Different constraints on grip selection in brain-damaged patients: object use versus object transport

The present study discusses the presence of different constraints on action selection during object use versus object transport. Sixteen left brain-damaged (LBD) patients, 10 right brain-damaged (RBD) and 35 healthy controls were examined on a grip preference test consisting of a grasping-to-transport and a grasping-to-use condition. Assessment included a general praxis testing (pantomime production, object utilization gesture recognition and object use). We also reported the case of a close-head injury patient (DR) with an atypical behavioural pattern. Our results supported the different constraint hypothesis. While several LBD and RBD patients performed inappropriate grips in the grasping-to-transport condition, only two patients (L2 and DR) used inappropriate grips in the grasping-to-use condition. No correlation was found between the two conditions of the grip preference test and measures of the general praxis testing. The discussion focuses on the nature of constraints on grip selection during object use and object transport.

Object utilization and object usage: a single-case study

It has been suggested that both conceptual knowledge and the ability to infer function from structure can support object use. By contrast, we propose that object use requires solely the ability to reason about technical ends. Technical ends (e.g., cutting) are not purposes (e.g., eating), but the technical way to achieve them. This perspective suggests that there is no mutual relationship between technical ends and purposes since the same purpose (e.g., writing) can be achieved thanks to distinct technical ends (graving, tracing), and, inversely, the same technical end (e.g., tracing) can achieve different purposes (making up, writing). Thus, conceptual knowledge might determine which technical end is usually associated with a given purpose. To contribute to the discussion, we described the behaviour of a female patient with left temporal lobe lesions and bilateral frontal lobe lesions following a closed-head injury. Conceptual knowledge was impaired. She encountered difficulties in demonstrating the use of objects in isolation (e.g., using a screwdriver without the screw). The presence of a recipient (e.g., using a screwdriver with the screw) improved her performance. The performance was also normal when asked to perform unusual applications of objects to achieve a goal for which the usually applied object was not provided (e.g., screwing a screw with a knife). Consistent with the theoretical framework supported here, her performance profile suggests an intact ability to reason about technical ends (i.e., utilization), in the presence of a defective ability to determine the usual relationship between technical ends and purposes (i.e., usage).

Direct injection HPLC micro method for the determination of voriconazole in plasma using an internal surface reversed-phase column

A direct plasma injection liquid chromatographic method has been developed for the determination of a new triazole antifungal agent, voriconazole, using an internal surface reversed phase column. Therapeutic drug monitoring of voriconazole is relevant for patient management, especially in the case of drug-drug interaction. The method is easy to perform and requires 10 microL of a plasma sample. The chromatographic run time is less than 9 min using a mobile phase of 17:83 v/v acetonitrile-potassium dihydrogen phosphate buffer, 100 mM, pH 6.0 and UV detection at 255 nm. The fl ow rate was 1 microL/min. A linear response was observed over the concentration range 0.5-10 microg/mL (r2 = 0.977). A good accuracy (bias < or = 7.5%) was achieved for all quality controls, with intra-day and inter-day variation coefficients inferior to 6.7%. The lower limit of quantitation was 0.2 microg/mL, without interference of endogenous components. The stability of voriconazole in plasma stored at different temperatures was checked. Finally, the possibility of direct injection of plasma samples into the column permits a reduction in reagent consumption and in analytical steps, and hence in analytical error.

HPLC microdetermination offlurbiprofen enantiomers in plasma with a glycopeptide-type chiral stationary phase column

A rapid and stereospecific HPLC micromethod to quantify flurbiprofen enantiomers was developed. Both flurbiprofen enantiomers and indomethacin, used as internal standard, were extracted with methylene chloride from 100 microL of acidified plasma. The resolution of the R- and S-forms was performed on a bonded vancomycin chiral stationary phase (Chirobiotic V) with 20% of tetrahydrofuran in ammonium nitrate (100 mM, pH 5) as mobile phase. Calibration curves were linear in the range 0.5-10 microg/mL for both enantiomers. A good accuracy (< or = 5%) was obtained for all quality controls, with intra-day and inter-day variation coefficients equal or less than 7.7%. Recovery of both enantiomers was found in the range 77.4-86.3%. The lower limit of quantitation was 0.25 microg/mL for both enantiomers, without interference of endogenous components. This validated micromethod has been successfully applied for quantifying R- flurbiprofen and S- flurbiprofen in rat plasma.

