Profiles of gene expression changes in L5178Y mouse lymphoma cells treated with methyl methanesulfonate and sodium chloride.

Treatment of cells with genotoxic chemicals is expected to set into motion a series of events including gene expression changes to cope with the damage. We have investigated gene expression changes in L5178Y TK(+/-) mouse lymphoma cells in culture following treatment with methyl methanesulfonate (MMS), a direct acting genotoxin, and sodium chloride (NaCl), which induces mutations in these cells through indirect mechanisms at high concentrations. The mouse lymphoma cells were treated for 4 or 24 h and the cells were harvested for RNA isolation at the end of the treatment.

Evaluation of the potential of triethanolamine to alter hepatic choline levels in female B6C3F1 mice.

Triethanolamine (TEA), a widely used nongenotoxic alcohol-amine, has recently been reported to cause an increased incidence of liver tumors in female B6C3F1 mice, but not in males nor in Fischer 344 rats. Choline deficiency induces liver cancer in rodents, and TEA could compete with choline uptake into tissues. The potential of TEA to cause choline deficiency in the liver of these mice as a mode of tumorigenesis was investigated.

An in vitro screening paradigm for extracts of whole foods for detection of potential toxicants.

The application of organic, conventional and biotechnology techniques can alter the intrinsic levels of natural toxicants in crop foods and methods are needed to screen for unexpected changes in toxicant levels. We evaluated crude, aqueous preparations of 37 foods purchased from a local market in a battery of four in vitro mammalian toxicity screens. The foods were evaluated in one or more of the following tests: (1) cytotoxicity (37 foods) and (2) chromosomal aberration test (nine foods), both in Chinese hamster ovary cells, (3) limb bud micromass assay (nine foods) using 11-day old CD-1 mouse embryos and (4) estrogenicity (MCF-7 cells transfected with estrogen receptor and lucerifase reporter constructs, 12 foods).

Evaluation of the genotoxicity of 2,4-dichlorophenoxyacetic acid and its derivatives in mammalian cell cultures.

2,4-dichlorophenoxyacetic acid and its derivatives (collectively known as 2,4-D) are herbicides used to control a wide variety of broadleaf and woody plants. The genetic toxicity of an ester (2,4-D 2-butoxyethylester) and two salts (2,4-D isopropylamine and 2,4-D triisopropanolamine) was investigated in cultured mammalian cells. The end points used were the induction of chromosomal aberrations in primary cultures of rat lymphocytes and forward mutations at the HGPRT locus of Chinese hamster ovary cells.

Clastogenicity of isoamylene oxide to rat lymphocytes in culture.

The mutagenic activity of the aliphatic epoxide isoamylene oxide (2-methyl-2,3-epoxybutane) is not readily detectable in the standard Ames test. In this study, the clastogenic potential of isoamylene oxide was evaluated using an in vitro mammalian cell culture system. Approximately 48 h after establishing primary cultures of rat lymphocyte cultures, the cells were treated for 4 h with various concentrations of isoamylene oxide (50, 166.

Evaluation of the genetic toxicity of the organophosphate insecticide chlorpyrifos.

The genetic toxicity of chlorpyrifos [O,O,-diethyl-O-(3,5,6-trichloro-2- pyridinyl)phosphorothioate, C.A.S.

Chromosomal aberrations in bone marrow and peripheral blood cells from the same rats.

Spontaneous cytogenetic aberrations were analyzed in bone-marrow cells and cultured peripheral lymphocytes from the same animals. No significant differences in the total number of cells with aberrations or total aberrations were detected between the bone-marrow cells and cultured lymphocytes. It was concluded that short-term culture does not contribute significantly to in vivo aberration yield within the experimental conditions used.

Utilization of rat lymphocytes for the in vitro chromosomal aberration assay.

In vitro cytogenetic assays are widely conducted to assess the mutagenic potential of chemicals. Chinese hamster ovary (CHO) cells or human lymphocytes are often used for these assays; however, these cell types have certain limitations. In order to evaluate an alternate cell system, cultured rat lymphocytes were treated for 4 h at 48 h of incubation with a variety of direct- and indirect-acting clastogens in the presence or absence of an exogenous mammalian activation system.

Assessment of cell cycle duration on the incidence of sister chromatid exchanges in somatic and spermatogonial cells of the rat.

In order to examine the influence of the length of cell cycle on the incidence of sister chromatid exchanges (SCEs), average generation times and SCEs were studied in the presence of bromodeoxyuridine from spontaneously dividing rat lymph node, bone marrow, spleen, and spermatogonial cells. Average generation time differences among the three somatic cell types (lymph node, 7.6 h; bone marrow, 12.

Effect of food and water deprivation on the parameters of the mouse bone marrow micronucleus test.

This study reports the influence of acute starvation on spontaneous and cyclophosphamide (CP) induced micronucleus (MN) frequencies in the bone marrow polychromatic erythrocytes (PCE) of CD-1 mice. Groups of mice (5/sex) were deprived of either food alone or food and water for 0, 24, 48 and 72 h prior to sacrifice. Although there was no evidence of a significant increase in MN-PCE frequencies among the starved groups, a significant depressant effect of starvation on erythropoietic activity was observed.

