Thiopurine-methyltransferase variants in inflammatory bowel disease:Prevalence and toxicity in Brazilian patients

AIM:To analyze the prevalence of thiopurine-methyltransferase(TPMT)genotypes and their associationwith drug toxicity in inflammatory bowel disease(IBD)patients from southeastern Brazil.METHODS:A total of 219 consecutive patients with IBD,of which 146 had Crohn’s disease and 73 had ulcerative colitis,regularly seen at the outpatient unit of the Division of Gastroenterology at the University Hospital Pedro Ernesto of the State University of Rio de Janeiro,a tertiary referral center,were enrolled in this study from February 2009 to January 2011.We analyzed the presence of major TPMT genetic variants(TPMT*2,*3A,*3C)in IBD patients by means of a specific allele and RFLP-PCR.Genomic DNA was isolated from peripheral blood leukocytes by proteinase-K/Sodium Dodecyl Sulfate digestion and phenol-chloroform extraction.TPMT*2(C238G),TPMT*3A(G460A/A719G),and TPMT*3C(A719G)genotypes were detected by real-time polymerase chain reaction followed by direct sequencing with specific primers.Clinical data were systematically recorded,and correlated with the genotype results.RESULTS:The distribution of the selected TPMT gene polymorphism TPMT*2(C238G),TPMT*3A(G460A/A719G),and TPMT*3C(A719G)genotypes was 3.6%,5.4%,and 7.7%of the patients,respectively.Among the side effects recorded from patients taking azathioprine,14 patients presented with pancreatitis and/or an elevation of pancreatic enzymes,while 6 patients had liver toxicity,and 2 patients exhibited myelosuppression/neutropenia.TPMT polymorphisms were detected in 37/219 patients(8 heterozygous for*2,11 heterozygous for*3A,and 18 heterozygous for*3C).No homozygotic polymorphisms were found.Despite the prevalence of the TPMT*3C genotype,no differences among the genotype frequencies were significant.Although no association was detected regarding myelotoxicity or hepatotoxicity,a trend towards the elevation of pancreatic enzymes was observed for TPMT*2 and TPMT*3C genotypes.CONCLUSION:The prevalence of TPMT genotypes was high among Brazilian patients.Variants genes*2and*3C may be associated with azathioprine pancreatic toxicity in a IBD southeastern Brazilian population.     

Human liver stem/progenitor cells decrease serum bilirubin in hyperbilirubinemic Gunn rat

AIM:To test the ability of adult-derived human liver stem/progenitor cells(ADHLSC)from large scale cultures to conjugate bilirubin in vitro and in bilirubin conjugation deficient rat.METHODS:ADHLSC from large scale cultures were tested for their phenotype and for their capacity to conjugate bilirubin in vitro after hepatogenic differentiation.In vivo,Gunn rats[uridine diphosphate-glucuronosyltransferase 1A1(UGT1A1)deficient animal]were injected with ADHLSC and cryopreserved hepatocytes(positive control).Two,4,13 and 27 wk posttransplantation,transplanted Gunn rat bilirubin serum levels were determined by high performance liquid chromatography.Human cell engraftment of trans-planted cells was assessed 27 wk post-transplantation using immunohistochemistry and RTqPCR.RESULTS:Large scale culture conditions do not modified ADHLSC phenotype,ADHLSC were able to specifically conjugate bilirubin.ADHLSC were intraportally injected into Gunn rats and blood UCB was measured at different times post-transplantation,infused-Gunn rats exhibited a metabolic effect 3 mo post-transplantation and maintained over a 6 mo period.ADHLSC engraftment into Gunn rat’s liver was demonstrated by RTqPCR and immunohistochemistry against albumin and UGT1A1.CONCLUSION:ADHLSC from large scale cultures are efficient in conjugating bilirubin in vitro and in restoring a deficient metabolic function(reducing bilirubin level)in hyperbilirubinemic rats.     

Electrospinning of polyhydroxyalkanoate fibrous scaffolds: effects on electrospinning parameters on structure and properties

In this study, electrospinning was used to prepare ultrafine fibers from PHAs with different chemical compositions: P(3HB) and copolymers: P(3HB-co-4HB), P(3HB-co-3HV), and P(3HB-co-3HHx). The main process parameters that influence ultrafine fiber diameter and properties (polymer concentration, solution feeding rate, working distance, and applied voltage) have been investigated and their effects evaluated. The study revealed electrospinning parameters for the production of high-quality ultrafine fibers and determined which parameters should be varied to tailor the properties of the products. This study is the first to compare biological and physical-mechanical parameters of PHAs with different chemical compositions as dependent upon the fractions of monomers constituting the polymers and ultrafine fiber orientation. Mechanical strength of aligned ultrafine fibers prepared from different PHAs is higher than that of randomly oriented ones; no significant effect of ultrafine fiber orientation on surface properties has been found. None of the fibrous scaffolds produced by electrospinning from PHAs had any adverse effects on attachment, growth, and viability of NIH 3T3 mouse fibroblast cells, and all of them were found to be suitable for tissue engineering applications.     

