93 results on '"Rapetti F"'
Search Results
52. The mortar edge element method on non‐matching grids for eddy current calculations in moving structures
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Rapetti, F., primary
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- 2001
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53. Calculation of eddy currents with edge elements on non-matching grids in moving structures
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Razek, A., primary, Maday, Y., additional, Buffa, A., additional, Santandrea, L., additional, Bouillault, E., additional, and Rapetti, F., additional
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- 2000
- Full Text
- View/download PDF
54. Calculation of eddy currents in moving structures by a sliding mesh-finite element method
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Rapetti, F., primary, Maday, Y., additional, and Buffa, A., additional
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- 2000
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- View/download PDF
55. Calculation of eddy currents in moving structures using a finite element method on non‐matching grids
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Rapetti, F., primary, Santandrea, L., additional, Bouillault, F., additional, and Razek, A., additional
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- 2000
- Full Text
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56. THE MORTAR EDGE ELEMENT METHOD IN THREE DIMENSIONS:APPLICATION TO MAGNETOSTATICS.
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Bouillault, F., Buffa, A., Maday, Y., and Rapetti, F.
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APPROXIMATION theory ,MAGNETOSTATICS ,MAGNETIC fields ,INTERFACES (Physical sciences) - Abstract
Studies the edge element approximation on nonmatching grids of a given magnetostatic problem in three dimensions. Focus on the description of the magnetic field distribution in a domain composed of two solid parts separated by an interface; Description of the three-dimensional mortar edge element method and its main implementation aspects.
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- 2003
- Full Text
- View/download PDF
57. Calculation of Eddy Currents with Edge Elements on Non-Matching Grids in Moving Structures.
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Rapetti, F. and Bouillault, F.
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EDDY currents (Electric) , *ELECTROMAGNETIC devices - Abstract
Presents information on a study which examined the proposed method for calculating the movement in electromagnet devices. Mathematical model for eddy current problems; Results and discussion; Conclusions.
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- 2000
58. Function approximation on triangular grids: some numerical results using adaptive techniques
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Manzi, C., Rapetti, F., and Formaggia, L.
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- 2000
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59. Aspetti climatici del lago di Massaciuccoli in rapporto alla presenza di entità vegetali di rilevanza fitogeografica
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Rapetti, F., Tomei, Paolo, and Vittorini, S.
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- 1987
60. Indagini sulle zone unide della Toscana. XX. Le sfagnete di San Lorenzo a Vaccoli nel Monte Pisano (Toscana nord-occidentale. Aspetti microclimatici
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Tomei, Paolo, Rapetti, F., and Ficini, G.
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- 1984
61. IL DEFLUSSO LIQUIDO E TORBIDO DEL TORRENTE ROGLIO (BACINO DELL'ARNO) RELATIVI AL 1977, IN RELAZIONE AI PROCESSI DI EROSIONE NELLE ARGILLE PLIOCENICHE
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Rapetti, Franco and Rapetti, F.
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- 1979
62. Simulation of a coupled magneto-mechanical system through the sliding-mesh mortar element method
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Rapetti, F., Annalisa Buffa, Bouillault, F., and Maday, Y.
63. Simulation of a magneto-mechanical damping machine: analysis, discretization, results
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Bouillault, F., Annalisa Buffa, Maday, Y., and Rapetti, F.
64. A sliding mesh-mortar method for a two dimensional eddy currents model of electric engines
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Annalisa Buffa, Maday, Y., and Rapetti, F.
65. Zoning and mapping landslide hazard in the Castelnuovo di Garfagnana region (Tuscany, Italy)
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Margottini C, Canuti P., Federici, P. R., Puccinelli, Alberto, Amato Avanzi, Giacomo D., Falaschi, F., Giannecchini, Roberto, Marchetti, D., Pochini, A., Rapetti, F., and Adriano Ribolini
66. Extracorporeal CO2 Removal
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Francesco Vasques, Francesca Collino, Michael Quintel, Luciano Gattinoni, Francesca Rapetti, Iacopo Pasticci, Tommaso Tonetti, Tim Behnemann, Francesco Cipulli, Onnen Moerer, Federica Romitti, Julia Niewenhuys, Eleonora Duscio, Francesco Vassalli, Verena Reupke, Duscio E., Cipulli F., Vasques F., Collino F., Rapetti F., Romitti F., Behnemann T., Niewenhuys J., Tonetti T., Pasticci I., Vassalli F., Reupke V., Moerer O., Quintel M., and Gattinoni L.
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Catheterization, Central Venous ,minimally invasive extracorporeal life support ,Swine ,medicine.medical_treatment ,030204 cardiovascular system & hematology ,Lung injury ,Critical Care and Intensive Care Medicine ,Extracorporeal ,pCO2 ,Artificial lung ,03 medical and health sciences ,0302 clinical medicine ,030202 anesthesiology ,medicine ,Animals ,carbon dioxide removal ,Mechanical ventilation ,Lung ,business.industry ,ventilator-induced lung injury ,Blood flow ,Carbon Dioxide ,acute respiratory distress syndrome ,extracorporeal membrane oxygenation ,3. Good health ,extracorporeal carbon dioxide removal ,Catheter ,medicine.anatomical_structure ,Anesthesia ,Models, Animal ,Respiratory Insufficiency ,business ,Ventilator Weaning - Abstract
Objectives Minimally invasive extracorporeal CO2 removal is an accepted supportive treatment in chronic obstructive pulmonary disease patients. Conversely, the potential of such technique in treating acute respiratory distress syndrome patients remains to be investigated. The aim of this study was: 1) to quantify membrane lung CO2 removal (VCO2ML) under different conditions and 2) to quantify the natural lung CO2 removal (VCO2NL) and to what extent mechanical ventilation can be reduced while maintaining total expired CO2 (VCO2tot = VCO2ML + VCO2NL) and arterial PCO2 constant. Design Experimental animal study. Setting Department of Experimental Animal Medicine, University of Gottingen, Germany. Subjects Eight healthy pigs (57.7 ± 5 kg). Interventions The animals were sedated, ventilated, and connected to the artificial lung system (surface 1.8 m, polymethylpentene membrane, filling volume 125 mL) through a 13F catheter. VCO2ML was measured under different combinations of inflow PCO2 (38.9 ± 3.3, 65 ± 5.7, and 89.9 ± 12.9 mm Hg), extracorporeal blood flow (100, 200, 300, and 400 mL/min), and gas flow (4, 6, and 12 L/min). At each setting, we measured VCO2ML, VCO2NL, lung mechanics, and blood gases. Measurements and main results VCO2ML increased linearly with extracorporeal blood flow and inflow PCO2 but was not affected by gas flow. The outflow PCO2 was similar regardless of inflow PCO2 and extracorporeal blood flow, suggesting that VCO2ML was maximally exploited in each experimental condition. Mechanical ventilation could be reduced by up to 80-90% while maintaining a constant PaCO2. Conclusions Minimally invasive extracorporeal CO2 removal removes a relevant amount of CO2 thus allowing mechanical ventilation to be significantly reduced depending on extracorporeal blood flow and inflow PCO2. Extracorporeal CO2 removal may provide the physiologic prerequisites for controlling ventilator-induced lung injury.
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- 2019
67. Positive End-expiratory Pressure and Mechanical Power
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Peter Herrmann, Karin Holke, Verena Reupke, Giorgia Maiolo, Francesco Cipulli, Günter Hahn, Tommaso Tonetti, Luigi Camporota, John J. Marini, Julia Niewenhuys, Francesca Collino, Francesca Rapetti, Francesco Vasques, Tim Behnemann, Michael Quintel, Onnen Moerer, Luciano Gattinoni, Eleonora Duscio, Federica Romitti, Collino F., Rapetti F., Vasques F., Maiolo G., Tonetti T., Romitti F., Niewenhuys J., Behnemann T., Camporota L., Hahn G., Reupke V., Holke K., Herrmann P., Duscio E., Cipulli F., Moerer O., Marini J.J., Quintel M., and Gattinoni L.
