Solid-phase extraction of 1,4-benzodiazepines from biological fluids

The solid-phase extraction (SPE) of seven 1,4-benzodiazepines (oxazepam, diazepam, temazepam, nordazepam, brotizolam, adinazolam and midazolam) using prazepam as internal standard was investigated. The 1,4-benzodiazepines were recovered from an aqueous buffer of suitable pH, using C18 Sep-Pak cartridges and mixtures of methanol-water as elution solvent. The recovery of oxazepam using different sorbent materials (C2, C8, C18, cyanopropyl, phenyl and cyclohexyl Bond-Elut) was also examined as a function of pH and the composition of the elution solvent. The SPE of oxazepam was investigated using spiked urine samples and the C2 cartridge gave rise to the cleanest urine extracts. The recoveries of the other 1,4-benzodiazepines from spiked urine and plasma samples using the C2 cartridge was then found to be higher than 90%, without any interference from endogenous compounds of the samples. Finally, the influence of other factors such as drug concentration, sample volume and the number of times the SPE cartridge had been used was also examined.

Multi-centre double-blind trial on the efficacy and safety of sertaconazole 2% cream in comparison with miconazole 2% cream on patients suffering from cutaneous mycoses

The efficacy and tolerance of 7-chloro-3-[1-(2,4-dichlorophenyl)-2- (1H-imidazol-1-yl)ethoxy-methyl]benzo[b]thiophene (sertaconazole, FI-7045, CAS 99592-32-2) 2% dermatological cream in two daily applications compared with miconazole 2% cream in two daily applications were studied on 631 patients suffering from superficial cutaneous mycosis (sertaconazole n = 317, miconazole n = 314), in a double-blind, controlled multicentre trial with parallel groups. The therapeutic efficacy was evaluated by clinical assessment of the improvement of the lesion and symptoms, a microscopic test on the presence of hyphae or mycelia in the affected area and a culture test on the presence of active infection. Tolerance and safety were evaluated by a general blood analysis and interrogation of the patient on adverse effects. The rate of clinical cures for both treatments at the end of the follow-up was 95.6% for sertaconazole and 88.1% for miconazole, with the difference being statistically significant. In the comparative analysis of the actuarial curve, it was observed that the patients treated with sertaconazole were cured earlier and in a higher proportion than those treated with miconazole, with the difference being significant. The negative result of the microscope examination and culture test confirmed the superiority of sertaconazole over miconazole, already after 14 days of treatment. At the end of the follow-up, 98.6% of the patients in the sertaconazole group obtained a negative culture test result, as opposed to 91.7% in the miconazole group, with the difference being highly significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Findings on Doppler echocardiography in asymptomatic intravenous heroin users

To detect potential cardiac abnormalities induced by intravenous heroin use, 68 persons without a previous episode of infective endocarditis were studied by Doppler echocardiography. A control group of 41 normal subjects was studied for comparison. The following measurements were considered: (1) diameter of heart chambers, (2) systolic left ventricular function, (3) morphologic valvular abnormalities, (4) presence of valve regurgitations, (5) Doppler indexes of diastolic function, and (6) estimation of pulmonary arterial resistances. Results showed no significant differences regarding the size of the heart chambers or systolic left ventricular function. A significantly higher incidence of valvular abnormalities (focal thickening or valve prolapse) was found in drug addicts (p = 0.0009) at the mitral and tricuspid valves, as was valvular regurgitation detected by Doppler (p = 0.04). Also, a significantly prolonged deceleration time of mitral and tricuspid early diastolic Doppler flow was found in the study group (p = 0.0001 and 0.027, respectively) although a different hemodynamic condition in the study group (pharmacologically reduced preload) precluded these findings to be attributable to an actual diastolic dysfunction. No differences were observed in pulmonary arterial resistances. It is concluded that mitral and tricuspid valve abnormalities can be detected by echocardiography in asymptomatic intravenous heroin users, whereas no apparent effects are observed in morphologic or functional parameters of cardiac structures other than the valves.

Issues for comparability of DRG statistics in Europe. Results from EURODRG

DRG use has spread through most European countries thus offering an opportunity for improving hospital data bases at the European level. An EEC Concerted Action 'Use of DRGs to support Hospital Sector Management in the European Community' was approved by the Committee of Health Services Research of the EEC. A general overview of the project is presented as well as a detailed description of the results of the work on aspects related to DRG data production. These aspects (MBDS implementation and variables definition; coding systems and updating; mapping systems; data auditing; trimming methods; and DRG grouper versions) have been analyzed with the objective of increasing opportunities for valid international comparisons of DRG statistics between European countries.

