Biomedical subjects

C Cuéllar

Publications and source records attributed to C Cuéllar.

32 records · Page 2Linked to original sources

PubMed1999

Humoral immune responses induced by Gymnorhynchus gigas extracts in BALB/c mice.

The aim of this study was to determine if the plerocercoid larvae of Gymnorhynchus gigas, a common cestode of the ray's bream (Brama raii), possess antigenic compounds potentially capable of provoking anaphylactic episodes. A murine experimental model, using BALB/c mice, was developed to study the humoral immune response induced by G. gigas extracts. A highly specific humoral immune response was detected and cross-reactions were not observed between parasite and host antigens. The presence of IgM and IgG3 levels suggest the presence of thymus-independent antigens in the parasitic extract. The IgG antibody class showed the highest levels, with the IgG1 the predominant subclass. These IgG1 levels are in accordance with the supposed presence of a type I allergic reaction after the ingestion of G. gigas plerocercoids parasitizing fish, as well as inducing anaphylaxia in fish. These results indicate that somatic products released from ingested larvae of G. gigas could induce the development of a Th2 response capable of causing allergic disorders.

Anaphylaxis↗

PubMed1998

Effects of Anisakis simplex on nitric oxide production in J774 macrophages.

Since nitric oxide (NO) was recognized as a potent microbicidal agent, its role in host defence against intracellular parasites has been widely demonstrated. Recent evidence suggests a role for NO in combating extracellular and multicellular pathogens. This defence activity has been demonstrated toward the larvae of Schistosoma mansoni, microfilariae of Onchocerca linealis, several stages of Brugia malayi and protoscoleces of Echinococcus multilocularis. Many parasites suppress Th1 lymphocytes and directly inhibit NO production by inducing cytokines, such as IL-4, IL-10 and TGF-beta. In this study, we have investigated the effects of Anisakis simplex, an enhancer of Th2-dominant responses, on NO production. We studied the effect of crude extracts (CE) and excretory-secretory (ES) products on the induction of inducible nitric oxide synthase (iNOS) in bacterial lipopolysaccharide (LPS)-treated J774 macrophages. Stimulation of macrophages by LPS (1 microg/ml) increased nitrite concentrations in the culture medium at 24 h. Co-administration of A. simplex products with LPS, dose-dependently reduced the accumulation of nitrite. Nitrite production is due to induction of iNOS, and both L-NAME (N(G)-nitro-L-arginine methyl ester) (50 microM) and dexamethasone (10 microM) inhibited nitrite accumulation (54.2 and 92.1% inhibition, respectively). The inhibition of nitrite production by A. simplex was 42.1-97.8% in the range 4.75-76 microg/well (CE products) and 37.2-61.5% in the range 5-20 microg/well (ES products). Cell viability assayed by the mitochondrial-dependent reduction of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) verified that the inhibition was not due to general cellular toxicity. However, the effects of A. simplex, were reduced when NOS had been induced by prior exposure to LPS and any possible further induction was blocked by cycloheximide, an inhibitor of protein synthesis.

Animals↗

PubMed1998

Isotype-specific immune responses in murine experimental anisakiasis.

A murine experimental model of anisakiasis has been developed in BALB/c and C57BL/10 mice orally inoculated with an Anisakis simplex living third stage larva (L3) in order to investigate isotype-specific immune responses against excretory-secretory (ES) products and crude extracts (CE) from L3. Specific antibody production showed similar patterns against both ES and CE antigens with higher levels against the latter. The dynamics of the production showed the earliest responses in BALB/c, in which antibodies were principally of the immunoglobulin (Ig)M isotype. Responses to the IgG1 subclass were mainly produced in the C57BL/10 strain. Levels of IgG2a were practically undetectable. With sera from C57BL/10 mice high levels of the IgG2b isotype were detected. A slight IgG3 response was only detected against the CE antigen in the C57BL/10 strain by the end of the experiment and IgA responses were very low. Humoral responses against A. simplex antigens are different depending on individual characteristics and thymus-independent epitopes might be represented into A. simplex antigens and their stimuli could be different regarding the murine strain used.

Animals↗

PubMed1997

Serological evidence of toxocariasis in patients from Spain with a clinical suspicion of visceral larva migrans.

Sera from patients with clinical characteristics of toxocariasis were assayed using the ELISA method and larval excretory-secretory antigen. Four hundred and seven samples of Toxocara serology were received at the laboratory of Ciudad Sanitaria Juan Canalejo Hospital of Corunna, Spain, from 1984 to 1989. Of these, 30 were from adults, 332 from children and 45 from patients of unknown age, resulting in Toxocara seroprevalences of 23.3%, 32.8% and 17.7% respectively. The reasons for these serological differences in the rural and urban areas of Galicia, Spain are discussed.

