Toxoplasma gondii in the peripheral blood of patients with acute and chronic toxoplasmosis

Background and aims Toxoplasmic retinochoroiditis may recur months or years after the primary infection. Rupture of dormant cysts in the retina is the accepted hypothesis to explain recurrence. Here, the authors present evidence supporting the presence of Toxoplasma gondii in the peripheral blood of immunocompetent patients. Methods Direct observation by light microscopy and by immunofluorescence assay was performed, and results were confirmed by PCR amplification of parasite DNA. Results The authors studied 20 patients from Erechim, Brazil, including acute infected patients, patients with recurrent active toxoplasmic retinochoroiditis, patients with old toxoplasmic retinal scars, and patients with circulating IgG antibodies against T gondii and absence of ocular lesions. Blood samples were analysed, and T gondii was found in the blood of acutely and chronically infected patients regardless of toxoplasmic retinochoroiditis. Conclusions The results indicate that the parasite may circulate in the blood of immunocompetent individuals and that parasitaemia could be associated with the reactivation of the ocular disease.

A new model of outbred genetically selected mice which present a strong acute inflammatory response in the absence of complement component C5

Mice selected for a strong (AIRmax) or weak (AIRmin) acute inflammatory response present different susceptibilities to bacterial infections, autoimmune diseases and carcinogenesis. Variations in these phenotypes have been also detected in AIRmax and AIRmin mice rendered homozygous for Slc11a1 resistant (R) and susceptible (S) alleles. Our aim was to investigate if the phenotypic differences observed in these mice was related to the complement system. AIRmax and AIRmin mice and AIRmax and AIRmin groups homozygous for the resistance (R) or susceptibility (S) alleles of the solute carrier family 11a1 member (Slc11a1) gene, formerly designated Nramp-1. While no difference in complement activity was detected in sera from AIRmax and AIRmin strains, all sera from AIRmax Slc11a1 resistant mice (AIRmax(RR)) presented no complement-dependent hemolytic activity. Furthermore, C5 was not found in their sera by immunodiffusion and, polymerase chain reaction and DNA sequencing of its gene demonstrated that AIRmax(RR) mice are homozygous for the C5 deficient (D) mutation previously described in A/J. Therefore, the C5D allele was fixed in homozygosis in AIRmax(RR) line. The AIRmax(RR) line is a new experimental mouse model in which a strong inflammatory response can be triggered in vivo in the absence of C5.

INSULIN REGULATES CYTOKINES AND INTERCELLULAR ADHESION MOLECULE-1 GENE EXPRESSION THROUGH NUCLEAR FACTOR-kappa B ACTIVATION IN LPS-INDUCED ACUTE LUNG INJURY IN RATS

Diabetic patients have increased susceptibility to infection, which may be related to impaired inflammatory response observed in experimental models of diabetes, and restored by insulin treatment. The goal of this study was to investigate whether insulin regulates transcription of cytokines and intercellular adhesion molecule 1 (ICAM-1) via nuclear factor-kappa B (NF-kappa B) signaling pathway in Escherichia coli LIPS-induced lung inflammation. Diabetic male Wistar rats (alloxan, 42 mg/kg, iv., 10 days) and controls were instilled intratracheally with saline containing LPS (750 mu g/0.4 mL) or saline only. Some diabetic rats were given neutral protamine Hagedorn insulin (4 IU, s.c.) 2 h before LIPS. Analyses performed 6 h after LPS included: (a) lung and mesenteric lymph node IL-1 beta, TNF-alpha, IL-10, and ICAM-1 messenger RNA (mRNA) were quantified by real-time reverse transcriptase-polymerase chain reaction; (b) number of neutrophils in the bronchoalveolar lavage (BAL) fluid, and concentrations of IL-1 beta, TNF-alpha, and IL-10 in the BAL were determined by the enzyme-linked immunosorbent assay; and (c) activation of NF-kappa B p65 subunit and phosphorylation of I-kappa B alpha were quantified by Western blot analysis. Relative to controls, diabetic rats exhibited a reduction in lung and mesenteric lymph node IL-1 beta (40%), TNF-alpha (similar to 30%), and IL-10 (similar to 40%) mRNA levels and reduced concentrations of IL-1 beta (52%), TNF-alpha (62%), IL-10 (43%), and neutrophil counts (72%) in the BAL. Activation of NF-kappa B p65 subunit and phosphorylation of I-kappa B alpha were almost suppressed in diabetic rats. Treatment of diabetic rats with insulin completely restored mRNA and protein levels of these cytokines and potentiated lung ICAM-1 mRNA levels (30%) and number of neutrophils (72%) in the BAL. Activation of NF-kappa B p65 subunit and phosphorylation of I-kappa B alpha were partially restored by insulin treatment. In conclusion, data presented suggest that insulin regulates transcription of proinflammatory (IL-1 beta, TNF-alpha) and anti-inflammatory (IL-10) cytokines, and expression of ICAM-1 via the NF-kappa B signaling pathway.

