Pediatric cerebral sinus venous thrombosis: clinical characterization of a Portuguese cohort.

INTRODUCTION: Pediatric cerebral sinus venous thrombosis (CSVT) is a rare entity. Risk factors differ from the adults, and treatment is not consensual. With this work, we aimed to characterize a pediatric cohort from two Portuguese tertiary centers. METHODS: All patients under 18 years old with confirmed CSVT admitted between 2006 and 2019 were retrospectively included. Demographics, clinical presentation, workup, and follow-up were evaluated. RESULTS: Fifty-three patients were included, 29 were male (54.7%). Median age was 5 years (IQR 11.08, range 0-17 years old). Headache, seizures and impairment of consciousness were the most frequent manifestations. A risk factor was identified in 90.6% (n = 48), mostly infections (43.8%; n = 21). CNS complications were comprised of hemorrhage, venous infarction, hydrocephalus and edema. Treatment included anticoagulation in 36 patients (67.9%), and there were no recurrences on follow-up. Prognosis was favorable, with most patients presenting no or only slight disability comparing to same age and sex children, on the follow-up. DISCUSSION: In this cohort, impairment of consciousness was the most frequent clinical presentation and infections were the most frequent risk factors. The outcome was mainly favorable, with most patients presenting none or mild disability and without recurrences on follow-up. Studies are needed to define the criteria for anticoagulation and its recommended duration in children.

Broadband Microwave Electrical Transport Spectroscopy for Two-Dimensional Material Systems.

In recent years, interesting materials have emerged which are only available as µm-scale flakes, and whose novel physics might be better understood through broadband microwave spectroscopy; examples include twisted bilayer graphene [Y. Cao S. Fang, K. Watanabe, T. Taniguchi, E. Kaxiras and P. Jarillo-Herrero Nature 556, 43 (2018).], 2D materials in which many-body phases are observed [S. Chen R. Ribeiro-Palau, K. Yang, T. Taniguchi, J. Hone, M. O. Goerbig and C. R. Dean Physical Review Letters 122¸ 026802 (2019)], and artificial lattices for analog quantum simulations [J. Salfi J. A. Mol, R. Rahman, G. Klimeck, M. Y. Simmons, L. C. L. Hollenberg and S. Rogge Nature Communications 7, 1 (2016)]. Most previous techniques are unfortunately not sensitive for flakes below mm lateral sizes. We propose a simple technique which does not require sophisticated sample preparation nor Ohmic contact and show through theory and simulations that one will be able to qualitatively measure spectral features of interest, and quantitatively measure the frequency-dependent complex conductivity.

Turn of the decade: versatility of 2D hexagonal boron nitride.

The era of two-dimensional (2D) materials, in its current form, truly began at the time that graphene was first isolated just over 15 years ago. Shortly thereafter, the use of 2D hexagonal boron nitride (h-BN) had expanded in popularity, with use of the thin isolator permeating a significant number of fields in condensed matter and beyond. Due to the impractical nature of cataloguing every use or research pursuit, this review will cover ground in the following three subtopics relevant to this versatile material: growth, electrical measurements, and applications in optics and photonics. Through understanding how the material has been utilized, one may anticipate some of the exciting directions made possible by the research conducted up through the turn of this decade.

Analytical determination of atypical quantized resistances in graphene p-n junctions.

A mathematical approach is introduced for predicting quantized resistances in graphene p-n junction devices that utilize more than a single entry and exit point for electron flow. Depending on the configuration of an arbitrary number of terminals, electrical measurements yield nonconventional, fractional multiples of the typical quantized Hall resistance at the v = 2 plateau (R H ≈ 12906 Ω) and take the form: a b R H . This theoretical formulation is independent of material, and applications to other material systems that exhibit quantum Hall behaviors are to be expected. Furthermore, this formulation is supported with experimental data from graphene devices with multiple source and drain terminals.

Analysing quantized resistance behaviour in graphene Corbino p-n junction devices.

