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We present an improved measurement of the carbon-nitrogen-oxygen (CNO) solar neutrino interaction rate at Earth obtained with the complete Borexino Phase-III dataset. The measured rate, R_{CNO}=6.7_{-0.8}^{+2.0} counts/(day×100 tonnes), allows us to exclude the absence of the CNO signal with about 7σ C.L. The correspondent CNO neutrino flux is 6.6_{-0.9}^{+2.0}×10^{8} cm^{-2} s^{-1}, taking into account the neutrino flavor conversion. We use the new CNO measurement to evaluate the C and N abundances in the Sun with respect to the H abundance for the first time with solar neutrinos. Our result of N_{CN}=(5.78_{-1.00}^{+1.86})×10^{-4} displays a â¼2σ tension with the "low-metallicity" spectroscopic photospheric measurements. Furthermore, our result used together with the ^{7}Be and ^{8}B solar neutrino fluxes, also measured by Borexino, permits us to disfavor at 3.1σ C.L. the "low-metallicity" standard solar model B16-AGSS09met as an alternative to the "high-metallicity" standard solar model B16-GS98.
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We report the measurement of sub-MeV solar neutrinos through the use of their associated Cherenkov radiation, performed with the Borexino detector at the Laboratori Nazionali del Gran Sasso. The measurement is achieved using a novel technique that correlates individual photon hits of events to the known position of the Sun. In an energy window between 0.54 to 0.74 MeV, selected using the dominant scintillation light, we have measured 10 887_{-2103}^{+2386}(stat)±947(syst) (68% confidence interval) solar neutrinos out of 19 904 total events. This corresponds to a ^{7}Be neutrino interaction rate of 51.6_{-12.5}^{+13.9} counts/(day·100 ton), which is in agreement with the standard solar model predictions and the previous spectroscopic results of Borexino. The no-neutrino hypothesis can be excluded with >5σ confidence level. For the first time, we have demonstrated the possibility of utilizing the directional Cherenkov information for sub-MeV solar neutrinos, in a large-scale, high light yield liquid scintillator detector. This measurement provides an experimental proof of principle for future hybrid event reconstruction using both Cherenkov and scintillation signatures simultaneously.
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OBJECTIVES: The aim of the study was to investigate whether the rs35761398 variants of the cannabinoid receptor 2 (CB2) gene may influence the acquisition of HIV infection and the clinical presentation of HIV/hepatitis C virus (HCV) coinfection. METHODS: We compared 166 HIV/HCV-coinfected patients with 186 HCV-monoinfected patients, all with biopsy-proven chronic hepatitis (using the Ishak scoring system), naïve for anti-HCV treatment and tested for the CB2 rs35761398 polymorphism (using the TaqMan assay). RESULTS: The HIV/HCV-coinfected patients were more frequently male (P < 0.002), were younger (P < 0.001), and had lower median BMI (P < 0.001) and HCV RNA (P < 0.05) and higher median aspartate aminotransferase (AST; P < 0.001), alanine aminotransferase (ALT; P < 0.001) and gamma glutamyl transferase (GGT; P < 0.001) levels than the HCV-monoinfected patients. The CB2 RR variant predominated in HIV/HCV-coinfected patients (45.8% vs. 31.2% in HCV-monoinfected patients; P < 0.001) and the CB2 QR variant in HCV-monoinfected patients (57.5% vs. 38.6% in HIV/HCV-coinfected patients; P < 0.00001), and the CB2 QQ variant was equally distributed. Focusing on patients with the CB2 QQ variant, the 26 HIV/HCV-coinfected patients, compared with the 21 HCV-monoinfected patients, showed less severe liver necroinflammation [lower histological activity index (HAI)] (P < 0.05). Of the patients with the CB2 RR variant, the 76 HIV/HCV-coinfected patients, compared with the 58 HCV-monoinfected patients, were more frequently male (P < 0.05), were younger (P < 0.001), and had a lower median body mass index (BMI; P < 0.001), a higher median AST level (P < 0.001), a higher mean HAI score (P < 0.05) and a higher rate of cases with severe steatosis (P = 0.05). In an analysis of variance (anova) of HCV/HIV-coinfected and HCV-monoinfected patient data, those with the CB2 RR variant (P = 0.003) and of male sex (P = 0.002) were more prevalent in the HCV/HIV-coinfected group. CONCLUSIONS: There is the suggestion of a positive effect of the CB2 RR variant on HIV acquisition and/or spread, which is in accordance with previous in vitro observations.
