Molecular characteristics of extended-spectrum beta-lactamase-producing Escherichia coli from Rio de Janeiro, Brazil

Twenty-five extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli clinical isolates from Rio de Janeiro, Brazil were characterized by isoelectric focusing, PCR and sequencing of bla(ESBL) genes, plasmid-mediated quinolone resistance determinants, phylogenetic groups, replicon typing, pulsed-field electrophoresis, and multilocus sequencing typing. Twenty-three (92%) ESBL-producing E. coli isolates were positive for bla(CTX-M) genes, aac(6`)-lb-cr, and qnrB. Genetic relatedness of ESBL producers clustered seven (28%) CTX-M-15-producing isolates as sequence type (ST) 410, clonal complex (CC) 23, and two (8%) as clone O25-ST131. Our results illustrate the predominance of phylo-group A (52%), ST410 (CC 23) and CTX-M-15 among ESBL-producing E. coli isolates from hospitals in Rio de Janeiro.

The Role of Toll-Like Receptor 2 in the Recognition of Aggregatibacter actinomycetemcomitans

Background: Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans) is a Gram-negative bacterium present in the oral cavity and is usually associated with localized aggressive periodontitis. Isolated antigens from A. actinomycetemcomitans can activate innate immune cells through Toll-like receptors (TLRs), which are molecules that recognize structural components conserved among microorganisms. In this study, we evaluate the role of TLR2 in the recognition of A. actinomycetemcomitans. Methods: Macrophages and neutrophils from knockout mice with targeted disruption of TLR2 (TLR2(-/-) mice) and wild-type mice were collected and used for the subsequent assays. The production of cytokines and chemokines was evaluated by enzyme-linked immunosorbent assay (ELISA), and the presence of apoptotic cells was determined by flow cytometry. In addition, the mechanisms that modulate the outcome of A. actinomycetemcomitans-induced periodontal disease in TLR2(-/-) mice were examined. Results: The results show that TLR2-deficient mice developed more severe periodontitis after A. actinomycetemcomitans infection, characterized by significantly higher bone loss and inflammatory cell migration to periodontal tissues. The inflammatory cell influx into the peritoneal cavities of TLR2(-/-) mice was three-fold lower than that observed for the littermate controls. A significantly diminished production of the cytokines tumor necrosis factor-alpha and interleukin-1 beta as well as the chemokine CC-ligand-5 in the peritoneal cavities of TLR2(-/-) mice was observed. In addition, a high frequency of apoptotic cells in the inflammatory exudates from TLR2(-/-) mice was observed. Phagocytosis and nitric oxide production was diminished in cells from TLR2(-/-) mice, facilitating the dissemination of the pathogen to the spleen. Conclusion: The results of this study highlight the involvement of TLR2 in recognizing A. actinomycetemcomitans and its essential role in controlling A. actinomycetemcomitans infection. J Periodontot 2009,80:2070-2019.

The 434(G > C) polymorphism in the eosinophil cationic protein gene and its association with tissue eosinophilia in oral squamous cell carcinomas

Objective: The aim of this study was to investigate the prevalence of the Eosinophil cationic protein (ECP)-gene polymorphism 434(G > C) in oral squamous cell carcinoma (OSCC) patients and its association with tumor-associated tissue eosinophilia (TATE), demographic, clinical, and microscopic variables. Methods: The ECP genotypes of 165 healthy individuals and 157 OSCC patients were detected by PCR-RFLP analysis after cleavage of the amplified DNA sequence with enzyme PstI. TATE was obtained by morphometric analysis. Chi-square test or Fisher`s exact test was used to analyze the association of ECP-gene polymorphism 434(G > C) with TATE, demographic, clinical, and microscopic variables in OSCC patients. Disease-free survival and overall survival were calculated by the Kaplan-Meier product-limit actuarial method and the comparison of the survival curves were performed using log rank test. Results: Most of healthy individuals (53.33%) and OSCC patients (57.97%) were heterozygous for the ECP 434(G > C) polymorphism. Based on numerical differences, our results showed that OSCC patients with intense TATE and at least one C allele had a higher frequency of bilateral neck dissection, local recurrence, vascular embolization, involved resection margins, and postoperative radiotherapy. No statistically significant differences on survival rates were found in OSCC patients presenting different ECP 434(G > C) genotypes. Conclusions: These results suggest a tendency towards a poor clinical outcome in OSCC patients with intense TATE and 434GC/CC genotypes, probably due to an ECP genetic variant with altered cytotoxic activity.

