RESUMEN
We used 31P spectroscopy to determine whether administration of a neutralizing dose of bicarbonate in rabbits with lactic acidosis caused a paradoxical brain intracellular acidosis. Ten 10- to 16-day-old rabbits were anesthetized with 0.75% halothane/oxygen and their lungs mechanically ventilated. Metabolic acidosis was induced by decreasing PaO2 to 25 to 35 mm Hg for 1 to 2 hours until the base deficit was 10 to 15 mEq/L. Cerebral ischemia was prevented by maintaining arterial blood pressure at +/- 20% of control value with a venous infusion of epinephrine. Hypoxia was then terminated by administration of 100% oxygen, which was continued for the remainder of the study. After 15 minutes 100% oxygen, 5 mEq/kg 4.2% bicarbonate was administered to five animals; 5 minutes later the same dose was repeated. Control rabbits were given equal volumes of saline solution. In all animals, arterial pH decreased from 7.43 +/- 0.06 to 7.25 +/- 0.08 (SE) during hypoxia, and brain intracellular pH from 7.22 +/- 0.06 to 7.09 +/- 0.09 (SE). Both pH values remained low during reoxygenation. Bicarbonate administration normalized arterial pH (7.41 +/- 0.03), whereas treatment with saline solution did not (7.23 +/- 0.01, P less than 0.05). PaCO2 rapidly increased by 10 mm Hg in the bicarbonate group, and remained elevated; it was unaffected by saline solution administration. Brain intracellular pH in the bicarbonate group increased by 0.12 U over 40 minutes, but intracellular pH in the saline solution group decreased 0.05 pH U (P less than 0.05) over the same period. We conclude that administering a total dose of 10 mEq/kg sodium bicarbonate to neonatal rabbits recovering from hypoxic lactic acidosis increases arterial pH, brain intracellular pH, and PaCO2; it does not produce paradoxical intracellular acidosis in the brain.
Asunto(s)
Acidosis Láctica/tratamiento farmacológico , Bicarbonatos/efectos adversos , Encéfalo/efectos de los fármacos , Concentración de Iones de Hidrógeno , Hipoxia/complicaciones , Sodio/efectos adversos , Acidosis Láctica/sangre , Acidosis Láctica/etiología , Animales , Bicarbonatos/uso terapéutico , Encéfalo/patología , Dióxido de Carbono , Espectroscopía de Resonancia Magnética , Presión Parcial , Conejos , Sodio/uso terapéutico , Bicarbonato de SodioRESUMEN
Differences in the occurrence of three common types of cancer among Hispanic compared to Anglo women are presented. These are cancers of the breast, colon, and lung, which together account for about half of all newly diagnosed cancers in the U.S. Differences occur in at least three different geographic areas, Texas, New Mexico, and Los Angeles. These cancer differences are presented in the light of some social and economic differences between Hispanic and Anglo women. Among them are several indicators of social class or economic development, fertility patterns, urban-rural differences, migration status and dietary habits resulting in different nutritional status between the two groups. Although a dietary hypothesis is attractive to explain the differences in breast and colon cancers, it is by no means proved. The magnitude of the differences in these cancers, coupled with their frequency of occurrence in the population, make them important sources for future study. The differences strongly suggest the existence of protective factors associated with ethnic-related life styles of Hispanic women.