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Biomedical subjects

A Marcus

Publications and source records attributed to A Marcus.

At least 109 records · Page 6Linked to original sources
PubMed1973

Neuropsychological effects of marijuana.

This study assigned 81 non-naïve subjects, divided into low- and high-dose groups, to four experimental conditions (marijuana/marijuana, marijuana/placebo, placebo/marijuana and placebo/placebo) for two sessions separated by about one week. The low dose was 4.8 mg. Delta(9)-THC followed by 2.4 mg. one hour later. The high dose was 9.1 mg. followed by 4.5 mg. one hour later. A battery of neuropsychological tests was administered.The low dose produced generalized impairment of all mental processes (concept formation, memory, tactile form discrimination and motor function) and the effect was generalized to all modalities. The high dose resulted in more extensive impairment, again generalized.The drug effects noted were explained in terms of generalized impairment of central integrative processes. The effects of marijuana on learning as well as memory were explained in terms of impaired output (recall), but the impairment was transient.

Adult↗
PubMed1973

The neurophysiological basis of the marijuana experience.

Experiments were done with 75 healthy young adults to explore the neurophysiological basis of the acute marijuana intoxication state. Tests included recording the scalp EEG, visual and auditory cerebral evoked-potentials, the CNV, cerebral slow potentials related to certainty of response correctness in auditory discrimination tasks, heart rate, respiration and the galvanic skin response. All variables were recorded over 45 minutes before and 45 minutes after smoking a marijuana cigarette containing either 4.8, 9.1 or less than 0.01 mg. Delta(9)-THC.High doses of marijuana induced a significant decrease in the peak power of the alpha rhythm and an increase in auditory evoked-response latency. The CNV increased in ampiitude after smoking marijuana in low doses and sequential CNVs showed changes consistent with sustained attention but decreased certainty about performance following either low or high dose. Marijuana interfered significantly with performance of the discrimination task itself.

Acoustic Stimulation↗
PubMed1970

Aurintricarboxylic acid and initiation factors of wheat embryo.

In extracts of wheat embryo, aurintricarboxylic acid inhibits attachment of ribosomes to messenger RNA and has little effect on aminoacyl transfer to peptide. This specificity of inhibition allows (i) the demonstration that the initial phase of amino acid incorporation dependent on RNA of tobacco mosaic virus involves an "initiation" reaction between ribosome and messenger RNA which requires two soluble factors, (ii) an assay facilitating purification of the initiation factors, and (iii) the demonstration that these factors are distinct from aminoacyl transfer enzymes.

Amino Acids↗