Effects of NMDA administration in the substantia nigra pars compacta on the striatal dopamine release before and after repetitive exposures to nitrogen narcosis in rats.

Hyperbaric nitrogen-oxygen exposure developed in rats a decrement of the striatal dopamine release, which was reversed by repetitive exposures. This dopamine decrease could be the result of the antagonistic effect of nitrogen on NMDA receptors. The increment of the dopamine release, following repetitive exposures to nitrogen, could be attributed to a desensitisation of NMDA receptors to the effects of nitrogen. To test these hypotheses, male Sprague-Dawley rats were implanted with electrodes in the striatum to measure dopamine release by voltammetry and cannula in the substantia nigra pars compacta for NMDA injection. Free-moving rats were exposed up to 3MPa of nitrogen-oxygen mixture before and after 5 exposures to 1MPa. At the first exposure to 3MPa, the dopamine level decreased (-15%) but is counteracted by NMDA administration. In contrast, after repetitive exposure, the second exposure to 3MPa, induces a 10% dopamine increase. NMDA administration significantly potentiated this increase. Our results neither support the hypothesis of an antagonist effect of nitrogen on NMDA receptors at the first exposure, nor that of a NMDA receptor desensitization following repetitive exposures to hyperbaric nitrogen.     

Large volume injection and infiltration system

Summary A system which can be used for injection or infiltration of large volumes of fluid is described. This consists of a syringe which fills automatically from a reservoir through an inlet/outlet valve.     

Pharmacotherapy of psychiatric emergencies

The psychiatric emergency service has become a major provider of psychiatric care over the past decade. Concomitant with this growth has been an emphasis on pharmacological treatment. While rapid tranquilization is the best known and most frequently used intervention, a growing diagnostic awareness has led to a variety of other chemotherapeutic approaches. The current reviews of pharmacologic intervention in the psychiatric emergency service do not detail the variability of treatment approaches or examine alternative treatment approaches. The goal of this article is to critically review current pharmacologic treatments and address areas in which there is no consensus in treatment approach. From this review the authors suggest guidelines for pharmacotherapy of psychiatric emergencies. The authors discuss rapid tranquilization, the treatment of alcohol and drug intoxication and withdrawal, and anxiety disorders.     

Abnormalities of fine motor control in schizophrenia

Response time and fine motor control during a classification task were examined in schizophrenics and nonschizophrenics. The task involved decisions about either the sensory characteristics of auditory and visual stimuli or the referential meanings of spoken words and viewed pictures. Nonschizophrenics responded more quickly and exhibited a smoother and faster motor response on all tasks. Response time and motor control were influenced by stimulus modality and the complexity of the classification task in both groups. In the analysis of motor control, the schizophrenics differed from the nonschizophrenics in exhibiting a pattern suggestive of a specific difficulty with decisions involving referential meaning. The observed motor control dysfunction in schizophrenics is a psychomotor deficit similar to previously reported abnormalities in smooth pursuit eye movement. Further, the interaction of group and task variables in the motor response suggests that decisions about the abstract referential meaning of words and pictures produce greater cognitive loads in schizophrenics than in nonschizophrenics.     

Gabapentin-induced coma: A MR-spectrometry analysis

As for the majority of antiepileptic drugs, encephalopathy, manifested by transient somnolence, mood and motor disorders, is a possible side-effect. To our knowledge, there is little information about gabapentin-induced coma. We report a third case of gabapentin-induced coma where magnetic resonance-spectrometry was performed in diagnosis assessment.     

A randomized trial comparing two different approaches of pacemaker selection.

AIMS: DDD-pacemakers are favoured in patients with sick-sinus-syndrome or AV-block. However, AAI-pacemakers for sick-sinus-syndrome or VDD-pacemakers for AV-block may provide similar benefit with lower costs. The aim is to show that a tailored approach (TA) with arrhythmia-specific pacemaker selection was equal to a standard approach (SA) regarding quality of life (QoL) at lower costs. METHODS AND RESULTS: The study was prospective and randomized with QoL as primary endpoint. Secondary endpoints were a combined endpoint of all-cause mortality, worsening heart failure or angina, atrial fibrillation (AF), stroke, these endpoints individually and costs. Of 198 patients (age 77 +/- 10 years, 43% female, ejection fraction 54 +/- 12%, follow-up 38 +/- 15 months), 94 were randomized to SA and 104 to TA. Thirty-two patients (34%) died in the SA group vs. 25 (24%) in the TA (P= ns). QoL showed no differences in all dimensions. The combined secondary endpoint was reached more frequently with SA (51%) compared to TA (37%, P = 0.045). There was no difference regarding all single secondary endpoints. Hardware costs were reduced by 15% (P < 0.0001). CONCLUSION: In long-term follow-up, a TA is equal to SA regarding the primary endpoint QoL and secondary endpoints as AF and mortality. Depending on the healthcare system, it may significantly reduce costs.     

Prefrontal cortex dysfunction and depression in atypical parkinsonian syndromes.

Depressive symptoms are common in patients with neurodegenerative disorders. Imaging studies suggest that a disruption of frontal-subcortical pathways may underlie depression associated with basal ganglia disease. This pilot study tested the hypothesis that frontal dysfunction contributes to depression associated with multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). Depressed patients with MSA (n = 11), PSP (n = 9), and age-matched controls (n = 25) underwent measures of cerebral glucose metabolism applying positron emission tomography with (18)F-fluorodeoxyglucose. Regional metabolism in the patient groups was compared to the normal subjects using the voxel-based statistical parametric mapping. Depressive symptom severity (Hamilton Depression Rating) and degree of locomotor disability (Hoehn & Yahr) were assessed in the patient groups. The association between prefrontal metabolism and the occurrence of depressive symptoms and the degree of locomotor disability was investigated. When compared to controls, MSA patients revealed significant metabolic decreases in bilateral frontal, parietal, and cerebellar cortex and in the left putamen. In PSP patients, significant hypometabolism was demonstrated in bilateral frontal cortex, right thalamus, and midbrain. Depression severity but not the patients' functional condition was significantly associated with dorsolateral prefrontal glucose metabolism in both patient groups. The findings of this pilot study support the hypothesis that depressive symptoms in MSA and PSP are associated with prefrontal dysfunction.