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1.
Nat Commun ; 12(1): 4356, 2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34272371

RESUMO

Thermoelectric effects have been applied to power generators and temperature sensors that convert waste heat into electricity. The effects, however, have been limited to electrons to occur, and inevitably disappear at low temperatures due to electronic entropy quenching. Here, we report thermoelectric generation caused by nuclear spins in a solid: nuclear-spin Seebeck effect. The sample is a magnetically ordered material MnCO3 having a large nuclear spin (I = 5/2) of 55Mn nuclei and strong hyperfine coupling, with a Pt contact. In the system, we observe low-temperature thermoelectric signals down to 100 mK due to nuclear-spin excitation. Our theoretical calculation in which interfacial Korringa process is taken into consideration quantitatively reproduces the results. The nuclear thermoelectric effect demonstrated here offers a way for exploring thermoelectric science and technologies at ultralow temperatures.

2.
Radiat Oncol ; 15(1): 121, 2020 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-32448224

RESUMO

PURPOSE: Patients with left-sided breast cancer frequently receive deep inspiration breath-hold (DIBH) radiotherapy to reduce the risk of cardiac side effects. The aim of the present study was to analyze intra-breath-hold stability and inter-fraction breath-hold reproducibility in clinical practice. MATERIAL AND METHODS: Overall, we analyzed 103 patients receiving left-sided breast cancer radiotherapy using a surface-guided DIBH technique. During each treatment session the vertical motion of the patient was continuously measured by a surface guided radiation therapy (SGRT) system and automated gating control (beam on/off) was performed using an audio-visual patient feedback system. Dose delivery was automatically triggered when the tracking point was within a predefined gating window. Intra-breath-hold stability and inter-fraction reproducibility across all fractions of the entire treatment course were analyzed per patient. RESULTS: In the present series, 6013 breath-holds during beam-on time were analyzed. The mean amplitude of the gating window from the baseline breathing curve (maximum expiration during free breathing) was 15.8 mm (95%-confidence interval: [8.5-30.6] mm) and had a width of 3.5 mm (95%-CI: [2-4.3] mm). As a measure of intra-breath-hold stability, the median standard deviation of the breath-hold level during DIBH was 0.3 mm (95%-CI: [0.1-0.9] mm). Similarly, the median absolute intra-breath-hold linear amplitude deviation was 0.4 mm (95%-CI: [0.01-2.1] mm). Reproducibility testing showed good inter-fractional reliability, as the maximum difference in the breathing amplitudes in all patients and all fractions were 1.3 mm on average (95%-CI: [0.5-2.6] mm). CONCLUSION: The clinical integration of an optical surface scanner enables a stable and reliable DIBH treatment delivery during SGRT for left-sided breast cancer in clinical routine.


Assuntos
Suspensão da Respiração , Lesões por Radiação/prevenção & controle , Radioterapia Guiada por Imagem/métodos , Neoplasias Unilaterais da Mama/radioterapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Artefatos , Feminino , Humanos , Pessoa de Meia-Idade , Movimento (Física) , Órgãos em Risco/efeitos da radiação , Planejamento da Radioterapia Assistida por Computador/métodos , Reprodutibilidade dos Testes
3.
Technol Cancer Res Treat ; 17: 1533033818806002, 2018 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30453842

RESUMO

PURPOSE/OBJECTIVE: Reproducible patient positioning remains one of the major challenges in modern radiation therapy. Recently, optical surface scanners have been introduced into clinical practice in addition to well-established positioning systems, such as room laser and skin marks. The aim of this prospective study was to evaluate setup errors of the optical surface scanner Catalyst HD (C-RAD AB) in different anatomic regions. MATERIAL/METHODS: Between October 2016 and June 2017 a total of 1902 treatment sessions in 110 patients were evaluated. The workflow of this study included conventional setup procedures using laser-based positioning with skin marks and an additional registration of the 3-dimensional (3D) deviations detected by the Catalyst system. The deviations of the surface-based method were then compared to the corrections of cone beam computed tomography alignment which was considered as gold standard. A practical Catalyst setup error was calculated between the translational deviations of the surface scanner and the laser positioning. Two one-sided t tests for equivalence were used for statistical analysis. RESULTS: Data analysis revealed total deviations of 0.09 mm ± 2.03 mm for the lateral axis, 0.07 mm ± 3.21 mm for the longitudinal axis, and 0.44 mm ± 3.08 mm vertical axis for the Catalyst system, compared to -0.06 ± 3.54 mm lateral, 0.53 ± 3.47 mm longitudinal, and 0.19 ± 3.49 mm vertical for the laser positioning compared to cone beam computed tomography. The lowest positional deviations were found in the cranial region, and larger deviations occurred in the thoracic and abdominal sites. A statistical comparison using 2 one-sided t tests showed a general concordance of the 2 methods ( P ≤ 0.036), excluding the vertical direction of the abdominal region ( P = 0.198). CONCLUSION: The optical surface scanner Catalyst HD is a reliable and feasible patient positioning system without any additional radiation exposure. From the head to the thoracic and abdominal region, a decrease in accuracy was observed within a comparable range for Catalyst and laser-assisted positioning.