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Infecciones por VIH/epidemiología , Hepatitis C/genética , Polimorfismo de Nucleótido Simple , Receptor Cannabinoide CB2/genética , Adulto , Coinfección/epidemiología , Estudios Transversales , Femenino , Predisposición Genética a la Enfermedad , Infecciones por VIH/genética , Infecciones por VIH/metabolismo , Hepatitis C/epidemiología , Hepatitis C/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Minorías Sexuales y de Género/clasificaciónRESUMEN
Borexino is a liquid scintillation detector located deep underground at the Laboratori Nazionali del Gran Sasso (LNGS, Italy). Thanks to the unmatched radio purity of the scintillator, and to the well understood detector response at low energy, a new limit on the stability of the electron for decay into a neutrino and a single monoenergetic photon was obtained. This new bound, τ≥6.6×10^{28} yr at 90% C.L., is 2 orders of magnitude better than the previous limit.
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OBJECTIVES: To investigate whether the functional variant Q63R of the cannabinoid 2 (CB2) receptor is associated with susceptibility to oligo/poly-articular juvenile idiopathic arthritis (JIA) and with its clinical features. METHOD: A total of 171 Italian children with oligoarticular/rheumatoid factor negative poly-articular JIA and 600 healthy controls were enrolled in the study and genotyped. RESULTS: A significant difference in genotype distribution of the CB2 Q63R variant (CNR2 rs35761398) between oligo/poly-articular JIA patients and controls was found (p = 0.001). The R63 variant was associated with increased rates of relapse (p = 0.0001). CONCLUSIONS: This study indicates that the CB2 receptor contributes to susceptibility to oligo/polyarticular JIA and to the severity of its clinical course.
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Artritis Juvenil/genética , Artritis/genética , Variación Genética/genética , Receptor Cannabinoide CB2/genética , Artritis/etnología , Artritis Juvenil/etnología , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Predisposición Genética a la Enfermedad/etnología , Predisposición Genética a la Enfermedad/genética , Genotipo , Humanos , Italia , Masculino , Índice de Severidad de la EnfermedadRESUMEN
The purinergic system is highly involved in the regulation of microglial physiological processes. In addition to the accepted roles for the P2 X4,7 and P2 Y12 receptors activated by adenosine triphosphate (ATP) and adenosine diphosphate, respectively, recent evidence suggests a role for the adenosine A2A receptor in microglial cytoskeletal rearrangements. However, the expression and function of adenosine A1 receptor (A1AR) in microglia is still unclear. Several reports have demonstrated possible expression of A1AR in microglia, but a new study has refuted such evidence. In this study, we investigated the presence and function of A1AR in microglia using biomolecular techniques, live microscopy, live calcium imaging, and in vivo electrophysiological approaches. The aim of this study was to clarify the expression of A1AR in microglia and to highlight its possible roles. We found that microglia express A1AR and that it is highly upregulated upon ATP treatment. Moreover, we observed that selective stimulation of A1AR inhibits the morphological activation of microglia, possibly by suppressing the Ca(2+) influx induced by ATP treatment. Finally, we recorded the spontaneous and evoked activity of spinal nociceptive-specific neuron before and after application of resting or ATP-treated microglia, with or without preincubation with a selective A1AR agonist. We found that the microglial cells, pretreated with the A1AR agonist, exhibit lower capability to facilitate the nociceptive neurons, as compared with the cells treated with ATP alone.