The development of cost information by DRG--experience in a Barcelona hospital

The determination of hospital patient costing adjusted by case-mix is one of the possible applications arising from the emergence of patient classification systems, such as Diagnosis Related Groups (DRGs). Most of the experiences up until now have given priority to the determination of the total costs by DRG, making it difficult to establish comparisons between hospitals. In this article, results of an experience in Barcelona with a direct patient costing model are presented, with these later being grouped into DRGs. Descriptive information is given together with statistical analysis of the intra-DRG variability and the relationship between costs and the length of stay. Patient costing systems represent a useful instrument for hospital management as they allow analyzing variation and its reasons at DRG level. It is in fact the primary level of information required in order to develop management control in hospitals.

Postsynaptic dopamine/adenosine interaction: II. Postsynaptic dopamine agonism and adenosine antagonism of methylxanthines in short-term reserpinized mice

Caffeine and its first-stage metabolites (paraxanthine, theophylline and theobromine) caused a significant potentiation of the locomotor activity induced by bromocriptine, 5 mg/kg, in mice pretreated with reserpine, 5 mg/kg (4h prior to the start of motor activity recordings). None of these substances significantly enhanced locomotor activity in reserpinized mice when administered alone. The rank order of potency was caffeine greater than paraxanthine greater than theophylline greater than theobromine. A high dose of a D-2 antagonist (sulpiride 100 mg/kg) caused a marked inhibition of the locomotor activity induced by bromocriptine, 5 mg/kg, plus 25 mg/kg of caffeine, paraxanthine or theophylline. However, a high dose of a D-1 antagonist (SCH-23390 1 mg/kg) caused a significant decrease of the locomotor activity induced by bromocriptine 5 mg/kg, plus 25 mg/kg of caffeine or paraxanthine, but did not change the locomotor activity caused by bromocriptine, 5 mg/kg, plus theophylline 25 mg/kg. The inhibitory effect of 5'-(N-ethyl)carboxamido-adenosine (NECA), 0.025 mg/kg, on bromocriptine-induced locomotor activation in reserpinized mice was reversed by the simultaneous administration of 10, 25 and 50 mg/kg of caffeine, paraxanthine or theophylline. The rank order of potency for reversal was theophylline greater than paraxanthine = caffeine. We suggest that methylxanthines act postsynaptically by potentiating the effects of D-2 stimulation and that this potentiation can be produced by D-1 agonism (paraxanthine or caffeine) and by adenosine antagonism (theophylline, paraxanthine or caffeine), most probably involving A-2 receptors.

Postsynaptic dopamine/adenosine interaction: I. Adenosine analogues inhibit dopamine D2-mediated behaviour in short-term reserpinized mice

Mice pretreated with reserpine 5 mg/kg (4 h prior to the start of motor activity recording) showed locomotor activation after the administration of the D-2 agonist bromocriptine (5 mg/kg). This bromocriptine-induced locomotor activity was dose dependently inhibited by the co-administration of a D-2 antagonist (sulpiride) and dose dependently potentiated by a D-1 agonist (CY 208-243). The potentiating effect of the D-1 agonist could be inhibited by either a D-1 or a D-2 antagonist (SCH 23390 1 mg/kg or sulpiride 100 mg/kg, respectively). The bromocriptine-induced locomotor activity was not altered by either blockade of D-1 dopaminergic receptors (SCH 23390 1 mg/kg) or by co-administration of a greater dose of reserpine (10 mg/kg) plus the dopamine synthesis inhibitor, alpha-methyl-p-tyrosine (200 mg/kg). The adenosine agonists, L-PIA (a preferentially A-1 adenosine agonist) and NECA (an A-1 and A-2 adenosine agonist with above 10-fold greater affinity for A-2 than L-PIA) inhibited in a dose-dependent manner the effect of bromocriptine, NECA being above ten times more potent than L-PIA. The findings show that bromocriptine stimulates postsynaptic D-2 receptors in dopamine-depleted mice and that this effect can be inhibited by adenosine stimulation. The existence of a postsynaptic D-2/A-2 interaction is suggested, the stimulation of A-2 receptors causing an inhibition of responses elicited by postsynaptic D-2 stimulation.

