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.     

Docosahexanoic acid antagonizes TNF-α-induced necroptosis by attenuating oxidative stress,ceramide production,lysosomal dysfunction,and autophagic features

Objective

It was previously reported that docosahexanoic acid (DHA) reduces TNF-α-induced necrosis in L929 cells. However, the mechanisms underlying this reduction have not been investigated. The present study was designed to investigate cellular and biochemical mechanisms underlying the attenuation of TNF-α-induced necroptosis by DHA in L929 cells.

Methods

L929 cells were pre-treated with DHA prior to exposure to TNF-α, zVAD, or Necrostatin-1 (Nec-1). Cell death and survival were assessed by MTT and caspase activity assays, and microscopic visualization. Reactive oxygen species (ROS) were measured by flow cytometry. C16- and C18-ceramides were measured by mass spectrometry. Lysosomal membrane permeabilization (LMP) was evaluated by fluorescence microscopy and flow cytometry using Acridine Orange. Cathepsin L activation was evaluated by immunoblotting and fluorescence microscopy. Autophagy was assessed by immunoblotting of LC3-II and Beclin.

Results

Exposure of L929 cells to TNF-α alone for 24 h induced necroptosis, as evidenced by the inhibition of cell death by Nec-1, absence of caspase-3 activity and Lamin B cleavage, and morphological analysis. DHA attenuated multiple biochemical events associated with TNF-α-induced necroptosis, including ROS generation, ceramide production, lysosomal dysfunction, cathepsin L activation, and autophagic features. DHA also attenuated zVAD-induced necroptosis but did not attenuate the enhanced apoptosis and necrosis induced by the combination of TNF-α with Actinomycin D or zVAD, respectively, suggesting that its protective effects might be limited by the strength of the cell death insult induced by TNF-α.

Conclusions

DHA effectively attenuates TNF-α-induced necroptosis and autophagy, most likely via its ability to inhibit TNF-α-induced sphingolipid metabolism and oxidative stress. These results highlight the role of this Omega-3 fatty acid in antagonizing inflammatory cell death.     

Active tuberculosis in inflammatory bowel disease patients under treatment from an endemic area in Latin America

BACKGROUNDThere has been an increase in cases of inflammatory bowel disease (IBD) in recent years. There is also greater access and availability of immunosuppressive and biological agents, which increase the risk of opportunistic infection despite improving the quality of life and promoting mucosal healing. Tuberculosis (TB) remains a public health problem, and it has a high incidence in several countries. Therefore, knowledge of the risk of developing TB in patients with IBD is important.AIMTo evaluate the risk of active TB in patients with IBD under treatment from an endemic area in Latin America.METHODSA standard questionnaire included demographic variables, clinical aspects of IBD disease, history of active TB during treatment, active TB characteristics and evolution, initial screening and results and time from the start of anti-tumor necrosis factor alpha (TNFα) to TB development.RESULTSAzathioprine, anti-TNFα and the combination of these two drugs were associated with a higher risk of active TB incidence. The TNFα blockers increased the relative risk of developing active TB compared to other treatments. All four multivariable models showed that the use of TNFα blockers alone or in combination with azathioprine was an important risk factor for the incidence of active TB. After adjustment for sex, age, type of IBD and latent TB, anti-TNFα with azathioprine increased the relative risk to 17.8 times more than conventional treatment. Late TB, which was diagnosed 3 mo after the start of anti-TNFα, was the most frequent.CONCLUSIONTreatment with anti-TNFα increased the risk of active TB in IBD patients from an endemic area in Latin America. This risk was increased when anti-TNFα was combined with azathioprine. The time from the beginning of the treatment to the active TB diagnosis suggests a new TB infection.     

Conserved features of intermediates in amyloid assembly determine their benign or toxic states

Some amyloid-forming polypeptides are associated with devastating human diseases and others provide important biological functions. For both, oligomeric intermediates appear during amyloid assembly. Currently we have few tools for characterizing these conformationally labile intermediates and discerning what governs their benign versus toxic states. Here, we examine intermediates in the assembly of a normal, functional amyloid, the prion-determining region of yeast Sup35 (NM). During assembly, NM formed a variety of oligomers with different sizes and conformation-specific antibody reactivities. Earlier oligomers were less compact and reacted with the conformational antibody A11. More mature oligomers were more compact and reacted with conformational antibody OC. We found we could arrest NM in either of these two distinct oligomeric states with small molecules or crosslinking. The A11-reactive oligomers were more hydrophobic (as measured by Nile Red binding) and were highly toxic to neuronal cells, while OC-reactive oligomers were less hydrophobic and were not toxic. The A11 and OC antibodies were originally raised against oligomers of Aβ, an amyloidogenic peptide implicated in Alzheimer's disease (AD) that is completely unrelated to NM in sequence. Thus, this natural yeast prion samples two conformational states similar to those sampled by Aβ, and when assembly stalls at one of these two states, but not the other, it becomes extremely toxic. Our results have implications for selective pressures operating on the evolution of amyloid folds across a billion years of evolution. Understanding the features that govern such conformational transitions will shed light on human disease and evolution alike.     

