[Neural network analysis of mechanization's impact on coal miner's occupational health].

In order to clarify the transmission mechanism of the impact of mechanization on the occupational health of miners and to provide empirical evidence for the development of new quality productivity in the coal industry that balances health and efficiency. In August 2022, we selected a typical coal mine, constructed a comprehensive evaluation index of miners' occupational health through a questionnaire survey based on the fully connected neural network model. A Bayesian model was used to verify the influence of mechanization level on miners' occupational health. We found that: the predicted probability of occupational diseases could be used as a comprehensive indicator of the level of occupational health, providing a basis for early intervention and prevention of occupational diseases. Mechanization could directly promote the improvement of miners' occupational health level, and also indirectly affect occupational health level by influencing hazards level and work intensity. The indirect effect of mechanization on work intensity was positive, and the indirect effect of mechanization on hazards level was positive. Presented the "inverted U-shaped" process in the mechanization breakthrough semi-mechanized level would realize the economies of scale of health protection, its impact on the prevention and control of occupational hazards would turn from negative to positive.

[Clinical characteristics of acute pulmonary embolism at different altitudes in plateau areas].

Objective: To analyze the clinical characteristics of pulmonary embolism patients from different altitudes in plateau areas. Methods: A retrospective cross-sectional study was used to analyze the patients with acute pulmonary embolism diagnosed definitely by pulmonary angiography or pulmonary artery CT angiography admitted to Tibet Autonomous Region People's Hospital from August 2014 to December 2018. The subjects were divided into 3 groups according to the altitude of long-term residence before onset, i.e. low-altitude group (group 1, 2 700 m ≤ altitude ≤3 700 m, n=44), medium-altitude group (group 2, 3 700 m

Pleckstrin homology-like domain family B member 1 rs498872 polymorphism and glioma risk in Chinese Han population.

This case-control study aimed to investigate the association between PHLDB1 rs498872 polymorphism and the risk of glioma in a Chinese Han population. A total of 210 patients and 235 controls were enrolled in this study. The CT genotype and TT genotype were significantly associated with the risk of glioma (OR=1.48, 95%CI 1.00-2.19, P=0.05 and OR=2.40, 95%CI 1.06-4.10, P=0.03), respectively. In addition, T allele of PHLDB1 rs498872 polymorphism was significantly associated with an increased risk of glioma (OR=1.58, 95%CI 1.08-2.29, P=0.02). We also found that PHLDB1 rs498872 polymorphism was not associated with histology and tumor grade of glioma. In conclusion, this study found that PHLDB1 rs498872 polymorphism was significantly associated with glioma risk in Chinese Han population.

[Intervention of systolic pressure and left ventricular hypertrophy in rats under cold stress].

OBJECTIVE: To investigate the effects of different drugs on systolic blood pressure (SBP) and left ventricular hypertrophy (LVH) in spontaneously hypertensive rats under cold stress. METHODS: A total of 40 male spontaneously hypertensive rats aged 10 weeks (160~200 g) were given adaptive feeding for 7 days at a temperature of 20±1°C and then randomly divided into control group, cold stress group, metoprolol group, amlodipine group, and benazepril group, with 8 rats in each group. SBP, body weight, and heart rate were measured once a week. After the rats were sacrificed by exsanguination, left ventricular weight (LVW) was measured, and left ventricular weight index (LVWI; mg/g) was calculated. Radioimmunoassay was used to measure the concentrations of endothelin-1 (ET-1) and angiotensin-II (Ang-II) in plasma and myocardium, and the chemical method was used to measure the concentrations of nitric oxide (NO) in plasma and myocardium. RT-PCR was used to measure the mRNA expression of endothelin-A receptor. RESULTS: Compared with the cold stress group, all medication groups showed significant reductions in SBP since week 5 (P<0.05). The cold stress group showed a significant increase in LVWI compared with the control group (3.38±0.27 mg/g vs 2.89±0.19 mg/g, P<0.05). The amlodipine group showed a significant reduction in LVWI compared with the cold stress group (2.98±0.28 mg/g vs 3.38±0.27 mg/g, P<0.05). The cold stress group showed a significant reduction in plasma NO concentration compared with the control group (104.9±19.5 µmol/L vs 129.3±17.8 µmol/L, P<0.05) ; compared with the cold stress group, all the medication groups showed significant increases in blood NO concentration (P<0.05). The cold stress group showed a significant increase in myocardial ET-1 concentration compared with the control group (6.3±1.5 pg/100 mg vs 4.5±1.9 pg/100 mg, P<0.05) ; compared with the cold stress group, the amlodipine group showed a significant reduction in myocardial ET-1 concentration (4.4±1.0 pg/100 mg vs 6.3±1.5 pg/100 mg, P<0.05). The cold stress group had significantly higher mRNA expression of endothelin-A receptor than the control group (0.86±0.23 vs 0.45±0.16, P<0.01) ; compared with the cold stress group, the amlodipine group showed a significant reduction in the mRNA expression of endothelin-A receptor (0.41±0.14 vs 0.86±0.23, P<0.01). CONCLUSION: Amlodipine can reduce the increase in SBP and inhibit LVH in spontaneously hypertensive rats under cold stress.

