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2.
J Hypertens ; 25(3): 679-88, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17278985

RESUMEN

OBJECTIVE: To investigate whether changes in tubuloglomerular feedback (TGF) dependent upon the tubular effects of buffering anions affect the renal haemodynamic response to L-arginine in healthy (control) individuals and patients with essential hypertension. METHODS: Mean arterial pressure (MAP), glomerular filtration rate (GFR), renal blood flow (RBF) and fractional excretion of sodium (FENa), chloride (FECl) and lithium (FELi) were measured in 10 control individuals and 10 hypertensive patients during two 3-h infusions of 0.012 mmol/kg per min L-arginine buffered with either HCl or citric acid. RESULTS: FELi, FECl and FENa increased (P < 0.001) comparably in controls and hypertensive individuals with arginine-HCl and decreased with arginine-citrate (P < 0.001). MAP was unchanged in controls with arginine-HCl and decreased by 3% with arginine-citrate (P < 0.001), and decreased in hypertensive individuals with both arginine-HCl and arginine-citrate (by 3 and 7%, respectively; P < 0.001). GFR increased with arginine-citrate in controls and hypertensive individuals (by 6.1 and 5.4%, respectively; P < 0.001), but did not change with arginine-HCl in controls and declined by 4.6% in hypertensive individuals (P < 0.05). RBF increased equally after arginine-citrate in controls and hypertensive individuals (by 34 and 33%, respectively; P < 0.001); it also increased after arginine-HCl (22 and 13%, respectively; P < 0.001), but less than after arginine-citrate (P < 0.001), and 41% less in hypertensive individuals than in controls (P < 0.001). DISCUSSION: Because arginine-HCl, unlike arginine-citrate, inhibits tubular reabsorption and elicits much less renal vasodilatation than does arginine-citrate, renal haemodynamics in response to L-arginine are modulated by changes in reabsorption and TGF according to the tubular effects of the attendant anion. As renal vasodilatation in hypertensive individuals was reduced only with arginine-HCl, which activates TGF, the blunted vasodilatation of the hypertensive kidney in response to arginine-HCl reflects an exaggerated response to an activated TGF.


Asunto(s)
Arginina/farmacología , Tasa de Filtración Glomerular/efectos de los fármacos , Hipertensión/fisiopatología , Glomérulos Renales/fisiopatología , Túbulos Renales Proximales/efectos de los fármacos , Túbulos Renales Proximales/fisiopatología , Adulto , Aniones , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Ácido Cítrico , Retroalimentación Fisiológica , Femenino , Humanos , Ácido Clorhídrico , Concentración de Iones de Hidrógeno , Glomérulos Renales/efectos de los fármacos , Túbulos Renales Proximales/irrigación sanguínea , Masculino , Tasa de Depuración Metabólica/efectos de los fármacos , Tasa de Depuración Metabólica/fisiología , Persona de Mediana Edad , Vasodilatación/efectos de los fármacos
3.
J Hypertens ; 25(2): 367-73, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17211243

RESUMEN

BACKGROUND: Rates of cardiovascular morbidity and mortality are greater in heavy alcoholics than in either teetotallers or light-to-moderate drinkers. OBJECTIVE: On the assumption that factors leading to atherosclerotic damage remain operative even after long-term alcohol withdrawal, we studied the possible mechanisms of raised cardiovascular risk in former heavy alcoholics. METHODS: Forty-two apparently disease-free, normotensive alcoholics detoxified for 37.1 +/- 31.9 (SD) months, median 24, participated in the study. They were compared with 39 lifetime alcohol-abstaining control subjects, carefully matched for age, sex, body mass index, smoking and dietary habits, physical activity, lipids and fasting glucose. Endothelial function (flow-mediated dilation of brachial artery, high-resolution ultrasound technique), blood pressure, and some parameters of endothelial activation, oxidative stress, vascular inflammation and insulin sensitivity were measured. RESULTS: The maximal percentage of flow-mediated dilatation was reduced in detoxified alcoholics (10.1 +/- 4.6 versus 14.9 +/- 7.4, P < 0.001) who also showed significantly higher blood pressure (systolic 127.5 +/- 12.9 versus 118.2 +/- 10.7 mmHg, P < 0.001; diastolic 79.4 +/- 7.1 versus 74.6 +/- 6.4 mmHg, P < 0.01; mean 95.4 +/- 8.2 versus 89.1 +/- 7.3 mmHg, P < 0.001), uric acid (5.0 +/- 1.1 versus 4.4 +/- 0.8 mg/dl, P < 0.05), high-sensitivity C-reactive protein (2.1 +/- 2.0 versus 1.0 +/- 0.9 mg/l, P < 0.01), endothelin-1 (0.38 +/- 0.11 versus 0.17 +/- 0.10 pg/ml, P < 0.001) and fasting insulin (10.4 +/- 4.5 versus 5.6 +/- 1.6 muU/ml, P < 0.001) with abnormal homeostasis model assessment index of insulin resistance (2.3 +/- 1.1 versus 1.2 +/- 0.4, P < 0.001). CONCLUSION: Previous heavy alcoholism, in spite of long-term withdrawal, is associated with endothelial dysfunction and a wide cluster of haemodynamic, vascular and metabolic abnormalities that indicate an unfavourable cardiovascular and metabolic risk profile even in apparently disease-free former alcoholics.


