Voltammetric behavior of benznidazole at a DNA-electrochemical biosensor

Benznidazole is a drug used commonly as a therapeutic agent against Chagas' disease in Brazil. To clarify the cytotoxic action of benznidazole the electrochemical reduction of benznidazole has been investigated using a DNA-electrochemical biosensor, prepared by modification of a glassy carbon electrode with DNA, and the results compared with reduction at a bare glassy carbon electrode. The dependence of peak potential with pH follows slopes of 59 and 52 mV per pH unit in acid media, respectively, which corresponds to a mechanism involving the same number of electrons and protons. In neutral and alkaline solution no significant dependence of peak potential with pH was found. During the electrochemical reduction of benznidazole the formation of the hydroxylamine derivative occurs, involving a total of four electrons. The potentials for reduction were less negative when using the DNA-modified glassy carbon electrode than at the bare glassy carbon electrode although the mechanism was the same, and at pH 7.51 the peak current was four times higher than that obtained with the bare electrode. The DNA-biosensor enabled pre-concentration of the drug onto the electrode surface and the in situ damage caused to the DNA on the electrode surface by the product of benznidazole reduction could be detected electrochemically. The results are in agreement with the hypothesis that the hydroxylamine derivative is the reactive species responsible for the cytotoxic action of benznidazole.     

Streptococcus suis meningitis

Human infection by Streptococcus suis (S. suis) is a zoonosis, with a known occupational risk and clinical presentation mainly as a purulent meningitis with low mortality and frequent hearing loss and ataxia sequela. Less than 150 human cases have been reported since original one thirty years ago. There is a geographical distribution most patients living in northern Europe and south Asia. S. suis disease in human has been reported in two patients in Spain the last years. We present two patients with S. suis meningitis, both were men with occupation related by pork meet, and good outcome. They come at our hospital in a lapse of one month. Both had neurosensorial hearing loss and walking ataxia. One patient had peripheral facial paralysis and diplopia because of paresia of contralateral sixth nerve, with complete resolution at three months. The rare presentation of S. suis meningitis in our country must not forget us to record the working risk at anamnesis.     

Gastric bezoar

Bezoar consist of the accumulation of different substances in the digestive tract. We present the clinical case of a girl with gastric trichobezoar discovered in a postoperatory follow-up to an appendicectomy. Ultra-sound images and oesophagus-gastric transit are fundamental points in the diagnosis. Endoscopy was useful in confirming the diagnosis and in ruling out associated ulcus, frequent in these patients. Surgical treatment is the choice in big bezoar but laser, prokinetics and enzymatic dissolutions have also been used. Theses patients should undergo psychological control.     

Preoperative testing routines for healthy, asymptomatic patients in the Canary Islands (Spain)

OBJECTIVES: To analyze patterns of routine testing before elective/scheduled surgery in healthy/asymptomatic patients classified as ASA I or II according to the American Society of Anesthesiologists. MATERIAL AND METHOD: A questionnaire on the organization of preoperative testing was completed by anesthesiologists at five public hospitals in the Canary Islands. The questionnaire emphasized the most commonly ordered screening procedures, such as chest X-rays, electrocardiograms, laboratory tests and spirometry. RESULTS: Red cell counts were most frequently requested (for 86% of the patients), followed by platelet counts (80%) and blood chemistry (75%) and coagulation studies (72%). Least requested were urine tests and spirometry. The frequencies of electrocardiogram and chest X-ray requests fell between the two extremes, with patient age and the presence of certain indications seeming to affect whether those tests would be ordered or not. The need for such screening was perceived to increase for patients over 40 years of age. The ordering of preoperative tests varied from hospital to hospital and among anesthesiologists at a single site in spite of established protocols. CONCLUSIONS: Hospitals and individual anesthesiologists differ considerably in how they request preoperative tests. The variations can not be explained solely by differing patient needs given that respondents were contemplating only healthy/asymptomatic individuals undergoing relatively simple procedures.     

