Pediatric acute respiratory distress syndrome (PARDS) is one of the most severe disease in pediatric critical care medicine with high mortality.Pediatric practitioners have recognized that ARDS in children is different from ARDS in adults.In the absence of identification of these differences,however,children have been characterized as having ARDS based on the adult definitions.Therefore,the managements for PARDS were conducted without specific considerations of children,and have limitations when applied to patients.With the purpose to highlight the gaps of ARDS between children and adults,the new insights into PARDS on the epidemiology,pathophysiology,diagnosis,treatment and prognosis in the recent years were summarized.

Objective To discuss the prevention and treatment of hemorrhage during or after minimally invasive percutaneous nephrolithotomy (PCNL). Methods Clinical data of 12 cases of hemorrhage during or after minimally invasive percutaneous nephrolithotomy from July 2005 to October 2005 in this hospital were retrospectively analyzed. Results Intraoperative hemorrhage occurred in 10 cases. The bleeding was stopped by pressure in 6 cases and a re-operation of open nephrolithotomy 5 days later was required in 4 cases. Postoperative hemorrhage was seen in 2 cases. The bleeding was successfully stopped by endoscopic electrocoagulation in 1 case and by interventional highly-selected embolization on the 4th day after operation in 1 case. Conclusions Prevention should be put first for hemorrhage during or after minimally invasive percutaneous nephrolithotomy. Accurate puncture and skillful tunnel expansion are the key to minimize the hemorrhage. Interventional embolization should be the first choice in case of massive or repeated bleeding.

Objective To construct eukaryotic expression plasmid pIRESneo3-pigment epithelium-derived factor (PEDF) and detect its transient expression in SP2/0 cells. Methods Specific primers were designed based on the mature peptide sequence of human PEDF cDNA in the GenBank. Human PEDF gene was cloned into the eukaryotic expression vector pIRESneo3. The PEDF DNA was transfected into SP2/0 with LipofectamineTM 2000. The recombinant human PEDF protein expressed in SP2/0 cell culture supernatant was identified by Western blot and enzyme-linked immunosorbent assay. The biological activity of the recombinant human PEDF was measured by 3-(4,5-dimethylthiazol-z-y1)-2,5-diphenytetrazolium bromide(MTT) method. Results PCR amplification, restriction enzyme digestion and DNA sequencing confirmed that the mature peptide sequence of human PEDF cDNA was successfully cloned into the eukaryotic expression vector pIRESneo3. And the plasmid was transfected into SP2/0 cells, which could secret PEDF. Western blot analysis showed that there was only one obvious band at the position of relative molecular weight of 50 000, and it is equivalent to the expected value. Enzyme-linked immunosorbent assay suggested that the content of PEDF began to rise after transfection, and peaked at 36 h [(0.92±0.04) μg/ml]. The proliferation of human umbilical vein endothelial cell line was significantly inhibited by supernatant after transfection of 36 h (P<0.05). Conclusions The eukaryotic expression plasmid pIRESneo3-PEDF had been successfully constructed and active human PEDF was transiently secreted, which made a foundation for further study of stable expression and purification of PEDF. This protein could be a potential medication for preventing and managing retinopathy of prematurity.