Just a few of the promising applications of graphene Corbino pnJ devices include two-dimensional Dirac fermion microscopes, custom programmable quantized resistors, and mesoscopic valley filters. In some cases, device scalability is crucial, as seen in fields like resistance metrology, where graphene devices are required to accommodate currents of the order 100 µA to be compatible with existing infrastructure. However, fabrication of these devices still poses many difficulties. In this work, unusual quantized resistances are observed in epitaxial graphene Corbino p-n junction devices held at the ν = 2 plateau (R H ≈ 12906 Ω) and agree with numerical simulations performed with the LTspice circuit simulator. The formulae describing experimental and simulated data are empirically derived for generalized placement of up to three current terminals and accurately reflects observed partial edge channel cancellation. These results support the use of ultraviolet lithography as a way to scale up graphene-based devices with suitably narrow junctions that could be applied in a variety of subfields.

[Epileptic Encephalopathies of Childhood: The New Paradigm of Genetic Diagnosis]. / Encefalopatias Epilépticas Infantis: O Novo Paradigma do Diagnóstico Genético.

INTRODUCTION: Epileptic encephalopathies of childhood are characterized by early seizure-onset and adverse neurological outcomes. The development of new genetic techniques has allowed an exponential identification of the genes that are involved. Over the last years, we have observed a revolution in the diagnostic paradigm. However, there are no international guidelines regarding the diagnosis of genetic epileptic encephalopathies. We aim to discuss the current knowledge about the genetic architecture of epileptic encephalopathies of childhood. MATERIAL AND METHODS: review of the literature about infantile epileptic encephalopathies and the genetic tests currently available. A systematic approach and a diagnostic algorithm to use in clinical practice were proposed. RESULTS: Initially the patient's phenotype should be determined based on the seizure type, electroencephalogram pattern and neuroimaging. Patients with unclear etiology after brain magnetic resonance imaging should undergo an appropriate metabolic investigation to promptly exclude treatable conditions. Further studies should also include other genetic causes, mainly if associated with particular phenotypic features. Chromosomal microarray analysis should be firstly considered, particularly if dysmorphic or polymalformative abnormalities are present. If this is negative and/or there are no physical features, the next step should be next-generation sequencing multigene panels or whole-exome sequencing. Single gene study should only be considered when the patient's phenotype is highly suggestive of a specific syndrome. CONCLUSION: The revolution of the genetic knowledge about epileptic encephalopathies of childhood has led to a complex diagnostic approach. This new paradigm poses significant implications in genetic counselling, treatment and prognosis.

Introdução: As encefalopatias epilépticas da infância constituem um grupo de patologias de início precoce e prognóstico neurológico reservado. O desenvolvimento das novas técnicas de estudo genético foi responsável pela identificação de novos genes implicados. Nos últimos anos, assistimos a uma revolução no seu paradigma diagnóstico. Contudo, actualmente não existem recomendações internacionais consensuais sobre a abordagem à investigação das encefalopatias epilépticas genéticas. Pretendemos discutir o conhecimento actual sobre a arquitectura genética das encefalopatias epilépticas infantis.Material e Métodos: Realizou-se uma revisão da literatura das encefalopatias epilépticas infantis genéticas e estudos utilizados no seu diagnóstico. Propomos uma abordagem sistematizada através de um algoritmo diagnóstico a utilizar na prática clínica.Resultados: Inicialmente deve-se determinar o fenótipo do doente com base no tipo de crises, padrão electroencefalográfico e neuroimagem. Nos doentes sem etiologia após resultados de ressonância magnética cranioencefálica, deve-se realizar estudo metabólico apropriado para o diagnóstico prioritário de doenças metabólicas tratáveis. A investigação de outras causas genéticas deve ser considerada, sobretudo perante características fenotípicas sugestivas. Primeiro deve-se realizar a análise de microarray cromossómico, principalmente se existirem alterações dismórficas ou polimalformativas. Se esta for negativa e/ou não existirem elementos físicos distintivos, o próximo passo deve ser realizar os painéis multigénicos ou sequenciação de exoma. Os estudos dirigidos do gene devem ser reservados para quando o fenótipo é indicativo de uma síndrome específica.Conclusão: A marcha diagnóstica das encefalopatias epilépticas tornou-se complexa com a expansão de conhecimentos genéticos. Este novo paradigma apresenta implicações terapêuticas, prognósticas e de aconselhamento familiar.

