Avaliação sorológica de imunização contra o sarampo com duas doses administradas aos 6 e 11 meses de idade: estudo prospectivo

A eficácia sorológica de um esquema de vacinação contra o sarampo empregando duas doses da vacina BIKEN CAM 70, sendo a primeira dose administrada aos 6 meses de idade e a segunda aos 11 meses de idade foi avaliada através de um estudo prospectivo. A amostra de sangue foi colhida entre 6 e 12 meses (média de 8,0 ± 1,7 meses) após a segunda dose da vacina, tendo-se empregado para pesquisa de anticorpos específicos a reação de imunofluorescência indireta (RIFI) e a técnica imunoenzimática ELISA. Anticorpos para o sarampo na amostra de sangue pós-vacinal foram detectados em 88,5% (85/96) das crianças quando foi empregada a RIFI e em 96,8% (93/96) quando se empregou a técnica imunoenzimática ELISA. Nenhuma das crianças apresentou, durante o período do estudo, quadro clínico compatível com sarampo. Em regiões em que uma proporção significativa de casos ocorrem antes dos 9 meses de idade, o esquema de vacinação de 2 doses, a primeira aos 6 e a segunda aos 11 meses de idade, pode representar alternativa válida para o controle do sarampo.

In vitro action of some disinfectants on Paracoccidioides brasiliensis yeast forms

The fungicidal action of sodium hypochlorite (0.3, 1, 2.5, 5 and 10%); formaldehyde (2, 5, and 10%); and ethyl alcohol (70%) on yeast forms of Paracoccidioides brasiliensis Pb 18 and a newly-isolated Goiana strain was described. Contact between the fungus and the disinfectants was maintained for 1, 2, 24, 48 and 72 hours at room temperature. Viability was evaluated by the fluorescein diacetate-ethidium bromide treatment, culture in solid and liquid media (36ºC and 26ºC); yeast to mycelial germination at room temperature; and radiometric study of metabolic activity. All concentrations of disinfectants were found to be effective in inactivating Pb 18 and Goiana strains, except for the 1-hour contact with 2% formaldehyde, in which fluorescein diacetate-ethidium bromide treatment was found to reveal 40 and 27% of viable cells, respectively. The yeast to mycelial germination method was considered to reveal faster and similar results as compared to culture in solid and liquid media.

Immunomodulatory effect of cimetidine on the proliferative responses of splenocytes from T. cruzi-infected rats

The immunomodulatory effect of cimetidine (CIM), a histamine type-2 receptor antagonist, was evaluated in respect to the blastogenic response to Con A of Wistar Furth (WF) rats infected by the Y strain of Trypanosoma cruzi (T. cruzi). Enhancement of blastogenesis of normal splenocytes was observed at a concentration of 10-3M. However, the splenocytes from infected animals responded to concentrations of CIM ranging from 10-8 to 10-3M. The mitogenic response to Con A of cells from infected animals was restored in the presence of CIM. The results show that CIM modulates the "in vitro" proliferative response of cells from T. cruzi-infected rats and suggest an immunoregulatory role of histamine and/or of cells that express H2 receptors in this infection.

Gelatin particle indirect agglutination test for serodiagnosis of schistosomiasis: comparative study with enzyme-linked immunosorbent assay

A new serological test, the gelatin particle agglutination test (GPAT), was used for the serodiagnosis of schistosomiasis mansoni. This technique showed the sensitivity (90.6%) and specificity (97.8%) close to those of enzyme-linked immunosorbent assay. The GPAT can be easily and rapidly performed without specialized equipment, by using lyophilized antigen-coated gelatin particles. The test also seems to be useful for mass screening of Schistosoma infection in field conditions.

