Study of spontaneous recurrent seizures and morphological alterations after status epilepticus induced by intrahippocampal injection of pilocarpine

Epileptic seizures are clinical manifestations of neuronal discharges characterized by hyperexcitability and/or hypersynchrony in the cortex and other subcortical regions. The pilocarpine (PILO) model of epilepsy mimics temporal lobe epilepsy (TLE) in humans. In the present study, we used a more selective approach: microinjection of PILO into the hilus of the dentate gyrus (H-PILO). Our main goal was to evaluate the behavioral and morphological alterations present in this model of TLE. Seventy-six percent of all animals receiving H-PILO injections had continuous seizures called status epilepticus (SE). A typical pattern of evolution of limbic seizures during the SE with a latency of 29.3 ± 16.3 minutes was observed using an analysis of behavioral sequences. During the subsequent 30 days, 71% of all animals exhibited spontaneous recurrent seizures (SRSs) during a daily 8-hour videotaping session. These SRSs had a very conspicuous and characteristic pattern detected by behavioral sequences or neuroethiological analysis. Only the animals that had SE showed positive Neo-Timm staining in the inner molecular layer of the dentate gyrus (sprouting) and reduced cell density in Ammon's horn pyramidal cell subfield CA1. However, no correlation between the intensity of sprouting and the mean number and total number of SRSs was found. Additionally, using Fluoro-Jade staining, we observed neurodegeneration in the hilus and pyramidal cell subfields CA3 and CA1 24 hours after SE. These data indicate that H-PILO is a reliable, selective, efficient, low-mortality model that mimics the acute and chronic behavioral and morphological aspects of TLE.

Detection of adulteration of pasteurised milk with whey by determination of the casein-bound phosphorus and protein nitrogen content

A new method to detect the adulteration of pasteurised milk with whey is described. The method is based on the determination of casein-bound phosphorus (Pcas) and the protein nitrogen content in milk. By using a mean Pcas content (0.85 g P/100 g casein), a Kjeldahl factor of 6.34 and protein N, the relative casein-N content (casein N/protein N x 100) can be estimated. Over a period of one year the variation in the phosphorus factor of dried skimmed milk samples amounted to 2.9%. In order to calculate the percentage of added whey, a standard curve has been prepared in which the relative casein content is plotted against the corresponding whey percentage. The results of 26 analyses on genuine pasteurised milk (Pcas = 21.7 mg/100 ml; casein N/protein N = 80.9%) and on 25 whey samples were used for the standard curve. In laboratory-made blends of pasteurised milk and cheese whey (5%, 10%, 20% and 30%), the estimated percentage of whey varied between -1.2% and +2.9% from the actual value. The analysis of nine samples from the Brazilian market showed that four samples were clearly adulterated with cheese whey. Sweet and/or acid whey addition will be detected by the proposed method.