Effectiveness of dust control methods for crystalline silica and respirable suspended particulate matter exposure during manual concrete surface grinding

Concrete grinding exposes workers to unacceptable levels of crystalline silica dust, known to cause diseases such as silicosis and possibly lung cancer. This study examined the influence of major factors of exposure and effectiveness of existing dust control methods by simulating field concrete grinding in an enclosed workplace laboratory. Air was monitored during 201 concrete grinding sessions while using a variety of grinders, accessories, and existing dust control methods, including general ventilation (GV), local exhaust ventilation (LEV), and wet grinding. Task-specific geometric mean (GM) of respirable crystalline silica dust concentrations (mg/m3 for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled-grinding, while GV was off/on, were 0.17/0.09, 0.57/0.13, 1.11/0.44, and 23.1/6.80, respectively. Silica dust concentrations (mg/m3 using 100-125 mm (4-5 inch) and 180 mm (7 inch) grinding cups were 0.53/0.22 and 2.43/0.56, respectively. GM concentrations of silica dust were significantly lower for (1) GV on (66.0%) vs. off, and (2) LEV:HEPA- (99.0%), LEV:Shop-vac- (98.1%) or wet- (94.4%) vs. uncontrolled-grinding. Task-specific GM of respirable suspended particulate matter (RSP) concentrations (mg/m3 for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled grinding, while GV was off/on, were 1.58/0.63, 7.20/1.15, 9.52/4.13, and 152/47.8, respectively. GM concentrations of RSP using 100-125 mm and 180 mm grinding cups were 4.78/1.62 and 22.2/5.06, respectively. GM concentrations of RSP were significantly lower for (1) GV on (70.2%) vs. off, and (2) LEV:HEPA- (98.9%), LEV:Shop-vac- (96.9%) or wet- (92.6%) vs. uncontrolled grinding. Silica dust and RSP were not significantly affected by (1) orientation of grinding surfaces (vertical vs. inclined); (2) water flow rates for wet grinding; (3) length of task-specific sampling time; or, (4) among cup sizes of 100, 115 or 125 mm. No combination of factors or control methods reduced an 8-hr exposure level to below the recommended criterion of 0.025 mg/m3 for crystalline silica, requiring further refinement in engineering controls, administrative controls, or the use of respirators.     

Schwann cell transplantation exerts neuroprotective roles in rat model of spinal cord injury by combating inflammasome activation and improving motor recovery and remyelination

Metabolic Brain Disease - Inflammasome activation in the traumatic central nervous system (CNS) injuries is responsible for propagation of an inflammatory circuit and neuronal cell death resulting...     

Clinical characteristics, hospital morbidity and mortality, and up to 1-year follow-up events of acute myocardial infarction patients: the first report from Iran

BACKGROUND: Few data exist about the clinical epidemiology of acute myocardial infarction and its complications and mortality in Iran. To fill this knowledge gap, we studied clinical characteristics and the outcome for a group of Iranian patients with acute myocardial infarction, who were, for the first time in our country, followed after discharge from hospital for 1 year. METHODS: All patients (139 individuals) with confirmed acute myocardial infarction who were treated at the coronary care unit of Dr Shariati Hospital and followed up over a 1-year period (June 2002 to June 2003) were prospectively studied. Numerous relevant variables including epidemiologic data, treatments received, in-hospital course and complications were recorded. The survivors were followed at 1, 6 and 12 months after discharge. RESULTS: In all, there were 101 men and 38 women aged 58.6+/-11.8 years. Only 35.9% of patients received thrombolytic therapy, and primary percutaneous coronary intervention was performed in 6.4% of cases. In-hospital death occurred in 21 of 139 (15.1%), with an equal distribution between the two sexes. One-month, 6-month and 12-month cumulative mortality rates were 17.3, 20.1 and 21.6%, respectively. CONCLUSION: Although our patients were younger than myocardial infarction patients in developed countries, they had a higher rate of in-hospital mortality than those of the international statistics. This may be due, in part, to the lower rate of administration of primary reperfusion strategies in our center, namely primary percutaneous coronary intervention and thrombolytic therapy, which have proved to be effective in reducing the mortality from myocardial infarction in the west. Wider application of primary percutaneous coronary intervention, in particular, is recommended.     