High-sensitivity cardiac troponin T is a predictor of recurrent acute coronary syndrome in patients with acute myocardial infarction.

High-sensitivity cardiac troponin T is a useful tool for diagnosing myocardial ischemia. However, its role in the prognosis of patients with acute myocardial infarction has not been studied. Here, the prognostic value of high-sensitivity cardiac troponin T for patients with acute myocardial infarction was investigated. The concentrations of high-sensitivity cardiac troponin T, other clinical chemistry makers, and living habits were investigated at the time of admission in patients with acute coronary syndrome, whereas the high-sensitivity cardiac troponin T concentrations at 6 h after admission and during recovery were analyzed in other patient groups. The concentration of high-sensitivity cardiac troponin T was significantly higher in patients with acute myocardial infarction than in those with other cardiac diseases and in controls (P < 0.01). Based on the standard diagnostic criterion, 134 patients were diagnosed with acute myocardial infarction. Monitoring the change in concentration of high-sensitivity cardiac troponin T in patients with acute coronary syndrome can reduce the risk of recurrence and death.

Anti-tumor effect of endostatin in a sleep-apnea mouse model with tumor.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with cancer incidence and mortality. The underlying mechanism is unclear. This study aims to evaluate the influence of intermittent hypoxia (IH), a novel hallmark of OSA, on tumor and to access the anti-tumor effect of endostatin on a mouse model with OSA. METHODS: The C57BL/6 J mice were randomly classified into four groups: control (normoxia) (CTL), control plus endostatin (CTL + ED), IH, and IH plus endostatin (IH + ED). Mice in IH and IH + ED groups were subjected to IH 8 h per day in 5 weeks. Lewis lung cancer cells were injected into the flank of each mouse after 1 week of IH exposure. Endostatin was also intraperitoneally injected after tumor volume reached about 200 mm3. The maximum standard uptake values (SUVmax) were detected by micro-positron emission tomography-computed tomography (micro-PET-CT) imaging prior and post-endostatin administration. Microvessel density (MVD) and vascular endothelial growth factor (VEGF) were determined for evaluating the anti-tumor effect of endostatin among the normoxia and IH conditions. RESULTS: Mice had higher SUVmax in the IH group than the CTL group (p < 0.01). When compared with mice in the CTL group, those in the IH group had significantly greater MVD values (p < 0.001). The SUVmax can be attenuated by endostatin both in the CTL (p < 0.01) and IH conditions (p < 0.001). When compared with CTL group, mice in the IH group had increased MVD values (p < 0.001) and VEGF expression both at mRNA (p < 0.05) and protein levels (p < 0.001 in western blotting results). Treatment with endostatin attenuated serum and tissue VEGF levels, lowering the MVD values. As compared to normoxia condition, the endostatin-therapeutic effects were more significant under the IH condition (p < 0.05 in western blotting results). CONCLUSIONS: Micro-PET-CT imaging is a promising non-invasive technique to evaluate the tumor metabolic characteristics under IH condition in vivo. The anti-tumor effect of endostatin under IH condition is superior to that of the normoxia condition.

The relationship between vascular wall shear stress and flow-mediated dilation: endothelial function assessed by phase-contrast magnetic resonance angiography.

