Recent Stanford Publications in PubMedSubscribe to Recent Stanford Publications in PubMed
- Collective effects in a diffraction-limited storage ring.Nagaoka R, Bane KLJ Synchrotron Radiat
- Loss of pattern separation performance in schizophrenia suggests dentate gyrus dysfunction.Das T, Ivleva EI, Wagner AD, Stark CE, Tamminga CASchizophr Res
- What is the future of training in surgery? Needs assessment of national stakeholders.Kim S, Dunkin BJ, Paige JT, Eggerstedt JM, Nicholas C, Vassilliou MC, Spight DH, Pliego JF, Rush RM, Lau JN, Carpenter RO, Scott DJSurgery
- Guided and magnetic self-assembly of tunable magnetoceptive gels.Tasoglu S, Yu CH, Gungordu HI, Guven S, Vural T, Demirci UNat Commun
- PNA binding to the non-template DNA strand interferes with transcription, suggesting a blockage mechanism mediated by R-loop formation.Belotserkovskii BP, Hanawalt PCMol Carcinog
- Novel osteoinductive photo-cross-linkable chitosan-lactide-fibrinogen hydrogels enhance bone regeneration in critical size segmental bone defects.Kim S, Bedigrew K, Guda T, Maloney WJ, Park S, Wenke JC, Yang YPActa Biomater
- HLA desensitization with bortezomib in a highly sensitized pediatric patient.May LJ, Yeh J, Maeda K, Tyan DB, Chen S, Kaufman BD, Bernstein D, Rosenthal DN, Hollander SAPediatr Transplant
- Stromal responses among common carcinomas correlated with clinicopathologic features.Chen JL, Espinosa I, Lin AY, Liao OY, van de Rijn M, West RBClin Cancer Res
- Sociodemographic, psychiatric and somatic risk factors for suicide: a Swedish national cohort study.Crump C, Sundquist K, Sundquist J, Winkleby MAPsychol Med
Collective effects in a diffraction-limited storage ring.
J Synchrotron Radiat. 2014 Sep 1;21(Pt 5):937-960
Authors: Nagaoka R, Bane KL
This paper gives an overview of collective effects that are likely to appear and possibly limit the performance in a diffraction-limited storage ring (DLSR) that stores a high-intensity ultra-low-emittance beam. Beam instabilities and other intensity-dependent effects that may significantly impact the machine performance are covered. The latter include beam-induced machine heating, Touschek scattering, intra-beam scattering, as well as incoherent tune shifts. The general trend that the efforts to achieve ultra-low emittance result in increasing the machine coupling impedance and the beam sensitivity to instability is reviewed. The nature of coupling impedance in a DLSR is described, followed by a series of potentially dangerous beam instabilities driven by the former, such as resistive-wall, TMCI (transverse mode coupling instability), head-tail and microwave instabilities. In addition, beam-ion and CSR (coherent synchrotron radiation) instabilities are also treated. Means to fight against collective effects such as lengthening of the bunch with passive harmonic cavities and bunch-by-bunch transverse feedback are introduced. Numerical codes developed and used to evaluate the machine coupling impedance, as well as to simulate beam instability using the former as inputs are described.
PMID: 25177983 [PubMed - as supplied by publisher]
Loss of pattern separation performance in schizophrenia suggests dentate gyrus dysfunction.
Schizophr Res. 2014 Aug 28;
Authors: Das T, Ivleva EI, Wagner AD, Stark CE, Tamminga CA
Motivated by evidence that the dentate gyrus differentially mediates the pattern separation (PS) component of declarative memory function and that dentate gyrus harbors molecular and cellular pathologies in schizophrenia, we examined whether PS performance is altered in volunteers with schizophrenia (SZV) relative to healthy volunteers (HV). In groups of well-characterized SZV (n=14) and HV (n=15), we contrasted performance on the Behavioral Pattern Separation (BPS) Task, acquiring two outcome measures, a PS parameter and a Recognition Memory (RM) parameter, as well as specific recognition data by stimulus type. The SZVs showed a significant decrement in PS performance relative to HV (mean±SEM, SZV: 3.1±2.7%; HV: 17.1±5.8%; p=0.039, d'=0.86); whereas SZV and HV did not significantly differ in RM performance (SZV: 50.1±8.1%; HV: 59.3±5.5%; p=0.350, d'=0.36). Moreover, the SZVs showed a selective defect in correctly identifying similar lure items (SZV: 24.0±3.7%; HV: 41.2±4.6%; p<0.05), but demonstrated no impairment in identifying targets and novel foils. These data suggest that the dentate gyrus is dysfunctional in schizophrenia, a feature that could contribute to declarative memory impairment in the disorder and possibly to psychosis, a conclusion consistent with the considerable molecular pathology in the dentate gyrus in schizophrenia.