Adolescent↗

PubMed1997

Genomic identification of Anisakis simplex isolates.

RAPD technique was used to differentiate individuals of Anisakis simplex obtained from Merluccius merluccius, Phycis blennoides, Conger conger and Lepidorhombus boscii, from the North Atlantic Ocean. The amplification patterns of the host DNA controls were markedly different from those obtained for the parasitic material. No variation within the same host was detected. The amplification patterns for larvae obtained from fish of the same genus were somewhat different. The amplification patterns of A. simplex isolates from M. merluccius, P. blennoides, C. conger and L. boscii, were different. These results suggest the possible existence of two populations with a considerable high genetic variability and a different adaptation to different host species.

Animals↗

PubMed1997

Recidivous acute urticaria caused by Anisakis simplex.

This study aimed to determine the cause of acute recidivous urticaria in patients who usually eat fish or other seafood. Twenty-five patients were studied. The skin prick test with larval Anisakis simplex extract was performed; total and specific IgE against A. simplex was measured with the CAP System; specific antibodies to A. simplex were determined by ELISA; and immunorecognition patterns of the sera were studied by Western blot. Nineteen patients showed specific IgE to A. simplex, but specific IgE to Ascaris was demonstrated in only two patients. No patients reacted to Toxocara canis or Echinoccocus granulosus antigens with the same test. The skin prick test was positive in 16 patients, in two of them persisting for 48 h. Five patients showed neither skin reaction nor specific IgE to A. simplex. Sera showed specific immunoglobulin levels against A. simplex larval crude extract, by both ELISA and Western blot. Likewise, specific immunoglobulin levels against excretory-secretory antigen were also measured by ELISA. Only one patient showed sensitization to fish. A. simplex was found to be the main cause of acute recidivous urticaria in patients who usually eat fish and are not sensitized to it.

Adolescent↗

PubMed1996

In vitro study on the effect of larval excretory/secretory products and crude extracts from Anisakis simplex on blood coagulation.

The anticoagulant action of Anisakis simplex larvae on human blood in vitro was examined. Anticoagulant activity was assessed by routine screening tests that evaluate the overall competency of the coagulant mechanism. A slight prolongation of the prothrombin time (PT) was observed with the larval crude extracts. Prolongation of the PT was seen at a concentration of excretory/secretory (ES) products greater than 62.5 micrograms/ml. No prolongation of the activated partial thromboplastin time (PTT) was observed using crude extracts. There was a prolongation of the PTT with ES products at concentrations greater than 62.5 micrograms/ml. ES products of the larvae were able to prolong coagulation times indicating that they contain an inhibitory or anticoagulant property. Preparation of crude extracts of A. simplex showed only minimal anticoagulant activity. The results obtained by measurements of the PT and the PTT suggest a probable alteration of one of the coagulation proteins namely factors Xa, IIa or Va. These findings suggest that the anticoagulant activity demonstrated in the ES products may play an important role during invasion of the gastric or intestinal mucosa by larvae and could have biological significance in infected patients.

Animals↗

PubMed1996

Enzyme-linked immunosorbent assay, immunoblot analysis and RAST fluoroimmunoassay analysis of serum responses against crude larval antigens of Anisakis simplex in a Spanish random population.

The results obtained in a study of seroprevalence by means of ELISA and immunoblot with crude larval extracts of Anisakis simplex using 1008 human sera from Spanish people showing no clinical suspicion of anisakidosis are given. For the evaluation of the results obtained by ELISA the Diagnostic Index (DI) was used, as the ratio between the optical density resulting from the test serum and the optical density of the negative control. Forty-seven sera showed DIs between 1.5 and 2, and 14 sera were greater than 2. After comparison of the immunoblot analysis with the immunorecognition pattern of a human anisakidosis reference serum, a diagnostic criterion could be established for those sera that, at a 1/100 dilution, showed a DI by ELISA greater than 1.5. Seven of 14 selected sera with DIs in ELISA higher than 1.3 showed anti-Anisakis specific IgE antibodies by RAST fluoroimmunoassay.

Adult↗

PubMed1995

Evaluation by larval recovery of mebendazole activity in experimental murine toxocariasis.

