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1.
J Vet Cardiol ; 30: 92-99, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32707334

RESUMEN

INTRODUCTION/OBJECTIVES: The American College of Veterinary Internal Medicine (ACVIM) guidelines suggest that pimobendan should be initiated in dogs which meet all criteria of stage B2 myxomatous mitral valve disease (MMVD): murmur intensity ≥ 3/6, left atrial-to-aortic ratio ≥ 1.6, normalized left ventricular internal diameter in diastole ≥ 1.7, and vertebral heart size > 10.5. Recently, a new radiographic index for left atrial enlargement, vertebral left atrial size (VLAS), was proposed. The objective of the present study was to evaluate whether VLAS is useful in staging MMVD and if it can distinguish between ACVIM stages B1 and B2. ANIMALS: Ninety-seven client-owned dogs with MMVD were evaluated and classified as ACVIM stage B1, B2, or C-D. MATERIALS AND METHODS: The echocardiographs and radiographs of all the dogs were retrospectively evaluated to obtain left atrial-to-aortic ratio, normalized left ventricular internal diameter in diastole, and VLAS values. The data were analyzed to assess the correlation between these measurements and VLAS, and the optimal cutoff value of VLAS was determined. RESULTS: A VLAS cutoff value of 2.6 provided the greatest diagnostic accuracy for identification of dogs with ACVIM stage B2 MMVD (area under the curve, 0.96; sensitivity, 95%; specificity, 84%). A VLAS ≥2.5 exhibited the highest sensitivity (sensitivity, 100%; specificity, 78%), and a VLAS ≥ 3.1 exhibited the highest specificity (sensitivity, 47%; specificity, 100%). CONCLUSIONS: VLAS is a helpful index for monitoring MMVD using radiography. A VLAS cutoff value of 2.5 could be used to identify dogs that may benefit from echocardiography to determine if they have reached ACVIM stage B2.


Asunto(s)
Enfermedades de los Perros/diagnóstico por imagen , Atrios Cardíacos/diagnóstico por imagen , Insuficiencia de la Válvula Mitral/veterinaria , Animales , Perros , Femenino , Masculino , Insuficiencia de la Válvula Mitral/diagnóstico por imagen , Radiografía Torácica/veterinaria , Registros/veterinaria , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad
2.
Vet J ; 197(2): 445-50, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23570775

RESUMEN

Plasma N-terminal pro B-type natriuretic peptide (NT-proBNP) concentrations increase in dogs with azotemia. However, the correlation between glomerular filtration rate (GFR) and NT-proBNP concentrations in dogs has not been evaluated. The objective of this study was to evaluate the correlation between GFR and plasma NT-proBNP concentrations in dogs with chronic kidney disease (CKD). In this retrospective cross-sectional study, plasma creatinine (Cre) and NT-proBNP concentrations, plasma iohexol clearance (PCio) values and blood pressure were measured in dogs with CKD. Dogs were classified according to PCio values into D group (dogs with decreased PCio values), and N group (dogs with normal PCio values). Dogs were further categorized on the basis of their systolic blood pressure and PCio values into NT-D group (normotensive dogs with decreased PCio values), NT-N group (normotensive dogs with normal PCio values), HT-D group (hypertensive dogs with decreased PCio values) and HT-N group (hypertensive dogs with normal PCio values). Significant correlations were observed between plasma NT-proBNP and Cre concentrations (r=0.360, P<0.05) and PCio values (r=-0.470, P<0.01). Plasma NT-proBNP concentrations were significantly higher in the D group than in the N group (P<0.001). Plasma NT-proBNP concentrations were significantly higher in the HT-D group than in the other three groups (P ≤ 0.007). No differences in plasma NT-proBNP concentrations were observed between the NT-D and HT-N groups (P=0.28). Plasma NT-proBNP concentrations were significantly lower in the NT-N group than in the other three groups (P ≤ 0.043). Our findings suggest that decreased GFR might be associated with increased plasma NT-proBNP concentrations in dogs, similar to that in humans. In addition, the complication of hypertension in CKD might be associated with further increases in plasma NT-proBNP concentrations. In conclusion, the effects of GFR and blood pressure on the plasma NT-proBNP concentration were small, but it could be necessary to consider the effects when this marker is used to evaluate canine cardiac disease.