PMID: 25176349 [PubMed - as supplied by publisher]
What is the future of training in surgery? Needs assessment of national stakeholders.
Surgery. 2014 Sep;156(3):707-17
Authors: Kim S, Dunkin BJ, Paige JT, Eggerstedt JM, Nicholas C, Vassilliou MC, Spight DH, Pliego JF, Rush RM, Lau JN, Carpenter RO, Scott DJ
BACKGROUND: The Curriculum Committee of the American College of Surgeons-Accredited Educational Institutes conducted a need assessment to (1) identify gaps between ideal and actual practices in areas of surgical care, (2) explore educational solutions for addressing these gaps, and (3) shape a vision to advance the future of training in surgery.
METHODS: National stakeholders were recruited from the committee members' professional network and interviewed via telephone. Interview questions targeted areas for improving surgical patient care, optimal educational solutions for training in surgery including simulation roles, and entities that should primarily bear training costs. We performed an iterative, qualitative analysis including member checking to identify key themes.
RESULTS: Twenty-two interviewees included state/national board representatives, risk managers, multispecialty faculty/program directors, nurses, trainees, an industry representative, and a patient. Surgeons' communication with patients, families, and team members was raised consistently by stakeholders as a way to establish clear expectations regarding pre-, peri-, and postoperative care. Other comments highlighted the surgeon's development and demonstration and maintenance of cognitive and technical skills, including surgical judgment. Stakeholders also reiterated the critical need for surgeons to engage in on-going self-assessment and professional development to identify and remediate recognized limitations. Recommended learning modalities for meeting surgeons' needs included active learning (deliberate practice, diverse patient experiences), experiential learning (simulation), and peer and mentored learning (preceptorship).
CONCLUSION: This first formal needs assessment of education for surgeons points to opportunities for educational programs in patient-centered communication, learning models that match preferences of new generations of trainees, and training in interprofessional/interdisciplinary team communication and teamwork.
PMID: 25175505 [PubMed - in process]
Guided and magnetic self-assembly of tunable magnetoceptive gels.
Nat Commun. 2014;5:4702
Authors: Tasoglu S, Yu CH, Gungordu HI, Guven S, Vural T, Demirci U
Self-assembly of components into complex functional patterns at microscale is common in nature, and used increasingly in numerous disciplines such as optoelectronics, microfabrication, sensors, tissue engineering and computation. Here, we describe the use of stable radicals to guide the self-assembly of magnetically tunable gels, which we call 'magnetoceptive' materials at the scale of hundreds of microns to a millimeter, each can be programmed by shape and composition, into heterogeneous complex structures. Using paramagnetism of free radicals as a driving mechanism, complex heterogeneous structures are built in the magnetic field generated by permanent magnets. The overall magnetic signature of final structure is erased via an antioxidant vitamin E, subsequent to guided self-assembly. We demonstrate unique capabilities of radicals and antioxidants in fabrication of soft systems with heterogeneity in material properties, such as porosity, elastic modulus and mass density; then in bottom-up tissue engineering and finally, levitational and selective assembly of microcomponents.
PMID: 25175148 [PubMed - as supplied by publisher]
PNA binding to the non-template DNA strand interferes with transcription, suggesting a blockage mechanism mediated by R-loop formation.
