RESUMO
The electrical impedance of isolated chick and toad retinas were measured in the absence of, and during, spreading depression, using sinusoidal measuring currents ranging from 10 to 50,000 Hz. Data obtained in the absence of the reaction indicate an electric heterogeneity of the tissue and suggest that at least two groups of cells are responsible for the observed frequency distribution. Spreading depression is accompanied by impedance changes that depend on the frequency of the measuring current and composition of the Ringer's solution. In chick retinas immersed in standard solution, impedance magnitude (Z) as well as phase angle (0) change in phase, displaying an initial increase followed by a longer decrease; in the toad, these changes depend on the measuring frequency: at 10 Hz they are similar to the ones observed in chick retinas, whereas at intermediate and high frequencies they are out of phase. In low Cl- + sucrose Ringer's solution a decrease of impedance is observed in both chick and toad retinas. In low Cl- + Na2SO4 + sucrose Ringer's solution a decrease of impedance also predominates but the Z and 0 curves are biphasic and complex, having time courses which are frequency-dependent. In addition, these changes are different in chick and toad preparations. The experiments show that the impedance changes during the retinal reaction might be related both to extracellular as well as cellular currents. The extracellular current changes could be due to decrease of ionic content and volume of extracellular space, the latter variations being drastically reduced when retinas are immersed in low Cl- solutions. The results also suggest changes of current flow through cellular components which are frequency-dependent: at low frequencies the preferential path being probably through neuronal, and at high frequencies, through glial cells.
Assuntos
Depressão Alastrante da Atividade Elétrica Cortical , Retina/fisiologia , Animais , Anuros , Galinhas , Cloretos/farmacologia , Condutividade Elétrica , Soluções Isotônicas/farmacologia , Retina/efeitos dos fármacos , Solução de RingerRESUMO
The CARE study showed that the myocardial infarction recurrence rate in patients with moderate cholesterol blood level decreases early during pravastatin treatment. Our goal is to evaluate the possible role of pravastatin in preventing the myocardial lesions induced by cold stress. Twenty Wistar-EPM rats were divided into four groups: Control (CON); PR (Pravastatin) treated with 10 mg/kg/d for 15 days; S (Stress group) in which the rats were submitted to cold stress (-8 degrees C for four hours); and PR + S group treated with pravastatin like PR group and also submitted to the cold stress. The animals were sacrificed and heart fragments were removed for optic and electronic microscopic analysis. The variable considered was mitochondria abnormality (edema, lyses and vacuolization) that was interpreted as crystolyses indices (CI) (n degree of abnormal mitochondria/n degree total of mitochondria). The following crystolyses indices, were found for each group respectively: CON, 2.0%; S, 95.5%; PR, 19.9% and PR + S group, 27.7%*(*p < 0.01). In conclusion, pravastatin prevented myocardial lesions induced by cold stress significantly.
Assuntos
Anticolesterolemiantes/uso terapêutico , Temperatura Baixa , Coração/efeitos dos fármacos , Pravastatina/uso terapêutico , Estresse Fisiológico/tratamento farmacológico , Animais , Colesterol/sangue , Masculino , Microscopia Eletrônica , Infarto do Miocárdio/sangue , Infarto do Miocárdio/prevenção & controle , Miocárdio/ultraestrutura , Ratos , Ratos Wistar , RecidivaRESUMO
OBJECTIVES: We wished to verify the possible protective action of spironolactone (SPIRO), through its blocking action of slow calcium channels, in what concerns behavioural, morphologic, histochemical and ultrastructural alterations caused by experimental exposure to hydralazine (HZ), due to the excess release of catecholamines and the cellular influx of calcium. MATERIAL AND METHODS: Forty-eight adult male Wistar rats [correction of mice] were divided into 4 groups. The control group (CON) was administered olive oil for 4 days and distilled water i.v. on the last day, the hydralazine group (HZ) was administered olive oil for 4 days and 40 mg/kg i.v. of hydralazine on the last day; the spironolactone group (SPIRO) was administered 20 mg/kg of spironolactone diluted in olive oil for 4 days and distilled water on the last day; and the hydralazine with spironolactone group (HZ + SPIRO) was administered 20 mg/kg of spironolactone diluted in olive oil for 4 days and 40 mg/kg i.v. of hydralazine on the last day. The rats [correction of mice] were dissected and fragments of the myocardium removed for electron microscopy, and suprarenal fragments removed for light microscopy. Mitochondrial alterations characterised by ridge edema, lysis and vacuolisation (Cristolysis rate = damaged mitochondria/total mitochondria) were considered in the ultrastructural study. RESULTS: Light microscopy of the HZ group showed intense depletion of lipids in the cortical region of the suprarenals. The HZ + SPIRO group did not present significant alterations and was similar in appearance to the CON group. The ultrastructural study of the myocardium revealed the following rates of Cristolysis: CON group = 5.8%, HZ group = 91.9%, SPIRO group = 10.9%, HZ + SPIRO group = 10.2%*. (* = p < 0.001 chi-square test). CONCLUSION: The use of spironolactone in a model of stress induced by hydralazine caused: 1. Myocardial protection shown by reduced lesion of cardiomyocytes; 2. Protection of the suprarenals.
