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van den Brink A, Vermijs G, Solignac A, Koo J, Kohlhepp JT, Swagten HJM, Koopmans B. Field-free magnetization reversal by spin-Hall effect and exchange bias. Nat Commun 2016; 7:10854. [PMID: 26940861 PMCID: PMC5411711 DOI: 10.1038/ncomms10854] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/27/2016] [Indexed: 11/09/2022] Open
Abstract
As the first magnetic random access memories are finding their way onto the market, an important issue remains to be solved: the current density required to write magnetic bits becomes prohibitively high as bit dimensions are reduced. Recently, spin–orbit torques and the spin-Hall effect in particular have attracted significant interest, as they enable magnetization reversal without high current densities running through the tunnel barrier. For perpendicularly magnetized layers, however, the technological implementation of the spin-Hall effect is hampered by the necessity of an in-plane magnetic field for deterministic switching. Here we interface a thin ferromagnetic layer with an anti-ferromagnetic material. An in-plane exchange bias is created and shown to enable field-free S HE-driven magnetization reversal of a perpendicularly magnetized Pt/Co/IrMn structure. Aside from the potential technological implications, our experiment provides additional insight into the local spin structure at the ferromagnetic/anti-ferromagnetic interface. Future information storage technology may exploit electrical currents to write the states of ferromagnetic nanoelements via spin torque effects. Here, the authors demonstrate such behaviour promoted by exchange bias from an interfaced antiferromagnet, which may help overcome practical device limitations.
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YU H, Koo J, Daruwalla, V, Beano H, Patel K, Wlodarski R, Danier S, Harvill M, Kakos R, Critchfield J. Does tumor size correlate with biochemistry marker when evaluating the short-term therapeutic response of liver metastatic neuroendocrine tumor to yttrium-90 radioembolization? J Vasc Interv Radiol 2016. [DOI: 10.1016/j.jvir.2015.12.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Carlson DA, Gluskin AB, Mogni B, Koo J, Sood R, Lin Z, Pandolfino JE. Esophageal diverticula are associated with propagating peristalsis: a study utilizing high-resolution manometry. Neurogastroenterol Motil 2016; 28:392-8. [PMID: 26646704 PMCID: PMC4760883 DOI: 10.1111/nmo.12739] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/30/2015] [Indexed: 12/24/2022]
Abstract
BACKGROUND Esophageal diverticula have been associated with esophageal motility disorders, most commonly achalasia. We aimed to evaluate high-resolution manometry (HRM) motility diagnoses and pressurization patterns in patients with esophageal diverticula. METHODS Patients were retrospectively identified for distal esophageal diverticula and previously completed HRM. High-resolution manometries were analyzed according to the Chicago Classification, and the pressure slope of the compartmentalization phase (time between upper esophageal sphincter closure and the transition zone) of esophageal bolus transit was measured. Pressure slopes were also measured in 10 asymptomatic volunteers (controls) for comparison. KEY RESULTS Nineteen patients (ages 31-83) were included. Eight (42%) patients had normal motility, five (26%) had esophagogastric junction outflow obstruction, and two (11%) had jackhammer esophagus; four patients had other motility diagnoses including only one patient with achalasia. A total of six patients (32%) had at least one hypercontractile swallow. Greater compartmentalization phase pressure slopes were observed in patients at the mid-esophageal body in both supine (median [interquartile range]: 1.9 mmHg/s [0.9, 3.6]) and upright (1.1 [0.1, 3.1]) positions than in controls (supine: -1.3 [-2.4, -0.11], p = 0.001; upright; -0.71 [-2.1, -0.02], p = 0.005). CONCLUSIONS & INFERENCES Propagating peristalsis, often with hypercontractility, was commonly seen in our cohort of patients with esophageal diverticula. Abnormal compartmentalization phase pressurization may indicate a relationship of abnormal esophageal wall mechanics and/or compliance with diverticula; however whether these findings are causal or reactionary remains unclear.