Assuntos
Neoplasias/patologia , Neoplasias/radioterapia , Posicionamento do Paciente , Radioterapia Guiada por Imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Tomografia Computadorizada de Feixe Cônico , Feminino , Humanos , Lasers , Masculino , Pessoa de Meia-Idade , Posicionamento do Paciente/métodos , Radioterapia Guiada por Imagem/métodos , Fluxo de Trabalho
4.
Radiat Oncol ; 13(1): 128, 2018 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-30012156

RESUMO

BACKGROUND: Intra-fraction motion represents a crucial issue in the era of precise radiotherapy in several settings, including breast irradiation. To date, only few data exist on real-time measured intra-fraction motion in breast cancer patients. Continuous surface imaging using visible light offers the capability to monitor patient movements in three-dimensional space without any additional radiation exposure. The aim of the present study was to quantify the uncertainties of possible intra-fractional motion during breast radiotherapy. MATERIAL AND METHODS: One hundred and four consecutive patients that underwent postoperative radiotherapy following breast conserving surgery or mastectomy were prospectively evaluated during 2028 treatment sessions. During each treatment session the patients' motion was continuously measured using the Catalyst™ optical surface scanner (C-RAD AB, Sweden) and compared to a reference scan acquired at the beginning of each session. The Catalyst system works through an optical surface imaging with light emitting diode (LED) light and reprojection captured by a charge coupled device (CCD) camera, which provide target position control during treatment delivery with a motion detection accuracy of 0.5 mm. For 3D surface reconstruction, the system uses a non-rigid body algorithm to calculate the distance between the surface and the isocentre and using the principle of optical triangulation. Three-dimensional deviations and relative position differences during the whole treatment fraction were calculated by the system and analyzed statistically. RESULTS: Overall, the maximum magnitude of the deviation vector showed a mean change of 1.93 mm ± 1.14 mm (standard deviation [SD]) (95%-confidence interval: [0.48-4.65] mm) and a median change of 1.63 mm during dose application (beam-on time only). Along the lateral and longitudinal axis changes were quite similar (0.18 mm ± 1.06 mm vs. 0.17 mm ± 1.32 mm), on the vertical axis the mean change was 0.68 mm ± 1.53 mm. The mean treatment session time was 154 ± 53 (SD) seconds and the mean beam-on time only was 55 ± 16 s. According to Friedman's test differences in the distributions of the three possible directions (lateral, longitudinal and vertical) were significant (p < 0.01), in post-hoc analysis there were no similarities between any two of the three directions. CONCLUSION: The optical surface imaging system is an accurate and easy tool for real-time motion management in breast cancer radiotherapy. Intra-fraction motion was reported within five millimeters in all directions. Thus, intra-fraction motion in our series of 2028 treatment sessions seems to be of minor clinical relevance in postoperative radiotherapy of breast cancer.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/radioterapia , Mama/diagnóstico por imagem , Movimentos dos Órgãos , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Neoplasias da Mama/cirurgia , Fracionamento da Dose de Radiação , Feminino , Humanos , Cuidados Pós-Operatórios , Estudos Prospectivos
5.
Z Geburtshilfe Neonatol ; 220(4): 179-82, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27294375

RESUMO

We report a case of pathological foetal Doppler velocity, specifically the absence of end diastolic flow in the umbilical artery (AEDV/REDV), suspected diabetic pregnancy and mesangioproliferative glomerulonephritis, at 32 weeks of gestation. The foetal heart rate tracings were evaluated using a computerised cardiotocogram (Oxford Sonicaid system 8002 Chichester, England) 1 for 20-30 min parallel to the routine cardiotocogram. The ultrasound control at 33 weeks of gestation showed oligohydramnion, foetal centralisation and reduced interval foetal growth. Due to small gestational age (SGA) and oligohydramnion, labour was induced at 36 weeks gestation with vaginal prostaglandin and an amniotomy. Due to cephalopelvic disproportion, a Caesarean section was performed. Signs and symptoms of neonatal lupus were not found.


