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PubMed1996

Lens epithelial cell mRNA. III. Elevated expression of macrophage migration inhibitory factor mRNA in galactose cataracts.

A lens epithelial (LE) cell cDNA clone, designated Clone 156, was isolated from a mature rat LE cDNA library by methods of subtractive hybridization. The cDNA sequence of Clone 156 was 521 nucleotides in length, excluding the poly(T)-tail, and it encoded an open reading frame of 115 amino acids. The translated protein shared extensive sequence similarities with macrophage migration inhibitory factor (MIF) from mouse lens and human T-cell lymphocytes. Northern blot hybridization showed that rat lens MIF mRNA is about 500 nucleotides in length and that its expression in mature rat lens is relatively low in comparison with that in other rat tissues. The expression of MIF mRNA in LE of normal rats and of rats treated by feeding a diet of 50% (w/w) galactose was studied by quantitative RT-PCR. The results showed that the expression of MIF mRNA in a 20-day galactosemic rat LE increased twelvefold as compared to that found in control LE. From the results of this study and from what we know about the locale of epithelial cell differentiation in mature rat lenses, it is being proposed that the increase in abundance of MIF mRNA in the cataractous rat lens is correlated with the enhanced proliferation of the undifferentiated epithelial cells.

Animals↗
PubMed2006

Reversal of neuronal migration in a mouse model of fetal alcohol syndrome by controlling second-messenger signalings.

The brains of fetal alcohol syndrome patients exhibit impaired neuronal migration, but little is known about the mechanisms underlying this abnormality. Here we show that Ca2+ signaling and cyclic nucleotide signaling are the central targets of alcohol action in neuronal cell migration. Acute administration of ethanol reduced the frequency of transient Ca2+ elevations in migrating neurons and cGMP levels and increased cAMP levels. Experimental manipulations of these second-messenger pathways, through stimulating Ca2+ and cGMP signaling or inhibiting cAMP signaling, completely reversed the action of ethanol on neuronal migration in vitro as well as in vivo. Each second messenger has multiple but distinct downstream targets, including Ca2+/calmodulin-dependent protein kinase II, calcineurin, protein phosphatase 1, Rho GTPase, mitogen-activated protein kinase, and phosphoinositide 3-kinase. These results demonstrate that the aberrant migration of immature neurons in the fetal brain caused by maternal alcohol consumption may be corrected by controlling the activity of these second-messenger pathways.

Animals↗
PubMed2026

Impact of NR4A3 on wound healing in chronic venous ulcers and its association with the PI3K/Akt signaling pathway.

BACKGROUND: To investigate the role of NR4A3 in chronic venous ulcer (VU) wound healing and to explore its potential regulatory mechanism involving the PI3K/Akt pathway. METHODS: Differential expression and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed using the GSE174661 dataset. DEGs were filtered by |log2FC| > 1 and adjusted P < 0.05, with KEGG significance set at P < 0.05. NR4A3 was identified as the core gene. NR4A3 knockdown and overexpression were established in HaCaT cells to evaluate proliferation, migration, and inflammatory cytokines. TNF-&#x3b1; was used to mimic the inflammatory microenvironment. Western blotting assessed phosphorylation of GSK3&#x3b2;, mTOR, PI3K, and Akt. PI3K/Akt agonist 740Y-P and inhibitor LY294002 were used in rescue experiments. RESULTS: Bioinformatic analysis revealed that NR4A3 expression was markedly downregulated in chronic venous ulcer (VU) tissues relative to normal skin and ordinary acute wound tissues. Differentially expressed genes were significantly enriched in the PI3K/Akt signaling pathway. TNF-&#x3b1; stimulation significantly upregulated NR4A3 expression and increased phosphorylation of GSK3&#x3b2; and mTOR in HaCaT cells. In cultured HaCaT keratinocytes, NR4A3 knockdown suppressed cell proliferation and invasion, enhanced cell migration, and elevated the expression and secretion of pro-inflammatory cytokines (IL-6, IL-8, CXCL5), accompanied by reduced phosphorylation of PI3K and Akt. Conversely, NR4A3 overexpression promoted cell proliferation and invasion, restrained migration, and dampened inflammatory responses, while increasing PI3K/Akt phosphorylation. Treatment with the PI3K/Akt agonist 740Y-P partially rescued the impaired proliferation, aberrant migration, and excessive inflammation caused by NR4A3 silencing, whereas PI3K/Akt inhibitor LY294002 aggravated pathway suppression. These findings suggest that NR4A3-associated changes in keratinocyte functions and inflammatory reactions are functionally linked to PI3K/Akt pathway activity, and inflammatory stimulation activates GSK3&#x3b2;/mTOR signaling accompanied by compensatory NR4A3 upregulation. CONCLUSION: These findings suggest that NR4A3 is associated with keratinocyte behavior and inflammatory responses via the PI3K/Akt pathway, potentially affecting chronic VU progression and healing. Reduced NR4A3 may impair wound repair through inflammation and abnormal cell migration, while TNF-&#x3b1; induces compensatory NR4A3 elevation.

