Simplification of Immune Adherence Hemagglutination test for detection of rabies antibodies in human serum

In the present work the immune adherence hemagglutination test (IAHA) was standardized in a simplified procedure. This test showed good reproducibility, better than the classical mice serum neutralization test (SN). The tests showed high correlation degree: high titers in one test corresponded to high titers in the other one, and the same occured with low titers. The IAHA test is extremely simple, fast to perform, and of low cost when compared to tests such as SN or indirect immunofluorescense (IIF). It also proved to be useful in less sophisticated laboratories or even as a screening test for the titration of rabies antibodies.

Evaluation of enzyme-linked immunosorbent and alternative assays for detection of HIV antibodies using panels of Brasilian sera

Sera from 472 Brazilian subjects, confirmed to be either positive or negative for HIV antibodies and comprising the total clinical spectrum of HIV infection, were utilized in the evaluation of six commercially available enzyme-linked immunosorbent assays (ELISA), as well as of four alternative assays, namely indirect immunofluorescence (IIF), passive hemagglutination (PHA), dot blot and Karpas AIDS cell test. The sensitivities ranged from 100% (Abbott and Roche ELISA) to 84.2% (PHA) and the specificities ranged from 99.3% (IIF) to 80.2% (PHA). The sensitivity and specificity of the PHA and the sensitivity of the Karpas cell test were significantly lower than those of the other tests. Although the IFF and dot blot had good sensitivities and specificities, the six ELISA were more attractive than those tests when other parameters such as ease of reading and duration of assay were considered.

Chagas' disease: IgA, IgM and IgG antibodies to T. cruzi amastigote, trypomastigote and epimastigote antigens in acute and in different chronic forms of the disease

In an attempt to find a better T. cruzi antigen and possible immunological markers for the diagnosis of different clinical forms of Chagas' disease, amastigote and trypomastigote antigens obtained from immunosuppressed mice infected with T. cruzi (Y strain) were assessed in comparison with conventional epimastigote antigens. A total of 506 serum samples from patients with acute and with chronic (indeterminate, cardiac and digestive) forms, from nonchagasic infections, and from healthy individuals were assayed in immunofluorescence (IF) tests, to search for IgG, IgM and IgA antibodies. Amastigote proved to be the most convenient antigen for our purposes, providing higher relative efficiency indexes of 0.946, 0.871 and 0.914 for IgG, IgM and IgA IF tests, respectively. Anti-amastigote antibodies presented higher geometric mean titers (GMT) than anti-trypomastigote and anti-epimastigote. Anti-amastigote IgG antibodies were found in all forms of Chagas' disease, and predominantly IgA antibodies, in chronic digestive and in acute forms, as well as IgM antibodies, in latter forms. Thus, tests with amastigote antigen could be helpful for screening chagasic infections in blood banks. Practical and economical aspects in obtaining amastigotes as here described speak in favour of its use in developing countries, since those from other sources require more complex system of substruction, specialized personnel or equipment.

Relationship between the prevalence of antibodies to hepatitis B core antigen and arbovirus in fishermen from the Ribeira Valley, Brazil

Sera from 299 fishermen 16 to 80 years old, residents in Cananeia and Iguape counties, southern cost of São Paulo State, Brazil, were studied in order to identify a possible association between the prevalence of specific antibodies to the hepatitis B virus (HBV) and exposure to haematophagus mosquitoes evaluated by the prevalence of arbovirus antibodies. This professional group presented the highest prevalence of arbovirus antibodies (54.1%) in past investigations carried out in this heavily forested region. Detection of antibody to hepatitis B core antigen (anti-HBc) in the sera was done by enzyme immunoassay (Roche). Prevalence of anti-HBc antibodies in this group was 31.4% (94/299) which is very high compared with 7.2% to 15.0% for different groups of healthy adults in State of São Paulo. No significant difference is observed between the prevalences of HBV antibodies in Iguape and Cananeia. Prevalence of anti-HBc and anti-arbovirus antibodies increases with age. There is a concordance in the distribution according to age groups of the frequency of anti-HBc and anti-arbovirus positive sera. Ag HBs was detected in 4% of the studied sera. These results support the hypothesis that the transmission of the hepatitis B virus and the arboviruses may be due to the same factor, one of the possibilities would be by anthropophilic mosquitoes.

