131 research outputs found
DIFFERENTIAL POLYNOMIAL RINGS WHICH ARE GENERALIZED ASANO PRIME RINGS
Let R[x; 6] be a differential polynomialring over a prime Goldie ring R in an
indeterminate x, where 6 is a derivation of R. In this paper, we describe ex�plicitly the group of 6-stable v-R-ideals and using this results, we show that
R[x; 6] is a generalized Asano primering if and only if R is a 6-generalized
Asanoprimering.
Key words : Differential polynomial ring; generalized Asano primering;
prime Goldie ring; 5-stable v-ideal
Crossed product orders over valuation rings II: Tamely ramified crossed product algebras
Let V be a commutative valuation domain of arbitrary K rull-dimension, with quotient field F, let K be a finite Galois extension of F with group G, and let S be the integral closure of V in K. Suppose that one has a 2-cocycle on G that takes values in the group of units of S. Then one can form the crossed product of G over S, S * G, which is a V-order in the central simple F-algebra K * G. If S * G is assumed to be a Dubrovin valuation ring of K * G, then the main result of this paper is that, given a suitable definition of tameness for central simple algebras, K * G is tamely ramified and defectless over F if and only if K is tamely ramified and defectless over F. The residue structure of S * G is also considered in the paper, as well as its behaviour upon passage to Henselization
BOUNDED GENERALIZED DEDEKIND PRIME RINGS
We give several characterizations of bounded generalized Dedekind prime rings in terms of invertible prime ideals and provide examples of PI generalized Dedekind prime rings in which every maximal ideal is localizable
Key Words: Generalized Dedekind prime ring, Invertible ideal, Localizable, Prime
v-ideal.
2010 Mathematics Subject Classification: Primary 16P50, Secondary 13F05,
13F15
Factorizations of Elements in Noncommutative Rings: A Survey
We survey results on factorizations of non zero-divisors into atoms
(irreducible elements) in noncommutative rings. The point of view in this
survey is motivated by the commutative theory of non-unique factorizations.
Topics covered include unique factorization up to order and similarity, 2-firs,
and modular LCM domains, as well as UFRs and UFDs in the sense of Chatters and
Jordan and generalizations thereof. We recall arithmetical invariants for the
study of non-unique factorizations, and give transfer results for arithmetical
invariants in matrix rings, rings of triangular matrices, and classical maximal
orders as well as classical hereditary orders in central simple algebras over
global fields.Comment: 50 pages, comments welcom
Anticorpos antileucotoxina contra Actinobacillus actinomycetemcomitans em amostras de soro e saliva de pacientes com periodontite juvenil localizada
The leukotoxin produced by Actinobacillus actinomycetemcomitans is considered the major virulence factor with potential to cause damage to the host defenses. The present work analyzed the serumal and salivary levels of antibodies against the leukotoxin produced by A. Actinomycetemcomitans, in patients with Localized Juvenile Periodontitis (LJP) and in healthy controls. Additionally, analysis of the immune complex (IC) was carried out in saliva samples . The classic ELISA method, with leukotoxin obtained through Sephadex G-200 gel filtration, and the capture ELISA method, using rabbit anti-A. Actinomycetemcomitans (leucotoxic, FDC Y4, IgG) adsorbed with a non-leukotoxic strain of A. actinomycetemcomitans, were used. The results obtained demonstrated significantly higher serumal levels of IgG in patients with LJP, when they were compared with the healthy controls, both for the classic and capture ELISA methods (p < 0.05). However, no significant differences were observed between the salivary levels of IgG, SIgA and IC in the examined individuals. These results suggest that even though A. actinomycetemcomitans presents virulence factors that affect the immune response, there is immune response to leukotoxin in LJP patients. This increase of IgG in the blood stream might contribute to host defense, limiting the lesion to the periodontal regions already colonized by A. actinomycetemcomitans.A leucotoxina de Actinobacillus actinomycetemcomitans é considerada seu principal fator de