靶器官毒性剂量法在玉竹中铅、镉和砷联合暴露评估中的应用

目的:对于玉竹中铅(Pb)、镉(Cd)和砷(As)的残留量进行测定,探索靶器官毒性剂量法在评估中药中重金属联合暴露风险中的应用.方法:根据玉竹中Pb,Cd和As的残留量监测数据,计算其暴露量.采用危害指数(HI)法对Pb,Cd和As联合暴露产生的健康风险进行初步筛查.若危害指数(HI)值>1或其中2种或2种以上重金属的...     

ICP-MS法测定5种中药材粉剂中5种重金属的含量

目的:测定唐山市市售5种主要中药材粉剂三七、当归、川芎、首乌、大黄中铅(Pb)、镉(Cd)、汞(Hg)、砷(As)、铜(Cu)5种重金属的含量。方法:采用微波消解-电感耦合等离子体质谱法进行测定,并采用单因子指数法和内梅罗综合指数法对中药材粉剂样品中的重金属污染进行评价;采用《药用植物及制剂进出口绿色行业标准》的重金属限量值评价样品重金属污染状况。结果:在5种12个批次的中药材粉剂样品中,重金属超标样品2个,分别是三七-3、川芎-2,样品超标率为16.7%,超标重金属为Cd、Hg,超标率分别为16.7%、8.3%;单因子指数>1的样品有三七-3中的Cd和Hg,川芎-2中的Cd,综合指数分别为1.06、0.81,污染水平分别为轻污染和警戒线水平。结论:唐山市市售中药材粉剂中存在一定程度的重金属污染。因此,有必要对中药材中的重金属含量进行更加严格的控制。     

甘肃地产药材中重金属含量测定

目的：以甘肃地产20种药材为研究对象进行砷、铅、镉、铜4种重金属元素含量的测定。方法以石墨炉原子吸收分光光度法对铅、镉进行测定,火焰吸收法对铜进行测定,氢化物发生器法对砷进行测定。结果甘肃地产20种药材中四种重金属含量符合《药用植物及制剂进口绿色行业标准》要求,但有部分药材均不同程度地受到重金属的污染。结论应查明污染原因,有效控制药材中重金属含量。     

地龙中重金属及有害元素的含量分析与安全性评价

目的 对地龙中重金属及有害元素的含量进行测定、分析与安全性评价,研究中药重金属及有害元素与药材产地的相关性.方法 样品经过微波消解后,采用电感耦合等离子体质谱(ICP-MS)法测定其铅、镉、砷、汞、铜的残留量.利用单因子污染指数法和内梅罗综合污染指数法对其安全性进行评价.结果 9个产地17个批次地龙中铅、镉、砷、汞、铜...     

ICP-MS法测定中药白术重金属有害元素及风险评估

目的:采用电感耦合等离子体质谱(ICP-MS)法测定中药白术铜、铅、砷、镉、汞5种重金属的含量,并根据测定结果进行健康风险评估。方法:样品经微波消解后,以锗、铟、铋为内标,进行ICP-MS测定铜(Cu)、铅(Pb)、砷(As)、镉(Cd)、汞(Hg)5种元素,根据测定结果采用靶标危害系数法(THQ)进行健康风险评估。结果:Cu、Pb、As、Cd和Hg 5种待测元素的线性关系良好(r≥0.999 2),回收率为88.8%～108.4%;RSD的范围为2.2%～5.4%。风险评估结果显示白术中的重金属及有害元素所致安全性风险较低。结论:该方法为中药白术中的重金属及有害元素测定和风险评估提供了科学依据。     