NR4A3↗
PubMed1992

Antagonistic effects of TGF-beta 1 and MSF on fibroblast migration and hyaluronic acid synthesis. Possible implications for dermal wound healing.

The migration of adult skin fibroblasts into three-dimensional collagen gel matrices is differentially affected by cell density, with subconfluent cells displaying a significantly elevated level of migration compared to confluent ones. Fetal fibroblasts differ from adult cells in that they display an elevated level of migration at both subconfluent and confluent cell densities. We have previously reported that this difference in behaviour results from the secretion by fetal fibroblasts of a 'migration stimulating factor' (MSF) which is not made by their normal adult counterparts, and that MSF appears to act by stimulating the synthesis of hyaluronic acid (HA). Data presented in this communication indicate that (a) MSF specifically stimulates the synthesis of high molecular weight species of HA, (b) TGF-beta 1 inhibits the elevated migration of adult fibroblasts plated at subconfluent cell density, (c) under these conditions, TGF-beta 1 induces a parallel decrease in the synthesis of high molecular weight HA and increase in the synthesis of low molecular weight HA, (d) TGF-beta 1 is a potent antagonist of MSF, effectively blocking its stimulation of cell migration and synthesis of high molecular weight HA, and (e) the inhibition of fibroblast migration by TGF-beta 1 does not appear to be a chemotactic response dependent upon the existence of a concentration gradient of the cytokine. Our observations regarding the inhibitory effects of TGF-beta 1 on fibroblast migration into 3D collagen gels stand in marked contrast to various published reports indicating that this cytokine stimulates the migration of human skin fibroblasts through the pores of polycarbonate filters as used in modified Boyden chamber assays; this discrepancy underscores the importance of the substratum in modulating cellular response to cytokines. Our results are discussed in terms of the possible combined contribution of MSF and TGF-beta 1 to wound healing.

Cell Movement↗
PubMed2004

Barhl1 regulates migration and survival of cerebellar granule cells by controlling expression of the neurotrophin-3 gene.

The neurons generated at the germinal rhombic lip undergo long distance migration along divergent pathways to settle in widely dispersed locations within the hindbrain, giving rise to cerebellar granule cells and precerebellar nuclei. Neurotrophin-3 (NT-3) signaling has been shown to be required for proper migration and survival of cerebellar granule cells. The molecular bases that govern NT-3 expression within the cerebellum, however, remain unknown at present. Here we report that, during early mouse neurogenesis, the Barhl1 homeobox gene is highly expressed by the rhombic lip and rhombic lip-derived migratory neurons. Its expression is later restricted to cerebellar granule cells and precerebellar neurons extending mossy fibers, two groups of neurons that synaptically connect in the adult cerebellar system. Loss of Barhl1 function causes cerebellar phenotypes with a striking similarity to those of NT-3 conditional null mice, which include attenuated cerebellar foliation as well as defective radial migration and increased apoptotic death of granule cells. Correlating with these defects, we find that NT-3 expression is dramatically downregulated in granule cells of the posterior lobe of Barhl1(-)/- cerebella. Moreover, in the precerebellar system of Barhl1(-/-) mice, all five nuclei that project mossy fibers fail to form correctly because of aberrant neuronal migration and elevated apoptosis. These results suggest that Barhl1 plays an essential role in the migration and survival of cerebellar granule cells and precerebellar neurons and functionally link Barhl1 to the NT-3 signaling pathway during cerebellar development.

Animals↗
PubMed1998

Exercise-induced DNA effects in human leukocytes are not accompanied by increased formation of 8-hydroxy-2'-deoxyguanosine or induction of micronuclei.

