R. Marks – författare

The two closely related species of Potato Cyst-Nematodes (PCN), Globodera rostochiensis (Woll) and Globodera pallida Stone have a worldwide distribution. Both are internationally recognized plant quarantine organisms of actual or potential major economic importance wherever potatoes are grown or traded. They occur in large soil masses and also adhere to potato tubers as microscopic cysts, which represent a complex of morphologically identical, but behaviourally different virulence groups, or pathotypes. This presents major problems for their detection, identification and management. This book is a synthesis of current practical knowledge and underpinning scientific research on PCN globally. It is arranged in five sections, comprising nineteen chapters by leading practitioners and research nematologists, in which the biology, detection, identification and control options (including plant resistance) for PCN are examined. In addition, its worldwide status is considered, including South America, where PCN co-evolved with its potato host. Essential information is provided for professionals and advanced students of plant nematology and crop protection.

R. MARKS Biology has become a 'numbers game'. The advantages of being able to grade changes in tissue, submit results to statistical analysis and accurately record biological phenomena make measurement essential. This is as true for the various disciplines in applied biology as it is for the more esoteric aspects ofthe subject. Regrettably, sk in biologists until recently had not seized the opportunities that the availability of their tissue of interest afforded and fell behind in the exploration of measurement techniques. Probably this resulted in part from the mistaken sentiment that 'to see is to know'. It also originated from the complexity ofthe skin which. as a closely interwoven mixture oftissue types. makes assessments technically difficult. However, we are optimistic about the future. The International Society for Bioengineering and the Skin was formed in Cardiff in ] uly 1979 in response to the wishes of the delegates who had attended the first International Symposium on the subject in Miami in 1976 and the second in Cardiff 3 years later. This volume is the proceedings of the Cardiff meeting. We believe that it demonstrates the brave efforts and variety of new ideas that characterise the studies of scientists who realise the importance of blending the phYSICal sciences with skin biology.

The stratum corneum is a magnificent example of the successful adaptation of a tissue. Its efficient function is a prerequisite for life itself. We depend on its control of the movement of water through the skin and on its protective role in the prevention of penetration by pathogens or harmful substances. Apart from its functional importance, there is no escaping the fact that the most common skin disorders (psoriasis, eczema, inherited disorders of keratinization, acne) are 'characterised by abnormal keratinization and or scaliness. Despite all this, understanding of its chemistry, structure, physiology and involvement in disease has been sadly deficient; however, there are signs of enlightenment. This symposium is evidence of changed atti· tudes. Leading researchers from many countries have applied modem biomedical techniques and the methods of molecular biology to the many problems and questions posed by the stratum corneum. Although there have been several symposia and publications on the process of keratinization, few have been broadly based on the stratum corneum. For this reason we believe that the proceedings of this symposium will be invaluable for all who are profeSSionally concerned with skin biology. Cardiff/Diisseldorf, November 1982 R. Marks G. Plewig v Acknowledgements Alcon Labs. Limited Brocades G. B. Limited Cardiff City Council Cassella-Riedel Pharma GmbH. Cilag-Chemie Dermal Laboratories Limited Dista Products Limited Dome Div. Miles Laboratories Limited Hoechst AG. Imperial Chemical Industries Limited Janssen Pharmaceuticals Limited Johnson & Johnson Limited L'Oreal E.

R. MARKS Biology has become a 'numbers game'. The advantages of being able to grade changes in tissue, submit results to statistical analysis and accurately record biological phenomena make measurement essential. This is as true for the various disciplines in applied biology as it is for the more esoteric aspects ofthe subject. Regrettably, sk in biologists until recently had not seized the opportunities that the availability of their tissue of interest afforded and fell behind in the exploration of measurement techniques. Probably this resulted in part from the mistaken sentiment that 'to see is to know'. It also originated from the complexity ofthe skin which. as a closely interwoven mixture oftissue types. makes assessments technically difficult. However, we are optimistic about the future. The International Society for Bioengineering and the Skin was formed in Cardiff in ] uly 1979 in response to the wishes of the delegates who had attended the first International Symposium on the subject in Miami in 1976 and the second in Cardiff 3 years later. This volume is the proceedings of the Cardiff meeting. We believe that it demonstrates the brave efforts and variety of new ideas that characterise the studies of scientists who realise the importance of blending the phYSICal sciences with skin biology.

Substances that are applied to the skin to heal it, make it feel better or improve its appearance, have much in common. They can all do damage to the skin as well as perform the task for which they were designed. They and the substances they contain are all absorbed through the skin to a greater or lesser extent. In addition, all these agents are constructed in the same general way. For these reasons it seems odd and uneconomical to consider topical pharmaceuticals, toiletry products and cosmetics separately. This was the reasoning behind the holding of a small symposium of workers involved with one or another aspect of the formulation of substances destined for application to the skin. Several aspects of the subject are covered in this book which is based on the symposium and the contents should be of interest to all who are concerned with the prescription, assess­ ment or formulation of topical agents. 9 1 Acne Caused and Treated by Topical Agents W. J. CUNLIFFE The four main aetiological factors involved in the development of l acne are (1) an elevated sebum excretion rate ; (2) ductal hyper­ 3 keratinization 2; (3) an abnormality of microbial function ; (4) host 4 inflammatory response • Although opinions differ on both sides of the Atlantic, most authorities in the United Kingdom believe that increased sebum excretion rate is the main drive to acne, there being a definitive relationship between the severity of the acne and the seborrhoea of this disease.