RESUMO
This study was conducted to evaluate the effect of medicinal plant by-products (MPB) supplementation to a total mixed ration (TMR) on growth, carcass characteristics and economic efficacy in the late fattening period of Hanwoo steers. Twenty seven steers (body weight [BW], 573±57 kg) were assigned to 3 treatment groups so that each treatment based on BW contained 9 animals. All groups received ad libitum TMR throughout the feeding trial until slaughter (from 24 to 30 months of age) and treatments were as follows: control, 1,000 g/kg TMR; treatment 1 (T1), 970 g/kg TMR and 30 g/kg MPB; treatment 2 (T2), 950 g/kg TMR and 50 g/kg MPB. Initial and final BW were not different among treatments. Resultant data were analyzed using general linear models of SAS. Average daily gain and feed efficiency were higher (p<0.05) for T1 than control, but there was no difference between control and T2. Plasma albumin showed low-, intermediate- and high-level (p<0.05) for control, T1 and T2, whereas non-esterified fatty acid was high-, intermediate- and high-level (p<0.05) for control, T1 and T2, respectively. Carcass weight, carcass rate, backfat thickness and rib eye muscle area were not affected by MPB supplementation, whereas quality and yield grades were highest (p<0.05) for T1 and T2, respectively. Daily feed costs were decreased by 0.5% and 0.8% and carcass prices were increased by 18.1% and 7.6% for T1 and T2 compared to control, resulting from substituting TMR with 30 and 50 g/kg MPB, respectively. In conclusion, the substituting TMR by 30 g/kg MPB may be a potential feed supplement approach to improve economic efficacy in the late fattening period of Hanwoo steers.
RESUMO
In humans, regulatory T (T reg) cells are known to play a critical role in both the regulation of immune homoeostasis and the progression of cancer. However, there is little information about the identification, characterization and the function of T reg cells in canine tumours. We identified T reg cells in 28 canine seminoma samples using a Forkhead box P3 (Foxp3) antibody and investigated the relationship between T reg cell infiltration and histopathological features of classical and spermatocytic seminomas (SE and SS, respectively). The Foxp3 protein showed nuclear immunostaining in infiltrating lymphocytes, and Foxp3+ cells were diffused or focally distributed in seminoma tissues. Foxp3+ cells were frequently present in the SS histotype, in seminomas that showed no evidence of tumour cell invasion into the vessels and in seminomas showing a diffuse growth pattern with three cell types. Neither the SE/SS histotype nor the histopathological features of the tumour correlated with Foxp3+ cell counts. These results indicate that Foxp3+ T reg cells may be associated with a less malignant histological phenotype or may not play a critical role in the immune response of canine seminomas. Moreover, Foxp3+ T reg cells may be associated with SS seminoma, but further studies, involving a larger number of samples, are required to better understand whether these cells play a critical role in the immune response in canine seminomas. This is the first report to demonstrate the characteristics of T reg cell infiltration in canine seminoma.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Doenças do Cão/patologia , Fatores de Transcrição Forkhead/metabolismo , Seminoma/veterinária , Linfócitos T Reguladores/citologia , Neoplasias Testiculares/veterinária , Animais , Proteínas de Ligação a DNA/genética , Cães , Fatores de Transcrição Forkhead/genética , Regulação da Expressão Gênica , Masculino , Seminoma/patologia , Linfócitos T Reguladores/metabolismo , Neoplasias Testiculares/patologiaRESUMO
A modified ludzack ettinger reactor (MLE) combined with a post-denitrification reactor (PDMLE) using electroflotation (EF) as a secondary clarifier was investigated on its feasibility and process performance. Results indicated that higher mixed liquor suspended solids (MLSS) concentrations in bioreactor (5,350 ± 352 mg L(-1)) were maintained via the highly concentrated return sludge (16,771 ± 991 mg L(-1)) from the EF clarifier and the effluent suspended solids (SS) concentrations continued relatively low, representing effluent SS concentration of 1.71 ± 1.16 mg L(-1), compared with GS-A2O process during the operation of four months. The denitrification was improved by combining MLE process with post-denitrification based on endogenous decay (i.e. no additional carbon source was added), resulting in the removal efficiencies of TN were about 91 and 59% for the influent C/N ratio of 10 and 5, respectively, revealing relatively high nitrogen removal as compared with EF-A2O and gravity settling (GS)-A2O processes as a control. The nitrogen balance analysis indicates that pre-denitrification and post-denitrification contributed to 78 and 22% of TN removed, respectively.
