Some aspects of road traffic injuries.
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Accidents, Traffic↗
Biomedical subjects
Zhengguo Wang
Publications and source records attributed to Zhengguo Wang.
[Changes of subtype T lymphocytes in blood after implanting with xenogeneic acellular bone matrix].
OBJECTIVE: To observe the changes of immune status in recipient after implanting with xenogeneic acellular bone matrix (ACBM). METHODS: Twenty rabbits were randomly divided into 4 groups. Autograft, ACBM and bone soaked in alcohol were implanted into the 3 experimental groups separately, and No-treatment was done as control group. The CD4+, CD8+, CD25+ T lymphocytes in blood were detected by flow cytometer at 1, 2, 4 and 6 weeks after operation. After 2 and 6 weeks of implantation, the changes of bone and tissue were observed by histology. RESULTS: After 2-6 weeks, CD4+ and CD8+ T cells were significantly higher in the implanted group of bone soaked in alcohol than that in the other 3 groups (P < 0.05) and there was no statistically significant difference in the other 3 groups (P > 0.05). After 2 weeks, CD25+ T cells were significantly higher in the implanted group of bone soaked in alcohol than that in the other groups. In the 2nd week, there were inflammatory infiltration with a predominance of granulocytes. In the 6th week, there were many fibroblasts instead of granulocytes with a few lymphocytes and cartilage island formed in the implanted groups of autograft and ACBM. CONCLUSION: ACBM implanting has low influence on cellular immunity in recipient.
Animals↗
[Mechanical response numerical analysis of bone tissue based on liquid saturated biphasic porous medium model].
A biphasic porous medium model based on the mixture theory in continuum mechanics frame was used to depict the distributions of osseous stress field, distortion field and pore pressure when the bone tissue was subject to various dynamic loads. In the model, the bone tissue was considered as a transversely isotropic, liquid saturated porous material. The coupling relationship among the distortion, fluid flow and the streaming potential is studied. The Galerkin weighted residual method was used to derive the finite element formulation for dynamic response and the streaming potential calculating formulation of bone tissue, the penalty finite element formulation was obtained via introducing the ratio term of pressure p and penalty parameter beta in the continuity equation and, in turn, eliminated the pressure term in governing equation sets. The computational results show that the viscoelastic behavior and the energy dissipation property in the bone tissue, especially in the cancellous bone, is caused to a great extent by the pore liquid flow and diffusion. Meanwhile, because of the existence of electrical double layer between the solid phase and liquid phase, when the liquid constituents in the pore diffuse, the streaming potential appears, and the growth and absorption of bone tissue is expedited.
Biomechanical Phenomena↗
An overview of research advances in road traffic trauma in China.
With rapid development of social economies, road traffic accidents (RTAs) have continued to increase, and have become the "primary public hazard" to humans. Road traffic trauma (RTT) is a major cause of death in young people of all motorized countries. This article reviews the current advances in RTT research, in order to find some approaches to improving traffic administration and reducing RTAs and RTT. All available data were collected from government, literature, our own research, and conference proceedings. Statistical analysis from every country showed that human factors were still the main cause of RTAs, accounting for more than 90%. Vehicle and road factors caused 3-5% and less than 2% of the total RTAs, respectively. Approximately 85% of RTAs were caused by 21 to 45-year-olds. About 50% of deaths due to RTAs in the United States were related to drinking. In China, RTAs due to driver drinking accounted for 0.29-1.48%. About 6-8% of drivers were prone to RTA, causing 30-40% of RTAs. Seat belts are an effective way to prevent casualties, reducing mortality and morbidity by 13-50%. In China, about 70% of RTAs were related to bicycles. Prehospital emergency treatment is very important. About 35% of deaths may be avoided if the injured receive early and effective treatment. From 1983 to 1992 the mortality of RTT increased by 13% in 18 developing countries, while it decreased by 18% in 13 developed countries, indicating the importance of comprehensive treatment of traffic administration. In addition many advances have been made in basic scientific research of RTT, such as development of serial bioimpact machines and investigation of biomechanical and biochemical mechanisms of impact injuries. In this century, RTAs and RTT are predicted to continue to increase in many countries, especially in developing ones. Full cooperation and comprehensive treatment should be performed in order to improve traffic safety.
Accidents, Traffic↗
Effects of subconvulsive electrical stimulation to the hippocampus on emotionality and spatial learning and memory in rats.
