Persistent pediatric contact leukoderma after exposure to butterfly electrocardiogram back pad: a report of three cases.

Contact leukoderma or chemical leukoderma refers to hypopigmentation related to the application of chemical compounds to the skin. Hypopigmentation can occur with or without preceding inflammatory eczematous changes. We present three cases of contact leukoderma associated with exposure to a new type of electrocardiogram electrode back pad.

Mucin-producing Malignant Tumor of Lower Eyelid Presenting in a 14-year-old Patient.

Malignancies of the ocular adnexa are rare, aggressive tumors with significant potential for local recurrence and metastases. Although basal cell carcinoma remains the most common malignancy of the eyelid, encompassing more than 90 percent of all periocular cancers, several other malignant neoplasms have been reported. Malignant ocular adnexal neoplasms are most commonly of sweat gland origin and include hidradenocarcinoma, mucinous eccrine adenocarcinoma, and apocrine adenocarcinoma of the glands of Moll. The different ocular adnexal adenocarcinomas share many of the same characteristics with regard to incidence, primary location, and rates of recurrence and metastases. As a result, these tumors are difficult to distinguish clinically and true diagnosis depends on histological findings. The highest incidence of the reported cases occurred during the sixth decade of life. The head, neck, and trunk are the most frequently reported primary locations. Ocular adnexal adenocarcinomas have a significant rate of metastasis to regional lymph nodes as well as distant sites. Standard treatment of care includes surgical excision of the tumor; however, these malignancies have a tendency to recur locally. The authors present a 14-year-old Caucasian girl with no significant past medical history who presented with a recurrent right lower eyelid tumor. She previously had multiple resections at an outside hospital; however, the margins could not be cleared. The patient was taken to the operating room for Mohs-type resection of the primary site as well as a right parotidectomy with facial nerve preservation and right modified radical neck dissection. The final pathology was consistent with a mucin-producing malignant tumor of ocular adnexa. Due to the great potential for local recurrence and metastases, the prognosis for ocular adnexal adenocarcinoma remains poor even with aggressive surgical management. The use of Mohs surgery for resection has increased as it has been linked to prolonged intervals of metastatic-free disease.

Remyelination in experimentally demyelinated connexin 32 knockout mice.

The aim of this study was to evaluate the role of connexin 32 (Cx 32) during remyelination of the peripheral nervous system, through a local injection of either 0,1% ethidium bromide solution or saline in the sciatic nerve of Cx 32 knockout mice. Euthanasia was performed ranging from 1, 2, 3, 7, 15, 21 to 30 days after injection. Histochemical, immunohistochemical, immunofluorescence and transmission electron microscopical techniques were used to analyze the development of the lesions. Within the sciatic nerves, Schwann cells initially showed signs of intoxication and rejected their sheaths; after seven days, some thin newly formed myelin sheaths with uneven compactness and redundant loops (tomacula) were conspicuous. We concluded that the regeneration of lost myelin sheaths within the PNS followed the pattern already reported for this model in other laboratory species. Therefore, these results suggest that absence of Cx 32 did not interfere with the normal pattern of remyelination in this model in young mice.

Remyelination in experimentally demyelinated connexin 32 KnockOut mice / Remielinização em camundongos KnockOut para conexina 32 desmielinizados experimentalmente

The aim of this study was to evaluate the role of connexin 32 (Cx 32) during remyelination of the peripheral nervous system, through a local injection of either 0,1 percent ethidium bromide solution or saline in the sciatic nerve of Cx 32 knockout mice. Euthanasia was performed ranging from 1, 2, 3, 7, 15, 21 to 30 days after injection. Histochemical, immunohistochemical, immunofluorescence and transmission electron microscopical techniques were used to analyze the development of the lesions. Within the sciatic nerves, Schwann cells initially showed signs of intoxication and rejected their sheaths; after seven days, some thin newly formed myelin sheaths with uneven compactness and redundant loops (tomacula) were conspicuous. We concluded that the regeneration of lost myelin sheaths within the PNS followed the pattern already reported for this model in other laboratory species. Therefore, these results suggest that absence of Cx 32 did not interfere with the normal pattern of remyelination in this model in young mice.

Este estudo visou avaliar o papel da conexina 32 (Cx 32) durante a remielinização no sistema nervoso periférico. Uma injeção local de 0,1 por cento de solução de brometo de etídio foi realizada no nervo ciático de camundongos deletados para a Cx 32, com eutanásia dos animais aos 1, 2, 3, 7, 15, 21 e 30 dias pós-injeção. Avaliações histoquímicas, imunoistoquímicas, por imunofluorescência e por microscopia eletrônica de transmissão foram utilizadas na análise do desenvolvimento das lesões. Nos nervos ciáticos, células de Schwann mostraram inicialmente sinais de intoxicação e rejeitaram suas bainhas. Após sete dias, observaram-se finas bainhas neoformadas, com compactação desigual e alças redundantes (tomácula). Conclui-se que a regeneração de bainhas de mielina perdidas no SNP seguiu o padrão já relatado deste modelo em outras espécies de laboratório. Portanto, estes resultados sugerem que a ausência da Cx 32 não interferiu com o padrão normal de remielinização em camundongos jovens neste modelo.