Type II hyperprolinaemia with renal involvement.
Explore the source record for details and available documents.
Amino Acid Metabolism, Inborn Errors↗
Biomedical subjects
D Morin
Publications and source records attributed to D Morin.
A method to measure simultaneously cyclic AMP and inositol phosphate accumulation in rat brain slices.
The simultaneous measurement of the accumulation of cyclic AMP and inositol phosphates in rat cerebral cortical slices is described. After stimulation, the separation of cyclic AMP and inositol phosphates was achieved using ion-exchange chromatography and their concentrations were determined by means of a double-labeling technique, the substrates adenine and inositol being labeled with 14C and 3H, respectively. The recoveries were 70-80% for inositol phosphates and 40-50% for cyclic AMP. To test the applicability of the method, norepinephrine was chosen as an agonist, because it is known to stimulate the production of these two second messengers by interacting with alpha- and beta-adrenergic receptors. This procedure is an improvement over existing methods, because we obtained the simultaneous formation of 3H-inositol phosphates and [14C]cyclic AMP in a concentration-dependent process. EC50 values were similar for the two, 8.5 +/- 3.9 microM for 3H-inositol phosphates and 20.2 +/- 6.3 microM for [14C]cyclic AMP, and close to the values obtained when each process was studied alone. The action of adrenergic antagonists was also tested. Propranolol blocked the norepinephrine stimulation of [14C]cyclic AMP, but did not inhibit the norepinephrine stimulation of 3H-inositol phosphates. The opposite results were observed with prazosin. Our results suggest that this method could be a useful tool to examine the interaction between these two receptor-coupled effectors.
1-Methyl-3-isobutylxanthine↗
Interactions of flerobuterol, an antidepressant drug candidate, with beta adrenoceptors in the rat brain.
Interactions of dl-flerobuterol with central beta adrenoceptors were investigated. It inhibited the binding of [3H]CGP 12177, a selective beta adrenoceptor ligand, to membranes prepared from rat cerebral cortex, cerebellum, heart and lung. The affinity of dl-flerobuterol was very close in all tissues (Ki approximately 1 microM). In cerebral cortex, binding inhibition of [3H]CGP 12177 was stereospecific, l-flerobuterol (Ki = 483 nM) being 70-fold more potent than d-flerobuterol (Ki = 34 microM). Moreover, dl-flerobuterol (Ki = 926 nM) was 7-fold less potent than isoproterenol (Ki = 140 nM) to displace [3H]CGP 12177 binding, but 5-fold more potent than salbutamol (Ki = 4600 nM). Flerobuterol did not inhibit the radioligand binding to the other receptors at the highest concentration tested, thus leading to a very high beta adrenergic selectivity. Flerobuterol increased the concentration of cyclic AMP in slices of rat cerebral cortex in a dose-dependent manner; this effect was antagonized by atenolol and propranolol. Compared to isoproterenol or norepinephrine, which produced cyclic AMP maximal increases of 380 and 460%, respectively, it showed a weaker activity with a maximal stimulation obtained at 100 microM, corresponding to a cAMP increase of 140% over basal value (100%). These data revealed that flerobuterol possessed a beta adrenergic agonist activity. Moreover, it antagonized competitively the isoproterenol- or norepinephrine-stimulated accumulation of cAMP. At low concentrations of isoproterenol or norepinephrine, the stimulation of adenylate cyclase was only due to the action of flerobuterol, but at higher concentrations, the response of isoproterenol or norepinephrine was competitively blocked by flerobuterol. At 10 microM, isoproterenol surmounted fully this antagonism.(ABSTRACT TRUNCATED AT 250 WORDS)
Adrenergic beta-Antagonists↗
[Transitory acute kidney insufficiency and insulin-dependent after treatment of kala-azar with pentamidine and N-methylglucamine antimony].
Azotemia and diabetes mellitus are now well-known adverse reactions associated with Pentamidine treatment, especially since its prescription in case of Pneumocystis carinii pneumonia. We report the case of a 2 year-old boy, treated for kala-azar with pentamidine and N-methyl glucamine antimoniate who developed adverse effects, characterized by a nephrotic syndrome associated with the classic acute tubular necrosis, and transient diabetes mellitus.
Acute Kidney Injury↗
Blood binding of selezen (imidazole salicylate) in man.
