660 research outputs found
La prevenzione del tromboembolismo nella fibrillazione atriale non reumatica
No full textRandomized clinical trials have demonstrated the efficacy and safety of oral anticoagulants in the prevention of systemic thromboembolism in nonrheumatic atrial fibrillation. The benefit of this treatment is particularly evident in patients in whom atrial fibrillation is associated with a major risk factor for systemic thromboembolism (patients > 75 years of age, history of hypertension, previous left ventricular failure or previous systemic thromboembolism) or those in whom two minor risk factors are present (patients between 65 and 75 years of age, diabetes, ischemic heart disease). According to these recommendations, all the patients > 75 years of age with chronic or paroxysmal atrial fibrillation should receive oral anticoagulant treatment to maintain an INR between 2.0 and 3.0. However, as the risk of bleeding during oral anticoagulant treatment increases with age, the benefit/risk ratio should always be evaluated in elderly patients. Although high risk patients do not benefit from aspirin treatment, aspirin or other antiplatelet agents might be indicated in medium risk patients or in those in whom the risk of bleeding with oral anticoagulants is considered too high. New antithrombotic regimens will be tested in the near future
STUDIES ON ROLE OF HAEMODYNAMIC AND AUTONOMOUS NERVOUS SYSTEM CHANGES IN PATIENTS WITH OBSTRUCTIVE SLEEP APNOEA
No full textObstructive sleep apnea syndrome (OSAS) is a well established risk factor for
hypertension and is associated with an enhanced sympathetic activity. In this series of
studies we described the pathophysiological changes of blood pressure and autonomous
nervous system activity in patients with OSAS.
We demonstrated that CPAP can modulate the autonomous nervous activity by reducing
the sympathetic discharge as seen by a reduction of blood pressure variability.
In a cohort of 78 patients (76.9%male, 49%hypertensive) a 2 week autoset-CPAP
treatment determined a reduction of systolic BPV (5.3±4.9 vs 4.2±3.4 mmHg, p=0.047)
and pulse rate (78.0±14.5 vs 75.5±15.8 bpm, p=0.032).
An effect on blood pressure, pulse rate and blood pressure variability depends also on
CPAP adherence and, particularly in obese subjects, on pressure's loading effect on the
respiratory system. We studied 16 patients (13males, 47(10)years, BMI 38.5(5.8)kg/m2).
Blood pressure was measured continuously with a Finapres device at increasing CPAP
pressure levels. BP and BPV increased with incremental CPAP (systolic BP r=0.960,
p<0.001, diastolic BP r=0.961, p<0.001; systolic BPV r=0.662,p=0.026; diastolic BPV
r=0.886,p<0.001) and abdominal muscles activity, a surrogate marker of neuro respiratory
drive, correlated with both systolic (r=0.464,p=0.032) and diastolic BP (r=0.747,p=0.009).
As the activity of the autonomous nervous system is mediated by the catecholaminergic
system we hypothesized that the activity of Catechol-O-methyltransferase (COMT), one of
the major mammalian enzymes involved in the metabolic degradation of catecholamines,
measured during drug induced sleep endoscopy (DISE), was altered during intermittent
hypoxia in patients with OSAS.
We recruited 6 patients with OSAS who underwent DISE. During the procedure 7 blood
samples were drown for the analysis of COMT activity and catecholamines concentration
before, during and after an obstructive event. COMT analysis showed an increase of the
enzyme activity after sedation. This was more marked when propofol-induced central
apnea occurred compared to baseline (181.2 (12.8) pmol/min/mg vs 99.4 (11.1)
pmol/min/mg, p<0.05).
In this preliminary analysis we showed that the catecholaminergic system is stimulated
during DISE after apneic events. This might be due to an altered activity of COMT during
hypoxia therefore suggesting a novel pathophysiological pathway responsible of
hypertension in patients with OSAS
L'allergia alimentare nel cane e nel gatto; aspetti clinici, endoscopici ed istopatologici in una casistica di 56 animali.
No full textThe cryoplant for the ITER neutral beam test facility to be built at RFX in Padova, Italy
No full textAssessing the relative potency of (S)- and (R)-warfarin with a new PK-PD model, in relation to VKORC1 genotypes
No full textPurpose. The purpose of this study is to develop a new pharmacokinetic-pharmacodynamic (PK-PD) model to characterise the contribution of (S)- and (R)-warfarin to the anticoagulant
effect on patients in treatment with rac-warfarin.
Methods. Fifty-seven patients starting warfarin (W) therapy were studied, from the first dose and during chronic treatment at INR stabilization. Plasma concentrations of (S)- and (R)-W and INRs were measured 12, 36 and 60 h after the first dose and at steady state 12–14 h after dosing. Patients were also genotyped for the G>A VKORC1 polymorphism. The PK-PD model assumed a linear relationship between W enantiomer concentration and INR and included a scaling factor k to account for a different potency of (R)-W. Two parallel compartment chains with different transit times (MTT1 and MTT2) were used to model the delay in the Weffect. PD parameters were estimated with the maximum likelihood approach.
