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1.
Cancer Radiother ; 23(6-7): 658-661, 2019 Oct.
Artigo em Francês | MEDLINE | ID: mdl-31471252

RESUMO

Stereotactic radiotherapy represents a fundamental change in the practice of radiotherapy of lung cancers. Despite the great heterogeneity of sites, techniques, and doses, most studies found a high local control rate, around 70 to 90% at 2 years, and reduced toxicity, around 5% of grade 3 at 2 years. Stereotactic radiotherapy can be realized either by a dedicated accelerator (CyberKnife®) or by a conventional accelerator associated with specific systems. The two modalities deliver a very precise irradiation whose very good results published to date are similar. Some technical characteristics specific to each type of linear accelerator could guide the choice according to the target volume treated.


Assuntos
Neoplasias Pulmonares/radioterapia , Aceleradores de Partículas , Radiocirurgia/instrumentação , Humanos , Movimentos dos Órgãos , Órgãos em Risco/efeitos da radiação , Radiocirurgia/métodos , Respiração , Resultado do Tratamento
2.
Cancer Radiother ; 23(6-7): 496-499, 2019 Oct.
Artigo em Francês | MEDLINE | ID: mdl-31471251

RESUMO

Stereotactic radiotherapy of oligometastases, mono- or hypofractionated, represents a fundamental change in the practice of the specialty as it was developed for a century. Despite the great heterogeneity of sites, techniques, and doses, most studies found a high local control rate, around 70 to 90% at 2 years, and reduced toxicity, around 5% of grade 3 at 2 years. Four main phase II and III trials are underway in France. Future research concerns the association of stereotactic radiotherapy with immunotherapy or different conventional chemotherapy protocols, the identification of the best clinical presentations, and optimization of fractionation and biological dose for poor prognosis localizations.


Assuntos
Ensaios Clínicos Fase II como Assunto , Ensaios Clínicos Fase III como Assunto , Neoplasias/radioterapia , Radiocirurgia/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto , Anticorpos Monoclonais/uso terapêutico , Antineoplásicos Imunológicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Ósseas/radioterapia , Neoplasias Ósseas/secundário , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/radioterapia , Terapia Combinada/métodos , Previsões , França , Humanos , Imunoterapia , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/radioterapia , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/radioterapia , Masculino , Metástase Neoplásica , Neoplasias/patologia , Neoplasias/terapia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/radioterapia , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/radioterapia
3.
Cancer Radiother ; 23(6-7): 732-736, 2019 Oct.
Artigo em Francês | MEDLINE | ID: mdl-31400955

RESUMO

When localized, the reference treatment of urothelial, muscle-invasive bladder tumours relies on radical cystectomy with reconstruction by enterocystoplasty if possible or Bricker bypass. Trimodal therapy combining transurethral resection of the tumour followed by concomitant chemotherapy may be considered as a therapeutic alternative to radical cystectomy in well-selected patients with unifocal tumours, stage T2, non-diverticular location, without in situ carcinoma or hydronephrosis and with macroscopically complete transurethral resection. The functional prognosis of the bladder and quality of life should be discussed with the patient as well as the need for salvage surgery for persistent tumour at a 45-Gy dose level, the latter being a highly unfavourable prognosis factor. On the other hand, this trimodal treatment is the reference in case of surgical contraindication. This article details the methods and results of the main series available in the literature in terms of local control, survival, bladder preservation rates and complications, as well as study prospects.


Assuntos
Quimiorradioterapia/métodos , Tratamentos com Preservação do Órgão/métodos , Neoplasias da Bexiga Urinária/terapia , Bexiga Urinária , Antineoplásicos/uso terapêutico , Terapia Combinada/métodos , Cistectomia/métodos , Humanos , Qualidade de Vida , Bexiga Urinária/cirurgia , Neoplasias da Bexiga Urinária/patologia
4.
Vascul Pharmacol ; 115: 33-45, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30790705

