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1.
BMC Med Educ ; 24(1): 135, 2024 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-38347571

RESUMO

BACKGROUND: The swift transition to online teaching in medical education has presented the challenge of replicating in-class engagement and interaction essential for active learning. Despite online team-based learning (TBL) offering potential solutions through structured cooperative activities, its efficacy in virtual simulation experiment courses remains scantily researched. This study investigates the effectiveness of online TBL for teaching virtual patient experiments in a basic medical laboratory course and contrasts it with traditional offline teaching in terms of student performance and perceptions. METHODS: A comparative analysis involved 179 Year 3 medical students using online TBL, face-to-face TBL (FTF-TBL), and the flipped classroom (FC) approach. The learning outcomes were assessed based on experiment reports, IRAT scores, TRAT scores, and final exam performance. Students' perceptions of both online and in-class TBL methodologies were also surveyed. RESULTS: Both online and in-class TBL groups demonstrated comparable academic outcomes and surpassed the FC group in academic performance. Students displayed a marked preference for the TBL format (whether online or in-class), valuing its enhancement of learning interest and practical knowledge application. Nevertheless, refinements in discussion efficiency, platform convenience, and student-instructor interaction were indicated as potential areas of improvement in the online setting. CONCLUSIONS: Online TBL, along with its in-class counterpart, showed superior academic performance and a more positive learning experience compared to the FC group. These findings underscore the potential of online TBL in adapting to modern pedagogical challenges and enriching medical education through virtual simulation experiments.


Assuntos
Educação Médica , Estudantes de Medicina , Humanos , Avaliação Educacional , Aprendizagem Baseada em Problemas/métodos , Currículo
2.
BMC Med Educ ; 22(1): 608, 2022 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-35933354

RESUMO

BACKGROUND: Basic medical laboratory courses (BMLCs) play an essential role in medical education and offer several benefits to students. Although various student-centered and active learning strategies have been increasingly incorporated into medical education, their applications in BMLCs are limited. This paper aimed to explore the educational effects of a flipped classroom (FC) combined with team-based learning (TBL) strategy in BMLCs at Zhejiang University School of Medicine. METHODS: Four hundred eight 3rd-Year medical students were assigned to either the FC-TBL group (n = 235) or the FC group (n = 173) to complete three experiments on the respiration block of BMLCs. The two groups' immediate and long-term academic performance were compared, and the FC-TBL students' perceptions of different instructional strategies were surveyed. RESULTS: Students in the FC-TBL group scored higher on the immediate post-tests after class and higher on the final exams in two of the three experiment sessions. They preferred FC-TBL to FC for its higher engagement, more feedback, and better learning environment. Students felt the FC with TBL blended instructional strategy stimulated their interest in learning and deep thinking. CONCLUSIONS: Compared with the FC group, students in the FC-TBL group improved academic performance and had a more positive experience overall. Our findings support the feasibility and advantage of the flipped classroom with team-based learning as a blended learning strategy in the BMLC curriculum.


Assuntos
Educação Médica , Estudantes de Medicina , Currículo , Avaliação Educacional , Humanos , Aprendizagem Baseada em Problemas
3.
J Ethnopharmacol ; 259: 112883, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32315736

