Transanal irrigation is a better choice for bowel dysfunction in adults with Spina bifida: A randomised controlled trial

AIM

To compare transanal irrigation with conservative bowel management for the treatment of bowel dysfunction in Spina bifida (SB) patients.

METHODS

Patients with SB and bowel dysfunction were randomly assigned to receive either transanal irrigation or conservative bowel management. The effectiveness of the treatment was defined as a decrease of 4 points in the neurogenic bowel dysfunction (NBD) score at week 10. Data on incontinence (Cleveland scores; Jorge-Wexner [JW]) and constipation (Knowles-Eccersley-Scott Symptom Constipation Score [KESS]) were recorded at 10 and 24 weeks after inclusion. Data were analysed on an intention-to-treat basis.

RESULTS

A total of 34 patients were randomised: 16 patients to conservative bowel management and 18 patients to transanal irrigation. A total of 19/31 (61%) patients improved at week 10, 13 (76%) in the transanal irrigation group versus six (43%) in the conservative group (p = 0.056). In the irrigation group, the decrease in NBD score was -6.9 (-9.9 to -4.02) versus -1.9 (-6.5 to -2.8) in the conservative group (p = 0.049 in univariate and p = 0.004 in multivariate analysis). The NBD, Cleveland (JW and KESS) and Rosenberg scores were significantly lower in the transanal irrigation group than in the conservative bowel management group at week 10.

CONCLUSIONS

This prospective, randomised, controlled, multicentre study in adult patients with SB suggests that transanal irrigation may be more effective than conservative bowel management.

Risks and Benefits of Nalmefene in the Treatment of Adult Alcohol Dependence: A Systematic Literature Review and Meta-Analysis of Published and Unpublished Double-Blind Randomized Controlled Trials

BACKGROUND

Nalmefene is a recent option in alcohol dependence treatment. Its approval was controversial. We conducted a systematic review and meta-analysis of the aggregated data (registered as PROSPERO 2014:CRD42014014853) to compare the harm/benefit of nalmefene versus placebo or active comparator in this indication.

METHODS AND FINDINGS

Three reviewers searched for published and unpublished studies in Medline, the Cochrane Library, Embase, ClinicalTrials.gov, Current Controlled Trials, and bibliographies and by mailing pharmaceutical companies, the European Medicines Agency (EMA), and the US Food and Drug Administration. Double-blind randomized clinical trials evaluating nalmefene to treat adult alcohol dependence, irrespective of the comparator, were included if they reported (1) health outcomes (mortality, accidents/injuries, quality of life, somatic complications), (2) alcohol consumption outcomes, (3) biological outcomes, or (4) treatment safety outcomes, at 6 mo and/or 1 y. Three authors independently screened the titles and abstracts of the trials identified. Relevant trials were evaluated in full text. The reviewers independently assessed the included trials for methodological quality using the Cochrane Collaboration tool for assessing risk of bias. On the basis of the I2 index or the Cochrane's Q test, fixed or random effect models were used to estimate risk ratios (RRs), mean differences (MDs), or standardized mean differences (SMDs) with 95% CIs. In sensitivity analyses, outcomes for participants who were lost to follow-up were included using baseline observation carried forward (BOCF); for binary measures, patients lost to follow-up were considered equal to failures (i.e., non-assessed patients were recorded as not having responded in both groups). Five randomized controlled trials (RCTs) versus placebo, with a total of 2,567 randomized participants, were included in the main analysis. None of these studies was performed in the specific population defined by the EMA approval of nalmefene, i.e., adults with alcohol dependence who consume more than 60 g of alcohol per day (for men) or more than 40 g per day (for women). No RCT compared nalmefene with another medication. Mortality at 6 mo (RR = 0.39, 95% CI [0.08; 2.01]) and 1 y (RR = 0.98, 95% CI [0.04; 23.95]) and quality of life at 6 mo (SF-36 physical component summary score: MD = 0.85, 95% CI [-0.32; 2.01]; SF-36 mental component summary score: MD = 1.01, 95% CI [-1.33; 3.34]) were not different across groups. Other health outcomes were not reported. Differences were encountered for alcohol consumption outcomes such as monthly number of heavy drinking days at 6 mo (MD = -1.65, 95% CI [-2.41; -0.89]) and at 1 y (MD = -1.60, 95% CI [-2.85; -0.35]) and total alcohol consumption at 6 mo (SMD = -0.20, 95% CI [-0.30; -0.10]). An attrition bias could not be excluded, with more withdrawals for nalmefene than for placebo, including more withdrawals for safety reasons at both 6 mo (RR = 3.65, 95% CI [2.02; 6.63]) and 1 y (RR = 7.01, 95% CI [1.72; 28.63]). Sensitivity analyses showed no differences for alcohol consumption outcomes between nalmefene and placebo, but the weight of these results should not be overestimated, as the BOCF approach to managing withdrawals was used.

CONCLUSIONS

The value of nalmefene for treatment of alcohol addiction is not established. At best, nalmefene has limited efficacy in reducing alcohol consumption.

The fallacy of thresholds used in defining response and remission in depression rating scales

Response and remission are determined by the proportion of people who fall below a threshold score on depression rating scales. This calculation implies a possibility of false positives (FP) and false negatives (FN) depending on sensitivity and specificity of the threshold used, but also on response and remission rates. A simulation illustrates the methodological consequences of this phenomenon in a comparative trial where response and remission rates differ between groups: the probability of being misclassified differs between groups, and measures of association (relative risk and odds ratio) are biased. Alternatives are proposed to cope with this misclassification bias.

Limbic versus cognitive target for deep brain stimulation in treatment-resistant depression: accumbens more promising than caudate

High-frequency deep brain stimulation (DBS) represents a major stake for treatment for treatment-resistant depression (TRD). We describe a preliminary trial of DBS of two potential brain targets in chronic TRD: the nucleus accumbens (Acb) and, in the event of failure, the caudate nucleus. Patients were followed for 6 months before surgery (M0). From M1 to M5, they underwent stimulation of the Acb target. PET scans allowed us to track metabolic modifications resulting from this stimulation. The caudate target of nonresponders was stimulated between M5 and M9. Patients then entered an extension phase, in which it was possible to adapt stimulation parameters and treatments. Six patients were included and four were operated on. At M5, none of the patients were either responders or remitters, but we did observe a decrease in Hamilton Depression Rating Scale (HDRS) scores. Three patients were switched to caudate stimulation, but no improvement was observed. During the extension phase, the Acb target was stimulated for all patients, three of whom exhibited a significant response. A decrease in glucose metabolism was observed after Acb stimulation, in the posterior cingulate gyrus, left frontal lobe, superior and medial gyrus, and bilateral cerebellum. An increase in metabolism was observed in the bilateral frontal lobe (superior gyrus), left frontal lobe (medial gyrus), and right limbic lobe (anterior cingulate gyrus). The results of this trial suggest that Acb is a more promising target than the caudate. NCT01569711.

Cranberry versus placebo in the prevention of urinary infections in multiple sclerosis: a multicenter, randomized, placebo-controlled, double-blind trial

Objective:

Our aim was to assess the usefulness of cranberry extract in multiple sclerosis (MS) patients suffering from urinary disorders.

