Laboratory-acquired Chagas disease

A laboratory technician developed fever, malaise, headache and non-tender erythematous swelling proximal to the site of accidental inoculation of his thumb, 24 days earlier, with a needle contaminated with Trypanosoma cruzi. Findings included a characteristic rash, remarkable fever, relative bradycardia and leukopaenia--T lymphopaenia with maintenance of a normal helper/suppressor ratio. Trypanosomes were not detected in blood concentrates or in biopsies of an enlarged lymph node and a skin lesion. T. cruzi antibody was first detected 33 days after the laboratory accident, when parasites were first isolated. Therapy with nifurtimox was well tolerated and the patient's serology became negative 9 months after the accident.     

Neutrophil extracellular traps regulate ischemic stroke brain injury

Ischemic stroke prompts a strong inflammatory response, which is associated with exacerbated outcomes. In this study, we investigated mechanistic regulators of neutrophil extracellular trap (NET) formation in stroke and whether they contribute to stroke outcomes. NET-forming neutrophils were found throughout brain tissue of ischemic stroke patients, and elevated plasma NET biomarkers correlated with worse stroke outcomes. Additionally, we observed increased plasma and platelet surface–expressed high-mobility group box 1 (HMGB1) in stroke patients. Mechanistically, platelets were identified as the critical source of HMGB1 that caused NETs in the acute phase of stroke. Depletion of platelets or platelet-specific knockout of HMGB1 significantly reduced plasma HMGB1 and NET levels after stroke, and greatly improved stroke outcomes. We subsequently investigated the therapeutic potential of neonatal NET-inhibitory factor (nNIF) in stroke. Mice treated with nNIF had smaller brain infarcts, improved long-term neurological and motor function, and enhanced survival after stroke. nNIF specifically blocked NET formation without affecting neutrophil recruitment after stroke. Importantly, nNIF also improved stroke outcomes in diabetic and aged mice and was still effective when given 1 hour after stroke onset. These results support a pathological role for NETs in ischemic stroke and warrant further investigation of nNIF for stroke therapy.     

Genetic Characterization of a New HIV-1 Sub-Subtype A in Cabo Verde,Denominated A8

Previous molecular characterization of Human immunodeficiency virus (HIV-1) samples from Cabo Verde pointed out a vast HIV-1 pol diversity, with several subtypes and recombinant forms, being 5.2% classified as AU-pol. Thus, the aim of the present study was to improve the characterization of these AU sequences. The genomic DNA of seven HIV-1 AU pol-infected individuals were submitted to four overlapping nested-PCR fragments aiming to compose the full-length HIV-1 genome. The final classification was based on phylogenetic trees that were generated using the maximum likelihood and bootscan analysis. The genetic distances were calculated using Mega 7.0 software. Complete genome amplification was possible for two samples, and partial genomes were obtained for the other five. These two samples grouped together with a high support value, in a separate branch from the other sub-subtypes A and CRF26_A5U. No recombination was verified at bootscan, leading to the classification of a new sub-subtype A. The intragroup genetic distance from the new sub-subtype A at a complete genome was 5.2%, and the intergroup genetic varied from 8.1% to 19.0% in the analyzed fragments. Our study describes a new HIV-1 sub-subtype A and highlights the importance of continued molecular surveillance studies, mainly in countries with high HIV molecular diversity.     

Molecular cloning, expression and immunological properties of LiD1, a protein from the dermonecrotic family of Loxosceles intermedia spider venom.

The present report describes the identification and molecular characterization of LiD1, a protein expressed in the venom gland of the brown spider Loxosceles intermedia. LiD1 belongs to a family of proteins with dermonecrotic activity and members of this family have been found in spiders from the genus Loxosceles. The necrotic lesions caused by this group of proteins may lead to serious socio-economic problems such as surgical tissue reconstitution and even patient death. LiD1 was cloned using a cDNA library constructed from the venom gland of L. intermedia and antibodies against proteins with dermonecrotic activity isolated from the crude venom of this spider. The amino acid sequence deduced from the cDNA revealed a mature protein of approximately 31 kDa, with a pI of 7.37. The cDNA also revealed the existence of a signal peptide, a propeptide and also an untranslated 3′ region with 218 nucleotides. LiD1 was expressed as a protein fused with β-galactoside protein using the vector pBK-CMV, resulting in the recombinant protein recLiD1 with important immunological properties. recLiD1 was strongly recognised by anti-dermonecrotic antibodies and was also able to generate reactive antibodies against native dermonecrotic proteins isolated from the venom of L. intermedia.     

Erythropoietin (Epo), protein and iron supplementation and the prevention of anaemia of prematurity: effects on serum immunoreactive Epo, growth and protein and iron metabolism

The effect of recombinant human (r-Hu) erythropoietin (Epo) (300 IU/kg per week for 4 weeks) was studied in healthy preterm infants ( n = 14) fed human milk with additional milk protein and high doses of iron. The controls ( n = 15) were in themselves a study group and were used to follow the natural course of anaemia of prematurity on such nutrition. Serum immunoreactive Epo (SiEpo) increased significantly 24h after r-HuEpo injections (range 36 to > 128 mU/ml) and remained at these levels throughout the treatment period. r-HuEpo in such moderate doses kept haemoglobin above 11 g/dl. Bodyweight gain, protein and iron parameters indicated adequacy of dietary protein and iron. In controls, siEpo increased during the first weeks after nutritional supplementation, with a concommitant rise in reticulocyte count. At age 3 weeks, despite low siEpo levels, reticulocyte counts indicated active erythropoiesis. Following further moderate increases in siEpo, the reticulocyte count increased to high levels (7%). The reticulocyte response suggests that erythropoiesis in preterm infants is less dependent upon Epo levels than in adults.     

Toxoplasma antigens recognized by naturally occurring human antibodies.

Sera of most adults have high agglutination test titers to Toxoplasma gondii whether or not the adults have other serological evidence of the infection. This finding has been attributed to the presence of naturally occurring antibodies to T. gondii. Consistent with this observation, we have recently noted that protein blots (PB) of sera of individuals not previously infected with T. gondii had immunoglobulin G (IgG) and IgM antibodies to antigens of the parasite. To further define the antigens recognized by these naturally occurring antibodies, we studied PB of sera of 44 adults and 9 children who had no serological evidence of the infection. Multiple antigens of T. gondii with molecular weights of 15,000 to greater than 205,000 were recognized by IgG and IgM natural antibodies of each of the sera. Although a relatively consistent pattern was noted on the IgM PB of the sera of the adults in the molecular weight range of 48,000 to 85,000, greater heterogeneity was noted on the IgG PB. The most common bands noted on the latter were of approximately 30,000 and 92,000 molecular weight. All of the PB obtained with the serial sera collected at yearly intervals from the children revealed bands; in some cases, new bands had appeared with time, and in others the pattern was constant. In children older than 8 years, the patterns of the PB were similar to those noted in PB of sera of the adults.     

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