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Rhodiola has been used to treat cough, hemoptysis, fever, pain, bruise and other symptoms which are related to injury and inflammation over a thousand years in traditional Tibetan medicine. Salidroside (p-hydroxyphenethyl-ß-D-glucoside) is one of the most potent bioactive ingredients of the genus Rhodiola. AIM OF STUDY: The present study aimed to explore whether salidroside could alleviate the clinical symptom and sign in the early acute stage of osteoarthritis (OA) in monosodium iodoacetate (MIA) rat model, and its underlying mechanisms. MATERIALS AND METHODS: Osteoarthritis (OA) was induced in rat knees by intra-articular injection of MIA; simultaneously salidroside was administered by intravenous injection. Pain behaviors were evaluated by knee-bend test, hind limb weight-bearing asymmetry and hind paw mechanical withdrawal threshold. The joint swelling was determined by the difference of knee joint diameter. Inflammatory exudates in synovial fluid were evaluated by leukocyte counting and protein content. Cytokines, chemokines, reactive oxygen species (ROS) and reactive nitrogen species (RNS) markers were determined by Enzyme-linked immunosorbent assay (ELISA) and colorimetric assay in synovial fluid. Pro-inflammatory gene expressions in synovial tissue were detected by quantitative real time RT-PCR (qRT-PCR). Nuclear factor kappa-B (NF-κB) DNA binding assay and western blot were used to determine NF-κB activation and ROS marker protein expression in synovial tissue. Glycosaminoglycan (GAG) content in the cartilage was measured by dimethylmethylene blue method. Hematoxylin and eosin (H&E), Safranin O-fast green and a modified Mankin grading system were used to evaluate the histology of articular cartilage. RESULTS: Salidroside could alleviate pain and joint swelling in the early acute stage of OA in rat model, reduced the number of leukocytes, total protein content, proinflammatory mediators and ROS/RNS markers in synovial fluid, down regulated the expression of proinflammatory genes in synovium, inhibited the activation of NF- κ B and oxidative stress response in synovium, promoted the synthesis of cartilage GAG, prevented the loss of proteoglycan and chondrocyte degeneration. CONCLUSIONS: Salidroside effectively alleviates acute symptom and sign of OA in rat model by its anti-inflammatory and antioxidant affects to inhibit synovial inflammation, which provides a new strategy to prevent the onset and progression of OA.


Assuntos
Anti-Inflamatórios/farmacologia , Glucosídeos/farmacologia , Osteoartrite/tratamento farmacológico , Fenóis/farmacologia , Animais , Antioxidantes/farmacologia , Cartilagem Articular/efeitos dos fármacos , Cartilagem Articular/patologia , Condrócitos/efeitos dos fármacos , Citocinas/metabolismo , Feminino , Inflamação/tratamento farmacológico , Injeções Intravenosas , Ácido Iodoacético , Articulação do Joelho/patologia , Osteoartrite/induzido quimicamente , Dor/tratamento farmacológico , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Líquido Sinovial/efeitos dos fármacos , Líquido Sinovial/metabolismo , Membrana Sinovial/efeitos dos fármacos , Membrana Sinovial/metabolismo
4.
Sheng Li Xue Bao ; 71(4): 575-580, 2019 Aug 25.
Artigo em Chinês | MEDLINE | ID: mdl-31440754

RESUMO

The aim of the present study was to investigate the effect of salidroside (Sal) on inflammatory activation induced by lipopolysaccharide (LPS) in the co-culture of rat alveolar macrophages (AM) NR 8383 and type II alveolar epithelial cells (AEC II) RLE-6TN. CCK-8 colorimetric method was used to detect cell proliferation percentage. The enzyme-linked immunosorbent assay (ELISA) was used to determine the content of tumor necrosis factor alpha (TNF-α), macrophage inflammatory protein-2 (MIP-2) and interleukin-10 (IL-10) in the supernatant. Western blot was used to examine the expression levels of phosphorylated AKT (p-AKT) and total AKT protein. The results showed that pretreatment of RLE-6TN cells or co-culture of RLE-6TN and NR 8383 cells with 32 and 128 µg/mL Sal for 1 h, followed by continuous culture for 24 h, significantly increased the cell proliferation (P < 0.05). Compared with control group, 32 and 128 µg/mL Sal pretreatment significantly increased the ratio of p-AKT/AKT in RLE-6TN cells (P < 0.05). Pretreatment of 32 µg/mL Sal not only inhibited the secretion of TNF-α and MIP-2 by NR 8383 cells induced by LPS (P < 0.05), but also enhanced the inhibitory effect of RLE-6TN and NR 8383 cells co-culture on the secretion of TNF-α and MIP-2 by NR 8383 cells induced by LPS (P < 0.05). In addition, 32 µg/mL Sal pretreatment promoted LPS-induced IL-10 secretion by NR 8383 cells (P < 0.05), and enhanced the promoting effect of co-culture of RLE-6TN and NR 8383 cells on the IL-10 secretion by LPS-induced NR 8383 cells (P < 0.05). In conclusion, Sal may directly inhibit LPS-induced inflammatory activation of AM (NR 8383), promote the proliferation of AEC II (RLE-6TN) through PI3K/AKT signaling pathway, and enhance the regulatory effect of AEC II on LPS-induced inflammatory activation of AM.


Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Glucosídeos/farmacologia , Macrófagos Alveolares/efeitos dos fármacos , Fenóis/farmacologia , Transdução de Sinais , Células Epiteliais Alveolares/metabolismo , Animais , Linhagem Celular , Quimiocina CXCL2/metabolismo , Técnicas de Cocultura , Interleucina-10/metabolismo , Lipopolissacarídeos , Macrófagos Alveolares/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Fator de Necrose Tumoral alfa/metabolismo
5.
Sheng Li Xue Bao ; 69(3): 291-297, 2017 Jun 25.
Artigo em Chinês | MEDLINE | ID: mdl-28638921

RESUMO

To study the protective effect and mechanism of synthetic salidroside on acute lung injury (ALI) induced by lipopolysaccharide (LPS), male Sprague-Dawley (SD) rats were randomly divided into saline control group, 3 mg/kg LPS model group, different doses of salidroside groups (5, 20 and 80 mg/kg), and 5 mg/kg dexamethasone group. Intratracheal LPS instillation was used to establish the ALI model 0.5 h after intraperitoneal injection of salidroside or dexamethasone, and the rats were sacrificed 6 h later. Lung wet/dry weight ratio (W/D) was calculated. Lung tissue pathology and lung injury score (LIS) were observed and evaluated through hematoxylin and eosin (HE) staining. The centrifugal sediment of bronchoalveolar lavage fluid (BALF) was used to count the polymorphonuclear leukocyte (PMN) number by Wright's staining, and the centrifugal supernatant of BALF was used to determine the contents of protein and inflammatory factors (TNF-α, IL-1ß and IL-6). The contents of myeloperoxidase (MPO) and malondialdehyde (MDA) in lung tissue were determined. Western blot was used to detect the expression levels of phosphorylated and total nuclear factor kappa B (NF-κB)/p65 protein in lung tissue. The results showed that, compared with LPS group, the intervention of synthetic salidroside alleviated the pathological damage in lung tissue, decreased the LIS and lung W/D ratio (P < 0.05), reduced the PMN number, the contents of protein and inflammatory factors in BALF (P < 0.05), reduced the contents of MPO and MDA in lung tissue (P < 0.05), and inhibited the expression of p-NF-κB in lung tissue (P < 0.05). The results suggest that synthetic salidroside has a protective effect on ALI induced by LPS, and its mechanism is related to inhibiting the phosphorylation of NF-κB and reducing the aggregation of PMN in the lung.


Assuntos
Lesão Pulmonar Aguda/tratamento farmacológico , Glucosídeos/farmacologia , Neutrófilos/citologia , Fenóis/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Animais , Líquido da Lavagem Broncoalveolar , Dexametasona/farmacologia , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos , Pulmão/efeitos dos fármacos , Pulmão/patologia , Masculino , Malondialdeído/metabolismo , NF-kappa B/metabolismo , Peroxidase/metabolismo , Fosforilação , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley
6.
Mol Ther Nucleic Acids ; 5: e299, 2016 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-27003758