Asunto(s)
Enfermedades de los Perros/sangre , Tasa de Filtración Glomerular/veterinaria , Péptido Natriurético Encefálico/sangre , Fragmentos de Péptidos/sangre , Insuficiencia Renal Crónica/veterinaria , Animales , Enfermedades de los Perros/metabolismo , Perros , Femenino , Tasa de Filtración Glomerular/fisiología , Masculino , Insuficiencia Renal Crónica/sangre , Insuficiencia Renal Crónica/metabolismo , Estudios Retrospectivos
3.
Br J Cancer ; 106(12): 1934-9, 2012 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-22555398

RESUMEN

BACKGROUND: This randomised phase II trial compared gemcitabine alone vs gemcitabine and S-1 combination therapy in advanced pancreatic cancer. METHODS: Patients were randomly assigned to 4-week treatment with gemcitabine alone (1000, mg m(-2) gemcitabine by 30-min infusion on days 1, 8, and 15) or gemcitabine and S-1 combination therapy (1000, mg m(-2) gemcitabine by 30-min infusion on days 1 and 15 and 40 mg m(-2) S-1 orally twice daily on days 1-15). The primary end point was progression-free survival (PFS). RESULTS: Between July 2006 and February 2009, 106 patients were enrolled. The PFS in gemcitabine and S-1 combination arm was significantly longer than in gemcitabine arm (5.4 vs 3.6 months), with a hazard ratio of 0.64 (P=0.036). Overall survival (OS) for gemcitabine and S-1 combination was longer than that for gemcitabine monotherapy (13.5 vs 8.8 months), with a hazard ratio of 0.72 (P=0.104). Overall, grade 3 or 4 adverse events were similar in both arms. CONCLUSION: Gemcitabine and S-1 combination therapy demonstrated longer PFS in advanced pancreatic cancer. Improved OS duration of 4.7 months was found for gemcitabine and S-1 combination therapy, though this was not statistically significant.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Desoxicitidina/análogos & derivados , Ácido Oxónico/administración & dosificación , Neoplasias Pancreáticas/tratamiento farmacológico , Tegafur/administración & dosificación , Adulto , Anciano , Anciano de 80 o más Años , Desoxicitidina/administración & dosificación , Supervivencia sin Enfermedad , Combinación de Medicamentos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Gemcitabina
4.
Nat Nanotechnol ; 4(3): 158-61, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19265844

RESUMEN

In the field of spintronics, researchers have manipulated magnetization using spin-polarized currents. Another option is to use a voltage-induced symmetry change in a ferromagnetic material to cause changes in magnetization or in magnetic anisotropy. However, a significant improvement in efficiency is needed before this approach can be used in memory devices with ultralow power consumption. Here, we show that a relatively small electric field (less than 100 mV nm(-1)) can cause a large change (approximately 40%) in the magnetic anisotropy of a bcc Fe(001)/MgO(001) junction. The effect is tentatively attributed to the change in the relative occupation of 3d orbitals of Fe atoms adjacent to the MgO barrier. Simulations confirm that voltage-controlled magnetization switching in magnetic tunnel junctions is possible using the anisotropy change demonstrated here, which could be of use in the development of low-power logic devices and non-volatile memory cells.

5.
Can J Gastroenterol ; 21(12): 809-13, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-18080052

RESUMEN

PURPOSE: Gallbladder cancer (GBC) has a poor prognosis that is related to delayed diagnosis. The present study evaluated the efficacy of the transcystic ductal approach in diagnosing GBC. METHODS: A catheter was introduced into the gallbladder endoscopically via the cystic duct to obtain bile for cytology. Subsequently, cytology specimens were collected using a brush, and intraductal ultrasonography (IDUS) was performed using a miniature probe in patients suspected of having GBC. RESULTS: Bile cytology was performed successfully in 23 of 25 patients (92%). The sensitivity, specificity and accuracy of cytology were 44.4%, 100% and 78.3%, respectively. Brush cytology and IDUS were successful in six of eight (75%) and nine of 15 (60%) patients, respectively. Brush cytology was positive in two of five patients with GBC. In all four patients with invasive cancer, IDUS showed an irregularity or disruption of the outermost hyperechoic layer. CONCLUSIONS: The endoscopic transpapillary approach to the gallbladder was useful for the diagnosis of GBC. Brush cytology and IDUS may improve diagnostic efficacy and provide more useful information.


Asunto(s)
Ampolla Hepatopancreática , Endoscopía del Sistema Digestivo/métodos , Endosonografía/métodos , Neoplasias de la Vesícula Biliar/diagnóstico , Anciano , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Estudios Retrospectivos
6.
Intern Med J ; 36(1): 58-61, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16409315

RESUMEN

Autoimmune pancreatitis (AIP) has extrapancreatic complications such as Sjögren's syndrome, retroperitoneal fibrosis and sclerosing cholangitis. We studied 30 patients with AIP. Of these, we identified pulmonary involvement in four patients during follow up. Among them, two patients had respiratory failure. They showed good response to steroid therapy, but a higher dose of prednisolone was necessary to maintain remission than that required in biliary involvement. Elevation of immunoglobulin G(4) and Krebs von den Lungen-6 levels were characteristic of pulmonary involvement. They may be useful for early detection of pulmonary complication.


