Adsorption of ascorbic acid on the C60 fullerene.

Adsorption of ascorbic acid (AsA) on C60 is investigated using classical molecular mechanics and density functional theory (DFT). Classical annealing was performed to explore the space of molecular configurations of ascorbic acid adsorbed on C60, searching for optimal geometries. From the structure with the smallest total energy, 10 initial configurations were prepared by applying rotations of 90 degrees about three orthogonal axes. Each one of these configurations was optimized using DFT (for both LDA and GGA exchange-correlation functionals), and an estimate of their total and adsorption energies was found. Different configurations have minimal adsorption energies (defined here as the total energy of the adsorbate minus the total energy of the separate molecules) from -0.54 to -0.10 eV, with distinct optimal distances between the AsA and C60 centers of mass. According to a Hirshfeld population analysis, AsA is, in general, an acceptor of electrons from C60. Our results demonstrate the feasibility of noncovalent functionalization of C60 with AsA and provide minimal energy values for the several different configurations investigated. These results should be considered in reactions as a possible way to prevent against the oxidative damage and toxicity of C60. The beneficial effects of using AsA-C60 includes its action when administered together with levodopa, against the neurotoxicity generated by levodopa isolated, which opens new strategies for the Parkinson's disease treatment.

Synthesis and schistosomicidal activity of new substituted thioxo-imidazolidine compounds.

Synthesis and physico-chemical properties of 3-benzyl-5-(4-fluoro-benzylidene)-1-methyl-2-thioxo-imidazolidin-4-ones, 5-benzylidene-3-(4-nitro-benzyl)-2-thioxo-imidazolidin-4-ones and 4-acridin-9-ylmethylene-1-benzyl-5-thioxo-imidazolidin-2-ones compounds are described. These thioxo-imidazolidine derivatives were prepared by alkylation and condensation with 4-fluoro-benzaldehyde or nucleophilic Michael addition with cyanoacrylates. The schistosomicidal activity of 3-benzyl-5-(4-fluoro-benzylidene)-1-methyl-2-thioxo-imidazolidin-4-one compounds was evaluated.

Esquistossomose mansônica hepatoesplênica em adolescentes: carga parasitária residual após tratamento clínico-cirúrgico / Hepatosplenic mansonic schistosomiasis in adolescents: Residual parasitary burden after medical and surgical treatment

A esquistossomose na forma hepatoesplênica associada a varizes sangrentas do esôfago, hiperesplenismo e/ou hipoevolutismo, em adolescentes, tem sido tratada clinicamente com oxamniquime e cirurgicamente por esplenectomia, ligadura da veia gástrica esquerda e auto-implante esplênico. Nos casos de recidiva hemorrágica, os pacientes são incluidos no protocolo de escleroterapia endoscópica das varizes esofageanas. No seguimento pós-operatório desses pacientes tem sido observado a manutenção de hiperglobulinemia G e M, e, eosinnofilia, fazendo supor a possibilidade de manutenção de carga parasitária residual ou reinfecção. vinte e quatro pacientes, entre 11 e 20 anos, foram submetidos a biópsia retal e oograma quantitativo, além do Kato-Katz para verificação dessa possibilidade. Em 17 pacientes, o oograma foi negativo, entretanto, em sete, o exame foi positivo, dos quais, quatro apresentavam ovos viáveis. O Kato-Katz, com ovos viáveis foi igualmente, positivo nesses quatros pacientes. Observou-se associação positiva entre os elevados níveis séricos de imunoglobulina G e a positividade do oograma. Os achados indicam uma carga parasitária residual ou reinfecção em cerca de 17 por cento dos pacientes, o que poderia estar interferindo na evolução clínica desses pacientes

Detection of microfilarial antigen in circulating immune complex from sera of Wuchereria bancrofti-infected individuals.

Polyethylene glycol-precipitated circulating immune complexes (CICs) from the sera of patients with Bancroftian filariasis were examined for parasite antigen content by an ELISA. Of the 227 patients, 214 were asymptomatic microfilariae carriers with microfilaremias ranging between six and 14,000/ml blood, and 13 were symptomatic patients with chronic filariasis without microfilaremia. In addition, the sera of 10 of the patients treated with diethyl carbamazine were also examined. These assays were devised using mouse monoclonal antibody raised against microfilariae of Wuchereria bancrofti. Using an acid-phase covalent-bound plate for the ELISA makes it possible to assay the antigen contents simply. Microfilarial antigens were detected from 92 (43.0%) of microfilaria (mf)-positive individuals. Furthermore, the level of antigen in CIC was correlated with mf counts from night blood Nuclepore filtration results. Antigen was not detected in CIC from patients with a variety of nonfilarial helminth infections. These findings indicate that microfilariae play an important role of CIC formation in lymphatic filariasis.