Asunto(s)
Alcoholismo/complicaciones , Enfermedades Cardiovasculares/fisiopatología , Endotelio Vascular/fisiopatología , Vasodilatación/fisiología , Adulto , Alcoholismo/rehabilitación , Biomarcadores/sangre , Presión Sanguínea/fisiología , Arteria Braquial/diagnóstico por imagen , Arteria Braquial/fisiología , Enfermedades Cardiovasculares/etiología , Enfermedades Cardiovasculares/prevención & control , Femenino , Humanos , Inflamación , Resistencia a la Insulina , Masculino , Persona de Mediana Edad , Estrés Oxidativo , Medición de Riesgo , Templanza , Tiempo , Ultrasonografía
4.
Surg Oncol ; 15(2): 97-106, 2006 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17123889

RESUMEN

BACKGROUND: The role of the loss of p27 protein expression in the oncogenesis of colorectal cancer is still in debate. In this study, we prospectively examined the immunohistochemical expression of p27 in 108 consecutive colorectal cancers, and we analysed the relationship with the results, the clinicopathological data, microsatellite instability (MSI) and other genetic alterations of tumours. METHODS: Unselected patients (108) who underwent curative colorectal resection for sporadic colorectal cancer in a three-year period were evaluated for MSI using 6 microsatellite markers, and for the presence of p27, p53, Fhit, Mlh1 and Msh2 proteins by means of immunostaining. The relationships between these markers were analysed. p27 protein expression was examined for association with disease recurrences and survival. RESULTS: Lack of p27 expression was noted in 33 out of 108 (30.5%) colorectal cancer cases (P<0.05). This altered expression was significantly higher in proximal cancers (P<0.05), mucinous tumours (P<0.001), poorly differentiated histology (P<0.01), cancers with MSI (P<0.05), tumours with altered expression of Mlh1 (P<0.01), of Msh2 (P<0.05), and of Fhit (P<0.01). Overall survival was better in the patient group with altered level of phenotypic p27 expression, although the difference does not reach statistical significance (P=0.069). The analysis performed only for patients with tumour at stage II showed significantly better survival when the tumour exhibited altered p27 expression (P<0.02). CONCLUSIONS: The results of the present study support the hypothesis that altered expression of p27 may be part of the genetic pathway involving MSI, which is responsible for the development of some colorectal cancers.


Asunto(s)
Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Regulación Neoplásica de la Expresión Génica , Inestabilidad de Microsatélites , Antígeno Nuclear de Célula en Proliferación/biosíntesis , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Inmunohistoquímica , Pérdida de Heterocigocidad , Masculino , Repeticiones de Microsatélite , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Resultado del Tratamiento
5.
J Investig Med ; 53(1): 26-30, 2005 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16025878

RESUMEN

An association between Graves' disease (GD) and chronic hepatitis C (C-HC) has been observed both in the presence and the absence of recombinant interferon-alpha (rIFN-alpha) treatment. rIFN-alpha-induced GD is characterized by suppressed thyroid-stimulating hormone levels; normal or elevated free triiodothyronine (FT3) and free thyroxine (FT4) values; the presence of thyroid peroxidase antibodies, antithyroglobulin antibodies, and thyroid receptor antibodies; and high iodine thyroid uptake. In contrast, GD developed during C-HC without rIFN-alpha is less clearly defined. In this study, we examined two groups of patients: group A, 28 patients with C-HC treated with rIFN-alpha who developed GD after 1 to 9 months, and group B, 10 patients with C-HC who developed GD without a previous rIFN-alpha treatment. At the time of GD, both groups started methimazole therapy; thyroid function was reevaluated after 3, 6, 9, and 12 months. Group A patients continued IFN. After 12 months, all patients of group A were euthyroid, and 21 of them (75%) had already stopped methimazole treatment, whereas all patients of group B were euthyroid and only 2 (20%) had stopped methimazole. In conclusion, the data show a better course of GD, with a more precocious and significantly higher number of recoveries in patients with rIFN-alpha-induced GD than in rIFN-alpha-unrelated disease. Further studies are needed to establish whether the two types of GD differ not only from a clinical point of view but also because of different underlying pathogenetic mechanisms.


