Publications by authors named "Grace Chiou"

Summary: The authors present indocyanine green angiography to assess the effects of hyperbaric oxygen therapy and as a potential biomarker to predict healing of chronic wounds. They hypothesize that favorable initial response to hyperbaric oxygen therapy (improved perfusion) would be an early indicator of eventual response to the treatment (wound healing). Two groups were recruited: patients with chronic wounds and unwounded healthy controls.

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Chronic wounds affect roughly 6.5 million patients in the US annually. Current standard of therapy entails weekly sharp debridement.

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Background: Suboptimal healing of the tendon-bone interface remains an unsolved problem. The authors hypothesized that (1) platelet-rich plasma and prolonged in vitro incubation will produce interface scaffolds with greater reseeding of viable adipose-derived stem cells; and (2) when implanted with extracellular matrix hydrogel, constructs will display superior in vivo strength repair and biocompatibility.

Methods: Achilles-calcaneal composite tendon-bone interface scaffold grafts were harvested from 30 Wistar rats.

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Introduction: Plastic surgeons are often asked to assist with the reconstruction of lower extremity wounds. These patients many times require free tissue transfer for coverage given paucity of soft tissue. Anecdotally, many orthopedic surgeons prefer muscle coverage--particularly in the setting of potentially infected bone.

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Background: The authors have developed a tendon hydrogel that may be injected into the site of tendon injury to improve speed and strength of repair. The aim of this study was to compare the biological and physical properties of fresh, hydrated tendon hydrogel with its reconstituted lyophilized counterpart with the goal of increasing clinical feasibility.

Materials: Hydrogel was prepared from fresh human cadaveric flexor tendon.

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Purpose: Periarterial sympathectomy is a treatment option for patients with systemic sclerosis (SSc) suffering from digital vasculopathy. Despite potential benefits of ulcer healing, pain improvement, and amputation prevention, this operation appears to be infrequently performed. The aims of our study are as follows: (1) to assess national digital sympathectomy rates in patients with SSc and (2) to improve our understanding of referring physicians' perceptions of operative management and access to hand surgeons.

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Background: Tendon hydrogel is a promising new injectable substance that has been shown to improve repair strength after tendon injury. This study assesses the capacity of platelet-rich plasma to stimulate proliferation and migration of rat adipose-derived stem cells in tendon hydrogel in vitro.

Methods: To assess proliferation, adipose-derived stem cells were exposed to plasma, plasma supplemented with growth factors, or platelet-rich plasma in culture medium and tendon hydrogel.

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Introduction: Acute and chronic tendon injuries would benefit from stronger and more expeditious healing. We hypothesize that supplementation of a biocompatible tendon hydrogel with platelet-rich plasma (PRP) and adipose-derived stem cells (ASCs) would augment the tendon healing process.

Materials And Methods: Using 55 Wistar rats, a full-thickness defect was created within the midsubstance of each Achilles tendon with the addition of one of five experimental conditions: (i) saline control (50-μL), (ii) tendon hydrogel (50-μL), (iii) tendon hydrogel (45-μL)+PRP (5-μL), (iv) tendon hydrogel (45-μL)+2×10(6)-ASCs/mL in phosphate buffered saline (5-μL), and (v) tendon hydrogel (45-μL)+2×10(6)-ASCs/mL in PRP (5-μL).

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The communesins are a prominent class of indole alkaloids isolated from Penicillium species. Owing to their daunting structural framework and potential as pharmaceuticals, communesins have inspired numerous synthetic studies. However, the genetic and biochemical basis of communesin biosynthesis has remained unexplored.

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Purpose: Previous work has characterized the development of a human tendon hydrogel capable of improving mechanical strength after tendon injury. Animal tendon hydrogel has not yet been described, but would prove beneficial due to the cost and ethical concerns associated with the use of human cadaveric tendon. This study details the manufacture and assesses the biocompatibility of porcine tendon hydrogel seeded with human adipoderived stem cells (ASCs).

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Background: For patients with acute pancreatitis complicated by infected necrosis, minimally invasive techniques have taken hold without substantial comparison with open surgery. We present a contemporary series of open necrosectomies as a benchmark for newer techniques.

Methods: Using a prospective database, we retrospectively identified consecutive patients undergoing debridement for necrotizing pancreatitis (2006 to 2009).

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The traumatized hand often has soft tissue loss requiring flap reconstruction. Before proceeding with flap selection, the need for future refinement and secondary surgery should be taken into consideration. Although muscle flaps may offer better contour, fasciocutaneous flaps allow easier secondary flap elevation.

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The advent and proliferation of commercially available biologic mesh material has expanded the repertoire of hernia repair materials available to the surgeon. Given the higher initial cost of these mesh materials relative to synthetic materials such as polypropylene, there has been debate regarding the purported benefit of the use of biologic mesh. This study is a single-institution review of complex hernia repairs using both biologic and synthetic mesh materials.