Mol Carcinog. 2014 Aug 30;
Authors: Belotserkovskii BP, Hanawalt PC
Peptide Nucleic Acids (PNAs) are artificial DNA mimics with superior nucleic acid binding capabilities. T7 RNA polymerase (T7 RNAP) transcription upon encountering PNA bound to the non-template DNA strand was studied in vitro. A characteristic pattern of blockage signals was observed, extending downstream from the PNA binding site, similar to that produced by G-rich homopurine-homopyrimidine (hPu-hPy) sequences and likely caused by R-loop formation. Since blocked transcription complexes in association with stable R-loops may interfere with replication and in some cases trigger apoptosis, targeted R-loop formation might be employed to inactivate selected cells, such as those in tumors, based upon their unique complement of expressed genes. © 2014 The Authors. Molecular Carcinogenesis published by Wiley Periodicals, Inc.
PMID: 25175074 [PubMed - as supplied by publisher]
Novel osteoinductive photo-cross-linkable chitosan-lactide-fibrinogen hydrogels enhance bone regeneration in critical size segmental bone defects.
Acta Biomater. 2014 Aug 28;
Authors: Kim S, Bedigrew K, Guda T, Maloney WJ, Park S, Wenke JC, Yang YP
The purpose of this study was to develop and characterize a novel photo-cross-linkable chitosan-lactide-fibrinogen (CLF) hydrogel and evaluate the efficacy of bone morphogenetic protein-2 (BMP-2) containing CLF hydrogel for osteogenesis in vitro and in vivo. We synthesized the CLF hydrogels and characterized their chemical structure, degradation rate, compressive modulus, and in vitro BMP-2 release kinetics. We evaluated bioactivities of the BMP-2 containing CLF hydrogels (0, 50, 100, and 500 ng/ml) in vitro using W-20-17 preosteoblast mouse bone marrow stromal cells and C2C12 mouse myoblast cells. The effect of BMP-2 containing CLF gels (0, 0.5, 1, 2, and 5μg) on bone formation was evaluated using rat critical size segmental bone defects for 4 weeks. FTIR spectra and SEM images showed chemical and structural changes by addition of fibrinogen into chitosan-lactide copolymer. Incorporation of fibrinogen molecules significantly increased compressive modulus of the hydrogels. In vitro BMP-2 release study showed initial burst releases from the CLF hydrogels followed by sustained releases, regardless of the concentration of the BMP-2 over 4 weeks. Cells in all groups were viable in the presence of the hydrogels regardless of BMP-2 doses, indicating non-cytotoxicity of hydrogels. Alkaline phosphate activity and mineralization of cells exhibited dose dependence on BMP-2 containing CLF hydrogels. Radiographs, microcomputed tomography, and histology confirmed that the BMP-2 containing CLF hydrogels prompted neo-osteogenesis and accelerated healing of the defects in a dose-dependent manner. Thus the CLF hydrogel is a promising delivery system of growth factors for bone regeneration.
PMID: 25174669 [PubMed - as supplied by publisher]
HLA desensitization with bortezomib in a highly sensitized pediatric patient.
Pediatr Transplant. 2014 Sep 1;
Authors: May LJ, Yeh J, Maeda K, Tyan DB, Chen S, Kaufman BD, Bernstein D, Rosenthal DN, Hollander SA
The proteasome inhibitor bortezomib has been used with variable success in the treatment of AMR following heart transplant. There is limited experience with this agent as a pretransplant desensitizing therapy. We report a case of successful HLA desensitization with a bortezomib-based protocol prior to successful heart transplantation. A nine-yr-old boy with dilated cardiomyopathy, not initially sensitized to HLA (cPRA of zero), required three days of ECMO, followed by implantation of a Heartmate II LVAD. Within six wk, the patient developed de novo class I IgG and C1q complement-fixing HLA antibodies with a cPRA of 100%. Two doses of IVIG (2 g/kg) failed to reduce antibody levels, although two courses of a novel desensitization protocol consisting of rituximab (375 mg/m(2) ), bortezomib (1.3 mg/m(2) × 5 doses), and plasmapheresis reduced his cPRA to 0% and 87% by the C1q and IgG assays, respectively. He underwent heart transplantation nearly two months later. The patient is now >one yr post-transplant, is free of both AMR and ACR, and has no detectable donor-specific antibodies by IgG or C1q. Proteasome inhibition with bortezomib and plasmapheresis may be an effective therapy for HLA desensitization pretransplant.