Lymphocyte subpopulations and neutrophil function in chronic human Chagas' disease

The absolute numbers of total leukocytes, lymphocytes, T cells, helper/inducer, suppressor/cytotoxic and B cells were decreased in the peripheral blood of patients with chronic Chagas' disease. Since antilymphocyte antibodies were present only in a minority of patients they probably cannot account for the abnormalities in lymphocyte subsets. Patient neutrophils stimulated with endotoxin-treated autologous plasma showed depressed chemotactic activity and this seems to be an intrinsic cellular defect rather than plasma inhibition. Random migration of neutrophils was normal. Reduction of nitroblue tetrazolium by endotoxin- stimulated neutrophils was also decreased. These findings further document the presence of immunosuppression in human Chagas' disease. They may be relevant to autoimmunity, defense against microorganisms and against tumor cells at least in a subset of patients with more severe abnormalities.

DOT-ELISA for detection of anti-Cysticercus cellulosae antibodies in human cerebrospinal fluid using a new solid-phase (resin-treated polyester fabrics): preliminary report

A dot enzyme-linked immunosorbent assay (DOT-ELISA) was developed to detect specific antibodies in cerebrospinal fluid (CSF) for human neurocysticercosis immunodiagnosis, with Cysticercus cellulosae antigen dotted on a new solid-phase. This was represented by sheets of a synthetic polyester fabric impregnated with a polymerized resin (N-methylol-acrylamide). A very stable preparation was thus obtained, the antigen being covalently bound by cross-linking with free N-methylol groups on the resin. Since robust, no special care was necessary for handling the solid-phase. The test could be performed at room-temperature. From 30 CSF samples assayed, 14 were positive, from a group of 15 cases of neurocysticercosis, with titers from 1 to 128; 15 other samples, from normals or other neurological diseases, were all negative. Test characteristics seem to indicate it as adequate for epidemiological surveys. A more detailed study on sensitivity, specificity, reproducibility and the use in serum samples is being conducted.

Comparison of indirect immunofluorescence test for measles antibodies with haemagglutination inhibition and plaque neutralization tests

Indirect Immunofluorescence (IFA), Plaque Reduction Neutralization (PRN) and Haemagglutination Inhibition (HI) tests for measles antibodies were carried out in 197 sera obtained from umbilical cord and vaccinated children. The IFA was also applied to blood samples collected with filter paper. IFA results demonstrated that the test is relatively simple to perform, with good reproducibility for different antigen lots. Good correlation was obtained between IFA, PRN and HI antibody titers. Better correlation was demonstrated with IFA and PRN than with HI and PRN tests. Sensitivity of IFA in detecting antibody was less effective than PRN, however more effective than HI using rhesus monkey red blood cells. PRN antibody titers over 100 were detected by IFA but not by HI (9.7% with negative results). IFA may be of considerable practical use and able to substitute HI in Seroepidemiological surveys and to evaluate vaccine efficacy. It also can be simplified by employing filter paper collected samples.

Efeitos de imunopotenciadores não específicos na infecção experimental pelo Schistosoma mansoni: I. levamisole

Os efeitos do levamisole nas alterações histopatológicas, resistência do hospedeiro e quimiotaxia "in vivo" foram estudados na infecção experimental pelo Schistosoma mansoni em camundongos da linhagem C57B1/10. O tratamento profilático resultou em um aumento no número de vermes adultos obtidos pela perfusão e também em uma taxa de mortalidade maior (p < 0,05). As alterações histopatológicas (fígado e intestino) foram similares em todos os grupos. Uma redução significante da quimiotaxia "in vivo" ocorreu em camundongos controles infectados, assim como naqueles submetidos a tratamento profilático com levamisole. A atividade quimiotática atingiu os mesmos níveis dos camundongos controles normais (não-infectados e não-tratados com levamisole), quando o esquema curativo foi usado. O levamisole parece aumentar a susceptibilidade de camundongos da linhagem C57B1/10 à infecção pelo S. mansoni quando administrado antes da infecção e normaliza a atividade quimiotática, quando dado após a infecção.

Deep crustal structure across a young passive margin from wide-angle and reflection seismic data (The Sardinia Experiment) - I. Gulf of Lion's margin

