Central Nervous System Reactions to Cervical Myelography

In a double blind prospective study of side effects to cervical myelography 38 patients were evaluated with neurologic examination, electroencephalography (EEG), brainstem evoked response (BER), somatosensory evoked responses (SSER), and continuous reaction times prior to and at 6 h and 24 h after myelography with either metrizamide or iohexol. A difference in the incidence of side effects (for example headache, dizziness, nausea, and neck pain) to the two different contrast media indicated that the inconveniences related to myelography were not only due to the spinal puncture. A contrast medium effect on the central nervous system varying from one agent to another was present. A high frequency of EEG deteriorations among patients with adverse clinical reactions and on only discrete affection upon BER indicated the reaction to be located to the cerebral cortex. Weakened tendon reflexes and reduced strength in the upper extremities were probably caused by blockade in the motor roots as SSER were normal indicating no affection of the sensory pathways. This hypothesis is in agreement with the fact that the patients were in the prone position in the first phase of the investigation causing the highest concentration of contrast medium around the motor roots and the anterior part of the spinal cord. Difference in metabolic effect may explain differences in side effects of metrizamide and iohexol.

Ozone uptake by an evergreen forest canopy: temporal variation and possible mechanisms

Patterns of ozone concentration ([O(3)]), O(3) deposition velocity (v(d)) and O(3) flux (F(c)) over an evergreen forest canopy are shown in relation to measuring method, physiological activity of the trees, and time of year. The gradient and eddy correlation methods were compared and showed similar diel v(d) patterns. Daytime F(c) was correlated with CO(2) and water vapour fluxes, while no correlation between [O(3)] in the range 10-70 ppb (nl l(-1)) and F(c) was seen in this study. F(c) was primarily driven by stomatal conductance, reactions with surfaces, particles and gases, and not by [O(3)]. On a monthly basis, [O(3)] was always highest in the afternoon while v(d) was typically higher in the morning, resulting in an equal F(c) over the day. Night-time F(c) was more than half of the daytime O(3) flux. The data reveal the importance of emissions of nitric oxide and terpenes as O(3) removal factors in evergreen forest dominated by Norway spruce.

Respiration as the main determinant of carbon balance in European forests

Carbon exchange between the terrestrial biosphere and the atmosphere is one of the key processes that need to be assessed in the context of the Kyoto Protocol. Several studies suggest that the terrestrial biosphere is gaining carbon, but these estimates are obtained primarily by indirect methods, and the factors that control terrestrial carbon exchange, its magnitude and primary locations, are under debate. Here we present data of net ecosystem carbon exchange, collected between 1996 and 1998 from 15 European forests, which confirm that many European forest ecosystems act as carbon sinks. The annual carbon balances range from an uptake of 6.6 tonnes of carbon per hectare per year to a release of nearly 1 t C ha(-1) yr(-1), with a large variability between forests. The data show a significant increase of carbon uptake with decreasing latitude, whereas the gross primary production seems to be largely independent of latitude. Our observations indicate that, in general, ecosystem respiration determines net ecosystem carbon exchange. Also, for an accurate assessment of the carbon balance in a particular forest ecosystem, remote sensing of the normalized difference vegetation index or estimates based on forest inventories may not be sufficient.

A case of cerebral paragonimiasis in Denmark. Case report

A case of cerebral paragonimiasis with severe neurological symptoms is presented. The patient, a 45-year-old woman, recovered completely after resection of a large cyst at the C3 level. The pathogenesis is discussed.

