RESUMO
Abstract Salinity, of both soil and water, is one of the main causes of crop yield decline. Within this context, the objective of this study was to evaluate the influence of different salts on the germination of chia seeds. The experiment was conducted in a BOD chamber at a constant temperature of 20 °C and in the presence of light. The seeds were placed on paper soaked with aqueous solutions of calcium chloride (CaCl2), sodium chloride (NaCl), potassium chloride (KCl), and magnesium chloride (MgCl2), at the osmotic potentials zero, -0.10, -0.20, -0.30, and -0.40 MPa. The effect of the salinity was evaluated using a germination test, with counts on days 7 and 14 after sowing. Based on the results, chia seeds tolerate concentrations of NaCl to -0.4 MPa and KCl to -0.20 MPa. The salts CaCl2 and MgCl2 had a negative effect on the germination and vigor of the chia seeds for the osmotic potentials -0.30 MPa and -0.20 MPa, respectively.
Resumo A salinidade, tanto dos solos como das águas, é uma das principais causas da queda de rendimento das culturas. Neste contexto, o objetivo deste estudo foi avaliar a influência de diferentes sais na germinação de sementes de chia. O experimento foi conduzido em câmara BOD, na temperatura constante de 20 °C e em presença de luz. As sementes foram colocadas sobre papel embebido em soluções aquosas de cloreto de cálcio (CaCl2), cloreto de sódio (NaCl), cloreto de potássio (KCl) e cloreto de magnésio (MgCl2) nos potenciais osmóticos correspondentes a zero; -0,10; -0,20; -0,30 e -0,40 MPa. O efeito da salinidade foi avaliado através do teste de germinação com contagens aos 7 dias e 14 dias após a semeadura. De acordo com os resultados é possível concluir que as sementes de chia toleram concentrações de NaCl até -0,4 MPa e KCl até -0,20 MPa. Os sais CaCl2 e MgCl2 apresentam efeito negativo sobre a germinação e o vigor das sementes de chia a partir dos potenciais osmóticos de -0,30 MPa e -0,20 MPa, respectivamente.
Assuntos
Cloreto de Sódio , Salinidade , Sementes , Temperatura , Água , GerminaçãoRESUMO
Salinity, of both soil and water, is one of the main causes of crop yield decline. Within this context, the objective of this study was to evaluate the influence of different salts on the germination of chia seeds. The experiment was conducted in a BOD chamber at a constant temperature of 20 °C and in the presence of light. The seeds were placed on paper soaked with aqueous solutions of calcium chloride (CaCl2), sodium chloride (NaCl), potassium chloride (KCl), and magnesium chloride (MgCl2), at the osmotic potentials zero, -0.10, -0.20, -0.30, and -0.40 MPa. The effect of the salinity was evaluated using a germination test, with counts on days 7 and 14 after sowing. Based on the results, chia seeds tolerate concentrations of NaCl to -0.4 MPa and KCl to -0.20 MPa. The salts CaCl2 and MgCl2 had a negative effect on the germination and vigor of the chia seeds for the osmotic potentials -0.30 MPa and -0.20 MPa, respectively.
