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PubMed1980

The importance of ammonia in the metabolic effects of hydrazine.

Acute exposure to hydrazine (N2H4), Mol. Wt.: 32.05, an importance liquid rocket propellant and parent compound of useful pharmaceutical agents such as isoniazid and hydralazine and other chemical compounds, produces severe central nervous system effects, such as coma and convulsions sometimes resulting in death. Heretofore, treatment has been symptomatic, e.g. quick-acting barbiturates for convulsions. The results of this study emphasize the importance of acute ammonia intoxication as a major component of the metabolic effects of hydrazine. Further, the results support the theory of competitive inhibition of ammonia by hydrazine (3).

Ammonia↗
PubMed1996

A micro-Raman spectroscopic study of hydrazine-treated human dental calculus.

Hydrazine has been used to remove organic components and to isolate the mineral(s) from human calculus. Micro-Raman measurements were performed on the mineral phase. After the hydrazine-treatment, not only a large reduction in fluorescence but also an increase in Raman signal was observed. The treatment was essential in minimizing thermally-induced chemical changes which could otherwise occur to the original calculus mineral due to the intense laser light. The Raman spectral features of the mineral were nearly all identical among the Raman spectra obtained at many randomly-selected sites by the micro-Raman microbe with a lateral resolution of approximately 1 micron, and were consistent with those of impure hydroxyapatite containing CO3(2-) and HPO4(2-). The spectra contained typical hydroxyapatite bands including PO4(3-)bands of the v1, v2, v3 and v4 modes and one OH- stretch band. Other minor bands due to the CO3(2-) v1 and v3 modes and bands possibly due to the HPO4(2-) v1, v2 and v4 modes were observable by the technique despite the hydrazine-treatment that could in principle remove the HPO4 and CO3 ions from the mineral. In comparison with pure synthetic hydroxyapatite, the intensity of the OH- stretch band relative to that of the PO4(3-) v1 band was approximately 70% weaker, and the bandwidth of the phosphate v1 band was 200% broader, reflecting various crystal imperfections presumably present in the calculus mineral.

Adult↗
PubMed1997

Antisymmetric Amino-Wagging Band of Hydrazine up to K' = 13 Levels

A newly recorded high-resolution infrared spectrum of hydrazine has been studied in the 729-1198 cm-1 region (the nu12 antisymmetric wagging band) with a resolution of 0.002 cm-1. About 1350 transitions with K' from 7 to 13 have been newly assigned and about 2350 transitions with lower values of K' reanalyzed with the improved precision. The effective parameters have been calculated separately for each value of K' using the Hougen-Ohashi hamiltonian for hydrazine. The extended assignment completes the analysis of the nu12 band of hydrazine. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
PubMed2000

Comparison of DNA lesions produced by tumor-inhibitory 1,2-bis(sulfonyl)hydrazines and chloroethylnitrosoureas.

1,2-Bis(sulfonyl)hydrazine derivatives, designed to generate several of the electrophilic species classically believed to be responsible for the alkylating (chloroethylating) and/or carbamoylating activities of the chloroethylnitrosoureas (CNUs), were compared with respect to the cross-linking and nicking of T7 DNA to that caused by 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), and 1-(2-chloroethyl)-3-(4-trans-methylcyclohexyl)-1-nitrosourea (MeCCNU). In the case of BCNU, a large proportion of T7 DNA strand nicking was found to be due to the generation of 2-chloroethylamine, produced from the hydrolysis of 2-chloroethylisocyanate, in turn formed during the decomposition of the parental nitrosourea. 1,2-Bis(methylsulfonyl)-1-(2-chloroethyl)hydrazine (compound 1) gave a greater yield of DNA cross-links than the CNUs. Compound 1, as well as its derivatives that were incapable of generating 2-chloroethylisocyanate, did not produce detectable levels of strand nicking, indicating that N7-alkylation of guanine did not occur to a significant extent with these agents. Since compound 1 and its derivatives are believed to generate chloronium and chloroethyldiazonium ions, it would appear that these species could not be significantly involved in the N7-alkylation of guanine caused by the CNUs. The relatively low level of N7-alkylation of guanine residues and the relatively high yield of cross-links generated by some of the 1,2-bis(sulfonyl)-1-(2-chloroethyl)hydrazine derivatives implies that they are more exclusive O6-guanine chloroethylating agents than the CNUs. O6-Guanine chloroethylation is believed to be the therapeutically relevant event produced by the CNUs; therefore, compound 1 derivatives represent promising new cancer chemotherapeutic agents, since they appear to generate lower quantities of therapeutically unimportant, yet carcinogenic lesions, and more of the therapeutically relevant O6-guanine chloroethylation than the CNUs.

