Glial ion transport and volume control.

K(+)-induced glial swelling results from an intricate interaction of transport and diffusion processes and metabolic stimulation, with many open questions remaining. Our concept of the major mechanisms involved can be summarized as follows: high extracellular K+ causes a burst-like stimulation of Na+/K+ ATPase and, hence, increases the metabolic demands. Lactate is produced; the cell is slightly acidified. To maintain a normal intracellular pH, the Na+/K+ antiporter extrudes protons and supplies Na+ for further Na+/K+ exchange. In addition, K+ ions enter the cell via membrane channels or furosemide-inhibitable transport. K+, Cl-, and lactate- ions accumulate as the osmotic basis for cell swelling. Later, cell volume normalizes slowly, a process involving lactate export and other, so far unidentified mechanisms. Taken together, the temporary swelling of glia at high K+ concentrations is the result of a homeostatic function, for the maintenance of a constant extracellular potassium concentration. Ion control ranges over volume control. In pathophysiologic states the loss of cell volume regulation may become a clinical problem, if cerebral swelling leads to an increase in intracranial pressure. It should be kept in mind, however, that elevation of the extracellular K+ concentration is not the only cause of glial swelling. Tissue acidosis, the release of neurotransmitters, especially glutamate, or free fatty acids are other mediator mechanisms initiating the swelling of glial elements. Only under controlled in vitro conditions can the individual significance of these factors be evaluated on a quantitative basis. Therapeutic approaches should be selected very carefully in order to maintain homeostatic mechanisms that are of utmost importance, especially after an insult to the brain.

Late diagnosis dislocation of the hip joint in children.

Dating from 1953, the hips of newborn have been examined routinely all over Sweden. In 1963 more than 99 per cent of all newborns (about 110,000) were delivered at maternity departments, where such examination was recommended. 615 cases of preluxation or dislocation were diagnosed, which means a frequency of 5.6 per thousand. A high frequency reported in some hospitals suggests overdiagnosis. To assess to what extent the examination of newborns has reduced the frequency of late diagnosis dislocation and dysplasia, extracts of the records were obtained concerning all infants born in 1963 and treated for dislocation of the hip in 1963-1966 at orthopaedic departments in Sweden. Twenty-seven reported cases were analysed and the children were reviewed after 4-10 years. Fourteen (52 per cent) of the children were found to have normal or practically normal hips at the review. Eight still had dysplasia with subluxation and 3 had substantially deformed joints, one had moderate deformity and one, untreated, still had luxation. Possible causes of late diagnosis are discussed and it is stressed -- that all physicians who examine newborns should be well versed in examination of the hip joints.--that the hip joints should, when possible, be examined on two occasions during the first weeks of life, especially newborns predisposed to dislocation owing to heredity, breech presentation or different kinds of malformations.--that it should be borne in mind that complete luxation, though rare, may exist already in the neonatal period,--that one should not forget to examine the hips of newborns who, because of prematurity, asphyxia etc., are referred immediately for intense treatment before routine examination of the hips has been carried out,--that a child health centes one should not rely on the results of the examination during the neonatal period, but should always examine the hip joints.