BACKGROUND:When the intervertebral disc is under stress, the hydraulic pressure generated inside the nucleus pulposus makes the annulus fibrosus extend outward and expand, and the annulus colagen fibers are stretched so that the extracelular matrix of annulus fibrosus cels is also under the pressure. In the intervertebral disc, aggrecan is the main component of proteoglycans, matrix metaloproteinase-2 is a major enzyme for extracelular matrix degradation, and tissue inhibitor of metaloproteinase is a multifunctional specific inhibition factor for matrix metaloproteinase activity. There is a mutual regulation between the latter two to keep the homeostasis between them.
OBJECTIVE: To investigate the mechanism of cyclic tensile strain in the metabolism of intervertebral disc annulus matrix.
METHODS:Rat anulus fibrosus cels were subjected to 2% or 10% cyclic tensile strain at 1.0 Hz for 2 and 12 hours using Flexcel4000 tension system. Then cels were colected and cultured in conditioned medium for gene and protein detection. Real-time quantitative PCR was used to detect mRNA expression of aggrecan, matrix metaloproteinases-2 and tissue inhibitor of metaloproteinase-2. Gelatin zymography was used to detect matrix metaloproteinases-2 activity.
RESULTS AND CONCLUSION:The use of 2% cyclic tensile strain had no obvious effect on the stress fiber of actin cytoskeleton, whereas actin cytoskeleton was depolymerized in response to 10% cyclic tensile strain. The 2% cyclic tensile strain raised the expression of Aggrecan at 12 hours; whereas raised the matrix metaloproteinases-2 and tissue inhibitor of metaloproteinase-2 at 2 hours, both of which were in homeostasis; matrix metaloproteinases-2 activity had no significant changes. 10% cyclic tensile strain had no effect on the mRNA expression of Aggrecan. No matter stretching 2 or 12 hours, the matrix metaloproteinases-2 was up-regulated, and the tissue inhibitor of metaloproteinase-2 was down-regulated, both of which were not in balance. Moreover, the matrix metaloproteinases-2 activity was not significantly changed. These findings indicate that the mRNA expressions of Aggrecan, matrix metaloproteinases-2 and tissue inhibitor of metaloproteinase-2 alter in response to cyclic tensile strain in rat anulus fibrosus cels, and the tensile strain induces different mechano-responses in the actin cytoskeleton.

Objective To investigate the clinical status of post-core crown in anterior teeth aesthetical restoration and to observe its effect. Methods 126 cases of anterior teeth in patients with mild deformity,restored with post-core crown after informed consent meanwhile conducted clinical follow-up observation. Results In addition to 2 cases of disease after root canal treatment, 1 incisal and labial surface of porcelain fracture, other cases achieved desired results in the way of self-satisfaction,clinical efficacy and x-ray observation and periapical films. Conclusion Post-core crown in anterior aesthetical restoration has a unique position and clinical efficacy.

Objective To analyze the operation of long-term effect of edge to edge mitral repair for mitral vavle moderateto-severe insufficiency in children retrospectively.Methods Clinical dates of 102 patients who underwent edge to edge mitrel valve repair in Nanjing Children's Hospital from March 2003 to March 2015 were collected.Postoperative thoracic echocardiography was adopted to observe the effect of mitral valve forming and evaluate the follow-up results.Results The whole group of 2 patients died in hospital,Followed up for 1 months to 12 years,during the follow-up of 10 patients were lost.The early fol low-up,medium-term follow-up and long-term follow-up were completed 93,55 and 26 cases,respectively.In the early followup,6 patients had recurrent moderate mitral regurgitation(MR),and 5 patients had recurrent moderate-to-severe MR and reoperated during the follow-up period,a total of 2 cases died.In the medium-term follow up,moderate and severe MR were found in 6 and 4 cases,respectively.Three patients accepted reoperation,two patients died.In the long-term follow-up,1 case had recurrent severe MR,2 cases had re-operation and had no death.Early survival rate was 97.8 ％ (91/93),avoid reoperation rate was 94.6％ (88/93).The incidence of moderate or severe mitral regurgitation was 11.8％ (11/93).Midtcrm survival rate was 96.4％ (53/55),avoid reoperation rate was 94.6％ (52/55),moderate or severe mitral regurgitation rate was 18.2％ (10/55).Long-term follow-up have no death,avoid reoperation rate was 92.3 ％ (24/26),mitral valve moderate and above reflux rate was 7.7 ％ (2/26).The actuarial survival and freedom from MV reoperation rate was (92.4 ± 2.4) ％ and (77.7 ± 6.4) ％ at 10 years,respectively.Conclusion Edge to edge mitral repair in the treatment of children with moderate to severe mitral insufficiency had relatively stable curative effect,relatively fewer complications,and high long-term clinical effect.