virulência com potencial de causar agressão à s defesas do hospedeiro. No presente trabalho, foram analisados os nÃveis séricos e salivares de anticorpos antileucotoxina de A. actinomycetemcomitans em soros e salivas de pacientes com periodontite juvenil localizada (PJL) e controles saudáveis. Adicionalmente, foi realizada a análise de complexo imune (CI) nas amostras de saliva. Foram utilizados os métodos ELISA clássico com a leucotoxina obtida por gel filtração em Sephadex G-200 e ELISA de captura utilizando IgG de coelho anti-A. actinomycetemcomitans FDC Y4 leucotóxico adsorvido com uma cepa da mesma espécie, porém, não leucotóxica. Os resultados obtidos demonstraram nÃveis séricos de IgG significativamente mais elevados em pacientes com PJL em relação aos controles sadios, tanto por ELISA clássico como por ELISA de captura (p < 0,05). No entanto, não foram observadas diferenças entre os nÃveis de IgG, IgA-S e CI nas salivas dos indivÃduos examinados. Estes resultados sugerem que, embora A. actinomycetemcomitans apresente vários fatores de virulência que afetam a resposta imune do hospedeiro, ocorre resposta imune à leucotoxina nos pacientes com PJL. Esse aumento de IgG na circulação sangüÃnea pode contribuir na defesa do hospedeiro, limitando a lesão nas regiões periodontais amplamente colonizadas por A. actinomycetemcomitans
The anti-myeloma activity of a novel purine scaffold HSP90 inhibitor PU-H71 is via inhibition of both HSP90A and HSP90B1
<p>Abstract</p> <p>Background</p> <p>Heat shock protein 90 (HSP90) inhibitors have emerged as a promising class of anti-cancer drugs in both solid and hematologic malignancies. The HSP90 family includes the cytosolic HSP90 (HSP90AA1), the ER paralogue gp96 (HSP90B1) and the mitochondrial member TRAP1 (HSP90L). We evaluated the <it>in vitro </it>anti-tumor activity and mechanism of action of PU-H71, a novel purine scaffold HSP90 inhibitor in human multiple myeloma cell lines.</p> <p>Methods</p> <p>Multiple human myeloma cell lines including cells that are resistant to corticosteroids and bortezimab were treated with PU-H71, followed by analysis of cell viability, cell cycle progression and apoptosis, by flow cytometry and caspase 3 immunoblot. Induction of unfolded protein response was studied by XBP-1 s immunoblot. The role of gp96 was further assessed by small hairpin RNA knockdown of gp96 before treatment with PU-H71.</p> <p>Results</p> <p>PU-H71 has potent <it>in vitro </it>anti-myeloma activity in both drug-sensitive and drug-resistant cell lines. PU-H71 activates the unfolded protein response and induces caspase-dependent apoptosis. The stable gp96 knockdown human myeloma cell line was found to be more resistant to PU-H71 and other HSP90 inhibitors including 17-AAG and 17-DMAG, even though these cells are more sensitive to conventional anti-myeloma drugs.</p> <p>Conclusion</p> <p>We conclude that PU-H71 is a promising drug for the treatment of myeloma. Our finding further suggests that PU-H71 and the geldanamycin analogues work in part by inhibiting the endoplasmic reticulum gp96 along with the cytosolic HSP90.</p
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Genetic resistance to JAK2 enzymatic inhibitors is overcome by HSP90 inhibition
Enzymatic inhibitors of Janus kinase 2 (JAK2) are in clinical development for the treatment of myeloproliferative neoplasms (MPNs), B cell acute lymphoblastic leukemia (B-ALL) with rearrangements of the cytokine receptor subunit cytokine receptor–like factor 2 (CRLF2), and other tumors with constitutive JAK2 signaling. In this study, we identify G935R, Y931C, and E864K mutations within the JAK2 kinase domain that confer resistance across a panel of JAK inhibitors, whether present in cis with JAK2 V617F (observed in MPNs) or JAK2 R683G (observed in B-ALL). G935R, Y931C, and E864K do not reduce the sensitivity of JAK2-dependent cells to inhibitors of heat shock protein 90 (HSP90), which promote the degradation of both wild-type and mutant JAK2. HSP90 inhibitors were 100–1,000-fold more potent against CRLF2-rearranged B-ALL cells, which correlated with JAK2 degradation and more extensive blockade of JAK2/STAT5, MAP kinase, and AKT signaling. In addition, the HSP90 inhibitor AUY922 prolonged survival of mice xenografted with primary human CRLF2-rearranged B-ALL further than an enzymatic JAK2 inhibitor. Thus, HSP90 is a promising therapeutic target in JAK2-driven cancers, including those with genetic resistance to JAK enzymatic inhibitors
