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.

Determination du niveau d'anticorps antitetaniques en donneurs de sang au moyen du test ELISA-TÉTANOS (São Paulo, SP, Bresil)

Le test ELISA-TÉTANOS (Biosys, France) a été utilisé pour le titrage des anti-corps tétaniques (sensibilité = 0,0025 UI/ml) en sérums humains de donneurs de sang, 566 hommes et 108 femmes, âges de 18 à 58 ans, moyenne de 29 ans, provenant de São Paulo, SP, Brésil. L'OMS, acceptant seulement la séroneutralisation sur souris (NT), la méthode de référence, pour les études sur la protection contre le tétanos, préconise le titre de 0,01 UI/ml comme minimum protecteur. BOURLEAUD & HUET ont proposé la limite de 0,06 UI/ml quand s'emploie le test ELISA, en attendant à une certaine discordance inévitable entre les méthodes. Parmi les 674 sérums étudiés, 178 (26,41%) n'ont pas présenté d'anticorps (< 0,0025 UI/ml); 413 (61,28%) ont présenté des résultats égaux ou supérieurs à 0,01 UI/ml et en 232 (34,42%) les titres ont été égaux ou supérieurs à 0,06 UI/ml. Le pourcentage d'individus protégés a été inversement proportionnel à 1'âge: environ 50% dans le groupe le plus jeune (hommes de 18 à 35 ans et femmes de 18 à 23 ans) contre environ 10% dans le groupe de plus de 42 ans ont présenté des titres sûrement protecteurs (> 0,06 UI/ml).

Diagnosis of Helicobacter pylori: comparison of an urease test, histological visualization of curved bacteria and culture

Helicobacter pylori was investigated in 189 patients for culture, microscopic visualization of campylobacter-like organisms (CLO) and a ten minute urease test. In 136 (72%) the bacteria was isolated, and in 98 of them CLO were histologically detected. Specificity, sensitivity, positive and negative predictive values of microscopic visualization of CLO were: 0.77, 0.73, 0.97 and 0.51, respectively; 98 culture-positive patients were urease test positive. Specificity, sensitivity, positive and negative predictive values of the urease test were: 0.83, 0.72, 0.92 and 0.54, respectively. Comparing the urease test with culture of H. pylori combined with microscopic visualization of CLO, its specificity, sensitivity, positive and negative predictive values were: 0.95, 0.71, 0.98 and 0.48, respectively. Probably, these values are not real, since bacteria different from H. pylori could be misclassified as CLO.

Comparison on the performance of Leishmania major-like and Leishmania braziliensis braziliensis as antigen for new world leishmaniasis IgG-immunofluorescence test

The performance of an antigen of L. major-like promastigotes for the serological diagnosis of mucocutaneous leishmaniasis in the IgG-immunofluorescent test was compared to that of an antigen of L. braziliensis braziliensis. Each antigen was used to test two hundred and twenty-four sera of etiologies such as mucocutaneous leishmaniasis, deep mycoses, toxoplasmosis, malaria, Chagas' disease, visceral leishmaniasis, anti-nuclear factor, schistosomaiasis, rheumatoid factor and normal controls. Agreement between responses to each antigen was high: 77.2% of leishmaniases sera agreed on a positive or a negative result to both antigens and 91.1 % of control sera. Cross reactivity was restricted to Chagas' disease sera, visceral leishmaniasis, anti-nuclear factor and paracoccidiodomycosis. The quantitative response of leishmaniasis and Chagas' disease sera to both antigens was evaluated by a linear regression; although the y-intercept and the slope were different for each antigen, neither was better than the other in the disclosure of anti-Leishmania antibodies. In the case of Chagas' disease sera the L. major-like antigen was better than L. b. braziliensis' to disclose cross-reacting antibodies.

Evaluation of temporal, seasonal and geographic stability of the molluscicidal property of Euphorbia splendens latex

Laboratory tests with aqueous solutions of Euphorbia splendens var. hislopii latex have demonstrated seasonal stability of the molluscicidal principle, with LD90 values of 1.14 ppm (spring), 1.02 ppm (fall), 1.09 ppm (winter), and 1.07 ppm (summer) that have been determined against Biomphalaria tenagophila in the field. Assays on latex collected in Belo Horizonte and Recife yielded LD90 values similar to those obtained with the reference substance collected in Rio de Janeiro (Ilha do Governador), demonstrating geographic stability of the molluscicidal effect. The molluscicidal action of aqueous dilutions of the latex in natura, centrifuged (precipitate) and lyophilized, was stable for up to 124 days at room temperature (in natura) and for up to 736 days in a common refrigerator at 10 to 12ºC (lyophilized product). A 5.0 ppm solution is 100% lethal for snails up to 13 days after preparation, the effect being gradually lost to almost total inactivity by the 30th day. This observation indicated that the active principle is instable. These properties together with the wide distribution of the plant, its resistance and adaptation to the tropical climate, its easy cultivation and the easy obtention of latex and preparation of the molluscicidal solution, make this a promising material for large-scale use in the control of schistosomiasis

