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E Rousseau

Publications and source records attributed to E Rousseau.

At least 91 records · Page 5Linked to original sources
PubMed1988

Evidence for a Ca2+ channel within the ryanodine receptor complex from cardiac sarcoplasmic reticulum.

The solubilized [3H]ryanodine receptor from cardiac sarcoplasmic reticulum was centrifuged through linear sucrose gradients. A single peak of radioactivity with apparent sedimentation coefficient of approximately 30S specifically comigrated with a high molecular weight protein of apparent relative molecular mass approximately 400,000. Incorporation of the ryanodine receptor into lipid bilayers induced single Ca2+ channel currents with conductance and kinetic behavior almost identical to that of native cardiac Ca2+ release channels. These results suggest that the cardiac ryanodine receptor comprises the Ca2+ release channel involved in excitation-contraction coupling in cardiac muscle.

Animals↗
PubMed1988

Purification and reconstitution of the calcium release channel from skeletal muscle.

The calcium release channel from rabbit muscle sarcoplasmic reticulum (SR) has been purified and reconstituted as a functional unit in lipid bilayers. Electron microscopy reveals the four-leaf clover structure previously described for the 'feet' that span the transverse tubule (T)-SR junction. Ca2+ release from the SR induced by T-system depolarization during excitation-contraction coupling in muscle may thus be effected through a direct association of the T-system with SR Ca2+-release channels.

Animals↗
PubMed1988

Properties of single chloride selective channel from sarcoplasmic reticulum.

The behavior of single chloride channels in sarcoplasmic reticulum of rabbit and trout skeletal muscle was examined by fusing isolated vesicle fractions into planar lipid bilayers. The channel exhibited a full open state with a unit conductance of 65 pS (in 100 mM Cl-) and several subconductance states with reversal potentials which were dependent on the chloride gradient across the bilayer. Open probability was 0.6-0.95 for membrane potentials ranging from -60 to +60 mV. The kinetic behaviour could be described by assuming one time constant for the fully conducting channel, and at least two time constants for the non-conducting channel. In the presence of methane sulfonate, sulfate and phosphate anions, a decrease in the unit current amplitude but not open time argued in favor of a competition between these anions and Cl- at the transport site of the channel. Chloride channel activity was not affected by variations of Ca2+ concentration in both chambers or by the presence of Mg2+. Similarly, neither millimolar ATP nor the presence of the drugs taurine (up to 10 mM), lidocaine (2-40 microM) or the calmodulin antagonist W7 (5-150 microM), modified channel behavior. Finally, pH variations between 6.8 to 8 were without effect.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1988

Renal complications of acquired immunodeficiency syndrome in children.

A low incidence of renal disease was noted in a retrospective analysis of pediatric patients with acquired immunodeficiency syndrome. Episodes of acute renal failure were attributable to dehydration or nephrotoxicity. One patient, however, had nephrosis with focal glomerular sclerosis. Focal sclerosis involving 10% to 20% of glomeruli was evident in autopsy tissue from three patients.

Acquired Immunodeficiency Syndrome↗
PubMed1988

[Comparative efficacy of endoscopic sclerosis of esophageal varices by intravariceal injection of polidocanol and perivariceal injection of quinine-urea].

Concerned by mortality due to recurrent bleeding and associated risk factors in cirrhotic patients, we attempted to compare the efficiency of perivascular sclerotherapy using quinine urea with that of intravascular polidocanol and to determine the predictive factors of clinical outcome. Of 74 patients admitted for bleeding esophageal varices, 31 were treated with perivascular sclerotherapy (group I), and 43 with intravascular sclerotherapy (group II). Three months later, only 63 p. 100 of patients in group I had not rebled, compared to 90 p. 100 of patients in group II (p less than 0.001). After 6 months, no significative difference was found between the two groups. The one year survival rate was 44 p. 100 in group I and 79 p. 100 in group II (p less than 0.002). Encephalopathy and ascites were found to be predictive factors of mortality, whereas neither clinical or biologic factors were found to be predictive for recurrent bleeding. These results suggest that in esophageal sclerotherapy, the intravascular route with polidocanol provides earlier results and a better one year survival rate, compared with the perivascular route. However, survival rates depend on encephalopathy and ascites criteria.

Drug Combinations↗
PubMed1988

Hemolytic uremic syndrome: urate nephropathy superimposed on an acute glomerulopathy? An hypothesis.

The oligo-anuria of the hemolytic uremic syndrome is attributed to the presence of a renal lesion which is predominantly glomerulopathic but which may have a vasculopathic component of varying severity. Fourteen children, four of whom had anuric, four oliguric and six non oliguric acute renal failure were treated with intravenous fluids and high dose intravenous furosemide therapy. Polyuria was induced in all, obviating the need for dialysis. We hypothesize that oligo-anuria in this syndrome may be due to the previously recognized hyperuricemia causing a urate nephropathy superimposed on the glomerulopathy thus explaining its possible amenability to fluid and diuretic therapy.

Acute Kidney Injury↗
PubMed1987

Ryanodine modifies conductance and gating behavior of single Ca2+ release channel.

Ryanodine affects excitation-contraction coupling in skeletal and cardiac muscle by specifically interacting with the sarcoplasmic reticulum (SR) Ca2+ release channel. The effect of the drug at the single channel level was studied by incorporating skeletal and cardiac SR vesicles into planar lipid bilayers. The two channels were activated by micromolar free Ca2+ and millimolar ATP and inhibited by Mg2+ and ruthenium red. Addition of micromolar concentrations of ryanodine decreased about twofold the unit conductance of the Ca2+- and ATP-activated skeletal and cardiac channels. A second effect of ryanodine was to increase the open probability (Po) of the channels in such a way that Po was close to unity under a variety of activating and inactivating conditions. The effects of ryanodine were long lasting in that removal of ryanodine by perfusion did not return the channels into their fully conducting state.