The mu-way intersection problem for m-cycle systems

An m-cycle system of order upsilon is a partition of the edge-set of a complete graph of order upsilon into m-cycles. The mu -way intersection problem for m-cycle systems involves taking mu systems, based on the same vertex set, and determining the possible number of cycles which can be common to all mu systems. General results for arbitrary m are obtained, and detailed intersection values for (mu, m) = (3, 4), (4, 5),(4, 6), (4, 7), (8, 8), (8, 9). (For the case (mu, m)= (2, m), see Billington (J. Combin. Des. 1 (1993) 435); for the case (Cc,m)=(3,3), see Milici and Quattrochi (Ars Combin. A 24 (1987) 175. (C) 2001 Elsevier Science B.V. All rights reserved.

The metamorphosis of lambda-fold 4-wheel systems into lambda-fold 4-cycle systems

A 4-wheel is a simple graph on 5 vertices with 8 edges, formed by taking a 4-cycle and joining a fifth vertex (the centre of the 4-wheel) to each of the other four vertices. A lambda -fold 4-wheel system of order n is an edge-disjoint decomposition of the complete multigraph lambdaK(n) into 4-wheels. Here, with five isolated possible exceptions when lambda = 2, we give necessary and sufficient conditions for a lambda -fold 4-wheel system of order n to be transformed into a lambda -fold Ccyde system of order n by removing the centre vertex from each 4-wheel, and its four adjacent edges (retaining the 4-cycle wheel rim), and reassembling these edges adjacent to wheel centres into 4-cycles.

A genetic polymorphism of matrix metalloproteinase 9 (MMP-9) affects the changes in circulating MMP-9 levels induced by highly active antiretroviral therapy in HIV patients

We examined whether two functional polymorphisms (g.-1562C>T and g.-90(CA)14-24) in the matrix metalloproteinase (MMP)-9 gene or MMP-9 haplotypes affect the circulating levels of pro-MMP-9 and pro-MMP-9/TIMP-1 (tissue inhibitor of metalloproteinase-1) ratios in AIDS patients, and modulate alterations in these biomarkers after highly active antiretroviral therapy (HAART). We studied 82 patients commencing HAART. Higher pro-MMP-9 concentrations and pro-MMP-9/TIMP-1 ratios were found in CT/TT patients compared with CC patients. HAART decreased pro-MMP-9 levels and pro-MMP-9/TIMP-1 ratios in CT/TT patients, it did not modify pro-MMP-9 levels and it increased pro-MMP-9/TIMP-1 ratios in CC patients. The g.-90(CA)14-24 polymorphism, however, produced no significant effects. Moreover, we found no significant differences in HAART-induced changes in plasma pro-MMP-9, TIMP-1 and pro-MMP-9/TIMP-1 ratios when different MMP-9 haplotypes were compared. These findings suggest that the g.-1562C>T polymorphism affects pro-MMP-9 levels in patients with AIDS and modulates the alterations in pro-MMP-9 levels caused by HAART, thus possibly affecting the risk of cardiovascular complications. The Pharmacogenomics Journal (2009) 9, 265-273; doi: 10.1038/tpj.2009.13; published online 21 April 2009

Mindreading and moral awareness in popular and rejected preschoolers

This study sought to examine links among young children's peer relations, their moral understanding in terms of the ability to distinguish lies from mistakes, and their theory-of-mind development. Based on sociometric measures, 109 children with a mean age of 4.8 years were divided into groups of popular and rejected preschoolers. Rejected children who had a stable mutual friend scored higher on measures of moral understanding and theory of mind than did rejected children without such friendships. Similarly, popular children who had a stable mutual friendship outperformed other popular children on mindreading, although their moral understanding was no better than that of the popular group who lacked mutual friends. Hierarchical multiple regression analyses revealed that peer popularity was a significant independent predictor of children's moral understanding after any effects of verbal maturity, age and theory-of-mind were statistically controlled. Moreover, having a reciprocal stable friendship made a significant independent contribution to the explanation of individual differences in mindreading, over and above age and verbal maturity, which also contributed significantly. These results are discussed in terms of conversational, cognitive, and emotional processes in the development of social cognition.

