Papers by Juliano Romanzini
PLOS Neglected Tropical Diseases, 2013
<p>Identification of <i>S. mansoni</i> eggs by the methods of Kato-Katz and Hel... more <p>Identification of <i>S. mansoni</i> eggs by the methods of Kato-Katz and Helmintex in samples from two infected individuals from a new focus of intestinal schistosomiasis in Porto Alegre, southern Brazil.</p
Angiostrongylus cantonensis foi descrito, em 1933, por Chen, em Canton, na China, como sendo um n... more Angiostrongylus cantonensis foi descrito, em 1933, por Chen, em Canton, na China, como sendo um nematódeo de pulmões de ratos. Este parasita, endêmico na Ásia e no pacífico tem como hospedeiro intermediário a Biomphalaria glabrata e, definitivo o Rattus norvergicus. Pode parasitar acidentalmente o homem causando-lhe meningite eosinofílica. O objetivo deste trabalho foi realizar um estudo inicial do proteoma de A. cantonensis durante seu desenvolvimento e maturação em R. norvergicus. Cinco grupos de quatro ratos foram inoculados com larvas de terceiro estágio (forma infectante do parasita). Os grupos foram sacrificados em períodos distintos: 15, 21, 28, 35 e 42 dias após a infecção para a retirada dos vermes. Os nematódeos foram reduzidos a pó para solubilização, desnaturação e redução das proteínas. Para os ensaios proteômicos se utilizou a técnica de Eletroforese Bidimensional. Fitas de gradiente de pH imobilizado foram reidratadas com o extrato protéico dos parasitas para proceder a primeira dimensão. Estas fitas foram submetidas à determinada voltagem. Para a segunda dimensão, cada IPG foi tratada com tampão equilibrador para preservar o estado das proteínas e evitar a reoxidação durante a eletroforese. Executou-se em géis de poliacrilamida 12% contendo SDS a corrida eletroforética de todas as fitas. A avaliação dos géis foi feita com base nas imagens obtidas a partir do programa PDQuest (BioRad). Os resultados permitem dizer que há variação nos pesos moleculares e no número de proteínas expressas durante o desenvolvimento do parasita. Algumas proteínas se mantiveram em todo ciclo, representam, por isso, um importante alvo para a identificação de componentes antigênicos específicos da fase aguda da infecção e, portanto, de utilidade diagnóstica. (CNPq).
Memórias do Instituto Oswaldo Cruz, 2012
The diagnosis of schistosomiasis is problematic in low-intensity transmission areas because paras... more The diagnosis of schistosomiasis is problematic in low-intensity transmission areas because parasitological methods lack sensitivity and molecular methods are neither widely available nor extensively validated. Helmintex is a method for isolating eggs from large faecal samples. We report preliminary results of a comparative evaluation of the Helmintex and Kato-Katz (KK) methods for the diagnosis of schistosomiasis in a low-intensity transmission area in Bandeirantes, Paraná, southern Brazil. Eggs were detected by both methods in seven patients, whereas only Helmintex yielded positive results in four individuals. The results confirm the previously demonstrated higher sensitivity of the Helmintex method compared with the KK method.
Memórias do Instituto Oswaldo Cruz, 2007
Memorias Do Instituto Oswaldo Cruz, Feb 1, 2007
Parasitology International, Dec 1, 2013
Parasitological methods for the evaluation of schistosomiasis tend to be limited when parasitic b... more Parasitological methods for the evaluation of schistosomiasis tend to be limited when parasitic burdens are low, which is a major characteristic of low intensity transmission areas. While the hatching test (HT) method has been considered to be "very sensitive", reports of its capacity to detect low numbers of eggs remain scarce in the published literature. Our main hypothesis is that HT has limitations and cannot be recommended for diagnosing light infections or as a control of cure. Hence, this study aims to describe the performance of HT in detail, with respect to seeding experiments for egg numbers in the range of 4 to 24 eggs per gram (epg) of feces. Different numbers of eggs of Schistosoma mansoni were seeded in normal human feces. The first set of experiments evaluated the amount of feces (higher than 0.5 g prevented hatching), the proximity of the light source (50 cm was preferred), and the observation time required for the detection of miracidia (more than 3 h did not add to sensitivity). HT was subsequently performed with 12, 10, 8, 6, 4, and 2 eggs in 0.5 g of feces. The final set of experiments was performed to analyze the initial filtration step, in which surgical gauze versus a 500 μm nylon mesh was compared and demonstrated losses of eggs that occurred with washing and gauze (better with nylon) sieving steps. The proposed method was found to produce 100% positivity for up to 12 epg, with a sharp decrease to 33% for 8 epg and less. In conclusion, HT is not recommended for diagnosing intestinal schistosomiasis in populations with light infections, considering the complexity of the procedure and its lack of effectiveness with fecal amounts higher than 0.5 g even at optimized conditions.
