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James F. Griffith

Bio: James F. Griffith is an academic researcher from The Chinese University of Hong Kong. The author has contributed to research in topics: Osteoporosis & Bone mineral. The author has an hindex of 56, co-authored 370 publications receiving 10918 citations. Previous affiliations of James F. Griffith include Coventry Health Care & Queen Elizabeth Hospital Birmingham.


Papers
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Journal ArticleDOI
TL;DR: To use proton magnetic resonance spectroscopy (1H‐MRS) to evaluate vertebral marrow fat, and to determine whether bone density correlates with fat content and fat unsaturation levels in postmenopausal women.
Abstract: Purpose To use proton magnetic resonance spectroscopy (1H-MRS) to evaluate vertebral marrow fat, and to determine whether bone density correlates with fat content and fat unsaturation levels in postmenopausal women. Materials and Methods Fifty-three women (mean age = 70 years) underwent dual energy x-ray absorptiometry and 1H-MRS, and 12 young female controls (mean age = 28 years) underwent 1H-MRS of the lumber spine. Water and lipid peak amplitudes were measured to calculate fat content and fat unsaturation index. Spearman's correlation tests and a t-test comparison of means were applied. Results 1H-MRS was successful in 15 normal, 15 osteopenic, and 20 osteoporotic subjects, and in all controls. Marrow fat content was significantly elevated in osteoporotic (65.5% ± 10%) and osteopenic (63.5% ± 9.3%) subjects compared to normal subjects (56.3% ± 11.2%) and young controls (29% ± 9.6%). The fat unsaturation index was significantly decreased in osteoporotic (0.091 ± 0.013) and osteopenic (0.097 ± 0.014) subjects compared to normal subjects (0.114 ± 0.016) and young controls (0.127 ± 0.031). A good inverse correlation was observed between the fat content and the unsaturation index (rs = −0.53, P < 0.0001). Conclusion Osteoporosis is associated with increased marrow fat. As marrow fat increases, saturated lipids appear to increase preferentially to unsaturated lipids. J. Magn. Reson. Imaging 2005;22:279–285. © 2005 Wiley-Liss, Inc.

406 citations

Journal ArticleDOI
TL;DR: Subjects with osteoporosis have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with osteopenia and subjects with normal bone density.
Abstract: PURPOSE: To prospectively use hydrogen 1 (1H) magnetic resonance (MR) spectroscopy and dynamic contrast material–enhanced MR imaging to measure vertebral body marrow fat content and bone marrow perfusion in older men with varying bone mineral densities as documented with dual x-ray absorptiometry (DXA). MATERIALS AND METHODS: This study had institutional review board approval, and all participants provided informed consent. DXA, 1H MR spectroscopy, and dynamic contrast-enhanced MR imaging of the lumbar spine were performed in 90 men (mean age, 73 years; range, 67–101 years). Vertebral marrow fat content and perfusion (maximum enhancement and enhancement slope) were compared for subject groups with differing bone densities (normal, osteopenic, and osteoporotic). The t test was used for comparisons between groups, and the Pearson test was used to determine correlation between marrow fat content and perfusion indexes. RESULTS: Eight subjects were excluded, yielding a final cohort of 82 subjects (mean age, 73...