RESUMO

Perinatal sodium overload induces endothelial dysfunction in adult offspring, but the underlying mechanisms are not fully known. The involvement of tissue renin-angiotensin system on high sodium-programmed endothelial dysfunction was examined. Acetylcholine and angiotensin I and II responses were analyzed in aorta and mesenteric resistance arteries from 24-week-old male offspring of normal-salt (O-NS, 1.3% NaCl) and high-salt (O-HS, 8% NaCl) fed dams. COX-2 expression, O2- production and angiotensin converting enzyme (ACE) activity were determined. A separated O-HS was treated with losartan (15 mg kg-1/day) for eight weeks. Compared to O-NS, O-HS were normotensive. Acetylcholine-induced relaxation was impaired in O-HS arteries, which was improved by tempol, apocynin or indomethacin. The angiotensin I-induced contraction was greater in O-HS arteries, whereas the angiotensin II responses were unchanged. ACE activity, O2- production and COX-2 expression were increased in O-HS arteries. In this group, the increased O2- production was inhibited by apocynin or losartan. Chronic losartan decreased COX-2 expression and restored the endothelium-dependent vasodilation in O-HS. Our findings reiterate that perinatal sodium overload programs endothelial dysfunction in adult offspring through a blood pressure-independent mechanism. Our results also suggest that vascular angiotensin II is the main mediator of high sodium-programmed endothelial dysfunction, promoting COX-2 expression and oxidative stress.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Aorta Torácica/fisiopatologia , Endotélio Vascular/fisiopatologia , Fenômenos Fisiológicos da Nutrição Materna , Artérias Mesentéricas/fisiopatologia , Efeitos Tardios da Exposição Pré-Natal , Sistema Renina-Angiotensina , Cloreto de Sódio na Dieta/efeitos adversos , Fatores Etários , Angiotensina I/farmacologia , Angiotensina II/farmacologia , Animais , Aorta Torácica/efeitos dos fármacos , Aorta Torácica/metabolismo , Ciclo-Oxigenase 2/metabolismo , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Feminino , Masculino , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Peptidil Dipeptidase A/metabolismo , Gravidez , Ratos Wistar , Sistema Renina-Angiotensina/efeitos dos fármacos , Superóxidos/metabolismo , Vasoconstrição/efeitos dos fármacos , Vasoconstritores/farmacologia , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia
5.
Biochim Biophys Acta Mol Basis Dis ; 1864(12): 3577-3587, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30254014

RESUMO

We investigated whether hypertension induced by maternal lipopolysaccharide (LPS) administration during gestation is linked to peripheral vascular and renal hemodynamic regulation, through angiotensin II → NADPH-oxidase signalling, and whether these changes are directly linked to intrauterine oxidative stress. Female Wistar rats were submitted to LPS, in the absence or presence of α-tocopherol during pregnancy. Malondialdehyde in placenta and in livers from dams and foetuses was enhanced by LPS. Tail-cuff systolic blood pressure (tcSBP) was elevated in the 16-week-old LPS offspring. Renal malondialdeyde and protein expression of NADPH oxidase isoform 2 were elevated in these animals at 20 weeks of age. Maternal α-tocopherol treatment prevented the elevation in malondialdehyde induced by LPS on placenta and livers from dams and foetuses, as well as prevented the elevation in tcSBP and the elevation in renal malondialdehyde in adult life. LPS offspring presented impairment of endothelium-dependent relaxation in aorta and mesenteric rings, which was blunted by angiotensin type 1 receptor (AT1R) blockade and NADPH oxidase inhibition. At age of 32 weeks, renal hemodynamic parameters were unchanged in anaesthetised LPS offspring, but angiotensin II infusion led to an increased glomerular filtration rate paralleled by filtration fraction elevation. The renal haemodynamic changes provoked by angiotensin II was prevented by early treatment with α-tocopherol and by late treatment with NADPH oxidase inhibitor. These results point to oxidative stress as a mediator of offspring hypertension programmed by maternal inflammation and to the angiotensin II → NADPH oxidase signalling pathway as accountable for vascular and renal dysfunctions that starts and maintains hypertension.

