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Biomedical subjects

A Flisser

Publications and source records attributed to A Flisser.

At least 91 records · Page 5Linked to original sources
PubMed1986

Characterization by enzyme-linked immunosorbent assay of the humoral immune response in patients with neurocysticercosis and its application in immunodiagnosis.

The enzyme-linked immunosorbent assay was standardized for the search for specific antibodies in human neurocysticercosis. A crude cysticercal extract and two partially purified antigenic fractions were used, as well as serum and cerebrospinal fluid (CSF) samples of different groups of subjects. Immunoglobulin G (IgG) antibodies were detected in serum and CSF, with a sensitivity of 85 and 90%, respectively. Specificity was 96% with a partially purified antigen and 100% with the crude cysticercal extract. IgM and IgA antibodies were detected less frequently, and IgE was detected only occasionally, both in serum and CSF. Analysis of serum and CSF samples drawn from the same patient did not always reveal the presence of anticysticercus antibodies in both samples. A significant correlation was found between the presence or absence of IgG antibodies in the CSF and the morphological appearance of the parasite (undamaged or calcified). Variations in the humoral response were not found to correlate with clinical and laboratory findings.

Adolescent↗
PubMed1985

Heterogeneity of humoral immune components in human cysticercosis.

Twelve Taenia solium cysticerci, obtained from several human organs, were examined by immunofluorescence for IgG, IgM, IgA, IgE and C3b on their surfaces. Anti-cysticercus antibodies of the 4 classes of immunoglobulins were looked for in the cerebrospinal fluid of most neurologic patients, in the intraocular humors of a patient with eye cysticercosis, and in the serum of some other patients. The morphological appearance of the parasites as well as the clinical features of the patients were recorded. The distribution of components was heterogeneous among the different parasite surfaces. IgG was the most frequent, followed by IgA, IgM, C3b and IgE. No correlation was found between the presence of these molecules and signs of damage in the cysticerci, or with the classes of immunoglobulins found as anti-cysticercus antibodies. Possible explanations of these findings as well as the implications of heterogeneity in cysticercosis are discussed.

Adolescent↗
PubMed1983

Fibronectin-like properties in antigen B from the cysticercus of Taenia solium.

The most prominent antigen of the cysticercus of Taenia solium in the serology of human cysticercosis, antigen B, is capable of agglutinating red blood cells of different species, of aligning in vitro cell growth of transformed mouse fibroblasts, and of strongly binding to pig, rat and human collagen. Scatchard analysis of the adsorption isotherms indicates quite avid heterogeneous binding of antigen B to rat collagen (K's = 10(3), 10(5)). These remarkable biological activities of antigen B, resembling those of fibronectins, allow for some speculation concerning its role in the host-parasite relationship (i.e. organizing vicinal host components to improve the parasite's lodging niche; the 'smoke screen' effect for the host's immune response; Clq inhibition), and expand fibronectin-like properties to molecules from Phyla other than vertebrates.

Animals↗
PubMed1982

Analysis of antigenic variation in cysticerci of Taenia solium.

By studying the reactions and cross-reactions of antigen extracts from different collections of Taenia solium with their respective hyperimmune antisera, and by using numerical taxonomy to analyze the results, a measure of antigenic diversification within T. solium was established. Results varied somewhat depending on the immunological method employed. Double immunodiffusion and immunoelectrophoresis agreed in that all cysticerci were not identical, but shared approximately one third of their antigens. Double immunodiffusion recognized two groups of identical cysticerci: one included 50% of the cysticerci and the other, 21%. Immunoelectrophoresis was more discriminatory in that it recognized few extracts as identical. Electrophoretic data revealed that the most frequently shared antigen among cysticerci corresponded to that most frequently detected by immunologically responsive humans with cerebral cysticercosis. Antigen diversification of T. solium may provide a possible explanation of the pleomorphic immune response of man to this parasite.U

Animals↗
PubMed1980

Human cysticercosis: antigens, antibodies and non-responders.

