Effect of UVB 311 nm irradiation on normal human skin

Ultraviolet radiation B (UVB) on the skin induces erythema, inflammation and modifications of the immune system. These changes have been reported after excessive short-term or long-term exposure to broad spectrum UVB. In this study, we examined the effects of local repetitive UVB irradiation of 311 nm wavelength on the skin of seven young volunteers. Skin biopsies were taken before and after UVB irradiation, and we immunohistochemically analyzed the expression of CD1a and HLA-DR antigens of Langerhans cells (LC), the possible infiltration of dermis/epidermis by CD11b macrophages, the modifications or the induction of intercellular adhesion molecule-1 (ICAM-1), E-selectin and vascular cell adhesion molecule-1 (VCAM-1) involved in the binding of leukocytes to the endothelial surface and the development of perivascular infiltrates of LFA-1⁺ mononuclear cells. We also determined the expression of substance P receptors (SPR) using biotinylated substance P (SPB). Exposure of UVB 311 nm induced a drastic reduction of CD1a⁺ cells and a moderate increase of HLA-DR⁺ dendritic cells in the epidermis without infiltration by CD11b macrophages. An increase of the binding of SPB to upper layer epidermal cells was noted in five of seven biopsies. In the dermis, vessel-associated ICAM-1 expression increased and an induction of E-selectin occurred on nearly 20 to 40% of endothelial cells, but VCAM-1 expression remained undetectable. The percentage of LFA-1⁺ cells did not change significantly after irradiation. These observations may be compatible with a selective role of UVB 311 nm on the skin immune response.     

Clinical quiz. Rubinstein-Taybi syndrome (synonyms: broad thumbs and great toes, characteristic facies, and mental retardation -- broad thumb-hallux syndrome).

A 28-year-old mentally retarded, institutionalised woman was referred to us for evaluation of multiple plantar warts and ingrown nails of both great toes. The patient was born to unrelated parents of North African origin and had one brother and three half-brothers, all of whom were healthy. Physical examination revealed short stature, slight obesity, facial abnormalities (Fig. 1), short and broad thumbs and big toes (Figs. 2 and 3). A keloid was found on the right forearm, that had developed after surgical correction of a fracture (Fig. 4). Ill-defined hyperpigmented macules were observed on the trunk. The patient also presented pruritic eczematous lesions of the limbs and the back that had been present for some years and were recurrent despite treatment with emollients and local steroids. Androgenetic-type alopecia of moderate severity was seen on the vertex of the scalp. Past medical history included polydactylism of the feet and clinodactyly of the thumbs (both corrected surgically), respiratory tract infections, Wolf-Parkinson-White syndrome and refractive errors necessitating glasses.     

Structural and Mechanical Repair of Diffuse Damage in Cortical Bone In Vivo

Physiological wear and tear causes bone microdamage at several hierarchical levels, and these have different biological consequences. Bone remodeling is widely held to be the mechanism by which bone microdamage is repaired. However, recent studies showed that unlike typical linear microcracks, small crack damage, the clusters of submicron‐sized matrix cracks also known as diffuse damage (Dif.Dx), does not activate remodeling. Thus, the fate of diffuse damage in vivo is not known. To examine this, we induced selectively Dif.Dx in rat ulnae in vivo by using end‐load ulnar bending creep model. Changes in damage content were assessed by histomorphometry and mechanical testing immediately after loading (ie, acute loaded) or at 14 days after damage induction (ie, survival ulnae). Dif.Dx area was markedly reduced over the 14‐day survival period after loading (p < 0.02). We did not observe any intracortical resorption, and there was no increase in cortical bone area in survival ulnae. The reduction in whole bone stiffness in acute loaded ulnae was restored to baseline levels in survival ulnae (p > 0.6). Microindentation studies showed that Dif.Dx caused a highly localized reduction in elastic modulus in diffuse damage regions of the ulnar cortex. Moduli in these previously damaged bone areas were restored to control values by 14 days after loading. Our current findings indicate that small crack damage in bone can be repaired without bone remodeling, and they suggest that alternative repair mechanisms exist in bone to deal with submicron‐sized matrix cracks. Those mechanisms are currently unknown and further investigations are needed to elucidate the mechanisms by which this direct repair occurs. © 2014 American Society for Bone and Mineral Research     

