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Biomedical subjects

G Roblin

Publications and source records attributed to G Roblin.

9 recordsLinked to original sources
PubMed2005

Validity of sleep nasendoscopy in the investigation of sleep related breathing disorders.

OBJECTIVE: To validate the technique of sleep nasendoscopy using target controlled infusion in symptomatic patients and a control group of asymptomatic individuals. DESIGN: Prospective cohort study. SETTING: Department of otolaryngology-head and neck surgery and anesthesia in a teaching hospital. PARTICIPANTS: Two groups of patients were compared and matched for their body mass index. The first group consisted of 53 patients with a history suggestive of obstructive sleep apnea. The second group consisted of 54 patients with partner-confirmed history of no snoring. These patients were undergoing anesthesia for other reasons. Both groups of patients were free of associated otorhinolaryngologic symptoms. MAIN OUTCOME MEASURE: Assessment of production of snoring or obstruction in patients with no documented history of snoring when sedation was administered as part of general anesthesia using target controlled infusion with propofol. RESULTS AND CONCLUSIONS: None of the patients in the asymptomatic group snored or obstructed at any level of propofol, and this was clearly significant on comparison with the symptomatic group (P < .001). All of the symptomatic patients were induced to become symptomatic (snoring/obstruction).

Body Mass Index↗
PubMed1998

Regulation of a plant plasma membrane sucrose transporter by phosphorylation.

The protein phosphatase inhibitor okadaic acid (OA) either provided directly to sugar beet (Beta vulgaris L.) leaf discs or infiltrated in the leaf blade rapidly inhibited sucrose uptake. Methyl okadaic acid, a biologically inactive analogue of OA, had only a marginal effect on uptake. OA inhibited proton-motive force-driven uptake of sucrose into plasma membrane vesicles, without affecting their proton permeability. OA did not significantly affect the amount of sucrose transporters present in the vesicles, as estimated by ELISA with specific antibodies. It is concluded that OA directly inhibits the activity of a H+-sucrose cotransporter of the plant plasma membrane, likely by maintaining it in a phosphorylated form.

4-Chloromercuribenzenesulfonate↗
PubMed1989

Effects of Compounds Affecting Calcium Channels on Phytochrome- and Blue Pigment-Mediated Pulvinar Movements of Cassia fasciculata.

Verapamil and nifedipine, known as calcium channel blockers, inhibited the phytochrome-mediated movements induced on Cassia fasciculata leaflets by a light-off signal, whereas they had no effect on the ;blue' pigment-mediated movements induced by a light-on signal. LaCl(3) inhibited both types of reactions, but the inhibition of light-induced opening needed a 10 times higher concentration than that of dark-induced closure. Bay K 8644, an activator of calcium channels, increased the rate of dark-induced closure, whereas it had no effect on the light-induced opening. These data suggest that calcium ions are not mobilized in the same way in the two types of movements: possibly from external stores in the phytochrome-mediated reaction and from internal stores in the ;blue' pigment-mediated reaction.

Journal Article↗
PubMed1986

Effects of Respiration Inhibitors and Uncouplers on Dark- and Light-Induced Leaflet Movements of Cassia fasciculata.

Respiration inhibitors, in particular KCN and NaN(3), inhibited slightly the dark-induced (scotonasty) as well as the light-induced (photonasty) leaflet movements of Cassia fasciculata: they act only at concentrations higher than 1 millimolar and 0.1 millimolar, respectively. Amytal induced a stronger inhibitory effect on scotonasty. Salicylhydroxamic acid, which inhibits the cyanide-insensitive respiration pathway, was also poorly effective when applied alone. KCN and salicylhydroxamic acid applied together increased the inhibition. Uncouplers of oxidative phosphorylation were very effective: 2,4-dinitrophenol and carbonylcyanide-m-chlorophenylhydrazone inhibited the scotonastic movements at concentrations higher than 10 mum and 1 mum, respectively. Although uncouplers reduced the photonastic movements at higher concentrations, they promoted leaflet opening at other concentrations in an unexpected way.

Journal Article↗
PubMed1985

A visual technique of chemotactic assessment for pharmacological studies.

A visual assay of chemotactic response was performed by measuring the extent of the migration of polymorphonuclear leukocytes (PMN) collected from the rat pleural cavity toward a dying cell. Various types of cells (erythrocytes, PMN, or monocytes) may be destroyed by means of an argon laser, and the process may be visualized under a phase-contrast microscope (necrotactic phenomenon). This experimental model may simulate pathological events that occur in damaged tissues, and it permits the study of cellular migration during inflammatory diseases. This method did not seem to involve chemokinetic effects, but instead represented a true measure of chemotaxis. A numeration of the migrating PMNs at t = 0 and t + 10 min after cell lysis allowed a statistical analysis and the use of this phenomenon for pharmacological studies. The modification of rat PMN chemotaxis by cholera toxin, substance P, and a synthetic muramyl dipeptide are presented as examples of the use of this technique.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1985

Effects of Ethephon, 1-Aminocyclopropane-1-carboxylic Acid, and Inhibitors of Ethylene Synthesis on the Gravitropically Induced Movement of Mimosa pudica Pulvinus.

Primary pulvini of Mimosa pudica L. displaced from their position display gravitropic movements beginning about 15 minutes after their reorientation. Ethephon, an ethylene-releasing compound, and 1-aminocyclopropane-1-carboxylic acid, an intermediate in ethylene biosynthesis, enhance these movements at a concentration as low as 10 nanomolar. Inhibitors of ethylene synthesis (l-alpha-(2-aminoethoxyvinyl)glycine, (aminooxy)acetic acid, and Co(2+)) reduce the amplitude of the movements. The promotive action of 1-aminocyclopropane-1-carboxylic acid is abolished by l-alpha-(2-aminoethoxyvinyl)glycine. These results permit one to conclude that ethylene may modify the curvature movement but not the initiation of the gravitropic reaction. With reference to the pulvinus functioning based on turgor variations and ion migrations inside the organ, namely K(+) acting as the osmoticum, the data suggest that ethylene may act by increasing the membrane permeability to water and/or by altering an ion pump.

Journal Article↗
PubMed1984

Effects of Salicylic and Acetylsalicylic Acids on the Scotonastic and Photonastic Leaflet Movements of Cassia fasciculata.

Salicylic and acetylsalicylic acids applied on excised leaves of Cassia fasciculata modify the dark-induced (scotonastic) and light-induced (photonastic) leaflet movements. They inhibit the scotonastic movements in a dose-dependent manner from 1 x 10(-4) to 1 x 10(-3) molar and they promote the photonastic movements at an optimum concentration of 5 x 10(-4) molar. These results suggest that these phenolic compounds do not act specifically on the K(+) uptake, which was shown to be inhibited by their action on other materials.

Journal Article↗