Paraxanthine displaces the binding of [3H]SCH 23390 from rat striatal membranes

We present evidence showing that paraxanthine (1,7-dimethylxanthine), the main metabolite of caffeine in man, displaces the binding of [3H]SCH 23390, a radioligand which selectively labels dopamine D-1 receptors when used at low concentrations, from striatal membranes of the rat. The displacement was competitive and indicated the existence of two affinity states (Hill coefficient = 0.49; K(high) = 0.15 microM; K(low) = 95.9 microM, %R(high) = 32.4). When the stable GTP analog Gpp(NH)p was included, the displacement curve indicated the presence of only the low-affinity state (Hill coefficient = 1.16; Ki = 72.1 microM). However, paraxanthine did not displace the specific binding of [3H]spiperone. After injection of 30 mg/kg s.c. of caffeine, a maximum of 10 microM of paraxanthine was found in striatal homogenates, which could be sufficient to occupy dopamine D-1 receptors. Our results suggest that a dopaminergic action of paraxanthine could be involved in the behavioural stimulation produced by caffeine.

Is experimental catalepsy properly measured?

Following logarithmic transformation (ln) of total duration of haloperidol-induced catalepsy in the rat, measured by means of the bar test, a normalization of the results is achieved. With the help of this transformation we have been able to study what are probably the most important variables involved in the measuring of experimental catalepsy and to establish some criteria for a better use of such measures: 1) repeated measures of catalepsy have to be taken in order to avoid the stress-induced inhibition of catalepsy caused by the new experimental situation, 2) the dose of neuroleptic used has to be sufficiently low to permit the measurement of total or real duration of catalepsy between two determinations, and 3) the dose of neuroleptic has to be sufficiently high to prevent the development of a learned "pseudocatalepsy."

T-maze performance in rats following chronic neuroleptic treatment

The effects of chronic haloperidol treatment (0.5 mg/kg/day for 21 days) on maze learning in the rat were studied. There were no differences between haloperidol- and saline-treated groups in percentage of correct responses, but the latency to respond was longer and extinction was faster in the haloperidol-treated group. We speculated that differences between both groups were due to a decrease of appetitive motivation in haloperidol-treated animals, probably caused by a decrease of dopaminergic neurotransmission.

BHT-920 and LY-171555 (quinpirole) have similar affinities for striatal D-2 dopamine receptors, and similar affinities for striatal D-1 dopamine receptors

The affinity of LY-171555 (quinpirole) and BHT-920 for both states of rat striatal dopamine D-1 and D-2 receptors was determined. Although these drugs have different pharmacological effects in experimental animals, we found that they had similar affinities for both D-1 and D-2 receptors.

Rotational behaviour induced by theophylline in 6-OHDA nigrostriatal denervated rats is dependent on the supersensitivity of striatal dopaminergic receptors

We studied apomorphine- and theophylline-induced rotational behaviour in rats with a unilateral 6-hydroxydopamine lesion of the dopaminergic nigrostriatal pathway. It was seen that there was a direct correlation between the number of apomorphine- and theophylline-induced contralateral turns. These data suggest the existence of a relationship between theophylline-induced rotational behaviour and the degree of supersensitivity of the striatal dopaminergic receptors. Because the rotational behaviour induced by theophylline is in the same direction as dopaminergic agonists, contralateral to the nigrostriatal pathway lesion, these results suggest the possibility of a direct dopaminergic agonism of methylxanthines.

Relationship between rotational behaviour induced by apomorphine and caffeine in rats with unilateral lesion of the nigrostriatal pathway

The contralateral rotational behaviour produced by apomorphine and caffeine has been studied in 100 rats with unilateral lesion of the nigrostriatal pathway induced with 6-OHDA. Rats with a two-peak rotational pattern induced by apomorphine, showed a greater number of contralateral turns, induced by apomorphine and caffeine, than rats which did not show this rotational pattern. A correlation was observed between the number of rotations induced by apomorphine and those induced by caffeine. A relationship between the two-peak rotational pattern induced by apomorphine and the initial-peak pattern induced by caffeine was also observed.

Conditioning of rotational behavior after the administration of a single dose of apomorphine in rats with unilateral denervation of the dopaminergic nigrostriatal pathway: relevance to drug addiction

Our aim is to study the relationship of drug activation of the dopamine neurotransmission system and the conditioning of environmental stimuli present at the time of drug administration. We injected a single dose of apomorphine (0.05 mg/kg SC) in rats with the nigrostriatal dopamine pathways unilaterally denervated with 6-hydroxydopamine, which generates rotational behavior contralateral to the lesioned hemisphere. We observed rotational behavior without apomorphine administration when animals were reexposed at different time intervals to the same environment in which they performed turning behavior. The present findings show that this rotational behavior can be conditioned to environmental stimuli in a strong and long-lasting way. In light of the relationship between opioids and the dopaminergic system, similar conditioning could take place in the learning processes implicated in drug addiction.