Autosomal-dominante polyzystische Nierenerkrankung

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic renal disease, and it is even one of the most common hereditary diseases in man. In 85% of the cases the disease is caused by mutations in the PKD1 gene, which encodes for the ciliary protein polycystin-1. A milder variant of the disease is caused by mutations in the PKD2 gene, which encodes for the calcium channel-related protein polycystin-2. The disease is characterized by the progressive development of innumerable cysts in both kidneys, which gradually replace the normal kidney tissue. In ADPKD patients the inexorable cyst growth leads to a progressive deterioration of renal function over decades, which ultimately can only be treated by renal replacement therapy or renal transplantation. Until now a causal treatment was not available, and treatment options were limited to regular clinical controls and treatment of complications (hypertension, cyst infections). Several promising clinical studies are currently examining new or even existing drugs as therapeutic options to retard cyst growth in ADPKD (vasopressin receptor-2 antagonists [V2RA], mammalian target of rapamycin [mTOR] inhibitors, somatostatin). It can be anticipated that ADPKD patients will benefit from these new treatment options in the near future.     

Puesta al día en el reflujo gastroesofágico

Gastroesophageal reflux disease is a highly frequent disorder classically characterized by the presence of heartburn and/or acid regurgitation that improves with drug therapy that reduces acid content in the stomach. However, especially in patients with non-erosive disease, response to proton pump inhibitors is unsatisfactory in approximately 1 out of 3 patients, and consequently, in these patients, it is important to establish a definitive diagnosis and an alternative therapeutic strategy. In the last few years, advances have been made in knowledge of the physiopathology of reflux, such as identification of the role of the acid pocket in producing reflux, technological advances that allow differentiation among acid reflux, non-acid reflux and slightly acid reflux, and advances in the treatment of reflux with drugs that attempt to act on the barrier function of the esophagogastric junction.     

Axon reflexes or ephaptic responses simulating blink reflex R1 after XII-VII nerve anastomosis

It has been claimed that functional recovery of the blink reflex occurs after hypoglossal-facial nerve anastomosis. This has been explained through central nervous system plasticity and reorganization of neuronal connections. In 5 patients with reinnervated facial muscles after hypoglossal-facial nerve anastomosis, we observed “R1-like” responses that fulfilled criteria for facial nerve axon reflexes or ephapses. First, displacement of the stimulating electrode from the supraorbital to the zygomatic area shortened the latency of the evoked response. Second, these responses were stable (jitter mean consecutive difference < 25 μs) and they had complex potential shapes unmodified by high-frequency stimulation. Finally, collision techniques demonstrated antidromic conduction of impulses in the facial nerve from supraorbital to zygomatic points. Therefore, these “R1-like” responses are not the early component of a functionally recovered blink reflex but motor axon reflexes or ephaptic responses similar to the short latency responses observed following facial nerve regeneration or from sutured nerves in human forearms. © 1996 John Wiley & Sons, Inc.     

Heat shock increases antigenic peptide generation but decreases antigen presentation

The heat shock response is a universal and highly conserved cellular response to stress. We describe here the effect of elevated temperature on the capacity of B cells to present antigen. Heat shock markedly affects the ability of these cells to process and present tetanus toxin to class II-restricted T cell clones. Inhibition of antigen presentation is due neither to a modification of antigen capture nor to a variation of major histocompatibility complex (MHC) class II molecule synthesis and cell surface expression. Stressed and nonstressed B cells are able to present peptides loaded at the cell surface with the same efficiency. Nevertheless, heat shock leads to an increase of antigen peptide generation in subcellular compartments; an enhancement of cathepsin B activity is also observed. These data suggest that such a stress induces a failure in the intracellular peptide loading onto MHC class II molecules.     

Thermosets obtained by chemical modification of poly(epichlorohydrin) with vinyl-terminated aromatic carboxylates

Poly(epichlorohydrin) was modified in a high extent with several vinyl-terminated aromatic potassium carboxylates (4-(2-propenyloxy)benzoate, 4-(5-hexenyloxy)benzoate, 3-(2-propenyloxy)-2-naphthoate, 3-(5-hexenyloxy)-2-naphthoate and 2-(thioallyl)nicotinate) under solid-liquid phase-transfer conditions. Simultaneously with this substitution reaction, cleavage and crosslinking side reactions occurred. The polymers obtained were characterized by NMR, IR, elemental analysis, viscosimetry, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Then, crosslinked materials were obtained by curing mixtures of these linear polymers with 10% w/w of a radical initiator (dicumyl peroxide or 2,2′-azoisobutyronitrile) on a DSC device. Finally, the thermal stability of the thermosetting materials was tested by TGA, and the Arrhenius kinetic parameters were determined for dicumyl peroxide initiated crosslinking processes by calorimetric measurements.