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1.
Sci Rep ; 12(1): 19278, 2022 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-36369433

RESUMEN

Materials may behave in non-expected ways when subject to unexpected conditions. For example, when Bi was turned into an amorphous phase (a-Bi) unexpectedly it became a superconductor at temperatures below 10 K. Using the superconductivity of the amorphous phase we provided an explanation as to why crystalline bismuth (c-Bi) had not been found to superconduct, and even predicted an upper limit for its superconducting transition temperature Tc. This was experimentally corroborated within the following year. We now decided to investigate what happens to the crystalline, Wyckoff structure, and amorphous Bi when pressures below the atmospheric are applied. Here it is shown that, within the BCS approach, under expansion the Wyckoff c-Bi increases its superconducting transition temperature minimally, whereas the amorphous phase decreases its Tc. The electron densities of states (eDoS), the vibrational densities of states (vDoS) and the Debye temperatures (θD) are calculated to perform this qualitative evaluation. Expansion can be obtained in the laboratory by chemically etching Bi-based alloys, for example, a process also known as dealloying.

2.
Colorectal Dis ; 22(11): 1714-1723, 2020 11.
Artículo en Inglés | MEDLINE | ID: mdl-32619064

RESUMEN

AIM: The aim of the study was to compare the incidence of perineal hernia and the perineal wound morbidity following extralevator abdominoperineal excision (ELAPE) between two groups - primary perineal closure and reconstruction with a biological mesh. METHOD: One hundred and forty-seven consecutive patients who underwent ELAPE for primary rectal cancer between January 2007 and December 2018 in two tertiary referral centres were retrospectively identified from prospective databases. Perineal closure was carried out via primary closure or with a biological mesh (porcine dermal collagen mesh). Outcome measures were perineal hernia and perineal wound morbidity (infection, dehiscence, persistent sinus and chronic pain). RESULTS: A total of 139 patients were included in the study. A prophylactic mesh was used in 80 (57.5%) and primary closure was practised in 59 (42.4%) patients. The median follow-up was 30 (interquartile range 46.88) months. Thirty patients (21.6%) developed perineal hernia. No significant differences were found between prophylactic mesh and primary closure (16.3% vs 23.3%, P = 0.07). The median period between surgery and hernia diagnosis was 8 months in the primary closure group and 24 months in the mesh group (P < 0.01). Perineal wound morbidity was significantly higher in the prophylactic mesh group (55% vs 33.9%, P < 0.01). CONCLUSION: In our study, the use of a biological mesh did not reduce the rate of perineal hernia, although it did delay its appearance. Perineal closure using a biological mesh may increase perineal morbidity, both acute and chronic.


Asunto(s)
Proctectomía , Neoplasias del Recto , Animales , Humanos , Morbilidad , Perineo/cirugía , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/prevención & control , Proctectomía/efectos adversos , Neoplasias del Recto/cirugía , Estudios Retrospectivos , Mallas Quirúrgicas , Porcinos
3.
J Psychol ; 151(8): 789-803, 2017 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-29166223

RESUMEN

The purpose of this study was to investigate the extent to which a reminiscence intervention reduces depressed mood and improves life satisfaction and psychological well-being. 160 healthy elderly people participated in a 10-session intervention. An experimental design with pretest and posttest evaluations was applied, comparing a control group to an intervention group to evaluate the effects of the program. Follow-up measures were also taken to find out whether the intervention's positive effects lasted over time. Mixed Model ANOVAs showed significant increases in the time-group interaction, life satisfaction, and psychological well-being measures, and decreases in depressed mood, after treatment. The effects remained after three months in the case of life satisfaction and some dimensions of psychological well-being, but they were lower on depressed mood. This study provides additional support for the effectiveness of a reminiscence program as a useful intervention to improve the quality of life of older adults.


