The uncharged surface features surrounding the active site of Escherichia coli DsbA are conserved and are implicated in peptide binding

DsbA is a protein-folding catalyst from the periplasm of Escherichia coli that interacts with newly translocated polypeptide substrate and catalyzes the formation of disulfide bonds in these secreted proteins. The precise nature of the interaction between DsbA and unfolded substrate is not known. Here, we give a detailed analysis of the DsbA crystal structure, now refined to 1.7 Angstrom, and present a proposal for its interaction with peptide. The crystal structure of DsbA implies flexibility between the thioredoxin and helical domains that may be an important feature for the disulfide transfer reaction. A hinge point for domain motion is identified-the typo IV beta-turn Phe 63-Met 64-Gly 65-Gly 66, which connects the two domains. Three unique features on the active site surface of the DsbA molecule-a groove, hydrophobic pocket, and hydrophobic patch-form an extensive uncharged surface surrounding the active-sits disulfide. Residues that contribute to these surface features are shown to be generally conserved in eight DsbA homologues. Furthermore, the residues immediately surrounding the active-site disulfide are uncharged in all nine DsbA proteins. A model for DsbA-peptide interaction has been derived from the structure of a human thioredoxin:peptide complex. This shows that peptide could interact with DsbA in a manner similar to that with thioredoxin. The active-site disulfide and all three surrounding uncharged surface features of DsbA could, in principle, participate in the binding or stabilization of peptide.

From anatomy to angioscopy: 164 years of crocodilian cardiovascular research, recent advances, and speculations

This paper present: a synthesis of current research on the crocodilian cardiovascular system with a view to encourage discussion and debate about the intricacies of this unique system and to provide ideas and suggestions for future studies. Innovative experimental approaches combined with new technologies have helped to resolve the complex flow and pressure patterns observed during non-shunting conditions that predominate in resting instrumented animals and during pulmonary to systemic shunting, which has been observed to occur spontaneously and during diving. The mechanisms and structures that may induce and regulate shunting are presented and the functional significance of a pulmonary to systemic shunt is discussed. (C) 1997 Elsevier Science Inc.

Influence of the interaction between nodal fibroblast and breast cancer cells on gene expression

Our aim was to evaluate the interaction between breast cancer cells and nodal fibroblasts, by means of their gene expression profile. Fibroblast primary cultures were established from negative and positive lymph nodes from breast cancer patients and a similar gene expression pattern was identified, following cell culture. Fibroblasts and breast cancer cells (MDA-MB231, MDA-MB435, and MCF7) were cultured alone or co-cultured separated by a porous membrane (which allows passage of soluble factors) for comparison. Each breast cancer lineage exerted a particular effect on fibroblasts viability and transcriptional profile. However, fibroblasts from positive and negative nodes had a parallel transcriptional behavior when co-cultured with a specific breast cancer cell line. The effects of nodal fibroblasts on breast cancer cells were also investigated. MDA MB-231 cells viability and migration were enhanced by the presence of fibroblasts and accordingly, MDA-MB435 and MCF7 cells viability followed a similar pattern. MDA-MB231 gene expression profile, as evaluated by cDNA microarray, was influenced by the fibroblasts presence, and HNMT, COMT, FN3K, and SOD2 were confirmed downregulated in MDA-MB231 co-cultured cells with fibroblasts from both negative and positive nodes, in a new series of RT-PCR assays. In summary, transcriptional changes induced in breast cancer cells by fibroblasts from positive as well as negative nodes are very much alike in a specific lineage. However, fibroblasts effects are distinct in each one of the breast cancer lineages, suggesting that the inter-relationships between stromal and malignant cells are dependent on the intrinsic subtype of the tumor.