Assuntos
Salinidade , Cloreto de Sódio , Germinação , Sementes , Temperatura , ÁguaRESUMO
Salinity, of both soil and water, is one of the main causes of crop yield decline. Within this context, the objective of this study was to evaluate the influence of different salts on the germination of chia seeds. The experiment was conducted in a BOD chamber at a constant temperature of 20 °C and in the presence of light. The seeds were placed on paper soaked with aqueous solutions of calcium chloride (CaCl2), sodium chloride (NaCl), potassium chloride (KCl), and magnesium chloride (MgCl2), at the osmotic potentials zero, -0.10, -0.20, -0.30, and -0.40 MPa. The effect of the salinity was evaluated using a germination test, with counts on days 7 and 14 after sowing. Based on the results, chia seeds tolerate concentrations of NaCl to -0.4 MPa and KCl to -0.20 MPa. The salts CaCl2 and MgCl2 had a negative effect on the germination and vigor of the chia seeds for the osmotic potentials -0.30 MPa and -0.20 MPa, respectively.(AU)
A salinidade, tanto dos solos como das águas, é uma das principais causas da queda de rendimento das culturas. Neste contexto, o objetivo deste estudo foi avaliar a influência de diferentes sais na germinação de sementes de chia. O experimento foi conduzido em câmara BOD, na temperatura constante de 20 °C e em presença de luz. As sementes foram colocadas sobre papel embebido em soluções aquosas de cloreto de cálcio (CaCl2), cloreto de sódio (NaCl), cloreto de potássio (KCl) e cloreto de magnésio (MgCl2) nos potenciais osmóticos correspondentes a zero; -0,10; -0,20; -0,30 e -0,40 MPa. O efeito da salinidade foi avaliado através do teste de germinação com contagens aos 7 dias e 14 dias após a semeadura. De acordo com os resultados é possível concluir que as sementes de chia toleram concentrações de NaCl até -0,4 MPa e KCl até -0,20 MPa. Os sais CaCl2 e MgCl2 apresentam efeito negativo sobre a germinação e o vigor das sementes de chia a partir dos potenciais osmóticos de -0,30 MPa e -0,20 MPa, respectivamente.(AU)
Assuntos
Salvia/crescimento & desenvolvimento , Germinação , Estresse SalinoRESUMO
Abstract Salinity, of both soil and water, is one of the main causes of crop yield decline. Within this context, the objective of this study was to evaluate the influence of different salts on the germination of chia seeds. The experiment was conducted in a BOD chamber at a constant temperature of 20 °C and in the presence of light. The seeds were placed on paper soaked with aqueous solutions of calcium chloride (CaCl2), sodium chloride (NaCl), potassium chloride (KCl), and magnesium chloride (MgCl2), at the osmotic potentials zero, -0.10, -0.20, -0.30, and -0.40 MPa. The effect of the salinity was evaluated using a germination test, with counts on days 7 and 14 after sowing. Based on the results, chia seeds tolerate concentrations of NaCl to -0.4 MPa and KCl to -0.20 MPa. The salts CaCl2 and MgCl2 had a negative effect on the germination and vigor of the chia seeds for the osmotic potentials -0.30 MPa and -0.20 MPa, respectively.
Resumo A salinidade, tanto dos solos como das águas, é uma das principais causas da queda de rendimento das culturas. Neste contexto, o objetivo deste estudo foi avaliar a influência de diferentes sais na germinação de sementes de chia. O experimento foi conduzido em câmara BOD, na temperatura constante de 20 °C e em presença de luz. As sementes foram colocadas sobre papel embebido em soluções aquosas de cloreto de cálcio (CaCl2), cloreto de sódio (NaCl), cloreto de potássio (KCl) e cloreto de magnésio (MgCl2) nos potenciais osmóticos correspondentes a zero; -0,10; -0,20; -0,30 e -0,40 MPa. O efeito da salinidade foi avaliado através do teste de germinação com contagens aos 7 dias e 14 dias após a semeadura. De acordo com os resultados é possível concluir que as sementes de chia toleram concentrações de NaCl até -0,4 MPa e KCl até -0,20 MPa. Os sais CaCl2 e MgCl2 apresentam efeito negativo sobre a germinação e o vigor das sementes de chia a partir dos potenciais osmóticos de -0,30 MPa e -0,20 MPa, respectivamente.
RESUMO
Abstract Salinity, of both soil and water, is one of the main causes of crop yield decline. Within this context, the objective of this study was to evaluate the influence of different salts on the germination of chia seeds. The experiment was conducted in a BOD chamber at a constant temperature of 20 °C and in the presence of light. The seeds were placed on paper soaked with aqueous solutions of calcium chloride (CaCl2), sodium chloride (NaCl), potassium chloride (KCl), and magnesium chloride (MgCl2), at the osmotic potentials zero, -0.10, -0.20, -0.30, and -0.40 MPa. The effect of the salinity was evaluated using a germination test, with counts on days 7 and 14 after sowing. Based on the results, chia seeds tolerate concentrations of NaCl to -0.4 MPa and KCl to -0.20 MPa. The salts CaCl2 and MgCl2 had a negative effect on the germination and vigor of the chia seeds for the osmotic potentials -0.30 MPa and -0.20 MPa, respectively.
