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Objective Based on the dummy model, to study the relationship between different backrest angles and neck injuries under the effect of horizontal negative acceleration (-Gx ). Methods The dummy model was fixed on the base of the acceleration platform facing the orbital direction, and the backrest angle was set at 17°, 22°, 30°, respectively. Each experimental group performed 10 repeated tests according to the same acceleration curve, differences between the upper and lower acceleration of the cervical spine under the same -Gx conditions were compared, and the neck injury criteria (NIC) was calculated and compared through curve fitting. Results The time-acceleration curves of the upper and lower cervical spine in the anteroposterior and vertical directions had the same shape with peak differences. In the anteroposterior direction (X-axis), the acceleration peak of the 22° backrest angle experimental group was slightly higher than that of 17° and 30° backrest angle experimental groups, but in the vertical direction (Z-axis), the acceleration peak of the 22° backrest experimental group was lower than that of 17° and 30° backrest angle experimental groups. In the anteroposterior and vertical directions, the NICmax measured by 22° backrest angle experimental group was relatively smaller, NICmax measured by 30°backrest angle experimental group was in the middle, and NICmax measured by 30° backrest angle experimental group was relatively larger. Conclusions There was a nonlinear relationship between the backrest angle and theneck injury. The neck injury of the dummy model with the backrest angle of 22° was smallest under the effect of-Gx in this experiment.
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Objective To compare the differences of neck injury risks for different mummies during arrested landing on naval vessels. Methods Based on the established dynamic model of dummy-belt-seat systems and mechanical model of head-neck, with the acceleration curve at seat base during typical arrested landing reported in the literature as the input, numerical simulation was conducted to test the validity of the model, and the axial force, shear force， bending moment of typical joints in dummy neck during arrested landing were obtained. Results The injury index Nkm of 95 percentile dummy was higher than that of 5 percentile dummy. The injury index Nij of the dummy’s upper and lower cervical spine was smaller than 0.2, meanwhile the Nkm was around 0.65. Conclusions During arrested landing, human neck was much easier to get hurt due to the shear force. The research findings can provide data support for evaluating neck injury risks of pilots with different sizes during typical arrested landing process.
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Objective To investigate the correlation between atorvastatin inhibiting Interleukin-1β(IL-1β) expression and peroxisome proliferator activated receptor β/δ (PPARβ/δ) signal channel in myocyte of aging rat. Methods Primary culture of myocyte were got from aging rat. Myocyte were divided into control group, DMSO group, atorvastatin group, atorvastatin plus GSK0660 group, whichwere treated respectively by Cell culture medium, dimethyl sulfoxide (DMSO), atorvastatin, atorvastin plus GSK0660. The expression level of IL-1βmRNA and protein was evaluated by RT-PCR and Western Blot respectively. Results (1)NO difference were found between control group and DMSO group in expression level of IL-1βmRNA and protein (P>0.05);(2)The expression level of IL-1βmRNA and protein in atorvastatin group were significantly lower than those of control group (P < 0.01); (3)Both mRNA and protein expression level of IL-1βin atorvastatin plus GSK0660 group were higher than those of atorvastatin group(P<0.05 or P<0.01), but still lower than those of control group(P<0.05). Conclusions Atorvastatin down-regulate the expression of IL-1βin aging myocytes by activating PPARβ/δsignal Channel.
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The wavelength of infrared rays,beyond that of red visible light in optical spectre,ranges from 0.76 to 1000.00 μm.In clinic,infrared rays include a near-infrared part(with the wavelength ranging from 0.76 to 1.5μm)and a far-infrared part(with the wavelength ranging from 1.5 to 400μm).The far-infrared rays,having a wavelength ranging from 6 to 14 μm,are critical for human health and lives.The far-infrared rays have many biological functions including extending blood capillary,increasing blood flow,enhancing metabolism and repair,accommodating organism disequilibrium,etc.The main biological effect of far-infrared rays is cell activation which can induce a senes of biochemistry and histochemistry changes of calls.With the help of far-infrared rays,human body can be in a healthy status.The main clinical applications of far-infrared rays include auxiliary diagnosis,softening inflammation and pain.tissue repair,sterilization,tumor depression,rewarming from hypothermia,and so on.Far-infrared rays play active functions on human body through caloric effects.Now they are developed to be applied in partial medical fields.The emphases of the future studies are about the effects of far-infrared rays based on molecular biology researches and about the extensive applications of far-infrared rays in medicine.
