RESUMEN
Although the physiological regulatory function of the gasotransmitter NO (a diatomic free radical) was discovered decades ago, NO is still in the frontline research in biomedicine. NO has been implicated in a variety of physiological and pathological processes; therefore, pharmacological modulation of NO levels in various tissues may have significant therapeutic value. NO is generated by NOS in most of cell types and by non-enzymatic reactions. Measurement of NO is technically difficult due to its rapid chemical reactions with a wide range of molecules, such as, for example, free radicals, metals, thiols, etc. Therefore, there are still several contradictory findings on the role of NO in different biological processes. In this review, we briefly discuss the major techniques suitable for measurement of NO (electron paramagnetic resonance, electrochemistry, fluorometry) and its derivatives in biological samples (nitrite/nitrate, NOS, cGMP, nitrosothiols) and discuss the advantages and disadvantages of each method. We conclude that to obtain a meaningful insight into the role of NO and NO modulator compounds in physiological or pathological processes, concomitant assessment of NO synthesis, NO content, as well as molecular targets and reaction products of NO is recommended.
Asunto(s)
Radicales Libres/metabolismo , Gasotransmisores/metabolismo , Óxido Nítrico/metabolismo , Animales , Técnicas Electroquímicas/métodos , Espectroscopía de Resonancia por Spin del Electrón/métodos , Fluorometría/métodos , Radicales Libres/análisis , Gasotransmisores/análisis , Humanos , Óxido Nítrico/análisisRESUMEN
INTRODUCTION: Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases capable of degrading extracellular matrix, including the basement membrane. MMPs are associated with various physiological processes such as morphogenesis, angiogenesis, and tissue repair. Moreover, due to the novel non-matrix related intra- and extracellular targets of MMPs, dysregulation of MMP activity has been implicated in a number of acute and chronic pathological processes, such as arthritis, acute myocardial infarction, chronic heart failure, chronic obstructive pulmonary disease, inflammation, and cancer metastasis. MMPs are considered as viable drug targets in the therapy of the above diseases. METHODS: For the development of selective MMP inhibitor molecules, reliable methods are necessary for target validation and lead development. Here, we discuss the major methods used for MMP assays, focusing on substrate zymography. We highlight some problems frequently encountered during sample preparations, electrophoresis, and data analysis of zymograms. RESULTS AND DISCUSSION: Zymography is a widely used technique to study extracellular matrix-degrading enzymes, such as MMPs, from tissue extracts, cell cultures, serum or urine. This simple and sensitive technique identifies MMPs by the degradation of their substrate and by their molecular weight and therefore helps to understand the widespread role of MMPs in different pathologies and cellular pathways.
Asunto(s)
Metaloproteinasas de la Matriz/análisis , Animales , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Transferencia Resonante de Energía de Fluorescencia , Humanos , Metaloproteinasas de la Matriz/metabolismo , Especificidad por SustratoRESUMEN
We investigated the protective effect of ischaemic preconditioning (IP) on the maintenance of coronary patency using on-line measurements of coronary pressures and blood flow in a closed-chest reperfused acute myocardial infarction (MI) model in pigs. Catheter-based 90-min occlusion followed by 60-min reperfusion of the left anterior descending coronary artery (LAD) was performed in anesthetised pigs (MI group). IP was applied (IP group) through two cycles of 5-min occlusion and 5-min reperfusion of the LAD before MI induction. Coronary patency was determined by measurements of coronary wedge pressure, collateral fractional flow reserve (FFRcoll), collateral pressure index (CPI) and absolute coronary blood flow (CBF). Inducible and constitutive nitric oxide synthase (iNOS/cNOS) activities and expressions were determined in the myocardium. Plasma levels of myeloperoxidase (MPO, index of activated leukocytes) and mean platelet volume (MPV, index of activated platelets) were measured. IP resulted in significantly lower levels of MPO (0.52 +/- 0.19 vs. 1.05 +/- 0.24 U/l, p<0.001) and MPV (9.1 +/- 0.6 vs. 9.6 +/- 1.0 fl, p=0.04), higher FFRcoll (0.17 +/- 0.05 vs. 0.04 +/- 0.05, p<0.001), CPI (0.13 +/- 0.05 vs. 0.02 +/- 0.05, p<0.001) and CBF (70.7 +/- 4.2 vs. 50.8 +/- 4.8 m/min, p<0.001) post-reperfusion as compared with the MI group. IP resulted in significantly higher cNOS activity and eNOS expression. Significant negative correlation was found between MPO and measures of coronary patency (FFRcoll, CPI and CBF) and cNOS activity. Moreover, cNOS activity correlated significantly with FFRcoll, CPI and CBF. In conclusion, IP attenuates the release of MPO and platelet activation, thereby contributing to the maintenance of vessel patency at microvascular level after reperfusion of the infarct-related artery.