OBJECTIVE: To observe the effects of repeated subconvulsive electrical stimuli to the hippocampus on the emotional behavior and spatial learning and memory ability in rats. METHODS: One hundred and eight male Wistar rats were randomized into 3 groups. Animals in group SE (n = 42) were given subconvulsive electrical stimulation to the hippocampus through a constant pulsating current of 100 mu A with an intratrain frequency of 25 Hz, pulse duration of 1 millisecond, train duration of 10 seconds and interstimulus interval of 7 minutes, 8 times a day, for 5 days. In the electrode control group or CE group (n = 33), animals were implanted with an electrode in the hippocampus, but were not stimulated. Group NC (n = 33) animals received no electrode or any stimulation. The emotional behavior of experimental rats was examined by activity in an unfamiliar open field and resistance to capture from the open field, while the spatial learning and memory ability was measured during training in a Morris water maze. RESULTS: The stimulated rats tested 1 month after the last round of stimulation displayed substantial decreases in open field activity (scale: 10.4 +/- 2.3, P < 0.05) and increases in resistance to capture (scale: 2.85 +/- 0.56, P < 0.01). The amount of time for rats in group SE to find the platform (latency) as a measurement for spatial bias was prolonged (29 +/- 7) seconds after 15 trials in the water maze, P < 0.05). The experimental rats swam aimlessly in all four pool quadrants during the probe trial in the Morris water maze. CONCLUSIONS: Following repeated subconvulsive electrical stimuli to the hippocampus, rats displayed long-lasting significant abnormalities in emotional behavior, increased anxiety and defensiveness, enhanced ease to and delayed habituation to startlement, transitory spatial learning and memory disorder, which parallels many of the symptoms in posttraumatic stress disorder patients.
Animals↗
[Expressions of Ca(2+)/calmodulin-dependent protein kinases cascades in hippocampi of rats with posttraumatic stress disorder-like behavior].
OBJECTIVE: To explore the neurobiological bases in the pathogenesis of lasting emotional behavioral disorders following posttraumatic stress disorder (PTSD). METHODS: 224 male Wistar rats were divided randomly into 3 groups. Group SE included 88 experimental rats the hippocampi of which underwent electrode implantation and subconvulsive stimulation by constant pulsating current of 100 microA with intratrain frequency of 16 Hz, pulsating duration of 1 ms, train duration of 10 s, and interstimulus interval of 7 min 8 times per day for 5 days so as to induce PTSD-like behavior. Group CE included 88 rats the hippocampi of which underwent electrode implantation and without stimulation to be used as controls. Group NC included 48 rat used as normal controls. Twelve, twenty-four, forty-eight, and seventy two hours after subconvulsive stimulation a certain number of rats in the three groups were killed and their hippocampi were taken. The intracellular free calcium, free calmodulin (CaM), and total CaM, Ca(2+)/CaM dependent kinase II alpha(CaMKIIalpha) and IV (CaMKIV) in hippocampi were examined by fluorescence spectrophotometer, flow cytometry, and Western blotting respectively. RESULTS: The intracellular free calcium level in the experimental rats reached the peak 24 hours after subconvulsive stimulation (487.34 +/- 117.93 nmol/L, P < 0.01), and was still elevated 72 hours after the stimulation (289.46 +/- 69.45 nmol/L, P < 0.05). while the mean channel fluorescence of intracellular free CaM decreased remarkably synchronously (1.46 +/- 0.36, P < 0.01, and 2.53 +/- 0.62, P < 0.05, 24 hours and 72 hours after the stimulation respectively). The expression of total CaM 48 hours after the last stimulation in hippocampi of Group SE rats was significantly elevated (P < 0.01), as well as the expression of CaMKIV (P < 0.05). However the expression of CaMKIIalpha was markedly decreased (P < 0.01) 48 hours after-stimulation. CONCLUSION: The lasting dysfunction of Ca(2+)-CaM-CaMKIIalpha/CaMKIV signaling cascades in hippocampus may play an important role in the long-term neuropsychological sequelae in rats with PTSD-like behavior.
Animals↗
[Expression and localization of Nogo-A mRNA in rat nerve tissue].
OBJECTIVE: To investigate the expression and localization of Nogo-A mRNA in brain, spinal cord, optic nerve, and sciatic nerve. METHODS: Frozen sections of brain, spinal cord, optic nerve, and sciatic nerve of 8 rats were made. In situ hybridization was conducted and the sections were observed by light microscopy. RESULTS: The expression of Nogo-A mRNA was positive in brain, spinal cord, and optic nerve, and negative in sciatic nerve. CONCLUSION: The expression of Nogo-A mRNA is negative in brain, spinal cord, and optic nerve, which may be related to the poor axon regeneration in central nervous system.
