Frequency of Toxocara canis antibodies in Mexican paediatric patients with epilepsy.

The relationship between epilepsy and the presence of visceral larva migrans caused by Toxocara canis in Mexican children remains uncertain; however, this relationship needs to be elucidated because these parasite larvae can invade the human central nervous system. Accordingly, this study aimed to determine the frequency and specificity of anti-T. canis antibodies in the sera of children with epilepsy to determine the relationship between this parasite and epilepsy. The sera samples of 214 children were examined: 111 children diagnosed with epilepsy and 103 clinically healthy children without neurological disorders. In the sera of each group, the presence and specificity of anti-T. canis and anti-Ascaris lumbricoides antibodies, as well as the cross-reactivity between them, were assessed using enzyme-linked immunosorbent assay and Western blotting analysis. Among the children with epilepsy, 25.2% exhibited seropositivity to T. canis. Cross-reactivity against the A. lumbricoides antigen was present in 46.8% of the children with epilepsy, whereas 11.7% of the children with epilepsy and anti-T. canis antibodies did not exhibit cross-reactivity against this antigen. The Western blotting analysis of the sera from the children with epilepsy demonstrated the presence of T. canis proteins, with molecular weights of 24, 35, 55, 70, 120 and 210 kDa, and A lumbricoides proteins with molecular weights of 70, 80 and 110 kDa. Our results revealed the presence of anti-T. canis antibodies in the children with epilepsy; furthermore, cross-reactivity tests with A. lumbricoides showed the importance of the presence of anti-T. canis antibodies in revealing the relationship between this parasite and epilepsy in children.

In vitro activity of two phenyl-carbamate derivatives, singly and in combination with albendazole against albendazole-resistant Giardia intestinalis.

Giardia intestinalis is one of the most prevalent parasites in adults and children in Mexico. Benzimidazoles have been proposed as a therapeutic alternative in the treatment of giardiasis. However, high-dose related toxicity and the development of resistance have emerged in clinical trials using this therapy. In the search of alternative drugs, we found that benzimidazole-resistant strains of fungi have shown increased sensitivity to phenyl-carbamates, hence, we developed several substituted phenyl-carbamates, two of which were tested against the protozoan parasite G. intestinalis in susceptible and albendazole-resistant Giardia strains. 4-R-ethyl-phenyl-carbamates IRE-6A and IRE-7B demonstrated antigiardial, albeit modest, activity when compared with albendazole, against susceptible and albendazole-induced resistant Giardia. However, when albendazole 0.38 microg/mL (MIC(50)) was combined with each IRE compound, a significant antigiardial synergism (fractional inhibitory concentration index (FICI < 0.5)) was obtained not only with sensitive cultures but also with resistant Giardia parasites. The results described here suggest a potential role for a combined therapy with phenyl-carbamates and sub-doses of benzimidazoles in the treatment of giardiasis.

Relationship between free radicals produced by entamoeba histolytica and its proteases complex activity.

Entamoeba histolytica is a parasite which causes health problems and there has been many approaches to know what is the factor causing its pathogenicity. In the present work, we assayed if the production of free radicals by the amoeba, has a relationship with the proteases activity. When we test the DMSO action (free radicals quenching activity) the specific activity of the proteases complex of the parasite were affected also. At 33.3% (V/V) concentration of DMSO it was present a maximal decrease of the initial activity (about 46% decrease), for to a higher concentrations existing a trend to recuperate the original activity, suggesting that the free radicals are an important factor for the hydrolysis grade of the protein substrate. All the differences except those between 46.7 and 66.6%, were significantly different compared with the control without any addition. The effects of Probucol and Probucol plus DMSO, compared to those caused by Metronidazol (MZ). We can observe that the quenchers caused a decrease on proteases activity similar to that of MZ (which is an antiparasite drug) and it was of c.a. 58% of activity decrease. These data suggest that the action of both, free radicals and proteases complex of Entamoeba histolytica, can account for the pathogenicity of the parasite.

[Pathogenic activity modulation of Escherichia coli TL+ toxin with an isolated protein of Giardia intestinalis and a synthetic peptide]. / Modulación de la actividad patogénica de la toxina TL+ de Escherichia coli con una proteína aislada de Giardia intestinalis y un péptido sintético.

