Modeling developmental data using U-shaped threshold dose-response curves

The performance of Cobas HPV test for cervical cancer screening in Chinese female migrant workers

This study aimed to evaluate the performance of Cobas human papillomavirus (HPV) test in cervical cancer screening. A total of 3442 women aged ⩾20 years used Cobas HPV and hybrid capture 2 (HC2) tests were included in this study. Women with any positive result were examined by liquid-based cytology (LBC) test. Then subjects with abnormal LBC or positive Cobas HPV16/18 were further checked by colposcopy to observe the visible lesions to perform the pathological examination. Of these 3442 women, 328 cases were Cobas HPV positive, and the positive rate was 9.53% (95% confidence interval (CI) 8.50–10.53). The positive rate of HPV16, HPV18, and other 12 types of high-risk HPV were 1.54% (95% CI 1.12–1.95), 0.55% (95% CI 0.30–0.80), and 7.44% (95% CI 6.56–8.32), respectively. The coincidence rate of Cobas HPV test and HC2 test was 90% (95% CI 89.00–91.00; Kappa = 0.526) in the primary screening. Age had a non-linear relationship with Cobas HPV positive rate (χ² = 4.240, P = 0.040) and HPV16/18 typing positive rate (χ² = 6.610, P = 0.010). Compared with the LBC test, the Cobas HPV test had higher sensitivity when detecting patients with high cervical intraepithelial neoplasia (CIN2+ and CIN3+).

Bisphenol S exposure alters behavioral parameters in adult zebrafish and offspring

The environmental emission of bisphenol S (BPS), which is globally utilized in the manufacturing of polycarbonates, epoxy resin and thermal paper, has affected the aquatic ecosystem. Thus, effects of BPS exposure on the fitness of aquatic animals have been noted. Here, adult male and female zebrafish were used as aquatic model organisms and separately exposed to environmentally relevant doses of BPS (0, 1, 10 and 100 μg/L) for 14 days. The results showed that BPS changed the body pigment of zebrafish and slowed the maturation of oocytes in the ovary, resulting in a significant decrease in the shoaling behavior of adult zebrafish and the attraction of BPS-treated females during the mating process. Furthermore, in the subgeneration of adult zebrafish exposed to BPS for 7 days, survival behaviors, such as locomotor, phototaxis and feeding behaviors, deviated from normal behaviors. After exposing the adult zebrafish to BPS for an additional 7 days, the above described survival behaviors and light adaptation were disrupted in offspring. Our data, based on intergenerational behavioral studies, demonstrate that BPS affects the behaviors of aquatic animals and the ability of offspring to feed and avoid predators, possibly jeopardizing the survival of aquatic animals.

Statistical power considerations show the endocrine disruptor low-dose issue in a new light

BACKGROUND

The endocrine disruptor field has been vexed by difficulties in reproducing various claims of effects at unusually low doses. In previous analyses, variations in control responses from experiment to experiment and problems with observing effects in positive controls have been identified as possible explanations of the resulting impasse.

OBJECTIVE

In this article, we argue that both of these viewpoints fail to take sufficient account of the problems that exist in estimating low effects and low-effect doses. We have carried out post hoc power analyses on selected published data to illustrate that claims of low-dose effects (or their absence) are often compromised by insufficient statistical power of the chosen experimental design.

CONCLUSIONS

We demonstrate that low-dose estimates such as the no observed adverse effect levels derived from statistical hypothesis-testing procedures are dependent on the specific experimental conditions used for testing. Thus, below the statistical detection limit of the experiment, the presence of effects can neither be proven nor ruled out. Common practice is to attempt to establish "doses without effect." However, low-dose estimations in the endocrine-disruptor field could be improved if decisions regarding the toxicologic effect size of relevance formed the starting point of testing procedures. Statistical power considerations could then reveal the resources necessary to demonstrate effect magnitudes of concern.