In JoVE (1)

Other Publications (7)

Articles by Robert J. Clements in JoVE

Other articles by Robert J. Clements on PubMed

Kaiser Permanente's Convergent Medical Terminology

Studies in Health Technology and Informatics. 2004  |  Pubmed ID: 15360832

This paper describes Kaiser Permanente's (KP) enterprise-wide medical terminology solution, referred to as our Convergent Medical Terminology (CMT). Initially developed to serve the needs of a regional electronic health record, CMT has evolved into a core KP asset, serving as the common terminology across all applications. CMT serves as the definitive source of concept definitions for the organization, provides a consistent structure and access method to all codes used by the organization, and is KP's language of interoperability, with cross-mappings to regional ancillary systems and administrative billing codes. The core of CMT is comprised of SNOMED CT, laboratory LOINC, and First DataBank drug terminology. These are integrated into a single poly-hierarchically structured knowledge base. Cross map sets provide bi-directional translations between CMT and ancillary applications and administrative billing codes. Context sets provide subsets of CMT for use in specific contexts. Our experience with CMT has lead us to conclude that a successful terminology solution requires that: (1) usability considerations are an organizational priority; (2) "interface" terminology is differentiated from "reference" terminology; (3) it be easy for clinicians to find the concepts they need; (4) the immediate value of coded data be apparent to clinician user; (5) there be a well defined approach to terminology extensions. Over the past several years, there has been substantial progress made in the domain coverage and standardization of medical terminology. KP has learned to exploit that terminology in ways that are clinician-acceptable and that provide powerful options for data analysis and reporting.

Distribution of Parvalbumin and Calretinin Immunoreactive Interneurons in Motor Cortex from Multiple Sclerosis Post-mortem Tissue

Experimental Brain Research. May, 2008  |  Pubmed ID: 18297277

Parvalbumin (PV) and calretinin (CR) are calcium binding proteins (CBP's) expressed in discrete GABAergic interneuron populations in the human cortex. CBP's are known to buffer calcium concentrations and protect neurons from increases in intracellular calcium. Perturbations in intracellular calcium can activate proteolytic enzymes including calpain, leading to deleterious effects to axons. Ca++-mediated mechanisms have been found to be associated with axonal pathology in MS and the restructuring of calcium channels has been shown to occur in experimental autoimmune encephalomyelitis (EAE) as well as multiple sclerosis tissue. Previous data indicates a reduction in the expression of the parvalbumin gene as well as reduced extension of neurites on parvalbumin expressing interneurons within multiple sclerosis normal appearing grey matter (NAGM). Modifications in interneuron parvalbumin or calretinin levels could change calcium buffering capacity, as well as the way these cells respond to neuronal insults. The present study was designed to compare CBP immunoreactive neurons in normal and multiple sclerosis post-mortem NAGM. To this end, we utilized immunofluorescent staining and high resolution confocal microscopy to map regions of the human motor cortex, and characterize layer specific CBP distribution in the normal and multiple sclerosis motor cortex. Our results indicate a significant reduction in the number of PV interneurons within layer 2 of the multiple sclerosis primary motor cortex with no concurrent change in number of calretinin positive neurons.

Effects of Intrauterine 2,3,7,8-tetrachlorodibenzo-p-dioxin on the Development and Function of the Gonadotrophin Releasing Hormone Neuronal System in the Male Rat

Reproductive Toxicology (Elmsford, N.Y.). Jul, 2009  |  Pubmed ID: 19490993

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental disrupter that continues to be generated from numerous industrial processes. In utero and lactational exposure of rats to levels of TCDD similar to those encountered by human populations have profound and persistent effects on growth, the reproductive axis and spatial learning and memory. TCDD is thought to act through the aryl hydrocarbon receptor, which displays crosstalk with estrogen-mediated genomic activation. An in vitro superfusion system was used to evaluate the effects of TCDD exposure on GnRH-release from hypothalamic explants at three developmental time points in male rats. Pregnant dams were treated with 5 microg/kg TCDD on gestational day 15, and male offspring displayed a marked reduction in GnRH release. However, total mediobasal hypothalamus/preoptic area (MBH/POA) GnRH content was significantly greater in dioxin-exposed animals. These results suggest deficits in release rather than production of GnRH. Confocal microscopy was used to characterize anatomical features of individual GnRH-positive neurons, as well as the organization of the neuronal network governing GnRH release. Differences in cellular structures were apparent in discrete regions of the GnRH neural network, specifically the lateral preoptic area and septal region. We propose that developmental reproductive effects in males treated in utero and lactionally with dioxin, results from a suppressive effect of TCDD on mechanisms governing GnRH release. These effects coincide with changes in growth and development, indicating that TCDD may induce a syndrome of effects by modifying hypothalamic structures regulating growth and reproductive development.