Methods:

In total, 171 adult MS outpatients with urinary disorders presenting at eight centers were randomized (stratification according to center and use of clean intermittent self-catheterization) to cranberry versus placebo in a 1-year, prospective, double-blind study that was analyzed using a sequential method on an intent-to-treat basis. An independent monitoring board analyzed the results of the analyses each time 40 patients were assessed on the main endpoint. Cranberry extract (36 mg proanthocyanidins per day) or a matching placebo was taken by participants twice daily for 1 year. The primary endpoint was the time to first symptomatic urinary tract infection (UTI), subject to validation by a validation committee.

Results:

The second sequential analyses allowed us to accept the null hypothesis (no difference between cranberry and placebo). There was no difference in time to first symptomatic UTI distribution across 1 year, with an estimated hazard ratio of 0.99, 95% CI [0.61, 1.60] ( p = 0.97). Secondary endpoints and tolerance did not differ between groups.

Conclusion:

Taking cranberry extract versus placebo twice a day did not prevent UTI occurrence in MS patients with urinary disorders. Trial Registration NCT00280592.

Which placebo to cure depression? A thought-provoking network meta-analysis

BACKGROUND

Antidepressants are often considered to be mere placebos despite the fact that meta-analyses are able to rank them. It follows that it should also be possible to rank different placebos, which are all made of sucrose. To explore this issue, which is rather more epistemological than clinical, we designed an unusual meta-analysis to investigate whether the effects of placebo in one situation are different from the effects of placebo in another situation.

METHODS

Published and unpublished studies were searched for by three reviewers on Medline, the Cochrane Library, Embase, clinicaltrials.gov, Current Controlled Trial, in bibliographies, and by mailing key organizations. The following studies in first-line treatment for major depressive disorder were considered to construct an "evidence network": 1) randomized controlled trials (RCTs) versus placebo on fluoxetine, venlafaxine and 2) fluoxetine versus venlafaxine head-to-head RCTs.Two network meta-analyses were run to indirectly compare response and remission rates among three different placebos: 1) fluoxetine placebo, 2) venlafaxine placebo, and 3) venlafaxine/fluoxetine placebo (that is, placebo compared to both venlafaxine and fluoxetine). Publication biases were assessed using funnel plots and statistically tested.

RESULTS

The three placebos were not significantly different in terms of response or remission. The antidepressant agents were significantly more efficacious than the placebos, and venlafaxine was more efficacious than fluoxetine. The funnel plots, however, showed a major publication bias.

CONCLUSION

The presence of significant levels of publication bias indicates that we cannot even be certain of the conclusion that sucrose equals sucrose in trials of major depressive disorder. This result should remind clinicians to step back to take a more objective view when interpreting a scientific result. It is of crucial importance for their practice, far more so than ranking antidepressant efficacy.

Improving study design for antidepressant effectiveness assessment

Antidepressants effectiveness in major depressive disorder (MDD) is still questioned because the extrapolation of randomized controlled trial (RCT) results to "real life" settings is problematic. The application of the RCT paradigm in a disorder of this type, where global care plays a central role, raises questions regarding the internal and external validity of this type of study. Outcome measurement, attrition rates, the ability of the double-blind design to control for expectations, placebo response, the representativeness of trial participants and publication bias are major methodological pitfalls. This review discusses these issues. It is illustrated using original data and proposes some alternatives for assessing antidepressant effectiveness via different approaches. Some are easy to implement, such as ecological measures, qualitative approaches, improvement of analytical strategy and improvement of blinding procedures. Some are sophisticated, involving temporary deception to deal with the confounding effect of expectations, and they raise ethical issues. Others resort to external validity, this being the case in observational studies. But all are necessary to explore antidepressant effectiveness.

Effects of phlebotomy therapy on cytochrome P450 2e1 activity and oxidative stress markers in dysmetabolic iron overload syndrome: a randomized trial

AIM

To assess the effects of iron removal on cytochrome P450 2E1 activity and oxidative stress in dysmetabolic iron overload syndrome.

METHODS

Forty-eight patients were randomized to phlebotomy therapy consisting of removal of 300-500 mL of blood every 14 days until serum ferritin levels dropped under 100 microg/L or to follow-up without phlebotomy therapy. Cytochrome P450 2E1 activity was measured at baseline and at the end of treatment by using the 6-hydroxychlorzoxazone/chlorzoxazone blood metabolic ratio, 2 h after the intake of 500 mg of chlorzoxazone.

RESULTS

In the treatment group, a mean of 3.9 +/- 1.3 L of blood was removed and serum ferritin levels dropped from 715 +/- 397 to 74 +/- 34 microg/L. Variation of cytochrome P450 2E1 activity was not significantly different between the 2 groups (0.07 +/- 0.26 vs. 0.03 +/- 0.19, P = 0.36). In the treatment group, low-density lipoprotein cholesterol and vitamin E were lowered after treatment compared with control group (-0.15 +/- 0.51 vs. 0.24 +/- 0.58, P = 0.002 and -1.3 +/- 4.4 vs. 2.3 +/- 5.2, P = 0.03, respectively). Inversely, vitamin C was increased (0.5 +/- 3.5 vs. -1.8 +/- 3.9, P = 0.03).

CONCLUSIONS

In dysmetabolic iron overload syndrome, reduction of iron stores does not significantly influence cytochrome P450 2E1 activity but is associated with a significant decrease of low-density lipoprotein cholesterol, suggesting that venesection therapy may be a suitable option in these patients.

Does subthalamic nucleus stimulation induce apathy in Parkinson's disease?

BACKGROUND

Subthalamic Nucleus Deep Brain Stimulation (STN-DBS) has been shown to significantly improve motor symptoms in advanced Parkinson's disease (PD). Only few studies, however, have focused on the non-motor effects of DBS.

METHODS

A consecutive series of 15 patients was assessed three months before (M-3), then three months (M3) and six months (M6) after surgery. Mean (+/- SD) age at surgery was 59.7 (7.6). Mean disease duration at surgery was 12.2 (2.8) years. The Mini International Neuropsychiatric Inventory was used to assess psychiatric disorders three months before surgery. Depression was evaluated using Montgomery and Asberg Rating Scale (MADRS). Anxiety was evaluated using the AMDP system (Association for Methodology and Documentation in Psychiatry). Apathy was particularly evaluated using the Apathy Evaluation Scale (AES) and the Starkstein Scale. All these scales were performed at every evaluation.

RESULTS

Apathy worsened at M3 and M6 after STN-DBS in comparison with the preoperative evaluation: the AES mean score was significantly impaired between the preoperative (38.4+/-7.1) and both the postoperative M3 (44.6+/-9.5, p = 0.003) and M6 scores (46.0+/-10.9, p = 0.013). Significant worsening of apathy was confirmed using the Starkstein scale. There was no evidence of depression: the mean MADRS score did not differ before surgery (9.1+/-7.4) and at both M3 (8.6+/-8.2) and M6 (9.9+/-7.7) after STN-DBS. The anxiety level did not change between preoperative (9.4+/-9.2) and both M3 (5.5+/-4.5) and M6 (6.6+/-4.6) postoperative states.

