RESUMO

En el presente estudio experimental fue realizado en condiciones fisiológicas de hipoxia:adaptación crónica de ratas 4400 m de altura simulada (HHC).En este trabajo se resumen nuestros resultados de función,histología y lipoperoxidabilidad adrenal en ratas de ambos sexos enteras y castradas.Se reiteran observaciones previa de diferencias asociadas al sexo en las respuestas a la HHC del hematocrito,el peso adrenal y el peso seco cardíaco.Los niveles circulantes de corticosterona (B) y de ácido úrico (AU) no se afectaron por HHC en ambos sexos pero si en los machos castrados en los que B disminuyó respecto de su control normóxico (p<0,001) y del animal entero(p<0,001) y el ácido úrico aumentó por HHC (p<0,05).Los machos normóxicosintactos mostraron correlación directa entre la lipoperoxidabilidad adrenal y el AU que desapareció por HHC y por castración.A pesar de estos cambios se observó que las adrenales de todos los grupos adaptados eran histológica e histoquímicamente normales,o sea en disidencia a lo propuesto por Selye de que estas glándulas se agotan ante cronicidad del estímulo.Se concluye que las hormonas esteroideas en genral participan directa e indirectamente en la respuesta fisiológica a la HHC y modulan la lipoperoxibilidad adrenal en estas condiciones experimentales

Assuntos

RESUMO

En el presente estudio experimental fue realizado en condiciones fisiológicas de hipoxia:adaptación crónica de ratas 4400 m de altura simulada (HHC).En este trabajo se resumen nuestros resultados de función,histología y lipoperoxidabilidad adrenal en ratas de ambos sexos enteras y castradas.Se reiteran observaciones previa de diferencias asociadas al sexo en las respuestas a la HHC del hematocrito,el peso adrenal y el peso seco cardíaco.Los niveles circulantes de corticosterona (B) y de ácido úrico (AU) no se afectaron por HHC en ambos sexos pero si en los machos castrados en los que B disminuyó respecto de su control normóxico (p<0,001) y del animal entero(p<0,001) y el ácido úrico aumentó por HHC (p<0,05).Los machos normóxicosintactos mostraron correlación directa entre la lipoperoxidabilidad adrenal y el AU que desapareció por HHC y por castración.A pesar de estos cambios se observó que las adrenales de todos los grupos adaptados eran histológica e histoquímicamente normales,o sea en disidencia a lo propuesto por Selye de que estas glándulas se agotan ante cronicidad del estímulo.Se concluye que las hormonas esteroideas en genral participan directa e indirectamente en la respuesta fisiológica a la HHC y modulan la lipoperoxibilidad adrenal en estas condiciones experimentales

Assuntos

RESUMO

It is not clear whether regression of cardiac hypertrophy normalizes cardiac contractility. We studied the effect of enalapril treatment on the contractile response to beta-adrenergic stimulation with isoproterenol in renal hypertension. Male Wistar rats (n = 28) were divided into a clipped group (n = 14) and control group (n = 14). Three weeks after surgery, half of the animals from each group received for 21 days either enalapril (2.5 mg/kg) twice a day or vehicle by gastric intubation. Arterial pressure and body weight were measured twice a week. At the end of the experimental period, the hearts were excised, the ventricles were weighed, and the left ventricular papillary muscle was mounted in a bath. Myocardial contractility was characterized by the maximal developed tension, the maximal rate of rise of tension (+T), and the maximal velocity of relaxation (-T), which were measured at basal conditions and after cumulative doses of isoproterenol (10(-11) to 10(-4) M). The ratio of ventricular weight to body weight increased in hypertensive rats. Enalapril induced a decrease in arterial pressure and in the cardiac mass in both treated groups (p less than 0.05). The basal values of maximal developed tension, +T, and -T were similar in the four groups. The increment in +T and -T in response to isoproterenol (10(-4) M) was depressed in the hypertensive animals and in both treated groups (p less than 0.05). There was no significant difference in the +T/-T ratio or in the ED50 among the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

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RESUMO

A retrospective study was made with the purpose of testing Ultrasound usefulness in differential diagnosis between empyematous and non empyematous evolution of parapneumonic effusions. A total of 64 patients with pneumonia and pleural effusion assisted between February 1st, 1982 and June 30th, 1989 had an Ultrasound transparietal study at the beginning and after 3 and/or 7 days of admission, with a real time equipment and a 3.5 Mhz linear transducer; they ranged between 12 and 90 years old, 27 were females and 37 males. Of these, 51 were cured by medical treatment, and 13 needed surgical drainage because of empyema evolution. The very high significant statistic signs of good prognosis in Ultrasound study were: free effusion (Table 2, p < 0.0002), maximal width less than 30 mm in sitting position (Table 1, p < 0.0001), unblurred peripleural images (Table 3, p < 0.002), and maximal homolateral diaphragmatic movement percentage more than 39% of the total (Table 4, p < 0.004); in the evolution, decrease of the maximal width effusion and slow improvement of diaphragmatic movement. Patients not included in the previous setting (31.2% of the total) were in the risk group (Fig. 1) and had loculated effusion, and/or maximal width of 30 mm or more, and/or blurred peripleural images, and/or homolateral maximal diaphragmatic movement percentage lower than 25% of the total. Less than half of this risk group was cured only with medical treatment; and they had an ultrasound evolution similar to the others cured in the same manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Assuntos

