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PubMed1990

Structure-activity studies on organoselenium alkylating agents.

A variety of organoselenium alkylating agents were synthesized, using 2-hydroxyethyl and 3-hydroxypropyl selenocyanate intermediates, and studied to determine their chemical reactivities with 4-(4-nitrobenzyl)pyridine (NBP) and cytotoxicities against CCRF-CEM, L1210/0, and L1210/L-PAM cells. The comparison between the 2-chloroethyl sulfides and selenides 1-4 revealed the markedly enhanced nucleophilicity of selenium (Se) over sulfur (S) by two or more orders of magnitude. This finding indicates that a major consideration in the design of antitumor alkylating organoselenides is the reactivity of selenium. A Taft plot of the experimental first-order rate constant, knbp, and sigma* in a series of 2-chloroethylseleno compounds gave a slope of -1.73 (rho*), with the exception of 2-chloroethyl 2-nitrophenyl selenide (10). The anomalous behavior of 10 is explained in terms of the ortho-nitro stabilization effect directly interacting with the selenium atom of ethyleneselenonium ion to form a 5-membered cyclic intermediate. In the same series, a 5000-fold difference in alkylating reactivity offered only a sixfold variation in cytotoxicity against CCRF-CEM cells. Increasing the alkylating chain length from ethlene to propylene units markedly reduced alkylating reactivities. In the CH3Se(CH2)n Cl series, 16 (n = 3) was 1.5 X 10(5) times slower than 2 (n = 2) in NBP alkylation, revealing that 3-chloro-n-propyl selenides are not chemically reactive enough to be biological alkylating agents despite the presence of the highly nucleophilic selenium atom. Replacement of chloride with mesylate in 3-substituted propyl selenides, such as 17 and 20, restored desirable reactivities and cytotoxicities.

Alkylating Agents↗
PubMed2002

Successful treatment of serpiginous choroiditis with alkylating agents.

OBJECTIVE: To describe the management and long-term outcomes of patients with serpiginous choroiditis treated with alkylating agents. DESIGN: Retrospective, noncomparative case series. PARTICIPANTS: Nine patients with active, vision-threatening serpiginous choroiditis who had progressive inflammation while on steroids and/or immunosuppressive agents other than alkylating agents treated at three tertiary care uveitis referral centers. METHODS: Patients received systemic immunosuppression with an alkylating agent, either chlorambucil or cyclophosphamide. Prednisone also was given initially and was tapered and discontinued. MAIN OUTCOME MEASURES: Visual acuity, clinical disease activity, duration of treatment, duration of drug-free disease remission, and side effects of alkylating agent therapy. RESULTS: No patients had recurrences while on therapy. No further visual loss was encountered after starting the therapy. Six of the patients regained vision. All but two patients achieved prolonged drug-free remissions, ranging in duration between 15 and 96 months (median, 78 months). Side effects included transient bone marrow suppression, nausea, and fatigue. Secondary malignancy was encountered in one patient, whose carcinoma of the urinary bladder was treated successfully. CONCLUSIONS: Adequate immunosuppression with alkylating agents may favorably alter the long-term prognosis of patients with serpiginous choroiditis.

Adult↗
PubMed1979

Enhancement of the nuclear reactivity of alkylating agents by prednisolone.

We have compared the nuclear reactions of the alkylating agents chlorambucil, melphalan, and cyclophosphamide used alone, with those produced when the same drugs were used in combination with the corticosteroid prednisolone. Studies were performed in vivo in Wistar rats bearing ascites forms of either the Yoshida sarcoma or the Walker carcinosarcoma. Strains of both tumor lines, which were sensitive to alkylating agents, showed loss of condensed chromatin, increased phosphorylation of nuclear proteins, and increased DNA cross-linking after exposure to the alkylating agents alone; these changes were generally enhanced in the presence of prednisolone. When paired tumor lines which exhibited acquired resistance to alkylating agents were studied, no nuclear changes were detected when individual alkylating agents were given alone. However, in combination with prednisolone, each of the three alkylating agents produced loss of condensed chromatin, increased nuclear protein phosphorylation, and DNA cross-linking. These chromatin changes were associated with tumor cell death and may determine drug sensitivity in the tumors studied.

Alkylating Agents↗
PubMedDate not supplied

Potential carcinogenic and mutagenic industrial chemicals. I. Alkylating agents.