OBJECTIVES: We sought: 1) to investigate the relationship between vascular wall shear stress and flow-mediated dilation (FMD) in humans, and 2) to investigate whether this relationship could explain why FMD is greater in small arteries. BACKGROUND: Arterial wall shear stress (WSS) is considered to be the primary stimulus for the endothelial-dependent FMD response. However, the relationship between WSS and FMD has not been investigated in humans. Furthermore, FMD is greater in small arteries, though the reasons for this phenomenon are unclear. METHODS: Using phase-contrast magnetic resonance angiography (PMRCA), we measured hyperemic WSS and FMD in 18 healthy volunteers. Peak systolic WSS was calculated assuming a blunted parabolic velocity profile. Diameter by PCMRA and by ultrasound was compared in nine subjects. RESULTS: Flow-mediated dilation was linearly proportional to hyperemic peak systolic WSS (r = 0.79, p = 0.0001). Flow-mediated dilation was inversely related to baseline diameter (r = 0.62, p = 0.006), but the hyperemic peak WSS stimulus was also inversely related to baseline diameter (r = 0.47, p = 0.049). Phase-contrast magnetic resonance angiography and ultrasound diameters were compared in nine subjects and correlated well (r = 0.84, p < 0.0001), but diameter by PCMRA was greater (4.1 +/- 0.7 mm vs. 3.7 +/- 0.5 mm, p = 0.009). CONCLUSION: Arterial FMD is linearly proportional to peak hyperemic WSS in normal subjects. Thus, the endothelial response is linearly proportional to the stimulus. Furthermore, the greater FMD response in small arteries is accounted for, at least partially, by a greater hyperemic WSS stimulus in small arteries. By allowing the calculation of vascular WSS, which is the stimulus for FMD, and by imaging a fixed arterial cross-section, thus reducing operator dependence, PCMRA enhances the assessment of vascular endothelial function.

A quantitative study of ramped radio frequency, magnetization transfer, and slab thickness in three-dimensional time-of-flight magnetic resonance angiography in a patient population.

RATIONALE AND OBJECTIVES: The authors compare the effectiveness of various magnetic resonance (MR) angiography acquisition strategies in enhancing the visibility of small intracranial vessels. METHODS: Blood vessel contrast-to-noise ratio (CNR) in time-of-flight MR angiography was studied as a function of vessel size and several selectable imaging parameters. Contrast-to-noise measurements were made on 257 vessel segments ranging in size from 0.3 mm to 4.2 mm in patients who recently had undergone intraarterial cerebral angiography. Imaging parameters studied included magnetization transfer, spatially variable radio frequency (RF) pulse profile (ramped RF), and imaging slab thickness. RESULTS: The combination of thin slabs (16 slices/slab), ramped RF, and magnetization transfer resulted in the highest CNR for all but the smallest vessel sizes. The smallest vessels (< 0.5 mm) had the highest CNR, using the thick slab (64 slices/slab) with ramped RF and magnetization transfer. Magnetization transfer always improved vessel CNR, but the improvement diminished as the slab thickness was reduced. The CNR increased with a decrease in slab thickness for all but the smallest vessel sizes. CONCLUSIONS: Overall, the results provide a quantitative demonstration that inflow enhancement of blood is reduced for small vessels. Thus, whereas magnetization transfer is important at all vessel sizes, it becomes the primary factor in improving the visibility of the smallest vessels.

Evaluation of gradient inhomogeneity in the optimal design of gradient coils.

The image distortion caused by gradient inhomogeneity was derived from the image equation of Fourier MR imaging. A measurement of gradient inhomogeneity was proposed based on the amount of image distortion. Using the proposed measurement of gradient inhomogeneity in the optimal design of a z-gradient coil reduced image distortion by 39-45% compared to a previously used figure of merit in gradient coil design.

Studies on the performance of circular and elliptical Z-gradient coils using a simulated annealing algorithm.

Elliptical z-gradient coils with different ellipticities are optimized using a simulated annealing algorithm. This study demonstrates that when the coil ellipticity was changed from 1.0 to 1.67, the gradient strength was increased by 21% and the coil inductance was reduced by about 34%. At the same time, the gradient inhomogeneity was increased by a factor between 15 to 47%. In these examples we also observed that when the coil ellipticity was increased from 1.0 to 1.11, the gradient inhomogeneity was reduced by a factor between 16 to 19%. This study provides a quantitative assessment of the advantages and disadvantages in coil performance obtained by using elliptical z-gradient coils.

