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

Coordinating changes in cell adhesion and phenotype during EMT-like processes in cancer

Understanding the progression of a primary cancer to the metastatic stage has been the focus of extensive research for years. Commonly accepted concepts in this process (i.e., that of genetic instability and loss of normal cellular constraints on growth and motility) are well established. Other important paradigms, such as the necessary change from an epithelial cell phenotype displaying cell-cell adhesions to a singular and motile mesenchymal-like cell phenotype (possibly derived from a stem cell-like cell) via a process similar to epithelial to mesenchymal transition (EMT), are less well understood. In this review we will address studies linking EMT and cancer stem cells during cancer development and observations that are challenging these concepts

The modern search for the Holy Grail: Is neuroscience a solution?

Neuroscience has become prevalent in recent years; nevertheless, its value in the examination of psychological and philosophical phenomena is still a matter of debate. The examples reviewed here suggest that neuroscientific tools can be significant in the investigation of such complex phenomena. In this article, we argue that it is important to study concepts that do not have a clear characterization and emphasize the role of neuroscience in this quest for knowledge. The data reviewed here suggest that neuroscience may (1) enrich our knowledge; (2) outline the nature of an explanation; and (3) lead to substantial empirical and theoretical discoveries. To that end, we review work on hedonia and eudaimonia in the fields of neuroscience, psychology, and philosophy. These studies demonstrate the importance of neuroscientific tools in the investigation of phenomena that are difficult to define using other methods

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

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

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