Antineoplastic Agents, Alkylating↗
PubMed1998

Detection of oxidative mutagenesis by isoniazid and other hydrazine derivatives in Escherichia coli WP2 tester strain IC203, deficient in OxyR: strong protective effects of rat liver S9.

Strain IC203, deficient in the OxyR function, was sensitive to both cytotoxic and mutagenic effects of isoniazid (INH) whereas its parent, WP2 uvrA/pKM101, was resistant to these effects. Four other hydrazine compounds, hydrazine hydrate (HZH), phenylhydrazine (PHZ), hydralazine (HLZ) and nialamide (NLD), were mutagenic in WP2 uvrA/pKM101. Increases in mutagenicity were observed in IC203 for HZH and PHZ but not for HLZ and NLD. Growth inhibition zones by HZH, PHZ and NLD were larger in IC203 than in WP2 uvrA/pKM101. The enhancements in the effects of INH, HZH and PHZ in IC203 with respect to its oxyR+ parent are considered to be caused by the production of reactive oxygen species. This is consistent with its inhibition in IC203 by S9 from liver of uninduced rats, probably through the action of catalase. Mutagenicities of INH, PHZ and HLZ were low in strains IC204, a derivative of WP2 uvrA carrying a deletion of the umuDC genes, and IC206, a derivative of IC204 deficient in the MutY glycosylase. In these strains, HZH and NLD induced a high level of revertants which carry suppressor mutations resulting exclusively from G:C-A:T transitions, thus suggesting a direct reaction of the two hydrazines with cytosine.

Animals↗
PubMed1997

Aryldiazene, Aryldiazenido, and Hydrazine Complexes of Manganese. Preparation, Characterization, and X-ray Crystal Structures of [Mn(CO)(3)(4-CH(3)C(6)H(4)N=NH){PPh(OEt)(2)}(2)]BF(4) and [Mn(CO)(3)(NH(2)NH(2)){PPh(OEt)(2)}(2)]BPh(4) Derivatives.

Aryldiazene complexes [Mn(CO)(3)(ArN=NH)P(2)]BF(4) (1, 2) and [{Mn(CO)(3)P(2)}(2)(&mgr;-HN=NArArN=NH)](BF(4))(2) (3, 4) [P = PPh(OEt)(2), PPh(2)OEt; Ar = C(6)H(5), 2-CH(3)C(6)H(4), 4-CH(3)C(6)H(4), 4-CH(3)OC(6)H(4); ArAr = 4,4'-C(6)H(4)C(6)H(4), 4,4'-(2-CH(3))C(6)H(3)C(6)H(3)(2-CH(3)), 4,4'-C(6)H(4)CH(2)C(6)H(4)] were prepared by reacting hydride species MnH(CO)(3)P(2) with the appropriate aryldiazonium cations in CH(2)Cl(2) or acetone solutions at -80 degrees C. The compounds were characterized by IR, (1)H and (31)P NMR spectra (with (15)N isotopic substitution), and a single-crystal X-ray structure determination. The complex [Mn(CO)(3)(4-CH(3)C(6)H(4)N=NH){PPh(OEt)(2)}(2)]BF(4) (1c) crystallizes in the space group C2/c with a = 31.857(5) Å, b = 11.119(2) Å, c = 22.414(3) Å, beta = 97.82(1) degrees, and Z = 8. Treatment of aryldiazene compounds 1-4 with NEt(3) gave the pentacoordinate aryldiazenido [Mn(CO)(2)(ArN(2))P(2)] (5, 6) and [{Mn(CO)(2)P(2)}(2)(&mgr;-N(2)ArArN(2))] (7, 8) [P = PPh(OEt)(2), PPh(2)OEt; Ar = C(6)H(5), 4-CH(3)C(6)H(4); ArAr = 4,4'-C(6)H(4)C(6)H(4), 4,4'-(2-CH(3))C(6)H(3)C(6)H(3)(2-CH(3))] derivatives. Protonation reactions of these aryldiazenido complexes 5-8 with HCl afforded the aryldiazene [MnCl(CO)(2)(ArN=NH)P(2)] (9) and [{MnCl(CO)(2)P(2)}(2)(&mgr;-HN=NArArN=NH)] (10) derivatives. Hydrazine complexes [Mn(CO)(3)(RNHNH(2))P(2)]BPh(4) (11, 12) [P = PPh(OEt)(2), PPh(2)OEt; R = H, CH(3), C(6)H(5), 4-NO(2)C(6)H(4)] were prepared by allowing hydride species MnH(CO)(3)P(2) to react first with triflic acid and then with the appropriate hydrazine. Their characterization by IR, (1)H and (31)P NMR spectra, and an X-ray crystal structure determination is reported. The compound [Mn(CO)(3)(NH(2)NH(2)){PPh(OEt)(2)}(2)]BPh(4) (11a) crystallizes in the space group P&onemacr; with a = 13.772(3) Å, b = 14.951(4) Å, c = 13.319(3) Å, alpha = 104.47(1) degrees, beta = 100.32(1) degrees, gamma = 111.08(1) degrees, and Z = 2. Oxidation reactions of hydrazine compounds 11 and 12 with Pb(OAc)(4) at -40 degrees C gave stable aryldiazene [Mn(CO)(3)(RN=NH)P(2)]BPh(4) and thermally unstable (upon reaching -40 degrees C) diazene [Mn(CO)(3)(HN=NH)P(2)]BPh(4) derivatives.

