Publications by authors named "Timothy Irvine"

In this article we provide a method to isolate hair follicle stem cells that have undergone targeted gene inactivation. The mice from which these cells are isolated are bred into a Rosa26-yellow fluorescent protein (YFP) reporter background, which results in YFP expression in the targeted stem cell population. These cells are isolated and purified by fluorescence-activated cell sorting, using epidermal stem cell-specific markers in conjunction with YFP fluorescence.

View Article and Find Full Text PDF

Phagocytic melanosome uptake by epidermal keratinocytes is a central protective mechanism against damage induced by ultraviolet radiation. Phagocytosis requires formation of pseudopodia via actin cytoskeleton rearrangements. Integrin-linked kinase (ILK) is an important modulator of actin cytoskeletal dynamics.

View Article and Find Full Text PDF

Integrin-linked kinase (ILK) is key for normal epidermal morphogenesis, but little is known about its role in hair follicle stem cells and epidermal regeneration. Hair follicle stem cells are important contributors to newly formed epidermis following injury. We inactivated the Ilk gene in the keratin 15--expressing stem cell population of the mouse hair follicle bulge.

View Article and Find Full Text PDF

Integrin-linked kinase (ILK) plays key roles in a variety of cell functions, including cell proliferation, adhesion and migration. Within the cell, ILK localizes to multiple sites, including the cytoplasm, focal adhesion complexes that mediate cell adhesion to extracellular substrates, as well as cell-cell junctions in epidermal keratinocytes. Central to understanding ILK function is the elucidation of the mechanisms that regulate its subcellular localization.

View Article and Find Full Text PDF

The sensing of pathogen infection and subsequent triggering of innate immunity are key to controlling zoonotic infections. Myxoma virus (MV) is a cytoplasmic DNA poxvirus that in nature infects only rabbits. Our previous studies have shown that MV infection of primary mouse cells is restricted by virus-induced type I interferon (IFN).

View Article and Find Full Text PDF

Myxoma virus (MV) encodes a cell surface protein (M135R) that is predicted to mimic the host alpha/beta interferon receptor (IFN-alpha/beta-R) and thus prevent IFN-alpha/beta from triggering a host antiviral response. This prediction is based on sequence similarity to B18R, the viral IFN-alpha/beta-R from vaccinia virus (VV), which has been demonstrated to bind and inhibit type I interferons. However, M135R is only half the size of VV B18R.

View Article and Find Full Text PDF

Platypnoea orthodeoxia syndrome is a rare condition in which shortness of breath and hypoxaemia occur when upright and resolve when prone. The hypoxaemia results from increased right to left shunting of deoxygenated blood, when standing, through a patent foramen ovale (PFO), atrial septal defect (ASD) or other right to left shunt, in the absence of raised right-heart pressure. We present the case of a patient with platypnoea orthodeoxia with marked shunting through a large PFO, evaluated by transesophageal and transthoracic echo.

View Article and Find Full Text PDF

Many viruses inhibit or retard apoptosis, a strategy that subverts one of the most ancient antiviral mechanisms. M11L, a myxoma virus-encoded antiapoptotic protein, has been previously shown to localize to mitochondria and block apoptosis of virus-infected cells (H. Everett, M.

View Article and Find Full Text PDF

Objective: The purpose of our study was to test the applicability of calculating the difference between left ventricular (LV) and right ventricular (RV) stroke volume (SV) for assessing the severity of aortic (Ao) regurgitation (AR) using a real-time 3-dimensional (3D) echocardiographic (RT3DE) imaging system.

Methods: The Ao valve was incised in 5 juvenile sheep, 6 to 10 weeks before the study, to produce AR (mean regurgitant fraction = 0.50).

View Article and Find Full Text PDF

Objectives: The purpose of the present study was to validate a newly developed three-dimensional (3D) digital color Doppler method for quantifying pulmonary regurgitation (PR), using an animal model of chronic PR.

Background: Spectral Doppler methods cannot reliably be used to assess pulmonary regurgitation.

Methods: In eight sheep with surgically created PR, 27 different hemodynamic states were studied.

View Article and Find Full Text PDF

Accurately quantifying transmitral flow volume is clinically important not only as a measure of cardiac output, but also as a value from which to subtract aortic flow, for determining the severity of mitral regurgitation. However, controversy exists over the accuracy of pulsed Doppler for mitral flow quantification because of the complexity of mitral flow geometry and dynamic changes in flow profile and flow area. To explore the feasibility of directly quantifying transmitral flow volume with a newly developed dynamic 3-dimensional digital color Doppler technique, this in vivo experimental study was conducted to validate the method.

View Article and Find Full Text PDF