Asunto(s)
Enfermedades Autoinmunes/complicaciones , Pancreatitis/complicaciones , Anciano , Colangiopancreatografia Retrógrada Endoscópica , Femenino , Glucocorticoides/administración & dosificación , Humanos , Hipoxia/etiología , Masculino , Persona de Mediana Edad , Terapia por Inhalación de Oxígeno , Pancreatitis/inmunología , Prednisolona/administración & dosificación , Insuficiencia Respiratoria/etiología , Insuficiencia Respiratoria/terapia
7.
Artículo en Inglés | MEDLINE | ID: mdl-17236649

RESUMEN

It is widely recognized that nitric oxide (NO) in mammalian tissues is produced from L-arginine via catalysis by NO synthase (NOS) isoforms such as neuronal NOS (nNOS) and endothelial NOS (eNOS) that are constitutively expressed mainly in the central and peripheral nervous system and vascular endothelial cells, respectively. This review concentrates only on these constitutive NOS (cNOS) isoforms while excluding information about iNOS, which is induced mainly in macrophages upon stimulation by cytokines and polysaccharides. The NO signaling pathway plays a crucial role in the functional regulation of mammalian tissues and organs. Evidence has also been accumulated for the role of NO in invertebrates and non-mammalian vertebrates. Expression of nNOS in the brain and peripheral nervous system is widely determined by staining with NADPH (reduced nicotinamide adenine dinucleotide phosphate) diaphorase or NOS immunoreactivity, and functional roles of NO formed by nNOS are evidenced in the early phylogenetic stages (invertebrates and fishes). On the other hand, the endothelium mainly produces vasodilating prostanoids rather than NO or does not liberate endothelium-derived relaxing factor (EDRF) (fishes), and the ability of endothelial cells to liberate NO is observed later in phylogenetic stages (amphibians). This review article summarizes various types of interesting information obtained from lower organisms (invertebrates, fishes, amphibians, reptiles, and birds) about the properties and distribution of nNOS and eNOS and also the roles of NO produced by the cNOS as an important intercellular signaling molecule.


Asunto(s)
Óxido Nítrico/biosíntesis , Filogenia , Anfibios/metabolismo , Animales , Aves/metabolismo , Peces/metabolismo , Invertebrados/metabolismo , Óxido Nítrico Sintasa de Tipo I/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Reptiles/metabolismo
8.
Gut ; 54(5): 698-702, 2005 May.
Artículo en Inglés | MEDLINE | ID: mdl-15831919

RESUMEN

BACKGROUND AND AIMS: Percutaneous tumour ablation (PTA), such as ethanol injection and radiofrequency ablation, is now recognised as a primary treatment for hepatocellular carcinoma (HCC). Although PTA is a relatively safe procedure, it can cause biliary obstruction as a rare complication. As patients with cirrhosis undergoing surgery or endoscopic retrograde cholangiopancreatography/sphincterotomy have a high mortality rate from bleeding, we adopted the use of endoscopic papillary balloon dilatation (EPBD) in these patients and now report the results. We retrospectively analysed the incidence of biliary obstruction after PTA and the efficacy of treatment with EPBD. PATIENTS AND METHODS: A total of 1043 patients with HCC were treated by PTA, of whom 538 were treated with transarterial embolisation with up to eight years of follow up. RESULTS: There were 17 (1.6%) cases of hilar obstruction due to tumour progression and 35 (3.4%) cases of extrahepatic obstruction. Apart from the expected causes of biliary obstruction (haemobilia n = 11, gallstones n = 11, and three miscellaneous causes), we found that 10 patients had obstruction due to biliary casts. This is the first description of biliary casts after percutaneous tumour ablation therapy. Extrahepatic biliary obstruction by procedure related haemobilia occurred within three days of PTA while other causes occurred between 0 and 17 (average 4.9) months. Biliary casts occurred more frequently after ethanol injection than after radiofrequency ablation. EPBD successfully dissipated biliary obstruction in 33 of 35 cases, while two died due to hepatic failure despite successful drainage. CONCLUSIONS: Extrahepatic biliary obstruction is an uncommon complication after PTA for HCC, and can be safely and effectively treated with EPBD, despite impaired liver function.