A variety of alkylating agents, acylating agents, peroxides, halogenated derivatives, and nitrogen derivatives have been reviewed, principally in terms of their synthesis, areas of utility, stability, distribution, reactivity, levels of exposure, population at risk, metabolism, carcinogenicity, and mutagenicity.

Aldehydes↗
PubMed1993

Kinetic studies of 2-(2'-Haloethyl) and 2-ethenyl substituted quinazolinone alkylating agents. Acid-catalyzed dehydrohalogenation and alkylation involving a quinazolinone prototropic tautomer.

The mechanism of halide elimination from 2-haloethyl-5,8-dihydroxyquinazolin-4(3H)-ones was studied in aqueous buffer by means of a pH-rate profile, buffer dilution studies, isotopic labeling, and kinetic isotope effects. From the results of these studies, it is apparent that a quinazolinone tautomer, arising from a prototropic shift of the C(l') proton to the N(1) position, is formed in the rate determining step of elimination. Monobasic phosphate acts as a bifunctional catalyst for the tautomerism. The halide then eliminates from the tautomer to afford the alkene derivative. Conversely, hydroxyethyl mercaptide adds to the alkene to afford the tautomer. The significance of these studies lies in the discovery of a prototropic tautomer of quinazolinone, which is reversibly formed in aqueous buffer under mild conditions, and in the discovery of alkylation chemistry useful in the design of quinazolinone-based enzyme inhibitors.

Alkylating Agents↗
PubMed2001

Induction of the SAPK activator MIG-6 by the alkylating agent methyl methanesulfonate.

The alkylating agent methylmethanesulfonate (MMS) activates the c-jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK) and the p38 mitogen-activated protein kinase (p38MAPK) pathways via different mechanisms of action. Activation of p38MAPK by MMS involves the pp125 focal adhesion kinase-related tyrosine kinase RAFTK and the MAPK kinase 3. The way in which MMS can activate JNK/SAPK has not been elucidated. Here we describe the identification by differential display of human mitogen-activated gene-6 (MIG-6) as a novel MMS-inducible gene. Induction of MIG-6 by MMS was found in human diploid skin fibroblasts and in simian virus 40-transformed skin fibroblasts, indicating that the enhanced expression of MIG-6 after MMS-treatment did not require p53. The signal leading to activation of MIG-6 appeared to be independent of DNA damage. High MIG-6 expression was found in the liver, lung, and placenta. MIG-6 is an adapter protein that binds to the activated form of cdc42Hs and to 14-3-3 proteins, thereby activating JNK/SAPKs. Our results suggest that activation of JNK/SAPKs by MMS may involve the induction of MIG-6.

Adaptor Proteins, Signal Transducing↗
PubMed2000

The clinical pharmacology of alkylating agents in high-dose chemotherapy.

Alkylating agents are widely used in high-dose chemotherapy regimens in combination with hematological support. Knowledge about the pharmacokinetics and pharmacodynamics of these agents administered in high doses is critical for the safe and efficient use of these regimens. The aim of this review is to summarize the clinical pharmacology of the alkylating agents (including the platinum compounds) in high-dose chemotherapy. Differences between conventional and high doses will be discussed.

Alkanesulfonates↗
PubMed1980

Sister-chromatid exchanges and cytotoxicity in cultured Indian muntjac cells treated with alkylating agents.

6 monofunctional alkylating mutagens/carcinogens -- 4 N-nitroso and 2 methanesulfonate compounds -- differed in their efficiency for inducing sister-chromatid exchanges (SCEs) when normalized on cytotoxicity. SCE induction occurred only at highly cytotoxic doses. Ethylating agents were, on a molar basis, generally less potent inducers of SCEs, and they were also less cytotoxic than the corresponding methylating agents. The observed differential action spectrum of the 6 alkylating agents is discussed in the light of recent ideas on the interaction between alkylating mutagens with DNA and the role of specific DNA lesions in the formation of SCEs.

Alkylating Agents↗
PubMed1991

Modulation of alkylating agents by etanidazole and Fluosol-DA/carbogen in the FSaIIC fibrosarcoma and EMT6 mammary carcinoma.