Extensive linear scleroderma en coup de sabre with exertion-induced hemiplegic migraine.

We report the case of a 9-year-old girl with linear scleroderma en coup de sabre (LSCS) who developed progressive white matter involvement, presenting as intractable hemiplegic migraine-like attacks induced by exercise. After a period of severely aggressive course, clinical and radiological stabilization was achieved under immunosuppressant treatment. Intrathecal synthesis of IgG and lymphocytic pleocytosis provided indirect evidence of a chronic inflammatory process of the central nervous system. We discuss the possible immunopathogenic mechanisms responsible for the neurocutaneous involvement in LSCS, favouring the hypothesis of an autoimmune and inflammatory vasculopathy. The singular occurrence of hemiplegic migraine triggered by exertion add further insight to the currently unknown pathogenesis of scleroderma disorder. In addition, we highlight the importance of intensive immunosuppression approaches in selected cases, contrasting with the classic benign course of LCSC.

Síndrome de hemiconvulsión-hemiplejía-epilepsia: caso clínico y uso de dextrometorfano / Hemiconvulsion-hemiplegia-epilepsy syndrome: case report and use of dextromethorphan

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Predictores pronósticos de desarrollo neurológico en recién nacidos a término con crisis neonatales / Neurodevelopmental outcome predictors of term newborns with neonatal seizures

Introducción: El peso específico de las crisis neonatales en el pronóstico neurológico de recién nacidos a término no se conoce bien, por lo que el objetivo del estudio era describir predictores pronósticos en crisis neonatales. Sujetos y métodos: Estudio observacional prospectivo de recién nacidos a término con crisis clínicas en un centro terciario (2009-2018). Pronóstico adverso se definió como muerte, retraso global del desarrollo, parálisis cerebral o epilepsia. Se analizaron las características perinatales, la etiología, los hallazgos electroencefalográficos, la neuroimagen y los tratamientos antiepilépticos siguiendo un modelo de regresión logística. Resultados: Se incluyó a un total de 102 recién nacidos (52 de los cuales tenían desarrollo normal). Se registraron 12 fallecimientos. En el grupo de supervivientes, 38 niños tuvieron un pronóstico desfavorable (28 con retraso global del desarrollo, 27 con parálisis cerebral, 21 con epilepsia). De las variables pronósticas identificadas en el análisis univariante, las complicaciones perinatales, el inicio de las crisis en el primer día de vida, la actividad basal anormal moderada a grave, un patrón anormal en el electroencefalograma de amplitud integrada y la respuesta al tratamiento continuaron mostrándose como independientemente asociadas a pronóstico adverso después de aplicar un modelo de regresión logística. Conclusiones: Existen datos contradictorios sobre marcadores subrogados en crisis neonatales. Aparte de confirmar el valor predictivo de variables previamente descritas, se halló que la monitorización con electroencefalograma de amplitud integrada constituye una prometedora herramienta diagnóstica. En el futuro, se debería extender su utilización en el abordaje de estos pacientes, lo que sería de vital importancia para un diagnóstico y un tratamiento precoces

Introduction: The concrete burden of neonatal seizures in neurodevelopmental outcome of term newborns is still unknown in literature. The aim of this study was to describe prognostic predictors in neonatal seizures. Subjects and methods: Observational prospective study of term neonates with clinical seizures from a tertiary center (2009-2018). Adverse outcome was determined as death, global developmental delay, cerebral palsy or epilepsy. Perinatal characteristics, etiology, electrographic features, neuroimaging and antiepileptic treatment were analyzed in a logistic regression model. Results: A total of 102 newborns were included (52 infants with normal outcome). Twelve fatalities were registered. In the survival group, 38 children had an adverse outcome (28 global developmental delay, 27 cerebral palsy, 21 epilepsy). From the prognostic variables identified in univariate analysis, perinatal complications, seizure onset in the first day of life, moderate to severe abnormal background activity, abnormal amplitude-integrated EEG pattern, and treatment response remained independently associated with adverse outcome after a logistic regression model. Conclusions: There is conflicting data about surrogate markers in neonatal seizures. Aside from confirming the predictive value of previously described variables, we observed that amplitude-integrated EEG monitoring is a forthcoming prognostic tool. Future approaches may include a wider use of amplitude-integrated EEG monitoring, being crucial for timely seizure identification and prompt treatment