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Microglía/fisiología , Receptor de Adenosina A1/metabolismo , Potenciales de Acción/efectos de los fármacos , Adenosina Trifosfato/farmacología , Animales , Animales Recién Nacidos , Calcio/metabolismo , Células Cultivadas , Lipopolisacáridos/farmacología , Ratones , Microglía/efectos de los fármacos , Agonistas del Receptor Purinérgico P1/farmacología , Antagonistas de Receptores Purinérgicos P1/farmacología , ARN Mensajero/metabolismo , ARN Interferente Pequeño/metabolismo , Receptor de Adenosina A1/genética , Médula Espinal/citología , Médula Espinal/metabolismoRESUMEN
We observed, for the first time, solar neutrinos in the 1.0-1.5 MeV energy range. We determined the rate of pep solar neutrino interactions in Borexino to be 3.1±0.6{stat}±0.3{syst} counts/(day·100 ton). Assuming the pep neutrino flux predicted by the standard solar model, we obtained a constraint on the CNO solar neutrino interaction rate of <7.9 counts/(day·100 ton) (95% C.L.). The absence of the solar neutrino signal is disfavored at 99.97% C.L., while the absence of the pep signal is disfavored at 98% C.L. The necessary sensitivity was achieved by adopting data analysis techniques for the rejection of cosmogenic {11}C, the dominant background in the 1-2 MeV region. Assuming the Mikheyev-Smirnov-Wolfenstein large mixing angle solution to solar neutrino oscillations, these values correspond to solar neutrino fluxes of (1.6±0.3)×10{8} cm{-2} s^{-1} and <7.7×10{8} cm{-2} s{-1} (95% C.L.), respectively, in agreement with both the high and low metallicity standard solar models. These results represent the first direct evidence of the pep neutrino signal and the strongest constraint of the CNO solar neutrino flux to date.
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The rate of neutrino-electron elastic scattering interactions from 862 keV (7)Be solar neutrinos in Borexino is determined to be 46.0±1.5(stat)(-1.6)(+1.5)(syst) counts/(day·100 ton). This corresponds to a ν(e)-equivalent (7)Be solar neutrino flux of (3.10±0.15)×10(9) cm(-2) s(-1) and, under the assumption of ν(e) transition to other active neutrino flavours, yields an electron neutrino survival probability of 0.51±0.07 at 862 keV. The no flavor change hypothesis is ruled out at 5.0 σ. A global solar neutrino analysis with free fluxes determines Φ(pp)=6.06(-0.06)(+0.02)×10(10) cm(-2) s(-1) and Φ(CNO)<1.3×10(9) cm(-2) s(-1) (95% C.L.). These results significantly improve the precision with which the Mikheyev-Smirnov-Wolfenstein large mixing angle neutrino oscillation model is experimentally tested at low energy.
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The Deception Island, located in Maritime Antarctica, is a volcanic island with geothermal activity and one of the most visited by tourists. However, the extent of the anthropogenic impact remains largely unknown and the factors shaping the resistance/tolerance mechanisms in the microbiomes from Whalers Bay ecosystems have never been investigated. In this context, this study aimed to reveal the resistome profiles of Whalers Bay sediments and correlate them with environmental factors. Samples were collected at four sites during the summer 2014/2015 along a transect of 27.5â¯m in the Whalers Bay sediments. DNA isolated from sediment samples was sequenced using the Illumina HiSeq platform. Bioinformatic analyses allowed the assembly of contigs and scaffolds, prediction of ORFs, and taxonomic and functional annotation using NCBI RefSeq database and KEGG orthology, respectively. Microorganisms belonging to the genera Psychrobacter, Flavobacterium and Polaromonas were shown to dominate all sites, representing 60% of taxonomic annotation. Arsenic (As), copper (Cu) and iron (Fe) were the most abundant metal resistance/tolerance types found in the microbiomes. Beta-lactam was the most common class related to antibiotics resistance/tolerance, corroborating with previous environmental resistome studies. The acridine class was the most abundant amongst the biocide resistance/tolerances, related to antiseptic compounds. Results gathered in this study reveal a repertoire of resistance/tolerance classes to antibiotics and biocides unusually found in Antarctica. However, given the volcanic nature (heavy metals-rich region) of Deception Island soils, this putative impact must be viewed with caution.
