Ultrastructural localization of RNA in the chromatoid bodies of undifferentiated cells (neoblasts) in planarians by the RNase–gold complex technique

Undifferentiated cells of planarians (Platyhelminthes, Turbellaria), also called neoblasts, are totipotent stem cells, which give rise to all differentiated cell types, while maintaining their own density by cell proliferation. Neoblasts are the only somatic cells of planarians bearing chromatoid bodies in their cytoplasm; these organelles disappear as differentiation takes place. Studies on germinal cells of several groups of organisms have shown that chromatoid bodies contain substantial amounts of RNA. To test its presence in neoblasts, we have used an RNase–gold technique. We found chromatoid bodies labeled with RNase–gold particles. Heterogeneity in the density of the label, may be correlated with the functionality and complexity of these organelles. The gold marker was also present over the nucleus and rough endoplasmic reticulum, but mitochondria, secretory granules, and the extracellular space were devoid of label. This specific localization of RNA in planarian chromatoid bodies supports earlier findings on germ cells and embryonic cells in a variety of organisms, indicating that chromatoid bodies are information-storage structures, essential during the process of cell differentiation. © 1993 Wiley-Liss, Inc.     

White matter fractional anisotropy is related to processing speed in metabolic syndrome patients: a case-control study

Background  

Metabolic Syndrome (MetSd) is a cluster of vascular risk factors that may influence cerebrovascular pathology during aging. Recently, microstructural white matter (WM) changes detected by diffusion tensor imaging (DTI) and processing speed deficits have been reported in MetSd patients. We aimed to test the relationship between WM alteration and cognitive impairment in these patients.     

Effects of Poisoning on Serum Enzyme Activities,Coagulation, and Fibrinolysis

Prolonged coma due to acute overdosage with hypnotic drugs is shown to be associated with a pronounced increase in the activity of serum creatine kinase and in the concentration of fibrin degradation products and with less pronounced abnormalities of other serum enzymes and of other indices of coagulation and fibrinolysis. Evidence is presented that skeletal muscle damage occurs and that this is related to the coagulation abnormality. These findings probably explain some of the non-specific features such as fever which commonly occur in recovery from severe poisoning.