Publications by authors named "Laura J Wood"

29 Publications

  • Page 1 of 1

Clinical applications of microperimetry in RPGR-related retinitis pigmentosa: a review.

Acta Ophthalmol 2021 Mar 29. Epub 2021 Mar 29.

Oxford Eye Hospital, Oxford University Hospitals NHS Trust, Oxford, UK.

Microperimetry, or fundus-tracked perimetry, is a precise static-automated perimetric technique to assess central retinal function. As visual acuity only deteriorates at a late disease stage in RPGR-related retinitis pigmentosa (RP), alternative markers for disease progression are of great utility. Microperimetry assessment has been of critical value as an outcome measure in a recently reported phase I/II gene therapy trial for RPGR-related RP, both in terms of detecting safety and efficacy signals. Here, we performed a review of the literature. We describe the principles of microperimetry before outlining specific parameters that may be useful as outcome measures in clinical trial settings. The current state of structure-function correlations between short-wavelength autofluorescence, optical coherence tomography and adaptive optics in RPGR-related retinitis pigmentosa are also summarized.
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http://dx.doi.org/10.1111/aos.14816DOI Listing
March 2021

Low luminance visual acuity as a clinical measure and clinical trial outcome measure: a scoping review.

Ophthalmic Physiol Opt 2021 Mar 6;41(2):213-223. Epub 2021 Jan 6.

Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.

Purpose: The measurement of standard visual acuity (VA) is the most well-known part of any ophthalmic examination to indicate visual function. Despite this, it is insensitive in detecting early disease changes. Therefore, other visual function tests have been developed including low luminance VA (LLVA) and low luminance deficit (LLD). This scoping literature review aims to summarise the current published applications of LLVA and LLD assessments to evaluate their utility as clinical markers and research outcome measures in a variety of ophthalmic conditions.

Recent Findings: Sixty-five peer-reviewed publications were included. LLVA was pioneered for use in geographic atrophy, a subtype of age-related macular degeneration, which remains the mainstay of its clinical application. However, other studies have reported additional useful applications in inherited retinal diseases including rare maculopathies and rod-cone dystrophies. Although there are some variations in testing methodology, use of the standard Early Treatment Diabetic Retinopathy Study (ETDRS) chart with a 2.0 log unit neutral density filter is the most popular approach. The optimal testing luminance is still to be defined.

Summary: Overall, LLVA is an earlier clinical marker of change in central retinal function than standard VA. It has been shown to be a risk factor for disease progression and a better indicator of a patient's level of everyday visual function. It is inexpensive and simple to implement using readily available standard ophthalmic equipment.
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http://dx.doi.org/10.1111/opo.12775DOI Listing
March 2021

Implementing a human factors approach to RCA : Tools, processes and strategies.

J Healthc Risk Manag 2020 Dec 19. Epub 2020 Dec 19.

Department of Human Factors and Behavioral Neurobiology, Embry-Riddle Aeronautical University, Daytona Beach, FL, 32115, USA.

Root Cause Analysis and Action (RCA ) guidelines offer fundamental improvements to traditional RCA. Yet, these guidelines lack robust methods to support a human factors analysis of patient harm events and development of systems-level interventions. We recently integrated a complement of human factors tools into the RCA process to address this gap. These tools include the Human Factors Analysis and Classification System (HFACS), the Human Factors Intervention Matrix (HFIX), and a multiple-criterion decision tool called FACES, for selecting effective HFIX solutions. We describe each of these tools and illustrate how they can be integrated into RCA to create a robust human factors RCA process called HFACS-RCA . We also present qualitative results from an 18-month implementation study within a large academic health center. Results demonstrate how HFACS-RCA can foster a more comprehensive, human factors analysis of serious patient harm events and the identification of broader system interventions. Following HFACS-RCA implementation, RCA team members (risk managers and quality improvement advisors) also experienced greater satisfaction in their work, leadership gained more trust in RCA findings and recommendations, and the transparency of the RCA process increased. Effective strategies for overcoming implementation barriers, including changes in roles, responsibilities and workload will also be presented.
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http://dx.doi.org/10.1002/jhrm.21454DOI Listing
December 2020

Binocular Visual Function in a Pre-Presbyopic Patient with Uniocular Cataract Undergoing Cataract Surgery with a Multifocal Intraocular Lens.

Clin Ophthalmol 2020 16;14:2001-2009. Epub 2020 Jul 16.

Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.

Background/aim: An increasing number of pre-presbyopic patients are undergoing uniocular cataract extraction. We aim to compare the binocular status of subjects with uniocular cataracts, implanted either with a multifocal or a monofocal intraocular lens (IOL).