17种中药材中重金属污染分析与健康风险评估

目的 对17种中药材中残留的5种重金属进行污染程度评价和健康风险评估，为中药材快速检验方法的开发提供理论依据和数据支持。方法 电感耦合等离子体质谱法测定17种中药材中的重金属残留量，采用超标率、单因子污染指数法、内梅罗污染综合指数法进行重金属污染程度评价，采用每日最大可耐受摄入量( estimated daily intake, EDI )、靶向危害系数( target hazard quotients, THQ )、累计目标危害系数( total target hazard quotient, TTHQ )进行健康风险评估。结果 17种中药材按总超标率大小排序为干姜>独活>柴胡>细辛>白附子>川芎>天麻>沉香>板蓝根>菊花>阳春砂>栀子>芡实>白芷>金银花>广藿香>苍术；Hg超标最普遍，涉及14种药材，以干姜中Hg超标最严重，导致干姜的单项和综合污染指数评价均为重度污染级，3种污染评价结果基本一致；有13种药材还存在多种重金属同时超标现象，如白附子存在Cd、Pb、Hg和As4种重金属超标；17种中药材的健康评估风险均无明显的健康风险危害。结论 17种药材均存在不同程度的重金属超标现象，污染现象普遍，形势严峻，虽然无明显健康危害，但重金属累积风险的加重，势必会影响中药材质量，进而危害人体健康，因此，要对中药材重金属污染问题加以重视，并采取有利的监测手段加以控制。     

乙肝扶正胶囊中重金属及有害元素的含量测定

目的 测定11批次市售乙肝扶正胶囊中的铅、镉、砷、汞4种重金属及有害元素含量,并进行风险评估.方法 样品经微波消解后,采用电感耦合等离子体质谱仪测定铅、镉、砷、汞元素含量,并采用ICH和JECFA评估数据计算各元素最大允许残留量.结果 11批次样品中,镉、汞均未超标,部分样品砷、铅元素含量较高,存在安全风险.结论 分析...     

林州太行山不同地块丹参药材中重金属含量比较研究

目的比较林州太行山不同地块、不同生产年限丹参药材中重金属铅、镉、砷、汞和铜的含量,对不同地块丹参药材重金属污染情况进行初步分析。方法采用原子吸收分光光度法测定林州太行山丹参药材中重金属含量,其中石墨炉法测定铅元素、镉元素含量,氢化物法测定砷元素含量,冷蒸气吸收法测定汞元素含量,火焰原子吸收法测定铜元素含量。结果林州太行山不同地块丹参药材中重金属铅、镉、砷、汞和铜的含量均低于标准规定值,符合规定。结论通过对林州太行山不同地块及不同生产年限丹参药材中重金属进行的含量测定,对丹参药材重金属污染情况进行了初步分析,为评价林州太行山丹参质量优劣提供了依据。     

原子吸收光谱法测定小活络丸中重金属的含量

目的:测定34家企业生产的小活络丸中铅、镉、砷、汞、铜的含量。方法:采用微波消解样品,石墨炉原子吸收分光光度法测定铅、镉、砷的含量;氢化物原子吸收分光光度法测定汞的含量;空气-乙炔火焰原子吸收分光光度法测定铜的含量。结果:34家企业生产的小活络丸中,铅、镉、砷、汞均有不同程度的超出规定限度。结论:该方法简单、准确,可用于小活络丸中重金属的含量测定。     

石墨炉原子吸收光谱法测定中成药中重金属的含量

目的:测定中成药银丹心脑通胶囊、金莲花胶囊和七叶安神滴丸中重金属铅、砷、镉的含量。方法:采用石墨炉原子吸收光谱法,样品消化后直接进行测定。结果:重金属铅、砷、镉的进样浓度分别在3～18、20～80、0.2～1.2μg.L-1范围内与吸光度线性关系良好,r分别为0.9996、0.9999、0.9998;3种成分的回收率在95%～103%之间。结论:上述中成药中所含铅、砷、镉含量均符合规定;本法简单、快速、灵敏,适用于中成药中微量重金属的分析。     

Interaction of estrone and estradiol with DNA and protein of liver and kidney in rat and hamster in vivo and in vitro