Assuntos
Reatores Biológicos/microbiologia , Eletroquímica/métodos , Nitrogênio/metabolismo , Esgotos/microbiologia , Poluentes Químicos da Água/metabolismo , Purificação da Água/métodos , Nitrogênio/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificaçãoRESUMO
The dorsal blastopore lip of the early Xenopus laevis gastrula can organize a complete secondary body axis when transplanted to another embryo. A search for potential gene regulatory components specifically expressed in the organizer was undertaken that resulted in the identification of four types of complementary DNAs from homeobox-containing genes that fulfill this criterion. The most abundant of these encodes a DNA-binding specificity similar to that of the Drosophila melanogaster anterior morphogen bicoid. The other three are also homologous to developmentally significant Drosophila genes. These four genes may participate in the regulation of the developmental potential of the organizer.
Assuntos
Proteínas de Ligação a DNA/fisiologia , Genes Homeobox , Xenopus laevis/embriologia , Xenopus laevis/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , DNA/genética , Indução Embrionária , Expressão Gênica , Biblioteca Gênica , Dados de Sequência Molecular , Morfogênese , Oligonucleotídeos/química , RNA Mensageiro/genéticaRESUMO
In this study, electroflotation (EF) has been applied as a secondary clarification in the activated sludge process to improve the efficiency of the solids-liquid separation, which is essential in maintaining effluent quality. The effects of sludge settleability were examined through a series of batch and semi-continuous experiments. The results of the batch experiments revealed that thickening efficiencies using EF were 2.6 to 9.2 times higher than those with gravity settling (GS). In addition, clarification efficiencies were not significantly influenced by sludge settling properties, as compared with GS as a control. In the semi-continuous EF experiments, the concentrations of solids in the float layer were maintained above 10 g L(-1) during flotation, regardless of variations in sludge settleability. Furthermore, the volumetric gas proportion in the float layer increased as the gas to solids (G/S) ratio rose. This allowed the float layer to be more stably suspended against gravity at the top of the reactor. Based on the results obtained from these batch and semi-continuous experiments, an anoxic/oxic (AO) reactor combined with EF clarifier remained in successful continuous operation for four months. In comparison with conventional AO processes using a GS clarifier, enhanced clarification and thickening efficiencies were achieved through the EF-AO system. In addition, higher mixed liquor suspended solids concentrations (averaging 5300 mg L(-1)) in the bioreactor (EF-AO) were maintained via the return of highly concentrated sludge (averaging 16,400 mg L(-1)) from the EF clarifier. These findings suggest that EF could be a promising and effective alternative for the solids-liquid separation of poorly settling sludge.
Assuntos
Fracionamento Químico/instrumentação , Eletroquímica/instrumentação , Eliminação de Resíduos/instrumentação , Esgotos/química , Purificação da Água/instrumentação , Fracionamento Químico/métodos , Desenho Assistido por Computador , Eletroquímica/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Estudos de Viabilidade , Eliminação de Resíduos/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Esgotos/análise , Purificação da Água/métodosRESUMO
Vertebrate homeodomain proteins are transcription factors whose genes can be isolated via a conserved DNA-binding domain called the homeobox. We review recent studies suggesting that one function of these genes is the early subdivision of the embryo along the antero-posterior axis into 'fields' of cells with different developmental potential.
Assuntos
Genes Homeobox , Fatores de Transcrição/genética , Sequência de Aminoácidos , Animais , Drosophila , Dados de Sequência Molecular , XenopusRESUMO
Bone morphogenetic (BMPs), members of the TGF-beta superfamily, have critical functions in many biological contexts. Recent findings in Drosophila and vertebrates suggest that BMP signaling can be modulated extracellularly and intracellularly by the availability of BMP inhibitors and Smads, respectively.
Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Metaloendopeptidases/metabolismo , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismo , AnimaisRESUMO
Abstract : Despite a longstanding recognition that radiological protection is not only a matter of science, but also ethics, ICRP publications have rarely addressed the ethical foundations of the system of radiological protection explicitly. The purpose of this publication is to describe how the Commission has relied on ethical values, either intentionally or indirectly, in developing the system of radiological protection with the objective of presenting a coherent view of how ethics is part of this system. In so doing, it helps to clarify the inherent value judgements made in achieving the aim of the radiological protection system as underlined by the Commission in Publication 103. Although primarily addressed to the radiological protection community, this publication is also intended to address authorities, operators, workers, medical professionals, patients, the public, and its representatives (e.g. NGOs) acting in the interest of the protection of people and the environment. This publication provides the key steps concerning the scientific, ethical, and practical evolutions of the system of radiological protection since the first ICRP publication in 1928. It then describes the four core ethical values underpinning the present system: beneficence/ non-maleficence, prudence, justice, and dignity. It also discusses how these core ethical values relate to the principles of radiological protection, namely justification, optimisation, and limitation. The publication finally addresses key procedural values that are required for the practical implementation of the system, focusing on accountability, transparency, and inclusiveness. The Commission sees this publication as a founding document to be elaborated further in different situations and circumstances.
Assuntos
Monitoramento de Radiação/ética , Proteção Radiológica/normas , HumanosRESUMO
Euphorbia humifusa Willd. (EH), rich in flavonoids, has long been used for the treatment of bacillary dysentery and enteritis in China, and is known to have antioxidant, hypotensive and hypolipidemic properties. However, the vasorelaxant effect of total flavonoids of EH (TFEH) and action mechanisms are not clearly defined yet. The aim of the present study was to investigate the effects of TFEH on the vascular tension and its underlying mechanisms. Experiments were performed in rat thoracic aorta using the organ bath system. TFEH (0.01 - 100 µg/ml) caused a concentration-dependent vasorelaxation, which was dependent on a functional endothelium, and were significantly attenuated by inhibitors of endothelial NO synthase, its upstream signaling pathway, PI3K/Akt, and soluble guanylate cyclase, but not by blockade of KCa channel, KATP channel, cyclooxygenase, muscarinic and ß-adrenergic receptors. Extracellular Ca2+ depletion, and pre-treatment with modulators of the store-operated Ca2+ entry channels, Gd3+ and 2-aminoethyl diphenylborinate, significantly attenuated the TFEH-induced vasorelaxation. Our findings suggest that TFEH elicit vasorelaxation via endothelium-dependent NO-cGMP pathway through activation of PI3K/Akt- and Ca2+-eNOS-NO signaling. Further, it is suggested that TFEH-induced activation of the NO-soluble guanylate cyclase-cGMP-protein kinase G signaling relaxes vascular smooth muscle cells through an inhibition of the L-type Ca2+ channel activity.
Assuntos
Aorta Torácica/efeitos dos fármacos , Euphorbia/química , Flavonoides/farmacologia , Vasodilatação/efeitos dos fármacos , Vasodilatadores/farmacologia , Animais , Aorta Torácica/metabolismo , Cálcio/metabolismo , Canais de Cálcio/metabolismo , GMP Cíclico/metabolismo , Medicamentos de Ervas Chinesas/farmacologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/metabolismo , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Extratos Vegetais/farmacologia , Prostaglandina-Endoperóxido Sintases/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Guanilil Ciclase Solúvel/metabolismoRESUMO
The International Commission on Radiological Protection (ICRP) has established Task Group 94 under Committee 4 to develop a report on the ethical foundations of the system of radiological protection. The aim of this report is to consolidate the basis of ICRP recommendations, to improve understanding of the system, and to provide a basis for communication on radiation risk and its perception. Through a series of workshops organised by the Commission in cooperation with the International Radiation Protection Association and its associate societies involving radiological protection professionals and specialists of ethics around the world, Task Group 94 has identified the key ethical and social values underpinning the system of radiological protection. The purpose of eliciting the ethical principles and values of the radiological protection system is not only to clarify the rationale for recommendations made by the Commission, but also to assist in discussions related to its practical implementation. A clear understanding of the ethical principles will help resolve dilemmas caused by potential conflicts in actions that might be considered, or decisions that must be made.
Assuntos
Exposição à Radiação/prevenção & controle , Proteção Radiológica/normas , Medição de Risco/ética , Humanos , Agências InternacionaisRESUMO
Detailed in situ analyses reveal overlapping expression of gsc and Xbra in the early Spemann's organizer. Coexpression is lost during gastrulation suggesting an interaction between these genes. Ectopic expression of gsc ventrally suppresses endogenous Xbra expression and transcription from Xbra promoter reporter gene constructs. Suppression is mediated, at least partially, by a gsc-binding site within the first 349 bp of the promoter. Xbra reporter gene transcription is also suppressed in the region of endogenous gsc expression, whereas high-level ectopic Xbra expression has no effect on endogenous gsc expression. We suggest that early patterning of the vertebrate mesoderm, like early patterning of the Drosophila embryo, occurs by first establishing broad domains of gene expression which are subsequently refined by intergenic interactions to further delimit tissue boundaries.