Materials And Methods: Subjects were recruited from outpatient ophthalmology clinics and randomized to an IOL type. Corrected and uncorrected LogMAR distance visual acuity (VA) and near and intermediate VA using the Radner reading test were completed. The binocular tests included the Worth Four Dot Test, fixation disparity, TNO stereoacuity and foveal suppression assessment. In addition to the near activity vision questionnaire. The trial was closed early because the chosen multifocal lens had been superseded by newer models. We report two subjects, one receiving the multifocal IOL and a monofocal IOL control with the most comparable baseline characteristics.

Results: Both subjects experienced uncomplicated cataract surgery, showing clinically significant improved corrected distance VA, 0.06 LogMAR and -0.16 LogMAR in the monofocal and multifocal IOL, respectively. The multifocal subject had 30 seconds of arc stereoacuity indicating normal binocular vision. Only gross binocular single vision with no stereopsis was found in the monofocal IOL subject. The latter subject also had reduced near vision quality-of-life questionnaire results.

Conclusion: This two-patient case series demonstrates greater binocular near ability, with the multifocal IOL, in the pre-presbyopic patient undergoing uniocular cataract surgery. The case series highlights the need, and methodology for investigating further the functional and quality-of-life benefits of implanting multifocal IOLs in pre-presbyopic patients, those in their twenties and thirties, undergoing uniocular cataract surgery.
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http://dx.doi.org/10.2147/OPTH.S254532DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7371563PMC
July 2020

A nontargeted approach to determine the authenticity of Ginkgo biloba L. plant materials and dried leaf extracts by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and chemometrics.

Anal Bioanal Chem 2020 Oct 5;412(25):6969-6982. Epub 2020 Aug 5.

National Institute of Metrology, Quality and Technology (INMETRO), Xerém, Duque de Caxias, RJ, 25250-020, Brazil.

The lack of stringent regulations regarding raw materials for herbal supplements used for medicinal purposes has been a constant challenge in the industry. Ginkgo biloba L. leaf extracts attract consumers because of the supposed positive effect on mental performance and memory. Supplements are produced using dried leaf materials and standardized leaf extracts such as EGb 761. Adulteration of Ginkgo biloba L. plants and extracts are becoming more and more common practice due to economically driven motivation from increasing demand in the market and the high cost of raw materials and production. Reinforcement in quality control (QC) to avoid adulterations is necessary to ensure the efficacy of the supplements. In this study, liquid chromatography-high-resolution mass spectrometry (LC-HRMS) was used with principal component analysis (PCA) as an unsupervised exploratory method to analyze, identify, and evaluate the adulterated Ginkgo biloba L. plant materials and dried leaf extracts using the PCA scores and loadings obtained and compound identification.
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http://dx.doi.org/10.1007/s00216-020-02830-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953348PMC
October 2020

Beyond the corrective action hierarchy: A systems approach to organizational change.

Int J Qual Health Care 2020 Sep;32(7):438-444

Department of Industrial and Systems Engineering, University of Wisconsin-Madison, 1513 University Ave, Madison, WI 53706 USA.

Background: Many patient safety organizations recommend the use of the action hierarchy (AH) to identify strong corrective actions following an investigative analysis of patient harm events. Strong corrective actions, such as forcing functions and equipment standardization, improve patient safety by either preventing the occurrence of active failures (i.e. errors or violations) or reducing their consequences if they do occur.

Problem: We propose that the emphasis on implementing strong fixes that incrementally improve safety one event at a time is necessary, yet insufficient, for improving safety. This singular focus has detracted from the pursuit of major changes that transform systems safety by targeting the latent conditions which consistently underlie active failures. To date, however, there are no standardized models or methods that enable patient safety professionals to assess, develop and implement systems changes to improve patient safety.

Approach: We propose a multifaceted definition of 'systems change'. Based on this definition, various types and levels of systems change are described. A rubric for determining the extent to which a specific corrective action reflects a 'systems change' is provided. This rubric incorporates four fundamental dimensions of systems change: scope, breadth, depth and degree. Scores along these dimensions can then be used to classify corrective actions within our proposed systems change hierarchy (SCH).

Conclusion: Additional research is needed to validate the proposed rubric and SCH. However, when used in conjunction with the AH, the SCH perspective will serve to foster a more holistic and transformative approach to patient safety.
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http://dx.doi.org/10.1093/intqhc/mzaa068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7654382PMC
September 2020

Low-contrast visual acuity versus low-luminance visual acuity in choroideremia.

Clin Exp Optom 2021 Jan;104(1):90-94

Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford , Oxford, UK.

Clinical Relevance: Choroideremia is a progressive X-linked inherited rod-cone dystrophy. Patients present with nyctalopia and progressive visual field loss, but visual acuity remains well preserved early on. This study showed that low-luminance visual acuity may be a useful clinical outcome measure during earlier disease stages.