Asunto(s)
Velocidad del Flujo Sanguíneo , Presión Sanguínea , Circulación Coronaria/fisiología , Precondicionamiento Isquémico Miocárdico/métodos , Animales , Microcirculación , Infarto del Miocardio/etiología , Infarto del Miocardio/fisiopatología , Peroxidasa/sangre , Activación Plaquetaria , Porcinos , Grado de Desobstrucción VascularRESUMEN
The role for peroxynitrite (ONOO(-)) in the mechanism of preconditioning is not known. Therefore, we studied effects of preconditioning and subsequent ischemia/reperfusion on myocardial ONOO(-) formation in isolated rat hearts. Hearts were subjected to a preconditioning protocol (three intermittent periods of global ischemia/reperfusion of 5 min duration each) followed by a test ischemia/reperfusion (30 min global ischemia and 15 min reperfusion). When compared to nonpreconditioned controls, preceding preconditioning improved postischemic cardiac performance and significantly decreased test ischemia/reperfusion-induced formation of free nitrotyrosine measured in the perfusate as a marker for cardiac endogenous ONOO(-) formation. During preconditioning, however, the first period of ischemia/reperfusion increased nitrotyrosine formation, which was attenuated after the third period of ischemia/reperfusion. We conclude that classic preconditioning inhibits ischemia/reperfusion-induced cardiac formation of ONOO(-) and that subsequent periods of ischemia/reperfusion result in a gradual attenuation of ischemia/reperfusion-induced ONOO(-) generation. This mechanism might be involved in ischemic adaptation of the heart.
Asunto(s)
Precondicionamiento Isquémico Miocárdico/métodos , Isquemia Miocárdica/fisiopatología , Reperfusión Miocárdica , Miocardio/metabolismo , Nitratos/metabolismo , Tirosina/análogos & derivados , Animales , Aorta , Velocidad del Flujo Sanguíneo , Técnicas In Vitro , L-Lactato Deshidrogenasa/biosíntesis , Masculino , Daño por Reperfusión Miocárdica/prevención & control , Ratas , Ratas Wistar , Factores de Tiempo , Tirosina/biosíntesis , Función Ventricular IzquierdaRESUMEN
We have assessed the relationship between reperfusion-induced ventricular fibrillation (VF) and heme oxygenase (HO) mRNA expression using northern blotting, reverse transcription-polymerase chain reaction (RT-PCR), and enzyme activity in isolated working ischemic/reperfused rat hearts. Isolated hearts were subjected to 30 min of global ischemia followed by 120 min of reperfusion. Upon reperfusion with VF, cardiac function was registered (n = 6 in each group), and HO mRNAs and enzyme activities were measured at the end of reperfusion in hearts that showed VF or did not develop VF. The expression of HO-1 mRNA (about fourfold) was observed in ischemic/reperfused nonfibrillated myocardium in comparison with the nonischemic control hearts. In those hearts when VF was developed, the expression of HO-1 mRNA was not observed in comparison with the nonischemic control myocardium. The results measured by RT-PCR and enzyme analysis support the data obtained by northern blotting. In additional studies, we decided to approach the question from a different angle. Thus, the purpose of our work was also to study the role of HO expression and enzyme activity in electrically fibrillated hearts without the ischemic/reperfused protocol. To simulate the period of 10 min of reperfusion-induced VF, hearts were electrically fibrillated, then defibrillated, and perfused for an additional 110 min, and HO-1 mRNA expression and enzyme activities were determined. Thus, electrically induced VF resulted in about 60%, 60%, and 70% reduction in HO-1 mRNA expression, RT-PCR signal intensity, and enzyme activity, respectively, compared with the nonfibrillated ischemic/reperfused group. In conclusion, our data provide evidence that the development of reperfusion-induced VF inhibits HO-1 mRNA expression and enzyme activity in both electrically fibrillated myocardium and ischemic/reperfused fibrillated hearts. The results clearly show that HO-1 mRNA expression and enzyme activity were increased in ischemic/reperfused nonfibrillated myocardium, suggesting that interventions that are able to increase HO-1 mRNA expression and enzyme activity may prevent the development of VF.