The present study examined the effects of a short-distance triathlon on the induction of DNA effects in peripheral leukocytes, urinary excretion of oxidized DNA bases, and frequency of micronuclei in lymphocytes of human volunteers. Induction of DNA effects was measured as increased DNA migration using the alkaline comet assay. Increased DNA migration was found in leukocytes of all individuals at different time points after exercise and revealed a biphasic pattern. Twenty-four hours postexercise, elevated DNA migration was found, whereas lower values were detected 48 h after exercise. Seventy-two hours postexercise, the maximum increase in DNA migration was found and baseline values were still elevated after 120 h. A modified protocol of the comet assay for the detection of oxidized DNA bases revealed no differences in leukocytes before and directly after the triathlon. Urinary excretion of 8-hydroxy-2'-deoxyguanosine remained unaltered during the 5 consecutive days sampled. No differences were found in the micronucleus-frequency in lymphocytes before or 48 and 96 h after exercise. Our data suggest that DNA effects detected with the comet assay in leukocytes of humans after exercise are secondary effects that do not originate from oxidized DNA bases and do not result in chromosome damage.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1984

Changes in serum concentrations of steroid hormones, thyroxine, and vitellogenin during spawning migration the chum salmon, Oncorhynchus keta.

Changes in serum concentrations of various steroid hormones (estradiol-17 beta, androgens, 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17 alpha,20 beta-diOHprog], thyroxine, and vitellogenin during the spawning migration (from the coastal sea to the spawning ground) of male and female chum salmon (Oncorhynchus keta) were investigated. In females, estradiol-17 beta levels were high during the early phases of the migration (sea and prespawning period), but significantly decreased in fish at the time of the spawning period (oocyte maturation and ovulation). The changes in estradiol-17 beta levels coincided with those of of serum vitellogenin levels. High levels of androgens were observed throughout the sampling period. Serum 17 alpha, 20 beta-diOHprog levels were extremely low during the early phases of spawning migration, but elevated dramatically in mature or ovulating females. In males, serum concentrations of androgens were high during the early phases of the migration, but sharply declined around the time of the spawning period (spermiation). Similar to females during final maturation, the serum levels of 17 alpha,20 beta-diOHprog in males rapidly increased during spermiation, although the magnitude of the elevation in males was smaller than in females. Serum thyroxine levels were highest both in females and males collected in the coastal sea, and the levels decreased during the spawning migration. These findings are discussed in relation to anadromous migration and sexual maturation of chum salmon.

Animals↗
PubMed2001

Macrophage migration inhibitory factor (mif) transcription is significantly elevated in Caenorhabditis elegans dauer larvae.

Macrophage migration inhibitory factor (MIF) from vertebrate species is a molecule that exerts a wide-range of effects in inflammatory responses, cell activation and cell differentiation. Several species of parasitic nematodes have been shown to express genes encoding orthologues of the mammalian MIF that appear to play a key role in immune evasion by modifying the activity of host cells. In addition, MIF accumulates in nematode somatic cells where its role has not yet been defined. In order to identify the role that MIF plays in the cell biology of nematodes, we have characterized the members of the mif gene family in the free-living species Caenorhabditis elegans. Unlike the single mif gene found in humans and mice, C. elegans expresses four distinct mif genes: Ce-mif-1, Ce-mif-2, Ce-mif-3 and Ce-mif-4. The Ce-MIF proteins are between 15-30% identical to each other, 34-38% identical to the MIFs from the parasitic nematode Brugia malayi, and 22-35% identical to mammalian MIFs. The transcription of Ce-mif-2 and Ce-mif-3, but not Ce-mif-1, was upregulated >100-fold compared to L2 levels when the worms entered the dauer stage. The transcription levels of Ce-mif-2 and Ce-mif-3 fell to near baseline a few hours after exit from dauer. Ce-MIF/GFP transgenic animals and immunostaining were used to demonstrate that the main sites of MIF production are in the hypodermis, body wall muscles and in the nuclei of developing embryos. The results suggest a role for C. elegans MIF in cellular maintenance during periods of adverse conditions that lead to developmental arrest.

Amino Acid Sequence↗
PubMed1997

Differential response of fetal and adult fibroblasts to cytokines: cell migration and hyaluronan synthesis.