RESUMO

Epidermolytic palmoplantar keratoderma (EPPK) is a relatively common autosomal-dominant skin disorder caused by mutations in the keratin 9 gene (KRT9), with few therapeutic options for the affected so far. Here, we report a knock-in transgenic mouse model that carried a small insertion-deletion (indel) mutant of Krt9, c.434delAinsGGCT (p.Tyr144delinsTrpLeu), corresponding to the human mutation KRT9/c.500delAinsGGCT (p.Tyr167delinsTrpLeu), which resulted in a human EPPK-like phenotype in the weight-stress areas of the fore- and hind-paws of both Krt9(+/mut) and Krt9(mut/mut) mice. The phenotype confirmed that EPPK is a dominant-negative condition, such that mice heterozygotic for the K9-mutant allele (Krt9(+/mut)) showed a clear EPPK-like phenotype. Then, we developed a mutant-specific short hairpin RNA (shRNA) therapy for EPPK mice. Mutant-specific shRNAs were systematically identified in vitro using a luciferase reporter gene assay and delivered into Krt9(+/mut) mice. shRNA-mediated knockdown of mutant protein resulted in almost normal morphology and functions of the skin, whereas the same shRNA had a negligible effect in wild-type K9 mice. Our results suggest that EPPK can be treated by gene therapy, and this has significant implications for future clinical application.

7.
Sheng Li Xue Bao ; 64(6): 651-6, 2012 Dec 25.
Artigo em Chinês | MEDLINE | ID: mdl-23258328

RESUMO

The present study aims to explore the possible mechanisms that trichostatin A (TSA), a histone deacetylases inhibitor (HDACi), affects the inflammatory signaling pathways of lipopolysaccharide/toll-like receptor 4/nuclear factor-κB (LPS/TLR4/NF-κB). Murine macrophage cell line RAW264.7 cells were employed. MTT assay was used to assess cell viability. The contents of TNF-α, IL-1ß and IL-6 in culture supernatant were assayed by enzyme-linked immunosorbent assay (ELISA). TLR4 expression and NF-κB/p65 (Lys310) acetylation were examined by Western blotting. DNA binding activity of NF-κB/p65 was detected by using TransAM(TM) NF-κB/p65 activity assay kit. The results showed that, compared with control group, which was treated by DMSO, the cells treated with TSA (20, 40, 80 ng/mL) showed decreased percentages of cell survival (P < 0.05). The contents of TNF-α, IL-1ß and IL-6 in culture supernatant were all increased by LPS (100 ng/mL), whereas reduced by 40 ng/mL TSA pretreatment (P < 0.05). TSA pretreatment inhibited LPS-induced up-regulation of TLR4 protein expression. Acetylation of NF-κB/p65(Lys310), which was already increased by LPS, was further enhanced by TSA (P < 0.05). On the contrary, LPS-increased DNA binding activity of NF-κB/p65 was decreased by pretreatment with TSA (P < 0.05). The results suggest that TSA-induced anti-inflammation may be attributed to decreases in the expression of TLR4 and DNA binding activity of NF-κB/p65.


Assuntos
Ácidos Hidroxâmicos/farmacologia , Macrófagos/efeitos dos fármacos , Receptor 4 Toll-Like/metabolismo , Fator de Transcrição RelA/metabolismo , Acetilação , Animais , Linhagem Celular , Inflamação/metabolismo , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Lipopolissacarídeos , Macrófagos/metabolismo , Camundongos , Transdução de Sinais , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Cima
8.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 41(2): 166-70, 2012 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-22499513

RESUMO

OBJECTIVE: To compare the effects of mannitol and hypertonic saline (HS) in treatment of intracranial hypertension (ICH) of rabbits. METHODS: The animal mode of ICH was established by perfusing artificial cerebrospinal fluids (aCSF) with controlled pressure into the cerebral ventricles of rabbits. The mean arterial pressure, respiratory rate, tidal volume, perfusion rate of aCSF and water content of cerebrum were investigated in rabbits with ICH after a single bolus of 20% mannitol (5 ml/kg), 7.5% HS (2.2 ml/kg) or 23.4% HS (2.2 ml/kg). RESULTS: After the intracranial pressure was elevated from 15 cmH2O to 75 cmH2O, the mean arterial pressure was increased and the tidal volume was decreased. After treatment by 20% mannitol, 7.5% HS or 23.4% HS, the increased percentage of mean arterial pressure and the decreased percentage of tidal volume were similar to the changes in control group. However, the perfusion rate of CSF was increased and water content of cerebrum was decreased after treatment by either 20% mannitol or 23.4% HS, but not by 7.5% HS. No different effects were found between 20% mannitol and 23.4% HS. CONCLUSION: With the similar osmotic burden, 20% mannitol is more effective in treating ICH than 7.5% HS. With higher osmotic load, the efficacy of HS is enhanced, and 23.4% HS may be used as an alternative to mannitol in treatment of ICH.


