Necrotizing sialometaplasia masquerading as residual cancer of the lip.

Necrotizing sialometaplasia is a benign disorder that histologically can mimic carcinoma. It is thought to develop as a result of ischemia or adjacent tissue injury. A patient is described who underwent a Mohs' micrographical fresh-tissue excision of one-third of the upper lip for basal cell carcinoma. By the time she was ready for reconstruction, a marked eczematous reaction developed to a polymyxin neomycin preparation (Neosporin ointment) at the wound edges. Reexcision of the wound margins before a flap reconstruction revealed necrotizing sialometaplasia on histopathological examination. This incidental finding fortunately was not mistaken for residual tumor. To prevent over-diagnosis and over-treatment of presumed malignancies, an awareness of necrotizing sialometaplasia is essential for all surgeons operating on mucosal surfaces in the head and neck.

Stomatal Limitation to Carbon Gain in Paphiopedilum sp. (Orchidaceae) and Its Reversal by Blue Light.

Leaves from Paphiopedilum sp. (Orchidaceae) having achlorophyllous stomata, show reduced levels of stomatal conductance when irradiated with red light, as compared with either the related, chlorophyllous genus Phragmipedium or with their response to blue light. These reduced levels of stomatal conductance, and the failure of isolated Paphiopedilum stomata to open under red irradiation indicates that the small stomatal response measured in the intact leaf under red light is indirect.The overall low levels of stomatal conductance observed in Paphiopedilum leaves under most growing conditions and their capacity to increase stomatal conductance in response to blue light suggested that growth and carbon gain in Paphiopedilum could be enhanced in a blue light-enriched environment. To test that hypothesis, plants of Paphiopedilum acmodontum were grown in controlled growth chambers under daylight fluorescent light, with or without blue light supplementation. Total photosynthetic photon flux density was kept constant in both conditions. Blue light enrichment resulted in significantly higher growth rates-of up to 77%-over a 3 to 4 week growing period, with all evidence indicating that the blue light effect was a stomatal response. Manipulations of stomatal properties aimed at long-term carbon gains could have agronomic applications.