BACKGROUND: Brain injury can be induced by repeated high positive acceleration ( + Gz) exposure, but the mechanism was still unclear.OBJECTIVE: To investigate the role of apoptosis in higher + Gz exposures induced brain injury by observing the changes of mRNA expression of bcl-2,bax, p53, and interleukin-1β(IL-1β) hydroxylase in rat brain.DESIGN: Randomized control experimental study based on experimental SD rat model.SETTING: Aviation medicine research center of a hospital.MATERIALS: Twenty-six healthy male SD rats, weighed from 180 to 220 g,were randomly divided into control group(4 rats) and + Gz exposure group (22 rats).INTERVENTIONS: Rats were fixed on the rotating arm of animal centrifuger with their heads towards axis. Rats in + Gz exposure group were exposed to + 14 Gz for three times, each for 45 seconds with 30 minutes interval in between. Rats in control group were subject to the same experiment in + 1 Gz. The rat brains were taken 30 minutes, 6 hours, 24 hours and 48 hours after the last centrifuge run, and then fixed and embedded. Changes of bcl-2, bax, p53, and IL-1β hydroxylasein mRNA expressions in rat brain were measured with semi-quantitative reverse transcription polymerase chain reaction(RT-PCR) . Apoptotic cells were detected by terminal deoxynucleotide(correction of deoxynuleotide) transferase-mediated dUTP nick end labeling(TUNEL) technique.MAIN OUTCOME MEASURES: The changes of bcl-2, bax, p53, and IL-1 β hydroxyalse mRNA expressions at each time points.RESULTS: After repeated + Gz exposures for 6 hours, bcl-2 mRNA expression in rat brain tissue(0. 32 ± 0. 08) was found significantly lower than in control group(0. 69 ± 0. 15), while mRNA expressions of bax, p53, and interleukin-1β converting enzyme(ICE) 0.55 ±0. 09, 0. 48 ±0. 12, 0.79 ±0. 12were significantly higher than in control group 0.33 ±0. 09, 0. 31 ±0.05,0.51 ± 0.09 ( P ＜ 0. 01 ) . After 24 hours of exposure, mRNA expression of bcl-2 in rat brain tissue (0. 28 ± 0.05) was significantly lower than in control group, while the mRNA expressions of bax, p53, and ICE 0.61 ±0. 15,0.54 ± 0. 07, 0. 84 ± 0. 15 were significantly higher than in control group ( P ＜ 0.01); but the difference of brain bcl-2, bax, p53 and ICE mRNA expressions had no statistical significance when exposed for 0.5 hour and 48 hours( P ＞ 0.05). Partly apoptotic cells were observed at exposure for 6 hours and 24 hours.CONCLUSION: Changes of bcl-2, bax, p53 and ICE mRNA expressions, as well as apoptosis in rats brain can be induced by repeated + Gz exposures and may be involved in the molecular mechanisms of brain injury.

BACKGROUND:Standard artificial prosthesis does not well match to patients' skeleton due to absolute individuation,while the difference between them does not keep the stabilization of artificial joint for a long term.OBJECTIVE:To construct three-dimensional models of custom-made femoral prosthesis by using computer-aided design and to verify whether custom-made femoral prosthesis is superior to popular femoral prosthesis via simulating and contrasting mechanical study.DESIGN,TIME AND SETTING:Opening study was performed in the Orthopaedics Institute of the First Clinical Hospital and the Biomechanics Institute,Jilin University between September 2006 and May 2007.MATERIALS:One fresh femur was derived from adult corps.METHODS:Two-dimensional images of the fresh femur was obtained by using total-length CT scanning and processed with computer edge recognition and three-dimensional contour extraction software to identify outer and inner contour of bone cavity,extract contour data of bone cavity and prosthesis,and construct three-dimensional models of femur and custom-rhade femoral prosthesis.SolidWorks software was used to establish three-dimensional prosthetic models in common biological and bone cement types; moreover,bone-cement,biological,and custom-made femoral prosthesis were replaced via simulating clinical surgery.MAIN OUTCOME MEASURES:Standing on single or double feet was simulated to measure stress distribution,interface stress,and primary micromotion of femoral prosthesis in the three types.RESULTS:Edge extracting was replaced by Canny calculator,characterizing by stable running,credible outcome,and consistent with the primary request.Stress,femoral stress,interface stress,and primary micromotion of custom-made femoral prosthesis were significantly lower than biological and'bone-cement femoral prosthesis (P ＜ 0.01).CONCLUSION:The computer-aided design is reliable to perform the assistant design of prosthesis; furthermore,biomechanical properties of the custom-made femoral prosthesis are superior to those of popular femoral prosthesis.