Previous studies have indicated that fetal skin fibroblasts display an elevated level of migratory activity compared to adult cells and that this may result from inherent differences in the production of hyaluronan (HA) by these cells. Data presented in this communication indicate that the elevated level of fetal fibroblast migration into 3D-collagen gels and HA synthesis by these cells were not affected by epidermal growth factor (EGF), platelet-derived growth factor (PDGF), acidic fibroblast growth factor (aFGF) or basic fibroblast growth factor (bFGF). In contrast, both cell migration and HA synthesis by fetal fibroblasts were inhibited by transforming growth factor-betal (TGF-beta1). Adult fibroblasts responded to these cytokines in a distinct fashion: i.e. cell migration and HA synthesis were stimulated by EGF, PDGF, aFGF and bFGF, but remained unaffected by TGF-beta1. Gel-filtration chromatography revealed that these effects of cytokines on HA synthesis were predominantly confined to the production of high molecular mass (>106 kDa) species. Co-exposure of cells to both cytokines and Streptomyces hyaluronidase revealed that (1) the elevated migration of control fetal fibroblasts was inhibited by hyaluronidase, (2) this inhibition was partially restored by co-exposure to EGF, PDGF, aFGF and bFGF, but remained unaffected by TGF-beta1, (3) the migration of control adult fibroblasts was unaffected by hyaluronidase and partially stimulated by EGF, aFGF and bFGF (when compared to the effects of these cytokines on cells cultured in the absence of hyaluronidase) and (4) neither PDGF nor TGF-beta1 affected the migration of hyaluronidase-treated adult cells. Linear regression analysis revealed a significant correlation between cell migration and HA synthesis by both fetal and adult fibroblasts in the presence and absence of cytokines (r2=0.9277, P<0.0001), with the exception of adult fibroblasts exposed to PDGF. Taken together, these findings suggest that (1) the migration of fetal and adult fibroblasts is differentially modulated by exogenous cytokines and (2) with the possible exception of the effects of PDGF on adult fibroblasts, cytokine-induced modulation of cell migration appears to utilise both HA-dependent and HA-independent pathways.

Adult↗
PubMed2003

Urokinase potentiates PDGF-induced chemotaxis of human airway smooth muscle cells.

We investigated the chemotactic action of PDGF and urokinase on human airway smooth muscle (HASM) cells in culture. Cells were put in collagen-coated transwells with 8-micro m perforations, incubated for 4 h with test compounds, then fixed, stained, and counted as migrated nuclei by microscopy. Cells from all culture conditions showed some basal migration (migration in the absence of stimuli during the assay), but cells preincubated for 24 h in 10% FBS or 20 ng/ml PDGF showed higher basal migration than cells quiesced in 1% FBS. PDGF(BB), PDGF(AA), and PDGF(AB) were all chemotactic when added during the assay. PDGF chemotaxis was blocked by the phosphatidyl 3'-kinase inhibitor LY-294002, the MEK inhibitor U-0126, PGE(2), formoterol, pertussis toxin, and the Rho kinase inhibitor Y-27632. Urokinase alone had no stimulatory effect on migration of quiescent cells but caused a dose-dependent potentiation of chemotaxis toward PDGF. Urokinase also potentiated the elevated basal migration of cells pretreated in 10% FBS or PDGF. This potentiating effect of urokinase appears to be novel. We conclude that PDGF and similar cytokines may be important factors in airway remodeling by redistribution of smooth muscle cells during inflammation and that urokinase may be important in potentiating the response.

Becaplermin↗
PubMed2003

Effect of prolonged hyperdynamic endotoxemia on jejunal motility in fasted and enterally fed pigs.

OBJECTIVE: To determine the effects of hyperdynamic endotoxemia on the motility of the small intestine. SUMMARY BACKGROUND DATA: Motility disorders of the gastrointestinal tract are a common complication of sepsis. It has been suggested that gram-negative endotoxin plays a role in the pathogenesis of the accompanying diarrhea frequently observed. METHODS: Pigs were infused with lipopolysaccharide for a 24-hour period. During this fasting period jejunal motility was measured using ambulatory manometry. One and 4 days after cessation of endotoxin, pigs were enterally fed, and again motility was recorded. RESULTS: Hyperdynamic endotoxemia was achieved in this model. Manometric pressure recordings revealed that endotoxin infusion accelerated the migrating motor complex (MMC) migration along the jejunum. Also, a simultaneous increase in MMC cycling frequency was observed in the endotoxin-treated group. Elevated MMC migration velocity and cycling frequency were maintained the following day after endotoxin during feeding and returned to basal values 4 days after endotoxin. CONCLUSIONS: A small dose of continuously infused endotoxin significantly provokes jejunal motility disturbances that may contribute to diarrhea.