Tumor cell survival assay in the FSaIIC murine fibrosarcoma demonstrated that when the modulator Fluosol-DA (0.3 ml; 12 ml/kg i.v.) was administered just prior to an alkylating agent plus carbogen breathing for 6 h or the modulator etanidazole (1 g/kg i.p.) was administered just prior to an alkylating agent, the combination treatment produced significantly more tumor cell killing across the dosage range of each alkylating agent tested compared with the alkylating agent alone. Each alkylating agent produced a dose-dependent log-linear tumor cell survival curve. There was an increase in tumor cell killing of 5-10-fold when either Fluosol-DA/carbogen or etanidazole was added to treatment with the alkylating agent. For cis-diamminedichloroplatinum(II) (CDDP) and N,N',N''-triethylenethiophosphoramide, the modulators used in combination increased tumor cell killing by only 2-3-fold over that obtained with a single modulator, but for the other alkylating agents, tumor cell killing was increased by 10-50-fold when the combination of modulators was used. Bone marrow granulocyte-macrophage colony-forming unit survival assays showed that the combination of modulators with the alkylating agents resulted in only small increases in bone marrow toxicity of the alkylating agents except for N,N',N''-triethylenethiophosphoramide and L-phenylalanine mustard (L-PAM), for which the toxicity to the bone marrow granulocyte-macrophage colony-forming unit was increased by 5-10-fold compared with the alkylating agents alone. The Hoechst 33342 dye diffusion defined tumor cell subpopulation assay, also in the FSaIIC tumor, demonstrated that the combination of modulators increased the toxicity of CDDP, cyclophosphamide, L-PAM, and 1,3-bis(2-chloroethyl)-1-nitrosourea by 9-55-fold compared with the alkylating agent alone in both the bright (euxoic-enriched) and dim (hypoxic-enriched) cells. For each alkylating agent except 1,3-bis(2-chloroethyl)-1-nitrosourea, the increase in tumor cell killing was greater in the dim cells than in the bright cells. Finally, tumor growth delay studies in both the FSaIIC tumor and the EMT-6 murine mammary adenocarcinoma confirmed that the combination of modulators significantly increased the tumor growth delay caused by CDDP, carboplatin, cyclophosphamide, N,N'N"-triethylenethiophosphoramide, L-PAM, and 1,3-bis(2-chloroethyl)-1-nitrosourea. The greatest increases (4-5-fold) were observed for carboplatin and L-PAM in the FSaIIC tumor and CDDP and cyclophosphamide in the EMT-6 tumor. These results suggest that Fluosol-DA/carbogen together with etanidazole may be an effective modulator combination of alkylating agents in the clinic.

Alkylating Agents↗
PubMed2005

Do dose response thresholds exist for genotoxic alkylating agents?

The demonstration and acceptance of dose response thresholds for genotoxins may have substantial implications for the setting of safe exposure levels. Here we test the hypothesis that direct-acting DNA reactive agents may exhibit thresholded dose responses. We examine the potential mechanisms involved in such thresholded responses, particularly in relation to those of alkylating agents. As alkylating agents are representative model DNA reactive compounds with well characterized activities and DNA targets, they could help shed light on the general mechanisms involved in thresholded dose responses for genotoxins. Presently, thresholds have mainly been described for agents with non-DNA targets. We pay particular attention here to the contribution of DNA repair to genotoxic thresholds. A review of the literature shows that limited threshold data for alkylating agents are currently available, but the contribution of DNA repair in thresholded dose responses is suggested by several studies. The existence of genotoxic thresholds for alkylating agents methylmethanesulfonate is also supported here by data from our laboratory. Overall, it is clear that different endpoints induced by the same alkylator, can possess different dose response characteristics. This may have an impact on the setting of safe exposure levels for such agents. The limited information available concerning the dose response relationships of alkylators can nevertheless lead to the design of experiments to investigate the mechanisms that may be involved in threshold responses. Through using paired alkylators inducing different lesions, repaired by different pathways, insights into the processes involved in genotoxic thresholds may be elucidated. Furthermore, as alkyl-guanine-DNA transferase, base excision repair and mismatch repair appear to contribute to genotoxic thresholds for alkylators, cells deficient in these repair processes may possess altered dose responses compared with wild-type cells and this approach may help understand the contribution of these repair pathways to the production of thresholds for genotoxic effects in general. Finally, genotoxic thresholds are currently being described for acute exposures to single agents in vitro, however, dose response data for chronic exposures to complex mixtures are, as yet, a long way off.