Asunto(s)
Hemo Oxigenasa (Desciclizante)/metabolismo , Daño por Reperfusión Miocárdica/enzimología , Fibrilación Ventricular/enzimología , Animales , Northern Blotting , Cartilla de ADN/química , Hemo Oxigenasa (Desciclizante)/genética , Masculino , Miocardio/enzimología , ARN Mensajero/biosíntesis , Ratas , Ratas Sprague-Dawley , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
In order to find an in vitro biochemical model for investigation of osseointegration in terms of dental implantology, the aim of the present study was to analyse the adsorption of human serum proteins to titanium dioxide. Titanium dioxide powder was suspended in human serum. After incubation and centrifugation the TiO2 with the adsorbed proteins were washed with distilled water, ethylendiaminetetraacetic acid (EDTA) supplemented with ammonium hydrogencarbonate (NH4HCO3) solution, and sodium dodecylsulphate (SDS), after centrifugation the supernatant fluid was collected and SDS polyacrylamide gel and native (Biomidi) gel electrophoresis were conducted to determine the type of the adsorbed proteins. Our results show, that albumin was adsorbed to TiO2, but it could be easily removed. The adsorption of a 94 kDa protein was much stronger than the other proteins. The method seems to be useful in the investigation of the protein adsorbing ability of differently treated titanium implant surfaces.
Asunto(s)
Proteínas Sanguíneas/metabolismo , Implantes Dentales , Oseointegración , Titanio/metabolismo , Adsorción , Proteínas Sanguíneas/farmacocinética , Electroforesis en Gel de Poliacrilamida , Humanos , Albúmina Sérica/metabolismoRESUMEN
Little is known concerning the effect of oxidative stress on the expression of antioxidative enzymes in the decompensated cardiac hypertrophy of spontaneously hypertensive rats (SHR), considered as a model of dilative cardiomyopathy in man. Superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) were characterized in isolated perfused hearts of 18 month old SHR and the age-matched normotensive control Wistar-Kyoto (WKY) rats, before and after 30 min infusion of 25 microM H(2)O(2). After infusion of H(2)O(2), aortic flow decreased in WKY from 26.2 +/- 2.2 to 16.0 +/- 0.8 ml/min (p <.05) but not in SHR (18.2 +/- 1.9 vs. 20.7 +/- 2.2 ml/min). This protection was related to the higher myocardial activities of GPx, MnSOD and CuZnSOD in SHR, compared with those of the WKY group. Although total SOD activity in the SHR fell after H(2)O(2) exposure (to 1.81 +/- 0.13 from 3.56 +/- 0.49 U/mg of protein), catalase activity increased (to 2.46 +/- 0.34 from 1.56 +/- 0.29 k min(-1)mg(-1)protein), compared with the pre-infusion period (p <.05 in each case). In additional studies, hearts were subjected to 30 min of global ischemia followed by 30 min of reperfusion. The results obtained in ischemic/reperfused hearts show the same changes in enzyme activities measured as it was observed in H(2)O(2) perfused hearts, indicating that oxidative stress is independent of the way it was induced. The higher catalase activity derived from elevated mRNA synthesis. The antioxidative system in dilative cardiomyopathic hearts of SHR is induced, probably due to episodes of oxidative stress, during the process of decompensation. This conditioning of the antioxidative potential may help overcome acute stress situations caused by reactive oxygen species in the failing myocardium.
