The developmental regulation and biosynthesis of GPI-related structures in Leishmania parasites

Most macromolecules on the surface of Leishmania parasites, including the major surface proteins and a complex lipophosphoglycan (LPG) are anchored to the plasma membrane via GPI glycolipids. Free glycoinositol-phospholipids (GIPLs) which are not linked to protein or phosphoglycan are also abundant in the plasma membrane. From structural and metabolic labeling studies it is proposed that most Leishmania species express three distinct pathways of GPI biosynthesis. Some of these pathways (i.e those involved in the protein and LPG anchor biosynthesis) are down-regulated during the differentiation of the insect (promastigote) stage to the mammalian (amastigote) stage. In contrast, the GIPLs are expressed in high copy number in both developmental stages. Based on analysis of the lipid moieties of the different GPI species it is possible that the pathways of GPI anchor and GIPL biosynthesis are located in different subcellular compartments. The relative flux through the GIPL and LPG biosynthetic pathways has been examined in L. Major promastigotes. These studies showed that while the rate of synthesis of the GIPLs and LPG is similar, LPG is shed more rapidly from the plasma membrane and has a higher turnover. The possible metabolic relationship between the GIPL and LPG biosynthetic pathways is discussed

Escleroterapia endoscópica de varices esof gicas sangrantes: resultados obtenidos en 31 casos tratados y su evolución durante 28-33 meses post-escleroterapia / Follow up the 31 cases after endoscopic sclerotherapy of the bleeding esophagic varicose veins

Entre 1986 a 1989 hemos esclerosado v rices sangrantes en 31 pacientes adultos (18 casos asistenciales y 13 casos privados); 28 (90/100) presentaban hepatopatía alcohólica crónica, 2 (6.3/100) cirrosis criptogénica y 1 (3.2/100)trombosis portal ideop tica. Quince pacientes fueron admitidos con sangrado agudo; a 7 se les esclerosó sangrando activamente (etapa aguda) y a los 8 restantes después de estabilizarlos hemodin micamente y controlada la hemorragia con la colocación de sonda de balones (etapa temprana). Los otros 16 pacientes fueron esclerosados electivamente semanas a meses después de haber presentado su último sangrado. No hubo ningún caso de mortalidad directamente relacionada con el procedimiento; la frecuencia y severidad de las complicaciones asociadas al procedimiento fueron moderadas y semejantes a lo reportado por otros autores en la literatura. En el grupo agudo se logró controlar la hemorragia después de la primera sesión de escleroterapia; sin embargo 4 de estos pacientes fallecieron entre uno y seis días después de la escleroterapia debido a insuficiencia hep tica irreversible sin que volvieran a sangrar...