Reconstruction of soft-tissue defects using serratus anterior adipofascial free flap

The serratus anterior muscle has been suggested as a versatile and reliable flap for reconstruction of head and neck and extremity injuries. The adipofascial layer overlying the serratus anterior muscle is the anatomic layer, which is supplied by the same branch of thoracodorsal artery. Even though great progress has occurred in the prevention of postoperative adhesion of extremity injuries, the problem has not been completely solved and is still of special importance in complex injuries. Between March of 1995 and February of 1996, seven patients underwent reconstructive operation as a result of soft-tissue defects of the upper or lower extremities or the scalp. We transferred free adipofascial tissue overlying the serratus anterior muscle in three patients and both serratus anterior muscle and adipofascial tissue in four patients. A free adipofascial flap overlying serratus anterior muscle was transferred when a gliding surface was required, owing to the exposure of tendons and neurovascular structures. The average duration from operation to follow-up examination was 8 months (from 4 to 16 months). The results of the operations were satisfactory in functional and cosmetic aspects. This kind of flap was very effective in reconstruction of soft-tissue defects and gliding surfaces for these reasons: easy dissection, the capability of obtaining a long vascular pedicle, large-sized flap, composite flap including muscle or rib, and the fact that there was no serious functional or cosmetic deficit at the donor site.     

Investigation of extended-spectrum beta-lactamases produced by clinical isolates of Klebsiella pneumoniae and Escherichia coli in Korea

AIMS: Isolates obtained from various regions in Korea in 2002 were identified and their susceptibility to extended-spectrum cephalosporins, monobactams and/or cephamycins was studied along with any production of extended-spectrum beta-lactamases (ESBLs). METHODS AND RESULTS: Bacteria identified by the conventional techniques and Vitek GNI card were Klebsiella pneumoniae and Escherichia coli. Using disk diffusion and double-disk synergy tests, we found that 39.2% of strains produced ESBLs. About 52% of isolates transferred resistance to ceftazidime by conjugation. Banding patterns of PCR amplification with the designed primers showed that 837- and 259-bp fragments specific to bla(TEM) genes were amplified in 63.3% of strains. 929- and 231-bp fragments (bla(SHV)), 847- and 520-bp fragments (bla(CMY)), 597- and 858-bp fragments (bla(CTX-M)) were amplified in 61.5, 17.3 and 7.7% of strains respectively. About 51.9% of strains contained more than two types of beta-lactamase genes. Especially, one strain contained bla(TEM), bla(CMY) and bla(CTX-M) genes. SIGNIFICANCE: Resistance mechanisms to beta-lactams, comprising mostly ESBL production, lead to the resistance against even recently developed beta-lactams in enterobacteria, which is now a serious threat to antibiotic therapy. The high prevalence of bla(CMY) genes and multidrug-resistant genes may also make therapeutic failure and lack of eradiation of these strains by extended-spectrum cephalosporins or cephamycins.     

Increased numbers of B-1 cells and enhanced responses against TI-2 antigen in mice lacking APS, an adaptor molecule containing PH and SH2 domains

APS (adaptor molecule containing PH and SH2 domains) is an intracellular adaptor protein that forms an adaptor family along with Lnk and SH2-B. While experiments using cultured cell lines have demonstrated that APS is phosphorylated in response to various stimuli, its in vivo functions remain unclear. We attempted to determine the physiological roles of APS by generating APS-deficient (APS(-/-)) mice. APS(-/-) mice were viable and fertile and showed no abnormalities or growth retardation. Immunologically, APS(-/-) mice showed normal development and distribution of lymphocytes and myeloid cells, except for increased numbers of B-1 cells in the peritoneal cavity. APS(-/-) mice exhibited an enhanced humoral immune response against trinitrophenol-Ficoll, a thymus-independent type 2 antigen, while APS(-/-) B-2 cells exhibited normal proliferative responses and tyrosine phosphorylation of intracellular proteins upon B-cell receptor (BCR) cross-linking. APS colocalized with filamentous actin (F-actin) accumulated during the capping of BCRs in APS-transgenic B cells. After BCR stimulation, F-actin contents were lower in APS(-/-) B-1 cells than in wild-type B-1 cells. Our results indicate that APS might have a novel regulatory role in actin reorganization and control of B-1 cell compartment size.     