Asunto(s)
Carcinoma Hepatocelular/terapia , Ablación por Catéter/efectos adversos , Colestasis Extrahepática/etiología , Embolización Terapéutica/efectos adversos , Neoplasias Hepáticas/terapia , Adulto , Anciano , Anciano de 80 o más Años , Cateterismo , Colangiopancreatografia Retrógrada Endoscópica , Colestasis Extrahepática/diagnóstico por imagen , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento
9.
Gut ; 53(5): 729-34, 2004 May.
Artículo en Inglés | MEDLINE | ID: mdl-15082593

RESUMEN

BACKGROUND AND AIM: Covered self-expandable metal stents (EMS) were recently developed to overcome tumour ingrowth in conventional EMS. However, supporting evidence for the efficacy of covered EMS is lacking. PATIENTS AND METHODS: We enrolled 112 patients with unresectable distal biliary malignancies. They were randomly assigned to polyurethane covered (n = 57) or original diamond stent (n = 55). RESULTS: Stent occlusion occurred in eight patients (14%) after a mean of 304 days in the covered group, and in 21 patients (38%) after a mean of 166 days in the uncovered group. The incidence of covered EMS occlusion was significantly lower than that of uncovered EMS (p = 0.0032). The cumulative stent patency of covered stents was significantly higher than that of uncovered stents (p = 0.0066). No tumour ingrowth occurred in the covered group while it was observed in 15 patients in the uncovered group. In subgroup analysis, the cumulative patency of the covered EMS was significantly higher in pancreatic cancer (p = 0.0363) and metastatic lymph nodes (p = 0.0354). There was no significant difference in survival between the two groups. Acute cholecystitis was observed in two of the covered group and in none of the uncovered group. Mild pancreatitis occurred in five of the covered group and in one of the uncovered group. CONCLUSIONS: Covered diamond stents successfully prevented tumour ingrowth and were significantly superior to uncovered stents for the treatment of patients with distal malignant biliary obstruction. However, careful attention must be paid to complications specific to covered self-expandable metal stents, such as acute cholecystitis and pancreatitis.


Asunto(s)
Neoplasias del Sistema Biliar/cirugía , Colestasis/cirugía , Stents , Enfermedad Aguda , Adulto , Anciano , Anciano de 80 o más Años , Neoplasias del Sistema Biliar/complicaciones , Colangiopancreatografia Retrógrada Endoscópica , Colecistitis/etiología , Colestasis/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Cuidados Paliativos/métodos , Pancreatitis/etiología , Poliuretanos , Estudios Prospectivos , Falla de Prótesis , Stents/efectos adversos , Propiedades de Superficie , Análisis de Supervivencia
10.
Br J Anaesth ; 92(4): 541-3, 2004 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-14766717

RESUMEN

BACKGROUND: Sore throat and hoarseness are common complications, but these have not been studied after total i.v. anaesthesia. METHODS: We prospectively studied 418 surgical patients, aged 15-92 yr, after total i.v. anaesthesia with propofol, fentanyl and ketamine to assess possible factors associated with sore throat and hoarseness. RESULT: We found sore throat in 50% and hoarseness in 55% of patients immediately after surgery. This decreased to 25% for sore throat and 24% for hoarseness on the day after surgery. Both sore throat and hoarseness were more common in females and when lidocaine spray had been used. Cricoid pressure during laryngoscopy was inversely associated with the risk of sore throat. CONCLUSION: Knowledge of these factors may reduce postoperative throat complications, and improve patient satisfaction.


Asunto(s)
Anestesia Intravenosa/efectos adversos , Ronquera/etiología , Faringitis/etiología , Complicaciones Posoperatorias/etiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Anestesia Intravenosa/métodos , Femenino , Humanos , Laringoscopía , Lidocaína/efectos adversos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Riesgo , Factores Sexuales
11.
Spine (Phila Pa 1976) ; 26(20): 2220-6, 2001 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-11598512

