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101.
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Acrylamide (ACM) is a high-volume industrial chemical with diverse uses in manufacturing, construction and laboratory research. ACM is a well-established neurotoxic agent causing peripheral neuropathy with impairment in the arms and legs of exposed workers, most thoroughly studied in Swedish tunnel workers exposed to ACM grouting. A quantitative risk assessment was performed to assess ACM risk to workers. Using data from a published paper investigating peripheral neuropathies in Chinese chemical workers, estimates of exposure response for vibration perception threshold and nerve conduction velocities were calculated, based on hemoglobin adducts and air concentrations as exposure metrics. The benchmark dose procedure was applied in order to calculate excess risks of impairment, defined as adverse performance exceeding the 95th percentile in unexposed populations, at various concentrations of airborne ACM exposure. Under the assumptions in this risk assessment, after three years of inhalation exposure at 0.3 mg/m3, the excess attributable impairment manifest in vibration perception and nerve conduction velocity is estimated to occur in 1-2% of workers. For 10 years at 0.3 mg/m3 ACM inhalation (equivalent to 3 years at 1.0 mg/m3) the excess prevalence of impairment would be 2-14% of workers, assuming the effect continues to accrue linearly in time. Using published data, the risks of impairment from peripheral neuropathy attributable to exclusively airborne ACM exposure can be predicted for exposure periods less than 10 years. The risks associated with dermal and airborne ACM exposures can be estimated by characterizing working process environments using ACM Hb-adduct levels and possibly monitored with urinary biomarkers. 相似文献
103.
《Journal of medical engineering & technology》2013,37(6-7):362-369
An improved method for noninvasive measurement of the local velocity of arterial pulse wave propagation by an echo-tracking-based ultrasound system is described. A data acquisition image interface was programmed in the ultrasound machine simultaneously to record M-mode ultrasound signals at two locations of a given distance apart along an artery. The selections of measurement sites, separation, and time resolution were performed on the control interface. The temporal sampling frequency could be as high as 10?kHz. The displacements of the blood vessel wall along the time axis were calculated from the M-mode signals by cross-correlation of the radio-frequency data and the distension waveforms were obtained. The temporal separation of the feet of the distension curves from the two measurement locations was derived to give the travel time of the pulse wave. Measurements were made in vivo on human carotid arteries. The pulse wave velocities measured from four volunteers were from 4.1 to 7.2 m/s with coefficients of variation from 5.9 to 29.5%. Some of the factors contributing to the variation in measured values of the velocity are discussed. The method is simple to implement and should be suitable for clinical research into local pulse wave velocity. 相似文献
104.
Lawrence G. Rudski Luna Gargani William F. Armstrong Patrizio Lancellotti Steven J. Lester Ekkehard Grünig Michele DAlto Meriam ?str?m Aneq Francesco Ferrara Rajeev Saggar Rajan Saggar Robert Naeije Eugenio Picano Nelson B. Schiller Eduardo Bossone 《Journal of the American Society of Echocardiography》2018,31(5):527-550.e11
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Andreas Hjelm Brandt Kristoffer Lindskov Hansen Caroline Ewertsen Simon Holbek Jacob Bjerring Olesen Ramin Moshavegh Carsten Thomsen Jørgen Arendt Jensen Michael Bachmann Nielsen 《Ultrasound in medicine & biology》2018,44(8):1751-1761
Magnetic resonance phase contrast angiography (MRA) is the gold standard for blood flow evaluation. Spectral Doppler ultrasound (SDU) is the first clinical choice, although the method is angle dependent. Vector flow imaging (VFI) is an angle-independent ultrasound method. The aim of the study was to compare VFI- and SDU-estimated peak systolic velocities (PSV) of the common carotid artery (CCA) with PSV obtained by MRA. Furthermore, intra- and inter-observer agreement was determined. MRA estimates were significantly different from SDU estimates (left CCA: p?<?0.001, right CCA: p?<?0.001), but not from VFI estimates (left CCA: p?=?0.28, right CCA: p?=?0.18). VFI measured lower PSV in both CCAs compared with SDU (p?<?0.001) with improved precision (VFI: left: 24%, right: 18%; SDU: left 38%, right: 23%). Intra- and inter-observer agreement was almost perfect for VFI and SDU (inter-observer correlation coefficient: VFI 0.88, SDU 0.91; intra-observer correlation coefficient: VFI 0.96, SDU 0.97). VFI is more accurate than SDU in evaluating PSV compared with MRA. 相似文献
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108.