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Monitoreo del Ambiente , Regiones Antárticas , Arsénico/análisis , Ecosistema , Sedimentos Geológicos/análisis , Islas , Metales Pesados/análisisRESUMEN
The endogenous fatty acid amide palmitoylethanolamide (PEA) has been shown to exert anti-inflammatory actions mainly through inhibition of the release of pro-inflammatory molecules from mast cells, monocytes and macrophages. Indirect activation of the endocannabinoid (eCB) system is among the several mechanisms of action that have been proposed to underlie the different effects of PEA in vivo. In this study, we used cultured rat microglia and human macrophages to evaluate whether PEA affects eCB signaling. PEA was found to increase CB2 mRNA and protein expression through peroxisome proliferator-activated receptor-α (PPAR-α) activation. This novel gene regulation mechanism was demonstrated through: (i) pharmacological PPAR-α manipulation, (ii) PPAR-α mRNA silencing, (iii) chromatin immunoprecipitation. Moreover, exposure to PEA induced morphological changes associated with a reactive microglial phenotype, including increased phagocytosis and migratory activity. Our findings suggest indirect regulation of microglial CB2R expression as a new possible mechanism underlying the effects of PEA. PEA can be explored as a useful tool for preventing/treating the symptoms associated with neuroinflammation in CNS disorders.
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Movimiento Celular/efectos de los fármacos , Etanolaminas/farmacología , Macrófagos/efectos de los fármacos , Microglía/efectos de los fármacos , Ácidos Palmíticos/farmacología , Fagocitosis/efectos de los fármacos , Receptor Cannabinoide CB2/metabolismo , Amidas , Animales , Células HEK293 , Humanos , Macrófagos/metabolismo , Microglía/metabolismo , PPAR alfa/metabolismo , ARN Mensajero/metabolismo , RatasRESUMEN
Rizatriptan represents a major advance in the treatment of migraine attack: inhibition of peripheral trigeminal nerve and constriction of intracranial extracerebral blood vessels have been proposed as its main antimigraine mechanisms of action. Although many studies may suggest that rizatriptan causes highly selective vasoconstriction within intracranial extracerebral vessels (i.e., meningeal arteries), no literature data are available to date on possible cerebral hemodynamic changes in humans after treatment with rizatriptan. The aim of this study was to evaluate the effect of rizatriptan on cerebral blood flow velocity performing transcranial Doppler during spontaneous attacks of migraine without aura. Fourteen patients suffering from migraine without aura were monitored to evaluate mean flow velocity changes on both middle cerebral arteries during migraine attack 30 min before and 120 min after oral administration of rizatriptan 10mg. Monitoring was repeated for 30 min during the pain-free period. All patients turned out to be drug responders and no significant mean flow velocity changes were observed between the pain-free period and pre-treatment phase; besides no significant difference in mean flow velocity value have been detected between the periods after the drug administration during the attack versus both pre-treatment period and pain-free phase. These findings indicate that the antimigraine action of rizatriptan is not associated with clear intracranial cerebral hemodynamic changes and may support its cerebrovascular safety.
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Corteza Cerebral/efectos de los fármacos , Trastornos Migrañosos/sangre , Flujo Sanguíneo Regional/efectos de los fármacos , Agonistas de Receptores de Serotonina/administración & dosificación , Triazoles/administración & dosificación , Adulto , Corteza Cerebral/fisiología , Femenino , Lateralidad Funcional , Humanos , Flujometría por Láser-Doppler/métodos , Masculino , Persona de Mediana Edad , Arteria Cerebral Media/efectos de los fármacos , Arteria Cerebral Media/fisiopatología , Trastornos Migrañosos/tratamiento farmacológico , Factores de Tiempo , TriptaminasRESUMEN
The impact of the cannabinoid receptor 2 (CB2) rs35761398 polymorphism on chronic hepatitis B (CHB) was evaluated in 106 consecutive biopsy-proven CHB patients naive for antiviral therapy. A histological activity index (HAI) > 8 (Ishak scoring) was more frequent in patients with CB2-63 RR than in those with CB2-63 QR or QQ (37% vs. 16.7%, p < 0.05). The logistic regression analysis identified CB2-63 RR (p < 0.05) and a fibrosis score >3 (p < 0.005) as independently associated with an HAI >8. The observation that the CB2-63 RR variant is an independent predictor of extensive necroinflammation opens up new prospects in the study of CHB.