Enantioselective synthesis of 2- and 3-substituted 2,3-dihydro[1,4]dioxino[2,3-b]pyridine derivatives and enantiomeric purity control by capillary electrophoresis

A rapid and simple procedure for enantioselective preparation of 2- and 3-substituted 2,3-dihydro[1,4]dioxino[2,3-b]pyridine derivatives (A and B, respectively) is described. The enantiomeric purity of each isomer was determined by capillary electrophoresis using a dual-cyclodextrin system (S-beta-CD/beta-CD) dissolved in formic acid-ammonia buffer (pH 4, ionic strength 50 mM).

Simultaneous determination of four antipsychotic drugs in plasma by high-performance liquid chromatography

A specific reversed phase-high pressure liquid chromatography (RP-HPLC) method has been developed for the simultaneous determination of clozapine (CZP), loxapine (LXP), zuclopenthixol (ZPT) and flupenthixol (FPT) in plasma. These four antipsychotic drugs are frequently used for the treatment of schizophrenia and other neuropsychiatric diseases. Carpipramine, a dihydrodibenzazepine, was used as an internal standard (I.S.). A liquid-liquid procedure was used to extract the drugs from human plasma. The analysis was performed on a XTerra MS C18 column with UV detection. Calibration curves were linear in the range 50-1000 microg/l. The limit of quantification (LOQ) was 15 microg/l for clozapine and loxapine and 20 microg/l for zuclopenthixol and flupenthixol. The coefficient of variation (CV) for intra- and inter-day precision was 7.2% or less with accuracies within 10% for the three concentrations.This isocratic and rapid method (run time<10 min) is useful for the management of acute intoxication.

Synthesis and anti-histaminic evaluation of N-phenyl-(alkyl)-5-(dialkylamino)methyl-2-amino-2-oxazolines

New N-phenyl(alkyl)-5-(dialkylamino)methyl-2-amino-2-oxazolines, 5a-e, have been synthesized from the corresponding 3-phenyl(alkyl)carbamoyl-2-iminooxazolidines 2. A two-stage hydrolysis reaction led finally to the corresponding ring-opened N-phenyl(alkyl)-N'-[1-(3-(dialkylamino)-propan-2-ol)]ureas 4. The oxazoline ring was regenerated through an intramolecular nucleophilic substitution involving an halogen atom introduced by the reaction of thionyl chloride on 4. Pharmacological properties of 5a-e were evaluated on histaminic and adrenergic receptors in guinea-pig trachea and rat aorta. Compounds 5b and 5e showed a selective anti-histaminic effect on guinea-pig airways, but a significant response was obtained for a concentration >10(-6) M. No pharmacological activity was obtained with oxazoline 5c whereas oxazolines 5a and 5d seemed to present a non-selective effect on the contractile mechanism of the smooth muscle cell.

Determination of pKa values of 2-amino-2-oxazolines by capillary electrophoresis

The dissociation constants of new 2-amino-2-oxazolines were determined by capillary electrophoresis (CE) as a new technique. A method based on a linear model has been used in the CE determination. A series of eight 2-amino-2-oxazolines are investigated to determine their ionization constant. Among them, three new oxazolines synthesized are presented. The Ka values were obtained from the plots of reciprocal effective mobility against inverse concentrations of protons. The potentiometric method (PM) was performed as a comparative method. No significant differences were observed between the determined dissociation constants using both methods. Thus, the pKa values have been found to vary between 8.55 and 8.68.

Rapid HPLC measurement of buflomedil in plasma in poisoning cases

A rapid high-performance liquid chromatographic method for the determination of buflomedil in human plasma is described. It requires a single liquid-liquid extraction step from 1 mL of plasma with diethyl ether followed by chromatography on a Nova Pak C(18) reversed-phase column and detection by ultaviolet light. Metoclopramide was used as internal standard. The method is sensitive with a quantification limit at 500 ng/mL. It was used for the determination of buflomedil in biological fluids in poisoning cases.

