Parkinson's disease.

In Parkinson''s disease there is degeneration of neurons in the substantia nigra, with consequent depletion of the neurotransmitter dopamine. The triad of tremor, rigidity and bradykinesia is the clinical hallmark. Drugs currently used for palliative therapy fall into three categories: anticholinergic agents, dopamine precursors (levodopa combined with extracerebral decarboxylase inhibitors) and artificial dopamine agonists. It has been argued, on theoretical grounds, that some drugs slow the progress of Parkinson''s disease, although no firm evidence has supported this. Treatment must be individualized, and more than one type of drug can be given concurrently after a careful build-up in dosage. We review the adverse effects of various drugs and consider new developments such as slow-release preparations, selective D-1 and D-2 agonists and transplants of dopaminergic cells into the brain. The treatment of Parkinson''s disease can be demanding, rewarding and sometimes frustrating, but it remains a most challenging exercise in pharmacotherapy.     

Tc-99m-Labeling of Modified RNA

Abstract

The synthesis of Tc-99m-labeled, modified RNA is reported. This new class of radiopharmaceuticals is of potential interest as target specific imaging agents. The preparation of N₃S-RNA was achieved by coupling protected MAG₂-units to amino modified ON's. The N₃S-RNA was Tc-99m-labeled with 90–95% radiochemical yield and specific activities of 37MBq/nmol leading to 1:1-Tc-99m-N₃S-aptamers.     

Kurze Mitteilungen

Ohne Zusammenfassung     

The troublesome parasites--molecular and morphological evidence that Apicomplexa belong to the dinoflagellate-ciliate clade.

Large insertions and deletions in the variable regions of eukaryotic 16S-like rRNA relative to the archaebacterial structure have been defined as a marker for rapidly evolving taxa. Deletions in the rRNA occur in the diplomonad Giardia and the microsporidian Vairimorpha, whereas insertions occur in Euglenozoa (Euglena and the kinetoplastids), Acanthamoeba, Naegleria, Physarum, Dictyostelium, the apicomplexan Plasmodium, the ciliate Euplotes, and some metazoa. Except Acanthamoeba and Euplotes, all of these protists were previously placed at the base of the eukaryote phylogeny. A re-analysis of the 16S-like rRNA and 5S rRNA data with the neighborliness method revealed a close relationship of Apicomplexa to the dinoflagellate-ciliate clade, most probably closer to the dinoflagellates. Morphological evidence that supports this grouping is the layer of sacs underneath the plasma membrane in all three taxa and the identical structure of trichocysts in the apicomplexan Spiromonas and dinoflagellates. The remaining rapidly evolving organisms might still be misplaced in the 16S-like rRNA trees.