Immunoelectrophoresis of sera from patients with brain cysticercosis against a crude antigenic extract from Cysticercus cellulosae indicates that nearly 50% of the patients do not make sufficient antibodies to ostensively precipitate. The other 50% of the patients who do make precipitating antibodies show a very heterogeneous response in the number of antigens they recognize as well as in the type of antigen--as classified by their electrophoretic mobilities. The most favoured, called antigen B, is recognized by 84% of positive sera and corresponds to one or a limited number of antigens isoelectric at pH 8.6. Indirect immunofluorescence with monospecific anti-human immunoglobulins, performed upon the immunoelectrophoretic preparations, reveal that all cysticercus antigens induced the synthesis of antibodies in the immunoglobulin classes in the order G greater than M greater than E greater than A greater than D. Finally, antigen H (an anodic component) seems to favour IgE relative to its ability to induce IgG. Thus, although in natural infection a good proportion of cysticercotic patients do not seem to mount an energetic antibody response against the parasite, giving rise to some speculations about immunosuppression, the fact that 50% do synthesize antibodies allows for some optimistic expectations from vaccination of humans--in view of the good results of vaccination in experimental animals mediated by IgG antibodies. A likely prospect for a human vaccine would be antigen B because it is the most frequently detected by humans, although its immunizing and toxic properties remain to be properly studied.

Antibody Formation↗
PubMed1979

Immunogenic complexes obtained from Salmonella typhi-murium and Salmonella typhi Ty2 by the bacterial acetone powder method.

An immunogenic complex was isolated from Salmonella typhi-murium and another one from Salmonella typhi Ty2. Both were prepared by the bacterial acetone powder method which eliminated the cell wall, the DNA almost completely and the membrane phospholipids. The complexes were denominated "New Vaccines". The S. typhi-murium new vaccine induced, even at doses of 0.5 microgram dry weight per mouse, a high degree of protection against the challenge of the virulent microorganism. By immunoelectrophoresis, 21 antigen-antibody systems could be detected, two of them corresponding to O antigens. The S. typhi Ty2 new vaccine induced better protection than the standard vaccine (heat-phenol inactivated typhoid vaccine) when both vaccines were compared in the relative potency test. Moreover, the new vaccine had very low toxicity when inoculated in humans at doses of 1 microgram dry weight, able to elicite a high antibody titre (1/1,790 mean of 10 sera) in 75% of the tested population, estimated by the complement fixation test. In contrast, the standard vaccine induced a low antibody titre (1/222, mean of 5 sera) in 50% of the humans inoculated with 1 X 10(8) bacterial cells. The new vaccine did not induce undesirable effects whereas the standard vaccine induced an important inflammatory process in 100% of the cases, with intense local pain in 67% after 24 h post-first inoculation as well as other less severe symptoms.

Acetone↗
PubMed1979

The immunology of human and animal cysticercosis: a review.

In this review of the literature concerning the immunology of animal and human cysticercosis, emphasis is placed on whether previous exposure to the antigen confers protection to the host. Statistical analysis of the published data indicates that immunized animals have a lower risk than non-immunized animals of contracting cysticercosis, there being large variations within and between different host-cysticercus relationships. There is no indication as to which antigen is best for immunization but, although live parasites in all stages of development, or extracts, appear to give protection, embryos, eggs, and excretions are most frequently used. Antibodies appear to be the principal mediators of resistance, but the action seems to be only upon very young larvae, while fully grown cysticerci are unharmed. Several immunological methods are valuable in the diagnosis of cysticercosis, the choice depending more on the purpose of the study than on differences in their ability to discriminate between healthy and sick. The presence of anticysticercus antibodies in the serum of up to 50% of human patients indicates that human vaccination may be possible in high-risk areas; the remaining patients pose an interesting problem open to speculation and research on immunological evasion, immunodepression, and the existence of serotypes.

Animals↗
PubMed1976

[Seroepidemiologic study of human cysticerosis in the predominantly indigenous rural Indian population of the State of Chiapas].

