Citations

Abstract Recent population-based studies demonstrate an increased fracture risk with monoclonal gammopathy of undetermined significance (MGUS). The etiology of this increased risk remains unclear, however, because areal bone mineral density (aBMD) measurements by dual-energy x-ray absorptiometry cannot assess bone microstructural properties critical to determining bone quality and strength. To better define the skeletal effects of MGUS, we performed aBMD and high-resolution peripheral quantitative computed tomography volumetric bone mineral density (vBMD) measurements in 50 MGUS patients (20 females, 30 males; mean ± SEM age, 70.5 ± 1.4 years) and 100 matched control subjects. Relative to controls, MGUS patients had decreased aBMD at the femoral neck (P = .05) and total femur (P < .05) but no differences at other sites. In contrast, high-resolution peripheral quantitative computed tomography showed markedly diminished cortical thickness (P < .05) and increased endocortical area (P < .01). Average vBMD (P < .01), cortical vBMD (P < .001), and trabecular thickness (P < .01) were all significantly decreased in MGUS patients, suggestive of impaired bone formation. Serum levels of the Wnt pathway inhibitor Dickkopf-related protein 1 (P < .001) and osteoclast-activating factor MIP-1α (P < .05) also were significantly elevated in MGUS patients. Our data provide the first evidence of altered bone microstructure in MGUS and suggest that cytokines elevated in osteolytic myeloma also may be associated with bone loss in MGUS.

AbstractTo determine cytologic features of epithelioid hemangioendothelioma (EHE) that would enable accurate diagnosis, we evaluated fine-needle aspiration biopsy (FNAB) smears from 11 histologically confirmed EHEs. The variably cellular smears comprised dispersed single cells and occasional cell aggregates. Dense stromal fragments were present in association with some tissue fragments. The cells were epithelioid, containing moderate or large amounts of dense cytoplasm. Nuclei exhibited mild pleomorphism, and nuclear grooves were identified in all cases. At least occasional intranuclear pseudoinclusions (INPIs) and intracytoplasmic lumina (ICLs) were present in all cases and in 9 cases (82%), respectively, and rare erythrocytes were seen within ICLs in 5 cases (45%). Mitotic figures were identified in 4 cases (36%). The background was bloody in 6 cases (55%) and contained hemosiderin and/or hemosiderin-laden macrophages in 5 cases (45%). The combination of the following features in FNAB samples should raise strong suspicion for EHE: predominantly dispersed single cells with occasional cohesive cell clusters; epithelioid cytomorphology; dense cytoplasm with well-defined cytoplasmic borders; ICLs (with or without erythrocytes), INPIs, and nuclear grooves. The presence of these features should prompt correlation with clinical, radiologic, and histologic features and immunohistochemical evaluation using vascular markers.

OBJECTIVES: To evaluate the long-term impact of pediatric central line care practices in reducing PICU central line–associated bloodstream infection (CLA-BSI) rates and to evaluate the added impact of chlorhexidine scrub and chlorhexidine-impregnated sponges. METHODS: A 3-year, multi-institutional, interrupted time-series design (October 2006 to September 2009), with historical control data, was used. A nested, 18-month, nonrandomized, factorial design was used to evaluate 2 additional interventions. Twenty-nine PICUs were included. Two central line care bundles (insertion and maintenance bundles) and 2 additional interventions (chlorhexidine scrub and chlorhexidine-impregnated sponges) were used. CLA-BSI rates (January 2004 to September 2009), insertion and maintenance bundle compliance rates (October 2006 to September 2009), and chlorhexidine scrub and chlorhexidine-impregnated sponge compliance rates (January 2008 to June 2009) were assessed. RESULTS: The average aggregate baseline PICU CLA-BSI rate decreased 56% over 36 months from 5.2 CLA-BSIs per 1000 line-days (95% confidence interval [CI]: 4.4–6.2 CLA-BSIs per 1000 line-days) to 2.3 CLA-BSIs per 1000 line-days (95% CI: 1.9–2.9 CLA-BSIs per 1000 line-days) (rate ratio: 0.44 [95% CI: 0.37–0.53]; P &lt; .0001). No statistically significant differences in CLA-BSI rate decreases between PICUs using or not using either of the 2 additional interventions were found. CONCLUSIONS: Focused attention on consistent adherence to the use of pediatrics-specific central line insertion and maintenance bundles produced sustained, continually decreasing PICU CLA-BSI rates. Additional use of either chlorhexidine for central line entry scrub or chlorhexidine-impregnated sponges did not produce any statistically significant additional reduction in PICU CLA-BSI rates.

Diastolic dysfunction is characterized by the stiffening of the left-ventricular myocardium. An imaging technique capable of quantifying viscoelasticity of the left-ventricle would aid clinicians in evaluating diastolic function. Lamb wave dispersion ultrasound vibrometry (LDUV) is an ultrasound-based method for measuring viscoelasticity of plate-like materials by exciting Lamb waves and measuring change of wave velocity as a function of frequency (dispersion). Lamb wave dispersion equation is fit to the dispersion data to estimate mechanical properties. We report in vivo transthoracic studies aimed at quantifying elasticity and viscosity of a beating porcine left-ventricle using LDUV. A single ultrasound probe operating at 5 MHz was used for impulse excitation in the myocardium and to track the wave motion. A Fourier space-time analysis of the motion was used to obtain Lamb wave velocity dispersion. ECG-gated transthoracic in vivo measurements of group velocity, elasticity, and viscosity throughout a single heart cycle were obtained. Group velocity, elasticity, and viscosity in the frequency range from 50 to 500 Hz increased by at least two-fold from diastole to systole, consistent with contraction and relaxation of the myocardium.

Tissue mechanical properties can be obtained by algebraic direct inversion (ADI) of the shear-wave motion differential equation, which is insensitive to reflection and geometry of the pushing beam. Shear waves normally generated by a focused ultrasound pushing beam have limited spatial extent in depth and are transient in time, leading to noisy and unstable ADI results. A comb-shape acoustic radiation force distribution can generate shear waves with longer spatial extent and time duration, facilitating more robust ADI. For 400 μs, a linear array transducer simultaneously transmitted four unfocused pushing beams (12 on elements for each pushing beam, 8 off elements between beams) into a tissue-mimicking phantom (∼1.5 kPa) with a cylindrical inclusion (∼4 kPa). The ultrasound system (Verasonics Inc.) then immediately switched to flash imaging mode (frame rate = 2 kHz, spatial resolution = 0.31 mm) to measure shear-wave displacements in a 38 mm by 30 mm domain that was used for ADI. The reconstructed 2D shear elasticity map provides accurate shear elasticity estimates (background = 1.5 kPa with 7% variance; inclusion = 3.9 kPa with 15% variance) and excellent contrast between the background and inclusion.