Two novel mutations found in a patient with 17alpha-hydroxylase enzyme deficiency

CONTEXT: Congenital adrenal hyperplasia resulting from 17alpha-hydroxylase deficiency (17OHD) is a rare disorder associated with hypertension. SUBJECT AND METHODS: We describe a phenotypically and hormonally affected female patient with 17OHD. DNA sequencing of her CYP17 gene revealed a maternal heterozygous mutation in exon 2 (R125Q) and a paternal heterozygous mutation in exon 8 (R416H). These are novel mutations in the CYP17 gene that completely eliminate enzyme activity. CONCLUSION: Identification of novel mutations in the CYP17 gene is vital in understanding the molecular mechanisms of its deficiency and in providing additional information about the structure and enzymatic functions of P450c17.     

Aortic valve cusp aneurysm as a result of blood culture-negative infective endocarditis,interesting echocardiographic and surgical images

Compared to mitral valve aneurysms, aortic valve (AV) aneurysm is a more rare and serious complication of infective endocarditis (IE). Early surgical intervention and valve replacement are required in order to prevent further complications such as embolization and rupture of aneurysm. We described a case of severe aortic regurgitation (AR) as a result of an aortic valve aneurysm in a patient with history of end-stage renal disease (ESRD) in whom the hemodialysis catheter had not been changed for a year.     

Approximation of Resting Energy Expenditure in Intensive Care Unit Patients Using the SenseWear Bracelet: A Comparison With Indirect Calorimetry

Background and Aims: Indirect calorimetry (IC) is the gold standard for determining energy expenditure in patients requiring mechanical ventilation. Metabolic armbands using data derived from dermal measurements have been proposed as an alternative to IC in healthy subjects, but their utility during critical illness is unclear. The aim of this study was to determine the level of agreement between the SenseWear armband and the Deltatrac Metabolic Monitor in mechanically ventilated intensive care unit (ICU) patients. Methods: Adult ICU patients requiring invasive ventilator therapy were eligible for inclusion. Simultaneous measurements were performed with the SenseWear Armband and Deltatrac under stable conditions. Resting energy expenditure (REE) values were registered for both instruments and compared with Bland‐Altman plots. Results: Forty‐two measurements were performed in 30 patients. The SenseWear Armband measured significantly higher REE values as compared with IC (mean bias, 85 kcal/24 h; P = .027). Less variability was noted between individual SenseWear measurements and REE as predicted by the Harris‐Benedict equation (2 SD, ±327 kcal/24 h) than when IC was compared with SenseWear and Harris‐Benedict (2 SD, ±473 and ±543 kcal/24 h, respectively). Conclusions: The systematic bias and large variability of the SenseWear armband when compared with gas exchange measurements confer limited benefits over the Harris Benedict equation in determining caloric requirements of ICU patients.     

Single-walled carbon nanotube,multi-walled carbon nanotube and Fe2O3 nanoparticles induced mitochondria mediated apoptosis in melanoma cells

Purpose: Nanomaterials (NM) exhibit novel anticancer properties.

Materials and methods: The toxicity of three nanoparticles that are currently being produced in high tonnage including single-walled carbon nanotube (SWCNT), multi-walled carbon nanotube (MWCNT) and Fe₂O₃ nanoparticles, were compared with normal and melanoma cells.

Results: All tested nanoparticles induced selective toxicity and caspase 3 activation through mitochondria pathway in melanoma cells and mitochondria cause the generating of reactive oxygen species (ROS), mitochondrial membrane potential decline (MMP collapse), mitochondria swelling, and cytochrome c release. The pretreatment of butylated hydroxytoluene (BHT), a cell-permeable antioxidant and cyclosporine A (Cs. A), a mitochondrial permeability transition (MPT), pore sealing agent decreased cytotoxicity, caspase 3 activation, ROS generation, and mitochondrial damages induced by SWCNT, MWCNT, and IONPs.

Conclusions: Our promising results provide a potential approach for the future therapeutic use of SWCNT, MWCNT, and IONPs in melanoma through mitochondrial targeting.