The Development of an Extraction Method for Simultaneously Analyzing Fatty Acids in Macroalgae Using SPE with Derivatization for LC-MS/MS.

Fatty acid analysis is an essential step in evaluating the potential of macroalgae for biodiesel production. An extraction method was developed to simultaneously analyze up to five types of biodiesel-fuel-related fatty acids (myristic acid, palmitic acid, cis-palmitvaccenic acid, stearic acid, and oleic acid) in macroalgae using liquid chromatography and tandem mass spectrometry (LC-MS/MS). Lypophilization and solid-phase extraction (SPE) techniques were applied to improve the extraction efficiency and effectively purify samples. The optimal conditions for SPE were set by comparing the recoveries according to the various solvent conditions for each step (loading, washing, and elution). In addition, the introduction of trimethylaminoethyl (TMAE) derivatives to the hydroxyl group of the target analyte increased the ionization efficiency and sensitivity. The derivatized samples were analyzed using the LC-MS/MS method with electrospray ionization in the positive and multiple-reaction monitoring modes. The target analytes were separated and detected within 13.5 min using a CAPCELL PAK C18 MGII S3 column. Gradient elution was performed using distilled water and acetonitrile containing 5 mM ammonium acetate. This method offers a reliable and sensitive tool for the analysis of macroalgae samples for their potential use in biodiesel production. To the best of our knowledge, this is the first report on the simultaneous determination of fatty acids in macroalgae using LC-MS/MS with TMAE derivatization.

Ganoderma adspersum (Ganodermataceae): Investigation of Its Secondary Metabolites and the Antioxidant, Antimicrobial, and Cytotoxic Potential of Its Extracts.

Ganoderma is a genus of wood-degrading mushrooms with medicinal importance. Most Ganoderma species have been studied extensively for their secondary metabolites, biological activities, and ecological value. In this study, the biological activities of the extracts of G. adspersum growing wild on Morus alba trees in the region of Western Thrace (Greece) were evaluated, and the petroleum ether, dichloromethanolic, and methanolic extracts were studied further for their secondary metabolites. Six substances were isolated by chromatographic (Clumn Chromatography (C.C.), High Performance Liquid Chromatography (HPLC)) and spectroscopic methods (Nuclear Magnetic Resonance (NMR)), which were classified in the following categories: (a) unsaturated fatty acids: cis-oleic acid (1); (b) sterols: ergosta-7,22-dien-3-one (2), ergosta-7,22-dien-3-ol (3), and ergosta-5,7,22-trien-3-ol (4); and (c) lanostane-type triterpenoids: applanoxidic acid G (5) and applanoxidic acid A (6). Finally, the biological activities of the extracts were estimated for their antioxidant, antimicrobial, and cytotoxic potential. The methanolic extract of G. adspersum showed the highest total antioxidant activity. The results of the antimicrobial activities indicated that all of the extracts had a minimum inhibitory concentration (MIC) ranging between 39.1 and 312.5 µg/mL. The evaluation of the cytotoxic activity of the samples showed once again that the methanolic extract was the most potent among the examined extracts, with half-maximal inhibitory concentration (IC50) values of 19.22 µg/mL (Hep2c cells), 32.9 µg/mL (RD cells), and 8.94 µg/mL (L2OB cells). Moreover, the bioactivity scores of the isolated secondary metabolites were calculated using the online computer software program Molinspiration. The compounds showed promising bioactivity scores for drug targets.

LC-MS-based urine metabolomics analysis of chronic subdural hematoma for biomarker discovery.

BACKGROUND: Chronic subdural hematoma (CSDH) is one of the most common neurosurgical diseases with atypical manifestations. The aim of this study was to utilize urine metabolomics to explore potential biomarkers for the diagnosis and prognosis of CSDH. METHODS: Seventy-seven healthy controls and ninety-two patients with CSDH were enrolled in our study. In total, 261 urine samples divided into the discovery group and validation group were analyzed by LC-MS. The statistical analysis and functional annotation were applied to discover potential biomarker panels and altered metabolic pathways. RESULTS: A total of 53 differential metabolites were identified in this study. And the urinary metabolic profiles showed apparent separation between patients and controls. Further functional annotation showed that the differential metabolites were associated with lipid metabolism, fatty acid metabolism, amino acid metabolism, biotin metabolism, steroid hormone biosynthesis, and pentose and glucuronate interconversions. Moreover, one panel of Capryloylglycine, cis-5-Octenoic acid, Ethisterone, and 5,6-DiHETE showed good predictive performance in the diagnosis of CSDH, with an AUC of 0.89 in discovery group and an AUC of 0.822 in validation group. Another five metabolites (Trilobinol, 3'-Hydroxyropivacaine, Ethisterone, Arginyl-Proline, 5-alpha-Dihydrotestosterone glucuronide) showed the levels of them returned to a healthy state after surgery, showing good possibility to monitor the recovery of CSDH patients. CONCLUSION AND CLINICAL RELEVANCE: The findings of the study revealed urine metabolomic differences between CSDH and controls. The potentially diagnostic and prognostic biomarker panels of urine metabolites were established, and functional analysis demonstrated deeper metabolic disorders of CSDH, which might conduce to improve early diagnose of CSDH clinically.

