Raphael Massarelli - Academia.edu (original) (raw)
Papers by Raphael Massarelli
Advances in biochemical psychopharmacology
Journal of Pharmacology and Experimental Therapeutics
Biochemical Society Transactions
Comptes rendus des séances de l'Académie des sciences. Série III, Sciences de la vie
Two kinetic mechanisms are responsible for the uptake of choline in Rat brain synaptosomal fracti... more Two kinetic mechanisms are responsible for the uptake of choline in Rat brain synaptosomal fractions with different affinity towards the substrate (high affinity mechanism: Km 5.1 microM, Vmax 44 pmol/mg prot/min.; low affinity mechanism: 35.7 microM, Vmax 286 pmol/mg prot/min). The treatment of synaptosomal fractions with neuraminidase (15 min. at 37 degrees C) followed by 1 min. incubation with various concentrations of [14C] choline reduces the uptake in parallel with the disappearance of the high affinity mechanism (Km 202.2 microM, Vmax 119 pmol/mg prot/min.), without influencing the synthesis of acetylcholine.
Comptes Rendus de l Académie des Sciences - Series III - Sciences de la Vie
A mixture of exogenous gangliosides at 10(-8) M and 10(-5) M concentration added to the medium of... more A mixture of exogenous gangliosides at 10(-8) M and 10(-5) M concentration added to the medium of chick neurons stimulates the metabolism of inositol compounds. Notably the incorporation of [3H] myo-inositol is increased in phosphatidylinositol and in inositol triphosphate. Gangliosides, hence, by increasing the production of second messengers might regulate the phosphorylation processes of neuronal proteins.
Birth defects original article series
ABSTRACT
Advances in Experimental Medicine and Biology
Comptes rendus des séances de l'Académie des sciences. Série III, Sciences de la vie
The existence of UDP-galactose:galactosyltransferase activities at the external surface of cultur... more The existence of UDP-galactose:galactosyltransferase activities at the external surface of cultured neurons from chick embryo hemispheres, was demonstrated. [14C]-galactose was transferred upon cellular substrates present on the neuronal surface and upon exogenous substrates (ovomucoïd) bound to Sepharose beads. The activity of ectogalactosyltransferase was not due to a leakage of intracellular enzymes into the incubation medium nor to an intracellular enzymatic activity utilizing [14C]-galactose obtained from the hydrolysis of UDP-[14C]-galactose. Kinetics of these ectogalactosyltransferases were analysed. The results support the hypothesis of a communication and/or interaction among the nerve cell surfaces via glycoconjugates or their biosynthetic enzymes.
Comptes Rendus de l Académie des Sciences - Series III - Sciences de la Vie
Several cell lines have been derived from an ocular melanoma obtained from an enucleated patient.... more Several cell lines have been derived from an ocular melanoma obtained from an enucleated patient. Three cell types are observed during the time in culture of all the cell lines under study. Two of them have epithelial and spindle shape respectively. A third cell type, having a spheroidal shape, is formed from spindle cells and may be transformed into epithelial cells upon re-seeding. Further experiments showed that the same cell may change of shape following the cycle: spheroidal-->epithelial-->fusiform-->spheroidal. Scanning microscopy shows the coexistence of the three cell shapes in the same culture and the presence of several filaments and processes protruding at the surface of the cells. Transmission electron microscopy shows that the cell lines, in general, contain melanosomes empty or fairly pigmented and several filaments and microtubules. The presence of melanin may be stimulated by seeding of melanoma cells over a "feeder layer" of fibroblasts.
Journal of lipid mediators
Several amphiphilic cations such as mepacrine, desipramine, didodecyldimethylamine, chlorpromazin... more Several amphiphilic cations such as mepacrine, desipramine, didodecyldimethylamine, chlorpromazine, oleylamine and W-7 activated the phospholipase D (PLD) activity of cultured LA-N-2 cells. These compounds, except for oleylamine, provoked the release of fatty acids, suggesting phospholipase A activation. Melittin, a PLA2 stimulator, caused the robust release of the free fatty acids but was a poor PLD activator. Although PLD could be activated by GTP gamma S, the stimulation by these amphiphilic cations was not abolished by GDP beta S, an inhibitor of G protein function. There was no change in the PLD activation by these amphiphilic cations by DiC8, a PKC activator, or by H-7, a PKC inhibitor or in PKC down-regulated cells.