Journal Article↗
PubMed2005

Fluorinated heterocyclic compounds. An effective strategy for the synthesis of fluorinated Z-oximes of 3-perfluoroalkyl-6-phenyl-2h-1,2,4-triazin-5-ones via a ring-enlargement reaction of 3-benzoyl-5-perfluoroalkyl-1,2,4-oxadiazoles and hydrazine.

The reaction of 3-benzoyl-5-perfluoroalkyl-1,2,4-oxadiazoles with hydrazine has been investigated, evidencing the possibility of competitive reaction paths. Nucleophilic addition of the hydrazine to the electrophilic C(5) of the 1,2,4-oxadiazole ring, followed by ring opening and ring closure with enlargement, leads with high yield and in very mild experimental conditions to the formation of Z-oximes of 3-perfluoroalkyl-6-phenyl-2H-1,2,4-triazin-5-ones (11a-c) as major products of the reaction. In turn, the hydrazine can attack the electrophilic carbonyl carbon giving 4-perfluoroacylamino-5-phenyl-2H-1,2,3-triazoles (13a-c) through the well-known Boulton-Katritzky rearrangement of the intermediate hydrazones.

Journal Article↗
PubMed2004

Reaction of bis(2,4-dinitrophenyl) phosphate with hydrazine and hydrogen peroxide. Comparison of O- and N- phosphorylation.

Nonionic hydrazine reacts with anionic bis(2,4-dinitrophenyl) phosphate (BDNPP), giving 2,4-dinitrophenyl hydrazine and dianionic 2,4-dinitrophenyl phosphate by an S(N)2(Ar) reaction, and at the phosphoryl center, giving 2,4-dinitrophenoxide ion and a transient phosphorylated hydrazine that rearranges intramolecularly to N-(2,4-dinitrophenyl)-N-phosphonohydrazine. Approximately 58% of the reaction at pD = 10 occurs by N-phosphorylation, as shown by (31)P NMR spectroscopy. Reaction of HO(2)(-) is wholly at phosphorus, and the intermediate peroxophosphate reacts intramolecularly, displacing a second 2,4-dinitrophenoxide ion, or with H(2)O(2), giving 2,4-dinitrophenyl phosphate and O(2). Rate constants of O- and N-phosphorylation in reactions at phosphorus of NH(2)NH(2), HO(2)(-), and NH(2)OH and its methyl derivatives follow Bronsted relationships with similar slopes, but plots differ for oxygen and nitrogen nucleophiles. The reaction with NH(2)NH(2) has been probed by using both NMR spectroscopy and electrospray ionization mass and tandem mass spectrometry, with the novel interception of key reaction intermediates in the course of reaction.