Asunto(s)
Catalasa/genética , Regulación Enzimológica de la Expresión Génica/fisiología , Glutatión Peroxidasa/genética , Peróxido de Hidrógeno/farmacología , Hipertensión/enzimología , Miocardio/enzimología , Estrés Oxidativo , Superóxido Dismutasa/genética , Animales , Catalasa/metabolismo , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Glutatión Peroxidasa/metabolismo , Hipertensión/genética , Masculino , ARN Mensajero/genética , Ratas , Ratas Endogámicas SHR , Ratas Endogámicas WKY , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Superóxido Dismutasa/metabolismo , Transcripción Genética/efectos de los fármacosRESUMEN
The authors review the results of 1181 colorectal operations performed in a 16y period and analyze the last 8y period in which 713 colorectal operations were performed and the irradiation of primarily irresectable rectal cancer was introduced. At the time of the first operation 44% of the rectal cancer cases (69) proved to be irresectable, 14 of them were sent to a proper center as suitable ones for irradiation. 13 patients had got irradiation therapy [in three cases irradiation was combined with chemotherapy (5-fluorouracil)--synchronization chemoradiotherapy) and 11 of them were suitable for resection at the course of the second operation (there were performed 9 abdominoperineal resection and 2 Hartmann's procedures). In this small group (7% of rectal cancer cases) the radiotherapy can change the primarily irresecatable rectal cancer to resectable and for these patients this could be the only chance for cure.
Asunto(s)
Neoplasias Colorrectales/radioterapia , Neoplasias Colorrectales/cirugía , Adulto , Anciano , Antimetabolitos Antineoplásicos/uso terapéutico , Quimioterapia Adyuvante , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Femenino , Fluorouracilo/uso terapéutico , Humanos , Masculino , Persona de Mediana Edad , Radioterapia Adyuvante , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: The role of NO in the mechanism of preconditioning is not understood. Therefore, we studied the effect of preconditioning and subsequent ischemia/reperfusion on myocardial NO content in the presence of an NO synthase (NOS) inhibitor. METHODS AND RESULTS: Isolated working rat hearts were subjected to preconditioning protocols of 3 intermittent periods of rapid pacing or no-flow ischemia of 5 minutes' duration each followed by a test 30 minutes of global no-flow ischemia and 15 minutes of reperfusion. Test ischemia/reperfusion resulted in a deterioration of myocardial function and a considerable increase in cardiac NO content as assessed by electron spin resonance. Preconditioning improved postischemic myocardial function and markedly decreased test ischemia/reperfusion-induced NO accumulation. In the presence of 4.6 micromol/L N(G)-nitro-L-arginine (LNA), basal cardiac NO content decreased significantly, although test ischemia/reperfusion-induced functional deterioration and NO accumulation were not affected in nonpreconditioned hearts. However, the protective effects of preconditioning on both test ischemia/reperfusion-induced functional depression and NO accumulation were abolished. When 4.6 micromol/L LNA was administered after preconditioning, it failed to block the effect of preconditioning. In the presence of 46 micromol/L LNA, ischemia/reperfusion-induced NO accumulation was significantly decreased and postischemic myocardial function was improved in nonpreconditioned hearts. CONCLUSIONS: Our results show that (1) although NO synthesis by the heart is necessary to trigger classic preconditioning, preconditioning in turn attenuates the accumulation of NO during ischemia/reperfusion, and (2) blockade of ischemia/reperfusion-induced accumulation of cardiac NO by preconditioning or by an appropriate concentration of NOS inhibitor alleviates ischemia/reperfusion injury as demonstrated by enhanced postischemic function.