Assuntos
Coração/efeitos dos fármacos , Antagonistas de Receptores de Mineralocorticoides/uso terapêutico , Miocárdio/ultraestrutura , Espironolactona/uso terapêutico , Estresse Fisiológico/prevenção & controle , Glândulas Suprarrenais/efeitos dos fármacos , Glândulas Suprarrenais/patologia , Animais , Anti-Hipertensivos , Avaliação Pré-Clínica de Medicamentos , Hidralazina , Masculino , Ratos , Ratos Wistar , Estresse Fisiológico/induzido quimicamente , Estresse Fisiológico/patologiaRESUMO
PURPOSE: To evaluate the myocardial protective effect of enalaprilat in rats submitted to stress by cold. METHODS: Fifteen adults, male rats were studied. They were allocated into four groups: group A received unrestricted diet + intraperitoneal (IP) diluent; group B: unrestricted diet + IP enalaprilat 1.0 mg/kg; group C: high salt diet (HD) for seven days + IP indomethacin 1.0 mg/kg and group D received high salt diet for seven days + IP indomethacin 1.0 mg/kg + IP enalaprilat 1.0 mg/kg. Three animals were the control group. The animals of the groups A, B, C and D were then submitted to stress by cold. Fragments of the left ventricle were obtained for electron microscopy and the occurrence of mitochondrial lysis or preservation of the mitochondrial ultrastructure were considered as parameter for myocardial protective effect evaluation. RESULTS: Crystolysis (partial or total) was observed in 16.2% group A; 19.5% of group C; 3.2% of group B and in 8.8% of group D. CONCLUSION: Enalaprilat protects the cardiomyocyte from the stress by cold.
Assuntos
Temperatura Baixa/efeitos adversos , Enalapril/farmacologia , Mitocôndrias Cardíacas/ultraestrutura , Miocárdio , Estresse Fisiológico/etiologia , Animais , Masculino , Mitocôndrias Cardíacas/efeitos dos fármacos , Ratos , Estresse Fisiológico/complicaçõesRESUMO
A man (46 years-old) was admitted to the intensive care unit (ICU) with a history that eight hours before he had voluntarily drank 100 ml of malathion. He complained of a burning pain on the anterior thorax and was confused. His cardiovascular evaluation was normal and his breathing was heavy with some rales on the pulmonary auscultation. He was treated with atropine and contrathion and rapidly evolved into coma. Electrocardiogram showed subendocardial lesion in the inferior wall with diffuse ly altered ventricular repolarization and increase QT interval. During the ICU period his cardiac enzyme levels also raised. The patient died in the 8th day after admission. The pathological evaluation of the heart revealed foci of myocardial necrosis. This is the 1st case of medical literature with histological confirmation of myocardial necrosis from organophosphate intoxication.