The overall proportion of sera with antibodies against cyticercus antigens in 3226 serum samples collected among the Indian rural population in the proximity of San Cristóbal de Las Casas, Chiapas, México is 0.49. The proportion of positive sera varied from 0.4 to 7.6% inversely with the number of inhabitants in the community. The global proportion of positive sera in Chiapas being considerably lower than that expected from the autopsy frequency of brain cysticercosis in México City (1.4-3.6%), it is perhaps indicative of different epidemiologic dynamics in rural and urban areas.

Antibodies↗
PubMed1975

[Immunoelectrophoresis and double immunodiffusion in the diagnosis of human cerebral cysticercosis].

This paper describes the immune reactivity of the sera of humans with different probabilities of suffering cerebral cysticercosis as measured in immunoelectrophoresis and double diffusion against antigenic fractions from the wall, the liquid and the scolex of Cysticercus cellulosae. The proportion of positive sera with any antigenic fraction increased with the likelyhood of suffering cerebral cysticercosis, although some variation was found between antigenic fractions. Scolex and wall antigens showed the maximal discriminatory power between sick and healthy individuals: the probability of a false positive being less than 0.05 and that of a false negative ranging between 0.4 and 0.5. With these estimates it is concluded that a positive serum in immunoelectrophoresis or double diffusion against scolex or wall antigens practically establishes the diagnosis of cerebral cysticerocosis, although this event will occur in only half of the patients afflicted by the disease. The ease of execution of these tests and their discriminatory power between healthy and sick humans justify their establishment among diagnostic tools in cerebral cysticercosis.

Antigen-Antibody Reactions↗
PubMedDate not supplied

Human neurocysticercosis: comparison of enzyme immunoassay capture techniques based on monoclonal and polyclonal antibodies for the detection of parasite products in cerebrospinal fluid.

Current diagnosis of neurocysticercosis relies mostly on computerized tomography and nuclear magnetic resonance, with detection of antibodies being confirmatory rather than decisive. An assay which detects parasite products in cerebrospinal fluid would conclusively demonstrate a current infection and could be important when decisions regarding treatment must be made. Cerebrospinal fluid from patients with neurocysticercosis was used in 4 enzyme immunoassay capture tests designed to detect parasite products. Of the systems tested, one, based on the use of a monoclonal antibody reactive with a surface and secretion component of the metacestode, was particularly promising, giving a sensitivity of 72%. The assay has the double advantage of a very low background and a proved specificity for the products of living cysticerci. The other 3 systems (monoclonal anti-vesicular fluid antibody, polyclonal antibody against a saline extract and polyclonal anti-antigen B antibody) were less sensitive. Results with the anti-antigen B system support the proposal that products of low immunogenicity are the most appropriate targets for the serological detection of the parasite.

Adult↗
PubMedDate not supplied

Comparison of two assays (EIA and EITB) and two samples (saliva and serum) for the diagnosis of neurocysticercosis.

The enzyme immunoassay (EIA), standardized with a crude extract, and the enzyme-linked immunoelectrotransfer blot assay (ETIB) with glycoprotein antigens, were compared by using saliva and serum in the search for specific antibodies against Taenia solium larvae, for the diagnosis of neurocysticercosis. Saliva was slightly more sensitive in EIA (82.1%) than serum (74.1%). In EITB serum was far more sensitive (100%) than saliva (70.4%). The use of EITB with serum is thus an excellent choice for diagnosis of clinical cases of neurocysticercosis, while EIA using saliva represents a useful combination for diagnosis and, especially, epidemiology, because saliva is easily obtained by a painless and non-invasive procedure and the technique is simpler to perform. Furthermore, cross-reactivity of EIA with Echinococcus does not interfere in countries like Mexico where human hydatid disease is not present.

Animals↗
PubMedDate not supplied

Epidemiological investigation of Taenia solium taeniasis and cysticercosis in a rural village of Michoacan state, Mexico.