Many studies have shown that abnormal expression and modification of lamin are closely related to aging.Hutchinson-Gilford progeria syndrome(HGPS)is a rare and severe premature aging disease caused by mutations in the gene encoding nuclear envelope proteins of A-type lamins (LMNA).The pathogenesis of HGPS is similar to the aging process of normal individuals,thus research on HGPS will be helpful for understanding the mechanisms of senescence and developing antiaging drugs.This paper reviews recent advances in lamin and the pathogenesis and treatment of HGPS,in order to provide a reference for further basic and clinical research on HGPS.

Objective: To explore the role of tentorium cerebelli hiatusincision in treating severe and most severe brain injuries complicated by tentorial herniation.Methods: From July 1994 to July 1999 tentorium cerebelli hiatus incision was done based on intracranial hematoma evacuation and bone flap craniectomy decompression in 70 cases of severe and most severe brain injuries complicated by tentorial herniation.Results: Of the 70 cases, GCS 3-5 was in 23 and GCS 6-8 in 47; satisfactory recovery in 39 cases (55.7%), moderate disability in 12 (17.1%), severe deficit in 6 (8.6%), vegetative survival in 4 (5.7%) and 8 (11.4%) died.Conclusions: Tentoriun cerebelli incision is helpful in alleviating secondary brain stem injury from tentorial herniation and in reducing the disability and death rate of the patients.

Objective:To understand clinical effect of a homemade infants wrist hand thumb joint fixtures to prevent the unplanned extubation (UEX) in radial arterial puncture tube in children with congenital heart disease.Methods:From October 2016 to October 2019, 150 cases infants patients with simple congenital heart disease in cardiac surgery of the First Affiliated Hospital of University of Science and Technology of China were selected as the research objects, and the radial artery invasive manometric tube was routinely indwelling after operation. Subjects were randomly divided into observation group and control group, with 75 cases in each group. In the observation group, the wrist joint of children was fixed with homemade fixation device. The control group used conventional fixation methods to fix the wrist joint of infants. The incidence of pressure injury and unplanned extubation were compared between the two groups.Results:There was 1 case (1.33%) pressure injury in the observation group and 2 cases (2.67%) in the control group, and there was no statistical significance in the two groups ( P>0.05). The unplanned extubation rate of radial artery pressure tube occurred in 5 cases (6.67%) in the observation group, and lower than that in the control group (17/75, 22.67%) ( χ2=7.67, P<0.01). When children in the state of agitation and very agitation, the incidence of unplanned extubation rate in the observation group was 0 and 4.35%(1/23), lower than that in the control group 15.79%(6/38) and 35.00% (7/20), respectively ( χ2=6.19, 6.64, both P<0.05). With the extension of ICU time, the incidence of unplanned extubation rate was increased. The incidence of unplanned extubation rate was 4.76% (2/42) and 9.09% (3/33) in the observation group and 18.18%(8/44) and 29.03% (9/31) in the control group when ICU time was ≤24 h and>24 h, respectively. The difference was statistically significant ( χ2=5.51, 4.17, both P<0.05). Conclusions:The homemade wrist thumb joint fixtures device for infants does not increase the pressure injury of the fixed part, and can reduce the incidence of unplanned extubation of radial artery manometric tube in children with congenital heart disease.