An ultrasensitive Cystatin C renal failure immunosensor based on a PPy/CNT electrochemical capacitor grafted on interdigitated electrode.

An interdigitated immunosensor for Cystatin C detection based on polypyrrole/carbon nanotube electrochemical capacitor is described. Cystatin C (CysC) is powerful biomarker for early acute renal failure and one predictive for cardiovascular risk, sepsis, cancer and death. Recently, electrochemical immunosensors based on interdigitated electrodes (IDE) have been successfully focused on development of point-of-care testing, due to their miniaturization facilities and higher sensitivity as compared with the screen-printed electrochemical sensing. Herein, a polypyrrole/carbon nanotube nanoyhibrid film was grafted on two gold fingers by electropolymerization obtaining a supercapacitor. Anti-CysC antibodies were immobilized on the IDE by covalent entrapment via ethylenediamine bifunctional agent, followed by glycine blocking in acid and alkaline medium. Under low frequency, capacitive effect of antigen-antibody interaction were observed by double layer capacitance, and analytical responses of this IDE immunosensor to CysC serum were obtained by changes on phase angle a linear range up to 300 ng/mL. The cutoff was calculated for serum samples showing a total reducing of non-specific binding at approximately 28 ng/mL CysC. This immunosensor based on interdigitated electrode (IDE) is a potential tools as portable device,with possibility to use as a practical and rapid test for CysC diagnostic in samples of serum.

Evaluation of Virulence Factors In vitro, Resistance to Osmotic Stress and Antifungal Susceptibility of Candida tropicalis Isolated from the Coastal Environment of Northeast Brazil.

Several studies have been developed regarding human health risks associated with the recreational use of beaches contaminated with domestic sewage. These wastes contain various micro-organisms, including Candida tropicalis. In this context, the objective of this study was to characterize C. tropicalis isolates from the sandy beach of Ponta Negra, Natal, Rio Grande do Norte, Brazil, regarding the expression of in vitro virulence factors, adaptation to osmotic stress and susceptibility to antifungal drugs. We analyzed 62 environmental isolates and observed a great variation among them for the various virulence factors evaluated. In general, environmental isolates were more adherent to human buccal epithelial cells (HBEC) than C. tropicalis ATCC13803 reference strain, and they also showed increased biofilm production. Most of the isolates presented wrinkled phenotypes on Spider medium (34 isolates, 54.8%). The majority of the isolates also showed higher proteinase production than control strains, but low phospholipase activity. In addition, 35 isolates (56.4%) had high hemolytic activity (hemolysis index > 0.55). With regard to C. tropicalis resistance to osmotic stress, 85.4% of the isolates were able to grow in a liquid medium containing 15% sodium chloride. The strains were highly resistant to the azoles tested (fluconazole, voriconazole and itraconazole). Fifteen strains were resistant to the three azoles tested (24.2%). Some strains were also resistant to amphotericin B (14 isolates; 22.6%), while all of them were susceptible for the echinocandins tested, except for a single strain of intermediate susceptibility to micafungin. Our results demonstrate that C. tropicalis isolated from the sand can fully express virulence attributes and showed a high persistence capacity on the coastal environment; in addition of showing high minimal inhibitory concentrations to several antifungal drugs used in current clinical practice, demonstrating that environmental isolates may have pathogenic potential.

Noninvasive imaging of the meiotic spindle of in vivo matured oocytes from infertile women with endometriosis.

The objectives of this prospective study were to evaluate the nuclear maturation stage and the presence and location of meiotic spindles of in vivo matured oocytes from infertile women with and without endometriosis (male or tubal causes of infertility) undergoing stimulated cycles for intracytoplasmic sperm injection (ICSI). We also compared the ICSI outcomes among groups. We analyzed the meiotic spindles of oocytes from 36 patients with endometriosis I/II, 24 with endometriosis III/IV, and 60 without endometriosis (male or tubal causes of infertility). The oocytes were imaged using polarization microscopy. There were no differences in the number of oocytes in telophase I (mean [standard deviation]: 0.1 [0.5], 0.2 [0.4], and 0.2 [0.5], respectively, in the endometriosis I/II, endometriosis III/IV, and control groups), in metaphase II with visible spindles (4.2 [2.5], 3.1 [2.0], and 3.6 [2.2], respectively, in the endometriosis I/II, endometriosis III/IV, and control groups), and in spindle location among groups. We can conclude from this study that noninvasive analysis of spindles from in vivo matured oocytes of infertile patients with endometriosis did not demonstrate significant differences in terms of the nuclear maturation stage, the percentage of oocytes in metaphase II with visible spindles, and the spindle localization when compared to the control group. However, it is important to state that there are no studies evaluating the accuracy of polarization microscopy for the detection of meiotic anomalies in human oocytes, which would need to be better evaluated in future studies using an appropriate methodology.