Alkylating Agents↗
PubMed1996

Postlabeling detection of DNA adducts of antitumor alkylating agents.

The sensitivity for DNA adduct formation by antitumor alkylating agents (mechlorethamine, cisplatin and adozelesin) of the postlabeling technique and thin-layer chromatography was studied. Three DNAs were used: a double-stranded 20-bp oligonucleotide of defined sequence, calf thymus DNA and murine leukemia L1210 cellular DNA. With high concentrations of mechlorethamine, there was a marked decrease in normal dGp, a lesser decrease in dAp and dCp and no change in dTp. Using 2D mapping PEI-cellulose thin-layer chromatography analyses, it was found that six mechlorethamine: DNA adducts were produced after a short exposure to mechlorethamine. After an extended time at relatively high drug concentrations there was an alteration in the mechlorethamine: DNA adduct pattern that may reflect the conversion of monoadducts to crosslinked adducts. Similar observations were made with cisplatin and adozelesin. When murine leukemia L1210 cells were treated with 50 microM mechlorethamine or 50 microM cisplatin for 1 h, six or more mechlorethamine: DNA adducts and five cisplatin: DNA adducts were detected. After allowing 6 h. for repair of potentially lethal damage, several adducts were no longer detectable and others appeared with diminished intensity. Nuclease P(1) dephosphorylates normal nucleotides at relatively low enzyme concentrations with variation depending upon the nucleotide. In general, considerably lower concentrations of nuclease P1 were required to dephosphorylate the normal nucleotides than to dephosphorylate the antitumor alkylating agent: nucleotide adducts, thus allowing increased sensitivity of the postlabeling assay. The sensitivity of detection of antitumor alkylating agent: DNA adducts in DNA from treated L1210 cells approached one adduct per 10(7)-10(8) nucleotides. These results suggest that the postlabeling technique may be sufficiently sensitive and specific for the study of the clinically effective levels of antitumor alkylating agents.

Animals↗
PubMed2002

The apurinic/apyrimidinic endonuclease activity of Ape1/Ref-1 contributes to human glioma cell resistance to alkylating agents and is elevated by oxidative stress.

Alkylating agents are standard components of adjuvant chemotherapy for gliomas. We provide evidence here that Ape1/Ref-1, the major mammalian apurinic/apyrimidinic endonuclease (Ap endo), contributes to alkylating agent resistance in human glioma cells by incising DNA at abasic sites. We show that antisense oligonucleotides directed against Ape1/Ref-1 in SNB19, a human glioma cell line lacking O(6)-methylguanine-DNA-methyltransferase, mediate both reduction in Ape1/Ref-1 protein and Ap endo activity and concurrent reduction in resistance to methyl methanesulfonate and the clinical alkylators temozolomide and 1,3-(2-chloroethyl)-1-nitrosourea. An accompanying increase in the level of abasic sites indicates that the DNA repair activity of Ape1/Ref-1 contributes to resistance. Conversely, we also show that exposure of SNB19 cells to HOCl, a generator of reactive oxygen species (ROS), results in elevated Ape1/Ref-1 protein and Ap endo activity, enhanced alkylator resistance, and reduced levels of abasic sites. Given current evidence that heightened oxidative stress prevails within brain tumors, the finding that ROS increase resistance to clinical alkylators in glioma cells may have significance for the response of gliomas to alkylating agent-based chemotherapy. Our results may also be relevant to the design of therapeutic regimens using concurrent ionizing radiation (a generator of ROS) and alkylating agent-based chemotherapy.

Antineoplastic Agents, Alkylating↗
PubMed1989

The search for the molecular lesions responsible for the induction of chromosomal damage by alkylating agents.

Many studies associated specific DNA alkylation products with specific biological effects of alkylating agents. Studies dealing with the identification of DNA lesions that are responsible for chromosomal damage are reviewed in this paper. Although early evidence suggested that alkylation of high nucleophilicity centers such as N-7 of guanine was associated with genetic effects of alkylating agents, recent studies shifted the attention to the alkylation of oxygen atoms. The results of studies based on the use of cells with different capacities to repair O6-alkylguanine (O6-AlkGua) indicate a key role for this alkylation product in the induction of sister chromatid exchanges, chromosomal aberrations and micronuclei. Our own results on the influence of exogenous thymidine on the frequency of micronuclei induced by methylating and ethylating agents further suggest that mispairing of O6-AlkGua with thymine may be involved. Molecular dosimetry studies did not reveal any correlation between individual DNA alkylation products and the induction of chromosomal damage, indicating that multiple lesions are probably involved.

