Plasma Membrane and Chromaffin Granule Characteristics in Digitonin-Treated Chromaffin Cells

Digitonin permeabilizes the plasma membranes of bovine chromaffin cells to Ca 2+ , ATP, and proteins and allows micromolar Ca 2+ in the medium to stimulate directly catecholamine secretion. In the present study the effects of digitonin (20 Μ M ) on the plasma membrane and on intracellular chromaffin granules were further characterized. Cells with surface membrane labeled with [ 3 H]galactosyl moieties retained label during incubation with digitonin. The inability of digitonin-treated cells to shrink in hyperosmotic solutions of various compositions indicated that tetrasaccharides and smaller molecules freely entered the cells. ATP stimulated [ 3 H]norepinephrine uptake into digitonin-treated chromaffin cells fivefold. The stimulated [ 3 H]norepinephrine uptake was inhibited by 1 Μ M reserpine, 30 m M NH 4 + , or 1 Μ M carbonyl cyanide p -trifluoromethoxyphenylhydrazone (FCCP). The data indicate that [ 3 H]norepinephrine was taken up into the intracellular storage granules by the ATP-induced H + electrochemical gradient across the granule membrane. Reduction of the medium osmolality from 310 mOs to 100 mOs was required to release approximately 50% of the catecholamine from chromaffin granules within digitonin-treated chromaffin cells which indicates a similar osmotic stability to that in intact cells. Chromaffin granules in vitro lost catecholamine when the digitonin concentration was 3 Μ M or greater. Catecholamine released into the medium by micromolar Ca 2+ from digitonin-treated chromaffin cells that had subsequently been washed free of digitonin could not be pelleted in the centrifuge and was not accompanied by release of membrane-bound dopamine-Β-hydroxylase. The studies demonstrate that 20 Μ M of digitonin caused profound changes in the chromaffin cell plasma membrane permeability but had little effect on intracellular chromaffin granule stability and function. It is likely that the intracellular chromaffin granules were not directly exposed to significant concentrations of digitonin. Furthermore, the data indicate that during catecholamine release induced by micromolar Ca 2+ , the granule membrane was retained by the cells and that catecholamine release did not result from release of intact granules into the extracellular medium.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65144/1/j.1471-4159.1985.tb07226.x.pd

Effects of Osmolality and Ionic Strength on Secretion from Adrenal Chromaffin Cells Permeabilized with Digitonin

Hyperosmotic solutions inhibit exocytosis of catecholamine from adrenal chromaffin cells at a step after Ca 2+ entry into the cells. The possibility that the inhibition resulted from an inability of shrunken secretory granules to undergo exocytosis was investigated in cells with plasma membranes permeabilized by digitonin. The osmoticants and salts used in this study rapidly equilibrated across the plasma membrane and bathed the intracellular organelles. When sucrose was the osmoticant, secretion was not significantly inhibited unless the osmolality was raised above 1,000 mOs. When the osmolality was raised with the tetrasaccharide stachyose or a low-molecular-weight maltodextrin fraction (average size a tetrasaccharide), one-half maximal inhibition occurred at 900–1,000 mOs. Prior treatment of permeabilized cells with Ca 2+ in hyperosmotic solution did not result in enhanced secretion when cells were restored to normal osmolality. Increased concentrations of potassium glutamate or sodium isethionate were more potent than carbohydrate in inhibiting secretion. Half-maximal inhibition occurred at 600–700 mOs or when the ionic strength was approximately doubled. The inhibition by elevated potasium glutamate also occurred when the osmolality was kept constant with sucrose. Increasing the ionic strength did not alter the Ca 2+ sensitivity of the secretory response. Reducing the ionic strength by substituting sucrose for salt reduced the Ca 2+ concentration required for half-maximal stimulated secretion from approximately 1.2 Μ M . Chromaffin granules, the secretory granules, are known to shrink in hyperosmotic solution. The experiments indicate that shrunken chromaffin granules can undergo exocytosis and suggest that in intact cells elevated ionic strength rather than chromaffin granule shrinkage contributes to the inhibition of secretion by hyperosmotic solutions. The experiments place limits on the possible osmotic mechanisms that could be involved in exocytosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66041/1/j.1471-4159.1986.tb08502.x.pd

