The production of skeletal muscle atrophy and mammary tumors in rats by feeding 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide

Chronic toxicity and carcinogenicity of a food additive, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (AF-2) was examined by its oral administration to Wistar rats for 18 months. Male rats given 0.4% AF-2 diet developed ataxia of the hind foot around 4 months of feeding, and severe atrophy of skeletal muscles of the whole body was seen in 31 of 43 rats after 12 months. In female rats, mammary tumors developed in 78% of the animals given 0.4% AF-2 diet. Multiple papillomas were observed in the forestomach.     

Safety evaluation of chicken breast extract containing carnosine and anserine.

Chicken breast extract (CBEX) is obtained via hot water extraction of chicken breast and contains among its primary constituents carnosine and anserine, which are histidine-containing dipeptides present in the muscle tissues of most vertebrate species. Dietary intake of CBEX has been previously shown to buffer hydrogen ions formed during high-intensity exercise in human skeletal muscle cells, thereby inhibiting a decrease in muscle cell pH and subsequent muscle fatigue. The objective of this paper is to report the results of safety studies completed on CBEX. CBEX was determined to have an oral LD(50) value of more than 6000 mg/kg body weight in rats. Gavage doses of 500 or 2000 mg CBEX/kg body weight/day administered to rats for 90 days produced no toxicologically significant, dose-related, differences between control and treated animals with respect to body weight gain, food consumption, behavioral effects, hematological and clinical chemistry parameters, absolute and relative organ weights, or gross and microscopic findings. In the presence or absence of metabolic activation, CBEX exerted no mutagenic activity in the Ames assay conducted in various strains of Salmonella typhimurium and Escherichia coli. The results of these studies support the safety of CBEX as a potential dietary source of carnosine and anserine.     

Oral subchronic and genotoxicity studies conducted with the amino acid, l-glutamine

l-Glutamine is an abundantly occurring amino acid that serves numerous nutritional and physiological functions. It has current and potential applications as a therapeutic agent, dietary supplement, food ingredient, and in animal nutrition. To assess the safety of supplemental l-glutamine, a bacterial reverse mutation assay, in vitro chromosomal aberration assay, and a 13-week toxicity study were conducted. l-Glutamine showed no mutagenic activity in the bacterial reverse mutation assay, and did not induce chromosomal aberrations in Chinese hamster lung fibroblast cells in the in vitro chromosomal aberration assay. In the 13-week toxicity study, Sprague-Dawley rats (10/sex/group) were fed diets containing 0, 0.5, 2.5, or 5.0% l-glutamine. No deaths occurred, and no significant differences in body weights, body weight gains, ophthalmological findings, urinalysis parameters, or organ weights were observed between l-glutamine-fed rats and their respective controls. No toxicologically relevant effects on hematological or blood biochemical parameters were observed. Macroscopic and microscopic effects occurred at low frequency but were not associated with a dose-response relationship. Based on the results of the study, the no-observed-adverse-effect-level was determined to be 5.0% l-glutamine in the diet, the highest concentration tested (equivalent to 3832 and 4515 mg/kg body weight/day in male and female rats, respectively).     

Cis-trans isomerization of the (5-nitro-2-furyl)acrylamide, AF-2, initiated by ascorbate, glutathione, Fe(II) and OH-

The cis-trans isomerization of the (5-nitro-2-furyl)acrylamide, AF-2, has been investigated using some important biological reducing agents to initiate reaction. Physiological concentrations of L-ascorbic acid, glutathione and iron(II) all accomplish isomerization in a catalytic manner over a period of minutes. Base-catalysed isomerization has also been observed. In all cases, the presence of oxygen severely inhibits isomerization. It is proposed that the mechanism involves a free-radical chain process; AF-2 or analogues are thus extremely sensitive probes for the generation of nitro radicals in biochemical reducing systems because of the high efficiency of isomerization.     

