Comparative Effectiveness of Two Ultrasound-Guided Regional Block Techniques for Surgical Anesthesia in Open Unilateral Inguinal Hernia Repair
JOURNAL OF ULTRASOUND IN MEDICINE
2016; 35 (1): 177-182
Unfolded Protein Response Regulation in Keloid Cells
JOURNAL OF SURGICAL RESEARCH
2011; 167 (1): 151-157
Transversus abdominis plane (TAP) and ilioinguinal/iliohypogastric (II/IH) nerve blocks have been described as analgesic adjuncts for inguinal hernia repair, but the efficacy of these techniques in providing intraoperative anesthesia, either individually or together, is not known. We designed this retrospective cohort study to test the hypothesis that combining TAP and II/IH nerve blocks ("double TAP" technique) results in greater accordance between the preoperative anesthetic plan and actual anesthetic technique provided when compared to TAP alone. Based on this study, double TAP may be preferred for patients undergoing open inguinal hernia repair who wish to avoid general anesthesia.
View details for DOI 10.7863/ultra.15.02057
View details for Web of Science ID 000367228500021
Engineered epidermal growth factor mutants with faster binding on-rates correlate with enhanced receptor activation
2011; 585 (8): 1135-1139
Keloids are a common form of pathologic wound healing characterized by excessive production of extracellular matrix. The unfolded protein response (UPR) is a cellular response to hypoxia, a component of the wound microenvironment, capable of protecting cells from the effects of over-accumulation of misfolded proteins. Since keloids have hypersecretion of extracellular matrix, we hypothesized that keloid fibroblasts (KFs) may have enhanced activation of the UPR compared with normal fibroblasts (NFs).KFs and NFs were placed in a hypoxia chamber for 0, 24, and 48h. We also used tunicamycin to specifically up-regulate the UPR. UPR activation was assayed by PCR for xbp-1 splicing and by immunoblotting with specific antibodies for the three UPR transducers. Nuclear localization of XBP-1 protein in KFs was confirmed by immunofluorescence.There is increased activation of XBP-1 protein in KFs compared with NFs following exposure to hypoxia. Pancreatic ER kinase (PERK) and ATF-6, two other pathways activated by the UPR, show comparable activation between KFs and NFs. We confirmed that there is enhanced activation of XBP-1 by demonstrating increased nuclear localization of XBP-1 using immunofluorescence.In contrast to our initial hypothesis that keloids would have broad activation of the UPR, we demonstrate here that there is a specific up-regulation of one facet of the UPR response. This may represent a specific molecular defect in KFs compared with NFs, and also suggests modulation of the UPR can be used in wound healing therapy.
View details for DOI 10.1016/j.jss.2009.04.036
View details for Web of Science ID 000288744100029
View details for PubMedID 19631342
Human melanoma-initiating cells express neural crest nerve growth factor receptor CD271
2010; 466 (7302): 133-U155
Receptor tyrosine kinases (RTKs) regulate critical cell signaling pathways, yet the properties of their cognate ligands that influence receptor activation are not fully understood. There is great interest in parsing these complex ligand-receptor relationships using engineered proteins with altered binding properties. Here we focus on the interaction between two engineered epidermal growth factor (EGF) mutants and the EGF receptor (EGFR), a model member of the RTK superfamily. We found that EGF mutants with faster kinetic on-rates stimulate increased EGFR activation compared to wild-type EGF. These findings support previous predictions that faster association rates correlate with enhanced receptor activity.
View details for DOI 10.1016/j.febslet.2011.03.044
View details for Web of Science ID 000289505400004
View details for PubMedID 21439278
Cell Permeant Peptide Analogues of the Small Heat Shock Protein, HSP20, Reduce TGF-beta 1-Induced CTGF Expression in Keloid Fibroblasts
JOURNAL OF INVESTIGATIVE DERMATOLOGY
2009; 129 (3): 590-598
The question of whether tumorigenic cancer stem cells exist in human melanomas has arisen in the last few years. Here we show that in melanomas, tumour stem cells (MTSCs, for melanoma tumour stem cells) can be isolated prospectively as a highly enriched CD271(+) MTSC population using a process that maximizes viable cell transplantation. The tumours sampled in this study were taken from a broad spectrum of sites and stages. High-viability cells isolated by fluorescence-activated cell sorting and re-suspended in a matrigel vehicle were implanted into T-, B- and natural-killer-deficient Rag2(-/-)gammac(-/-) mice. The CD271(+) subset of cells was the tumour-initiating population in 90% (nine out of ten) of melanomas tested. Transplantation of isolated CD271(+) melanoma cells into engrafted human skin or bone in Rag2(-/-)gammac(-/-) mice resulted in melanoma; however, melanoma did not develop after transplantation of isolated CD271(-) cells. We also show that in mice, tumours derived from transplanted human CD271(+) melanoma cells were capable of metastatsis in vivo. CD271(+) melanoma cells lacked expression of TYR, MART1 and MAGE in 86%, 69% and 68% of melanoma patients, respectively, which helps to explain why T-cell therapies directed at these antigens usually result in only temporary tumour shrinkage.