Fatty acid profiles in Leishmania spp. isolates with natural resistance to nitric oxide and trivalent antimony

Fatty acids, especially those from phospholipids (PLFA), are essential membrane components that are present in relatively constant proportions in biological membranes under natural conditions. However, under harmful growth conditions, such as diseases, environmental changes, and chemical exposure, the fatty acid proportions might vary. If such changes could be identified and revealed to be specific for adverse situations, they could be used as biomarkers. Such biomarkers could facilitate the identification of virulence and resistance mechanisms to particular chemotherapeutic agents. Therefore, specific biomarkers could lead to better therapeutic decisions that would, in turn, enhance treatment effectiveness. The objective of this study was to compare the fatty acid profiles of trivalent antimony and nitric oxide (NO)-resistant and -sensitive Leishmania chagasi and Leishmania amazonensis isolates. Fatty acid methyl esters (FAMEs) were obtained from total lipids (MIDI), ester-linked lipids (ELFA), and ester-linked phospholipids (PLFA). FAMEs were analyzed by chromatography and mass spectrometry. Species- or resistance-associated differences in FAME profiles were assessed by nonmetric multidimensional scaling, multiresponse permutation procedures, and indicator species analyses. The isolate groups had different MIDI-FAME profiles. However, neither the ELFA nor PLFA profiles differed between the sensitive and resistant isolates. Levels of the fatty acid 18:1 Δ9c were increased in sensitive isolates (p?<?0,001), whereas the fatty acid 20:4 Δ5,8,11,14 showed the opposite trend (p?<?0.01). We conclude that these two fatty acids are potential biomarkers for NO and antimony resistance in L. chagasi and L. amazonensis and that they could be helpful in therapeutic diagnoses.     

Chitosan-g-oligo/polylactide copolymer non-woven fibrous mats containing protein: from solid-state synthesis to electrospinning

Graft-copolymers based on bioresorbable synthetic (oligo-/polylactide) and natural (chitosan and collagen/gelatin) components were synthesized through solid-state reactive co-extrusion and used for fabrication of fibrous non-woven mats via the electrospinning technique. The effect of the macromolecular features of the initial components on the copolymer characteristics was evaluated using FTIR-spectroscopy, differential scanning calorimetry and elemental analysis. Dynamic light scattering analysis showed that the copolymers have a tendency to form stable ultra-fine dispersions with a mean size of macromolecular aggregates of 150 nm within chlorinated solvents. The copolymer-containing non-woven fibrous mats were fabricated via an electrospinning procedure using chloroform as a solvent. An effect of the copolymer composition on the casting solution''s viscosity, conductivity and surface tension was evaluated. Scanning electron microscopy showed that the obtained mats consist of randomly distributed fibers with a mean size of ∼5 μm and a more complex morphology than mats fabricated from neat polylactide. The proposed mechanochemical approach to obtain hybrid copolymeric compositions differs from typical liquid-phase methods in terms of high efficiency, simplicity and cleanness.

Amphiphilic chitosan-g-oligo/polylactide graft-copolymers were synthesized through solid-state reactive co-extrusion and used for fabrication of fibrous non-woven mats via the electrospinning technique using chloroform as a solvent.     

Mobile hydrogen carbonate acts as proton acceptor in photosynthetic water oxidation