Resumo A salinidade, tanto dos solos como das águas, é uma das principais causas da queda de rendimento das culturas. Neste contexto, o objetivo deste estudo foi avaliar a influência de diferentes sais na germinação de sementes de chia. O experimento foi conduzido em câmara BOD, na temperatura constante de 20 °C e em presença de luz. As sementes foram colocadas sobre papel embebido em soluções aquosas de cloreto de cálcio (CaCl2), cloreto de sódio (NaCl), cloreto de potássio (KCl) e cloreto de magnésio (MgCl2) nos potenciais osmóticos correspondentes a zero; -0,10; -0,20; -0,30 e -0,40 MPa. O efeito da salinidade foi avaliado através do teste de germinação com contagens aos 7 dias e 14 dias após a semeadura. De acordo com os resultados é possível concluir que as sementes de chia toleram concentrações de NaCl até -0,4 MPa e KCl até -0,20 MPa. Os sais CaCl2 e MgCl2 apresentam efeito negativo sobre a germinação e o vigor das sementes de chia a partir dos potenciais osmóticos de -0,30 MPa e -0,20 MPa, respectivamente.
RESUMO
RESUMO: A espécie Polygonum punctatum Elliott (Polygonaceae) é amplamente utilizada pela população como planta medicinal. O objetivo deste trabalho é o de avaliar o potencial genotóxico e mutagênico de P. punctatum utilizando raízes de bulbos e radículas em sementes germinadas de Allium cepa através do teste in vivo, e realizar comparações da extração do material vegetal por calor (infusões) e extração a frio (extrato). Para isso, foram preparadas dois tipos de soluções, infusões e extratos foliares de P. punctatum, em duas concentrações 0,4 g mL-1 e 2,4 g mL-1. A infusão foi preparada pela adição das folhas secas em água destilada fervente (100ºC), permanecendo por 10 minutos enquanto o extrato foi preparado através da maceração das folhas secas em água destilada fria. Para o teste em A. cepa foram utilizados, para cada tratamento, seis grupos de quatro bulbos e seis caixas gerbox com 50 sementes em cada caixa. Duas lâminas para cada tratamento foram obtidas através da técnica de esmagamento das raízes e coradas com orceína acética 2%. Foram contadas 2000 células por grupo de bulbos e 3000 células por grupo de sementes, observando-se a ocorrência de interrupções em metáfases, alterações cromossômicas estruturais, bem como a inibição ou aumento da divisão celular. Os valores do índice mitótico foram calculados e analisados estatisticamente pelo Teste χ2 (p≤0,05). Os resultados demonstraram que as infusões e os extratos de folhas apresentaram redução nos valores de índices mitóticos nas concentrações utilizadas em relação ao controle em água destilada. Foram identificadas alterações cromossômicas na divisão celular, tais como pontes anafásicas, em todas as concentrações de infusões e extratos indicando assim que P. punctatum possui atividade antiproliferativa e genotóxica.
ABSTRACT: The species Polygonum punctatum Elliott (Polygonaceae) is widely used by the Brazilian population as a medicinal plant. The aims of this study are to evaluate the genotoxic and mutagenic potential of P. punctatum, using its root bulbs and rootlets in germinated seeds of Allium cepa by in vivo testing, and to compare the extraction of plant material by heat (infusions) and cold (extract). Thus, two types of solutions - infusions and leaf extracts - of P. punctatum were prepared at the two concentrations of 0.4 g ml -1 and 2.4 g mL- 1. The infusion was prepared by addition of dry leaves in boiling distilled water (100ºC), remaining for 10 minutes, while the extract was prepared by maceration of dried leaves in cold distilled water. For the A. cepa, we used for each treatment six groups of six bulbs and six seedling boxes with 50 seeds each. Two slides for each treatment were obtained by the technique of crushing the roots, and they were stained with 2 % acetic orcein. For the analysis, 2000 cells per group of bulbs and 3000 cells per group of seeds were counted, and we noted the occurrence of interruptions in the metaphase, chromosomal aberrations, as well as inhibited or increased cell division. The values of the mitotic index were calculated and statistically analyzed by the χ2 test (p ≤ 0.05). The results showed that the infusions and extracts of leaves showed reduced values of mitotic indices in the concentrations used compared to the control in distilled water. Chromosomal alterations were identified in the cell division, in all concentrations of infusions and extracts, thus indicating that P. punctatum has an antiproliferative and genotoxic activity.