View details for DOI 10.1038/nature09161
View details for Web of Science ID 000279343800049
View details for PubMedID 20596026
Use of organotypic coculture to study keloid biology
AMERICAN JOURNAL OF SURGERY
2008; 195 (2): 144-148
A growing body of evidence suggests the involvement of connective tissue growth factor (CTGF) in the development and maintenance of fibrosis and excessive scarring. As the expression of this protein requires an intact actin cytoskeleton, disruption of the cytoskeleton represents an attractive strategy to decrease CTGF expression and, consequently, excessive scarring. The small heat-shock-related protein (HSP20), when phosphorylated by cyclic nucleotide signaling cascades, displaces phospho-cofilin from the 14-3-3 scaffolding protein leading to activation of cofilin as an actin-depolymerizing protein. In the present study, we evaluated the effect of AZX100, a phosphopeptide analogue of HSP20, on transforming growth factor-beta-1 (TGF-beta1)-induced CTGF and collagen expression in human keloid fibroblasts. We also examined the effect of AZX100 on scar formation in vivo in dermal wounds in a Siberian hamster model. AZX100 decreased the expression of CTGF and type I collagen induced by TGF-beta1, endothelin, and lysophosphatidic acid. Treatment with AZX100 decreased stress fiber formation and altered the morphology of human dermal keloid fibroblasts. In vivo, AZX100 significantly improved collagen organization in a Siberian hamster scarring model. Taken together, these results suggest the potential use of AZX100 as a strategy to prevent excessive scarring and fibrotic disorders.
View details for DOI 10.1038/jid.2008.264
View details for Web of Science ID 000263569500011
View details for PubMedID 18787533
Comparison of aesthetic breast reconstruction after skin-sparing or conventional mastectomy, in patients receiving preoperative radiation therapy
ANNALS OF PLASTIC SURGERY
2007; 59 (1): 78-81
Keloids are pathologic scars afflicting a large segment of our population and for which there is no definitive therapy. The lack of an animal model for keloid formation has hampered study. We developed an in vitro organotypic skin model to simulate normal keloid biology, which may allow us to study keloid formation without an animal model.Normal (NFs) and keloid (KFs) human fibroblasts were cultured in a collagen matrix to create a 3-dimensional dermal structure. Normal human keratinocytes (NKs) were cultured as a second layer on top and exposed to an air-fluid interface to allow differentiation into a mature keratinocyte layer. The organotypic skin was maintained for 28 days in Dulbecco's modified eagle medium with 10% fetal calf serum. Samples were collected, processed, sectioned, stained with hematoxylin and eosin, and then measured for qualitative analysis. alpha-smooth-muscle actin was also evaluated by immunoblotting.KF/NK organotypic skin showed increased collagen deposition, based on significantly denser collagen staining, with increased dermal thickness compared with NF/NK organotypic skin. We saw increased contracture in the KF/NK construct, and this correlated with increased organization of alpha-smooth-muscle actin fibers in the dermal layer of KF/NK organotypic skin compared with NF/NK skin.We have shown that coculture of KFs with keloid keratinocytes leads to an increased collagen production and dermal contracture compared with NFs and NKs, consistent with known keloid behavior. Given the lack of an animal model, we believe that organotypic skin culture can serve as a surrogate to study keloid formation.
View details for DOI 10.1016/j.amjsurg.2007.10.003
View details for Web of Science ID 000252598400002
View details for PubMedID 18070722
Many options exist for the surgical treatment of breast cancer in terms of tumor extirpation and reconstruction. Skin-sparing mastectomy (SSM) with immediate reconstruction offers patients a superior result, but this can be jeopardized by preoperative radiotherapy. We compared the outcomes of reconstruction after SSM or conventional mastectomy (CM) in the previously irradiated breast. We evaluated 41 patients over an 8-year period, who were divided into 3 categories: preoperative radiotherapy prior to SSM (n = 8), CM after preoperative radiation therapy (n = 9), and no chest wall irradiation prior to SSM (n = 20). The first group demonstrated significantly higher frequency of native flap compromise and capsular contracture formation than the other 2 groups.SSM with TRAM or latissimus with implant reconstruction is an esthetically optimal option for the treatment of patients without previous radiotherapy. However, for patients with preoperative chest wall radiation, TRAM flap reconstruction was superior to latissimus flap with implant after SSM.
View details for DOI 10.1097/01.sap.0000252487.27077.d6
View details for Web of Science ID 000247499400026
View details for PubMedID 17589266