Characterizing applications, exposure risks, and hazard communication for engineered nanomaterials in construction.

BACKGROUND: Engineered nanomaterials (ENMs) may pose health risks to workers. Objectives were to characterize ENM applications in construction, identify exposure scenarios, and evaluate the quality of safety data sheets (SDSs) for nano-enabled construction products. METHODS: SDSs and product data were obtained from a public database of nano-enabled construction products. Descriptive statistics were calculated for affected trades, product categories, and types of ENMs. A sample of SDSs (n = 33) was evaluated using modified criteria developed by NIOSH researchers. Bulk analysis via transmission electron microscopy characterized nanoparticles in a subset of products. RESULTS: Companies report using >50 ENMs in construction products. ENM composition could not be determined via SDSs for 38.1% of the 907 products examined. Polymers and metal oxides tied for most frequently reported ENMs (n = 87, 9.6%). Nano silica, graphene, carbon nanotubes, and silver nanoparticles were also frequently reported. Most of the products were paints and coatings (n = 483, 53.3%), followed by pre-market additives, cementitious materials, insulation, and lubricants. Workers in twenty construction trades are likely to handle nano-enabled products, these particularly encompass cement and brick masons, painters, laborers, carpenters, glaziers, and insulators. A wide range of exposure scenarios were identified. SDSs were classified as satisfactory (18%), in need of improvement (12%), or in need of significant improvement (70%). Bulk analyses revealed discrepancies between actual ENM composition and those in SDSs. DISCUSSION AND CONCLUSION: There has been significant progress investigating risks to construction workers posed by ENMs, but SDSs need major improvements. This study provides new insights on the use of ENMs in construction, exposure risks, and hazard communication.

Occupational exposure risk during spraying of biocidal paint containing silver nanoparticles.

The study assessed potential to exceed occupational exposure limits while spraying paint with and without a silver nanoparticle biocidal additive. A tradesperson performed the tasks in a sealed chamber with filtered air supply. Integrated air sampling entailed transmission electron microscopy with energy dispersive X-ray analysis, direct-reading of particle number concentrations, and determination of silver mass concentration by NIOSH Method 7300. Silver nanoparticles were primarily embedded in paint spray droplets but also observed as isolated particles. Using an α-level of 0.05, median nanoparticle number concentrations did not differ significantly when spraying conventional vs. biocidal paint, although statistically significant differences were observed at specific particle size ranges <100 nm. The geometric mean concentration of total silver while spraying biocidal paint (n = 6) was 2.1 µg/m3 (95% CI: 1.5-2.8 µg/m3), and no respirable silver was detected (<0.50 µg/m3). The results address a lack of silver nanoparticle exposure data in construction and demonstrate the feasibility of a practical sampling approach. Given similar conditions, the measurements suggest a low probability of exceeding a proposed silver nanoparticle exposure limit of 0.9 µg/m3 as an airborne 8-hr time-weighted average respirable mass concentration. A full workday of exposure to respirable silver at the highest possible level in this study (<0.50 µg/m3) would not exceed the exposure limit, although limitations in comparing short task-based exposures to an 8-hr exposure limit must be noted. There was airflow in the study chamber, whereas exposure levels could increase over time in work environments lacking adequate ventilation. Potential to exceed the exposure limit hinged upon the respirable fraction of the paint mist, which could vary by material and application method. Additional research would improve understanding of silver nanoparticle exposure risks among construction trades, and biological responses to these exposures. Given the potential for exposure variability on construction jobsites, safety and health professionals should be cognizant of methods to assess and control silver nanoparticle exposures.

Flow Patterns in the Carotid Arteries of Patients with Left Ventricular Assist Devices.

BACKGROUND: The aim of this study is to evaluate and define the expected flow pattern changes of carotid artery duplex ultrasound after left ventricular assist device (LVAD) placement. METHODS: Retrospective review of Henry Ford Hospital database of patients who had undergone LVAD placement between March 2008 and July 2012 was performed. All patients who had carotid artery duplex scanning before and after LVAD placement within 2 years of each other and showed <50% stenosis were included in this study. Type of waveform, carotid peak systolic velocity, and end-diastolic velocities were analyzed, and the values were compared before and after LVAD placement. RESULTS: A total of 13 patients with LVAD had at least 2 carotid duplex studies before and after LVAD placement within 2 years of each other. Of those, 92% (n = 12) were men, and 61% (n = 8) were Caucasian. Mean age was 61 years old. The HeartWare ventricular assist device was implanted in 4 patients and the HeartMate II left ventricular assist device was implanted in 9 patients. Post-LVAD Doppler imaging demonstrated parvus tardus waveform. Analysis of flow velocities revealed that peak systolic velocity was diminished after LVAD placement in both the internal and common carotid arteries (P = 0.006 and P < 0.0001, respectively). End-diastolic velocity, however, increased post-LVAD (P < 0.0001). Interestingly, mean flow velocities in both the common and internal carotid arteries remained stable after LVAD placement. CONCLUSIONS: This study reveals changes in waveform morphology and peak systolic and diastolic velocities in the common and internal carotid arteries on carotid duplex after LVAD placement. Additionally, it shows that despite changes in post-LVAD pulse pressure in the carotid arteries, the mean flow velocity remained unchanged.

Clinical utility of carotid duplex ultrasound prior to cardiac surgery.