Assuntos
Cebolas/classificação , Polygonum/metabolismo , Genotoxicidade/análise , Mutagênicos/análise , Plantas Medicinais/classificaçãoRESUMO
RESUMO A Salvia hispanica, conhecida popularmente como chia, apresenta elevada notabilidade por suas características nutricionais, sendo rica em proteínas, fibras, sais minerais e ácidos graxos, os quais podem ser responsáveis pela diminuição do risco de doenças cardiovasculares. Apesar do crescente consumo, existem poucos estudos em relação à germinação e ao vigor de suas sementes. Assim, o presente trabalho teve como objetivo avaliar os efeitos da luz e da temperatura no potencial fisiológico de sementes de chia (Salvia hispanica L.). Para tal, as sementes foram colocadas para germinar nas temperaturas constantes de 20, 25 e 30 ºC na presença e ausência de luz. Os parâmetros avaliados foram: percentagem de germinação, primeira contagem, índice de velocidade de germinação, e comprimento e massa seca das plântulas. O delineamento experimental utilizado foi inteiramente casualizado com quatro repetições de 100 sementes. Constatou-se que a germinação das sementes de chia ocorre tanto na presença quanto na ausência de luz. As sementes de chia, sem dormência, germinam melhor na temperatura constante de 20 °C.
ABSTRACT The Salvia hispanica, known as chia, has high notability for its nutritional features, being rich in protein, fiber, minerals and fatty acids, which can be responsible for reducing the risk of cardiovascular diseases. Although the consumption of the seed is increasing, there are few studies about the germination and vigor of the seeds. The aim of this study was to evaluate the effects of light and temperature on the physiologic potentiality of chia seeds (Salvia hispanica L.). The seeds were sowed on paper at constant temperatures of 20, 25 and 30 ºC in the presence or absence of light. The parameters evaluated were the following: percentage of germination, first count, germination speed index, length, and dry weight of the seedlings. The experimental design used was of complete randomized plots with four replications of 100 seeds. The germination of the chia seeds occurred in the presence or absence of light. The chia seeds, without dormancy, germinated better at the constant temperature of 20 ºC.
Assuntos
Temperatura , Lamiaceae/classificação , Plantas Medicinais/classificação , Sementes/classificaçãoRESUMO
The Finite Element Method is a well-known technique, being extensively applied in different areas. Studies using the Finite Element Method (FEM) are targeted to improve cardiac ablation procedures. For such simulations, the finite element meshes should consider the size and histological features of the target structures. However, it is possible to verify that some methods or tools used to generate meshes of human body structures are still limited, due to nondetailed models, nontrivial preprocessing, or mainly limitation in the use condition. In this paper, alternatives are demonstrated to solid modeling and automatic generation of highly refined tetrahedral meshes, with quality compatible with other studies focused on mesh generation. The innovations presented here are strategies to integrate Open Source Software (OSS). The chosen techniques and strategies are presented and discussed, considering cardiac structures as a first application context.
RESUMO
This work was designed to study the expression of the vasodilator peptide angiotensin-(1-7) [Ang-(1-7)] and its generating enzyme (ACE2) in the uteroplacental interface. Placentas were obtained from 11 early pregnancy failures (5 miscarriages and 6 ectopic pregnancies), 15 normotensive, and 10 preeclamptic gestations. In placental villi, the main sites of immunocytochemical expression of Ang-(1-7) and ACE2 were the syncytiotrophoblast, cytotrophoblast, endothelium and vascular smooth muscle of primary and secondary villi. Syncitial Ang-(1-7) expression in samples obtained from miscarriages and ectopic pregnancies was increased compared to normal term pregnancy [2.0 (2.0-2.25 for the 25 and 75% interquartile range) vs 1.3 (1.0-1.9), p<0.01]. In the maternal stroma, Ang-(1-7) and ACE2 were expressed in the invading and intravascular trophoblast and in decidual cells in all 3 groups. Ang-(1-7) and ACE2 staining was also found in arterial and venous endothelium and smooth muscle of the umbilical cord. The expression of Ang-(1-7) and ACE2 was similar in samples obtained from normal term or preeclamptic pregnancies, except for increased expression of ACE2 in umbilical arterial endothelium in preeclampsia [0.5 (0.5-0.8) vs 0.0 (0.0-0.0), p<0.01]. The uteroplacental location of Ang-(1-7) and ACE2 in pregnancy suggests an autocrine function of Ang-(1-7) in the vasoactive regulation that characterizes placentation and established pregnancy.