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Lee K, Song K, Koo J. Delayed appearance of diffusion high signal after recanalization. J Neurol Sci 2015. [DOI: 10.1016/j.jns.2015.08.1388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Koo J, Yoon M, Chung W, Kim D. SU-E-T-617: Plan Quality Estimation of Intensity-Modulated Radiotherapy Cases for Lung Cancer. Med Phys 2015. [DOI: 10.1118/1.4924980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Kang Y, Jang H, Kim Y, Choi B, Kim J, Lee J, Shin H, Kim S, Kay C, Park S, Ji S, Koo J, Jeon S, Lee S. The Feasibility Study of MRI-Based Dose Calculation With Look-up Table in Radiation Treatment Planning. Int J Radiat Oncol Biol Phys 2014. [DOI: 10.1016/j.ijrobp.2014.05.2496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kim H, Kim B, Suk J, Park J, Jung S, Sun S, Koo J, Lee S. Efficacy of adenosylcobalamin in relieving xerotic pruritus symptoms of atopic dermatitis. J Eur Acad Dermatol Venereol 2013; 28:254-5. [DOI: 10.1111/jdv.12149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 02/26/2013] [Indexed: 11/29/2022]
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Koo J, Zavras A. Antiepileptic drugs (AEDs) during pregnancy and risk of congenital jaw and oral malformation. Oral Dis 2013; 19:712-20. [DOI: 10.1111/odi.12061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 10/28/2012] [Accepted: 11/29/2012] [Indexed: 11/28/2022]
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Park J, Cho BG, Kim KD, Koo J, Jang H, Ko KT, Park JH, Lee KB, Kim JY, Lee DR, Burns CA, Seo SSA, Lee HN. Oxygen-vacancy-induced orbital reconstruction of Ti ions at the interface of LaAlO3/SrTiO3 heterostructures: a resonant soft-X-ray scattering study. PHYSICAL REVIEW LETTERS 2013; 110:017401. [PMID: 23383835 DOI: 10.1103/physrevlett.110.017401] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Indexed: 06/01/2023]
Abstract
Resonant soft-x-ray scattering measurements have been performed to investigate interface electronic structures of (LaAlO(3)/SrTiO(3)) superlattices. Resonant scattering intensities at superlattice reflections show clear evidence of degeneracy lifting in t(2g) states of interface Ti ions. Polarization dependence of intensities indicates the energy of d(xy) states is lower by ~1 eV than two other t(2g) states. The energy splitting is insensitive to epitaxial strain. The orbital reconstruction is induced by oxygen vacancies and confined to the interface within two unit cells, indicating charge compensation at the polar interfaces.
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Park K, Wu J, Koo J. A randomized, ‘head-to-head’ pilot study comparing the effects of etanercept monotherapy vs. etanercept and narrowband ultraviolet B (NB-UVB) phototherapy in obese psoriasis patients. J Eur Acad Dermatol Venereol 2012; 27:899-906. [DOI: 10.1111/j.1468-3083.2012.04611.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Tammam S, Sampaleanu LM, Koo J, Sundaram P, Ayers M, Chong PA, Forman-Kay JD, Burrows LL, Howell PL. Characterization of the PilN, PilO and PilP type IVa pilus subcomplex. Mol Microbiol 2011; 82:1496-514. [PMID: 22053789 DOI: 10.1111/j.1365-2958.2011.07903.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Type IVa pili are bacterial nanomachines required for colonization of surfaces, but little is known about the organization of proteins in this system. The Pseudomonas aeruginosa pilMNOPQ operon encodes five key members of the transenvelope complex facilitating pilus function. While PilQ forms the outer membrane secretin pore, the functions of the inner membrane-associated proteins PilM/N/O/P are less well defined. Structural characterization of a stable C-terminal fragment of PilP (PilP(Δ71)) by NMR revealed a modified β-sandwich fold, similar to that of Neisseria meningitidis PilP, although complementation experiments showed that the two proteins are not interchangeable likely due to divergent surface properties. PilP is an inner membrane putative lipoprotein, but mutagenesis of the putative lipobox had no effect on the localization and function of PilP. A larger fragment, PilP(Δ18-6His), co-purified with a PilN(Δ44)/PilO(Δ51) heterodimer as a stable complex that eluted from a size exclusion chromatography column as a single peak with a molecular weight equivalent to two heterotrimers with 1:1:1 stoichiometry. Although PilO forms both homodimers and PilN-PilO heterodimers, PilP(Δ18-6His) did not interact stably with PilO(Δ51) alone. Together these data demonstrate that PilN/PilO/PilP interact directly to form a stable heterotrimeric complex, explaining the dispensability of PilP's lipid anchor for localization and function.