Gene expression profile of residual breast cancer after doxorubicin and cyclophosphamide neoadjuvant chemotherapy

In breast cancer patients, primary chemotherapy is associated with the same survival benefits as adjuvant chemotherapy. Residual tumors represent a clinical challenge, Lis they may be resistant to additional cycles of the same drugs. Our aim was to identify differential transcripts expressed in residual tumors, after neoadjuvant chemotherapy, that might be related with tumor resistance. Hence, 16 patients with paired tumor samples, collected before and after treatment (4 cycles doxorubicin/cyclophosphamide, AC) had their gene expression evaluated on cDNA microarray slides containing 4,608 genes. Three hundred and eighty-nine genes were differentially expressed (paired Student`s t-test, pFDR<0.01) between pre- and post-chemotherapy samples and among the regulated functions were the JNK cascade and cell death. Unsupervised hierarchical clustering identified one branch comprising exclusively, eight pre-chemotherapy samples and another branch, including the former correspondent eight post-chemotherapy samples and other 16 paired pre/post-chemotherapy samples. No differences in clinical and tumor parameters could explain this clustering. Another group of I I patients with paired samples had expression of selected genes determined by real-time RT-PCR and CTGF and DUSP1 were confirmed more expressed in post- as compared to pre-chemotherapy samples. After neoadjuvant chemotherapy some residual samples may retain their molecular signature while others present significant changes in their gene expression, probably induced by the treatment. CTGF and DUSP1 overexpression in residual samples may be a reflection of resistance to further administration of AC regimen.

The chemistry of 5-oxodihydroisoxazoles .19. The synthesis and photolysis of N-thioacylisoxazol-5(2H)-ones

5-Oxodihydroisoxazoles react with thiocarbonyl chlorides to afford N-thioacylisoxazol-5(2H)-ones which lose carbon dioxide under photochemical conditions and undergo intramolecular cyclisation of the iminocarbene to afford thiazoles, However, in some cases loss of carbon dioxide is accompanied by loss of sulfur, giving 1,3-oxazin-6-ones.

Leprosy in transplant recipients: report of a case after liver transplantation and review of the literature

P>Leprosy still is an important public health problem in several parts of the world including Brazil. Unlike the diseases caused by other mycobacteria, the incidence and clinical presentation of leprosy seems little affected in immunosuppressed patients. We report the first case, to our knowledge, of a liver transplant patient who developed multi-bacillary leprosy. The patient presented with papules and infiltrated plaques with loss of sensation suggestive of leprosy 3.5 years after living-related liver transplantation for autoimmune hepatitis. A skin biopsy showing non-caseating macrophagic granulomas, neuritis, and intact acid-fast bacilli on Fite-Faraco stain, confirmed the diagnosis of borderline lepromatous leprosy. The donor of the liver did not show any evidence of leprosy. During follow-up, the patient presented 2 episodes of upgrading leprosy type I reactions, 1 mild before leprosy treatment, and 1 moderate 3 months after receiving standard multi-drug treatment (rifampicin, clofazimine, and dapsone). These reactions were accompanied by increase in liver function tests, especially of canalicular enzymes. This reaction occurred despite the patient`s triple immunosuppression regimen. The moderate reaction was successfully treated with further immunosuppression (prednisone, 0.5 mg/kg). Currently, the patient is asymptomatic, off leprosy medication, with routine liver transplant follow-up. The dilemmas in diagnosis and management of such a case are discussed and the literature on leprosy in transplant recipients is reviewed.

Effects of Aerobic Training on Psychosocial Morbidity and Symptoms in Patients With Asthma A Randomized Clinical Trial

