Purpose:To establish the specificity of T 1 with respect to fixed charge density (FCD) as a measure of proteoglycan (PG) content in cartilage during the onset of osteoarthritis (OA). Materials and Methods:T 1 -weighted and sodium MRI were performed on cartilage samples of enzymatically degraded bovine explants and natural osteoarthritic human samples representing controlled and physiological models of OA, respectively. Spatial maps of T 1 and FCD (measured using the previously validated method of sodium MRI) were calculated from image data. Data were extracted from the maps and subjected to linear regression to compare changes in T 1 with changes in FCD in each model. Tissue samples were subjected to histological staining for a reduction in PG content.Results: Plots of normalized T 1 rate vs. FCD were found to be strongly correlated (R 2 Ͼ 0.75 and 0.85) in both models with nearly the same slope of Ϸ1/2 (P Ͼ 0.51). Loss of PG in bovine and human tissue was confirmed by histology. Conclusion:The strong correlation of the FCD and T 1 data in both the controlled and physiological models demonstrates that changes in T 1 are due predominantly to changes in PG content. This work is a first step in establishing T 1 as a method of quantifying PG changes in early-stage OA. THE PATHOLOGY OF THE disease osteoarthritis (OA) results in significant changes to the biochemical composition of cartilage. Loss of proteoglycan content (PG) from the extracellular matrix (ECM) is characteristic of the early development of OA (1-3). Although changes in collagen content and structure have been discerned, during the beginning stages of the disease the collagenous component of the ECM is often preserved (3-5). A noninvasive technique to detect biochemical changes that precede morphological degeneration in tissue will have a substantial impact on early diagnosis and the evaluation of therapeutic efficacy of treatment.The sodium MRI method has previously been established as an accurate measure of fixed charge density (FCD), as validated by spectrophotometric assay (6). The direct relationship between FCD and PG allows FCD data obtained via sodium MRI to be used as a spatially resolved measure of PG. Since the FCD measurement is affected only by charged species, sodium MRI provides a highly specific measure of PG and can be used as a gold standard for validating other methods of PG quantification.A promising alternative to sodium MRI to detect PG changes in vivo is T 1 -weighted MRI (7). T 1 , the spinlattice relaxation in the rotating frame, is sensitive to low frequency interactions between water molecules and their local macromolecular environment, such as the PG constituent of the ECM in cartilage. T 1 -weighting can be incorporated into an MR imaging sequence by "T 1 -preparing" the magnetization using a long duration spin-lock pulse. The amplitude of the spin-lock pulse is commonly referenced in terms of its nutation frequency (␥B 1 ), which is on the order of a few kilohertz. T 1 is sensitive to molecular interaction processes having...

Background Ischemia depletes antioxidant reserves and impairs mitochondrial electron transport. Oxygen within blood reperfusing ischemic tissue can form free radicals, worsen oxidative stress and exacerbate tissue injury (reperfusion injury). One strategy for limiting reperfusion injury is to limit delivery of “luxuriant” oxygen during or after reperfusion. Resuscitation guidelines for children with cardiac arrest recommend early weaning of supplemental oxygen as tolerated. There are currently no studies demonstrating the frequency and outcomes of hyperoxia and hypoxia after pediatric CA. Objective To determine the frequency and outcomes of hyperoxia and hypoxia in patients following resuscitation from pediatric cardiac arrest admitted to a tertiary care center. Design and Methods This is a retrospective observational cohort study. Charts of children resuscitated from cardiac arrest and admitted to our hospital from 2004-2008 were reviewed. Partial pressures of oxygen (PaO2) obtained within the first 24 hours following return of spontaneous circulation and mortality at 6 months was recorded. Children who did not survive the initial 48 hours, patients having undergone extracorporeal oxygenation (ECMO) or had congenital heart disease, and those in whom arterial blood gases (ABG) were not obtained were excluded. Results Seventy-four patients met inclusion criteria. Of these, 38 (51%) had at least one ABG with a Pa02 > 300 mm Hg and 10 (14%) had a Pa02 < 60 mmHg in the first 24 hours. Neither hyperoxia nor hypoxia on initial ABG (p=0.912 and p=0.384) nor any ABG within the first 24 hours after CA (p=0.325 and p=0.553) was associated with 6 month mortality. Conclusions Hyperoxia occurs commonly within the first 24 h of management in children resuscitated from cardiac arrest.

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OBJECTIVES:This pilot study investigated the feasibility and effect on health care utilization of medically complex children participating in a pharmacist-led model for care coordination. Quality of life and satisfaction with care were secondarily assessed for each patient. METHODS: Four medically complex children were enrolled and contacted by the pharmacist weekly for 5 consecutive months. Time for each encounter with a patient was collected. Each patient's hospital admissions, days of stay, emergency department visits, and clinic visits were recorded. At enrollment and at the end of the study, each caregiver completed the PedsQL 4.0 questionnaire to evaluate the child's quality of life and the Patient Assessment of Care for Chronic Conditions questionnaire to assess satisfaction with care. Patients aged 5 years and older completed an age-appropriate version of the PedsQL 4.0 as well. RESULTS:The pharmacist spent on average 60 to 80 minutes per patient per week. Hospital admissions and days of stay decreased for 3 patients and increased for 1 patient during this study. Quality of life increased for 2 patients and decreased for 2 patients and satisfaction with care increased for all 4 caregivers. CONCLUSIONS: This model was feasible for a pharmacist to coordinate and required frequent physician involvement. Health care utilization varied between patients, but overall decreased for the 4 patients pooled. Changes in quality of life varied and may be attributed to using a survey that was not specific to medically complex children. Overall, caregivers were highly satisfied with this service and the health care their child received.INDEX TERMS: care coordination, child, medical home, patient-centered, pediatric J Pediatr Pharmacol Ther 2016;21(4): [346][347][348][349][350][351][352]