Genotoxicity of pyrroloquinoline quinone (PQQ) disodium salt (BioPQQ™)

The genotoxic potential of pyrroloquinoline quinone (PQQ) disodium salt (BioPQQ™) was evaluated in a battery of genotoxicity tests. The results of the bacterial mutation assay (Ames test) were negative. Weak positive results were obtained in 2 separate in vitro chromosomal aberration test in Chinese hamster lung (CHL) fibroblasts. Upon testing in an in vitro chromosomal aberration test in human peripheral blood lymphocytes, no genotoxic activity of PQQ was noted. In the in vivo micronucleus assay in mice, PQQ at doses up to 2000 mg/kg body weight demonstrated that no genotoxic effects are expressed in vivo in bone marrow erythrocytes. The weak responses in the in vitro test CHL cells were considered of little relevance under conditions of likely human exposure. PQQ disodium was concluded to have no genotoxic activity in vivo.     

国产荧光素钠注射液中杂质的检测及结构鉴定

目的对国产荧光素钠注射液中的杂质进行分离及结构鉴定。方法采用RP HPLC法对荧光素钠注射液进行成分分析并用硅胶柱色谱法对主要杂质进行分离,根据质谱和核磁共振谱数据进行结构鉴定。结果和结论荧光素钠注射液中含有6羟基7磺酸基9(邻羧基苯基)3H口占吨3酮、6羟基9(邻乙氧基羰基苯基)3H口占吨3酮和2(2,4二羟基苯甲酰基)苯甲酸等杂质。     

Characterization of the microsomal cytochrome p-450 species induced in rat liver by trans-stilbene oxide

trans-Stilbene oxide differs from the classical inducers of drug-metabolizing enzymes, pheno-barbital and 3-methylcholanthrene, in that it induces the so-called phase II activities, epoxide hydrolase and glutathione S-transferase, to a much larger extent than it induces cytochrome P-450. Nonetheless, the level of cytochrome P-450 in liver microsomes from rats treated with trans-stilbene oxide is increased significantly to twice the control value.The existence of a number of different isozymes of cytochrome P-450 has now been clearly demonstrated and in the present study we have posed the question: What form(s) of cytochrome P-450 is induced by trans-stilbene oxide? A number of criteria including substrate specificity, pattern of benzo(a)pyrene metabolism, sensitivity to inhibitors, substrate binding spectra, ethylisocyanide binding spectra, sodium dodecyi sulfate-polyacrylamide gel electrophoresis, and crossed immunoelectrophoresis were used to answer this question. It seems clear that trans-stilbene oxide induces the same form(s) of cytochrome P-450 as phenobarbital.     

Measurement of glycidol hemoglobin adducts in humans who ingest edible oil containing small amounts of glycidol fatty acid esters

Hemoglobin (Hb) adducts are frequently used to address and/or monitor exposure to reactive chemicals. Glycidol (G), a known animal carcinogen, has been reported to form Hb adducts. Here, we measure G adduct levels in humans who daily ingest DAG oil, an edible oil consisting mainly of diacylglycerol. Since DAG oil contains a small amount of glycidol fatty acid esters (GEs), possible exposure to G released from GEs has been raised as a possible concern. For measurement of Hb adducts, we employed the N-alkyl Edman method reported by Landin et al. (1996) using gas chromatography-tandem mass spectrometry with minor modifications to detect G-Hb adducts as N-(2,3-dihydroxy-propyl)valine (diHOPrVal). Blood samples were collected from 7 DAG oil users and 6 non-users, and then G-Hb adduct levels were measured. G-Hb adducts were detected in all samples. The average level of diHOPrVal was 3.5 ± 1.9 pmol/g globin in the DAG oil users and 7.1 ± 3.1 pmol/g globin in the non-users. We conclude that there is no increased exposure to G in individuals who daily ingest DAG oil.     