UNLABELLED: It is know that a protein from Giardia intestinalis works as a substrate for V. cholerae and Escherichia coli. The toxic activity of both activates protein G form intestinal mucosa with a pathogenic activity results. In the present study, the pathogenic activity of subunit A of Vibrio cholerae toxin (ADP-ribosyltranferase) using isolated fragments from: Giardia intestinalis and a synthetic peptide were used as modulators in vivo. MATERIAL AND METHODS: Adult Neo Zealand males rabbits with ileal loop were prepared and different mixtures of heat labile enterotoxin obtained from Escherichia coli H10407 and ARF protein isolated by electrofocusing from Giardia intestinalis Portland I were inoculated in the loops. The toxin activity was evaluated by luminal liquid secretion and cyclic AMP concentration in tissues (each loop). RESULTS: ADP ribosyltranferase activity was modulated, due to a decreased of luminal secretion and cAMP in tissues. Such results were seen when synthetic peptide and subunit A from Vibrio cholerae were used. CONCLUSIONS: The ADP ribosyltranferase activity of heat labile Escherichia coli and Vibrio cholerae toxins were modified by in vitro and in vivo interaction with ARF protein, which modified pathogenic effect over rabbits intestinal epithelium.

Early detection of Trichinella spiralis infection by the polymerase chain reaction in blood samples of experimentally infected mice.

Up to now, there is no useful method to diagnose trichinellosis at the early stages of infection. The aim of the present investigation was to know if the polymerase chain reaction (PCR), could detect DNA of migratory larvae in mice experimentally infected with T. spiralis. Thirty-three Balb/c female mice 4.6 weeks old, were infected with 300 larvae of T. spiralis/mouse. Blood samples of these animals were positive for T. spiralis at 3rd and 17th post-infection days. The control group was negative. PCR could detect from one to 200 larvae. Our results showed that it was possible to make early diagnosis of trichinellosis in blood of mice infected with T. spiralis.

Clasificación genética de 'Giardia intestinalis' en niños sintomáticos y asintomáticos / Genetic characterization of "giadia intestialis" in symptomatic and asytomatic children

Objetivo: Clasificar genéticamente aislados humanos de Giardia intestinalis provenientes de niños sintomáticos y asintomáticos con y sin enfermedad, para investigar utilizando el gen ribosomal 16S polish si existen diferencias entre ellos que permitan inferir relaciones con su comportamiento frente al huésped. Pacientes y métodos: Se determinaron las diferencias del gen ribosomal 16S polish de 17 aislados de G. intestinalis obtenidos de las heces de 11 niños con enfermedad digestiva, como diarrea crónica o recurrente, dolor abdominal, vómito, ausencia de fiebre, y 6 niños sin ella considerados asintomáticos: En ambos grupos las edades oscilaron entre 6 y 12 años. Se incluyó la cepa Pórtland, así como cuatro aislados de Giardia, obtenida de perros como control de comparación. Se aisló el ADN de las diferentes muestras y se amplificó el gen ribosomal 16S polish por la reacción en cadena de la polimerasa (PCR). El producto amplificado se sometió a secuenciacion y se analizó con el programa informático Clustal-W (1.81).Resultados: El porcentaje de alineación de las secuencias obtenidas de los aislados de niños sintomáticos mostró tres grupos de similitud con la cepa Pórtland. El primero del 80 al 90 por ciento, otro del 60 al 50 por ciento, y el último del 20 al 30 por ciento; sólo un aislado fue del 5 por ciento. En cuanto a los niños asintomáticos, sólo un aislado presentó semejanza con la cepa Pórtland; las demás fueron muy diferentes, observándose semejanzas entre ellas de un 80-90 por ciento. Con los aislados de perros los alineamientos presentaron semejanzas entre ellos del 70 al 80 por ciento. Conclusiones: Podríamos inferir que las diferencias en las secuencias de Giardia al amplificar el gen ribosomal 16S en los tres grupos estudiados ponen de manifiesto la plasticidad en el genoma de Giardia y que esto está relacionado con las características del huésped, ya sea sintomático, asintomático o animales (AU)

[Genetic differentiation with restriction patterns between pathogenic and non-pathogenic monoxenic Entamoeba histolytica]. / Diferenciación genética por patrones de restricción entre Entamoeba histolytica monoxénica patógena y no patógena.

