A rapid and sensitive method to detect single-walled carbon nanotubes (SWNTs) in biological samples is presented. The method uses polyacrylamide gel electrophoresis (PAGE) followed by quantification of SWNT bands. SWNTs dispersed in bovine serum albumin (BSA) were used to develop the method. When BSA-SWNT dispersions were subjected to sodium dodecyl sulfate (SDS)-PAGE, BSA passed through the stacking gel, entered the resolving gel, and migrated toward the anode as expected. The SWNTs, however, accumulated in a sharp band at the interface between the loading well and the stacking gel. The intensities from digitized images of these bands were proportional to the amount of SWNTs loaded onto the gel with a detection limit of 5 ng of SWNTs. To test the method, normal rat kidney (NRK) cells in culture were allowed to take up SWNTs upon exposure to medium containing various concentrations of BSA-SWNTs for different times and temperatures. The SDS-PAGE analyses of cell lysate samples suggest that BSA-SWNTs enter NRK cells by fluid-phase endocytosis at a rate of 30 fg/day/cell upon exposure to medium containing 98 microg/mL SWNTs.

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND AND OBJECTIVES: Recently, the Neonatal Resuscitation Program (NRP) recommended against routine endotracheal suctioning of meconium-stained nonvigorous newborns but suggested resuscitation with positive pressure ventilation. Our purpose is to study the effects of this change in management. METHODS: In this multicenter cohort study, we compare 130 nonvigorous newborns born during the retrospective 1-year period before the implementation of new NRP guidelines (October 1, 2015, to September 30, 2016) to 101 infants born during the 1-year prospective period after implementation (October 1, 2016, to September 30, 2017). RESULTS: Endotracheal suctioning was performed predominantly in the retrospective group compared with the prospective group (70% vs 2%), indicating the change in practice. A significantly higher proportion of newborns were admitted to the NICU for respiratory issues in the prospective group compared with the retrospective group (40% vs 22%) with an odds ratio (OR) of 2.2 (95% confidence interval [CI]: 1.2-3.9). Similarly, a significantly higher proportion of infants needed oxygen therapy (37% vs 19%) with an OR of 2.5 (95% CI: 1.2-4.5), mechanical ventilation (19% vs 9%) with an OR of 2.6 (95% CI: 1.1-5.8), and surfactant therapy (10% vs 2%) with an OR of 5.8 (95% CI: 1.5-21.8). There were no differences in the incidence of other outcomes, including meconium aspiration syndrome. CONCLUSIONS: The recent NRP guideline change was not associated with an increased incidence of meconium aspiration syndrome but was associated with an increased incidence of NICU admissions for respiratory issues. Also, the need for mechanical ventilation, oxygen, and surfactant therapy increased.

Legg-Calvé-Perthes disease (LCPD) is a childhood hip disorder of ischemic osteonecrosis of the femoral head. Hip joint synovitis is a common feature of LCPD, but the nature and pathophysiology of the synovitis remain unknown. The purpose of this study was to determine the chronicity of the synovitis and the inflammatory cytokines present in the synovial fluid at an active stage of LCPD. Serial MRI was performed on 28 patients. T2-weighted and gadolinium-enhanced MR images were used to assess synovial effusion and synovial enhancement (hyperemia) over time. A multiple-cytokine assay was used to determine the levels of 27 inflammatory cytokines and related factors present in the synovial fluid from 13 patients. MRI analysis showed fold increases of 5.0 AE 3.3 and 3.1 AE 2.1 in the synovial fluid volume in the affected hip compared to the unaffected hip at the initial and the last follow-up MRI, respectively. The mean duration between the initial and the last MRI was 17.7 AE 8.3 months. The volume of enhanced synovium on the contrast MRI was increased 16.5 AE 8.5 fold and 6.3 AE 5.6 fold in the affected hip compared to the unaffected hip at the initial MRI and the last follow-up MRI, respectively. In the synovial fluid of the affected hips, IL-6 protein levels were significantly increased (LCPD: 509 AE 519 pg/mL, non-LCPD: 19 AE 22 pg/mL; p ¼ 0.0005) on the multi-cytokine assay. Interestingly, IL-1b and TNF-a levels were not elevated. In the active stage of LCPD, chronic hip synovitis and significant elevation of IL-6 are produced in the synovial fluid. Further studies are warranted to investigate the role of IL-6 on the pathophysiology of synovitis in LCPD and how it affects bone healing.