Evaluation of estrogenic activities of pesticides using an in vitro reporter gene assay

The estrogenic activities of 32 pesticides in agricultural products were evaluated using the E-CALUX assay system developed by Xenobiotic Detection Systems Inc (North Carolina, USA). This system utilizes human ovarian carcinoma cells (BG1) stably transfected with an estrogen-responsive luciferase reporter gene plasmid. It was found that tolclofos-methyl, prothiofos, diazinon, Thiabenclazole (TBZ) and pyriproxyfen had estrogenic activity. Several pesticides are often present in agricultural products. Therefore the estrogenicity of the mixtures of two kinds of pesticides was evaluated. The activity of diazinon/tolclofos-methyl, pyriproxyfen/prothiofos and TBZ/o-phenylphenol (OPP) was increased up to 1.2-5.3 fold. On the other hand, chlorfluazuron, imazalil and chlorfenapyr had anti-estrogenic activity. Further, to evaluate the change in the estrogenic activity of pesticide metabolites, an experimental system was established using a rat S9 mixture. Metabolites of permethrin and OPP had no estrogenic activity, but they had weak activity after the metabolism. On the other hand, the metabolites of TBZ exhibited less estrogenic activity than the original compounds.     

On the efficiency of targeted clinical trials

The development of genomics-based technologies is demonstrating that many common diseases are heterogeneous collections of molecularly distinct entities. Molecularly targeted therapeutics is often effective only for some subsets patients with a conventionally defined disease. We consider the problem of design of phase III randomized clinical trials for the evaluation of a molecularly targeted treatment when there is an assay predictive of which patients will be more responsive to the experimental treatment than to the control regimen. We compare the conventional randomized clinical trial design to a design based on randomizing only patients predicted to preferentially benefit from the new treatment. Trial designs are compared based on the required number of randomized patients and the expected number of patients screened for randomization eligibility. Relative efficiency depends upon the distribution of treatment effect across patient subsets, prevalence of the subset of patients who respond preferentially to the experimental treatment, and assay performance.     

Influence diagnostics for two-component Poisson mixture regression models: applications in public health

In many medical and health applications, Poisson mixture regression models are commonly used to analyse heterogeneous count data. Motivated by two data sets drawn from public health studies, influence diagnostics are proposed for assessing the sensitivity of the fitted two-component Poisson mixture regression models. Under various perturbations of the observed data or model assumptions, influence assessments based on the local influence approach are developed for detecting clusters and/or individual observations that impact on the estimation of model parameters. Results from studies on recurrent urinary tract infections and maternity length of stay illustrate the usefulness of the influence diagnostics.     

Comparative in vitro and in vivo genotoxicities of 7H-benzo[c]fluorene, manufactured gas plant residue (MGP), and MGP fractions

Manufactured gas plant residue (MGP) is a complex mixture of polycyclic aromatic hydrocarbons (PAHs) that is tumorigenic in the lungs of mice. This study compared the relative genotoxicity of 7H-benzo[c]fluorene (BC), a PAH component of MGP, with MGP and MGP fractions in order to assess the contribution of BC to the genotoxicity of MGP. An MGP sample was separated into seven fractions (F1-F7) using silica gel column chromatography with petroleum ether (PE) followed by PE:acetone (99:1 v/v, then 98:2). PAHs were quantified using gas chromatography/mass spectrometry. An aliquot of F2, the fraction with the highest BC concentration and highest weighted mutagenic activity in Salmonella typhimurium strain TA98, was further separated using silica gel thin-layer chromatography with hexane. The first F2 subfraction, sF2-a, was enriched in BC and coeluting compounds and contained 35,000 ppm BC and 216,109 ppm carcinogenic PAHs (cPAHs, the sum of seven PAHs categorized by the U.S. EPA as class B2 carcinogens). The second F2 subfraction, sF2-b, contained a ninefold lower concentration of BC, with 3,900 ppm BC and 45,216 ppm cPAHs. Female ICR mice received topical application of crude MGP, crude MGP spiked with analytical-grade BC, F2, sF2-a, sF2-b, or analytical-grade BC. DNA adduct levels were analyzed by nuclease P1-enhanced (32)P-postlabeling. In lung DNA of mice receiving 0.48 or 3.0 mg/mouse, net total RAL x 10(9) values were F2, 30.8 and 87.2; sF2-a, 24.8 and 106.7; and sF2-b, 19.6 and 151.0, respectively. Mice dosed with 0.10 mg analytical-grade BC (the mass of BC in 3.0 mg sF2-a) exhibited a net total RAL x 10(9) value of 7.03 in lung DNA. This was equal to approximately 7% of the total RAL x 10(9) value produced by 3.0 mg sF2-a. Thus, although BC appears to make an appreciable contribution to pulmonary adduct formation, the results suggest that MGP components other than BC play an important role in lung DNA adduct formation following topical MGP administration.     