CONCLUSION

Although STN-DBS constitutes a therapeutic advance for severely disabled patients with Parkinson's disease, we should keep in mind that this surgical procedure may contribute to the inducing of apathy. Our observation raises the issue of the direct influence of STN- DBS on the limbic system by diffusion of stimulus to the medial limbic compartment of STN.

Differential effects of two types of antidepressants, amitriptyline and fluoxetine, on anorectal motility and visceral perception

BACKGROUND

Although antidepressants are used for functional gastrointestinal disorders, the mechanisms of their effects on gut are incompletely understood.

AIM

To assess the effects of two types of antidepressants (tricyclic, serotoninergic) on anorectal motility and visceral perception.

METHODS

A placebo-controlled, randomized, double-blind, crossover study was performed in 12 healthy male volunteers who received a single oral dose of amitriptyline (80 mg), fluoxetine (40 mg) or placebo. Drug effects were assessed using phasic isobaric distensions of the rectum with an electronic barostat (11 levels from 1 to 51 mmHg) 4 h after drug intake. Maximal rectal volume and pressure, mean and residual pressures at upper anal canal, mean pressure at lower anal canal, defecation sensation (5-level scale) and visceral perception (visual analogue scale) were recorded at each level of distending pressure.

RESULTS

Ten subjects completed the study. Compared with placebo, neither amitriptyline nor fluoxetine modified rectal compliance or visceral perception. Compared with placebo, antidepressants significantly reduced mean and residual pressures at upper anal canal (-18%, P = 0.0019, and -27%, P = 0.0002, respectively, for amitriptyline; -26%, P = 0.0001, and -33%, P = 0.0001, respectively, for fluoxetine) whereas only amitriptyline significantly reduced mean pressure at lower anal canal (-16%, P = 0.0008).

CONCLUSION

Both antidepressants similarly relaxed the internal anal sphincter, probably through a non-specific mechanism, without modifying visceral perception. Only amitriptyline relaxed the external anal sphincter.

[Perspectives for drug treatment in Alzheimer's disease]

The last decade was very fruitful in neuropharmacology and notably in the therapeutic strategies of dementia and Alzheimer's disease (AD). The amount of data, information and breakthroughs is nevertheless difficult to apply in direct relationship with patients. The present review aims at classifying information according to their origins: epidemiology, clinical trials, neurosciences. A guide for drug prescription in Alzheimer's disease is thus warranted and becomes clearer, sure that, in the next future modifications and new strategies will appear. The main goal of the present review is to summarize the state-of-the-art for a non specialist in AD.

Role of dopaminergic and serotonergic systems on behavioral stimulatory effects of low-dose alprazolam and lorazepam

Several recent studies have demonstrated that alprazolam and lorazepam, administered at low doses to healthy volunteers, improve cognitive functions and psychomotor performances. Paradoxical effects of low-dose benzodiazepines have been also observed in mice, in experimental pharmacology. The aim of this work was to determine, in rat, the effect of similar low-doses of benzodiazepines on spontaneous locomotor activity and performance in the elevated zero-maze, and to investigate the underlying neurobiological mechanisms. The dose-effect and the time-course of the action were studied for both compounds. Spontaneous locomotor activity was measured using a photoelectric actimeter. The level of anxiety of the animals was assessed in the elevated zero-maze. Dopamine, serotonin, and their metabolites were assayed in the extracellular striatal fluid of the awake rat, obtained by microdialysis, by HPLC--EC. Spontaneous locomotor activity observed in rats given low-dose alprazolam and lorazepam evidenced a stimulatory effect only with alprazolam. The effect was maximum 90 min after administration of 0.0050 mg/kg alprazolam. An anxiogenic-like action was evidenced with the elevated zero-maze for the two compounds. We observed a statistically significant increase in striatal dopamine concentrations only with alprazolam, during the period corresponding to the behavioral stimulatory effects. We also showed a marked trend towards increased levels of serotonin with alprazolam but this modification was not significant, in spite of statistically significant variations of 5-HIAA. In the rat, behavioral stimulatory effects of low-dose benzodiazepines is evidenced with alprazolam but not lorazepam. This effect could be explained, at least in part, by increased extracellular dopamine concentrations in the striatum. Their different structures could explain the different pattern observed for the two benzodiazepines.

Procedural memory in recent-onset Parkinson's disease

Parkinson's disease is accompanied by cognitive disorders which may affect procedural memory. Procedural memory uses a specific knowledge resource that expresses itself through pre-established acting procedures. The aim of this study was to better define the characteristics of procedural memory, first of all, by trying to determine the level of involvement of that memory in the acquisition process (during learning and/or during procedure maintenance), then by specifying the effect of the type of resource involved (verbal or motor). To achieve this, we compared the mnestic performances of 20 recent-onset parkinsonian patients with those of 20 healthy controls, using two memory tasks with a fixed rule (poetry, visuomotor tracking). Result analysis revealed that parkinsonian patients had more difficulty than controls in learning the two rules, regardless of the material involved. Their deficiencies were often associated with an impairment of executive functions, and the procedural memory problems described in parkinsonian patients are linked to the involvement of these resources in the various tasks.

5-HT-moduline, a 5-HT(1B/1D) receptor endogenous modulator, interacts with dopamine release measured in vivo by microdialysis

5-Hydroxytryptamine-moduline (5-HT-moduline) is an endogenous tetrapeptide (Leu-Ser-Ala-Leu) recently isolated and characterized from mammalian brain. This compound interacts with 5-HT1B receptors as a non-competitive, high-affinity antagonist and has the properties of an allosteric modulator. 5-HT-moduline could play an important role in the regulation of serotonergic transmission and also, through heteroreceptors, dopaminergic transmission. The aim of this work was to examine the potential ability of 5-HT-moduline to modify the basal extracellular concentration of dopamine and its metabolites (3-methoxytyramine, dihydroxyphenylacetic acid and homovanillic acid), in the rat striatum and to determine its potential interaction with the stimulating activity of a specific 5-HT1B receptor agonist, 3-(1,2,5,6-tetrahydropyrid-4-yl) pyrrolo [3,2-b] pyrid-5-one (CP-93,129), on the release of dopamine. The technique is based on in vivo microdialysis using probes implanted in the striatum of the conscious rat. Results showed that the perfusion of 5-HT-moduline directly into this structure (1.25 mM) increased the striatal level of dopamine by two-fold (104% of the absolute basal release values, P = 0.0015) and that of 3-methoxytyramine by 3-fold (293%, P = 0.0001) without any change in the terminal metabolite concentrations. The intrastriatal administration of CP-93,129 induced a statistically significant, dose-dependent increase of dopamine levels (P < 0.0001). Coperfusion of 5-HT-moduline did not significantly alter the effect of CP-93,129 at 0.1 and 0.5 mM, but appeared to have an additive effect on the lowest dose (P = 0.0406). The results obtained show that 5-HT-moduline directly administered into the striatum increases the release of dopamine in this area. Presumably, this effect results from the desensitization of 5-HT1B receptors located on dopamine terminals. However, the fact that a 5-HT1B receptor agonist (CP-93,129) also increased the release of dopamine in the striatum and that 5-HT-moduline exhibited a slight additive effect with that of a low concentration of CP-93,129 suggests that the two substances interact with different mechanisms.

