Comparison of polymerase chain reaction on fresh tissue samples and fecal drops on filter paper for detection of Trypanosoma cruzi in Rhodnius prolixus

PCR detection of Trypanosoma cruzi in Rhodnius prolixus using fresh tissue or fecal drops on filter paper showed comparable results: 38.7% infection rate using the fresh tissue sample and 37.9% by dried fecal drop.

Detection of the acute phase of abdominal angiostrongyliasis with a parasite-specific IgG enzyme linked immunosorbent assay

Angiostrongylus costaricensis may cause intestinal lesions of varied severity when it accidentally infects man in Central and South America. First-stage larvae have never been detected in stools. Therefore, a parasite-specific IgG ELISA was evaluated for the determination of the acute phase of infection. The specificity and the sensitivity of the immunoassay was shown to be 76.2% and 91.1%, respectively. Eight serum samples taken from patients with histopathological diagnosis, at different time points (3 to 15 months) after surgical treatment, showed a sharp and early decline in antibody reactivity. The titration of anti-A. costaricensis antibodies has proved to be a useful method for the diagnosis of acute abdominal angiostrongyliasis.

Comparison between precipitin and ELISA tests in the bloodmeal detection of Aedes aegypti (Linnaeus) and Aedes fluviatilis (Lutz) mosquitoes experimentally fed on feline, canine and human hosts

The identification of arthropod bloodmeals is important in many epidemiological studies, as, the understanding of the life cycle of vectors and the patogens they transmit, as well as helping to define arthropods' control strategies. The precipitin test has been used for decades, but ELISA is slowly becoming more popular. To compare the two tests for sensitivity, specificity and accuracy to detect small insect bloodmeals, Aedes aegypti or Ae. fluviatilis mosquitoes were fed either on feline, canine or human hosts. Mosquitoes were frozen at 6, 12, 24, 48 or 72 h after feeding. Precipitin test showed better specificity and accuracy and ELISA test showed higher sensitivity. Better results with both tests were achieved when mosquitoes were frozen within 48 h from feeding.

Detection of coronary stenoses with contrast enhanced, three-dimensional free breathing coronary MR angiography using the gadolinium-based intravascular contrast agent gadocoletic acid (B-22956).

PURPOSE: To determine the diagnostic value of the intravascular contrast agent gadocoletic acid (B-22956) in three-dimensional, free breathing coronary magnetic resonance angiography (MRA) for stenosis detection in patients with suspected or known coronary artery disease. METHODS: Eighteen patients underwent three-dimensional, free breathing coronary MRA of the left and right coronary system before and after intravenous application of a single dose of gadocoletic acid (B-22956) using three different dose regimens (group A 0.050 mmol/kg; group B 0.075 mmol/kg; group C 0.100 mmol/kg). Precontrast scanning followed a coronary MRA standard non-contrast T2 preparation/turbo-gradient echo sequence (T2Prep); for postcontrast scanning an inversion-recovery gradient echo sequence was used (real-time navigator correction for both scans). In pre- and postcontrast scans quantitative analysis of coronary MRA data was performed to determine the number of visible side branches, vessel length and vessel sharpness of each of the three coronary arteries (LAD, LCX, RCA). The number of assessable coronary artery segments was determined to calculate sensitivity and specificity for detection of stenosis > or = 50% on a segment-to-segment basis (16-segment-model) in pre- and postcontrast scans with x-ray coronary angiography as the standard of reference. RESULTS: Dose group B (0.075 mmol/kg) was preferable with regard to improvement of MR angiographic parameters: in postcontrast scans all MR angiographic parameters increased significantly except for the number of visible side branches of the left circumflex artery. In addition, assessability of coronary artery segments significantly improved postcontrast in this dose group (67 versus 88%, p < 0.01). Diagnostic performance (sensitivity, specificity, accuracy) was 83, 77 and 78% for precontrast and 86, 95 and 94% for postcontrast scans. CONCLUSIONS: The use of gadocoletic acid (B-22956) results in an improvement of MR angiographic parameters, asssessability of coronary segments and detection of coronary stenoses > or = 50%.

