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101.
102.
M E Gottlieb B Chandrasekhar J J Terz R Sherman 《Plastic and reconstructive surgery》1986,78(6):782-792
The extended deep inferior epigastric flap, described by Taylor et al. in 1983, consists of the lower portion of the rectus abdominis muscle and a superolateral fasciocutaneous extension based on the periumbilical perforators. We have used this flap four times to close large defects of the abdomen, groin, and thigh and twice as a free flap to close wounds of the head and leg. There were no ischemic complications, and there was uncomplicated wound healing in the recipient and in the donor wounds. We recommend this highly versatile and reliable flap as one to be considered early in planning the closure of large wounds. 相似文献
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Chandrasekhar Gurramkonda Ahmad Adnan Thomas Gäbel Heinrich Lünsdorf Anton Ross Satish Kumar Nemani Sathyamangalam Swaminathan Navin Khanna Ursula Rinas 《Microbial cell factories》2009,8(1):13-8
Background
Hepatitis B is a serious global public health concern. Though a safe and efficacious recombinant vaccine is available, its use in several resource-poor countries is limited by cost. We have investigated the production of Hepatitis B virus surface antigen (HBsAg) using the yeast Pichia pastoris GS115 by inserting the HBsAg gene into the alcohol oxidase 1 locus. 相似文献108.
Arjunan P Sax M Brunskill A Chandrasekhar K Nemeria N Zhang S Jordan F Furey W 《The Journal of biological chemistry》2006,281(22):15296-15303
The crystal structure of the E1 component from the Escherichia coli pyruvate dehydrogenase multienzyme complex (PDHc) has been determined with phosphonolactylthiamin diphosphate (PLThDP) in its active site. PLThDP serves as a structural and electrostatic analogue of the natural intermediate alpha-lactylthiamin diphosphate (LThDP), in which the carboxylate from the natural substrate pyruvate is replaced by a phosphonate group. This represents the first example of an experimentally determined, three-dimensional structure of a thiamin diphosphate (ThDP)-dependent enzyme containing a covalently bound, pre-decarboxylation reaction intermediate analogue and should serve as a model for the corresponding intermediates in other ThDP-dependent decarboxylases. Regarding the PDHc-specific reaction, the presence of PLThDP induces large scale conformational changes in the enzyme. In conjunction with the E1-PLThDP and E1-ThDP structures, analysis of a H407A E1-PLThDP variant structure shows that an interaction between His-407 and PLThDP is essential for stabilization of two loop regions in the active site that are otherwise disordered in the absence of intermediate analogue. This ordering completes formation of the active site and creates a new ordered surface likely involved in interactions with the lipoyl domains of E2s within the PDHc complex. The tetrahedral intermediate analogue is tightly held in the active site through direct hydrogen bonds to residues His-407, Tyr-599, and His-640 and reveals a new, enzyme-induced, strain-related feature that appears to aid in the decarboxylation process. This feature is almost certainly present in all ThDP-dependent decarboxylases; thus its inclusion in our understanding of general thiamin catalysis is important. 相似文献
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Beahm DL Oshima A Gaietta GM Hand GM Smock AE Zucker SN Toloue MM Chandrasekhar A Nicholson BJ Sosinsky GE 《The Journal of biological chemistry》2006,281(12):7994-8009
Single site mutations in connexins have provided insights about the influence specific amino acids have on gap junction synthesis, assembly, trafficking, and functionality. We have discovered a single point mutation that eliminates functionality without interfering with gap junction formation. The mutation occurs at a threonine residue located near the cytoplasmic end of the third transmembrane helix. This threonine is strictly conserved among members of the alpha- and beta-connexin subgroups but not the gamma-subgroup. In HeLa cells, connexin43 and connexin26 mutants are synthesized, traffic to the plasma membrane, and make gap junctions with the same overall appearance as wild type. We have isolated connexin26T135A gap junctions both from HeLa cells and baculovirus-infected insect Sf9 cells. By using cryoelectron microscopy and correlation averaging, difference images revealed a small but significant size change within the pore region and a slight rearrangement of the subunits between mutant and wild-type connexons expressed in Sf9 cells. Purified, detergent-solubilized mutant connexons contain both hexameric and partially disassembled structures, although wild-type connexons are almost all hexameric, suggesting that the three-dimensional mutant connexon is unstable. Mammalian cells expressing gap junction plaques composed of either connexin43T154A or connexin26T135A showed an absence of dye coupling. When expressed in Xenopus oocytes, these mutants, as well as a cysteine substitution mutant of connexin50 (connexin50T157C), failed to produce electrical coupling in homotypic and heteromeric pairings with wild type in a dominant-negative effect. This mutant may be useful as a tool for knocking down or knocking out connexin function in vitro or in vivo. 相似文献
110.
Sastry BS Suresh Babu K Hari Babu T Chandrasekhar S Srinivas PV Saxena AK Madhusudana Rao J 《Bioorganic & medicinal chemistry letters》2006,16(16):4391-4394
Nimbolide (1), a limonoid isolated from Azadirachta indica, is the chief cytotoxic principle in Neem leaves extract. Using nimbolide as a lead compound for anti-cancer analogue design, a series of nimbolide derivatives have been synthesized and evaluated for in vitro cytotoxic activity against a panel of human cancer cell lines. Out of 10 compounds screened 2g, 2h and 2i showed potent activity. 相似文献