[6,7-³H] Estrone (E) and [6,7-³H]estradiol-17 (E₂) have been synthesized by reduction of 6-dehydroestrone and 6-dehydroestradiol with tritium gas. Tritiated E and E₂ were administered by oral gavage to female rats and to male and female hamsters on a dose level of about 300 g/kg (54 mCi/kg). After 8 h, the liver was excised from the rats; liver and kidneys were taken from the hamsters. DNA was purified either directly from an organ homogenate or via chromatin. The radioactivity in the DNA was expressed in the units of the Covalent Binding Index, CBI = (mol chemical bound per mol DNA-P)/(mmol chemical administered per kg b.w.). Rat liver DNA isolated via chromatin exhibited the very low values of 0.08 and 0.09 for E and E₂, respectively. The respective figures in hamster liver were 0.08 and 0.11 in females and 0.21 and 0.18 in the males. DNA isolated from the kidney revealed a detectable radioactivity only in the female, with values of 0.03 and 0.05 for E and E₂, respectively. The values for male hamster kidney were < 0.01 for both hormones. The minute radioactivity detectable in the DNA samples does not represent covalent binding to DNA, however, as indicated by two sets of control experiments. (A) Analysis by HPLC of the nucleosides prepared by enzyme digest of liver DNA isolated directly or via chromatin did not reveal any consistent peak which could have been attributed to a nucleoside-steroid adduct. (B) All DNA radioactivity could be due to protein contaminations, because the specific activity of chromatin protein was determined to be more than 3,000 times higher than of DNA. The high affinity of the hormone to protein was also demonstrated by in vitro incubations, where it could be shown that the specific activity of DNA and protein was essentially proportional to the concentration of radiolabelled hormone in the organ homogenate, regardless of whether the animal was treated or whether the hormone was added in vitro to the homogenate.Carcinogens acting by covalent DNA binding can be classified according to potency on the basis of the Covalent Binding Index. Values of 10³–10⁴ have been found for potent, 10² for moderate, and 1–10 for weak carcinogens. Since estrone is moderately carcinogenic for the kidney of the male hamster, a CBI of about 100 would be expected. The actually measured limit of detection of 0.01 places covalent DNA binding among the highly unlikely mechanisms of action. Similar considerations can be made for the liver where any true covalent DNA binding must be below a level of 0.01. It is concluded that an observable tumor induction by estrone or estradiol is unlikely to be due to DNA binding.Paper presented at the Satellite Symposium of the European Society of Toxicology, Rome, March 29, 1983     

Arsenic induced changes in growth development and apoptosis in neonatal and adult brain cells in vivo and in tissue culture

Arsenic at a nonlethal level in drinking water consumed over a period of time has been reported to produce chronic toxicity and various types of health problems ranging from skin cancer to disturbance in memory. Neurotoxic effects have been reported in clinical cases with chronic exposure to arsenic. Physiological detoxication of arsenic occurs partially through methylation. Arsenic and its methylated derivatives are distributed in different organs and systems. The present study examined the possible interference in the neuronal development and differentiation due to the exposure to arsenic during gestation. The experiments were carried out to examine short and long term effects of arsenic on brain explants and cells grown and maintained in tissue culture system. The effects of arsenic exposure showed changes in brain cell membrane function indicated by generation and release of reactive oxygen-nitrogen intermediates. On the morphological aspect the explants' growth was reduced, ground matrix was lost and neural networking was inhibited. Cells showed signs of apoptotic changes. Arsenic toxicity may induce damage to brain cells prior to more visible clinical conditions. The deleterious effects also pass from the maternal to fetal tissue across the transplacental barrier.     

Nicotine metabolism and urinary elimination in mouse: in vitro and in vivo

This study aimed at elucidating the in vivo metabolism of nicotine both with and without inhibitors of nicotine metabolism. Second, the role of mouse CYP2A5 in nicotine oxidation in vitro was studied as such information is needed to assess whether the mouse is a suitable model for studying chemical inhibitors of the human CYP2A6. The oxidation of nicotine to cotinine was measured and the ability of various inhibitors to modify this reaction was determined. Nicotine and various inhibitors were co-administered to CD2F1 mice, and nicotine and urinary levels of nicotine and four metabolites were determined. In mouse liver microsomes anti-CYP2A5 antibody and known chemical inhibitors of the CYP2A5 enzyme blocked cotinine formation by 85–100%, depending on the pre-treatment of the mice. The amount of trans-3-hydroxycotine was five times higher than cotinine N-oxide, and ten times higher than nicotine N-1-oxide and cotinine. Methoxsalen, an irreversible inhibitor of CYP2A5, significantly reduced the metabolic elimination of nicotine in vivo, but the reversible inhibitors had no effect. It is concluded that the metabolism of nicotine in mouse is very similar to that in man and, therefore, that the mouse is a suitable model for testing novel chemical inhibitors of human CYP2A6.     