Cyanobacteria, algae, and plants oxidize water to the O₂ we breathe, and consume CO₂ during the synthesis of biomass. Although these vital processes are functionally and structurally well separated in photosynthetic organisms, there is a long-debated role for CO₂/ in water oxidation. Using membrane-inlet mass spectrometry we demonstrate that acts as a mobile proton acceptor that helps to transport the protons produced inside of photosystem II by water oxidation out into the chloroplast’s lumen, resulting in a light-driven production of O₂ and CO₂. Depletion of from the media leads, in the absence of added buffers, to a reversible down-regulation of O₂ production by about 20%. These findings add a previously unidentified component to the regulatory network of oxygenic photosynthesis and conclude the more than 50-y-long quest for the function of CO₂/ in photosynthetic water oxidation.Oxygenic photosynthesis in cyanobacteria, algae, and higher plants leads to the reduction of atmospheric CO₂ to energy-rich carbohydrates. The electrons needed for this process are extracted in a cyclic, light-driven process from water that is split into dioxygen (O₂) and protons. This reaction is catalyzed by a penta-µ-oxo bridged tetra-manganese calcium cluster (Mn₄CaO₅) within the oxygen-evolving complex (OEC) of photosystem II (PSII) (1–4). The possible roles of inorganic carbon, , in this process have been a controversial issue ever since Otto Warburg and Günter Krippahl (5) reported in 1958 that oxygen evolution by PSII strictly depends on CO₂ and therefore has to be based on the photolysis of H₂CO₃ (“Kohlensäure”) and not of water. These first experiments were indirect and, as became apparent later, were wrongly interpreted (6–8). Several research groups followed up on these initial results and identified two possible sites of C_i interaction within PSII (reviewed in refs. 9–12). Functional and spectroscopic studies showed that facilitates the reduction of the secondary plastoquinone electron acceptor (Q_B) of PSII by participating in the protonation of . Binding of (or ) to the nonheme Fe between the quinones Q_A and Q_B was recently confirmed by X-ray crystallography (3, 13, 14). Despite this functional role at the acceptor side, the very tight binding of to this site makes it impossible for the activity of PSII to be affected by changing the C_i level of the medium; instead inhibitors such as formate need to be added to induce the acceptor-side effect (15). Consequently, the water-splitting electron-donor side of PSII has also been studied intensively (for recent reviews, see refs. 11 and 12). Although a tight binding of C_i near the Mn₄CaO₅ cluster is excluded on the basis of X-ray crystallography (3, 14), FTIR spectroscopy (16), and mass spectrometry (17, 18), the possibility that a weakly bound affects the activity of PSII at the donor side remains a viable option (reviewed in refs. 10 and 19).In the present study using higher plant PSII membranes, we specifically evaluate a recently suggested role of weakly bound , namely, that it acts as an acceptor for, and transporter of, protons produced by water splitting in the OEC (20–22).     

Hodgkin lymphoma patients in first remission: routine positron emission tomography/computerized tomography imaging is not superior to clinical follow‐up for patients with no residual mass

There is no consensus regarding optimal follow‐up mode for Hodgkin lymphoma (HL) patients that achieve complete remission following chemotherapy or combined chemo‐ and radiation therapy. Several studies demonstrated high sensitivity of positron emission tomography/computerized tomography (PET/CT) in detecting disease progression; however, these techniques are currently not recommended for routine follow‐up. This retrospective study conducted in two Israeli (N = 291) and one New Zealand academic centres (N = 77), compared a group of HL patients, followed‐up with routine imaging every 6 months during the first 2 years after achieving remission, once in the third year, with additional dedicated studies performed due to symptoms or physical findings (Group I) to a group of patients without residual masses who underwent clinically‐based surveillance with dedicated imaging upon relapse suspicion (Group II). Five‐year overall survival (OS) was 94% and median time to relapse was 8·6 months for both modes. Relapse rates in Groups I and II were 13% and 9%, respectively. During the first 3 years of follow‐up, 47·5 and 4·7 studies were performed per detected relapse in Groups I and II, respectively. The current study demonstrated no benefit in either progression‐free survival (PFS) or OS in HL patients followed by routine imaging versus clinical follow‐up. The cost was 10 times higher for routine imaging.     

LABORATORY EVALUATION OF THE DEVELOPMENT OF Aedes aegypti IN TWO SEASONS: INFLUENCE OF DIFFERENT PLACES AND DIFFERENT DENSITIES

Aedes aegypti is an important vector in Brazil being the main vector of the dengue-fever. This paper employs survival curves to describe the time in days from larvae to adult forms of Aedes aegypti raised, individually and collectively, and compares it during winter and spring when positioned inside and outside a laboratory. The study was conducted in São Vicente, a coastal city in Southeastern Brazil. The lowest water temperature in winter and in spring was 20 °C and the highest was 26 °C in spring. Higher and more stable temperatures were measured in the intra compared to the peri in both seasons. Consequently, larvae positioned in the intra resulted in the lowest median time to develop in the individual and collective experiment (nine and ten days, respectively). At least 25% of the larvae positioned in the intra in the individual experiment in the spring took only seven days to reach adulthood. Sex ratios and the median time development by sex did not show significant differences. These results indicate that efforts to control Aedes aegypti must be continuous and directed mainly to prevent the intra-domiciliary sites that can be infested in a week in order to reduce the human-vector contact.