Fresh-cut aromatic herbs: Nutritional quality stability during shelf-life

Fresh-cut vegetables are a successful convenient healthy food. Nowadays, the presence of new varieties of minimally processed vegetables in the market is common in response to the consumers demand for new flavours and high quality products. Within the most recent fresh-cut products are the aromatic herbs. In this work, the objective was to evaluate the nutritional quality and stability of four fresh-cut aromatic herbs. Several physicochemical quality characteristics (colour, pH, total soluble solids, and total titratable acidity) were monitored in fresh-cut chives, coriander, spearmint and parsley leaves, stored under refrigeration (3 ± 1 ºC) during 10 days. Their nutritional composition was determined, including mineral composition (phosphorous, potassium, sodium, calcium, magnesium, iron, zinc, manganese and copper) and fat- and water-soluble vitamin contents. Total soluble phenolics, flavonoids and the antioxidant capacity were determined by spectrophotometric methods. The aromatic herbs kept their fresh appearance during the storage, maintaining their colour throughout shelf-life. Their macronutrient composition and mineral content were stable during storage. Coriander had the highest mineral and fatsoluble vitamin content, while spearmint showed the best scores in the phenolic, flavonoid and antioxidant capacity assays. Vitamins and antioxidant capacity showed some variation during storage, with a differential behaviour of each compound according to the sample.

Dynamical Stability and Predictability of Football Players: The Study of One Match

The game of football demands new computational approaches to measure individual and collective performance. Understanding the phenomena involved in the game may foster the identification of strengths and weaknesses, not only of each player, but also of the whole team. The development of assertive quantitative methodologies constitutes a key element in sports training. In football, the predictability and stability inherent in the motion of a given player may be seen as one of the most important concepts to fully characterise the variability of the whole team. This paper characterises the predictability and stability levels of players during an official football match. A Fractional Calculus (FC) approach to define a player’s trajectory. By applying FC, one can benefit from newly considered modeling perspectives, such as the fractional coefficient, to estimate a player’s predictability and stability. This paper also formulates the concept of attraction domain, related to the tactical region of each player, inspired by stability theory principles. To compare the variability inherent in the player’s process variables (e.g., distance covered) and to assess his predictability and stability, entropy measures are considered. Experimental results suggest that the most predictable player is the goalkeeper while, conversely, the most unpredictable players are the midfielders. We also conclude that, despite his predictability, the goalkeeper is the most unstable player, while lateral defenders are the most stable during the match.

Utilização de técnicas de análise fotogramétricas em quebra-mares de taludes

Dissertação de Natureza Científica elaborada no Laboratório Nacional de Engenharia Civil (LNEC) para obtenção do grau de mestre em Engenharia Civil na Área de Especialização de Hidráulica no âmbito do protocolo de cooperação entre o ISEL e o LNEC

Two-loop stability of a complex singlet extended Standard Model

Motivated by the dark matter and the baryon asymmetry problems, we analyze a complex singlet extension of the Standard Model with a Z(2) symmetry (which provides a dark matter candidate). After a detailed two-loop calculation of the renormalization group equations for the new scalar sector, we study the radiative stability of the model up to a high energy scale (with the constraint that the 126 GeV Higgs boson found at the LHC is in the spectrum) and find it requires the existence of a new scalar state mixing with the Higgs with a mass larger than 140 GeV. This bound is not very sensitive to the cutoff scale as long as the latter is larger than 10(10) GeV. We then include all experimental and observational constraints/measurements from collider data, from dark matter direct detection experiments, and from the Planck satellite and in addition force stability at least up to the grand unified theory scale, to find that the lower bound is raised to about 170 GeV, while the dark matter particle must be heavier than about 50 GeV.

