A case of drug-induced hematotoxicity: from in vivo to in vitro assessment

As part of the early preclinical development of a new antipsychotic compound, Wistar rats of both sexes were dosed orally for upto 7 days. At high doses, expected changes in appearance and behavior, decreases in bodyweight gain and feed intake but also a fluid and pale bone marrow (BM) were observed. Blood cell counts were normal as were clinical chemical values. BM sections showed a red cell hypoplasia. Circulating reticulocytes and erythroblasts on BM smears were decreased suggesting that the compound might have a selective toxicity for the erythroid lineage. In a mechanistic experiment, rats were dosed for 9 days and phlebotomized after 7 days of exposure to stimulate erythroid regeneration. Red-blood cell mass, reticulocytes and erythropoietin (EPO) levels were monitored before and upto 48 h after bleeding. Results showed that an EPO-mediated pathogenesis could be excluded. The effect of the drug on the formation of Colony-forming units (CFU)-E and CFU-GM was then quantitatively measured in vitro after direct exposure to the compound. In two successive assays, rat or human BM cells were incubated with the drug dissolved in the collection medium at final concentrations of 0.3×10^–7 –3×10^–5 M. In the presence of adequate growth factors, CFU-E and CFU-GM were cultured and cell proliferation was compared between treated and control groups. Our results showed an expected inhibition by the drug of the growth of erythroid progenitors associated to a similar effect on myeloid progenitors. The CFU-E and CFU-GM of both human and rat sources were totally inhibited from the concentration of 3×10^–5 M. The IC₅₀ values were consistent with rat peak plasma levels reached in vivo by the drug. Therefore, the short-term cloning assays performed on rat BM cells were sensitive indicators of the hematotoxicity of the compound and were considered as predictive for human toxicity.     

动物喂养辐照食品的安全性评价

本试验是在多种食品的基础上,加大照射剂量(吸收剂量为0.1～8.0 kGy)和提高辐照食品在膳食中比例(千重80％以上)的条件下,进行了150d的大白鼠喂养试验。通过对饲料的营养成分分析及其利用,对动物的生长发育、血液学、致突变性及病理学等项指标的检测,结果证明是安全的。本试验结果为今后辐照食品商业化提供了安全的证据。     

MNNG诱导大鼠胃癌模型的建立

目的 通过构建动物模型，为进一步研究胃癌转移及其生长过程中的一系列生物学表现提供实验材料。方法 根据饲养的不同阶段在饮水和饲料中添加MNNG喂养Wistar雄性大鼠，定期取材，HE染色，观察鉴定。结果 MNNG喂饲24周可见胃黏膜内癌；40周可见黏膜下层及肌层浸润癌。结论 阶段口服MNNG混合法可成功诱发Wistar大鼠胃腺癌。     

JX-1对雄性小鼠生殖细胞致突变作用的研究

本文采用小鼠精子试验和小鼠睾丸DNA合成抑制试验,检测了JX-1对雄性生殖细胞的致突变作用。实验结果表明JX-1对小鼠精子总数、精子活动率及精子畸形率均无统计学意义的增加,与小鼠睾丸DNA合成抑制试验阴性反应一致。作者认为JX-1对雄性生殖细胞为一种非诱变剂。     

3H-胸苷酸掺入法对选择前列腺癌化疗方案的价值

目的为临床选择激素难治性前列腺癌(HRPC)的化疗方案提供参考.方法采用3H-胸苷酸(3H-TdR)掺入法检测了20例HRPC细胞对常用化疗药物的敏感性.结果HRPC对单药的体外敏感性依次为足叶乙苷(VP16)＞阿霉素(ADM)、5-氟尿嘧啶(5-FU)、雌二醇氮芥(EMP)＞长春花碱(VLB)＞顺铂(DDP);二药联合可使敏感性进一步提高,依次为EMP加VP1 6、5-FU加ADM＞EMP加VLB＞5-FU加DDP三药联用抑瘤作用更强,EMP加VLB加APM、5 FU加ADM加DDP＞EMP加VLB加DDP.结论3H-TdR掺入法有助于化疗方案的选择,对HRPC以联合化疗效果较好.     