Assuntos
Proteínas de Ligação a DNA/genética , Proteínas Fetais/genética , Regulação da Expressão Gênica no Desenvolvimento , Proteínas de Homeodomínio , Proteínas Repressoras , Proteínas com Domínio T , Xenopus laevis/embriologia , Xenopus laevis/genética , Animais , Sequência de Bases , Proteína Goosecoid , Mesoderma , Dados de Sequência Molecular , Fatores de Transcrição/genéticaRESUMO
Rumex acetosa L. (RA) (Polygonaceae) is an important traditional Chinese medicine (TCM) commonly used in clinic for a long history in China and the aerial parts of RA has a wide variety of pharmacological actions such as diuretic, anti-hypertensive, anti-oxidative, and anti-cancer effects. However, the mechanisms involved are to be defined. The purpose of the present study was to evaluate the vasorelaxant effect and define the mechanism of action of the ethanol extract of Rumex acetosa L. (ERA) in rat aorta. ERA was examined for its vascular relaxant effect in isolated phenylephrine-precontracted rat thoracic aorta and its acute effects on arterial blood pressure. In addition, the roles of the nitric oxide synthase (NOS)-nitric oxide (NO) signaling in the ERA-induced effects were tested in human umbilical vein endothelial cells (HUVECs). The phosphorylation levels of Akt and eNOS were assessed by Western blot analysis in the cultured HUVECs. ERA induced endothelium-dependent vasorelaxation. The ERA-induced vasorelaxation was abolished by L-NAME (an NOS inhibitor) or ODQ (a sGC inhibitor), but not by indomethacin. Inhibition of PI3-kinase/Akt signaling pathway markedly reduced the ERA-induced vasorelaxation. In HUVECs, ERA increased NO formation in a dose-dependent manner, which was inhibited by L-NAME and by removing extracellular Ca(2+). In addition, ERA promoted phosphorylation of Akt and eNOS, which was prevented by wortmannin and LY294002, indicating that ERA induces eNOS phosphorylation through the PI3-kinase/Akt pathway. Further, in anesthetized rats, intravenously administered ERA decreased arterial blood pressure in a dose-dependent manner through an activation of the NOS-NO system. In summary, the ERA- induced vasorelaxation was dependent on endothelial integrity and NO production, and was mediated by activation of both the endothelial PI3-kinase/Akt- and Ca(2+)-eNOS-NO signaling and muscular NO-sGC-cGMP signaling.
Assuntos
Aorta/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Extratos Vegetais/farmacologia , Rumex , Vasodilatadores/farmacologia , Animais , Aorta/fisiologia , Cálcio/metabolismo , Células Cultivadas , GMP Cíclico/metabolismo , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Técnicas In Vitro , Masculino , Medicina Tradicional Chinesa , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo III/metabolismo , Fosfatidilinositol 3-Quinase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Vasodilatação/efeitos dos fármacosRESUMO
The positive roles of the Wnt/ß-catenin pathway in osteoblast differentiation and bone mineral density (BMD) maintenance have been clearly demonstrated in both animal experiments and clinical investigations. CXXC finger protein 5 (CXXC5), a recently identified negative regulator of the Wnt/ß-catenin pathway, showed altered cellular localization and function, which were dependent on the cell type in previous studies. However, the in vivo function of CXXC5 has not been clearly investigated yet. Here, we characterized CXXC5 as a negative regulator of osteoblast differentiation and bone formation. Deficiency of CXXC5 resulted in elevated BMD in mice without any severe gross developmental abnormalities. CXXC5 exerted a negative-feedback effect on the Wnt/ß-catenin pathway via Wnt-dependent binding to Dishevelled (Dvl) during osteoblast differentiation. Suppression of the Dvl-CXXC5 interaction using a competitor peptide resulted in the activation of the Wnt/ß-catenin pathway and osteoblast differentiation, and accelerated thickness growth of ex vivo-cultured calvariae. Overall, CXXC5 is a negative-feedback regulator induced by Wnt/ß-catenin signaling that inhibits osteoblast differentiation and bone formation via interaction with Dvl.