Measles serodiagnosis: standardization and evaluation of a dot-ELISA

A Dot-ELISA using a measles virus (MV) antigen obtained by sodium deoxycholate treatment was standardized and evaluated for IgM and IgG antibody detection in measles patients and measles-vaccinated subjects. A total of 192 serum samples were studied, comprising 47 from patients with acute and convalescent measles, 55 from 9-month old children prior to measles vaccination and 41 from children of the same age after vaccination, and 49 from patients with unrelated diseases. The diagnostic performances of the IgG Dot-ELISA and IgG immuno fluorescence test (IFT) were found to be close, varying from 0.97 to 1.00 in sensitivity and the specificities were maximum (1.00). Nevertheless, the sensitivity of the IgM Dot-ELISA (0.85) was higher than that (0.63) of the IgM IFT, although both assays had comparably high (1.00) specificities. The IgM Dot-ELISA in particular proved to be more sensitive in relation to other assays studied by revealing antibodies in 80.0% (12/15) of vaccinated children on the 15th day after immunization. In contrast the IgM IFT, failed to detect antibodies in the same group of vaccinated children. The stability of the MV antigen was longer than that of the IFT antigen, and the reproducibility of the Dot-Elisa was satisfactory.

An evaluation of the direct agglutination test to diagnose "Mal de Caderas" disease

Se evaluó la utilidad de la prueba de aglutinación directa (AD) para diagnosticar el Mal de Caderas. Se emplearon cuarenta y cuatro sueros provenientes de dos lotes de equinos naturalmente infectados con el Trypanosoma evansi (Lote 1 y Lote 2). La AD fue positiva (Aglutinación > 1:512) en 13 de 16 equinos (81.2%), de los que se aislaron los parásitos. En doce de estos animales (92%) se detectaron IgM anti T. evansi mediante la AD realizada con 2-mercaptoetanol (AD + 2-ME). La AD fue positiva en 17 de los 28 equinos que resultaron negativos al diagnóstico parasitológico. Un tercer lote de cinco equinos infectados con T. evansi que presentaba elevados títulos de AD, fue tratado con Suramina Sódica (Nagano1-Bayer). La AD + 2-ME evidenció en cuatro animales que, gran parte de estos anticuerpos se ubicaban en la fracción IgM. Posterior al tratamiento farmacológico y, en concordancia de la negativización de la parasitemia, la detección de la IgM anti T. evansi no fue posible, mientras que los anticuerpos IgG continuaron detectándose a los doce meses post-tratamiento en valores de 1:512, en tres animales. Cincuenta sueros de equinos de una zona libre del parásito, que se emplearon como controles, fueron negativos a la AD. Se recomienda la utilización de la AD y AD + 2-ME para el uso de rutina en el diagnóstico del Mal de Caderas de los equinos, en combinación con otros métodos parasitológicos sensibles.

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.

Gammaretroviral and lentiviral vectors for gene therapy: stability and inactivation mechanisms

Dissertation presented to obtain a Ph.D degree in Engineering and Technology Sciences, Gene Therapy at the Instituto de Tecnologia Quimica e Biológica, Universidade Nova de Lisboa

Bacterial antigen detection in cerebrospinal fluid by the latex agglutination test

Eighty purulent cerebrospinal fluid (CSF) samples from patients with clinical evidence of meningitis were studied using the Directigen latex agglutination (LA) kit to determine the presence of bacterial antigen in CSF. The results showed a better diagnostic performance of the LA test than bacterioscopy by Gram stain, culture and counterimmunoelectrophoresis (CIE), as far as Neisseria meningitidis groups B and C, and Haemophilus influenzae type b are concerned, and a better performance than bacterioscopy and culture considering Streptococcus pneumoniae. Comparison of the results with those of culture showed that the LA test had the highest sensitivity for the Neisseria meningitidis group C. Comparing the results with those of CIE, the highest levels of sensitivity were detected for N. meningitidis groups B and C. Regarding specificity, fair values were obtained for all organisms tested. The degree of K agreement when the LA test was compared with CIE exhibited better K indices of agreement for N. meningitidis groups B and C.

Egg excretion in the initial phase of experimental murine schistosomiasis mansoni: stability and association with worm burden

Stability of faecal egg excretion and correlation with results related to worm burden at the initial phase of schistosomiasis mansoni were observed in two groups of mice infected with different Schistosoma mansoni cercarial burdens, by means of analysis of quantitative parasitological studies and schistosome counts after perfusion. Thus, it may be stated that few quantitative parasitological stool examinations could be sufficient to express the infection intensity at the initial phase, on the same grounds that it was already demonstrated at the chronic phase. Furthermore, it is confirmed that the use of the number of eggs passed in the faeces as a tool to estimate the worm burden at the initial phase of schistosome infection is adequate.