Genotoxic effects of N-nitrosoketamine and ketamine as assessed by in vitro micronucleus test in Chinese hamster lung fibroblast cell line

Objectives  Ketamine hydrochloride (KT) is a secondary amine that has been safely used as an injectable anesthetic and analgesic to avoid the production of nitroso compounds in the stomach. However, ketamine in the tablet form has recently become an abused, recreational drug. The aim of this study was to investigate the genotoxic effects of N-nitrosoketamine (NKT) and KT on the basis of an in vitro micronucleus (MN) test using a Chinese hamster lung fibroblast cell line (CHL/IU). Methods  NKT was synthesized from KT in our laboratory. In the MN tests, CHL/IU cells were continuously treated with either NKT or KT for 24, 48, or 72 hours without the S9 mix. The cells were also treated with NKT or KT with or without the S9 mix for 6 hours, followed by a recovery period of 18, 42, or 66 hours (short-term treatment). The results were considered to be statistically significant when the p-values of both Fisher’s exact test and the trend test were less than 0.05. Results  After the short-term treatment with either NKT or KT with and without the S9 mix, the frequency of micronuclei significantly increased. However, the frequency of micronuclei did not significantly increase after the continuous treatment with either NKT or KT. Both NKT and KT were determined to be genotoxic in the short-term treatment with or without the S9 mix, but they were determined to be nongenotoxic in continuous treatment. Conclusion  Our findings suggest that NKT has a stronger genotoxic effect than KT.     

The ADAMs family: coordinators of nervous system development, plasticity and repair

A disintegrin and metalloprotease (ADAM) transmembrane proteins have metalloprotease, integrin-binding, intracellular signaling and cell adhesion activities. In contrast to other metalloproteases, ADAMs are particularly important for cleavage-dependent activation of proteins such as Notch, amyloid precursor protein (APP) and transforming growth factor alpha (TGFalpha), and can bind integrins. Not surprisingly, ADAMs have been shown or suggested to play important roles in the development of the nervous system, where they regulate proliferation, migration, differentiation and survival of various cells, as well as axonal growth and myelination. On the eleventh anniversary of the naming of this family of proteins, the relatively unknown ADAMs are emerging as potential therapeutic targets for neural repair. For example, over-expression of ADAM10, one of the alpha-secretases for APP, can prevent amyloid formation and hippocampal defects in an Alzheimer mouse model. Another example of this potential neural repair role is the finding that ADAM21 is uniquely associated with neurogenesis and growing axons of the adult brain. This comprehensive review will discuss the growing literature about the roles of ADAMs in the developing and adult nervous system, and their potential roles in neurological disorders. Most excitingly, the expanding understanding of their normal roles suggests that they can be manipulated to promote neural repair in the degenerating and injured adult nervous system.     

单细胞凝胶电泳分析地黄提取物对仓鼠肺成纤维细胞DNA的损伤作用

目的 采用单细胞凝胶电泳（彗星实验）技术研究地黄提取物致仓鼠肺成纤维细胞（CHL细胞）DNA的损伤作用,为该药物临床前安全性评价提供参考。方法 采用0.2、1.0、5.0 mg/mL地黄提取物,用双氧水作为阳性对照药,处理细胞,24 h后收获细胞,进行彗星电泳实验。结果/b> 双氧水处理后造成CHL细胞产生明显的DNA损伤,呈现不同彗尾长度的彗星,与阴性对照组比较有显著差异。不同质量浓度的地黄提取物处理细胞后,彗星长、彗尾长度等各项指标与阴性对照组比较无显著差异。结论 单细胞凝胶电泳检测DNA损伤的敏感度较高,不同质量浓度的地黄提取物对CHL细胞未产生DNA损伤。     

Absence of subchronic oral toxicity and genotoxicity of rice koji with Aspergillus terreus

Koji products have been considered as an effective fermented food consumed in East Asia with many health benefits. Particularly, rice koji with Aspergillus terreus (RAT) has been reported to be able to prevent hyperlipidemia and hepatic steatosis through regulating cholesterol synthesis. Despite its biological activities, there is a lack of comprehensive information to give an assurance of its safety. Therefore, the objective of this study was to perform a series of toxicological studies (repeated dose oral toxicity and genotoxicity) according to test guidelines published by the Organization for Economic Cooperation and Development. Along with acute toxicity study using rats and beagle dogs, a 13-week toxicity study revealed no clear RAT-related toxic changes, including body weight, mortality, hematology, serum biochemistry, organ weight, and histopathology after oral administration at doses of 500, 1000, and 2000 mg/kg BW. The no-observed-adverse-effect level of RAT was considered to be more than 2000 mg/kg BW/day in rats of both genders. In addition, potential genotoxicity was evaluated using a standard battery of tests (Ames test, chromosome aberration assay, and micronucleus assay) which revealed that RAT showed no genotoxicity. Accordingly, these results suggest that RAT is a safe and non-toxic functional food for human consumption at proper dose.     

