Clinical Neuroscience

[The role of ventromedial prefrontal cortex in addictological disorders]

KELEMEN Oguz, MÁTTYÁSSY Adrienn, KÉRI Szabolcs

FEBRUARY 10, 2004

Clinical Neuroscience - 2004;57(01-02)

[Recently a significant conceptual change emerged in the interpretation of addictological disorders. Despite this significant progress, the exact neuronal mechanisms of these disorders are still unknown. By the development of cognitive neuroscience novel clinical tests became available which are devoted to the evaluation of more properly defined neuronal structures. These novel approaches are designed to separately investigate memory/attention-related and affective processes in decision- making. These investigations along with animal models and functional neuroimaging approaches suggest the crucial role of a complex neuronal network in the pathomechanism of addictolo-gical disorders, including the ventromedial prefrontal cortex and the amygdala-accumbens system. The aim of this paper is to review these novel findings in order to gain insight into the neurocognitive mechanisms of addictological disorders.]

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Clinical Neuroscience

[Effect of mental arithmetic and verbal fluency on the flow velocity in the middle cerebral arteries]

AMREIN Ilona, PÁLVÖLGYI László, DEBRECZENI Róbert, KAMONDI Anita, SZIRMAI Imre

[Introduction - Using transcranial Doppler sonography (TCD), changes in blood flow velocity (BFV) can be measured in the Medial Cerebral Artery (MCA) during cognitive effort. Our goal was to define the time-course and laterality of BFV in healthy vo-lunters during arithmetic and verbal fluency tasks according to handedness. Methods - Twelve subjects (8 right-handed, 4 left-handed) were assessed. The TCD registered BFV in both MCA simultaneously. Heart rate was also recorded using TCD. Finally we included a 16-channel EEG. BFV laterality index (LI) was calculated. Participants were asked to count silently and generate words beginning with a specified letter. To estimate hemispheric differences in BFV, two-tailed Wilcoxon tests were utilized along with correlational analyses. Results - During cognitive effort the BFV changed in a triphasic manner in all participants. A 6-8% elevation of BFV was observed in MCAs without latency at the time of the evoking signal. Laterality of BFV developed after 5-13 seconds during cognitive effort in right-, and several seconds later in left-handed subjects. During tasks the BFV increased in the dominant hemis-phere up to 2.6-4.7% compared to the subdominant one. We also calculated the LI. During the verbal task the LI agreed with the handedness in 9 out of 12 subjects. During the mental arithmetic task, agreement was found in 6 out of 12 subjects. According to LI results we found a discrepancy between verbal and arithmetic tests in 3 out of 12 subjects. Conclusion - Cognitive effort elicites significant bilateral BFV increases in the MCAs, which suggests fast neurogenic regulation. The course of BFV during mental arithmetic proved to be different from course BFV assessed during the word fluency task. Based on the laterality of the BFV, the word-generation task was more sensitive in determining the dominant hemisphere when compared to the mental arithmetic task. The use of LI may help to estimate hemispheric functions even in pathologic circumstances.]

Clinical Neuroscience

[A novel analgesic made from cannabis]

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[Bayer AG has recently announced that it acquired exclusive rights for the marketing of GW Pharmaceuticals´ new medicine Sativex® in Europe and in other regions. Sativex is a sublingual spray on Cannabis extract basis, and is equipped with an electronic tool to facilitate accurate dosing and to prevent misuses. It is standardized for the THC and CBD. The new analgesic is proposed for the treatment of muscle spasticity and pains accompanying multiple sclerosis and as an efficient analgetic for neurogenic pain not responding well to opioids and to other therapies available. The entirely new mechanism of action through the recently discovered cannabinoid receptor system may offer a real therapeutic potential to the drug. Although the Government of Netherlands has authorized the sale of pharmaceutical grade Cannabis herb by pharmacies in the Netherlands, the availability on the pharmaceutical market of the registered preparation may render requests for the authorization of the smoking of Cannabis herb (marihuana) by individuals suffering of multiple sclerosis, neurogenic pain, AIDS wasting syndrome unnecessary. Nevertheless, the ”old chameleon” plant Cannabis appears to gradually regain its previous status in mainstream therapy and pharmacy. As long as the plant Cannabis and its products continue to be classified as narcotic drugs, medical use of the new preparation will need close supervision.]

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[Introductions - The optimal therapy of brain stem tumours of different histopathology determines the expected length of survival. Authors report 125Iodine interstitial irradiation of brain stem tumours with stereotactic brachytherapy. Case reports - Two patients having brain stem tumours were suffering from glioma or from metastases of a carcinoma. In Case 1 the tumour volume was 1.98 cm3 at the time of planning interstitial irradiation. The control MRI examination performed at 42 months post-op showed a postirradiation cyst size of 5.73 cm3 indicating 65.5% shrinkage. In Case 2 the shrinkage was more apparent as the tumour vo-lume measured on the control MRI at 8 moths post-op was only 0.16 cm3 indicating 97.4% shrinkage of the 6.05 cm3 target volume at the time of brachytherapy with the metastasis practically disappearing. Quick access to histopathological results of the stereotactic intraoperative biopsy made it possible to carry out the 125Iodine stereotactic brachytherapy immediately after the biopsy, resulting in less inconvience for patients of a second possible intervention. The control MRI scans show significant shrinkage of tumours in both patients. Conclusion - The procedure can be performed as a biopsy. The CT and image fusion guided 125Iodine stereotactic brachytherapy can be well planned dosimetrically and is surgically precise.]

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Lege Artis Medicinae

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Clinical Neuroscience

Delirium due to the use of topical cyclopentolate hydrochloride

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Introduction - Our aim is to present a rare case where a child had delirium manifestation after instillation of cyclopentolate. Case presentation - A 7-year old patient was seen in our outpatient clinic, and cyclopentolate was dropped three times at 10 minutes intervals in both eyes. The patient suddenly developed behavioral disorders along with gait disturbance, and complained of visual hallucinations 20-25 minutes after the last drop. The patient was transferred to intensive care unit and 0.02 mg/kg IV. physostigmine was administered. The patient improved after minutes of onset of physostigmine, and was discharged with total recovery after 30 minutes. Conclusion - Delirium is a rare systemic side effect of cyclopentolate. The specific antidote is physostigmine, which can be used in severely agitated patients who are not responding to other therapies.