6.
Eur J Pharmacol ; 822: 59-68, 2018 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-29355555

RESUMO

Ageing impairs endothelial function, which is considered a hallmark of the development of cardiovascular diseases in elderly. Cilostazol, a phosphodiesterase-3 inhibitor, has antiplatelet, antithrombotic and protective effects on endothelial cells. Here, we hypothesized that cilostazol could improve endothelial function in mesenteric resistance arteries (MRA) from old rats. Using eight-week cilostazol-treated (100mg/kg/day) or untreated 72-week-old Wistar rats, we evaluate the relaxation to acetylcholine, sodium nitroprusside (SNP), forskolin and isoproterenol and the noradrenaline-induced contraction in MRA. Superoxide anion and nitric oxide (NO) was measured by dihydroethidium- and diaminofluorescein-2-emitted fluorescence, respectively. Normotensive old rats had impaired acetylcholine-induced NO- and EDHF-mediated relaxation and increased noradrenaline vasoconstriction than young rats. This age-associated endothelial dysfunction was restored by cilostazol treatment. Relaxation to SNP, forskolin or isoproterenol remained unmodified by cilostazol. Diaminofluorescein-2-emitted fluorescence was increased while dihydroethidium-emitted was decreased by cilostazol, indicating increased NO and reduced superoxide generation, respectively. Cilostazol improves endothelial function in old MRA without affecting blood pressure. This protective effect of cilostazol could be attributed to reduced oxidative stress, increased NO bioavailability and EDHF-type relaxation. Although these results are preliminary, we believe that should stimulate further interest in cilostazol as an alternative for the treatment of age-related vascular disorders.


Assuntos
Envelhecimento/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 3/metabolismo , Endotélio Vascular/efeitos dos fármacos , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/fisiologia , Inibidores da Fosfodiesterase 3/farmacologia , Tetrazóis/farmacologia , Animais , Pressão Arterial/efeitos dos fármacos , Cilostazol , Endotélio Vascular/metabolismo , Masculino , Artérias Mesentéricas/citologia , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Wistar , Superóxidos/metabolismo , Vasoconstrição/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos
7.
Chem Commun (Camb) ; 53(64): 8960-8963, 2017 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-28639656

RESUMO

Herein we present organic mixed-valence compounds with an innovative H-shape design, where four redox centres are bridged "vertically" via a dibenzofulvene backbone and "horizontally" via a bis-(dibenzofulvene)-thiophene bridge. These compounds are easily oxidized to stable highly charged radical species which show intense intervalence charge transfer transitions in the near infrared region. Interestingly, depending on the position of the arylamine substituents on the bridge, both vertical and horizontal electron transfer pathways can be optically induced.

8.
PLoS One ; 11(6): e0156793, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27272874

RESUMO

INTRODUCTION: We analysed possible time-dependent changes in nitrergic perivascular innervation function from diabetic rats and mechanisms implicated. MATERIALS AND METHODS: In endothelium-denuded mesenteric arteries from control and four- (4W) and eight-week (8W) streptozotocin-induced diabetic rats the vasoconstriction to EFS (electrical field stimulation) was analysed before and after preincubation with L-NAME. Neuronal NO release was analysed in the absence and presence of L-arginine, tetrahydrobiopterine (BH4) and L-arginine plus BH4. Superoxide anion (O2-), peroxynitrite (ONOO-) and superoxide dismutase (SOD) activity were measured. Expressions of Cu-Zn SOD, nNOS, p-nNOS Ser1417, p-nNOS Ser847, and Arginase (Arg) I and II were analysed. RESULTS: EFS response was enhanced at 4W, and to a lesser extent at 8W. L-NAME increased EFS response in control rats and at 8W, but not at 4W. NO release was decreased at 4W and restored at 8W. L-arginine or BH4 increased NO release at 4W, but not 8W. SOD activity and O2- generation were increased at both 4W and 8W. ONOO- decreased at 4W while increased at 8W. Cu-Zn SOD, nNOS and p-NOS Ser1417 expressions remained unmodified at 4W and 8W, whereas p-nNOS Ser847 was increased at 4W. ArgI was overexpressed at 4W, remaining unmodified at 8W. ArgII expression was similar in all groups. CONCLUSIONS: Our results show a time-dependent effect of diabetes on neuronal NO release. At 4W, diabetes induced increased O2- generation, nNOS uncoupling and overexpression of ArgI and p-nNOS Ser847, resulting in decreased NO release. At 8W, NO release was restored, involving normalisation of ArgI and p-nNOS Ser847 expressions.


Assuntos
Diabetes Mellitus Experimental/metabolismo , Artérias Mesentéricas/efeitos dos fármacos , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico/metabolismo , Vasoconstrição/efeitos dos fármacos , Animais , Estimulação Elétrica , Masculino , Artérias Mesentéricas/metabolismo , Ácido Peroxinitroso/metabolismo , Ratos , Estreptozocina , Superóxido Dismutase/metabolismo , Superóxidos/metabolismo , Fatores de Tempo
9.
PLoS One ; 9(7): e100356, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24992476