The conjugate margins system of the Gulf of Lion and West Sardinia (GLWS) represents a unique natural laboratory for addressing fundamental questions about rifting due to its landlocked situation, its youth, its thick sedimentary layers, including prominent palaeo-marker such as the MSC event, and the amount of available data and multidisciplinary studies. The main goals of the SARDINIA experiment, were to (i) investigate the deep structure of the entire system within the two conjugate margins: the Gulf of Lion and West Sardinia, (ii) characterize the nature of the crust, and (iii) define the geometry of the basin and provide important constrains on its genesis. This paper presents the results of P-wave velocity modelling on three coincident near-vertical reflection multi-channel seismic (MCS) and wide-angle seismic profiles acquired in the Gulf of Lion, to a depth of 35 km. A companion paper [part II Afilhado et al., 2015] addresses the results of two other SARDINIA profiles located on the oriental conjugate West Sardinian margin. Forward wide-angle modelling of both data sets confirms that the margin is characterised by three distinct domains following the onshore unthinned, 33 km-thick continental crust domain: Domain I is bounded by two necking zones, where the crust thins respectively from 30 to 20 and from 20 to 7 km over a width of about 170 km; the outermost necking is imprinted by the well-known T-reflector at its crustal base; Domain II is characterised by a 7 km-thick crust with anomalous velocities ranging from 6 to 7.5 km/s; it represents the transition between the thinned continental crust (Domain I) and a very thin (only 4-5 km) "atypical" oceanic crust (Domain III). In Domain II, the hypothesis of the presence of exhumed mantle is falsified by our results: this domain may likely consist of a thin exhumed lower continental crust overlying a heterogeneous, intruded lower layer. Moreover, despite the difference in their magnetic signatures, Domains II and III present the very similar seismic velocities profiles, and we discuss the possibility of a connection between these two different domains.

Schistosomiasis mansoni in an area of low transmission: I. impact of control measures

This work was undertaken in the municipality of Pedro de Toledo (São Paulo State, Brazil) in 1987, to clarify aspects related to the transmission levels of Schistosoma mansoni in a human population where the snail host is Biomphalaria tenagophila. Since 1980 a control programme has been undertaken in this municipality. Urban and rural populations (4,719 subjects) were submitted to faecal examinations (Kato-Katz method). The overall prevalence rate was 4.8% being higher in males (6.2%) and also in the rural zone (5.8%). The geometric mean of S. mansoni eggs was 35.1 eggs per gramme of faeces (epg). Approximately 80.0% of the carriers presented less than 100 epg and only 20 individuals (9.0%) eliminated more than half of total eggs. The highest index of potencial contamination (IPC) was in the age group of 5 to 20 years (57.6%). Two thirds of the investigated patients (207) were autochthonous of Pedro de Toledo. The geographical distribution of the carriers showed a clear aggregation of the autochthonous cases and a close association between human contact sites and breeding places of B. tenagophila. This study shows that schistosomiasis subjects were not randomly aggregated, the youngsters should be the main target in the prophylaxis, and the efficacy of the control programme.

E.L.I.S.A. en coccidioidomicosis humana

Se realizó E.L.I.S.A. con exoantígeno de Coccidioides immitis para la detectión de anticuerpos, en 67 sueros humanos diluidos 1/1000, 1/2000, 1/4000 y 1/8000. De los 18 sueros de enfermos de coccidioidomicosis comprobada por examen directo, cultivo y/o histología, 5 fueron negativos, en otros 13 fueron positivos en una o varias diluciones. 3/26 sueros de personas sanas, coccidioidino positivas, fueron positivos en títulos de 1/1000 y el resto no tuvo anticuerpos detectables. No presentaron reacciones positivas ninguno de los sueros controles de personas sanas, pero sí lo hicieron 4/8 pacientes con otras micosis. Se concluye que E.L.I.S.A. es útil para la detección de mínimas cantidades de anticuerpos o en sueros que no pueden ser procesados por fijación de complemento. No es recomendable el uso de la técnica en forma aislada por al presencia de reacciones cruzadas.

Antibodies against Entamoeba histolytica in individuals with intestinal amoebiasis presenting cysts and/or trophozoites in the feces

Serum samples were obtained from 154 individuals infected with Entamoeba histolytica (78 symptomatic and 76 asymptomatic). Twelve had trophozoites in the feces whereas 142 had only cysts. The sera were used to test the existence of antibodies anti-Entamoeba histolytica employing the Indirect Hemagglutination (IHA), Indirect Immunofluoresccnce (IFAT), Complement Fixation Reaction (CFR) and Counterimmunoelectrophoresis (CIEP). For those individuals with trophozoites in their feces, 75.0 were positive by IHA and IFAT, 83.0 by CFR and 41.7 by CIEP. In individuals who had only cysts, positive results by the same tests were respectively, 5.6%, 12.0%, 19.0% and 5.6%. The difference in relation to the tilers of antibodies detected through IHA, IFAT, CFR and CIEP and in relation to the presence of trophozoites or cysts in the feces was significative for four immunological reactions when X², was employed (P < 0.05).

D. Fernando I, 2º Duque de Bragança: vida e acção política

Dissertação apresentada para cumprimento dos requisitos necessários à obtenção do grau de Mestre em História Medieval.