Interpretation of partial fingermarks using an automated fingerprint identification system

Abstract : In the subject of fingerprints, the rise of computers tools made it possible to create powerful automated search algorithms. These algorithms allow, inter alia, to compare a fingermark to a fingerprint database and therefore to establish a link between the mark and a known source. With the growth of the capacities of these systems and of data storage, as well as increasing collaboration between police services on the international level, the size of these databases increases. The current challenge for the field of fingerprint identification consists of the growth of these databases, which makes it possible to find impressions that are very similar but coming from distinct fingers. However and simultaneously, this data and these systems allow a description of the variability between different impressions from a same finger and between impressions from different fingers. This statistical description of the withinand between-finger variabilities computed on the basis of minutiae and their relative positions can then be utilized in a statistical approach to interpretation. The computation of a likelihood ratio, employing simultaneously the comparison between the mark and the print of the case, the within-variability of the suspects' finger and the between-variability of the mark with respect to a database, can then be based on representative data. Thus, these data allow an evaluation which may be more detailed than that obtained by the application of rules established long before the advent of these large databases or by the specialists experience. The goal of the present thesis is to evaluate likelihood ratios, computed based on the scores of an automated fingerprint identification system when the source of the tested and compared marks is known. These ratios must support the hypothesis which it is known to be true. Moreover, they should support this hypothesis more and more strongly with the addition of information in the form of additional minutiae. For the modeling of within- and between-variability, the necessary data were defined, and acquired for one finger of a first donor, and two fingers of a second donor. The database used for between-variability includes approximately 600000 inked prints. The minimal number of observations necessary for a robust estimation was determined for the two distributions used. Factors which influence these distributions were also analyzed: the number of minutiae included in the configuration and the configuration as such for both distributions, as well as the finger number and the general pattern for between-variability, and the orientation of the minutiae for within-variability. In the present study, the only factor for which no influence has been shown is the orientation of minutiae The results show that the likelihood ratios resulting from the use of the scores of an AFIS can be used for evaluation. Relatively low rates of likelihood ratios supporting the hypothesis known to be false have been obtained. The maximum rate of likelihood ratios supporting the hypothesis that the two impressions were left by the same finger when the impressions came from different fingers obtained is of 5.2 %, for a configuration of 6 minutiae. When a 7th then an 8th minutia are added, this rate lowers to 3.2 %, then to 0.8 %. In parallel, for these same configurations, the likelihood ratios obtained are on average of the order of 100,1000, and 10000 for 6,7 and 8 minutiae when the two impressions come from the same finger. These likelihood ratios can therefore be an important aid for decision making. Both positive evolutions linked to the addition of minutiae (a drop in the rates of likelihood ratios which can lead to an erroneous decision and an increase in the value of the likelihood ratio) were observed in a systematic way within the framework of the study. Approximations based on 3 scores for within-variability and on 10 scores for between-variability were found, and showed satisfactory results. Résumé : Dans le domaine des empreintes digitales, l'essor des outils informatisés a permis de créer de puissants algorithmes