Objective To evaluate the role of haeme oxygenase-1 (HO-1) in remote limb ischemic preconditioning (RLIP)-induced attenuation of lung ischemia-reperfusion (I/R) injury in rabbits.Methods Twenty-four Japanese White Rabbits,aged 4-5 months,weighing 2.0-2.5 kg,were randomly divided into 4 groups (n =6 each) using a random number table:sham operation group (S group),I/R group,RLIP group and zinc protoporphyrin (ZnPP,an inhibitor of HO-1) plus RLIP group (ZnPP + RLIP group).Lung I/R was produced by 60 min occlusion of the left lung hilum followed by 180 min of reperfusion in I/R,RLIP and ZnPP + RLIP groups.RLIP and ZnPP + RLIP groups received 3 cycles of 10 min ischemia followed by 10 min reperfusion in the bilateral hind limbs immediately before occlusion of the left lung hilum.In ZnPP + RLIP group,ZnPP 10 μmol/kg was injected intravenously 10 min prior to hind limb ischemia and the rest of the procedures were similar to those previously described in RLIP group.At the end of reperfusion,arterial blood samples were collected for blood gas analysis.The animals were then sacrificed and pulmonary specimens were obtained for microscopic examination of the pathological changes which were scored (lung injury score,LIS) and for determination of wet/dry lung weight ratio (W/D ratio),myleoperoxidase (MPO) activity,malondialdehyde (MDA) content and expression and activity of HO-1 in the lung tissues.Results Compared with group S,PaO2 was significantly decreased,and LIS,W/D ratio,MPO activity,MDA content,and HO-1 expression and activity were increased in I/R group (P ＜ 0.01).Compared with I/R group,PaO2 and HO-1 expression and activity were significantly increased,and LIS,W/D ratio,MPO activity and MDA content were decreased in RLIP group (P ＜ 0.01).Compared with RLIP group,PaO2 and HO-1 expression and activity were significantly decreased,and LIS,W/D ratio,MPO activity and MDA content were increased in ZnPP + RLIP group (P ＜ 0.01).Conclusion RLIP up-regulates HO-1 expression and enhances HO-1 activity,thus reducing lung I/R injury in rabbits.

BACKGROUND:Many studies have confirmed that recombinant human bone morphogenetic protein 2 plays a very important role in bone formation and fracture healing, but recombinant human bone morphogenetic protein 2 alone implanted is prone to diffusion and degradation, which is unable to play a persistent role in new bone formation. OBJECTIVE:To explore the effect of recombinant human bone morphogenetic protein 2 composite bone in the rabbit lumbar fusion. METHODS:Thirty New Zealand white rabbits were selected to make posterior lumbar intertransverse fusion models, and then were randomly divided into three groups, in which, L5-6 intertransverse implantation of autologous iliac bone, al ogeneic bone and recombinant human bone morphogenetic protein 2 composite bone (recombinant human bone morphogenetic protein 2 and al ogeneic bone complex) was done respectively. At 6 weeks after implantation, gross observation, X-ray examination and histological observation were performed. RESULTS AND CONCLUSION:Fusion rate and percentage of new bone area were higher in the composite bone group than the autologous iliac bone and al ogeneic bone groups (P<0.05);the tensile strength was lower in the al ogeneic bone group than the other two groups (P<0.05), but there was no difference between these two groups except the al ogeneic bone group. X-ray films showed cal us formation in the implanted region of the three groups. In the autologous iliac bone group, a large amount of cartilage tissues formed along with a smal amount of bone trabeculae and a certain amount of woven bones. In the al ogeneic bone group, the implant was covered with a large amount of fibrous tissues, bone island was seen and there was also a smal amount of bone trabeculae and cartilage tissues. In the composite bone group, a great amount of bone trabeculae and cartilage tissues were visible to form woven bone and cortical bone. These findings indicate that the recombinant human bone morphogenetic protein 2 composite bone can obtain good effect in the rabbit lumbar fusion.

BACKGROUND:Posterior maleolar fracture is an important factor affecting the prognosis of ankle fractures. Posterior maleolar fracture often caused by high energy trauma. Using what kind of fixation and fixation materials biomechanics, and how to embed has become a current research hotspot. OBJECTIVE:To compare the clinical outcomes of different fixation materials on posterior maleolar fracture, and analyze the effect of different fixation methods on biomechanical outcome of posterior maleolar fracture fixation, so as to provide a basis and reference of selecting the best fixation for the clinical treatment of ankle fracture. METHODS: The relevant literature included by PubMed database and the China National Knowledge database from the year of 1976 to 2015 were retrieved by the first author through computer. English key words are “Ankle fracture; internal fixation; biomechanics; biocompatibility”, Chinese language search terms are “posterior maleolar fracture; internal fixation; biomechanics; biocompatibility”. Summarize the most commonly used metal fixation materials and absorbable content materials. The clinical commonly used metal fixation materials including bone plate and screws, absorbable fixation materials such as biodegradable material polylactic acid, polyethylene plastic ester, polylactide gum ester, etc. The biomechanical properties were analyzed. RESULTS AND CONCLUSION: The new locking screw can withstand more buckling and shear force. Lag screw has a tapping action, and the puling was stronger after tapping, but for patients with osteoporosis, the pressure effect of screw on fracture fragments was limited, the strength was not enough, at this time, locking plate should be used. Locking plate has a greater stability and higher confrontational feature to bending stress, less likely to pul out. Steel coupling screw provides better stability. To avoid secondary removing of the fixation, stress protection after fixation and other shortcomings after the metal material fixation fracture healing, the strength of the absorbable fixation material made by biodegradable material polylactic acid, polyvinyl acetate glue and polypropylene plastic ester after high temperature and pressure processing was increased. Absorbable fixation material may overcome the adverse effects associated with metal fixation, such as imageological examination, secondary implant removal. These results show that the mechanical properties of the absorbable screws are more closer to human bone, no surrounding bone vulnerability due to stress shields, no osteoporosis occurs, and can degrade in the body, but its fixation strength is stil less than the traditional fixed screw and bone plate. We should choose a suitable fixation material according to the forces of fracture site and the size of the fracture fragments.