Alkylating Agents↗
PubMed1968

Cytotoxicity of alkylating agents towards sensitive and resistant strains of Escherichia coli in relation to extent and mode of alkylation of cellular macromolecules and repair of alkylation lesions in deoxyribonucleic acids.

1. A quantitative study was made of the relationship between survival of colony-forming ability in Escherichia coli strains B/r and B(s-1) and the extents of alkylation of cellular DNA, RNA and protein after treatment with mono- or di-functional sulphur mustards, methyl methanesulphonate or iodoacetamide. 2. The mustards and methyl methanesulphonate react with nucleic acids in the cells, in the same way as found previously from chemical studies in vitro, and with proteins. Iodoacetamide reacts only with protein, principally with the thiol groups of cysteine residues. 3. The extents of alkylation of cellular constituents required to prevent cell division vary widely according to the strain of bacteria and the nature of the alkylating agent. 4. The extents of alkylation of the sensitive and resistant strains at a given dose of alkylating agent do not differ significantly. 5. Removal of alkyl groups from DNA of cells of the resistant strains B/r and 15T(-) after alkylation with difunctional sulphur mustard was demonstrated; the product di(guanin-7-ylethyl) sulphide, characteristic of di- as opposed to mono-functional alkylation, was selectively removed; the time-scale of this effect suggests an enzymic rather than a chemical mechanism. 6. The sensitive strain B(s-1) removed alkyl groups from DNA in this way only at very low extents of alkylation. When sensitized to mustard action by treatment with iodoacetamide, acriflavine or caffeine, the extent of alkylation of cellular DNA corresponding to a mean lethal dose was decreased to approximately 3 molecules of di(guanin-7-ylethyl) sulphide in the genome of this strain. 7. Relatively large numbers of monofunctional alkylations per genome can be withstood by this sensitive strain. Iodoacetamide had the weakest cytotoxic action of the agents investigated; methyl methanesulphonate was significantly weaker in effect than the monofunctional sulphur mustard, which was in turn weaker than the difunctional sulphur mustard. 8. Effects of the sulphur mustards on nucleic acid synthesis in sensitive and resistant strains were studied. DNA synthesis was inhibited in both strains at low doses in a dose-dependent manner, but RNA and protein synthesis were not affected in this way. 9. DNA synthesis in E. coli B(s-1) was permanently inhibited by low doses of mustards. In the resistant strains 15T(-) and B/r a characteristic recovery in DNA synthesis was observed after a dose-dependent time-lag. This effect could be shown at low doses in the region of the mean lethal dose. 10. Cellular DNA was isotopically prelabelled and the effect of mustards on stability of DNA was investigated. With resistant strains a dose-dependent release of DNA nucleotide material into acid-soluble form was found; this was much more extensive with the difunctional mustard (about 400 nucleotides released per DNA alkylation) than with the monofunctional mustard (about 10 nucleotides per alkylation). With the sensitive strain no dose-dependent release was found, though the DNA was less stable independent of cellular alkylation. 11. The results are discussed in terms of the concepts that alkylation of cellular DNA induces lesions which interfere with DNA replication, but which can be enzymically ;repaired'. The possible nature of these lesions is discussed in terms of the known reactions of the alkylating agents with DNA.

Alkylating Agents↗
PubMed1986

Alkylating agents: in vitro studies of cross-resistance patterns in human cell lines.