UNLABELLED: Cysteine-proteinase of Entamoeba histolytica have been considered implicated like important virulence factors in the pathogenesis of amebiasis. On the basis of the differences in ethnic gene that encodes to 30 kDa proteinase. The present study validated a strategy to differentiate strains of pathogenic and non-pathogenic Entamoeba histolytica by restriction patterns. MATERIALS AND METHODS: Thirteen stool samples with Entamoeba histolytica cyst from 4 asymptomatic and 9 symptomatic patients ages and sex different into Robinson' medium were used. DNA obtained was used by amplified gene ethnic and it was cut with restriction enzyme Taq I and Hinf I. RESULTS: All strains were cultivated into Robinson's medium. A 530 bp fragment which hybridated with probe for Entamoeba histolytica was obtained. By the way valuation by restriction patterns with Taq I and Hinf I show that two of four samples of asymptomatic patients belong to pathogenic strain. It agrees with control strain positive HM-1:IMSS. Last 9 belonged to symptomatic patients with pathogenic strain. CONCLUSIONS: These results indicate that ethnic amplified by polymerase chain reaction is insufficiently to establish differential diagnostic. Therefore is necessary carry out enzyme digestion to identify pathogenic strain.

[Separation of the ventral disc proteins of Giardia intestinalis]. / Separación de proteínas del disco ventral de Giardia intestinalis.

We used repeat isoelectric focusing to obtain cytoskeleton proteins of Giardia intestinalis with the characteristics of giardins and tubulins of the ventral disk. Their molecular weight and its variants by pH difference ranged between 30 and 45 kDa. Polypeptides with molecular weights between 97 and 115 kDa were also obtained. Our immunocytochemical studies showed that the proteins with high molecular weight were from the membrane of the trophozoites; in a smaller proportion we observed also proteins with molecular weights similar to those of giardins and tubulins.

[In vitro decrease of the cytolytic effect of E. histolytica by inhibition of its phosphofructokinase]. / Disminución in vitro del efecto citolítico de E. histolytica por inhibición de su fosfofructocinasa.

The C14 radioactive label of PPi analogues was incorporated to E. histolytica after 24 hours of incubation at 37 degrees C; more than 90% of trophozoites remained viable. The PPi dependent phosphofructokinase was isolated in order to determine its kinetic parameters. With PPi, the Km was 18.06 +/- 0.91 micromol/mL-1. Using three different PPi analogues (tetrasodium salts) of (I) 1,1 hydroxy-methyl diphosphonate; (II) 1,1 hydroxy ethylene diphosphonate; (III) 1,1 hydroxy-nonano diphosphonate, KiI was 35.19 +/- 1.74; KiII was 42.65 +/- 0.65, and KiIII 2as 62.81 +/- 0.27 micromol/mL-1. The graphic expression of these results shows that the enzyme was competitively inhibited by the three analogues. When trophozoites were incubated with each one of the three inhibitors, a correlation was observed between the concentration and the cytolytic inhibition with an r = 0.98. Nevertheless, the slope obtained was different for each one of them. The smallest concentration of inhibitor to achieve a 50% lysis inhibition of trophozoites was that of inhibitor III. In addition, it was demonstrated that the incubation of the trophozoites with this inhibitor increased the time needed to destroy CHO cells. We conclude that enzymatic inhibition of the PPi dependent phosphofructokinase caused by the PPi analogues was responsible for the modification of the lytic capacity of trophozoites, possibly by altering the metabolic pathway of carbohydrates.

Purificacion parcial de algunos antigenos de superficie de E. histolytica. Investigacion de la actividad biologica frente a sueros de pacientes con absceso hepatico amibiano. / Partial purification of some surface antigens of E. histolytica. Research on biological activity in serum of patients with amebic liver abscess

Se aislaron y purificaron parcialmente antigenos proteicos de la superficie de trofozoitos de E. histolytica, cepa HM1, mediante las tecnicas de radioyodacion y radiosulfonacion.Se demostro por inmunodifusion la ausencia de albumina en la superficie de los trofozoitos.En el proceso de aislamiento, se adicionaron inhibidores enzimaticos para evitar la accion enzimaticade las hidrolasas durante la homogenizacion, se demostro por inmunofluorescencia que los antigenos aislados fueron de superficie. Se investigo si los antigenos presentaron actividad inmunologica frente a sueros de pacientes con absceso hepatico amibiano por inmunodifusion. Se correlaciono el titulo de anticuerpos por hemaglutinacion pasiva directa utilizando como antigeno las proteinas obtenidas de superficie y el titulo obtenido con los antigenos de la amiba completa. Se encontro un valor de r=0,72