Clinical application of differential time to positivity of blood cultures as a diagnostic method for catheter-related bloodstream infection.

La sospita de bacterièmia relacionada a catèter (BRC) necessita la retirada d’aquest, confirmant-se a posteriori només en un 15-25%. La diferencia en el temps de positivització d´ hemocultius (DTP) ha demostrat ser un mètode fiable per el diagnòstic de BRC evitant la retirada del catèter. Amb la intenció de comprovar la utilitat clínica de la DTP, l’hem comparada amb un mètode diagnòstic estàndard. Hem inclòs 133 pacients ingressats a una unitat de cures intensives portadors de catèters venosos centrals. 56 pacients s’han aleatoritzats. No hem trobat diferències significatives en quant a morbi-mortalitat en els 2 grups havent evitat 70% de retirada innecessària de catèters en el grup de DTP.

Palm-plantar pallor as a diagnostic method of mild-moderate anemia

Objective: to determine the palm-plant paleness’ characteristics in Colombian infant rural population, as a diagnostic method of anemia, and to establish a correlation between the finding of palm-plant paleness and the Hematocrit values. Methodology: a cross sectional study was used to evaluate 169 boys and girls, between 2 months and 12 years old, of the rural area of San Vicente del Caguan, who entered into a Health Campaign. Following the signature of an informed consent, parents accept their children to participate in the study. Those with acute or chronic pathologies were excluded. The presence of palm-plant paleness was determined by observers trained in the Integrated Management of Childhood Illness (IMCI) Strategy. Hematocrit was measured to all children, as well as a peripheral blood smear. Interrater concordance evaluation (Kappa index) was determined through a pilot test and a validation (sensitivity, specificity) was performed, using Hematocrit as the standard. Results: 93 of the participants were male and 77 were female. 45% of them had palm paleness. The Hematocrit showed anemia in 34.1% of the children. The validation analysis demonstrated a 67.2% of sensibility, a 66.6% of specificity, a 51.3% of positive predictive values and a 79.5% of negative predictive values. Hypochromic and Eosinophilia were found in most of the peripheral blood smears’ children with anemia. Conclusions: although this tool presents a low sensibility and specificity for low/moderated anemia, it is useful for excluding it in infants without palm paleness.

ARFI elastography as a complementary diagnostic method for mammary neoplasia in female dogs - preliminary results

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Fluorescence energy transfer detection as a homogeneous DNA diagnostic method

A homogeneous DNA diagnostic assay based on template-directed primer extension detected by fluorescence resonance energy transfer, named template-directed dye-terminator incorporation (TDI) assay, has been developed for mutation detection and high throughput genome analysis. Here, we report the successful application of the TDI assay to detect mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, the human leukocyte antigen H (HLA-H) gene, and the receptor tyrosin kinase (RET) protooncogene that are associated with cystic fibrosis, hemochromatosis, and multiple endocrine neoplasia, type 2, respectively. Starting with total human DNA, the samples are amplified by the PCR followed by enzymatic degradation of excess primers and deoxyribonucleoside triphosphates before the primer extension reaction is performed. All these standardized steps are performed in the same tube, and the fluorescence changes are monitored in real time, making it a useful clinical DNA diagnostic method.

PKO: alternative method for isolating mycobacteria from sputum

We elaborated an alternative culture method, which we denominated PKO (initials in tribute of respect to Petroff, Kudoh and Ogawa), for isolating Mycobacterium tuberculosis from sputum for diagnosis of pulmonary tuberculosis (TB), and to compare its performance with the Swab and Petroff methods. For the technique validation, sputum samples from patients suspected of pulmonary TB cases were examined by acid-fast microscopy (direct and concentrated smear), PKO, Swab and Petroff methods. We found that Petroff and PKO methods have parity in the effectiveness of M. tuberculosis isolation. However, by the PKO method, 65% of isolated strains were detected in a period of £15 days, while by the Petroff method the best detection was in an interval of 16-29 days (71%). In positive smear samples, the average time of PKO isolation is only superior to the one related for Bactec 460TB. In conclusion, the exclusion of the neutralization stage of pH in the PKO reduces the manipulation of the samples, diminishes the execution time of the culture according to the Petroff method and facilitates the qualification of professionals involved in the laboratorial diagnosis of Tuberculosis.