Asunto(s)
Depresión/psicología , Depresión/terapia , Memoria Episódica , Satisfacción Personal , Calidad de Vida , Anciano , Análisis de Varianza , República Dominicana , Femenino , Estudios de Seguimiento , Humanos , Masculino
4.
Colorectal Dis ; 17(8): 689-97, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25735444

RESUMEN

AIM: The management of rectal cancer threatening or affecting the prostatic plane is still under debate. The role of preoperative chemo radiotherapy and the extent of prostatectomy seem to be key points in the treatment of these tumours. The aim of the present study was to evaluate the pathological circumferential margin status and the local recurrence rate following different therapeutic options. METHOD: A multicentre, retrospective study was conducted of patients with rectal cancer threatening or affecting the prostatic plane, but not the bladder, judged by magnetic resonance imaging (MRI). The use of preoperative chemoradiotherapy and the type of urologic resection were correlated with the status of the pathological circumferential resection margin (CRM) and local recurrence. RESULTS: A consecutive series of 126 men with rectal cancer threatening (44) or affecting (82) the prostatic plane on preoperative staging and operated with local curative intent between 1998 and 2010 was analysed. In patients who did not have chemoradiotherapy but had a preoperative threatened anterior margin the CRM-positive rate was 25.0%. In patients who did not have preoperative chemoradiotherapy but did have an affected margin, the CRM-positive rate was 41.7%. When preoperative radiotherapy was given, the respective CRM infiltration rates were 7.1 and 20.7%. In patients having preoperative chemoradiotherapy followed by prostatic resection the rate of CRM positivity was 2.4%. Partial prostatectomy after preoperative chemoradiotherapy resulted in a free anterior CRM in all cases, but intra-operative urethral damage occurred in 36.4% of patients who underwent partial prostatectomy, resulting in a postoperative urinary fistula in 18.2% of patients. CONCLUSION: Preoperative chemoradiation is mandatory in male patients with a threatened or affected anterior circumferential margin on preoperative MRI. In patients with preoperative prostatic infiltration, prostatic resection is necessary. In this group of patients partial prostatectomy seems to be oncologically safe.


Asunto(s)
Recurrencia Local de Neoplasia/patología , Próstata/cirugía , Prostatectomía , Neoplasias del Recto/patología , Neoplasias del Recto/terapia , Fístula Urinaria/etiología , Anciano , Quimioradioterapia Adyuvante , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Terapia Neoadyuvante , Invasividad Neoplásica , Neoplasia Residual , Próstata/patología , Prostatectomía/efectos adversos , Prostatectomía/métodos , Radioterapia Adyuvante , Estudios Retrospectivos , Uretra/lesiones
5.
Arch Gerontol Geriatr ; 60(2): 294-8, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25555754

RESUMEN

OBJECTIVES: Aging, as a stage of development is marked by major changes to which the subject must adapt. Instrumental reminiscence is based on recalling times one coped with stressful circumstances, and analyzing what it took to adapt in those situations. The purpose of the present study was to analyze the effectiveness of an instrumental reminiscent program to enhance adaptive capacity (problem-focused coping and emotion-focused) and resilience in older adults. METHOD: Thirty participants noninstitutionalized conducted a pre and post assessment on a treatment consisting of the Mini-Mental State Examination (MMSE), Brief Resilient Coping Scale and Stress Coping Questionnaire (CAE). The program was developed over 8 sessions of 60 min. RESULTS: Repeated measures analysis of variance showed significant differences in time-group interaction for treatment effectiveness of resilience measures, problem-solving coping, positive reappraisal and avoidance coping that it increased, and on emotion-focused coping and overt emotional expression that gets decreased after treatment. CONCLUSION: The instrumental reminiscence has proven to be a highly useful tool and is a potentially efficient way to improve adaptive capacity and resilience in the elderly to cope with adverse situations. Through non-pharmacological therapies, the quality of life has been improved, and subjects are provided with tools, strategies and skills that allow to achieve a satisfactory adaptation.