Structural identification and antioxidant activity of trans-9, trans-11, cis-15-conjugated linolenic acid converted by probiotics.

The study aimed to determine the chemical structures of octadecatrienoic acid isomers produced by probiotics through the bioconversion of α-linolenic acid and to assess their antioxidant capacities. The chemical structures were identified using nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS), while the antioxidant capacities were evaluated in vitro and in cellular. The NMR signals obtained allowed for definitive characterization, with the main ion fragments detected being m/z 58.0062, 59.0140, 71.0141, 113.0616, 127.0777, and 181.5833. Compounds at concentrations below 40 µM maintained the antioxidant capacity of HepG2 cells by protecting endogenous antioxidative enzymes and mitochondrial membrane potential. However, doses higher than 40 µM increase oxidative damage and mitochondrial dysfunction. These results confirmed the structure of the probiotic-derived compound as trans9, trans11, cis15-conjugated linolenic acid. Additionally, appropriate doses of CLNA can alleviate oxidative stress induced by AAPH, while high doses aggravate cellular damage. These findings provide foundational information for the further exploration of probiotic-derived edible lipids.

Nitroxyl radicals as low toxic spin-labels for non-invasive magnetic resonance imaging of blood-brain barrier permeability for conventional therapeutics.

The present study describes a novel non-radioactive methodology for in vivo non-invasive, real-time imaging of blood-brain barrier (BBB) permeability for conventional drugs, using nitroxyl radicals as spin-labels and magnetic resonance imaging (MRI).

Effect of the spin-labelled 1-ethyl-1-nitrosourea on CCNU-induced oxidative liver injury.

This study was carried out to determine the effects of 1-ethyl-3-[4-(2,2,6,6-tetramethylpiperidine-1-oxyl)]-l-nitrosourea (SLENU), recently synthesised in our laboratory, and vitamin E as positive control on 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) - free radical induced oxidative injuries in the liver of mice. Specifically, alterations in malonyl dialdehyde (MDA) level and activities of some antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), were measured in liver homogenates from tumour-bearing C57 black mice after treatment with solutions of CCNU (30 mg/kg) and SLENU (100 mg/kg), both administered intraperitoneally. CCNU-induced increase in MDA level, SOD and CAT activities were suppressed by SLENU. The present results and those from a previous report demonstrated superoxide scavenging activities (SSA) of the nitrosourea SLENU and enabled us explain the protective effect of the spin-labelled nitrosourea on CCNU-induced oxidative stress in the liver of mice. This protective effect is through the scavenging of *O2- and by an increased production of *NO. Thus, a potential for developing new combination chemotherapy in cancer is seen.

2-Chloroethyl (methylsulfonyl)methanesulfonate (NSC-338947), a more selective DNA alkylating agent than the chloroethylnitrosoureas.

The novel chloroethylating agent 2-chloroethyl (methylsulfonyl)methanesulfonate (CIEtSoSo) has been shown to act like the chloroethylnitrosoureas (CIEtNu's) in its DNA damaging and cytotoxic effects in human cell lines and has similar activity to the CIEtNu's in the National Cancer Institute antitumor screening tests. Its simpler chemistry, however, suggests that it may alkylate DNA more selectively than do the CIEtNu's. The DNA base adducts produced in calf thymus DNA by CIEtSoSo have been compared to a representative, non-carbamoylating CIEtNu, 1-(2-chloroethyl)-3-(cis-2-OH)cyclohexyl-1-nitrosourea, using high-pressure liquid chromatography. Two major modified base peaks were observed from the nitrosourea treated sample which have been subsequently identified by high-pressure liquid chromatography comparison of synthesized standards and by electron impact gas chromatography/mass spectrometric analysis to be 7-hydroxyethylguanine and 7-chloroethylguanine. In contrast only 7-chloroethylguanine was obtained from the CIEtSoSo treated DNA at equimolar doses. Thus CIEtSoSo was found to be more specific in its reaction with DNA in that it produced less variety of products than the nitrosourea, with no apparent generation of hydroxyethyl products, which are major side reactions of the CIEtNu's.