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BACKGROUND: Angiotensin Ⅱ (Ang-Ⅱ) can stimulate vascular endothelial cells to excrete endothelin, a kind of potent vasoconstrictor. The content of endothelin in blood or cell culture media directly reflects the function and injured status of vascular endothelial cells. Therefore, it is significant for strengthening vascular endothelial cells to resist the injured factors. Tea polyphenols is a mainly active component of tea, and it is considered as a reagent for anti-atherosclerosis, protecting injuries of vascular endothelial cells and preventing cardiovascular diseases. OBJECTIVE: To observe the effects of tea polyphenols in different concentrations on endothelin content in vascular endothelial cells induced by Ang-Ⅱ at various time points through establishing Ang-Ⅱ-induced vascular endothelial cell injury models and further to investigate the protective effect of tea polyphenols on vascular endothelial cells. DESIGN: Observational study.SETTING: Aerospace and Diving Medical Center, Navy General Hospital of Chinese PLA.MATERIALS: The experiment was carried out in Laboratory of Aerospace and Diving Medical Center, Navy General Hospital of Chinese PLA from March to September 2005. Main materials were detailed as follows: Ang-Ⅱ (Sigma Company), tea polyphenols (Department of Tea Science, Zhejiang University) and vascular endothelial cells (human large artery vascular endothelial cell system, CBI Company, USA).METHODS: Cultured vascular endothelial cells were divided into 4 groups: ① Control group: The normal culture media was added in the isopyknic vascular endothelial cells, and 100 μL supernatant was extracted before and at 0.5, 6 and 24 hours after filling moisturized liquid. ② Ang-Ⅱ group: Cell culture media containing 10-7 mol/L Ang-Ⅱ was added in the vascular endothelial cells, and other operations were as the same as those in the control group. ③ High-concentration tea polyphenols + Ang-Ⅱ group: Cell culture media containing 50 mg/L tea polyphenols was added in the vascular endothelial cells, and other operations were as the same as those in the Ang-Ⅱ group. ④ Low-concentration tea polyphenols + Ang-Ⅱ group: Cell culture media containing 25 mg/L tea polyphenols. 100 μL supernatant was extracted before and after 0.5, 6 and 24 hours treatment in each group. Thereafter, radioimmunoassay was used to measure the content of endothelin. MAIN OUTCOME MEASURES: Content of endothelin.RESULTS: ① Content of endothelin in Ang-Ⅱ group was higher than that in the control group (P ＜ 0.01). ② At 6 and 24 hours after high-concentration tea polyphenols incubation, content of endothelin in high-concentration tea polyphenols + Ang-Ⅱ group was lower than that in Ang-Ⅱ group (P ＜ 0.01). Moreover, the content of endothelin in low-concentration tea polyphenols + Ang-Ⅱ group was lower than that in both high-concentration tea polyphenols + Ang-Ⅱ group and angiotensin Ⅱ group (P ＜ 0.01). CONCLUSION: Tea polyphenols has inhibitory effects on endothelin releasing function of vascular endothelial cells induced by Ang-Ⅱ, suggesting that tea polyphenols has protective effect on vascular endothelial cells, and the effect of low-concentration tea polyphenols is superior to that of the high-concentration one.
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Objective To observe changes of expression level of HSP70 protein in rat hippocampus after exposure to +Gz of different magnitudes and to investigate the machanism of HSP70 protein induced by +Gz exposure.Method One hundred rats were divided into: control group,+2 Gz group,+6 Gz group and +10 Gz group.The experimental rats were exposed to +2 Gz,+6 Gz and +10 Gz for 3 min respectively.The rats were killed 6 h,1 d,2 d,4 d,6 d after exposure and brain specimens were made for examination under microscope.The changes of HSP70 protein expression level were determined with immunohistochemical technology.Result The HSP70 protein expression level in the 3 experimental groups were significantly higher than that in control group.It began to rise 6 h after exposure,reached the peak after 1 d,and resumed to normal 6 d after exposure.The expression level was the highest in +6 Gz group and the lowest in +10 Gz group.Conclusion +Gz exposure can induce obvious changes of HSP70 protein expression level and the most prominent changes are found in rats after exposure to +6 Gz group.
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Objective To determine the effect of heat and noise on erythrocyte memb rane ATPase activities in pilots during flying. Method Twenty- four pilots per forming bombing for 3h (45～53℃, 122～97dB in the cabin) served as the su bjects . 21 ground personnel served as control (27℃ in the room). Blood samples were t aken from both groups before flying (6:00 a.m), and immediately (12:00 a.m.) and 8h (8:00 p.m.) after flying. Na+-K+ATPase, and Ca2+-Mg2+ATPase activities in erythrocyte membran e were determined with colorimetry. Result The Na+-K+ATPase activity in eryth rocyte membrane at 6:00 a.m.in pilots was higher than that in control group at the s ame time (P<0.01). The Ca2+-Mg2+ATPase activities in erythrocyte membrane at 12:00 a .m. and 8:00 p.m. in pilots were significantly higher, compared with those in co ntrol group at the same time (P<0.01). Conclusion The ATPase values obtained in our study were all within normal range, and the daytim e variation of both groups are the same. Exposure of human body to heat and noi se for long time may be harmful, the higher ATPase activity is, the more catabol ism of ATP will be. ATP exhaustion will lead to Ca2+ overload in erythrocy te thus stiffen the red cell membrane.