Determination of mirtazapine and its demethyl metabolite in plasma by high-performance liquid chromatography with ultraviolet detection. Application to management of acute intoxication

Mirtazapine is a new centrally acting noradrenergic and specific serotonin antidepressant, with an active demethyl metabolite. For toxicological purposes, a specific and accurate RP-HPLC assay was developed for the simultaneous plasma determination of these compounds. A linear response was observed over the concentration range 50-500 ng/ml. A good accuracy (bias <10%) was achieved for all quality controls, with intra-day and inter-day variation coefficients less than 8.3%. The lower limit of quantification was 20 ng/ml, without interferences with endogenous or exogenous components. This rapid method (run time <12 min) was used to manage three intoxications involving mirtazapine.

[Porphyria and drugs]

Porphyrias are the result of inherited enzymatic defects of the heme's biosynthesis chain. A porphyria crisis with abdominal pain and neurological or psychiatric signs may be precipitated by drugs. Our purpose is to list the main drugs which may precipitate phorphyria crisis, specifying which are contraindicated such as cefalosporins, anaesthetics, anti epileptic and anti tubercular drugs, and which are doubtful because of conflicting results published in literature. In any case it is necessary to verify any prescription before giving a drug to a patient with porphyria.

[Risk medications in case of glucose-6-phosphate dehydrogenase deficiency]

The best known morbid effect of glucosephosphate dehydrogenase (G-6PD) deficiency is hemolysis induced by oxidative drugs. When prescribing drugs for G-6PD deficient subjects, two points should be kept in mind: different genetic variants of G-6PD deficiency entail different susceptibility to the hemolytic risk from drugs; thus a drug found to be safe in some G-6PD deficient subjects may not be equally safe in others; the risk and severity of hemolysis is almost always dose-related. The purpose of this paper is to underline the main drugs that cannot be safely administrated to G-6PD deficient subjects. They can be separated in drugs that must be avoided by G-6PD deficient subjects (such as sulphonamides, quinolones, nitrofurantoin), and drugs that do not systematically precipitate hemolysis but must nevertheless be prescribed with caution.

Synthesis and preliminary behavioural evaluation in mice of new 3-aryl-3-pyrrol-1-ylpropanamides, analogues of FGIN-1-27 and FGIN-1-43

The 2-aryl-3-indoleacetamides FGIN-1-27 and FGIN-1-43 have already been characterized in-vitro as potent and specific ligands for the mitochondrial DBI receptor. This affinity was associated with psychotropic properties in several rodent behavioural tasks (in particular anxiolytic action) via enhancement of GABA transmission through neurosteroid production. The synthesis of new 3-aryl-3-pyrrol-1-ylpropanamides 1a-i, analogues of FGIN-1-27 and FGIN-1-43, is described in four steps starting from the corresponding arylaldehydes. Preliminary evaluation of these compounds in behavioural studies (spontaneous locomotor activity and anxiolytic activity) in mice was also undertaken.

Rapid high-performance liquid chromatographic measurement of venlafaxine and O-desmethylvenlafaxine in human plasma. Application to management of acute intoxications

Venlafaxine, a second-generation antidepressant, acts by inhibition of the reuptake of presynaptic noradrenaline and serotonin. The main metabolite, O-desmethylvenlafaxine was found biologically active. For toxicological purpose, a rapid specific and accurate RP-HPLC assay was developed for the simultaneous determination of venlafaxine and O-desmethylvenlafaxine in human plasma. A linear response was observed over the concentration range 0.2-4 microg/ml. A good accuracy (<8%) was achieved for all quality controls, with intra-day and inter-day variation coefficient less than 10%. Finally, no interference was observed with other psychotic drugs encountered in acute poisoning. This rapid method (run time <10 min) was used to manage four voluntary intoxications involving venlafaxine.

Synthesis and pharmacological evaluation of 5-dialkylaminomethyl-2-amino-2-oxazolines as H1-antagonists

New 5-dialkylaminomethyl-2-amino-2-oxazolines have been synthezised in two steps from the corresponding dialkylamines. They were evaluated in-vitro as H1-antagonists. Compounds 1c, 1d and 1j significantly antagonized histamine-induced contraction of guinea-pig trachea with a rightward shift of the concentration-response curve to histamine. Compound 1f, 5-[(4-benzyl-1-piperidinyl)methyl]-2-amino-2-oxazoline, induced an increase in acetylcholine Emax (the maximal response to acetylcholine 10(-3) M) and a shift to the left of the concentration-response curve. The lack of effect of this compound on histamine-induced contraction rules out a non-selective potentiation of the contraction mechanisms. Preliminary structure-activity results were reported partly based on physicochemical results.