Background: Asthma symptoms reduce patients daily activities, impair their health-related quality of life (HRQoL), and increase their reports of anxiety and depress, all of which seem to be related to a decrease in asthma control. Aerobic exercise training is known to improve aerobic fitness and reduce dyspnea in asthmatics; however, its effect in reducing psychologic distress and symptoms remains poorly understood. We evaluated the role of an aerobic training program in improving HRQoL (primary aim) and reducing psychologic distress and asthma symptoms (secondary aims) for patients with moderate or severe persistent asthma. Methods: A total of 101 patients were randomly assigned to either a control group or an aerobic training group and studied during the period between medical consultations. Control group patients (educational program plus breathing exercises) (n = 51) and training group patients (educational program plus breathing exercises plus aerobic training) (n = 50) were followed twice a week during a 3-month period. HRQoL and levels of anxiety and depression were quantified before and after treatment. Asthma symptoms were evaluated monthly. Results: At 3 months, the domains (physical limitations, frequency of symptoms, and psychosocial) and total scores of HRQoL, significantly improved only in the training group patients (P < .001); the number of asthma-symptom-free days and anxiety and depression levels also significantly improved in this group (P < .001). In addition, a linear relationship between improvement in aerobic capacity and the days without asthma symptoms was observed (r = 0.47; P < .01). Conclusions: Our results suggest that aerobic training can play an important role in the clinical management of patients with persistent asthma. Further, they may be especially useful for patients with higher degrees of psychosocial distress.

Macrocycle formation through carbon acid-formaldehyde condensation reactions of bis(propane-1,2-diamine)- and bis (2-methylpropane-1,2-diamine)-copper(II) ions

The reaction of the bis(1,2-diamine) copper(II) complexes of racemic propane-1,2-diamine (pn) and 2-methylpropane-1,2-diamine (dmen) with formaldehyde and nitroethane in methanol under basic conditions yields minor macrocyclic condensation products in addition to the major acyclic products. Where C-pendant methyl groups on the pair of coordinated diamines are in cis dispositions, the first -NH-CH2-C(CH3)(NO2)-CH2-NH- ring formation occurs at amine pairs distant from these C-methyl substituents, and further reaction to yield a macrocycle is not observed. However, where the C-methyl substituents are in trans dispositions, the chemistry proceeds to yield the macrocycle. Commencing with pn, trans-(6,13-diammonio-2,6,9,13-tetramethyl-1,4,7,10-tetraazacyclotetradecane)copper(II) perchlorate formed and crystallized in the space group P2(1)/n, with a 9.782(2), b 9.2794(6), c 17.017(4) Angstrom, beta 103.24(1)degrees. The copper ion is found in a square-planar environment, with the two methyl groups of the pn residues and the pairs of introduced pendant groups all in trans arrangements.

Development of an Evaluation Scale for Sitting and Standing From the Ground for Children With Duchenne Muscular Dystrophy

The authors developed an evaluation scale for sit-stand from the ground for children with Duchenne muscular dystrophy (DMD) and tested its reliability. The construction occurred in stages: (a) the characterization of the movement in healthy children, (b) the characterization of the movement in children with DMD, (c) the elaboration of the 1st version of the scale and the manual, (d) the evaluation by experts and readjustments, and (e) the analysis of inter- and intraexaminer reliability and correlation with the Vignos Scale, age, and time for the execution of the activity. The scale comprehended 3 phases for sitting and 5 for the standing. A very good repeatability of the measures of sitting and standing (ICC = 0.89 and 0.84, respectively) and excellent reproducibility (ICC = 0.93 and 0.92, respectively) was demonstrated. The Kappa coefficient for the 8 phases in the interexaminer analysis varied from 0.77 to 1.00 (excellent reliability), and in the intraexaminer analysis varied from 0.80 to 1.00 (excellent reliability). Good correlation was found between the variables on the Vignos Scale (age: r = 0.58; stand: r = 0.56). The scale is a reliability instrument that allows evaluation of the activity of sitting and standing in children with DMD.