Asunto(s)
Adaptación Psicológica , Envejecimiento/psicología , Memoria , Calidad de Vida , Resiliencia Psicológica , Estrés Psicológico/psicología , Adulto , Anciano , Anciano de 80 o más Años , Emociones , Femenino , Humanos , Masculino , Trastornos Mentales , Encuestas y Cuestionarios
6.
Colorectal Dis ; 11(5): 502-7, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18637925

RESUMEN

OBJECTIVE: To evaluate the relationship between extent of internal sphincter division following open and closed sphincterotomy, as assessed by anal endosonography, with fissure persistence/recurrence and faecal incontinence. METHOD: A total of 140 consecutive patients undergoing lateral internal sphincterotomy (LIS) for idiopathic chronic anal fissure were prospectively studied. Preoperative clinical assessment was performed together with a postoperative clinical and endosonographic examination. Three zones of the internal sphincter, identifiable by endosonography, were used to describe the uppermost extent of LIS. Primary end-points were fissure persistence/recurrence and faecal incontinence. RESULTS: A total of 140 patients, median age 49.5 years (IQR: 38-56 years) were included. Seventy-five (53.6%) and 65(46.4%) patients underwent percutaneous LIS (PLIS) and open LIS (OLIS) respectively. Median follow-up was 21 months (IQR: 14-29 months). Persistence and recurrence rates were 2.9% (4/140) and 5.7% (8/140) respectively. 7.9% (11/140) patients scored > 3 on the Jorge and Wexner Faecal Incontinence scale. PLIS was associated with a trend towards higher fissure persistence/recurrence rates than OLIS (12.0%vs 4.6%, P = 0.141). OLIS was significantly associated with a higher proportion of complete sphincterotomies (CS) than PLIS (56/65 vs 48/75, P = 0.003). A CS was associated with a lower fissure persistence or recurrence rate (1/104 vs 11/36, P < 0.001) but higher incontinence scores (11/104 vs 0/36 cases with Wexner scores > 3, P = 0.042) than following incomplete sphincterotomy. There was a strongly significant increase in incontinence scores (P < 0.001) and decrease in recurrence rates (P < 0.001) with increasing length of sphincterotomy. CONCLUSION: We recommend a short and CS using either PLIS or OLIS for the treatment of idiopathic anal fissure.


Asunto(s)
Canal Anal/cirugía , Endosonografía/métodos , Fisura Anal/cirugía , Esfinterotomía Endoscópica/métodos , Adulto , Canal Anal/diagnóstico por imagen , Incontinencia Fecal/etiología , Femenino , Fisura Anal/diagnóstico por imagen , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Recurrencia , Esfinterotomía Endoscópica/instrumentación
7.
Z Kardiol ; 90(7): 492-7, 2001 Jul.
Artículo en Alemán | MEDLINE | ID: mdl-11515279

RESUMEN

Hyperthyroidism is usually associated with tachycardia, hypothyroidism with bradycardia. After observing clinically inapparent hyperthyroidism in patients requiring pacemaker implantation, we studied the occurrence of hyperthyroidism in patients receiving a first permanent pacemaker. Of 237 patients (age 71.4 +/- 8.9 years; 54.9% females), 16 (6.75%) had subclinical (TSH < 0.1 mE/l and fT3 < or = 9.0 pmol/l) and 4 (1.69%) overt hyperthyroidism (TSH < 0.1 mE/l and fT3 > 9.0 pmol/l). Prevalence of hyperthyroidism was similar to that in the general population. Compared to euthyroid patients, in the patients with subclinical or overt hyperthyroidism there were significantly more females (n = 16) than males (n = 4; p = 0.018). Hyperthyroid patients were older (75.0 +/- 9.6 vs. 70.7 +/- 8.9 years; p = 0.015). At follow-up, all patients had a relevant proportion of pacemacer-induced beats. Clinical signs of hyperthyroidism or cardiac symptoms were not different between groups. In conclusion, bradycardia does not exclude the presence of hyperthyroidism. Temporary pacing is recommended in thyreotoxicosis with bradycardia. In contrast, primary implantation of a permanent pacemaker appears to be adequate in patients with bradycardia, cardiovascular disease and an additional diagnosis of hyperthyroidism.


