Anal muscle electromyograms differ in amyotrophic lateral sclerosis and Shy-Drager syndrome

Electromyography (EMG) of anal sphincter muscles was different in patients with amyotrophic lateral sclerosis (ALS) and Shy-Drager syndome. In 30 patients with ALS, EMG of the external sphincter muscle was essentially normal, with no signs of denervation. In eight cases of Shy-Drager syndrome, however, motor unit potentials of the anal sphincter had highly polyphasic forms of long duration and high amplitude. In the Shy-Drager syndrome, there seems to be specific damage of lower motor neurons that innervate the external sphincter muscle of the anus.

The initial positive component of the scalp-recorded somatosensory evoked potential in normal subjects and in patients with neurological disorders

The initial positive component of the scalp-recorded somatosensory evoked potential to median nerve stimulation was studied in 12 patients with sensory impairment for all modalities of the unilateral extremities due to lesions at or above or below the thalamic level, taking the potentials obtained from eight normal subjects as control. In normal subjects, this potential could be easily obtained in ear reference recordings with a peak latency of 12--15 msec. This finding and positive polarity of this potential indicate that the earlobe could be active for this potential. The wide distribution of this potential was different from the subsequent negative-positive diphasic components. In patients with lesions at or above the thalamic level the p15 potential was of normal configuration and latency to stimulation of the affected side, whilst in patients with lesions in the brain stem or in the cervical cord it could not be obtained to stimualtion of the affected side. These findings and short latency of the p15 potential suggest that it may be the result of activity of the medial lemniscal systems from the medulla to the thalamus.

Uptake of 2'-amino-2'-deoxyguanosine by Escherichia coli and its competition by guanosine

The antibacterial activity of a new nucleoside antibiotic, 2'-amino-2'-deoxyguanosine (2AG), is reversed by guanosine and other purine nucleosides. 2AG is apparently taken up by E. coli by a mechanism different from that of guanosine; guanosine inhibits this uptake non-competitively. Insensitive E. coli strains and the resistant mutant obtained from the sensitive strain also took up 2AG.

Mechanism of growth inhibition by 2'-amino-2'-deoxyguanosine in Escherichia coli

The mechanism of inhibition of Escherichia coli by the new nucleoside antibiotic, 2'-amino-2'-deoxyguanosine (2AG), is described. Upon the addition of 2AG, the syntheses of macromolecules continued for 15 minutes. After this lag time, protein synthesis sharply decreased, Rna synthesis slightly decreased, but DNA synthesis was not affected. Tritiated 2AG was readily incorporated into the acid-soluble fraction of cells in the form of the mono-, di- and triphosphates. In the acid-soluble fraction, radioactivity was found only in the RNA fraction. The major part of the radioactivity was found to be guanylate; only 25% existed as the nucleotide of 2AG. In resistant strains of E. coli, there was a lower degree of phosphorylating activity and less incorporation of 2AG into RNA per unit of cell mass increase. These results suggest that 2AG inhibits growth by its incorporation into RNA and the subsequent distrubance of RNA function causing a block in protein synthesis.