Background: Choroideremia is a progressive X-linked inherited rod-cone dystrophy. Patients present with nyctalopia and progressive visual field loss. However, visual acuity remains well preserved until late in the disease process, limiting its usefulness as a clinical trial endpoint across the disease spectrum. Visual acuity measurements under low-luminance and low-contrast conditions may be affected sooner and have been suggested as early markers in other ocular diseases. This study assesses whether low-luminance visual acuity and low-contrast visual acuity provide useful endpoints in choroideremia clinical trials.

Method: Standard high-contrast and low-luminance visual acuity was obtained on 29 choroideremia subjects and 16 healthy controls, using a logMAR chart, set at four metres. Low-luminance visual acuity was tested using a 2.0-log unit neutral density filter, with the same chart set-up, without formal dark adaptation. This was followed by low-contrast visual acuity measured using 1.25 per cent and 2.5 per cent low-contrast logMAR charts placed also at four metres. Data from the right eyes only were analysed using non-parametric statistics. High-contrast visual acuity minus low-luminance and low-contrast visual acuity provided the low-luminance and low-contrast difference scores.

Results: A higher number of choroideremia subjects were able to complete the low-luminance test than the low-contrast visual acuity tests. Choroideremia subjects had significantly higher low luminance, 2.5 per cent low-contrast and 1.25 per cent low-contrast difference scores compared with controls (p < 0.01, Mann-Whitney U-test); 1.25 per cent low-contrast visual acuity revealed the poorest performance. A strong positive correlation was found between low-luminance and high-contrast visual acuities (ρ = 0.818, p < 0.001) and 2.5 per cent low-contrast and high-contrast visual acuities (ρ = 0.671, p < 0.001).

Conclusion: The low-luminance visual acuity test may be a useful additional clinical trial outcome measure for early-to-moderate disease, when high-contrast visual acuity is preserved.
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http://dx.doi.org/10.1111/cxo.13087DOI Listing
January 2021

Test-retest repeatability of microperimetry in patients with retinitis pigmentosa caused by mutations in RPGR.

Clin Exp Ophthalmol 2020 07 27;48(5):714-715. Epub 2020 Apr 27.

Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.

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http://dx.doi.org/10.1111/ceo.13753DOI Listing
July 2020

Initial results from a first-in-human gene therapy trial on X-linked retinitis pigmentosa caused by mutations in RPGR.

Nat Med 2020 03 24;26(3):354-359. Epub 2020 Feb 24.

Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK.

Retinal gene therapy has shown great promise in treating retinitis pigmentosa (RP), a primary photoreceptor degeneration that leads to severe sight loss in young people. In the present study, we report the first-in-human phase 1/2, dose-escalation clinical trial for X-linked RP caused by mutations in the RP GTPase regulator (RPGR) gene in 18 patients over up to 6 months of follow-up (https://clinicaltrials.gov/: NCT03116113). The primary outcome of the study was safety, and secondary outcomes included visual acuity, microperimetry and central retinal thickness. Apart from steroid-responsive subretinal inflammation in patients at the higher doses, there were no notable safety concerns after subretinal delivery of an adeno-associated viral vector encoding codon-optimized human RPGR (AAV8-coRPGR), meeting the pre-specified primary endpoint. Visual field improvements beginning at 1 month and maintained to the last point of follow-up were observed in six patients.
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http://dx.doi.org/10.1038/s41591-020-0763-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7104347PMC
March 2020

Challenges in Developing Analytically Validated Laboratory-Derived Dietary Supplement Databases.

J Nutr 2018 08;148(suppl_2):1406S-1412S

Nutrient Data Laboratory, Agricultural Research Service, US Department of Agriculture, Beltsville, MD.

The Dietary Supplement Label Database (DSLD) is sponsored by the Office of Dietary Supplements (ODS) and the National Library of Medicine (NLM). It provides a searchable, free database of the contents of ∼65,000 supplement labels. A companion database of analytically verified product labels [the Dietary Supplement Ingredient Database (DSID)] was created by ODS, NLM, and the USDA. There are considerable challenges to populating both databases, but the DSID faces unique analytic chemistry challenges. This article describes the challenges to creating analytically verified marketplace surveys of dietary supplement (DS) product content claims for inclusion in public databases. Nutritionists and public health scientists require information on actual exposures to DS constituents because labeled content may not match labeled product content. Analytic verification of composition of DSs provides a link to actual exposure. A public database of analytically derived DS content was developed to provide more accurate estimates of dietary intake in population-based epidemiologic studies. The DSID has conducted surveys of several types of vitamin- and mineral-containing DSs. Results showing label content claims as analytically derived values are available in the current DSID. A recent pilot project explored the feasibility of adding botanical DS products to the DSID. Candidates for future botanical DSID studies will be based on sales volume, potential public health impacts, and the availability of validated analytic methods and reference materials. Databases like DSID and the DSLD are essential for researchers and clinicians to evaluate dietary ingredient intakes in population-based epidemiologic studies. Together, these databases provide a picture of the DS marketplace. The DSID provides an analytic survey of marketed DSs. However, selection of future botanical supplements for DSID evaluation involves analytic challenges. Even when appropriate resources are available, method selection and data evaluation are resource- and time-consuming.
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http://dx.doi.org/10.1093/jn/nxy134DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6857616PMC
August 2018

Competency-based Professional Advancement Model for Advanced Practice RNs.