RESUMEN

STUDY DESIGN: A radiographic study in 22 patients using magnetic resonance imaging was conducted. OBJECTIVE: To describe the relation between postoperative cervical alignment and morphologic evaluation of the cervical extensor musculature, especially semispinalis cervics in laminoplasty. SUMMARY OF BACKGROUND DATA: Cervical laminoplasty has been widely accepted as a treatment for cervical myelopathy. Posterior procedures, however, involve the extensor musculature of the cervical spine. METHODS: In this study, 22 patients who underwent laminoplasty for repair of the extensor musculature were reviewed prospectively. The semispinalis cervics was evaluated by coronal view of the magnetic resonance image 1 month, 12 months, and 24 months after surgery. Cervical alignment at last follow-up assessment was compared with preoperative alignment using the lateral view of cervical radiographs. RESULTS: In 18 patients (82%), morphologic repair of semispinalis cervics had been maintained (Group A), but in 4 patients (18%), but it had not been maintained at the last follow-up assessment (Group B). Cervical alignment in Group A had been maintained, but maximum loss of cervical lordosis occurred in Group B. Moreover, Group B consisted of elderly women. CONCLUSIONS: The findings from this magnetic resonance imaging study suggest that the degree of semispinalis cervics repair affects postoperative cervical alignment, and significant loss of cervical lordosis tends to occur in elderly women who undergo laminoplasty.


Asunto(s)
Vértebras Cervicales/cirugía , Laminectomía/efectos adversos , Músculo Esquelético/patología , Procedimientos de Cirugía Plástica/efectos adversos , Cicatrización de Heridas , Adulto , Anciano , Vértebras Cervicales/diagnóstico por imagen , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Músculo Esquelético/cirugía , Estudios Prospectivos , Radiografía
12.
J Toxicol Environ Health A ; 63(6): 429-35, 2001 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-11482798

RESUMEN

The effects of diesel exhaust particles (DEP) on pulmonary functions and consequent diseases are well known, but there have been few reports concerning involvement of the cardiovascular system. In order to assess a direct action of DEP on cardiac tissue, the effects on blood pressure of intravenous administration of 12 or 120 mg/kg DEP to anesthetized rats were studied for a 15-min period. DEP (120 mg/kg) significantly lowered blood pressure for 25 s with no signs of arrhythmia or mortality, a phenomenon seen in guinea pigs. After 25 s blood pressure gradually returned to control levels and was maintained for 15 min. The 12-mg/kg DEP concentration did not markedly affect rat blood pressure. Pretreatment with atropine (24 mg/kg) blocked the DEP-induced fall in blood pressure, while pretreatment with propranolol (48 mg/kg) proved ineffective against DEP, suggesting involvement of the parasympathetic system. Data show that the rat is less sensitive to DEP-induced effects on blood pressure and may be a poor model to reflect cardiovascular changes.


Asunto(s)
Sistema Nervioso Autónomo/efectos de los fármacos , Presión Sanguínea/efectos de los fármacos , Emisiones de Vehículos/toxicidad , Antagonistas Adrenérgicos beta/farmacología , Animales , Atropina/farmacología , Relación Dosis-Respuesta a Droga , Inyecciones Intravenosas , Masculino , Parasimpatolíticos/farmacología , Tamaño de la Partícula , Propranolol/farmacología , Ratas , Ratas Wistar
13.
Eur J Pharmacol ; 423(2-3): 179-83, 2001 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-11448483

RESUMEN

The selectivity of 7-nitroindazole in inhibiting endothelial and neuronal nitric oxide synthases (eNOS and nNOS) was investigated by comparing its inhibitory action on relaxations mediated by nitric oxide (NO) in response to stimulation of perivascular nerves and in response to histamine in monkey cerebral artery strips. 7-Nitroindazole at 2 x 10(-5) M moderately attenuated the response to transmural electrical stimulation and to nicotine, but did to alter the endothelium-dependent relaxation in response to histamine in cimetidine-treated strips. Raising the concentration of 7-nitroindazole to 10(-4) M abolished the neurogenic response, partially inhibited the histamine-induced relaxation, but did not affect the response to NO. It is concluded that 7-nitroindazole is a relatively selective nNOS inhibitor; however, at high concentrations, it inhibits eNOS in monkey cerebral arteries.


Asunto(s)
Arterias Cerebrales/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Indazoles/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Animales , Arginina/farmacología , Arterias Cerebrales/enzimología , Arterias Cerebrales/fisiología , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Endotelio Vascular/fisiología , Histamina/farmacología , Técnicas In Vitro , Macaca , Nicotina/farmacología , Óxido Nítrico/farmacología , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo I , Vasoconstricción/efectos de los fármacos , Vasodilatación/efectos de los fármacos
14.
J Toxicol Environ Health A ; 63(2): 115-26, 2001 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-11393798

