As the largest microbial community in the human body,the intestinal microecology plays a pivotal role in the health and disease progression of the host.As part of the human symbiotic system,the metabolites of the intestinal microecology have a profound impact on the physiological and pathological states of the host.Hospi-tal-acquired infections(HAIs),as a common health problem among hospitalized patients,involve complex necha-nisms influenced by multiple factors.In recent years,with the advancement of technologies such as 16S rRNA and shotgun sequencing,researchers have gradually recognized that the intestinal microecology plays an important role in the occurrence and development of HAIs.In the intensive care unit,the treatment of primary diseases,sec-ondary infections,and the use of clinical treatment methods often lead to intestinal microecological imbalance.This article reviews the characteristics of changes in the intestinal microecology of critically ill patients after admission and explores the relationship between these changes and HAIs,aiming to deeply explore the possible mechanisms of the intestinal microorganisms in affecting the hospital-associated infections and provide theoretical support for developing prevention and treatment strategies.

As the largest microbial community in the human body,the intestinal microecology plays a pivotal role in the health and disease progression of the host.As part of the human symbiotic system,the metabolites of the intestinal microecology have a profound impact on the physiological and pathological states of the host.Hospi-tal-acquired infections(HAIs),as a common health problem among hospitalized patients,involve complex necha-nisms influenced by multiple factors.In recent years,with the advancement of technologies such as 16S rRNA and shotgun sequencing,researchers have gradually recognized that the intestinal microecology plays an important role in the occurrence and development of HAIs.In the intensive care unit,the treatment of primary diseases,sec-ondary infections,and the use of clinical treatment methods often lead to intestinal microecological imbalance.This article reviews the characteristics of changes in the intestinal microecology of critically ill patients after admission and explores the relationship between these changes and HAIs,aiming to deeply explore the possible mechanisms of the intestinal microorganisms in affecting the hospital-associated infections and provide theoretical support for developing prevention and treatment strategies.

Objective To study the surgical indications and effectiveness of short segment pedicle screw fixation plus pecutaneous vertebroplasty (PVP) for single thoracolumbar fracture combined with Kümmell disease.Methods Between June 2012 and June 2014,a prospective case series analysis was made on the clinical data of 15 selected cases of single thoracolumbar fracture patients who were combined with Kümmell disease.There were three males and 12 females,with an average age of 62.5 years (range,48-80 years).The iujured vertebrae were located at T11 in 3 cases,at T12in 4,at L1 in 5 and at L2 in 3.All the patients were treated by short segment fixation plus PVP.Operative time,surgery-related complications and adjacent vertebral fracture during follow-up were recorded.The effectiveness of the treatment was appraised by visual analogue scale (VAS),Oswestry Disability Index (ODI),Cobb angle of operative segment,which were recorded preoperatively,one week post-operatively and at final follow-up.One-way ANOVA (Analysis of Variance) was employed for statistical analysis.Results The operative time was 0.8-2 hours (mean,1.35 hour).There was no observation of incision infection,nerve injury,cement leakage or other related operative complications.A total of 15 patients were followed up for 16-36 months (mean,22.4 months),which showed solid fusion and bone bridges in all patients,with no fracture of adjacent vertebra observed.VAS was improved from preoperative (5.93 ± 0.62) points to (1.80±0.64) points one week postoperatively and (2.60 ± 0.53) points at final follow-up.ODI was improved from preoperative 61.53 ± 4.30 to 19.93 ±3.26 one week postoperatively and 23.07 ± 4.06 at final follow-up.Cobb angle of operative segment was improved from preoperative (17.40 ± 6.73) ° to (9.53 ± 3.12) o one week postoperatively and (11.00 ± 3.20) ° at final follow-up.There was significant difference of all the indexes namely,VAS,ODI and Cobb angle,between preoperative and one week postoperative status as well as between preoperative and final follow-up (P ＜ 0.05 or 0.01).However,there was no significant difference between ODI and Cobb angle in one week postoperatively and at last follow-up (P ＞ 0.05).Conclusion For single thoracolumbar fracture with Kümmell disease,short segment fixation plus PVP can shorten the surgery time,reduce the rate of complications,relieve pain,recover the function and avoid loss of kyphosis correction,as is worthy of clinical recommendation.