The interactions of selezen (imidazole salicylate) with human blood components were studied by equilibrium dialysis. These interactions were limited to the binding of salicylate to human serum albumin (HSA). The binding was saturable and involved several classes of binding sites with different association constants. A competition study indicated that salicylic acid at high concentration was able to displace warfarin and digitoxin but not glibenclamide from their HSA sites. On the other hand, selezen serum binding was decreased in renal impaired patients and this result was probably linked to the decreases in HSA concentration. So the use of small dosage regimens of selezen to these patients can be proposed. The same recommendation may be done for cirrhotic patients, where the decrease of selezen binding percentage was observed and due to both hypoalbuminemia and hyperbilirubinemia.
Anti-Inflammatory Agents, Non-Steroidal↗
Metabolism and cytotoxicity of naphthalene oxide in the isolated perfused mouse lung.
Naphthalene produces selective injury to Clara cells in the mouse in vivo and in the isolated perfused lung. To investigate the role of circulating reactive metabolites in lung injury, the stability, metabolism and cytotoxicity of naphthalene oxide, a reactive intermediate, were examined in the perfused mouse lung. The T1/2 of naphthalene oxide is 4 min in Waymouth's medium. Addition of 5% bovine serum albumin to the medium increased the half-life of the epoxide to 11 min. Perfusion of the lung with 0.2 or 2 mumol of naphthalene oxide decreased pulmonary reduced glutathione levels to 62 and 42% of control, respectively. 1,4-Naphthoquinone and naphthol-glucuronide represented 36 and 25% of the total polar metabolites isolated after infusion of naphthalene oxide, whereas dihydrodiol and thioether conjugates were minor metabolites. In comparison, thioethers and dihydrodiol were the primary metabolites isolated from lungs perfused with [14C]naphthalene. Histologic examination of the lungs fixed 4 hr after infusion of naphthalene oxide (0.25-1.0 mumol/60 min) revealed selective vacuolation and necrosis of Clara cells, significant decreases in the mass of bronchiolar Clara cells and increases in the mass of vacuolated cells. Injury to lungs perfused with naphthalene or secondary metabolites such as naphthoquinones, 1-naphthol and 1,2-dihydro-1,2-dihydroxynaphthalene was less dramatic. In contrast to other studies implicating quinones as mediators of aromatic hydrocarbon toxicity, the current work suggests that epoxides play a significant role in naphthalene-induced lung injury. This investigation also demonstrates that circulating epoxides are capable of eliciting selective Clara cell injury.
Animals↗
The influence of various drugs on the binding of tianeptine to human plasma proteins.
The plasma binding of the atypical tricyclic antidepressant tianeptine was studied in combination with six drugs, at therapeutic concentrations: cyamemazine, levomepromazine, flunitrazepam, oxazepam, diclofenac and salicylic acid. Of these drugs, only salicylic acid at high plasma concentrations impaired tianeptine binding and thus may potentiate its effects.
Anti-Inflammatory Agents, Non-Steroidal↗
Serotonergic influences on central respiratory activity: an in vitro study in the newborn rat.
The in vitro brainstem-spinal cord of the newborn rat has been used to study the central effects of serotonin (5-HT) on the brainstem respiratory motor control system. Brainstem superfusion with a medium containing 5-HT (30 microM) induced a short latency increase of respiratory frequency, often (60% of the experiments) followed by delayed tonic activity. Weaker concentrations of 5-HT (10-20 microM) were ineffective but prior application of drugs limiting 5-HT inactivation (pargyline and fluoxetine) revealed 5-HT effects. Changes in respiratory frequency are: (1) completely antagonized by methysergide; (2) not suppressed by 5-HT2 (ketanserine) and 5-HT3 (zacopride, GR3832F) antagonists; and (3) induced by 5-HT1 agonists (RU24969, buspirone). Since 5-HT2 agonists (DOI, alpha-methyl-5-HT) only evoked minor changes in frequency, the central action of 5-HT on the respiratory rhythm generator seems to depend on activation of 5-HT1 receptors. Tonic activity induced by 5-HT is: (1) antagonized by methysergide or ketanserine but not 5-HT3 antagonists; (2) induced by 5-HT2 but not 5-HT1 agonists; (3) still induced in the isolated spinal cord by 5-HT superfusion or 5-HT microinjection in the cervical ventral horn; and (4) sometimes replaced by rhythmic activity at a frequency different from that of respiration. Tonic activity does not involve the central circuitry responsible for respiration but depends on 5-HT2 receptors linked to spinal networks. These results suggest that 5-HT exerts a facilitory modulation on the respiratory rhythm generator through 5-HT1 medullary receptors and on motoneurons through 5-HT2 spinal receptors.