Serine-like proteolytic enzymes correlated with differential pathogenicity in patients with acute Acanthamoeba keratitis

P>Acute ocular infection due to free-living amoebae of the genus Acanthamoeba is characterized by severe pain, loss of corneal transparency and, eventually, blindness. Proteolytic enzymes secreted by trophozoites of virulent Acanthamoeba strains have an essential role in the mechanisms of pathogenesis, including adhesion, invasion and destruction of the corneal stroma. In this study, we analysed the relationship between the extracellular proteases secreted by clinical isolates of Acanthamoeba and the clinical manifestations and severity of disease that they caused. Clinical isolates were obtained from patients who showed typical symptoms of Acanthamoeba keratitis. Trophozoites were cultivated axenically, and extracellular proteins were collected from cell culture supernatants. Secreted enzymes were partially characterized by gelatin and collagen zymography. Acanthamoeba trophozoites secreted proteases with different molecular masses, proteolysis rates and substrate specificities, mostly serine-like proteases. Different enzymatic patterns of collagenases were observed, varying between single and multiple collagenolytic activities. Low molecular weight serine proteases were secreted by trophozoites associated with worse clinical manifestations. Consequently, proteolytic enzymes of some Acanthamoeba trophozoites could be related to the degree of their virulence and clinical manifestations of disease in the human cornea.

Risk factors for dengue virus infection in rural Amazonia: Population-based cross-sectional surveys

A comparison of dengue virus (DENV) antibody levels in paired serum samples collected from predominantly DENV-naive residents in an agricultural settlement in Brazilian Amazonia (baseline seroprevalence, 18.3%) showed a seroconversion rate of 3.67 episodes/100 person-years at risk during 12 months of follow-up. Multivariate analysis identified male sex, poverty, and migration from extra-Amazonian states as significant predictors of baseline DENY seropositivity, whereas male sex, a history of clinical diagnosis of dengue fever, and travel to an urban area predicted subsequent seroconversion. The laboratory surveillance of acute febrile illnesses implemented at the study site and in a nearby town between 2004 and 2006 confirmed 11. DENV infections among 102 episodes studied with DENV IgM detection, reverse transcriptase-polymerise chain reaction, and virus isolation; DENV-3 was isolated. Because DENV exposure is associated with migration or travel, personal protection measures when visiting high-risk urban areas may reduce the incidence of DENV infection in this rural population.

Infection rates and genotypes of Trypanosoma rangeli and T. cruzi infecting free-ranging Saguinus bicolor (Callitrichidae), a critically endangered primate of the Amazon Rainforest

Parasites of wild primates are important for conservation biology and human health due to their high potential to infect humans. In the Amazon region, non-human primates are commonly infected by Trypanosoma cruzi and T rangeli, which are also infective to man and several mammals. This is the first survey of trypanosomiasis in a critically endangered species of tamarin, Saguinus bicolor (Callitrichidae), from the Brazilian Amazon Rainforest. Of the 96 free-ranging specimens of S. bicolor examined 45 (46.8%) yielded blood smears positive for trypanosomes. T rangeli was detected in blood smears of 38 monkeys (39.6%) whereas T. cruzi was never detected. Seven animals (7.3%) presented trypanosomes of the subgenus Megatrypanum. Hemocultures detected 84 positive tamarins (87.5%). Seventy-two of 84 (85.7%) were morphologically diagnosed as T rangeli and 3 (3.1%) as T. cruzi. Nine tamarins (9.4%) yielded mixed cultures of these two species, which after successive passages generated six cultures exclusively of T. cruzi and two of T rangeli, with only one culture remaining mixed. Of the 72 cultures positive for T rangeli, 62 remained as established cultures and were genotyped: 8 were assigned to phylogenetic lineage A (12.9%) and 54 to lineage B (87.1%). Ten established cultures of T. cruzi were genotyped as TCI lineage (100%). Transmission of both trypanosome species, their potential risk to this endangered species and the role of wild primates as reservoirs for trypanosomes infective to humans are discussed. (C) 2008 Elsevier B.V. All rights reserved.