Animals↗
Toll-like receptor 4, a novel signal transducer for lipopolysaccharide.
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Animals↗
Lipopolysaccharide upregulates the expression of Toll-like receptor 4 in human vascular endothelial cells.
OBJECTIVE: To investigate the expression of Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4) and the effect of lipopolysaccharide (LPS) on their expression in cultured endothelial cells. METHODS: Total RNA was extracted from ECV304 cells and isolated human umbilical vein endothelial cells (HUVECs) exposed to LPS, respectively. The quantification of TLR2 and TLR4 mRNA in HUVECs and EVC304 cells was carried out by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: ECV304 cells and HUVECs were able to express TLR2 and TLR4 mRNA, but the expression levels of TLR4 appeared to be stronger than those of TLR2. LPS could upregulate the expression levels of TLR4 obviously, whereas it had no effect on the expression level of TLR2. CONCLUSIONS: Our data indicate that TLR4 may be the LPS signal transducer in endothelial cells and plays important roles in the cell activation of LPS. The ECV304 cell line is a better experimental model than isolated HUVECs in the research of endothelial cells.
Cell Line↗
Expression of positive and negative regulators of cell cycle during wound healing.
OBJECTIVE: To detect the expression of cell cycle positive regulators cyclin D(1), cyclin E, CDK(2), CDK(4) and negative regulators p21(cip1), p27(kip1), p16(ink4a) and p15(ink4b) during wound healing in rats. METHODS: Open wounds of full-thickness skin, diameter 1.8 cm, on rat backs were used as the wound model. Wound tissues were harvested on postwounding days 3, 5, 7, 9, 11, 14, 21 and 30. Ki67 expression in granulation tissue was detected by immunohistochemical assay. The patterns of the expression of cyclin D(1), cyclin E, CDK(2), CDK(4) and p21(cip1), p27(kip1), p16(ink4a), p15(ink4b) were detected by Western blot. RESULTS: Cell proliferation in granulation tissue took place predominantly within the first week after injury, with the proliferation peak occurring at postwounding day 5. There were no dramatic variations in the expression of cyclin D(1), CDK(2) and CDK(4) during wound healing. Up-regulated cyclin E was maintained from day 3 to 11 after injury, and then was down-regulated. No expression of p16(ink4a) and p15(ink4b) was found. p21(cip1) was expressed only from day 7 to 14, with peak expression observed on day 9. Constitutive p27(kip1) was expressed throughout wound healing with low levels in the proliferating period of day 3 to 5 and with increased levels in the post-mitotic and remodeling stage. The expression of p21(cip1) and p27(kip1) showed an inverse gradient to that of Ki67. CONCLUSION: p21(cip1) and p27(kip1) play a supervising role in preventing the hyperproliferative tendency in tissue repair.
Animals↗
Effect of hypertonic saline solution on the left ventricular functions of isolated hearts from burned rats.
OBJECTIVE: To study the effect of hypertonic saline solution on the left ventricular functions of isolated hearts from burned rats. METHODS: Thirty-six Wistar rats were used and divided into 4 groups: (1) normal hearts perfused with isotonic Krebs-Henseleit solution; (2) normal hearts perfused with Krebs-Henseleit solution which contained 215 mmol/L Na+; (3) hearts of rats suffered from 25% TBSA third degree burn and perfused with isotonic Krebs-Henseleit solution; (4) hearts of the burned rats perfused with Krebs-Henseleit solution which contained 215 mmol/L Na+. The systolic and diastolic functions of the left ventricle were observed. RESULTS: During perfusion, there were very short periods of decrease in heart systolic and diastolic functions at first, but they recovered very soon and even became stronger than normal both in the normal and burned rats. The systolic and diastolic functions of the hearts increased very significantly when the perfusion solution was changed to isotonic solution from the hypertonic solutions. The effect of the hypertonic saline solution on the ventricular systolic and diastolic improvements was stronger in the hearts of the burned rats than that in the normal hearts. CONCLUSIONS: Hypertonic saline solution can directly affect myocardium and significantly improve the ventricular systolic and diastolic functions, especially in the hearts of the burned rats.