Asunto(s)
Bradicardia/terapia , Hipertiroidismo/epidemiología , Marcapaso Artificial , Factores de Edad , Anciano , Bradicardia/diagnóstico , Estudios Transversales , Femenino , Humanos , Hipertiroidismo/diagnóstico , Masculino , Persona de Mediana Edad , Factores Sexuales
8.
Surg Endosc ; 14(7): 608-11, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10948294

RESUMEN

BACKGROUND: Bile duct injury (BDI) is a severe complication of laparoscopic cholecystectomy (LC) that is probably related to the effects of the learning curve. The aim of this prospective, institutional, and longitudinal study is to compare the incidence of BDI during LC in relation to the progressive experience of surgeons. METHODS: A total of 784 LC were examined during a 6-year period. They were divided into the following three consecutive groups: group A (1993-94), group B (1995-96), and group C (1997-98). Incidence and type of BDI, experience of the surgeon, intra- or postoperative diagnosis, treatment performed to repair the injury, and early and late morbidity and mortality were evaluated. RESULTS: The overall incidence of BDI was 1.4%. There were three cases of transection of the common bile duct, four partial lesions of the bile duct, and four cystic leakages. The number of BDI was maintained over the three different time periods; there were no statistical differences in the proportion of injuries among groups. Most BDI were incurred by experienced surgeons. In all, 36% of BDI were recognized intraoperatively. Hepaticojejunostomy, direct suture over a T-tube, and closure of the cystic stump were done to repair BDI. There was no additional morbidity or mortality in the patients with BDI. CONCLUSIONS: No relation was found between the experience of the surgeon and the number of BDI over the different periods of time. Therefore, BDI during LC cannot be attributed solely to the learning curve.


Asunto(s)
Conductos Biliares/lesiones , Colecistectomía Laparoscópica , Complicaciones Intraoperatorias/epidemiología , Adulto , Anciano , Competencia Clínica , Femenino , Humanos , Complicaciones Intraoperatorias/prevención & control , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Tiempo
9.
Cir. Esp. (Ed. impr.) ; 67(3): 276-280, mar. 2000.
Artículo en Es | IBECS | ID: ibc-3735

RESUMEN

Se presentan los resultados del primer estudio de consenso auspiciado por la Sociedad Valenciana de Cirugía sobre el tratamiento quirúrgico del cáncer gástrico. Se trata de un esudio tipo Delphi, con la participación de 31 expertos pertenecientes a la mayoría de hospitales de la Comunidad Valenciana. Los temas consensuados han versado sobre los siguientes aspectos: nutrición artificial, métodos de estadificación preoperatoria, tipo de resección y de linfadenectomía, técnicas de reconstrucción, criterios de resecabilidad y temas de organización (AU)


Asunto(s)
Encuestas y Cuestionarios/clasificación , Encuestas y Cuestionarios/normas , Encuestas y Cuestionarios , Técnica Delphi , Alimentación con Biberón , Alimentación con Biberón/métodos , Laparoscopía , Laparoscopía/métodos , Algoritmos , Esplenectomía , Neoplasias Gástricas/cirugía , Escisión del Ganglio Linfático , Gastrectomía , Estadificación de Neoplasias/métodos , Síndrome de Laurence-Moon/clasificación , Síndrome de Laurence-Moon/epidemiología , Síndrome de Laurence-Moon/fisiopatología
10.
Br J Clin Pharmacol ; 48(2): 223-9, 1999 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10417500