Relationship Between Ca 2+ Uptake and Catecholamine Secretion in Primary Dissociated Cultures of Adrenal Medulla

Carbachol or elevated K + stimulated 45 Ca 2+ uptake into chromaffin cells two- to fourfold. The uptake was stimulated by cholinergic drugs with nicotinic activity, but not by those with only muscarinic activity. Ca 2+ uptake and catecholamine secretion induced by the mixed nicotinic-muscarinic agonist carbachol were inhibited by the nicotinic antagonist mecamylamine, but not by the muscarinic antagonist atropine. Significant Ca 2+ uptake occurred within 15 s of stimulation by carbachol or elevated K + at a time before catecholamine secretion was readily detected. At later times the time course of secretion induced by carbachol or elevated K + was similar to that of Ca 2+ uptake. There was a close correlation between Ca 2+ uptake and catecholamine secretion at various concentrations of Ca 2+ . The concentration dependencies for inhibition of both processes by Mg 2+ or Cd 2+ were similar. Ca 2+ uptake saturated with increasing Ca 2+ concentrations, with an apparent K m for both carbachol-induced and elevated K + -induced Ca 2+ uptake of approximately 2 m M . The Ca 2+ dependency, however, was different for the two stimuli. The studies provide strong support for the notion that Ca 2+ entry and a presumed increase in cytosolic Ca 2+ concentration respectively initiates and maintains secretion. They also provide evidence for the existence of saturable, intracellular, Ca 2+ - dependent processes associated with catecholamine secretion. Ca 2+ entry may, in addition, enhance nicotinic receptor desensitization and may cause inactivation of voltage-sensitive Ca 2+ channels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66166/1/j.1471-4159.1982.tb07940.x.pd

A New Troodontid Theropod Dinosaur from the Lower Cretaceous of Utah

BACKGROUND: The theropod dinosaur family Troodontidae is known from the Upper Jurassic, Lower Cretaceous, and Upper Cretaceous of Asia and from the Upper Jurassic and Upper Cretaceous of North America. Before now no undisputed troodontids from North America have been reported from the Early Cretaceous. METHODOLOGY/PRINCIPAL FINDINGS: Herein we describe a theropod maxilla from the Lower Cretaceous Cedar Mountain Formation of Utah and perform a phylogenetic analysis to determine its phylogenetic position. The specimen is distinctive enough to assign to a new genus and species, Geminiraptor suarezarum. Phylogenetic analysis places G. suarezarum within Troodontidae in an unresolved polytomy with Mei, Byronosaurus, Sinornithoides, Sinusonasus, and Troodon+(Saurornithoides+Zanabazar). Geminiraptor suarezarum uniquely exhibits extreme pneumatic inflation of the maxilla internal to the antorbital fossa such that the anterior maxilla has a triangular cross-section. Unlike troodontids more closely related to Troodon, G. suarezarum exhibits bony septa between the dental alveoli and a promaxillary foramen that is visible in lateral view. CONCLUSIONS/SIGNIFICANCE: This is the first report of a North American troodontid from the Lower Cretaceous. It therefore contributes to a fuller understanding of troodontid biogeography through time. It also adds to the known dinosaurian fauna of the Cedar Mountain Formation

Tierra Grande: Journal of the Real Estate Center at Texas A&M University

Quarterly journal providing information related to various aspects of real estate buying and ownership

Tierra Grande: Journal of the Real Estate Center at Texas A&M University

Quarterly journal providing information related to various aspects of real estate buying and ownership

Emotional processes and stress in children affected by hereditary angioedema with C1-inhibitor deficiency : a multicenter, prospective study