Dopamine D2 receptor agonists protect against ischaemia-induced hippocampal neurodegeneration in global cerebral ischaemia

To characterise the role played by dopamine receptors in ischaemic brain damage, we have evaluated the effects of pergolide, bromocriptine and lisuride (dopamine D2 receptor agonists), haloperidol (a dopamine D2 receptor antagonist), 2,3,4,5-tetrahydro-7,8,dihydroxy-1-phenyl-1H-3-benzazepine (SKF 38393; a dopamine D1 receptor agonist) and (R)-(+)-8-chloro 2,3,4,5-tetra-hydro-3-methyl-5-phenyl-1H-3-benzazepin-7-ol (SCH 23390; a dopamine D1 receptor antagonist) in the gerbil model of global cerebral ischaemia. Ischaemia was induced by 5 min of bilateral carotid artery occlusion under halothane anaesthesia. Sham operated animals were used as controls. Pergolide (0.5 or 1.0 mg/kg i.p), bromocriptine (0.5 or 1.0 mg/kg i.p.), lisuride (0.5 or 1.0 mg/kg i.p.), SCH 23390 (0.1 or 1.0 mg/kg i.p.), haloperidol (0.5, 1.0 or 2 mg/kg i.p.) and SKF 38393 (1.0 or 2 mg/kg i.p.) were administered 1 h before occlusion. Five-minute-occluded animals had extensive damage in the CA1 region of the hippocampus 5 days after surgery. Pergolide 0.5 and 1.0 mg/kg i.p. provided significant (P < 0.05 and P < 0.01, respectively) neuroprotection against the ischaemia-induced hippocampal damage. Bromocriptine and lisuride also provided significant (P < 0.05) neuroprotection, but only at the higher 1.0 mg/kg dose. In contrast, the dopamine D2 receptor antagonist (haloperidol), the dopamine D1 receptor agonist (SKF 38393) and the dopamine D1 receptor antagonist (SCH 23390) failed to provide any neuroprotection in the model. These results support studies indicating that dopamine is important in ischaemic situations. The results also indicate that dopamine D2 receptor agonists are neuroprotective against ischaemia-induced brain injury and may play a role in neurodegenerative disorders.

Experimental and clinical methods in the development of anti-Alzheimer drugs

Methodology used for the development of anti-Alzheimer's disease (AD) drugs raises specific problems which are rarely examined in the literature. While the general development scheme is similar to that required for most drugs, some specific aspects must be analyzed, highly dominated by the dual goal of pharmacology, i.e., to obtain both symptomatic and etiopathogenic drugs. During preclinical studies, aged or lesioned animals are mainly useful for symptomatic drugs, whereas transgenic models or neurodegeneration-induced techniques would probably lead to etiopathogenic drugs potentially slowing down the process of AD. The first administrations of a new compound to human beings raise the question of the activity measurement techniques. Psychometry remains the most informative procedure to detect and analyze the activity of the drugs on the different components of cognition. Electrophysiology and neuroimaging need some complementary studies before they can be proposed as surrogate criteria in phase III trials. At this stage of development, American and the recently published European guidelines are of great help while insisting on long-term (6 months) placebo controlled trials with the use of the triple efficacy criterion: an objective cognition scale, a global assessment, and the opinion of the caregiver. In the long term, pharmacoepidemiology and pharmacoeconomy will have to confirm the rationale of this recent progress in the methodology of anti-AD drug development.

Lisuride prevents learning and memory impairment and attenuates the increase in extracellular dopamine induced by transient global cerebral ischemia in rats

In this experiment, we tested the efficacy of neuroprotection with lisuride, a dopamine agonist, using the 4-vessel occlusion rat model. Functional improvement was evaluated with two behavior tests exploring learning and memorization capacity in the rat, the Morris water maze and the 14-unit T-maze, 18 days after ischemia. Extracellular dopamine levels during ischemia were determined in search of a possible neuroprotection mechanism. Dopamine and its metabolites, DOPAC and HVA, as well as the serotonin metabolite, 5-HIAA, were assayed with HPLC-EC, in striatal extracellular fluid obtained by in vivo microdialysis in the awake rat. Lisuride was administered at a total dose of 10 ng by continuous intrastriatal infusion or at the dose of 0.5 mg/kg by i.p. infusion, 160 minutes before onset of ischemia for the neurochemical study and at the dose of 0.5 mg/kg via i.p. infusion, 1 hour before occlusion of the carotid arteries, for the behavior tests. Behavioral testing showed significantly better recovery in both sets of behavioral tests, with more pronounced positive results with the 14-unit T-maze, in comparison with the saline-treated animals. Microdialysis confirmed a significant attenuation of the ischemia-induced dopamine surge, whatever the mode of administration, compared with saline-treated animals. These results show that lisuride offers significant neuroprotection from the effect of experimental transient global forebrain cerebral ischemia in the rat; the mechanism would imply, at least in part, reduced levels of extracellular dopamine.

Effect of normal aging and of Alzheimer's disease on, episodic memory

Performances of 12 patients with Alzheimer's disease (AD), 15 healthy elderly subjects and 20 young healthy volunteers were compared on two episodic memory tests. The first, a learning test of semantically related words, enabled an assessment of the effect of semantic relationships on word learning by controlling the encoding and retrieval processes. The second, a dual coding test, is about the assessment of automatic processes operating during drawings encoding. The results obtained demonstrated quantitative and qualitative differences between the population. Manifestations of episodic memory deficit in AD patients were shown not only by lower performance scores than in elderly controls, but also by the lack of any effect of semantic cues and the production of a large number of extra-list intrusions. Automatic processes underlying dual coding appear to be spared in AD, although more time is needed to process information than in young or elderly subjects. These findings confirm former data and emphasize the preservation of certain memory processes (dual coding) in AD which could be used in future therapeutic approaches.

Is chlormethiazole neuroprotective in experimental global cerebral ischemia? A microdialysis and behavioral study

Chlormethiazole, an anticonvulsive agent, has been shown to have a possible neuroprotective effect against cerebral ischemia. In addition, chlormethiazole inhibits methamphetamine-induced release of dopamine, protecting against this neurotransmitter's neurotoxicity. The aim of this work was to ascertain whether, in experimental cerebral ischemia, chlormethiazole administration attenuated the ischemia-induced rise of the extracellular concentration of aminergic neurotransmitters and whether it reduces ischemia-induced deficits in memory and learning. Histology for assessment of ischemic damage was a so included. The four-vessel occlusion rat model was used to induce global cerebral ischemia. Aminergic neurotransmitters and their metabolites in the striatal extracellular fluid obtained by microdialysis were assayed by high-performance liquid chromatography-electrochemical detection. The drug was administered either IP (50 mg/kg-1) or directly through the dialysis probe (30 microM) 80 min before ischemia. For the behavioral test and histology, the drug was given IP (100 mg/kg-1) 1 h postischemia. The results obtained did not demonstrate any statistically significant evidence that chlormethiazole has an effect on the ischemia-induced rise in extracellular dopamine and serotonin levels. There was also no variation in metabolite levels. Behavioral measures (learning, recall) were not changed appreciably by the treatment. We observed no significant cell protection in the hippocampus (CA1, CA1), striatum, and entorhinal cortex in animals treated with chlormethiazole. We conclude that, under our experimental conditions, chlormethiazole has little or no effect on the neurochemical, neurobehavioral, and histological consequences of global cerebral ischemia.

