The evolution of current medical and popular attitudes toward ultraviolet light exposure: part 3.

In the 1930s, attitudes toward ultraviolet (UV) light exposure began to change significantly within the medical profession. UV radiation had been promoted as healthful since the century's start, and particularly after the discovery of its role in vitamin-D metabolism. Increasingly, however, attention would focus on the risks of UV light exposure from sunlamps and sunbathing. During this time, the American Medical Association established guidelines for the approval of UV lamps and the appropriate therapeutic uses of phototherapy. The landmark experiments of Findlay and other researchers, in which malignant skin tumors were induced in rodents after exposure to UV lamps or sunlight, would lead to widespread recognition of the carcinogenicity of UV radiation. The role of sunlight in the etiology of skin cancer was increasingly mentioned in articles in popular magazines in the 1940s and 1950s. There was rapid growth of the sunscreen industry as well, although product efficacy remained highly variable. In the 1950s, interest developed in the use of 8-methoxypsoralen ("the suntan pill") and dihyroxyacetone ("suntan in a bottle"). In spite of the known risks of UV exposure and attempts by physicians and other health professionals to educate the public and modify behavior, suntanning has remained tenaciously popular. Today, excessive UV light exposure is recognized as the major cause of the approximately 1.3 million cases of skin cancer in the United States each year.

Keratinocyte carcinoma.

Keratinocyte carcinoma is by far the most common cancer in the United States. Basal cell carcinomas and squamous cell carcinomas account for approximately 80% and 20% of cases of KC, respectively. The term nonmelanoma skin cancer is commonly used to refer to squamous cell carcinomas and basal cell carcinomas; however, other types of nonmelanoma skin cancer, such as adnexal tumors and sarcomas, are less common and differ in their cell type, behavior, and epidemiologic features from KC. Primary care clinicians are well positioned to diagnose KC and to educate patients about preventive measures such as sun protection and self-examination. Here we review epidemiologic data and strategies for prevention, diagnosis, and clinical management of KC.

The evolution of current medical and popular attitudes toward ultraviolet light exposure: part 2.

The 1920s and 1930s represented an extraordinary time in the shaping of modern attitudes towards ultraviolet light. Dermatologists and other physicians today are still confronting the effects of changes in social behavior that occurred at this time. The discovery that ultraviolet wavelengths played a role in vitamin D synthesis in the skin ushered in a period of enormous popularity for ultraviolet light exposure. A variety of other medical claims were soon made for ultraviolet radiation, including that it increased resistance to disease. The field of phototherapy rapidly expanded, and its use was employed by proponents for a host of unlikely medical conditions. Exposure to sunlight or ultraviolet lamps was widely promoted as a form of preventive medicine. Home sunlamps gained popularity and were aggressively marketed to the public. A suntan, which had previously achieved limited popularity, now was viewed as de rigueur in the United States and Europe. The role that medical advocacy of ultraviolet light exposure played in initially advancing the practice of sunbathing is not commonly appreciated today. Ironically, public health recommendations of the time were often diametrically opposed to those being made at present, since sunlight exposure is currently recognized as the major preventable cause of cancer of the skin.

Smallpox manifestations and survival during the Boston epidemic of 1901 to 1903.

Clinical records of 243 patients with smallpox consecutively admitted to the Southampton Street smallpox hospital in Boston, Massachusetts, during the 1901-1903 epidemic were reviewed. Smallpox was divided into five categories of varying severity; 47% of patients had varioloid, a relatively mild form of the disease usually occurring in previously vaccinated individuals with incomplete immunity. Survival information is available for 206 patients, of whom 36 (17.5%) died. Vaccination status, disease severity, and age were associated with survival, whereas sex, birthplace, and race were not. While full recovery often took weeks, most deaths occurred 7 to 14 days after the onset of symptoms, and all deaths occurred within 18 days of symptom onset. Smallpox was eradicated worldwide in 1977, but knowledge of the disease is essential because its cause, variola virus, is considered a potential biological weapon.

The evolution of current medical and popular attitudes toward ultraviolet light exposure: part 1.

Ultraviolet radiation is the most important carcinogenic agent related to the development of melanoma and nonmelanoma skin cancer, and primary prevention efforts focus on reducing exposure to sunlight and ultraviolet sunlamps. Favorable societal views of suntanning serve as an obstacle to skin cancer prevention. Although the education of patients and the public regarding the risks of excessive ultraviolet light exposure is an important goal in medicine today, few physicians have more than a vague knowledge of how current attitudes actually developed during the past century. Opinions about ultraviolet light exposure were not static, but evolved with increasing scientific knowledge and changing social mores. A critical interplay occurred between the prevailing medical and nonmedical views on the subject. In this article, we focus on the century's start (1900-1920)--a time when vigilance against significant sun exposure, a relic of the 19th century, was eroding, and the roots of later attitudes toward sunbathing were already manifest. Medically, the view of sunlight as salutary was bolstered by the success of phototherapy, which was introduced in the 1890s. The first clinical observations associating long-term sunlight exposure with skin cancer were also reported during this time. The association, however, was poorly understood, and this work was largely ignored by the medical profession and remained essentially unknown to the public.

Absence of donor-derived keratinocyte stem cells in skin tissues cultured from patients after mobilized peripheral blood hematopoietic stem cell transplantation.

OBJECTIVE: Recent studies suggest that primitive bone marrow-derived cells contribute to regeneration of many tissues, including muscle, endothelium, myocardium, neural tissues, liver, and skin. Conversely, primitive cells resident in muscle and other tissues have been reported to reconstitute hematopoiesis. We investigated the contribution of cells with a primitive hematopoietic phenotype to human epidermal skin formation in recipients of allogeneic mobilized peripheral blood hematopoietic stem cell (HSC) transplantation. PATIENTS AND METHODS: Our study population included female patients who had received granulocyte colony-stimulating factor mobilized peripheral blood HSC transplants from male donors for a variety of benign and malignant hematologic disorders at least 6 months before study entry, with a history of skin graft-vs-host disease. Epidermal skin cells (keratinocytes) obtained from punch biopsies of the skin were cultured under conditions specific for growth and expansion of homogenous populations of keratinocytes from keratinocyte stem cells. After multiple passages, DNA was extracted from cultured cells and evaluated by two different polymerase chain reaction (PCR) method for detection of Y chromosome specific sequences. RESULTS: Neither sensitive PCR-based technique revealed the presence of male donor-derived keratinocyte stem cells in keratinocytes cultured from skin biopsies of female allogeneic transplantation recipients. CONCLUSIONS: We could not confirm the contribution of donor mobilized peripheral blood hematopoietic stem cells to keratinocyte stem cell populations after HSC transplantation. These results cannot explain the presence of donor-derived cells with keratinocyte phenotypic markers in tissue sections of HSC transplant recipients.