Correlation between TBARS levels and glycolytic enzymes: the importance to the initial evaluation of clinical outcome of colorectal cancer patients.

Colorectal cancer (CRC) has been associated with high levels of lipid peroxidation, probably due to neoplasic tissue metabolism. Our objectives were to relate lipid peroxidation with the evolution of CRC and with various biomarkers (GGT, ALP, LDH, CEA) to assess its prognostic value. A longitudinal study was conducted with CRC patients (n=43), using FOLFOX4. At the end of the treatment, patients were grouped into two groups: poor outcome (PO) for those patients whose computed tomography showed signs of metastasis, not reduced or increased in the previous implants, and not reduced or increased in CEA levels and good outcome (GO) for the opposite trends. PO patients had a significant increase in TBARS levels, being different from other group in cycles 4, 5, and 6 of chemotherapy. After cycle 6 of chemotherapy, GO patients had higher SOD (27%) and catalase (33%) activity. TBARS levels showed a positive correlation with biomarkers at the beginning of the treatment, which disappeared after six cycles of chemotherapy, when TBARS levels of the PO group started to increase; the other parameters increased at a later time. Because the serum TBARS levels in GO patients did not increase after the beginning of chemotherapy, it is expected that the increase is not a result of the effects of chemotherapy but of sickness evolution. It is possible that the systemic assessment of lipid peroxidation might become an additional marker because it occurs earlier than other biomarkers and could therefore be useful in the prognosis of CRC patients.

Enzymes that hydrolyze adenine nucleotides in chronic renal failure: relationship between hemostatic defects and renal failure severity.

The activities of the enzymes NTPDase (E.C.3.6.1.5, apyrase, ATP diphosphohydrolase, ecto-CD 39) and 5'-nucleotidase (E.C.3.1.3.5, CD 73) were analyzed in platelets from patients with chronic renal failure (CRF), both undergoing hemodialysis treatment (HD) and not undergoing hemodialysis (ND), as well as from a control group. The results showed an increase in platelet NTPDase activity in CRF patients on HD treatment (52.88%) with ATP as substrate (P<0.0001). ADP hydrolysis was decreased (33.68% and 39.75%) in HD and ND patients, respectively. In addition, 5'-nucleotidase activity was elevated in the HD (160%) and ND (81.49%) groups when compared to the control (P<0.0001). Significant correlation was found among ATP, ADP and AMP hydrolysis and plasma creatinine and urea levels (P<0.0001). Patients were compared statistically according the time of hemodialysis treatment. We found enhanced NTPDase and 5'-nucleotidase activities between 49 and 72 months on HD patients. Our result suggests the existence of alterations in nucleotide hydrolysis in platelets of CRF patients. Possibly, this altered nucleotide hydrolysis could contribute to hemostasis abnormalities found in CRF.

Vancomycin monitoring in term newborns: comparison of peak and trough serum concentrations determined by high performance liquid chromatography and fluorescence polarization immunoassay

INTRODUCTION: Peak and trough serum concentrations of vancomycin were determined in term newborn infants with confirmed or suspected Staphylococcus sp sepsis by high performance liquid chromatography and flourescence polarization immunoassay. OBJECTIVE: To statistically compare the results of the high performance liquid chromatography and flourescence polarization immunoassay techniques for measuring serum vancomycin concentrations. METHODS: Eighteen peak and 20 trough serum samples were assayed for vancomycin concentrations using high performance liquid chromatography and flourescence polarization immunoassay from October 1995 to October 1997. RESULTS: The linear correlation coefficients for high performance liquid chromatography and flourescence polarization immunoassay were 0.27 (peak, P = 0.110) and 0.26 (trough, P = 0.1045) respectively, which were not statistically significant. CONCLUSION: There was wide variation in serum vancomycin concentrations determined by high performance liquid chromatography as compared with those determined by flourescence polarization immunoassay. There was no recognizable pattern in the variability; in an apparently random fashion, the high performance liquid chromatography measurement was sometimes substantially higher than the flourescence polarization immunoassay measurement, and at other times it was substantially lower

Brain abscess by citrobacter diversus in infancy: case report

Citrobacter diversus is closely related to brain abscess in newborn infants. We describe a case of brain abscess by this bacteria in a newborn infant and his clinical and cranial computed tomographic evaluation until the fourth month of life and discuss therapeutic management of this patient