Effects of a phasic oral contraceptive containing desogestrel on facial seborrhea and acne

BACKGROUND: The combined oral contraceptive containing ethinylestradiol and the selective progestogen, desogestrel, in a phasic regimen (DSG-OC, Tri-merci) has been shown to reduce facial oiliness. OBJECTIVE: This study was designed to evaluate further the effects of this OC on the skin of women with facial seborrhea and mild or moderate acne. DESIGN AND METHODS: This was an open, noncomparative, bicenter study in 60 healthy Russian women, aged 18-30 years, with facial seborrhea and mild or moderate facial acne, who wished to use oral contraception. All women received the OC containing desogestrel (50/100/150 microg) and ethinylestradiol (35/30/30 microg) for three phases of 7 days followed by a 7-day pill-free interval, for six cycles. Seborrhea was assessed using the Sebutape technique, in which strips of adhesive microporous polymeric film pressed onto facial sites are used to assess sebaceous activity. Acne was assessed by counting facial lesions. Subjective evaluations of skin and hair condition, patients' feelings to them and satisfaction with the OC were made using a visual analogue scale (VAS). Assessments were made at baseline, and after one, three and six treatment cycles. RESULTS: Sebutape assessments of seborrhea were significantly improved, on the right and left cheeks, after one treatment cycle, and on the forehead after three treatment cycles. These improvements increased steadily and were much larger at the end of Cycle 6. Acne grades were significantly improved after three and six treatment cycles. VAS scores in response to questions dealing with self-esteem and self-confidence were significantly improved after three cycles and in some cases after just one cycle. The women's views of their skin and hair (greasiness) were correspondingly significantly improved. Subjective assessments indicated that after one, three and six cycles, 69%, 93% and 98%, respectively, of women were satisfied or very satisfied with the DSG-OC. CONCLUSION: In women with facial seborrhea and mild or moderate acne, the use of DSG-OC appears to improve seborrhea after just one cycle and acne grades after three cycles. These improvements are accompanied by increases in self-esteem and confidence.     

ROC analysis for markers with mass at zero

The receiver operating characteristic (ROC) curve and in particular the area under the curve (AUC) is commonly used to examine the discriminatory ability of diagnostic markers. Certain markers while basically continuous and non-negative have a positive probability mass (spike) at the value zero. We discuss a flexible modelling approach to such data and contrast it with the standard non-parametric approach. We show how the modelling approach can be extended to take account of the effect of explanatory variables. We motivate this problem and illustrate the modelling approach using data on the coronary calcium score, measured by electron beam tomography, which is a marker for atherosclerosis.     

Bayesian sample size calculations in phase II clinical trials using a mixture of informative priors

A number of researchers have discussed phase II clinical trials from a Bayesian perspective. A recent article by Mayo and Gajewski focuses on sample size calculations, which they determine by specifying an informative prior distribution and then calculating a posterior probability that the true response will exceed a prespecified target. In this article, we extend these sample size calculations to include a mixture of informative prior distributions. The mixture comes from several sources of information. For example consider information from two (or more) clinicians. The first clinician is pessimistic about the drug and the second clinician is optimistic. We tabulate the results for sample size design using the fact that the simple mixture of Betas is a conjugate family for the Beta- Binomial model. We discuss the theoretical framework for these types of Bayesian designs and show that the Bayesian designs in this paper approximate this theoretical framework.     