RESUMEN

AIMS: The therapeutic action of tricyclic agents may be accompanied by unwanted effects on the cardiovascular system. The evidence for the effects on vascular and nonvascular smooth muscle comes from animal studies. Whether these studies can be extrapolated to human vessels remains to be determined. Therefore, the present study was designed to investigate the influence of amitriptyline, nortriptyline and sertraline on the contractile responses of human isolated mesenteric arteries to electrical field stimulation, noradrenaline and potassium chloride. METHODS: Arterial segments (lumen diameter 0.8-1.2 mm) were obtained from portions of the human omentum during the course of 41 abdominal operations (22 men and 19 women), and rings 3 mm long were mounted in organ baths for isometric recording of tension. In some artery rings the endothelium was removed mechanically. RESULTS: In precontracted artery rings amitriptyline, nortriptyline and sertraline (3x10(-7)-10(-4) m ) produced concentration-dependent relaxation that was independent of the presence or absence of vascular endothelium. Incubation with indomethacin (3x10(-6) m ) reduced the pD2 values thus indicating the participation of dilating prostanoid substances in this response. Amitriptyline and nortriptyline inhibited both the neurogenic-and noradrenaline-induced contractions. In contrast, only the highest concentration of sertraline reduced the adrenergic responses. Amitriptyline, nortriptyline and sertraline inhibited contractions elicited by KCl and produced rightward shifts of the concentration-response curve to CaCl2 following incubation in calcium-free solution. CONCLUSIONS: These results indicate that amitriptyline and nortriptyline could act as adrenoceptor antagonists and direct inhibitors of smooth muscle contraction of human mesenteric arteries, whereas sertraline might principally exert its action only as direct inhibitor of smooth muscle contraction. This relaxant mechanism involves an interference with the entry of calcium.


Asunto(s)
Antidepresivos/farmacología , Arterias Mesentéricas/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Adulto , Anciano , Anciano de 80 o más Años , Amitriptilina/farmacología , Antidepresivos de Segunda Generación/farmacología , Antidepresivos Tricíclicos/farmacología , Estimulación Eléctrica , Femenino , Humanos , Técnicas In Vitro , Masculino , Persona de Mediana Edad , Contracción Muscular/efectos de los fármacos , Relajación Muscular/efectos de los fármacos , Nortriptilina/farmacología , Cloruro de Potasio/farmacología , Sertralina/farmacología
11.
Z Kardiol ; 86(6): 417-22, 1997 Jun.
Artículo en Alemán | MEDLINE | ID: mdl-9324871

RESUMEN

Primary chylopericardium is a rare disease with a highly variable clinical course. We report on a 24-year old female with chylopericardium detected during a pulmonary infection. Despite successful treatment of the infectious disease, the chylopericardium persisted and led to cardiac tamponade. From this case, as well as from the literature, it is intriguing to postulate an inflammatory injury of preexisting anomalous lymphatic vessels leading to onset or aggravation of primary chylopericardium. The clinical hallmark of chylopericardium is a milky white, but odorless pericardial fluid at pericardiocentesis. For cases where conservative treatment and pericardiocentesis fail, we newly introduced the method of pericardio-peritoneal shunting by a pericardial window. With postoperative reaccumulation of pericardial fluid, total parenteral nutrition followed by medium chain triglyceride diet was successfully reinitiated. This combined surgical and conservative approach was performed for the first time and may have helped to avoid the more aggressive treatment of thoracic duct ligation and resection. During 2 years of follow-up the patient was asymptomatic and had no recurrence of pericardial effusion.


Asunto(s)
Derrame Pericárdico/diagnóstico , Adulto , Taponamiento Cardíaco/diagnóstico , Taponamiento Cardíaco/etiología , Taponamiento Cardíaco/cirugía , Terapia Combinada , Diagnóstico Diferencial , Femenino , Estudios de Seguimiento , Humanos , Nutrición Parenteral Total , Derrame Pericárdico/etiología , Derrame Pericárdico/cirugía , Cuidados Posoperatorios , Recurrencia
12.
Am J Physiol ; 272(3 Pt 2): H1087-93, 1997 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9087579