Animals↗
PubMed2004

MKP-1 expression and stabilization and cGK Ialpha prevent diabetes- associated abnormalities in VSMC migration.

Diabetes mellitus is a major risk factor in the development of atherosclerosis and cardiovascular disease conditions, involving intimal injury and enhanced vascular smooth muscle cell (VSMC) migration. We report a mechanistic basis for divergences between insulin's inhibitory effects on migration of aortic VSMC from control Wistar Kyoto (WKY) rats versus Goto-Kakizaki (GK) diabetic rats. In normal WKY VSMC, insulin increased MAPK phosphatase-1 (MKP-1) expression as well as MKP-1 phosphorylation, which stabilizes it, and inhibited PDGF-mediated MAPK phosphorylation and cell migration. In contrast, basal migration was elevated in GK diabetic VSMCs, and all of insulin's effects on MKP-1 expression and phosphorylation, MAPK phosphorylation, and PDGF-stimulated migration were markedly inhibited. The critical importance of MKP-1 in insulin inhibition of VSMC migration was evident from several observations. MKP-1 small interfering RNA inhibited MKP-1 expression and abolished insulin inhibition of PDGF-induced VSMC migration. Conversely, adenoviral expression of MKP-1 decreased MAPK phosphorylation and basal migration rate and restored insulin's ability to inhibit PDGF-directed migration in GK diabetic VSMCs. Also, the proteasomal inhibitors lactacystin and MG132 partially restored MKP-1 protein levels in GK diabetic VSMCs and inhibited their migration. Furthermore, GK diabetic aortic VSMCs had reduced cGMP-dependent protein kinase Ialpha (cGK Ialpha) levels as well as insulin-dependent, but not sodium nitroprusside-dependent, stimulation of cGMP. Adenoviral expression of cGK Ialpha enhanced MKP-1 inhibition of MAPK phosphorylation and VSMC migration. We conclude that enhanced VSMC migration in GK diabetic rats is due at least in part to a failure of insulin-stimulated cGMP/cGK Ialpha signaling, MKP-1 expression, and stabilization and thus MAPK inactivation.

Animals↗
PubMed1997

Restraint stress-induced elevation of endogenous glucocorticoid suppresses migration of granulocytes and macrophages to an inflammatory locus.

It has been reported that restraint stress gives rise to various immunosuppressive events. In the present study, we focused our interest on an early stage of the host-defense system in which granulocytes, macrophages and natural killer (NK) cells are involved. We observed that an elevation of endogenous glucocorticoid levels in mice induced by 24 h-restraint stress (acute stress) did not significantly reduce the NK activity of the spleen cells but profoundly suppressed the migration of macrophages and granulocytes into peritoneal cavities of the mice at 24 h after an intraperitoneal injection of proteose peptone. The reduced number of the migrated granulocytes and macrophages corresponded to a down-regulated gene expression of such chemotactic factors as MCP-1/JE in the peritoneal exudate cells of the stress-loaded mice. The stress-loaded mice recovered from such a suppressive state upon treatment with the glucocorticoid antagonist, RU-486, or upon adrenalectomy, suggesting that the elevated level of endogenous glucocorticoid is responsible for these suppressive effects of acute stress.

Adrenalectomy↗
PubMed2000

Elevation of plasma cortisol during the spawning migration of landlocked kokanee salmon (Oncorhynchus nerka kennerlyi).

Kokanee salmon (Oncorhynchus nerka kennerlyi ), a landlocked subspecies of sockeye salmon, exhibited hypothalamic-pituitary interrenal (HPI, adrenal homologue) axis activation and an increase in plasma cortisol concentration up to 639 +/- 55.9 ng/ml in association with upstream migration in the upper Colorado River even though they were not exposed to a change in salinity and lengthy migration. Kokanee salmon were collected at various stages of migration and concomitant sexual maturation. The pattern of cortisol elevation in kokanee is similar to that in ocean-run sockeye salmon (O. nerka nerka). The presence of plasma cortisol elevation in an upstream migrating, landlocked Pacific salmon suggests that stressors previously considered to cause the cortisol increase, such as long-distance migration and changes in salinity, may not be primary causes of the HPI axis activation.