口腔卫生用品中甲硝唑的致突变检测及分析

验证加入口腔卫生品中的硝唑的遗传毒性。采用中国仓鼠肺成纤维细胞体外染色体畸变试验和胎鼠肝血嗜多染红细胞微试验对甲硝唑进行了检测。「结果」甲硝唑可引起ＣＨＬ细胞染色体的断裂、缺失和易位等结构异常,畸变率明显高于空白对照;各剂量组胎鼠肝血嗜多染红细胞微核率均高于对照组,中高高剂量组微核率与对照组相比差异有极显著性,且存在较为明显的量－反应关系。「结论」甲硝唑经肠胃吸收后,可透过胎盘屏障进入胎鼠,并造成     

Intestinal α-glucosidase inhibitory activity and toxicological evaluation of Nymphaea stellata flowers extract

Aim of the study

Nymphaea stellata willd. flowers (NSF) are used as a traditional medicine in India and Nepal to treat diabetic disease. Different works have demonstrated that NSF extract showed antihyperglycemic effect on alloxan-induced diabetic rats. In the present work we evaluated in vitro intestinal α-glucosidase inhibition as the possible mode of action of NSF extract on suppressing postprandial hyperglycemia for curing diabetic mellitus. In addition, NSF extract was studied to assess its possible acute oral toxicity and genotoxicity.

Materials and methods

Rat intestinal crude enzyme preparation and Caco-2 monolayer were used to evaluate α-glucosidase inhibitory activity of NSF extract. The main α-glucosidase inhibitors were detected by HPLC. For acute toxicity test, NSF extract was administered at doses of 2000, 5000 and 10,000 mg/kg body to three groups of 10 ICR mice each, and then clinical symptoms including mortality, clinical sign and gross findings were observed once a day for 14 days. In Ames test, histidine-dependent auxotrophic mutants of Salmonella typhimurium (strains TA97, TA98, TA100, TA102 and TA1535) were used and incubated in the presence and absence of S9 metabolic activation using NSF extract with concentrations of 150-5000 μg/plate. The chromosome aberration test was conducted with Chinese hamster lung (CHL) cells treated with NSF extract at doses of 150-5000 μg/ml in the presence and absence of S9 metabolic activation. In the in vivo mouse micronucleus assay, 9-week-old male and female ICR mice (n = 90, 25-30 g) were administered daily by oral gavage at doses of 2.5, 5.0 and 10.0 g/kg body for 1 or 2 days. Bone marrow smears were prepared from each treatment group 24 h after last administration and then polychromatic erythrocytes (PCEs) and normochromatic erythrocytes (NCEs) were identified.

Results

NSF extract showed potent rat intestinal α-glucosidase inhibitory activity for maltose hydrolysis with ED₅₀ value of 0.1 mg/ml. In Caco-2 monolayer, α-glucosidase activity for the maltose hydrolysis was down-regulated by NSF extract at a concentration of 0.05 mg/well level, showing 74% inhibition compared to the saline treated control. NSF was rich in phenol contents and the main α-glucosidase inhibitor, 1,2,3,4,6-penta-O-galloyl-β-d-glucose, was identified together with two phenolic compounds of gallic acid and corilagin. In acute toxicity test, NSF extract did not produce any toxic signs or deaths and the LD₅₀ value of this extract could be greater than 10,000 mg/kg body weight. These results of genotoxicity assessment showed that NSF extract did not cause genotoxic effects in Ames test, in the in vitro chromosomal aberration assay and in the in vivo micronucleus assay.

Conclusion

The current study shows that the extract from Nymphaea stellata flowers exhibits significant intestinal α-glucosidase inhibitory activity, without showing any acute toxicity or genotoxicity, which may be useful in suppressing postprandial hyperglycemia in diabetics. The results presented here suggest that the use of NSF in folk medicine as a natural antidiabetic treatment could be safe as well as beneficial.     

三种方法检测泌尿生殖道沙眼衣原体的比较

目的用三种方法检测泌尿生殖道沙眼衣原体,评价其方法的敏感性和特异性.方法采用C-C快速法、PCR和VIDAS CHL三种方法检测150例尿道或宫颈分泌物标本.结果在150例患者中,阳性患者43例,阳性率为28.67％,C-C快速法检测的敏感性与特异性为97.67％和100％,PCR检测的敏感性和特异性为100％和98.13％,VIDAS CHL检测的敏感性和特异性为97.67％和97.20％.结论三种方法检测泌尿生殖道沙眼衣原体的敏感性和特异性无显著性差异(P＞0.05).     

Superior semicircular canal dehiscence in a young child: implication of developmental defect

In recent years, superior semicircular canal dehiscence (SSCD) has been recognized as a structural cause of a number of auditory and vestibular symptoms, such as vertigo and conductive hearing loss. Prior clinical studies on SSCD have commonly described this entity in adults, but rarely in the pediatric population. We present a pediatric patient with right-sided SSCD which was initially diagnosed radiographically at age seven. This rare and unique case demonstrated SSCD can be found in young children, although the majority of patients with SSCD are adults. It also provides strong evidence that canal dehiscence may be a developmental defect.     

环氧司坦的诱变性研究

本文应用中国仓鼠肺细胞(CHL)和小鼠骨髓细胞的染色体畸变,研究了环氧司坦的诱变作用。离体CHL细胞培养分代谢活化和非代谢活化二个系列,环氧司坦剂量分别为0μg/ml、20μg/ml、40μg/ml和80μg/ml。小鼠在体试验剂量为0mg/kg、240mg/kg、480mg/kg和960mg/kg,均一次性灌胃给药,并设阳性对照组。结果表明,离体CHL细胞代谢活化与非代谢活化组和小鼠骨髓细胞各剂量组的染色体畸变率小于5%,而阳性对照分别为76%、51%和42%。各处理组与阴性对照组间经统计学分析,无显著性差异,提示了环氧司坦无细胞学诱变作用。     

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).