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medicine.medical_specialty ,Lung ,VILI ,Swine ,business.industry ,Ventilator-Induced Lung Injury ,Lung injury ,respiratory system ,Positive-Pressure Respiration ,Disease Models, Animal ,03 medical and health sciences ,0302 clinical medicine ,Anesthesiology and Pain Medicine ,medicine.anatomical_structure ,030202 anesthesiology ,Internal medicine ,medicine ,Cardiology ,Animals ,business ,030217 neurology & neurosurgery ,Positive end-expiratory pressure ,Mechanical energy - Abstract
EDITOR’S PERSPECTIVEWhat We Already Know about This TopicPositive end-expiratory pressure protects against ventilation-induced lung injury by improving homogeneity of ventilation, but positive end-expiratory pressure contributes to the mechanical power required to ventilate the lungWhat This Article Tells Us That Is NewThis in vivo study (36 pigs mechanically ventilated in the prone position) suggests that low levels of positive end-expiratory pressure reduce injury associated with atelectasis, and above a threshold level of power, positive end-expiratory pressure causes lung injury and adverse hemodynamicsBackgroundPositive end-expiratory pressure is usually considered protective against ventilation-induced lung injury by reducing atelectrauma and improving lung homogeneity. However, positive end-expiratory pressure, together with tidal volume, gas flow, and respiratory rate, contributes to the mechanical power required to ventilate the lung. This study aimed at investigating the effects of increasing mechanical power by selectively modifying its positive end-expiratory pressure component.MethodsThirty-six healthy piglets (23.3 ± 2.3 kg) were ventilated prone for 50 h at 30 breaths/min and with a tidal volume equal to functional residual capacity. Positive end-expiratory pressure levels (0, 4, 7, 11, 14, and 18 cm H2O) were applied to six groups of six animals. Respiratory, gas exchange, and hemodynamic variables were recorded every 6 h. Lung weight and wet-to-dry ratio were measured, and histologic samples were collected.ResultsLung mechanical power was similar at 0 (8.8 ± 3.8 J/min), 4 (8.9 ± 4.4 J/min), and 7 (9.6 ± 4.3 J/min) cm H2O positive end-expiratory pressure, and it linearly increased thereafter from 15.5 ± 3.6 J/min (positive end-expiratory pressure, 11 cm H2O) to 18.7 ± 6 J/min (positive end-expiratory pressure, 14 cm H2O) and 22 ± 6.1 J/min (positive end-expiratory pressure, 18 cm H2O). Lung elastances, vascular congestion, atelectasis, inflammation, and septal rupture decreased from zero end-expiratory pressure to 4 to 7 cm H2O (P < 0.0001) and increased progressively at higher positive end-expiratory pressure. At these higher positive end-expiratory pressure levels, striking hemodynamic impairment and death manifested (mortality 0% at positive end-expiratory pressure 0 to 11 cm H2O, 33% at 14 cm H2O, and 50% at 18 cm H2O positive end-expiratory pressure). From zero end-expiratory pressure to 18 cm H2O, mean pulmonary arterial pressure (from 19.7 ± 5.3 to 32.2 ± 9.2 mmHg), fluid administration (from 537 ± 403 to 2043 ± 930 ml), and noradrenaline infusion (0.04 ± 0.09 to 0.34 ± 0.31 μg · kg−1 · min−1) progressively increased (P < 0.0001). Lung weight and lung wet-to-dry ratios were not significantly different across the groups. The lung mechanical power level that best discriminated between more versus less severe damage was 13 ± 1 J/min.ConclusionsLess than 7 cm H2O positive end-expiratory pressure reduced atelectrauma encountered at zero end-expiratory pressure. Above a defined power threshold, sustained positive end-expiratory pressure contributed to potentially lethal lung damage and hemodynamic impairment.
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- 2019
68. Monitoring lung impedance changes during long-term ventilator-induced lung injury ventilation using electrical impedance tomography
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G Maiolo, Francesco Vasques, O Moerer, A Just, F Rapetti, T Behnemann, Günter Hahn, J Niewenhuys, Michael Quintel, L Gattinoni, Federica Romitti, F Collino, Tommaso Tonetti, Hahn G., Niewenhuys J., Just A., Tonetti T., Behnemann T., Rapetti F., Collino F., Vasques F., Maiolo G., Romitti F., Gattinoni L., Quintel M., and Moerer O.
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Time Factors ,Materials science ,Time Factor ,Lung impedance ,Swine ,Physiology ,Ventilator-Induced Lung Injury ,0206 medical engineering ,Biomedical Engineering ,Biophysics ,02 engineering and technology ,Lung injury ,Absolute electrical impedance tomography ,Imaging phantom ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,Electric Impedance ,medicine ,Animals ,Tissue electrical propertie ,Tomography ,Electrical impedance tomography ,Monitoring, Physiologic ,Image reconstruction ,Lung resistivity ,Lung water ,Tissue electrical properties ,Lung ,Animal ,business.industry ,Exhalation ,respiratory system ,020601 biomedical engineering ,respiratory tract diseases ,medicine.anatomical_structure ,Reference measurement ,Nuclear medicine ,business ,030217 neurology & neurosurgery - Abstract
Objective The target of this methodological evaluation was the feasibility of long-term monitoring of changes in lung conditions by time-difference electrical impedance tomography (tdEIT). In contrast to ventilation monitoring by tdEIT, the monitoring of end-expiratory (EELIC) or end-inspiratory (EILIC) lung impedance change always requires a reference measurement. Approach To determine the stability of the used Pulmovista 500® EIT system, as a prerequisite it was initially secured on a resistive phantom for 50 h. By comparing the slopes of EELIC for the whole lung area up to 48 h from 36 pigs ventilated at six positive end-expiratory pressure (PEEP) levels from 0 to 18 cmH2O we found a good agreement (range of r 2 = 0.93-1.0) between absolute EIT (aEIT) and tdEIT values. This justified the usage of tdEIT with its superior local resolution compared to aEIT for long-term determination of EELIC. Main results The EELIC was between -0.07 Ωm day-1 at PEEP 4 and -1.04 Ωm day-1 at PEEP 18 cmH2O. The complex local time pattern for EELIC was roughly quantified by the new parameter, centre of end-expiratory change (CoEEC), in equivalence to the established centre of ventilation (CoV). The ventrally located mean of the CoV was fairly constant in the range of 42%-46% of thorax diameter; however, on the contrary, the CoEEC shifted from about 40% to about 75% in the dorsal direction for PEEP levels of 14 and 18 cmH2O. Significance The observed shifts started earlier for higher PEEP levels. Changes of EELI could be precisely monitored over a period of 48 h by tdEIT on pigs.
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- 2020
69. Reclassifying acute respiratory distress syndrome
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Michael Quintel, Francesca Collino, Francesco Vasques, Peter Herrmann, Tim Friede, Onnen Moerer, Giorgia Maiolo, Massimo Cressoni, Francesca Rapetti, Davide Chiumello, Luciano Gattinoni, Tommaso Tonetti, Federica Romitti, Maiolo G., Collino F., Vasques F., Rapetti F., Tonetti T., Romitti F., Cressoni M., Chiumello D., Moerer O., Herrmann P., Friede T., Quintel M., and Gattinoni L.