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Sodhi R, Gallaugher M, Wang Z, Koo J. Proposed ToF-SIMS/XPS standardization methods for bonding wires in electronic packaging applications. SURF INTERFACE ANAL 2011. [DOI: 10.1002/sia.3634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Koo J, Rafailovich MH, Medved L, Tsurupa G, Kudryk BJ, Liu Y, Galanakis DK. Evaluation of fibrinogen self-assembly: role of its αC region. J Thromb Haemost 2010; 8:2727-35. [PMID: 20880206 PMCID: PMC3057052 DOI: 10.1111/j.1538-7836.2010.04072.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Exposure of cryptic, functional sites on fibrinogen upon its adsorption to hydrophobic surfaces of biomaterials has been linked to an inflammatory response and fibrosis. Such adsorption also induces ordered fibrinogen aggregation which is poorly understood. OBJECTIVE To investigate hydrophobic surface-induced fibrinogen aggregation. METHODS Contact and lateral force scanning probe microscopy, yielding topography, image dimensions and fiber elastic modulus measurements were used along with transmission and scanning electron microscopy. Fibrinogen aggregation was induced under non-enzymatic conditions by adsorption on a trioctyl-surface monolayer (trioctylmethylamine) grafted onto silica clay plates. RESULTS A more than one molecule thick coating was generated by adsorption on the plate from 100 to 200 μg mL⁻¹ fibrinogen solutions, and three-dimensional networks formed from 4 mg mL⁻¹ fibrinogen incubated with uncoated or fibrinogen-coated plates. Fibrils appeared laterally assembled into branching and overlapping fibers whose heights from the surface ranged from approximately 3 to 740 nm. The elastic modulus of fibrinogen fibers was 1.55 MPa. No fibrils formed when fibrinogen lacking αC-domains was used as a coating or was incubated with intact fibrinogen-coated plates, or when the latter plates were sequentially incubated with anti-Aα529-539 mAb and intact fibrinogen. When an anti-Aα241-476 mAb was used instead, fine, long fibers formed. Similarly, sequential incubations of fibrinogen-coated plates with recombinant αC-domain (Aα392-610 fragment) or αC-connector (Aα221-372 fragment) and fibrinogen resulted in distinctly fine fiber networks. CONCLUSIONS Adsorption-induced fibrinogen self-assembly is initiated by a more than one molecule-thick surface layer and eventuates in three-dimensional networks whose formation requires fibrinogen with intact αC-domains.