Asunto(s)
Precondicionamiento Isquémico Miocárdico , Isquemia Miocárdica/terapia , Daño por Reperfusión Miocárdica/prevención & control , Miocardio/metabolismo , Óxido Nítrico/metabolismo , Animales , Espectroscopía de Resonancia por Spin del Electrón , Inhibidores Enzimáticos/farmacología , Masculino , Óxido Nítrico Sintasa/antagonistas & inhibidores , Nitroarginina/farmacología , Ratas , Ratas WistarRESUMEN
We investigated whether the expression of heme oxygenase (HO) isozymes was related to the occurrence of ventricular fibrillation (VF) induced by ischemia/reperfusion in nondiabetic and diabetic myocardium. To study the role of HO-1 and HO-2 mRNA expression in VF, isolated hearts obtained from nondiabetic and 8-week diabetic rats were subjected to 30 min of ischemia followed by 2 h of reperfusion. Expression of HO-1 and HO-2 mRNA was studied in fibrillated and nonfibrillated myocardium using Northern blotting and reverse transcription polymerase chain reaction (RT-PCR). The effect of zinc protoporphyrin IX (Zn-PPIX), a potent inhibitor of HO activity, on HO activity was also studied in ischemic/reperfused hearts. Upon reperfusion, an expression of HO-1 was observed in nonfibrillated myocardium. HO-1 mRNA expression was significantly reduced in hearts showed VF. Zn-PPIX (5 microM) treatment reduced HO activity from its control values of 398+/-27 (in nondiabetics) and 370+/-20 pmol bilirubin/h (in diabetics) to 69+/-14 (in nondiabetics, p<.05) and 60+/-11 pmol bilirubin/h (in diabetics, p<.05), respectively, and all hearts, upon reperfusion, showed VF in both nondiabetic and diabetic subjects. HO-2 expression was unchanged in nonfibrillated and fibrillated myocardium. Postischemic function showed no correlation with the expression of these genes. Our data show that the mechanism(s) of ischemia/reperfusion-induced VF involves the downregulation of HO-1 mRNA and a reduction in HO activity. Furthermore, the mechanism(s) of VF at molecular level involving HO isozymes does not show a significant difference between nondiabetics and diabetics.
Asunto(s)
Diabetes Mellitus Experimental/enzimología , Diabetes Mellitus Experimental/fisiopatología , Corazón/fisiopatología , Hemo Oxigenasa (Desciclizante)/metabolismo , Isquemia Miocárdica/enzimología , Reperfusión Miocárdica , Miocardio/enzimología , Animales , Inhibidores Enzimáticos/farmacología , Corazón/efectos de los fármacos , Hemo Oxigenasa (Desciclizante)/antagonistas & inhibidores , Hemo Oxigenasa (Desciclizante)/genética , Hemo-Oxigenasa 1 , Isoenzimas/antagonistas & inhibidores , Isoenzimas/genética , Masculino , Protoporfirinas/farmacología , Ratas , Ratas Sprague-DawleyRESUMEN
We have previously shown that hypercholesterolemia leads to the loss of pacing-induced preconditioning (PC), possibly due to the impairment of cardiac nitric oxide (NO) synthesis. It has been shown that excess exogenous cholesterol inhibits formation of several polyprenyl derivatives involved in signal transduction. In the present study, we examined whether PC and cardiac NO synthesis are restored by treatment with the key polyprenyl product, farnesol, in cholesterol-fed rats. Rats fed 2% cholesterol-enriched/control diet for 24 weeks were given i.p. 5 microM/kg farnesol/vehicle, respectively. An hour later, hearts were isolated and prepared for 'working' perfusion, then subjected to PC/non-PC protocols of 3 intermittent periods of pacing of 5 min duration at 10 Hz, followed by a 10 min coronary occlusion to test the effect of PC. PC increased ischemic aortic flow (AF) from its control value of 15.6+/-1.5 to 27.3+/-1.7 mL/min (p < 0.05). PC was not observed in hearts obtained from hypercholesterolemic rats (AF: 15.7+/-1.2 mL/min), however, it reappeared in the farnesol-treated hypercholesterolemic group (AF: 31.8+/-3.4 mL/ min, p < 0.05). In tissue samples from the left ventricle, cholesterol-diet markedly decreased the intensity of the electron spin resonance spectra of NO obtained after in vivo spin trapping with Fe2+-diethyl-dithio-carbamate complex. Farnesol-treatment did not influence cardiac NO content in the cholesterol-fed or in the control group. These results show that the lost PC can be recaptured by farnesol-treatment in hypercholesterolemia, however, farnesol-treatment does not restore cardiac NO synthesis.