Function and regulation of cholecystokinin octapeptide, beta-endorphin and gastrin in anorexic infantile rats treated with ErBao Granules.

AIM: To study the role of cholecystokinin octapeptide (CCK-8),beta endorphin (beta EP), and gastrin in an anorexic infantile rat model and no subsequent regulation of nose peptides by the Yunpi complex prescription ErBao Granule. METHODS: We fed infantile rats with special prepared forage. A liquid extract of ErBao Granule was administered to the rats daily for 3 weeks, CCK-8, beta-EP, and gastrin concentrations in hypothalamus, gastric antrum, and plasma of the rats were measured by radioimmunoassay, and were compared with controls. RESULTS: Treatment of rats with ErBao Granule inhibited CCK-8 secretion and increased beta-EP and gastrin secretion. CCK-8 concentration in hypothalamus and plasma of model control group increased significantly and correlated negatively with food intake of models, respectively. beta-EP concentration in gastric antrum and plasma of model control group decreased significantly and showed a positive correlation with food intake of models, respectively. Hypothalamus concentration of beta-EP was similar in models and controls. Gastrin concentration in gastric antrum of models was lower than in the blank control group, and correlated positively to food intake of models. Finally, CCK-8 concentrations in plasma of rats showed a positive correlation with plasma beta-EP (r=-0.68, P<0.05). CONCLUSION: The increased plasma and hypothalamus concentration of CCK-8, decreased gastric antrum and plasma level of beta-EP, and decreased gastric antrum concentration of gastrin are associated significantly with the anorexia of infantile anorexic rat models produced by special for-age. ErBao Granule can reverse these changes, which may be the major mechanisms of ErBao Granule simulating feeding.

[Effect of ET-1 antisense oligodeoxynucleotide on the hemodynamics of normal and experimental hypertensive rats].

It was previously found that a phosphorothioated antisense oligodeoxynucleotide (ETASODN) significantly inhibits production of endothelin-1 (ET-1). The purpose of the present study was to determine whether intracerebroventricular injection of ETASODN targeted to prepro-ET-1 is capable of exerting the same preventing effect on the aorta narrowing of experimentally modeled hypertensive rats. Radioimmunoassay showed that ET-1 level in the brain stem of hypertensive rats was significantly elevated. In addition to down-regulating the ET-1 level, astisense could also reduce mean arterial pressure (MAP), heart rate and LVSP in model rats. The antisense also down-regulated the ET-1 level in hypothalamus and brain stem, reducing MAP in normal control rats. After treatment with the antisense, the value of delta MAP was markedly lowered in experimental hypertensive rats as compared to the control ones. Thus it appears that (1) ET-1 might play an important role in central cardiovascular regulation in rats and (2) antisense ETASODN might be used in treatment of hypertension via inhibiting ET-1 production.

Vessel enhancement filtering in three-dimensional MR angiograms using long-range signal correlation.

Small vessels in three-dimensional MR angiograms have low visibility in maximum-intensity projection images because of their low contrast. In a previous study, we had two nonlinear filters that appeared to give significant improvement in small vessel detail. In this paper, we report on a generalization of this filter that allows a more general modeling of the vessels and a more complete suppression of background. One implementation of the general filter gave a vessel mean contrast-to-noise ratio that is 2.52 and 3.51 times higher than the vessel mean contrast-to-noise ratio obtained using our previously reported maximum-minimum (max-min) filter and cross-section filter, respectively.

Optimal design of gradient coils in MR imaging: optimizing coil performance versus minimizing cost functions.

The "forward" method of an optimal gradient coil design provides a coil that has the minimal cost function value. It is shown in this study that the solution obtained by minimizing the cost function is directly dependent on the specified cost function and generally results in a deviation from the most desirable coil design. In this paper, a gradient coil design approach for obtaining the best achievable coil performance for pre-determined imaging applications is presented. Through this approach, all intermediate coil performance values calculated during an optimization process, using a simulated annealing algorithm, are stored and presented in a three-dimensional data set. Using this three-dimensional data set, a coil designer is able to make a balance between different coil performance parameters and to select a coil that is the most desirable for the pre-determined imaging applications.

Vessel enhancement filtering in three-dimensional MR angiography.