Variante faringo-cérvico-braquial da síndrome de Guillain-Barré:uma causa rara de disfunção bulbar aguda em crianças / Pharyngeal-cervical-brachial variant of Guillain-Barré syndrome:a rare cause of acute bulbar dysfunction in children

Aims: To report a case of pharyngeal-cervical-brachial variant of Guillain-Barré syndrome, which is characterized by rapidly progressivebulbar palsy with upper limb, neck and oropharyngeal involvement. It is a rare disorder in childhood and most cases have been described inadolescents.Case Description: A seven year-old-boy presented with dysarthria, hoarseness, dysphagia, facial diplegia and bilateral progressive upperlimb weakness. These symptoms started two weeks after a gastrointestinal infection. Nerve conduction studies were compatible with an acutedemyelinating polyneuropathy in the upper extremities. Anti-ganglioside antibodies in the serum (anti-GT1a, GD1a, GQ1b) were positiveand Campylobacter jejuni was isolated from stools. The patient was treated with intravenous immunoglobulin and needed ventilatory supportduring the first 12 days of admission. He was discharged at day 15 showing improvement of his neurological deficits. He fully recovered aftereleven months of follow-up.Conclusions: Although pharyngeal-cervical-brachial variant of Guillain-Barré syndrome is uncommon in children, it should be consideredin a child with acute bulbar dysfunction because a timely diagnosis allows the early institution of therapeutic measures that can be lifesaving.

Objetivos: Relatar um caso da variante faringo-cervico-braquial da síndrome de Guillain-Barré, que se caracteriza por paralisia bulbarrapidamente progressiva com envolvimento dos membros superiores, pescoço e região orofaríngea. É um diagnóstico raro na criança, ocorrendoa maioria dos casos em adolescentes.Descrição do Caso: Um menino de sete anos de idade iniciou com queixas de disartria, disfonia, disfagia, diplegia facial e fraqueza muscularprogressiva dos membros superiores. Estes sintomas surgiram duas semanas após uma infeção gastrointestinal. Os estudos eletrofisiológicosforam compatíveis com polineuropatia aguda desmielinizante nos membros superiores. Os anticorpos anti-gangliosídeo no plasma(anti-GT1a, GD1a, GQ1b) foram positivos e Campylobacter jejuni foi isolado nas fezes. O paciente foi tratado com imunoglobulina endovenosae necessitou de suporte ventilatório durante os primeiros 12 dias. Teve alta no 15º dia com melhora dos sintomas neurológicos. Recuperou-setotalmente após 11 meses de seguimento.Conclusões: Apesar da variante faringo-cervico-braquial ser pouco frequente em idade pediátrica, é um diagnóstico que deve ser consideradoperante uma criança com disfunção bulbar aguda, pois a identificação precoce permite instituir rapidamente medidas terapêuticas que podemevitar a morte.

Rett syndrome with and without detected MECP2 mutations: an attempt to redefine phenotypes.