J Nurs Adm 2019 Feb;49(2):66-72

Author Affiliations: Nurse Practitioner (Dr Paul), Center for Motility and Functional Gastrointestinal Disorders; Clinical Nurse Specialist (Ms Abecassis), Medical Intensive Care; Clinical Nurse Specialist (Ms Freiberger), Pulmonary/Pediatric Transplant Center; Clinical Nurse Specialist (Ms Hamilton), Medical Surgical Intensive Care; Nurse Practitioner (Ms Kelly), Urology and Urodynamics; Clinical Nurse Specialist (Ms Klements), Asthma and Medicine Patient Services; Nurse Practitioner (Dr LaGrasta), Cardiovascular Surgical Services; Nurse Practitioner (Mss Lemire, O'Donnell, and Phinney), General Surgery; Nurse Practitioner (Ms Patisteas), Orthopedic Surgery; Professional Development Specialist (Ms Conwell), Clinical Education and Informatics; Nurse Practitioner (Dr Saia), Cardiology; Nurse Practitioner (Ms Whelan), Cardiac Intensive Care; Senior VP, Patient Care Operations and Chief Nursing Officer (Dr Wood); and Nurse Practitioner (Ms O'Brien), Cardiology: Boston Children's Hospital, Massachusetts.

The process of developing a 3-tiered advanced practice RN (APRN) competency-based professional advancement model at Boston Children's Hospital is described. The model recognizes the contributions of entry-level and expert APRNs to advanced clinical practice and outcomes, impact, and leadership, while incorporating the tenets of Patricia Benner's Novice to Expert Model and the American Association of Critical- Care Nurses Synergy Model of Care.
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http://dx.doi.org/10.1097/NNA.0000000000000719DOI Listing
February 2019

Development of a kelp powder (Thallus laminariae) Standard Reference Material.

Anal Bioanal Chem 2018 Feb 9;410(4):1265-1278. Epub 2017 Dec 9.

Chemical Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA.

A Standard Reference Material (SRM) of seaweed, SRM 3232 Kelp Powder (Thallus laminariae) has been developed to support food and dietary supplement measurements in compliance with the Food Safety Modernization Act (FSMA) and the Dietary Supplement Health and Education Act of 1994 (DSHEA). The material was characterized for nutritional minerals, arsenic species, isomers of vitamin K, proximates, and toxic elements. Kelp is a rich source of vitamins and minerals, and it is an excellent source of dietary iodine. Kelp also contains a large amount of arsenic, which is toxic as inorganic species but much less so as organic species. To capture the dietary profile of kelp, certified values were issued for As, Ca, Cd, Cr, Cu, Fe, Hg, I, K, Mg, Mn, Mo, Na, Pb, and Zn. Reference values for proximates were assigned. For the first time, a certified value for iodine, reference values for isomers of vitamin K, and reference values for arsenic species including arsenosugars were assigned in a seaweed. SRM 3232 fills a gap in Certified Reference Materials (CRMs) needed for quality assurance and method validation in the compositional measurements of kelp and similar seaweeds used as food and as dietary supplements. Graphical Absract Arsenic species and isomers of vitamin K were determined in the development of SRM 3232 Kelp Powder (Thallus laminariae).
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http://dx.doi.org/10.1007/s00216-017-0766-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6013078PMC
February 2018

Development of a Cigarette Tobacco Filler Standard Reference Material.

Anal Chem 2017 10 20;89(19):10461-10467. Epub 2017 Sep 20.

Centers for Disease Control and Prevention , Tobacco Products Laboratory, 4770 Buford Highway, Atlanta, Georgia 30341, United States.

A new tobacco filler Standard Reference Material (SRM) has been issued by the National Institute of Standards and Technology (NIST) in September 2016 with certified and reference mass fraction values for nicotine, N-nitrosonornicotine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, and volatiles. The constituents have been determined by multiple analytical methods with measurements at NIST and at the Centers for Disease Control and Prevention, and with confirmatory measurements by commercial laboratories. This effort highlights the development of the first SRM for reduced nicotine and reduced tobacco-specific nitrosamines with certified values for composition.
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http://dx.doi.org/10.1021/acs.analchem.7b02550DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5687819PMC
October 2017

Commonalities of nurse-designed models of health care.

Nurs Outlook 2015 Sep-Oct;63(5):540-53. Epub 2015 May 4.

Boston Children's Hospital, Boston, MA.