Background: Hereditary angioedema with C1-inhibitor deficiency (C1-INH-HAE) is characterized by recurrent edema of unpredictable frequency and severity. Stress, anxiety, and low mood are among the triggering factors most frequently reported. Impaired regulation and processing of emotions, also known as alexithymia, may influence outcomes. The aim of this study was to confirm the presence of alexithymia and stress in children with C1-INH-HAE, to determine whether they are also present in children affected by other chronic diseases, and to investigate their relationship with C1-INH-HAE severity. Data from children with C1-INH-HAE (n = 28) from four reference centers in Italy were compared with data from children with type 1 diabetes (T1D; n = 23) and rheumatoid arthritis (RA; n = 25). Alexithymia was assessed using the Alexithymia Questionnaire for Children scale; perceived stress was assessed using the Coddington Life Event Scale for Children (CLES-C). Results: Mean age (standard deviation [SD]) in the C1-INH-HAE, T1D, and RA groups was 11.8 (3.3), 11.7 (2.9), and 11.1 (2.6) years, respectively. Mean C1-INH-HAE severity score was 5.9 (2.1), indicating moderate disease. Alexithymia scores were similar among disease groups and suggestive of difficulties in identifying and describing emotions; CLES-C scores tended to be worse in C1-INH-HAE children. C1-INH-HAE severity was found to correlate significantly and positively with alexithymia (p = 0.046), but not with perceived stress. Alexithymia correlated positively with perceived stress. Conclusions: Alexithymia is common in children with chronic diseases. In C1-INH-HAE, it may result in increased perceived stress and act as a trigger of edema attacks. Comprehensive management of C1-INH-HAE children should consider psychological factors

Tierra Grande: Journal of the Real Estate Center at Texas A&M University

Quarterly journal providing information related to various aspects of real estate buying and ownership

ELABORAÇÃO DE BISCOITO TIPO COOKIE SEM GLÚTEN, À BASE DE MILHO, ARROZ E MANDIOCA

O objetivo deste projeto está relacionado com o desenvolvimento de um biscoito nutritivo do tipo cookie a partir de ingredientes como milho, arroz, polvilho de mandioca e grãos, isentos de glúten, substância intolerável para celíacos. O desenvolvimento deste projeto visa a utilização de matérias-primas cultivadas em Santa Catarina de forma a agregar valor e diversificar as opções de aplicação e emprego das mesmas, buscando a inovação com o desenvolvimento de produtos diferenciados e que atendam a consumidores cada vez mais exigentes

Antigenic Characterization of H3 Subtypes of Avian Influenza A Viruses from North America

Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable. Además de infectar a los seres humanos, los subtipos H3 del virus de la influenza A (IAVs) pueden infectar a varios huéspedes animales, incluyendo aves, porcinos, equinos, caninos, y especies de mamíferos marinos. Estos virus H3 son tanto antigénica y genéticamente diversos. En este estudio, se caracterizó la diversidad antigénica de virus H3 contemporáneos recuperados de aves migratorias en América del Norte. Se realizaron pruebas de inhibición de la hemaglutinación (HI) en 37 H3 aislamientos de origen aviar recuperados de 2007 a 2011 usando sueros de pollo de referencia. Estos aislamientos fueron recuperados de las muestras tomadas de las rutas migratorias de aves acuáticas del Atlántico, Mississippi, Centro y del Pacífico. Los antisueros de todos los aislamientos H3 analizados mostraron reacciones cruzadas entre sí y en menor medida, con aquellos virus H3 de origen canino y equino. La cartografía antigénica demostró que la mayor distancia antigénica entre los 37 virus de este tipo de aves es de aproximadamente cuatro unidades, y cada unidad corresponde a una diferencia de dos logaritmos en el título de inhibición de la hemaglutinación. Sin embargo, ninguno de los virus H3 de este tipo mostró reacción cruzada con sueros de hurón específicos para virus de cerdos y humanos contemporáneos. Estos resultados mostraron que los virus H3 de origen aviar que se analizaron carecían de diversidad antigénica significativa y estos virus fueron antigénicamente diferentes de las que circulan en poblaciones de cerdos y de humanos. Esto sugiere que los virus H3 de aves acuáticas de América del Norte son relativamente estables antigénicamente