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Pulmonary and Respiratory Medicine ,ARDS ,medicine.medical_treatment ,Acute respiratory distress ,Critical Care and Intensive Care Medicine ,03 medical and health sciences ,0302 clinical medicine ,Mechanical ventilation ,medicine ,Extracorporeal membrane oxygenation ,Lung inhomogeneity ,Acute respiratory distress syndrome ,business.industry ,Ct analysis ,030208 emergency & critical care medicine ,computed tomographic analysis ,Computed tomographic analysi ,respiratory system ,medicine.disease ,acute respiratory distress syndrome ,extracorporeal membrane oxygenation ,lung inhomogeneity ,mechanical ventilation ,respiratory tract diseases ,030228 respiratory system ,Anesthesia ,business ,circulatory and respiratory physiology - Abstract
Rationale: The ratio of PaO2 to FIO2 (P/F) defines acute respiratory distress syndrome (ARDS) severity and suggests appropriate therapies. Objectives: We investigated 1) whether a 150-mm-Hg P/F threshold within the range of moderate ARDS (100-200 mm Hg) would define two subgroups that were more homogeneous; and 2) which criteria led the clinicians to apply extracorporeal membrane oxygenation (ECMO) in severe ARDS. Methods: At the 150-mm-Hg P/F threshold, moderate patients were split into mild-moderate (n = 50) and moderate-severe (n = 55) groups. Patients with severe ARDS (FIO2 not available in three patients) were split into higher (n = 63) and lower (n = 18) FIO2 groups at an 80% FIO2 threshold. Measurements and Main Results: Compared with mild- moderate ARDS, patients with moderate-severe ARDS had higher peak pressures, PaCO2, and pH. They also had heavier lungs, greater inhomogeneity, more noninflated tissue, and greater lung recruitability. Within 84 patients with severe ARDS (P/F,100 mm Hg), 75% belonged to the higher FIO2 subgroup. They differed from the patients with severe ARDS with lower FIO2 only in PaCO2 and lung weight. Forty-one of 46 patients treated with ECMO belonged to the higher FIO2 group. Within this group, the patients receiving ECMO had higher PaCO2 than the 22 non-ECMO patients. The inhomogeneity ratio, total lung weight, and noninflated tissue were also significantly higher. Conclusions: Using the 150-mm-Hg P/F threshold gave a more homogeneous distribution of patients with ARDS across the severity subgroups and identified two populations that differed in their anatomical and physiological characteristics. The patients treated with ECMO belonged to the severe ARDS group, and almost 90% of them belonged to the higher FIO2 subgroup.
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- 2018
70. Driving pressure and mechanical power: new targets for VILI prevention
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Francesco Vasques, Paolo Cadringher, Giorgia Maiolo, Francesca Rapetti, Michael Quintel, Luciano Gattinoni, Federica Romitti, Massimo Cressoni, Luigi Camporota, Francesca Collino, Tommaso Tonetti, Tonetti T., Vasques F., Rapetti F., Maiolo G., Collino F., Romitti F., Camporota L., Cressoni M., Cadringher P., Quintel M., and Gattinoni L.
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medicine.medical_specialty ,Atelectrauma ,Barotrauma ,Driving pressure ,Ergotrauma ,Mechanical power ,Mechanical ventilation ,Ventilator-induced lung injury (VILI) ,Volutrauma ,Respiratory rate ,medicine.medical_treatment ,Review Article ,Lung injury ,03 medical and health sciences ,Plateau pressure ,0302 clinical medicine ,Internal medicine ,medicine ,Respiratory system ,Mechanical energy ,Tidal volume ,Chemistry ,030208 emergency & critical care medicine ,General Medicine ,respiratory system ,Surgery ,respiratory tract diseases ,030228 respiratory system ,Volume (thermodynamics) ,Cardiology - Abstract
Several factors have been recognized as possible triggers of ventilator-induced lung injury (VILI). The first is pressure (thus the ‘barotrauma’), then the volume (hence the ‘volutrauma’), finally the cyclic opening-closing of the lung units (‘atelectrauma’). Less attention has been paid to the respiratory rate and the flow, although both theoretical considerations and experimental evidence attribute them a significant role in the generation of VILI. The initial injury to the lung parenchyma is necessarily mechanical and it could manifest as an unphysiological distortion of the extracellular matrix and/or as micro-fractures in the hyaluronan, likely the most fragile polymer embedded in the matrix. The order of magnitude of the energy required to break a molecular bond between the hyaluronan and the associated protein is 1.12×10 -16 Joules (J), 70–90% higher than the average energy delivered by a single breath of 1L assuming a lung elastance of 10 cmH 2 O/L (0.5 J). With a normal statistical distribution of the bond strength some polymers will be exposed each cycle to an energy large enough to rupture. Both the extracellular matrix distortion and the polymer fractures lead to inflammatory increase of capillary permeability with edema if a pulmonary blood flow is sufficient. The mediation analysis of higher vs. lower tidal volume and PEEP studies suggests that the driving pressure, more than tidal volume, is the best predictor of VILI, as inferred by increased mortality. This is not surprising, as both tidal volume and respiratory system elastance (resulting in driving pressure) may independently contribute to the mortality. For the same elastance driving pressure is a predictor similar to plateau pressure or tidal volume. Driving pressure is one of the components of the mechanical power, which also includes respiratory rate, flow and PEEP. Finding the threshold for mechanical power would greatly simplify assessment and prevention of VILI.
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- 2017
71. Volutrauma, Atelectrauma, and Mechanical Power
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Luciano Gattinoni, Francesca Rapetti, Francesca Collino, Giorgia Maiolo, Tommaso Tonetti, Michael Quintel, Massimo Cressoni, Tonetti T., Cressoni M., Collino F., Maiolo G., Rapetti F., Quintel M., and Gattinoni L.
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Respiratory Distress Syndrome ,VILI ,business.industry ,Ventilator-Induced Lung Injury ,MEDLINE ,030208 emergency & critical care medicine ,Critical Care and Intensive Care Medicine ,computer.software_genre ,Respiration, Artificial ,Article ,03 medical and health sciences ,0302 clinical medicine ,030228 respiratory system ,Medicine ,Humans ,Artificial intelligence ,business ,computer ,Natural language processing ,Mechanical energy - Published
- 2017
72. Positive end-expiratory pressure: How to set it at the individual level
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Michael Quintel, Federica Romitti, Francesca Collino, Tommaso Tonetti, Francesco Vasques, Francesca Rapetti, Luciano Gattinoni, Giorgia Maiolo, Gattinoni L., Collino F., Maiolo G., Rapetti F., Romitti F., Tonetti T., Vasques F., and Quintel M.
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medicine.medical_specialty ,medicine.medical_treatment ,Review Article ,Pulmonary compliance ,Lung injury ,mechanical ventilation ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Intensive care medicine ,Positive end-expiratory pressure ,Mechanical ventilation ,Lung ,business.industry ,Oxygen transport ,030208 emergency & critical care medicine ,General Medicine ,Oxygenation ,respiratory system ,lung recruitment ,respiratory tract diseases ,Compliance (physiology) ,Positive end-expiratory pressure (PEEP) ,medicine.anatomical_structure ,030228 respiratory system ,business ,circulatory and respiratory physiology - Abstract
The positive end-expiratory pressure (PEEP), since its introduction in the treatment of acute respiratory failure, up to the 1980s was uniquely aimed to provide a viable oxygenation. Since the first application, a large debate about the criteria for selecting the PEEP levels arose within the scientific community. Lung mechanics, oxygen transport, venous admixture thresholds were all proposed, leading to PEEP recommendations from 5 up to 25 cmH 2 O. Throughout this period, the main concern was the hemodynamics. This paradigm changed during the 1980s after the wide acceptance of atelectrauma as one of the leading causes of ventilator induced lung injury. Accordingly, the PEEP aim shifted from oxygenation to lung protection. In this framework, the prevention of lung opening and closing became an almost unquestioned dogma. Consequently, as PEEP keeps open the pulmonary units opened during the previous inspiratory phase, new methods were designed to identify the ‘optimal’ PEEP during the expiratory phase. The open lung approach requires that every collapsed unit potentially openable is opened and maintained open. The methods to assess the recruitment are based on imaging (computed tomography, electric impedance tomography, ultrasound) or mechanically-driven gas exchange modifications. All the latest assume that whatever change in respiratory system compliance is due to changes in lung compliance, which in turn is uniquely function of the recruitment. Comparative studies, however, showed that the only possible approach to measure the amount of collapsed tissue regaining inflation is the CT scan. In fact, all the other methods estimate as recruitment the gas entry in pulmonary units already open at lower PEEP, but increasing their compliance at higher PEEP. Since higher PEEP is usually more indicated (also for oxygenation) when the recruitability is higher, as occurs with increasing severity, a meaningful PEEP selection requires the assessment of recruitment. The Berlin definition may help in this assessment.
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- 2017
73. The future of mechanical ventilation: Lessons from the present and the past
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Francesca Collino, Francesco Vasques, John J. Marini, Luciano Gattinoni, Michael Quintel, Giorgia Maiolo, Tommaso Tonetti, Francesca Rapetti, Gattinoni L., Marini J.J., Collino F., Maiolo G., Rapetti F., Tonetti T., Vasques F., and Quintel M.