The American Academy of Nursing has identified examples of care redesign developed by nurses who address the health needs of diverse populations. These models show important clinical and financial outcomes as summarized in the Select Edge Runner Models of Care table included in this article. A study team appointed by the Academy explored the commonalities across these models. Four commonalities emerged: health holistically defined; individual-, family-, and community-centric approaches to care; relationship-based care that enables partnerships and builds patient engagement and activation; and a shift from episodic individual care to continuous group and public health approaches. The policy implications include examining measures of an expanded definition of health, paying for visionary care, and transparency and rewards for community-level engagement.
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http://dx.doi.org/10.1016/j.outlook.2015.04.009DOI Listing
May 2016

Certification of elements in and use of standard reference material 3280 multivitamin/multielement tablets.

J AOAC Int 2013 Nov-Dec;96(6):1281-7

Standard Reference Material 3280 Multivitamin/ Multielement Tablets was issued by the National Institute of Standards and Technology in 2009, and has certified and reference mass fraction values for 13 vitamins, 26 elements, and two carotenoids. Elements were measured using two or more analytical methods at NIST with additional data contributed by collaborating laboratories. This reference material is expected to serve a dual purpose: to provide quality assurance in support of a database of dietary supplement products and to provide a means for analysts, dietary supplement manufacturers, and researchers to assess the appropriateness and validity of their analytical methods and the accuracy of their results.
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http://dx.doi.org/10.5740/jaoacint.13-135DOI Listing
April 2014

Development of a Standard Reference Material for metabolomics research.

Anal Chem 2013 Dec 3;85(24):11732-8. Epub 2013 Dec 3.

Biomolecular Measurement Division, #Chemical Sciences Division, and □Biosystems and Biomaterials Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH), has developed a Standard Reference Material (SRM) to support technology development in metabolomics research. SRM 1950 Metabolites in Human Plasma is intended to have metabolite concentrations that are representative of those found in adult human plasma. The plasma used in the preparation of SRM 1950 was collected from both male and female donors, and donor ethnicity targets were selected based upon the ethnic makeup of the U.S. population. Metabolomics research is diverse in terms of both instrumentation and scientific goals. This SRM was designed to apply broadly to the field, not toward specific applications. Therefore, concentrations of approximately 100 analytes, including amino acids, fatty acids, trace elements, vitamins, hormones, selenoproteins, clinical markers, and perfluorinated compounds (PFCs), were determined. Value assignment measurements were performed by NIST and the Centers for Disease Control and Prevention (CDC). SRM 1950 is the first reference material developed specifically for metabolomics research.
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http://dx.doi.org/10.1021/ac402689tDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4823010PMC
December 2013

Breakfast cereal sampling study for nutritional elements.

Anal Bioanal Chem 2013 May 5;405(13):4569-78. Epub 2013 Feb 5.

National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.

The National Institute of Standards and Technology (NIST) has established a Dietary Supplement Laboratory Quality Assurance Program (DSQAP) in collaboration with the National Institutes of Health Office of Dietary Supplements (NIH-ODS). The DSQAP invites laboratories twice annually to participate in interlaboratory studies where participants elect to measure concentrations of nutritional and/or toxic elements as well as active and/or marker compounds. One of these studies was designed to determine the effects of material granularity and sample processing techniques on measurement variability (precision) as well as to provide participating laboratories information on their performance relative to the NIST assigned values (bias) and to the other participants (concordance). Participants were asked to determine the mass fractions of Ca, Fe, and Zn, in mg/kg, in six breakfast cereal samples. Cereal samples consisted of three ground materials (homogenized wheat, wheat, and rice), two flake materials (wheat and rice) and a partially crushed material (a wheat/rice mixture). In general, approximately 25% of the laboratories processed and analyzed the suite of six cereal materials with adequate to exemplary measurement precision. Over half of the laboratories (60%) experienced measurement issues related to only a particular type of cereal matrix or for only a single element. A small number (15%) of laboratories experienced significant sample processing or measurement problems. Future studies planned by the DSQAP may be designed to use commercial products to aid laboratories with their sampling and analytical techniques.
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http://dx.doi.org/10.1007/s00216-013-6727-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3719853PMC
May 2013

Dietary supplement laboratory quality assurance program: the first five exercises.

J AOAC Int 2011 May-Jun;94(3):803-14

National Institute of Standards and Technology, Analytical Chemistry Division, Material Measurement Laboratory, Gaithersburg, MD 20899-8392, USA.

The National Institute of Standards and Technology (NIST) has established a Dietary Supplement Laboratory Quality Assurance Program (DSQAP) in collaboration with the National Institutes of Health Office of Dietary Supplements. Program participants measure concentrations of active and/or marker compounds as well as nutritional and toxic elements in food and dietary supplements distributed by NIST. Data are compiled at NIST, where they are analyzed for accuracy relative to reference values and concordance among the participants. Performance reports and certificates of completion are provided to participants, which can be used to demonstrate compliance with current Good Manufacturing Practices as promulgated by the U.S. Food and Drug Administration. The DSQAP has conducted five exercises to date, with total participation including more than 75 different laboratories and many more individual analysts.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3173719PMC
August 2011

Characterization of three berry standard reference materials for nutrients.