Cytogenetic variability of lymphocytes from phenotypically normal men: influence of age, smoking, season, and sample storage.

A cytogenetic study was conducted on cultured lymphocytes from a group of 60 male volunteers to determine the baseline of chromosomal aberrations in nonchemical workers. Only males were included in the study to avoid any sex effects on the results. Blood samples were collected from each man every 13 w (quarterly) over a period of 12 m.

Analyses for in vitro growth conditions, cytokinetics, and sister chromatid exchanges in lymphocytes cultured from the Sprague-Dawley rat.

Peripheral blood samples from Sprague-Dawley rats gave successful lymphocyte growth in GIBCO: 1A, RPMI 1640, and Eagle's minimum essential medium (MEM) culture media. Various growth conditions, cytokinetics, and sister chromatic exchange (SCE) induction were studied using reconstituted GIBCO 1A only. Neither methoxyflurane anesthesia of the rats before sampling nor washing of the cells with phosphate buffered saline affected the mitotic index.

Analysis of sister chromatid exchanges in lymphocytes cultured from 71 healthy men.

Sister chromatid exchanges (SCE) were analyzed in peripheral blood lymphocytes from a select group of 71 healthy men, 56 nonsmokers and 15 cigarette smokers. In addition to estimating baseline SCE, data were examined to seek relationships of SCE frequencies to age and smoking. The baseline value of 7.

Supernumerary chromosomal elements in lymphocytes cultured from phenotypically normal human adult males.

In a group of phenotypically normal men there were approximately 0.24% of metaphase lymphocytes with extra chromosomal elements along with the regular 46 chromosomes. They ranged in size from small acrocentric-acentric elements to elements longer than any chromosome arm.

The incidence of spontaneous cytogenetic aberrations in lymphocytes cultured from normal humans for 48 and 72 h.

Spontaneously occurring cytogenetic aberrations were compared in 48- and 72-h human lymphocyte cultures from a group of 20 normal male volunteers. Mitotic indices for both cultures times were also evaluated. BUdR (5-bromo, 2-deoxyuridine) labelled metaphases from three men were utilized to determine the cell cycle kinetics in the medium used.

Evaluation of the effect of food deprivation on micronucleus test results.

High doses of a test chemical sometimes affect the food consumption of the treated animals even to the point of starvation. The effect of such a non-specific toxicological stress on the bone marrow micronucleus test was investigated in male and female Sprague-Dawley rats. A 42-h starvation had a noticeable effect on the ratio of polychromatic to normochromatic erythrocytes (PCE and NCE); the values in the starved animals were approx.

Evaluation of culture media for effects on cell cycle kinetics and incidence of chromosomal aberrations in human blood cells.

Peripheral blood samples from 17 apparently healthy male volunteers were set up in duplicate cultures using three commercially available media: Eagle's MEM, RPMI 1640, and TC 199. BUdR (5-bromo,2-deoxyuridine) (10 micrograms/mL) was added to one of the cultures from each person in each medium after 24 h of culture initiation. All cultures were harvested at 72 h of incubation in the presence of colcemid.

In vivo cytogenetic study in rats maintained for eight days on diets containing probucol.

Probucol (4,4'-(isopropylidenedithio)bis(2,6-di-t-butylphenol], a cholesterol-lowering drug, was evaluated for cytogenetic toxicity in the bone-marrow cells of Sprague-Dawley rats. Male and female rats were fed diets containing 0, 200, 400, or 800 mg/kg body weight/day for 8 consecutive days. Animals treated with trimethylphosphate served as positive controls.

A note on the utility of Fischer-344 rat in the micronucleus test.

Bone marrow smears from Fischer-344 rats possessed such a high incidence of basophilic granules that accurate detection of micronucleated erythrocytes was not possible. In contrast, preparations from Sprague-Dawley rats had far fewer such granules, so that the micronucleated marrow cells were clearly visualized and counted. The difference in the incidence of basophilic granules was attributed to strain differences in mast cell population size.

Cytogenetic evaluation of bone marrow cells from rats exposed to styrene vapor for one year.

This report presents the cytogenetic findings in bone marrow cells of rats exposed to styrene vapor. Male and female Sprague-Dawley rats were exposed to 0,600 and 1000 ppm of styrene vapor by inhalation 6 hr per day, 5 days a week, for a period of one yr. Blind scoring of metaphase spreads prepared from bone marrow cells collected at the end of the last exposure revealed that neither the 600 ppm nor the 1000 ppm exposures to styrene vapor produced an incidence of chromosomal anomalies higher than those occurring spontaneously.

Hematologic and myelogenous effects of inhaled benzene in the pig and the rat.

Four groups of 4 domestic pigs were exposed to 0, 20, 100, and 500 ppm benzene vapor 6 h/d, 5 d/wk, for 3 wk. Two groups of 10 rats were exposed to 0 and 500 ppm: the exposed rats for 6 h/d, 5 d/wk, for 3 wk, the nonexposed rats for 6 h/d, 5 d. Rats were killed within 72 h after exposure; values for pigs were obtained shortly after exposure and on final examination at 4-16 wk after exposure.