Intracellular factor XIII crosslinks platelet cytoskeletal elements upon platelet activation

The platelet cytoplasm contains approximately half of the factor XIII (FXIII) transglutaminase content circulating in blood, yet the function of cytoplasmic FXIII is poorly understood. This study investigated functions of platelet FXIII in internal platelet processes by studying the interactions of FXIII with platelet cytoskeletal proteins. FXIII was present in cytoskeletal fractions of platelet lysate separated by centrifugation. When cytoskeletal fractions were immobilized on nitrocellulose membranes, thrombin-activated rFXIII (rFXIIIa*) or calcium ion-treated rFXIII (rFXIIIa degree) bound to some of these proteins, whereas untreated rFXIII did not. Utilizing fluorescence microscopy, an actin polymerization-dependent transient translocation of FXIII from a diffuse homogeneous distribution throughout the cytoplasm to the platelet periphery was observed upon platelet activation, suggesting an association with cytoskeletal proteins. Transglutaminase activity increased in cytoskeletal fractions of activated versus non-activated platelets. Immunoblotting analysis of platelet cytoskeletal fractions identified filamin and vinculin as being crosslinked upon platelet activation.     

Overexpression of epidermal growth factor and hepatocyte growth factor receptors in a proportion of gastrinomas correlates with aggressive growth and lower curability.

PURPOSE: Growth factor receptor expression and activation, particularly for epidermal growth factor (EGF) and hepatocyte growth factor (HGF), in many endocrine and nonendocrine tumors is important in determining tumor recurrence, growth, and aggressiveness. Whether this is true of neuroendocrine tumors such as gastrinomas is unclear. EXPERIMENTAL DESIGN: To address this question, we analyzed the extent of EGFR and HGFR expression in gastrinomas from 38 patients with Zollinger-Ellison syndrome and correlated it with clinical and tumor characteristics. EGFR (n = 38) and HGFR (n = 22) mRNA levels were determined by competitive PCR, and immunohistochemistry was performed on a subset. RESULTS: In each of the gastrinomas studied, detectable levels of EGFR and HGFR mRNA were present. Low levels of EGFR protein expression were detected in 40% of gastrinomas and HGFR protein expression in 90%. EGFR mRNA expression varied by 1050-fold and HGFR by 375-fold. Eighteen percent of gastrinomas overexpressed EGFR mRNA and 14% overexpressed HGFR mRNA, compared with normal pancreas. Maximal EGFR and HGFR mRNA levels were 4- and 1.2-fold increased and correlated with the presence of liver metastases (P = 0.034) and decreased long-term curability (P = 0.027) but not tumor location, size, or tumor functional characteristics. CONCLUSIONS: These above results indicate that EGFR and HGFR mRNA are universally expressed in gastrinomas. Furthermore, each is overexpressed in a minority (15-20%) of the gastrinomas, and the overexpression correlates with aggressive growth and lower curability.     

Hyperbilirubinemia, hypocarbia and periventricular leukomalacia in preterm infants: relationship to cerebral palsy

This study comprised 103 preterm infants with a gestational age less than 33 weeks who were born in Tampere University Hospital and who were followed up to two years of age. Sixty-four perinatal variables were compared to ultrasound findings in the neonatal period and neurologic handicap at the age of two years. Duration of hypocarbia (PCO2 < or = 30 mmHg) during the first 72 h and hyperbilirubinemia (the mean level of serum total bilirubin) at three days of age were independently and significantly related to periventricular leukomalacia, but not directly to cerebral palsy. The only perinatal variables related independently and significantly to cerebral palsy at two years of age were periventricular leukomalacia and ventriculomegaly. According to these results, periventricular leukomalacia was the main predictor of cerebral palsy in preterm infants. In addition to hypocarbia, hyperbilirubinemia may also be involved in the pathogenesis of extensive (severe cystic) periventricular leukomalacia.