Assuntos
Angiotensina I/análise , Carboxipeptidases/análise , Fragmentos de Peptídeos/análise , Placenta/química , Complicações na Gravidez/metabolismo , Gravidez/metabolismo , Angiotensina I/metabolismo , Enzima de Conversão de Angiotensina 2 , Carboxipeptidases/metabolismo , Feminino , Humanos , Imuno-Histoquímica , Fragmentos de Peptídeos/metabolismo , Peptidil Dipeptidase A , Placenta/enzimologia , Placenta/metabolismo , Pré-Eclâmpsia/metabolismo , Complicações na Gravidez/enzimologiaRESUMO
Pregnancy is a physiological condition characterized by a progressive increase of the different components of the renin-angiotensin system (RAS). The physiological consequences of the stimulated RAS in normal pregnancy are incompletely understood, and even less understood is the question of how this system may be altered and contribute to the hypertensive disorders of pregnancy. Findings from our group have provided novel insights into how the RAS may contribute to the physiological condition of pregnancy by showing that pregnancy increases the expression of both the vasodilator heptapeptide of the RAS, angiotensin-(1-7) [Ang-(1-7)], and of a newly cloned angiotensin converting enzyme (ACE) homolog, ACE2, that shows high catalytic efficiency for Ang II metabolism to Ang-(1-7). The discovery of ACE2 adds a new dimension to the complexity of the RAS by providing a new arm that may counter-regulate the activity of the vasoconstrictor component, while amplifying the vasodilator component. The studies reviewed in this article demonstrate that Ang-(1-7) increases in plasma and urine of normal pregnant women. In preeclamptic subjects we showed that plasma Ang-(1-7) was suppressed as compared to the levels found in normal pregnancy. In addition, kidney and urinary levels of Ang-(1-7) were increased in pregnant rats coinciding with the enhanced detection and expression of ACE2. These findings support the concept that in normal pregnancy enhanced ACE2 may counteract the elevation in tissue and circulating Ang II by increasing the rate of conversion to Ang-(1-7). These findings provide a basis for the physiological role of Ang-(1-7) and ACE2 during pregnancy.
Assuntos
Humanos , Animais , Feminino , Gravidez , Ratos , Angiotensina I , Peptidil Dipeptidase A , Pré-Eclâmpsia , Sistema Renina-Angiotensina , BiomarcadoresRESUMO
Pregnancy is a physiological condition characterized by a progressive increase of the different components of the renin-angiotensin system (RAS). The physiological consequences of the stimulated RAS in normal pregnancy are incompletely understood, and even less understood is the question of how this system may be altered and contribute to the hypertensive disorders of pregnancy. Findings from our group have provided novel insights into how the RAS may contribute to the physiological condition of pregnancy by showing that pregnancy increases the expression of both the vasodilator heptapeptide of the RAS, angiotensin-(1-7) [Ang-(1-7)], and of a newly cloned angiotensin converting enzyme (ACE) homolog, ACE2, that shows high catalytic efficiency for Ang II metabolism to Ang-(1-7). The discovery of ACE2 adds a new dimension to the complexity of the RAS by providing a new arm that may counter-regulate the activity of the vasoconstrictor component, while amplifying the vasodilator component. The studies reviewed in this article demonstrate that Ang-(1-7) increases in plasma and urine of normal pregnant women. In preeclamptic subjects we showed that plasma Ang-(1-7) was suppressed as compared to the levels found in normal pregnancy. In addition, kidney and urinary levels of Ang-(1-7) were increased in pregnant rats coinciding with the enhanced detection and expression of ACE2. These findings support the concept that in normal pregnancy enhanced ACE2 may counteract the elevation in tissue and circulating Ang II by increasing the rate of conversion to Ang-(1-7). These findings provide a basis for the physiological role of Ang-(1-7) and ACE2 during pregnancy.