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Hepatitis B Crónica/genética , Hepatitis B Crónica/patología , Cirrosis Hepática/genética , Cirrosis Hepática/patología , Polimorfismo Genético , Receptor Cannabinoide CB2/genética , Índice de Severidad de la Enfermedad , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Because alteration of oscillatory potentials of the electroretinogram has been described in diabetic patients without signs of diabetic retinopathy as an early marker of changes in microcirculation, we studied the behavior of these potentials in patients with early-onset hypertension. Electroretinograms were recorded in 24 subjects with essential hypertension (blood pressure > 140/90 mm Hg) and in 9 age-matched normotensive control subjects (blood pressure < 140/90 mm Hg). Diabetes and ocular diseases were considered exclusion criteria. Sitting blood pressure was measured by a single investigator with a mercury sphygmomanometer after each subject had been at rest for 10 minutes. Funduscopic changes in all subjects did not exceed stage I World Health Organization classification. The oscillatory index was calculated by adding waves O1, O2, and O3 within the b wave of the electroretinogram. Statistical analysis was performed with Student's t test for paired and unpaired data and linear regression. The oscillatory index was significantly reduced in hypertensive patients compared with normotensive subjects. An inverse relationship was observed when systolic and diastolic blood pressures were plotted against the oscillatory index. In conclusion, our data demonstrate that the electrical activity of the retina is altered early in the course of hypertension and that the influence of systolic pressure on the oscillatory index is greater than that of diastolic pressure.
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Electrorretinografía , Hipertensión/fisiopatología , Adulto , Presión Sanguínea , Femenino , Humanos , Masculino , Persona de Mediana Edad , Oscilometría , Valores de Referencia , Análisis de RegresiónRESUMEN
Benign familial neonatal convulsions (BFNC) is a rare autosomal inherited epilepsy. We studied the KCNQ2 coding region in a large, four-generation, Italian family with BFNC. A missense mutation C686T predicting the change of one of the innermost arginine (R214W) of the key functional voltage sensor (S4 helix), has been found in all affected members. This substitution probably reduces the movement of the voltage sensor that precedes channel opening during voltage-dependent activation. Several mutations affecting the trans-membrane domain and the pore region of the K+ channels belonging to the KQT-like family have been described in some human diseases associated with altered regulation of cellular excitability (ie BFNC, some LQT syndromes and DFNA2). R214W represents the first mutation involving the region of the voltage sensor.
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Epilepsia Benigna Neonatal/genética , Mutación Missense , Canales de Potasio/genética , Secuencia de Aminoácidos , Análisis Mutacional de ADN , Femenino , Humanos , Lactante , Canal de Potasio KCNQ2 , Masculino , Datos de Secuencia Molecular , Linaje , Canales de Potasio con Entrada de Voltaje , Homología de Secuencia de AminoácidoRESUMEN
We investigated the molecular basis of hyperekplexia (STHE), an inherited neurological disorder characterised by neonatal hypertonia and an exaggerated startle response, in a kindred and identified a novel missense mutation in the pore-lining M2 domain of the alpha1 subunit of the glycine receptor (GLRA1). Sequencing analysis of all exons of the GLRA1 gene revealed a G1158A base transition in affected, heterozygous patients. The base transition results in a valine to methionine substitution at codon 260 in the middle of the M2 transmembrane domain. The location within the M2 domain suggests for this substitution a likely role in altering ion channel properties.
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Enfermedades del Sistema Nervioso/genética , Receptores de Glicina/genética , Secuencia de Aminoácidos , Secuencia de Bases , Sitios de Unión/genética , ADN/química , ADN/genética , Análisis Mutacional de ADN , Salud de la Familia , Femenino , Humanos , Masculino , Proteínas de la Membrana/genética , Datos de Secuencia Molecular , Mutación Missense , Linaje , Reflejo de Sobresalto/genética , Homología de Secuencia de AminoácidoRESUMEN
Selective serotonin reuptake inhibitors have been used in the treatment of depression in patients with PD. Conflicting data as to whether selective serotonin reuptake inhibitors worsen parkinsonian motor symptomatology have been reported. In this study, the additional 6 months therapy with paroxetine 20 mg/d in a group of depressed patients with PD did not modify parkinsonian motor function (Unified Parkinson's Disease Rating Scale scores); however, in one patient, fully reversible worsening of tremor was observed. Depression, as evaluated by Beck Depression Inventory and Hamilton Depression Rating Scale, improved from baseline to final visit (p < 0.05 by analysis of variance).