386 citations

Journal ArticleDOI
15 Nov 2007-Spine
TL;DR: The modified Pfirrmann grading system is useful at discriminating severity of disc degeneration in elderly subjects and can be applied with good intra- and interobserver agreement.
Abstract: Study design A reliability study was conducted. OBJECTIVE.: To modify a grading system for lumbar disc degeneration and to test the reliability of this modified grading system. Summary of background data The 5-level Pfirrmann grading system for disc degeneration did not prove discriminatory when used to assess disc degeneration in the elderly spine. Such discriminatory power is necessary to test the association between other variables and severity of disc degeneration. Methods An 8-level modified grading system for lumbar disc degeneration was developed including a description of the changes expected for each grade and a 24-image reference panel. The reliability of the modified grading system was tested on 260 lumbar intervertebral discs in 52 subjects (26 men, 26 female) with a mean age of 73 years (range, 67-83 years). All examinations were analyzed independently by 3 readers. Intraobserver and interobserver reliabilities were assessed by calculating weighted kappa statistics. Results On average, for all 3 readers, 0.39% of the 260 discs were classified as Grade 2, 22% were classified as Grade 3, 21.5% were classified as Grade 4, 25.3% were classified as Grade 5, 19.1% were classified as Grade 6, 7.1% were classified as Grade 7, and 4.8% were classified as Grade 8. Intraobserver agreement was excellent (weighted kappa range, 0.79-0.91) with substantial interobserver agreement (weighted kappa range, 0.65-0.67). Complete intraobserver agreement was obtained, on average, in 85% of all discs with 84% of disagreement being as a result of a 1 grade difference. Complete interobserver agreement was obtained, on average, in 66% of all discs with 91% of disagreement being as a result of a 1 grade difference. Conclusion The modified Pfirrmann grading system is useful at discriminating severity of disc degeneration in elderly subjects. The system can be applied with good intra- and interobserver agreement.

367 citations

Journal ArticleDOI
TL;DR: The subjects experienced a decrease in vertebral marrow maximum enhancement and enhancement slope and an increase in marrow fat content as bone density decreased and the reduction in perfusion indexes occurred only within the vertebral body and not in the paravertebral tissues supplied by the same artery.
Abstract: Purpose: To prospectively study the relationship among vertebral marrow fat content, marrow diffusion indexes, and marrow and erector spinae muscle perfusion indexes in female subjects with varying bone mineral density. Materials and Methods: Institutional study approval and informed consent were obtained. Dual x-ray absorptiometry, proton magnetic resonance (MR) spectroscopy, diffusion-weighted MR imaging, and dynamic contrast material–enhanced MR imaging of the lumbar spine and erector spinae muscle were performed in 110 women (mean age, 73 years; range, 67–84 years). Marrow fat content, marrow apparent diffusion coefficient (ADC), and perfusion indexes (maximum enhancement and enhancement slope) of marrow and erector spinae muscle were compared among three bone density groups (normal, osteopenic, and osteoporotic). The t test comparisons and Pearson correlations were applied. Results: Seven subjects were excluded, which yielded a final cohort of 103 subjects: 18 with normal bone density, 30 with osteop...

317 citations

Journal ArticleDOI
TL;DR: In this paper, the authors studied the conductivity of the oxygen-ion conductivity solid electrolyte system CeO2:Y2O3 as a function of temperature and dopant concentration.

313 citations


Cited by
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01 Aug 2000
TL;DR: Assessment of medical technology in the context of commercialization with Bioentrepreneur course, which addresses many issues unique to biomedical products.
Abstract: BIOE 402. Medical Technology Assessment. 2 or 3 hours. Bioentrepreneur course. Assessment of medical technology in the context of commercialization. Objectives, competition, market share, funding, pricing, manufacturing, growth, and intellectual property; many issues unique to biomedical products. Course Information: 2 undergraduate hours. 3 graduate hours. Prerequisite(s): Junior standing or above and consent of the instructor.

4,833 citations

Journal ArticleDOI
01 Jul 2016-Medicine
TL;DR: According to the analysis, old men plus gastric fundus or antrum of CFB were strongly suggested to perform ESD if precancerous lesions were found and young women with low-grade intraepithelial neoplasia could select regular follow-up.

