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This paper studies the active force characteristics of the neck muscles under the condition of rapid braking, which can provide theoretical support for reducing the neck injury of pilots when carrier-based aircraft blocks the landing. We carried out static loading and real vehicle braking experiments under rapid braking conditions, collected the active contraction force and electromyography (EMG) signals of neck muscles, and analyzed the response characteristics of neck muscle active force response. The results showed that the head and neck forward tilt time was delayed and the amplitude decreased during neck muscle pre-tightening. The duration of the neck in the extreme position decreased, and the recovery towards the seat direction was faster. The EMG signals of trapezius muscle was higher than sternocleidomastoid muscle. This suggests that pilots can reduce neck injury by pre-tightening the neck muscles during actual braking flight. In addition, we can consider the design of relevant fittings for pre-tightening the neck muscles.
Subject(s)
Neck Muscles , Neck , Electromyography , HeadABSTRACT
Objective:To compare the clinical characteristics and analyze the prognostic factors between human immunodeficiency virus (HIV)-infected patients and non-HIV-infected immunocompromised patients with pneumocystis pneumonia (PCP) complicated with acute respiratory failure (ARF) in intensive care unit (ICU).Methods:The clinical data of patients with PCP complicated with ARF admitted in ICU of The First Affiliated Hospital of Zhengzhou University and The Sixth People′s Hospital of Zhengzhou City between May 2018 and October 2020 were retrospectively reviewed. All subjects were divided into HIV-infected group and non-HIV-infected immunocompromised group. General characteristics and underlying diseases of patients in the two groups were analyzed. Laboratory parameters, treatment and outcomes between two groups were compared. Independent sample t test, Mann-Whitney U test and chi-square test were used for statistical analysis, and univariate and multivariate logistic regression models were used to identify the risk factors for the clinical outcome. Results:A total of 129 PCP complicated with ARF patients were enrolled, including 75 HIV-infected patients and 54 non-HIV-infected immunocompromised patients. Only 10.7%(8/75) patients of HIV-infected group received anti-retroviral therapy (ART), but none of the patients in either groups had previously received trimethoprim-sulfamethoxazole (TMP-SMX) for PCP prophylaxis. Acute physiology and chronic health evaluation (APACHE) Ⅱ score of HIV-infected group was 18.7±6.0, which was higher than that in non-HIV-infected immunocompromised group (13.1±4.4) when admitted in ICU ( t=-5.45, P<0.001). Hypoproteinemia was common in both groups. Ninety-six percent (72/75) of HIV-infected patients had CD4 + T lymphocyte counts lower than 200/μL and 84.0%(63/75) of patients had CD4 + T lymphocyte counts even lower than 50/μL, while 5.74%(31/54) of patients in non-HIV-infected immunocompromised group had CD4 + T lymphocyte counts lower than 200/μL. The CD4 + /CD8 + T lymphocyte counts ratio was 0.05(0.02, 0.12) in HIV-infected group, which was lower than that in non-HIV-infected immunocompromised group (0.96(0.64, 1.44)), and the difference was statistically significant ( Z=-9.16, P<0.001). The length of ICU stay and hospital stay of non-HIV-infected immunocompromised patients were 10.0(7.0, 14.0) days and 18.0(11.8, 32.5) days, respectively, which were both longer than those in HIV-infected patients (7.0(4.0, 9.0) days and 13.0(7.0, 23.0) days, respectively), and the differences were both statistically significant ( Z=-3.58 and -2.73, respectively, both P<0.050). The hospital mortality of HIV-infected patients was 57.3%(43/75), which was significantly higher than that in non-HIV-infected immunocompromised patients (38.9%, 21/54) ( χ2=4.27, P=0.039). Multivariable logistic regression identified that lactic dehydrogenase (LDH), C-reactive protein (CRP) and APACHE Ⅱ score were the risk factors for the clinical outcome of HIV-infected patients (odds ratio ( OR)= 1.006, 1.015 and 1.736, respectively, all P<0.050). The partial pressure of oxygen in arterial blood/fractional concentration of inspiratory oxygen (PaO 2/FiO 2), LDH and CD4 + T lymphocyte counts were the risk factors for the clinical outcome of non-HIV infected immunocompromised patients ( OR=0.970, 1.008 and 0.989, respectively, all P<0.050). Conclusions:PCP patients with ARF are critically ill with high mortality rate. LDH, CRP and APACHEⅡscore are predictors for prognosis of HIV-infected patients with PCP, while PaO 2/FiO 2, LDH and CD4 + T lymphocyte counts are predictors for prognosis of non-HIV infected immunocompromised patients with PCP.
