The estrogen-injected female mouse: new insight into the etiology of PCOS

<p>Abstract</p> <p>Background</p> <p>Female mice and rats injected with estrogen perinatally become anovulatory and develop follicular cysts. The current consensus is that this adverse response to estrogen involves the hypothalamus and occurs because of an estrogen-induced alteration in the GnRH delivery system. Whether or not this is true has yet to be firmly established. The present study examined an alternate possibility in which anovulation and cyst development occurs through an estrogen-induced disruption in the immune system, achieved through the intermediation of the thymus gland.</p> <p>Methods, Results and Conclusion</p> <p>A putative role for the thymus in estrogen-induced anovulation and follicular cyst formation (a model of PCOS) was examined in female mice by removing the gland prior to estrogen injection. Whereas all intact, female mice injected with 20 ug estrogen at 5–7 days of age had ovaries with follicular cysts, no cysts were observed in animals in which thymectomy at 3 days of age preceded estrogen injection. In fact, after restoring immune function by thymocyte replacement, the majority of thymectomized, estrogen-injected mice had ovaries with corpora lutea. Thus, when estrogen is unable to act on the thymus, ovulation occurs and follicular cysts do not develop. This implicates the thymus in the cysts' genesis and discounts the role of the hypothalamus. Subsequent research established that the disease is transferable by lymphocyte infusion. Transfer took place between 100-day-old estrogen-injected and 15-day-old naïve mice only when recipients were thymectomized at 3 days of age. Thus, a prerequisite for cyst formation is the absence of regulatory T cells. Their absence in donor mice was judged to be the result of an estrogen-induced increase in the thymus' vascular permeability, causing de facto circumvention of the final stages of regulatory T cell development. The human thymus has a similar vulnerability to steroid action during the fetal stage. We propose that in utero exposure to excessive levels of steroids such as estrogen has a long-term effect on the ability of the thymus to produce regulatory T cells. In female offspring this can lead to PCOS.</p

Public Choice DOI 10.1007/s11127-012-0032-z Candidate positioning and responsiveness to constituent opinion in the U.S. House of Representatives

Abstract In this paper, I develop a survey-based measure of district ideology for the House of Representatives. I use this index to document and study ways in which patterns of candidate positioning depart from perfect representation. These findings help distinguish between competing theories of candidate positioning. My findings present evidence against theories that attribute divergence to the preferences of voters and the locations of primary constituencies. My findings are potentially consistent with the policy-motivation and resource theories, which attribute divergence to the polarization of political elites

Benchmarking across Borders: An Update and Response

Arel-Bundock, Blais and Dassonneville (2018, ABD hereafter) offer an unusual critique of our 12 article, Benchmarking across Borders. They find no methodological flaws, produce identical 13 empirical results and concede that their proposed specification (Model 5) is mathematically 14 identical to that used in Kayser and Peress (2012, KP hereafter). ABD make two claims: (1) that 15 their preferred specification is an innovation that improves interpretation and (2) that the 16 empirical evidence presented in KP does not support benchmarking. The first is unpersuasive 17 and the second depends on a selective reading of the evidence. We address these issues below and 18 update the individual-level dataset from KP to increase statistical power, finding additional 19 evidence of benchmarking

Scaling the Critics: Uncovering the Latent Dimensions of Movie Criticism With an Item Response Approach

Achen and Alastair Smith. Peress thanks the Institute of Quantitative Social Science for hospitality. We are very grateful for comments from two anonymous referees and the AE at JASA that helped us improve the content and structure of our paper

Replication Data for Benchmarking across Borders: An Update and Response

Replication Data for Benchmarking across Borders: An Update and Respons

Household Sorting and Neighborhood Formation

We develop a new model of household sorting in a system of residential neighborhoods. We show that this model is partially identified without imposing parametric restrictions on the distribution of unobserved tastes for neighborhood quality and the shape of the indirect utility function. The proof of identification is constructive and can be used to derive a new semiparameteric estimator. Our empirical application focuses on residential choices and housing demand in a system of neighborhoods in the Pittsburgh metropolitan area. We find that there are significant differences in the observed sorting of households with and without children. In particular, households with children exhibit more stratification by income than households without children

Identification and Semiparametric Estimation of Equilibrium Models of Local Jurisdictions

We develop a new model of household sorting in a system of residential neighborhoods. We show that this model is partially identified without imposing parametric restrictions on the distribution of unobserved tastes for neighborhood quality and the shape of the indirect utility function. The proof of identification is constructive and can be used to derive a new semiparameteric estimator. Our empirical application focuses on residential choices in the Pittsburgh metropolitan area. We find that sorting of households with children exhibit more stratification by income than sorting of households without children. (JEL C51, D12, H41, J12, R21, R23)