Severe novel influenza A (H1N1) infection in cancer patients

Patients and methods: Clinical data from all patients admitted with acute respiratory failure due to novel viral H1N1 infection were reviewed. Lung tissue was submitted for viral and bacteriological analyses by real-time RT-PCR, and autopsy was conducted on all patients who died. Results: Eight patients were admitted, with ages ranging from 55 to 65 years old. There were five patients with solid organ tumors (62.5%) and three with hematological malignancies (37.5%). Five patients required mechanical ventilation and all died. Four patients had bacterial bronchopneumonia. All deaths occurred due to multiple organ failure. A milder form of lung disease was present in the three cases who survived. Lung tissue analysis was performed in all patients and showed diffuse alveolar damage in most patients. Other lung findings were necrotizing bronchiolitis or extensive hemorrhage. Conclusions: H1N1 viral infection in patients with cancer can cause severe illness, resulting in acute respiratory distress syndrome and death. More data are needed to identify predictors of unfavorable evolution in these patients.

Experimental Chemotherapy against Trypanosoma cruzi Infection Using Ruthenium Nitric Oxide Donors

The ruthenium NO donors of the group trans-[Ru(NO)(NH(3))(4)L](n+), where the ligand (L) is N-heterocyclic H(2)O, SO(3)(2 -), or triethyl phosphite, are able to lyse Trypanosoma cruzi in vitro and in vivo. Using half-maximal (50%) inhibitory concentrations against bloodstream trypomastigotes (IC(50)(try)) and cytotoxicity data on mammalian V-79 cells (IC(50)(V79)), the in vitro therapeutic indices (TIs) (IC(50)(V79)/IC(50)(try)) for these compounds were calculated. Compounds that exhibited an in vitro TI of >= 10 and trypanocidal activity against both epimastigotes and trypomastigotes with an IC(50)(try/epi) of <= 100 mu M were assayed in a mouse model for acute Chagas` disease, using two different routes (intraperitoneal and oral) for drug administration. A dose-effect relationship was observed, and from that, the ideal dose of 400 nmol/kg of body weight for both trans-[Ru(NO)(NH(3))(4)isn](BF(4))(3) (isn, isonicotinamide) and trans-[Ru(NO)(NH3) 4imN](BF4) 3 (imN, imidazole) and median (50%) effective doses (ED50) of 86 and 190 nmol/kg, respectively, were then calculated. Since the 50% lethal doses (LD(50)) for both compounds are higher than 125 mu mol/kg, the in vivo TIs (LD(50)/ED(50)) of the compounds are 1,453 for trans-[Ru(NO)(NH(3))(4)isn](BF(4))(3) and 658 for trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3). Although these compounds exhibit a marked trypanocidal activity and are able to react with cysteine, they exhibit very low activity in T. cruzi -glycosomal glyceraldehyde-3-phosphate dehydrogenase tests, suggesting that this enzyme is not their target. The trans-[Ru(NO)(NH(3))(4)isn](BF(4))(3) and trans-[Ru(NO)(NH(3))(4)imN](BF(4))(3) compounds are able to eliminate amastigote nests in myocardium tissue at 400-nmol/kg doses and ensure the survival of all infected mice, thus opening a novel set of therapies to try against trypanosomatids.

Serum protein concentrations, including acute phase proteins, in calves experimentally infected with Salmonella Dublin

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

Experimental acute canine monocytic ehrlichiosis: clinicopathological and immunopathological findings

Clinical signs, humoral and cellular immune responses, and microscopic and gross tissue alterations resulting from acute experimental Ehrlichia canis infection in dogs were studied. Four dogs were inoculated with E canis and four were used as uninfected controls. After a 10-14-day incubation period, infected dogs developed pyrexia up to 41 degreesC for 6-8 days. Antibody titers to E. canis antigen were demonstrable in all inoculated dogs at 30 days post-infection. Necropsy of infected animals revealed pale mucous membranes, generalized lymphadenopathy, splenomegaly, edema and ascites. Microcopically, the main lesions were: lymphoreticular hyperplasia in cortical areas of lymph nodes and spleenic white pulp, periportal accumulation of mononuclear cells and centrolobular fatty degeneration of the liver. Kidneys presented with glomerulonephritis characterized by interstitial, mononuclear infiltration. Immunophenotyping of lymphocytes from lymph nodes and spleen sections displayed alterations in IgG, IgM, CD3+ and CD8+ cells population in infected dogs. (C) 2003 Elsevier B.V. All rights reserved.