We have studied the action of mebendazole on experimental murine toxocariasis using different formulations and vehicles. The treatment efficacy was evaluated by larval recovery after digesting several tissues. In the first part of the experiment, the drugs were administered on days 1-3 post infection (p.i.) inclusive (hepato-pulmonary phase of the migration), then the animals were sacrificed by the 1st week p.i. In the second part of the experimental protocol, the treatments were administered on days 4-6 p.i. inclusive (myotropic-neurotropic phase of the migration), with sacrifice of the animals by the 7th week p.i. The 2nd pattern of treatment reduced more effectively the total larval recoveries compared with control animals. However, the larval distribution by organs was scarcely affected. The first pattern of treatment reduced less effectively the total number of larvae, but it significantly inhibited migration.

Animals↗

PubMed1995

Cross-reactions of sera from Toxascaris leonina and Ascaris suum infected mice with Toxocara canis, Toxascaris leonina and Ascaris suum antigens.

The ELISA method using larval ES products and homogenized Toxocara canis, Toxascaris leonina and Ascaris suum adult worms extract, was used to determine the possible cross-reactions in BALB/c and C57BL/10 mice inoculated with embryonated eggs or adult worms extract of T. leonina of T. leonina or A. suum in single and multiple doses. When we used sera of mice infected with embryonated eggs of T. leonina against different heterologous Ag, no cross-reactions against T. canis ES and A. suum ES Ag were observed using a single dose. Similarly, in multiple doses no response against T. canis ES Ag was observed. In mice inoculated with adult worms extract of T. leonina cross-reactions with T. canis ES and A. suum ES Ag did not occur. Sera from BALB/c mice infected with embryonated eggs of A. suum, was tested using ES Ag from both A. suum and T. canis and no reactions were observed. This fact confirmed the resistance of this murine strain to A. suum embryonated eggs. When we used sera of susceptible C57BL/10 mice infected against different heterologous Ag, we observed no cross-reactions against T. canis ES Ag. In the case of both BALB/c and C57BL/10 and C57BL/10 mice immunized with a single dose of A. suum adult crude extract no cross-reactions were seen against ES T. canis Ag and with sera from C57BL/10 mice against ES T. leonina. These facts confirmed the specificity of the ES T. canis Ag.

Animals↗

PubMed1994

Larval distribution of Toxocara canis in BALB/c mice at nine weeks and one year post-inoculation.

The migratory route of Toxocara canis in the mouse includes two phases: a hepato-pulmonary phase and a myotropic-neurotropic phase. A study was made of the migratory behaviour of larvae one year post-inoculation (p.i.) comparing the results to those obtained at the end of an initial experiment (day 63 p.i). The larval distribution per organ was already definitive at 9 weeks p.i. The total parasitic load showed a reduction when the experiment was prolonged for one year.

Animals↗

PubMed1992

Persistence of immune response in human toxocariasis as measured by ELISA.

The antibody titer was followed in a group of patients, clinically diagnosed with toxocariasis, during a 5 year period. We observed that larvae can survive for at least 5 years in humans. Antigenic stimulation was enough to keep high levels of immunoglobulins over this period. Antibody levels decreased slowly and this pattern is similar to that shown by animal models.

Animals↗

PubMed1992

Cross-reactions of sera from Toxocara canis-infected mice with Toxascaris leonina and Ascaris suum antigens.

The ELISA method using larval excretory-secretory (E/S) products and homogenized Toxocara canis, Toxascaris leonina and Ascaris suum adult worm extract were used to determine possible cross-reactions in BALB/c and C57BL/10 mice, inoculated with embryonated eggs or adult worm extract of T. canis in single and multiple doses. When we used sera of mice infected with embryonated eggs of T. canis against different heterologous antigens, we observed no cross-reactions in BALB/c mice against A. suum E/S and adult worm extract antigens with a single dose. In multiple doses this was absent too against T. leonina adult worm extract in BALB/c mice, and in both strains against A. suum E/S and adult worm extract. In BALB/c mice inoculated with adult worm extract of T. canis we did not observe cross-reactions with A. suum E/S antigen with both inoculation doses. In the remainder of the experiments, we observed cross-reactions of different intensities.

Animals↗

PubMed1987

Comparative study of assays detecting circulating immune complexes and specific antibodies in patients infected with Toxocara canis.

A sandwich ELISA method using previously described E/S antigen-specific monoclonal antibodies has been developed to detect circulating immune complexes in patients infected with Toxocara canis. This technique could be used for the study of the dynamics of the parasite-host relationship, as we believe the detection of immune complexes and/or soluble antigen to be an improvement over detection of antibodies only. In this parasitosis, antibodies may be present in residual levels for prolonged periods after active infection.

Animals↗