Animals↗
Early changes and rules of cardiac function and hemodynamics in rabbits with experimental myocardial contusion.
OBJECTIVE: To study changes and rules of the left ventricular functions in rabbits with myocardial contusion through parallel functional analysis by using echocardiography combined with cardiac catheter intervention. METHODS: Thirty healthy rabbits were selected and impacted to make moderate or severe myocardial contusion by BIM-II biomedical impact machine. The changes of hemodynamics and cardiac systolic and diastolic functions were respectively observed before injury and 1, 4, 8 and 24 hours after injury. RESULTS: After myocardial contusion, the heart rate, systolic pressure, diastolic pressure and mean arterial pressure of rabbits decreased remarkably at 1-4 hours. The left ventricular end systolic pressure (LVESP), the maximum increasing rate of the left intraventricular pressure (+dp/dtmax), isovolumic pressure (IP) and the maximum systolic velocity of the left ventricle (Vmax) also decreased markedly. And then these parameters recovered to the level of preinjury at 8-24 hours. The left ventricular end-diastolic pressure (LVEDP), the rate of the left intraventricular pressure (-dp/dtmax) and the decreasing time constant of the left intraventricular pressure (T) increased remarkably 1 hour after myocardial contusion, and did not decrease until 8 hours after myocardial contusion. Detection by echocardiography showed that ejection fraction of the left ventricle markedly decreased at 24 hours after myocardial contusion, while the systolic volume decreased obviously as early as 1 hour after myocardial contusion, at 4-8 hours it recovered a little and again decreased at 24 hours. The end systolic volume and end diastolic volume increased after myocardial contusion, but statistical significance was only seen at 8 hours after myocardial contusion. CONCLUSIONS: Cardiac functions of the left and right ventricles are markedly injured after myocardial contusion with disorders of the left ventricle diastolic function and of the right ventricle systolic function as the dominant injury. While the systolic function of the left ventricle can recover. Echocardiography shows clinical importance in detection of early injuries of cardiac functions.
Animals↗
Effect of substance P released from peripheral nerve ending on endogenous expression of epidermal growth factor and its receptor in wound healing.
OBJECTIVE: To explore the relationship between substance P (SP) released from peripheral nerve endings and the expression of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) during wound healing. METHODS: Fifty Wistar rats were randomly divided into 2 groups, injury group and capsaicin group. In the injury group, a full-thickness skin wound on the back of the rat was taken. The wound edge and granulation tissues were taken on the 1st, 3rd, 6th, 9th, 12th days after injury, respectively. In the capsaicin group, capsaicin was injected subcutaneously on the back of the rats to destroy the sensory nerve to prevent the secretion of SP, then a wound and sample was made in the same way. Immunohistochemistry and in situ hybridization were employed to detect the expression of SP, EGF/EGFR, and EGF mRNA/EGFR mRNA in the granulation tissues. RESULTS: In the injury group, immunohistochemical stain of SP and EGF/EGFR was located on the hair follicles and sebaceous glands at the 1st day. And the stain of SP was obvious at the 3rd day in the granulation tissues, then decreased gradually. EGF/EGFR was at low level at the 3rd day, then increased gradually and reached the peak at the 9th day, then declined. In the capsaicin group, the immunohistochemical stain of SP and EGF/EGFR was faint and without obvious change during the wound healing process. The tendency of the EGF mRNA/EGFR mRNA expression was similar to that of EGF/EGFR. CONCLUSIONS: During wound healing, SP may promote the healing process by affecting the expression of EGF/EGFR in the granulation tissues.
Animals↗
Relations of transcription expression of IL-2 with nuclear factor of activated T cells as well as changes of C-Fos and C-Jun after trauma.
OBJECTIVE: To observe the relations among expression of interleukin-2 (IL-2) in spleen lymphocytes, DNA binding activity of nuclear factor of activated T cells (NFAT) and expression of the partly family members C-Fos, C-Jun after trauma. METHODS: A murine closed trauma model was used, animals were sacrificed 6, 12 hours and 1, 4, 7, 10, 14 days, respectively after injury. Spleen lymphocytes were isolated from injured mice and stimulated with concanavalin-A. The culture supernatants were harvested and assayed for IL-2 activity. Total RNA was extracted from spleen lymphocytes and assayed for IL-2 mRNA. Nuclear protein was extracted, and the DNA binding activity of NFAT was measured using an electrophoretic mobility shift assay (EMSA), the expressions of C-Fos, C-Jun protein determined by Western blot analysis. RESULTS: The expressions of IL-2 activity and IL-2 mRNA in spleen lymphocytes were decreased in injured mice compared with those in control mice, and the most obvious decrease appeared on the 4th day after injury. The DNA binding activity of NFAT decreased gradually and reached the minimum that was only 41% of the control on the 4th day after injury, which was closely associated with the decline of IL-2 activity and IL-2 mRNA. An decrease in the expression of C-Fos on the 1st and 4th day after injury, trauma had no significant effect on the C-Jun expression. CONCLUSIONS: These results suggest that the inhibition of IL-2 expression is partly due to the impairment in the activation of NFAT in injured mice; and the decline in the DNA binding activity of NFAT is partly due to trauma block in the C-Fos expression.
