Precise intraoperative 60 degrees Skin Z-plasty.

The primary objective of this tip is to assist foot and ankle surgeons in performing a precise 60 degrees lengthening Z-plasty in the operating room without the use of a template or protractor. A ruler and basic trigonometric principles are applied to the line of contracture to obtain consistent and reliable results.

Prostate specific antigen as a clinical biomarker for prostate cancer: what's the take home message?

Prostate specific antigen (PSA) continues to be challenged as a legitimate clinical biomarker in early detection of prostate cancer due to lack of specificity for malignant transformation. Skepticism surrounding the utility of serum PSA as a clinical marker is not new and many questioned its initial use in widespread prostate cancer screening due to non-specific expression and low predictive value for cancer detection. Despite these initial concerns, serum PSA measurement along with digital rectal examination (DRE) is currently the accepted practice for prostate cancer screening in the United States with hundreds of thousands of men undergoing serum PSA measurement annually. In contrast to its role for early detection, serum PSA measurement as a surrogate for prostate cancer recurrence (biochemical failure) following curative intent therapy has consummate clinical utility in post-treatment surveillance. As thousands of men each year are aggressively treated for potentially curable prostate cancer, development of simple and effective diagnostic tools for detecting treatment failures should be an important area of biomedical and clinical investigation. We have constructed and tested a home-based prostate cancer surveillance device for use by patients to detect PSA from blood obtained by finger stick. Our initial results suggest that home based PSA testing is feasible and may have clinical utility in management of men treated for prostate cancer.

Antibiotic cement-coated plates for management of infected fractures.

Deep infection in the presence of an implant after open reduction and internal fixation is usually treated with removal of the implant, serial débridement procedures, lavage, intravenously administered antibiotics, and occasionally, placement of antibiotic-impregnated beads. If infection occurs during the early stages of bone healing, fracture stabilization might be compromised after implant removal. Osteomyelitis, unstable owing to a bone deficit or fracture, was treated with an antibiotic cement-coated (tobramycin and vancomycin) plate. The goal was successful eradication of infection with the patient remaining infection-free for 1 year. Four patients were treated with antibiotic-coated plates for osteomyelitis and all have achieved successful union, clinically free of signs of infection for more than 1 year. One patient experienced a prominent and painful plate, necessitating removal. Based on our experience, early aggressive débridement coupled with broad-spectrum antibiotic cement-coated plate insertion, provides fracture stability and helps eradicate the infection with 1 surgical procedure.

Practical aspects of foot and ankle arthroscopy.

Arthroscopy of the foot and ankle, although sometimes technically challenging, is a useful tool for the foot and ankle surgeon. Burman in 1931 was the first to attempt arthoscopy of the ankle joint and surmised that it was not a suitable joint for arthroscopy because of its narrow intra-articular space. With the development of smaller-diameter arthroscopes and improvements in joint distraction techniques, Watanabe was the first to present a series of 28 ankle arthroscopes in 1972. At present, arthroscopy is used not only to evaluate and treat intra-articular abnormalities but also for endoscopic and tendoscopic procedures.

The orphan nuclear receptor LRH-1 activates the ABCG5/ABCG8 intergenic promoter.

The ATP binding cassette (ABC) half-transporters ABCG5 and ABCG8 facilitate biliary and intestinal removal of neutral sterols. Here, we identify a binding site for the orphan nuclear receptor liver receptor homolog-1 (LRH-1) at nt 134-142 of the ABCG5/ABCG8 intergenic region necessary for the activity of both the ABCG5 and ABCG8 promoters. Mutating this LRH-1 binding site reduced promoter activity of the human ABCG5/ABCG8 intergenic region more than 7-fold in HepG2 and Caco2 cells. Electrophoretic mobility shift assays with HepG2 nuclear extracts demonstrated specific binding of LRH-1 to the LRH-1 binding motif in the human ABCG5/ABCG8 intergenic region. LRH-1 overexpression increased promoter activity up to 1.6-fold and 3-fold in Caco2 and 293 cells, respectively. Finally, deoxycholic acid repressed the ABCG5 and ABCG8 promoters, consistent with bile acid regulation via the farnesoid X receptor-small heterodimeric partner-LRH-1 pathway. These results demonstrate that LRH-1 is a positive transcription factor for ABCG5 and ABCG8 and, in conjunction with studies on LRH-1 activation of other promoters, identify LRH-1 as a "master regulator" for genes involved in sterol and bile acid secretion from liver and intestine.

Comparative genome analysis of potential regulatory elements in the ABCG5-ABCG8 gene cluster.

The excretion of sterols from the liver and intestine is regulated by the ABCG5 and ABCG8 transporters. To identify potential regulatory elements, 152 kb of the human ABCG5-ABCG8 gene cluster was sequenced and comparative genome analysis was performed. The two genes are oriented in a head-to-head configuration and are separated by a 374-bp intergenic region, which is highly conserved among several species. Using a reporter construct, the intergenic region was found to act as a bidirectional promoter. A conserved GATA site in the intergenic region was shown by site-directed mutagenesis to act as a repressor for the ABCG5 promoter. The intergenic region was also shown to be partially responsive to treatment by LXR agonists. In summary, several potential regulatory elements were found for the ABCG5 and ABCG8 genes, and the intergenic region was found to act as a bidirectional promoter.

Synthetic amphipathic helical peptides promote lipid efflux from cells by an ABCA1-dependent and an ABCA1-independent pathway.

In order to examine the necessary structural features for a protein to promote lipid efflux by the ABCA1 transporter, synthetic peptides were tested on ABCA1-transfected cells (ABCA1 cells) and on control cells. L-37pA, an l amino acid peptide that contains two class-A amphipathic helices linked by proline, showed a 4-fold increase in cholesterol and phospholipid efflux from ABCA1 cells compared to control cells. The same peptide synthesized with a mixture of l and d amino acids was less effective than L-37pA in solubilizing dimyristoyl phosphatidyl choline vesicles and in effluxing lipids. In contrast, the 37pA peptide synthesized with all d amino acids (D-37pA) was as effective as L-37pA. Unlike apoA-I, L-37pA and D-37pA were also capable, although at a reduced rate, of causing lipid efflux independent of ABCA1 from control cells, Tangier disease cells, and paraformaldehyde fixed ABCA1 cells. The ability of peptides to bind to cells correlated with their lipid affinity. In summary, the amphipathic helix was found to be a key structural motif for peptide-mediated lipid efflux from ABCA1, but there was no stereoselective requirement. In addition, unlike apoA-I, synthetic peptides can also efflux lipid by a passive, energy-independent pathway that does not involve ABCA1 but does depend upon their lipid affinity.