3,491 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe the rules of the ring, the ring population, and the need to get off the ring in order to measure the movement of a cyclic clock.
Abstract: 1980 Preface * 1999 Preface * 1999 Acknowledgements * Introduction * 1 Circular Logic * 2 Phase Singularities (Screwy Results of Circular Logic) * 3 The Rules of the Ring * 4 Ring Populations * 5 Getting Off the Ring * 6 Attracting Cycles and Isochrons * 7 Measuring the Trajectories of a Circadian Clock * 8 Populations of Attractor Cycle Oscillators * 9 Excitable Kinetics and Excitable Media * 10 The Varieties of Phaseless Experience: In Which the Geometrical Orderliness of Rhythmic Organization Breaks Down in Diverse Ways * 11 The Firefly Machine 12 Energy Metabolism in Cells * 13 The Malonic Acid Reagent ('Sodium Geometrate') * 14 Electrical Rhythmicity and Excitability in Cell Membranes * 15 The Aggregation of Slime Mold Amoebae * 16 Numerical Organizing Centers * 17 Electrical Singular Filaments in the Heart Wall * 18 Pattern Formation in the Fungi * 19 Circadian Rhythms in General * 20 The Circadian Clocks of Insect Eclosion * 21 The Flower of Kalanchoe * 22 The Cell Mitotic Cycle * 23 The Female Cycle * References * Index of Names * Index of Subjects

3,424 citations

Journal ArticleDOI
28 Feb 2007-JAMA
TL;DR: Treatment with beta carotene, vitamin A, vitamin E, and vitamin E may increase mortality and the potential roles of vitamin C and selenium on mortality need further study.
Abstract: ContextAntioxidant supplements are used for prevention of several diseases.ObjectiveTo assess the effect of antioxidant supplements on mortality in randomized primary and secondary prevention trials.Data Sources and Trial SelectionWe searched electronic databases and bibliographies published by October 2005. All randomized trials involving adults comparing beta carotene, vitamin A, vitamin C (ascorbic acid), vitamin E, and selenium either singly or combined vs placebo or vs no intervention were included in our analysis. Randomization, blinding, and follow-up were considered markers of bias in the included trials. The effect of antioxidant supplements on all-cause mortality was analyzed with random-effects meta-analyses and reported as relative risk (RR) with 95% confidence intervals (CIs). Meta-regression was used to assess the effect of covariates across the trials.Data ExtractionWe included 68 randomized trials with 232 606 participants (385 publications).Data SynthesisWhen all low- and high-bias risk trials of antioxidant supplements were pooled together there was no significant effect on mortality (RR, 1.02; 95% CI, 0.98-1.06). Multivariate meta-regression analyses showed that low-bias risk trials (RR, 1.16; 95% CI, 1.05-1.29) and selenium (RR, 0.998; 95% CI, 0.997-0.9995) were significantly associated with mortality. In 47 low-bias trials with 180 938 participants, the antioxidant supplements significantly increased mortality (RR, 1.05; 95% CI, 1.02-1.08). In low-bias risk trials, after exclusion of selenium trials, beta carotene (RR, 1.07; 95% CI, 1.02-1.11), vitamin A (RR, 1.16; 95% CI, 1.10-1.24), and vitamin E (RR, 1.04; 95% CI, 1.01-1.07), singly or combined, significantly increased mortality. Vitamin C and selenium had no significant effect on mortality.ConclusionsTreatment with beta carotene, vitamin A, and vitamin E may increase mortality. The potential roles of vitamin C and selenium on mortality need further study.

2,195 citations

Journal ArticleDOI
Tamar Frankel1
TL;DR: The Essay concludes that practitioners theorize, and theorists practice, use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ.
Abstract: Much has been written about theory and practice in the law, and the tension between practitioners and theorists. Judges do not cite theoretical articles often; they rarely "apply" theories to particular cases. These arguments are not revisited. Instead the Essay explores the working and interaction of theory and practice, practitioners and theorists. The Essay starts with a story about solving a legal issue using our intellectual tools - theory, practice, and their progenies: experience and "gut." Next the Essay elaborates on the nature of theory, practice, experience and "gut." The third part of the Essay discusses theories that are helpful to practitioners and those that are less helpful. The Essay concludes that practitioners theorize, and theorists practice. They use these intellectual tools differently because the goals and orientations of theorists and practitioners, and the constraints under which they act, differ. Theory, practice, experience and "gut" help us think, remember, decide and create. They complement each other like the two sides of the same coin: distinct but inseparable.

2,077 citations