RESUMEN

To investigate the effects of diesel exhaust (DE) particles on the reproductive system, male Fischer 344 rats at 13 mo of age were exposed to clean air or DE at particle concentrations of 0.3, 1, or 3 mg/m3 for 8 mo. DE did not markedly affect testicular and body weights. However, DE at 0.3 mg/m3 significantly decreased prostate and coagulating gland weights, accompanied by a reduction in thymus and adrenal gland weight. In contrast, there was a significant rise in the weights of prostate, seminal vesicles, and coagulating glands in the 3 mg/m3 DE group. In rats exposed to 0.3 or 1 mg/m3 DE, serum luteinizing hormone (LH) and testosterone increased significantly, while a rise in testicular testosterone was noted with 3 mg/m3 DE. The concentrations of follicle-stimulating hormone (FSH) and inhibin as well as the sperm head counts were not markedly altered in any treatment group. Positive staining with inhibin-alpha subunit and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) were observed in Sertoli cells and Leydig cells, respectively. Immunolocalization of inhibin-alpha subunit and 3beta-HSD was not changed by exposure to DE. In conclusion, DE appears to exert greater effects on accessory glands than on testes in Fischer 344 rats, and the responsiveness of rats is less than that found in mice.


Asunto(s)
Genitales Masculinos/efectos de los fármacos , Hormonas Testiculares/sangre , Testículo/efectos de los fármacos , Emisiones de Vehículos/toxicidad , 3-Hidroxiesteroide Deshidrogenasas/metabolismo , Análisis de Varianza , Animales , Biometría , Hormona Folículo Estimulante/sangre , Genitales Masculinos/citología , Genitales Masculinos/metabolismo , Inmunohistoquímica , Inhibinas/sangre , Inhibinas/metabolismo , Células Intersticiales del Testículo/efectos de los fármacos , Hormona Luteinizante/sangre , Masculino , Radioinmunoensayo , Ratas , Ratas Endogámicas F344 , Células de Sertoli/efectos de los fármacos , Recuento de Espermatozoides , Testículo/citología , Testículo/metabolismo , Testosterona/sangre
15.
Eur J Pharmacol ; 420(1): 67-72, 2001 May 18.
Artículo en Inglés | MEDLINE | ID: mdl-11412840

RESUMEN

Canine cerebral arterial strips denuded of endothelium responded to nicotine and transmural electrical stimulation with relaxations, which were abolished by NG-nitro-L-arginine and methylene blue. Magnitudes of relaxation did not differ in the arteries contracted with prostaglandin F2alpha and sumatriptan, an effective therapeutic of migraine. Sumatriptan concentration-dependently contracted the arteries responding to 2 Hz stimulation with persistent relaxations, and the concentration of this 5-HT1B/1D/1F receptor agonist to overcome the relaxation averaged 1.06 x 10(-7) M. Acetylcholine inhibited the response to nerve stimulation due possibly to its action on prejunctional nitroxidergic nerves; the inhibition did not differ in the arteries contracted with prostaglandin F2alpha and K+. It appears that sumatriptan does not interfere with the release of nitric oxide from nerves but counteracts the neurogenic relaxation by functional antagonistic action on smooth muscle. Prejunctional inhibition by muscarinic receptor activation is unlikely associated with opening of neuronal K+ channels.


Asunto(s)
Acetilcolina/farmacología , Arterias Cerebrales/efectos de los fármacos , Óxido Nítrico/fisiología , Agonistas de Receptores de Serotonina/farmacología , Sumatriptán/farmacología , Vasodilatación/efectos de los fármacos , Animales , Arterias Cerebrales/inervación , Arterias Cerebrales/fisiología , Dinoprost/farmacología , Perros , Relación Dosis-Respuesta a Droga , Estimulación Eléctrica , Femenino , Técnicas In Vitro , Masculino , Nicotina/farmacología , Óxido Nítrico/farmacología , Potasio/farmacología , Vasodilatadores/farmacología
16.
J Cardiovasc Pharmacol ; 37(5): 585-95, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11336109

RESUMEN

The present study aimed to determine the action of angiotensin II and to pharmacologically analyze mechanisms of their action in isolated uterine arteries. Canine and human uterine artery strips were suspended in Ringer-Locke solutions for isometric tension recording. Canine and human uterine arteries responded to angiotensin II with transient contraction followed by relaxation, which were abolished by losartan, an AT1 receptor subtype antagonist. Cyclooxygenase inhibitors augmented the contraction and abolished the relaxation. The relaxation was also abolished or suppressed by tranylcypromine, a prostaglandin I2 synthesis inhibitor. The relaxant response of dog uterine arteries to angiotensin II was partially suppressed by endothelium denudation but was not influenced by nitric oxide synthase inhibitor. Conversely, the response of human uterine arteries to the peptide was unaffected by endothelium denudation. The antagonists used and endothelium denudation did not inhibit the relaxation caused by a prostaglandin I2 analogue. It appears that the angiotensin II-induced relaxation is mediated by vasodilator prostaglandins, possibly prostaglandin I2, released from both endothelium and subendothelial tissues in dog uterine arteries. In human uterine arteries, the vasodilator prostaglandin is released from subendothelial tissues due to AT1 receptor stimulation by the peptide.