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ARDS ,medicine.medical_treatment ,Review ,Lung injury ,Critical Care and Intensive Care Medicine ,Artificial lung ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Mechanical ventilation ,law ,Tidal Volume ,Humans ,Medicine ,Lung volumes ,Tidal volume ,Mechanical power ,Ventilator-induced lung injury ,Respiratory Distress Syndrome ,Acute respiratory distress syndrome ,Extracorporeal membrane oxygenation ,business.industry ,lcsh:Medical emergencies. Critical care. Intensive care. First aid ,030208 emergency & critical care medicine ,lcsh:RC86-88.9 ,respiratory system ,medicine.disease ,Respiration, Artificial ,3. Good health ,respiratory tract diseases ,Barotrauma ,030228 respiratory system ,Anesthesia ,Ventilation (architecture) ,Respiratory Mechanics ,business ,Forecasting ,Transpulmonary pressure - Abstract
The adverse effects of mechanical ventilation in acute respiratory distress syndrome (ARDS) arise from two main causes: unphysiological increases of transpulmonary pressure and unphysiological increases/decreases of pleural pressure during positive or negative pressure ventilation. The transpulmonary pressure-related side effects primarily account for ventilator-induced lung injury (VILI) while the pleural pressure-related side effects primarily account for hemodynamic alterations. The changes of transpulmonary pressure and pleural pressure resulting from a given applied driving pressure depend on the relative elastances of the lung and chest wall. The term ‘volutrauma’ should refer to excessive strain, while ‘barotrauma’ should refer to excessive stress. Strains exceeding 1.5, corresponding to a stress above ~20 cmH2O in humans, are severely damaging in experimental animals. Apart from high tidal volumes and high transpulmonary pressures, the respiratory rate and inspiratory flow may also play roles in the genesis of VILI. We do not know which fraction of mortality is attributable to VILI with ventilation comparable to that reported in recent clinical practice surveys (tidal volume ~7.5 ml/kg, positive end-expiratory pressure (PEEP) ~8 cmH2O, rate ~20 bpm, associated mortality ~35%). Therefore, a more complete and individually personalized understanding of ARDS lung mechanics and its interaction with the ventilator is needed to improve future care. Knowledge of functional lung size would allow the quantitative estimation of strain. The determination of lung inhomogeneity/stress raisers would help assess local stresses; the measurement of lung recruitability would guide PEEP selection to optimize lung size and homogeneity. Finding a safety threshold for mechanical power, normalized to functional lung volume and tissue heterogeneity, may help precisely define the safety limits of ventilating the individual in question. When a mechanical ventilation set cannot be found to avoid an excessive risk of VILI, alternative methods (such as the artificial lung) should be considered.
- Published
- 2017
74. Scale-invariance laws in the recurrence interval of extreme floods: an application to the upper Po river valley (northern Italy)
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Adriano Mazzarella, Franco Rapetti, Mazzarella, Adriano, and Rapetti, F.
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Hydrology ,River valley ,Geography ,Flood myth ,Law ,Meteorological observatory ,Statistical analysis ,Scale invariance ,Water Science and Technology ,Northern italy - Abstract
The floods that have occurred in the upper valley of the Po river (northern Italy) were classified according to an index of strength on the basis of documentary sources available at the meteorological observatory of Moncalieri since 1780. The catalogue was ascertained to be complete only for events classified at least as moderate. Application of Cantor dust statistics and rank-ordering statistics to time-occurrences of floods provided significant evidence of scale-invariance laws that might be very helpful in assessing and reducing future hazards. The increase in the fractal dimension for floods occurring after 1890 is here related to the significant increase in the number of very heavy rainfall episodes measured all over Italy.
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- 2004
75. PDE4D: A Multipurpose Pharmacological Target.
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Lusardi M, Rapetti F, Spallarossa A, and Brullo C
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- Humans, Animals, Neurodegenerative Diseases drug therapy, Neurodegenerative Diseases metabolism, Neoplasms drug therapy, Neoplasms metabolism, Cyclic Nucleotide Phosphodiesterases, Type 4 metabolism, Phosphodiesterase 4 Inhibitors pharmacology, Phosphodiesterase 4 Inhibitors therapeutic use, Phosphodiesterase 4 Inhibitors chemistry
- Abstract
Phosphodiesterase 4 (PDE4) enzymes catalyze cyclic adenosine monophosphate (cAMP) hydrolysis and are involved in a variety of physiological processes, including brain function, monocyte and macrophage activation, and neutrophil infiltration. Among different PDE4 isoforms, Phosphodiesterases 4D (PDE4Ds) play a fundamental role in cognitive, learning and memory consolidation processes and cancer development. Selective PDE4D inhibitors (PDE4Dis) could represent an innovative and valid therapeutic strategy for the treatment of various neurodegenerative diseases, such as Alzheimer's, Parkinson's, Huntington's, and Lou Gehrig's diseases, but also for stroke, traumatic brain and spinal cord injury, mild cognitive impairment, and all demyelinating diseases such as multiple sclerosis. In addition, small molecules able to block PDE4D isoforms have been recently studied for the treatment of specific cancer types, particularly hepatocellular carcinoma and breast cancer. This review overviews the PDE4DIsso far identified and provides useful information, from a medicinal chemistry point of view, for the development of a novel series of compounds with improved pharmacological properties.
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- 2024
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- View/download PDF
76. Investigations of Antioxidant and Anti-Cancer Activities of 5-Aminopyrazole Derivatives.
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Rapetti F, Spallarossa A, Russo E, Caviglia D, Villa C, Tasso B, Signorello MG, Rosano C, Iervasi E, Ponassi M, and Brullo C
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- Humans, Structure-Activity Relationship, Cell Line, Tumor, Cell Proliferation drug effects, Molecular Structure, Pyrazoles chemistry, Pyrazoles pharmacology, Pyrazoles chemical synthesis, Antineoplastic Agents pharmacology, Antineoplastic Agents chemistry, Antioxidants pharmacology, Antioxidants chemistry
- Abstract
To further extend the structure-activity relationships (SARs) of 5-aminopyrazoles (5APs) and identify novel compounds able to interfere with inflammation, oxidative stress, and tumorigenesis, 5APs 1-4 have been designed and prepared. Some chemical modifications have been inserted on cathecol function or in aminopyrazole central core; in detail: (i) smaller, bigger, and more lipophilic substituents were introduced in meta and para positions of catechol portion (5APs 1 ); (ii) a methyl group was inserted on C3 of the pyrazole scaffold (5APs 2 ); (iii) a more flexible alkyl chain was inserted on N1 position (5APs 3 ); (iv) the acylhydrazonic linker was moved from position 4 to position 3 of the pyrazole scaffold (5APs 4 ). All new derivatives 1-4 have been tested for radical scavenging (DPPH assay), anti-aggregating/antioxidant (in human platelets) and cell growth inhibitory activity (MTT assay) properties. In addition, in silico pharmacokinetics, drug-likeness properties, and toxicity have been calculated. 5APs 1 emerged to be promising anti-proliferative agents, able to suppress the growth of specific cancer cell lines. Furthermore, derivatives 3 remarkably inhibited ROS production in platelets and 5APs 4 showed interesting in vitro radical scavenging properties. Overall, the collected results further confirm the pharmaceutical potentials of this class of compounds and support future studies for the development of novel anti-proliferative and antioxidant agents.
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- 2024
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77. Insights into the Pharmacological Activity of the Imidazo-Pyrazole Scaffold.