DNA sequence selectivity of guanine-N7 alkylation by three antitumor chloroethylating agents.

The DNA sequence selectivities of guanine-N7 alkylation produced by three chloroethylating antitumor agents, 1-(2-chloroethyl)-3-(cis-2-hydroxy) cyclohexyl-1-nitrosourea (cis-2-OH CCNU), 2-chloroethyl (methylsulfonyl)methanesulfonate, and 8-carbamoyl-3-(2-chloroethyl)imidazo-[5,1-d]-1,2,3,5-tetrazin-4(3H )-one (mitozolomide), were examined using a modification of the Maxam and Gilbert sequencing technique. In a region of pBR322 DNA, 2-chloroethyl (methylsulfonyl)methanesulfonate produced approximately the same degree of alkylation at all guanines. cis-2-OH CCNU, however, preferentially alkylated the middle guanines in runs of three or more guanines; the intensity of the reaction increased with the number of adjacent guanines in the DNA sequence. Mitozolomide produced the same pattern of preferential alkylation but not as intensely as cis-2-OH CCNU. Three other nitrosoureas, 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea, 1-(2-fluorethyl)-3-cyclohexyl-1-nitrosourea, and 1-(2-chloroethyl)-1-nitrosourea gave similar patterns of alkylation to that of cis-2-OH CCNU at pH 7.2. The ratio of 7-hydroxyethylguanine to 7-chloroethylguanine was approximately the same following treatment of the synthetic polymers dGn X dCn and (dG X dC)n with cis-2-OH CCNU, indicating that 7-chloroethylation and 7-hydroxyethylation were enhanced similarly by the presence of adjacent guanines. Ethylnitrosourea produced relatively little alkylation preference. The results suggest that the alkylating intermediates, 2-chloroethyldiazohydroxide and 2-hydroxyethyldiazohydroxide, tend to react preferentially with those guanine-N7 positions the electronegativity of which is enhanced by the presence of neighboring guanines. This is consistent with the presence of cationic character in the alkylating centers of these intermediates. 2-Chloroethyl (methylsulfonyl)methanesulfonate and ethyldiazohydroxide would not be expected to have strong cationic character, in agreement with their lack of sequence selectivity.

Prevention of 1-(3-deoxycytidyl),2-(1-deoxyguanosinyl)ethane cross-link formation in DNA by rat liver O6-alkylguanine-DNA alkyltransferase.

Previous studies have shown that the haloethylnitrosoureas introduce the cross-link 1-(3-deoxycytidyl),2-(1-deoxyguanosinyl)ethane into DNA. This structure is evidently formed by the following sequence of events: an initial attack of a haloethyl group on the O6 position of guanine, formation of the reactive intermediate, 1,O6-ethanoguanine, and reaction of this intermediate with deoxycytidine in the opposite DNA strand. To investigate the role of O6-alkylguanine-DNA alkyltransferase in preventing the formation of this cross-link, a DNA substrate containing O6-fluoroethylguanine has been prepared by reacting DNA with N-2-fluoroethyl-N'-cyclohexyl-N-nitrosourea. The O6-fluoroethylguanine content of this substrate decreases when it is incubated at 37 degrees C and pH 7.8 in the absence of repair factors because of the chemical instability of O6-fluoroethylguanine; however, this loss is accelerated by the addition of rat liver O6-alkylguanine-DNA alkyltransferase, indicating that this repair factor recognizes and repairs O6-fluoroethylguanine in DNA; furthermore, by using [chloroethyl-14C]N-chloroethyl-N'-cyclohexyl-N-nitrosourea, it can be shown directly that the addition of rat liver O6-alkylguanine-DNA alkyltransferase prevents 1-(3-deoxycytidyl),2-(1-deoxyguanosinyl)ethane formation. These studies link the presence of repair activity to the prevention of a specific cytotoxic lesion in DNA.