Asunto(s)
Colesterol en la Dieta/administración & dosificación , Farnesol/farmacología , Precondicionamiento Isquémico Miocárdico/métodos , Óxido Nítrico/biosíntesis , Animales , Estimulación Cardíaca Artificial , Hipercolesterolemia/metabolismo , Técnicas In Vitro , Masculino , Daño por Reperfusión Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/prevención & control , Miocardio/metabolismo , Fosfatos de Poliisoprenilo/metabolismo , Ratas , Ratas WistarRESUMEN
1. The role of nitric oxide (NO) was studied in the control of ischaemic/reperfused cardiac function and the effect of N,N,N',N'-tetrakis-[2-pyridylmethyl]-ethylenediamine (TPEN), a potent metal chelator, on the regulation of cardiac NO formation. 2. Rat isolated working hearts were subjected to 30 min ischaemia and reperfusion. The incidence of reperfusion-induced ventricular fibrillation (VF), ventricular tachycardia (VT) and the recovery of cardiac function were measured. Nitric oxide was detected by electron spin resonance (ESR) spectroscopy. 3. With 5.0, 7.5 and 10.0 mumol/L of TPEN administered prior to ischaemia, the drug produced a reduction in the incidence of VF from its control value of 100% to 25% (P < 0.05), 17% (P < 0.05) and 8% (P < 0.05), respectively. The incidence of VT followed the same pattern. 4. When TPEN was given at the moment of reperfusion, a reduction in the incidence of VF and VT was still observed. Reduction in the incidence of VF and VT was reflected in the improvement of cardiac function both in the pre- and post-ischaemic TPEN-treated groups. 5. TPEN reduced basal cardiac NO content and prevented the accumulation of NO during ischaemia/reperfusion. 6. The results show that TPEN exerts beneficial effects on postischaemic cardiac function and dysrhythmias in relation to inhibition of the accumulation of NO in ischaemic/reperfused myocardium.
Asunto(s)
Quelantes/farmacología , Etilenodiaminas/farmacología , Isquemia Miocárdica/fisiopatología , Daño por Reperfusión Miocárdica/fisiopatología , Óxido Nítrico/fisiología , Animales , Arritmias Cardíacas/fisiopatología , Electrocardiografía/efectos de los fármacos , Espectroscopía de Resonancia por Spin del Electrón , Pruebas de Función Cardíaca , Técnicas In Vitro , Masculino , Óxido Nítrico/metabolismo , Ratas , Ratas WistarRESUMEN
UNLABELLED: Among several mediators, nitric oxide (NO) and calcitonin gene-related peptide (CGRP) were suggested to be involved in the mechanism of preconditioning. We examined the possible role of the cardiac capsaicin-sensitive sensory innervation in pacing-induced preconditioning, as well as in the cardiac NO and CGRP content. Wistar rats were treated subcutaneously with capsaicin or its solvent in the sequence of 10, 30, and 50 mg/kg increasing single daily doses for 3 days to deplete neurotransmitters of the sensory innervation. Isolated hearts from both groups were then subjected to either preconditioning induced by three consecutive periods of pacing at 600 beats per minute for 5 min with 5 min interpacing periods, or time-matched non-preconditioning perfusion, followed by a 10-min coronary occlusion. NO content of left ventricular tissue samples was assayed by electron-spin resonance, and CGRP release was determined by radioimmunoassay. CGRP immunohistochemistry was also performed. In the non-preconditioned, solvent-treated group, coronary occlusion decreased cardiac output (CO) from 68.1 to 32.1 mL/min, increased left ventricular end-diastolic pressure (LVEDP) from 0.58 to 1.90 kPa, and resulted in 200 mU/min/g LDH release. Preconditioning significantly increased ischaemic CO to 42.9 mL/min (P < 0.05), decreased ischaemic LVEDP to 1.26 kPa (P < 0.05) and decreased LDH release to 47 mU/min/g (P < 0.05) in the solvent-treated group. Preconditioning did not confer protection in the capsaicin-pretreated group (ischaemic CO: 35.6 mL/min; LVEDP: 1.76 kPa; LDH 156 mU/min/g). Capsaicin-treatment markedly decreased cardiac NO content, CGRP release, and CGRP-immunoreactivity. CONCLUSIONS: (i) The presence of an intact local sensory innervation is a prerequisite to elicit pacing-induced preconditioning in the rat heart. (ii) A significant portion of cardiac basal NO content may be of neural origin. (iii) Release of NO and CGRP from capsaicin-sensitive nerves may be involved in the mechanism of pacing-induced preconditioning.