RESUMO

BACKGROUND AND PURPOSE: Tranilast, in addition to its capacity to inhibit mast cell degranulation, has other biological effects, including inhibition of reactive oxygen species, cytokines, leukotrienes and prostaglandin release. In the current study, we analyzed whether tranilast could alter endothelial function in rat mesenteric resistance arteries (MRA). EXPERIMENTAL APPROACH: Acetylcholine-induced relaxation was analyzed in MRA (untreated and 1-hour tranilast treatment) from 6 month-old Wistar rats. To assess the possible participation of endothelial nitric oxide or prostanoids, acetylcholine-induced relaxation was analyzed in the presence of L-NAME or indomethacin. The participation of endothelium-derived hyperpolarizing factor (EDHF) in acetylcholine-induced response was analyzed by preincubation with TRAM-34 plus apamin or by precontraction with a high K+ solution. Nitric oxide (NO) and superoxide anion levels were measured, as well as vasomotor responses to NO donor DEA-NO and to large conductance calcium-activated potassium channel opener NS1619. KEY RESULTS: Acetylcholine-induced relaxation was greater in tranilast-incubated MRA. Acetylcholine-induced vasodilation was decreased by L-NAME in a similar manner in both experimental groups. Indomethacin did not modify vasodilation. Preincubation with a high K+ solution or TRAM-34 plus apamin reduced the vasodilation to ACh more markedly in tranilast-incubated segments. NO and superoxide anion production, and vasodilator responses to DEA-NO or NS1619 remained unmodified in the presence of tranilast. CONCLUSIONS AND IMPLICATIONS: Tranilast increased the endothelium-dependent relaxation to acetylcholine in rat MRA. This effect is independent of the nitric oxide and cyclooxygenase pathways but involves EDHF, and is mediated by an increased role of small conductance calcium-activated K+ channels.


Assuntos
Acetilcolina/farmacologia , Fatores Biológicos/fisiologia , Artérias Mesentéricas/efeitos dos fármacos , Vasodilatadores/farmacologia , ortoaminobenzoatos/farmacologia , Animais , Benzimidazóis/farmacologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/patologia , Hidrazinas/farmacologia , Indometacina/farmacologia , Masculino , Mastócitos/efeitos dos fármacos , Mastócitos/patologia , Artérias Mesentéricas/patologia , NG-Nitroarginina Metil Éster/farmacologia , Óxido Nítrico/metabolismo , Ratos , Ratos Wistar , Superóxidos/metabolismo
10.
J Chem Theory Comput ; 10(8): 3151-62, 2014 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-26588286

RESUMO

We performed a benchmark study on a series of dihydrogen bond complexes and constructed a set of reference bond distances and interaction energies. The test set was employed to assess the performance of several wave function correlated and density functional theory methods. We found that second-order correlation methods describe relatively well the dihydrogen complexes. However, for high accuracy inclusion of triple contributions is important. On the other hand, none of the considered density functional methods can simultaneously yield accurate bond lengths and interaction energies. However, we found that improved results can be obtained by the inclusion of nonlocal exchange contributions.

11.
PLoS One ; 8(8): e73232, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23977380

RESUMO

OBJECTIVES: We analyzed whether mast cell stabilization by either ketotifen or tranilast could alter either sympathetic or nitrergic innervation function in rat mesenteric arteries. METHODS: Electrical field stimulation (EFS)-induced contraction was analyzed in mesenteric segments from 6-month-old Wistar rats in three experimental groups: control, 3-hour ketotifen incubated (0.1 αmol/L), and 3-hour tranilast incubated (0.1 mmol/L). To assess the possible participation of nitrergic or sympathetic innervation, EFS contraction was analyzed in the presence of non-selective nitric oxide synthase (NOS) inhibitor L-NAME (0.1 mmol/L), α-adrenergic receptor antagonist phentolamine (0.1 µmol/L), or the neurotoxin 6-hydroxydopamine (6-OHDA, 1.46 mmol/L). Nitric oxide (NO) and superoxide anion (O2.(-) levels were measured, as were vasomotor responses to noradrenaline (NA) and to NO donor DEA-NO, in the presence and absence of 0.1 mmol/L tempol. Phosphorylated neuronal NOS (P-nNOS) expression was also analyzed. RESULTS: EFS-induced contraction was increased by ketotifen and decreased by tranilast. L-NAME increased the vasoconstrictor response to EFS only in control segments. The vasodilator response to DEA-NO was higher in ketotifen- and tranilast-incubated segments, while tempol increased vasodilator response to DEA-NO only in control segments. Both NO and O2(-) release, and P-nNOS expression were diminished by ketotifen and by tranilast treatment. The decrease in EFS-induced contraction produced by phentolamine was lower in tranilast-incubated segments. NA vasomotor response was decreased only by tranilast. The remnant vasoconstriction observed in control and ketotifen-incubated segments was abolished by 6-OHDA. CONCLUSION: While both ketotifen and tranilast diminish nitrergic innervation function, only tranilast diminishes sympathetic innnervation function, thus they alter the vasoconstrictor response to EFS in opposing manners.


