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Psoriasis was associated with vitiligo in two cases. In both cases, psoriatic lesions appeared sharply demarcated in vitiliginous skin. The phenomenon is regarded as a significant biologic response and more than a chance coincidence of the two diseases in the same location.

This book is a timely review of the current state of our knowledge of materials, particularly metals, and their uses in orthopedic surgery. It is divided into two parts. The first deals with the structure and properties of the materials themselves and the biologic response of tissues to their implantation. The chapter on the design, use, and care of implants is particularly valuable for surgeons and operating room personnel responsible for handling the implants before and during the operation. The second portion of the book deals with the applications to orthopedic surgery of the wide variety of materials. The use of materials in the treatment of fractures and reconstructive operations is considered in detail. Some might say that this portion of the book is redundant. However, the basic principles are well laid out, and their application to surgical practice is well illustrated by technical descriptions of the operative procedures. The

TUMOR NECROSIS FACTOR (TNF) is the most recent biologic response modifier to reach clinical trials in cancer therapy. Yet it is the direct descendant of one of the earliest attempts to provoke an antitumor immune response. The rationale for therapy with TNF—a protein secreted by macrophages challenged by bacterial endotoxins—dates to the late 1800s, when physicians noticed that cancer patients who had spontaneous tumor regression often also had bacterial infections. In 1893, a New York city physician, William Coley, MD, began to treat cancer patients with a cocktail of bacterial products, which came to be known as Coley's toxins. The patients usually developed high fevers, and, in some, tumors regressed. In 1934, the American Medical Association labeled Coley's toxins as the only known systemic treatment for cancer. But Coley's toxins proved to be less reliable in achieving remissions than did radiation and chemotherapy, and in the 1960s the treatment was

This and subsequent communications comprise a study of the factors which influence the biologic activity of radiation. The present paper deals with an explanation of the influence of the time factor on the response of tissue to measured quantities of radiation. The reaction medium has been the human skin in vivo, and the roentgen rays used were of low voltage and either unfiltered or slightly filtered. The biologic response of living substances to measured quantities of roentgen rays and gamma rays is recognized by many as depending on the intensity rate. The accepted meaning of the term intensity rate implies the quantity of radiation delivered in a unit of time and is expressed as roentgens divided by the time in which they are applied, or roentgen per minute. Probably the first published definite relation between biologic response and intensity rate was that of Holthusen in 1933. 1 He gave a

In our shipyards today we are employing over 100,000 welders. These workers and their neighbors have a certain amount of exposure to ultraviolet radiation, although every effort is made to supply and use suitable eye shields, goggles and screens. About 40 per cent of the calls at our shipyard dispensaries are because the patient has received what he thinks may be an "eye flash." 1 Our purpose in the present study was to derive a practical rule whereby one can estimate in terms of time, intensity of radiation and distance the safeness of any exposure to a welding arc. Verhoeff and Bell 2 showed that the ultraviolet radiations responsible for ocular lesions in rabbits were shorter than 305 millimicrons and that about 2 × 10 6 erg seconds per square centimeter were required for a minimal effect. They also showed that the biologic response varied with the duration of the

The exact mechanism by which bishydroxycoumarin (dicumarol®) affects the blood coagulation system is still unknown. The similarity in the chemical structure of 3-substituted 4-hydroxycoumarins to vitamin K led the original workers1to suggest that bishydroxycoumarin might act by blocking or competing with vitamin K in maintaining prothrombin activity. This hypothesis was supported by animal experiments which demonstrated the similarity of vitamin K deficiency to the biologic response to bishydroxycoumarin2and the ability of vitamin K to reverse the action of this drug.3However, it was clearly shown that the levels of 2-methyl-1, 4-naphthoquinone necessary to counteract the action of the anticoagulant are considerably larger