Immunofluorescent, immunogold, and electrophoretic studies for desmin in embryonic hearts of normal and cardiac mutant Mexican axolotls, Ambystoma mexicanum.

Recessive mutant gene c for "cardiac nonfunction" in axolotls results in an absence of normal heart contractions in affected embryos due to a failure of myofibril formation. In the present study, the intermediate filament protein, desmin, is compared in developing normal and mutant hearts by means of two-dimensional gel electrophoresis, immunofluorescent microscopy, and immunoelectron microscopy. Tissues were fixed in periodate-lysine-paraformaldehyde or paraformaldehyde-glutaraldehyde solutions and rapidly frozen or embedded in Lowicryl resin. Frozen sections stained with FITC-conjugated antibodies by an indirect approach revealed that desmin is localized in the I-band regions of adult cardiac myofibrils. In normal embryonic hearts at stage 32 (preheartbeat) desmin is localized as "spots" or amorphous collections in the cells. As development progresses to stage 35, staining for desmin in normal hearts becomes more intense with localization being most pronounced at the cell peripheries. By stage 41 most of the desmin in normal hearts is localized in the I band areas of the organized myofibrils and the staining of amorphous areas is much less prominent. During early development, the distribution of desmin in mutant hearts is similar to normal. However, while most of the desmin in normal organs at stage 41 is associated with myofibrils, the staining remains diffuse in mutants. Two-dimensional gel electrophoresis reveals comparable patterns for desmin from normal and mutant hearts. Immunogold staining shows desmin localization to be between the myofibrils and around the I-band regions in adult cardiac muscle and in stage 41 normal embryonic hearts. Immunogold staining confirms a diffuse distribution of desmin in mutant hearts.

El diagnóstico electrovectocardiográfico de zona inactivable miocárdica / Electrovectocardiographic diagnosis of myocardial inactivable zone

Se subraya la importancia clínica de la exploración vectocardiográfica (alejada y espacial) del fenómeno eléctrico del miocardio, lo que constituye una integración muy útil de la exploración electrocardiográfica (cercana y analítica). Se discuten los cambios morfológicos y cronológicos más característicos debidos a una zona miocárdica inactivable, en función del proceso de despolarización ventricular. Se ilustran algunas manifestaciones electrovectocardiográficas típicas de dicha entidad patológica, subrayando el valor semiológico de los elementos complementarios que la vectocardiografía es capaz de aportar a la electrocardiografía. Ambas integran una exploración racional de la actividad eléctrica del miocardio, la que representa la base firme de las decisiones pronósticas y de la conducta terapeútica en presencia de un cuadro de infarto.

Cationic distribution in vessels, heart, skeletal muscle, and blood of normotensive (NWR) and spontaneously hypertensive rats (SHR).

Electrolytic analysis carried out with the atomic absorption spectrophotometer permitted to compare the cationic (Ca2+, Mg2+, Zn2+, K+ and Na+) tissue content of spontaneously hypertensive male rats (SHR) and normotensive male Wistar rats (NWR). In all SHR-tissues, Zn2+ is augmented, but mainly in the atria (left atrium), inferior vena cava, left ventricle, and skeletal muscle. The inferior cava vein and the right atrium have a similar, accentuated high bivalent (Ca2+, Mg2+, and Zn2+) cation content; Ca2+ and Mg2+ is present in a minor content in the right ventricle and type II "pale" skeletal muscle while only Mg2+ was also reduced in the left atrium, aorta, and the whole blood. A higher K+ concentration is seen in the right atrium, aorta, and type I "red" skeletal muscle. In the aortic wall and the whole blood a higher Na+- tissue content is found, confirming earlier observations. There is a discret water retention in the tissues from the left ventricle and skeletal muscle, simultaneously with a small depletion in the whole blood. We have concluded, that there is a specific cationic profile in SHR structural and functional different cardiovascular tissues, including skeletal muscle. The cationic tissue distribution is related to underlying genetic and adaptative factors and may be involved into specific drug effects.

Concentraçöes catiônicas no miocárdio e músculo esquelético de ratos normo e hipertensos (SHR), jovens e adultos / Cation concentrations in myocardium and skeletal muscle of normotensive rats (SHR), young and adults

