El bloqueo del ganglio estrellado y la atropina no afectan los cambios electrocardiograficos de la hemorragia subaracnoidea. / Stellate ganglion blockade and atropine do not affect the electrocardiographic changes of subarachnoid hemorrhage

Se informan dos pacientes con hemorragia subaracnoidea (HSA) aguda que tuvieron anormalidades llamativas de repolarizacion ventricular. El bloqueo bilateral del ganglio estrellado la administracion de atropina intravenosa y, en un paciente el propranolol intravenoso no cambiaron la morfologia de las ondas T ni el intervalo QT prolongado. Este estudio sugiere que los cambios de repolarizacion vistos en algunos pacientes con HSA son causados por anormalidades estructurales en el musculo ventricular, y que no son reflejo de un trastorno electrofisiologico inducido por la asimetria en el tono simpatico

[Arterial hypertension. Considerations on its current status in Mexico. In memory of Samuel Zajarias]. / Hipertensión arterial. Consideraciones sobre su estado actual en México. A la memoria de Samuel Zajarias.

The present article summarises statistical information about the problem of hypertension in this country making reference to international and national epidemiological works, with the purpose of evaluating the problem in community. Includes information about the clino-pathologic experience acheived at the National Institute of Cardiology of Mexico. The data is analyzed and commented from the point of view of how worth might be to study hypertension in Mexico.

[Thermodynamics and electrophysiology of the nervous system]. / Termodinámica y electrofisiología del sistema nervioso.

This study expresses a theory designed to associate the fundamental thermodynamic concepts to the electrophysiology of the nervous system. An analogy is drawn between the thermodynamic and electrical events of the myocardial cell during its mechanical phases with those thermodynamic and electrical events of the nerve cell during conduction. Although the myocardial and nerve cells are designed to perform different functions, their processes of membrane potential activation and corresponding directions of thermodynamic and entropy changes are basically the same. A thermodynamic view of nerve cell "active" potential corresponds to a passive downhill process during which the entropy of the system (nerve cell) increases. In contrast, the so called "resting" membrane potential corresponds to an active uphill process. Thus, there is a paradox because the nerve cell is thermodynamically passive during the "active" membrane potential, whereas it is thermodynamically active during the "resting" membrane potential. It is suggested that inhibition in the nervous system may be considered a thermodinamically active process. If the negentropic process fails, the result is the malfunctioning or the final destruction of the system.