RESUMO

A retrospective study was made with the purpose of testing Ultrasound usefulness in differential diagnosis between empyematous and non empyematous evolution of parapneumonic effusions. A total of 64 patients with pneumonia and pleural effusion assisted between February 1st, 1982 and June 30th, 1989 had an Ultrasound transparietal study at the beginning and after 3 and/or 7 days of admission, with a real time equipment and a 3.5 Mhz linear transducer; they ranged between 12 and 90 years old, 27 were females and 37 males. Of these, 51 were cured by medical treatment, and 13 needed surgical drainage because of empyema evolution. The very high significant statistic signs of good prognosis in Ultrasound study were: free effusion (Table 2, p < 0.0002), maximal width less than 30 mm in sitting position (Table 1, p < 0.0001), unblurred peripleural images (Table 3, p < 0.002), and maximal homolateral diaphragmatic movement percentage more than 39

of the total (Table 4, p < 0.004); in the evolution, decrease of the maximal width effusion and slow improvement of diaphragmatic movement. Patients not included in the previous setting (31.2

of the total) were in the risk group (Fig. 1) and had loculated effusion, and/or maximal width of 30 mm or more, and/or blurred peripleural images, and/or homolateral maximal diaphragmatic movement percentage lower than 25

of the total. Less than half of this risk group was cured only with medical treatment; and they had an ultrasound evolution similar to the others cured in the same manner.(ABSTRACT TRUNCATED AT 250 WORDS)

RESUMO

A retrospective study was made with the purpose of testing Ultrasound usefulness in differential diagnosis between empyematous and non empyematous evolution of parapneumonic effusions. A total of 64 patients with pneumonia and pleural effusion assisted between February 1st, 1982 and June 30th, 1989 had an Ultrasound transparietal study at the beginning and after 3 and/or 7 days of admission, with a real time equipment and a 3.5 Mhz linear transducer; they ranged between 12 and 90 years old, 27 were females and 37 males. Of these, 51 were cured by medical treatment, and 13 needed surgical drainage because of empyema evolution. The very high significant statistic signs of good prognosis in Ultrasound study were: free effusion (Table 2, p < 0.0002), maximal width less than 30 mm in sitting position (Table 1, p < 0.0001), unblurred peripleural images (Table 3, p < 0.002), and maximal homolateral diaphragmatic movement percentage more than 39

of the total (Table 4, p < 0.004); in the evolution, decrease of the maximal width effusion and slow improvement of diaphragmatic movement. Patients not included in the previous setting (31.2

of the total) were in the risk group (Fig. 1) and had loculated effusion, and/or maximal width of 30 mm or more, and/or blurred peripleural images, and/or homolateral maximal diaphragmatic movement percentage lower than 25

of the total. Less than half of this risk group was cured only with medical treatment; and they had an ultrasound evolution similar to the others cured in the same manner.(ABSTRACT TRUNCATED AT 250 WORDS)

RESUMO

To evaluate the effect of nitrendipine on cardiac hypertrophy and inotropic response to isoproterenol in two-kidney, one-clip (2K,1C) renovascular hypertension, male Wistar rats (n = 56) were divided into a clipped group (K) (n = 28) and a sham group (S) (n = 28). Twenty-one days after surgery, the rats were placed in metabolic cages where they received either a normal diet (S and K rats) or a similar one containing N (18 mg/day) (SN and KN rats) during 3 weeks. Arterial pressure and body weight were measured twice a week. At the end of the experimental period, the hearts were excised, the ventricles were weighed, and cardiac proteins were measured by the Lowry method in seven hearts of each group. In the remaining hearts, the left ventricular papillary muscle was excised and mounted in a bath where the developed tension (dt) and the maximal rate of rise of developed tension (+T) were recorded in basal conditions, and after cumulative doses of isoproterenol (10(-11) to 10(-4) M). The arterial pressure, ventricular weight, and cardiac proteins were similar in S, SN, and KN groups and were significantly higher in the K group (p less than 0.05). No difference in the basal values of +T and dt were observed among the four groups. The increment in +T after isoproterenol was higher in treated (KN and SN) than in nontreated (K and S) groups (p less than 0.05). In conclusion, nitrendipine enhances the contractile response to isoproterenol and reverses the cardiac hypertrophy in the 2K, 1C model.

