Disulfide Biochemistry in 2-Cys Peroxiredoxin: Requirement of Glu50 and Arg146 for the Reduction of Yeast Tsa1 by Thioredoxin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On the construction and labelling of geometrically uniform signal sets in ℤ2 matched to additive quotient groups

We establish the conditions under which it is possible to construct signal sets satisfying the properties of being geometrically uniform and matched to additive quotient groups. Such signal sets consist of subsets of signal spaces identified to integers rings ℤ[i] and ℤ[ω] in ℤ2. © 2008 KSCAM and Springer-Verlag.

Determinants of blood pressure in type 2 diabetic subjects with high occurrence of inadequate glycemic control

Study design: Association study Objective: To analyze the association between different biological/behavioral risk factors and blood pressure in a sample of type 2 diabetes mellitus patients with poor glycemic control. Methods: A sample of 121 type 2 diabetic patients was selected in the Public Healthcare System in a middle size Brazilian city. Blood pressure was measured using an aneroid device, previously calibrated. Six determinants of blood pressure were taken into count: age, hypoglycemic agents, general obesity, abdominal obesity, eating behaviors and physical activity level. Results: The type 2 diabetic patients presented mean age of 60.1±8.9 years-old and, at least, one risk factor. Eating behaviors (OR adj= 0.31 [0.12-0.75]) and sports practice (OR adj= 0.12 [0.02-0.75]) constituted protective factors associated with lower systolic blood pressure. On the other hand, age was positively associated with high systolic blood pressure (OR adj= 3.81 [1.39-10.38]). Patients with 5-6 risk factors, presented higher values of systolic and (F= 3.857; p= 0.011 [post hoc with p= 0.039]), diastolic blood pressure (F= 4.158; p= 0.008 [post hoc with p= 0.036]) and increased occurrence of hypertension (p= 0.010). Conclusion: Our findings indicate that, behavioral variables were important determinants of blood pressure in type 2 diabetic patients with poor glycemic control and clustering of behavioral and biological risk factors increase the hypertension occurrence.

Disulfide Biochemistry in 2-Cys Peroxiredoxin: Requirement of Glu50 and Arg146 for the Reduction of Yeast Tsa1 by Thioredoxin

2-Cys peroxiredoxin (Prx) enzymes are ubiquitously distributed peroxidases that make use of a peroxidatic cysteine (Cys(P)) to decompose hydroperoxides. A disulfide bond is generated as a consequence of the partial unfolding of the alpha-helix that contains Cys(P). Therefore, during its catalytic cycle, 2-Cys Prx alternates between two states, locally unfolded and fully folded. Tsa1 (thiol-specific antioxidant protein 1 from yeast) is by far the most abundant Cys-based peroxidase in Saccharomyces cerevisiae. In this work, we present the crystallographic structure at 2.8 angstrom resolution of Tsa1(C47S) in the decameric form [(alpha(2))(5)] with a DTT molecule bound to the active site, representing one of the few available reports of a 2-Cys Prx (AhpC-Prx1 subfamily) (AhpC, alkyl hydroperoxide reductase subunit C) structure that incorporates a ligand. The analysis of the Tsa1(C47S) structure indicated that G1u50 and Arg146 participate in the stabilization of the Cys(P) alpha-helix. As a consequence, we raised the hypothesis that G1u50 and Arg146 might be relevant to the Cys(P) reactivity. Therefore, Tsa1(E50A) and Tsa1(R146Q) mutants were generated and were still able to decompose hydrogen peroxide, presenting a second-order rate constant in the range of 10(6) M-1 S-1. Remarkably, although Tsa1(E50A) and Tsa1(R146Q) were efficiently reduced by the low-molecular-weight reductant DTT, these mutants displayed only marginal thioredoxin (Trx)-dependent peroxidase activity, indicating that G1u50 and Arg146 are important for the Tsa1-Trx interaction. These results may impact the comprehension of downstream events of signaling pathways that are triggered by the oxidation of critical Cys residues, such as Trx. (C) 2012 Elsevier Ltd. All rights reserved.

Association between matrix metalloproteinase (MMP)-2 polymorphisms and MMP-2 levels in hypertensive disorders of pregnancy