Asunto(s)
Antivirales/uso terapéutico , Enfermedad de Graves/etiología , Hepatitis C Crónica , Interferón Tipo I/uso terapéutico , Autoanticuerpos/sangre , Femenino , Enfermedad de Graves/tratamiento farmacológico , Enfermedad de Graves/patología , Hepacivirus/clasificación , Hepacivirus/genética , Hepatitis C Crónica/complicaciones , Hepatitis C Crónica/tratamiento farmacológico , Hepatitis C Crónica/patología , Humanos , Yoduro Peroxidasa/sangre , Masculino , Metimazol/uso terapéutico , Persona de Mediana Edad , Receptores de Hormona Tiroidea/inmunología , Proteínas Recombinantes , Tirotropina/sangre , Tiroxina/análisis , Resultado del Tratamiento , Triyodotironina/análisis
6.
J Cardiovasc Electrophysiol ; 16(6): 594-600, 2005 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15946355

RESUMEN

INTRODUCTION: Simultaneous dual atrioventricular nodal conduction (SDNC) through slow (SP) and fast pathway (FP) is a rare phenomenon observed upon the induction of atrioventricular nodal reciprocating tachycardia (AVNRT). The aim of this study is to report the electrophysiological features of patients showing typical AVNRT induced through SDNC. METHODS AND RESULTS: Among 461 consecutive patients with typical AVNRT submitted to radiofrequency catheter ablation (RFCA), seven patients (1.5%) with SDNC at tachycardia onset (group I: 6 female; age 60-72 years, mean 65.2 +/- 3.8 years) and 118 age-matched controls (group II: 60 female; age 60-88 years, mean 68.4 +/- 6.8 years) were considered. Controls were further subdivided into two subgroups according to age: subgroup A (94 patients, age 60-75 years) and subgroup B (24 patients, age >75 years). The value of the following parameters was significantly higher in group I than in group II and in subgroup A: A-H interval [113 +/- 26 vs. 89 +/- 27 (P < 0.01) vs. 84 +/- 19 (P < 0.001)], ventriculoatrial conduction effective refractory period [355 +/- 85 vs. 293 +/- 87 (P < 0.05) vs. 281 +/- 82 (P < 0.05)], SP conduction time upon AVNRT induction [444 +/- 104 vs. 350 +/- 72 (P < 0.01); vs. 345 +/- 67 (P < 0.001)], AVNRT cycle length [484 +/- 103 vs. 396 +/- 71 ms (P < 0.05); vs. 384 +/- 69 (P < 0.05)], and rate of AVNRT induction from ventricle [71% vs. 10% (P = 0.001); vs. 6% (P = 0.001)]. Differences were mostly not significant between group I and subgroup B. SP location and RFCA success rate were similar in all groups. CONCLUSION: In a population of AVNRT patients, SDNC at AVNRT induction is infrequent and it prevails beyond the fifth decade of life and in females. SDNC is associated with peculiar AVN conduction features, which resemble the age-related modifications of AVN conduction.


Asunto(s)
Ablación por Catéter , Técnicas Electrofisiológicas Cardíacas , Sistema de Conducción Cardíaco/fisiopatología , Taquicardia por Reentrada en el Nodo Atrioventricular/fisiopatología , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Taquicardia por Reentrada en el Nodo Atrioventricular/diagnóstico , Factores de Tiempo
7.
Horm Res ; 63(4): 194-9, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15860921

RESUMEN

OBJECTIVE: Treatment with interferon (IFN) of patients affected by chronic hepatitis C (CH-C) may produce alterations in thyroid function, such as hypothyroidism, Graves'-like hyperthyroidism and destructive thyrotoxicosis (DT). IFN-induced DT is characterized by suppressed serum TSH levels, normal or elevated FT4 and FT3 concentrations, with the presence or absence of thyroid peroxidase antibodies and antithyroglobulin antibodies, the absence of thyroid receptor antibodies and radioactive iodine uptake suppressed or <5%. DESIGN: IFN-induced DT is a mild clinical disease, because thyroid-destructive processes last for a short time and involve a small portion of the gland. At present, the therapeutic approach in DT suggests IFN withdrawal and 1-2 months of methylprednisolone treatment. METHODS: In consideration of possible untoward side effects of steroid treatment in patients with CH-C, we studied two groups of patients with CH-C who developed DT after treatments with various preparations of recombinant IFN (with or without ribavirin). Patients sequentially entered the study during a 4-year period, at the time of DT diagnosis, when IFN therapy was discontinued. The first 12 subjects (group A) were treated with 8-16 mg/day methylprednisolone for 30-40 days after IFN withdrawal; in the following 15 patients (group B), IFN withdrawal was not followed by any additional treatment. All patients underwent clinical and laboratory controls of thyroid function at 1, 2, 3 and 6 months after DT diagnosis. RESULTS: The results showed restoration of euthyroidism in both group A and group B patients at 6 months after DT diagnosis, regardless of steroid treatment. CONCLUSIONS: The simple withdrawal of IFN therapy in patients with CH-C, who had developed DT, appears to be effective in the treatment of the thyroid disease. This therapeutic approach should be preferred in order to avoid possible undesired side effects of steroid therapy in patients with CH-C.