The purpose of this study is to observe the changes in gene expressions of bcl 2, bax, p53 and interleukin 1? converting enzyme (ICE) in the cerebral tissue of rat exposed to repeated +Gz, and to explore the pathogenetic role of apoptosis in brain damage induced by repeated +Gz exposures. The expression levels of bcl 2, bax, p53 and ICE in cerebral tissue of rats exposed to repeated +Gz were measured by semi quantitative reverse transcription polymerase chain reaction (RT PCR), and the apoptotic cells in brain tissue were detected by terminal deoxynuleotidyl transferase mediated dUTP nick end labeling technique. The results showed that the bcl 2 expression levels in the brain 6h and 24h after repeated +Gz exposures were significantly lower than those of control group, whereas the bax, p53 and ICE expression levels in the brains tissue 6h and 24h after repeated +Gz exposures were significantly higher than those of control group. Apoptotic cells could be observed in cerebral cortex, CA1 subregion of hippocampus and striatum at 6h and 24h after repeated +Gz exposures. It is suggested that the changes in bcl 2, bax, p53 and ICE expressions in rat brain can be induced by repeated +Gz exposures and apoptosis might be one of the molecular mechanisms of brain damage induced by repeated +Gz exposures

Objective To investigate the influences on the femur cortex of the rabbit after ovariectomy and its mechanism.Methods Eighty 6 months-old female pure New Zealand rabbits were divided into two groups:40 rabbits in ovariectomy group and 40 in sham-operation group.The weight averaged 2.2±0.28 kg.Four weeks and 8 weeks after operation,a series of tests were performed in both groups concerning the number,the volume,the rate and the maximal load of cortical bone porosity.The number,the length and the density of linear crack in rabbit femur cortex were documented after repetitive application of minor trauma.Results Micro-CT demonstrated that both on week 4 and 8 after operation,the number,the volume and the rate of cortical bone porosity were all significantly higher in ovariectomy group than that of the control group.Four weeks after operation,the biomechanical test showed the significantly lower average maximal load of rabbit femur in ovariectomy group (1 892.60±59.09) than that of in control group (1 949.25±53.12) (P=0.003).Eight weeks after operation,the average load of both groups decreased to some extent,which was 1 944.55±41.76 in control group and 1 692.40±85.08 in ovariectomy group respectively (P=0.000).However,the average maximal load of ovariectomy group decreased more significantly.Having application of repetitive minor trauma to the bone,the number,the length and the density of linear crack of cortical bone were 3.40± 1.67,216.80± 17.60 μm and 0.40±0.08/mm2 in ovariectomy group,and 2.00± 1.17,160.45± 16.89 μm and 0.29±0.13/mm2 in control group 4 weeks later.And after 8 weeks,they were 5.15±1.18,334.60±13.94 μm and 0.35±0.10/mm2 in ovariectomy group,and 3.10±1.37,182.10±9.80 μm and 0.24±0.09/mm2 in control group.The number,the length and the density of linear crack of cortical bone were all significantly higher in ovariectomy group than that of in control group both on week 4 and on week 8 after operation.Conclusion Ovariectomy increases the porosity of cortical bone of rabbit,destroys its biological property,accelerates the fatigued damage and delays the healing process.These changes may be attributed to fracture and delayed union after fracture.