Assuntos

RESUMO

Studies in two-kidney--one clip hypertensive rats have demonstrated that long-term treatment with enalapril induced regression of cardiac hypertrophy, but the cardiac contractile response to beta-adrenergic stimulation remained depressed. In the present study, we evaluate the contractile response to beta-adrenergic stimulation of isolated papillary muscle in normal rats with isoproterenol (10(-11) M to 10(-4) M) in the presence of enalaprilic acid (10(-6) M or 10(-4) M) or enalaprilic acid (10(-4) M) and angiotensin II (10(-6) M). Myocardial contractility was characterized by maximal developed tension and maximal rate of rise of tension (+T), and the relaxant effect of isoproterenol by the ratio of (+T), and the maximal velocity of relaxation (-T)(+T/-T ratio). The rest tension (g/mm2) and the cross-sectional area (mm2) were similar in all the muscles studied. Enalaprilic acid (either 10(-6) M or 10(-4) M) in the bath did not induce any change in contractile and relaxation parameters. The increment in +T and -T (expressed as percentage) in response to cumulative doses of isoproterenol (10(-11) M to 10(-4) M) was significantly depressed in the presence of enalaprilic acid (10(-4) M) when compared with control hearts in which only vehicle was added before isoproterenol (p less than 0.05). The addition of angiotensin II after enalaprilic acid (10(-4) M) did not normalize the response in +T and -T. Enalaprilic acid diminishes the contractile response of the papillary muscle to beta-adrenergic stimulation. The inhibition of the local angiotensin II does not seem to be involved in this result.

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RESUMO

Sodium homeostasis exerts a powerful influence on the cardiovascular system in normotensive and hypertensive animals. Previous studies indicate that factors other than blood pressure can influence cardiac hypertrophy. In the present experiments, we evaluated the effects of different sodium diets in the two-kidney, one clip hypertension model in the rat. After the renal artery had been clipped, the rats received a normal sodium (177 meq/kg), high sodium (517 meq/kg), and low sodium (7 meq/kg) diet during 4 weeks. The final blood pressure was almost the same in the three groups (normal sodium 170 +/- 12 mm Hg; low sodium 168 +/- 4 mm Hg; and high sodium 162 +/- 7 mm Hg). Sodium restriction significantly reduced the development of cardiac hypertrophy as compared with rats on normal or high sodium diets. Thus, ventricular weight and ventricular weight/body weight ratio were significantly higher in rats subjected to a normal or high sodium diet (p less than 0.01). The hypertrophied hearts of rats on normal and high sodium diets showed a larger increase in the number of cardiac beta-adrenergic receptors than those observed in hearts from low sodium diet, clipped rats. These results show that sodium modulates the development of cardiac hypertrophy in two-kidney, one clip hypertensive rats. Similarly, the cardiac beta-adrenergic receptors appear to be influenced by dietary sodium intake. A possible role of the sympathetic nervous system is suggested.

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RESUMO

Previous studies from our laboratory, have demonstrated that 21 days after unclipping the decrease in arterial pressure (AP) was followed by a regression of cardiac hypertrophy (CH) and a normalization of contractile response to Isoproterenol (I) stimulation in two kidney one clip (2K1C) hypertension. The purpose in this study was to reexamine the effects of Alpha Methyl Dopa (AMD) treatment on AP, CH and cardiac response to I stimulation in this model. A total of 43 male rats, ten weeks old, were used. In 19 rats a silver clip was placed under ether anaesthesia in the left renal artery (clip group) (K). The remaining 24 animals constituted the control group (C). Twenty one days later, in 9 and in 17 animals from K and C groups, treatment with AMD 100 mg/kg/day per os was started and maintained during the three week-follow-up period (K alpha and C alpha groups). AP was measured twice a week by the tail cuff method and body weight was registered once a week. We defined hypertension when the systolic pressure was 150 mmHg or more. Three weeks after clipping and 21 days after treatment, in the clipped animals, simultaneously with matched controls (C alpha and K alpha) the cardiac response to Isoproterenol stimulation was studied. For this purpose, under pentobarbital anesthesia the carotid artery and the femoral artery and vein were cannulated in order to measure mean arterial pressure (MAP), left ventricular systolic pressure, heart rate (HR) and DP/DT+ Max in basal conditions and after I (0.001, 0.02, 0.04, 0.12 and 0.24 microgram/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