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Spallarossa A, Rapetti F, Signorello MG, Rosano C, Iervasi E, Ponassi M, and Brullo C
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- Humans, Molecular Docking Simulation, Structure-Activity Relationship, Cell Line, Tumor, Pyrazoles pharmacology, Pyrazoles chemistry, Drug Screening Assays, Antitumor, Molecular Structure, Cell Proliferation, Tubulin metabolism, Antineoplastic Agents pharmacology, Antineoplastic Agents chemistry
- Abstract
In previous studies, we synthesized different imidazo-pyrazoles 1 and 2 with interesting anticancer, anti-angiogenic and anti-inflammatory activities. To further extend the structure-activity relationships of imidazo-pyrazole scaffold and to identify novel antiproliferative/anti-inflammatory agents potentially active with multi-target mechanisms, a library of compounds 3-5 has been designed and synthesized. The chemical modifications characterizing the novel derivatives include: i) decoration of the catechol ring with groups with different electronic, steric and lipophilic properties (compounds 3); ii) insertion of a methyl group on C-6 of imidazo-pyrazole scaffold (compounds 4); iii) shift of the acylhydrazonic substituent from position 7 to 6 of the imidazo-pyrazole substructure (compounds 5). All synthesized compounds were tested against a panel of cancer and normal cell lines. Derivatives 3 a, 3 e, 4 c, 5 g and 5 h showed IC
50 values in the low micromolar range against selected tumor cell lines and proved to have antioxidant properties, being able to inhibit ROS production in human platelet. In silico calculation predicted favourable drug-like and pharmacokinetic properties for the most promising compounds. Furthermore, molecular docking and molecular dynamic simulations suggested the ability of most active derivative 3 e to interact with colchicine binding site in the polymeric tubulin α/tubulin β/stathmin4 complex., (© 2023 The Authors. ChemMedChem published by Wiley-VCH GmbH.)- Published
- 2023
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78. Scouting Different Phosphodiesterase 4 Inhibitor Chemotypes in Silico To Guide the Design of Anti-inflammatory/Antioxidant Agents.
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Cichero E, Rapetti F, Lusardi M, Scarano N, Alfei S, Altieri P, Garibaldi S, Ameri P, Grazia Signorello M, and Brullo C
- Subjects
- Antioxidants pharmacology, Molecular Docking Simulation, Endothelial Cells, Cyclic Nucleotide Phosphodiesterases, Type 4 chemistry, Anti-Inflammatory Agents pharmacology, Anti-Inflammatory Agents chemistry, Catechols chemistry, Phosphodiesterase 4 Inhibitors pharmacology
- Abstract
During the last years, we developed a large library of new selective phosphodiesterase 4D inhibitors, maintaining the catechol portion of the well-known PDE4 inhibitor Rolipram, featuring different substitutions in place of the lactam group of this reference compound. Based on the X-ray analysis of PDE4 inhibitors (PDE4Is) previously synthesized by us and of naphthyridine- and naphthyridinone-containing derivatives exhibiting PDE4 inhibitory ability described in the literature, we designed and synthesized new compounds 1-3. All of them were screened in silico as putative PDE4Is, via molecular docking studies to exploit structural variation at the catechol group to gain further contacts especially with the flat aromatic residues (Phe506 and Phe538) of enzyme. Subsequent in silico prediction of ADMET properties and in vitro biological assays on platelets and endothelial cells are in good agreement with our previous data concerning the antioxidant/anti-inflammatory activity exhibited by our previous PDE4Is and similarly to other well-known PDE4Is., (© 2023 The Authors. ChemMedChem published by Wiley-VCH GmbH.)
- Published
- 2023
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79. Design, synthesis, biological evaluation and structural characterization of novel GEBR library PDE4D inhibitors.
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Brullo C, Rapetti F, Abbate S, Prosdocimi T, Torretta A, Semrau M, Massa M, Alfei S, Storici P, Parisini E, and Bruno O
- Subjects
- Binding Sites, Catalytic Domain, Crystallography, X-Ray, Cyclic AMP metabolism, Cyclic Nucleotide Phosphodiesterases, Type 4 chemistry, Cyclic Nucleotide Phosphodiesterases, Type 4 genetics, Humans, Molecular Docking Simulation, Phosphodiesterase 4 Inhibitors chemistry, Phosphodiesterase 4 Inhibitors metabolism, Protein Isoforms antagonists & inhibitors, Protein Isoforms metabolism, Recombinant Proteins biosynthesis, Recombinant Proteins chemistry, Recombinant Proteins isolation & purification, Small Molecule Libraries chemical synthesis, Small Molecule Libraries metabolism, Structure-Activity Relationship, Cyclic Nucleotide Phosphodiesterases, Type 4 metabolism, Drug Design, Phosphodiesterase 4 Inhibitors chemical synthesis, Small Molecule Libraries chemistry
- Abstract
Memory and cognitive functions depend on the cerebral levels of cyclic adenosine monophosphate (cAMP), which are regulated by the phosphodiesterase 4 (PDE4) family of enzymes. Selected rolipram-related PDE4 inhibitors, members of the GEBR library, have been shown to increase hippocampal cAMP levels, providing pro-cognitive benefits with a safe pharmacological profile. In a recent SAR investigation involving a subset of GEBR library compounds, we have demonstrated that, depending on length and flexibility, ligands can either adopt a twisted, an extended or a protruding conformation, the latter allowing the ligand to form stabilizing contacts with the regulatory domain of the enzyme. Here, based on those findings, we describe further chemical modifications of the protruding subset of GEBR library inhibitors and their effects on ligand conformation and potency. In particular, we demonstrate that the insertion of a methyl group in the flexible linker region connecting the catechol portion and the basic end of the molecules enhances the ability of the ligand to interact with both the catalytic and the regulatory domains of the enzyme., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)
- Published
- 2021
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80. Novel insights on the molecular mechanism of action of the anti-angiogenic pyrazolyl-urea GeGe-3 by functional proteomics.
- Author
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Morretta E, Belvedere R, Petrella A, Spallarossa A, Rapetti F, Bruno O, Brullo C, and Monti MC
- Subjects
- Angiogenesis Inhibitors metabolism, Angiogenesis Inhibitors pharmacology, Binding Sites, Calcium metabolism, Calreticulin chemistry, Calreticulin metabolism, Down-Regulation drug effects, Focal Adhesion Kinase 1 metabolism, Human Umbilical Vein Endothelial Cells, Humans, Ionomycin pharmacology, Molecular Docking Simulation, Proteome drug effects, Angiogenesis Inhibitors chemistry, Proteome metabolism, Proteomics methods, Pyrazoles chemistry, Urea chemistry
- Abstract
In recent years, 5-pyrazolyl-ureas have mostly been known for their attractive poly-pharmacological outline and, in particular, ethyl 1-(2-hydroxypentyl)-5-(3-(3-(trifluoromethyl) phenyl) ureido)-1H-pyrazole-4-carboxylate (named GeGe-3) has emerged as a capable anti-angiogenic compound. This paper examines its interactome by functional proteomics using a label-free mass spectrometry based platform, coupling Drug Affinity Responsive Target Stability and targeted Limited Proteolysis-Multiple Reaction Monitoring. Calreticulin has been recognized as the GeGe-3 principal target and this evidence has been supported by immunoblotting and in silico molecular docking. Furthermore, cell studies have shown that GeGe-3 lowers cell calcium mobilization, cytoskeleton organization and focal adhesion kinase expression, thus linking its biological potential to calreticulin binding and, ultimately, shedding light on the reasonable action mechanism of this molecule as an anti-angiogenic factor., (Copyright © 2021 Elsevier Inc. All rights reserved.)
- Published
- 2021
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81. New Series of Pyrazoles and Imidazo-Pyrazoles Targeting Different Cancer and Inflammation Pathways.
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Signorello MG, Rapetti F, Meta E, Sidibè A, Bruno O, and Brullo C
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- Anti-Inflammatory Agents chemistry, Anti-Inflammatory Agents pharmacology, Human Umbilical Vein Endothelial Cells, Humans, Phosphorylation drug effects, Platelet Aggregation drug effects, Reactive Oxygen Species metabolism, Small Molecule Libraries chemistry, Small Molecule Libraries pharmacology, Structure-Activity Relationship, Anti-Inflammatory Agents chemical synthesis, Imidazoles chemistry, Pyrazoles chemistry, Small Molecule Libraries chemical synthesis, p38 Mitogen-Activated Protein Kinases metabolism
- Abstract
(1) Background: different previously synthesized pyrazoles and imidazo-pyrazoles showed interesting anti-angiogenic action, being able to interfere with ERK1/2, AKT and p38MAPK phosphorylation in different manners and with different potency; (2) Methods: here, a new small compound library, endowed with the same differently decorated chemical scaffolds, has been synthetized to obtain new agents able to inhibit different pathways involved in inflammation, cancer and human platelet aggregation. (3) Results: most of the new synthesized derivatives resulted able to block ROS production, platelet aggregation and p38MAPK phosphorylation both in platelets and Human Umbilical Vein Endothelial cells (HUVEC). This paves the way for the development of new agents with anti-angiogenic activity.