Assuntos
Osteoblastos/citologia , Osteoblastos/metabolismo , Receptores CXCR5/metabolismo , Via de Sinalização Wnt/fisiologia , beta Catenina/metabolismo , Animais , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Linhagem Celular , Humanos , Camundongos , Camundongos Knockout , Receptores CXCR5/genética , Proteínas Wnt/genética , Proteínas Wnt/metabolismoRESUMO
The atrial natriuretic peptide (ANP) gene is expressed in several extraatrial tissues in which ANP may be involved in the regulation of autocrine or paracrine functions. In the ovary, the synthesis of ANP, its binding sites, and a physiological role were found. The ANP system in the oviduct, however, is yet to be defined. The purpose of the present study was to determine whether the ANP system is present in the oviduct and then to define its function. The serial dilution curves of oviductal extracts in rat and rabbit were parallel to the standard curve of ANP. Molecular profiles using reverse phase HPLC indicated that the prohormone and processed circulating peptide were the main forms present. The immunoreactive ANP content of the oviduct was 27.07 +/- 4.41 pg/mg tissue wet wt (1.19 +/- 0.19 ng/oviduct; n = 10; at metestrus) in rats and 1.21 +/- 0.12 pg/mg tissue wet wt (0.15 +/- 0.01 ng/oviduct; n 12) in rabbits. In adult 4-day cycling rats, the immunoreactive ANP contents in oviducts had a cyclic change characterized by the lowest level at proestrus (14.59 +/- 3.24 pg/mg; n = 12). A distinct and strong ANP immunoreactivity was found in the mucosal layer of rat oviduct, and ANP messenger RNA was also detected in the oviduct by reverse transcriptase-PCR. Specific high affinity binding sites for iodinated rat ANP ([125I]rANP) were observed in the mucosal layer of the oviduct in rats and rabbits. Specific [125I]rANP bindings localized in the mucosal layer of rabbit oviduct showed an apparent dissociation constant (Kd) of 18.69 +/- 5.55 nM and a maximal binding capacity of 14.85 +/- 6.19 fmol/mm2. These specific [125I]rANP bindings were not reversed by des-[Gln18,Ser19,Gly20,Leu21,Gly22]ANP-(4- 23) as a selective ligand of clearance receptor. Synthetic ANP inhibited both the frequency and amplitude of basal motility of rabbit oviduct in a dose-dependent manner. These results suggest that the oviduct has its own ANP system, and the system is involved in the regulation of oviductal motility.
Assuntos
Fator Natriurético Atrial/análise , Fator Natriurético Atrial/biossíntese , Tubas Uterinas/fisiologia , Receptores do Fator Natriurético Atrial/metabolismo , Animais , Cromatografia Líquida de Alta Pressão , Estro , Tubas Uterinas/química , Tubas Uterinas/citologia , Feminino , Imuno-Histoquímica , Mucosa/química , Mucosa/citologia , Mucosa/fisiologia , Contração Muscular , Músculo Liso/fisiologia , Fragmentos de Peptídeos , Reação em Cadeia da Polimerase , RNA Mensageiro/biossíntese , Coelhos , Ratos , Ratos Sprague-Dawley , Receptores do Fator Natriurético Atrial/análiseRESUMO
For investigation of the relation of cell cycle regulation with tumorigenesis in cats, we carried out molecular cloning of feline p21WAF1 and p27Kip1 cDNAs and chromosomal mapping of these genes on the cat genome. The feline p21WAF1 cDNA clone obtained in this study encoded 164 amino acids (aa) showing 83.5% and 76.8% sequence similarity with those of the human and mouse counterparts, respectively. The cat p27Kip1 cDNA clone isolated here encoded 198 aa, showing sequence similarities of 93.4% and 90.4% with its human and mouse counterparts, respectively. Using a panel of feline x rodent somatic cell hybrids, the feline CDKN1A (p21WAF1) and CDKN1B (p27Kip1) loci were assigned to feline chromosomes B2 and B4, respectively. Southern-blot analyses of 17 feline spontaneous leukemia and lymphoma cases using these cDNAs as probes did not reveal any rearrangements in either the p21WAF1 or the p27Kip1 gene. RT-PCR/SSCP (single strand conformation polymorphism) analysis of p27Kip1 cDNA did not uncover any amino acid substitutions in the 10 feline leukemia and lymphoma cases that were examined.
