The synthetic surfactant, perfluorooctanoic acid (PFOA) is a proven developmental toxicant in mice, causing pregnancy loss, increased neonatal mortality, delayed eye opening, and abnormal mammary ...gland growth in animals exposed during fetal life. PFOA is found in the sera and tissues of wildlife and humans throughout the world, but is especially high in the sera of children compared to adults. These studies in CD-1 mice aim to determine the latent health effects of PFOA following: (1) an
in utero exposure, (2) an
in utero exposure followed by ovariectomy (ovx), or (3) exposure as an adult. Mice were exposed to 0, 0.01, 0.1, 0.3, 1, 3, or 5
mg
PFOA/kg BW for 17 days of pregnancy or as young adults. Body weight was reduced in the highest doses on postnatal day (PND) 1 and at weaning. However, the lowest exposures (0.01–0.3
mg/kg) significantly increased body weight, and serum insulin and leptin (0.01–0.1
mg/kg) in mid-life after developmental exposure. PFOA exposure combined with ovx caused no additional increase in mid-life body weight. At 18 months of age, the effects of
in utero PFOA exposure on body weight were no longer detected. White adipose tissue and spleen weights were decreased at high doses of PFOA in intact developmentally exposed mice, and spleen weight was reduced in PFOA-exposed ovx mice. Brown adipose tissue weight was significantly increased in both ovx and intact mice at high PFOA doses. Liver weight was unaffected in late life by these exposure paradigms. Finally, there was no effect of adult exposure to PFOA on body weight. These studies demonstrate an important window of exposure for low-dose effects of PFOA on body weight gain, as well as leptin and insulin concentrations in mid-life, at a lowest observed effect level of 0.01
mg
PFOA/kg BW. The mode of action of these effects and its relevance to human health remain to be explored.
An increasing number of studies are utilizing the rodent mammary gland as an endpoint for assessing the developmental toxicity of a chemical exposure. The effects these exposures have on mammary ...gland development are typically evaluated using either basic dimensional measurements or by scoring morphological characteristics. However, the broad range of methods for interpreting developmental changes could lead to inconsistent translations across laboratories. A common method of assessment is needed so that proper interpretations can be formed from data being compared across studies. The present study describes the application of the Sholl analysis method to quantify mammary gland branching characteristics. The Sholl method was originally developed for use in quantifying neuronal dendritic patterns. By using ImageJ, an open-source image analysis software package, and a plugin developed for this analysis, the mammary gland branching density and the complexity of a mammary gland from a peripubertal female rat were determined. The methods described here will enable the use of the Sholl analysis as an effective tool for quantifying an important characteristic of mammary gland development.
•A reduced model for unconfined groundwater flow is proposed using POD and DEIM.•The algorithm implements the model within the framework of MODFLOW.•Two to three orders of reduction are achieved with ...the test cases.•The POD-DEIM reduced model run faster than the full model and the POD model.
Nonlinear groundwater flow models have the propensity to be overly complex leading to burdensome computational demands. Reduced modeling techniques are used to develop an approximation of the original model that has smaller dimensionality and faster run times. The reduced model proposed is a combination of proper orthogonal decomposition (POD) and the discrete empirical interpolation method (DEIM). Solutions of the full model (snapshots) are collected to represent the physical dynamics of the system and Galerkin projection allows the formulation of a reduced model that lies in a subspace of the full model. Interpolation points are added through DEIM to eliminate the reduced model's dependence on the dimension of the full model. POD is shown to effectively reduce the dimension of the full model and DEIM is shown to speed up the solution by further reducing the dimension of the nonlinear calculations. To show the concept can work for unconfined groundwater flow model, with added nonlinear forcings, one-dimensional and two-dimensional test cases are constructed in MODFLOW-OWHM. POD and DEIM are added to MODFLOW as a modular package. Comparing the POD and the POD-DEIM reduced models, the experimental results indicate similar reduction in dimension size with additional computation speed up for the added interpolation. The hyper-reduction method presented is effective for models that have fine discretization in space and/or time as well as nonlinearities with respect to the state variable. The dual reduction approach ensures that, once constructed, the reduced model can be solved in an equation system that depends only on reduced dimensions.