Animals↗
Depressant effect of raphe stimulation on inspiratory activity of the hypoglossal nerve: in vitro study in the newborn rat.
Respiratory activity was recorded from the hypoglossal nerve and cervical ventral roots of the superfused isolated brainstem and spinal cord of the newborn rat in order to investigate the effects of serotonin (5-HT). Three experimental procedures were used: (i) brainstem superfusion by exogenous 5-HT (previously reported), (ii) electrical stimulation of pontine midline structures, and (iii) pressure microejection of L-glutamate at the same sites. Each of the experimental procedure increased respiratory frequency and depressed the amplitude of the discharge of the hypoglossal nerve more than that of the cervical roots. These results indicate that 5-HT acts centrally to modulate the activity of the respiratory generator and inhibits the hypoglossal activity. A possible involvement of 5-HT mediated inhibition in obstructive apnea is discussed.
Animals↗
Increased percolation threshold for 100-K superconductivity in lead-substituted Bi-Sr-Ca-Cu-O thin films.
Explore the source record for details and available documents.
Journal Article↗
17O NMR spectroscopy of Bi2Sr2CaCu2O8+x high-Tc superconductor.
Explore the source record for details and available documents.
Journal Article↗
Differential effects of serotonin on respiratory activity of hypoglossal and cervical motoneurons: an in vitro study on the newborn rat.
Newborn rat respiratory activity was recorded on hypoglossal nerve and ventral cervical roots during in vitro experiments performed on superfused brainstem spinal cord preparations. The addition of serotonin (5-HT) to the bathing medium increased the respiratory frequency and selectively depressed the hypoglossal activity. Any decreases in the amplitude of cervical recordings were always restricted and reversible, whereas the hypoglossal activity was abolished. Furthermore, on cervical roots, 5-HT induced a tonic activity superimposed on the respiratory one, which was never observed with the hypoglossal nerve. When 5-HT was applied on isolated hemispinal cord, a tonic activity could still be elicited. These results indicate that serotonin (i) modulates the activity of neurons involved in the generation of respiratory rhythm, (ii) depresses the activity of hypoglossal motoneurons, and (iii) evokes tonic activity in cervical motoneurons, probably as the result of direct spinal effects.
Action Potentials↗
Functional significance of the dorsal respiratory group in adult and newborn rats: in vivo and in vitro studies.
The involvement of the dorsal part of the medulla (the so-called dorsal respiratory group: DRG) in the networks participating in respiratory function was investigated in newborn (in vitro) and adult (in vivo) rats. In the dorsal part of the medulla of the isolated brainstem of newborn rats, no respiratory neurons were found and stimulations or lesions neither modified nor suppressed the respiratory output. On the contrary, similar experiments suggest that sites in the ventral medulla have a fundamental importance for respiration. In adult rats, lesion of the DRG areas by electrocoagulation induced transient changes in respiratory timing, and resulted in a significant decrease in the amplitude of the contralateral phrenic output. These results suggest that the dorsal part of the medulla is not involved in controlling respiratory activity in the newborn rat. In adults, no definite conclusion can be reached, but the functional role of the DRG, if any, is probably restricted.
Action Potentials↗
Lyme disease: first indigenous case in Quebec.
Explore the source record for details and available documents.
Adult↗
Characterization of arsenopyrite oxidizing Thiobacillus. Tolerance to arsenite, arsenate, ferrous and ferric iron.
Two strains of Thiobacillus, T. ferrooxidans and T. thiooxidans, have been isolated from a bacterial inoculum cultivated during a one-year period in a 1001 continuous laboratory pilot for treatment of an arsenopyrite/pyrite concentrate. The optimum pH for the growth of both strains has been found to be between 1.7 and 2.5. Because of the high metal toxicity in bioleach pulps, the tolerance of T. ferrooxidans and T. thiooxidans with respect to iron and arsenic has been studied. The growth of both strains is inhibited with 10 g/l of ferric ion, 5 g/l of arsenite and 40 g/l of arsenate. 20 g/l of ferrous iron is toxic to T. ferrooxidans but 30 g/l is necessary to impede the growth of T. thiooxidans.