The chemistry of novolac resins .3. C-13 and N-15 nmr studies of curing with hexamethylenetetramine

The reactions between novolac resins and hexamethylenetetramine (HMTA) which occur on curing have been studied by C-13 and N-15 high-resolution n.m.r. in both solution and the solid state. Strong evidence for the existence of many curing intermediates is obtained. New curing intermediates are reported along with experimental data to support previously postulated intermediates. The initial curing reactions between novolac and HMTA produce various substituted benzoxazines and benzylamines. Thermal decomposition/oxidation and further reactions of these initial intermediates generate methylene linkages between phenolic rings for chain extension and cross-linking. Among the three kinds of methylene linkages, the para-para methylene linkages are formed at relatively lower temperatures. Various imine, amide and imide side-products also concurrently appear during the process. The initial amount of HMTA plays a critical role in the curing reactivity and chemical structures of the cured resins. The lower the amount of HMTA, the lower the temperature at which curing occurs, and the lower the amount of the nitrogen-containing side-products in the finally cured resins. The ortho-linked intermediates are relatively stable, and can remain in the cured resins up to higher temperatures. The study provides an extensive description of the curing reactions of novolac resins. (C) 1997 Elsevier Science Ltd.

The Role of Carcinoembriogenic Antigen in Predicting Response and Survival to Neoadjuvant Chemoradiotherapy for Distal Rectal Cancer

PURPOSE: Carcinoembriogenic antigen (CEA) is the most frequently used tumor marker in rectal cancer. A decrease in carcinoembriogenic antigen after radical surgery is associated with survival in these patients. Neoadjuvant chemoradiotherapy may lead to significant primary tumor downstaging, including complete tumor regression in selected patients. Therefore, we hypothesized that a decrease in CEA after neoadjuvant chemoradiotherapy could reflect tumor response to chemoradiotherapy, affecting final disease stage and ultimately survival. METHODS: Patients with distal rectal cancer managed by neoadjuvant chemoradiotherapy and available pretreatment and postchemoradiotherapy levels of CEA were eligible for the study. Outcomes studied included final disease stage, relapse, and survival, and these were compared according to initial CEA level, postchemoradiotherapy CEA level, and the reduction in CEA. RESULTS: Overall 170 patients were included. Postchemoradiotherapy CEA levels < 5 ng/ml were associated with increased rates of complete clinical response and pathologic response. Additionally, postchemoradiotherapy CEA levels < 5 ng/ml were associated with increased overall and disease-free survival (P = 0.01 and P = 0.03). There was no correlation between initial CEA level or reduction in CEA and complete response or survival. CONCLUSION: A postchemoradiotherapy CEA level < 5 ng/ml is a favorable prognostic factor for rectal cancer and is associated with increased rates of earlier disease staging and complete tumor regression. Postchemoradiotherapy CEA levels may be useful in decision making for patients who may be candidates for alterative treatment strategies.

IS SPLENECTOMY A DYSLIPIDEMIC INTERVENTION? EXPERIMENTAL RESPONSE OF SERUM LIPIDS TO DIFFERENT DIETS AND OPERATIONS

Spleen removal may be recommended during organ transplantation in ABO-incompatible recipients as well as for hypoperfusion of the grafted liver, besides conventional surgical indications, but elevation of serum lipids has been observed in certain contexts. Aiming to analyze the influence of two dietary regimens on lipid profile, an experimental study was conducted. Methods: Male Wistar rats (n = 86, 333.0 +/- 32.2 g) were divided in four groups: group 1: controls; group 2: sham operation; group 3: total splenectomy; group 4: subtotal splenectomy with upper pole preservation; subgroups A (cholesterol reducing chow) and B (cholesterol-rich mixture) were established, and diet was given during 90 days. Total cholesterol (Tchol), high-density lipoprotein (HDL), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), and triglycerides were documented. Results: After total splenectomy, hyperlipidemia ensued with cholesterol-reducing chow. Tchol, LDL, VLDL, triglycerides, and HDL changed from 56.4 +/- 9.2, 24.6 +/- 4.7, 9.7 +/- 2.2, 48.6 +/- 11.1, and 22.4 +/- 4.3 mg/dL to 66.9 +/- 11.4, 29.9 +/- 5.9, 10.9 +/- 2.3, 54.3 +/- 11.4, and 26.1 +/- 5.1 mg/dL, respectively. Upper pole preservation inhibited abnormalities of Tchol, HDL, VLDL, and triglycerides, and LDL decreased (23.6 +/- 4.9 vs. 22.1 +/- 5.1, P = 0.002). Higher concentrations were triggered by splenectomy and cholesterol-enriched diet (Tchol 59.4 +/- 10.1 vs. 83.9 +/- 14.3 mg/dL, P = 0.000), and upper-pole preservation diminished without abolishing hyperlipidemia (Tchol 55.9 +/- 10.0 vs. 62.3 +/- 7.8, P = 0.002). Conclusions: After splenectomy, hyperlipidemia occurred with both diets. Preservation of the upper pole tended to correct dyslipidemia in modality A and to attenuate it in subgroup B. (c) 2008 Wiley-Liss, Inc. Microsurgery 29:154-160, 2009.