1-(3-(9H-Carbazol-9-yl)-1-propyl)-4-(2-methoxyphenyl)-4-piperidinol,a novel subtype selective inhibitor of the mouse type II GABA-transporter

The selectivity of new derivatives of the γ-aminobutyric acid (GABA)-uptake inhibitor, tiagabine was characterized at the four cloned mouse GABA transporters (mGAT1 through mGAT4) by measuring [³H]-GABA uptake into stably transfected baby hamster kidney cells. While tiagabine is a highly selective inhibitor of mGAT1 (K_i=0.11±0.02 μM), these derivatives exhibited low potencies at mGAT1 but differential activities at mGAT2, mGAT3 and mGAT4. In particular, 1-(3-(9H-carbazol-9-yl)-1-propyl)-4-(2-methoxyphenyl)-4-piperidinol (NNC 05-2090) was a potent inhibitor of mGAT2 (K_i=1.4±0.3 μM) showing at least 10 fold selectivity over mGAT1, mGAT3 and mGAT4. NNC 05-2090 is the first subtype selective inhibitor of mGAT2 and may represent a novel useful tool for investigating the physiological roles of GAT2 in the brain and periphery.     

DNA methylation analysis in rat kidney epithelial cells exposed to 3-MCPD and glycidol

3-Monochloropropane-1,2-diol (3-MCPD) is a well-known food processing contaminant that has been regarded as a rat carcinogen, which is known to induce Leydig-cell and mammary gland tumors in males, as well as kidney tumors in both genders. 3-MCPD is highly suspected to be a non-genotoxic carcinogen. 2,3-Epoxy-1-propanol (glycidol) can be formed via dehalogenation from 3-MCPD. We aimed to investigate the cytotoxic effects of 3-MCPD and glycidol, then to demonstrate the possible epigenetic mechanisms with global and gene-specific DNA methylation in rat kidney epithelial cells (NRK-52E). IC₅₀ value of 3-MCPD was determined as 48?mM and 41.39?mM, whereas IC₅₀ value of glycidol was 1.67?mM and 1.13?mM by MTT and NRU test, respectively. Decreased global DNA methylation at the concentrations of 100?μM and 1000?μM for 3-MCPD and 100?μM and 500?μM for glycidol were observed after 48?h exposure by using 5-methylcytosine (5-mC) ELISA kit. Methylation changes were detected in promoter regions of c-myc and Rassf1a in 3-MCPD and glycidol treated NRK-52E cells by using methylation-specific PCR (MSP), whereas changes on gene expression of c-myc and Rassf1a were observed by using real-time PCR. However, e-cadherin, p16, VHL and p15 genes were unmethylated in their CpG promoter regions in response to treatment with 3-MCPD and glycidol. Alterations in DNA methylation might be key events in the toxicity of 3-MCPD and glycidol.     

9-［2-(膦酰甲氧基)乙基］腺嘌呤一钠盐在比格犬体内的毒代动力学和毒理学研究

目的 为9-［2-(膦酰甲氧基)乙基］腺嘌呤一钠盐（PMEA-Na）重复给药的毒性研究提供毒代动力学资料。方法 采用液相色谱质谱联用方法测定样品中的药物浓度，数据经统计矩方法处理得到毒代动力学参数，并完成血清生化学及组织病理学检测。结果 比格(Beagle)犬静脉单次及多次给药（14 d，每日1次）后，在给药剂量范围内，AUC均表现为剂量依赖性。在1.0, 3.0 与6.0 mg·kg^-1 PMEA-Na时，AUC分别为（2.3±0.5），（8.4±1.6），（17.5±3.7）mg·L^-1·h(单剂量)和（5.0±0.4），（15.9±3.2），(30.3±4.7) mg·L^-1·h（多剂量）。PMEA-Na主要经肾脏排出体外，且给药14 d后肾功能受损药物排泄能力降低。与对照组比较, 6.0 mg·kg^-1组血清生化学检测指标丙氨酸氨基转换酶、总胆红素、尿素氮、肌酐及甘油三酯均升高, 葡萄糖水平下降。6.0 mg·kg^-1组的组织病理学检查发现肝脏和肾脏有明显的病理形态学改变。结论 比格犬经静脉多次给PMEA-Na 14 d后出现毒性反应，毒性靶器官主要为肾脏和肝脏。     