Bacterial agents isolated from cerebrospinal fluid of patients with Acquired Immunodeficiency Syndrome (AIDS) and neurological complications

Cerebrospinal fluid (CSF) samples from 2083 patients with acquired immunodeficiency syndrome (AIDS) and neurological complications were bacteriologically examined during a period of 7 years (1984-1990). The percentage of patients who had at least one bacterial agent cultured from the CSF was 6.2%. Mycobacterium tuberculosis was the most frequently isolated agent (4.3%), followed by Mycobacterium avium complex or MAC (0.7%), Pseudomonas spp (0.5%), Enterobacter spp (0.4%), and Staphylococcus aureus (0.3%). Among 130 culture positive patients, 89 (68.5%) had M. tuberculosis and 15 (11.6%) had MAC. The frequency of bacterial isolations increased from 1988 (5.2%) to 1990 (7.2%), partly due to the increase in MAC isolations. Bacterial agents were more frequently isolated from patients in the age group 21-30 years and from women (p<0.05).

Prevalence of intestinal parasitic infection in five farms in Holambra, São Paulo, Brazil

A parasitological survey was carried out on 222 inhabitants of five farms in Holambra, located 30 km north of Campinas, São Paulo, Brazil, on October 1992. Approximately 70% of the inhabitants were found to be infected with at least one species of intestinal parasite. The positive rates of 6 helminths and 7 protozoan species detected are as follows: 5.4% Ascaris lumbricoides; 8.6% Trichuris trichiura; 19.8% Necator americanus; 10.4% Strongyloides stercoralis; 14% Enterobius vermicularis; 0.9% Hymenolepis nana; 3.2% Entamoeba histolytica; 2.7% E. hartmanni; 9.9% E. coli; 14.0% Endolimax nana; 2.3% Iodamoeba butschlii; 10.4% Giardia lamblia; 37.8% Blastocystis hominis. The positive rates of helminth infection were generaly higher in the younger-group under 16 years-old than those in the elder group aged 16 or more, whereas the infection rates of protozoan species were higher in the elder group. The infection rate of Strongyloides was found to be 10.4% by a newly developed sensitive method (an agarplate culture methods).

Serodiagnosis of strongyloidiasis. The application and significance

Parasitological diagnosis based on the faecal examination is frequently difficult in cases of chronic, low-level S. stercoralis infection. Even when a newly developed sensitive method (an agar plate culture) is applied, it is essential to examine faecal samples repeatedly to achieve a correct diagnosis. Additionally, it is important to note that a negative result does not necessarily indicate the unequivocal absence of the infection. On the other hand, several serological tests which have recently been developed for strongyloidiasis have proven reliable when used to complement parasitological examination. We have developed two serological tests, ELISA and GPAT, to demonstrate Strongyloides infection and possible applications of the serological tests for diagnosis, mass-screening, epidemiological study and postchemotherapy evaluation of strongyloidiasis were reviewed based on our recent studies.

Studies on prevalence of Strongyloides infection in Holambra and Maceió, Brazil, by the agar plate faecal culture method

Prevalence of Strongyloides stercoralis infection in three areas of Brazil was surveyed by a recently developed faecal culture method (an agar plate culture). The Strongyloides infection was confirmed in 11.3% of 432 subjects examined. The diagnostic efficacy of the agar plate culture was as high as 93.9% compared to only 28.5% and 26.5% by the Harada-Mori filter paper culture and faecal concentration methods, when faecal samples were examined simultaneously by these three methods. Among the 49 positive samples, about 60% were confirmed to be positive only by the agar plate culture. These results indicate that the agar plate culture is a sensitive new tool for the correct diagnosis of chronic Strongyloides infection.