Assuntos
Inseticidas/intoxicação , Miocárdio/patologia , Compostos Organotiofosforados , Humanos , Masculino , Pessoa de Meia-Idade , NecroseRESUMO
Beginning with a patient presenting with an atrial septal defect (ASD) of the secundum type, the genealogy was identified in four affected individuals who belonged to three successive generations of the same family. The defects were visually confirmed in all individuals and were found to be anatomically similar. No other congenital malformations were present in these individuals. The genealogy was identified in 1972, when ASD recurred in two generations, and it was concluded that the mechanism of transmission was autosomal recessive. The fifth individual, identified 21 years later, and having an anomaly identical to that of the others, was the child of a couple who had no consaguinity and whose mother was a member of the previously studied genealogy. Considering the absence of phenotype in the parents and the rarity of the ASD gene in the general population, the occurrence of the uniparental disomy for this family nucleus, and the same autosomal recessive mechanism of transmission by this affected individual is possible. This study reports the familial occurrence of ASD by genetic mechanisms of transmission, emphasizing the necessity for genetic-clinical studies in members of the familial nucleus in order to detect new carriers, who usually are asymptomatic, thereby allowing for early and adequate treatment of individuals who may be affected.
Assuntos
Comunicação Interatrial/genética , Feminino , Humanos , Masculino , LinhagemRESUMO
Authors report a case of a patient with abdominal pheochromocytoma who presented recurrent episodes of acute pulmonary edema. No cardiopathy was detected either by clinical examination or by electrocardiogram, echograms or invasive cineventricleangiograma. They concluded that a non cardiogenic etiology is possible for the referred clinical manifestations.
Assuntos
Neoplasias Abdominais/complicações , Feocromocitoma/complicações , Edema Pulmonar/etiologia , Neoplasias Abdominais/diagnóstico por imagem , Adulto , Eletrocardiografia , Feminino , Humanos , Feocromocitoma/diagnóstico por imagem , Edema Pulmonar/diagnóstico por imagem , RadiografiaRESUMO
PURPOSE: To evaluate whether the enalaprilat, angiotensin I enzyme conversion inhibitor, could prevent the left ventricular hypertrophy (LVH) induced by isoproterenol. METHODS: Seventy two adult Wistar-EPM rats were divided into four groups: CON, control; ENA, treated with enalaprilat (1 mg/kg via subcutaneous (s.c.) for 8 days); ISO, treated with isoproterenol (0.3 mg via s.c. for 8 days) e ENA + ISO, treated with both drugs simultaneously. Each group had the arterial blood pressure, cardiac rate and the left ventricle (LV) weight determined in 10 animals. In 8 animals from each group a small sample was taken from the LV and stained with hematoxyline-eosine and picrosirius for morphometric and ultra-structural studies with optic and transmission electronic microscopy. RESULTS: The ISO group showed that the LV weight increased 47% in comparison with control. On the other hand the ENA + ISO group showed only 22.1% increase (p < or = 0.05). The morphometric and ultra-structural analyses revealed that isoproterenol induced cardiomyocite hypertrophy and augmented the content of the type I collagen in the cardiac interstitium. CONCLUSION: Enalaprilat inhibited the isoproterenol action on the cardiomyocite, avoiding partially the LVH and decreasing the content of collagen fibers.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Enalaprilato/uso terapêutico , Hipertrofia Ventricular Esquerda/induzido quimicamente , Hipertrofia Ventricular Esquerda/prevenção & controle , Isoproterenol/efeitos adversos , Animais , Hipertrofia Ventricular Esquerda/patologia , Masculino , Miocárdio/patologia , Ratos , Ratos WistarAssuntos
Enalapril/uso terapêutico , Hipertrofia Ventricular Esquerda/prevenção & controle , Análise de Variância , Animais , Avaliação Pré-Clínica de Medicamentos , Hipertrofia Ventricular Esquerda/induzido quimicamente , Isoproterenol , Masculino , Ratos , Estatísticas não Paramétricas , Fatores de TempoAssuntos
Hipertrofia Ventricular Esquerda/patologia , Região Organizadora do Nucléolo/ultraestrutura , Análise de Variância , Animais , Cardiotônicos , Hipertrofia Ventricular Esquerda/induzido quimicamente , Hipertrofia Ventricular Esquerda/metabolismo , Isoproterenol , Masculino , Miocárdio/metabolismo , Miocárdio/ultraestrutura , Região Organizadora do Nucléolo/metabolismo , Ratos , Ratos WistarAssuntos