Asunto(s)
Antiinflamatorios/administración & dosificación , Antivirales/efectos adversos , Hepatitis C Crónica/tratamiento farmacológico , Interferón Tipo I/efectos adversos , Metilprednisolona/administración & dosificación , Tirotoxicosis/tratamiento farmacológico , Adulto , Antivirales/administración & dosificación , Femenino , Hepatitis C Crónica/sangre , Humanos , Hipotiroidismo/sangre , Hipotiroidismo/inducido químicamente , Hipotiroidismo/tratamiento farmacológico , Interferón Tipo I/administración & dosificación , Masculino , Persona de Mediana Edad , Proteínas Recombinantes , Pruebas de Función de la Tiroides , Tirotoxicosis/sangre , Tirotoxicosis/inducido químicamente , Tiroxina/sangre , Triyodotironina/sangre
8.
Alcohol Clin Exp Res ; 26(12): 1810-5, 2002 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12500104

RESUMEN

BACKGROUND: Stimulated sympathetic nervous system, renin-angiotensin-aldosterone system, vasopressin, and cortisol are thought to affect blood pressure in early withdrawal of alcoholics. Hyperactivity of sodium-retaining systems with consequent volume expansion also could interact with sodium sensitivity as previously found in long-term withdrawing alcoholics. METHODS: To investigate this hypothesis, blood pressure and sodium balance were measured during the first 8 days of withdrawal in 18 chronic alcoholics on a 150 mM Na diet. Results were related to the Salt Sensitivity Index of blood pressure as measured in the same alcoholics after 1 year of abstinence. RESULTS: Early withdrawal study: there was a positive sodium balance (+288.6 +/- 45.6 mM; p < 0.0001) and rise in mean arterial pressure (+11.8 +/- 2.9 mm Hg; p = 0.001) during early withdrawal on 150 mM Na diet. Salt Sensitivity Study after long-term detoxification: the shift from low (55 mM) to high sodium (260 mM) intake produced a larger (p = 0.04) increase in mean arterial pressure in alcoholics (+9.3 +/- 2.0 mm Hg) than in 30 teetotal controls (+5.1 +/- 1.1) (Salt Sensitivity Index, 0.047 +/- 0.008 vs. 0.023 +/- 0.0053; p < 0.05). Changes in mean blood pressure during withdrawal were highly related to sodium sensitivity index (r = 0.8; p < 0.001). CONCLUSIONS: Early withdrawing alcoholics exposed to a normal sodium intake experience positive Na balance and increase in blood pressure that is related to sodium sensitivity measured after long-term detoxification. This suggests that salt sensitivity plays a key role in blood pressure regulation in early withdrawing alcoholics.


Asunto(s)
Alcoholismo/metabolismo , Presión Sanguínea/fisiología , Sodio en la Dieta/metabolismo , Síndrome de Abstinencia a Sustancias/metabolismo , Adulto , Femenino , Humanos , Hipertensión/metabolismo , Modelos Lineales , Masculino , Persona de Mediana Edad
9.
Metabolism ; 51(8): 1022-6, 2002 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12145776

RESUMEN

The stability over a 12-year period of several coronary heart disease (CHD) risk factors was evaluated in 348 individuals who had remained healthy following baseline measurements made of the same variables in 1981. CHD risk factors evaluated were fasting and post-glucose challenge (120-minute) plasma glucose and insulin concentrations, plasma triglyceride (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) concentrations, and the ratio of LDL/HDL cholesterol concentrations. Approximately 40% to 60% of individuals in the highest CHD risk quartile (or lowest in the case of HDL cholesterol concentrations) in 1981 were still at highest risk in 1993. A similar proportion of individuals at lowest risk in 1981 were still in that category in 1993. At least 50% of the participants in this prospective analysis experienced a change by 1 quartile or more in each of the metabolic CHD risk factors measured, and these differences were highly statistically significant for all variables measured with the exception of the TG and HDL cholesterol concentrations. These results demonstrate that the implicit assumption in epidemiological studies that CHD risk factors at baseline remain stable may require examination.


Asunto(s)
Enfermedad Coronaria/etiología , Glucemia/análisis , Índice de Masa Corporal , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Humanos , Factores de Riesgo , Factores de Tiempo , Triglicéridos/sangre
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