ANALYSIS OF Treponema pallidum RECOMBINANT ANTIGENS FOR DIAGNOSIS OF SYPHILIS BY WESTERN BLOTTING TECHNIQUE

Three GST fusion recombinant antigen of Treponema pallidum, described as GST-rTp47, GST-rTp17 and GST-rTp15 were analyzed by Western blotting techniques. We have tested 53 serum samples: 25 from patients at different clinical stages of syphilis, all of them presenting anti-treponemal antibody, 25 from healthy blood donors and three from patients with sexually transmitted disease (STD) other than syphilis. Almost all samples from patients with syphilis presented a strong reactivity with GST-rTp17 antigen. Some samples were non-reactive or showed a weak reaction with GST-rTp47 and/or GST-rTp15, and apparently there was no correlation with the stage of disease. There was no seropositivity among blood donors. No sample reacted with purified GST. We concluded that due to their specificity these recombinant antigens can be used as GST fusion protein for development of syphilis diagnostic assays.

Hepatitis B vaccine in infants: a randomized controlled trial comparing gluteal versus anterolateral thigh muscle administration

A significantly diminished antibody response to hepatitis B vaccine has been demonstrated in adults when the buttock is used as the injection site. However, in Brazil, the buttock continues to be recommended as site of injection for intramuscular administration of vaccines in infants. In this age group, there are no controlled studies evaluating the immunogenicity of the hepatitis B vaccine when administered at this site. In the present study, 258 infants were randomized to receive the hepatitis B vaccine either in the buttock (n = 123) or in the anterolateral thigh muscle (n = 135). The immunization schedule consisted of three doses of hepatitis B vaccine (Engerix Bâ, 10 mug) at 2, 4 and 9 months of age. There were no significant differences in the proportion of seroconversion (99.3% x 99.2%), or in the geometric mean titer of ELISA anti-HBs (1,862.1 x 1,229.0 mIU/mL) between the two groups. This study demonstrates that a satisfactory serological response can be obtained when the hepatitis B vaccine is administered intramuscularly into the buttock.

Assessment of the rapid test based on an immunochromatography technique for detecting anti-Treponema pallidum antibodies

A rapid test based on an immunochromatography assay - Determine™ Syphilis TP (Abbott Lab.) for detecting specific antibodies to Treponema pallidum was evaluated against serum samples from patients with clinical, epidemiological and serological diagnosis of syphilis, patients with sexually transmitted disease other than syphilis, and individuals with negative serology for syphilis. The Determine™ test presented the sensitivity of 93.6%, specificity of 92.5%, and positive predictive value and negative predictive value of 95.2% and 93.7%, respectively. One serum sample from patient with recent latent syphilis showed a prozone reaction. Determine™ is a rapid assay, highly specific and easy to perform. This technique obviates the need of equipment and its diagnostic features demonstrate that it may be applicable as an alternative assay for syphilis screening under some emergency conditions or for patients living in remote localities.

Intranasal sensitization with Blomia Tropicalis antigens induces allergic responses in mice characterized by elevated antigen-specific and non-specific serum ige and peripheral blood eosinophil counts

In order to evaluate the potential allergenicity of Blomia tropicalis (Bt) antigen, IgE production of both specific and non-specific for Bt antigen was monitored in BALB/c mice after exposure to the antigen by nasal route. It was evidenced that B. tropicalis contains a functional allergen in its components. The allergenic components, however, when administered intranasally without any adjuvant, did not function to induce IgE response within a short period. On the other hand, intranasal inoculation of Bt antigens augmented serum IgE responses in mice pretreated by a subcutaneous priming injection of the same antigens. Inoculation of Bt antigen without subcutaneous priming injections induced IgE antibody production only when the antigen was continuously administered for a long period of over 24 weeks. Even when the priming injection was absent, the Bt antigen inoculated with cholera toxin (CT) as a mucosal adjuvant also significantly augmented the Bt antigen-specific IgE responses depending on the dose of CT co-administered. The present study also demonstrated that Bt antigen/CT-inoculated mice showed increased non-specific serum IgE level and peripheral blood eosinophil rates without noticeable elevations of the total leukocyte counts. The immunoblot analysis demonstrated 5 main antigenic components reactive to IgE antibodies induced. These components at about 44-64 kDa position were considered to be an important candidate antigen for diagnosis of the mite-related allergy.