Social cognition, language acquisition and the development of the theory of mind

Theory of Mind (ToM) is the cognitive achievement that enables us to report our propositional attitudes, to attribute such attitudes to others, and to use such postulated or observed mental states in the prediction and explanation of behavior. Most normally developing children acquire ToM between the ages of 3 and 5 years, but serious delays beyond this chronological and mental age have been observed in children with autism, as well is in those with severe sensory impairments. We examine data from Studies of ToM in normally developing children and those with deafness, blindness, autism and Williams syndrome, as well as data from lower primates, in a search for answers to key theoretical questions concerning the origins, nature and representation of knowledge about the mind. In answer to these, we offer a framework according to which ToM is jointly dependent upon language and social experience, and is produced by a conjunction of language acquisition with children's growing social understanding, acquired through conversation and interaction with others. We argue that adequate language and adequate social skills are jointly causally sufficient, and individually causally necessary, for producing ToM. Thus our account supports a social developmental theory of the genesis of human cognition, inspired by the work of Sellars and Vygotsky.

Children's incipient ability to distinguish mistakes from lies: An Italian investigation

We report a study in which Italian children aged 3 to 5 years were given situations requiring a distinction between lies and honest mistakes. As in previous research, the children displayed an incipient grasp of the lie-mistake distinction with regard to situations involving falsehoods about edibility of a substance that had been contaminated. However, children of all ages often regarded instances of both lies and mistakes as negative rather than restricting their judgements of naughtiness to the lying alone. The results are discussed in terms of the characteristics of Italian language and culture such as the connotations of words used to indicate mistakes'' and references to anger in labelling a variety of emotional events.

Valproic acid has temporal variability in urinary clearance of metabolites

The reasons for the intra- and interindividual variability in the clearance of valproic acid (VPA) have not been completely characterized. The aim of this study was to examine day-night changes in the clearance of 3-oxo-valproate (3-oxo-VPA), 4-hydroxy-valproate (4-OH-VPA), and valproic acid glucuronides under steady state. Six diurnally active healthy male volunteers ingested 200 mg sodium valproate 12 hourly, at 0800 and 2000, for 28 days. On the last study day, two sequential 12-h urine samples were collected commencing at 2000 the evening before. Plasma samples were obtained at the end of each collection. Following alkaline hydrolysis, urine was analyzed for concentrations of VPA, 3-oxo-VPA, and 4-OH-VPA. A separate aliquot was assayed for creatinine (CR). The plasma concentrations of VPA, 3-oxo-VPA, 2-en-VPA, and CR were determined. The analysis of VPA and its metabolites was performed by CC-MS. There was an increase in plasma 3-oxo-VPA concentration at 0800, sampling as compared to 2000 sampling (p < .05). The urinary excretion of 3-oxo-VPA and VPA glucuronides were decreased between 2000 and 0800, compared to between 0800, and 2000, by 30% and 50% respectively (p < .05). These results indicate a nocturnal decrease in renal clearance of 3-oxo-VPA rather than a decrease in the beta -oxidation of VPA at night. These differences were not explained by differences between the sampling periods in CR excretion. These results indicate the importance of collecting samples of 24-h duration when studying metabolic profiles of VPA.

In situ zymography: topographical considerations

In situ gelatin zymography is a simple technique providing valuable information about the cellular and tissue localization of gelatinases. Until recently, the use of this technique has been confined to soft, relatively homogeneous tissue. In this report in situ zymography has been utilized to assess the sub-lamellar location of gelatinases in the hard, semi-keratinized epidermal layer and the adjacent soft connective tissue matrix of the dermis of the equine hoof. We show that alterations in the orientation at which the tissue is dipped and withdrawn from the emulsion cause profound alterations in emulsion thickness. Microscopic Variations in the surface topography of frozen tissue sections also influence emulsion thickness making interpretation of the results difficult. Given these results, researchers must be aware of potential variations in zymographic analysis may be influenced by physical tissue parameters in addition to suspected gelatinase activity. (C) 2001 Elsevier Science B.V. All rights reserved.

