Identification of a lectin causing the degeneration of neuronal processes using engineered embryonic stem cells

Unlike the mechanisms involved in the death of neuronal cell bodies, those causing the elimination of processes are not well understood owing to the lack of suitable experimental systems. As the neurotrophin receptor p75(NTR) is known to restrict the growth of neuronal processes, we engineered mouse embryonic stem (ES) cells to express an Ngfr (p75(NTR)) cDNA under the control of the Mapt locus (the gene encoding tau), which begins to be active when ES cell-derived progenitors start elongating processes. This caused a progressive, synchronous degeneration of all processes, and a prospective proteomic analysis showed increased levels of the sugar-binding protein galectin-1 in the p75(NTR)-engineered cells. Function-blocking galectin-1 antibodies prevented the degeneration of processes, and recombinant galectin-1 caused the processes of wild-type neurons to degenerate first, followed by the cell bodies. In vivo, the application of a glutamate receptor agonist, a maneuver known to upregulate p75(NTR), led to an increase in the amount of galectin-1 and to the degeneration of neurons and their processes in a galectin-1-dependent fashion. Section of the sciatic nerve also rapidly upregulated levels of p75(NTR) and galectin-1 in terminal Schwann cells, and the elimination of nerve endings was delayed at the neuromuscular junction of mice lacking Lgals1 (the gene encoding galectin-1). These results indicate that galectin-1 actively participates in the elimination of neuronal processes after lesion, and that engineered ES cells are a useful tool for studying relevant aspects of neuronal degeneration that have been hitherto difficult to analyze.     

A Case of Onychomycosis caused by Curvularia lunata (Wakker) Boedijn/ Ein Fall einer Onychomykose durch Curvularia lunata (Wakker) Boedijn

Summary: A case of onychomycosis involving all the finger and toe nails caused by Curvularia lunata is described in a patient with a primary debilitating disease. The presence of dematiaceous hyphae, germinating conidia within the nail tissue, and the repeated isolation of the fungus in culture from the diseased nail along with the absence of any established pathogenic species are taken as evidence that this fungus was actually invading the nail tissue.
Zusammenfassung: Bericht über eine Onychomykose aller Finger- und Zehennägel bei einem Leprapatienten, der außerdem unter immunsuppressiver Therapie stand. Der Nachweis für die Erregernatur dieses Pilzes gründet sich auf die Anwesenheit von pigmentierten Hyphen im Nativpräparat, auf die Beobachtung auskeimender Konidien in der Nagelsubstanz und auf den wiederholten kulturellen Nachweis des Pilzes aus den erkrankten Nägeln, wobei keine anderen pathogenen Pilze zusätzlich gefunden wurden.