OBJECTIVE: To investigate the epidemiological characteristics, phenotype, genotype, and prognosis of medium-chain acyl-CoA dehydrogenase deficiency (MCADD) in the Chinese population. METHODS: A retrospective analysis was performed for the clinical data of the neonates who underwent screening with high-performance liquid chromatography-tandem mass spectrometry from January 2009 to June 2018 and were diagnosed with MCADD by gene detection. RESULTS: A total of 2 674 835 neonates underwent neonatal screening, among whom 12 were diagnosed with MCADD. Gene detection was performed for 10 neonates with MCADD and found 13 mutation types at 16 mutation sites of the ACADM gene, among which there were 7 reported mutations (p.T150Rfs*4, p.M1V, p.R206C, p.R294T, p.G310R, p.M328V, and p.G362E), 5 novel mutations (p.N194D, p.A324P, p.N366S, c.118+3A>G, and c.387+1del G), and 1 exon 11 deletion; p.T150Rfs*4 was the most common mutation (4/16). The detection rate of mutation sites in the ACADM gene was 80%. No phenotype-genotype correlation was observed. Dietary guidance and symptomatic treatment were given after confirmed diagnosis. No acute metabolic imbalance was observed within 4-82 months of follow-up. All neonates had good prognosis except one who had brain dysplasia. CONCLUSIONS MCADD is relatively rare in southern China, and p.T150Rfs*4 is a common mutation in the Chinese population. Cases with positive screening results should be evaluated by octanoylcarnitine C8 value and gene detection.
Acyl-CoA Dehydrogenase ; deficiency ; Carnitine ; China ; Follow-Up Studies ; Humans ; Infant, Newborn ; Lipid Metabolism, Inborn Errors ; Mutation ; Neonatal Screening ; Retrospective Studies

OBJECTIVE: To explore the clinical features and variations of ACADVL gene in 9 neonates with very long chain acyl-coenzyme A dehydrogenase deficiency (VLCADD). METHODS: VLCADD was suspected based on the results of neonatal screening by tandem mass spectrometry (MS-MS), with tetradecenoylcarnitine ± tetradecenoylcarnitine/octanoylcarnitine (C14: 1 ± C14: 1/C8) as the mark indexes. Infants with positive outcome were confirmed by sequencing of the ACADVL gene. RESULTS: Among 9 VLCADD cases, one case lost during follow-up, the observed phenotypes comprised 2 with severe early-onset form, 1 with hepatic form and 5 with late-onset form. Optimal outcome was acquired for all patients except the 2 early-onset cases. In total 16 ACADVL variations were detected among the 9 infants, which included 8 novel variations (c.96-105del GCCCGGCCCT, c.541C>T, c.863T>G, c.878+1G>C, c.895A>G, c.1238T>C, c.1276G>A, and c.1505T>A) and 11 missense variations. There were 9 genotypic combinations, including 1 homozygote and 8 compound heterozygotes. Except for two patients carrying null variations, all had a good outcome. CONCLUSION VLCADD is relatively rare in southern China, for which late-onset form is common. Carriers of null variations of the ACADVL gene may have relatively poorer clinical outcome. Above results will provide valuable information for the diagnosis and management of VLCADD.
Acyl-CoA Dehydrogenase, Long-Chain ; deficiency ; genetics ; Carnitine ; China ; Humans ; Infant, Newborn ; Lipid Metabolism, Inborn Errors ; genetics ; Mitochondrial Diseases ; genetics ; Muscular Diseases ; genetics ; Neonatal Screening

Objective To explore the effect of EZH2 on Hcy-induced cholesterol accumulation of foam cells. Methods THP-1 foam cells were divided into control group ,100 μmol/L Hcy group and folic acid group. Lipid droplet in foam cells was tested by Oil red O. TC and TG contents in cells were determined by enzymic meth od. H3K27me3 level and EZH2 protein expression were detected by Western-blot. EZH2 mRNA expression was assayed by q-PCR. H3K27me3 level and TC and TG contents were examined followed by overexpression or knock- down of EZH2. Results After administration of Hcy,TC and TG contents in foam cells were increased (P <0.05). H3K27me3 level and EZH2 expression were also increased(P<0.05). Overexpression of EZH2 caused the expansion of H3K27me3 level,and the TC and TC contents were also increased(P<0.05). Conclusion Regula-tion of H3K27me3 by EZH2 might be involved in Hcy-induced accumulation of cholesterol in foam cells.