RESUMEN

Vasopressin not only acts directly on blood vessels through V1-receptor stimulation but also may modulate adrenergic-mediated responses in animal experiments in vitro and in vivo. The aim of the present study was to investigate whether subpressor concentrations of vasopressin could modify the constrictor responses to norepinephrine and electrical stimulation of the perivascular nerves in human mesenteric arteries. Human mesenteric artery rings (3-3.5 mm long, 0.8-1.2 mm OD) were obtained from 38 patients undergoing abdominal operations. The arterial rings were suspended in organ bath chambers for isometric recording of tension. Vasopressin (3 x 10(-11) M) enhanced the contractions elicited by electrical stimulation at 2, 4, and 8 Hz (by 100, 100, and 72%, respectively) and produced a leftward shift of the concentration-response curves to norepinephrine (half-maximal effective concentration decreased from 2.2 x 10(-6) to 5.0 x 10(-7) M; P < 0.05) without any alteration in maximal contractions. Vasopressin also potentiated KCl- and calcium-induced contractions. The V1-receptor antagonist 1-[beta-mercapto-beta,beta-cyclopentamethylenepropionic acid-2-O-methyl-tyrosine, 8-arginine]vasopressin (10(-6) M) prevented the potentiation evoked by vasopressin in all cases. The calcium antagonist nifedipine (10(-6) M) did not affect the potentiation of electrical stimulation and norepinephrine induced by vasopressin but abolished KCl-induced contractions. The results suggest that vasopressin, in addition to its direct vasoconstrictor effect, strongly potentiates the responses to adrenergic stimulation and KCl depolarization. Both the direct and indirect effects of vasopressin appear to be mediated by V1-receptor stimulation. The amplifying effect of vasopressin on constrictor responses may be relevant in those clinical situations characterized by increased plasma vasopressin levels.


Asunto(s)
Arterias Mesentéricas/fisiología , Contracción Muscular/efectos de los fármacos , Músculo Liso Vascular/fisiología , Vasopresinas/farmacología , Adulto , Anciano , Arginina Vasopresina/análogos & derivados , Arginina Vasopresina/farmacología , Cloruro de Calcio/farmacología , Estimulación Eléctrica , Femenino , Antagonistas de Hormonas/farmacología , Humanos , Técnicas In Vitro , Masculino , Arterias Mesentéricas/efectos de los fármacos , Persona de Mediana Edad , Músculo Liso Vascular/efectos de los fármacos , Norepinefrina/farmacología , Epiplón/irrigación sanguínea , Cloruro de Potasio/farmacología
13.
Thromb Haemost ; 74(5): 1240-3, 1995 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-8607102

RESUMEN

In a prospective and randomized multicenter trial the efficacy of intermittent regional and systemic thrombolytic therapy for DVT was evaluated. 137 patients with phlebographically confirmed acute DVT above the calf region were treated with 20 mg of rt-PA for 4 h each day. Thrombolysis was applied either locally via a dorsal pedal vein of the firmly bandaged affected leg or systemically using a cubital vein. Treatment lasted for 4-7 days, and during this time unfractionated heparin was applied continuously with the dosage adjusted according to aPTT (1.5-2.0 times the normal value). A second phlebography was performed within 24 h after the end of treatment. Results were evaluated by an independent radiologist who was unaware of the treatment given. Significant thrombolytic results (e.g. lysis of more than 50% of the original thrombus and complete recanalization of all affected veins) were reached in only 1/3 of all patients. Rates of recanalization did not differ in both groups and bleeding complications occurred in 26.5%. We conclude that intermittent local or systemic application of 20 mg rt-PA seems to be ineffective in the treatment of DVT.


Asunto(s)
Tromboflebitis/tratamiento farmacológico , Activador de Tejido Plasminógeno/administración & dosificación , Adolescente , Adulto , Anciano , Femenino , Alemania , Humanos , Infusiones Intravenosas , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Proteínas Recombinantes/administración & dosificación
14.
Br J Pharmacol ; 113(2): 419-24, 1994 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-7834191

