Biomedical subjects

Blair Henderson

Publications and source records attributed to Blair Henderson.

6 recordsLinked to original sources

PubMed2006

Increased serum cadmium and strontium levels in young smokers: effects on arterial endothelial cell gene transcription.

OBJECTIVE: Metal constituents of tobacco have long been suspected to contribute to cardiovascular diseases. In this study, we determined the serum concentrations of aluminum, cadmium (Cd), cobalt, copper, iron, manganese, nickel, lead, strontium (Sr), and zinc of young nonsmokers, passive smokers, and smokers. METHODS AND RESULTS: Cd and Sr were found to be significantly increased in smokers compared with nonsmokers. The effects of these metals on primary arterial endothelial cells were then assessed using microarray technology and real-time polymerase chain reaction (RT-PCR). The data showed that Sr does not interfere with endothelial cell transcription. In contrast, the effects of Cd in amounts delivered to the human body by smoking were dramatic. CONCLUSIONS: Arterial endothelial cells responded to Cd exposure by massively upregulating metal and oxidant defense genes (metallothioneins) and by downregulating a number of transcription factors. In addition, the mRNA of the intermediate filament protein vimentin, crucial for the maintenance of cellular shape, was reduced. Surprisingly, a number of pro-inflammatory genes were downregulated in response to Cd. The present data suggest that by delivering Cd to the human body, smoking deregulates transcription, exerts stress, and damages the structure of the vascular endothelium; furthermore, in contrast to the effects of cigarette smoke as a whole, Cd seems to possess anti-inflammatory properties.

Adult↗

PubMed2006

Gene expression profiling of human endothelial cells exposed to 50-Hz magnetic fields fails to produce regulated candidate genes.

To address the question of a possible effect of magnetic fields (MF) at 50 Hz on living systems, gene expression analyses were performed on human primary vascular endothelial cells exposed to MF of various intensities compared to control cells. Exposure protocols included continuous exposure at a single intensity (10 and 700 microT), intermittent exposure at a single intensity (700 microT), and continuous exposure to a variable-intensity field (10-30 microT). The transcriptional response of the cells was investigated using oligonucleotide microarrays containing up to 30 000 unique features. Although in individual experiments genes were identified where the expression appeared to be affected by exposure to MF, none of these genes were regulated in the same manner in subsequent repetition experiments. This is the first report of a transcriptome-wide analysis of the effects of MF exposure on human cells. The lack of a reproducible effect of MF on the expression of any genes in our investigation adds further weight to the evidence that 50-Hz MF are not capable of interacting with biological systems and thus do not represent an endothelial stress factor.

Cell Culture Techniques↗

PubMed2005

Cigarette smoke metal-catalyzed protein oxidation leads to vascular endothelial cell contraction by depolymerization of microtubules.

Smoking is a significant risk factor for development of atherosclerosis. However, the pathophysiology of smoking-mediated vessel wall damage is not understood. With tools ranging from analytical chemistry to cell biology, we show that cigarette smoke contains metals that catalyze the direct oxidation of cellular proteins by smoke oxidants. Oxidation of cellular proteins causes a loss of microtubule function, culminating in microtubule depolymerization and proteasome-dependent degradation of alpha-tubulin. As a consequence of the microtubule collapse, cytoskeletal structures as well as intermediate filaments break down, leading finally to a contraction of vascular endothelial cells. We observed a smoke extract-induced, calpain-dependent degradation of the intracellular form of platelet-endothelial cell adhesion molecule 1/CD31, as well as a release of P-selectin/CD62P, IL-6, and IL-8 from endothelial cells into the supernatant. Increased levels of soluble CD62P and IL-6 are well known to be associated with smoking in humans. Increased permeability of the vascular endothelium is a crucial event in atherogenesis. This work highlights the compounds and mechanisms by which cigarette smoke induces leakiness of the vascular endothelium.

Acetylcysteine↗

PubMed2004

A cost-effective web-based teaching file system.

Teaching files are common in radiology. Although there is an increasing role of digital technology in radiology departments, today's teaching files have not yet seen the application of this new technology. This may have been due in part to poor or incomplete implementation in many commercial software packages. We have demonstrated that by utilizing free software from the Internet, a web-based teaching file system, which is easy to use, low cost, and secure, can be created.

Cost-Benefit Analysis↗

PubMed2003

Progression of arteriovenous bypass restenosis in mice exposed to a 50 Hz magnetic field.

The controversy over whether magnetic fields (MF) produced by electrical wiring and appliances contribute to diseases such as cancer has been debated in the literature for more than 2 decades. These extremely low frequency fields at 50 or 60 Hz are omnipresent in the industrialized world and have been linked to various forms of cancer by epidemiological studies. Little has been published investigating any possible role of MF and cardiovascular disease, and this is the first study looking specifically at the effect of exposure to high-intensity MF on the development and progression of restenosis. A mouse arteriovenous bypass model was used, and mice were exposed to MF for periods of 1, 2, or 3 weeks. Neointima formation, infiltration of mononuclear cells, and heat shock protein 60 expression were all studied at the conclusion of the exposure regimen. Animals exposed to the MF for 1 week showed significantly smaller neointima formation compared with control mice exposed to a null field, although this difference was not observed in mice exposed for 2 or 3 weeks. No difference was found between mice exposed to MF and controls in any of the other parameters investigated.

Animals↗

PubMedDate not supplied

Development and evaluation of an in vitro model for the analysis of cigarette smoke effects on cultured cells and tissues.

INTRODUCTION: Smokers have an increased risk for a variety of diseases. Among the most prominent is atherosclerosis, the leading cause of death in the Western world. Although this conjunction is accepted knowledge, the basic biological mechanisms and the identities of the active tobacco smoke constituents surprisingly are still unknown. One reason for this is the lack of accurate in vitro models. METHODS: Cell culture experiments, including cell morphology and cell death analyses, high-performance liquid chromatography, and liquid chromatography coupled to mass spectrometry via an electrospray ionization interface allowing collision-induced dissociation analyses, were applied. RESULTS AND DISCUSSION: In this study, we present and validate an in vitro model that has proven to be useful for standardized studies of cellular and histological effects of cigarette smoke. The system consists of a cigarette smoke sampling device in which water-soluble cigarette smoke constituents pass over from the gas phase into the aqueous phase resulting in nicotine concentrations identical to the in vivo concentrations, suggesting in vivo similar conditions for gas-to-liquid compound exchange.

Cell Survival↗