Animals↗
Pathomorphological changes after liver impact injury in rabbits.
OBJECTIVE: To investigate the histopathological changes in the liver and other organs after impact injury. METHODS: The rabbits were impacted with a BIM-IV biological impacting machine at the xiphoid process. The severity of liver injury was graded and scored through gross anatomy. At the same time, the pathological changes in the liver, heart, and lung were observed by light and electron microscopes. RESULTS: Light microscopy showed that the pathological changes in the liver were: 1) loss of normal structure, hemorrhage and distortion of hepatic lobules; 2) cloudy swelling, degeneration, vacuolation and necrosis of liver cells; 3) infiltration of neutrophils. The lungs were injured and there were liver cell emboli in the small pulmonary arteries. Electron microscopy showed that the ultrastructure of the liver cells was severely damaged and the cells had significant features of necrosis. CONCLUSIONS: The major pathomorphological changes in the liver after impact injury are hemorrhage and necrosis. They may be complicated by exfoliation of liver cells to hepatic sinusoids. These cells circulate with the blood to form emboli in the pulmonary blood vessels.
Animals↗
Decline in the expression of IL-2 after trauma and changes in the nuclear transcription factors NFAT and AP-1.
OBJECTIVE: To investigate whether the decrease in expression of interleukin-2 (IL-2) after trauma is associated with changes in DNA binding activity of nuclear factor of activated T cells (NFAT) and activator protein-1 (AP-1). METHODS: Mice with closed impact injury with fracture in both hind limbs were adopted as the trauma model. Spleen lymphocytes were isolated from traumatized mice and stimulated with Con-A. Culture supernatants were assayed for IL-2 activity, and total RNA was extracted from spleen lymphocytes and assayed for IL-2 mRNA. DNA binding activity of NFAT and AP-1 were measured by electrophoretic mobility shift assay (EMSA). The expression of c-Fos, c-Jun and JunB proteins was determined by the Western blot analysis. RESULTS: DNA binding activity of NFAT and AP-1 gradually decreased to a minimum of 41% and 49%, respectively, of the control on the 4th day after injury, which was closely followed by the decline in IL-2 activity and IL-2 mRNA. A decrease in the expression of c-Fos on the 1st and 4th day after trauma had no significant effect on c-Jun expression; the increase in expression of JunB was only on the 1st day after injury. CONCLUSION: Decreased IL-2 expression is, at least in part, due to a decline in the activation of NFAT and AP-1 in traumatized mice. The decline in DNA binding activity of NFAT and AP-1 is partly due to a trauma-induced block in the expression of c-Fos.
Animals↗
Effect of endothelin and endothelin A receptors on regional cerebral blood flow after traumatic brain injury in rabbits.
OBJECTIVE: To investigate the effect of endothel in and endothelin A receptors (ETAR) on regional cerebral blood flow after traum atic brain injury (TBI). METHODS: The changes of endothelin-1 (ET-1) content with radi oimmunoassay, mRNA expression and the location of ETAR with in situ hybridizatio n, and the function and effect of antagonist BQ123 on regional cerebral blood fl ow (rCBF) through intracisternal application were dynamically observed on 130 ad ult rabbits after TBI. RESULTS: ET-1 increased significantly in regional brain tissue s, and the expression of ETAR mRNA increased apparently and predominantly distri buted in the cerebromicrovascular endothelium after trauma. The rCBF declined si gnificantly, but by using selective ETAR antagonist BQ123 to treat the rabbits, the decrease of rCBF could be apparently prevented. CONCLUSIONS: It demonstrates that ET-1 may primarily contribut e to the rCBF decrease after TBI, while providing that the role of ET-1 is medi ated through ETAR.
Journal Article↗