Assessment of procedural memory in Parkinson's disease

1. Findings in cognitive psychology and neuropsychology have led to consider the existence of several mnestic systems. This study focuses on a now clearly established distinction between the procedural and the declarative memories. 2. The aim of the present study was to try and determine which of the two acquisition steps (learning and automation) is affected by Parkinsonians' mnestic difficulties, and to verify if these difficulties are linked to the skill content (declarative or motor). 3. To answer these questions, 20 Parkinsonians under treatment underwent specific tests: the maze test and the arithmetic alphabet test. 4. Results show that, by comparison with 20 matched healthy individuals, the deficiencies observed in Parkinson's disease affect both the declarative and the motor skills. In addition, Parkinsonians suffer difficulties in both acquisition steps: learning and automation. 5. These results could account for the cognitive and motor disturbances observed in Parkinson's disease; these abnormalities should be among the pharmacological targets in future.

The dopamine agonists lisuride and piribedil protect against behavioural and histological changes following 4-vessel occlusion in the rat

The 4-vessel occlusion model of ischaemia in the rat was used to assess the effects of two dopaminergic agonists, lisuride and piribedil, on some behavioural and histological changes. Animals were either sham-operated, subjected to 20 min 4-vessel occlusion, or administered lisuride (0.5 mg/kg i.p.) or piribedil (10 mg/kg i.p.) 1 h before 20 min 4-vessel occlusion. Both drugs attenuated deficits in neurological testing, Morris water maze and 14-unit T-maze (p < 0.05). Extensive neuronal death was observed in the CA1, CA3 and CA4 regions of the hippocampus of 4-vessel-occluded animals. Pretreatment with both lisuride and piribedil provided protection against cell death in the hippocampal regions. These findings suggest dopamine may play a role in cerebral ischaemia and dopaminergic agonists may be beneficial in preventing ischaemia-induced neurodegeneration.

Procedural memory and Parkinson's disease

A detailed analysis of the mnestic deficits associated with Parkinson's disease (PD) contributes to explaining the cognitive disorders and their well documented consequences. This study was designed to show that, in PD declarative as well as procedural memory is severely impaired. Three tests designed to explore this aspect of mnestic functioning were proposed to a group of 16 parkinsonian patients whose motoricity was controlled: inverted reading, braille reading, sound form association. The results obtained, compared with those of young and aged controls, show that PD is associated with marked deficits in both declarative and procedural memory. Declarative memory impairment was similar to that observed in the control population (healthy elderly subjects, age-matched with the PD patients) but more marked in PD subjects. The procedural memory deficit was linked with age and pathology. Procedural memory involves a variety of processing modules dedicated to the type of information (visual, auditive, tactile codes). The deficits observed were more like a loss of automatism than procedural impairment stricto sensu ('knowing how'). It would be worth pursuing research by studying akinesia and motor disorders from the angle of automatic memory impairment.

Explicit and procedural memory in Parkinson's disease

One of the aims of cognitive psychology is to breakdown complex tasks into their most basic components. The components of explicit (declarative) and implicit (procedural) memory were thus analyzed in undemented, non-depressed Parkinsonian patients under anti-Parkinsonian treatment, and compared with young and elderly healthy subjects. Three series of experiments were conducted in 61 patients in total. Statistically significant results revealed an impairment of explicit memory (verbal recall of words and drawings) with preserved recall of faces, in Parkinsonians. Implicit memory was also deficient, only in association tests (sound-form; arithmetical alphabet) and maze tests. Braille reading tests and Toronto tower tests did not discriminate between Parkinsonians and elderly subjects. Lastly, analyzing learning and automation revealed a dysfunctioning in Parkinsonian patients. All these data indicate a dysregulation of the cortical-sub-cortical systems, not essentially pre-frontal, and not necessarily dopaminergic. Cognitively, it appears that procedural and implicit memories should be dissociated conceptually.

[Role of isotopic imaging in intensive care]

The real place of isotopic imaging in intensive care patients remains still unclear. This review aimed to consider the indications of isotopic imaging for improved diagnosis and therapy and to specify its place among the other techniques of exploration. Pulmonary perfusion and ventilation scintigraphies are valuable for the diagnosis of pulmonary embolism (PE). A "high probability" scintigraphy of the lungs ascertains the diagnosis of PE and allows to start a specific treatment without requiring a pulmonary angiography. This is not the case in the presence of a history of previous PE or if the arguments for a PE are only weak. A normal lung scintigraphy eliminates the diagnosis of a clinically significant PE all the more as an exploration of good quality of the lower limb veins remains negative. In the opposite a "non diagnostic" scintigraphy justifies a pulmonary angiography in intensive care patients. The diagnosis of myocardial contusion is made uneasy as the clinical symptoms, the ECG, the cardiac enzymes and the chest X-ray are only of limited value. Isotopic explorations of the heart could provide additional valuable data or be an alternative for 2 D echocardiography. The comparison of CPK-MB concentrations with a myocardial scintigraphy using thallium 201 is given as being very reliable, with positive and negative predictive values higher than 80%. An exploration restricted to the cardiac ejection fractions is only of limited value. In the future, an improvement will perhaps be obtained with tracers such as MIBI labelled with technetium 99m, which allow the simultaneous assessment of myocardial perfusion and the ventricular ejection fractions as well. The localisation of centres of infection, especially when intra-abdominal, remains difficult in intensive care patients. Isotopic imaging, especially the scintigraphies with labelled polynuclears, could allow in combination with conventional imaging techniques (computed tomography and 2 D echocardiography) to prevent from errors in diagnosis. An array of arguments is essential for ascertaining the presence of an abscess. Scintigraphies with leucocytes labelled with indium 111 or technetium 99m are qualified as having a sensitivity and a specificity greater than 90%. The conventional techniques of measurement of the cerebral blood flow (CBF) using xenon 133 require a special equipment or are invasive. Other cerebral tracers, such as cyclic amines (HMPAO) labelled with technetium 99m and administrable by i.v. route, allow the use of a standard tomo-gamma camera, and could be of help in various pathological conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

Sequence of pig lens aldose reductase and electrospray mass spectrometry of non-covalent and covalent complexes

The complete sequence of pig lens aldose reductase (EC 1.1.1.21), a member of the nicotinamide coenzyme-dependent aldo-keto reductase super family, was determined by the combined use of data obtained from Edman degradation, fast-atom-bombardment mass spectrometry and electrospray mass spectrometry. The N-terminal residue of human and pig aldose reductase was shown to be acetylated. The assignment of a disulfide bridge (Cys298-Cys303) was obtained by mass spectrometry. Electrospray mass spectrometry has been used for molecular mass measurement of human muscle (35758 +/- 7 Da) and pig lens (35778 +/- 3Da) aldose reductase; using mild ionization conditions, it has also been used to study the reversible interaction involved in a non-covalent complex with NADP+ (36527 +/- 4Da). An alkylating analog of NADP+ (3-chloroacetylpyridine-adenine dinucleotide phosphate) was used as an irreversible inhibitor to investigate the NADP binding site and the mass of the covalent complex was measured (36521 +/- 3 Da).