BACKGROUND: The diagnosis of Rett syndrome (RTT) is based on a set of clinical criteria, irrespective of mutation status. The aims of this study were (1) to define the clinical differences existing between patients with Rett syndrome with (Group I) and without a MECP2 mutation (Group II), and (2) to characterize the phenotypes associated with the more common MECP2 mutations. PATIENTS AND METHODS: We analyzed 87 patients fulfilling the clinical criteria for RTT. All were observed and videotaped by the same paediatric neurologist. Seven common mutations were considered separately, and associated clinical features analysed. RESULTS: Comparing Group I and II, we found differences concerning psychomotor development prior to onset, acquisition of propositive manipulation and language, and evolving autistic traits. Based on age at observation, we found differences in eye pointing, microcephaly, growth, number of stereotypies, rigidity, ataxia and ataxic-rigid gait, and severity score. Patients with truncating differed from those with missense mutations regarding acquisition of propositive words and independent gait, before the beginning of the disease, and microcephaly, growth, foot length, dystonia, rigidity and severity score, at the time of observation. Patients with the R168X mutation had a more severe phenotype, whereas those with R133C showed a less severe one. Patients with R294X had a hyperactive behaviour, and those with T158M seemed to be particularly ataxic and rigid. CONCLUSION: A clear regressive period (with loss of prehension and language, deceleration of growth) and the presence of more than three different stereotypies, rigidity and ataxic-rigid gait seemed to be very helpful in differentiating Group I from Group II.

Experimental Chagas' disease in orchiectomized Calomys callosus infected with the CM strain of Trypanosoma cruzi.

The incidence and progression of disorders associated with an unbalanced immune response has among many factors the gender as a contributory factor. The aims of this work were to evaluate the effects of orchiectomy and the immune response during the experimental Trypanosoma cruzi infection. Young adult, male Calomys callous were i.p. inoculated with 1 x 10(5) blood trypomastigotes of the CM strain of T. cruzi and divided in groups: Control, Sham and Castrated. Castrated group displayed significantly lower values for prostate and seminal vesicle weights indicating a drastic drop of testosterone plasmatic levels. Orchiectomized animals also displayed lesser number of blood parasites, enhanced lytic antibody percentage, splenocyte proliferation and NO concentration when compared to its sham and control counterparts, indicating that steroid gonadal ablation actually influences immune response triggering a more efficient cellular and humoral response which led animals to become more resistant against T. cruzi infection.

Influence sexual dimorphism on the persistence of blood parasites in infected Calomys callosus / Influence sexual dimorphism on the persistence of blood parasites in infected Calomys callosus

Gender has long been known to be a contributory factor in the incidence and progression of disorders associated with immune system disregulation. The aims of this experiment were to verify the influences of sexual dimorphism on the persistence of blood parasites out of

the acute phase of infection. Male and female Calomys callosus were separated and infected with two strains of Trypanosoma cruzi, and let age until 120 days. Xenogiagnostic, culture of organs and blood, histopathology and lytic antibody percentages were evaluated on late

chronic phase. Xenodiagnosis, hemoculture and lytic antibody percentages were positive from 45 until 120 days. For both strains in adrenal

and heart, amastigote burdens were present until 45 days, scarcely found on 60 days and absent on 120 days. Steroid hormones, although having a protective role, does not enable animals to get completely rid of the infection. Even without showing apparent signs

of pathological unbalance, parasite persists, hidden throughout the host’s body.

Movement disorders in Rett syndrome: an analysis of 60 patients with detected MECP2 mutation and correlation with mutation type.

Rett syndrome (RS) is one of the best human models to study movement disorders. Patients evolve from a hyperkinetic to a hypokinetic state, and a large series of abnormal movements may be observed along their lives such as stereotypies, tremor, chorea, myoclonus, ataxia, dystonia, and rigidity. The aim of this work was to analyze movement disorders in RS patients with a detected MECP2 mutation, as well as their correlation with genotype, in a clinically and genetically well-characterized sample of patients, and thus contribute to redefine the clinical profile of this disease. In this study, we included 60 patients with detected MECP2 mutations. These were categorized and grouped for analysis, according to (1) type of change (missense or truncating, including nonsense and frameshift but also large deletions) and (2) location of the mutation. Differences were found concerning the frequency of independent gait, dystonia, type of tremor, and global score severity when comparing the group of patients with missense and truncating mutations. We also found differences in the presence, distribution, severity, or type of movement disorders in the two groups of patients according to the median duration of the disease (less than 60 months; 60 months or more). We conclude that movement disorders seem to reflect the severity and rate of progression of Rett disorder, patients with truncating mutations presenting a higher rate and more severe dystonia and rigid-akinetic syndrome, when comparing groups with similar time of disease evolution.