Regeneration of cutaneous innervation in a human hand allograft

On Sept 23, 1998, a human hand allograft was done in our hospital. We followed up the patients for 24 months to assess the skin structure by immunohistology. Most cutaneous structures (including dermal nerves with their Schwann cells and perineurial fibroblasts) were present immediately after surgery and remained detectable throughout the study; from day 464 onwards, axons became detectable within dermal nerves, and their density increased progressively with time. Merkel cells reappeared in the epidermis 12 months after the operation. The regeneration of cutaneous innervation paralleled the recovery of cutaneous sensitivity.     

No recurrence of posttransplantation Kaposi's sarcoma three years after renal retransplantation

Kaposi's sarcoma (KS) develops in 0.5-5% of organ transplant patients; it usually regresses upon treatment reduction, but this may result in graft loss necessitating return to dialysis and/or retransplantation. Until now posttransplantation KS is considered to recur upon reintroduction of immunosuppressive treatment, a fact that has limited retransplantation of patients with previous KS. We report a patient with posttransplantation KS who received a second renal transplantation after having been off immunosuppressive treatment for 10 years, in whom KS has not recurred more than 3 years after retransplantation. This unique observation suggests that retransplantation of patients with previous posttransplantation KS is possible.     

Melanotrichoblastoma: immunohistochemical study of a variant of pigmented trichoblastoma

Trichoblastomas (TBs) are benign skin tumors recapitulating the differentiation of hair follicles. Several pathologic variants have been described, including the rare pigmented TB. We report a deeply pigmented nodular tumor excised on the scalp of a 32-year-old African woman, which was clinically suggestive of blue nevus or melanoma. Histologically, the tumor presented features of TB, remarkable by virtue of heavy melanin deposits found within and around tumor nests. By immunohistochemistry, abundant dendritic melanocytes with features of hair follicle melanocytes (expression of S100 protein, tyrosinase, and, most importantly, gp100/HMB-45) were found within the tumor masses. By analogy with melanoacanthoma, a tumor consisting of a combined proliferation of epidermal keratinocytes and melanocytes, we called this tumor "melanotrichoblastoma" and view it as a peculiar variant of (pigmented) TB.     

Acyclovir-resistant varicella infection with atypical lesions in a non-HIV leukemic infant

An HIV-negative infant presented with VZV primary infection during the maintenance therapy for megakaryoblastic leukaemia. The lesions were initially vesicular and necrotic but became verrucous and hyperkeratotic. A clinical resistance to acyclovir was suspected and confirmed by histologic and virologic studies. The patient was successfully treated by foscarnet. CONCLUSION: resistance of VZV to acyclovir may occur after a short treatment in a non-AIDS patient.     

Eccrine porocarcinoma. Ultrastructural and immunological study

The histological, electron microscopic, and immunological findings in a case of eccrine porocarcinoma are described. The tumors were verrucous, wart-like lesions and nodules which ulcerated secondarily. They were located on the leg. The patient died in a few months from dissemination of the disease. The tumor examined was epidermotropic and mainly composed of a clear cell proliferation. Ultrastructurally, the cells showed large, nucleolated nuclei, numerous mitochondria, dilated endoplasmic reticulum, single desmosomal plaques, sparse tonofibrils in the perinuclear region, multivesicular dense bodies, and interdigitating cytomembranes. A few dark cells were present. No Langerhans cells, indeterminate dendritic cells or melanocytes were observed. The tumor cells were labeled with KL 1 monoclonal antikeratin antibody. The secretory cells of uninvolved eccrine sweat glands in the close vicinity of the tumor and in the perilesional skin were strongly labeled with D 47 monoclonal antibody reacting with the secretory cells of human eccrine sweat gland, whereas the tumor cells remained unlabeled. Our study results showed that the origin of this tumor was not the secretory portion of the gland but rather its excretory portion.