Estudou-se em ratos normo (NWR) e hipertensos (SHR) jovens com idade de 14-16 semanas e adultos com 19-21semanas de idade as concentraçöes catiônicas de Mg2+, Ca2+, Zn2+ e tambem Na+ e K+ em miocárdio e músculo esquelético. As análises foram efetuadas em espectrofotômetro de absorçäo atômica. As variaçöes da distribuiçäo eletrolítica encontradas foram semelhantes no miocárdio e no músculo esquelético. As amostras obtidas de animais jovens NWR e SHR continham menor concentraçäo de cálcio, zinco e sódio e maior concentraçäo de magnésio e potássio, em comparaçäo com dados obtidos de animais adultos. A evoluçäo idade-dependente do quociente [K+]/[Na+] (maior em jovens; menor em adultos) é conseqüência de retençäo de Na+ e depleçäo de K+ e indica que possivelmente há um envolvimento (diminuiçäo?) da atividade Na+ - K+ ATPase no miocárdio em adultos (NWR e SHR). O quociente [Na+] x [K+] / [Ca2+] x [Mg2] é aumentado em animais hipertensos (SHR), principalmente no músculo esquelético, em conseqüência do aumento do produto [Na+] x [K+] em animais jovens e da reduçäo do produto [Ca2+] x [Mg2+] em animais adultos. A comparaçäo dos parâmetros entre animais normo (NWR) e hipertensos (SHR) revela que os SHRs adultos contêm mais líquido nos tecidos estudados; também no miocárdio e no músculo esquelético de SHRs foram encontradas maiores concentraçöes de zinco e menores concentraçöes de cálcio; as mesmas tendências foram observadas também em animais jovens, podendo-se, portanto, concluir que estas variaçöes säo geneticamente determinadas. A depleçäo da Na+ e K+ observada somente em miocárdio de SHRs adultos é considerada um sinal de adaptaçäo à hipertensäo, com hipertrofia ventricular, enquanto que a reduçäo de magnésio tecidual parece ser idade-dependente

Severe cardiopathy in branching enzyme deficiency.

A 7 1/2-year-old girl had exercise intolerance and exertional dyspnea. Four months later, congestive heart failure developed, with recurrent chylous pleural effusions, and she died at age 8 1/2 years. Endomyocardial biopsy tissue showed abundant PAS-positive, diastase-resistant cytoplasmic deposits. Similar inclusions were seen in muscle, skin, and liver specimens. Postmortem studies showed that the abnormal polysaccharide was especially abundant in heart and muscle, but was also present in all other tissues, including the central nervous system. Glycogen isolated from heart, muscle, and spinal cord showed a shift of the iodine spectrum toward higher than normal wavelengths. Branching enzyme activity was lacking in the muscle biopsy specimen and in all postmortem tissues; glycogenolytic enzymes had normal activities. These studies show that cardiomyopathy can be the first symptom of generalized branching enzyme deficiency and that the degree of accumulation of the abnormal polysaccharide may vary in different tissues.

[Characterization of an endogenous factor with digitalic activity in the guinea pig heart (II): Binding to a receptor]. / Caracterización de un factor endógeno con actividad digitálica en el corazón de cobayo (II): Unión al receptor.

In this work we continue the studies on the presence of an endogenous digitalis-like factor in mammals. A water extract from guinea pig heart was partially purified by liquid chromatography. The extract displaced (3H)ouabain specific binding to guinea pig heart Na,K-ATPase yielding a displacement curve parallel to that observed when digoxin was used as displacing agent. The data suggest that the activity of the extract was due to the presence of a factor that recognizes the digitalis binding site but not to ions nor lipids. Furthermore, the extract cross-reacted with antidigoxin antibodies in a manner similar to the specific antigens. These results support the hypothesis of the existence of an endogenous ligand of the digitalis receptor in mammals that could be a physiological regulator of the sodium pump.

[Characterization of an endogenous factor with digitalis-like activity in the heart of the guinea pig (I): Inhibition of Na,K-ATPase)]. / Caracterización de un factor endógeno con actividad digitálica en el corazón de cobayo (I): Inhibición de la Na,K-ATPasa.

The purpose of this work is to study the presence of an endogenous inhibitor of the sodium pump in mammals. A water extract was prepared from guinea pig heart and partially purified by liquid chromatography. The extract inhibited the activity of Na,K-ATPase but had no effect on Mg-ATPase nor on Ca-ATPase. The inhibition was similar to that produced by cardiac glycosides since it was dose-dependent, antagonised by potassium and the Na,K-ATPase prepared from brain was more sensitive than the one from heart. These results support the hypothesis on an endogenous factor exhibiting digitalis-like activity that could be a physiological regulator of the sodium pump.

Composition and dietary effects of the fish oil from "mandi" (Pinelodus clarias).

A study was carried out to determine the chemical composition and dietary effects of the oil from "mandi" (Pimelodus clarias). Findings revealed that it had a low proportion of essential C18:2 fatty acids and a high percentage of oleic acid (20.93%), as well as polyunsaturated fatty acids with more than 18 carbon atoms. Of the long-chain fatty acids, C22:6 was present in the highest percentage (1.94%). When rats were fed a diet the lipid source of which was the oil of mandi, they showed a reduced growth rate as compared to animals receiving the control diet (corn oil). The fatty acid composition of the liver and heart of rats from the experimental group was modified. The greatest variation occurred in the percentage of C22:6 in the heart muscle, wherein a five-fold increase was observed. Reduction of growth and alteration in the polyunsaturated fatty acids levels may be due to a deficiency in C18:2-w6, or to a possible imbalance between C18:2-w6 and C18:3-w3.