The effect of alkylating agents and other drugs on the accumulation of melphalan by murine L1210 leukaemia cells in vitro

The effect of cytotoxic and other drugs on the accumulation of melphalan by L1210 murine leukaemia cells was studied. We have confirmed that uptake is an active process competitively inhibited by l-leucine. In 36 experiments in amino acid-free medium the mean concentration of melphalan taken up was 225 pmoles/10⁶ cells. High pressure liquid Chromatographie analysis showed that the majority of the drug is present as free native melphalan. 1, 3-Bis(2-chloroethyl)-1-nitrosourea (BCNU) was the only drug that stimulated accumulation, but without significant effect on influx or efflux rates. Busulphan, chlorambucil, cyclophosphamide, interferon, methotrexate and prednisolone had no effect on accumulation after 30 min melphalan transport. Adriamycin, CCNU, methyl CCNU, mustine and vincristine all impaired melphalan accumulation as did the non-cytotoxic drugs aminophylline, chlorpromazine and ouabain. Adriamycin, aminophylline, chloropromazine, indomethacin and ouabain all reduced melphalan influx.     

Enantioselective synthesis of tri-deuterated (–)-geosmin to be used as internal standard in quantitation assays

For the accurate and sensitive quantitation of the off-flavor compound geosmin, particularly in complex matrices, a stable isotopologue as internal standard is highly advantageous. In this work, we present a versatile synthetic strategy leading from (4aR)-1,4a-dimethyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one to tri-deuterated (–)-geosmin ((4S,4aS,8aR)-4,8a-dimethyl(3,3,4-²H₃)octahydronaphthalen-4a(2H)-ol). The starting material was readily accessible from inexpensive 2-methylcyclohexan-1-one using previously published procedures.     

9-[2-(膦酰甲氧基)乙基]腺嘌呤一钠盐在比格犬体内的毒代动力学和毒理学研究

目的为9-[2-(膦酰甲氧基)乙基]腺嘌呤一钠盐(PMEA-Na)重复给药的毒性研究提供毒代动力学资料。方法采用液相色谱质谱联用方法测定样品中的药物浓度,数据经统计矩方法处理得到毒代动力学参数,并完成血清生化学及组织病理学检测。结果比格(Beagle)犬静脉单次及多次给药(14 d,每日1次)后,在给药剂量范围内, AUC均表现为剂量依赖性。在1.0, 3.0与6.0 mg·kg-1PMEA-Na时,AUC分别为(2.3±0.5),(8.4±1.6),(17.5±3.7)mg·L-1·h(单剂量)和(5.0±0.4),(15.9±3.2),(30.3±4.7) mg·L-1·h(多剂量)。PMEA-Na主要经肾脏排出体外,且给药14 d后肾功能受损药物排泄能力降低。与对照组比较, 6.0 mg·kg-1组血清生化学检测指标丙氨酸氨基转换酶、总胆红素、尿素氮、肌酐及甘油三酯均升高,葡萄糖水平下降。6.0 mg·kg-1组的组织病理学检查发现肝脏和肾脏有明显的病理形态学改变。结论比格犬经静脉多次给PMEA-Na 14 d后出现毒性反应,毒性靶器官主要为肾脏和肝脏。     

“8204”对心血管系统和支气管平滑肌的药理作用

“8204”是新合成的化合物。动物实验表明:可使冠脉流量增加,心肌耗氧置降低,提高动物常压和低压情况下的缺氧耐力;对垂体后叶素诱发的缺血性心电图有保护作用,还能松弛离体豚鼠气管平滑肌,对抗乙酰胆碱和组胺引起的气管、支气管平滑肌收缩,增加豚鼠肺灌流量;对豚鼠吸入组胺引起的哮喘有明显保护作用。这些结果提示“8204”对治疗心肌缺血和支气管哮喘是有益的。     