Assuntos
Gatos/genética , Proteínas de Ciclo Celular , Ciclinas/genética , Proteínas Associadas aos Microtúbulos/genética , Proteínas Supressoras de Tumor , Sequência de Aminoácidos , Animais , Doenças do Gato/genética , Mapeamento Cromossômico , Clonagem Molecular , Inibidor de Quinase Dependente de Ciclina p21 , Inibidor de Quinase Dependente de Ciclina p27 , DNA Complementar/genética , Humanos , Leucemia/genética , Leucemia/veterinária , Linfoma/genética , Linfoma/veterinária , Camundongos , Dados de Sequência Molecular , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
A new technique to permit gradual changes in atrial distension has been developed in an isolated perfused rabbit atrium preparation. Graded volume reduction in the atrium was induced by changing the elevation of the outflow catheter tip. Pressure reduction from 6 cm H2O atrial distension resulted in a decrease in atrial distension volume. Atrial distension by 6 cmH2O did not change the release of immunoreactive atrial natriuretic peptide (irANP). The graded reduction in atrial distension from 0.11 +/- 0.03 (1.5 cm H2O) to 1.36 +/- 0.19 microliters/mg wet weight (6.0 cm H2O) resulted in 1.7 (6.76 +/- 2.05 versus 3.83 +/- 1.18 pg/mg per min, n = 9, P less than 0.025) to 40.1-fold (77.66 +/- 17.82 versus 3.0 +/- 1.14 pg/mg per min, n = 11, P less than 0.025) increases in irANP release. IrANP release in response to the reduction of atrial distension was volume dependent. The relation of percentage increase in irANP release with the percentage reduction of atrial distension was exponential. The data suggest that the atrial muscle shortening, but not stretch per se, may be a potent direct stimulus for the regulation of irANP secretion.
Assuntos
Função Atrial , Fator Natriurético Atrial/metabolismo , Volume Cardíaco , Animais , Átrios do Coração/metabolismo , Técnicas In Vitro , Perfusão , Pressão , CoelhosRESUMO
PURPOSE: To determine whether the cornea synthesizes natriuretic peptides and contains their receptors. METHODS: The synthesis of the natriuretic peptides, C-type natriuretic peptide (CNP) and atrial natriuretic peptide (ANP), in the bovine cornea was determined by high-performance liquid chromatography (HPLC) with radioimmunoassay and Southern blot analysis. The presence of natriuretic peptide receptor (NPR)-A and -B and their localizations were measured by reverse transcription-polymerase chain reaction (RT-PCR), in vitro autoradiography, and the activation of particulate guanylyl cyclase by natriuretic peptides in the corneal membrane. RESULTS: The serial dilution curves of corneal extracts were parallel to the standard curves of CNP and ANP. With reversed-phase HPLC, a major immunoreactive peak of CNP or ANP was observed at the elution time corresponding with synthetic CNP(1-53) or atriopeptin III (APIII), respectively. The presence of mRNAs of CNP and ANP was also detected in the cornea by RT-PCR and/or Southern blot analysis. Production of 3',5'-cyclic guanosine monophosphate (cGMP) by the activation of particulate guanylyl cyclase in the corneal membrane was stimulated by ANP, BNP, and CNP. More cGMP was produced by CNP than by the other natriuretic peptides. Specific 125I-[Tyr0]-CNP(1-22) binding sites were localized in the endothelial cell layer of cornea. The apparent dissociation constant (Kd) value of the cornea was 3.06 +/- 0.73 nM and the maximum binding capacity was 3.40 +/- 0.63 femtomoles/mm2. Both NPR-A and NPR-B mRNAs were detected by RT-PCR. CONCLUSIONS: The cornea synthesizes CNP and ANP and contains their receptors. These results suggest that the CNP and ANP systems coexist in the bovine cornea.