Changes in myocardial norepinephrine levels in response to stress, exercise and aging in control and T. cruzi-infected rats.

The effect of mild acute exercise (swimming for 1 h), restraint for 1 h and fasting for 48 h on myocardial norepinephrine concentration was compared with rats "at rest" using 320 control and chronically T. cruzi-infected rats at 50, 110, 200 and 380 days of age. Ventricular norepinephrine concentrations of control and similarly aged T. cruzi-infected rats were different for 2 of 4 "at rest" groups. Significant and opposite differences in ventricular norepinephrine were observed for restrained T. cruzi-infected rats when compared to controls (-35% in 50-day old rats and +40% in 110-day old rats). Exercised, "at rest" and fasted control rats presented a significant age-dependent decrease of ventricular norepinephrine concentration, which was not observed for restrained control rats. Norepinephrine levels of pooled atria from 120-day old "at rest" T. cruzi-infected rats were significantly lower than those from non-infected controls, whereas no difference was found in serotonin levels. The lability of myocardial norepinephrine levels in T. cruzi-infected rats suggests, but does not demonstrate, that there is a disturbance of the cardiac sympathetic control.

Avaliaçäo experimental das variaçöes dos níveis de glicogênio, lípides totais, triglicérides e água no miocárdio submetido a parada anóxica hipotérmica / Experimental evaluation of the variations of glycogen, total lipids, triglycerides and water levels in the myocardium subjected to anoxic hypothermic arrest

Analisam-se as variaçöes tissulares miocárdicas de glicogênio, lípides, triglicérides e teores de água que ocorreram em dois grupos de cäes submetidos a parada cardíaca anóxica sob circulaçäo extracorpórea, respectivamente em normotermia e hipotermia sistêmica de 28-C. Houve quedas dos níveis de glicogênio nos dois grupos sem diferenças significativas entre eles. Os níveis miocárdicos de lípideos totais apresentaram-se relativamente estáveis nos cäes a 28-C e apresentaram quedas expressivas no grupo sob normotermia. Os níveis de triglicérides mantiveram-se relativamente estáveis nos primeiros 30 minutos de anóxia, apresentando a partir daí quedas expressivas. Os teores de água decresceram em ambos os grupos, particularmente nos cäes operados sob normotermia

[Myocardial beta adrenergic receptors in experimental renal hypertension, type Goldblatt II]. / Receptores beta adrenérgicos miocárdicos durante el desarrollo de la hipertensión renal experimental, tipo Goldblatt II.

Properties of cardiac beta-adrenergic receptors from two kidney-one clip hypertension and control rats were studied to determine whether or not alterations in the receptor contribute to the decreased responsiveness of two kidney-one clip rat hearts to adrenergic stimulation. The number and affinity of the beta-receptors were assessed by the binding of [3H]DHA in an enriched ventricular membrane fraction obtained from the rat hearts 3 and 4 weeks after the application of the clip. In the rats with 3 weeks of development of hypertension no significant difference was found neither in the number nor in the affinity of receptors (30.9 +/- 5.3 fmol/mg protein, KD: 1.62 +/- 0.43 nM) compared to the control rats (33.3 +/- 6.3 fmol/mg protein, KD: 2.21 +/- 0.59 nM). In rats with 4 weeks of development of hypertension, there was an increased number of receptors (54.7 +/- 3.7 fmol/mg protein, KD: 1.41 +/- 0.17 nM) compared with control rats studied in paralleled conditions (40.0 +/- 2.3 fmol/mg protein, KD: 1.13 +/- 0.12 nM). These results suggest that the reported beta-adrenergic subsensitivity in this model of hypertensive rats could be mediated by a biochemical mechanism other than a direct alteration of the beta adrenergic receptors, and that there is a compensatory increase in the density of receptors during the development of the hypertension.

Quantification of tropomyosin by radioimmunoassay in developing hearts of cardiac mutant axolotls, Ambystoma mexicanum.

Recessive mutant gene c in axolotls results in a failure of embryonic heart function. Earlier morphological studies showed that the mutant myocardial cells lack organized sarcomeric myofibrils. Electrophoresis and immunofluorescent studies suggested that the mutant heart cells contain substantial amounts of actin, myosin and alpha-actinin; however, tropomyosin appeared deficient. In the present study, we employed a newly developed extremely sensitive solid-phase radioimmunoassay method to quantitate very accurately the tropomyosin levels in normal and mutant sibling hearts at early (stage 35), intermediate (stage 39) and late (stage 41) developmental stages. Our results demonstrate that cardiac mutant hearts contain significantly lower than normal quantities of antigenically detectable tropomyosin at all of the developmental stages examined. This insufficiency of tropomyosin in mutant hearts may be a primary cause at the cell level for their failure to form organized myofibrils.