Esquistossomose murina esperimental: estudo imunohistoquímicos das células ganglionares mioentéricas / Experimental murine Schistosomiasis: an immunohistochemical study of the ganglionic myoenteric cells

Para estudar a influência do processo granulomatoso esquistossomóticosobre as células ganglionares mioentéricas, foram utilizados 30 camundongos albinos Swiss infectadoscom 50 cercárias da cepa SLM do S. mansoni.O grupo controle foi constituído por dez animais näo infectados. Após sessenta dias de infecçäo, cortes histológicos do intestino delgadocorados por hematoxilina-eosina e P.A.S. demonstraram granulomas periovulares em todas as camadas da parede intestinal. Através do método imunohistoquímico indireto, usando-se a enolase neurônio-específica como marcador, observou-se desorganizaçäo do plexo mioentêrico em áreas contendo granulomas. Além disso, ocorreu rarefaçäo das estaçöes ganglionares, com aparente destruiçäo de células neuronais. A possível contribuiçäo dessas alteraçöes para a sintomatologia da esquistossomose humana é avaliada

Experimental murine schistosomiasis and thyroid function.

In humans the hepatosplenic form of schistosomiasis may be associated with some degree of somatosexual underdevelopment. In the present study we induced an experimental hepatosplenic form of schistosomiasis by infecting 21-day-old mice with the São Lourenço da Mata-PE strain of Schistosoma mansoni and evaluated thyroid function and its relationship with somatosexual development. Plasma levels of T3 and T4 were determined in 115-day old male albino Swiss mice by radioimmunoassay as a measure of thyroid function. Prepuberal infection with S. mansoni resulted in significant increases in liver (74%) and spleen (138%) weights, although there were no changes in animal growth or plasma T3 and T4 concentrations under the experimental conditions used. The present study demonstrates that prepuberal infection of mice with S. mansoni induces the development of a hepatosplenic form of schistosomiasis during adult life with apparently normal thyroid function.

Experimental murine schistosomiasis and thyroid function

In humans the hepatosplenic form of schistosomiasis may be associated with some degree of somatosexual underdevelopment. In the present study we induced an experimental hepatosplenic form of schistosomiasis by infecting 21-day-old mice with the São Lourenço da Mata-PE strain of Schistosoma mansoni and evaluated thyroid function and its relationship with somatosexual development. Plasma levels of T3 and T4 were determined in 115-day old male albino Swiss mice by radioimmunoassay as a measure of thyroid function. Prepuberal infection with S. mansoni resulted in significant increases in liver (74) and spleen (138) weights, although there were no changes in animal growth or plasma T3 and T4 concentrations under the experimental conditions used. The present study demonstrates that prepuberal infection of mice with S. mansoni induces the development of a hepatosplenic form of schistosomiasis during adult life with apparently normal thyroid function.

Studies on common antigenicities between the Belo Horizonte strain, Brazil of Schistosoma mansoni eggs and Biomphalaria snails by immunoelectrophoresis.

Immunoelectrophoretic studies of common antigenicities were carried out by using rabbit sera immunized against the Belo Horizonte strain of Schistosoma mansoni eggs and crude antigens of Biomphalaria snails and vice versa. With regard to common antigenicities between S. mansoni eggs and Biomphalaria snails, S. mansoni eggs produced 4 to 5 bands with Biomphalaria glabrata pigmentado, 3 to 4 bands with B. glabrata albino and only 1 band with B. straminea. In our laboratory, the infection rate of S. mansoni miracidia to B. glabrata pigmentado was 64.3% and 55.0% for B. glabrata albino, but B. straminea was not found to be susceptible to S. mansoni miracidia. It was observe that more bands were seen between S. mansoni egg and suitable hosts. Biomphalaria snail crude antigens were fractionated by Sephadex G-100 column, and each fraction antigen was tested with anti-S. mansoni egg sera by immunoelectrophoresis. As results, three fractions were collected form each snail strains. The common antigenicities between fractionated antigens from Biomphalaria snails crude antigens and anti-S. mansoni egg sera mostly existed in the first fraction and they were estimated to have molecular weights over 45,000.

Immunoelectrophoretic study on common antigens of São Lourenço da Mata and Belo Horizonte strains of Schistosoma mansoni adult worms and Biomphalaria snails.

Immunoelectrophoretic studies on common antigens were carried out by using rabbits sera immunized against São Lourenço da Mata and Belo Horizonte strains of Schistosoma mansoni adult worms and antigens of Biomphalaria glabrata pigmented (Jaboatão--PE); B. glabrata albino (Belo Horizonte--MG) and B. straminea (São Lourenço da Mata, PE). Furthermore, the reverse approach was proceeded, namely, sera anti Biomphalaria snails produced in rabbits were tested against both strains of Schistosoma adult worm antigens. The analysis of the common antigens between the SLM strains of S. mansoni adult worm and B. glabrata pigmented showed 8 to 9 precipitin bands, 3 bands with B. glabrata albino and only 1 band with B. straminea crude extracts. On the other hand, the BH strain of S. mansoni adult worm antisera produced 6 to 7 bands with B. glabrata pigmented, 5 bands with B. glabrata albino and 1 band with B. straminea antigenic extract. Biomphalaria snails crude extracts were fractionated by Sephadex G-100 column and three fractions were collected from each snail strain. The fractions were tested with anti SLM and BH strains of S. mansoni adult worm sera by immunoelectrophoresis. The common antigens fractionated from Biomphalaria snails crude extracts and those found for both strains of S. mansoni adult worm mostly existed in the first fraction and they were estimated to have molecular weight over 158,000 daltons. In our laboratory, it was found a relationship between the antigenic similarities and experimental infection rates of S. mansoni towards Biomphalaria snails so that more bands were seen with increasing infection rates of S. mansoni.