Circulating nucleic acids in plasma and serum: roles in diagnosis and prognosis in diabetes and cancer

The presence of DNA and RNA circulating in human plasma and serum is described. The possible sources of the DNA/RNA in blood, their ability to enter other cells and to express in the recipient cells are discussed and the relationship with metastases considered. The possible role(s) of the DNA/RNA in clinical diagnosis, in monitoring treatment and in prognosis are considered for diabetes and oncology.     

SalB stimulates neurogenesis and angiogenesis in vitro and in vivo

Aims： Previous studies suggested that Salvianolic acid B （SalB） has strong protective effect against cerebral ischemia. Recently, Sal B has been reported to enhance angiogenesis in vitro. Based on the information above, in this study we are interested in the effect of SalB on neurogenesis and angiogenesis. Methods：In vitro study, we used embryonic mouse （El6） primary cortical neural cultures. Neuron was recognized by anti-MAP2 with immunocytochemistry. Neurogenesis was tested with BrdU incorporation by ELSA method. SalB（ 10 -6 -10 -8M） or vehicle was added to the culture medium 24 hrs before BrdU addition. In vivo, middle cerebral artery occlusion （MCAO） rats were used as focal cerebral ischemia model.     

Pharmacokinetic and pharmacogenetic determinants and considerations in chemotherapy selection and dosing in infants

INTRODUCTION: There is a lack of high-quality data regarding optimal chemotherapy dosage regimens among infants. Dosing regimens for chemotherapy during the first year of life are commonly based on empiric recommendations extrapolated from older children; however, balancing efficacy and toxicity is critical as severe adverse drug reactions may lead to treatment failure or reduced adherence to needed medications. AREAS COVERED: This review describes pharmacokinetic and pharmacogenetic considerations when administering chemotherapeutic agents to infants. Examples of commonly used agents are provided with practical recommendations for dosing adjustments. EXPERT OPINION: Optimal chemotherapy for children and infants in particular has lagged behind the remarkable progress in cancer treatment and it is clear that far more basic and clinical research are needed with respect to the mechanistic basis of age-dependent differences in pharmacokinetic parameters. More recent studies which have combined pharmacokinetic data with clinical toxicity and outcome data have resulted in a number of more evidence-based guidelines at least for the initial chemotherapy dosing; however, at present, the dosing of chemotherapy drugs in neonates and infants remains largely empiric.     

Consistency in catecholamine and cortisol excretion in males and females

Data from a series of experiments performed on 24 female and 24 male subjects were used to evaluate the consistency in urinary catecholamine and cortisol excretion. Data were available from 8 laboratory situations of varying activity level and content, spaced at intervals of maximum 3 months. Correlational analyses showed that for cortisol, interindividual consistency was higher for measures obtained on the same day than for measures obtained on different days. Interindividual consistency was generally high in catecholamine and cortisol excretion during non-stressful situations in both sexes. During experimental stress, however, consistency was as high as during nonstress for males, while it was lower for females. Analysis of variance components confirmed these results and showed that in males variation due to interindividual differences was high during both baseline and experimental-stress situations, while in females it was high during baseline situations only. During experimental stress, variation for females was due primarily to interaction. It is suggested that the males showed a more generalized stress response over situations than the females.     

Metabolic interaction between imipramine and carbamazepine in vivo and in vitro in rats

Summary The pharmacokinetic consequences of the combination of carbamazepine with imipramine in male Wistar rats have been investigated. It was found that a 2-week treatment with the combination resulted in the increase of the concentrations of the parent compounds and a simultaneous decrease in their metabolites in blood plasma i.e. carbamazepine inhibited imipramine demethylation in the side chain while imipramine inhibited carbamazepine 10,11-epoxidation. The velocity of imipramine 2-hydroxylation and 10,11-epoxy-carbamazepine hydration did not seem to be changed by the combination. On the basis of studies in vitro it is concluded that the observed metabolic interaction between carbamazepine and imipramine is due to the competition of the drugs for the active centre of cytochrome P 450 and to a certain qualitative alteration of the enzyme by imipramine as can be deducted from the decrease of carbamazepine binding to the cytochrome. Send offprint requests to K. J. Netter