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A strategy for introducing structural diversity into polyketides by exploiting the promiscuity of an in-line methyltransferase domain in a multidomain polyketide synthase is reported. In vitro investigations using the highly-reducing fungal polyketide synthase CazF revealed that its methyltransferase domain accepts the nonnatural cofactor propargylic Se-adenosyl-l-methionine and can transfer the propargyl moiety onto its growing polyketide chain. This propargylated polyketide product can then be further chain-extended and cyclized to form propargyl-α pyrone or be processed fully into the alkyne-containing 4'-propargyl-chaetoviridin A.

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The echinocandins are a small group of fungal N-acylated cyclic hexapeptides that are fungicidal for candida strains and fungistatic for aspergilli by targeting cell wall 1,3-β-glucan synthases. The side chains of all six amino acid building blocks have hydroxyl groups, including the nonproteinogenic 4R,5R-dihydroxy-Orn1, 4R-OH-Pro3, 3S,4S-dihydroxy-homoTyr4, and 3S-OH-4S-Me-Pro6. The echinocandin (ecd) gene cluster contains two predicted nonheme mononuclear iron oxygenase genes (ecdG,K) and one encoding a P450 type heme protein (ecdH).

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We report the identification and characterization of the caz biosynthetic cluster from Chaetomium globosum and the characterization of a highly reducing polyketide synthase (PKS) that acts in both a sequential and convergent manner with a nonreducing PKS to form the chaetomugilin and chaetoviridin azaphilones. Genetic inactivation studies verified the involvement of individual caz genes in the biosynthesis of the azaphilones. Through in vitro reconstitution, we demonstrated the in vitro synthesis of chaetoviridin A from the pyranoquinone intermediate cazisochromene using the highly reducing PKS and an acyltransferase.

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The Morgagni-type anterior diaphragmatic hernia is a congenital defect that is a very uncommon hernia presenting in an adult. Surgical repair is usually recommended upon diagnosis and often requires synthetic mesh for a durable, tension-free repair. The use of synthetic mesh concurrently with several of bariatric operations is controversial owing to the potential for mesh infection.

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A concise approach toward the total synthesis of the communesin alkaloids and perophoramidine is reported. The strategy relies on the use of the interrupted Fischer indolization to build the tetracyclic indoline core of the natural products. Studies to probe the scope and limitations of this plan are presented.

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A concise synthesis of the Alzheimer's therapeutic (+)-phenserine is described. The approach features an interrupted Fischer indolization to construct the pyrrolidinoindoline core, in addition to a classical resolution to arrive at phenserine in enantioenriched form.

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Dirhodium caprolactamate, Rh(2)(cap)(4), is a very efficient catalyst for the generation of the tert-butylperoxy radical from tert-butyl hydroperoxide, and the tert-butylperoxy radical is a highly effective oxidant for phenols and anilines. These reactions are performed with 70% aqueous tert-butyl hydroperoxide using dirhodium caprolactamate in amounts as low as 0.01 mol % to oxidize para-substituted phenols to 4-(tert-butyldioxy)cyclohexadienones.

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Objective: To determine the prevalence of brain abnormalities identified by prenatal imaging of fetuses with cleft lip with or without cleft palate (CL/P) or cleft palate only (CP) and to compare with postnatal imaging and neurologic evaluation.

Design: This was a retrospective review of radiologic images (magnetic resonance imaging [MRI] and sonography) of fetuses diagnosed with CL/P or CP at the Advanced Fetal Care Center at Children's Hospital Boston between 2002 and 2008. Images were reviewed for possible brain abnormalities by a pediatric radiologist who specializes in this field.

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Background: Delirium tremens (DT) in trauma patients is associated with significant morbidity and mortality. Short interview tools have been used to determine the risk of DT but require an alert, compliant patient and a motivated physician. The mean corpuscular volume (MCV) and aspartate aminotransferase (AST) levels are parts of routine laboratory testing, influenced by excessive alcohol consumption, and may serve as predictors of DT.

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Dirhodium(II) caprolactamate exhibits optimal efficiency for the production of the tert-butylperoxy radical, which is a selective reagent for hydrogen atom abstraction. These oxidation reactions occur with aqueous tert-butyl hydroperoxide (TBHP) without rapid hydrolysis of the caprolactamate ligands on dirhodium. Allylic oxidations of enones yield the corresponding enedione in moderate to high yields, and applications include allylic oxidations of steroidal enones.

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In order to discover novel immunomodulators for application in treating autoimmune diseases, a stable Jurkat transfectant was constructed in which luciferase reporter gene is driven by a full-length IL-2 promotor. A chemical library was screened to identify compounds that inhibited luciferase expression in Jurkat transfectants stimulated with PMA and ionomycin. A class of compounds (bis-trifluoromethyl pyrazole, BTPs) was identified from this screen.

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In a search for novel early T cell activation transcripts, we identified expressed sequence tags (ESTs) more abundantly expressed in normal human CD4(+) T lymphocytes fully activated by a 5 h exposure to CD3 plus CD28 mAbs, compared to the same cells stimulated with either CD3 mAb or CD28 mAb alone. An EST was identified that hybridized with a 1.7 kb transcript expressed in activated T cells but was undetectable by Northern blot analysis in resting T cells or other normal tissues.

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