RESUMEN

1. The effects of vasopressin and deamino-8-D-arginine vasopressin (DDAVP, desmopressin) were studied in artery rings (0.8-1 mm in external diameter) obtained from portions of human omentum during the course of abdominal operations (27 patients). 2. In arterial rings under resting tension, vasopressin produced concentration-dependent, endothelium-independent contractions with an EC50 of 0.59 +/- 0.12 nM. The V1 antagonist d(CH2)5Tyr(Me)AVP (1 microM) and the mixed V1-V2 antagonist desGly-d(CH2)5D-Tyr(Et)ValAVP (0.01 microM) displaced the control curve to vasopressin to the right in a parallel manner without differences in the maximal responses. In the presence of indomethacin (1 microM) the contractile response to vasopressin was significantly increased (P < 0.01). 3. In precontracted arterial rings, previously treated with the V1 antagonist, d(CH2)5Tyr(Me)AVP (1 microM), vasopressin produced endothelium-dependent relaxation. This relaxation was reduced significantly (P < 0.05) by indomethacin (1 microM) and unaffected by the V1-V2 receptor antagonist desGly-d(CH2)5D-Tyr(Et)ValAVP (1 microM) or by NG-nitro-L-arginine methyl ester (L-NAME, 0.1 mM). 4. The selective V2 receptor agonist, DDAVP, caused endothelium-independent, concentration-dependent relaxations in precontracted arterial rings that were inhibited by the mixed V1-V2 receptor antagonist, but not by the V1 receptor antagonist or by pretreatment with indomethacin or L-NAME. 5. Results from this study suggest that vasopressin is primarily a constrictor of human mesenteric arteries by V1 receptor stimulation; vasopressin causes dilatation only during V1 receptor blockade. The relaxation appears to be mediated by the release of vasodilator prostaglandins from the endothelial cell layer and is independent of V2 receptor stimulation or release of nitric oxide. In contrast, the relaxation induced by DDAVP is largely dependent on stimulation of V2 receptors.


Asunto(s)
Desamino Arginina Vasopresina/farmacología , Músculo Liso Vascular/efectos de los fármacos , Vasopresinas/farmacología , Adulto , Arginina/análogos & derivados , Arginina/farmacología , Arginina Vasopresina/análogos & derivados , Arginina Vasopresina/farmacología , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiología , Femenino , Humanos , Técnicas In Vitro , Indometacina/farmacología , Masculino , Arterias Mesentéricas/efectos de los fármacos , Persona de Mediana Edad , Contracción Muscular/efectos de los fármacos , Relajación Muscular/efectos de los fármacos , NG-Nitroarginina Metil Éster , Óxido Nítrico/antagonistas & inhibidores , Vasopresinas/antagonistas & inhibidores
15.
Eur J Pharmacol ; 250(1): 103-7, 1993 Nov 30.
Artículo en Inglés | MEDLINE | ID: mdl-8119307

RESUMEN

The present study was designed to investigate the influence of endothelium-derived nitric oxide on the contractile responses of isolated human omental arteries to electrical field stimulation and noradrenaline. We measured isometric tension in artery rings obtained from portions of human omentum during the course of abdominal operations (32 patients). Electrical field stimulation induced frequency-dependent contractions which were abolished by tetrodotoxin (10(-6) M) and prazosin (10(-6) M), thus indicating that this effect was due to noradrenaline released from adrenergic nerves acting on alpha 1-adrenoceptors. The increases in tension induced by electrical field stimulation were of greater magnitude in arteries denuded of endothelium. NG-Nitro-L-arginine (L-NAME, 10(-4) M) potentiated the contractile response to electrical field stimulation in artery rings with endothelium but did not influence the contractile responses of endothelium-denuded arteries. The potentiation induced by L-NAME was completely reversed by L-arginine (10(-4) M), but not by D-arginine (10(-4) M). Contractile responses to noradrenaline were similar in arteries with and without endothelium. L-NAME (10(-4) M) had no significant effect on the contractile responses to noradrenaline. Our results suggest that electrical field stimulation releases endothelium-derived nitric oxide which inhibits the contractile responses of human omental arteries. The constrictor responses to noradrenaline are not modulated by the endothelium.