de recherche automatique. Ces algorithmes permettent, entre autres, de comparer une trace à une banque de données d'empreintes digitales de source connue. Ainsi, le lien entre la trace et l'une de ces sources peut être établi. Avec la croissance des capacités de ces systèmes, des potentiels de stockage de données, ainsi qu'avec une collaboration accrue au niveau international entre les services de police, la taille des banques de données augmente. Le défi actuel pour le domaine de l'identification par empreintes digitales consiste en la croissance de ces banques de données, qui peut permettre de trouver des impressions très similaires mais provenant de doigts distincts. Toutefois et simultanément, ces données et ces systèmes permettent une description des variabilités entre différentes appositions d'un même doigt, et entre les appositions de différents doigts, basées sur des larges quantités de données. Cette description statistique de l'intra- et de l'intervariabilité calculée à partir des minuties et de leurs positions relatives va s'insérer dans une approche d'interprétation probabiliste. Le calcul d'un rapport de vraisemblance, qui fait intervenir simultanément la comparaison entre la trace et l'empreinte du cas, ainsi que l'intravariabilité du doigt du suspect et l'intervariabilité de la trace par rapport à une banque de données, peut alors se baser sur des jeux de données représentatifs. Ainsi, ces données permettent d'aboutir à une évaluation beaucoup plus fine que celle obtenue par l'application de règles établies bien avant l'avènement de ces grandes banques ou par la seule expérience du spécialiste. L'objectif de la présente thèse est d'évaluer des rapports de vraisemblance calcul és à partir des scores d'un système automatique lorsqu'on connaît la source des traces testées et comparées. Ces rapports doivent soutenir l'hypothèse dont il est connu qu'elle est vraie. De plus, ils devraient soutenir de plus en plus fortement cette hypothèse avec l'ajout d'information sous la forme de minuties additionnelles. Pour la modélisation de l'intra- et l'intervariabilité, les données nécessaires ont été définies, et acquises pour un doigt d'un premier donneur, et deux doigts d'un second donneur. La banque de données utilisée pour l'intervariabilité inclut environ 600000 empreintes encrées. Le nombre minimal d'observations nécessaire pour une estimation robuste a été déterminé pour les deux distributions utilisées. Des facteurs qui influencent ces distributions ont, par la suite, été analysés: le nombre de minuties inclus dans la configuration et la configuration en tant que telle pour les deux distributions, ainsi que le numéro du doigt et le dessin général pour l'intervariabilité, et la orientation des minuties pour l'intravariabilité. Parmi tous ces facteurs, l'orientation des minuties est le seul dont une influence n'a pas été démontrée dans la présente étude. Les résultats montrent que les rapports de vraisemblance issus de l'utilisation des scores de l'AFIS peuvent être utilisés à des fins évaluatifs. Des taux de rapports de vraisemblance relativement bas soutiennent l'hypothèse que l'on sait fausse. Le taux maximal de rapports de vraisemblance soutenant l'hypothèse que les deux impressions aient été laissées par le même doigt alors qu'en réalité les impressions viennent de doigts différents obtenu est de 5.2%, pour une configuration de 6 minuties. Lorsqu'une 7ème puis une 8ème minutie sont ajoutées, ce taux baisse d'abord à 3.2%, puis à 0.8%. Parallèlement, pour ces mêmes configurations, les rapports de vraisemblance sont en moyenne de l'ordre de 100, 1000, et 10000 pour 6, 7 et 8 minuties lorsque les deux impressions proviennent du même doigt. Ces rapports de vraisemblance peuvent donc apporter un soutien important à la prise de décision. Les deux évolutions positives liées à l'ajout de minuties (baisse des taux qui peuvent amener à une décision erronée et augmentation de la valeur du rapport de vraisemblance) ont été observées de façon systématique dans le cadre de l'étude. Des approximations basées sur 3 scores pour l'intravariabilité et sur 10 scores pour l'intervariabilité ont été trouvées, et ont montré des résultats satisfaisants.