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RESUMO

Resultados previos mostraron que la hipertrofia cardíaca (HC) y la respuesta contráctil al Isoproterenol (I) en el modelo 2R Ic, se normalizagba tres semanas sdespués del descenso de la presión arterial (PA) por el declipado de la arteria renal. En el presente trabajo se estudió el efecto de la Alfa Metidopa (aMD) sobre la PA, HC y la respuesta al I. Con ese propósito, a 43 ratas macho Wistar, de 280 gramos, se las dividió en: a) Grupo Control (C) (n = 24). Luego de tres semanas de control de PA, a 17 de ellas se les administró aMD per os a la dosis de 100 mg/kg/día durante 21 días (C alta). b) Grupo clip (K) (n = 19), a los que se les colocó un clip de plata en la arteria renal izquierda. Luego de tres semanas de hipertensión a (n = 9) (K alfa) se les administró aMD en forma similar a C Alfa. La respuesta al I se evaluó a los 21 a C y K y a los 42 días a C alfa y K alfa. A tal fin, previa anestesia se canularon la carótida, la arteria y vena femorales y se registró la frecuencia cardíaca (FC), la presión arterial media (PAM), la presión sistólica y diastólica de ventrículo izquierdo y la DP/DT + MAX en condiciones basales, y luego de dosis unicas crecientes de I. Al finalizar la experiencia se determinó el peso biventricular (PC) y se normalizó por el peso corporal (pc). La PA aumentó en K (p < 0,05): 179 ñ 2,3 vs C 125 ñ 2,9 y con aMD descendió: C alfa 111 + 2,5 y K alfa 151,7 ñ 6 (p < 0,05). EIPC (g) con aMD fue menor en C alfa (p < 0,05) 0,69 ñ 0,04 vs 0,78 ñ 0,05 y en K alfa...

Assuntos

RESUMO

Previous studies from our laboratory, have demonstrated that 21 days after unclipping the decrease in arterial pressure (AP) was followed by a regression of cardiac hypertrophy (CH) and a normalization of contractile response to Isoproterenol (I) stimulation in two kidney one clip (2K1C) hypertension. The purpose in this study was to reexamine the effects of Alpha Methyl Dopa (AMD) treatment on AP, CH and cardiac response to I stimulation in this model. A total of 43 male rats, ten weeks old, were used. In 19 rats a silver clip was placed under ether anaesthesia in the left renal artery (clip group) (K). The remaining 24 animals constituted the control group (C). Twenty one days later, in 9 and in 17 animals from K and C groups, treatment with AMD 100 mg/kg/day per os was started and maintained during the three week-follow-up period (K alpha and C alpha groups). AP was measured twice a week by the tail cuff method and body weight was registered once a week. We defined hypertension when the systolic pressure was 150 mmHg or more. Three weeks after clipping and 21 days after treatment, in the clipped animals, simultaneously with matched controls (C alpha and K alpha) the cardiac response to Isoproterenol stimulation was studied. For this purpose, under pentobarbital anesthesia the carotid artery and the femoral artery and vein were cannulated in order to measure mean arterial pressure (MAP), left ventricular systolic pressure, heart rate (HR) and DP/DT+ Max in basal conditions and after I (0.001, 0.02, 0.04, 0.12 and 0.24 microgram/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

RESUMO

Resultados previos mostraron que la hipertrofia cardíaca (HC) y la respuesta contráctil al Isoproterenol (I) en el modelo 2R Ic, se normalizagba tres semanas sdespués del descenso de la presión arterial (PA) por el declipado de la arteria renal. En el presente trabajo se estudió el efecto de la Alfa Metidopa (aMD) sobre la PA, HC y la respuesta al I. Con ese propósito, a 43 ratas macho Wistar, de 280 gramos, se las dividió en: a) Grupo Control (C) (n = 24). Luego de tres semanas de control de PA, a 17 de ellas se les administró aMD per os a la dosis de 100 mg/kg/día durante 21 días (C alta). b) Grupo clip (K) (n = 19), a los que se les colocó un clip de plata en la arteria renal izquierda. Luego de tres semanas de hipertensión a (n = 9) (K alfa) se les administró aMD en forma similar a C Alfa. La respuesta al I se evaluó a los 21 a C y K y a los 42 días a C alfa y K alfa. A tal fin, previa anestesia se canularon la carótida, la arteria y vena femorales y se registró la frecuencia cardíaca (FC), la presión arterial media (PAM), la presión sistólica y diastólica de ventrículo izquierdo y la DP/DT + MAX en condiciones basales, y luego de dosis unicas crecientes de I. Al finalizar la experiencia se determinó el peso biventricular (PC) y se normalizó por el peso corporal (pc). La PA aumentó en K (p < 0,05): 179 ñ 2,3 vs C 125 ñ 2,9 y con aMD descendió: C alfa 111 + 2,5 y K alfa 151,7 ñ 6 (p < 0,05). EIPC (g) con aMD fue menor en C alfa (p < 0,05) 0,69 ñ 0,04 vs 0,78 ñ 0,05 y en K alfa...(AU)

Assuntos