Journal of lipid mediators
The stimulatory effects of sphingosine and oleylamine upon the incorporation of [3H]serine into i... more The stimulatory effects of sphingosine and oleylamine upon the incorporation of [3H]serine into its corresponding phospholipid, phosphatidylserine, by LA-N-2 cell cultures, have been reported (Singh et al. (1992) FEBS Lett., 296, 166-168). The presence of chlorpromazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) in cultures of these cells provoked increased phosphatidylserine synthesis but decreased protein synthesis in a concentration-dependent fashion. Several other amphiphilic cations, including dimethyldidodecylammonium bromide, verapamil, desipramine, amitriptyline, and mepacrine also stimulated phosphatidylserine synthesis in a dose-dependent manner. These amphiphilic cations reduced the conversion of phosphatidylserine to phosphatidylethanolamine. The observed stimulation of phosphatidylserine synthesis by amphiphilic cations was unaltered in protein kinase C (PKC) down-regulated cells and in retinoic acid (RA)-induced differentiated cells. In contrast, bis(2-ethylhexyl)hydrogen phosphate, an amphiphilic anion, strongly inhibited the incorporation of [3H]serine into phosphatidylserine. These observations demonstrate that phosphatidylserine synthesis in LA-N-2 cells can be modulated by amphiphilic cations and anions. It is suggested that the amphiphilic cations cause the ethanolamine moiety of membrane bound phosphatidylethanolamine to become more accessible to the juxtaposed serine base exchange enzyme.
Science & Sports
Introduction.—A new lever-propelled wheelchair prototype has been designed, which may avoid compl... more Introduction.—A new lever-propelled wheelchair prototype has been designed, which may avoid complications and discomfort related to the hand-rim conventional propulsion. Objective and method.—In the present investigation, this new prototype was evaluated objectively by the ‘‘Wheelchair Skills Training Program®’’. This test, proposed by the research team in the Dalhousie University, is a complete system which can be used in evaluation and training of manual wheelchair users and their caregivers. Results.—The results of the evaluation suggest that the prototype wheelchair is superior on a number of factors including such related to security and alteration in the propulsion technique. Nevertheless, some skills of our prototype were performed with failure. These individual skills are the ‘‘Gets over 15 cm pot-hole’’, ‘‘Rolls backward’’, ‘‘Gets from ground into wheelchair’’. © 2010 Elsevier Masson SAS. All rights reserved.
Celles que nous appelons les neurosciences sont un ensemble interdisciplinaires de multiples conn... more Celles que nous appelons les neurosciences sont un ensemble interdisciplinaires de multiples connaissances qui étudient les étroites relations existantes entre les fonctions du mental et celles du corps. L’influence de celui-ci dans le bien-être de celui-là et souvent dans l’amélioration de certaines pathologies, notamment cardiovasculaires, mais aussi hormonales, neurologiques, etc. est aujourd’hui bien reconnue. L’influence du mental sur le corps, vice-versa, a aussi pris un considérable essor au cours de la dernière vingtaine d’années grâce au développement de l’imagerie motrice et mentale en générale. Deux exemples sur l’influence certaine du mental sur le corps, seront ici donnés, basés sur les études développées ces dernières années dans notre laboratoire.
Journal of Neurochemistry
1,2-Diacyl-sn-glycerol (DAG) is a product of cell activation that has emerged as an important int... more 1,2-Diacyl-sn-glycerol (DAG) is a product of cell activation that has emerged as an important intracellular messenger whose primary function appears to be the activation of protein kinase C. They originate by the activation of phospholipases, which hydrolyze different phospholipids depending on the external stimulus and the nature of the cells, leading to the production of different molecular species. In the present study the quantitative changes in the total mass and the molecular species of DAG formed on phorbol ester (12-O-tetradecanoyl-phorbol 13-acetate) stimulation were investigated in proliferating and retinoic acid (RA)-differentiated human LA-N-1 cells. The TPA treatment of both cell types elicited an increase in the total amount of DAG. The increase was biphasic; i.e., an initial peak at 2-5 min was followed by a sustained increase that persisted for > 30 min. The analysis of the molecular species of DAG and phospholipids showed that in proliferating LA-N-1 cells, the D...
Advances in experimental medicine and biology, 1984
Life Sciences, 1972
... REFERENCES 1. RM HARDISTY and RS STACEY, J Physlol. Lond. 130; 711 (1955). 2. GVR BORN, 0. HO... more ... REFERENCES 1. RM HARDISTY and RS STACEY, J Physlol. Lond. 130; 711 (1955). 2. GVR BORN, 0. HORNYKIEWICZ, and A. STAFFORD, Br. J. Pharmacol. ... 15. CG. HAMMAR, I. HANIN, B. HOLMSTEDT, RJ KITZ, DJ JENDEN and B. KARLEN, Nature, Lond. 220: 915 (1968). ...
