Cell and tissue interactions of Treponema pallidum in primary and secondary syphilitic skin lesions: an ultrastructural study of serial sections.

There are limited reports on the ultrastructure of syphilis skin lesions. The aim of this study has been to perform an electron microscopic investigation of the morphology and the tissue distribution of treponemes in primary and secondary cutaneous lesions. Three cases of primary syphilitic chancre and one case of secondary syphilis were included. Prominent epidermal abnormalities in the primary chancre and a perivascular inflammatory infiltrate in the secondary lesion were found by light microscopy. Ultrastructurally, spirochetes were located mainly in the blood vessel walls and dermal tissue of the chancre lesions. In the secondary syphilis case, spirochetes were more abundant between epidermal keratinocytes. Most of them adjusted to the intercellular spaces. Occasionally, the electron microscopy images were highly suggestive of an intracellular location. Both the ultrastructural and immunohistochemical examination of the primary and secondary syphilis lesions showed a paradoxical distribution of the causative microorganisms compared to the light microscopic changes. In addition, the ultrastructural findings strongly suggest that Treponema pallidum subspecies pallidum invades tissues, not only through an intercellular, but also through a transcellular pathway.

Custom 3D-printed applicators for high dose-rate brachytherapy in skin cancer.

PURPOSE: This paper describes the protocol for the development of 3D-printed custom applicators in treating skin carcinoma, the evaluation of the materials used, and the methods for segmentation and rendering of the applicators. MATERIAL AND METHODS: The segmentation and rendering process for the applicator had six phases: (i) determination of the volume of the lesion using a computed tomography (CT) scan; (ii) delineation of the patient surface, using the same CT images; (iii) creation of the applicator in the planner and segmentation of the mold; (iv) preliminary dosimetry and establishment of the route of the catheter from the brachytherapy unit; (v) creation of the 3D applicator using specialized software; and (vi) applicator printing. Following this process, the patient returned for a second CT to undergo the definitive dosimetry with the applicator in place. Radiation therapy was then administered. RESULTS: We made a total of 16 applicators. Only three applicators had to be remade, two due to an error in the infill and the other due to incorrect catheter geometry. In all cases, correct coverage of the planning target volume was achieved with the prescribed isodose. CONCLUSIONS: The creation of custom molds in plesiotherapy for skin cancer with 3D printing is feasible. Compared to manual methods, 3D printing increases precision in applicator geometry and optimization of the dosimetry.

Allergic contact dermatitis from transdermal buprenorphine.

BACKGROUND: Buprenorphine is a low-molecular-weight, lipophilic, opioid analgesic. The transdermal delivery system (TDS) containing it has skin irritation potential, but at least two cases of contact allergy to the active principal have been described previously. OBJECTIVE: To confirm allergic contact dermatitis from transdermal buprenorphine (TDB) in five older patients suffering from chronic pain and who developed persistent, pruritic erythematous plaques at the contact sites, with two of them also presenting with a generalized skin eruption. METHODS: Besides the baseline patch test series, all five patients were tested with the TDB, four of whom were also tested with the placebo transdermal delivery system as provided by the manufacturer; one patient was also tested with other preparations containing buprenorphine. RESULTS: All reacted to the TDB containing the active principal, the placebo being negative in the four patients tested. The patient tested with the other buprenorphine preparations did react positively to them as well. Tests with TDB in 28 healthy controls were negative. CONCLUSION: We report five cases of delayed hypersensitivity reactions to a TDS containing buprenorphine. Such adverse reactions might be under-reported. A fentanyl-containing TDS is a good alternative in these cases.