Methodological aspects of Universal immuno-PCR on standard tubes.

One of the most used formats in inmuno-polymerase chain reaction (IPCR) is known as "Universal" IPCR (signal-generating complexes is based on conjugates of biotinylated DNA, biotinylated IgG and avidin). In the present study, we evaluated the utility of using mono- and bi-biotinylated DNA probes, pre-self-assembled DNA-neutravidin complex, blocking step and glutaraldehyde pretreatment of standard PCR tubes to improve the analytical performance of the hTSH-IPCR assay. The use of pre-self-assembled mono-biotinylated DNA-neutravidin complex enhances both the sensitivity and the reproducibility of the hTSH-IPCR assay, even without blocking step: hTSH-IPCR assay showed an improved limit of detection (LOD: 0.01 µIU/ml), calibration sensitivity (SEN: 2.4) and analytic sensitivity (γ: 9 µIU/ml-1) in comparison with both a self-made ELISA and a commercial one.

The UV filter benzophenone 3, alters early follicular assembly in rat whole ovary cultures.

Our goal was to study the effect of BP3 (benzophenone 3) in the follicular assembly and the potential involvement of Foxl2 pathway using whole ovary cultures. Ovaries were collected from Wistar rats at birth, treated in vitro with vehicle (0.01% DMSO), BP3 (5.8 nM, 276 nM, 576 nM and 876 nM) or ESR2 inhibitor (0.1 nM), and cultured for 7 days. Nest breakdown, follicular assembly and the expression of several regulators of these processes (p27, Foxl2, Sox9, Bmp2, Cyp19 and Fst) were evaluated. In vitro exposure to BP3 (5.8 nM) decreased the population of total oocytes, the number of nests per ovary and early primary follicles population. In addition, BP3 (5.8 nM) induced overexpression of Foxl2 mRNA levels through ESR2 but increased Fst mRNA levels independently from ESR2 or Foxl2. We also observed that the number of p27-positive oocytes was decreased after BP3 (5.8 nM). On the other hand, exposure to BP3-276 increased total oocytes, the number of nests per ovary and decreased primary follicles. In addition, BP3-276 induced no changes of Foxl2 mRNA levels through ESR2 but increased Fst mRNA levels independently from ESR2 or Foxl2. In conclusion, our study clearly shows that exposure to BP3 is to perturb the early events of germ cell development as showed here in whole ovary cultures.

Development of a quantitative immuno-polymerase chain reaction assay to detect and quantify low levels of human thyroid stimulating hormone.

In the present study, we developed both a conventional enzyme-linked immunosorbent assay (ELISA) and a highly sensitive immuno-polymerase chain reaction (IPCR) assay specific for detection of human thyroid stimulating hormone (hTSH). Several anti-hTSH monoclonal antibodies (MAbs) were generated using hybridoma technology. Two pairs of MAbs (B-4 and B-9) were rationally selected and the optimal assay conditions of sandwich ELISAs were established. The ELISA prototypes were evaluated with standards calibrated with WHO 2nd International Reference Preparation for hTSH and in comparison with a commercial ELISA Kit. Although the limit of detection (LOD) was 0.1 µIU/ml in all cases, B-9-ELISA showed an analytical performance similar to commercial ELISA Kit. Therefore, we selected the B-9 ELISA to develop a hTSH-IPCR assay applying an "Universal-IPCR" format in standard PCR tubes without pretreatment. The signal amplification was achieved through the interaction between the biotinylated detection MAb and mono-biotinylated DNA probe pre-self-assembled with neutravidin. The hTSH-IPCR assay showed a significant increase in terms of the slope definition of sensitivity in low levels range. Our results support the potential of IPCR technique for being applied in clinical diagnosis of thyroid states.

Impaired ovarian response to exogenous gonadotropins in female rat offspring born to mothers perinatally exposed to Bisphenol A.

The ovary is sensitive to disruption by the environmental estrogen Bisphenol A (BPA). Our aim was to investigate whether perinatal exposure to BPA (50µg/kgday), orally administered, affects ovarian response to exogenous gonadotrophins (PMSG or PMSG+hCG) in prepubertal female offspring. An altered response to gonadotrophins was observed in BPA-exposed rats. Increased proportion of antral follicles, altered levels of ovarian steroidogenic enzymes, gonadotropin receptors, AR and ERß were observed in PMSG group. Besides that, in response to PMSG+hCG, a persistent high Fshr mRNA expression and a decreased number of follicles with high expression of PR before ovulation were observed. After ovulation, there was an increase in antral atretic follicles, reduced Lhcgr mRNA expression and high serum levels of E2. Therefore, an early exposure to a low dose of BPA during perinatal period induces ovarian changes leading to an altered response to exogenous gonadotropin treatment later in life.

Production of monoclonal antibodies and development of a quantitative immuno-polymerase chain reaction assay to detect and quantify recombinant Glutathione S-transferase.

GST-tagged proteins are important tools for the production of recombinant proteins. Removal of GST tag from its fusion protein, frequently by harsh chemical treatments or proteolytic methods, is often required. Thus, the monitoring of the proteins in tag-free form requires a significant effort to determine the remnants of GST during purification process. In the present study, we developed both a conventional enzyme-linked immunosorbent assay (ELISA) and an immuno-polymerase chain reaction (IPCR) assay, both specific for detection of recombinant GST (rGST). rGST was expressed in Escherichia coli JM109, using a pGEX4T-3 vector, and several anti-rGST monoclonal antibodies were generated using hybridoma technology. Two of these were rationally selected as capture and detection antibodies, allowing the development of a sandwich ELISA with a limit of detection (LOD) of 0.01 µg/ml. To develop the rGST-IPCR assay, we selected "Universal-IPCR" format, comprising the biotin-avidin binding as the coupling system. In addition, the rGST-IPCR was developed in standard PCR tubes, and the surface adsorption of antibodies on PCR tubes, the optimal neutravidin concentrations, the generation of a reporter DNA and the concentration effect were studied and determined. Under optimized assay conditions, the rGST-IPCR assay provided a 100-fold increase in the LOD as well as an expanded working range, in comparison with rGST-ELISA. The proposed method exhibited great potentiality for application in several fields in which measurement of very low levels of GST is necessary, and might provide a model for other IPCR assays.

[Cardiac attacks in patients with acute Chagas disease in a family micro-outbreak, in Abaetetuba, Brazilian Amazon]. / Acometimento cardíaco em pacientes com doença de Chagas aguda em microepidemia familiar, em Abaetetuba, na Amazônia Brasileira.

The authors describe the main clinical findings relative to cardiac involvement, in patients with acute Chagas' disease (CD) in yet another familial micro-epidemic episode of CD in Amazon region. Thirteen patients were studied with acute Chagas' disease, resident in the city of Abaetetuba in Pará state; they were submitted to clinical and heart evaluation, with electrocardiograph and echocardiograph exams. Ventricular extrasystole occurred in 38.5% of the cases. Right bundle branch block and 1st and 2nd degree atrioventricular block were found in 30.8% of the patients. Attention is called to two findings in the Doppler echocardiography: pericardiac involvement and an image suggestive of aneurismatic formation in two patients. The findings reveal acute heart disease, with evidence of cardiomyopathy and alterations in the conduction system of the heart, bearing similarity with the description of the disease in endemic areas.