Assuntos
Angiotensina I/metabolismo , Fragmentos de Peptídeos/metabolismo , Peptidil Dipeptidase A/metabolismo , Pré-Eclâmpsia/sangue , Gravidez/metabolismo , Sistema Renina-Angiotensina/fisiologia , Angiotensina I/sangue , Angiotensina I/urina , Animais , Biomarcadores , Feminino , Humanos , Fragmentos de Peptídeos/sangue , Fragmentos de Peptídeos/urina , Peptidil Dipeptidase A/sangue , Peptidil Dipeptidase A/urina , Gravidez/sangue , Gravidez/urina , RatosRESUMO
Ang-(1-7) is an effector peptide of the renin-angiotensin system with several distinct actions that are likely mediated by a specific receptor. Regulatory effects of angiotensin (Ang) peptides, Ang-(1-7) and Ang II, on Ang receptor subtype 1 (AT1) mRNA expression were investigated in vascular smooth muscle cells (VSMC) from four University of Akron (Akr) rat strains (WKY, SHR and two backcross consomic lines SHR/y and SHR/a), and in SHR and WKY cells from Charles River Laboratories (Crl). In WKY/Akr and SHR/Akr, Ang-(1-7) treatment increased the levels of AT1 mRNA. This effect was inhibited by the specific Ang-(1-7) antagonist, A-779, in WKY/Akr but not SHR/Akr. Ang II had no effect in Akr cells, but it down-regulated AT1 mRNA in WKY/Crl and SHR/Crl VSMC. Ang-(1-7) did not affect AT1 mRNA levels in Crl lines. In conclusion, Ang-(1-7) regulates the AT1 receptor either directly or indirectly in a strain-specific fashion. The Ang-(1-7) antagonist, A-779, blocks the actions of Ang-(1-7) only in VSMC from WKY/Akr rats, suggesting either that the binding sites for Ang-(1-7) have different properties in SHR/Akr and WKY/Akr cell lines, or that some of the effects of Ang-(1-7) are not receptor mediated. Further, we found differences between Akr cells and Crl cells that are consistent with their genetic heterogeneity.
Assuntos
Angiotensina I/farmacologia , Aorta Torácica/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Fragmentos de Peptídeos/farmacologia , Receptores de Angiotensina/genética , Transcrição Gênica/efeitos dos fármacos , Animais , Anti-Hipertensivos/farmacologia , Cruzamentos Genéticos , Masculino , RNA Mensageiro/genética , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY , Receptor Tipo 1 de Angiotensina , Receptor Tipo 2 de Angiotensina , Especificidade da EspécieRESUMO
There is increasing evidence that angiotensin-(1-7)(Ang-(1-7)) is an endogenous biologically active component of the renin-angiotensin system(RAS). In the present study, we investigated the effects of Ang-(1-7) on reperfusion arrhythmias in isolated rat hearts. Isolated rat hearts were perfused with two different media, i.e., Krebs-Ringer (2.52 mM CaCl2) and low-Ca2+ Krebs-Ringer (1.12 mM CaCl2). In hearts perfused with Krebs-Ringer, Ang-(1-7) produced a concentration-dependent (27-210 nM) reduction in coronary flow (25% reduction at highest concentration), while only slight and variable changes in contraction force and heart rate were observed. Under the same conditions, angiotensin II (Ang II; 27 and 70 nM) produced a significant reduction in coronary flow (39% and 48%, respectively) associated with a significant increase in force. A decrease in heart rate was also observed. In low-Ca2+ Krebs-Ringer solution, perfusion with Ang-(1-7) or Ang II at 27 nM concentration produced similar changes in coronary flow, contraction force and heart rate. In isolated hearts perfused with normal Krebs-Ringer, Ang-(1-7) produced a significant enhancement of reperfusion arrhythmias revealed by an increase in the incidence and duration of ventricular tachycardia and ventricular fibrillation (more than 30-min duration). The facilitation of reperfusion arrhythmias by Ang-(1-7) was associated with an increase in the magnitude of the decreased force usually observed during the postischemic period. The effects of Ang-(1-7) were abolished in isolated rat hearts perfused with low-Ca2+ Krebs-Ringer. The effect of Ang II (27 nM) was similar but less pronounced than that of Ang-(1-7) at the same concentration. These results indicate that the heart is a site of action for Ang-(1-7) and suggest that this heptapeptide may be involved in the mediation of the cardiac effects of the RAS.