Assuntos
Glomerulonefrite Membranoproliferativa/diagnóstico por imagem , Lúpus Eritematoso Sistêmico/diagnóstico por imagem , Complicações na Gravidez/diagnóstico por imagem , Gravidez em Diabéticas/diagnóstico por imagem , Ultrassonografia Pré-Natal/métodos , Diagnóstico Diferencial , Feminino , Humanos , Gravidez , Ultrassonografia Doppler Dupla/métodos
6.
Phys Rev Lett ; 110(24): 243603, 2013 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-25165922

RESUMO

We experimentally study the ground state coherence properties of cesium atoms in a nanofiber-based two-color dipole trap, localized ∼ 200 nm away from the fiber surface. Using microwave radiation to coherently drive the clock transition, we record Ramsey fringes as well as spin echo signals and infer a reversible dephasing time of T(2)(*) = 0.6 ms and an irreversible dephasing time of T(2)(') = 3.7 ms. By modeling the signals, we find that, for our experimental parameters, T(2)(*) and T(2)(') are limited by the finite initial temperature of the atomic ensemble and the heating rate, respectively. Our results represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in an optical fiber quantum network.

7.
S Afr J Surg ; 50(4): 136-7, 2012 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-23217557

RESUMO

Blunt liver trauma is commonly managed by non-operative measures. We report a case of an American Association for the Surgery of Trauma grade III liver injury and its complications, successfully managed by a combination of minimally invasive interventions.


Assuntos
Falso Aneurisma/terapia , Embolização Terapêutica , Hemobilia/etiologia , Hemobilia/terapia , Fígado/lesões , Ferimentos não Penetrantes/complicações , Adulto , Falso Aneurisma/complicações , Drenagem , Hemobilia/diagnóstico por imagem , Humanos , Masculino , Radiografia
8.
Phys Rev Lett ; 107(24): 243601, 2011 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-22242999

RESUMO

We dispersively interface an ensemble of 1000 atoms trapped in the evanescent field surrounding a tapered optical nanofiber. This method relies on the azimuthally asymmetric coupling of the ensemble with the evanescent field of an off-resonant probe beam, transmitted through the nanofiber. The resulting birefringence and dispersion are significant; we observe a phase shift per atom of ∼1 mrad at a detuning of 6 times the natural linewidth, corresponding to an effective resonant optical density per atom of 0.027. Moreover, we utilize this strong dispersion to nondestructively determine the number of atoms.

9.
Phys Rev Lett ; 104(20): 203603, 2010 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-20867028

RESUMO

Trapping and optically interfacing laser-cooled neutral atoms are essential requirements for their use in advanced quantum technologies. Here we simultaneously realize both of these tasks with cesium atoms interacting with a multicolor evanescent field surrounding an optical nanofiber. The atoms are localized in a one-dimensional optical lattice about 200 nm above the nanofiber surface and can be efficiently interrogated with a resonant light field sent through the nanofiber. Our technique opens the route towards the direct integration of laser-cooled atomic ensembles within fiber networks, an important prerequisite for large scale quantum communication schemes. Moreover, it is ideally suited to the realization of hybrid quantum systems that combine atoms with, e.g., solid state quantum devices.

10.
Bioorg Med Chem Lett ; 10(3): 277-9, 2000 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-10698453

RESUMO

A series of 2,3-disubstituted-4-phenylquinolines were prepared and were found to inhibit the apical sodium co-dependent bile acid transporter (ASBT). Alkyl and ester substitution at the 3-position showed comparable activities while substitution at the 2-position was much more sensitive to the nature of the substituent. The synthesis and in vitro potency data are presented for this novel class of compounds.