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Ahn J, Jung M, Koo J, Moon Y, Park B, Kim S, Park S, Hong S, Kim J, Sohn J. Prediction of response in advanced breast cancer (ABC) patients who received trastuzumab-paclitaxel (TP): HER2 FISH ratio, expression of class III beta tubulin (bTubIII), and immunoglobulin G fragment C receptor (FCGR) polymorphisms. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.1101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Koga T, Li C, Endoh MK, Koo J, Rafailovich M, Narayanan S, Lee DR, Lurio LB, Sinha SK. Reduced viscosity of the free surface in entangled polymer melt films. PHYSICAL REVIEW LETTERS 2010; 104:066101. [PMID: 20366832 DOI: 10.1103/physrevlett.104.066101] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Indexed: 05/29/2023]
Abstract
By embedding "dilute" gold nanoparticles in single polystyrene thin films as "markers", we probe the local viscosity of the free surface at temperatures far above the glass transition temperature (T(g)). The technique used was x-ray photon correlation spectroscopy with resonance-enhanced x-ray scattering. The results clearly showed the surface viscosity is about 30% lower than the rest of the film. We found that this reduction is strongly associated with chain entanglements at the free surface rather than the reduction in T(g).
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Ayers M, Sampaleanu LM, Tammam S, Koo J, Harvey H, Howell PL, Burrows LL. PilM/N/O/P proteins form an inner membrane complex that affects the stability of the Pseudomonas aeruginosa type IV pilus secretin. J Mol Biol 2009; 394:128-42. [PMID: 19857645 DOI: 10.1016/j.jmb.2009.09.034] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 09/09/2009] [Accepted: 09/12/2009] [Indexed: 01/16/2023]
Abstract
The highly conserved pilM/N/O/P/Q gene cluster is among the core set of genes required for cell surface expression of type IV pili and associated twitching motility. With the exception of the outer membrane secretin, a multimer of PilQ subunits, the specific functions of the products encoded by this gene cluster are poorly characterized. Orthologous proteins in the related bacterial type II secretion system have been shown to interact to form an inner membrane complex required for protein secretion. In this study, we provide evidence that the PilM/N/O/P proteins form a functionally equivalent type IVa pilus complex. Using Pseudomonas aeruginosa as model organism, we found that all four proteins, including the nominally cytoplasmic PilM, colocalized to the inner membrane. Stability studies via Western blot analyses revealed that loss of one component has a negative impact on the levels of other members of the putative complex. Furthermore, complementation studies revealed that the stoichiometry of the components is important for the correct formation of a stable complex in vivo. We provide evidence that an intact inner membrane complex is required for optimal formation of the outer membrane complex of the type IVa pilus system in P. aeruginosa, as PilQ stability is negatively affected in its absence. Finally, we show that, in the absence of the pilin subunit, the levels of membrane-bound components of the inner membrane complex are negatively regulated by the PilR/S two-component system, suggesting a role for PilR/S in sensing the piliation status of the cell.
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Sampaleanu LM, Bonanno JB, Ayers M, Koo J, Tammam S, Burley SK, Almo SC, Burrows LL, Howell PL. Periplasmic domains of Pseudomonas aeruginosa PilN and PilO form a stable heterodimeric complex. J Mol Biol 2009; 394:143-59. [PMID: 19857646 DOI: 10.1016/j.jmb.2009.09.037] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 09/09/2009] [Accepted: 09/17/2009] [Indexed: 11/18/2022]
Abstract
Type IV pili (T4P) are bacterial virulence factors responsible for attachment to surfaces and for twitching motility, a motion that involves a succession of pilus extension and retraction cycles. In the opportunistic pathogen Pseudomonas aeruginosa, the PilM/N/O/P proteins are essential for T4P biogenesis, and genetic and biochemical analyses strongly suggest that they form an inner-membrane complex. Here, we show through co-expression and biochemical analysis that the periplasmic domains of PilN and PilO interact to form a heterodimer. The structure of residues 69-201 of the periplasmic domain of PilO was determined to 2.2 A resolution and reveals the presence of a homodimer in the asymmetric unit. Each monomer consists of two N-terminal coiled coils and a C-terminal ferredoxin-like domain. This structure was used to generate homology models of PilN and the PilN/O heterodimer. Our structural analysis suggests that in vivo PilN/O heterodimerization would require changes in the orientation of the first N-terminal coiled coil, which leads to two alternative models for the role of the transmembrane domains in the PilN/O interaction. Analysis of PilN/O orthologues in the type II secretion system EpsL/M revealed significant similarities in their secondary structures and the tertiary structures of PilO and EpsM, although the way these proteins interact to form inner-membrane complexes appears to be different in T4P and type II secretion. Our analysis suggests that PilN interacts directly, via its N-terminal tail, with the cytoplasmic protein PilM. This work shows a direct interaction between the periplasmic domains of PilN and PilO, with PilO playing a key role in the proper folding of PilN. Our results suggest that PilN/O heterodimers form the foundation of the inner-membrane PilM/N/O/P complex, which is critical for the assembly of a functional T4P complex.