We examined whether two functional polymorphisms (g.-1306 C> T and g.-735 C>T) in matrix metalloproteinase (MMP)-2 gene are associated with preeclampsia (PE) or gestational hypertension (GH), and whether they modify MMP-2 or tissue inhibitor of metalloproteinase (TIMP)-2 plasma concentrations in these hypertensive disorders of pregnancy. We studied 130 healthy pregnant (HP), 130 pregnant with GH, and 133 pregnant with PE. Genomic DNA was extracted from whole blood and genotypes for g.-1306 C>T and g.-735 C>T polymorphisms were determined by Real Time-PCR, using Taqman allele discrimination assays. Haplotypes were inferred using the PHASE program. Plasma MMP-2 and TIMP-2 concentrations were measured by ELISA. The main findings were that pregnant with PE have higher plasma MMP-2 and TIMP-2 concentrations than HP (P<0.05), although the MMP-2/TIMP-2 ratios were similar (P>0.05). Moreover, pregnant with GH have elevated plasma MMP-2 levels and MMP-2/TIMP-2 ratios compared to HP (P<0.05). While MMP-2 genotypes and haplotypes are not linked with hypertensive disorders of pregnancy, MMP-2 genotypes and haplotypes are associated with significant alterations in plasma MMP-2 and TIMP-2 concentrations in preeclampsia (P<0.05). Our findings may help to understand the relevance of MMP-2 and its genetic polymorphisms to the pathophysiology of hypertensive disorders of pregnancy. It is possible that patients with PE and the MMP-2 haplotype combining the C and T alleles for the g.-1306 C>T and g.-735 C>T polymorphisms may benefit from the use of MMPs inhibitors such as doxycycline. However, this possibility remains to be determined. (C) 2012 Elsevier Inc. All rights reserved.

Formfaktor-Bestimmung des semileptonischen K +- pi 0 my +- ny-Zerfalls mit dem NA48/2-Experiment

Der semileptonische Zerfall K^±→π^0 μ^± υ ist ein geeigneter Kanal zur Be-stimmung des CKM-Matrixelementes 〖|V〗_us |. Das hadronische Matrixelement dieses Zerfalls wird durch zwei dimensionslose Formfaktoren f_± (t) beschrieben. Diese sind abhängig vom Impulsübertrag t=〖(p_K-p_π)〗^2 auf das Leptonpaar. Zur Bestimmung von 〖|V〗_us | dienen die Formfaktoren als wichtige Parameter zur Berechnung des Phasenraumintegrals dieses Zerfalls. Eine präzise Messung der Formfaktoren ist zusätzlich dadurch motiviert, dass das Resultat des NA48-Experimentes von den übrigen Messungen der Experimente KLOE, KTeV und ISTRA+ abweicht. Die Daten einer Messperiode des NA48/2 -Experimentes mit offenem Trigger aus dem Jahre 2004 wurden analysiert. Daraus wählte ich 1.8 Millionen K_μ3^±-Zerfallskandidaten mit einem Untergrundanteil von weniger als 0.1% aus. Zur Bestimmung der Formfaktoren diente die zweidimensionale Dalitz-Verteilung der Daten, nachdem sie auf Akzeptanz des Detektors und auf radiative Effekte korrigiert war. An diese Verteilung wurde die theoretische Parameter-abhängige Funktion mit einer Chiquadrat-Methode angepasst. Es ergeben sich für quadratische, Pol- und dispersive Parametrisierung folgende Formfaktoren: λ_0=(14.82±〖1.67〗_stat±〖0.62〗_sys )×〖10〗^(-3) λ_+^'=(25.53±〖3.51〗_stat±〖1.90〗_sys )×〖10〗^(-3) λ_+^''=( 1.40±〖1.30〗_stat±〖0.48〗_sys )×〖10〗^(-3) m_S=1204.8±〖32.0〗_stat±〖11.4〗_(sys ) MeV/c^2 m_V=(877.4±〖11.1〗_stat±〖11.2〗_(sys ) MeV/c^2 LnC=0.1871±〖0.0088〗_stat±〖0.0031〗_(sys )±=〖0.0056〗_ext Λ_+=(25.42±〖0.73〗_stat±〖0.73〗_(sys )±=〖1.52〗_ext )×〖10〗^(-3) Die Resultate stimmen mit den Messungen der Experimente KLOE, KTeV und ISTRA+ gut überein, und ermöglichen eine Verbesserung des globalen Fits der Formfaktoren. Mit Hilfe der dispersiven Parametrisierung der Formfaktoren, unter Verwendung des Callan-Treiman-Theorems, ist es möglich, einen Wert für f_± (0) zu bestimmen. Das Resultat lautet: f_+ (0)=0.987±〖0.011〗_(NA48/2)±〖0.008〗_(ext ) Der für f_+ (0) berechnete Wert stimmt im Fehler gut mit den vorherigen Messungen von KTeV, KLOE und ISTRA+ überein, weicht jedoch um knapp zwei Standardabweichungen von der theoretischen Vorhersage ab.