Journal Article↗
PubMed2000

Nucleophilic addition of hydroxylamine, methoxylamine, and hydrazine to malononitrileoxime

The chemistry of malononitrileoxime, HONC(CN)(2), with respect to nucleophilic addition to ammonia, methylamine, hydroxylamine, methoxylamine, and hydrazine is reported. Whereas the poorly nucleophilic ammonia and methylamine do not react, hydroxylamine, methoxylamine, and hydrazine add to the nitrile groups of the oxime, yielding the corresponding amidoximes and amidrazones. Depending on the stoichiometry of the reactions, hydroxylamine and hydrazine add to one or both of the nitrile groups; methoxylamine adds to only one of the nitrile groups. Three of the products, namely, cyanoacetamidoxime (1), 3-amino-2,3-hydroxyiminopropionitrile monohydrate (2.H(2)O), and 3,5-diaminopyrazolone-4-oxime monohydrochloride monohydrate (6.HCl.H(2)O), are characterized by single-crystal X-ray diffraction data. All of the products exhibit exothermic decomposition properties with heats of decomposition in the range of 500-1500 kJ mol(-)(1).

Journal Article↗
PubMed2006

Threshold-photoelectron spectroscopic study of methyl-substituted hydrazine compounds.

The valence shell electronic structures of methylhydrazine (CH(3)NHNH(2)), 1,1-dimethylhydrazine ((CH(3))(2)NNH(2)) and tetramethylhydrazine ((CH(3))(4)N(2)) have been studied by recording threshold and conventional (kinetic energy resolved) photoelectron spectra. Ab initio calculations have been performed on ammonia and the three methyl substituted hydrazines, with the structures being optimized at the B3-LYP/6-31+G(d) level of theory. The ionization energies of the valence molecular orbitals were calculated using the Green's function method, allowing the photoelectron bands to be assigned to specific molecular orbitals. The ground-state adiabatic and vertical ionization energies, as determined from the threshold photoelectron spectra, were IE(a) = 8.02 +/- 0.16 eV and IE(v) = 9.36 +/- 0.02 eV for methylhydrazine, IE(a) = 7.78 +/- 0.16 eV and IE(v) = 8.86 +/- 0.01 eV for 1,1-dimethylhydrazine and IE(a) = 7.26 +/- 0.16 eV and IE(v) = 8.38 +/- 0.01 eV for tetramethylhydrazine. Due to the large geometry change that occurs upon ionization, these IE(a) values are all higher than the true thresholds. New features have been observed in the inner valence region and these have been compared with similar structure in the spectrum of hydrazine. The effect of resonant autoionization on the threshold photoelectron yield is discussed. New heats of formation (Delta(f)H) are proposed for the three hydrazines on the basis of G3 calculations: 107, 94, and 95 kJ/mol for methylhydrazine, 1,1-dimethyhydrazine and tetramethylhydrazine, respectively. The previously reported Delta(f)H for tetramethylhydrazine is shown to be erroneous.

Journal Article↗
PubMed1998

The hydrazine derivative aminoguanidine inhibits the reaction of tetrahydrofolic acid with hydroxymethylarginine biomolecule.

UNLABELLED: Aminoguanidine (AG), a hydrazine derivative is known to inhibit the formation of Advanced Glycosylation Endproducts (AGE) and AG has been proposed as an agent in prophylaxis of diabetic complications. However, treatment with hydrazine produced liver and lung tumors by formation of N7- and O6-methylguanine in the DNA of rodents. The hydrazine derivative, isonicotinic acid hydrazide induced pulmonary tumors in mice. N(G)-hydroxymethyl-arginine (HMA) was synthesized by our research group and it showed anticancer effect against experimental tumors. HMA was found earlier in human blood and urine, and recently in many plants (in fruits and vegetables). We could demonstrate a reaction (pH = 7.5, 37 degrees C, 1h) between HMA and tetrahydrofolate (THF) producing N5,N10-methylene-tetrahydrofolate (CH2-THF), the coenzyme of thymidylate synthase (TS). In model experiments AG proved to react with formaldehyde (HCHO) and to eliminate the C1-fragment of HMA, but not that of CH2-THF. In the presence of AG burst chemiluminescence and a higher speed of the formylation and methylation reactions were found in the AG, HCHO, hydrogen peroxide (H2O2) and L-lysine system than without AG. CONCLUSIONS: HMA as a biomolecule is one of the compounds which are responsible for the endogenous HCHO level. The biochemical function of HMA may be the direct supply of C1-fragment for the folate cycle. AG can disturb the above function of HMA. The reaction between AG and HCHO seems to be dangerous for biological systems because of the possible presence of L-lysine and H2O2. The burst chemiluminescence indicates excited molecules with extreme high energy producing uncontrolled formylation and methylation reactions. Considering the results of the experiments with AG its use as a medicament seems to be questionable.