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Park S, Koo J, Park HS, Kim JH, Choi SY, Lee JH, Park BW, Lee KS. Expression of androgen receptors in primary breast cancer. Ann Oncol 2009; 21:488-492. [PMID: 19887463 DOI: 10.1093/annonc/mdp510] [Citation(s) in RCA: 257] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND To investigate the clinicopathological significance of androgen receptor (AR) expression in primary breast cancers. PATIENTS AND METHODS We evaluated AR using immunohistochemistry from 413 whole sections from January 2008 to March 2009 and analyzed the relationship between AR and clinicopathological parameters. Tumors with >/=10% nuclear-stained cells were considered to be positive for AR. The differences among variables were calculated by chi-square test. RESULTS The expression rate of AR was 72.9% higher than those of estrogen receptors (ER) and progesterone receptors. AR expression was significant in patients with no elevated preoperative serum cancer antigen 15-3 levels, smaller tumor size, lower histologic grade and hormone receptor-positive and non-triple-negative breast cancer. However, AR expression was observed in 35% of triple-negative cancers. Metaplastic, medullary and mucinous types of carcinomas showed less AR expression. In the ER-negative subgroup, AR was significantly correlated with human epidermal growth factor receptor type 2 (HER-2) overexpression. CONCLUSIONS AR is expressed in a significant number of breast cancers and is associated with lower tumor burden and favorable differentiation. There are many issues to be further investigated such as whether AR is an independent prognostic factor, whether it is a therapeutic target for the triple-negative breast cancers and whether it is associated with HER-2 signaling in ER-negative tumors.
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Goodwin P, Pritchard K, Ennis M, Koo J, Hood N. 5160 Long-term prognostic effects of fasting insulin in early stage breast cancer (BC) patients. EJC Suppl 2009. [DOI: 10.1016/s1359-6349(09)71052-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Lee E, Koo J. Single‐center retrospective study of long‐term use of low‐dose acitretin (Soriatane®) for psoriasis. J DERMATOL TREAT 2009; 15:8-13. [PMID: 14754643 DOI: 10.1080/095466303100184473] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Indicated as monotherapy for severe psoriasis in adults, acitretin (Soriatane) can be used in combination therapy or as a 'disease-stabilizing, maintenance' agent. While its efficacy for psoriasis and other disorders of keratinization is well established, its safety is often a concern for many dermatologists. The possible side effects associated with short-term treatment of oral retinoids include mucocutaneous effects, elevation in serum lipid chemistries and liver enzymes, and teratogenicity. However, the only possible long-term, cumulative side effect is skeletal and ligamentous calcification such as hyperostosis. There is a specific syndrome of hyperostosis associated with oral retinoids called DISH (diffuse idiopathic skeletal hyperostosis). OBJECTIVE To examine the incidence of DISH syndrome in long-term acitretin use for psoriasis and to quantify the incidence of other side effects. METHODS All patients seen at the UCSF Psoriasis and Skin Treatment Center who had been on acitretin for more than 1 year were identified. RESULTS A chart review of these patients revealed no X-ray-confirmed cases of DISH syndrome, minimal changes in coronary heart disease risk indicators, and extremely rare significant elevation of liver enzymes. CONCLUSION Acitretin does not appear to cause significant long-term side effects at low doses; the implications for thousands of patients are that use of this medication can be continued for long periods of time with routine monitoring.