GLP-2 receptors in human disease: high expression in gastrointestinal stromal tumors and Crohn's disease

Peptide hormones of the glucagon-like peptide (GLP) family play an increasing clinical role, as reported for GLP-1 in diabetes therapy and insulinoma diagnostics. GLP-2, despite its known trophic and anti-inflammatory intestinal actions translated into preliminary clinical studies using the GLP-2 analogue teduglutide for treatment of short bowel syndrome and Crohn's disease, remains poorly characterized in terms of expression of its receptor in tissues of interest. Therefore, the GLP-2 receptor expression was assessed in 237 tumor and 148 non-neoplastic tissue samples with in vitro receptor autoradiography. A GLP-2 receptor expression was present in 68% of gastrointestinal stromal tumors (GIST). Furthermore, GLP-2 receptors were identified in the intestinal myenteric plexus, with significant up-regulation in active Crohn's disease. The GLP-2 receptors in GIST may be used for clinical applications like in vivo targeting with radiolabelled GLP-2 analogues for imaging and therapy. Moreover, the over-expressed GLP-2 receptor in the myenteric plexus may represent the morphological correlate of the clinical target of teduglutide in Crohn's disease.

Juvenile myoclonic epilepsy with photosensitivity in a female with Velocardiofacial syndrome (del(22)(q11.2))--causal relationship or coincidence?

We report on an adolescent female with Velocardiofacial syndrome (del(22)(q11.2)) and an epilepsy phenotype resembling juvenile myoclonic epilepsy (JME). Clinically, the patient has characteristic signs of both disorders. JME has been linked to several chromosomes, but has not been related to 22q11.2 and is rarely observed in other genetic syndromes. We discuss possible explanations for a relationship between the chromosomal aberration and epilepsy as well as the importance of precise delineation of both epilepsy phenotypes and genetic defects in chromosomal disorders.

The role of postoperative prophylactic antibiotics in the treatment of facial fractures: a randomized, double-blind, placebo-controlled pilot clinical study. Part 2: mandibular fractures in 59 patients

The aim of this study was to evaluate the difference between a 5-day and a 1-day postoperative course of antibiotic on the incidence of infection after mandibular fractures involving the alveolus. Sixty-two patients with fractures of the mandible involving the dentoalveolar region were randomly assigned to 2 groups, both of which were given amoxicillin/clavulanic acid 1.2 g intravenously every 8 h from admission until 24 h postoperatively. The 5-day group were then given amoxicillin/clavulanic acid 625 mg orally every 8 h for another 4 days. The 1-day group was given an oral placebo at the same intervals. Follow-up appointments were 1, 2, 4, 6, 12 weeks and 6 months postoperatively. Development of an infection was the primary end point. Fifty-nine of the 62 patients completed this study. Six of the 30 patients in the 5-day group (20%) and 6 out of the 29 in the 1-day group (21%) developed local wound infections. Three of the 6 in the 1-day group developed purulent discharge and swelling. One patient in the 5-day group developed a rash on the trunk. There were no significant differences in the incidence of infection or side effects between the groups. In fractures of the mandible involving the alveolus, a 1-day postoperative course of antibiotic is as effective in preventing infective complications as a 5-day regimen.

Hypofibrinolysis in type 2 diabetes: the role of the inflammatory pathway and complement C3

AIMS/HYPOTHESIS Plasminogen activator inhibitor-1 (PAI-1) has been regarded as the main antifibrinolytic protein in diabetes, but recent work indicates that complement C3 (C3), an inflammatory protein, directly compromises fibrinolysis in type 1 diabetes. The aim of the current project was to investigate associations between C3 and fibrinolysis in a large cohort of individuals with type 2 diabetes. METHODS Plasma levels of C3, C-reactive protein (CRP), PAI-1 and fibrinogen were analysed by ELISA in 837 patients enrolled in the Edinburgh Type 2 Diabetes Study. Fibrin clot lysis was analysed using a validated turbidimetric assay. RESULTS Clot lysis time correlated with C3 and PAI-1 plasma levels (r = 0.24, p < 0.001 and r = 0.22, p < 0.001, respectively). In a multivariable regression model involving age, sex, BMI, C3, PAI-1, CRP and fibrinogen, and using log-transformed data as appropriate, C3 was associated with clot lysis time (regression coefficient 0.227 [95% CI 0.161, 0.292], p < 0.001), as was PAI-1 (regression coefficient 0.033 [95% CI 0.020, 0.064], p < 0.05) but not fibrinogen (regression coefficient 0.003 [95% CI -0.046, 0.051], p = 0.92) or CRP (regression coefficient 0.024 [95% CI -0.008, 0.056], p = 0.14). No correlation was demonstrated between plasma levels of C3 and PAI-1 (r = -0.03, p = 0.44), consistent with previous observations that the two proteins affect different pathways in the fibrinolytic system. CONCLUSIONS/INTERPRETATION Similarly to PAI-1, C3 plasma levels are independently associated with fibrin clot lysis in individuals with type 2 diabetes. Therefore, future studies should analyse C3 plasma levels as a surrogate marker of fibrinolysis potential in this population.