Reversal of learning and memory impairments following lesion of the nucleus basalis magnocellularis (NBM) by concurrent noradrenergic depletion using DSP4 in the rat

In the following study the behavioural effects of simultaneous lesion of the nucleus basalis magnocellularis (NBM) using ibotenic acid and noradrenergic depletion following a single i.p. administration of DSP4 (50 mg/kg) were examined in the rat. NBM lesion induced a deficit in acquisition of a reinforced T-maze alternation task, a working memory adaptation of a spatial navigation task in a water maze and 24 h retention in a passive avoidance task compared to sham controls. No effect of the lesion on a reference memory version of spatial navigation in a water maze task was found. Animals that received a combination of NBM lesion and DSP4 treatment showed no impairment on any of the tasks that were impaired by NBM lesion alone. This indicates a reversal of the learning and memory deficits consequent to NBM lesion by simultaneous noradrenergic depletion. NBM lesion induced a significant reduction in choline-acetyltransferase activity in the frontal cortex, and DSP4 induced a significant decrease in noradrenaline concentration in occipital cortex and hippocampus, confirming the effects of these treatments. These results suggest an interaction between central noradrenergic and cholinergic systems in learning and memory processes.

Purification and electrospray mass spectrometry of aldose reductase from pig lens

Aldose reductase (alditol: NADP+ 1-oxidoreductase, EC 1.1.1.21) has been purified from pig lens to homogeneity by a rapid and efficient three-step procedure involving poly(ethylene glycol) fractionation, ion-exchange chromatography and chromatofocusing. The homogeneity of the purified enzyme was examined by polyacrylamide gel electrophoresis under native and denaturing conditions, by isoelectric focusing and by high-performance liquid chromatography on a size-exclusion column. The highly purified enzyme is a monomeric protein with a molecular mass of 35,775 +/- 3 Da as determined by electrospray mass spectrometry (ESMS). This purification procedure is particularly suited for the preparation of triclinic single crystals of pig lens aldose reductase, which are currently used in X-ray studies of this enzyme.

Novel NADPH-binding domain revealed by the crystal structure of aldose reductase

Aldose reductase is the first enzyme in the polyol pathway and catalyses the NADPH-dependent reduction of D-glucose to D-sorbitol. Under normal physiological conditions aldose reductase participates in osmoregulation, but under hyperglycaemic conditions it contributes to the onset and development of severe complications in diabetes. Here we present the crystal structure of pig lens aldose reductase refined to an R-factor of 0.232 at 2.5-A resolution. It exhibits a single domain folded in an eight-stranded parallel alpha/beta barrel, similar to that in triose phosphate isomerase and a score of other enzymes. Hence, aldose reductase does not possess the expected canonical dinucleotide-binding domain. Crystallographic analysis of the binding of 2'-monophospho-adenosine-5'-diphosphoribose, which competitively inhibits NADPH binding reveals that it binds into a cleft located at the C-terminal end of the strands of the alpha/beta barrel. This represents a new type of binding for nicotinamide adenine dinucleotide coenzymes.

Comparison of three regimens of Parlodel-SRO in levodopa-treated parkinsonians: a randomized double-blind crossover study

Parlodel-SRO is a newly developed slow-release formulation of bromocriptine, which prevents initial plasma peak--a known source of adverse events--and extends the half-life of the compound, an interesting feature for the management of motor symptoms in Parkinsonians. This study was designed to determine the best daily administration schedule for 30 mg Parlodel-SRO in 18 parkinsonians previously treated with levodopa and standard Bromocriptine (Br). The 30 mg dose was replaced from one day to the next, in a randomized, double-blind latin square design trial. Three consecutive 7-day courses were implemented, during which a total daily dose of 30 mg P-SRO was administered in one dose, two intakes (b.i.d.) and three intakes, (t.i.d.) respectively. The b.i.d. schedule produced the best improvement in UPDRS scores, especially as to postural stability, walking, bradykinesia; it also provided greater pharmacological stability throughout the assessment day. Adverse event analysis was not in favor of a single daily dose. It appeared that P-SRO administered in two 15 mg intakes (morning and evening) produces the best benefit-risk ratio in Parkinsonians who were already being treated with levodopa.

Randomized double-blind trial of injectable heptaminol for controlling spontaneous or bromocriptine-induced orthostatic hypotension in parkinsonians

Heptaminol is a molecule with experimental cardiovascular analeptic properties. In this double-blind vs placebo trial, the potency, so far unproven, of the injectable form of a 626 mg dose of heptaminol chlorhydrate on spontaneous or induced orthostatic hypotension (OH), was assessed. Nineteen patients were included in the study: 7 displayed spontaneous OH, and in the other 12 OH was induced by bromocriptine, as monitored 103 min/after an oral intake of 6.6 mg on average. Neither spontaneous nor induced OH were recorded in 32% of the Parkinsonian population registered, with no obvious distinctive characteristics. Potency tilt-trials, performed 15, 30 and 45 min after parenteral administration of heptaminol, revealed a significant and expressive potency of the molecule on the systolic blood pressure after 15 min (P less than 0.05). Clinical and biological tolerance was excellent. Low plasma renin activity and the absence of response to orthostatism indicated, in this population of Parkinsonian extrapyramidal syndromes, a loss in positive tonus likely to be of sympathetic origin. The anti-hypotensive action of heptaminol does not seem to be related to any renal or even sympathetic interaction.

Progress in understanding the pathophysiology of cerebral ischemia: the almitrine-raubasine approach

Cerebral ischemia occurs frequently and is disabling. In addition to preventing and correcting risks factors, drugs prevent cell death induced by ischemia-hypoxia. Precise knowledge of the pathophysiology of cerebral ischemia is the prerequisite for drug development, and the main proofs of efficiency are histopathological and clinical (i.e., the results of controlled studies). Different animal models are considered valid for global, focal, or multifocal ischemia. These models have enabled the identification of deleterious phenomena that could be corrected or neutralized by drugs: hypoxia, lactic acidosis, release of neurotransmitters, influx of calcium, activation of phospholipase A2, release of excitatory amino acids, excess of free radicals, and neuronal cell metabolic paralysis (decrease of oxygen and glucose consumption). The chronology of these events clearly described herein will prompt the choice of the best drug, based on the delay between the ischemic event and the decision to treat. The main pharmacological effects required are the following: antagonism of hypoperfusion, oxygenation improvement, blockade of calcium influx and neurotransmitters action, reduction of acidosis and potassium efflux, blockade of arachidonic cascade and free radicals production, and antiedematous effect. The analysis of almitrine-raubasine (Duxil) pharmacological properties will be used as an example of these potentially anti-ischemic drugs. Almitrine-raubasine pharmacological studies indicate that this drug has several beneficial effects on cerebral ischemic processes. These studies have dealt with effects of hypobaric hypoxia on deoxyglucose uptake in the rat, protective effects on permanent or temporary cerebral ischemia-induced neurobehavioral problems in the gerbil, and preservation of the glycogen content and of the swelling in astrocytes after bilateral occlusion of the carotid arteries in the rabbit.

