Since W. D. Hamilton's seminal work on the evolution of sociality, a large body of research has accumulated on how kin selection might explain the evolution of cooperation in many group-living species. Our study examined the evolutionary basis of philopatry and cooperation; specifically, whether individuals benefit from the presence of close kin. We applied an individual fitness approach to a 1...

1. Young rats were kept in a hypoxic chamber for 2-11 weeks and compared with littermate control animals. 2. The carotid bodies of the hypoxic rats enlarged, resembling those of men and animals living at high altitude. 3. Permanent blunting of the ventilatory response to hypoxia did not occur. Immediately on removal from the chamber, the rats, lightly anaesthetized, showed a smaller increase in...

Neuregulin-1 (NRG-1), binding to the human epidermal growth factor receptor HER2/HER3, plays a role in pulmonary epithelial cell proliferation and recovery from injury in vitro. We hypothesized that activation of HER2/HER3 by NRG-1 would also play a role in recovery from in vivo lung injury. We tested this hypothesis using bleomycin lung injury of transgenic mice incapable of signaling through ...

Insulin-like growth factor-I (IGF-I) has been implicated in postnatal alveolar development, pulmonary fibrosis, and non-small cell lung cancer. To further investigate the role of IGF-I, we created a line of transgenic mice in which alveolar type II epithelial cells express human IGF-IA under the control of the surfactant protein C promoter. We determined the effect of pulmonary overexpression o...

PURPOSE To investigate the effect of c-fos on apoptotic cell death and regeneration of damaged retinal ganglion cells (RGCs) in tissue culture of retinal explants. METHODS Retinas from transgenic mice carrying the exogenous c-fos gene under the control of the interferon (IFN)-alpha/beta inducible Mx-promoter (Mx-c-fos), c-fos-deficient mice, and littermate control mice were dissected and cult...

Stable mixed donor/host hematopoietic chimerism can be accomplished in dog leukocyte antigen (DLA)-identical littermate dogs given sublethal (200 cGy) total-body irradiation (TBI) before and immunosuppression with mycophenolate mofetil (MMF) and cyclosporine (CSP) after transplant (Blood 89:3048, 1997). Studies were based on the hypothesis that drugs that prevent graft-versus-host disease (GVHD...

To examine the role of sarcolemmal K(ATP) channels in cardiac function, we generated transgenic mice expressing GFP-tagged Kir6.2 subunits with reduced ATP sensitivity under control of the cardiac alpha-myosin heavy chain promoter. Four founder mice were isolated, and both founders and progeny were all apparently normal and fertile. Electrocardiograms from conscious animals also appeared normal...

BACKGROUND AND PURPOSE Folate deficiency and resultant hyperhomocysteinemia impair vascular function and increase stroke risk. We tested the hypothesis that folate deficiency and high homocysteine levels promote DNA damage and increase brain injury after cerebral ischemia/reperfusion. METHODS 129/Sv mice, uracil-DNA glycosylase-deficient (Ung-/-) mice, and Ung+/+ littermate mice were exposed ...

Caloric restriction of mammals leads to decreases in blood pressure and heart rate. Although relevant clinically, the mechanisms involved, in terms of hormones and signaling pathways invoked, are currently not known. Circumstantial evidence suggests that leptin signaling may be involved with the bradycardia and hypotension associated with caloric restriction. This hypothesis was specifically te...

Days 9 to 12 of gestation in the pig are marked by a pronounced asynchrony among littermate embryos. Previously published studies have suggested that the most advanced embryos within a litter by d 12 synthesize greater amounts of estrogen. Embryonic estrogen secretion has been shown to advance endometrial secretions, which may adversely affect less-developed littermates. To date, however, no co...