Effects of oxide promoters on metal dispersion and metal-support interactions in Ni catalysts supported on activated carbon

Various oxide-promoted Ni catalysts supported on activated carbon were prepared, and the effect of promoters on the surface structure and properties of Ni catalysts was studied. Physical adsorption (Na adsorption), thermogravimetric analysis (TGA), temperature-programmed desorption (TPD), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to characterize the catalysts. It is found that nickel is fairly uniformly distributed in the pores of the carbon support. Addition of promoters produces a more homogeneous distribution of nickel ion in carbon. However, distributions of promoters in the pores are varying. Addition of promoters increases the dispersion of nickel in carbon. Promoters also change the interaction between the carbon and Ni, resulting in significantly different behaviors of catalysts under various environments. CaO and MgO promoters improve the reactivity of nickel catalysts with O-2 but retard the interaction between nickel oxide and carbon. La2O3 shows some inhibiting effect on the interactions between nickel oxide and oxygen as well as carbon.

Genotypic distribution of hepatitis C among hepatitis C and HIV co-infected patients in Brazil

Information on hepatitis C virus (HCV) genotypic distribution among HIV-HCV co-infected patients is lacking in Brazil as well as other Latin American countries. The objective of this study was to evaluate the level of exposure to different risk factors associated with HCV transmission among a group of co-infected patients and to characterize the genotypic distribution of HCV in this cluster. A series of 100 HIV-HCV co-infected patients was analysed. The data to be analysed were collected from specific laboratory tests. Information was collected through a questionnaire. HCV genotyping was carried out by sequencing the 5 ` non-coding region of HCV. Chi-square and Fischer association tests or Kruskal-Wallis test were used to study the association between HCV transmission-related variables and the established genotypes. In conclusion, exposure to multiple risk factors associated with HCV transmission was common among HIV co-infected patients and an association between HCV genotype 3 and intravenous drug user was observed.

Impact of antimicrobial resistance on the treatment and outcome of patients with sepsis

Antimicrobial therapy is one of the main stones of sepsis therapy. A recent study of septic shock patients showed that each hour of delay in antimicrobial administration during the ensuing 6 h after the onset of hypotension was associated with a decrease in survival rates. However, many questions regarding the impact of infection caused by antimicrobial-resistant pathogens on the mortality of patients with sepsis still need to be clarified. There is a lack of fair studies in the literature. Most studies have had inadequate sample size, inadequate adjustment for predictors of adverse outcomes, and inadequate definition of appropriate antibiotic therapy. Despite the fact that appropriate therapy is essential to treat sepsis, it seems that severity of underlying diseases and comorbidities are more important than resistance, although the studies were not well designed to examine the real impact of resistance on outcome. Finally, new technologies such as microarray that can identify different microorganisms, genes of resistance, and virulence in a few hours might have a great impact on the treatment of sepsis due to antimicrobial-resistant pathogens in the future.