Comparative evaluation of scavenger properties of exifone, piracetam and vinburnine

The involvement of radical reactions in the ageing process, physiological as well as pathological, is well demonstrated. It is accepted that alloxan cyto-toxicity is linked to a production of hydroxylated free radicals and that a substance preventing the development of alloxanic diabetes possesses scavenger properties. The objective of this work was to demonstrate, in this model, the anti-radical effect of 3 molecules recommended in the treatment of cerebral insufficiency and a reference substance (+)-catechin. We observed a protective action with catechin (P less than 0.05) at the highest dose (100 mg/kg). PEG alone was moderately active but comparison of PEG-alloxan and PEG-exifone-alloxan showed a highly significant difference (P less than 0.001) at the two highest doses (60 and 120 mg/kg). Piracetam (200 and 400 mg/kg) and vinburnine (7.5 and 15 mg/kg) were inactive. Under these experimental conditions, exifone demonstrated remarkable anti-radical properties.

Randomized, double-blind trial of exifone versus cognitive problems in Parkinson's disease

Exifone is a novel substance of the benzophenone group that possesses potent scavenging properties. Initial findings demonstrate beneficial effects on age-related cognitive disorders. In this double-blind clinical trial versus placebo, the efficacy of 2 dosages (600 and 1200 mg/d) was evaluated with regard to Parkinson's disease (PD)-related cognitive disorders, for which there is increasing suspicion of a free-radicals origin. Despite disparities between the treatment groups as assessed by validated scales and subtests, and a considerable placebo effect on main parameters, both dose levels of exifone produced statistically significant improvement of the cognitive items most commonly impaired by PD: immediate recall, naming of objects presented, spatiotemporal orientation, and calculation. These properties suggest a new slot for exifone in the range of therapeutics available.

[Cerebral edema: intra-cellular or extra-cellular mechanisms?]

Many cerebral pathological processes are attended by edema defined as an increase in brain volume associated with an increase in brain water and sodium contents. The aggravation of lesions induced by this edema warrants a pharmacological and therapeutic approach based on a detailed knowledge of its physiopathological mechanisms. Experimental models and in vitro studies have shown that the fundamental mechanisms leading to edema are: cold, acute hypoxia, ischaemia, arachidonic acid, toxic substances and plasma hypo-osmolarity. To the various types of edema described (vasogenic, cytotoxic, hydrocephalic) correspond different mechanisms. Vasogenic edema essentially depends on osmotic and hydrodynamic factors; cytotoxic edema results from perturbations in energy-dependent cellular osmoregulation. The underlying biochemical disorders have now been demonstrated, mostly in ischaemic edema; they include, during the revascularization phase, disruption of the blood-brain barrier (vasogenic component) and changes in ion concentrations, neurotransmitters and energetic mechanisms. Key factors in the development of edema are cyclic AMP, serotonin and Na-K-ATPase.

Aminergic neurotransmitter and water content changes in rats after transient forebrain ischemia

We have studied changes of cerebral monoamine metabolism and water content, during recirculation following global transient ischemia (20 min) using the four-vessel occlusion model in rats. Levels of monoamines and their metabolites were determined in cortex, striatum, hippocampus, and hypothalamus. Water content was evaluated by weight and by the analysis of T1 and T2 relaxation times in 1H-nuclear magnetic resonance. Norepinephine levels decreased; 3,4-dihydroxyphenylethylamine, 3,4-dihydroxyphenylacetic acid, and 5-hydroxytryptamine levels oscillated and levels of the end products homovanillic acid and 5-hydroxyindole-3-acetic acid increased. The regional changes were qualitatively similar but quantitatively different, and were greatest in the hippocampus, illustrating the concept of neuronal selective vulnerability. The changes suggest an initial monoamine depletion and catabolism due to massive release from stores followed by autoregulatory processes. The water content increased moderately, with a maximum at 1 h. The variations of T1 were similar, positively correlated with water content and more pronounced in the cortex than in the white matter. T2 was markedly altered over the entire 24-h period. Those latter parameters are positively correlated with 5-hydroxytryptamine concentration in the hypothalamus consistent with a relationship between 5-hydroxytryptamine and cerebral edema.

[Modification of aminergic neurotransmitters and neurobehavioral correlates in acute cerebral ischemia in the rat]

Aminergic neurotransmitters and their main metabolites concentrations are measured in four areas (posterior cortex, striatum, hippocampus, hypothalamus) of the rat brain, 24 hours after an acute ischemic injury (created by the occlusion of the four cephalic vessels). Simultaneously, spontaneous motility and neurological status are evaluated. The main results are the increase of 5 HIAA in striatum, hippocampus and cortex, associated with an increase of HVA in striatum. Motility as well as neurological scores are significantly decreased in ischemic animals when compared with controls. The conclusion is that this model of cerebral ischemia is may be useful for pharmacological assessment of drugs liable to antagonize cerebrovascular disorders.

[Anti-cerebral edema properties of PEG 300 in triethyltin poisoning]

The polyethylene glycols (PEG) frequently used as solvents of non hydrosoluble molecules present toxic and pharmacodynamic properties. The effect of PEG 300 (10 ml/kg) on the modifications of the central nervous system (CNS) previously induced by a subchronic intoxication with triethyltin salt (TEE) (2 mg/kg p.o. for 5 days) has been studied in rat. The following parameters are recorded: measure of brain edema, concentration of the aminergic neurotransmitters in four different brain areas, neurological status, behaviour, mortality. The PEG 300 antagonizes or reduces some of the effects of the TEE: edema, behavioral disturbances, mortality. On the opposite, no change in the amines and their metabolites induced modifications is observed. This selective antagonism towards some of the components of TEE brain toxicity brings more information on pharmacological properties of this solvent and opens a discussion on the role of neurotransmitters on brain edema.

Effect of triethyltin chloride on the central aminergic neurotransmitters and their metabolites: relationship with pathophysiology of aging

Triethyltin (TET) salt intoxication provokes a myelinic vacuolisation associated with a white matter cerebral edema. The central nervous system disturbances accompanying these phenomena (Na-K-ATPase activity, neurological symptoms, water and sodium cerebral content) can be counteracted by drugs used in age-related brain failure; consequently, TET intoxication could be suggested as an experimental model for studying the aging process. The aim of the present study is to follow-up the biogenic amine concentrations in different brain areas of TET treated rats, knowing that modifications of cerebral amines exist throughout the aging process. The following results are obtained: the cerebral water content of the TET treated rats is significantly increased, confirming the existence of a brain edema. Monoamine concentrations are significantly decreased, specifically noradrenaline (in hypothalamus, mesencephalon, cerebellum); serotonin (in striatum, hypothalamus, mesencephalon); dopamine only in hypothalamus; these are accompanied by an increase of the metabolites 5 HIAA (in striatum and mesencephalon) and HVA (striatum). These modifications are compared to those occurring in physiological aging, and hypothetical mechanisms are reviewed. We conclude that TET intoxication must not be considered as a pathophysiological model of brain aging, but may be considered as a useful pharmacological tool for studying experimental drugs liable to counteract brain age-induced disturbances.

