This paper discusses and illustrates various approaches for the longitudinal analysis of personal networks (multilevel analysis, regression analysis, and SIENA). We combined the different types of analyses in a study of the changing personal networks of immigrants. Data were obtained from 25 Argentineans in Spain, who were interviewed twice in a two-year interval. Qualitative interviews were used to estimate the amount of measurement error and to isolate important predictors. Quantitative analyses showed that the persistence of ties was explained by tie strength, network density, and alters' country of origin and residence. Furthermore, transitivity appeared to be an important tendency, both for acquiring new contacts and for the relationships among alters. At the network level, immigrants' networks were remarkably stable in composition and structure despite the high turnover. Clustered graphs have been used to illustrate the results. The results are discussed in light of adaptation to the host society.

We report two cases of ascending muscular weakness progressing to areflexic quadriplegia caused by severe derangement of potassium homeostasis. The first patient presented with a 17-alpha-hydroxylase deficiency and severe hypokalemia. The second case had primary adrenocortical deficiency (Addison's disease) and extreme hyperkalemia. Complete recovery ensued after correction of the metabolic disorder in both cases. The role of potassium in the pathophysiology of neuromuscular excitation is discussed. We conclude that when neuromyopathy is present, metabolic causes should be considered and the serum potassium determined.

Liver and lung metallothionein (MT) levels were increased by endotoxin. The administration of superoxide dismutase (SOD) or allopurinol (ALLO) before (30-60 min) or after (24-32 h) the endotoxin treatment either increased or did not affect the effect of endotoxin on MT levels, depending on the particular treatment and tissue. SOD and ALLO also increased liver and lung MT levels in control rats. In contrast, liver MT levels tended to be decreased by the glucocorticoid prednisolone (PRED) when administered before the endotoxin and were significantly decreased when it was administered after endotoxin. The effect of PRED on lung MT levels was completely different, since it decreased the effect of endotoxin when injected before the lipopolysaccharide, but increased it when injected after the endotoxin. Liver lipid peroxidation, as measured by thiobarbituric acid reactants (TBARs), increased after endotoxin in the liver but not in the lung, an effect even potentiated in some cases by the antioxidants studied. As expected, tissue MT and TBARs could not be correlated.