The relationship between the contingent negative variation and the reaction time under prolonged experimental conditions

Vertex, frontal and temporal CNVs were recorded during the S₁-S₂ interval of a prolonged simple reaction time task and correlated with RTs obtained. The data were measured in two ways: objectively, by measuring the CNV by means of a computer; and less objectively, by measuring the CNV by means of a ruler from the CAT-averaged graphs in the ‘traditional’ manner. Several amplitude measures were taken. Also the vertex, frontal and temporal evoked potentials to S₁ and S₂ were measured. No systematic relationship between different CNV measures and the RT could be observed. Whereas the amplitudes of the evoked potentials clearly habituated during the experimental session, the amplitudes of the CNV remained at their original values.     

Tonic dystonia: an uncommon complication of reflex sympathetic dystrophy syndrome. A review of five cases

Tonic dystonia is an underrecognized complication of reflex sympathetic dystrophy syndrome (RSDS) characterized by an increase in muscle tone at the site of injury. Case-reports.- We describe five cases of tonic dystonia complicating RSDS of the lower extremity. There were four women and one man, with a mean age of 52 years. In addition to the typical features of RSDS, the patients had fixed equinovarus of the foot with hyperextension or hyperflexion of the great toe. In two patients, examination after spinal anesthesia showed that the deformity was reducible. Spontaneous resolution of the dystonia occurred in one patient. Another patient failed to experience meaningful improvement after a motor block followed by botulinic toxin injections. In two patients, the same treatment was followed by a slight improvement. Treatment options are still being evaluated in the last patient. Discussion.- Tonic dystonia is an underrecognized complication of RSDS that often develops after a minor injury yet causes prolonged pain and disability. Spread of the dystonia to other sites is not infrequent. The underlying mechanisms remain unclear but may involve dysfunction of the central or peripheral nervous system or psychogenic factors. Suggested treatments include motor block, intrathecal baclofen, sympathetic block, and sympathectomy. However, none of these treatments has been proved effective. Conclusion.- The five cases described here provide useful information on RSDS-associated tonic dystonia, a condition that runs a protracted course and remains difficult to manage.     

Distribution of radioactivity following oral administration of carcinogenic 14CH3-labelled nitrosocarbaryl in the rat

After a single intragastric administration of ¹⁴C-labelled carcinogenic nitrosocarbaryl, a nitrosated pesticide, the distribution of radioactivity was investigated in the blood and a number of organs in male rats. The animals received 0.25 mg/kg of labelled nitrosamine and were killed following administration at timed intervals between 0.5 h and 24 h.Our results show that the greatest amount of the ¹⁴CH₃-group was associated with the forestomach, tumor-susceptible tissue; the level of radioactivity is noteworthy but less important in the glandular stomach. There are also sites of radioactivity accumulation mainly in the liver. Moreover, [¹⁴C]nitrosocarbaryl was revealed in the blood suggesting that nitrosamine itself rapidly (0.5 h) crosses the intestinal barrier and in a significant quantity (13%). These facts constitute a potential carcinogenic risk.