Pathogenicity of different rabies virus isolates and protection test in vaccinated mice

This study was aimed to evaluate and compare the pathogenicity of rabies virus isolated from bats and dogs, and to verify the efficacy of a commercial rabies vaccine against these isolates. For evaluation of pathogenicity, mice were inoculated by the intramuscular route (IM) with 500MICLD50/0.03mL of the viruses. The cross-protection test was performed by vaccinating groups of mice by the subcutaneous route and challenged through the intracerebral (IC) route. Isolates were fully pathogenic when inoculated by the IC route. When inoculated intramuscularly, the pathogenicity observed showed different death rates: 60.0% for the Desmodus rotundus isolate; 50.0% for dog and Nyctinomops laticaudatus isolates; 40.0% for Artibeus lituratus isolate; 9.5% Molossus molossus isolate; and 5.2% for the Eptesicus furinalis isolate. Mice receiving two doses of the vaccine and challenged by the IC route with the isolates were fully protected. Mice receiving only one dose of vaccine were partially protected against the dog isolate. The isolates from bats were pathogenic by the IC route in mice. However, when inoculated through the intramuscular route, the same isolates were found with different degrees of pathogenicity. The results of this work suggest that a commercial vaccine protects mice from infection with bat rabies virus isolates, in addition to a canine rabies virus isolate.

Detecção de riquétsias em carrapatos do gênero Amblyomma (Acari: Ixodidae) coletados em parque urbano do município de Campinas, SP

O Município de Campinas situa-se em região endêmica para febre maculosa brasileira do Estado de São Paulo, onde vários casos desta doença vem ocorrendo. Capivaras têm sido associadas ao ciclo dessa riquetsiose por apresentarem sorologia positiva e serem hospedeiras de carrapatos Amblyomma spp principais vetores da doença. Carrapatos foram coletados no parque urbano do Lago do Café, Campinas, SP, local associado a casos humanos suspeitos de febre maculosa brasileira, sobre a vegetação e das capivaras ali presentes, e pesquisados quanto à presença de riquétsias pela reação em cadeia da polimerase e pelo teste de hemolinfa. Adultos de Amblyomma cajennense e Amblyomma cooperi albergavam Rickettsia bellii, não patogênica, identificada pela análise das seqüências de nucleotídeos do gene gltA, porém, não foram constatadas riquétsias do Grupo da Febre Maculosa. Estes resultados associados à ausência de um isolado de riquétsias do Grupo da Febre Maculosa de capivaras indicam que seu papel, enquanto reservatório, necessita de maior investigação.

Physicochemical properties and antioxidant capacity of propolis of stingless bees (Meliponinae) and Apisfrom two regions of Tocantins, Brazil

ABSTRACTThe composition of propolis depends on time, vegetation and the location of the collection area. The objective of this study was to determine the physicochemical characteristics, the concentration of phenol compounds and the antioxidant capacity of propolis of native stingless bees (Meliponinae)and Apis from the State of Tocantins. Extraction with 80% ethanol (v/v) was performed in order to obtain the extracts. Parameters examined were: propolis mass loss by desiccation at 105 ºC, ashes, wax concentration and pH. Furthermore, the propolis antioxidant activity was measured, as well as the total concentration of phenol compounds. The extracts were also analyzed by high performance liquid chromatography. The total concentration of phenol compounds varied between 121.78 and 631.29 (mg GAE g-1). The antioxidant activity expressed by the value of CE50 varied between 29.81 and 845.38 µg mL-1. High performance liquid chromatography analysis allowed us to infer the existence of phenol compounds. The results indicated that the studied propolis samples constitute good sources of natural antioxidants. The variety of phenol compounds identified in this study, and the diverse biological functions reported in literature for these compounds indicated that this stingless bee propolis (Meliponinae) and Apis has a high pharmacological potential.