Mathematical Modeling of Serum 13C-Retinol in Captive Rhesus Monkeys Provides New Insights on Hypervitaminosis A1–3

Hypervitaminosis A is increasingly a public health concern, and thus noninvasive quantitative methods merit exploration. In this study, we applied the 13C-retinol isotope dilution test to a nonhuman primate model with excessive liver stores. After baseline serum chemistries, rhesus macaques (Macaca mulatta; n = 16) were administered 3.5 μmol 13C2-retinyl acetate. Blood was drawn at baseline, 5 h, and 2, 4, 7, 14, 21, and 28 d following the dose. Liver biopsies were collected 7 d before and 2 d after dosing (n = 4) and at 7, 14, and 28 d (n = 4/time) after dosing. Serum and liver were analyzed by HPLC and GC-combustion-isotope ratio MS for retinol and its enrichment, respectively. Model-based compartmental analysis was applied to serum data. Lactate dehydrogenase was elevated in 50% of the monkeys. Total body reserves (TBR) of vitamin A (VA) were calculated at 28 d. Predicted TBR (3.52 ± 2.01 mmol VA) represented measured liver stores (4.56 ± 1.38 mmol VA; P = 0.124). Predicted liver VA concentrations (13.3 ± 9.7 μmol/g) were similar to measured liver VA concentrations (16.4 ± 5.3 μmol/g). The kinetic models predict that 27–52% of extravascular VA is exchanging with serum in hypervitaminotic A monkeys. The test correctly diagnosed hypervitaminosis A in all monkeys, i.e. 100% sensitivity. Stable isotope techniques have important public health potential for the classification of VA status, including hypervitaminosis, because no other technique besides invasive liver biopsies, correctly identifies excessive liver VA stores

Nurses' Attitudes Toward Patients with Sickle Cell Disease: A Worksite Comparison

BACKGROUND: Individuals with sickle cell disease (SCD) have reported being stigmatized when they seek care for pain. Nurse attitudes contribute to stigmatization and may affect patients' response to sickle cell cues, care-seeking, and ultimately patient outcomes. AIM: The purpose of this study was to determine if there are significant differences in nurse attitudes towards patients with SCD by worksite- medical-surgical units compared to emergency departments/intensive care units (ED/ICU). DESIGN: The study used a cross-sectional, descriptive comparative design. SETTING/PARTICIPANTS: The sample consisted of 77 nurses (36 nurses from the ED/ICU and 41 nurses from medical-surgical units) who completed an anonymous online survey. RESULTS AND CONCLUSIONS: There were no significant differences in attitudes by worksite with both sites having high levels of negative attitudes towards patients with SCD. Findings suggest that nurses from both worksites need additional education about SCD and care of this vulnerable, patient population