Assuntos
Proteínas de Transporte/antagonistas & inibidores , Hidroxiesteroide Desidrogenases , Glicoproteínas de Membrana , Quinolinas/farmacologia , Sódio/farmacologia , Estrutura Molecular , Quinolinas/química
11.
J Med Chem ; 39(9): 1846-56, 1996 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-8627608

RESUMO

A novel series of terphenyl methyl sulfones and sulfonamides have been shown to be highly potent and selective cyclooxygenase-2 (COX-2) inhibitors. The sulfonamide analogs 17 and 21 were found to be much more potent COX-2 inhibitors and orally active anti-inflammatory agents than the corresponding methyl sulfone analogs 16 and 20, respectively, albeit with some decrease in COX-2 selectivity. Structure-activity relationship studies have determined that incorporation of two fluorine atoms in the central phenyl group, as in 20 and 21, is extremely advantageous for both in vitro COX-2 potency and selectivity as well as in vivo activity. Several noticeable examples in the 1,2-diaryl-4,5-difluorobenzenesulfonamide series are 21a-c,k,l,n (COX-2, IC50 = 0.002-0.004 microM), in which all have in vitro COX-1/COX-2 selectivity > 1000. In addition, sulfonamides 21a,b,d,g,j,m,n,q were shown to have greatly enhanced oral activity with more than 90% inhibition of prostaglandin E2 production in the air pouch model of inflammation. Furthermore, sulfonamide 21b was found to be very active in the rat adjuvant-induced arthritis model (ED50 = 0.05 mg/kg) and carrageenan-induced hyperalgesia assay (ED50 = 38.7 mg/kg) with no indication of gastrointestinal toxicity in rats at doses as high as 200 mg/kg.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Inibidores de Ciclo-Oxigenase/farmacologia , Isoenzimas/efeitos dos fármacos , Prostaglandina-Endoperóxido Sintases/efeitos dos fármacos , Compostos de Terfenil/farmacologia , Administração Oral , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/uso terapêutico , Artrite Experimental/tratamento farmacológico , Ciclo-Oxigenase 2 , Inibidores de Ciclo-Oxigenase 2 , Inibidores de Ciclo-Oxigenase/administração & dosagem , Inibidores de Ciclo-Oxigenase/química , Inibidores de Ciclo-Oxigenase/uso terapêutico , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Ratos , Compostos de Terfenil/administração & dosagem , Compostos de Terfenil/química , Compostos de Terfenil/uso terapêutico
12.
J Med Chem ; 39(1): 253-66, 1996 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-8568815

RESUMO

A novel series of 5,6-diarylspiro[2.4]hept-5-enes was shown to provide highly potent and selective cyclooxygenase-2 (COX-2) inhibitors. A study of structure-activity relationships in this series suggests that 3,4-disubstituted phenyl analogs are generally more selective than 4-substituted phenyl analogs and that replacement of the methyl sulfone group on the 6-phenyl ring with a sulfonamide moiety results in compounds with superior in vivo pharmacological properties, although with lower COX-2 selectivity. Several compounds have been shown to possess promising pharmacological properties in adjuvant-induced arthritis and edema analgesia models. The absence of gastrointestinal (GI) toxicity at 200 mpk of several selected compounds in rats and mice corresponds well with the weak potency for inhibition of COX-1 observed in the enzyme assay. Methyl sulfone 55 and sulfonamide 24 were shown to have superior in vivo pharmacological profiles, low GI toxicity, and good oral bioavailability and duration of action.


Assuntos
Anti-Inflamatórios não Esteroides/química , Inibidores de Ciclo-Oxigenase/síntese química , Compostos de Espiro/síntese química , Sulfonamidas/síntese química , Sulfonas/síntese química , Analgésicos/síntese química , Analgésicos/farmacologia , Animais , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/farmacocinética , Anti-Inflamatórios não Esteroides/farmacologia , Artrite Experimental/tratamento farmacológico , Carragenina/farmacologia , Inibidores de Ciclo-Oxigenase/farmacocinética , Inibidores de Ciclo-Oxigenase/farmacologia , Edema/tratamento farmacológico , Humanos , Intestinos/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Ratos , Ratos Endogâmicos Lew , Ratos Sprague-Dawley , Compostos de Espiro/química , Compostos de Espiro/farmacocinética , Compostos de Espiro/farmacologia , Estômago/efeitos dos fármacos , Relação Estrutura-Atividade , Sulfonamidas/química , Sulfonamidas/farmacocinética , Sulfonamidas/farmacologia , Sulfonas/química , Sulfonas/farmacocinética , Sulfonas/farmacologia
14.
Mol Pharmacol ; 47(1): 115-20, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7838120

