Gap Balancing vs. Measured Resection Technique in Total Knee Arthroplasty

Brian K. Daines,Douglas A. Dennis 대한정형외과학회 2014 Clinics in Orthopedic Surgery Vol.6 No.1

A goal of total knee arthroplasty is to obtain symmetric and balanced flexion and extension gaps. Controversy exists regarding the best surgical technique to utilize to obtain gap balance. Some favor the use of a measured resection technique in which bone landmarks, such as the transepicondylar, the anterior-posterior, or the posterior condylar axes are used to determine proper femoral component rotation and subsequent gap balance. Others favor a gap balancing technique in which the femoral component is positioned parallel to the resected proximal tibia with each collateral ligament equally tensioned to obtain a rectangular flexion gap. Two scientific studies have been performed comparing the two surgical techniques. The first utilized computer navigation and demonstrated a balanced and rectangular flexion gap was obtained much more frequently with use of a gap balanced technique. The second utilized in vivo video fluoroscopy and demonstrated a much high incidence of femoral condylar lift-off (instability) when a measured resection technique was used. In summary, the authors believe gap balancing techniques provide superior gap balance and function following total knee arthroplasty.

Gradient release of cardiac morphogens by photo-responsive polymer micelles for gradient-mediated variation of embryoid body differentiation

Gupta, Mukesh K.,Balikov, Daniel A.,Lee, Yunki,Ko, Edward,Yu, Christopher,Chun, Young Wook,Sawyer, Douglas B.,Kim, Won Shik,Sung, Hak-Joon Royal Society of Chemistry 2017 Journal of Materials Chemistry B Vol. No.

<P>Retinoic acid (RA) is a well-known morphogen in human development. However, how an RA gradient distribution influences cardiac development remains obscure due to the lack of appropriate experimental apparatus. To address this issue, a polymeric micelle system with covalently attached RA was engineered to deliver gradient quantities of RA upon photo-irradiation. A photo-degradable polymeric nanoparticle (NP) composed of an amphiphilic methoxy(polyethylene glycol)-<I>b</I>-poly(ε-caprolactone)-<I>co</I>-poly(azido-ε-caprolactone-<I>g-ortho</I> nitrobenzyl retinoic ester) copolymer was synthesized, and hanging RA was covalently attached through a photo-sensitive <I>o</I>-nitrobenzyl (ONB) linker. The ONB linker was efficiently cleaved when exposed to a light (365 nm)-gradient, and the consequent gradient release of RA from the micelles was demonstrated. The efficacy of the photo-gradient-mediated RA release was validated across different concentrations of polymer micelles over varied irradiation periods. It was confirmed that polymer micelles demonstrated minimal cytotoxicity when exposed to mouse embryoid bodies (EBs). Finally, when the photo-gradient release of polymer micelles was applied, GFP-cardiac troponin T reporter mouse EBs demonstrated a concurrent gradient-like pattern of cardiac differentiation, verifying the utility of our novel photo-gradient approach to study morphogen gradients not only for cardiac development but also for other potential biological microenvironments subject to morphogen presentation with highly defined spatial and temporal geometries.</P>

Expression profile of an operationally-defined neural stem cell clone

Parker, Mark A.,Anderson, Julia K.,Corliss, Deborah A.,Abraria, Victoria E.,Sidman, Richard L.,Park, Kook In,Teng, Yang D.,Cotanche, Douglas A.,Snyder, Evan Y. Elsevier 2005 Experimental neurology Vol.194 No.2

<P><B>Abstract</B></P><P>Neural stem cells (NSCs) are the most primordial and least committed cells of the nervous system, the cells that exist <I>before</I> regional specification develops. Because immunocytochemically-detectable markers that are sufficiently specific and sensitive to define an NSC have not yet been fully defined, we have taken the strong view that, to be termed a “stem cell” in the nervous system—in contrast to a “progenitor” or “precursor” (whose lineage commitment is further restricted)—a <I>single neuroectodermally-derived cell</I> must fulfill an operational definition that is essentially similar to that used in hematopoiesis. In other words, it must possess the following functional properties: (1) “Multipotency”, i.e., the ability to yield mature cells in all three fundamental neural lineages throughout the nervous system—neurons (of all subtypes), astrocytes (of all types), oligodendrocytes—in multiple regional and developmental contexts and in a region and developmental stage-appropriate manner. (2) The ability to populate a developing region and/or repopulate an ablated or degenerated region of the nervous system with appropriate cell types. (3) The ability to be serially transplanted. (4) “Self-renewal”, i.e., the ability to produce daughter cells (including new NSCs) with identical properties and potential. Having identified a murine neural cell clone that fulfills this strict operational definition—in contrast to other studies that used less rigorous or non-operational criteria for defining an NSC (e.g., the “neurosphere” assay)—we then examined, by comparing gene expression profiles, the relationship such a cell might have to (a) a <I>multipotent</I> somatic stem cell from another organ system (the hematopoietic stem cell [HSC]); (b) a <I>pluripotent</I> stem cell derived from the inner cell mass and hence without organ assignment (an embryonic stem cell); (c) neural cells isolated and maintained primarily as neurospheres but without having been subjected to the abovementioned operational screen (“CNS-derived neurospheres”). ESCs, HSCs, and operationally-defined NSCs—all of which have been identified not only by markers but by functional assays in their respective systems and whose state of differentiation could be synchronized—shared a large number of genes. Although, as expected, the most stem-like genes were expressed by ESCs, NSCs and HSCs shared a number of genes. CNS-derived neurospheres, on the other hand, expressed fewer “stem-like” genes held in common by the other operationally-defined stem cell populations. Rather they displayed a profile more consistent with differentiated neural cells. (Genes of neural identity were shared with the NSC clone.) Interestingly, when the operationally-defined NSC clone was cultured as a neurosphere (rather than in monolayer), its expression pattern shifted from a “stem-like” pattern towards a more “differentiated” one, suggesting that the neurosphere, without functional validation, may be a poor model for predicting stem cell attributes because it consists of heterogeneous populations of cells, only a small proportion of which are truly “stem-like”. Furthermore, when operational definitions are employed, a common set of stem-like genes does emerge across both embryonic and somatic stem cells of various organ systems, including the nervous system.</P>

