Rectal duplication cyst in adults treated with transanal endoscopic microsurgery.

Rectal duplication cyst is a rare entity that accounts for approximately 4% of all alimentary tract duplications. To the best of our knowledge, the presented cases are the first reports in the English literature of rectal duplication cyst resection by transanal endoscopic microsurgery. We present two patients; both are 41-year-old women with a palpable rectal mass. Workup revealed a submucosal posterior mass that was then resected by transanal endoscopic microsurgery. The pathology report described cystic lesions with squamous and columnar epithelium and segments of smooth muscle. These findings were compatible with rectal duplication cyst. Our limited experience showed good results with minimal morbidity and mortality for resection of rectal duplication cysts of limited size with no evidence of malignancy.

What are melanocytes really doing all day long...?

Everyone knows and seems to agree that melanocytes are there to generate melanin - an intriguing, but underestimated multipurpose molecule that is capable of doing far more than providing pigment and UV protection to skin (1). What about the cell that generates melanin, then? Is this dendritic, neural crest-derived cell still serving useful (or even important) functions when no-one looks at the pigmentation of our skin and its appendages and when there is essentially no UV exposure? In other words, what do epidermal and hair follicle melanocytes do in their spare time - at night, under your bedcover? How much of the full portfolio of physiological melanocyte functions in mammalian skin has really been elucidated already? Does the presence or absence of melanocytes matter for normal epidermal and/or hair follicle functions (beyond pigmentation and UV protection), and for skin immune responses? Do melanocytes even deserve as much credit for UV protection as conventional wisdom attributes to them? In which interactions do these promiscuous cells engage with their immediate epithelial environment and who is controlling whom? What lessons might be distilled from looking at lower vertebrate melanophores and at extracutaneous melanocytes in the endeavour to reveal the 'secret identity' of melanocytes? The current Controversies feature explores these far too infrequently posed, biologically and clinically important questions. Complementing a companion viewpoint essay on malignant melanocytes (2), this critical re-examination of melanocyte biology provides a cornucopia of old, but under-appreciated concepts and novel ideas on the slowly emerging complexity of physiological melanocyte functions, and delineates important, thought-provoking questions that remain to be definitively answered by future research.

Novel mutations in DSG1 causing striate palmoplantar keratoderma.

BACKGROUND: Striate palmoplantar keratoderma (SPPK) has been shown to be caused by mutations in at least three genes: DSG1, DSP and KRT1. METHODS: Three families with nine affected members were assessed using a candidate gene-based screening approach. RESULTS: In all three families, new heterozygous mutations were found in DSG1. CONCLUSION: Direct sequencing of cDNA derived from affected skin in one patient failed to reveal a pathogenic mutation, suggesting that SPPK results from haploinsufficiency for DSG1.

Pure sinusoidal photo-modulation using an acousto-optic modulator.

We use an arbitrary waveform generator to generate a clean sinusoidal modulation from the otherwise nonlinear acousto-optic modulator (AOM). A closed loop optimization script is applied to reduce high order harmonic distortion to less than 0.05% in a high AOM diffraction efficiency regime. This low level of distortion allows us to measure the nonlinear response to photoexcitation of many materials. We demonstrate this technique in a pump-probe experiment to measure the Nonlinear Photo-Modulated Reflectivity (NPMR) of surfaces. NPMR served us as the basis for developing super-resolution microscopy for non-fluorescence samples (label-free) as well as a tool in studying the ultrafast nonlinear response of photo-excited plasmonic nano-structures. Our methodology could be applied to other imaging systems in which measuring nonlinearity is desirable, such as fluorescence and photoacoustic microscopy.

RASA1 mutations may cause hereditary capillary malformations without arteriovenous malformations.

BACKGROUND: Capillary malformation (CM), a common vascular abnormality, is often present among family members. Recently a rare form of hereditary vascular malformation termed capillary malformation-arteriovenous malformation (CM-AVM) was shown to be caused by heterozygous mutations in RASA1, encoding RAS p21 protein activator 1. CM-AVM is characterized by multiple, small CMs associated with either AVM or arteriovenous fistula (AVF) in affected individuals or at least one of their family members. OBJECTIVES: The purpose of the study was to find out whether CMs in the absence of AVM/AVF are associated with RASA1 mutations. PATIENTS/METHODS: We assessed three families comprising 14 affected individuals with CMs. Linkage to the RASA1 locus was evaluated using microsatellite markers. The RASA1 gene was scrutinized for pathogenic mutations using denaturing high-performance liquid chromatography screening and direct sequencing. RESULTS: AVM/AVF was identified in one of three affected families. CM without AVM/AVF was found to map in one large kindred to the RASA1 locus. Direct sequencing revealed novel heterozygous mutations segregating with CM in all three families. The mutations are predicted to result in premature termination of translation and RASA1 haplo-insufficiency. CONCLUSIONS: We have demonstrated that the spectrum of clinical manifestations due to mutations in RASA1 is wider than previously thought and also includes typical CMs not associated with AVM/AVF.