Animals↗
PubMed2004

Polyamine synthesis inhibition attenuates vascular smooth muscle cell migration.

Vascular smooth muscle cell migration, occurring after intimal injury, is a substantial clinical problem in atherosclerosis and restenosis after stenting. Here we investigate the effects of polyamine synthesis inhibition on vascular smooth muscle cell migration after maximal and submaximal growth stimulation with PDGF-AB or FCS. Vascular smooth muscle cells were obtained from mouse aorta explants. These cells coexpressed smooth muscle alpha-actin, PDGFRalpha and PDGFRbeta as demonstrated by immunocytochemistry. Treatment with a high (100 ng/ml) concentration of PDGF-AB stimulated DNA synthesis 6-fold and markedly elevated cell migration. PDGF-AB (100 ng/ml) increased cellular spermidine concentration 2-fold, but had no effect on spermine or putrescine levels. Treatment with the polyamine synthesis inhibitors CGP48664 (1 microM) and DFMO (5 mM) prevented the PDGF-AB-induced increase in spermidine and reduced spermine concentrations, but had no effect on PDGF-AB-stimulated DNA synthesis or cell migration. Cell migration after submaximal stimulation with either PDGF-AB (8 ng/ml) or FCS (8%) was, however, inhibited by the polyamine synthesis blockers. In summary, these data show that polyamine synthesis inhibition attenuates vascular smooth muscle cell migration under submaximal growth-stimulating conditions, suggesting that polyamines participate in regulation of cell migration and that treatment with polyamine synthesis inhibitors might reduce vascular smooth muscle cell migration after intimal injury.

Actins↗
PubMed2004

Regulation of biological activity of laminin-5 by proteolytic processing of gamma2 chain.

Laminin-5 (LN5), which regulates both cell adhesion and cell migration, undergoes specific extracellular proteolytic processing at an amino-terminal region of the gamma2 chain as well as at a carboxyl-terminal region of the alpha3 chain. To clarify the biological effect of the gamma2 chain processing, we prepared a human recombinant LN5 with the 150-kDa, non-processed gamma2 chain (GAA-LN5) and natural LN5 with the 105-kDa, processed gamma2 chain (Nat-LN5). Comparison of their biological activities demonstrated that GAA-LN5 had an about five-times higher cell adhesion activity but an about two-times lower cell migration activity than Nat-LN5. This implies that the proteolytic processing of LN5 gamma2 chain converts the LN5 from the cell adhesion type to the cell migration type. It was also found that human gastric carcinoma cells expressing the LN5 with the non-processed gamma2 chain is more adherent but less migratory than the carcinoma cells expressing a mixture of LN5 forms with the processed gamma2 chain and with the unprocessed one. The functional change of LN5 by the proteolytic processing of the gamma2 chain may contribute to elevated cell migration under some pathological conditions such as wound healing and tumor invasion.

Adenocarcinoma↗
PubMed2001

Influence of cytotoxicity and compound precipitation on test results in the alkaline comet assay.

We use the comet assay as part of our genotoxicity screening battery for newly synthesized drug candidates. A dataset of more than 250 tests carried out with 75 drug candidates of various chemical classes was analyzed to elucidate the influence of cytotoxicity and compound precipitation on DNA migration in the comet assay. Using a V79 Chinese hamster cell line, 38 of the compounds were negative and 37 were positive in the comet assay. The reproducibility of test results between repeat experiments was 85%. Data on 72 tests with a negative call in which the compounds were tested up to highly cytotoxic concentrations demonstrated that cytotoxicity, as determined by Trypan blue dye exclusion and occurrence of cells with completely fragmented chromatin, did not lead to false positive test results. The majority (64.2%) of compounds with a positive call induced elevated DNA migration in the absence of excessive cytotoxicity. Compound precipitation was observed in 84 tests. In 88.1% of these cases, the test result at the precipitating concentration did not differ from that found at the highest soluble concentration. Half of the remaining 11.9% of contrary results (most of them weak effects) were not reproducible in the respective repeat experiment, indicating no or only a negligible influence of precipitation on test results. The data indicate that using V79 cells, the comet assay specifically detects genotoxic effects and is not confounded by cytotoxicity or compound precipitation under the conditions used.

Animals↗