Band Offsets in YSZ/InGaZnO₄ Heterostructure System

Kim, J.K.,Kim, K.-W.,Douglas, E.A.,Gila, B.P.,Craciun, V.,Lambers, E.S.,Norton, D.P.,Ren, F.,Pearton, S.J.,Cho, H. American Scientific Publishers 2014 Journal of Nanoscience and Nanotechnology Vol.14 No.5

The energy discontinuity in the valence band (Delta E-V) of Y2O3-stabilized ZrO2 (YSZ)/InGaZnO4 (IGZO) heterostructures was obtained from X-ray photoelectron spectroscopy (XPS) measurements. The YSZ exhibited a bandgap of 4.4 eV from absorption measurements. A value of Delta E-V = 0.57 +/- 0.12 eV was obtained by using Ga 2p(3/2), Zn 2p(3/2) and In 3d(5/2) energy levels as references. This implies a conduction band offset (Delta E-C) of 0.63 eV in YSZ/InGaZnO4 heterostructures and a nested interface band alignment.

Enhancement of the Antifungal Activity of Antimicrobial Drugs by Eugenia uniflora L.

Karla K.A. Santos,Edinardo F.F. Matias,Saulo R. Tintino,Celestina E.S. Souza,Maria F.B.M. Braga,Glaucia M.M. Guedes,Jose´ G.M. Costa,Irwin R.A. Menezes,Henrique Douglas Melo Coutinho 한국식품영양과학회 2013 Journal of medicinal food Vol.16 No.7

Candidiasis is the most frequent infection by opportunistic fungi such as Candida albicans, Candida tropicalis, and Candida krusei. Ethanol extract from Eugenia uniflora was assayed, for its antifungal activity, either alone or combined with four selected chemotherapeutic antimicrobial agents, including anphotericin B, mebendazole, nistatin, and metronidazole against these strains. The obtained results indicated that the association of the extract of E. uniflora to metronidazole showed a potential antifungal activity against C. tropicalis. However, no synergistic activity against the other strains was observed, as observed when the extract was associated with the other, not enhancing their antifungal activity.

Automatic Searching Algorithm for Galactic HI at Forbidden Velocities in the Inner-Galaxy ALFA Low-Latitude HI (I-GALFA) Survey

Kang Ji-hyun,Bon-Chul Koo,Gibson, S. J.,Douglas K. A.,Geumsook Park.,Peek J. E. G.,Korpela E. J.,Heiles C. E. 한국천문학회 2011 天文學會報 Vol.36 No.1

H I SHELLS AND SUPERSHELLS IN THE I-GALFA H I 21 cm LINE SURVEY. I. FAST-EXPANDING H I SHELLS ASSOCIATED WITH SUPERNOVA REMNANTS

Park, G.,Koo, B.-C.,Gibson, S. J.,Kang, J.-h.,Lane, D. C.,Douglas, K. A.,Peek, J. E. G.,Korpela, E. J.,Heiles, C.,Newton, J. H. IOP Publishing 2013 The Astrophysical journal Vol.777 No.1

<P>We search for fast-expanding Hi shells associated with Galactic supernova remnants (SNRs) in the longitude range l approximate to 32 degrees to 77 degrees using 21 cm line data from the Inner-Galaxy Arecibo L-band Feed Array (I-GALFA) Hi survey. Among the 39 known Galactic SNRs in this region, we find such Hi shells in 4 SNRs: W44, G54.4-0.3, W51C, and CTB 80. All four were previously identified in low-resolution surveys, and three of those (excluding G54.4-0.3) were previously studied with the Arecibo telescope. A remarkable new result, however, is the detection of Hi emission at both very high positive and negative velocities in W44 from the receding and approaching parts of the Hi expanding shell, respectively. This is the first detection of both sides of an expanding shell associated with an SNR in H I 21 cm emission. The high-resolution I-GALFA survey data also reveal a prominent expanding Hi shell with high circular symmetry associated with G54.4-0.3. We explore the physical characteristics of four SNRs and discuss what differentiates them from other SNRs in the survey area. We conclude that these four SNRs are likely the remnants of core-collapse supernovae interacting with a relatively dense (greater than or similar to 1 cm(-3)) ambient medium, and we discuss the visibility of SNRs in the H I 21 cm line.</P>