Avaliação do teste imunocromatográfico ("ICT card test") no diagnóstico da filariose em estudos populacionais

This study evaluated the whole blood immunochromatographic card test (ICT card test) in a survey performed in Northeastern Brazil. 625 people were examined by the thick blood film (TBF) and ICT card test. Residents of a non-endemic area were also tested by the whole blood card test and Og4C3. The sensitivity of the ICT card test was 94.7% overall, but lower in females than males, based on the reasonable assumption that TBF is 100% specific. However, since TBF and other methods have unknown sensitivity, the true specificity of the card test is unknown. Nevertheless, it is possible to estimate upper and lower limits for the specificity, and relate it to the prevalence of the disease. In the endemic area, the possible range of the specificity was from 72.4% to 100%. 29.6% of the card tests performed in the non-endemic area exhibited faint lines that were interpreted as positives. Characteristics of the method including high sensitivity, promptness and simplicity justify its use for screening of filariasis. However, detailed information about the correct interpretation in case of extremely faint lines is essential. Further studies designed to consider problems arising from imperfect standards are necessary, as is a sounder diagnostic definition for the card test.Este estudo avaliou o teste imunocromatográfico ("ICT card test") em inquérito de filariose realizado no município de Olinda, Brasil. 625 pessoas foram examinadas pela técnica da gota espessa (GE), e "ICT card test" (ICT). Moradores do município de Campina Grande, Paraíba, área não endêmica, foram examinados pelos testes ICT e Og4C3-ELISA, para verificação da especificidade. A sensibilidade do método foi de 94,7%. O desenho do estudo - que envolveu a acurácia do ICT e do teste de referência (GE), em todos os elementos da amostra, - e a especificidade de 100% da GE permitiram o cálculo correto da sensibilidade. Todavia, como a sensibilidade da GE é desconhecida, a especificidade do ICT é ignorada. É possível, contudo, estimar o limite superior e inferior da especificidade e relacioná-la à prevalência de doença. Na área endêmica, a especificidade do teste variou entre 72,4% e 100,0%. 29,6% dos exames pelo ICT, realizados na área não endêmica, exibiram coloração tênue, tendo sido interpretados como positivos. Algumas características do método, incluindo alta sensibilidade, rapidez e simplicidade de execução justificam sua utilização em rastreamento de áreas endêmicas. Todavia, detalhes acerca da correta interpretação dos resultados com coloração extremamente tênue, parecem de importância fundamental

Higienizando superfícies contaminadas pelo vírus Sars-Cov-2: uma proposta de ensino à luz da Modelagem Matemática/ Sanitizing surfaces contaminated by the Sars-Cov-2 virus: a teaching proposal in the light of Mathematical Modeling

O presente artigo tem como objetivo apresentar propostas de atividades no ensino de matemática para estudantes do 9º ano do Ensino Fundamental e que foram elaboradas para que o professor possa trabalhar a Modelagem Matemática como metodologia para o ensino de conteúdos matemáticos. Vale ressaltar que as atividades estão alinhadas junto às habilidades e competências propostas pela Base Nacional Comum Curricular, BNCC, e estão direcionadas a um assunto da atualidade que diz respeito a situação pandêmica causada pelo vírus Sars-Cov-2. Com isso, a partir do tratamento de dados reais, o professor poderá direcionar o aluno a tentar obter modelos matemáticos que sejam capazes de torná-los agentes do seu próprio conhecimento. Dessa forma, o estudante passa a atuar de maneira ativa, aguçando sua curiosidade ao tratar de um assunto atual que o ajudará a vivenciar uma matemática diferenciada que perpassa por assuntos como razão, proporção, geometria e até mesmo a própria educação financeira

Field evaluation of the whole blood immunochromatographic test for rapid bancroftian filariasis diagnosis in the northeast of Brazil.

This study evaluated the whole blood immunochromatographic card test (ICT card test) in a survey performed in Northeastern Brazil. 625 people were examined by the thick blood film (TBF) and ICT card test. Residents of a non-endemic area were also tested by the whole blood card test and Og4C3. The sensitivity of the ICT card test was 94.7% overall, but lower in females than males, based on the reasonable assumption that TBF is 100% specific. However, since TBF and other methods have unknown sensitivity, the true specificity of the card test is unknown. Nevertheless, it is possible to estimate upper and lower limits for the specificity, and relate it to the prevalence of the disease. In the endemic area, the possible range of the specificity was from 72.4% to 100%. 29.6% of the card tests performed in the non-endemic area exhibited faint lines that were interpreted as positives. Characteristics of the method including high sensitivity, promptness and simplicity justify its use for screening of filariasis. However, detailed information about the correct interpretation in case of extremely faint lines is essential. Further studies designed to consider problems arising from imperfect standards are necessary, as is a sounder diagnostic definition for the card test

Simplagrin, a Platelet Aggregation Inhibitor from <i>Simulium nigrimanum</i> Salivary Glands Specifically Binds to the Von Willebrand Factor Receptor in Collagen and Inhibits Carotid Thrombus Formation <i>In Vivo</i>