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Lee Y, Sohn J, Park B, Chung H, Suh C, Kim S, Koo J, Kim J, Choi H, Kim Y. Does hormone receptor (HR) positivity affect the prognosis in breast cancers with human epidermal growth factor receptor 2 (HER2) overexpression? J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.e22091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e22091 Background: Biologically, there is an unclear issue about the role of HR positivity in HER2 positive breast cancer. These HER2(+)/ HR(+) pts were grouped into luminal B type apart from HER2(+)/ HR(-) pts in molecular profiling. However, from the clinical point of view, these pts have been categorized and been treated as either the only HER2(+) disease regardless of HR status or vice versa. Thus, we investigated the impact of HR status on clinical outcomes in HER2-overexpressed breast cancers. Methods: We retrospectively reviewed medical charts of HER2-positive breast cancer pts who underwent curative surgical resection from 1996 to 2001 in the Severance hospital, Korea. Demographic comparisons were performed by Chi-square tests. Tumor size, nodal stage, TNM stage, HR status, and adjuvant tamoxifen use were included in the Cox proportional hazards model. Results: Among the total 174 HER2-positive pts, HR (n=93) was positive in 53.5% (n = 93) and HR-positive tumors were more likely to be premenopausal (73% v 52%; P=0.01) and well- differentiated (grade 1or 2; 77% v 62%; P=0.04). There were no significant differences according to HR status in terms of tumor size, nodal stage, TNM stage, operation methods, and chemotherapy regimen. In these HER2-positive pts, the 5-year disease free survival (DFS) was longer in HR(+) pts than in HR(-) pts (DFS; 82.9% v 61.5%; P= 0.01). In a subset analysis, the 5-year DFS of HER2(+)/ER(+) pts without adjuvant tamoxifen (n=26) was not different from that of HER2(+)/ ER(-) pts (DFS; 57.7% v 61.5%; P= 0.32). However, the 5-year DFS of HER2(+)/ ER(+) pts with adjuvant tamoxifen was significantly prolonged compared with that of HER2(+)/ ER(-) pts (DFS; 91.5% v 61.5%; P< 0.001). In a multivariate analysis of DFS, tumor size and adjuvant tamoxifen use significantly affected DFS with an adjusted hazard ratio of 2.56 (95% CI, 1.2–4.9; P= 0.01) and 6.58 (95% CI, 2.8–20.3; P< 0.001), respectively. Conclusions: In an analysis of HER2-overexpressed breast cancer, the presence of HR itself did not affect the prognosis. However, most of the survival benefit seems to be driven from adjuvant tamoxifen therapy not the HR status itself. No significant financial relationships to disclose.
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Salamon N, Kung J, Shaw SJ, Koo J, Koh S, Wu JY, Lerner JT, Sankar R, Shields WD, Engel J, Fried I, Miyata H, Yong WH, Vinters HV, Mathern GW. FDG-PET/MRI coregistration improves detection of cortical dysplasia in patients with epilepsy. Neurology 2009; 71:1594-601. [PMID: 19001249 DOI: 10.1212/01.wnl.0000334752.41807.2f] [Citation(s) in RCA: 199] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE Patients with cortical dysplasia (CD) are difficult to treat because the MRI abnormality may be undetectable. This study determined whether fluorodeoxyglucose (FDG)-PET/MRI coregistration enhanced the recognition of CD in epilepsy surgery patients. METHODS Patients from 2004-2007 in whom FDG-PET/MRI coregistration was a component of the presurgical evaluation were compared with patients from 2000-2003 without this technique. For the 2004-2007 cohort, neuroimaging and clinical variables were compared between patients with mild Palmini type I and severe Palmini type II CD. RESULTS Compared with the 2000-2003 cohort, from 2004-2007 more CD patients were detected, most had type I CD, and fewer cases required intracranial electrodes. From 2004-2007, 85% of type I CD cases had normal non-University of California, Los Angeles (UCLA) MRI scans. UCLA MRI identified CD in 78% of patients, and 37% of type I CD cases had normal UCLA scans. EEG and neuroimaging findings were concordant in 52% of type I CD patients, compared with 89% of type II CD patients. FDG-PET scans were positive in 71% of CD cases, and type I CD patients had less hypometabolism compared with type II CD patients. Postoperative seizure freedom occurred in 82% of patients, without differences between type I and type II CD cases. CONCLUSIONS Incorporating fluorodeoxyglucose-PET/MRI coregistration into the multimodality presurgical evaluation enhanced the noninvasive identification and successful surgical treatment of patients with cortical dysplasia (CD), especially for the 33% of patients with nonconcordant findings and those with normal MRI scans from mild type I CD.