Relationship of clonogenic capacity to plating efficiency and vital dye staining of human periodontal ligament cells: implications for tooth replantation

The survival rate of avulsed permanent teeth following replantation is affected primarily by the duration of the extra-alveolar period and the nature of the storage conditions. These factors are believed to strongly affect the viability of periodontal ligament (PL) cells but in vitro assays of cell viability based on vital dye assays are only weakly correlated with the tooth survival rate after replantation. The aim of the present study was to examine the relative dependence of cell membrane integrity, attachment and clonogenic capacity of human PL cells on the temperature and duration of the extra-alveolar period and the type of storage medium. Twenty-four premolar teeth were extracted for orthodontic reasons from 9 patients 11–18 years of age. Teeth were maintained at 4°C or 23°C for 15, 30, 60 or 120 min in either milk or dry conditions. Cell membrane integrity was determined by BCECF/AM dye inclusion. Plating efficiency was determined by measurement of cell attachment at 3 and 6 h. The clonogenic capacity of progenitor cells was estimated by limiting dilution and colony counts. For all assays teeth stored in milk at 4°C showed the highest percentages of BCECF positive, attached cells with clonogenic capacity. Increased storage time (15–120 min) was associated with a 50% relative reduction of BCECF staining and a 5-fold relative reduction of cell attachment regardless of storage conditions. However, the clonogenic capacity of progenitor cells decreased 25-fold over the same duration of storage. These data demonstrate that in vitro assays of clonogenic capacity are much more sensitive to extra-oral storage time and storage conditions than dye inclusion or cell attachment. We suggest that in comparison with in vitro measures of cell membrane integrity, the clonogenic capacity of PL cells is more closely linked to tooth survival rate, probably reflecting the capacity of PL progenitor cells to recolonize the root surface after replantation.     

Profile of in Vitro Binding Affinities of Neuroleptics at Different Rat Brain Receptors: Cluster Analysis Comparison with Pharmacological and Clinical Profiles

A series of 21 neuroleptics with different chemical structures (phenothiazines, thioxanthenes, dibenzodiazepines, butyrophenones, benzamides, etc.) was examined for their in vitro interactions with 12 neurotransmitter binding sites in the rat brain (alpha- and beta-noradrenergic, dopaminergic, muscarinic, serotoninergic, histaminic, and opioid receptors, calcium channels, and serotonin uptake binding sites). The biochemical profile obtained from the binding data was compared with reported pharmacological and clinical profiles for this class of compounds by cluster analysis. Cluster analysis on binding data classified the compounds in three main subgroups: benzamides, compounds with an affinity mainly for DA2 and 5-HT2 receptors and inactive at muscarinic receptors, and compounds with a high affinity for alpha 1-adrenergic receptors and muscarinic receptors. The main subgroups resulting from cluster analysis of previously published pharmacological and clinical data for neuroleptics contain compounds common to the present study, with some correlations. The results extend previous observations that a complete binding profile corresponds to the pharmacological and clinical profile of this class of compounds.     

Comparison of the COBAS TaqMan HBV test with the COBAS Amplicor monitor test for measurement of hepatitis B virus DNA in serum

Quantitation of low hepatitis B virus (HBV) DNA levels in patients with chronic hepatitis B is important for monitoring natural history of disease and treatment efficacy. This study aimed to compare the quantitation range and analytical sensitivity of the newly developed COBAS TaqMan HBV test (TaqMan test) with the COBAS Amplicor HBV Monitor Test (Amplicor test), using the Eurohep HBV reference plasma and serum samples from patients. Serial dilutions (2.7x10(1)-2.7x10(8) copies/ml) of the Eurohep HBV reference plasma and 50 serum samples from chronic hepatitis B patients were tested by both assays. The TaqMan test could detect seven (2.7x10(2)-2.7x10(8) copies/ml) of eight dilutions of the reference plasma, while the Amplicor test could only detect three of them (2.7x10(3)-2.7x10(5) copies/ml). The HBV DNA values measured by the TaqMan test correlated very well with the theoretical Eurohep standard values (r=0.998, P<0.001). There were good correlations between the HBV DNA levels measured by the two assays on both the Eurohep reference plasma (r=0.993, P<0.001) and serum samples from patients (r=0.904, P<0.001). Compared to the Amplicor test, the TaqMan test had a higher sensitivity (50 vs. 300 copies/ml), shorter assay time (6 vs. 10 hr), and wider dynamic range (8 vs. 3 logs), and was more cost-effective in a clinical setting. These data indicate that the TaqMan test is an excellent tool for HBV DNA quantitation.     

Rapid diagnosis of parasitic diseases: current scenario and future needs

Background

Parasitic diseases are one of the world's most devastating and prevalent infections, causing millions of morbidities and mortalities annually. In the past, many of these infections have been linked predominantly to tropical or subtropical areas. Nowadays, however, climatic and vector ecology changes, a significant increase in international travel, armed conflicts, and migration of humans and animals have influenced the transmission of some parasitic diseases from ‘book pages’ to reality in developed countries. It has also been noted that many patients who have never travelled to endemic areas suffer from blood-borne infections caused by protozoa. In the light of existing knowledge, this new trend can be explained by the fact that in the process of migration a large number of asymptomatic carriers become a part of the blood bank donor and transplant donor populations. Accurate and rapid diagnosis represents the crucial weapon in the fight against parasitic infections.