Assuntos
Cetotifeno/farmacologia , Mastócitos/fisiologia , Artérias Mesentéricas/fisiologia , Vasoconstrição/efeitos dos fármacos , Vasoconstritores/farmacologia , ortoaminobenzoatos/farmacologia , Acetilcolina/farmacologia , Animais , Estimulação Elétrica , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/fisiologia , Liberação de Histamina/efeitos dos fármacos , Técnicas In Vitro , Masculino , Mastócitos/efeitos dos fármacos , Artérias Mesentéricas/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios Nitrérgicos/efeitos dos fármacos , Neurônios Nitrérgicos/fisiologia , Cloreto de Potássio/farmacologia , Ratos Wistar , Coloração e Rotulagem , Superóxidos/metabolismo , Cloreto de Tolônio/metabolismo , Vasodilatadores/farmacologia , Sistema Vasomotor/efeitos dos fármacos
12.
J Chem Phys ; 138(12): 124112, 2013 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-23556714

RESUMO

We apply the frozen density embedding method, using a full relaxation of embedded densities through a freeze-and-thaw procedure, to study the electronic structure of several benchmark ground-state charge-transfer complexes, in order to assess the merits and limitations of the approach for this class of systems. The calculations are performed using both semilocal and hybrid exchange-correlation (XC) functionals. The results show that embedding calculations using semilocal XC functionals yield rather large deviations with respect to the corresponding supermolecular calculations. Due to a large error cancellation effect, however, they can often provide a relatively good description of the electronic structure of charge-transfer complexes, in contrast to supermolecular calculations performed at the same level of theory. On the contrary, when hybrid XC functionals are employed, both embedding and supermolecular calculations agree very well with each other and with the reference benchmark results. In conclusion, for the study of ground-state charge-transfer complexes via embedding calculations hybrid XC functionals are the method of choice due to their higher reliability and superior performance.


Assuntos
Teoria Quântica
13.
J Chem Theory Comput ; 9(5): 2256-63, 2013 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-26583719

RESUMO

We construct a meta-generalized-gradient approximation which properly balances the nonlocality contributions to the exchange and correlation at the semilocal level. This nonempirical functional shows good accuracy for a broad palette of properties (thermochemistry, structural properties) and systems (molecules, metal clusters, surfaces, and bulk solids). The accuracy for several well-known problems in electronic structure calculations, such as the bending potential of the silver trimer and the dimensional crossover of anionic gold clusters, is also demonstrated. The inclusion of empirical dispersion corrections is finally discussed and analyzed.

14.
PLoS One ; 7(11): e50593, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23209788

RESUMO

This study analyzed the effect of in utero exposure to maternal diabetes on contraction to noradrenaline in mesenteric resistance arteries (MRA) from adult offspring, focusing on the role of cyclooxygenase (COX)-derived prostanoids. Diabetes in the maternal rat was induced by a single injection of streptozotocin (50 mg/kg body weight) on day 7 of pregnancy. Contraction to noradrenaline was analyzed in isolated MRA from offspring of diabetic (O-DR) and non-diabetic (O-CR) rats at 3, 6 and 12 months of age. Release of thromboxane A(2) (TxA(2)) and prostaglandins E(2) (PGE(2)) and F(2α) (PGF(2α)), was measured by specific enzyme immunoassay kits. O-DR developed hypertension from 6 months of age compared with O-CR. Arteries from O-DR were hyperactive to noradrenaline only at 6 and 12 months of age. Endothelial removal abolished this hyperreactivity to noradrenaline between O-CR and O-DR. Preincubation with either the COX-1/2 (indomethacin) or COX-2 inhibitor (NS-398) decreased noradrenaline contraction only in 6- and 12-month-old O-DR, while it remained unmodified by COX-1 inhibitor SC-560. In vessels from 6-month-old O-DR, a similar reduction in the contraction to noradrenaline produced by NS-398 was observed when TP and EP receptors were blocked (SQ29548+AH6809). In 12-month-old O-DR, this effect was only achieved when TP, EP and FP were blocked (SQ29548+AH6809+AL8810). Noradrenaline-stimulated TxB(2) and PGE(2) release was higher in 6- and 12-month-old O-DR, whereas PGF(2α) was increased only in 12-month-old O-DR. Our results demonstrated that in utero exposure to maternal hyperglycaemia in rats increases the participation of COX-2-derived prostanoids on contraction to noradrenaline, which might help to explain the greater response to this agonist in MRA from 6- and 12-month-old offspring. As increased contractile response in resistance vessels may contribute to hypertension, our results suggest a role for these COX-2-derived prostanoids in elevating vascular resistance and blood pressure in offspring of diabetic rats.