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Koo J, Kang Y, Kleinstreuer C. A nonlinear effective thermal conductivity model for carbon nanotube and nanofiber suspensions. NANOTECHNOLOGY 2008; 19:375705. [PMID: 21832559 DOI: 10.1088/0957-4484/19/37/375705] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
It has been experimentally demonstrated that suspensions of carbon nanotubes (CNTs) and nanofibers (CNFs) significantly increase the thermal conductivity of nanofluids; however, a physically sound theory of the underlying phenomenon is still missing. In this study, the nonlinear nature of the effective thermal conductivity enhancement with the particle concentration of CNT and CNF nanofluids is explained physically using the excluded volume concept. Specifically, the number of contacting CNTs and CNFs could be calculated by using the excluded volume concept, where the distance for heat to travel in a cylinder between the contacting cylinders in the thermal network of percolating CNTs and CNFs increased with the excluded volume. In contrast to the effective thermal conductivity model of Sastry et al (2008 Nanotechnology 19 055704) the present revised model could reproduce the nonlinear increase of the thermal conductivity with particle concentration, as well as the dependence on the diameter and aspect ratio of the CNTs and CNFs. It was found that the alignment of CNTs and CNFs due to the long range repulsion force decreases the excluded volume, leading to both the convex and concave nonlinear as well as linear increase of the thermal conductivity with particle concentration. The difference between various carrier fluids of the suspensions could be explained as the result of the change in the excluded volume in different base fluids.
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Goodwin PJ, Ennis M, Pritchard KI, Koo J, Hood N. Frequency of vitamin D (Vit D) deficiency at breast cancer (BC) diagnosis and association with risk of distant recurrence and death in a prospective cohort study of T1–3, N0–1, M0 B. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.511] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Traoré PCS, Bostick WM, Jones JW, Koo J, Goïta K, Bado BV. A simple soil organic-matter model for biomass data assimilation in community-level carbon contracts. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2008; 18:624-636. [PMID: 18488622 DOI: 10.1890/07-1133.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Soil carbon (C) sequestration has been proposed as a transitional win-win strategy to help replenish organic-matter content in depleted agricultural soils and counter increases in atmospheric greenhouse gases. Data assimilation and remote sensing can reduce uncertainty in sequestered C mass estimates, but simple soil organic carbon (SOC) models are required to make operational predictions of tradeable amounts over large, heterogenous areas. Our study compared the performance of RothC26.3 and a reduced compartmental model on an 11-year fertilizer trial in subhumid West Africa. Root mean square error (RMSE) differences of 0.05 Mg C/ha between models on total SOC predictions suggest that for contractual purposes, SOC dynamics can be simulated by a two-pool structure with labile and stable components. Faster (seasonal) and slower (semicentennial and beyond) rates can be approximated by constants as instantaneous and infinite decay. In these systems, simulations indicate that cereal residue incorporation holds most potential for mitigation of transient C loss associated with recent land conversion to agriculture.
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