BACKGROUND: Auto-neural transplantation is used widely on peripheral neurological defect, but it also has some difficulties. So some scholars try to use xenoma-neural transplantation; however, it is hard todeal with immunological rejection.OBJECTIVE: To study the effect of transforming growth factor-β1 (TGFβ1) used in local area on neural regeneration after transplantation of fresh nerve allograft.DESIGN: Randomized controlled study.SETTING: Hand Surgery Department of Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and TechnologY.MATERIALS: The experiment was conducted in the Union Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology between August 2001 and October 2002. Totally 60healthy adult Wistar rats from different confinements were randomly divided into three groups including experimental group, blank group and control group with 20 in each group.METHODS: TGF-β1 plasmid was prepared for using. Establishment of animal model: Sciatic nerve at the 0.5 cm deep of piriformis muscle of rats in the two groups was cut with disinfectant razor into chip regularly about 2.0 cm. The excisional nerve segment was exchanged to transplant plerosis neurological defect. TGF-31 was injected into the local muscles and bisection of nerve in the experimental group, and equal volume of saline was injected into rats in the blank group and the control group. In addition, rats in the experimental group and the blank group were not treated with any drugs, but cyclosporine A (15 mg/kg) was used to feed rats in the control group. Ten rats from each group were taken for section and staining at the 6th and the 12th week: ① Glees-luxot fast blue staining method; ② myelin sheath fast blue staining method. Axonal amount: Fields were randomly taken from the middle staining samples 12 weeks later and 1.0 mm2 interaxis-cylinder was counted under light microscope of 400 times. Comparisons among groups were analyzed with i test.MAIN OUTCOME MEASURES: Morphological observation and axonal amount of transplanted area in each group.RESULTS: Quantitative analysis of the experimental animals: Totally 60rats entered the final analysis without any loss. ① Infiltration of monocytes was observed widely in various areas of graft in the blank group;meanwhile, desiccation of myelin sheath and plenty of vacuolations were also observed, especially at the sixth week. The whole graft was infiltrated by monocyte with severe rejection. Few axis-cylinders were regenerated in the transplanted segment. At the 12th week, graft was slender, plenty of scar tissues were proliferated, edema was observed obviously, few Schwann cells and regenerated axis-cylinders were observed, and lots of regenerated axis-cylinders did not pass the whole graft. A few infiltrative monocytes were observed, and edema was observed obviously, but new vessel was formed in transplanted nerve, and regenerated axis-cylinders passed the whole graft in the experimental group and the control group.Lots of Schwann cells were observed at the 6th week; meanwhile, regenerated axis-cylinders passed the whole graft at the 12th week, a quantitative myelinization was formed, Schwann cells proliferated obviously, and edema between axis-cylinder was relieved. Numbers of peripherally regener ated axis-cylinder of nerve and remyelination in each ransplanted area were more than those in the central area, and edema between peripheral axis-cylinder was milder than that in the central area in the experimental group. ② Twelve weeks after operation, 5 rats in each group were selected to observe their fields, which were taken randomly from neural graft,under the microscope of 400 times to count 1.0 mm2 inter-axis-cylinders.Number of axis-cylinder was higher in the experimental group and the control group than that in the blank group, and the differences were significant [(78.3±4.6), (76.1±4.2) , (15.0±3.5) ,t=3.056, t=2.948, P ＜ 0.01];however, number in the experimental group was similar to that in the control group, and differences were not significant [(78.3±4.6), (76.1±4.2),t=1.982 P ＞ 0.05].CONCLUSION: TGF-β1 used in local area plays an immunosuppressive action locally, decreases host immunological rejection, increases the number of axis-cylinder, and accelerates growth of nerve.

