Cytogenetic investigation of occupational exposure to epichlorohydrin.

Cytogenetic evaluation of peripheral lymphocytes from 93 workers currently exposed to epichlorohydrin has revealed an increase in aberration rates as compared to that of a 75-person group seen for preemployment examination. Statistically significant differences were found in the distribution of individuals with chromatid breaks, chromosome breaks, severely damaged cells, and total abnormal cells. These results confirm the observations of Kucerova et al.

Dominant lethality in frog embryos after paternal treatment with triethylenemelamine: cytogenetics, morphology, and swimming capability.

Male frogs (Rana pipiens) were injected intraperitoneally with triethylenemelamine (TEM). The injected males were held for seven days to permit TEM interaction with sperm. The TEM-treated males were then spermiated with human chorionic gonadotropin (HCG) and the ova of normal females were inseminated with the sperm.

Vinyl chloride cytogenetics.

This report presents cytogenetic findings from a group of 209 workers employed for up to 28 years in the manufacture of vinyl chloride monomer at the Texas Division of Dow Chemical U.S.A.

A short-term culture method for the preparation of chromosome spreads from Rana pipiens.

Chromosomes suitable for karyotyping were produced from short-term cultures of cells from embryonic northern leopard frogs, Rana pipiens, at various growth stages. Embryos were minced in a trypsin solution. The tissue fragments were subsequently cultured in an electrolytic solution containing fetal calf serum and Colcemid.

Fertilization and development of frog eggs after repeated spermiation induced by human chorionic gonadotropin.

Sperm released into the urine of adult male frogs, Rana pipiens, after intraperitoneal injection of human chorionic gonadotropin, were used to fertilize freshly ovulated eggs. Repeated spermiations from the same animal were induced with repeated injections of the hormone at intervals of four to 11 days. Individual frogs were induced to spermiate up to four times, with fertile sperm ensuing each time.

alpha-and beta-Globin complementary deoxyribonucleic acids of human and rabbit. Specificity of hybridization.

The specificity of hybridization was compared between the human and rabbit alpha and beta-globin complementary DNAs (cDNAs) and the corresponding alpha and beta-globin messenger RNAs (mRNAs). The globin chain-specific mRNAs of rabbit were prepared from polysomes incubated with O-methylthreonine (alpha and beta) or from postribosomal supernatant (alpha). Enrichment for either the alpha- or beta-globin mRNA was demonstrated by cell-free protein synthesis and by RNA-cDNA hybridization.

Hemoglobin synthesis in somatic cell hybrids: globin gene expression in hybrids between mouse erythroleukemia and human marrow cells or fibroblasts.

Somatic cell hybrids were generated by fusion of mouse erythroleukemia cells either to mouse L cells (B82), human fibroblasts (W1-18 VA2), or human marrow fractions enriched in erythroblasts. The hybrid cells were examined for globin gene expression by benzidine staining to detect cytoplasmic hemoglobin, and by molecular hybridization of cellular RNA to globin complementary DNA (cDNA) to detect globin messenger RNA (MRNA). The fibroblast (human or mouse) times erythroleukemia cell hybrids grown in monolayer retained most of the chromosomes of each parent.

Cell-free transcription of mammalian chromatin: transcription of globin messenger RNA sequences from bone-marrow chromatin with mammalian RNA polymerase.

A mammalian cell-free transcriptional system was developed in which mammalian RNA polymerase synthesizes globin messenger RNA sequences from bone-marrow chromatin. The messenger RNA sequences are detected by measurement of the ability of the transcribed RNA to hybridize with globin complementary DNA. The globin complementary DNA is synthesized by the enzyme from avian myeloblastosis virus, RNA-directed DNA polymerase, with purified globin messenger RNA as template.

Translation of exogenous messenger RNA for hemoglobin on reticulocyte and liver ribosomes.

The ribosome and initiation factor requirements for translation of rabbit-reticulocyte hemoglobin mRNA on rabbit reticulocyte ribosomes, reticulocyte ribosomal subunits, and liver ribosomes have been studied. Excellent synthesis of globin chains from exogenous mRNA in the fractionated cell-free system has been achieved. There is a near absolute requirement for each of the initiation factors, M(1), M(2), and M(3) (as well as for the supernatant proteins) for the translation of exogenous mRNA.