RESUMO

SC-54628 [1-(2-methylphenyl)-4-butyl-1,3-dihydro-3-[[6-[2-(1H- tetrazol-5-yl)phenyl]-3-pyridinyl]methyl]-2H-imidazol-2-one] and its 1-(2,6-dimethylphenyl)-2H-imidazol-2-one derivative SC-54629 were potent inhibitors of 125I-angiotensin II (125I-AII) binding to rat adrenal cortex angiotensin type 1 (AT1) receptors. SC-54628 and SC-54629 antagonized AII-induced contraction of rabbit vascular smooth muscle in a surmountable fashion and an insurmountable fashion, respectively. Binding experiments with SC-54629 were undertaken to determine the nature of receptor interaction, which might explain the insurmountable mode of antagonism of SC-54629. The presence of a high concentration of SC-54629 did not affect the dissociation of membrane-bound 125I-AII induced by an excess of unlabeled AII, indicating that the antagonist binds to the agonist binding site and not an allosteric domain. Incubation of adrenal cortex membranes with SC-54629 decreased the density of 125I-AII binding sites. When incubation of the SC-54629-treated membranes with radiolabeled AII was prolonged, the SC-54629-induced decrease in AT1 receptor density was attenuated, suggesting that binding of the antagonist is slowly reversible. Furthermore, the dissociation of [3H]SC-54629 was 5-fold slower than that of 125I-AII bound to AT1 receptors. These results suggest that the insurmountable antagonism of AII by SC-54629 is most likely due to the slow reversibility of SC-54629 binding to the AT1 receptor.


Assuntos
Angiotensina II/metabolismo , Antagonistas de Receptores de Angiotensina , Imidazóis/farmacologia , Angiotensina II/farmacologia , Animais , Sítios de Ligação , Imidazóis/metabolismo , Técnicas In Vitro , Radioisótopos do Iodo , Cinética , Masculino , Contração Muscular/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/fisiologia , Coelhos , Ratos , Receptores de Angiotensina/agonistas , Receptores de Angiotensina/metabolismo
17.
Am J Hypertens ; 6(7 Pt 1): 619-25, 1993 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8398003

RESUMO

The depressor activity of a novel nonpeptidic angiotensin II (AII) receptor antagonist, SC-51316 (2,5-dibutyl-2,4-dihydro-4-[[2-(1H-tetrazol-5-yl)[1,1'-biphenyl]-4 '- yl]-methyl]-3H-1,2,4-triazol-3-one), is described. In anesthetized, ganglion-blocked rats, intravenous administration of SC-51316 inhibited the pressor response to an infusion of AII. To determine antihypertensive efficacy, conscious, spontaneously hypertensive rats were administered SC-51316 (30 mg/kg intragastrically) daily for 5 days. Blood pressure was reduced in a similar manner to that observed with the angiotensin converting enzyme inhibitor enalapril (10 mg/kg intragastrically). SC-51316 had no effect on heart rate. In conscious, sodium-deficient dogs, administration of SC-51316 (30 mg/kg orally) or enalapril (10 mg/kg orally) lowered blood pressure similarly over a 24 h observation period. Thus, SC-51316 antagonizes the activity of AII in vivo and is an orally active, antihypertensive agent.


Assuntos
Antagonistas de Receptores de Angiotensina , Pressão Sanguínea/efeitos dos fármacos , Hipertensão/tratamento farmacológico , Tetrazóis/farmacologia , Triazóis/farmacologia , Angiotensina II/antagonistas & inibidores , Angiotensina II/fisiologia , Animais , Compostos de Bifenilo/farmacologia , Compostos de Bifenilo/uso terapêutico , Depressão Química , Cães , Relação Dose-Resposta a Droga , Enalapril/farmacologia , Enalapril/uso terapêutico , Imidazóis/farmacologia , Imidazóis/uso terapêutico , Losartan , Masculino , Ratos , Ratos Endogâmicos SHR , Ratos Sprague-Dawley , Tetrazóis/uso terapêutico , Triazóis/uso terapêutico
18.
J Med Chem ; 36(15): 2172-81, 1993 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-8340920

RESUMO

2,5-Dibutyl-2,4-dihydro-4-[[2-(1H-tetrazol-5-yl)[1,1'-biphenyl]-4' - yl]methyl]-3H-1,2,4-triazol-3-one, SC-51316, was synthesized as a potent and orally active angiotensin II (AII) receptor antagonist with a long duration of action. To explore the lipophilic pocket in the AII receptor interacting with the substituent at the 2-position of triazolone-based antagonists, a series of compounds were prepared and evaluated for receptor binding affinity and antagonism of AII-contracted rabbit aortic rings. It has been found that the pocket is very spacious and can accommodate different sizes of lipophilic groups and various functionalities. Acidic groups generally result in a slight decrease in binding affinity. Branched chains are unfavorable. The freedom of rotation around C2-C3 in the flexible side chain is crucial for good binding. The 2-phenylethyl-substituted triazolone analogue exhibits the highest in vitro potency among all compounds that have been synthesized.