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Objective@#To investigate the expression levels and clinical significance of serum miRNAs, including miR-146a-5p, miR-155-5p and miR-124a-3p, in patients with rheumatoid arthritis (RA). @*Methods@#The clinical data, whole blood and serum samples from 39 RA patients hospitalized in our hospital during October 2016 and October 2018 were collected. Whole blood specimens were used to determine erythrocyte sedimentation rate (ESR), and serum samples were used to detect rheumatoid factor (RF), C-reaction protein (CRP) and miRNAs. The expression levels of serum miR-146a-5p, miR-155-5p and miR-124a-3p in RA patients were detected by SYBR Green real-time fluorescence quantitative PCR. @*Results@#The expression levels of serum miR-146a-5p (1.742±1.058) in RA patients before treatment were significantly higher than that in healthy controls (HC, 1.045±0.772), which were positively correlated with DAS28 scores (r=0.836 5,P=0.004 5), ESR (r=0.437 2, P=0.032 5) and RF levels (r=0.733 6,P=0.013 7). However, the expression levels of serum miR-155-5p (U=42.00,P=0.032 9) and miR-124a-3p (U=44.5,P=0.044 5) in RA patients were significantly lower than that in HC, and the expression levels of serum miR-155-5p were negatively correlated with RF levels (r=-0.445 3,P=0.031 6), and the expression levels of serum miR-124a-3p were negatively correlated with DAS28 scores (r=-0.538 7,P=0.025 8) and RF levels (r=-0.436 5,P=0.046 3). After treatment, the expression levels of serum miR-146a-5p (U= 60.00,P=0.003 8) in RA patients were significantly decreased, while the expression levels of serum miR-155-5p (U=64.00,P=0.005 9) and miR-124a-3p (U=85.00,P=0.042 2) were significantly increased. @*Conclusion@#The abnormal expression levels of serum miR-146a-5p, miR-155-5p and miR-124a-3p in RA patients have potential clinical significance for the diagnosis of RA.
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<p><b>OBJECTIVE</b>To characterize the expressions of peroxiredoxin 1 (Prx1), peroxiredoxin 6 (Prx6) and glial fibrillary acidic protein (GFAP) in human brain astrocytoma and explore their clinical significance.</p><p><b>METHODS</b>The protein and mRNA expression levels of Prx1, Prx6 and GFAP in human brain astrocytoma and normal brain tissue specimens were determined by Western blotting, RT-PCR and immunohistochemistry.</p><p><b>RESULTS</b>The protein and mRNA expressions of Prx1 and Prx6 increased significantly in the order of normal brain tissue, grade II astrocytoma, grade III astrocytoma and grade IV astrocytoma (P<0.05). The protein and mRNA expressions of GFAP decreased significantly in grade III and IV astrocytoma compared with those in grade II astrocytoma and normal brain tissues (P<0.05).</p><p><b>CONCLUSION</b>Prx1 and Prx6 may play important roles in the invasion and malignant development of human brain astrocytoma, and may serve as biomarkers for evaluating the invasiveness, malignancy and prognosis of the tumor as well as potential molecular targets in astrocytoma therapy.</p>
Subject(s)
Adolescent , Adult , Aged , Child , Child, Preschool , Female , Humans , Male , Middle Aged , Young Adult , Astrocytoma , Metabolism , Pathology , Brain Neoplasms , Metabolism , Pathology , Glial Fibrillary Acidic Protein , Metabolism , Peroxiredoxin VI , Metabolism , Peroxiredoxins , MetabolismABSTRACT
Objective To determine the effect of GnRH Ⅰ and GnRH Ⅱ on the secretion of VEGF by eutopic and ectopic endometrial stromal cells cultured in vitro, and to provide theoretical basis for exploring new treatments for endometriosis (EMs).Methods Eutopic and ectopic endometrium stromal cells cultured in vitro were treated with different concentrations of GnRH Ⅱ and a GnRH I(goserelin), and a control group was not treated by GnRH Ⅱ and GnRH Ⅰ. Enzyme linked immunosorbent assay (ELISA) was used to measure the content of vascular endothelial growth factor (VEGF) protein in the medium of the above 2 groups.Results (1)There was no difference in the VEGF protein secreted by eutopic and ectopic stromal cells in the medium after being cultured in vitro for 48 h (P＞0.05).(2)10-10, 10-8, and 10-6mol/L GnRH Ⅱ dose-dependently reduced VEGF protein secreted by endometrial stromal cells (P＜0.05),and the inhibition effect was stronger than that of GnRH Ⅰ (P＜0.05).(3)The inhibition effect of GnRH Ⅱ on VEGF in ectopic stromal cells was stronger than that of eutopic stromal cells (P＜0.05).Conclusion (1)Ectopic stromal cells cultured in vitro can secrete VEGF,which has no difference from the eutopic stromal cells, and which may play an important role in the formation and development of EMs.(2)GnRH Ⅱ can dose-dependently reduce VEGF protein secreted by ectopic and eutopic endometrial stromal cells cultured in vitro,and the inhibition effect is stronger than that of GnRH Ⅰ, providing theoretical basis for exploring new treatments for EMs.
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OBJECTIVE@#To inspect the effect of gonadotropin-releasing hormonel II (GnRH-II)on the secretion of VEGF by eutopic and ectopic endometrial stromal cells cultured in vitro.@*METHODS@#Eutopic and ectopic stromal cells cultured in vitro were treated with different concentrations (1x10(-10) - 1x10(-6) mol/L) of GnRH-II,and the control group was not treated by GnRH-II.Enzyme-linked immunosorbent assay (ELISA) was used to measure the VEGF protein in the medium of the above 2 groups.@*RESULTS@#There was no difference between the VEGF protein expressed by eutopic and ectopic stromal cells in the medium after culturing in vitro for 48 hours (P>0.05). The 1x10(-10) - 1x10(-6) mol/L GnRH-II could dose-dependently reduce VEGF protein secreted by endometrial stromal cells (P<0.01), and the inhibition to ectopic endometrial stromal cells was stronger than that to eutopic endometrial stromal cells (P<0.01).@*CONCLUSION@#Ectopic stromal cells cultured in vitro can secrete VEGF, and so can eutopic stromal cells. This may play an important role in the formation and development of endometriosis. GnRH-II can reduce VEGF protein secreted by ectopic endometrial stromal cells cultured in vitro, and its inhibition is stronger than that of eutopic endometrial stromal cells.