RP-HPLC法测定家兔血浆中甲苯喹哌浓度和药代动力学参数

本文建立了以紫外230nm波长检测的反相高效液相色谱法(RP-HPLC)测定家兔血浆中甲苯喹派浓度。填料使用LiChrosorb RP-C18,流动相为甲醇—水—三乙胺—磷酸(63:37:1:0.8 v/v),血样(或尿样)经碱化后用乙醚提取,再以0.2 mol/L硫酸回提,进样。方法回收率为99.84±3.10(SD)%;天内、天间精密度平均CV为4.12%及3.95%(n=5);最低检测限3ng.经提取的标准线性浓度在25～2000 ng/ml范围内,Y=0.002865X-0.01346,r=0.9999,内源性物质及可能的合并用药不干扰色谱测定。文内用质谱法鉴定血样中甲苯喹哌色谱峰纯度,并由尿样分析对其主要代谢物予以初步验证。本法可应用于药代动力学参数测定。家兔按8mg/kg静注后,药—时曲线符合二室模型T_1/2=4.8008±1.1522(SD)h。     

Stereoselective monooxygenation of carcinostatic 1-(2-chloroethyl)-3-(cyclohexyl)-1-nitrosourea and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea by purified cytochrome P-450 isozymes

Three highly purified forms of liver microsomal cytochrome P-450 (P-450a, P-450b and P-450c) from Aroclor 1254-treated rats catalyzed 1-(2-chloroethyl)-3-(cyclohexyl)-1-nitrosourea (CCNU) and 1-(2-chloroethyl)-3-(trans-4-methylcyclohexyl)-1-nitrosourea (MeCCNU) monooxygenation in the presence of purified NADPH-cytochrome P-450 reductase, NADPH, and lipid. Differences in the regioselectivity of CCNU and MeCCNU monohydroxylation reactions by the cytochrome P-450 isozymes were observed. Cytochrome P-450-dependent monooxygenation of CCNU gave only alicyclic hydroxylation products, but monooxygenation of MeCCNU gave alicyclic hydroxylation products, an αhydroxylation product on the 2-chloroethyl moiety, and a trans-4-hydroxymethyl product. A high degree of stereoselectivity for hydroxylation of CCNU and MeCCNU at the cis-4 position of the cyclohexyl ring was demonstrated. All three cytochrome P-450 isozymes were stereoselective in primarily forming the metabolite cis-4-hydroxy-trans-4-Methyl-CCNU from MeCCNU. The principal metabolite of CCNU which resulted from cytochromes P-450a and P-450b catalysis was cis-4-hydroxy CCNU, whereas the principal metabolites from cytochrome P-450c catalysis were the trans-3-hydroxy and the cis-4-hydroxy isomers. Total amounts of CCNU and MeCCNU hydroxylation with cytochrome P-450b were twice that with hepatic microsomes from Aroclor 1254-treated rats. Catalysis with cytochromes P-450a and P-450c was substantially less effective than that observed with either cytochrome P-450b or hepatic microsomes from Aroclor 1254-treated rats.     

血吸虫病化学治疗的研究 ⅩⅩⅩⅥ.4-苯基(或烯丙基)-5-(吡嗪-2)-1,2,4-三唑-3-硫酮衍生物的合成

本文报导28个4-苯基(或烯丙基)-5-(吡嗪-2)-1,2,4-三唑-3-硫酮衍生物的合成。这类化合物的合成是以吡嗪甲酸乙酯与水合肼反应得2-吡嗪甲酰肼,再与不同的异硫氰酸酯作用后,在2N氢氧化钠溶液中环合而得Ⅱ或Ⅲ,然后经烷化、酰化及Mannich反应,分别制得相应的化合物。其中Ⅲ₁和Ⅲ₂对感染日本血吸虫小白鼠有明显肝移作用。