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Trastorno Depresivo/tratamiento farmacológico , Enfermedad de Parkinson/tratamiento farmacológico , Paroxetina/uso terapéutico , Desempeño Psicomotor/efectos de los fármacos , Anciano , Análisis de Varianza , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: Rats fed a high-fructose diet develop hyperinsulinaemia, hypertriglyceridaemia, hypertension, renal changes similar to those in diabetic rats and left ventricular hypertrophy with deposition of collagen. Bosentan is an antagonist of endothelin receptors. Other authors have demonstrated that bosentan is effective in preventing the increase in blood pressure induced by a high-fructose diet but, until now, the effect of the drug on the target organs has not been investigated. OBJECTIVE: To evaluate whether bosentan is effective, not only in reducing blood pressure, but also in limiting the renal and cardiac changes induced by a high-fructose diet METHODS: Forty Wistar-Kyoto (WKY) male rats were divided into four groups: groups 1 and 2 received a high-fructose diet, groups 3 and 4 received a standard diet for 1 month. Thereafter, the following treatments were administered: group 1, high-fructose diet plus bosentan 100 mg/kg per day; group 2, high-fructose diet plus placebo; group 3, standard diet plus bosentan 100 mg/kg per day; group 4, standard diet plus placebo. After a further 1 month, all animals were killed. A morphometric analysis was performed by examining 100 glomeruli for each animal. Renal deposits of collagen and fibronectin and cardiac deposits of collagen III were measured by means of immunochemistry. RESULTS: By the end of the study, bosentan had completely reversed the increase in blood pressure induced by a high-fructose diet, without modifying the blood pressure in normotensive rats. Moreover, bosentan reduced glomerular hypertrophy and deposits of collagen and fibronectin in the kidney and cardiac deposits of collagen III. CONCLUSIONS: The results of this study demonstrate that bosentan not only normalizes blood pressure, but also protects target organs in rats receiving a high-fructose diet.
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Antihipertensivos/farmacología , Presión Sanguínea/efectos de los fármacos , Carbohidratos de la Dieta/farmacología , Fructosa/farmacología , Sulfonamidas/farmacología , Animales , Peso Corporal/efectos de los fármacos , Bosentán , Relación Dosis-Respuesta a Droga , Inmunohistoquímica , Riñón/metabolismo , Glomérulos Renales/efectos de los fármacos , Glomérulos Renales/patología , Masculino , Miocardio/metabolismo , Ratas , Ratas Endogámicas WKYRESUMEN
BACKGROUND: Losartan is a new angiotensin II type 1 (AT1) receptor antagonist and an antihypertensive drug. Nitric oxide is a vasodilating agent and endothelins are powerful vasoconstrictors, both synthesized by and released from endothelial cells. Angiotensin II promotes the release of endothelins in cultured cells and this effect is prevented by losartan. Nitric oxide is also synthesized in the macula densa; therefore this substance may affect the regulation of renin excretion. OBJECTIVE: The aim of the present study was to evaluate the effects of losartan on blood pressure, endothelin-like immunoreactivity and nitric oxide in normotensive rats. MATERIALS AND METHODS: Male Wistar-Kyoto rats were divided into two groups. One group (n = 10) was treated with losartan at 10 mg/kg once a day by gavage for 4 weeks and a placebo group (n = 10) was given the same volume of water once a day by gavage. Blood pressure was measured weekly with a tail cuff and 24-h urine was collected at the beginning and at the end of the study. After 4 weeks all rats were killed and blood samples taken. Endothelin-like immunoreactivity was determined in plasma and urine using a 125I endothelin radioimmunuoassy kit. The stable metabolic products of nitric oxide, NO2- and NO3-, were measured in urine by the brucine method. RESULTS: After 4 weeks blood pressure was significantly lower in the losartan group (131 +/- 4 versus 118 +/- 6 mmHg, P = 0.001). Plasma endothelin-like immunoreactivity was similar in both groups while 24-h urinary endothelin-like immunoreactivity was significantly increased in the losartan group (29 +/- 25, 32 +/- 21, 43 +/- 19, 72 +/- 30 pg/24 h; F = 0.0003). NO2- and NO3- were unchanged in both groups. CONCLUSIONS: Our data show that chronic AT1 receptor blockade does not modify plasma endothelin-like immunoreactivity but increases urinary endothelin-like immunoreactivity. The significance of this finding remains obscure. It may represent a compensatory mechanism against the sustained vasodilation caused by losartan. Nitric oxide does not seem to affect the antihypertensive effect of losartan, since the urinary excretion of nitric oxide metabolites was unchanged.