Animals↗
PubMed1997

[Importance of toxicological studies in animals for elaboration of pathogenetic therapy of hydrazine intoxication].

Pathogenesis of poisoning with hydrazine seems complicated. Hydrazines inhibit pyridoxal-dependent enzymes, interfere with carbohydrates transformation and lipid metabolism, alter the processes of energy metabolism. Treatment of poisoning with hydrazine is effective only when containing drug combinations. Based experimentally, recommendations on the combination (phenazepam, be methyl, piracetam, ionol) were supported by chemical testing of the drugs.

Adjuvants, Immunologic↗
PubMed1985

Novel bis(5-arylamino-2-oxo-4-thiazolidinylidene)hydrazine derivatives as potential antineoplastic agents.

A new series of N,N'-bis(5-arylamino-3-benzyl-2-oxo-4-thiazolidinylidene)hydrazine s has been prepared for potential anticancer activity. The synthesis was achieved by reacting 3-benzylthiazolidin-2-one-4-thione with its 4-hydrazone derivative to give N,N'-bis(3-benzyl-2-oxo-4-thiazolidinylidene)hydrazine, which was subjected to dibromination followed by reaction with various primary aromatic amines. Some compounds were evaluated against leukemia P 388 in the mouse. No significant antitumor activity was observed.

Animals↗
PubMed1994

Further studies on physicochemical properties of mitochondrial membranes during the formation process of megamitochondria in the rat liver by hydrazine.

Physicochemical properties of lipids extracted from hepatic mitochondria of rats fed with 1% hydrazine diet for 3 days (3H-mitochondria) and 7 days (7H-mitochondria) were studied using differential scanning calorimetry and the fluorescence polarization measurements. Results obtained from lipids extracted from 3H-mitochondria were as follows: (1) Thermotropic phase transition temperatures (Tm) were elevated with a distinct increase in transition enthalpy (delta H) compared to those of the control due to increases in relative amounts of phosphatidylethanolamine (PE) and phosphatidylserine (PS) in phospholipid species. (2) Tm in lipids and phospholipids extracted from 3H-mitochondria was elevated with decreases in delta H after the addition of Ca2+, whereas delta H of the control was increased after the addition of Ca2+. (3) Phosphatidylcholine (PC) liposomes containing PE or PS at concentrations corresponding to PE/PC or PS/PC ratio in 3H-mitochondria showed elevations of transition temperatures with decreases in delta H values after the addition of Ca2+, whereas those containing PE or PS ratio at concentrations corresponding to PE/PC or PS/PC in the control mitochondria showed increases in delta H values after the addition of Ca2+. (4) There were essentially no changes in membrane fluidity between lipids extracted from 3H-mitochondria and those extracted from the control mitochondria. Addition of Ca2+ to lipids extracted from 3H-mitochondria, however, caused elevation of membrane fluidity while those extracted from the control mitochondria showed no changes in membrane fluidity after the addition of Ca2+. (5) Increases in the ratio of unsaturated fatty acids to saturated fatty acids (U/S ratio) in phospholipids extracted from 3H-mitochondria were found to be mainly due to those in PS. These data may suggest that hydrazine modifies the membrane of mitochondria favorable for the membrane fusion via enhanced acidic phospholipid-Ca2+ interactions.

Animals↗
PubMed1995

Oncogenic potential of inhaled hydrazine in the nose of rats and hamsters after 1 or 10 1-hr exposures.