Trypanosoma cruzi: effects of social stress in Calomys callosus a natural reservoir of infection.

Social environment can represent a major source of stress affecting cortisol and/or corticosterone levels, thereby altering the immune response. We have investigated the effects of social isolation on the development of Trypanosoma cruzi infection in female Calomys callosus, a natural reservoir of this protozoan parasite. Animals were divided in groups of five animals each. The animals of one group were kept together in a single cage. In a second group, four females were kept together in a cage with one male. In the final group, five individuals were kept isolated in private cages. The isolated animals showed body weight reduction, decreased numbers of peritoneal macrophages, lower global leucocytes counts, smaller lytic antibody percentage and a significantly higher level of blood parasites compared to the other animals. Their behavior was also altered. They were more aggressive than grouped females, or females exposed to the presence of a male. These results suggest that isolation creates a distinct social behavior in which immunity is impaired and pathogenesis is enhanced.

Influence sexual dimorphism on the persistence of blood parasites in infected Calomys callosus.

Gender has long been known to be a contributory factor in the incidence and progression of disorders associated with immune system disregulation. The aims of this experiment were to verify the influences of sexual dimorphism on the persistence of blood parasites out of the acute phase of infection. Male and female Calomys callosus were separated and infected with two strains of Trypanosoma cruzi, and let age until 120 days. Xenogiagnostic, culture of organs and blood, histopathology and lytic antibody percentages were evaluated on late chronic phase. Xenodiagnosis, hemoculture and lytic antibody percentages were positive from 45 until 120 days. For both strains in adrenal and heart, amastigote burdens were present until 45 days, scarcely found on 60 days and absent on 120 days. Steroid hormones, although having a protective role, does not enable animals to get completely rid of the infection. Even without showing apparent signs of pathological unbalance, parasites persists, hidden throughout the host's body.

Trypanosoma cruzi: plasma corticosterone after repetitive stress during the acute phase of infection.

An increased level of plasma corticosterone is one manifestation of severe environmental or physiologic stress. The stress response mediated by the hypothalamic-pituitary-adrenal axis is already known to suppress immunoglobulin production and to impair immune function, but there are few studies relating stress and plasma corticosterone to the outcome of Trypanosoma cruzi infection. In this study, male Wistar rats were infected with the Y strain of T. cruzi and then subjected to repetitive stress by exposure to ether vapor for 1min twice a day during the acute phase of infection. Stressed animals showed decreased lytic antibody activity and lowered levels of peritoneal macrophages. Despite an increase in the weight of the spleen, histological analyses demonstrated tissue alterations, the presence of amastigote nests, and a complete absence of activated lymphoid follicles. These results suggest that stress-induced increases in plasma corticosterone can suppress the immune response and worsen tissue injury during the acute phase of T. cruzi infection.

Dehydroepiandrosterone affects Trypanosoma cruzi tissue parasite burdens in rats.

Dehydroepiandrosterone (DHEA), the predominant steroid hormone produced by adrenal glands has significant effects on the immune system. DHEA enhances immune responses against a wide range of viral, bacterial, and parasitic pathogens. In the present study, we investigated the effects of DHEA treatment during the acute phase of experimental Trypanosoma cruzi infection. Male and female Wistar rats were infected with the Y strain of T. cruzi and treated subcutaneously with 40 mg/kg body weight/day of DHEA. Myocardial parasitism and inflammation were always present in the heart during the acute phase, in male and female infected animals, regardless of DHEA treatment, but the numbers of amastigote nests in cardiomyocytes were significantly lower in DHEA-treated rats. At the end of the acute phase, the nests became rare or virtually absent in all experimental infections. Histological analysis of the adrenal glands showed that treated males displayed an absence of parasites. DHEA treatment also resulted in reduced parasitisim of heart and adrenal glands, as indicated by fewer and smaller amastigote burdens, and less inflammatory infiltrate and tissue disorganization. DHEA treatment also resulted in thymic atrophy as measured both by reduced weight and by a reduction in the number of cultured activated thymocytes. In vitro analysis showed the number of activated macrophages was higher in treated animals. Antibody levels were monitored by complement-mediated lysis. Higher titers were observed in females when compared to males; but DHEA treatment enhanced the percentage of lysis for both sexes. These findings suggest that DHEA can play a role in the control of parasite multiplication.