Modulation of human renal cell carcinoma 786-0 MMP-2 and MMP-9 activity by inhibitors and inducers in vitro

A hallmark of renal cell carcinoma (RCC) invasion is its ability to degrade ECM by local production of gelatinase enzymes. Although many studies on RCC have demonstrated the importance of MMPs, very little information is currently known regarding the effect of inducers and inhibitors. We therefore investigated the effect of inducers and inhibitors on RCC 786-0 in vitro. Human RCC 786-0 (ATCC) was grown in RPMI medium supplemented with 10% FBS, penicillin, and streptomycin in 24-well tissue plates. At near confuence, the cells were washed with PBS; the serum-free medium was incubated with various inducers: phorbol ester (PMA), tumor necrosis factor alpha (TNF-α), interleukin 1-beta (IL-β) and lipopolysaccharides (LPS). Cells were also incubated with inhibitors: EGCG, doxycycline, and a nutrient mixture with and without PMA; retinoic acid, dexamethasone, H-7; actinomcin D, or cyclohexamide. After 24 h, the medium was removed and analyzed for MMP-2 and MMP-9 by gelatinase zymography. RCC 786-0 secreted two bands, a major band corresponding to MMP-2 and a faint band corresponding to MMP-9. PMA and TNF-α, with increased concentration, increased MMP-9 secretion, while IL-1β and LPS did not significantly modify MMP-9 activity. MMP-2 secretion was not affected by any of the inducers. All the inhibitors tested without and with PMA showed a dose-dependent decrease in both MMP-2 and-9 expression. Further studies are in progress to confirm the role of MMP-9 on Matrigel invasion using PMA, cytokines, and LPS.     

咽喉炎合剂中黄芩苷的稳定性考察

目的:考察咽喉炎合剂的稳定性。方法:采用经典恒温加速试验法和留样观察法,以黄芩苷的含量作为考察指标,采用高效液相色谱(HPLC)法测定其含量的变化。结果:咽喉炎合剂中黄芩苷的含量变化符合一级动力学过程,2种考察方法的结果基本一致。在室温(25℃)条件下,咽喉炎合剂的有效期为1.06a。结论:建议咽喉炎合剂质量标准中有效期订为室温保存1a。     

解郁化痰合剂联合氯米帕明治疗抑郁障碍的临床研究

目的 通过对西药、中药、中西药合用治疗抑郁障碍的临床疗效观察,寻找抗抑郁障碍安全、有效、顺从性好的治疗方案.方法 将120例符合抑郁障碍诊断标准和<中医内科学>抑郁病诊断标准的患者随机分为3组,A组:口服氯米帕明25mg,3/d;解郁化痰合剂50ml,2次,d;B组:口服解郁化痰合剂50ml,2次/d;C组:口服氯米帕明25 mg,3次/d.观察时间为6周,评估各组的疗效和安全性.结果 完成治疗116例,临床总显效率、症候显效率、汉密尔顿抑郁量表(HAMD)总减分率,A组分别为95.00%、92.50%、69.13±29.47%,B组分别为69.23%、64.10%、53.22±25.78%,C组分别为70.27%、64.87%、53.47±26.29%.A组优于其他两组(P均＜0.01);B、C组间无明显差异(P＞0.05).抗抑郁药副反应量表评分A、B组低于C组(P均＜0.01):A、B组间无显著性差异(P＞0.05).结论 解郁化痰合剂联合氯米帕明治疗抑郁障碍疗效肯定、起效快、副作用少、患者易接受,是治疗抑郁障碍的有效方法之一.