<p>Percentage of <i>S. mansoni</i> eggs recovered in supernatant (SN) and pelle... more <p>Percentage of <i>S. mansoni</i> eggs recovered in supernatant (SN) and pellet (SD) after seeding experiments with different concentrations of biotinilated lectins and paramagnetic beads covered with streptavidin.</p
<p>(*) nd: not done</p
<p>For every of three experiments, there was a negative control: eggs and beads without lec... more <p>For every of three experiments, there was a negative control: eggs and beads without lectins.</p><p><i>Triticum vulgaris</i> (Tv); <i>Concavalim A</i> (Ca); <i>Ulex europeaus</i> (Ue); <i>Arachis hypogaea</i> (Ah); <i>Lycopersicum esculentum</i> (Le)</p
<p>A preparation resulting from the incubation of eggs with biotinilated lectins and intera... more <p>A preparation resulting from the incubation of eggs with biotinilated lectins and interaction with magnetic beads covered with streptavidin was also included as a positive control.</p
Parasitology International, 2013
Parasitological methods for the evaluation of schistosomiasis tend to be limited when parasitic b... more Parasitological methods for the evaluation of schistosomiasis tend to be limited when parasitic burdens are low, which is a major characteristic of low intensity transmission areas. While the hatching test (HT) method has been considered to be "very sensitive", reports of its capacity to detect low numbers of eggs remain scarce in the published literature. Our main hypothesis is that HT has limitations and cannot be recommended for diagnosing light infections or as a control of cure. Hence, this study aims to describe the performance of HT in detail, with respect to seeding experiments for egg numbers in the range of 4 to 24 eggs per gram (epg) of feces. Different numbers of eggs of Schistosoma mansoni were seeded in normal human feces. The first set of experiments evaluated the amount of feces (higher than 0.5 g prevented hatching), the proximity of the light source (50 cm was preferred), and the observation time required for the detection of miracidia (more than 3 h did not add to sensitivity). HT was subsequently performed with 12, 10, 8, 6, 4, and 2 eggs in 0.5 g of feces. The final set of experiments was performed to analyze the initial filtration step, in which surgical gauze versus a 500 μm nylon mesh was compared and demonstrated losses of eggs that occurred with washing and gauze (better with nylon) sieving steps. The proposed method was found to produce 100% positivity for up to 12 epg, with a sharp decrease to 33% for 8 epg and less. In conclusion, HT is not recommended for diagnosing intestinal schistosomiasis in populations with light infections, considering the complexity of the procedure and its lack of effectiveness with fecal amounts higher than 0.5 g even at optimized conditions.
PLOS Neglected Tropical Diseases, Nov 14, 2007
Background: Diagnosis of intestinal schistosomiasis in low endemic areas is a problem because oft... more Background: Diagnosis of intestinal schistosomiasis in low endemic areas is a problem because often control measures have reduced egg burdens in feces to below the detection limits of classical coproparasitological methods. Evaluation of molecular methods is hindered by the absence of an established standard with maximum sensitivity and specificity. One strategy to optimize method performance, where eggs are rare events, is to examine large amounts of feces. A novel diagnostic method for isolation of Schistosoma mansoni eggs in feces, and an initial evaluation of its performance is reported here. Methodology/Principal Findings: Known amounts of S. mansoni eggs were seeded into 30 g of normal human feces and subjected to a sequence of spontaneous sedimentation, sieving, Ritchie method, incubation and isolation through interaction with paramagnetic beads. Preliminary tests demonstrated the efficacy of lectins as ligands, but they also indicated that the paramagnetic beads alone were sufficient to isolate the eggs under a magnetic field through an unknown mechanism. Eggs were identified by microscopic inspection, with a sensitivity of 100% at 1.3 eggs per gram of feces (epg). Sensitivity gradually decreased to 25% at a concentration of 0.1 epg. In a preliminary application of the new method to the investigation of a recently established focus in southern Brazil, approximately 3 times more eggs were detected than with the thick-smear Kato-Katz method. Conclusions/Significance: The novel S. mansoni detection method may significantly improve diagnosis of infections with low burdens in areas of recent introduction of the parasite, areas under successful control of transmission, or in infected travelers. It may also improve the evaluation of new treatments and vaccines.
PLoS Neglected Tropical Diseases, 2007
Background: Diagnosis of intestinal schistosomiasis in low endemic areas is a problem because oft... more Background: Diagnosis of intestinal schistosomiasis in low endemic areas is a problem because often control measures have reduced egg burdens in feces to below the detection limits of classical coproparasitological methods. Evaluation of molecular methods is hindered by the absence of an established standard with maximum sensitivity and specificity. One strategy to optimize method performance, where eggs are rare events, is to examine large amounts of feces. A novel diagnostic method for isolation of Schistosoma mansoni eggs in feces, and an initial evaluation of its performance is reported here. Methodology/Principal Findings: Known amounts of S. mansoni eggs were seeded into 30 g of normal human feces and subjected to a sequence of spontaneous sedimentation, sieving, Ritchie method, incubation and isolation through interaction with paramagnetic beads. Preliminary tests demonstrated the efficacy of lectins as ligands, but they also indicated that the paramagnetic beads alone were sufficient to isolate the eggs under a magnetic field through an unknown mechanism. Eggs were identified by microscopic inspection, with a sensitivity of 100% at 1.3 eggs per gram of feces (epg). Sensitivity gradually decreased to 25% at a concentration of 0.1 epg. In a preliminary application of the new method to the investigation of a recently established focus in southern Brazil, approximately 3 times more eggs were detected than with the thick-smear Kato-Katz method. Conclusions/Significance: The novel S. mansoni detection method may significantly improve diagnosis of infections with low burdens in areas of recent introduction of the parasite, areas under successful control of transmission, or in infected travelers. It may also improve the evaluation of new treatments and vaccines.
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Papers by Juliano Romanzini