Assuntos
Hipertensão Intracraniana/tratamento farmacológico , Manitol/uso terapêutico , Solução Salina Hipertônica/uso terapêutico , Animais , Modelos Animais de Doenças , Feminino , Masculino , Manitol/administração & dosagem , Coelhos , Solução Salina Hipertônica/administração & dosagem
9.
Cell Biol Toxicol ; 26(6): 499-507, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20309622

RESUMO

Salidroside (p-hydroxyphenethyl-beta-d-glucoside), which is present in all species of the genus Rhodiola, has been reported to have a broad spectrum of pharmacological properties. The present study, for the first time, focused on evaluating the effects of the purified salidroside on the proliferation of various human cancer cell lines derived from different tissues, and further investigating its possible molecular mechanisms. Cell viability assay and [(3)H] thymidine incorporation were used to evaluate the cytotoxic effects of salidroside on cancer cell lines, and flow cytometry analyzed the change of cell cycle distribution induced by salidroside. Western immunoblotting further studied the expression changes of cyclins (cyclin D1 and cyclin B1), cyclin-dependent kinases (CDK4 and Cdc2), and cyclin-dependent kinase inhibitors (p21(Cip1) and p27(Kip1)). The results showed that salidroside inhibited the growth of various human cancer cell lines in concentration- and time-dependent manners, and the sensitivity to salidroside was different in those cancer cell lines. Salidroside could cause G1-phase or G2-phase arrest in different cancer cell lines, meanwhile, salidroside resulted in a decrease of CDK4, cyclin D1, cyclin B1 and Cdc2, and upregulated the levels of p27(Kip1) and p21(Cip1). Taken together, salidroside could inhibit the growth of cancer cells by modulating CDK4-cyclin D1 pathway for G1-phase arrest and/or modulating the Cdc2-cyclin B1 pathway for G2-phase arrest.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Glucosídeos/farmacologia , Fenóis/farmacologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/genética , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Expressão Gênica/efeitos dos fármacos , Humanos
10.
Environ Toxicol Pharmacol ; 29(1): 79-86, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21787586

RESUMO

Human Pol ι is a highly distributed, low-fidelity DNA polymerase lacking intrinsic exonuclease proofreading activity, thus its effects are strictly regulated. We predicted and cloned the promoter region of the human POLI gene. Successively, by transfection of deletion constructs of the POLI promoter, we demonstrated that the regions -848/-408 and -30/+215 contained positive regulatory elements, and the region +215/+335 had proximal promoter activity. Overexpression of Sp1 significantly increased the transcriptional activity of the promoter, and mutation of the Sp1 site reversed Sp1-induced promoter transactivation. Quantitative RT-PCR showed that POLI mRNA expression was up-regulated in human amnion FL cells treated by the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Reporter gene assays demonstrated that MNNG also significantly increased the transcriptional activity of the predicted promoter (-848/+335) and the proximal promoter (+215/+335). However, the promoter with the Sp1 site mutation had no response to MNNG treatment, suggesting that Sp1 plays an important role in the transcriptional regulation of the POLI gene stimulated by MNNG. Our data suggest that abnormal regulation of Pol ι may be involved in the mutagenesis and carcinogenesis induced by environmental chemicals.