We performed a survey for taeniasis and cysticercosis among persons living in a Mexican village where Taenia solium infection in pigs was known to be enzootic. A standardized questionnaire was administered in all 577 households to obtain medical histories and information on demographic and environmental factors and on risk factors associated with transmission of infection. Serum and/or stool specimens were obtained from 1005 volunteers and examined for cysticercosis antibodies and intestinal parasites. Faecal examination of 828 participants revealed infection by Taenia sp. in 2 (0.2%). Three additional cases of taeniasis were detected in individuals who evacuated proglottids after treatment with praziquantel. Of 1005 human serum specimens, 49 (4.9%) were positive in the cysticercosis immunoblot assay. Seropositivity increased with age and reached a peak in subjects aged 46-55 years (P < 0.05). A history of seizures was significantly associated with seropositivity (P < 0.05); approximately 25% of persons with such histories were seropositive. Histories of headache, dizziness, trembling, blurred vision, and vomiting were also significantly associated with positive immunoblot assays. This study has demonstrated previously undiagnosed morbidity associated with T. solium neurocysticercosis and identified community behavioural and environmental practices that must be modified to prevent continued transmission of cysticercosis and taeniasis.

Adolescent↗
PubMedDate not supplied

Mass treatment against human taeniasis for the control of cysticercosis: a population-based intervention study.

An intervention study with mass treatment against taeniasis to prevent neurocysticercosis due to Taenia solium in a rural community in Mexico was performed in 1991-96. Information and biological samples were obtained at the beginning of the study, at 6 months and at 42 months after mass treatment with praziquantel at a single dose of 5 mg/kg. Prevalence rates of taeniasis were measured by the detection of Taenia coproantigens and Taenia eggs in faeces; neurocysticercosis was suggested by clinical data and by serum antibodies in humans and also in swine. A reduction of 53% after 6 months and of 56% after 42 months for human taeniasis was seen after treatment. Late-onset general seizures decreased 70%. Anti-cysticercus antibodies in the human population were reduced by 75% after 42 months. Antibodies in pigs also showed a significant reduction of 55% after 6 months. In conclusion, an impact of mass chemotherapy against taeniasis to control cysticercosis in the short and long term was demonstrated. Praziquantel for tapeworm treatment should not be given at doses lower than 10 mg/kg. Late-onset convulsive crisis and specific antibodies are good indicators of neurocysticercosis and of exposure to the parasite, respectively.

Adolescent↗
PubMedDate not supplied

Evagination of Taenia solium cysticerci: a histologic and electron microscopy study.

BACKGROUND: After a human being ingests a cysticercus, the larval stage of Taenia solium, the cysticercus gradually develops toward the adult parasite. In this paper, we describe the sequential progress of evagination of cysticerci. METHODS: Intact cysticerci were obtained from swine muscle, and incubated in bovine bile to stimulate evagination. Dissecting, light, and electron microscopy of whole parasites and histologic sections were used for photographic registers. RESULTS: The first event was the widening of the opening of the bladder wall for the scolex and neck to emerge. The two chambers that conform the cysticercus were identified. Histologic sections provided explanation for the conformation of the spiral canal. The scolex uncoils during evagination but does not turn inside out. CONCLUSIONS: The scolex and the neck comprise a different structure from the bladder wall, although they are contiguous.

Animals↗
PubMedDate not supplied

Hygiene and restraint of pigs is associated with absence of Taenia solium cysticercosis in a rural community of Mexico.

OBJECTIVE: To determine the prevalence and risk factors associated to pig cysticercosis in a rural community of Veracruz, Mexico. MATERIAL AND METHODS: Swine cysticercosis was diagnosed by tongue palpation and circulating antibodies in pigs kept in 178 household backyards. Risk factors were assessed by interviewing owners to collect information on pig breeding conditions and demographic characteristics. RESULTS: None of the 53 pigs studied showed cysts in the tongue, nor antibodies against Taenia solium in Western blot assays. Latrines were available in 91% of the houses and pigs were kept in restrained areas. CONCLUSIONS: The present study shows that pig breeding under restraint with basic hygiene and sanitary conditions, may be effective and practical interventions to restrain Taenia solium in rural communities.

Animals↗