Asunto(s)
Arterias/efectos de los fármacos , Endotelio Vascular/fisiología , Músculo Liso Vascular/efectos de los fármacos , Óxido Nítrico/fisiología , Norepinefrina/farmacología , Vasoconstricción/efectos de los fármacos , Adulto , Anciano , Arginina/análogos & derivados , Arginina/farmacología , Arterias/fisiología , Estimulación Eléctrica , Endotelio Vascular/efectos de los fármacos , Femenino , Humanos , Técnicas In Vitro , Indometacina/farmacología , Masculino , Persona de Mediana Edad , Contracción Muscular/efectos de los fármacos , Músculo Liso Vascular/fisiología , NG-Nitroarginina Metil Éster , Óxido Nítrico/antagonistas & inhibidores , Epiplón/irrigación sanguínea , Estereoisomerismo , Tetrodotoxina/farmacología
16.
J Pharm Pharmacol ; 44(2): 105-8, 1992 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-1352808

RESUMEN

The effects of endothelin have been studied in isolated arterial segments (0.8-1 mm in external diam.) of human omental arteries obtained during the course of abdominal operations (15 patients, 7 men and 8 women). Paired segments, one normal and the other de-endothelized, were mounted for isometric recording of tension in organ baths. Endothelin produced concentration-dependent contractions with an EC50 value of 5.4 x 10(-9) M. Removal of endothelium did not affect significantly endothelin-induced contractions (EC50, 6.7 x 10(-9) M). Removal of extracellular calcium or addition of the calcium channel blocker nicardipine (10(-6) M) diminished but did not abolish responses to endothelin. These results indicate that endothelin exerts powerful contractile effects on human isolated omental arteries which are independent of the presence of an intact endothelial cell layer; this contraction cannot be explained solely by voltage-dependent calcium channels.


Asunto(s)
Endotelinas/farmacología , Epiplón/irrigación sanguínea , Vasoconstricción/efectos de los fármacos , Adulto , Anciano , Arterias , Calcio/farmacología , Canales de Calcio/efectos de los fármacos , Estimulación Eléctrica , Endotelio Vascular/fisiología , Femenino , Humanos , Técnicas In Vitro , Masculino , Persona de Mediana Edad , Contracción Muscular/efectos de los fármacos , Músculo Liso Vascular/efectos de los fármacos , Nicardipino/farmacología
17.
J Pharm Pharmacol ; 43(12): 869-70, 1991 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1687588

RESUMEN

The L-arginine analogues NG-monomethyl-L-arginine (L-NMMA, 10(-4) M) and NG-nitro-L-arginine methyl ester (L-NAME, 10(-4) M), which specifically inhibit the synthesis of nitric oxide from L-arginine, significantly reduced acetylcholine-induced endothelium-dependent relaxations in rings of human omental arteries. The inhibitory potency of L-NMMA and L-NAME was similar. Addition of L-NMMA or L-NAME to the organ bath did not induce any significant changes in the resting tension of the tissues. The effects of L-NMMA were reversed by L-arginine (3 x 10(-4) M). The L-NMMA enantiomer, D-NMMA (10(-4) M), did not influence either the basal tone of the preparation or the relaxing effects of acetylcholine. Arterial relaxations induced by sodium nitroprusside (10(-6) M) were not influenced by incubation with L-NMMA or L-NAME. These results suggest that endothelium-dependent relaxations in human omental arteries are mediated by the endogenous and substrate-specific generation of nitric oxide from L-arginine.


Asunto(s)
Arginina/análogos & derivados , Endotelio Vascular/fisiología , Músculo Liso Vascular/efectos de los fármacos , Acetilcolina/farmacología , Adulto , Anciano , Arginina/antagonistas & inhibidores , Arginina/farmacología , Arterias/efectos de los fármacos , Femenino , Humanos , Técnicas In Vitro , Masculino , Persona de Mediana Edad , Relajación Muscular/efectos de los fármacos , NG-Nitroarginina Metil Éster , Óxido Nítrico/metabolismo , Epiplón/irrigación sanguínea , Flujo Sanguíneo Regional/efectos de los fármacos , omega-N-Metilarginina
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