Peng Wu ;Aditya Chawla ;Robert J. Spinner ;Cong Yu ;Michael J. Yaszemski ;Anthony J. Windebank ;Huan Wang 《中国神经再生研究》2014,9(20):1796-1809
The neuromuscular junction becomes progressively less receptive to regenerating axons if nerve repair is delayed for a long period of time. It is difficult to ascertain the denervated muscle's residual receptivity by time alone. Other sensitive markers that closely correlate with the extent of denervation should be found. After a denervated muscle develops a fibrillation potential, muscle fiber conduction velocity, muscle fiber diameter, muscle wet weight, and maximal isometric force all decrease; remodeling increases neuromuscular junction fragmentation and plantar area, and expression of myogenesis-related genes is initially up-regulated and then down-regulated. All these changes correlate with both the time course and degree of denervation. The nature and time course of these denervation changes in muscle are reviewed from the literature to explore their roles in assessing both the degree of detrimental changes and the potential success of a nerve repair. Fibrillation potential amplitude, muscle fiber conduction velocity, muscle fiber diameter, mRNA expression levels of myogenic regulatory factors and nicotinic acetylcholine receptor could all reflect the severity and length of denervation and the receptiveness of denervated muscle to regenerating axons, which could possibly offer an important clue for surgical choices and predict the outcomes of delayed nerve repair. 相似文献
109.
110.
Pasquale Palmiero M.D. Maria Maiello M.D. David D. Daly Jr. M.D. Marco Matteo Ciccone M.D. Navin C. Nanda M.D. 《Echocardiography (Mount Kisco, N.Y.)》2012,29(10):1233-1238
Objective: The first goal of our study was to investigate major determinants of aortic stiffness in postmenopausal women using an echocardiographic method to calculate global pulse wave velocity (PWVg) rather than the less accurate carotid–femoral pulse wave velocity (PWVc). The second goal was to relate PWVg to the absolute risk of major cardiovascular (CV) events estimated by CV risk factors. Patients and methods: Two hundred forty‐four consecutive women who presented to our heart station were screened. One hundred twenty‐two were postmenopausal, either natural or surgical, whereas 122 were premenopausal. The mean age of the patients was 54 ± 13 years. Individuals were categorized as current smokers, former smokers, or nonsmokers and hypertensive or not. Hypercholesterolemia and diabetes mellitus were defined. Aortic stiffness was assessed by PWVg measured with pulsed Doppler, the interval between the beginning of QRS complex and the foot of the systolic upstroke in the Doppler spectral envelope was calculated at the aortic valve site and at the right common femoral artery. PWVg was calculated between the aortic valve and right common femoral artery by dividing the straight line distance between the two by the transit time. Results: There was a highly significant statistical difference (P < 0.0012) in PWVg between menstruating women and postmenopausal women. Similarly, this difference in PWVg was also noted among the menstruating population (P < 0.0014) when comparing normotensive women and hypertensive women. In postmenopausal women, PWVg was 6.8 m/sec in normotensive women and 7.56 m/sec in hypertensive women (P < 0.007). Conclusion: PWVg was increased in postmenopausal women compared with menstruating women. Systemic hypertension has an independent, but additive effect on aortic stiffness assessed by PWVg. Our study supports the usefulness of the assessment of aortic stiffness as a marker of CV disease and to identify subjects at risk at an early age. 相似文献