11.
Clin Exp Pharmacol Physiol ; 33(9): 802-7, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16922810

RESUMO

1. The aim of the present study was to investigate the mechanism underlying biochanin A-induced relaxation of the aorta in spontaneously hypertensive rats (SHR). 2. The tension in isolated ring preparations of thoracic aortas from normotensive (Wistar-Kyoto (WKY) rats) and SHR at 5 and 10 weeks of age was measured isometrically. 3. Biochanin A (10(-7) to 10(-4) mol/L) induced a concentration-dependent relaxation in aortic rings from both strains at the age of 5 and 10 weeks and the relaxation was greater in rings from 10-week-old SHR compared with age-matched WKY rats. The vasorelaxation induced by biochanin A was significantly reduced by denudation of the endothelium in aortic rings from SHR, but not WKY rats. Treatment with either indomethacin, a cyclo-oxygenase inhibitor, or N(omega)-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, had little effect on the relaxation induced by biochanin A in aortic rings from either strain. Glibenclamide, a selective inhibitor of ATP-sensitive potassium channels, significantly attenuated the relaxation induced by biochanin A in aortic rings from both strains, although the extent of reduction was greater in WKY rats than SHR. Conversely, treatment with 4-aminopyridine, a selective inhibitor of voltage-dependent potassium channels, or tetraethylammonium, an inhibitor of calcium-activated potassium channels, significantly reduced the vasorelaxation induced by biochanin A in rings from SHR but not WKY rats. 4. The greater vasorelaxation produced by biochanin A in aortic rings from 10-week-old SHR is endothelium dependent. Different mechanisms underlie the relaxant effects of biochanin A in aorta from SHR and WKY rats. The mechanisms of biochanin A-induced vasorelaxation in thoracic aortas from both normotensive and hypertensive rats involve ATP-sensitive potassium channels and, in addition, in rings from the hypertensive strain at 10 weeks of age, an endothelium-derived activation of smooth muscle cell potassium channels contributes to the vasorelaxation observed.


Assuntos
Aorta/efeitos dos fármacos , Genisteína/uso terapêutico , Hipertensão/tratamento farmacológico , Vasodilatação/efeitos dos fármacos , Acetilcolina/farmacologia , Animais , Pressão Sanguínea/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Genisteína/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Indometacina/farmacologia , Masculino , NG-Nitroarginina Metil Éster/farmacologia , Nitroprussiato/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Ratos , Ratos Endogâmicos SHR , Ratos Endogâmicos WKY
12.
Conf Proc IEEE Eng Med Biol Soc ; 2005: 2244-7, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-17282679

RESUMO

Epidemiological data suggest that the incidence of cardiovascular disease is reduced in people who have a high intake of phytoestrogens. The plant-derived estrogen biochanin A is known to cause vasodilation, but its mechanisms of action remain unclear. This study was undertaken to investigate the effects and mechanisms of biochanin A on rat thoracic aorta. Isolated aortic rings were suspended in individual organ baths and isometric tension was measured. Biochanin A induced significant relaxation in rings with or without endothelium. Contractile responses induced by phenylephrine (PE), KCl and CaCl2were antagonized by 10-7~10-4mol/L biochanin A. The transient contraction elicited by PE was significantly attenuated by 10-5mol/L biochanin A in Ca2+-free medium. The relaxant effect of biochanin A was significantly inhibited by pretreatment with the K+channel antagonists tetraethylammonium and glibenclamide in endothelium-denuded aorta. We conclude that biochanin A induces an endothelium-independent relaxation in rat aortic rings. The underlying mechanism may involve the blockage of Ca2+entry through both voltage-dependent and receptor-operated Ca2+channels, the inhibition of intracellular Ca2+release, and the activation of large-conductance Ca2+-activated K+channels and ATP-sensitive K+channels.