Oral lesions in renal transplant

To prevent rejection of kidney transplants, patients must be kept in immunosuppressive therapy for a long time, which includes the use of drugs such as cyclosporine, azathioprine, cyclophosphamide, and prednisone. The action of these drugs reduces the general immune response of transplant patients and thus increases their susceptibility to infections. Moreover, these drugs increase the potential of developing lesions. Therefore, oral hygiene in kidney transplant recipients contributes to maintenance of the transplanted organ and its function. Thus, an investigation of oral lesions could be counted as a notable work. The aim of this study was to investigate oral lesions in a group of 21 kidney transplant patients under immunosuppressive therapy attended during a 1-year period in the Nephrology Department of the Federal University of Sergipe, Brazil. Data related to sex, age, etiology of renal disease, types of renal transplant, time elapsed after transplantation, immunosuppressive treatment, use of concomitant agents, and presence of oral lesions were obtained. All patients received a kidney transplant from a living donor, and the mean posttransplantation follow-up time was 31.6 months; 71.5% used triple immunosuppressive therapy with cyclosporine A, azathioprine, and prednisone. Ten patients were also treated with calcium-channel blockers. Of the 21 transplant patients, 17 (81%) presented oral lesions. Gingival overgrowth was the most common alteration, followed by candidiasis and superficial ulcers. One case of spindle cell carcinoma of the lower lip was observed. Oral cavity can harbor a variety of manifestations related to renal transplantation under immunosuppressive therapy.     

Craniomaxillofacial features in hereditary multiple exostosis

Hereditary multiple exostosis is the most common form of bone dysplasia. This entity is also known as diaphyseal aclasis, hereditary deforming chondrodysplasia, multiple hereditary exostoses, multiple osteochondromatosis, multiple cartilaginous exostosis, dyschondroplasia, and Ehrenfried disease. It is an inherited autosomal dominant disease with predominance in males and a benign condition characterized by the presence of multiple exostosis or osteochondromas arising from long and flat bones.Osteochondroma is the most common benign tumor in persons between 10 and 30 years of age. It accounts for 20% to 50% of all benign tumors and 10% to 15% of all bone tumors. It is more commonly located at the level of the metaphysis of long bones. However, osteochondroma is rare at the level of the facial bones and skull base. It has been reported in the maxillary sinus and in different parts of the mandible, such as the condyle, ramus, body, and symphyseal region. It is very uncommon in the coronoid process and occipital bone.Jacob disease, or osteochondroma of the mandibular coronoid process, is a benign skeletal tumor that is rare in the oral and maxillofacial skeleton. A review of the literature revealed only 41 histologically proven cases of 52 reported cases. To the best of the authors' knowledge this is the first clinical report of bilateral coronoid osteochondroma and associated occipital exostosis in a patient with hereditary multiple exostosis.     

Coronary artery anomalies

Coronary artery anomalies (CAAs) are a rare entity but their true incidence in the general population has yet to be determined. Most CAAs are asymptomatic, but they are nevertheless the second leading cause of sudden death in apparently healthy young athletes. The new imaging methods available to cardiologists, including CT angiography and MRI, now enable noninvasive diagnosis and characterization of these anomalies. The authors review the literature and present a retrospective study of 360 consecutive patients who underwent cardiac CT angiography. Demographic, clinical and angiographic characteristics were studied. The incidence of CAAs in this population was 2.69%. In order to better characterize this disorder, including diagnostic strategy, screening, treatment and prognosis, the authors suggest the establishment of a national registry of cardiac CT angiography. Such a registry would fill the existing gap in information on exams performed in the country, enriching current knowledge about this disease and noninvasive cardiac imaging in Portugal.     

Congenital hydrocephalus in the northeast of Brazil: epidemiological aspects, prenatal diagnosis, and treatment

Purpose

Congenital hydrocephalus (CH) has higher proportions in developing countries such as Brazil, reaching rates of 3.16:1,000 newborns. Early diagnosis is essential and can be done during the second trimester of pregnancy, highlighting the importance of regular prenatal care. Our objective is to describe the epidemiological profile of children with CH in the state of Bahia.

Methods

Consecutive medical records of patients with CH, aged less than 2years and operated at a pediatric reference hospital between September 2009 and September 2012, were reviewed.

Results

One hundred twenty-one children underwent ventricular peritoneal shunt (VP shunt) due to CH. As for prenatal care, 38 % of pregnant women did it regularly. Males predominated with 56 % of cases with a median age of 3 months, and 68 % were from the countryside area. The most frequent clinical manifestations were bulging fontanelle (37 %) and increased head circumference (30 %). There were 13 (11 %) reports of complications associated with VP shunts. There were nine deaths (7 %), and respiratory complications were the main cause.

Conclusions

Public health measures are the key to increase mothers’ knowledge about the importance of regular prenatal monitoring. There was a predominance of male children, with a median age of 3 months, with the majority coming from the countryside.