- Published
- 2021
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82. Pyrazolyl-Ureas as Interesting Scaffold in Medicinal Chemistry.
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Brullo C, Rapetti F, and Bruno O
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- Chemistry Techniques, Synthetic, Humans, Pharmaceutical Preparations chemical synthesis, Structure-Activity Relationship, Chemistry, Pharmaceutical methods, Pharmaceutical Preparations chemistry, Pyrazoles chemistry, Urea chemistry
- Abstract
The pyrazole nucleus has long been known as a privileged scaffold in the synthesis of biologically active compounds. Within the numerous pyrazole derivatives developed as potential drugs, this review is focused on molecules characterized by a urea function directly linked to the pyrazole nucleus in a different position. In the last 20 years, the interest of numerous researchers has been especially attracted by pyrazolyl-ureas showing a wide spectrum of biological activities, ranging from the antipathogenic activities (bacteria, plasmodium, toxoplasma, and others) to the anticarcinogenic activities. In particular, in the anticancer field, pyrazolyl-ureas have been shown to interact at the intracellular level on many pathways, in particular on different kinases such as Src, p38-MAPK, TrKa, and others. In addition, some of them evidenced an antiangiogenic potential that deserves to be explored. This review therefore summarizes all these biological data (from 2000 to date), including patented compounds.
- Published
- 2020
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83. Discovery of New Antiproliferative Imidazopyrazole Acylhydrazones Able To Interact with Microtubule Systems.
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Brullo C, Rapetti F, Alfei S, Maric I, Rizzelli F, Mapelli M, Rosano C, Viale M, and Bruno O
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- Antineoplastic Agents chemical synthesis, Antineoplastic Agents chemistry, Apoptosis drug effects, Cell Proliferation drug effects, Dose-Response Relationship, Drug, Drug Screening Assays, Antitumor, Humans, Hydrazones chemical synthesis, Hydrazones chemistry, Molecular Structure, Pyrazoles chemical synthesis, Pyrazoles chemistry, Structure-Activity Relationship, Tumor Cells, Cultured, Antineoplastic Agents pharmacology, Drug Discovery, Hydrazones pharmacology, Microtubules drug effects, Pyrazoles pharmacology
- Abstract
Even though immunotherapy has radically changed the search for anticancer therapies, there are still many different pathways that are open to intervention with traditional small molecules. To expand our investigation in the anticancer field, we report here a new series of compounds in which our previous pyrazole and imidazopyrazole scaffolds are linked to a differently decorated phenyl ring through an acylhydrazone linker. Preliminary tests on the library were performed at the National Cancer Institute (USA) against the full NCI 60 cell panel. The best compounds among the imidazopyrazole series were then tested by immunofluorescence staining for their inhibition of cell proliferation, apoptosis induction, and their effect on the cell cycle and on microtubules. Two compounds, in particular 4-benzyloxy-3-methoxybenzyliden imidazopyrazole-7-carbohydrazide showed good growth inhibition, with IC
50 values in the low-micromolar range, and induced apoptosis. Both compounds altered the cell-cycle phases with the appearance of polyploid cells. Immunofluorescence analysis evidenced microtubules alterations; tubulin polymerization assays and docking studies suggested the tubulin system to be the possible, although not exclusive, target of the new acylhydrazone series reported here., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2020
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84. Insight into GEBR-32a: Chiral Resolution, Absolute Configuration and Enantiopreference in PDE4D Inhibition.
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Cavalloro V, Russo K, Vasile F, Pignataro L, Torretta A, Donini S, Semrau MS, Storici P, Rossi D, Rapetti F, Brullo C, Parisini E, Bruno O, and Collina S
- Subjects
- Humans, Nuclear Magnetic Resonance, Biomolecular, Cyclic Nucleotide Phosphodiesterases, Type 4 chemistry, Phosphodiesterase 4 Inhibitors chemistry
- Abstract
Alzheimer's disease is the most common type of dementia, affecting millions of people worldwide. One of its main consequences is memory loss, which is related to downstream effectors of cyclic adenosine monophosphate (cAMP). A well-established strategy to avoid cAMP degradation is the inhibition of phosphodiesterase (PDE). In recent years, GEBR-32a has been shown to possess selective inhibitory properties against PDE type 4 family members, resulting in an improvement in spatial memory processes without the typical side effects that are usually correlated with this mechanism of action. In this work, we performed the HPLC chiral resolution and absolute configuration assignment of GEBR-32a. We developed an efficient analytical and semipreparative chromatographic method exploiting an amylose-based stationary phase, we studied the chiroptical properties of both enantiomers and we assigned their absolute configuration by
1 H-NMR (nuclear magnetic resonance). Lastly, we measured the IC50 values of both enantiomers against both the PDE4D catalytic domain and the long PDE4D3 isoform. Results strongly support the notion that GEBR-32a inhibits the PDE4D enzyme by interacting with both the catalytic pocket and the regulatory domains., Competing Interests: O.B. and C.B. declare an Intellectual Property interest on GEBR-32a- Published
- 2020
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85. New Hybrid Pyrazole and Imidazopyrazole Antinflammatory Agents Able to Reduce ROS Production in Different Biological Targets.
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Brullo C, Massa M, Rapetti F, Alfei S, Bertolotto MB, Montecucco F, Signorello MG, and Bruno O
- Subjects
- Anti-Inflammatory Agents chemical synthesis, Anti-Inflammatory Agents chemistry, Blood Platelets drug effects, Blood Platelets metabolism, Cell Survival drug effects, Chemotaxis drug effects, Cyclic Nucleotide Phosphodiesterases, Type 4 chemistry, Cyclic Nucleotide Phosphodiesterases, Type 4 metabolism, Cyclic Nucleotide Phosphodiesterases, Type 4 pharmacology, Humans, Male, Neutrophils drug effects, Neutrophils metabolism, Oxidation-Reduction, Phosphodiesterase 4 Inhibitors chemical synthesis, Phosphodiesterase 4 Inhibitors pharmacology, Platelet Aggregation drug effects, Pyrazoles chemical synthesis, Pyrazoles chemistry, Structure-Activity Relationship, Anti-Inflammatory Agents pharmacology, Pyrazoles pharmacology, Reactive Oxygen Species metabolism
- Abstract
Several anti-inflammatory agents based on pyrazole and imidazopyrazole scaffolds and a large library of substituted catechol PDE4D inhibitors were reported by us in the recent past. To obtain new molecules potentially able to act on different targets involved in inflammation onset we designed and synthesized a series of hybrid compounds by linking pyrazole and imidazo-pyrazole scaffolds to differently decorated catechol moieties through an acylhydrazone chain. Some compounds showed antioxidant activity, inhibiting reactive oxygen species (ROS) elevation in neutrophils, and a good inhibition of phosphodiesterases type 4D and, particularly, type 4B, the isoform most involved in inflammation. In addition, most compounds inhibited ROS production also in platelets, confirming their ability to exert an antiinflammatory response by two independent mechanism. Structure-activity relationship (SAR) analyses evidenced that both heterocyclic scaffolds (pyrazole and imidazopyrazole) and the substituted catechol moiety were determinant for the pharmacodynamic properties, even if hybrid molecules bearing to the pyrazole series were more active than the imidazopyrazole ones. In addition, the pivotal role of the catechol substituents has been analyzed. In conclusion the hybridization approach gave a new serie of multitarget antiinflammatory compounds, characterized by a strong antioxidant activity in different biological targets., Competing Interests: The authors have declared that there is no conflict of interests.
- Published
- 2020
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86. Positive End-expiratory Pressure and Mechanical Power.