Carbon monoxide-Releasing Molecule-2 (CORM-2) attenuates acute hepatic ischemia reperfusion injury in rats
<p>Abstract</p> <p>Background</p> <p>Hepatic ischemia-reperfusion injury (I/Ri) is a serious complication occurring during liver surgery that may lead to liver failure. Hepatic I/Ri induces formation of reactive oxygen species, hepatocyte apoptosis, and release of pro-inflammatory cytokines, which together causes liver damage and organ dysfunction. A potential strategy to alleviate hepatic I/Ri is to exploit the potent anti-inflammatory and cytoprotective effects of carbon monoxide (CO) by application of so-called CO-releasing molecules (CORMs). Here, we assessed whether CO released from CORM-2 protects against hepatic I/Ri in a rat model.</p> <p>Methods</p> <p>Forty male Wistar rats were randomly assigned into four groups (n = 10). Sham group underwent a sham operation and received saline. I/R group underwent hepatic I/R procedure by partial clamping of portal structures to the left and median lobes with a microvascular clip for 60 minutes, yielding ~70% hepatic ischemia and subsequently received saline. CORM-2 group underwent the same procedure and received 8 mg/kg of CORM-2 at time of reperfusion. iCORM-2 group underwent the same procedure and received iCORM-2 (8 mg/kg), which does not release CO. Therapeutic effects of CORM-2 on hepatic I/Ri was assessed by measuring serum damage markers AST and ALT, liver histology score, TUNEL-scoring of apoptotic cells, NFkB-activity in nuclear liver extracts, serum levels of pro-inflammatory cytokines TNF-α and IL-6, and hepatic neutrophil infiltration.</p> <p>Results</p> <p>A single systemic infusion with CORM-2 protected the liver from I/Ri as evidenced by a reduction in serum AST/ALT levels and an improved liver histology score. Treatment with CORM-2 also up-regulated expression of the anti-apoptotic protein Bcl-2, down-regulated caspase-3 activation, and significantly reduced the levels of apoptosis after I/Ri. Furthermore, treatment with CORM-2 significantly inhibited the activity of the pro-inflammatory transcription factor NF-κB as measured in nuclear extracts of liver homogenates. Moreover, CORM-2 treatment resulted in reduced serum levels of pro-inflammatory cytokines TNF-α and IL-6 and down-regulation of the adhesion molecule ICAM-1 in the endothelial cells of liver. In line with these findings, CORM-2 treatment reduced the accumulation of neutrophils in the liver upon I/Ri. Similar treatment with an inactive variant of CORM-2 (iCORM-2) did not have any beneficial effect on the extent of liver I/Ri.</p> <p>Conclusions</p> <p>CORM-2 treatment at the time of reperfusion had several distinct beneficial effects on severity of hepatic I/Ri that may be of therapeutic value for the prevention of tissue damage as a result of I/Ri during hepatic surgery.</p
African ancestry of New World, Bemisia tabaci-whitefly species
Bemisia tabaci whitefly species are some of the world’s most devastating agricultural pests and plant-virus disease vectors. Elucidation of the phylogenetic relationships in the group is the basis for understanding their evolution, biogeography, gene-functions and development of novel control technologies. We report here the discovery of five new Sub-Saharan Africa (SSA) B. tabaci putative species, using the partial mitochondrial cytochrome oxidase 1 gene: SSA9, SSA10, SSA11, SSA12 and SSA13. Two of them, SSA10 and SSA11 clustered with the New World species and shared 84.8‒86.5% sequence identities. SSA10 and SSA11 provide new evidence for a close evolutionary link between the Old and New World species. Re-analysis of the evolutionary history of B. tabaci species group indicates that the new African species (SSA10 and SSA11) diverged from the New World clade c. 25 million years ago. The new putative species enable us to: (i) re-evaluate current models of B. tabaci evolution, (ii) recognise increased diversity within this cryptic species group and (iii) re-estimate divergence dates in evolutionary time
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