Assuntos
Fator Natriurético Atrial/análise , Córnea/química , Peptídeo Natriurético Tipo C/análise , Animais , Fator Natriurético Atrial/biossíntese , Fator Natriurético Atrial/genética , Autorradiografia , Southern Blotting , Bovinos , Cromatografia Líquida de Alta Pressão , Córnea/metabolismo , GMP Cíclico/biossíntese , Primers do DNA/química , Eletroforese em Gel de Ágar , Guanilato Ciclase/genética , Guanilato Ciclase/metabolismo , Peptídeo Natriurético Tipo C/biossíntese , Peptídeo Natriurético Tipo C/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/metabolismo , Radioimunoensaio , Receptores do Fator Natriurético Atrial/genética , Receptores do Fator Natriurético Atrial/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
C-type natriuretic peptide (CNP) is mainly distributed in the brain and vascular endothelium and is considered to act as a local regulator in many tissues. The present study was aimed to determine the presence of CNP system and its biological function in rabbit colon. The serial dilution curves of tissue extracts were parallel to the standard curve of CNP-22. With gel permeation chromatography and reverse-phase HPLC, the major immunoreactive peak of CNP was observed at the same elution time corresponding to the synthetic CNP-53. The concentration of CNP in the mucosal layer of colon was 212.49 +/- 30.44 pg/g tissue wet weight (n = 7), which was significantly higher than that in the muscular layer. The presence of CNP mRNA was also detected by RT-PCR and Southern blot analysis. Production of cGMP by the activation of particulate guanylyl cyclase stimulated by BNP and CNP was higher in membranes obtained from the muscular layer than from mucosal layer. More cGMP was produced by CNP than by ANP. Both natriuretic peptide receptor-A and -B mRNAs were detected by RT-PCR and specific binding sites to 125I-[Tyr(0)]-CNP-22 were mainly localized to the muscular layer. Synthetic CNP inhibited basal tension, frequency and amplitude of basal motility of taenia coli of the right colon. This study showing the presence of CNP system and its biological function in colon suggests that endogenous CNP synthesized in the mucosal layer may have a paracrine function as a local regulator of colonic motility.
Assuntos
Colo/metabolismo , Peptídeo Natriurético Tipo C/metabolismo , Animais , Autorradiografia , Sequência de Bases , Southern Blotting , Colo/fisiologia , Primers do DNA , Técnicas In Vitro , Peptídeo Natriurético Tipo C/fisiologia , Coelhos , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
C-type natriuretic peptide (CNP), a third member of the natriuretic peptide family, is known to be distributed mainly in brain and vascular endothelium and is considered to act as a local regulator in many tissues. The purpose of this study was to determine the presence of CNP system and its biological function in rabbit oviduct. The serial dilution curve of tissue extracts was parallel to the standard curve of CNP((1-22)) and a major peak of molecular profile of tissue extracts by HPLC was CNP((1-53)). mRNA of CNP which was the same size as positive control was also detected by Southern blot analysis. CNP increased the production of 3',5'-cyclic guanosine monophosphate (cGMP) in the purified membrane of oviduct, which was more in membranes derived from the isthmic portion than in the ampullar portion. The presence of mRNAs of natriuretic peptide receptor-A (NPR-A) and NPR-B was demonstrated by RT-PCR. Synthetic CNP((1-22)) inhibited both frequency and amplitude of basal motility of oviduct in a dose-dependent manner. The inhibitory effect of CNP on the basal motility was more potent in the isthmic portion than in the ampullar portion. These results demonstrate the presence of CNP system in the oviduct and regional differences in motility inhibition by CNP between isthmic and ampullar portions. Therefore, these findings suggest the possible existence of a CNP system that may exert a local regulator of basal motility, either alone or in concert with other hormones.
Assuntos
Peptídeo Natriurético Tipo C/metabolismo , Oviductos/metabolismo , Animais , Southern Blotting , Membrana Celular/metabolismo , Cromatografia Líquida de Alta Pressão , GMP Cíclico/metabolismo , Relação Dose-Resposta a Droga , Feminino , RNA Mensageiro/metabolismo , Coelhos , Radioimunoensaio , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
In order to investigate the regulatory mechanism for the atrial release of atrial natriuretic peptide (ANP), a perfused rabbit atrial model was devised. In the present experiments, the effect of a reduction in atrial distension on the immunoreactive ANP (irANP) secretion was investigated and compared in the perfused right and left atria of rats. Elevations in right and left atrial pressure resulted in proportional increases in the volume of atrial distension-reduction which was larger in the right than in the left atria. The basal rate of irANP secretion was higher in the right than in the left atria. Increases in the volume of atrial distension-reduction resulted in proportional increases in irANP secretion in both atria. Increment in irANP secretion in response to a reduction in atrial distension was significantly higher in the right than in the left atria. Higher rate of irANP secretion in response to unit volume change was observed in the right atria. Increases in the volume of atrial distension-reduction resulted in accentuated irANP responses in the right atrium. IrANP content was significantly higher in the right than in the left atria. The results suggest that the right atrium is a predominant site in ANP secretion in rats.