Detection of Mycobacterium leprae DNA by polymerase chain reaction in the blood of individuals, eight years after completion of anti-leprosy therapy

Thirty eight patients with indeterminate leprosy (HI), at least 4 to 6 years after discharge from multibacillary (MB) or paucibacillary (PB) schemes of anti leprosy multidrug therapy (MDT), were submitted to traditional diagnostic procedures for leprosy and to polymerase chain reaction (PCR) analysis of different clinical samples for detection of Mycobacterium leprae DNA. No significant difference was observed for any of the parameters analyzed between PB or MB schemes of treatment and no indications were found for more efficient outcome of HI using the MB scheme. Remarkably, 18 (54.5%) of the individuals were PCR positive in at least one of the samples: positivity of PCR was highest in blood samples and four individuals were PCR positive in blood and some other sample. Upon comparison of PCR results with clinical and histopathological parameters, no correlation was found between PCR-positivity and eventual relapse. This is the first report on detection of M. leprae DNA in PB patients, more than half a decade after completion of MDT, suggesting that live bacilli are present and circulating much longer than expected, although reinfection of the individuals can not be excluded. Overall, we feel that because of the high sensitivity of the assay, extreme care should be taken about association of PCR results, efficacy of treatment and disease status.

Detection of Hepatitis B Virus Antigens in Paraffin-embedded Liver Specimens from the Amazon Region, Brazil

Hepatic viscerotomy of paraffin-preserved old specimens, collected in the period from 1934 to 1967, were analyzed by immunohistochemical assays to detect hepatitis B, hepatitis D, dengue and yellow fever virus antigens. The material belongs to the Yellow Fever Collection, Department of Pathology, Instituto Oswaldo Cruz, Rio de Janeiro, Brazil and the cases were diagnosed at that time according to clinical aspects and histopathological findings reporting viral hepatitis, yellow fever, focal necrosis and hepatic atrophy. From the 79 specimens, 69 were collected at the Labrea Region and the other 10 in different other localities in the Amazon Region. The five micra thick histological slices were analyzed for the presence of hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) by immunoperoxidase technique. An immunofluorescence assay was applied to the detection of hepatitis D, yellow fever and dengue virus antigens. Nine (11.4%) histological samples were HBsAg reactive and 5 (6.3%) were HBcAg reactive. The oldest reactive sample was from 1934. Viral antigens related to the other pathologies were not detected in this study. Our results confirm that the methodology described may be used to elucidate the aetiology of hepatitis diseases even after a long time of conservation of the specimens.

A Heminested Polymerase Chain Reaction for the Detection of Brazilian Rabies Isolates from Vampire Bats and Herbivores

A heminested-PCR (hn-PCR) using primers to the nucleoprotein-coding gene in a nested set was evaluated in the detection of Brazilian strains of rabies virus (RV). A representative number of RV nucleoprotein sequences belonging to genotype 1 were aligned. Based on such alignment, primers were directed to highly conserved regions. All 42 clinical samples positive by both fluorescent antibody and mouse inoculation tests were also positive by the hn-PCR. Brain tissue that had been left to decompose, obtained from an experimentally inoculated mouse was tested by hn-PCR and yielded positive results. In conclusion, primers designed here were capable of amplifying Brazilian RV isolates obtained from a rural epidemiological cycle.

Detection and Characterization of Rotavirus G and P Types from Children Participating in a Rotavirus Vaccine Trial in Belém, Brazil

This study sought the characterization of rotaviruses in a trial with a tetravalent rhesus-human rotavirus vaccine in Belém, Brazil in children who received three doses of vaccine or placebo in the 1st, 3rd and 5th months of life. Rotavirus electropherotypes, subgroups, G serotypes, G, [P] and [P],G genotypes were determined in 93.3%, 95.9%, 93.3%, 73.3%, 95.5% and 92.2% of isolates, respectively. Serotypes G1, G2 and G4 were detected in 58.9%, 30% and 4.4% of the cases, respectively. Rotavirus genotype G5 was detected for the first time in Northern region in 4.4% of the infections. Rotavirus genotypes P[8], P[4], P[6] and P[8+6] were detected in 54.5%, 26.7%, 12.2%, and 2.2% of the cases, respectively. The predominant genotypes were P[8],G1 and P[4],G2 with 53% and 26.6% of the infections, respectively. Unusual strains accounted for 20.5% including P[4],G1, P[6],G1, P[6],G4, P[6],G5, P[8],G2, P[8],G5. Mixed infections involving P[8+6],G2 and P[8+6],G1 were also noted. The neonatal P[6] strains associated with diarrhea were detected among children aged 9-24 months. To our knowledge, this study represents the first in Brazil to analyse, on molecular basis, rotavirus genotypes from children participating in a rotavirus vaccine trial. These results are of potential importance regarding future rotavirus vaccination strategies in Brazil.

Comparison between the Counter Immunoelectrophoresis Test and Mouse Neutralization Test for the Detection of Antibodies against Rabies Virus in Dog Sera

The detection of rabies antibodies is extremely valuable for epidemiological studies, determination of immune status in man, animals, and for the diagnosis of the disease. Several serological procedures have been described for this purpose. The present study reports a comparison between counterimmunoelectrophoresis test (CIET) and mouse neutralization test (MNT) in the detection of antibodies against rabies virus from 212 serum samples of vaccinated dogs. The agreement between both techniques was 79.7% and a significative association was demonstrated. The correlation coefficients between MNT and the CIET titers was determined considering 88 samples showing positive results in both techniques [CIET = 2 and MNT = 5 (0.13 IU/ml)] and resulted r² = 0.7926 (p < 0.001). The performance of CIET system was technically simple, cheap and rapid, and thereby it could be useful for serological monitoring of dog vaccination campaigns as well as for individual analysis.