Alkaloids↗
PubMed1986

[Reason for admission and cause of death in a multidisciplinary pediatric intensive care unit].

In contrast with neonatal intensive care services, paediatric intensive care units are relatively new; thus, it is not surprising that their clientele has not been well described in the medical literature. In order to better define it, we did a retrospective analysis of 4646 consecutive admissions of children aged between a week and 18 years to a multidisciplinary paediatric intensive care unit over a period of five years (1979-83). This unit belongs to a 700-bed paediatric hospital delivering medical as well as surgical tertiary care. Of the 4646 admissions, 2527 (54.3 per cent) were surgical and 2119 (45.6 per cent) medical. There were multiple diagnoses on admission. Among the most frequent diagnoses were major trauma (9.6 per cent of total), intoxications (4.6 per cent) and congenital cardiopathies in the postoperative phase of a corrective or palliative surgery (tetralogy of Fallot (2.8 per cent), ASD (2.7 per cent), etc.) The global mortality rate was 5.8 per cent (268/4646). Severe infections and cardiopathies, mostly congenital, were responsible for almost half the deaths (24.2 per cent each). This description of patients and problems encountered in a paediatric intensive care unit should facilitate planning for personnel training and can be used to establish guidelines for reducing mortality.

Adolescent↗
PubMed1986

Single channel and 45Ca2+ flux measurements of the cardiac sarcoplasmic reticulum calcium channel.

Purified canine cardiac sarcoplasmic reticulum vesicles were passively loaded with 45CaCl2 and assayed for Ca2+ releasing activity according to a rapid quench protocol. Ca2+ release from a subpopulation of vesicles was found to be activated by micromolar Ca2+ and millimolar adenine nucleotides, and inhibited by millimolar Mg2+ and micromolar ruthenium red. 45Ca2+ release in the presence of 10 microM free Ca2+ gave a half-time for efflux of 20 ms. Addition of 5 mM ATP to 10 microM free Ca2+ increased efflux twofold (t1/2 = 10 ms). A high-conductance calcium-conducting channel was incorporated into planar lipid bilayers from the purified cardiac sarcoplasmic reticulum fractions. The channel displayed a unitary conductance of 75 +/- 3 pS in 53 mM trans Ca2+ and was selective for Ca2+ vs. Tris+ by a ratio of 8.74. The channel was dependent on cis Ca2+ for activity and was also stimulated by millimolar ATP. Micromolar ruthenium red and millimolar Mg2+ were inhibitory, and reduced open probability in single-channel recordings. These studies suggest that cardiac sarcoplasmic reticulum contains a high-conductance Ca2+ channel that releases Ca2+ with rates significant to excitation-contraction coupling.

Animals↗
PubMed1986

Group A streptococcal supraglottitis.

We describe four children with severe supraglottic infections caused by group A beta-hemolytic streptococci. In each case the clinical presentation suggested Hemophilus influenzae epiglottitis. In only one patient was there significant involvement of the epiglottis, whereas all had striking inflammation of the aryepiglottic folds. Group A beta-hemolytic streptococcus was isolated in blood cultures in two patients and from the supraglottic area and trachea in two others. Fever persisted for 6 to 22 days, and tracheal intubation was necessary for 2 to 16 days, despite appropriate antibiotic therapy. The evolution of streptococcal supraglottitis may be protracted, and it must be managed accordingly.

Child↗
PubMed1985

Single-channel analysis of a potassium inward rectifier in myocytes of newborn rat heart.

Unitary K+ currents in single cells isolated from ventricular muscle of newborn rat hearts were measured in response to different potentials and [K]o. The I/V curves were linear for potentials more negative than the zero-current voltage; especially in high [K]o (150 mM KCl), no clear outward currents could be detected indicating a drastic rectification in the inward direction. The channel is mainly selective to K+ but Na+ ions are also carried (PNa/PK = 0.056). The channel conductance is proportional to the square root of [K]o but Na+ ions seem to have a facilitatory effect on gamma K, the single-channel conductance. The channel activity, measured as Po, i.e. the probability to find the channel in open state, decreased as the membrane was hyperpolarized. This behavior was tentatively explained by an inactivation process as the membrane becomes more negative. The rate constants of the transitions between the different states were calculated according to a C-O-C model. A control of the gating process by permeant ion K+ was postulated, based on the increase of one of the rate constants from the closed to the open state with [K]o. Finally, the macroscopic I/V curves calculated from Po and delta i, the unit current, were found to be characteristic of a ion-blocked inward rectifier.

Animals↗
PubMed1985

[Prospective study of 64 cases of Kawasaki's disease].

We prospectively studied 64 children with Kawasaki disease. The well recognized signs were seen, but we also found hyperemia of the tympanic membrane in 27%, uveitis in 17%, syndrome of inappropriate secretion of anti-diuretic hormone in 9%, hydrops of the gallbladder in 8%, pulmonary infiltrations in 5% and one death. One patient presented with acute kidney failure, another one presented with stenosis of the renal artery, and 8 presented white blood cells (WBC) in the urinary sediment. Sedimentation was accelerated and there was an important decrease in hemoglobin blood level around the 5th day of illness. The WBC count rose around the 10th day; thereafter, all these results returned to normal while platelets counts rose. Albumin blood level was low, and all the following data were higher than normal: alpha-1-globulin, alpha-2-globulin, IgA, IgM, SGOT, SGPT, bilirubin and CRP. Viral studies were performed in 37 patients; 12 showed positive results.

Blood Cell Count↗