Clinical hemorheology and microcirculation, 2008
The aim of the study was to examine the effects of endurance exercise on circulating vascular cel... more The aim of the study was to examine the effects of endurance exercise on circulating vascular cell adhesion molecule-1 (sVCAM-1) and intercellular adhesion molecule-1 (sICAM-1) in sickle cell trait (SCT) athletes with or without alpha-thalassemia. Five athletes with SCT, 7 athletes with both SCT and alpha-thalassemia (SCTAT) and 8 control athletes (CONT) performed an incremental test on cycloergometer followed 72 hours later by a 60-min endurance exercise with a workload set at 70% P(peak) (peak power). We assessed levels of sICAM-1, sVCAM-1 and TNF-alpha at rest, immediately after endurance exercise and 1, 2, and 24 hours of recovery. Although, CONT and SCTAT groups exhibited similar basal plasma levels of adhesion molecules and TNF-alpha, SCT group had higher sVCAM-1 basal concentrations. No significant variation in sVCAM-1, sICAM-1 and TNF-alpha was measured following endurance exercise. Consequently, sVCAM-1 remained elevated in the SCT group after exercise and during the recove...
Cancer research, 1997
Mobile lipids have been detected by proton nuclear magnetic resonance (NMR) in animal and human t... more Mobile lipids have been detected by proton nuclear magnetic resonance (NMR) in animal and human tumors (cultured cells, biopsies, and in vivo), but their origin and subcellular location are still unclear. They have been associated with malignancy, metastatic ability, drug resistance, and necrosis. We wanted to determine whether these lipids are located within plasma membrane microdomains or in lipid droplets for a C6 cell-induced rat glioma. NMR-visible mobile lipids were found in all subcellular fractions isolated from the rat tumor, except in the cytosolic supernatants. Transmission electron microscopy showed that lipid droplets were present in all subcellular fractions containing NMR-visible lipids and in the necrotic and perinecrotic areas of the tumor. The mean diameter of droplets isolated by flotation in the subcellular fractionation protocol was 0.97 microm (n = 682; droplet profile diameter range between 0.2 and 5.0 microm). The apparent diffusion coefficient for these lipi...
Advances in biochemical psychopharmacology
Journal of Pharmacology and Experimental Therapeutics
Biochemical Society Transactions
Comptes rendus des séances de l'Académie des sciences. Série III, Sciences de la vie
Two kinetic mechanisms are responsible for the uptake of choline in Rat brain synaptosomal fracti... more Two kinetic mechanisms are responsible for the uptake of choline in Rat brain synaptosomal fractions with different affinity towards the substrate (high affinity mechanism: Km 5.1 microM, Vmax 44 pmol/mg prot/min.; low affinity mechanism: 35.7 microM, Vmax 286 pmol/mg prot/min). The treatment of synaptosomal fractions with neuraminidase (15 min. at 37 degrees C) followed by 1 min. incubation with various concentrations of [14C] choline reduces the uptake in parallel with the disappearance of the high affinity mechanism (Km 202.2 microM, Vmax 119 pmol/mg prot/min.), without influencing the synthesis of acetylcholine.
Comptes Rendus de l Académie des Sciences - Series III - Sciences de la Vie
A mixture of exogenous gangliosides at 10(-8) M and 10(-5) M concentration added to the medium of... more A mixture of exogenous gangliosides at 10(-8) M and 10(-5) M concentration added to the medium of chick neurons stimulates the metabolism of inositol compounds. Notably the incorporation of [3H] myo-inositol is increased in phosphatidylinositol and in inositol triphosphate. Gangliosides, hence, by increasing the production of second messengers might regulate the phosphorylation processes of neuronal proteins.
Birth defects original article series
ABSTRACT
Advances in Experimental Medicine and Biology
Comptes rendus des séances de l'Académie des sciences. Série III, Sciences de la vie
The existence of UDP-galactose:galactosyltransferase activities at the external surface of cultur... more The existence of UDP-galactose:galactosyltransferase activities at the external surface of cultured neurons from chick embryo hemispheres, was demonstrated. [14C]-galactose was transferred upon cellular substrates present on the neuronal surface and upon exogenous substrates (ovomucoïd) bound to Sepharose beads. The activity of ectogalactosyltransferase was not due to a leakage of intracellular enzymes into the incubation medium nor to an intracellular enzymatic activity utilizing [14C]-galactose obtained from the hydrolysis of UDP-[14C]-galactose. Kinetics of these ectogalactosyltransferases were analysed. The results support the hypothesis of a communication and/or interaction among the nerve cell surfaces via glycoconjugates or their biosynthetic enzymes.