OBJECTIVE: Clinical utility and cost-effectiveness of carotid duplex examination prior to cardiac surgery have been questioned by the multidisciplinary committee creating the 2012 Appropriate Use Criteria for Peripheral Vascular Laboratory Testing. We report the clinical outcomes and postoperative neurologic symptoms in patients who underwent carotid duplex ultrasound prior to open heart surgery at a tertiary institution. METHODS: Using the combined databases from our clinical vascular laboratory and the Society of Thoracic Surgery, a retrospective analysis of all patients who underwent carotid duplex ultrasound within 13 months prior to open heart surgery from March 2005 to March 2013 was performed. The outcomes between those who underwent carotid duplex scanning (group A) and those who did not (group B) were compared. RESULTS: Among 3233 patients in the cohort who underwent cardiac surgery, 515 (15.9%) patients underwent a carotid duplex ultrasound preoperatively, and 2718 patients did not (84.1%). Among the patients who underwent carotid screening vs no screening, there was no statistically significant difference in the risk factors of cerebrovascular disease (10.9% vs 12.7%; P = .26), prior stroke (8.2% vs 7.2%; P = .41), and prior transient ischemic attack (2.9% vs 3.3%; P = .24). For those undergoing isolated coronary artery bypass grafting (CABG), 306 (17.8%) of 1723 patients underwent preoperative carotid duplex ultrasound. Among patients who had carotid screening prior to CABG, the incidence of carotid disease was low: 249 (81.4%) had minimal or mild stenosis (<50%); 25 (8.2%) had unilateral moderate stenosis (50%-69%); 10 (3.3%) had bilateral moderate stenosis; 9 (2.9%) had unilateral severe stenosis (70%-99%); 5 (1.6%) had contralateral moderate stenosis; 2 (0.7%) had bilateral severe stenosis; 4 (1.3%) had unilateral occluded with contralateral less than 50% stenosis, 1 (0.3%) had unilateral occluded with contralateral (70%-99%) stenosis; and 1 had bilateral occluded carotid arteries. Primary outcomes of patients who underwent isolated CABG showed no difference in the perioperative mortality (2.9% vs 4.3%; P = .27) and stroke (2.9% vs 2.6%; P = .70) between patients undergoing preoperative duplex scanning and those who did not. Primary outcomes of patients who underwent open heart surgery also showed no difference in the perioperative mortality (5.1% vs 6.9%; P = .14) and stroke (2.6% vs 2.4%; P = .85) between patients undergoing preoperative duplex scanning and those who did not. Operative intervention of severe carotid stenosis prior to isolated CABG occurred in 2 of the 17 patients (11.8%) identified who underwent carotid endarterectomy with CABG. CONCLUSIONS: In this study, the correlation between preoperative duplex-documented high-grade carotid stenosis and postoperative stroke was low. Prudent use of preoperative carotid duplex ultrasound should be based on the presence of cerebrovascular symptoms and the type of open heart surgery.

Nephrogenic systemic fibrosis with a spectrum of clinical and histopathological presentation: a disorder of aberrant dermal remodeling.

BACKGROUND: Nephrogenic fibrosing dermopathy (NFD) has emerged as a clinicopathologic entity since 1997 and recently renamed as nephrogenic systemic fibrosis (NSF). The etiology and pathogenesis remain uncertain. Characteristic clinical presentation is described as diffuse thickening and hardening of the skin occurring in patients with renal insufficiency. Typical histological features include proliferation of CD34 positive fibrocytes, increased thick collagen bundles and mucin deposition, without significant inflammatory infiltrate. Variations in clinical presentations have been reported, including papular and plaque-like skin lesions, focal lesion only, as well as systemic involvement. Histological changes can be subtle and non-specific, overlapping with other disease processes and harboring features including calcification and osteoclast-like giant cells with osseous metaplasia. METHODS: We reviewed patients with NSF that presented to our dermatology clinic by chart review, clinical examination and histological examination. Skin biopsy specimens were obtained from all cases. Histopathology evaluations were carried out by three dermatopathologists (AD, BS and GK) independently and the features were compared among all the cases. Special stains and immunohistochemistry study were also performed to highlight the histological features. RESULTS: Seven cases of NSF presented with a spectrum of clinical manifestations, from classic diffuse hardening of the skin to localized linear plaques. On histological examination, proliferation of CD34-positive fibrocytes ranged from sparse to dense, collagen bundles ranged from thin to thick, and the interstitial dermal mucin accumulation ranged from scant-patchy to abundant. In addition, the lesion displayed various degrees of vascular proliferation, inflammatory infiltrates and intensities of CD68 and Factor XIIIa staining. Two cases showed extensive dermal calcification and ossification. CONCLUSION: NSF may present with a spectrum of clinical abnormalities, and exhibit overlapping histopathological features resembling cicatrix and other dermal reparative/regenerative processes. NSF may in fact to be a disorder of aberrant extracellular matrix remodeling in patients with renal insufficiency.

Kangaroo care and breastfeeding of mother-preterm infant dyads 0-18 months: a randomized, controlled trial.

PURPOSE: To determine the effects of kangaroo care (KC) (skin-to-skin contact) on breastfeeding status in mother-preterm infant dyads from postpartum through 18 months. DESIGN: Randomized, controlled trial. The control group received standard nursery care; in the intervention group, unlimited KC was encouraged. SAMPLE: A subsample of 66 mothers and their preterm infants (32-36 completed weeks gestation, 1,300-3,000 g, 5 minute Apgar > or = 6) who intended to breastfeed. MAIN OUTCOME VARIABLES: Breastfeeding status at hospital discharge and at 1.5, 3, 6, 12, and 18 months as measured by the Index of Breastfeeding Status. RESULTS: KC dyads, compared to control dyads, breastfed significantly longer (5.08 months vs 2.05 months), p = .003. KC dyads also breastfed more exclusively at each measurement, p = .047. More KC dyads than control dyads breastfed at full exclusivity (100 percent breast milk, index of breastfeeding status levels 1 or 2) at discharge and at 1.5, 3, and 6 months. Mean KC contact per day was 4.47 hours.