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Antagonistas de Receptores de Angiotensina , Antihipertensivos/farmacología , Compuestos de Bifenilo/farmacología , Presión Sanguínea/efectos de los fármacos , Endotelinas/metabolismo , Imidazoles/farmacología , Óxido Nítrico/metabolismo , Tetrazoles/farmacología , Animales , Presión Sanguínea/fisiología , Endotelinas/efectos de los fármacos , Losartán , Masculino , Ratas , Ratas Endogámicas WKYRESUMEN
OBJECTIVE: Normotensive rats fed a high fructose diet (HFD) develop hypertriglyceridemia, hyperinsulinemia and hypertension. The glomerular changes observed in the kidneys of these animals are similar to those observed in diabetic rats. The aim of this study was to evaluate whether lacidipine could be effective not only in preventing, but also in inducing the regression of hypertension, and renal and cardiac damage in rats fed HFD. METHODS: Thirty male Wistar-Kyoto (WKY) rats received HFD for 1 month; thereafter, five rats were sacrificed (Group 1) and the other 25 rats were divided into three groups: Group 2 (five rats) received HFD plus placebo, Group 3 (10 rats) HFD plus lacidipine 3 mg/kg per day, and Group 4 (10 rats) HFD plus hydralazine 10 mg/kg per day. At the end of the second month all animals were sacrificed. Kidneys and hearts were immediately removed. Renal deposits of collagen I, collagen IV, fibronectin and cardiac deposits of collagen III were assessed by means of immunohistochemistry. RESULTS: In the rats receiving HFD plus placebo, blood pressure was increased after the first and the second month of diet. This increase was reversed by lacidipine and hydralazine but, although both drugs normalized blood pressure, only lacidipine was effective in reducing renal and cardiac damage. CONCLUSIONS: These data suggest that lacidipine is effective in reversing hypertension and reducing target organ damage induced by HFD. Moreover, this protective effect on target organs appears to be not simply a consequence of blood pressure reduction, but seems to be connected to the type of hypotensive drug administered.
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Antihipertensivos/farmacología , Presión Sanguínea/efectos de los fármacos , Dihidropiridinas/farmacología , Fructosa/efectos adversos , Hipertensión/inducido químicamente , Hipertensión/tratamiento farmacológico , Glomérulos Renales/efectos de los fármacos , Glomérulos Renales/fisiopatología , Animales , Colágeno/metabolismo , Dieta , Dihidropiridinas/uso terapéutico , Fibronectinas , Fructosa/administración & dosificación , Glomérulos Renales/metabolismo , Masculino , Miocardio/metabolismo , Ratas , Ratas Endogámicas WKYRESUMEN
Endothelins (ET) are recently discovered vasoconstrictor agents released from endothelial cells and have been the object of intense investigation by researchers. Many of the factors that seem to influence the release of ET are modified by prolonged exercise. The purpose of this study was to investigate the effect of physical exercise on ET plasma concentrations and the effect of alpha- and beta-blockade on ET concentrations at rest and during exercise. Fifteen young volunteers (age 20-35 years) performed an exercise test on a bicycle ergometer. The starting workload of 50 W was increased by 30 W every 3 min until maximal heart rate was achieved; after a 2 min recovery period at 50 W the test continued for 15 min at 60% maximal work load. Blood samples were taken for ET determination before and after the test. After 1 week, the test was repeated. In the 2 days before either the first or the second test, each volunteer randomly received carvedilol (C) (25 mg), an alpha 1-adrenoceptor and beta-adrenoceptor blocker. There was no significant difference in ET concentrations after exercise with or without C administration (1.24 +/- 0.66, 1.42 +/- 0.83, 1.66 +/- 1.15, 1.61 +/- 0.87 pg/mL), showing that prolonged aerobic exercise does not affect plasma ET levels. Moreover, in our healthy young volunteers, blockade of alpha- and beta-adrenoceptors had no effect on ET levels at rest and after exercise.