Mechanism of uptake of nitrosoureas by L5178Y lymphoblasts in vitro.

The mechanism of uptake of nitrosoureas by L5178Y cells in vitro was investigated. A time course of the uptake of radioactivity on incubation of L5178Y lymphoblast with [14C]-1,3-bis(2-chloroethyl)-1-nitrosourea was linear for 30 min and then entered a plateau phase; it was markedly temperature dependent. A similar time course for cells incubated with [14C]ethylene-labeled 1-(2-chlorethyl)-3-cyclohexyl-1-nitrosourea reached equilibrium rapidly, was temperature independent, and resulted in a relatively low level of uptake of radioactivity. However, cells treated with 3-[cyclohexyl-14C]-1-(2-chlorethyl)-1-nitrosourea had a time course that was linear for 30 min, resulted in much higher levels of uptake of radioactivity, and was strongly temperature dependent. These findings, at least for 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea, suggest that some drug decomposition precedes uptake. The percentage of radioactivity found in the cell sap fraction was at least 85% of total cell activity when cells were incubated with any of the three 14C-labeled nitrosoureas. Furthermore, thin-layer chromatography of the cell sap fraction revealed the presence of free intact drug. These findings indicate that intracellular uptake of intact nitrosoureas occurred. A time course of uptake of intact 1,3-bis(2-chloroethyl)-1-nitrosourea reached equilibrium rapidly with cell/medium distribution ratios of 0.2 to 0.6 and was temperature independent. The addition of excess unlabeled 1,3-bis(2-chlorethyl)-1-nitrosourea or 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea had no effect on uptake of [14C]-1,3-bis(2-chloroethyl)-1-nitrosourea, These findings suggest that uptake of intact 1,3-bis(2-chloroethyl)-1-nitrosourea was by passive diffusion. A time course of the uptake of intact 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea with either [14C]ethylene- or ring-labeled drug rapidly reached equilibrium, was temperature independent, and attained a cell/medium ratio greater than unity. Uptake of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea was sodium independent and was unaffected by the metabolic inhibitors (sodium fluoride, sodium cyanide, or 2,4-dinitrophenol) or by urea, a potential physiological competitor. Furthermore, addition of unlabeled 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea or 1,3-bis(2-chlorethyl)-1-nitrosourea had no effect on uptake of labeled 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea. These findings suggest that uptake of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea also occurs by passive diffusion.

DNA-protein cross-linking and DNA interstrand cross-linking by haloethylnitrosoureas in L1210 cells.

Bifunctional alkylating agents are known to produce cross-links between DNA and protein and between paired DNA strands. The possibility of discriminating these two classes of cross-links in L1210 cells treated with haloethylnitrosoureas or nitrogen mustard was explored with the alkaline elution technique. Two classes of cross-links were demonstrated, based on sensitivity to proteinase K; the proteinase-sensitive cross-links appear to be DNA-protein cross-links, and the proteinase-resistant class may include interstrand cross-links. Proteinase-sensitive cross-links form more rapidly than do proteinase-resistant cross-links in cells treated with chloroethylnitrosoureas, perhaps because these agents can chloroethylate protein sulfhydryl or amino groups followed by rapid reaction of these chloroethylated groups with DNA. Although both types of cross-links produced by nitrogen mustard disappeared or were repaired after 24 hr, the removal of cross-links produced by chloroethylnitrosoureas either did not occur or was incomplete in 24 hr. In addition to cross-links, cells treated with haloethylnitrosoureas exhibited DNA strand breaks; a method is suggested for estimating the apparent frequencies of strand breaks and cross-links in the DNA.

Effects of carbamoylation on cell survival and DNA repair in normal human embryo cells (IMR-90) treated with various 1-(2-chloroethyl)-1-nitrosoureas.