Hydrazine (N2H4) is used as a fuel for missiles and standby power systems of operational military aircraft. Maintenance of missiles and aircraft may result in accidental human exposure to high concentrations for brief periods of time. The purposes of this study were to assess the oncogenic potential of N2H4 in rats and male hamsters exposed to a high concentration of N2H4 for repeated short exposures and to investigate the relationships of acute and subchronic effects of N2H4 to nasal tumorigenesis. In phase 1 (acute and subchronic) and Phase 2 (lifetime experiments, groups of male and female Fischer 344 rats and male Syrian golden hamsters were exposed by inhalation to 0, 75 (Phase 2 only), or 750 ppm N2H4 for 1 (acute) or 10 (subchronic) 1-hr weekly exposures. Rodents were euthanized 24 hr after exposures 1 and 10 and 24 to 30 months poststudy initiation. Significant reductions in body weight were observed in N2H4-treated rodents compared to controls during the exposure interval. No hydrazine-induced mortality was detected. Histopathologic examination after the acute and subchronic exposures revealed degeneration and necrosis of transitional, respiratory, and olfactory epithelia in the anterior nose and, in rats exposed subchronically, squamous metaplasia of the transitional epithelium. Minimal to mild rhinitis resulted from N2H4 exposures. Apoptosis was observed in olfactory and squamous metaplastic transitional epithelium. Lesions occurred at sites reportedly having high air-flow and generally appeared to be more severe in the anterior portion of the nose. By 24 months, the squamous metaplastic transitional epithelium reverted back to normal-appearing transitional epithelium. By 24+ months, low incidences (sexes combined) of hyperplasia (5/194, 2.6%) and neoplasia (11/194, 5.7%) were detected, principally in the transitional epithelium of the 750 ppm N2H4-treated rats. A similar incidence of hyperplasia (2/94, 2%) and neoplasia (5/94, 5.3%) was detected in the high-exposure group of hamsters. The location and type of N2H4-induced proliferative lesions were similar to those reported in a chronic N2H4-exposure study (5.0 ppm x 6 hr/day x 5 days/week for 1 year) conducted in our laboratory, but the chronic study had much higher incidences (rats, sexes combined: hyperplasia 15.5% vs 2.6% and polypoid adenoma 44.6% vs 5.2%). The product (CD) of concentration + time was the same (750 ppm hours) for the high-dose groups for both studies, but the duration of exposure was 150 x longer and the concentration was 150 x lower in the chronic study.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenomatous Polyps↗
PubMed1979

Clinical study of hydrazine sulfate in advanced cancer patients.

Twenty-five patients with a variety of solid tumors were treated with hydrazine sulfate. Hydrazine was given orally in the form of 60 mg capsules from one to four times daily. No patient had a 50% reduction of tumor size. Subjective benefit was seen in three patients but it was of brief duration.

Adolescent↗
PubMed1980

Induction of sister chromatid exchanges by hydroxylamine, hydrazine and isoniazid and their inhibition by cysteine.

Experiments were performed in order to gain information about the primary process leading to the production of sister chromatid exchanges (SCEs). Radical-forming substances (hydroxylamine, hydrazine and the antituberculous drug isoniazid) were examined for their effectiveness in inducing SCEs. All three substances proved successful in the induction of SCEs in the V-79 cell line of the Chinese hamster. By simultaneous application of a sulfhydryl compound (cysteine), a reduction of the hydrazine- and isoniazid-induced SCEs was achieved. Isoniazid was additionally examined in the in vivo SCE-test. At concentrations of 2-100 mg/kg body weight, it does not increase the rate of SCEs in the bone marrow of the Chinese hamster.

Animals↗
PubMed1984

Induction of endoreduplication by hydrazine in Chinese hamster V 79 cells and reduced incidence of sister chromatid exchanges in endoreduplicated mitoses.

Hydrazine in high concentrations very effectively induces endoreduplication in Chinese hamster V79 cells. The addition of 5-bromodeoxyuridine (BrdU) for the duration of one cell cycle prior to the induction of endoreduplication produces diplochromosomes with sister chromatid differentiation (SCD) after differential chromatid staining. The fact that diplochromosomes with complete SCD are obtained shows that endoreduplication was induced in cells that were in G2-phase. The analysis of sister chromatid exchanges (SCEs) showed that hydrazine treatment rarely led to increased SCE frequencies in mitoses after endoreduplication, but that it caused a strong SCE induction in diploid second division metaphases in the same culture. Neither catalase nor cysteine had an effect on the induction of endoreduplication or the incidence of SCEs. Treatment of the cells with mitomycin C prior to addition of BrdU led to increased SCE frequencies. Compared with the normal mitoses from the same preparation, the mitoses after endoreduplication showed a significantly reduced induction of SCEs. In contrast to these findings, SCE induction was not reduced in the common tetraploid V 79 cells after colcemid-induced polyploidization.

Animals↗