Abnormalities of visual search behaviour in ALS patients detected with event-related brain potentials.

A number of recent reports have emphasized neuropyschological symptoms in ALS, including frontal functions, memory and attention. We investigated visual search behaviour of ALS in two types of tasks: a simple, relatively effortless parallel search task and a more complex attention-demanding serial search task. Behavioural parameters and cognitive event-related potentials (ERP) from 19 scalp channels were obtained from 13 ALS patients and 13 matched controls during task performance. ALS patients showed the same target detection rates as controls in the parallel task but were significantly impaired in the serial task. Performance was slower in the patients than in the controls. This slowing could be attributed to cognitive rather than motor impairments, by inspection of the latency of the P3 component, which was delayed by 120 ms in the patients. In addition, the ERPs in the serial task showed a grossly reduced P3 amplitude, indicating disturbed stimulus evaluation in the patients under these conditions. Changes of an early attention-sensitive ERP component suggest an attention deficit underlying the disturbances in search behaviour.

Recognition memory deficits in amyotrophic lateral sclerosis assessed with event-related brain potentials.

OBJECTIVES: Amyotrophic lateral sclerosis (ALS) has been shown to cause neuropsychological deficits. The present investigation sought to delineate memory deficits by recording cognitive event-related potentials (ERPs). SUBJECTS AND METHODS: Eight ALS patients and 8 matched controls were subjected to a 2-phase recognition memory test. During the first phase words were presented consecutively on a video-screen with one-third of the words being repeated. The subject had to press buttons according to whether a word had been repeated or not. During the second phase (delay 1 h) a second list containing 33% old items from phase 1 and 66% new words was shown with an old/new decision required. RESULTS: ALS patients showed less accurate recognition in the second phase. The ERPs of the controls showed a reliable difference between old and new items in both phases. This difference was nearly absent in the patients in both phases. CONCLUSION: The ERP pattern suggests abnormal memory processes in ALS. The results are compared with data from similar experiments in Huntington's and Alzheimer's disease and are interpreted in terms of an encoding deficit in ALS.

Alteration of early components of the visual evoked potential in amyotrophic lateral sclerosis.

Evoked potentials were recorded in three different visual experiments in 14 patients with amyotrophic lateral sclerosis (ALS) and 14 matched control subjects. Control subjects' evoked potentials (EPs) were characterized by an initial positivity in the 90-140 ms range (P1) at the temporo-occipital site. This component was absent from the group average of the ALS patients as well as the individual patients' EPs. As the P1 is known to emanate from inferior occipito-temporal areas, this finding provides electrophysiological evidence for a cortical involvement in ALS including visual areas.

Poly(A) polymerase in quail oviduct. Changes during estrogen induction.

A nuclear poly(A) polymerase has been isolated from oviducts of immature quails. It could be purified 4300-fold. The enzyme depends specifically on ATP as substrate and requires Mg2+. The most effective primer for the enzyme is a polynucleotide, isolated from oviduct tissue. A poly(A) sequence to a maximum of 60 AMP residues is covalently linked per primer molecule. The poly(A)-rich product of the enzymatic reaction can be annealed to oligo(dT)-cellulose. The purest fraction does not contain any detectable poly(A)-degrading enzyme activity. Only very low activities of RNA polymerase are present. The poly(A polymerase activity in the assay with ATP is reduced by the ATP analogue, beta, lambda-ATP-methylene-diphosphonate. Both K-m and V are lowered. The ATP analogue is incorporated to a smaller extent into the poly(A) sequence, synthesized by the enzyme. Several other analogues of adenine, adenine nucleosides and adenine nucleotides are without effect on the enzymatic reaction. By these properties poly(A) polymerase can be distinguished from RNA polymerases form I and form II, isolated from the same tissue. Actinomycin D and alpha-amanitin failed to inhibit poly(A) polymerase activity. The activity of poly(A) polymerase has been determined during primary stimulation with the estrogen analogue diethylstilbestrol (daily injection for 5 days), after withdrawal of the hormone for 17 days and after secondary stimulation with the hormone analogue. The enzyme activity does not change during primary stimulation, withdrawal of the hormone or secondary stimulation. However the activity of a poly(A) degrading enzyme, localized in the nucleus, is reduced in oviducts from hormone-treated quails.

Poly(adenosine diphosphate-ribose) polymerase in quail oviduct. Changes during estrogen and progesterone induction.

THE ACTIVITIES OF THE FOLLOWING ENZYMES HAVE BEEN DETERMINED IN NUCLEI OF QUAIL OVIDUCTS IN RESPONSE TO EXOGENOUS STIMULATION OF THE BIRDS WITH DIETHYLSTILBESTROL, USED AS AN ESTROGEN ANALOGUE AND PROGESTERONE: DNA dependent DNA polymerase, DNA dependent RNA polymerase I and II and poly(adenosine diphosphate-ribose) [=poly(ADP-Rib)] polymerase.During primary stimulation with the estrogen analogue the activities of the four DNA dependent polymerases increase to about the same degree. Upon withdrawal of the hormones the levels of the enzymes drop to values known from nuclei from unstimulated quail oviducts. The secondary stimulation with the estrogen analogue causes a significant increase only of the RNA polymerase II. The in vivo induction of avidin by progesterone in oviduct mucosa cells from quails, during the period of primary estrogen stimulation, is accompanied by an increase of RNA polymerase II activity and a marked decrease of poly(ADP-Rib) polymerase activity. The activities of RNA polymerase I and of poly(ADP-Rib) polymerase are not affected significantly by an exogenous administration of progesterone.