The possibility was examined that the carbamoylating activity of some chloroethylnitrosoureas could interfere with the activity of normal human cells to survive treatment with these drugs; 1-(2-chloroethyl)-3-(trans-4-hydroxycyclohexyl)-1-nitrosourea, which has strong carbamoylating activity, inhibited the rejoining of drug or X-ray-induced DNA strand breaks in IMR-90 cells, whereas the noncarbamoylating cis-2-hydroxy isomer had little or no effect; 1-(2-chloroethyl)-3-(trans-4-hydroxycyclohexyl)-1-nitrosourea was twice as potent as the cis-2-hydroxy isomer in reducing colony survival. The moderate or high carbamoylating drugs 1,3-bis(2-chloroethyl)-1-nitrosourea and 1-(2-chloroethyl)-3-(cyclohexyl)-1-nitrosourea had effects resembling those of 1-(2-chloroethyl)-3-(trans-4-hydroxycyclohexyl)-1-nitrosourea. The low carbamoylating drug 1-(2-chloroethyl)-3-(2,6-dioxo-1-piperidyl)-1-nitrosourea had effects resembling those of the cis-2-hydroxy isomer. 1-(2-chloroethyl)-1-nitrosourea, although a strong carbamoylator in chemical systems, behaved biologically as if it were a low carbamoylator. This can be rationalized on the basis of limited cellular uptake of cyanate ion. The results suggest that carbamoylation may inhibit the nucleotide excision repair of chloroethylnitrosourea-induced DNA damage that may be crucial to the ability of normal human cells to recover from the action of these drugs. Previous work has indicated that susceptible human tumor cells are sensitive to chloroethylnitrosoureas because of a lack of a DNA repair protein (guanine O6-alkyltransferase) that is not involved in nucleotide excision repair. On the basis of these findings and other evidence, further clinical trials of appropriate noncarbamoylating chloroethylnitrosoureas would be justified.

Biological and biochemical properties of the 2-hydroxyl metabolites of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea.

The lethal and bone marrow toxicity and antitumor activity of the cis- and trans-2-hydroxylated metabolites of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) have been correlated with their relative in vitro alkylating and carbamoylating activities. Both the isomers have considerably greater alkylating activity and shorter chemical half-lives than the parent compound and on a molar basis have greater antitumor activity against i.p. L1210 leukemia. However, in terms of molar doses resulting in the death of 10% of normal mice, the cis- and trans-2 isomers were 2- and 3-fold more toxic than was CCNU in normal mice. In comparing the antitumor activity produced by a maximum nonlethal dose for each compound, we found that the trans isomer had activity identical to that of CCNU (413 and 410% increased life span compared to control), and the cis isomer had considerably less (152%). Like chlorozotocin, both isomers possess low carbamoylating activity and increased water solubility, two features that have been considered possible contributors to the bone marrow-sparing character of chlorozotocin. However, in the murine model the human bone marrow colony formation (CFU-C) assay neither hydroxylated metabolite of CCNU was associated with reduced myelotoxicity.

Synthesis and biologic evaluation of major metabolites of N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea.

N-(2-chloroethyl)-N'-(cis-4-hydroxycylohexyl)-N-nitrosourea, a major metabolite of N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea (CCNU), and its trans isomer were prepared from the corresponding 4-aminocyclohexanols. A convenient and stereospecific precursor was found in 2-oxa-3-azabicyclo[2.2.2]oct-5-ene hydrochloride, hydrogenation giving pure cis-4-aminocyclohexanol hydrochloride. The metabolites were, at nontoxic levels, at least as active as CCNU in tests against murine leukemia L1210 implanted both intraperitoneally and intracerebrally and, on a weight basis, were more active and more toxic. These observations and previously reported metabolic studies suggest that the anticancer activity of CCNU is due primarily to its metabolites.

cis-4-[[[(2-Chloroethyl)nitrosoamino]carbonyl]methylamino] cyclohexanecarboxylic acid, a nitrosourea with latent activity against an experimental solid tumor.

cis-4-[[[(2-Chloroethyl)nitrosoamino]carbonyl]methylamino] cyclohexanecarboxylic acid (N-Me-cis-CCCNU) was synthesized in five steps from cis-4-aminocyclohexanecarboxylic acid via an N-tosylated intermediate. N-Me-cis-CCCNU, which is incapable of the facile decomposition that characterizes the clinically useful nitrosoureas, effected a significant cure rate of both early and established murine Lewis lung carcinoma, even though its in vitro half-life was approximately 5.5 times that of the unmethylated parent compound. This is the first observation of latent activity of a nitrosourea against an experimental solid tumor.

Fluorinated analogues of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea: an attempt to control metabolism.

