Effects of breastfeeding on body composition and maturational tempo in the rat

BACKGROUND: Features of life history are subject to environmental regulation in the service of reproductive fitness goals. We have previously shown that the infant-to-childhood transition reflects the adaptive adjustment of an individual's size to the prevailing and anticipated environment. METHODS: To evaluate effects of weaning age on life-history traits in rats, we repeatedly measured length and body mass index (BMI), as well as physiological development and sexual maturation in pups weaned early (d16), normally (d21) or late (d26). Males were bred to females of the same weaning age group for four generations. RESULTS: Here, we show that the age at weaning from lactation regulates a rat's life history, growth, body composition and maturational tempo. We show that early-weaned rats developed faster than normal- or late-weaned rats; they are leaner and longer than late-weaned ones who are heavier and shorter. Early-weaned progeny develop more rapidly (that is, fur budding, pinnae detachment, eye opening); females show earlier vaginal opening and estrous and males show earlier onset of testicular growth. In generations 3 and 4, early-weaned rats bear larger litter sizes and heavier newborn pups. The entire traits complex is transmitted to subsequent generations from the paternal side. CONCLUSIONS: The findings presented here lend support to the proposition that the duration of infancy, as indexed by weaning age, predicts and perhaps programs growth, body composition, and the tempo of physiological development and maturation, as well as litter size and parity and, thereby, reproductive strategy

Autoregulation of E-cadherin expression by cadherin–cadherin interactions: the roles of β-catenin signaling, Slug, and MAPK

Transcriptional repression of E-cadherin, characteristic of epithelial to mesenchymal transition, is often found also during tumor cell invasion. At metastases, migratory fibroblasts sometimes revert to an epithelial phenotype, by a process involving regulation of the E-cadherin–β-catenin complex. We investigated the molecular basis of this regulation, using human colon cancer cells with aberrantly activated β-catenin signaling. Sparse cultures mimicked invasive tumor cells, displaying low levels of E-cadherin due to transcriptional repression of E-cadherin by Slug. Slug was induced by β-catenin signaling and, independently, by ERK. Dense cultures resembled a differentiated epithelium with high levels of E-cadherin and β-catenin in adherens junctions. In such cells, β-catenin signaling, ErbB-1/2 levels, and ERK activation were reduced and Slug was undetectable. Disruption of E-cadherin–mediated contacts resulted in nuclear localization and signaling by β-catenin, induction of Slug and inhibition of E-cadherin transcription, without changes in ErbB-1/2 and ERK activation. This autoregulation of E-cadherin by cell–cell adhesion involving Slug, β-catenin and ERK could be important in tumorigenesis

Expression of the ???6 integrin promotes migration and invasion in squamous carcinoma cells

The integrin αvβ6 is a fibronectin receptor whose expression is not detectable on normal oral epithelium but is increased significantly in healing and in oral epithelial dysplasia and oral squamous cell carcinoma, suggesting it may promote changes associated with tumor development. To study whether αvβ6 may drive invasive behavior we have used transfection and retroviral infection to create a panel of epithelial cell lines expressing various levels of αvβ6. We report that increased expression of αvβ6 in malignant keratinocytes promotes invasion and leads to an increased capacity for migration towards fibronectin. αvβ6 expression may have a significant role in contributing to the malignant behavior of epithelial cells

When people fall from grace: Reconsidering the role of envy in Schadenfreude

Previous research yielded conflicting results concerning the role of envy in predicting Schadenfreude (pleasure at another's misfortune). Some studies showed that envy predicts Schadenfreude, whereas others did not. Results of the present research reconcile these opposing findings, by showing that envy is a predictor of Schadenfreude when the target is similar to the observer in terms of gender. These results suggest that envy predicts Schadenfreude when people are confronted with the misfortune of a relevant social comparison other. Copyright 2006 by the American Psychological Association

The expression pattern of Β-catenin in mesothelial proliferative lesions and its diagnostic utilities

Β-Catenin is a component of the E-cadherin-catenin cell adhesion complex. It plays an important role in the Wnt/wg pathway, which conveys critical signals for cell proliferation and transformation. The Β-catenin mutation is an important event in the progression of a number of malignancies. In this study, we evaluated the immunohistochemical (IHC) pattern of Β-catenin in a spectrum of mesothelial lesions. Sixty-five formalin-fixed, paraffin-embedded blocks from 54 serous effusions and 11 pleural biopsies were examined. These cases consisted of 33 invasive mesotheliomas, 9 early mesotheliomas (with negative radiologic finding), so-called mesotheliomas in situ, and 23 reactive mesothelial proliferations. A distinct membranous and/or submembranous staining pattern was seen in 23 cases with normal and reactive mesothelium. In contrast, reduced membranous and/or submembranous antibody staining and markedly increased ectopic cytoplasmic and nuclear staining was seen in 26 cases of 33 mesotheliomas. Seven of 9 early mesotheliomas showed increased ectopic cytoplasmic and/or nuclear stain. On the basis of our findings, identification of Β-catenin staining pattern offers a useful marker in the diagnosis of mesothelial lesions and may help identify neoplastic change. Diagn. Cytopathol. 2005;33:320–324. © 2005 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48781/1/20281_ftp.pd