13.
Pharmacology ; 73(1): 31-40, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15452361

RESUMO

Our previous studies showed that cysteinyl leukotriene receptor-1 (CysLT1) antagonist pranlukast has a neuroprotective effect on cerebral ischemia in rats and mice. However, whether the neuroprotective effect of pranlukast is its special action or a common action of CysLT1 receptor antagonists remains to be clarified. This study was performed to determine whether montelukast, another CysLT1 receptor antagonist, has the neuroprotective effect on focal cerebral ischemia in mice, and to observe its dose- and time-dependent properties. Permanent focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). Montelukast was injected intraperitoneally either as multiple doses (once a day for 3 days and 30 min before MCAO) or as a single dose (at 30 min before, 30 min after, or 1 h after MCAO), respectively, and pranlukast and edaravone were used as controls. The neurological deficits, infarct volumes, brain edema, neuron density, and Evans blue extravasation in the brain were determined 24 h after MCAO. Pretreatments with multiple doses or a single dose of montelukast (0.1 and 1.0 mg/kg) before MCAO significantly attenuated all the ischemic insults. Post-treatment with a single dose of montelukast (0.1 and 1.0 mg/kg) at 30 min after MCAO also significantly decreased brain edema and infarct volume, but not neurological deficits. However, post-treatment with a single dose of montelukast at 1 h after MCAO had no significant effect. Pranlukast showed the same effects as montelukast, but edaravone attenuated the ischemic insults only with multiple doses before MCAO. Thus, montelukast has a dose- and time-dependent neuroprotective effect on permanent focal cerebral ischemia in mice, with an effective dose range of 0.1-1.0 mg/kg and a therapeutic window of 30 min. These findings further support the therapeutic potential of CysLT1 receptor antagonists in the treatment of cerebral ischemia at earlier phases.


Assuntos
Acetatos/farmacologia , Antipirina/análogos & derivados , Isquemia Encefálica/tratamento farmacológico , Antagonistas de Leucotrienos/farmacologia , Quinolinas/farmacologia , Receptores de Leucotrienos/efeitos dos fármacos , Animais , Antipirina/uso terapêutico , Barreira Hematoencefálica/efeitos dos fármacos , Encéfalo/patologia , Edema Encefálico/tratamento farmacológico , Edema Encefálico/patologia , Isquemia Encefálica/mortalidade , Isquemia Encefálica/patologia , Cromonas/farmacologia , Ciclopropanos , Relação Dose-Resposta a Droga , Edaravone , Sequestradores de Radicais Livres/uso terapêutico , Infarto da Artéria Cerebral Média/tratamento farmacológico , Infarto da Artéria Cerebral Média/patologia , Camundongos , Sistema Nervoso/efeitos dos fármacos , Fármacos Neuroprotetores/uso terapêutico , Desempenho Psicomotor/efeitos dos fármacos , Sulfetos , Análise de Sobrevida , Fatores de Tempo
14.
Acta Pharmacol Sin ; 23(10): 871-7, 2002 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-12370090

RESUMO

AIM: To determine whether ONO-1078 (pranlukast), a potent leukotriene receptor antagonist, has neuroprotective effect on focal cerebral ischemia in the rat. METHODS: Focal cerebral ischemia was induced by 30 min of middle cerebral artery (MCA) occlusion and followed by 24 h reperfusion. ONO-1078 (0.003-1.0 mg/kg) or vehicle (saline 1 mL/kg) was ip injected 30 min before MCA occlusion and 2 h after reperfusion. The neurological score, infarct volume, neuron density (in cortex, hippocampus, and striatum), brain edema, and albumin exudation around the vessels were determined 24 h after reperfusion. RESULTS: ONO-1078 slightly improved the neurological deficiency, and dramatically decreased infarct volume and neuron loss which showed a bell shaped dose response effect with highest effect at doses of 0.01-0.3 mg/kg. Enlargement of the ischemic hemisphere and albumin exudation were inhibited at doses of 0.01-1.0 mg/kg. CONCLUSION: ONO-1078 has the protective effect on focal cerebral ischemia in rats, which is partially attributed to the inhibition of brain edema. This may represent a novel approach to the treatment of acute cerebral ischemia with cysteinyl leukotriene receptor antagonists.


Assuntos
Barreira Hematoencefálica/efeitos dos fármacos , Cromonas/farmacologia , Infarto da Artéria Cerebral Média/fisiopatologia , Antagonistas de Leucotrienos/farmacologia , Fármacos Neuroprotetores/farmacologia , Animais , Edema Encefálico/prevenção & controle , Cromonas/uso terapêutico , Antagonistas de Leucotrienos/uso terapêutico , Masculino , Fármacos Neuroprotetores/uso terapêutico , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/prevenção & controle
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