J Agric Food Chem 2011 Jul 20;59(13):7246-52. Epub 2011 Jun 20.

National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.

The National Institute of Standards and Technology (NIST) has been working with the National Institutes of Health Office of Dietary Supplements to produce Standard Reference Materials (SRMs) of interest to analysts of dietary supplements. Some of these SRMs are traditional foods including SRM 3281 Cranberry (Fruit), SRM 3282 Low-Calorie Cranberry Juice Cocktail, and SRM 3287 Blueberry (Fruit), which have been characterized for nine nutritional elements and sugars. The blueberries have also been characterized for proximates, two water-soluble vitamins, and amino acids. These new materials are intended for use in method development and validation as well as for quality assurance and traceability in the assignment of values to in-house control materials. Foods can be difficult to analyze because of matrix effects. With the addition of these three new SRMs, it is now possible to more closely match controls to matrices and analyte levels for fruit and vegetable test samples. Several nutritional elements in these three SRMs are present at lower levels than in other food-matrix SRMs.
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http://dx.doi.org/10.1021/jf200883eDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3153887PMC
July 2011

Preparation and characterization of standard reference material 1849 infant/adult nutritional formula.

J AOAC Int 2010 Jul-Aug;93(4):1262-74

National Institute of Standards and Technology, Analytical Chemistry Division, Gaithersburg, MD 20899-8390, USA.

Standard Reference Material (SRM) 1849 Infant/Adult Nutritional Formula has been issued by the National Institute of Standards and Technology (NIST) as a replacement for SRM 1846 Infant Formula, issued in 1996. Extraction characteristics of SRM 1846 have changed over time, as have NIST's analytical capabilities. While certified mass fraction values were provided for five constituents in SRM 1846 (four vitamins plus iodine), certified mass fraction values for 43 constituents are provided in SRM 1849 (fatty acids, elements, and vitamins) and reference mass fraction values are provided for an additional 43 constituents including amino acids and nucleotides, making it the most extensively characterized food-matrix SRM available from NIST.
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October 2010

Translational considerations for cancer nanomedicine.

J Control Release 2010 Sep 10;146(2):164-74. Epub 2010 Apr 10.

Nanotechnology Characterization Laboratory, Advanced Technology Program, SAIC-Frederick Inc., NCI-Frederick, PO Box B, Frederick, MD 21702, USA.

There are many important considerations during preclinical development of cancer nanomedicines, including: 1) unique aspects of animal study design; 2) the difficulties in evaluating biological potency, especially for complex formulations; 3) the importance of analytical methods that can determine platform stability in vivo, and differentiate bound and free active pharmaceutical ingredient (API) in biological matrices; and 4) the appropriateness of current dose scaling techniques for estimation of clinical first-in-man dose from preclinical data. Biologics share many commonalities with nanotechnology products with regard to complexity and biological attributes, and can, in some cases, provide context for dealing with these preclinical issues. In other instances, such as the case of in vivo stability analysis, new approaches are required. This paper will discuss the significance of these preclinical issues, and present examples of current methods and best practices for addressing them. Where possible, these recommendations are justified using the existing regulatory guidance literature.
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http://dx.doi.org/10.1016/j.jconrel.2010.04.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2921639PMC
September 2010

Maternal depression: the cost of caring for a child with intractable epilepsy.

Pediatr Neurol 2008 Dec;39(6):418-22

Faculty of Medicine, University of Alberta, Edmonton, Alberta, Canada.

The aims of this study were to: (1) determine the prevalence of depression and sleep disruption in mothers of children with intractable epilepsy, and (2) assess which family factors and neurologic/behavioral characteristics of a child with epilepsy correlate with maternal depression. Mothers of children aged 2-18 years with intractable epilepsy completed a Beck Depression Inventory and Pittsburgh Sleep Questionnaire for themselves, and a Child Behavior Checklist, Attention Deficit Hyperactivity Disorder Rating Scale, and Scale of Independent Behavior-Revised for their child. Charts were reviewed for age at seizure onset, seizure frequency and type, number of failed treatments, and presence of autism. Mothers were queried regarding family type, educational level, income, and number of children in the home. Fifty-two of 80 (65%) eligible mothers returned completed questionnaires. Forty-five percent demonstrated elevated scores on the depression questionnaire, with 25% in the moderate/severely depressed range. Sleep disruption was reported in 67%. Maternal depression correlated with high attention deficit and problem behaviors in children, but not with most epilepsy-related variables, autism, adaptive delay, or family income.
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http://dx.doi.org/10.1016/j.pediatrneurol.2008.08.007DOI Listing
December 2008

Development of saw palmetto (Serenoa repens) fruit and extract standard reference materials.

