RESUMEN
We have recorded control subjects, neurological and psychiatric patients (n = 217 sequences recorded over both hemispheres). Minicomputers (HP Fourier analyzer, HP 1000) for spectral analysis provided 10 spectral parameters over 5 spectral frequency bands (delta, theta, alpha, beta 1, beta 2, raw EEG). For each recorded sequence, 90 EEG maps could be computed over both hemispheres. Topo-EEGs were stored in an EEG image data bank. An EEG mapping microcomputer system linked with a digital polygraph (Alvar Electronic, REEGA 2000) has been used simultaneously. White noises have been fed into both computers for testing spatial resolution. Ten topo-EEGs have been recorded in control subjects and patients. The microcomputer system has provided very reliable topographical results when compared to similar maps generated by the minicomputer. A common average reference has been used. First clinical applications have been studied (brain strokes, brain tumors). The method appears very reliable in comparison with CT scans.
Asunto(s)
Electroencefalografía/métodos , Adulto , Análisis de Fourier , Humanos , Masculino , Microcomputadores , MinicomputadoresRESUMEN
These studies were undertaken to investigate the effect of acute bacterial infections on the absolute number of peripheral blood lymphocytes (PBL) in an elderly population and to evaluate the prognostic significance of a decreased number of PBL in critically ill aged patients. The results show that a significant lymphopenia develops in elderly patients during the course of an acute bacterial infection whereas the same type of acute illness has no effect on the PBL count of younger subjects. The lymphopenia is not related to a particular localization of the infection nor to the type of bacterial pathogen. The prognosis of the bacterial infection is closely linked to the severity of the lymphocyte depletion and its outcome can nearly be predicted by monitoring the variation of the number of circulating lymphocytes during the early course of the disease.
Asunto(s)
Envejecimiento , Infecciones Bacterianas/complicaciones , Enfermedades del Sistema Inmune/inmunología , Linfopenia/etiología , Enfermedad Aguda , Anciano , Infecciones Bacterianas/inmunología , Infecciones Bacterianas/mortalidad , Humanos , Enfermedades del Sistema Inmune/mortalidad , Recuento de Leucocitos , Linfopenia/inmunología , Linfopenia/mortalidad , Persona de Mediana Edad , Pronóstico , Estudios RetrospectivosRESUMEN
The role of the heart and its working conditions on the shape of aortic pressure curves was studied by analysis of pressure signals produced at the input of an artificial ejection circuit by 25 isolated working hearts of rats aged 4-22 months. The hearts were paced at five successive heart rates and three levels were imposed for the left auricular perfusion pressure (LAPP). With ageing of the myocardium, increased LAPP and low heart rates, there was an alteration of the pressure wave visual aspect towards a tele-systolic maximum. This modification was regularly associated with significant differences in the harmonic content of the pressure signal. More precisely, there was a bigger increase in the first harmonic amplitude than in the second and third harmonic amplitudes. Because of the physical linearity of the artificial ejection circuit and the controlled working conditions for the heart, it is possible to explain these changes in the pressure wave shape. Lowering of the heart rate is associated with an involvement of a more left part of the circuit impedance curve. Ageing of the myocardium and increased LAPP change the pressure wave shape because they were associated with an increase in left ventricular ejection time.
Asunto(s)
Envejecimiento , Corazón/fisiología , Animales , Presión Sanguínea , Gasto Cardíaco , Electrofisiología , Frecuencia Cardíaca , Técnicas In Vitro , Ratas , Función VentricularRESUMEN
The effects of age, pre-load and heart rate on the juxta-aortic pressure wave form in an artificial ejection circuit were studied in 25 isolated perfused rat hearts beating at a controlled rate. The hearts were taken from male Wistar rats aged 4, 8, 12, 16 and 22 months. Each heart was submitted to 3 pre-loads by adjusting the level of left atrium perfusion to 15, 20, 25 cm H2O. Five different heart rates (300, 240, 198, 174 and 150/min) were imposed at each level of pre-load by pacing the interatrial septum after destroying the sinoatrial node. Age, increasing pre-load and bradycardia produced similar changes in the systolic part of the wave characterised by a delayed peak. The effects of these three factors were significant and independent and corresponded to significant changes of the harmonic composition of the pressure wave. In these three conditions, the amplitude of the first harmonic of the pressure increased significantly compared with the second, third and fourth harmonics. The predominance of the amplitude of the first harmonic is characteristic of pressure waves with delayed systolic summits . The linear character of the physical properties of the circuit was tested experimentally. A change in the wave form at a fixed rate is explained by a modification of ventricular ejection which is therefore necessarily present when pre-load is increased and the age of the heart varies. On the other hand, the effect of rate changes on the wave form are explained essentially by the interplay of different zones of the impedence curve of the circuit.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Envejecimiento , Hemodinámica , Animales , Corazón/fisiopatología , Técnicas In Vitro , Masculino , Presión , Ratas , Ratas EndogámicasRESUMEN
An adaptation of the retroactive visual masking test has been developed, using a micro-computer with automation of the protocol and of the analysis of the results. The essential parameter obtained from this test is the T50 (in ms) which is the delay necessary between the letter and the mask for the subject to be able to correctly identify 50% of the letters which are presented to him. The T50 becomes shorter from childhood until adulthood, then progressively increases. It is significantly longer in elderly hospitalized subjects than in those living at home. The retroactive visual masking test can be used to evaluate the effect of physical training on the intellectual function of elderly subjects. It has good reproducibility with usually negligible learning. It is simple and inexpensive, making it a useful tool in the investigation of intellectual deterioration in the elderly.