Angiotensin II-dependent Growth of Vascular Smooth Muscle Cells Requires Transactivation of the Epidermal Growth Factor Receptor Via a Cytosolic Phospholipase A(2)-mediated Release of Arachidonic Acid

Archives of Biochemistry and Biophysics. Jun, 2010  |  Pubmed ID: 20388488

Angiotensin (Ang) II stimulates vascular smooth muscle cell (VSMC) growth via activation of cytosolic phospholipase A(2) (cPLA(2)), release of arachidonic acid (ArAc) and activation of mitogen-activated protein kinase (MAPK). The mechanism linking AT(1) receptor stimulation of ArAc release with MAPK activation may involve transactivation of the epidermal growth factor receptor (EGFR). In this study, Ang II increased phosphorylation of the EGFR and MAPK in cultured VSMC and these effects were attenuated by the cPLA(2) inhibitor arachidonyl trifluoromethyl ketone (AACOCF(3)), and restored by addition of ArAc. Ang II- or ArAc-induced phosphorylation of the EGFR and MAPK were abolished by the EGFR kinase inhibitor AG1478. Ang II or ArAc also stimulated VSMC growth that was blocked by AG1478 or the MAPK kinase (MEK) inhibitor PD98059. Thus, it appears that the cPLA(2)-dependent release of ArAc may provide a mechanism for the transactivation between the AT(1) receptor and the EGFR signaling cascade.

Biocompatible, Biodegradable and Porous Liquid Crystal Elastomer Scaffolds for Spatial Cell Cultures

Macromolecular Bioscience. Feb, 2015  |  Pubmed ID: 25303674

Here we report on the modular synthesis and characterization of biodegradable, controlled porous, liquid crystal elastomers (LCE) and their use as three-dimensional cell culture scaffolds. The elastomers were prepared by cross-linking of star block-co-polymers with pendant cholesterol units resulting in the formation of smectic-A LCEs as determined by polarized optical microscopy, DSC, and X-ray diffraction. Scanning electron microscopy revealed the porosity of the as-prepared biocompatible LCEs, making them suitable as 3D cell culture scaffolds. Biodegradability studies in physiological buffers at varying pH show that these scaffolds are intact for about 11 weeks after which degradation sets in at an exponential rate. Initial results from cell culture studies indicate that these smectic LCEs are compatible with growth, survival, and expansion of cultured neuroblastomas and myoblasts when grown on the LCEs for extended time periods (about a month). These preliminary cell studies focused on characterizing the elastomer-based scaffolds' biocompatibility and the successful 3D incorporation as well as growth of cells in 60 to 150-μm thick elastomer sheets.

Liquid Crystal Elastomer Microspheres As Three-Dimensional Cell Scaffolds Supporting the Attachment and Proliferation of Myoblasts

ACS Applied Materials & Interfaces. Jul, 2015  |  Pubmed ID: 26075811

We report that liquid crystal elastomers (LCEs), often portrayed as artificial muscles, serve as scaffolds for skeletal muscle cell. A simultaneous microemulsion photopolymerization and cross-linking results in nematic LCE microspheres 10-30 μm in diameter that when conjoined form a LCE construct that serves as the first proof-of-concept for responsive LCE muscle cell scaffolds. Confocal microscopy experiments clearly established that LCEs with a globular, porous morphology permit both attachment and proliferation of C2C12 myoblasts, while the nonporous elastomer morphology, prepared in the absence of a microemulsion, does not. In addition, cytotoxicity and proliferation assays confirm that the liquid crystal elastomer materials are biocompatible promoting cellular proliferation without any inherent cytotoxicity.

Effects of Structural Variations on the Cellular Response and Mechanical Properties of Biocompatible, Biodegradable, and Porous Smectic Liquid Crystal Elastomers

Macromolecular Bioscience. Nov, 2016  |  Pubmed ID: 27805765

The authors report on series of side-chain smectic liquid crystal elastomer (LCE) cell scaffolds based on star block-copolymers featuring 3-arm, 4-arm, and 6-arm central nodes. A particular focus of these studies is placed on the mechanical properties of these LCEs and their impact on cell response. The introduction of diverse central nodes allows to alter and custom-modify the mechanical properties of LCE scaffolds to values on the same order of magnitude of various tissues of interest. In addition, it is continued to vary the position of the LC pendant group. The central node and the position of cholesterol pendants in the backbone of ε-CL blocks (alpha and gamma series) affect the mechanical properties as well as cell proliferation and particularly cell alignment. Cell directionality tests are presented demonstrating that several LCE scaffolds show cell attachment, proliferation, narrow orientational dispersion of cells, and highly anisotropic cell growth on the as-synthesized LCE materials.

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