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Collino F, Rapetti F, Vasques F, Maiolo G, Tonetti T, Romitti F, Niewenhuys J, Behnemann T, Camporota L, Hahn G, Reupke V, Holke K, Herrmann P, Duscio E, Cipulli F, Moerer O, Marini JJ, Quintel M, and Gattinoni L
- Subjects
- Animals, Disease Models, Animal, Swine, Lung physiopathology, Positive-Pressure Respiration adverse effects, Positive-Pressure Respiration methods, Ventilator-Induced Lung Injury prevention & control
- Abstract
Background: Positive end-expiratory pressure is usually considered protective against ventilation-induced lung injury by reducing atelectrauma and improving lung homogeneity. However, positive end-expiratory pressure, together with tidal volume, gas flow, and respiratory rate, contributes to the mechanical power required to ventilate the lung. This study aimed at investigating the effects of increasing mechanical power by selectively modifying its positive end-expiratory pressure component., Methods: Thirty-six healthy piglets (23.3 ± 2.3 kg) were ventilated prone for 50 h at 30 breaths/min and with a tidal volume equal to functional residual capacity. Positive end-expiratory pressure levels (0, 4, 7, 11, 14, and 18 cm H2O) were applied to six groups of six animals. Respiratory, gas exchange, and hemodynamic variables were recorded every 6 h. Lung weight and wet-to-dry ratio were measured, and histologic samples were collected., Results: Lung mechanical power was similar at 0 (8.8 ± 3.8 J/min), 4 (8.9 ± 4.4 J/min), and 7 (9.6 ± 4.3 J/min) cm H2O positive end-expiratory pressure, and it linearly increased thereafter from 15.5 ± 3.6 J/min (positive end-expiratory pressure, 11 cm H2O) to 18.7 ± 6 J/min (positive end-expiratory pressure, 14 cm H2O) and 22 ± 6.1 J/min (positive end-expiratory pressure, 18 cm H2O). Lung elastances, vascular congestion, atelectasis, inflammation, and septal rupture decreased from zero end-expiratory pressure to 4 to 7 cm H2O (P < 0.0001) and increased progressively at higher positive end-expiratory pressure. At these higher positive end-expiratory pressure levels, striking hemodynamic impairment and death manifested (mortality 0% at positive end-expiratory pressure 0 to 11 cm H2O, 33% at 14 cm H2O, and 50% at 18 cm H2O positive end-expiratory pressure). From zero end-expiratory pressure to 18 cm H2O, mean pulmonary arterial pressure (from 19.7 ± 5.3 to 32.2 ± 9.2 mmHg), fluid administration (from 537 ± 403 to 2043 ± 930 ml), and noradrenaline infusion (0.04 ± 0.09 to 0.34 ± 0.31 μg · kg(-1) · min(-1)) progressively increased (P < 0.0001). Lung weight and lung wet-to-dry ratios were not significantly different across the groups. The lung mechanical power level that best discriminated between more versus less severe damage was 13 ± 1 J/min., Conclusions: Less than 7 cm H2O positive end-expiratory pressure reduced atelectrauma encountered at zero end-expiratory pressure. Above a defined power threshold, sustained positive end-expiratory pressure contributed to potentially lethal lung damage and hemodynamic impairment.
- Published
- 2019
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87. Extracorporeal CO2 Removal: The Minimally Invasive Approach, Theory, and Practice.
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Duscio E, Cipulli F, Vasques F, Collino F, Rapetti F, Romitti F, Behnemann T, Niewenhuys J, Tonetti T, Pasticci I, Vassalli F, Reupke V, Moerer O, Quintel M, and Gattinoni L
- Subjects
- Animals, Carbon Dioxide blood, Catheterization, Central Venous, Models, Animal, Respiratory Insufficiency therapy, Swine, Ventilator Weaning, Extracorporeal Membrane Oxygenation methods
- Abstract
Objectives: Minimally invasive extracorporeal CO2 removal is an accepted supportive treatment in chronic obstructive pulmonary disease patients. Conversely, the potential of such technique in treating acute respiratory distress syndrome patients remains to be investigated. The aim of this study was: 1) to quantify membrane lung CO2 removal (VCO2ML) under different conditions and 2) to quantify the natural lung CO2 removal (VCO2NL) and to what extent mechanical ventilation can be reduced while maintaining total expired CO2 (VCO2tot = VCO2ML + VCO2NL) and arterial PCO2 constant., Design: Experimental animal study., Setting: Department of Experimental Animal Medicine, University of Göttingen, Germany., Subjects: Eight healthy pigs (57.7 ± 5 kg)., Interventions: The animals were sedated, ventilated, and connected to the artificial lung system (surface 1.8 m, polymethylpentene membrane, filling volume 125 mL) through a 13F catheter. VCO2ML was measured under different combinations of inflow PCO2 (38.9 ± 3.3, 65 ± 5.7, and 89.9 ± 12.9 mm Hg), extracorporeal blood flow (100, 200, 300, and 400 mL/min), and gas flow (4, 6, and 12 L/min). At each setting, we measured VCO2ML, VCO2NL, lung mechanics, and blood gases., Measurements and Main Results: VCO2ML increased linearly with extracorporeal blood flow and inflow PCO2 but was not affected by gas flow. The outflow PCO2 was similar regardless of inflow PCO2 and extracorporeal blood flow, suggesting that VCO2ML was maximally exploited in each experimental condition. Mechanical ventilation could be reduced by up to 80-90% while maintaining a constant PaCO2., Conclusions: Minimally invasive extracorporeal CO2 removal removes a relevant amount of CO2 thus allowing mechanical ventilation to be significantly reduced depending on extracorporeal blood flow and inflow PCO2. Extracorporeal CO2 removal may provide the physiologic prerequisites for controlling ventilator-induced lung injury.
- Published
- 2019
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88. Reclassifying Acute Respiratory Distress Syndrome.
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Maiolo G, Collino F, Vasques F, Rapetti F, Tonetti T, Romitti F, Cressoni M, Chiumello D, Moerer O, Herrmann P, Friede T, Quintel M, and Gattinoni L
- Subjects
- Adult, Aged, Aged, 80 and over, Chile, Dyspnea diagnosis, Female, Germany, Humans, Italy, Male, Middle Aged, Respiratory Distress Syndrome diagnosis, Dyspnea therapy, Extracorporeal Membrane Oxygenation methods, Respiration, Artificial methods, Respiratory Distress Syndrome classification, Respiratory Distress Syndrome therapy
- Abstract
Rationale: The ratio of Pa
O to Fi2 O (P/F) defines acute respiratory distress syndrome (ARDS) severity and suggests appropriate therapies., Objectives: We investigated 1) whether a 150-mm-Hg P/F threshold within the range of moderate ARDS (100-200 mm Hg) would define two subgroups that were more homogeneous; and 2) which criteria led the clinicians to apply extracorporeal membrane oxygenation (ECMO) in severe ARDS., Methods: At the 150-mm-Hg P/F threshold, moderate patients were split into mild-moderate (n = 50) and moderate-severe (n = 55) groups. Patients with severe ARDS (Fi2 O not available in three patients) were split into higher (n = 63) and lower (n = 18) Fi2 O groups at an 80% Fi2 O threshold., Measurements and Main Results: Compared with mild-moderate ARDS, patients with moderate-severe ARDS had higher peak pressures, Pa2 CO , and pH. They also had heavier lungs, greater inhomogeneity, more noninflated tissue, and greater lung recruitability. Within 84 patients with severe ARDS (P/F < 100 mm Hg), 75% belonged to the higher Fi2 O subgroup. They differed from the patients with severe ARDS with lower Fi2 O only in Pa2 CO and lung weight. Forty-one of 46 patients treated with ECMO belonged to the higher Fi2 O group. Within this group, the patients receiving ECMO had higher Pa2 CO than the 22 non-ECMO patients. The inhomogeneity ratio, total lung weight, and noninflated tissue were also significantly higher., Conclusions: Using the 150-mm-Hg P/F threshold gave a more homogeneous distribution of patients with ARDS across the severity subgroups and identified two populations that differed in their anatomical and physiological characteristics. The patients treated with ECMO belonged to the severe ARDS group, and almost 90% of them belonged to the higher Fi2 O subgroup.2 - Published
- 2018
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89. Effects of regional perfusion block in healthy and injured lungs.