To study the characteristics of acute rejection after limb allotransplantation, 29 male Sprague-Dawley rats were randomly divided into 2 groups, with 15 rats in control group and 14 rats in experimental group. Each rat in control group underwent limb replantation. Each rat in experimental group received limb transplantation from Wistar rat. No immunosuppressive drugs were used after operation. The circulation of the transplanted limb, time and signs of rejection, histopathological changes in the tissues of the limb graft when rejected and survival time of limb grafts were evaluated. In the control group, no signs of rejection were observed, the circulation of each replanted limb was normal, it could survive for a longer time. The experimental group showed clinical signs of rejection (sub dermal edema and erythema) after a mean time of 3.36+/-1.15 days, and the mean survival time of the allografts was only 7+/-0.78 days. Histopathological examination showed most violent rejection reaction in skin. It is concluded that with Wistar-to-SD limb transplantation without use of immunosuppression, rejection of the grafts would occur after a mean time of 3.36+/-1.15 days; the earliest signs of rejection were edema and erythema of the skin, skin being the most representative component of limb graft rejection.
Acute Disease ; Extremities/*transplantation ; *Graft Rejection ; Graft Survival ; Random Allocation ; Rats, Sprague-Dawley ; Rats, Wistar ; Skin/immunology ; Transplantation, Homologous

Protective effect of interleukin-1beta (IL-1beta) on motor neurons was studied after peripheral nerve injury. Twenty Wistar rats were divided into 2 groups randomly. The right sciatic nerve of each rat was resected. After silicon tubulization of sciatic nerve in rat, 15 microl 1 ng/ml IL-1beta and PBS solution were injected into the silicon capsule respectively. Enzyme histochemistry was performed to show acetyle cholesterase (AchE) and nitric oxide staining (NOS) activity of spinal alpha motor neurons in spinal segments 2 weeks later. Neurons were counted and the diameter and cross sectional (c/s) area of neurons were analyzed by using computer image analysis system. The results showed that as compared with the normal side, both enzyme activities significantly changed in motor neurons in PBS group. The diameter and c/s area of both neurons changed significantly too (P < 0.01). These results suggest that exogenous IL-1beta protects alpha-motor neurons from degeneration and necrosis after peripheral nerve injury.
Interleukin-1/*pharmacology ; Motor Neurons/*pathology ; Neuroprotective Agents/*pharmacology ; Random Allocation ; Rats, Wistar ; Sciatic Nerve/*injuries ; Spinal Cord/pathology

In order to investigate the biological function of transforming growth factor-β1 (TGF-β1) during fibrosis in denervated skeletal muscle, we recruited sciatic nerve injury model of SD rats in which denervated gastrocnemius was isolated for analysis. At different time points after operation, denervated muscle was examined by several methods. Masson trichrome staining showed morphological changes of denervated skeletal muscle. Quantitative RT-PCR detected the rapid increase of TGF-β1 expression at mRNA level after nerve injury. It was found that a peak of TGF-β1 mRNA expression appeared one week post-operation. The expression of collagen I (COL I) mRNA was up-regulated in the nerve injury model as well, and reached highest level two weeks post-injury. Immunoblot revealed similar expression pattern of TGF-β1 and COL I in denervated muscles at protein level. In addition, we found that the area of the gastrocnemius muscle fiber was decreased gradually along with increased interstitital fibrosis. Interestingly, this pathological change could be prevented, at least partly, by local injection of TGF-β1 antibodies, which could be contributed to the reduced production of COL I by inhibiting function of TGF-β1. Taken together, in this study, we demonstrated that the expression of TGF-β1 was increased significantly in denervated skeletal muscle, which might play a crucial role during muscle fibrosis after nerve transection.