Selective expansion of the newly evolved genomic variants of retrotransposon 1731 in the Drosophila genomes

The structural variants of the regulatory and coding regions of the LTR-retrotransposon 1731 are described. Two classes of genomic copies of retrotransposon 1731, with and without frameshifting strategy to express Gag and Pol proteins, were earlier revealed in the D. melanogaster genome. Copies without frameshifting are shown to be evolved from an ancient variant with frameshifting and are widespread in the genomes of the melanogaster complex species. Position of a rare codon responsible for ribosome pausing and efficient frameshifting is identified. Two structural variants of 1731 LTRs were detected in the melanogaster complex species: the predominant structural variant A1A2 of 1731 LTR in the D. melanogaster, D. simulans, and D. sechellia genomes contains duplicated and diverged copies of 28 bp in the U3 region, whereas A1 variant lacking this duplication is expanded in the D. mauritiana genome. Selective expansion of the A1A2 variant was detected in the independently established D. melanogaster cell cultures. A1A2 variant is expressed in embryos, cell culture, and testes, whereas A1 is expressed only in testes of D. melanogaster. Relief of expression of the A1A2 but not A1 variant in the ovaries as a result of mutation in the RNA interference (RNAi) spn-E gene is shown. Thus, expansion of the recently evolved genomic variants of the LTR retrotransposon 1731 possessing a new translation strategy, duplication in the U3 region, and extended profile of expression is revealed.     

Phospholipase C-delta1 rescues intracellular Ca2+ overload in ischemic heart and hypoxic neonatal cardiomyocytes

Ischemia and simulated ischemic conditions cause intracellular Ca2+ overload in the myocardium. The relationship between ischemia injury and Ca2+ overload has not been fully characterized. The aim of the present study was to investigate the expression and characteristics of PLC isozymes in myocardial infarction-induced cardiac remodeling and heart failure. In normal rat heart tissue, PLC-delta1 (about 44 ng/mg of heart tissue) was most abundant isozymes compared to PLC-gamma1 (6.8 ng/mg) and PLC-beta1 (0.4 ng/mg). In ischemic heart and hypoxic neonatal cardiomyocytes, PLC-delta1, but not PLC-beta1 and PLC-gamma1, was selectively degraded, a response that could be inhibited by the calpain inhibitor, calpastatin, and by the caspase inhibitor, zVAD-fmk. Overexpression of the PLC-delta1 in hypoxic neonatal cardiomyocytes rescued intracellular Ca2+ overload by ischemic conditions. In the border zone and scar region of infarcted myocardium, and in hypoxic neonatal cardiomyocytes, the selective degradation of PLC-delta1 by the calcium sensitive proteases may play important roles in intracellular Ca2+ regulations under the ischemic conditions. It is suggested that PLC isozyme-changes may contribute to the alterations in calcium homeostasis in myocardial ischemia.     

ANG II signaling in vasa recta pericytes by PKC and reactive oxygen species

ANG II constricts descending vasa recta (DVR) through Ca(2+) signaling in pericytes. We examined the role of PKC DVR pericytes isolated from the rat renal outer medulla. The PKC blocker staurosporine (10 microM) eliminated ANG II (10 nM)-induced vasoconstriction, inhibited pericyte cytoplasmic Ca(2+) concentration ([Ca(2+)](cyt)) elevation, and blocked Mn(2+) influx into the cytoplasm. Activation of PKC by either 1,2-dioctanoyl-sn-glycerol (10 microM) or phorbol 12,13-dibutyrate (PDBu; 1 microM) induced both vasoconstriction and pericyte [Ca(2+)](cyt) elevation. Diltiazem (10 microM) blocked the ability of PDBu to increase pericyte [Ca(2+)](cyt) and enhance Mn(2+) influx. Both ANG II- and PDBu-induced PKC stimulated DVR generation of reactive oxygen species (ROS), measured by oxidation of dihydroethidium (DHE). The effect of ANG II was only significant when ANG II AT(2) receptors were blocked with PD-123319 (10 nM). PDBu augmentation of DHE oxidation was blocked by either TEMPOL (1 mM) or diphenylene iodonium (10 microM). We conclude that ANG II and PKC activation increases DVR pericyte [Ca(2+)](cyt), divalent ion conductance into the cytoplasm, and ROS generation.     