Comptes Rendus de l Académie des Sciences - Series III - Sciences de la Vie
Several cell lines have been derived from an ocular melanoma obtained from an enucleated patient.... more Several cell lines have been derived from an ocular melanoma obtained from an enucleated patient. Three cell types are observed during the time in culture of all the cell lines under study. Two of them have epithelial and spindle shape respectively. A third cell type, having a spheroidal shape, is formed from spindle cells and may be transformed into epithelial cells upon re-seeding. Further experiments showed that the same cell may change of shape following the cycle: spheroidal-->epithelial-->fusiform-->spheroidal. Scanning microscopy shows the coexistence of the three cell shapes in the same culture and the presence of several filaments and processes protruding at the surface of the cells. Transmission electron microscopy shows that the cell lines, in general, contain melanosomes empty or fairly pigmented and several filaments and microtubules. The presence of melanin may be stimulated by seeding of melanoma cells over a "feeder layer" of fibroblasts.
Journal of lipid mediators
Several amphiphilic cations such as mepacrine, desipramine, didodecyldimethylamine, chlorpromazin... more Several amphiphilic cations such as mepacrine, desipramine, didodecyldimethylamine, chlorpromazine, oleylamine and W-7 activated the phospholipase D (PLD) activity of cultured LA-N-2 cells. These compounds, except for oleylamine, provoked the release of fatty acids, suggesting phospholipase A activation. Melittin, a PLA2 stimulator, caused the robust release of the free fatty acids but was a poor PLD activator. Although PLD could be activated by GTP gamma S, the stimulation by these amphiphilic cations was not abolished by GDP beta S, an inhibitor of G protein function. There was no change in the PLD activation by these amphiphilic cations by DiC8, a PKC activator, or by H-7, a PKC inhibitor or in PKC down-regulated cells.
Journal of lipid mediators
The stimulatory effects of sphingosine and oleylamine upon the incorporation of [3H]serine into i... more The stimulatory effects of sphingosine and oleylamine upon the incorporation of [3H]serine into its corresponding phospholipid, phosphatidylserine, by LA-N-2 cell cultures, have been reported (Singh et al. (1992) FEBS Lett., 296, 166-168). The presence of chlorpromazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) in cultures of these cells provoked increased phosphatidylserine synthesis but decreased protein synthesis in a concentration-dependent fashion. Several other amphiphilic cations, including dimethyldidodecylammonium bromide, verapamil, desipramine, amitriptyline, and mepacrine also stimulated phosphatidylserine synthesis in a dose-dependent manner. These amphiphilic cations reduced the conversion of phosphatidylserine to phosphatidylethanolamine. The observed stimulation of phosphatidylserine synthesis by amphiphilic cations was unaltered in protein kinase C (PKC) down-regulated cells and in retinoic acid (RA)-induced differentiated cells. In contrast, bis(2-ethylhexyl)hydrogen phosphate, an amphiphilic anion, strongly inhibited the incorporation of [3H]serine into phosphatidylserine. These observations demonstrate that phosphatidylserine synthesis in LA-N-2 cells can be modulated by amphiphilic cations and anions. It is suggested that the amphiphilic cations cause the ethanolamine moiety of membrane bound phosphatidylethanolamine to become more accessible to the juxtaposed serine base exchange enzyme.
Science & Sports
Introduction.—A new lever-propelled wheelchair prototype has been designed, which may avoid compl... more Introduction.—A new lever-propelled wheelchair prototype has been designed, which may avoid complications and discomfort related to the hand-rim conventional propulsion. Objective and method.—In the present investigation, this new prototype was evaluated objectively by the ‘‘Wheelchair Skills Training Program®’’. This test, proposed by the research team in the Dalhousie University, is a complete system which can be used in evaluation and training of manual wheelchair users and their caregivers. Results.—The results of the evaluation suggest that the prototype wheelchair is superior on a number of factors including such related to security and alteration in the propulsion technique. Nevertheless, some skills of our prototype were performed with failure. These individual skills are the ‘‘Gets over 15 cm pot-hole’’, ‘‘Rolls backward’’, ‘‘Gets from ground into wheelchair’’. © 2010 Elsevier Masson SAS. All rights reserved.
