Current Topics in Membranes

This e-book will review special features of the cerebral circulation and how they contribute to the physiology of the brain. It describes structural and functional properties of the cerebral circulation that are unique to the brain, an organ with high metabolic demands and the need for tight water and ion homeostasis. Autoregulation is pronounced in the brain, with myogenic, metabolic and neurogenic mechanisms contributing to maintain relatively constant blood flow during both increases and decreases in pressure. In addition, unlike peripheral organs where the majority of vascular resistance resides in small arteries and arterioles, large extracranial and intracranial arteries contribute significantly to vascular resistance in the brain. The prominent role of large arteries in cerebrovascular resistance helps maintain blood flow and protect downstream vessels during changes in perfusion pressure. The cerebral endothelium is also unique in that its barrier properties are in some way more like epithelium than endothelium in the periphery. The cerebral endothelium, known as the blood-brain barrier, has specialized tight junctions that do not allow ions to pass freely and has very low hydraulic conductivity and transcellular transport. This special configuration modifies Starling's forces in the brain microcirculation such that ions retained in the vascular lumen oppose water movement due to hydrostatic pressure. Tight water regulation is necessary in the brain because it has limited capacity for expansion within the skull. Increased intracranial pressure due to vasogenic edema can cause severe neurologic complications and death.

There has been a dramatic increase in knowledge of tight junctions in the past decade. The molecular structure of tight junctions, cellular functions and the pathophysiological roles of tight junctions are becoming clear. Of the most important functions, the role of the cellular structure in cancer spread and drug delivery are increasingly realised. It is now clear that there are fundamental changes to tight junctions during the process of cancer development. Tight junctions are also critical to the metastatic process of cancer cells. The cellular structure is also crucial in drug therapies, namely, the permeability and bioavailability of the drugs, penetration of barriers such as the blood brain barrier. This current volume aims to summarise the current knowledge of tight junctions, their role in cancer and cancer metastasis and is of interest to scientists and clinicians.

This book was written by many outstanding investigators who have spent decades to study different aspects of blood‐tissue barrier function. They have summarized some of the latest and fascinating development in their fields of research including the blood‐brain barrier, the blood‐retinal barrier, the gut barrier, the blood‐biliary barrier, the blood‐follicle barrier, the blood‐epididymis barrier, the blood‐testis barrier, the tight junction barrier in general as well as barriers in the female reproductive tract. Included are also chapters that focus on topics that are physiologically applicable to all blood‐tissue barriers. Many of these chapters also include information on specific human diseases, such as pathological changes of the gut barrier that cause bowel disorders resulting from inflammation of the epithelial lining in the intestine, and infertility in men as a result of disruption of the blood‐epididymal and/or blood‐testis barriers; and on new therapeutic approaches (e.g., drug delivery across the blood‐brain and the blood‐retinal barriers).

Development of moisturizers is a scientific and artistic discipline, where consumer insights are also needed. This new book bridges the gap between the moisturizers and the skin by covering all the essential information required to tailor the use of moisturizers to particular disorders and patients. Important aspects of skin biochemistry and barrier function are explained, and the ingredients and treatment effects of moisturizers are explored in depth. Careful attention is paid to controversies, including the role of certain moisturizers in inducing dryness/eczema, asthma, and comedones. The information provided in this unique book will enable the reader to go beyond the traditional thinking regarding skin care. The novel insights offered will suggest the properties required for a new generation of moisturizing treatments that more effectively improve the quality of life.

“Infogest” (Improving Health Properties of Food by Sharing our Knowledge on the Digestive Process) is an EU COST action/network in the domain of Food and Agriculture that will last for 4 years from April 4, 2011. Infogest aims at building an open international network of institutes undertaking multidisciplinary basic research on food digestion gathering scientists from different origins (food scientists, gut physiologists, nutritionists...). The network gathers 70 partners from academia, corresponding to a total of 29 countries. The three main scientific goals are: Identify the beneficial food components released in the gut during digestion; Support the effect of beneficial food components on human health; Promote harmonization of currently used digestion models Infogest meetings highlighted the need for a publication that would provide researchers with an insight into the advantages and disadvantages associated with the use of respective in vitro and ex vivo assays to evaluate the effects of foods and food bioactives on health. Such assays are particularly important in situations where a large number of foods/bioactives need to be screened rapidly and in a cost effective manner in order to ultimately identify lead foods/bioactives that can be the subject of in vivo assays. The book is an asset to researchers wishing to study the health benefits of their foods and food bioactives of interest and highlights which in vitro/ex vivo assays are of greatest relevance to their goals, what sort of outputs/data can be generated and, as noted above, highlight the strengths and weaknesses of the various assays. It is also an important resource for undergraduate students in the ‘food and health’ arena.