Impairment of acquired temporal response regulation of rats under normobaric hypoxia

Effects of hypoxia on learning involving temporal regulation of behaviour was investigated. Under 10% hypoxia there was a decrease in the number of conditioned responses, and the 'efficiency' of reinforcement, but no modification of temporal discrimination. Normobaric hypoxia may be a useful model for studying certain behavioural and pharmacological effects of cerebral circulatory insufficiency, and their implications at the level of the central nervous system, but it would be incorrect to use such a model to study factors that might prevent the loss of acquired knowledge.

[Pharmacokinetics of intravenous ranitidine and its effect on gastric acid secretion stimulated by pentagastrin in the cirrhotic]

The pharmacokinetics of 50 mg intravenous ranitidine and the consequences on pentagastrin (2 micrograms/kg/h)-stimulated gastric acid secretion were studied in ten cirrhotic patients. Group I (n = 5) included patients without ascite; group II (n = 5) was characterized by the presence of ascites. Blood creatinine was normal in all the subjects. In non-ascitic cirrhotic patients, pharmacokinetic parameters are similar to those published in healthy subjects. In group II ascitic cirrhotic patients, the half-life is significantly increased by 50 p. 100 (P less than 0.05), as compared to group I, due to a 38 p. 100 decrease of total clearance and to a 45 p. 100 decrease of renal clearance (P less than 0.05). Hepatic clearance and volume of distribution are similar in both groups. The percentage of the inhibition by ranitidine of pentagastrin-stimulated acid out-put, in 6 cirrhotic patients, is 95 +/- 4 p. 100 (SD) when measured at the maximal inhibition peak, and 71 +/- 4 p. 100 (SEM) on the average, during the 3 h following the injection. In conclusion, ranitidine may be considered as an effective anti-secretory drug in cirrhotic patients; the pharmacokinetic variations observed in ascitic cirrhotic patients are the result of the decrease of ranitidine renal clearance.

[Epidural anesthesia using the bupivacaine-fentanyl combination for cesarean section]

This prospective study was designed to evaluate the benefit of a bupivacaine-fentanyl mixture vs bupivacaine alone in epidural anaesthesia for caesarean section. In 10 women, 0.5% bupivacaine (1.18 ml per metamer) was injected in the epidural space. In 20 women, 0.5% bupivacaine (1.06 ml per metamer) was injected by the same route together with fentanyl (1.70 +/- 0.09 micrograms X kg-1). The bupivacaine-fentanyl group showed a significantly shortened onset of analgesia (p less than 0.001), as well as a significant reinforcement of this analgesia graduated from 0 to 4 (p less than 0.01 at 25 min, p less than 0.001 at 75 min and at the maximum of pain, for the two sets of scores). All the Apgar scores were maximal at 5 min. No clinical respiratory depression was observed in either the mothers or the neonates. Fetal and maternal blood concentrations were in favour of respiratory innocuousness of the method (peak fentanyl concentrations: in mothers 1.5 ng X ml-1, in neonates 0.8 ng X ml-1). Fentanyl never induced any significant haemodynamic variations. Pruritus and nausea respectively occurred in six and two patients respectively in the bupivacaine-fentanyl group. In conclusion, in caesarean section, the adjunction of fentanyl to bupivacaine significantly improved analgesia without any clinical respiratory depression both in the mother and the neonate.

[Study of three biocides (dimethoate, parathion ethyl and zineb) on female rat neuro endocrinological balance (author's transl)]

The authors studied the neuro endocrinological effects of three pesticides. Two of them were organophosphorus compounds (ethyl parathion and dimethoate) and one was a carbamate (zineb). Mature female rats have been orally administered these compounds for 16 days at respectively 1/25, 1/10 and 1/10 of the LD50. The parameters recorded are: the gonadotropins, the length of estrous cycle and the weight of the anterior pituitary gland, the ovaries and the uterus. In contradistinction with the organochlorine compounds the organophosphorus did not induce any disturbances in the neuro endocrinological system, whereas the carbamate compound decreased the pituitary gonadotropins.

[Comparative effects of seven beta adrenolytic agents on blood pressure after injection into the posterior hypothalamus of rats. The frequency heart and the plasma renin activity (author's transl)]

The author's studied the central action of seven beta-blocking agents: alprenolol, atenolol, bupranolol, oxprenolol, pindolol, practolol, propranolol. The drugs were stereotactically injected into the posterior hypothalamus of non anaesthesized rats. Three dosages were used. Blood pressure, heart rate and plasma renin activity (PRA) were recorded. 2. The seven beta-blocking drugs used decreased heart frequency for at least one dosages PRA always decreased but blood pressure was lowered only after administration of alprenolol, oxprenolol, pindolol. 3. The discussion deals with: --the specificity of the target, --the involvement of the central beta receptors into the PRA regulation, --the correlations between the cardiovascular responses and the pharmacological properties of the different molecules; the hypothetic role of the intrinsic activity is postulated --the dissociation between heart rate and blood pressure responses, suggesting the existence of two different receptors for the specific control of those two parameters.

[Drugs and indications for medical treatment in Parkinson's disease (author's transl)]

The authors present a review of the actual drugs efficient in the treatment of Parkinson's disease. They emphasize the frequency of the side-effects and consequently to the difficult management of Parkinsonism. The indications are schematically summed up.

[Effect of ascorbic acid during acute iterative anoxia, hypothesis of an anti-oxidizing mechanism of action in comparison with the effect of hydroquinone]

Some of the problems which appear during senescence, are said to be caused by cerebral oxygen deficiency and various experiments have been set up to try to imitate this particular aspect of the ageing process. We have already studied the action of many drugs with regard to acute repeated anoxia. Our work has given us clear evidence of the activity of ascorbic acid, which delays the moment of electroencephalographic silence in rats and decreases the latent period up to the reappearance of electrical activity. In order to pinpoint the mechanism of action, we compared the influence of lysine aceto-salicylate with that of hydroquinone. Very small doses of the latter drug produce a marked effect and lead us to put forward the hypothesis that it may be anti-oxydising. However, although all the drugs which proved effective in these experiments may be grouped together (despite their varying pharmacological profiles) and described as "anabiotic" drugs, it is not possible to revert to a single mechanism of action for the group as a whole.

The use of bromocriptine for testing central dopaminergic reactivity

A single oral intake of 10 mg of Bromocriptine can modify both plasma renin activity (PRA) and arterial blood pressure (BP). The changes in both variables depend on the integrity of the central dopaminergic systems. The parkinsonians whose extrapyramidal symptoms are markedly improved by L-Dopa in association with a decarboxylase inhibitor (IDC) and the untreated parkinsonians are the only patients whose PRA and BP are lowered 1 h after Bromocriptine ingestion. The results obtained in the L-dopa-induced dyskinetic parkinsonians are similar to those obtained in the group of L-Dopa-resistant patients. This points to the paradoxical hypothesis of dopaminergic hyposensitivity in the dyskinetic patients. In spite of the absence of correlation between PRA and BP, it is possible that lowering of BP by Bromocriptine is linked to the parallel decrease of PRA. An increase of the BP may be obtained in the dyskinetic and L-Dopa-resistant groups. These data point to a possible involvement of central dopaminergic systems in some aspects of hypertension.