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Cambiaghi B, Vasques F, Mörer O, Ritter C, Mauri T, Kunze-Szikszay N, Holke K, Collino F, Maiolo G, Rapetti F, Schulze-Kalthoff E, Tonetti T, Hahn G, Quintel M, and Gattinoni L
- Abstract
Background: Severe hypoperfusion can cause lung damage. We studied the effects of regional perfusion block in normal lungs and in the lungs that had been conditioned by lavage with 500 ml saline and high V
T (20 ml kg-1 ) ventilation., Methods: Nineteen pigs (61.2 ± 2.5 kg) were randomized to five groups: controls (n = 3), the right lower lobe block alone (n = 3), lavage and high VT (n = 4), lung lavage, and high VT plus perfusion block of the right (n = 5) or left (n = 4) lower lobe. Gas exchange, respiratory mechanics, and hemodynamics were measured hourly. After an 8-h observation period, CT scans were obtained at 0 and 15 cmH2 O airway pressure., Results: Perfusion block did not damage healthy lungs. In conditioned lungs, the left perfusion block caused more edema in the contralateral lung (777 ± 62 g right lung vs 484 ± 204 g left; p < 0.05) than the right perfusion block did (581 ± 103 g right lung vs 484 ± 204 g left; p n.s.). The gas/tissue ratio, however, was similar (0.5 ± 0.3 and 0.8 ± 0.5; p n.s.). The lobes with perfusion block were not affected (gas/tissue ratio right 1.6 ± 0.9; left 1.7 ± 0.5, respectively). Pulmonary artery pressure, PaO2 /FiO2 , dead space, and lung mechanics were more markedly affected in animals with left perfusion block, while the gas/tissue ratios were similar in the non-occluded lobes., Conclusions: The right and left perfusion blocks caused the same "intensity" of edema in conditioned lungs. The total amount of edema in the two lungs differed because of differences in lung size. If capillary permeability is altered, increased blood flow may induce or increase edema.- Published
- 2017
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90. The future of mechanical ventilation: lessons from the present and the past.
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Gattinoni L, Marini JJ, Collino F, Maiolo G, Rapetti F, Tonetti T, Vasques F, and Quintel M
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- Barotrauma physiopathology, Barotrauma therapy, Extracorporeal Membrane Oxygenation methods, Extracorporeal Membrane Oxygenation trends, Humans, Respiratory Distress Syndrome physiopathology, Respiratory Distress Syndrome therapy, Respiratory Mechanics physiology, Tidal Volume physiology, Ventilator-Induced Lung Injury physiopathology, Ventilator-Induced Lung Injury therapy, Forecasting, Respiration, Artificial trends
- Abstract
The adverse effects of mechanical ventilation in acute respiratory distress syndrome (ARDS) arise from two main causes: unphysiological increases of transpulmonary pressure and unphysiological increases/decreases of pleural pressure during positive or negative pressure ventilation. The transpulmonary pressure-related side effects primarily account for ventilator-induced lung injury (VILI) while the pleural pressure-related side effects primarily account for hemodynamic alterations. The changes of transpulmonary pressure and pleural pressure resulting from a given applied driving pressure depend on the relative elastances of the lung and chest wall. The term 'volutrauma' should refer to excessive strain, while 'barotrauma' should refer to excessive stress. Strains exceeding 1.5, corresponding to a stress above ~20 cmH
2 O in humans, are severely damaging in experimental animals. Apart from high tidal volumes and high transpulmonary pressures, the respiratory rate and inspiratory flow may also play roles in the genesis of VILI. We do not know which fraction of mortality is attributable to VILI with ventilation comparable to that reported in recent clinical practice surveys (tidal volume ~7.5 ml/kg, positive end-expiratory pressure (PEEP) ~8 cmH2 O, rate ~20 bpm, associated mortality ~35%). Therefore, a more complete and individually personalized understanding of ARDS lung mechanics and its interaction with the ventilator is needed to improve future care. Knowledge of functional lung size would allow the quantitative estimation of strain. The determination of lung inhomogeneity/stress raisers would help assess local stresses; the measurement of lung recruitability would guide PEEP selection to optimize lung size and homogeneity. Finding a safety threshold for mechanical power, normalized to functional lung volume and tissue heterogeneity, may help precisely define the safety limits of ventilating the individual in question. When a mechanical ventilation set cannot be found to avoid an excessive risk of VILI, alternative methods (such as the artificial lung) should be considered.- Published
- 2017
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91. Positive end-expiratory pressure: how to set it at the individual level.
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Gattinoni L, Collino F, Maiolo G, Rapetti F, Romitti F, Tonetti T, Vasques F, and Quintel M
- Abstract
The positive end-expiratory pressure (PEEP), since its introduction in the treatment of acute respiratory failure, up to the 1980s was uniquely aimed to provide a viable oxygenation. Since the first application, a large debate about the criteria for selecting the PEEP levels arose within the scientific community. Lung mechanics, oxygen transport, venous admixture thresholds were all proposed, leading to PEEP recommendations from 5 up to 25 cmH
2 O. Throughout this period, the main concern was the hemodynamics. This paradigm changed during the 1980s after the wide acceptance of atelectrauma as one of the leading causes of ventilator induced lung injury. Accordingly, the PEEP aim shifted from oxygenation to lung protection. In this framework, the prevention of lung opening and closing became an almost unquestioned dogma. Consequently, as PEEP keeps open the pulmonary units opened during the previous inspiratory phase, new methods were designed to identify the 'optimal' PEEP during the expiratory phase. The open lung approach requires that every collapsed unit potentially openable is opened and maintained open. The methods to assess the recruitment are based on imaging (computed tomography, electric impedance tomography, ultrasound) or mechanically-driven gas exchange modifications. All the latest assume that whatever change in respiratory system compliance is due to changes in lung compliance, which in turn is uniquely function of the recruitment. Comparative studies, however, showed that the only possible approach to measure the amount of collapsed tissue regaining inflation is the CT scan. In fact, all the other methods estimate as recruitment the gas entry in pulmonary units already open at lower PEEP, but increasing their compliance at higher PEEP. Since higher PEEP is usually more indicated (also for oxygenation) when the recruitability is higher, as occurs with increasing severity, a meaningful PEEP selection requires the assessment of recruitment. The Berlin definition may help in this assessment., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.- Published
- 2017
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92. Driving pressure and mechanical power: new targets for VILI prevention.
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Tonetti T, Vasques F, Rapetti F, Maiolo G, Collino F, Romitti F, Camporota L, Cressoni M, Cadringher P, Quintel M, and Gattinoni L
- Abstract
Several factors have been recognized as possible triggers of ventilator-induced lung injury (VILI). The first is pressure (thus the 'barotrauma'), then the volume (hence the 'volutrauma'), finally the cyclic opening-closing of the lung units ('atelectrauma'). Less attention has been paid to the respiratory rate and the flow, although both theoretical considerations and experimental evidence attribute them a significant role in the generation of VILI. The initial injury to the lung parenchyma is necessarily mechanical and it could manifest as an unphysiological distortion of the extracellular matrix and/or as micro-fractures in the hyaluronan, likely the most fragile polymer embedded in the matrix. The order of magnitude of the energy required to break a molecular bond between the hyaluronan and the associated protein is 1.12×10
-16 Joules (J), 70-90% higher than the average energy delivered by a single breath of 1L assuming a lung elastance of 10 cmH2 O/L (0.5 J). With a normal statistical distribution of the bond strength some polymers will be exposed each cycle to an energy large enough to rupture. Both the extracellular matrix distortion and the polymer fractures lead to inflammatory increase of capillary permeability with edema if a pulmonary blood flow is sufficient. The mediation analysis of higher vs. lower tidal volume and PEEP studies suggests that the driving pressure, more than tidal volume, is the best predictor of VILI, as inferred by increased mortality. This is not surprising, as both tidal volume and respiratory system elastance (resulting in driving pressure) may independently contribute to the mortality. For the same elastance driving pressure is a predictor similar to plateau pressure or tidal volume. Driving pressure is one of the components of the mechanical power, which also includes respiratory rate, flow and PEEP. Finding the threshold for mechanical power would greatly simplify assessment and prevention of VILI., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.- Published
- 2017
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93. Volutrauma, Atelectrauma, and Mechanical Power.
- Author
-
Tonetti T, Cressoni M, Collino F, Maiolo G, Rapetti F, Quintel M, and Gattinoni L
- Subjects
- Humans, Respiration, Artificial, Respiratory Distress Syndrome, Ventilator-Induced Lung Injury
- Published
- 2017
- Full Text
- View/download PDF
Catalog
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