[Absence of echoviral RNA sequences in medulla oblongata samples taken from patients who died of ALS].
The role of viral infection in the pathogenesis of ALS has been raised many times in the previous papers. The presence of an enterovirus genome has previously been confirmed using PCR RT and PCR in situ in spinal cord tissue samples taken from patients who died of ALS. Viral genome sequencing has also been used to show 91% and 88% homogeneity with ECHO 6 and 7 viruses, respectively. A year later the same method did not confirm the presence of the virus in spinal cord fragments taken from 30 patients who died of ALS nor in an 18 person control group. The present study was aimed to find persistent ECHO 6 and 7 viral infections in tissue samples taken from patients who died of ALS. RNA was isolated from frozen medulla oblongata samples taken from six patients who died of ALS (hospitalized in the Neurological Clinic CSK AM in the years 2000-2002). The presence of RNA was confirmed using RNA beta-actine. Oligo 2 and 3 as well as pEforward and pErevers primers were used for amplification. All samples returned negative results. In the samples studied no correlation was found between ECHO 6 and 7 viral infections and ALS.