Assuntos
Ciclo-Oxigenase 2/metabolismo , Diabetes Mellitus Experimental/metabolismo , Artérias Mesentéricas/efeitos dos fármacos , Artérias Mesentéricas/metabolismo , Norepinefrina/farmacologia , Prostaglandinas/metabolismo , Animais , Células Cultivadas , Dinoprosta/análogos & derivados , Dinoprosta/farmacologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Feminino , Técnicas Imunoenzimáticas , Indometacina/farmacologia , Masculino , Nitrobenzenos/farmacologia , Gravidez , Prostaglandinas E/metabolismo , Prostaglandinas F/metabolismo , Ratos , Sulfonamidas/farmacologia , Tromboxano A2/metabolismo , Xantonas/farmacologia
15.
J Chem Phys ; 137(13): 134702, 2012 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-23039605

RESUMO

We present an extension of the charge-dipole model for the description of periodic systems. This periodic charge-dipole electrostatic model (PCDEM) allows one to describe the linear response of periodic structures in terms of charge- and dipole-type gaussian basis functions. The long-range electrostatic interaction is efficiently described by means of the continuous fast multipole method. As a first application, the PCDEM method is applied to describe the polarizability of silver slabs. We find that for a correct description of the polarizability of the slabs both charges and dipoles are required. However a continuum set of parametrizations, i.e., different values of the width of charge- and dipole-type gaussians, leads to an equivalent and accurate description of the slabs polarizability but a completely unphysical description of induced charge-density inside the slab. We introduced the integral squared density measure which allows one to obtain a unique parametrization which accurately describes both the polarizability and the induced density profile inside the slab. Finally the limits of the electrostatic approximations are also pointed out.


Assuntos
Teoria Quântica , Prata/química , Eletricidade Estática
16.
J Chem Phys ; 137(1): 014102, 2012 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-22779632

RESUMO

We analyze the accuracy of the frozen density embedding (FDE) method, with hybrid and orbital-dependent exchange-correlation functionals, for the calculation of the total interaction energies of weakly interacting systems. Our investigation is motivated by the fact that these approaches require, in addition to the non-additive kinetic energy approximation, also approximate non-additive exact-exchange energies. Despite this further approximation, we find that the hybrid/orbital-dependent FDE approaches can reproduce the total energies with the same accuracy (about 1 mHa) as the one of conventional semi-local functionals. In many cases, thanks to error cancellation effects, hybrid/orbital-dependent approaches yield even the smallest error. A detailed energy-decomposition investigation is presented. Finally, the Becke-exchange functional is found to reproduce accurately the non-additive exact-exchange energies also for non-equilibrium geometries. These performances are rationalized in terms of a reduced-gradient decomposition of the non-additive exchange energy.


Assuntos
Teoria Quântica , Cinética , Termodinâmica
17.
Phys Rev Lett ; 106(18): 186406, 2011 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-21635112

RESUMO

We use the asymptotic expansions of the semiclassical neutral atom as a reference system in density functional theory to construct accurate generalized gradient approximations (GGAs) for the exchange-correlation and kinetic energies without any empiricism. These asymptotic functionals are among the most accurate GGAs for molecular systems, perform well for solid state, and overcome current GGA state of the art in frozen density embedding calculations. Our results also provide evidence for the conjointness conjecture between exchange and kinetic energies of atomic systems.

