Urinary excretion of 3-methylhistidine and creatine in carriers of Duchenne muscular dystrophy.

The mean molar ratio (0.0171) of 3-methylhistidine to creatinine in 24-h urine samples from carriers of Duchenne muscular dystrophy did not differ significantly from that of controls. The creatine/creatinine ratio was also normal.     

Mohs micrographic surgery: established uses and emerging trends

Mohs micrographic surgery is a surgical technique that seeks to ensure the clearance of cutaneous tumors while maximizing normal tissue conservation. This is accomplished through the sequential removal of thin layers of tissue in which the entire peripheral and deep margins are examined for residual tumor. This approach appears to be superior to conventional surgical excision in the treatment of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), the two most common cancers of the skin. Its efficacy in treating BCC and SCC has led clinicians to explore the role of Mohs micrographic surgery in the management of less common cutaneous neoplasms, such as melanoma, Merkel cell carcinoma, dermatofibrosarcoma protuberans, extramammary Paget's disease, and microcystic adnexal carcinoma.     

Structural basis for epibatidine selectivity at desensitized nicotinic receptors

The agonist binding sites of the fetal muscle nicotinic acetylcholine receptor are formed at the interfaces of alpha-subunits and neighboring gamma- and delta-subunits. When the receptor is in the nonconducting desensitized state, the alpha-gamma site binds the agonist epibatidine 200-fold more tightly than does the alpha-delta site. To determine the structural basis for this selectivity, we constructed gamma/delta-subunit chimeras, coexpressed them with complementary wild-type subunits in HEK 293 cells, and determined epibatidine affinity of the resulting complexes. The results reveal three determinants of epibatidine selectivity: gamma104-117/delta106-delta119, gamma164-171/delta166-177, and gammaPro190/deltaAla196. Point mutations reveal that three sequence differences within the gamma104-117/delta106-delta119 region are determinants of epibatidine selectivity: gammaLys104/deltaTyr106, gammaSer111/deltaTyr113, and gammaTyr117/deltaTyr119. In the delta-subunit, simultaneous mutation of these residues to their gamma equivalent produces high affinity, gamma-like epibatidine binding. However, converting gamma to delta affinity requires replacement of the gamma104-117 segment with delta sequence, suggesting interplay of residues in this region. The structural basis for epibatidine selectivity is explained by computational docking of epibatidine to a homology model of the alpha-gamma binding site.     

Identification of degradome components associated with prostate cancer progression by expression analysis of human prostatic tissues

Extracellular proteases of the matrix metalloproteinase (MMP) and serine protease families participate in many aspects of tumour growth and metastasis. Using quantitative real-time RT-PCR analysis, we have undertaken a comprehensive survey of the expression of these enzymes and of their natural inhibitors in 44 cases of human prostate cancer and 23 benign prostate specimens. We found increased expression of MMP10, 15, 24, 25 and 26, urokinase plasminogen activator-receptor (uPAR) and plasminogen activator inhibitor-1 (PAI1), and the newly characterised serine proteases hepsin and matriptase-1 (MTSP1) in malignant tissue compared to benign prostate tissue. In contrast, there was significantly decreased expression of MMP2 and MMP23, maspin, and the protease inhibitors tissue inhibitor of metalloproteinase 3 (TIMP3), TIMP4 and RECK (reversion-inducing cysteine-rich protein with Kazal motifs) in the cancer specimens. The expression of MMP15 and MMP26 correlated positively with Gleason score, whereas TIMP3, TIMP4 and RECK expression correlated negatively with Gleason score. The cellular localisation of the expression of the deregulated genes was evaluated using primary malignant epithelial and stromal cell cultures derived from radical prostatectomy specimens. MMP10 and 25, hepsin, MTSP1 and maspin showed predominantly epithelial expression, whereas TIMP 3 and 4, RECK, MMP2 and 23, uPAR and PAI1 were produced primarily by stromal cells. These data provide the first comprehensive and quantitative analysis of the expression and localisation of MMPs and their inhibitors in human prostate cancer, leading to the identification of several genes involved in proteolysis as potential prognostic indicators, in particular hepsin, MTSP1, MMP26, PAI1, uPAR, MMP15, TIMP3, TIMP4, maspin and RECK.