Results. The model satisfactorily described the mean timecourse of INR, both after the initial dose and during longterm treatment. (R)-W contributed to the rac-Wanticoagulant effect with a potency of about 27% that of (S)-W. This effect was independent of VKORC1 genotype. As expected, the slope of the PK/PD linear correlation increased stepwise from
GG to GA and from GA to AAVKORC1 genotype (0.71, 0.90 and 1.49, respectively).
Conclusions. Our PK-PD linear model can quantify the partial pharmacodynamic activity of (R)-W in patients contemporaneously exposed to therapeutic (S)-W plasma levels. This concept may be useful in improving the performance of future algorithms aiming at identifying the most appropriateWmaintenance dose
Poor comparability of coagulation screening test with specific measurement in patients receiving direct oral anticoagulants: Results from a multicenter/multiplatform study
No full textEssentials Prothrombin and partial thromboplastin time (PT/PTT) measure direct oral anticoagulants (DOACs). PT, PTT and specific tests for DOACs were performed on patients treated for atrial fibrillation. Normal PT/PTT don't exclude DOAC activity and their prolongation doesn't confirm DOAC action. The use of PT or PTT to evaluate DOAC activity could cause dangerous misinterpretations. Summary: Background Prothrombin time (PT) and activated partial thromboplastin time (APTT) have been proposed to measure the effect of oral anti-activated factor X (FXa) or anti-activated FII drugs, respectively. Aims To evaluate the relationships and responsiveness of PT and APTT versus direct oral anticoagulant (DOAC) concentrations measured with specific coagulation tests performed with different platforms in four Italian anticoagulation clinics. Methods Six hundred and thirty-five patients with atrial fibrillation participated in the study: 240 were receiving dabigatran, 264 were receiving rivaroxaban, and 131 were receiving apixaban. Blood was taken at trough and peak within the first month (15–25 days) of treatment. PT, APTT, diluted thrombin time (dTT) calibrated for dabigatran and anti-FXa calibrated for rivaroxaban or apixaban were determined. Results For dabigatran, the correlation between APTT and dTT ranged from r = 0.80 to r = 0.62. For rivaroxaban, the correlation between the anti-FXa assay and PT ranged from r = 0.91 to r = 0.73. For apixaban, the correlation between the anti-FXa assay and PT was lower than for the two other drugs (r = 0.81 to r = 0.54). Despite the above significant correlations, the responsiveness of PT or APTT was relatively poor. A discrepancy between global testing and DOAC plasma concentrations was shown in a considerable proportion of patients, depending on the platform and drug, with values ranging from 6% to 62%. Conclusions Overall, poor responsiveness of the screening tests to DOAC concentrations was observed. PT and APTT normal values cannot exclude DOAC anticoagulant activity, and PT or APTT prolongation is not always associated with DOAC anticoagulant effect as determined with specific tests
Monitoring liver regeneration after right hepatectomy.
No full textFactor VII coagulant, prothrombine time, fibrinogen, prealbumin and a fetoprotein have been evaluated in a patient operated on for right hepatectomy, in order to identify the best markers in prognosing liver regeneration. Factor VII and prothrombine time progressively increased, starting from the 5th-7th day, entering normal range by the 10th and demonstrated a good correlation with both liver scintiscan and ultrasonography. Prealbumin and fibrinogen did not provide any useful information and a fetoprotein levels progressively decreased, demonstrating the complete removal of the neoplastic tissue. Factor VII and prothrombine time seem therefore to be the most reliable markers, among those investigated in this study, of liver regeneration after partial hepatectomy
Echocardiographic prognostic indicators in dogs treated by pulmonary balloon valvuloplasty
No full textMeasuring the magnetic birefringence of vacuum: the PVLAS experiment
No full textWe describe the principle and the status of the PVLAS experiment which is presently running at the INFN section of Ferrara, Italy, to detect the magnetic birefringence of vacuum. This is related to the QED vacuum structure and can be detected by measuring the ellipticity acquired by a linearly polarized light beam propagating through a strong magnetic field. Such an effect is predicted by the Euler–Heisenberg Lagrangian. The method is also sensitive to other hypothetical physical effects such as axion-like particles and in general to any fermion/boson millicharged particle. Here we report on the construction of our apparatus based on a high finesse (> 2 · 10^5) Fabry–Perot cavity and two 0.9 m long 2.5 T permanent dipole rotating magnets, and on the measurements performed on a scaled down test setup. With the test setup we have improved by about a factor 2 the limit on the parameter A_e describing nonlinear electrodynamic effects in vacuum: A_e < 2.9 · 10^−21 T^−2 @ 95% C.L
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