Assuntos
Antagonistas de Receptores de Angiotensina , Tetrazóis/síntese química , Tetrazóis/farmacologia , Triazóis/síntese química , Triazóis/farmacologia , Animais , Sítios de Ligação , Feminino , Músculo Liso/efeitos dos fármacos , Músculo Liso/metabolismo , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Coelhos , Ratos , Relação Estrutura-Atividade , Tetrazóis/metabolismo , Triazóis/metabolismo , Útero/efeitos dos fármacos , Útero/metabolismo
19.
J Med Chem ; 36(1): 101-10, 1993 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-8421274

RESUMO

A series of 5-[1-[4-[(4,5-disubstituted-1H-imidazol-1-yl)methyl]- substituted]-1H-pyrrol-2-yl]-1H-tetrazoles and 5-[1-[4-[(3,5-dibutyl-1H-1,2,4-triazol-1-yl)methyl]-substituted]- 1H-pyrrol-2-yl]-1H-tetrazoles were investigated as novel AT1-selective angiotensin II receptor antagonists. Computer-assisted modeling techniques were used to evaluate structural parameters in comparison to the related biphenyl system. New synthetic procedures have been developed to prepare the novel compounds. The best antagonists in this series had IC50 values (rat uterine membrane receptor binding) in the 10(-8) M range and corresponding pA2 in isolated organ assay (rabbit aorta rings). Structure-activity relationships indicate some similarities with the finding in the biphenyl system. Substitution on the pyrrole ring modulates activity. Compound 5 antagonized angiotensin-induced blood pressure increase when administered to conscious rat at 30 mg/kg per os.


Assuntos
Angiotensina II/antagonistas & inibidores , Antagonistas de Receptores de Angiotensina , Pirróis/síntese química , Animais , Sítios de Ligação/efeitos dos fármacos , Feminino , Masculino , Músculo Liso Vascular/efeitos dos fármacos , Pirróis/metabolismo , Pirróis/farmacologia , Coelhos , Ratos , Ratos Sprague-Dawley , Receptores de Angiotensina/metabolismo , Relação Estrutura-Atividade , Útero/efeitos dos fármacos , Útero/metabolismo
20.
J Pharmacol Exp Ther ; 261(3): 1037-43, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1602371

RESUMO

The properties of a novel nonpeptidic angiotensin II (AII) receptor antagonist, 2,5-dibutyl-2,4-dihydro-4-([2-(1H-tetrazol-5-yl)(1,1'-biphenyl) -4'-yl]methyl)-3H-1,2,4-triazol-3-one (SC-51316), are described. SC-51316 inhibited [125I]AII binding selectively to the AT1 receptor with IC50 values of 3.6 and 5.1 nM in rat adrenal cortical and rat uterine membrane preparations, respectively. The compound was a competitive and reversible antagonist of AII-mediated contraction of rabbit aortic rings with a pA2 of 8.86. In addition, SC-51316 inhibited AII-induced aldosterone release from rat adrenal zona glomerulosa cells and blocked inhibition of renin release by AII from rat kidney slices with pA2 values of 8.62 and 8.9, respectively. The agent (0.1 mM) did not inhibit angiotensin-converting enzyme or plasma renin activity. These data demonstrate that SC-51316 is a potent AII receptor antagonist which may prove to be useful as a pharmacologic tool for studying the role of the renin-angiotensin system in cardiovascular diseases.


Assuntos
Angiotensina II/antagonistas & inibidores , Angiotensina II/metabolismo , Compostos de Bifenilo/farmacologia , Imidazóis/farmacologia , Receptores de Angiotensina/efeitos dos fármacos , Tetrazóis/farmacologia , Triazóis/farmacologia , Córtex Suprarrenal/efeitos dos fármacos , Córtex Suprarrenal/metabolismo , Aldosterona/metabolismo , Antagonistas de Receptores de Angiotensina , Animais , Membrana Celular/efeitos dos fármacos , Feminino , Rim/efeitos dos fármacos , Rim/metabolismo , Losartan , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Ratos , Receptores de Angiotensina/metabolismo , Renina/sangue , Útero/efeitos dos fármacos
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