Asunto(s)
Péptido Relacionado con Gen de Calcitonina/fisiología , Capsaicina/farmacología , Estimulación Cardíaca Artificial , Corazón/fisiopatología , Isquemia Miocárdica/fisiopatología , Óxido Nítrico/fisiología , Animales , Péptido Relacionado con Gen de Calcitonina/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Corazón/efectos de los fármacos , Corazón/inervación , Inmunohistoquímica , Masculino , Isquemia Miocárdica/metabolismo , Miocardio/metabolismo , Fibras Nerviosas/metabolismo , Óxido Nítrico/metabolismo , Radioinmunoensayo , Ratas , Ratas WistarRESUMEN
We examined whether the inhibition of nitric oxide (NO) synthesis by NG-nitro-L-arginine (lNNA) abolished pacing-induced preconditioning, and if prolonged exposure to cholesterol-enriched diet led to the loss of preconditioning due to decreased cardiac NO formation. Therefore, Wistar rats fed 2% cholesterol-enriched diet or standard diet for 24 weeks were treated with a single dose of 1 mg/kg lNNA or its solvent at the end of the week 24, respectively. Isolated hearts from all groups were subjected to either preconditioning induced by three consecutive periods of pacing at 600 beats/min for 5 min, with 5-min interpacing periods, or time-matched non-preconditioning perfusion, followed by a 10-min coronary occlusion, respectively. In the control group, coronary occlusion after a non-preconditioning protocol decreased aortic flow (AF) from 45.4+/-2.4 to 15.6+/-1.5 ml/min, and resulted in a lactate dehydrogenase (LDH) release of 219+/-55 mU/min/g, however, preconditioning attenuated the consequences of coronary occlusion [AF: 27.3+/-1.7 ml/min (P<0.05); LDH: 44+/-14 mU/min/g (P<0.05)]. Preconditioning did not confer protection in the lNNA-treated (AF: 17.4+/-1.5 ml/min; LDH: 151+/-21 mU/min/g), and/or in the high-cholesterol-fed groups (AF: 15.7+/-1.2 ml/min; LDH: 168+/-22 mU/min/g). Preconditioning was preserved however, when hearts were treated with lNNA after the preconditioning protocol [AF: 29.6+/-2.2 ml/min (P<0.05); LDH: 48+/-17 mU/min/g (P<0.05)]. Both lNNA treatment and cholesterol-enriched diet markedly decreased cardiac NO content assayed by electron spin resonance spectroscopy. We conclude that NO may be involved in the triggering mechanism of pacing-induced preconditioning, the protective effect of which is blocked by sustained exposure to dietary cholesterol, possibly by influencing cardiac metabolism of NO.
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Estimulación Cardíaca Artificial , Colesterol en la Dieta/metabolismo , Precondicionamiento Isquémico Miocárdico , Miocardio/metabolismo , Óxido Nítrico/biosíntesis , Animales , Espectroscopía de Resonancia por Spin del Electrón , Inhibidores Enzimáticos/farmacología , Masculino , Óxido Nítrico Sintasa/antagonistas & inhibidores , Nitroarginina/farmacología , Ratas , Ratas WistarAsunto(s)
Isquemia Miocárdica/metabolismo , Óxido Nítrico/metabolismo , Animales , Técnicas In Vitro , Masculino , Ratas , Ratas WistarRESUMEN
The authors present the case of a 33 y old male patient. The young farmer suffered of a large Echinococcus (hydatid) cyst in the right lobe of his liver. The solution of the problem was a practically atypical right lobectomy. On the 5th postoperative day there was manifested a marked external bile fistula through the drain inserted at laparotomy, and the leakage continued until the 38th postoperative day, when after an endoscopic papillotomy the leak nearly immediately has closed. According to the authors, and some literary data published since, in cases of a postoperative external bile fistula the method of choice seems to be the EST.
