Maimon M. Cohen

In vivo and in vitro chromosomal damage induced by LSD-25.

THE induction of chromosomal aberrations by exogenous agents, such as viruses, radiation and chemicals, is an area of active cytogenetic investigation.1 Recently, the psychotomimetic hallucinogen, ...

TWO XY SIBLINGS WITH GONADAL DYSGENESIS AND A FEMALE PHENOTYPE.

ANOMALOUS sexual development has been attributed to hormonal imbalance, chromosomal aberration and developmental disturbance of unknown etiology as well as genetic causes such as testicular feminiz...

The Effect of LSD-25 on the Chromosomes of Children Exposed in Utero

Extract: This paper reports the cytogenetic investigation of nine children exposed to LSD-25 in utero, four children of other LSD users not exposed in utero, the mothers of these children, and six additional adults taking the drug. In comparison with matched controls, significantly elevated frequencies of chromosomal damage were observed in all the individuals exposed. The frequencies of aberrations, however, were markedly reduced in those children not exposed in utero. Eight structural rearrangements were observed, six dicentric chromosomes and two quadriradial formations, among those individuals exposed to the drug, but none was observed in the controls. In spite of obvious chromosomal aberrations, all of the individuals in this study were apparently healthy and showed no obvious birth defects.Speculation: The significance of chromosomal damage produced in utero by pharmacologic agents and observed in the circulating lymphocytes of exposed infants and children remains controversial. Analogies have been drawn which suggest possible consequences of these lesions. The present study documents chromosomal damage in somatic cells of patients lacking any physical abnormality and reemphasizes the necessity for defining the extent to which chromosomal imbalance can be tolerated without phenotypic deviation. One can only speculate on possible biological events were such agents to affect the chromosomes of spermatagonial cells and thus yield defective gamates. Were this to eventuate, drugs with chromosome-breaking potential could act as powerful mutagens and have effects persisting into subsequent generations.

Specific effects of viruses and antimetabolites on mammalian chromosomes

SummaryThe apparent localization of chromosomal breakage and other specific effects of viruses and antimetabolites is reviewed. These agents all manifest their effects in the heterochromatic regions of the chromosomes, e.g. the paracentric regions and secondary constrictions. Those cases in which the chemical mode of action of the agent is well elucidated and in which the agent exhibits a specific affinity for a given chromosomal segment may yield information concerning the structure of the chromosome. The significance of this approach to the mapping of chromosome structure and function is discussed. Since all the agents affect mainly heterochromatic regions we must consider the interpretation that the specificity of breakage at localized segments is a property of the chromosome itself rather than of the agent.

Nucleic Acid Synthesis in Various Organs of Developing Human Fetuses

Extract: In order to establish the mode of differentiation in various developing organs, the patterns of nucleic acid synthesis were studied in 14 human fetuses. The gestational age ranged from 8–15 weeks. Incorporation of radioactive precursors into DNA and RNA of cells in liver, kidney, heart, skin, spleen, lung, and brain were measured by autoradiography. Unique patterns of nucleic acid synthesis were observed in each of seven organs studied. The curves of DNA and RNA synthesis were “mirror images” of each other, which indicated organ-specific periodicity of nucleic acid synthesis.Speculation: The findings of this study indicate periodicity and unique patterns of nucleic acid synthesis in developing organs of human fetuses at various gestational ages. It is possible that physical and chemical substances affecting nucleic acid synthesis of a particular organ may be most deleterious during this period.