast cancer. MATERIALS AND METHODS: Starting in September 2004 and ending in December 2007, this prospective HIPAA-compliant, institutional review board-approved screening trial, with written informed consent, recruited female patients at elevated risk for breast cancer (eg, personal history of breast cancer or breast cancer in a close relative). A total of 1298 examinations from 779 patients (mean age, 58.6 years; range, 32-91 years) comprised the analyzable data set. A paired study design was used, with each enrolled patient serving as her own control. Patients underwent both DM and stereoscopic DM examinations in a single visit, findings of which were interpreted independently by two experienced radiologists, each using a Breast Imaging Reporting and Data System (BI-RADS) assessment (BI-RADS category 0, 1, or 2). All patients determined to have one or more findings with either or both modalities were recalled for standard diagnostic evaluation. The results of 1-year follow-up or biopsy were used to determine case truth. RESULTS: Compared with DM, stereoscopic DM showed significantly higher specificity (91.2% [1167 of 1279] vs 87.8% [1123 of 1279]; P = .0024) and accuracy (90.9% [1180 of 1298] vs 87.4% [1135 of 1298]; P = .0023) for detection of cancer. Sensitivity for detection of cancer was not significantly different for stereoscopic DM (68.4% [13 of 19]) compared with DM (63.2% [12 of 19], P .99). The recall rate for stereoscopic DM was 9.6% (125 of 1298) and that for DM was 12.9% (168 of 1298) (P = .0018). CONCLUSION: Compared with DM, stereoscopic DM significantly improved specificity for detection of cancer, while maintaining comparable sensitivity. The recall rate was significantly reduced with stereoscopic DM compared with DM. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120382/-/DC1
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