Efficacy of an enzyme-linked immunosorbent assay as a diagnostic tool for schistosomiasis mansoni in individuals with low worm burden

IgM-ELISA is an immunoenzymatic method useful for detection of IgM antibodies against a fraction of Schistosoma mansoni adult worm antigen (AWA) that is soluble in trichloroacetic acid (AWA-TCA). This method was applied to three groups of individuals with different clinical and epidemiological characteristics, and the results compared with those obtained by other diagnostic methods: immunofluorescence test for detection of IgM antibodies (IgM-IFT) or IgG antibodies (IgG-IFT), ELISA for detection of IgG antibodies (IgG-ELISA), and two parasitological methods, Kato-Katz and miracidium hatching. The IgM-ELISA presented a sensitivity of 98%, when the parasitologic fecal examination was defined as reference diagnostic method, and a specificity of 98 and 97.3%, respectively for the group of clinically healthy individuals and other helminth carriers. A comparative analysis between the results of IgM-ELISA and those obtained by other serologic tests showed a good degree of agreement, with Kappa indices ranging from 0.95 to 0.98. The diagnostic efficacy of 97.8%, as determined with schistosomiasis patients with low parasitic burden, suggests the excellent performance of the IgM-ELISA and its usefulness for the diagnosis of schistosomiasis when applied in low endemic areas.

The diagnostic dilemma of hyperintense fetal lung on prenatal MRI : 12.03

Purpose: In the last years, MRI appears as a complementary diagnostic method to US in the diagnosis of congenital lung lesions. Focal homogeneous pulmonary hyperintensity on T2-WI constitutes a frequent pattern observed. Our purpose is to determine if this finding is associated with a characteristic pulmonary lesion. Materials and methods: Between 01.01.00 and 31.12.07, a total of 50 prenatal MRI in fetuses with echographic diagnosis of thoracic pathology were performed in our institution, including 12 cases of suspected congenital pulmonary lesions. Prenatal images were correlated with post-natal diagnosis. Results: In 12 cases, fetal MRI detected congenital pulmonary lesions. In 8 patients, typical signs (cystic lesions, septations, anomalous vasculature) clearly suggested a specific pathology. In 4 cases, MRI showed a focal homogeneous increase of the signal intensity (SI) on T2-WI of the pathologic lung related to the normal one. The final diagnosis of these fetuses included 1 patient with congenital cystic adenomatoid malformation type III, 1 patient with segmental emphysema and 2 cases of bronchial atresia. In all 4 cases, a significant post-natal reduction of the lesion size related to prenatal MRI studies was observed. Conclusion: Our study suggests that a focal increment of the SI of the lung on T2-WI is a non specific sign of congenital lung disease, present in different pathologies. Therefore, a prospective diagnosis is not possible.

Facteurs de risque d´introduction et diagnostic de Mycobacterium avium ssp. paratuberculosis

