Robust explicit estimators using the power-weighted repeated medians.

This paper consists of two parts. The first part of the paper is to propose an explicit robust estimation method for the regression coefficients in simple linear regression based on the power-weighted repeated medians technique that has a tuning constant for dealing with the trade-offs between efficiency and robustness. We then investigate the lower and upper bounds of the finite-sample breakdown point of the proposed method. The second part of the paper is to show that based on the linearization of the cumulative distribution function, the proposed method can be applied to obtain robust parameter estimators for the Weibull and Birnbaum-Saunders distributions that are commonly used in both reliability and survival analysis. Numerical studies demonstrate that the proposed method performs well in a manner that is approximately comparable with the ordinary least squares method, whereas it is far superior in the presence of data contamination that occurs frequently in practice.

Anti-inflammatory and antiproliferative compounds from Sphaeranthus africanus.

BACKGROUND: Sphaeranthus africanus has been used in traditional Vietnamese medicine to treat sore throat, and to relieve pain and swelling. However, the anti-inflammatory activity of this plant had not yet been investigated. Previously, we isolated five carvotacetones (1-5) from this plant that displayed cytotoxicity against several cancer cell lines. PURPOSE: The objective of this study was to isolate further constituents from S. africanus and to investigate the anti-inflammatory activity of all constituents. Furthermore, the anti-proliferative activity of the newly isolated compounds was evaluated. STUDY DESIGN AND METHODS: Compounds were isolated from the upper parts of S. africanus by chromatographic methods. Structures were determined using spectroscopic techniques, like NMR and MS. All nine compounds isolated from S. africanus were evaluated for inhibitory activity against COX-1 and COX-2 isoenzymes in-vitro, COX-2 mRNA expression and influence on NO production. The anti-proliferative activities of newly isolated compounds (6-9) were evaluated by XTT viability assay with four cancer cell lines, namely CCRF-CEM, MDA-MB-231, HCT-116, and U-251 cells. RESULTS: Two diastereomeric carvotacetones (3-angeloyloxy-5-[2″S,3″R-dihydroxy-2″-methyl-butanoyloxy]-7-hydroxycarvotacetone (6) and 3-angeloyloxy-5-[2″R,3″R-dihydroxy-2″-methyl-butanoyloxy]-7-hydroxycarvotacetone (7), asperglaucide (8) and chrysoplenol D (9) were isolated from S. africanus. COX-1 and COX-2 assays of compounds 1-9 revealed that compounds 1 and 2 possess potent and selective COX-2 inhibitory activity with IC50 values of 3.6 and 0.5 µM, respectively. COX-2 gene expression assay showed that some carvotacetones exhibited inhibitory effects on COX-2 gene expression in THP-1 macrophages. Compound 4 is the most active compound inhibiting the synthesis of COX-2 by 55% at 2.06 µM. In the iNOS assay, all seven carvotacetones inhibited NO production in BV2 and RAW cell lines with IC50 values ranging from 0.2 to 2.9 µM. Compound 4 showed potent inhibitory activity with IC50 values of 0.2 µM in both BV2 and RAW cell lines. Molecular docking studies revealed the binding orientations of 1 and 2 in the active sites of COX-2. XTT assay of the newly isolated compounds revealed that the two isomeric carvotacetones (6-7) exhibited considerable anti-proliferative activity against four cancer cell lines (CCRF-CEM, MDA-MB-231, HCT-116, U-251) with IC50 values ranging from 1.23 to 8 µM. CONCLUSION: For the first-time, the diastereomeric carvotacetones (6-7) were isolated as separate compounds, and their anti-proliferative activity was determined. Selective COX-2 inhibitory, COX-2 mRNA expression and NO production inhibitory activities by some of the major constituents of S. africanus supports the traditional medical application of this plant for the treatment of inflammation-related disorders.

[The thoracodorsal artery musculocutaneous perforator flap: anatomic study and clinical significance].

OBJECTIVE: To investigate the feasibility of clinical application of the thoracodorsal artery musculocutaneous perforator flap (TAMPF). METHODS: (1) The morphosis and blood supply of TAP flap on 15 formalized adult cadavers(30 sides) were examined by microsurgery anatomy. (2) An imitative operation of the TAMP flap and latissimus dorsi flap on 1 formalized adult cadavers (2 sides) was conducted. RESULTS: (1) A total of 102 musculocutaneous perforators larger than 0.5 mm were found in 16 specimens(32 sides). 56 perforators (55%) were originated from the medial branch and 46 (45%) originated from the lateral branch. The biggest perforator is (0.82 +/- 0.11) mm (0.68 - 1.08 mm). There was an average of 1.9 perforators (range, 1 - 3 perforators) of the medial branch and an average of 1.8 perforators (range, 1 - 3 perforators) of the lateral branch. Additionally, there were 24 perforators samller than 0.5 mm, and 76 perforators originated from intercostal artery and lumbar artery. (2) Musculocutaneous perforators over 0.5 mm were found only in proximity of the medial and lateral branches within a distance of 8.5 cm (6.4 cm - 9.2 cm) distal to the neurovascular hilus. CONCLUSIONS: With the characteristics of constant position, large caliber, long pedicle, the thoracodorsal artery musculocutaneous perforator was suitable to be musclocutaneous perforator flaps and "fan-shaped" flaps.

[Heel deep tissue defects were repaired by perineal tendofascial flap conjoined with adipofascial flap].

OBJECTIVE: To explore a new method and estimate its outcome to repair deep heel tissue injuries with local tissue flap. METHODS: At lower cnemis, a fat fascial flap combined with perineal tendofascial flap were designed and elevated between the lateral malleolars blank, the largest area is 6 cm x 13 cm, which were transplanted to cover naked calcaneal tendon and calcaneal bone, full-thickness free skin graft or middle-thickness free skin graft were grafted on flap. RESULTS: 6 patients suffered from heel tissue defects had been treated from January 2004 to November 2005. The smallest area was 3.5 cm x 4.0 cm and the largest was 4 cm x 6 cm. All fascial flaps and free skin grafts were successfully survived after operations. All patients were followed up 3-23 months, the operation areas were healed, the functions and configurations were satisfied. CONCLUSIONS: Perineal tendofascial flap conjoined with adipofasical flap and free skin graft are used to repair heel deep tissue defects, which is a handy, dependable way for repairing of the small tissue defects of the lower third of leg and heel.

[Nasal reconstruction with the modified expanded forehead skin flap].

OBJECTIVE: To investigate the effect of the modified expanded forehead skin flap in nasal reconstruction. METHODS: According to flap design, the frontal arteries that were not selected as the pedicle were ligated in order to enhance expansion and delay effects. Besides the middle forehead skin flap for nasal reconstruction, the expanded transversal forehead flap was employed with its donor site sutured directly, resulting in inconspicuous scar. This method was used for 11 cases of nasal reconstruction. RESULTS: All the flaps survived. Postoperative follow up for 6 months to 8 years and 4 months showed satisfactory results with good appearance and function. CONCLUSIONS: The method of modulating the blood supply to the flap and selecting the upper area of the forehead for the flap is an effective modification for nasal reconstruction.