Enzyme-linked immunoassay using recombinant trans-sialidase of Trypanosoma cruzi can be employed for monitoring of patients with Chagas' disease after drug treatment.

trans-Sialidase is an enzyme present on the surface of Trypanosoma cruzi and is an important antigen recognized by sera from patients with Chagas' disease. In the present study we investigated whether the benznidazole treatment of patients with Chagas' disease induced changes in the reactivity of serum toward a recombinant form of trans-sialidase in order to develop an assay for monitoring of patients after treatment for Chagas' disease, which is needed at Chagas' disease control centers. By using an enzyme-linked immunosorbent assay containing a recombinant protein corresponding to the catalytic domain of trans-sialidase, we found that the antigen had a high specificity for sera from untreated patients with Chagas' disease. Sera from healthy individuals or patients with active visceral leishmaniasis minimally cross-reacted with the antigen. Anti-trans-sialidase immunoglobulin was detected in 98% of 151 untreated patients with Chagas' disease. Of these, 124 patients were treated for 60 days with benznidazole (5 mg/kg of body weight/day), and their sera were assayed for reactivity with the recombinant trans-sialidase. By using this methodology, three groups of patients could be established. The first group (60 patients), which was considered to have been successfully treated, showed no reactivity after treatment. The second group (46 patients) still showed signs of infection, and after treatment their sera recognized trans-sialidase, but with reduced titers. The third group (18 patients) was considered to be resistant to drug treatment, and their sera presented identical reactivities before and after treatment. These results suggest that determination of the absence of antibodies to recombinant trans-sialidase in treated patients by the present assay is indicative of treatment success, while the presence of antibodies may indicate the persistence of infection. Therefore, this method may be useful for the diagnosis and monitoring of patients undergoing benznidazole treatment.

Enzyme-Linked Immunoassay Using Recombinant trans-Sialidase of Trypanosoma cruzi Can Be Employed for Monitoring of Patients with Chagas’ Disease after Drug Treatment

trans-Sialidase is an enzyme present on the surface of Trypanosoma cruzi and is an important antigen recognized by sera from patients with Chagas’ disease. In the present study we investigated whether the benznidazole treatment of patients with Chagas’ disease induced changes in the reactivity of serum toward a recombinant form of trans-sialidase in order to develop an assay for monitoring of patients after treatment for Chagas’ disease, which is needed at Chagas’ disease control centers. By using an enzyme-linked immunosorbent assay containing a recombinant protein corresponding to the catalytic domain of trans-sialidase, we found that the antigen had a high specificity for sera from untreated patients with Chagas’ disease. Sera from healthyindividuals or patients with active visceral eishmaniasis minimally cross-reacted with the antigen. Anti-transsialidase immunoglobulin was detected in 98% of 151 untreated patients with Chagas’ disease. Of these, 124 patients were treated for 60 days with benznidazole (5 mg/kg of body weight/day), and their sera were assayed for reactivity with the recombinant trans-sialidase. By using this methodology, three groups of patients could be established. The first group (60 patients), which was considered to have been successfully treated, showed no reactivity after treatment. The second group (46 patients) still showed signs of infection, and after treatment their sera recognized trans-sialidase, but with reduced titers. The third group (18 patients) was considered to be resistant to drug treatment, and their sera presented identical reactivities before and after treatment. These results suggest that determination of the absence of antibodies to recombinant trans-sialidase in treated patients by the present assay is indicative of treatment success, while the presence of antibodies may indicate the persistence of infection. Therefore, this method may be useful for the diagnosis and monitoring of patients undergoing benznidazole treatment...