This study was performed to investigate changes in dentofacial characteristics associated with mouth breathing (MB) and adenoidectomy.
MB is considered to be an etiological factor of malocclusion. ...Adenoidectomy is supposed to have the ability to prevent the development of dentofacial deformities.
This retrospective study included 123 patients, namely 57 nose breathers, 19 former mouth breathers, who have undergone adenoidectomy, and 47 mouth breathers. The groups were compared according to their skeletal and dental characteristics. The measurements of each individual were obtained from lateral cephalograms and dental casts. The comparison was done using one-way ANOVA, Bonferroni post-hoc, Mann-Whitney U and Kruskal-Wallis tests. The statistically significant difference was defined as p<0.05.
The MB group showed an increase in ArGoMe (p=0.02) angle. No difference was found in the sagittal parameters among the groups. Upper dental arch compression was positively correlated with MB(p=0.00), even in adenoidectomy cases (p=0.01).
MB alters the vertical and transverse growth of the craniofacial complex. It is associated with longer lower anterior facial height and decreased maxillary intermolar distance. However, it does not influence the sagittal parameters. Airway clearance via adenoidectomy promotes the normalization of vertical parameters (Tab. 1, Fig. 2, Ref. 20).
Background: Atrazine (ATR), a widely used chlorotriazine herbicide, inhibits a number of endocrine-dependent processes, including gonadotrophin surges and mammary gland development in rats. ...Chlorotriazine herbicides are rapidly metabolized in plants and animals to form a group of metabolites that are detected both in the environment and in exposed animals. The extent to which these metabolites are responsible directly for the observed health effects is not understood. Objectives: Our goal was to determine if a mixture of ATR metabolites, in proportions found in the environment, might produce developmental effects in Long-Evans rats following exposure late in pregnancy. Methods: We administered an ATR metabolite mixture (AMM) containing ATR, hydroxyatrazine, diaminochlorotriazine, deethylatrazine, and deisopropylatrazine orally to pregnant Long-Evans rats at 0.09, 0.87, or 8.73 mg/kg body weight (bw)/day, on gestation days 15-19, using 0 and 100 mg ATR/kg bw/day as negative and positive controls, respectively. Results: We observed no significant effect of acute AMM exposure on body weight gain in dams during the dosing period, weight loss in pups on postnatal day (PND)4, or pubertal timing, as is seen with ATR alone. However, as with ATR, we detected delayed mammary gland development, evaluated by whole mount analysis, as early as PND4 in all treatment groups. Conclusions: Our data suggest that acute exposure to AMM at levels as low as 0.09 mg/kg bw during late pregnancy causes persistent alterations in mammary gland development of female off-spring, and that these effects do not appear to be related to bw or associated with pubertal timing.
We have determined the Hg removal capacities of Pt and Pd supported on alumina at a range of different metal loadings from 2 to 9
wt% using Hg vapour in a simulated fuel gas feed. In the temperature ...range studied (204–388
°C) Pd proved far superior to Pt for Hg removal. The Hg removal capacity for both Pt and Pd increased with metal loading, though decreased with sorbent temperature. A shift in the 2
θ position of the Pd XRD diffraction peak from 82.1 to 79.5 after Hg adsorption at 204
°C was consistent with the formation of a solid solution of Hg in Pd.
Previous studies in mice with multiple gestational exposures to perfluorooctanoic acid (PFOA) demonstrate numerous dose dependent growth and developmental effects which appeared to worsen if ...offspring exposed in utero nursed from PFOA-exposed dams. To evaluate the disposition of PFOA in the pregnant and lactating dam and her offspring, time-pregnant CD-1 mice received a single 0, 0.1, 1, or 5mg PFOA/kg BW dose (n=25/dose group) by gavage on gestation day 17. Maternal and pup fluids and tissues were collected over time. Pups exhibited significantly higher serum PFOA concentrations than their respective dams, and their body burden increased after birth until at least postnatal day 8, regardless of dose. The distribution of milk:serum PFOA varied by dose and time, but was typically in excess of 0.20. These data suggest that milk is a substantial PFOA exposure route in mice and should be considered in risk assessment modeling designs for this compound.
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