Algunas nefropatias tubulointersticiales (I) / Some tubule interstitial nephropaties (I)

Las lesiones tubulares e intersticiales capaces de producir una insuficiencia renal importante se originan siempre en multiples factores. La simple supresion de los agentes causales, a veces subestimados en la medicina corriente, garantiza muy a menudo una curacion notoria y rapida

[Pulmonary oxygen transfer under a respirator in anesthesia and resuscitation]. / Transfert pulmonaire de l'oxygène sous respirateur en anesthésie et en réanimation.

The resistance of the passage of oxygen from air to blood is estimated in measuring P(A-a)O2. This index varies with FIO2. P(a/A)O2, the index proposed by GILBERT and KEIGHLEY [18], expresses PaO2 as a percentage of PAO2. This index would be independent of FIO2. Two groups are studied. Patients of the first group (n = 22) are artificially ventilated in intensive care for severe parenchymal lesion. Those of the second group (n = 25) have no notable history of pulmonary disease and are anaesthetized and hooked up to a respiratory for surgery. Blood gases are measured and the transfer indices calculated for increasing FIO2 (0.4, 0.6, 0.8 and 1). Under conditions of anaesthesia, the effect of thermic decrease on PaCO2 is dampened by maintaining a constant PACO2 during measurement. P(a/A)O2 does not vary significantly as a function of FIO2 in the intensive care group, whereas the results observed in the anaesthetized patients are substantially dispersed. Factors which are susceptible to affect oxygen transfer as well as the effects of FIO2 increase are discussed. P(a/A)O2 stability observed in intensive care is probably related to the predominant effect of venous admixture, which is hardly affected by variations in FIO2. In anaesthesia, resistance to the transfer of oxygen appears to be linked mainly to changes in the distribution of the ventilation/perfusion ratio (reduction in CRF; pharmacological effect of oxygen on pulmonary vascular reactivity). These phenomena lead to alveolar instability and a variable shunt effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Vagal inhibitory effects on peripheral circulation in acute coronary occlusion.

The reflex adjustments of the peripheral circulation in response to acute coronary occlusion were studied in anesthetized dogs with isolated vascular beds perfused at constant flow. Coronary occlusion caused significant increases in perfusion pressure which averaged 27 +/- 4 mmHg in the hindlimb, 19 +/- 8 mmHg in skeletal muscle, and 13 + 5 mmHg in the mesenteric artery. These responses were less than half those caused by a similar decrease in aortic pressure obtained with hemorrhage. Coronary occlusion caused no significant changes in renal and paw circulations, while marked vasoconstriction resulted from hemorrhage. When aortic pressure was maintained constant throughout the duration of coronary occlusion, there was a significant vasodilatation in all beds studied. After vagotomy, coronary occlusion caused a constrictor response similar in magnitude to that caused by hemorrhage in each vascular bed and the dilator responses to occlusion at constant aortic pressure were abolished. Both constrictor and dilator changes were prevented by alpha-adrenergic blockade. Mechanical distension of the left ventricle in four dogs with carotid sinus nerves cut caused a significant reflexdilatation in the hindlimb. Thus, coronary occlusion initiates an inhibitory reflex mediated by vagal afferents which opposes peripheral vasoconstriction most effectively in the renal and paw circulations.

How does leukemia invade the central nervous system?

Prolongation of survival of children with acute leukemia by systemic therapy has brought a marded increase in incidence of CNS leukemia. In mice inoculated with leukemia cells, CNS i nfiltrates are rare unless life is prolonged by chemotherapy. Available evidence seems to indicate that leukemic cells in the CNS in most cases originate in bone marrow or lymph nodes.