18.
J Chem Phys ; 134(19): 194112, 2011 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-21599049

RESUMO

We compare the performance of different exchange-correlation functionals, based on the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation, for the structural and electronic properties of gold nanostructures. In particular we consider PBEsol (constructed to correctly describe solid-state systems) and PBEint [Phys. Rev. B 82, 113104 (2010)] which was recently introduced for hybrid interfaces and preserves the correct second-order gradient expansion of exchange energy (as in PBEsol) providing as well a significant nonlocality for higher density variation (as in PBE). We find that the PBEint functional gives a well balanced description of atomization energies, structural properties, energy differences between isomers, and bulk properties. Results indicate that PBEint is expected to be the most accurate functional for medium and large size gold clusters of different shapes.


Assuntos
Algoritmos , Química Física/métodos , Ouro/química , Modelos Químicos , Nanoestruturas/química , Simulação por Computador , Propriedades de Superfície , Termodinâmica
19.
Eur J Pharmacol ; 654(3): 280-8, 2011 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-21262224

RESUMO

This study analyzed the effect of aldosterone (0.05mg/kg per day, 3 weeks) on vasoconstriction induced by noradrenaline in mesenteric resistance arteries from WKY rats and SHR. Contraction to noradrenaline was measured in mesenteric resistance arteries from untreated and aldosterone-treatedrats from both strains. Participation of nitric oxide (NO), superoxide anions, thromboxane A(2) (TxA(2)) and prostacyclin in this response was determined. 6-keto-prostaglandin (PG)F1alpha and thromboxane B(2) (TxB(2)) releases were determined by enzyme immunoassay. NO and superoxide anion release were also determined by fluorescence and chemiluminiscence, respectively. Aldosterone did not modify noradrenaline-induced contraction in either strain. In mesenteric resistance arteries from both aldosterone-treated groups, endothelium removal or preincubation with NO synthesis inhibitor L-NAME increased the noradrenaline-induced contraction, while incubation with the superoxide anion scavenger tempol decreased it. Preincubation with either the COX-1/2 or COX-2 inhibitor (indomethacin and NS-398, respectively) decreased the noradrenaline contraction in aldosterone-treated animals, while this response was not modified by COX-1 inhibitor SC-560. TxA(2) synthesis inhibitor (furegrelate), or TxA2 receptor antagonist (SQ 29 548) also decreased the noradrenaline contraction in aldosterone-treated animals. In untreated SHR, but not WKY rats, this response was increased by L-NAME, and reduced by tempol, indomethacin, NS-398 or SQ 29 548. Aldosterone treatment did not modify NO or TxB(2) release, but it did increase superoxide anion and 6-keto-PGF(1alpha) release in mesenteric resistance arteries from both strains. In conclusion, chronic aldosterone treatment reduces smooth muscle contraction to alpha-adrenergic stimuli, producing a new balance in the release of endothelium-derived prostanoids and NO.


Assuntos
Aldosterona/farmacologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Hipertensão/fisiopatologia , Artérias Mesentéricas/efeitos dos fármacos , Norepinefrina/farmacologia , Vasoconstrição/efeitos dos fármacos , Aldosterona/sangue , Animais , Pressão Sanguínea/efeitos dos fármacos , Colágeno Tipo I/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Hidrocortisona/sangue , Hipertensão/sangue , Hipertensão/metabolismo , Hipertensão/patologia , Técnicas In Vitro , Masculino , Artérias Mesentéricas/metabolismo , Artérias Mesentéricas/fisiologia , Artérias Mesentéricas/fisiopatologia , Óxido Nítrico/metabolismo , Norepinefrina/sangue , Cloreto de Potássio/farmacologia , Prostaglandinas/biossíntese , Ratos , Ratos Endogâmicos WKY , Superóxidos/metabolismo
20.
J Chem Theory Comput ; 7(11): 3548-59, 2011 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-26598253

RESUMO

We assess the performance of the whole class of functionals defined by the Perdew-Burke-Ernzerhof (PBE) exchange-correlation enhancement factor, by performing a two-dimensional scan of the µ and κ parameters (keeping ß fixed by the recovery of the local density approximation linear response). We consider molecular (atomization energies, bond lengths, and vibrational frequencies), intermolecular (hydrogen-bond and dipole interactions), and solid-state (lattice constant and cohesive energies) properties. We find, for the energetical properties, a whole family of functionals (with µ and κ interrelated) giving very similar results and the best accuracy. Overall, we find that the original PBE and the recently proposed APBE functional [Phys. Rev. Lett.2011, 106, 186406], based on the asymptotic expansion of the semiclassical neutral atom, give the highest global accuracy, with a definite superior performance of the latter for all of the molecular properties.

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