In seeking to block and thereby determine the role of the rapid in vivo hydroxylation of the cyclohexyl moiety of 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) in relation to antitumor activity and tissue distribution, the 3-(1H-decafluorocyclohexyl) analogue (FCCNU) was synthesized. FCCNU showed marked toxicity and little activity against the intracerebral L1210 leukemia in mice. At pH 7 in phosphate buffer at room temperature FCCNU rapidly decomposed to give 1-(1H-decafluorocyclohexyl)-3-nitrosoimidazolidin-2-one (3) and thence, by loss of HF, the 1-(nonafluorocyclohexenyl) derivative (4); CCNU did not follow this decomposition pathway to any significant extent. Both 3 and 4 were unstable in the buffer, but each was isolated crystalline and characterized. The formation of 3 and 4 account for the biological properties of FCCNU.

Role of fluroacetate in the toxicity of 2-fluroethylnitrosoureas.

The possible role of fluroacetate in the toxicity and antitumour activity of the fluroethylnitrosoureas, BFNU and FCNU has been studied in CBA mice bearing the TLX5 lymphoma either sensitive (TLXS) or resistant (TLXRT) to nitrosoureas. Treatment of mice bearing either TLXS or TLXRT tumours with either BFNU or FCNU caused an elevation in the citrate levels of heart, kidney and tumour, but not the liver, 24 hr after drug administration. Heart citrate levels were maximally elevated 10-fold, while the levels in kidney and tumour were increased 3- to 6-fold. Tissue levels of flurocitrate were determined by glc after conversion to the ethyl ester. This showed maximum levels of fluroacetate production in heart, with lower levels in kidney, tumour and liver. Treatment of K562 human erythroleukaemia cells in vitro with BFNU caused an inhibition in the production of 14CO2 from 14C palmitate and [U-14C] glucose. These results suggest that some of the effects of the fluroethylnitrosoureas may be related to fluroacetate production and the consequent blocking effect on aconitase. This effect is probably related more to the generalized toxicity of these agents than to their therapeutic efficacy.

Genotoxic effect of 4-aroyl-1-(2-chloroethyl)-1nitrosohydrazinecarboxamides on Saccharomyces cerevisiae cells.

The study of some 4-aroyl-1-(2-chloroethyl)-1-nitrosohydrazinecarboxamides with a Saccharomyces cerevisiae mutagenicity test of increased sensitivity defined two of them, 4-(4-bromobenzoyl)-1-(2-chloroethyl)-1-nitrosohydrazinecarboxam ide and 4-(4-fluorophenyl)-1-(2-chloroethyl)-1-nitrosohydrazine carboxamide as typical cytostatic agents. At concentrations of 2-5 microg/ml the substances kill up to 60%-70% of cells without having any detectable recombinogenic and mutagenic effects. At the same concentrations, lomustine, well known as a cytostatic reference, demonstrated recombinogenic and mutagenic activity on yeast cells. The advantage of the newly synthesized substances is that, in a certain concentration range, their biological activity is mainly cytotoxic without induction of recombinogenic and mutagenic events in surviving cells.

Clinical pharmacokinetics of oral CCNU (lomustine).

The plasma pharmacokinetics of orally administered CCNU (130 mg/m2) were studied in four patients using reversed-phase high-performance liquid chromatography (HPLC) analysis. Parent CCNU was not detected in the plasma of any of the patients, probably due to complete conversion to monohydroxylated metabolites during the 'first pass' through liver and gut. However, two monohydroxylated metabolites, trans-4-hydroxy CCNU and cis-4-hydroxy CCNU, were found at high concentrations, the relative amounts being about 6:4. Peak concentrations of the metabolites were reached 2-4 h after administration and were remarkably similar for all four patients, the total being 0.8-0.9 micrograms/ml. The metabolites were also detected in a tumour biopsy. Plasma clearance half-lives of the two metabolites were similar in each patient but showed a two-fold variation between patients, from 1.3 to 2.9 h. These results suggest that the antitumour activity and systemic toxicity of CCNU when given orally are due mainly to its monohydroxylated metabolites. Finally, comparison with data obtained in vitro and in mice showed that the nitrosourea exposures in these patients were at the lower limit of those required for significant antineoplastic activity.

MItomycin C, methyl-CCNU and 5-fluorouracil in the treatment of metastatic colorectal carcinoma.

The combination of mitomycin C, methyl-CCNU and 5-fluorouracil produced no objective tumor regressions in 25 evaluable patients with metastatic colorectal carcinoma. Patients who achieved stable disease survived significantly longer than patients who had progressive disease. This difference appeared to be more probably related to pre-treatment characteristics of the patients than caused by treatment. Serial CEA determinations revealed a parallel relationship with tumor behavior in 17 of 19 patients.