Anal Bioanal Chem 2008 Oct 2;392(3):427-38. Epub 2008 Aug 2.

Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.

As part of a collaboration with the National Institutes of Health's Office of Dietary Supplements and the Food and Drug Administration's Center for Drug Evaluation and Research, the National Institute of Standards and Technology has developed two standard reference materials (SRMs) representing different forms of saw palmetto (Serenoa repens), SRM 3250 Serenoa repens fruit and SRM 3251 Serenoa repens extract. Both of these SRMs have been characterized for their fatty acid and phytosterol content. The fatty acid concentration values are based on results from gas chromatography with flame ionization detection (GC-FID) and mass spectrometry (GC/MS) analysis while the sterol concentration values are based on results from GC-FID and liquid chromatography with mass spectrometry analysis. In addition, SRM 3250 has been characterized for lead content, and SRM 3251 has been characterized for the content of beta-carotene and tocopherols. SRM 3250 (fruit) has certified concentration values for three phytosterols, 14 fatty acids as triglycerides, and lead along with reference concentration values for four fatty acids as triglycerides and 16 free fatty acids. SRM 3251 (extract) has certified concentration values for three phytosterols, 17 fatty acids as triglycerides, beta-carotene, and gamma-tocopherol along with reference concentration values for three fatty acids as triglycerides, 17 fatty acids as free fatty acids, beta-carotene isomers, and delta-tocopherol and information values for two phytosterols. These SRMs will complement other reference materials currently available with concentrations for similar analytes and are part of a series of SRMs being developed for dietary supplements.
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http://dx.doi.org/10.1007/s00216-008-2297-0DOI Listing
October 2008

Depression, anxiety, and quality of life in siblings of children with intractable epilepsy.

Epilepsy Behav 2008 Jul 5;13(1):144-8. Epub 2008 May 5.

University of Alberta, Edmonton, AB, Canada.

Thirty-seven siblings (aged 6-18) of children with intractable epilepsy were surveyed regarding their anxiety, depression, and quality of life, by both self-report (Revised Children's Manifest Anxiety Scale, RCMAS; Children's Depression Inventory, CDI; and Peds QL) and parental report (Child Behavior Checklist, CBCL). Completed forms were returned by 37 of 58 (64%) eligible families. No sibling had a score in the clinical range on the CDI, and only 2 of 37 (6%) scored in the clinical range on the RCMAS, a proportion similar to the normative population. In contrast, 25% were rated by their parents to have elevated Internalizing Behaviors scores on the CBCL. There was a trend for PedsQL scores to be lower than the normative mean. Comorbid behavior and attention problems in the child with epilepsy and sibling CDI and RCMAS scores correlated significantly with self-reported quality of life. However, other epilepsy, child, and family variables (income, parental education, family function, maternal depression) did not correlate. We conclude that siblings of children with intractable epilepsy are functioning well overall and have a good quality of life.
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http://dx.doi.org/10.1016/j.yebeh.2008.03.012DOI Listing
July 2008

Characterization of a suite of ginkgo-containing standard reference materials.

Anal Bioanal Chem 2007 Sep 7;389(1):179-96. Epub 2007 Jul 7.

National Institute of Standards and Technology, Gaithersburg, MD 20899-8392, USA.

A suite of three ginkgo-containing dietary supplement Standard Reference Materials (SRMs) has been issued by the National Institute of Standards and Technology (NIST) with certified values for flavonoid aglycones, ginkgolides, bilobalide, and selected toxic trace elements. The materials represent a range of matrices (i.e., plant, extract, and finished product) that provide different analytical challenges. The constituents have been determined by at least two independent analytical methods with measurements performed by NIST and at least one collaborating laboratory. The methods utilized different extractions, chromatographic separations, modes of detection, and approaches to quantitation. The SRMs are primarily intended for method validation and for use as control materials to support the analysis of dietary supplements and related botanical materials.
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http://dx.doi.org/10.1007/s00216-007-1398-5DOI Listing
September 2007

Preparation and characterization of a suite of ephedra-containing standard reference materials.

J AOAC Int 2006 Nov-Dec;89(6):1483-95

National Institute of Standards and Technology, Analytical Chemistry Division, Gaithersburg, MD 20899-8390, USA.

