Susceptibility to effects of UVB radiation on induction of contact hypersensitivity as a risk factor for skin cancer in humans.

Normal, healthy human volunteers and patients with proved history of non-melanoma skin cancer have been tested for their capacity to develop contact hypersensitivity to dinitrochlorobenzene (DNCB) following exposure of buttock skin to acute, low-dose ultraviolet B (UVB) radiation. Using a radiation protocol that achieves virtually complete depletion of normal-appearing Langerhans cells from irradiated skin, it was learned that approximately 60% of healthy volunteers developed vigorous contact hypersensitivity (CH) when 2000 micrograms DNCB was painted on the irradiated site. These individuals were designated UVB-resistant, and were distinguished from other individuals, designated UVB-susceptible, who failed to develop contact hypersensitivity following an identical treatment protocol. It was then discovered that virtually all (92%) skin cancer patients exposed to UVB and DNCB failed to develop CH, i.e., were UVB-susceptible. In subsequent experiments, epicutaneous application of 2000 micrograms DNCB to unirradiated skin of UVB-susceptible individuals revealed a further distinction between normal persons and skin cancer patients. Approximately 45% of the latter (and none of the former) remained unresponsive (failed to develop contact hypersensitivity following this second attempt at sensitization), implying that they had been rendered immunologically tolerant. These tolerant individuals responded normally to the unrelated hapten, diphencyprone. We conclude that human beings resemble inbred strains of laboratory mice in that some individuals are UVB-susceptible, whereas others are UVB-resistant. Because the incidence of UVB-susceptibility was significantly higher in skin cancer patients, and as specific unresponsiveness could be demonstrated only in these patients, we propose that UVB-susceptibility, as we define it in this hapten system, may be a risk factor for the development of skin cancer.

[Intussusception in disseminated peritoneal leiomyomatosis]. / Intussusceptie bij leiomyomatosis peritonealis disseminata.

A 28-year-old woman presented with intussusception. At laparotomy the peritoneal cavity was found to contain many nodules of various sizes, fitting the diagnosis of 'leiomyomatosis peritonealis disseminata'. A leiomyomatous tumour that caused the intussusception was also found.

An ultraviolet B radiation protocol for complete depletion of human epidermal Langerhans cells.

We report an ultraviolet B (UVB) protocol that achieves essentially complete depletion of Langerhans cells (LC) from human skin, while leaving the skin clinically intact. Sixteen human volunteers of skin types II and III were exposed to 144 mJ/cm2 of UVB each day for 4 successive days, on a 2-cm-diameter circle of buttock skin. In each case the irradiated skin showed redness and mild edema but no vesiculation or ulceration. One hour after the last exposure a 4-mm punch biopsy was taken from the center of the irradiated site. The epidermal sheet from each sample was separated and exposed to CD-1 antibody (12 samples) or HLA-DR antibody (4 samples) and the density of LC was assessed by immunofluorescence light microscopy. In each case the epidermal LC population was severely depleted to less than 20 cells/mm2, from a baseline of approximately 565 cells/mm2, and in many cases no morphologically normal LC remained. This simple protocol thus provides intact human skin completely depleted of LC. Such skin will provide an appropriate model for the in vivo study of the immune function in human skin deprived of its epidermal antigen-presenting capacity.

Needle-knife sphincterotomy as a precut procedure: a retrospective evaluation of efficacy and complications.

BACKGROUND AND STUDY AIMS: Precut sphincterotomy remains a controversial means of gaining biliary access during endoscopic retrograde cholangiopancreatography (ERCP). This report is a retrospective evaluation of the use of needle-knife sphincterotomy as a precut procedure to achieve biliary access during ERCP. PATIENTS AND METHODS: From November 1992 to August 1993, a total of 1071 ERCPs were performed at our institution. During this time, precut sphincterotomy was carried out in 180 patients, with complete follow-up obtained in 178 patients. The follow-up concentrated on the efficacy of the procedure and short-term complications. RESULTS: Cannulation of the common bile duct was achieved immediately after precut sphincterotomy in 88% of the patients, and during a second ERCP in an additional 11% of patients (total success rate 99%). There were no precut-related deaths. The complication rate of precut sphincterotomy was 21 in 178 (12%). Complications included bleeding in ten patients (5.5%), perforation in four patients (3%), pancreatitis in one patient (0.5%), and fever of unknown origin in six (3%) patients. All complications were managed conservatively. CONCLUSIONS: Precut sphincterotomy is a safe and highly effective method of gaining biliary access in patients in whom deep cannulation proves difficult or impossible and biliary access is considered essential.