<div><p>Background</p><p>Among the several challenges faced by bloodsucking arthropods, the vertebrate hemostatic response against blood loss represents an important barrier to efficient blood feeding. Here we report the first inhibitor of collagen-induced platelet aggregation derived from the salivary glands of a black fly (<i>Simulium nigrimanum</i>), named Simplagrin.</p><p>Methods and Findings</p><p>Simplagrin was expressed in mammalian cells and purified by affinity-and size-exclusion chromatography. Light-scattering studies showed that Simplagrin has an elongated monomeric form with a hydrodynamic radius of 5.6 nm. Simplagrin binds to collagen (type I-VI) with high affinity (2–15 nM), and this interaction does not involve any significant conformational change as determined by circular dichroism spectroscopy. Simplagrin-collagen interaction is both entropically and enthalpically driven with a large negative ΔG, indicating that this interaction is favorable and occurs spontaneously. Simplagrin specifically inhibits von Willebrand factor interaction with collagen type III and completely blocks platelet adhesion to collagen under flow conditions at high shear rates; however, Simplagrin failed to block glycoprotein VI and Iα₂β₁ interaction to collagen. Simplagrin binds to RGQOGVMGF peptide with an affinity (K_D 11 nM) similar to that of Simplagrin for collagen. Furthermore, Simplagrin prevents laser-induced carotid thrombus formation <i>in vivo</i> without significant bleeding in mice and could be useful as an antithrombotic agent in thrombosis related disease.</p><p>Conclusion</p><p>Our results support the orthology of the Aegyptin clade in bloodsucking Nematocera and the hypothesis of a faster evolutionary rate of salivary function of proteins from blood feeding arthropods.</p></div

Effect of Simplagrin on platelet adhesion to fibrillar collagen under high shear stress.

<p>Simplagrin inhibits platelet collagen interaction under high shear stress in a dose dependent fashion. Anticoagulated whole blood from healthy patients was perfused over immobilized fibrillar collagen for 240 seconds at a shear rate of 1500⁻¹ in the presence of different doses of Simplagrin and immediately perfused with Tyrode's buffer at the same shear rate to remove loosely bound platelets. Coverslips were mounted and analyzed under bright-field microscopy. Representative results of a typical experiment (n = 6).</p

Expression of recombinant Simplagrin and biophysical analysis.

<p>(A) Recombinant Simplagrin was expressed as a secreted protein in HEK293 cells. Supernatant containing Simplagrin was concentrated and loaded onto a Ni⁺²-Hitrap column for affinity purification and further purified to homogeneity by size exclusion chromatography. Inset: Coomassie stained NuPAGE and western blot using rabbit anti-Simplagrin antibodies. (B) Circular dichroism (CD) spectroscopy analysis of Simplagrin shows that it mainly comprises α-helix (59%) followed by unordered/disorganized (29%) secondary structures. Inset shows the calculated percentages of secondary structures determined by CD analysis. (C) Analytical size exclusion chromatography shows that Simplagrin runs at a higher than expected molecular weight. (D) Hydrodynamic property of Simplagrin demonstrates its monomeric, elongated form with a hydrodynamic radius of 5.6 nm. The calculated molecular weight of Simplagrin by dynamic scattering plot was 32 kDa (blue line in the chromatogram). (E) Recombinant Simplagrin is not glycosylated in HEK293 cells. Evaluation of putative glycosylation of recombinant Simplagrin was evaluated using DeGlycoMx kit. Fifteen µg of Simplagrin or Lundep (positive control) were heat denatured and treated with an enzymatic deglycosylase mix. After three hours at 37°C, samples were electrophoresed in a NuPAGE-MES and stained with Coomassie blue. Lane 1: Lundep, 2: Lundep+DeGlycoMx, 3: Simplagrin, 4: Simplagrin+DeGlycoMx, 5: mW standard (SeeBlue Plus2 in kDa).</p

Surface plasmon resonance analysis of Simplagrin-RGQOGVMGF peptide.

<p>Kinetic and binding constants were calculated using a 1:1 interaction binding model. Experiments were carried out in triplicate.</p

Simplagrin blocks von Willebrand Factor (vWF) interaction to collagen but not GPVI to collagen.

<p>(A) In solution competition using surface plasmon resonance (SPR) shows that Simplagrin inhibits interaction of collagen and RGQOGVMGF peptide on immobilized vWF. Collagen type I (0.1 µM) or RGQOGVMGF peptide (1 µM) in the presence or absence of Simplagrin (0.2 µM) were flowed over immobilized vWF. No detectable Simplagrin-vWF binding was observed. (B) Preincubation Simplagrin with saturating concentrations of RGQOGVMGF peptide abrogates Simplagrin-collagen interaction in SPR experiments. (C) Solid-phase assay showing that Simplagrin blocks, in a dose-response manner, collagen vWF interaction. (D) Simplagrin partially blocks GPVI-collagen interaction. SPR in solution competition shows that preincubation of collagen or CRP with Simplagrin at 1∶20 or 1∶40 molar ratios only reduces the response binding of collagen to GPVI approximately 60%; however, Simplagrin fails to block CRP-GPVI interaction. This can be explained by steric hindrance of Simplagrin binding to RGQOGVMGF sequence in collagen. (E) Control experiment showing that Simplagrin does not affect convulxin-GPVI interaction. All SPR experiments were carried out in triplicate.</p

Simplagrin binds to RGQOGVMGF, the von Willebrand Factor (vWF) binding site on collagen.

<p>(A) Surface plasmon resonance binding analysis of immobilized Simplagrin with CRP (cross-linked GPO₁₀), vWFpep (cross linked RGQOGVMGF), Iα₂β₁pep (cross-linked GFOGER) and Col-I (collagen type I). (B) Solid phase binding assay shows that Simplagrin binds in a dose response manner to wells coated with RGQOGVMGF peptides. Binding was detected using rabbit anti-Simplagrin antibodies. (C) Kinetic analysis showing that Simplagrin displays high affinity (K_D 11.1±0.59 nM) for RGQOGVMGF peptide. Analyte concentration ranging from 1–500 nM of RGQOGVMGF were flowed over immobilized Simplagrin at 30 µL/minute for 180 seconds, and the complex dissociation was monitored for 600 seconds before regeneration of the sensor surface. A global 1∶1 reaction model was used to calculate kinetic parameters.</p