The National Institute of Standards and Technology, the U.S. Food and Drug Administration, Center for Drug Evaluation and Research and Center for Food Safety and Applied Nutrition, and the National Institutes of Health, Office of Dietary Supplements, are collaborating to produce a series of Standard Reference Materials (SRMs) for dietary supplements. A suite of ephedra materials is the first in the series, and this paper describes the acquisition, preparation, and value assignment of these materials: SRMs 3240 Ephedra sinica Stapf Aerial Parts, 3241 E. sinica Stapf Native Extract, 3242 E. sinica Stapf Commercial Extract, 3243 Ephedra-Containing Solid Oral Dosage Form, and 3244 Ephedra-Containing Protein Powder. Values are assigned for ephedrine alkaloids and toxic elements in all 5 materials. Values are assigned for other analytes (e.g., caffeine, nutrient elements, proximates, etc.) in some of the materials, as appropriate. Materials in this suite of SRMs are intended for use as primary control materials when values are assigned to in-house (secondary) control materials and for validation of analytical methods for the measurement of alkaloids, toxic elements, and, in the case of SRM 3244, nutrients in similar materials.
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February 2007

Determination of cyanide in blood by isotope-dilution gas chromatography-mass spectrometry.

Clin Chem 2006 Mar 26;52(3):458-67. Epub 2006 Jan 26.

National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.

Background: Cyanide (CN) is a lethal toxin. Quantification in blood is necessary to indicate exposure from many sources, including food, combustion byproducts, and terrorist activity. We describe an automated procedure based on isotope-dilution gas chromatography-mass spectrometry (ID GC/MS) for the accurate and rapid determination of CN in whole blood.

Methods: A known amount of isotopically labeled potassium cyanide (K13C15N) was added to 0.5 g of whole blood in a headspace vial. Hydrogen cyanide was generated through the addition of phosphoric acid, and after a 5-min incubation, 0.5 mL of the headspace was injected into the GC/MS at an oven temperature of -15 degrees C. The peak areas from the sample, 1H12C14N+, at m/z 27, and the internal standard, 1H13C15N+, at m/z 29, were measured, and the CN concentration was quantified by ID. The analysis time was 15 min for a single injection.

Results: We demonstrated method accuracy by measuring the CN content of unfrozen whole blood samples fortified with a known amount of CN. Intermediate precision was demonstrated by periodic analyses over a 14-month span. Relative expanded uncertainties based on a 95% level of confidence with a coverage factor of 2 at CN concentrations of 0.06, 0.6, and 1.5 microg/g were 8.3%, 5.4%, and 5.3%, respectively. The mean deviation from the known value for all concentrations was <4%.

Conclusion: The automated ID GC/MS method can accurately and rapidly quantify nanogram per gram to microgram per gram concentrations of CN in blood.
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http://dx.doi.org/10.1373/clinchem.2005.061002DOI Listing
March 2006

Value assignment of nutrient and aflatoxin concentrations in standard reference material 2387 peanut butter.

J Agric Food Chem 2003 Nov;51(23):6745-51

National Institute of Standards and Technology, 100 Bureau Drive Stop 8392, Gaithersburg, Maryland 20899-8392, USA.

Standard Reference Material (SRM) 2387 peanut butter was recently issued, and the process used for value assignment of nutrient and aflatoxin concentrations is reported herein. Values were assigned using data provided by the National Institute of Standards and Technology (NIST) and collaborating laboratories. SRM 2387 is intended for use as a primary material for assigning values to in-house control materials and for validation of analytical methods for measurements in peanut butter and similar high-fat matrixes. SRM 2387 lies in sector 3 of AOAC International's fat-protein-carbohydrate triangle. With the addition of SRM 2387, NIST now offers materials within-or on the borders between-all sectors of the triangle. The Certificate of Analysis for SRM 2387 provides assigned values for concentrations of fatty acids, proximates, elements, and total dietary fiber, for which product labeling is required by the Nutrition Labeling and Education Act of 1990, as well as several vitamins, amino acids, and aflatoxins, for which labeling is not required. (Aflatoxin levels in peanut butter are regulated by the Food and Drug Administration.)
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http://dx.doi.org/10.1021/jf034637oDOI Listing
November 2003

Value assignment of nutrient concentrations in standard reference material 2384 baking chocolate.

J Agric Food Chem 2002 Nov;50(24):7069-75

National Food Processors Association, 1350 I Street NW, Suite 300, Washington, DC 20005, USA.

Standard Reference Material (SRM) Baking Chocolate was recently issued, and the process used for value assignment of nutrient concentrations is reported herein. SRM 2384 is intended for use as a primary control material for assigning values to in-house control materials and for validation of analytical methods for the measurement of fatty acids, proximates, vitamins, and elements in chocolate and similar high-fat matrices. The Certificate of Analysis for SRM 2384 provides assigned values for concentrations of fatty acids, proximates, vitamins, elements, and total dietary fiber, for which product labeling is required by the Nutrition Labeling and Education Act of 1990, as well as for catechins, caffeine, theobromine, and theophylline. These assigned values were based on measurements by NIST and/or collaborating laboratories.
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http://dx.doi.org/10.1021/jf020610dDOI Listing
November 2002