The alkylating agents represent one of the most important classes of antitumor agents and play a major role in combination with other agents in the curative chemotherapy of selected human cancers. By repeatedly exposing cells to escalating doses of an alkylating agent, we have developed four human tumor cell lines which are relatively stably resistant to the drug with which the culture was treated. The response of these cell lines to a variety of alkylating agents was compared to the response of the parent cell lines to the same drug. The Raji/HN2 line was 7-fold resistant to nitrogen mustard and about 3-fold resistant to 4-hydroxyperoxycyclophosphamide, but it was not resistant to N,N'-bis(2-chloroethyl)-N-nitrosourea (BCNU), melphalan (MEL), busulfan, trimethyleneiminethiophosphoramide, 4-hydroperoxyifosfamide, or cisplatin [cis-diamminedichloroplatinum(II)] (CDDP). The Raji/BCNU line was 5.3-fold resistant to BCNU and 4-fold resistant to both MEL and CDDP. The Raji/CP line was 7-fold resistant to CDDP and 3-fold resistant to both nitrogen mustard and BCNU, but it was not resistant to busulfan, trimethyleneiminethiophosphoramide, or 4-hydroperoxyifosfamide. The SCC-25/CP line, which was 12-fold resistant to CDDP, was 5-fold resistant to MEL and 3-fold resistant to 4-hydroxyperoxycyclophosphamide. The SCC-25/CP line was almost 24-fold resistant to methotrexate after 30-min treatment and about 7-fold resistant to methotrexate after continuous treatment. None of the other cell lines was resistant to methotrexate. The survival of SCC-25 and SCC-25/CP cells exposed to several antineoplastic agents was examined over several logs of survival. The SCC-25/CP cells are highly resistant to CDDP; the ratio of the slopes of the survival curves (SCC-25/CP to SCC-25) of the two lines was 43. At survivals of 1%, resistance to MEL and BCNU became evident in the SCC-25/CP line. At survivals of 0.1%, resistance to mitomycin C and, to a lesser degree, to Adriamycin and vincristine was evident. It is more difficult to produce resistance to alkylating agents, even with extended selection pressure, than to other antineoplastic drugs such as antimetabolites and natural products. We found no evidence of pleiotropic resistance in any alkylating agent-resistant cell line. Our results suggest that a judicious choice of alkylating agents given in sequential or concurrent combination may be a rational treatment strategy with potential applications in the clinic.

Alkylating Agents↗
PubMed2000

The alkaline single cell electrophoresis assay with eight mouse organs: results with 22 mono-functional alkylating agents (including 9 dialkyl N-nitrosoamines) and 10 DNA crosslinkers.

The genotoxicity of 22 mono-functional alkylating agents (including 9 dialkyl N-nitrosoamines) and 10 DNA crosslinkers selected from IARC (International Agency for Research on Cancer) groups 1, 2A, and 2B was evaluated in eight mouse organs with the alkaline single cell gel electrophoresis (SCGE) (comet) assay. Groups of four mice were treated once intraperitoneally at the dose at which micronucleus tests had been conducted, and the stomach, colon, liver, kidney, bladder, lung, brain, and bone marrow were sampled 3, 8, and/or 24 h later. All chemicals were positive in the SCGE assay in at least one organ. Of the 22 mono-functional alkylating agents, over 50% were positive in all organs except the brain and bone marrow. The two subsets of mono-functional alkylating agents differed in their bone marrow genotoxicity: only 1 of the 9 dialkyl N-nitrosoamines was positive in bone marrow as opposed to 8 of the 13 other alkylating agents, reflecting the fact that dialkyl N-nitrosoamines are poor micronucleus inducers in hematopoietic cells. The two groups of mono-functional alkylating agents also differ in hepatic carcinogenicity in spite of the fact that they are similar in hepatic genotoxicity. While dialkyl N-nitrosoamines produce tumors primarily in mouse liver, only one (styrene-7,8-oxide) out of 10 of the other type of mono-functional alkylating agents is a mouse hepatic carcinogen. Taking into consideration our previous results showing high concordance between hepatic genotoxicity and carcinogenicity for aromatic amines and azo compounds, a possible explanation for the discrepancy might be that chemicals that require metabolic activation show high concordance between genotoxicity and carcinogenicity in the liver. A high percent of the 10 DNA crosslinkers were positive in the SCGE assay in the gastrointestinal mucosa, but less than 50% were positive in the liver and lung. In this study, we allowed 10 min alkali-unwinding to obtain low and stable control values. Considering that DNA crosslinking lesions can be detected as lowering of not only positive but also negative control values, low control values by short alkali-treatment might make it difficult to detect DNA crosslinking lesions. In conclusion, although both mono-functional alkylating agents and DNA crosslinkers are genotoxic in mouse multiple organs, the genotoxicity of DNA crosslinkers can be detected in the gastrointestinal organs even though they were given intraperitoneally followed by the short alkali-treatment.

Alkylating Agents↗