Angiografia/métodos , Neoplasias Cardíacas/diagnóstico , Mixoma/diagnóstico , Difosfatos , Ecocardiografia , Átrios do Coração , Neoplasias Cardíacas/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Mixoma/diagnóstico por imagem , Cintilografia , Tecnécio , Pirofosfato de Tecnécio Tc 99mRESUMO
1. Extracellular pH (pHo) was measured in the cerebellar cortex of the rat using a recently developed liquid membrane ion-selective micropipette (ISM). pHo was determined during stimulus-evoked neuronal activity, elevated extracellular potassium concentration, [K+]o, spreading depression (SD), and complete ischemia. In many experiments [K+]o was simultaneously determined. 2. A train of local surface stimuli (LOC) produced an initial alkaline shift in pHo from a base line of 7.20-7.30 to 7.25-7.35. This was followed by a long-lasting acid phase that reached a plateau of 7.05-7.15 after 64 s of stimulation. pHo decrease was related to stimulus frequency, intensity, and duration. 3. Superfusion with Ringer solution containing manganese ions rapidly abolished parallel fiber-induced Purkinje cell synaptic depolarization together with the alkaline shifts while enhancing the acid shifts. 4. Superfusion of the cerebellar cortex with Ringer solution containing increasingly elevated [K+] progressively lowered pHo to a plateau of 6.95-7.05. The acidification occurred in the presence of ouabain but was reversed on return to the normal [K+]o or with the addition of the glycolytic blocker, fluoride. Stimulus-evoked alkaline shifts were enhanced by K+-Ringer superfusion. These experiments suggested that the acid shift was due to the metabolic production of an anion, possibly lactate. 5. Elevation of [K+]o above 8-12 mM often produced oscillation in pHo and [K+]o with a period of about 40 s. Sometimes these oscillations ended in a spontaneous SD or SD could be evoked by stimulation. Under these conditions of raised [K+]o, the SD consisted of a very pronounced alkaline transient followed by a small, long-lasting acid shift. When SD was induced by conditioning the cerebellum with proprionate or lowered NaCl, the alkaline phase was reduced and the acid enhanced. 6. Complete ischemia began with a progressive decrease of pHo and rise in [K+]o. When [K+]o reached 12 mM, a second more rapid rise in [K+]o to 40 mM or more occurred. This was correlated with 0.1-0.2 pHo transient increase similar to that seen during SD. pHo eventually reached a plateau of 6.60-6.80, close to neutrality. 7. Superfusion with Ringer solution containing acetazolamide immediately altered pHo homeostasis by increasing base-line pHo by about 0.10 and enhanced the induced pHo changes. These results suggest that carbonic anhydrase (CA) is important for acute buffering of the brain extracellular microenvironment. 8. The above results were interpreted in terms of changes in extracellular strong ion concentration differences ( [SID]o), extracellular concentration of total weak acid ( [Atot]o) and partial pressure of CO2 (Pco2) in the brain microenvironment. The results indicate that neuronal activity produces changes in many of the constituents of the microenvironment.
Assuntos
Equilíbrio Ácido-Base , Cerebelo/fisiologia , Espaço Extracelular/fisiologia , Acetazolamida/farmacologia , Animais , Depressão Alastrante da Atividade Elétrica Cortical , Potenciais Evocados , Feminino , Concentração de Íons de Hidrogênio , Isquemia/fisiopatologia , Manganês/farmacologia , Potássio/farmacologia , Ratos , Ratos EndogâmicosRESUMO
1. Isolated spinal cord of amphibians is able to express Leão's spreading depression (SD). 2. SD can be evoked when the spinal cord is in an appropriated medium. There are two conditions that favor its elicitation: hypotonicity and low [Cl-] levels in the extracellular microenvironment. 3. Spinal cord SD is accompanied by a stereotyped negative extracellular voltage transient of 17.3 +/- 4.9 (standard deviation) mV amplitude and 1.2 +/- 0.5 min duration concomitantly with a reversible [K+]o increase up to 21.1 +/- 4.6 mM in the extracellular fluid. 4. Potassium salt solution can trigger SD waves that spread at 12 +/- 4.7 mm/min. 5. SD waves occur "spontaneously" in preparations superfused by Ringer solutions with very low [Cl-] (< 20 mM). The frequency of these waves decreases, and they may stop if [Mg2+] is increased.