Ben R. Bronstein

Human cutaneous dendritic cells express two glycoproteins T6 and M241 which are biochemically identical to those found on cortical thymocytes.

Monoclonal antibodies anti-T6 and anti-M241 define unique cell populations within different lineages: cortical thymocytes and dendritic cells in the skin. T6 positive cutaneous dendritic cells are located predominantly in the epidermis and belong to the Langerhans/indeterminate lineage, whereas, most of the M241 positive cells are located in the perivascular regions of the dermis. Biochemical analysis of thymocytes and cutaneous dendritic cells was performed in order to determine whether the reactivity of these antibodies with these cell types is due to sharing of antigenic determinants by two unrelated proteins, or whether similar proteins are present on cells of different lineages. Our results indicate that T6 antigens are borne by the same glycoprotein (49K) on cortical thymocytes and Langerhans/indeterminate cells. Similarly, M241 antigens isolated from thymocytes and cutaneous dendritic cells are found on the same glycoprotein (43K).

Follicular mucinosis: A detailed morphologic and immunopathologic study

Two patients with the benign type of follicular mucinosis (FM) are presented. Their clinical features and course were characteristic for this subgroup of FM. Light and electron microscopy, direct immunofluorescence, and immunoperoxidase cell marker studies were undertaken to characterize the nature of the disease process. Light microscopy confirmed the follicular outer root sheath and sebaceous gland epithelial degenerative changes. The infiltrating inflammatory cells were morphologically benign. Electron microscopy detailed the cellular associations in the areas of degenerative change. Disattached keratinocytes were closely apposed to significant numbers of macrophages and Langerhans cells. Direct immunofluorescence studies demonstrated primarily complement (C3) and fibrinogen/fibrin in areas of reticular degeneration. Immunoperoxidase studies revealed large numbers of T cells and macrophages and a striking increase in the number of Langerhans cells in the affected follicular epithelium. The findings suggest that cell-mediated immune mechanisms may play a role in the pathogenesis of this disorder.

Hereditary callosities with blisters: Report of a family and review

A family with calluses of the soles associated with blistering is described. Electron microscopic study of a bulla showed an intraepidermal blister with cytolysis of keratinocytes and clumping of tonofilaments. Review of the literature and our own experience with keratoderma palmaris et plantaris revealed no similar patients with this combination of findings. The appearance of the soles is similar to pachyonychia congenita, but the lack of nail and mucous membrane changes is not consistent with that disorder. Treatment with isotretinoin caused reduction in the size of the calluses but exacerbated the blistering.

Prognosis for polypoidal melanoma is determined by primary tumor thickness

Survival of 23 patients with polypoidal malignant melanomas was compared with an identical number of patients with nonpolypoidal melanomas of similar thickness, stage, and location. Five‐year survivals for the two groups were not significantly different. The dominant prognostic factor leading to the adverse prognosis associated with polypoidal melanomas was the primary tumor thickness (all > 1.70 mm) and not the polypoidal morphologic configuration per se.

Selective vascular coagulation of rabbit colon using a flashlamp-excited dye laser operating at 577 nanometers

Previous studies have demonstrated that brief pulses of selectively absorbed optical radiation can be used to confine thermal injury to pigmented targets within tissues. We performed studies in rabbits to assess the usefulness of this technique for selectively coagulating the colonic vasculature. By measuring the optical absorbance of rabbit colon with a spectrophotometer, it was determined that hemoglobin exhibits strong absorption relative to the rabbit colon at a wavelength of 577 nm. Because light must be absorbed to affect tissue, it was hypothesized that laser pulses of this wavelength would selectively damage blood vessels. This hypothesis was tested by examining the effect of 300-microseconds-long 577-nm laser pulses on rabbit colon in vivo. For delivered radiant exposures between 4 and 8 J/cm2, selective coagulation of the colonic vasculature could be produced without damage to the surrounding colon. At greater radiant exposures, vessel hemorrhage was occasionally noted but no transmural thermal injury was produced with delivered radiant exposures as high as 22 J/cm2. This technique may form the basis of a safe and simple treatment of vascular lesions of the colon such as angiodysplasia.

Intermittent hair follicle dystrophy

A new disorder of the hair follicle is described that leads to increased fragility of the shaft. Light microscopic studies of hair follicles revealed disturbances of keratinization in the shafts that are very likely responsible for the breakage. The most consistent change seen by transmission electron microscopy was intercellular edema of the outer root sheath, while scanning electron microscopy of the hair revealed disturbances of the surface and broken ends. Specific biochemical abnormalities of the hair proteins were not found. Possible mechanisms for the disease are discussed. (J Am Acad Dermatol 15:54-60, 1986.)