Rapid percutaneous nephrostomy catheter placement in neonates with the trocar technique.

PURPOSE: The purpose of this study was to assess the efficacy of a modified percutaneous nephrostomy procedure for grade III-IV hydronephrosis in neonates. MATERIAL AND METHODS: Eleven neonates (five girls, six boys) with a mean age of 13.7days±9.9 (SD) (range, 4-28days) with pronounced hydronephrosis had percutaneous nephrostomy using a modified procedure. In all patients, percutaneous nephrostomy was performed with a trocar catheter under ultrasound guidance and then the catheter was placed into the collecting system without prior dilatation. RESULTS: Technical success was achieved in all patients. There were no major procedure-related complications. There was no perirenal hematoma on control ultrasound examinations and no hematuria was observed after the procedure. The median drainage time was 75days (range: 42-120days). Two children had urinary tract infection, which was controlled by using antibiotics. CONCLUSION: The trocar nephrostomy is a practical and feasible method, which can be used for neonates with grade III-IV hydronephrosis.

The initiator caspase Dronc is subject of enhanced autophagy upon proteasome impairment in Drosophila.

A major function of ubiquitylation is to deliver target proteins to the proteasome for degradation. In the apoptotic pathway in Drosophila, the inhibitor of apoptosis protein 1 (Diap1) regulates the activity of the initiator caspase Dronc (death regulator Nedd2-like caspase; caspase-9 ortholog) by ubiquitylation, supposedly targeting Dronc for degradation by the proteasome. Using a genetic approach, we show that Dronc protein fails to accumulate in epithelial cells with impaired proteasome function suggesting that it is not degraded by the proteasome, contrary to the expectation. Similarly, decreased autophagy, an alternative catabolic pathway, does not result in increased Dronc protein levels. However, combined impairment of the proteasome and autophagy triggers accumulation of Dronc protein levels suggesting that autophagy compensates for the loss of the proteasome with respect to Dronc turnover. Consistently, we show that loss of the proteasome enhances endogenous autophagy in epithelial cells. We propose that enhanced autophagy degrades Dronc if proteasome function is impaired.

Genetic characterization of two gain-of-function alleles of the effector caspase DrICE in Drosophila.

Caspases are the executioners of apoptosis. Although much is known about their physiological roles and structures, detailed analyses of missense mutations of caspases are lacking. As mutations within caspases are identified in various human diseases, the study of caspase mutants will help to elucidate how caspases interact with other components of the apoptosis pathway and how they may contribute to disease. DrICE is the major effector caspase in Drosophila required for developmental and stress-induced cell death. Here, we report the isolation and characterization of six de novo drICE mutants, all of which carry point mutations affecting amino acids conserved among caspases in various species. These six mutants behave as recessive loss-of-function mutants in a homozygous condition. Surprisingly, however, two of the newly isolated drICE alleles are gain-of-function mutants in a heterozygous condition, although they are loss-of-function mutants homozygously. Interestingly, they only behave as gain-of-function mutants in the presence of an apoptotic signal. These two alleles carry missense mutations affecting conserved amino acids in close proximity to the catalytic cysteine residue. This is the first time that viable gain-of-function alleles of caspases are described in any intact organism and provides a significant exception to the expectation that mutations of conserved amino acids always abolish the pro-apoptotic activity of caspases. We discuss models about how these mutations cause the gain-of-function character of these alleles.