Mycobacterium avium ssp. paratuberculosis (MAP) est l'agent causal de la paratuberculose, maladie entérique, chronique et incurable des ruminants, avec un impact économique important. Une meilleure compréhension des facteurs de risque associés à l'introduction de la maladie dans un troupeau est essentielle pour sa prévention. L’amélioration des tests diagnostiques est aussi importante pour son contrôle. L’introduction des nouveaux animaux dans le troupeau et la présence et contact des différentes espèces sauvages et domestiques avec les vaches, semblent être des facteurs de risques d’introduction de la maladie. Nous avons réalisé une revue systématique dont l`objective était de recueillir l’information pertinente pour répondre à la question sur l’importance de ces facteurs et leur impact sur l’introduction de la maladie dans un troupeau. D`un autre côté, la détection de MAP dans les fèces par culture bactérienne demeure la méthode diagnostique de choix malgré les facteurs qui l`affectent. Une série de 3 étapes est requise afin de confirmer la présence du MAP : (1) culture (2) coloration, et (3) confirmation du MAP par PCR (si détecté à l´étape 2). Certains échantillons fécaux présentent une particularité en raison de leur forte charge de micro-organismes. Ces contaminants peuvent interférer avec la croissance et la détection de MAP. Une étude visant à : a) estimer l'impact des certain covariables sur les résultats de la culture de MAP parmi l`analyse rétrospective d`un banque des données et b) évaluer la possibilité d'optimiser le processus de diagnostic du MAP en effectuant l'analyse PCR sur les cultures déclarées comme contaminées a été réalisée.

Diagnostic of Silicon Carbide Surge Arresters using Leakage Current Measurement

Nowadays, the zinc oxide surge arresters (ZnO) are widely used in power systems, however, a large number of silicon carbide surge arresters (SiC) are still in service in the utilities. On the other hand, it is not possible to replace all SiC surge arresters in a short time period, being necessary to review the maintenance program taking into account the surge arresters that are more degraded. In this context, a research project was established between the University of Sao Paulo and the electrical utility CTEEP, aiming the investigation of its SiC surge arresters. This work shows that the leakage current measurement, a diagnostic method for the ZnO surge arresters, can provide useful information related to the condition of the SiC surge arresters. Analysis of the amplitude and distortion of the leakage current, also considering thermovision measurements, resulted in better evaluation of the SiC surge arresters.

Diagnostic utility of thyroglobulin measurement in the fine needle aspirates from cervical lymph nodes: a case report

Fine needle aspiration cytology (FNAC) is the more accurate diagnostic method for cervical lymph node (CLN) metastasis from differentiated thyroid cancers (DTC). However, FNAC diagnosis of cystic CLN is, in most cases, uninformative due to inadequate cellularity. Recently, thyroglobulin (Tg) detection in FNAC needle washout fluid has been shown to improve the diagnostic accuracy of FNAC, and its routine association with cytology is recommended. We here describe the case of a 20 yr old girl complaining of the recent appearance of palpable non-painful laterocervical nodes in the neck. Ultrasound examination revealed the presence of 3 cystic CLNs and 2 mixed thyroid nodules, with the larger one showing irregular margins. On the latter, and on 2 larger CLNs, FNAC was performed, and both Tg protein and mRNA were determined in the needle washout. The cytological analysis was not diagnostic for the two CLNs, while that of the thyroid nodule reported the presence of colloid and groups of thyrocytes with normal morphology. Both CLNs showed, however, high levels of Tg protein and were positive for Tg mRNA, suggestive of metastatic DTC. Based on these findings, the FNAC analysis was performed on the second smaller thyroid nodule suggesting (Tir4) the presence of PTC. The patient was then subjected to total thyroidectomy with lymph nodes resection of the central and homolateral compartments. The histological diagnosis confirmed the presence of a PTC in the small nodule and metastatic lymph nodes. In conclusion, this case confirms that the cytological diagnosis of cystic lymph nodes is challenging, and that the measurement of Tg protein and/or mRNA in the needle washout may overcome this limitation.