Assuntos
Angiotensina II/uso terapêutico , Arritmias Cardíacas/tratamento farmacológico , Frequência Cardíaca/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Reperfusão Miocárdica , Sistema Renina-Angiotensina/fisiologia , Vasoconstritores/uso terapêutico , Animais , Técnicas In Vitro , Masculino , Norepinefrina/farmacologia , Ratos , Ratos WistarRESUMO
There is increasing evidence that angiotensin-(1-7) (Ang-(1-7) is an endogenous biologically active component of the renin-angiotensin system (RAS). In the present study, we investigated the effects of Ang-(1-7) on reperfusion arrhythmias in isolated rat hearts. Isolated rat hearts were perfused with two different media, i.e., Krebs-Ringer (2.52 mM CaCl2) and low-Ca2+ Krebs-Ringer (1.12 mM Cacl2) and low-Ca2+ Krebs-Ringer (1.12 mM CaCl2). In hearts perfused with Krebs-Ringer, Ang-(1-7) produced a concentration-dependent (27-210 nM) reduction in coronary flow (25 percent reduction at highest concentration), while only slight and variable changes in contaction force and heart rate were observed. Under the same conditions, angiotensin II (Ang II; 27 and 70 nM) produced a significant reduction in coronary flow (39 percent and 48 percent, respectively) associated with a significant increase in force. A decrease in heart rate was also observed. In low-Ca2+ Krebs-Ringer solution, perfusion with Ang-(1-7) or Ang II at 27 nM concentration produced similar changes in coronary flow, contraction force and heart rate. In isolated hearts perfused with normal Krebs- Ringer, Ang-(1-7) produced a significant enhancement of reperfusion arrhythmias revealed by an increase in the incidence and duration of ventricular tachycardia and ventricular fibrillation (more than 30-min duration). The faciliation of reperfusion arrhythmias by Ang-(1-7) was associated with an increase in the magnitude of the decreased force usually observed during the postischemic period. The effects of Ang-(1-7) were abolished in isolated rat hearts perfused with low-Ca2+ Krebs-Ringer. The effect of Ang II (27 nM) was similar but less pronounced than that of Ang-(1-7) at the same concentration. These results indicate that the heart is a site of action for Ang-(1-7) and suggest that this heptapeptide may be involved in the mediation of the cardiac effects of the RAS.
Assuntos
Ratos , Animais , Masculino , Angiotensina II/uso terapêutico , Arritmias Cardíacas/tratamento farmacológico , Frequência Cardíaca/efeitos dos fármacos , Técnicas In Vitro , Contração Miocárdica/efeitos dos fármacos , Reperfusão Miocárdica , Norepinefrina/farmacologia , Sistema Renina-Angiotensina/fisiologia , Ratos WistarRESUMO
In this study, the formation of biologically active angiotensins from angiotensin I (Ang I) in isolated rat hearts was evaluated. The role of angiotensin converting enzyme (ACE) in Ang I metabolism was also investigated. HPLC analysis of heart perfusate showed that 125I-Ang I was metabolized extensively (single passage) in the rat coronary circulation in vitro leading to the formation of the biologically active angiotensins: angiotensin II (Ang II), Ang-(2-8), Ang-(3-8) and Ang-(1-7). Ang II was the major product identified in HPLC fractions, corresponding to 7.8 +/- 0.89% of the total radioactivity recovered. A similar profile was observed when single-passage metabolism of non-isotopic Ang I was evaluated by HPLC, followed by radioimmunoassay of the eluate fractions. When 125I-Ang I was perfused in the presence of ACE inhibitors (enalaprilat, ramiprilat) in concentrations up to 130 microM, the formation of Ang II was only partially inhibited (approximately 50%). A similar tendency was observed for Ang-(2-8), Ang-(3-8) and Ang-(2-7). The formation of Ang-(1-7) and its related fragments Ang-(3-7) and Ang-(4-7) was not changed significantly by ACE inhibitors, although a slight increase in formation of these fragments was observed. No significant changes were observed for the carboxyl-terminal fragments of Ang I: Ang-(2-10), Ang-(3-10), and Ang-(4-10). The fractional metabolism of Ang I was not modified by ACE inhibition. These findings suggest that biologically active angiotensins can be formed from Ang I in the rat coronary circulation. These locally generated peptides may contribute to the actions of the renin-angiotensin system in the heart.