Two enzymes in one; two yeast peroxiredoxins display oxidative stress-dependent switching from a peroxidase to a molecular chaperone function

Although a great deal is known biochemically about peroxiredoxins (Prxs), little is known about their real physiological function. We show here that two cytosolic yeast Prxs, cPrxI and II, which display diversity in structure and apparent molecular weights (MW), can act alternatively as peroxidases and molecular chaperones. The peroxidase function predominates in the lower MW forms, whereas the chaperone function predominates in the higher MW complexes. Oxidative stress and heat shock exposure of yeasts causes the protein structures of cPrxI and II to shift from low MW species to high MW complexes. This triggers a peroxidase-to-chaperone functional switch. These in vivo changes are primarily guided by the active peroxidase site residue, Cys(47), which serves as an efficient "H(2)O(2)-sensor" in the cells. The chaperone function of these proteins enhances yeast resistance to heat shock.     

Extracts ofPhellinus gilvus andPhellinus baumii inhibit pulmonary inflammation induced by lipopolysaccharide in rats

Compared to saline-challenged rats, rats exposed to 50 microg intratracheal lipopolysaccharide showed an increase of total white cells (from 0.3 x 10(6) to 2.4 x 10(6)), neutrophils (from 0.09 x 10(6) to 1.8 x 10(6)), the levels of tumor necrosis factor (TNF)-alpha (from 200 pg ml(-1) to 1200 pg ml(-1)), and interleukin (IL)-1beta (from 220 pg ml(-1) to 650 pg ml(-1)) in the bronchial lavage fluid. However, after pretreatment with extracts of Phellinus gilvus and Phellinus baumii, the total white cells, neutrophils, and the level of IL-1beta in lipopolysaccharide-challenged rats were similar to those in saline-challenged rats, except for TNF-alpha. The results indicate that extracts of P. gilvus and P. baumii may be useful in preventing acute pulmonary inflammation in human diseases.     

The modified super-ellipsoid yield criterion for human trabecular bone

Despite the importance of multiaxial failure of trabecular bone in many biomechanical applications, to date no complete multiaxial failure criterion for human trabecular bone has been developed. By using experimentally validated nonlinear high-resolution, micromechanical finite-element models as a surrogate for multiaxial loading experiments, we determined the three-dimensional normal strain yield surface and all combinations of the two-dimensional normal-shear strain yield envelope. High-resolution finite-element models of three human femoral neck trabecular bone specimens obtained through microcomputed tomography were used. In total, 889 multiaxial-loading cases were analyzed, requiring over 41,000 CPU hours on parallel supercomputers. Our results indicated that the multiaxial yield behavior of trabecular bone in strain space was homogeneous across the specimens and nearly isotropic. Analysis of stress-strain curves along each axis in the 3-D normal strain space indicated uncoupled yield behavior whereas substantial coupling was seen for normal-shear loading. A modified super-ellipsoid surface with only four parameters fit the normal strain yield data very well with an arithmetic error +/-SD less than -0.04 +/- 5.1%. Furthermore, the principal strains associated with normal-shear loading showed excellent agreement with the yield surface obtained for normal strain loading (arithmetic error +/- SD < 2.5 +/- 6.5%). We conclude that the four-parameter "Modified Super-Ellipsoid" yield surface presented here describes the multiaxial failure behavior of human femoral neck trabecular bone very well.