ABSTRACT
It is well established that the targeted receptor for ciguatoxin (CTX) in mammalian tissues is the sodium channel, affecting the influx of sodium into cells and altering the action potential and function of the cell. Since the syntheses of fragments of CTX has become available, our focus has been on the receptor functions of the west sphere AB and east sphere JKLM fragments using the neuroblastoma cell assay, guinea pig atrium assay, and the membrane immunobead assay (MIA). The data presented here suggest that the west sphere AB of the ciguatoxin molecule is the active portion and is responsible for the activation of the sodium channels.
Subject(s)
Ciguatoxins/pharmacology , Neurons/drug effects , Sodium Channels/drug effects , Animals , Cell Line, Tumor , Ciguatoxins/antagonists & inhibitors , Ciguatoxins/chemistry , Epitopes , Guinea Pigs , Heart Atria/drug effects , Heart Atria/physiopathology , Male , Mice , Myocardial Contraction/drug effects , Myocardial Contraction/physiology , Neuroblastoma/metabolism , Neuroblastoma/pathology , Neurons/metabolism , Neurons/pathology , Seafood/analysis , Sodium Channels/metabolism , Structure-Activity Relationship , SwineABSTRACT
A case of unilateral vesicoureteric junction obstruction presenting with ascites in a neonate managed successfully with serial ultrasonography and delayed primary reconstruction is described.
Subject(s)
Ascites/etiology , Ureteral Obstruction/complications , Urinary Bladder Diseases/complications , Urologic Diseases/etiology , Ascites/therapy , Humans , Infant, Newborn , Male , Ureteral Obstruction/therapy , Urinary Bladder Diseases/therapy , Urologic Diseases/therapyABSTRACT
Age-related changes in the hepatic microcirculation may contribute to the increased susceptibility of the immature liver to microvascular injury. We quantified sinusoidal and acinar diameters, sinusoidal red cell velocities (VRBC), and sinusoidal volume flows to characterize microhemodynamics of weanling and adult rat livers with and without hepatic artery (HA) ligation using intravital fluorescence videomicroscopy. Despite a 20% faster heart rate and a nearly 20% lower mean arterial and portal vein pressure in weanling rats relative to those in the adults, weanling periportal and pericentral sinusoidal velocities were approximately 30 and 25% faster, respectively, than those in adults. Furthermore, the HA was found to contribute more to maintenance of sinusoidal VRBC in the immature liver as demonstrated by a significant decrease in both periportal and pericentral VRBC following HA ligation. HA ligation had no effect on VRBC of either zone in adults. Zonal volume flow (HA intact), however, was maintained independent of age. These results suggest a lower extrasinusoidal resistance in the weanling. The 25% shorter acinar diameter that we found in weanling livers likely contributes to a lower extrasinusoidal resistance by allowing a higher ratio of inflow vessels to volume of tissue. Shorter sinusoidal pathways in weanling livers also decreases sinusoidal resistance 1.3-fold relative to that in the adult, countering the approximately 1.5 times increase in resistance due to the smaller caliber of sinusoidal vessels so that overall sinusoidal resistance is not age-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)