In vitro evidence for a bacterial pathogenesis of equine laminitis

Utilizing an in vitro laminitis explant model, we have investigated how bacterial broth cultures and purified bacterial proteases activate matrix metalloproteinases (MMPs) and alter structural integrity of cultured equine lamellar hoof explants. Four Gram-positive Streptococcus spp. and three Gram-negative bacteria all induced a dose-dependent activation of MMP-2 and MMP-9 and caused lamellar explants to separate. MMP activation was deemed to have occurred if a specific MMP inhibitor, batimastat, blocked MMP activity and prevented lamellar separation. Thermolysin and streptococcal pyrogenic exotoxin B (SpeB) both separated explants dose-dependently but only thermolysin was inhibitable by batimastat or induced MMP activation equivalent to that seen with bacterial broths. Additionally, thermolysin and broth MMP activation appeared to be cell dependent as MMP activation did not occur in isolation. These results suggest the rapid increase in streptococcal species in the caecum and colon observed in parallel with carbohydrate induced equine laminitis may directly cause laminitis via production of exotoxin(s) capable of activating resident MMPs within the lamellar structure. Once activated, these MMPs can degrade key components of the basement membrane (BM) hemidesmosome complex, ultimately separating the BM from the epidermal basal cells resulting in the characteristic laminitis histopathology of hoof lamellae. While many different causative agents have been evaluated in the past, the results of this study provide a unifying aetiological mechanism for the development of carbohydrate induced equine laminitis. (C) 2001 Elsevier Science B.V. All rights reserved.

Compact clinical MRI magnet design using a multilayer current density approach

In this work, a new method of optimization is successfully applied to the theoretical design of compact, actively shielded, clinical MRI magnets. The problem is formulated as a two-step process in which the desired current densities on multiple, cc-axial surface layers are first calculated by solving Fredholm equations of the first kind. Non-linear optimization methods with inequality constraints are then invoked to fit practical magnet coils to the desired current densities. The current density approach allows rapid prototyping of unusual magnet designs. The emphasis of this work is on the optimal design of short, actively-shielded MRI magnets for whole-body imaging. Details of the hybrid numerical model are presented, and the model is used to investigate compact, symmetric, and asymmetric MRI magnets. Magnet designs are presented for actively-shielded, symmetric magnets of coil length 1.0 m, which is considerably shorter than currently available designs of comparable dsv size. Novel, actively-shielded, asymmetric magnet designs are also presented in which the beginning of a 50-cm dsv is positioned just 11 cm from the end of the coil structure, allowing much improved access to the patient and reduced patient claustrophobia. Magn Reson Med 45:331540, 2001. (C) 2001 Wiley-Liss, Inc.

Relationship of XIST expression and responses of ovarian cancer to chemotherapy

Expression profiling to characterize cancer pharmacology has become a new approach to discover novel molecular targets for prognostic markers and cancer therapy. In a study to compare the global RNA expression profiles between primary and recurrent ovarian tumors from the same patient, we have identified XIST (inactive X chromosome-specific transcripts) as the most differentially expressed gene that was down-regulated in the recurrent tumor. XIST encodes a spliced noncoding polyadenylated transcript that is unique in being expressed exclusively from the inactive X chromosome and is involved in the X-inactivation process. Subsequent characterization of XIST expression in a panel of female cancer cell lines showed that the expression level of XIST correlates significantly with Taxol sensitivity. The clinical relevance of this observation is demonstrated by the strong association between XIST RNA levels and disease-free periods of ovarian cancer patients in a group of 21 ovarian cancer cases with Taxol in the therapeutic regiments. Cytogenetic studies on ovarian cancer cell lines indicated that loss of inactive X chromosome is one mechanism for the loss of XIST transcripts in the cell lines. Our data suggest that XIST expression may be a potential marker for chemotherapeutic responses in ovarian cancer.

Twisting and planarization in push-pull ethylenes

As determined by X-ray crystallography, Meldrum's acid derivatives 8–19 feature dihedral angles around the central CC double bonds between 3 and 83°. Hydrogen bonds between substituents RHN and the carbonyl groups favour near-planarity. Sterically demanding substituents favour large dihedral angles and zwitterionic structures as in formula 20. AM1 calculations of the structures are in excellent agreement with the experimental X-ray data, provided a dielectric field is incorporated (?= 40). This can be ascribed to the highly polar (zwitterionic) nature of the molecules. It is further predicted that all these molecules, including those that are stabilised in a planar form by intramolecular hydrogen bonds, undergo rapid rotation about the central CC bonds at room temperature. DFT calculations incorporating a dielectric field model (PCM) are in excellent agreement with the near-perpendicular arrangement of the alkene moiety in 19.