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Fístula Biliar/etiología , Colangiopancreatografia Retrógrada Endoscópica , Equinococosis Hepática/cirugía , Hepatectomía/métodos , Esfinterotomía Endoscópica , Adulto , Fístula Biliar/cirugía , Colecistectomía/métodos , Humanos , Masculino , Complicaciones PosoperatoriasRESUMEN
We investigated whether nitroglycerin (NTG) was able to produce an anti-ischaemic effect in isolated working hearts of rats with vascular tolerance to NTG. Hearts isolated from tolerant and non-tolerant rats were subjected to 10 min coronary occlusion in the presence of 10(-7) M NTG and/or its solvent. NTG alleviated ischaemia-induced deterioration of cardiac function and decreased lactate dehydrogenase release whilst having no effect on coronary flow nor the area of the ischaemic zone both in hearts isolated from NTG-tolerant and non-tolerant rats. The magnitude of the effect was similar in the two groups. These results suggest that the anti-ischaemic effect of NTG involves direct myocardial mechanisms independent of its vascular action and that vascular tolerance to NTG does not affect this direct protective action.
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Corazón/efectos de los fármacos , Isquemia Miocárdica/prevención & control , Nitroglicerina/farmacología , Vasodilatadores/farmacología , Animales , Vasos Coronarios/efectos de los fármacos , Tolerancia a Medicamentos , Corazón/fisiopatología , Técnicas In Vitro , Masculino , Ratas , Ratas WistarRESUMEN
3757 elective nonmalignant biliary tract operations are evaluated retrospectively in the 17-year period from January 1, 1974 to December 31, 1990. The operations were divided into four periods according to development and frequency of intraoperative diagnostics: I. period without examinations of common bile duct (511 operations), II. selective period (848 operations), III. routine period (906 operations), IV. restricted routine period (1492 operations). The authors experienced improvement in their results if they carried out intravenous cholangiography routinely. Comparing eight characteristic factors they believe that their results are favourable if they performed intraoperative common bile duct examinations (manometry, cholangiography, flow rate measurement) in 39.6% rate and if they employed praeoperatively EST if necessary. They propose the selective intraoperative cholangiography. In the period of 39.6% intraoperative cholangiography (restricted routine period) they found common bile duct stones in 10.7%, unsuspected stones in 0.4%, retained stones in 1.6%, unnecessary choledochotomies in 2.7% and intraoperative common bile duct injuries in 0.2%. The overall mortality rate was 0.4%. They deal with the intraoperative differential diagnostics of Vater papilla stenosis and spasm.
Asunto(s)
Ampolla Hepatopancreática/cirugía , Colecistectomía Laparoscópica , Colelitiasis/cirugía , Cálculos Biliares/cirugía , Colangiografía , Colecistectomía , Colelitiasis/diagnóstico por imagen , Femenino , Cálculos Biliares/diagnóstico por imagen , Humanos , MasculinoRESUMEN
The 42 years old male patient in a 12 year period got over seven laparotomies and repeated bowel resections, due to which there was left only about 50 cm long jejunum, grossly dilatated and connected side to side to the transverse colon after a right hemicolectomy. The patients was admitted in a serious state of malnutrition due to a Y-shaped fistula formation between the too long blind end of the jejunotransversostomy and the first part of the jejunum. The blind end was resected and the 2 holes on the jejunum was closed by one layer wire stitches. The histology demonstrated a typical granulomatosis process. In summary: the Crohn's disease cannot be cured by surgical means. In this panalimentary process the repeated small bowel resections imply a later short bowel syndrome. On the base of the literature and of their modest experience the authors emphasize the need of conservative surgery and for the so called skip-lesions only stricture plasties to be performed instead of resections.
Asunto(s)
Enfermedad de Crohn/cirugía , Adulto , Colectomía/métodos , Enfermedad de Crohn/tratamiento farmacológico , Combinación de Medicamentos , Glucosamina/análogos & derivados , Glucosamina/uso terapéutico , Granuloma/patología , Humanos , Ileostomía , Íleon/patología , Yeyuno/cirugía , Masculino , Esteroides/uso terapéutico , Sulfasalazina/uso terapéuticoRESUMEN
A 62-year old woman presented a fistula due to a previously made cystojejunostomy performed because of a small pancreatic lesion considered as a pseudocyst. This intervention was performed in another institute. In the course of the exploration the authors resected the whole mass with the Roux-en-Y loop, and with the spleen. The histological examination proved a cystadenocarcinoma of the pancreas. There are discussed the problems of the intraoperative diagnosis of pancreatic lesions, and the possibilities of the reduction of mistakes. The authors emphasize the experience of the surgeon--which is the most important factor of the cure--and the importance of the fine needle biopsy.