Padronização do eletrorretinograma de campo total em cães

Eletrorretinograma (ERG) é o meio diagnóstico objetivo e não-invasivo para avaliar a função retiniana e detectar precocemente, em várias espécies, lesões nas suas camadas mais externas. As indicações mais comuns para ERG em cães são: avaliação pré-cirúrgica de pacientes com catarata, caracterização de distúrbios que causam cegueira, além de servir como importante modelo para o estudo da distrofia retiniana que acomete o homem. Vários são os fatores que podem alterar o ERG tais como: eletrorretinógrafo, fonte de estimulação luminosa, tipo do eletrodo, tempo de adaptação ao escuro, tamanho pupilar, opacidade de meios e protocolo de sedação ou anestesia; além da espécie, raça e idade. Objetivou-se com este estudo padronizar o ERG para cães submetidos à sedação, seguindo o protocolo da International Society for Clinical Electrophysiology of Vision (ISCEV), utilizando Ganzfeld e eletrodos Burian Allen. Foram realizados 233 eletrorretinogramas em cães, 147 fêmeas e 86 machos, com idades entre um e 14 anos. Dos 233 cães examinados, 100 apresentavam catarata em diferentes estágios de maturação, 72 eram diabéticos e apresentavam catarata madura ou hipermadura, 26 apresentaram eletrorretinograma compatível com degeneração retiniana progressiva, três apresentaram eletrorretinograma compatível com síndrome da degeneração retiniana adquirida subitamente e 32 não apresentaram lesão retiniana capaz de atenuar as respostas do ERG, sendo considerados normais quanto à função retiniana. A sedação foi capaz de produzir boa imobilização do paciente sem rotacionar o bulbo ocular, permitindo adequada estimulação retiniana bilateralmente, com auxílio do Ganzfeld. O sistema eletrodiagnóstico Veris registrou com sucesso e simultaneamente de ambos os olhos, as cinco respostas preconizadas pela ISCEV. Como o ERG de campo total tornou-se exame fundamental na rotina oftalmológica, sua padronização é indispensável quando se objetiva comparar resultados de laboratórios distintos. A confiabilidade e reprodutibilidade deste protocolo foi demonstrada com a obtenção de registros de ótima qualidade utilizando protocolo padrão da ISCEV, eletrorretinógrafo Veris, Ganzfeld e eletrodos Burian Allen nos cães submetidos à sedação.

Fluorescence images combined to statistic test for fingerprinting of citrus plants after bacterial infection

The citrus greening (or huanglongbing) disease has caused serious problems in citrus crops around the world. An early diagnostic method to detect this malady is needed due to the rapid dissemination of Candidatus Liberibacter asiaticus (CLas) in the field. This analytical study investigated the fluorescence responses of leaves from healthy citrus plants and those inoculated with CLas by images from a stereomicroscope and also evaluated their potential for the early diagnosis of the infection caused by this bacterium. The plants were measured monthly, and the evolution of the bacteria on inoculated plants was monitored by real-time quantitative polymerase chain reaction (RT-qPCR) amplification of CLas sequences. A statistical method was used to analyse the data. The selection of variables from histograms of colours (colourgrams) of the images was optimized using a paired Student's t-test. The intensity of counts for green colours from images of fluorescence had clearly minor variations for healthy plants than diseased ones. The darker green colours were the indicators of healthy plants and the light colours for the diseased. The method of fluorescence images is novel for fingerprinting healthy and diseased plants and provides an alternative to the current method represented by PCR and visual inspection. A new, non-subjective pattern of analysis and a non-destructive method has been introduced that can minimize the time and costs of analyses.

CR3 (CD11b/CD18) activation of nasal neutrophils: a measure of upper airway endotoxin exposure

Inhaled endotoxin (lipopolysaccharide, LPS) initiates an inflammatory response and leads to the expression of CR3 (CD11b/CD18) receptors on polymorphonuclear leukocytes (PMNs). We determined if PMN activation in nasal lavage fluid (NLF) is a possible biomarker of occupational endotoxin exposure. Seven subjects exposed to endotoxin provided NLF samples that were split into three aliquots (negative control - 1 M nicotinamide; sham; positive control - 11 eta g of exogenous LPS) and PMN activation was measured using a chemiluminometer. Differences in mean PMN activation were apparent, negative control: 548 +/- 15.65 RLU 100 mu l(-1); sham: 11469 +/- 2582 RLU 100 mu l(-1); positive control: 42026 +/- 16659 RLU 100 mu l (n = 7; p < 0.05). This technique shows promise as a diagnostic method for measuring upper airway LPS exposure.