Evaluation of aggregating brain cell cultures for the detection of acute organ-specific toxicity.

As part of the ACuteTox project aimed at the development of non-animal testing strategies for predicting human acute oral toxicity, aggregating brain cell cultures (AGGR) were examined for their capability to detect organ-specific toxicity. Previous multicenter evaluations of in vitro cytotoxicity showed that some 20% of the tested chemicals exhibited significantly lower in vitro toxicity as expected from in vivo toxicity data. This was supposed to be due to toxicity at supracellular (organ or system) levels. To examine the capability of AGGR to alert for potential organ-specific toxicants, concentration-response studies were carried out in AGGR for 86 chemicals, taking as endpoints the mRNA expression levels of four selected genes. The lowest observed effect concentration (LOEC) determined for each chemical was compared with the IC20 reported for the 3T3/NRU cytotoxicity assay. A LOEC lower than IC20 by at least a factor of 5 was taken to alert for organ-specific toxicity. The results showed that the frequency of alerts increased with the level of toxicity observed in AGGR. Among the chemicals identified as alert were many compounds known for their organ-specific toxicity. These findings suggest that AGGR are suitable for the detection of organ-specific toxicity and that they could, in conjunction with the 3T3/NRU cytotoxicity assay, improve the predictive capacity of in vitro toxicity testing.

A new automated method versus continuous positive airway pressure method for measuring pressure-volume curves in patients with acute lung injury

Objective: To compare pressure–volume (P–V) curves obtained with the Galileo ventilator with those obtained with the CPAP method in patients with ALI or ARDS receiving mechanical ventilation. P–V curves were fitted to a sigmoidal equation with a mean R2 of 0.994 ± 0.003. Lower (LIP) and upper inflection (UIP), and deflation maximum curvature (PMC) points calculated from the fitted variables showed a good correlation between methods with high intraclass correlation coefficients. Bias and limits of agreement for LIP, UIP and PMC obtained with the two methods in the same patient were clinically acceptable.

Incidenceof out-of-hospital adult nontraumatic cardiac arrest presenting as a convulsion

Introduction: The majority of convulsions are due to an epileptic seizure or a convulsive syncope. The incidence of out-of-hospital cardiac arrest (OH-CA) presenting as a convulsion is unknown. Objective: This study aimed to measure the incidence of adult nontraumatic OH-CA presenting as a convulsion, a rate that has not been published so far, to the best of our knowledge. Methods: We prospectively collected all incoming calls with an out-of-hospital nontraumatic seizure as the chief complaint in patients >18 years old during a 24-month period. Among these calls, we collected cases identified as OH-CA by paramedics. Results: During the 24-month period, the emergency medical services (EMS) dispatch center received 561 calls for an out-of-hospital nontraumatic convulsion in an adult. Twelve cases were ultimately classified as CA. In this group, one bystander spontaneously reported that the patient was known for epilepsy. The incidence of OH-CA presenting as convulsions was therefore 2.1% of all calls for convulsion. Over the same period, the EMS dispatch center received 1,035 calls related to an adult nontraumatic OH-CA. Therefore, the rate of OH-CA presenting as a convulsion represented 1.2% of all adult nontraumatic OH-CA. Conclusion:L Only 12 cases out of the 531 calls for nontraumatic adult convulsions were confirmed OHCA (2.1%). Nevertheless, this unusual presentation of OH-CA must be recognized by dispatchers, even when a patient is reported by bystander as a known epileptic. Dispatchers should keep bystanders on the line or call them back before paramedics' arrival, and have them confirm the progressive return of a normal pat- tern of breathing and state of consciousness; if not, they should encourage the bystander to initiate CPR when necessary. An intervention should be implemented to improve the detection by dispatchers of OH-CA presenting as convulsion by the development of a specific interview and directed observation. For dispatchers, a past medical history of epilepsy should not be regarded as sufficient information to rule out OH-CA. It is mandatory that known epileptic patients should be monitored in the same way as nonepileptic patients.