Celles que nous appelons les neurosciences sont un ensemble interdisciplinaires de multiples conn... more Celles que nous appelons les neurosciences sont un ensemble interdisciplinaires de multiples connaissances qui étudient les étroites relations existantes entre les fonctions du mental et celles du corps. L’influence de celui-ci dans le bien-être de celui-là et souvent dans l’amélioration de certaines pathologies, notamment cardiovasculaires, mais aussi hormonales, neurologiques, etc. est aujourd’hui bien reconnue. L’influence du mental sur le corps, vice-versa, a aussi pris un considérable essor au cours de la dernière vingtaine d’années grâce au développement de l’imagerie motrice et mentale en générale. Deux exemples sur l’influence certaine du mental sur le corps, seront ici donnés, basés sur les études développées ces dernières années dans notre laboratoire.
Journal of Neurochemistry
1,2-Diacyl-sn-glycerol (DAG) is a product of cell activation that has emerged as an important int... more 1,2-Diacyl-sn-glycerol (DAG) is a product of cell activation that has emerged as an important intracellular messenger whose primary function appears to be the activation of protein kinase C. They originate by the activation of phospholipases, which hydrolyze different phospholipids depending on the external stimulus and the nature of the cells, leading to the production of different molecular species. In the present study the quantitative changes in the total mass and the molecular species of DAG formed on phorbol ester (12-O-tetradecanoyl-phorbol 13-acetate) stimulation were investigated in proliferating and retinoic acid (RA)-differentiated human LA-N-1 cells. The TPA treatment of both cell types elicited an increase in the total amount of DAG. The increase was biphasic; i.e., an initial peak at 2-5 min was followed by a sustained increase that persisted for > 30 min. The analysis of the molecular species of DAG and phospholipids showed that in proliferating LA-N-1 cells, the D...
Advances in experimental medicine and biology, 1984
Life Sciences, 1972
... REFERENCES 1. RM HARDISTY and RS STACEY, J Physlol. Lond. 130; 711 (1955). 2. GVR BORN, 0. HO... more ... REFERENCES 1. RM HARDISTY and RS STACEY, J Physlol. Lond. 130; 711 (1955). 2. GVR BORN, 0. HORNYKIEWICZ, and A. STAFFORD, Br. J. Pharmacol. ... 15. CG. HAMMAR, I. HANIN, B. HOLMSTEDT, RJ KITZ, DJ JENDEN and B. KARLEN, Nature, Lond. 220: 915 (1968). ...
Clinical hemorheology and microcirculation, 2008
The aim of the study was to examine the effects of endurance exercise on circulating vascular cel... more The aim of the study was to examine the effects of endurance exercise on circulating vascular cell adhesion molecule-1 (sVCAM-1) and intercellular adhesion molecule-1 (sICAM-1) in sickle cell trait (SCT) athletes with or without alpha-thalassemia. Five athletes with SCT, 7 athletes with both SCT and alpha-thalassemia (SCTAT) and 8 control athletes (CONT) performed an incremental test on cycloergometer followed 72 hours later by a 60-min endurance exercise with a workload set at 70% P(peak) (peak power). We assessed levels of sICAM-1, sVCAM-1 and TNF-alpha at rest, immediately after endurance exercise and 1, 2, and 24 hours of recovery. Although, CONT and SCTAT groups exhibited similar basal plasma levels of adhesion molecules and TNF-alpha, SCT group had higher sVCAM-1 basal concentrations. No significant variation in sVCAM-1, sICAM-1 and TNF-alpha was measured following endurance exercise. Consequently, sVCAM-1 remained elevated in the SCT group after exercise and during the recove...
Cancer research, 1997
Mobile lipids have been detected by proton nuclear magnetic resonance (NMR) in animal and human t... more Mobile lipids have been detected by proton nuclear magnetic resonance (NMR) in animal and human tumors (cultured cells, biopsies, and in vivo), but their origin and subcellular location are still unclear. They have been associated with malignancy, metastatic ability, drug resistance, and necrosis. We wanted to determine whether these lipids are located within plasma membrane microdomains or in lipid droplets for a C6 cell-induced rat glioma. NMR-visible mobile lipids were found in all subcellular fractions isolated from the rat tumor, except in the cytosolic supernatants. Transmission electron microscopy showed that lipid droplets were present in all subcellular fractions containing NMR-visible lipids and in the necrotic and perinecrotic areas of the tumor. The mean diameter of droplets isolated by flotation in the subcellular fractionation protocol was 0.97 microm (n = 682; droplet profile diameter range between 0.2 and 5.0 microm). The apparent diffusion coefficient for these lipi...