Dispersion of ventricular repolarization in the long QT syndrome

To identify markers of dispersion of the ventricular repolarization in the idiopathic long QT syndrome, body surface potential maps were analyzed in 40 such patients (mean age +/- standard deviation 21 +/- 11 years) and in 30 healthy control subjects (mean age 24 +/- 7 years). In each subject, 117 chest leads were recorded and maps of the integral values of the QRST interval were calculated. A multipolar distribution of the values, a marker of gross electrical inequalities of repolarization, was found only in 4 patients. To detect minor regional disparities of ventricular recovery, all the ST-T waveforms were analyzed in each subject. The ST-T waves were represented by a discrete series of potential values. The "similarity index" was computed by applying a principal component analysis, which represents (in percent) to what extent 1 fundamental pattern of ST-T reproduces all the recorded waveforms. The mean value of the similarity index was significantly lower in patients with long QT syndrome than in control subjects (49 +/- 10 vs 77 +/- 8%, p less than 0.0001). A value less than 61% (corresponding to 2 standard deviations below the mean value for controls) was found in 35 of 40 patients and in only 1 control subject (sensitivity 87%, specificity 96%). Thus, the similarity index is a more sensitive marker than the multipolar distribution of QRST integral maps in revealing electrical disparities of the ventricular recovery times.(ABSTRACT TRUNCATED AT 250 WORDS)

Re-designing the substrate binding pocket of laccase for enhanced oxidation of sinapic acid

Iterative saturation mutagenesis was performed over six residues delimiting the substrate binding pocket of a high redox potential chimeric laccase with the aim of enhancing its activity over sinapic acid, a lignin-related phenol of industrial interest.

Development of a PCR for Borrelia burgdorferi sensu lato, targeted on the groEL gene

Borrelia burgdorferi sensu lato (s.l.) is the etiological agent of Lyme disease, transmitted by ticks of the genus Ixodes Latreille. Diagnosis of Lyme disease in humans is often difficult and a detailed knowledge of the circulation of B. burgdorferi s.l. in tick hosts is therefore fundamental to support clinical procedures. Here we developed a molecular approach for the detection of B. burgdorferi s.l. in North Italian Ixodes ricinus (Linnaeus). The method is based on the amplification of a fragment of the groEL gene, which encodes a heat-shock protein highly conserved among B. burgdorferi s.l. species. The tool was applied in both qualitative and Real-time PCR approaches testing ticks collected in a North Italian area. The obtained results suggest that this new molecular tool could represent a sensitive and specific method for epidemiological studies aimed at defining the distribution of B. burgdorferi s.l. in I. ricinus and, consequently, the exposure risk for humans.

Utility of the Ratio between Lactate Dehydrogenase (LDH) Activity and Total Nucleated Cell Counts in Effusions (LDH/TNCC Ratio) for the Diagnosis of Feline Infectious Peritonitis (FIP)

Background: We tested the hypothesis that the ratio between lactate dehydrogenase activity (LDH) and total nucleated cell counts (TNCC) in effusions may be useful to diagnose feline infectious peritonitis (FIP). Methods: LDH/TNCC ratio was retrospectively evaluated in 648 effusions grouped based on cytology and physicochemical analysis (step 1), on the probability of FIP estimated by additional tests on fluids (step 2) or on other biological samples (step 3, n = 471). Results of different steps were statistically compared. Receiver Operating Characteristic (ROC) curves were designed to assess whether the ratio identify the samples with FIP “probable/almost confirmed”. The cut-offs with the highest positive likelihood ratio (LR+) or Youden Index (YI) or with equal sensitivity and specificity were determined. Results: A high median LDH/TNCC ratio was found in FIP effusions (step1: 2.01) and with probable or almost confirmed FIP (step 2: 1.99; 2.20 respectively; step 3: 1.26; 2.30 respectively). The optimal cut-offs were 7.54 (LR+ 6.58), 0.62 (IY 0.67, sensitivity: 89.1%; specificity 77.7%), 0.72 (sensitivity and specificity: 79.2%) in step 2 and 2.27 (LR+ 10.39), 0.62 (IY 0.65, sensitivity: 82.1%; specificity 83.0%), 0.54 (sensitivity: 82.1%; specificity 81.9%) in step 3. Conclusions: a high LDH/TNCC ratio support a FIP diagnosis.