PMID: 25174602 [PubMed - as supplied by publisher]
Stromal responses among common carcinomas correlated with clinicopathologic features.
Clin Cancer Res. 2013 Sep 15;19(18):5127-35
Authors: Chen JL, Espinosa I, Lin AY, Liao OY, van de Rijn M, West RB
PURPOSE: We have previously characterized a tumor stroma expression signature in a subset of breast tumors that correlates with better clinical outcome. The purpose of this study is to determine whether this stromal signature, termed the "DTF fibroblast" (desmoid-type fibromatosis) signature, is specific to breast cancer or is a common stromal response found in different types of cancer.
EXPERIMENTAL DESIGNS: The DTF fibroblast signature was applied to gene expression profiles from five ovarian, five lung, two colon, and three prostate cancer expression microarray datasets. In addition, two different tissue microarrays of 204 ovarian tumors and 140 colon tumors were examined for the expression of previously characterized protein markers of DTF fibroblast signature. The DTF fibroblast stromal response was then correlated with clinicopathologic features.
RESULTS: The DTF fibroblast signature is robustly present in ovarian, lung, and colon carcinomas. Both expression microarray data and immunohistochemistry show that the subset of ovarian tumors with strong DTF fibroblast signature expression has statistically significant, worse survival outcomes. No reproducible survival differences were found in either the lung or the colon cancers. The prostate cancers failed to show a DTF fibroblast signature. Multivariant analysis showed that DTF fibroblast signature was significantly more prognostic than the proliferation status in ovarian carcinomas.
CONCLUSIONS: Our results suggest that the DTF fibroblast signature is a common tumor stroma signature in different types of cancer, including ovarian, lung, and colon carcinomas. Our findings provide further insight into the DTF fibroblast stromal responses across different types of carcinomas and their potential as prognostic and therapeutic targets.
PMID: 23804424 [PubMed - indexed for MEDLINE]
Sociodemographic, psychiatric and somatic risk factors for suicide: a Swedish national cohort study.
Psychol Med. 2014 Jan;44(2):279-89
Authors: Crump C, Sundquist K, Sundquist J, Winkleby MA
BACKGROUND: More effective prevention of suicide requires a comprehensive understanding of sociodemographic, psychiatric and somatic risk factors. Previous studies have been limited by incomplete ascertainment of these factors. We conducted the first study of this issue using sociodemographic and out-patient and in-patient health data for a national population.
METHOD: We used data from a national cohort study of 7,140,589 Swedish adults followed for 8 years for suicide mortality (2001-2008). Sociodemographic factors were identified from national census data, and psychiatric and somatic disorders were identified from all out-patient and in-patient diagnoses nationwide.
RESULTS: There were 8721 (0.12%) deaths from suicide during 2001-2008. All psychiatric disorders were strong risk factors for suicide among both women and men. Depression was the strongest risk factor, with a greater than 15-fold risk among women or men and even higher risks (up to 32-fold) within the first 3 months of diagnosis. Chronic obstructive pulmonary disease (COPD), cancer, spine disorders, asthma and stroke were significant risk factors among both women and men (1.4-2.1-fold risks) whereas diabetes and ischemic heart disease were modest risk factors only among men (1.2-1.4-fold risks). Sociodemographic risk factors included male sex, unmarried status or non-employment; and low education or income among men.
CONCLUSIONS: All psychiatric disorders, COPD, cancer, spine disorders, asthma, stroke, diabetes, ischemic heart disease and specific sociodemographic factors were independent risk factors for suicide during 8 years of follow-up. Effective prevention of suicide requires a multifaceted approach in both psychiatric and primary care settings, targeting mental disorders (especially depression), specific somatic disorders and indicators of social support.
PMID: 23611178 [PubMed - indexed for MEDLINE]
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