Phenytoin-loading: pharmacokinetic comparison between an intravenous bolus injection and a diluted standard solution

Phenytoin (PHT) is considered a first or second choice in the treatment of status epilepticus that is refractory to benzodiazepines. The use of an intravenous bolus injection of PHT is hazardous due to the risk of cardiac conduction disturbances, dose-dependent side effects in general, as well as the possibility of severe necrotic lesions in case of extravasation. We compared the number and intensity of side effects and serum level profiles of a highly concentrated, non-dilutable bolus (46 mg/ml) of PHT [Fenytoin, DAK] with a dilutable standard solution (1.5 mg/ml) [Phenhydan] administered intravenously in 500 ml saline. Six healthy volunteers received both regiments (9.1 mg/kg). The diluted solution showed a curvilinear saturation curve with a lower concentration maximum (C-max) than the concentrated solution. Lower toxicity of the diluted solution was indicated by a clinical rating of side effects. Based on a higher incidence and degree of side effects following administration of the more concentrated formulation of PHT, compared with the more diluted preparation, we recommend the use of the less concentrated formulation.

Central nervous system reactions to cervical myelography

In a double blind prospective study of side effects to cervical myelography 38 patients were evaluated with neurologic examination, electroencephalography (EEG), brainstem evoked response (BER), somatosensory evoked responses (SSER), and continuous reaction times prior to and at 6 h and 24 h after myelography with either metrizamide or iohexol. A difference in the incidence of side effects (for example headache, dizziness, nausea, and neck pain) to the two different contrast media indicated that the inconveniences related to myelography were not only due to the spinal puncture. A contrast medium effect on the central nervous system varying from one agent to another was present. A high frequency of EEG deteriorations among patients with adverse clinical reactions and on only discrete affection upon BER indicated the reaction to be located to the cerebral cortex. Weakened tendon reflexes and reduced strength in the upper extremities were probably caused by blockade in the motor roots as SSER were normal indicating no affection of the sensory pathways. This hypothesis is in agreement with the fact that the patients were in the prone position in the first phase of the investigation causing the highest concentration of contrast medium around the motor roots and the anterior part of the spinal cord. Difference in metabolic effect may explain differences in side effects of metrizamide and iohexol.

Pharmacokinetic comparison of two carbamazepine slow-release formulations

In a single-blind pharmacokinetic study patients being treated with conventional carbamazepine (CBZ) in a t.i.d. regimen were randomly allocated to identical doses of two CBZ slow-release formulations (Trimonil Retard and Tegretol Retard) administered once daily. Statistical analysis involved the following parameters: AUC, Cmin, Cmax and Fluctuation Index (FI). With regard to Cmin and FI statistically significant differences in favour of Tegretol Retard were observed.

A controlled release form of madopar in parkinsonian patients with advanced disease and marked fluctuations in motor performance

Flucuations in motor performance is a major problem in long-term levodopa treatment of Parkinsonian patients. A slow release preparation of levodopa with benserazide, Madopar HBS, has been developed in an attempt to decrease this problem. Eleven of 22 Parkinsonian patients with advanced disease and marked fluctuations experienced long-lasting benefit with reduction of their fluctuations in motor performance on treatment with Madopar HBS; 11 dropped out within the first 5 months of the trial. This was probably due to lack of experience with the effect of this new slow-release formulation. Nine patients (82%) required an additional dose of standard Madopar, especially in the morning. Significant improvements were found for akinetic phenomenon and dystonic cramps, and with the global evaluation of motor fluctuations. The occurrence of peak dose dyskinesia remained unchanged. No abnormalities in laboratory values were found.

Madopar HBS: slow-release levodopa and benserazide in parkinsonian patients presenting marked fluctuations in symptoms on standard L-dopa treatment

In this open study patients with advanced Parkinson's disease, who experienced pronounced fluctuations in symptoms while on standard L-dopa, were switched from Madopar/Sinemet to Madopar HBS. The dosage was adjusted until optimal response was obtained. The effect was unsatisfactory in 4 cases and side effects intervened in another 2. The remaining 16 patients exhibited substantial and frequently significant improvements with regard to both akinetic and dyskinetic phenomena. L-Dopa dosage was increased in all cases, and addition of standard L-dopa was required in one third of the cases. These benefits continued in the majority of patients.