Asunto(s)
Angiotensina II/farmacología , Endotelio Vascular/efectos de los fármacos , Útero/irrigación sanguínea , Útero/efectos de los fármacos , Vasoconstrictores/farmacología , Vasodilatación/efectos de los fármacos , Adulto , Anciano , Animales , Arterias/efectos de los fármacos , Arterias/metabolismo , Aspirina/farmacología , Perros , Relación Dosis-Respuesta a Droga , Endotelio Vascular/metabolismo , Epoprostenol/análogos & derivados , Epoprostenol/metabolismo , Epoprostenol/farmacología , Femenino , Humanos , Persona de Mediana Edad , Inhibidores de la Monoaminooxidasa/farmacología , Inhibidores de Agregación Plaquetaria/farmacología , Tranilcipromina/farmacología , Útero/metabolismo , Vasoconstricción/efectos de los fármacos , Vasoconstricción/fisiología , Vasodilatación/fisiología
17.
J Ethnopharmacol ; 76(1): 109-13, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11378291

RESUMEN

The aqueous extract of the Panax ginseng (GE) potentiated the relaxation induced by transmural electrical stimulation or nicotine in monkey cerebral arterial strips denuded of the endothelium and partially contracted with prostaglandin F(2 alpha). The response to electrical stimulation was abolished by tetrodotoxin, whereas that to nicotine was suppressed by hexamethonium. N(G)-nitro-L-arginine abolished both of the neurogenic relaxation. Atropine did not alter the potentiating effect of GE. Relaxations induced by exogenous NO were unaffected by GE. The enhancement by GE, of the neurogenic response, appears to be associated with increment in the synthesis or release of NO from the perivascular nerve. Blockade of muscarinic prejunctional inhibition, superoxide scavenging action and phosphodiesterase inhibition are not involved.


Asunto(s)
Fármacos del Sistema Nervioso Central/farmacología , Óxido Nítrico/farmacología , Extractos Vegetales/farmacología , Saponinas/farmacología , Vasodilatación/efectos de los fármacos , Animales , Arterias Cerebrales/efectos de los fármacos , Cromatografía Líquida de Alta Presión , Sinergismo Farmacológico , Estimulación Eléctrica , Femenino , Ginsenósidos , Macaca , Masculino
18.
Eur J Pharmacol ; 415(2-3): 209-16, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11275001

RESUMEN

Mechanisms underlying celiprolol-induced vasodilatation were analyzed in isolated porcine coronary arteries. Celiprolol induced dose-related relaxation of the artery rings with endothelium, an effect which was suppressed by N(G)-nitro-L-arginine methylester (L-NAME), nitric oxide (NO) scavenger, guanylate cyclase inhibitor, endothelium denudation, and removal of Ca(2+). L-NAME contracted, and superoxide dismutase relaxed, the arteries only when the endothelium was preserved. Neither superoxide dismutase nor beta-adrenoceptor antagonists changed celiprolol-induced relaxations. Celiprolol increased the cyclic GMP content in the tissue. The release of NO from endothelium, estimated by the extracellular production of cyclic GMP in arteries incubated in medium containing guanylate cyclase and GTP, was augmented by celiprolol, and L-NAME abolished this action of celiprolol. It is concluded that celiprolol elicits relaxation by acting on sites other than beta-adrenoceptors in the endothelium and by releasing NO, which activates soluble guanylate cyclase in smooth muscle and produces cyclic GMP. Scavenging of superoxide anions from the endothelium does not seem to account for the induced relaxation.


Asunto(s)
Antagonistas de Receptores Adrenérgicos beta 1 , Antagonistas Adrenérgicos beta/farmacología , Celiprolol/farmacología , Vasos Coronarios/efectos de los fármacos , Óxido Nítrico Sintasa/efectos de los fármacos , Vasodilatación/efectos de los fármacos , Animales , Vasos Coronarios/metabolismo , GMP Cíclico/metabolismo , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Depuradores de Radicales Libres/farmacología , NG-Nitroarginina Metil Éster/farmacología , Óxido Nítrico Sintasa/metabolismo , Óxido Nítrico Sintasa de Tipo III , Superóxido Dismutasa/farmacología , Porcinos , Vasodilatación/fisiología
19.
Hypertens Res ; 24(1): 47-53, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11213030