Assuntos
Angiotensina I/metabolismo , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Coração/efeitos dos fármacos , Miocárdio/metabolismo , Angiotensina II/metabolismo , Animais , Técnicas In Vitro , Radioisótopos do Iodo , Masculino , Miocárdio/enzimologia , Fragmentos de Peptídeos/metabolismo , Radioimunoensaio , Ratos , Ratos WistarRESUMO
In this study we describe a new angiotensin antagonist [Asp1-Arg2-Val3-Tyr4-Ile5-His6-D-Ala7, (A-779)] selective for the heptapeptide angiotensin-(1-7) [Ang-(1-7)]. A-779 blocked the antidiuretic effect of Ang-(1-7) in water-loaded rats and the changes in blood pressure produced by Ang-(1-7) microinjection into the dorsal-medial and ventrolateral medulla. In contrast, A-779 did not change the dipsogenic, pressor, or myotropic effects of angiotensin II (Ang II). Also, A-779 did not affect the antidiuretic effect of vasopressin or the contractile effects of angiotensin III, bradykinin, or substance P on the rat ileum. In the rostral ventrolateral medulla, the pressor effect produced by Ang-(1-7) microinjection was completely blocked by A-779 but not by AT1 or AT2 receptor antagonists (DUP 753 and CGP 42112A, respectively). Conversely, the pressor effect produced by Ang II was not changed by A-779 but was completely blocked by DUP 753. Binding studies substantiated these observations: A-779 did not compete significantly for 125I-Ang II binding to adrenocortical membranes at up to a 1 microM concentration. Low affinity binding was also observed in adrenomedullary membranes with an IC50 greater than 10 microM. Our results show that A-779 is a potent and selective antagonist for Ang-(1-7). More importantly, our data indicate that specific angiotensin receptors mediate the central and peripheral actions of Ang-(1-7).
Assuntos
Angiotensina II/análogos & derivados , Angiotensina II/antagonistas & inibidores , Fragmentos de Peptídeos/antagonistas & inibidores , Fragmentos de Peptídeos/farmacologia , Receptores de Angiotensina/metabolismo , Glândulas Suprarrenais/efeitos dos fármacos , Glândulas Suprarrenais/metabolismo , Sequência de Aminoácidos , Angiotensina I , Angiotensina II/metabolismo , Angiotensina II/farmacologia , Antagonistas de Receptores de Angiotensina , Animais , Pressão Sanguínea/efeitos dos fármacos , Diurese/efeitos dos fármacos , Feminino , Frequência Cardíaca/efeitos dos fármacos , Técnicas In Vitro , Injeções Intraventriculares , Masculino , Bulbo/efeitos dos fármacos , Dados de Sequência Molecular , Contração Muscular/efeitos dos fármacos , Músculo Liso/efeitos dos fármacos , Músculo Liso/fisiologia , Fragmentos de Peptídeos/metabolismo , Ratos , Ratos Wistar , Receptores de Angiotensina/efeitos dos fármacos , Contração Uterina/efeitos dos fármacosRESUMO
O emprego do AMP (2-amino-2-metil-1-propanol) é proposto como substituto da DEA (Dietanolamina) na determinaçäo de fosfato inorgânico no soro na urina, pelo método direto MCL (Mendes eta al., 1988) Este reagente é mais estável em condiçöes de armazenamento e possui alto poder de solubilizaçäo do precipitado de fosfomolibdato. A análise dos resultados demonstrou uma excelente correlaçäo linear, concluindo que o AMP preenche todos os requisitos necessários para seu emprego na determinacäo de fosfato inorgânico
Assuntos
Indicadores e Reagentes , Fosfatos/sangue , Fosfatos/urina , Propanolaminas/farmacologia , Colorimetria , FotometriaRESUMO
Foram colhidas amostras de sangue de 30 pacientes com tuberculose pulmonar comprovada atraves do encontro do B.A.A.R. em esfregaços de escarro corados pelo Ziehl-Neelsen.. As amostras de sangue foram empregadas, atraves de metodologia adequada, para a determinaçao do perfil hematologico e bioquimico dos tuberculosos em busca de alteraçoes que pudessem ser distribuidas a infeccao. Os resultados observados revelaram uma tendencia a leucocitose (23//dos casos com global acima de 10.000/mm3) e um elevado aumento da velocidade de hemossedimentaçao (86//apresentaram elevaçao com media de 72 a 44 mm para mulheres ehomens, respectivamente). A monocitose, referida por varios autores na tuberculose ativa, nao foi observada. Quanto ao perfil bioquimico, os resultados da determinaçao de fosfatase alcalina e valores obtidos de globulinas se mostraram elevados em 46//dos casos. Esses resultados representaram dados preliminares obtidos atraves das avaliaçoes hematologicas e bioquimicas de pacientes com tuberculose,realizadas antes do emprego da terapeutica recomendada. Estes pacientes representam uma amostragem adequadamente selecionada para a primeira etapa do projeto depesquisa sobre a avaliaçao da conduta farmacoterapeutica no setor publico, com aparticipaçao integrada dos Departamentos de Farmacia Social, Produtos Farmaceuticos e Analises Clinicas e Toxicologicas da Faculdade de Farmacia da UFMG.