Acidithiobacillus thiooxidans↗
Acetylcholine and central chemosensitivity: in vitro study in the newborn rat.
In vitro experiments were performed in the superfused brainstem-spinal cord preparation of newborn rats in order to analyse the central respiratory effects of acetylcholine. The central motor output was assessed from recording electrical activity in nerves supplying respiratory muscles. Acetylcholine added to the bathing medium induced dose-dependent increases in respiratory frequency which were blocked by muscarinic (but not nicotinic) antagonists and enhanced by physostigmine. These effects originated from the medullary ventral surface where chemosensitive structures have been previously located. The respiratory central chemosensitivity of the isolated brainstem was analysed using a CO2 free, pH 7.9 medium instead of the normal medium (bubbled with 5% CO2, pH 7.3). Decreases at the H+ and CO2 stimuli led to decreased inspiratory activity, resulting mainly from a decrease in the amplitude of the motor output. These responses were enhanced by atropine and diminished by physostigmine. These results obtained in vitro on the newborn rat suggest that cholinergic synapses are not directly involved in the genesis of respiratory rhythmicity but confirm previous results obtained in vivo in adult animal revealing that acetylcholine is implicated in the central respiratory chemosensitivity.
Acetylcholine↗
Isolation and identification of a pyrrolic glutathione conjugate metabolite of the pyrrolizidine alkaloid monocrotaline.
This report describes the isolation and identification of a monocrotaline-derived, glutathione-conjugated pyrrole obtained from the bile of male Sprague-Dawley rats. Bile obtained from rats given an intravenous bolus of 14C-monocrotaline was fractionated using a series of chromatographic separations. Initial purification with cholestyramine resin removed bile acid and pigment contaminants. Subsequent anion exchange and reversed-phase HPLC separations yielded several fractions that contained the 14C label and tested positive for pyrroles using Ehrlich's reagent. These fractions were analyzed using fast-atom-bombardment tandem mass spectrometry (FAB MS/MS). In addition to glutathione-conjugated dehydroretronecine, at least one other pyrrole present had similar ionic properties. The latter was not present in amounts sufficient for positive identification.
Animals↗
Tianeptine binding to human plasma proteins and plasma from patients with hepatic cirrhosis or renal failure.
1. The binding of tianeptine to human plasma, isolated plasma proteins, red blood cells and to plasma from patients with cirrhosis or renal failure was studied in vitro by equilibrium dialysis. 2. Tianeptine is highly bound to plasma (95%) at therapeutic concentrations (0.3-1 microM). No saturation of the binding sites was seen. 3. Human serum albumin (HSA) was shown to be mainly responsible for this binding (94%) with a saturable process characterized by one binding site with a moderate affinity (Ka = 4.2 x 10(4) M-1) and a non-saturable process with a low total affinity (nKa = 1.2 x 10(4) M-1). 4. Like many basic and amphoteric drugs, tianeptine showed a saturable binding to alpha 1-acid glycoprotein (AAG) with one site and a moderate affinity (Ka = 3.7 x 10(4) M-1). Its binding to lipoproteins and red blood cells (RBC) was weak and non-saturable. Over the range of therapeutic drug concentrations (0.3-1 microM), the unbound fraction in blood remains constant (4.5%). 5. Interactions were studied using non-esterified fatty acids (NEFA) at pathological concentrations; they altered tianeptine binding to plasma and to isolated HSA. Tianeptine seems to bind to a HSA site different from sites I (warfarin) and II (diazepam), but close to site II. It also shares the only basic-site on AAG. However, at therapeutic drug concentrations (0.3-1 microM), not all of these interactions occur. 6. The binding of tianeptine varied according to HSA, AAG and NEFA concentrations both in patients and healthy subjects. In patients with chronic renal failure having high NEFA concentrations the unbound fraction of tianeptine (fu) increased from 0.045 to 0.153 compared with normal (P less than 0.001). In cirrhotic patients, with relatively low HSA concentrations, the fu of tianeptine increased from 0.045 to 0.088 compared with normal (P less than 0.01). 7. Multiple regression analysis of all of the data indicated that the fu of tianeptine was related significantly to HSA, NEFA and AAG concentrations, with a particularly strong correlation with NEFA concentrations. Therefore, variation of HSA and NEFA concentrations in patients on maintenance therapy may cause an increase of tianeptine fu.
Adult↗