RESUMEN

Cerebral arteries are innervated by nitric oxide (NO)-mediated vasodilator nerves, and hypoxia has been shown to attenuate neurogenic vasorelaxation. The present study examines the effects of hypothermia on neurogenic vasorelaxation and on the hypoxia-induced inhibition of the neurogenic vasorelaxation response. In isolated canine cerebral arteries, relaxant responses to transmural electrical stimulation (5 Hz for 40 s), mediated via NO synthesized from L-arginine, were not influenced by lowering the bathing media temperature from 37 degrees C to 30 degrees C but were attenuated at 25 degrees C. On the other hand, relaxations caused by nicotine and exogenous NO were not significantly attenuated but were prolonged by cooling to 25 degrees C. The responses associated with nerve stimulation by electrical pulses or nicotine were depressed by hypoxia (from about 500 mmHg of partial O2 pressure to about 45 mmHg) under normothermia. However, hypothermia at 25 degrees C prevented the inhibition by hypoxia of the neurogenic relaxation. It is concluded that the hypothermia-induced inhibition in the response to electrical nerve stimulation is not associated with a decreased synthesis and release of NO in vasodilator nerves nor with a reduced ability of smooth muscle to relax in response to NO. Interference with the propagation of action potentials might be involved in the inhibition via a fall of temperature. The fact that the hypoxia-induced impairment of vasodilator nerve function was prevented by cooling may partially explain the efficacy of hypothermia in protecting against ischemic neuronal injury in the brain.


Asunto(s)
Arterias Cerebrales/fisiología , Hipotermia/fisiopatología , Hipoxia Encefálica/fisiopatología , Músculo Liso Vascular/fisiología , Óxido Nítrico/fisiología , Animales , Arterias Cerebrales/efectos de los fármacos , Perros , Estimulación Eléctrica , Femenino , Técnicas In Vitro , Masculino , Relajación Muscular/efectos de los fármacos , Relajación Muscular/fisiología , Músculo Liso Vascular/efectos de los fármacos , Nicotina/farmacología , Agonistas Nicotínicos/farmacología , Óxido Nítrico/farmacología , Temperatura , Vasodilatación/efectos de los fármacos , Vasodilatación/fisiología
20.
Pacing Clin Electrophysiol ; 24(11): 1660-3, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11816636

RESUMEN

Doppler index is the sum of isovolumetric contraction time and isovolumetric relaxation time divided by ejection time and has clinical value as an index of combined systolic and diastolic myocardial performance. This crossover study compared the Doppler index and atrial natriuretic hormone (atrial natriuretic peptide) [ANP] between optimal (AV) delay and prolonged AV delay in patients with DDD pacemakers. The study included 14 patients (6 men, 8 women, age 78.4+/-9.3 [SD] years) with AV block with an implanted DDD pacemaker. AV delay was prolonged in a 25-ms, stepwise fashion starting from 125 ms to 250 ms. Pacing rate was set at 70 beats/min. Cardiac output (CO) was assessed by pulsed Doppler echocardiography, and optimal AV delay was defined as the AV delay at which CO was maximum, and an AV delay setting of 250 ms as prolonged AV delay. Plasma level of ANP and Doppler index determined by echocardiography were measured 1 week after programming. AV delay was switched to another AV delay and measurements were repeated after 1 week. Optimal AV delay was 159+/-19 ms. Doppler index was significantly lower at optimal AV delay than at prolonged AV delay (0.68+/-0.26 vs 0.92+/-0.30, P < 0.05). The plasma ANP level was significantly lower at optimal AV delay than at prolonged AV delay (29.0+/-30.7 vs 52.6+/-44.9 pg/mL, P < 0.05). In conclusion, the Doppler index and the plasma ANP level were significantly lower at optimal AV delay than at prolonged AV delay. This study shows the importance of the optimal AV delay setting in patients with an implanted DDD pacemaker, the Doppler index and plasma ANP levels are good indicators for optimizing AV delay.


Asunto(s)
Factor Natriurético Atrial/sangre , Estimulación Cardíaca Artificial/métodos , Bloqueo Cardíaco/terapia , Contracción Miocárdica/fisiología , Marcapaso Artificial , Anciano , Anciano de 80 o más Años , Nodo Atrioventricular/fisiopatología , Gasto Cardíaco , Estudios Cruzados , Ecocardiografía Doppler de Pulso , Femenino , Bloqueo Cardíaco/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Volumen Sistólico , Función Ventricular Izquierda/fisiología
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