For a variety of reasons, small vessels have low signal intensity in magnetic resonance angiography. When the vessel signal intensity is lower than the signal intensity of background tissues, these vessels tend not to be visible on maximum-intensity-projection images. The authors developed a nonlinear second-difference spatial filtering technique that enhances the details of small vessels while suppressing both noise and uniform background tissue. Two similar nonlinear second-difference filters are presented and compared with the linear Laplacian second-difference filter. To evaluate the performance of these filters, they were applied to intracranial three-dimensional time-of-flight MR angiographic data and the results compared with the vessel enhancement obtained with a simple second-difference Laplacian filter and with magnetization transfer contrast (MTC) techniques. The comparisons demonstrated that nonlinear filtering and MTC techniques result in similar improvement in small-vessel visibility and apparent continuity. A quantitative comparison demonstrated that the improvement in the contrast-to-noise ratio is much greater with the nonlinear filters than the Laplacian filter.

Vessel enhancement filtering in three-dimensional MR angiography.

For a variety of reasons, small vessels have low signal intensity in magnetic resonance angiography. When the vessel signal intensity is lower than the signal intensity of background tissues, these vessels tend not to be visible on maximum-intensity-projection images. The authors developed a nonlinear second-difference spatial filtering technique that enhances the details of small vessels while suppressing both noise and uniform background tissue. Two similar nonlinear second-difference filters are presented and compared with the linear Laplacian second-difference filter. To evaluate the performance of these filters, they were applied to intracranial three-dimensional time-of-flight MR angiographic data and the results compared with the vessel enhancement obtained with a simple second-difference Laplacian filter and with magnetization transfer contrast (MTC) techniques. The comparisons demonstrated that nonlinear filtering and MTC techniques result in similar improvement in small-vessel visibility and apparent continuity. A quantitative comparison demonstrated that the improvement in the contrast-to-noise ratio is much greater with the nonlinear filters than the Laplacian filter.

The voxel sensitivity function in Fourier transform imaging: applications to magnetic resonance angiography.

In this paper the problem of small structure visualization in magnetic resonance imaging (MRI) is considered. The relationship between the structure and the image intensities is defined in terms of the voxel sensitivity function (VSF). Using the VSF, the spatial dependence of the voxel signal for small spheres and cylinders is computed. Although the spatial fluctuation is smaller in the MRI VSF than that which would be obtained from a uniformly sensitive cubical voxel, the deviation still results in significant signal loss near the edges and corners of the voxels. Finally, the VSF formalism is used to demonstrate the improvement in signal uniformity that can be obtained by using zero-filled (band-limited or sinc) interpolation.

Advanced cardiac MR imaging of ischemic heart disease.

Important advances in rapid magnetic resonance (MR) imaging technology and its application to cardiovascular imaging have been made during the past decade. High-field-strength clinical magnets, high-performance gradient hardware, and ultrafast pulse sequence technology are rapidly making the vision of a comprehensive "one-stop shop" cardiac MR imaging examination a reality. This examination is poised to have a significant effect on the management of coronary artery disease by means of assessment of wall motion with tagging and pharmacologic stress testing, evaluation of the coronary microvasculature with perfusion imaging, and direct visualization of the coronary arteries with MR coronary angiography. This article reviews current state-of-the-art pulse sequence technology and its application to the evaluation of ischemic heart disease by means of MR tagging with dobutamine stress testing, MR perfusion imaging, and MR coronary angiography. Cutting edge areas of research in coil design and exciting new areas of metabolic and oxygen level-dependent imaging are also explored.

Reduction of partial-volume artifacts with zero-filled interpolation in three-dimensional MR angiography.

Partial-volume artifacts reduce vessel contrast and continuity (especially in small vessels) in magnetic resonance (MR) angiography. The authors applied zero-filled (band-limited) interpolation to three-dimensional (3D) MR angiograms to reduce partial-volume artifacts. They demonstrated that zero-filled interpolation can also be implemented by means of voxel shifting in real space. Voxel-shifted interpolation is much less computer memory intensive than conventional zero-filled interpolation. They numerically simulated the contrast loss due to partial-volume artifacts and contrast recovery obtained with zero-filled interpolation. Zero-filled interpolation in all three orthogonal directions was applied to 3D MR angiography data sets from 29 human studies. These studies were obtained with the three commonly used 3D MR angiography techniques: 3D time of flight, multislab 3D time of flight, and 3D phase contrast. A substantial improvement in vessel contrast and vessel continuity was observed in all cases.