Pigeons (Columba livia) are a suitable experimental model for Neospora caninum infection in birds

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Advances in Peritoneal Dialysis in Acute Kidney Injury

Peritoneal dialysis (PD) is a simple, safe, cheap, and efficient renal replacement therapy method. It can correct metabolic disorders and fluid overload in acute kidney injury (AKI) patients both in and out of the intensive care unit. Use of PD in AKI is enhanced by placement of a Tenckhoff catheter, which can be safely accomplished at the bedside. Some PD modalities, such as high-volume PD and continuous-flow PD, can provide dialysis doses and efficiency comparable to extracorporeal blood purification methods. PD is particularly suitable for neonates, children, and patients with refractory heart failure or who are otherwise hemodynamically unstable. PD should be considered in situations where systemic anticoagulation and/or vascular access are problematic. PD is limited by a lower efficiency that may produce inadequate renal replacement in larger and/or severely hypercatabolic patients. Fluid removal can be unpredictable, there is a risk of infection, and possible issues with mechanical ventilation. In this article, we discuss the use of PD in AKI, with emphasis on recent advances. Copyright (c) 2012 S. Karger AG, Basel

Analysis of the expression of toll-like receptors 2 and 4 and cytokine production during experimental Leishmania chagasi infection

Toll-like receptors (TLRs) recognise pathogen-derived molecules and influence immunity to control parasite infections. This study aimed to evaluate the mRNA expression of TLRs 2 and 4, the expression and production of the cytokines interleukin (IL)-12, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, IL-17, IL-10 and transforming growth factor (TGF)-β and the production of nitric oxide (NO) in the spleen of mice infected with Leishmania chagasi. It also aimed to evaluate any correlations between mRNA expression TLR2 and 4 and cytokines and NO production. Infection resulted in increased TLR2-4, IL-17, TNF-α and TGF-β mRNA expression during early infection, with decreased expression during late infection correlating with parasite load. IFN-γ and IL-12 mRNA expression decreased at the peak of parasitism. IL-10 mRNA expression increased throughout the entire time period analysed. Although TGF-β, TNF-α and IL-17 were highly produced during the initial phase of infection, IFN-γ and IL-12 exhibited high production during the final phase of infection. IL-10 and NO showed increased production throughout the evaluated time period. In the acute phase of infection, there was a positive correlation between TLR2-4, TNF-α, IL-17, NO, IL-10 and TGF-β expression and parasite load. During the chronic phase of infection, there was a positive correlation between TLR2-4, TNF-α, IL-17 and TGF-β expression and parasite load. Our data suggest that infection by L. chagasi resulted in modulation of TLRs 2 and 4 and cytokines.

Acute bacterial cystitis does not cause deoxyribonucleic acid damage detectable by the alkaline comet assay in urothelial cells of dogs

Considering the high incidence of dogs with acute bacterial cystitis (BC) and the relationship among inflammation, genotoxicity, and carcinogenesis, we conducted a case-control study comparing the frequency of deoxyribonucleic acid (DNA) lesions assessed by the comet assay between disease-free animals (13 males and 13 females) and cytology-confirmed cases of acute BC (12 males and 12 females), which was mainly caused by Staphylococcus sp. (40%) and Escherichia coli (35%). The results show no increase in DNA damage in cells obtained by bladder washings and no influence of age, sex, and breed due to acute BC. In conclusion, DNA damage was seemingly not associated with the infection by specific bacteria.

Acute shortening and subsequent lengthening of the radius and ulna for the treatment of an infected nonunion in a dog

A 3-year-old, male crossbred dog with osteomyelitis of the radius and ulna was treated using Ilizarov's method. Two centimeters of infected bone was resected, then acute bone shortening and subsequent lengthening of a healthy bone site were performed. The infection was eradicated, but a residual leg-length discrepancy was present.