Objective To observe the ultrastructure of the neurovascular Unit (NVU) in chronic compressive cervical myelopathy rat model at different stages.Methods From March, 2014 to March, 2015, 32 rats were divided into two groups: sham control group (n =8) and compressive spinal cord injury group (n =24).The model was established by inserting the compression sheet made of polyurethane at the level of C6.BBB and somatosensory evoked potentials (SEP) were used to evaluate the spinal cord function status of model rat.Transmission Electron Microscopy (TEM) examination of compressive cervical spinal cords was performed separately at the 14th, 21st, 28th and 42nd day after modeling.Results At the 14th, 21st, 28th and 42nd, the BBB score were 17.571 ± 0.870, 15.952 ± 0.870, 15.476 ± 0.602 and 16.190 ± 0.632 were significantly lower than those in the control group (the BBB score of 4 points were 19.600 ± 0.516, 19.500 ± 0.527, 19.600 ± 0.699 and 19.800 ± 0.6232 respectively) (P ＜ 0.05).Latency prolongation and amplitude reduction of somatosensory evoked potentials (SEP) were presented in the compressive spinal cord injury group.At the 14th day, edema around the capillaries was observed, the morphological structure of endothelial cells and basement membrane was normal, the tight junction between endothelial cell was intact, the mitochondria in the axons, oligodendrocytes and astrocyte foot processes were edematous.At the 21st day, extensive edema, even partial necrosis around the capillaries were found, the surrounding structure were arranged loosely, partial loss of endothelial cells and basement membrane, cavitation occurrence in endothelial cells, basal membrane density was significantly lower, mitochondria vacuoles and shrinkage in the cytoplasm, axon myelin loose or broken;at the 28th day, the edematous range surrounding capillaries narrowed, low density of basement membrane and endothelial cells, vacuoles in endothelial cells, loose axon myelin, while some mitochondrias backed to normal.At the 42nd day, capillary integrity, no abnormalities were found in endothelial cells, basement membrane, tight junction and mitochondria, double layers of endothelial cells and basement membrane could be seen, local broken and loose structure were presented in part of the axons;The TEM of the sham control group showed normal ultrastructure of NVU.Conclusion The ultrastructure of NVU in chronic cervical spinal cord compression presented various in the different periods, NVU disruption were found in the early stages (14th-28th days), and compensatory and repair process were developed incompletely later.

After the medical informatics undergraduate course system recommended by GMDS was analyzed and summarized, the 5 principles for constructing medical informatics undergraduate course system were put forward ac-cording to the medical informatics undergraduate course system in China at present.The plan of offered new courses was proposed on the basis of medical informatics course system in our university in order to train the society-needed complex medical informatics professionals and achieve the long-term healthy development of medical informatics.

As an independent discipline medical informatics has been years of rapid development, and has made many important achievements. The future key development and direction of medical informatics were studied and predicted from the visual angle of information chain with certain measures put forward for the solution of problems in the development of medical informatics.

As an emerging cross subject in the information era, medical informatics has come into being due to the wide application of modern information science and computer technologies in medical sciences.Although great suc-cesses have been achieved in its education and research both in China and foreign countries, there are a number of problems that need to be solved in its new development environment.In this paper, the education of medical infor-matics in China in the past 10 years was reviewed and its achievements in Central South University were summarized with suggestions put forward for its future development.

Objective To establish a novel chronic compressive cervical spinal cord injury rat model,to validate the chronic pathological characteristic.Methods Fifty-four SD rats were randomly divided into 3 groups,including control group(n =6),acute compressive group(4 h,24 h,respectively.n =6),and chronic compressive group(4 h,12 h,24 h,48 h,72 h and 1week,respectively.n =6).Two sizes of water-absorbing polyurethane polymer sheets were implanted into C5～6 epidural space on postero-lateral side in acute and chronic compressive group respectively,to induce a consistent compression in the cord after expanded.While a laminectomy on C5～6 was performed only in control group.The neurological integrity,MRI signal change in the cords,large motoneuron number in the ventral horn,and myelin staining intensity on posterior funiculus were studied.Results In the acute group at 4-24 h,the compression was confirmed significantly on T2WI image,as well as hypointense signal change intramedullary.These changes were consisted with intramedullary bleeding,tissue necrosis.Large motoneuron number(P ＜ 0.05),rather than myelin staining intensity (P ＞ 0.05),was significantly decreased compared with the control group and chronic compressive group.BBB score was 6.0 at 24 h.In the chronic group:cord distortion with progressive compression was observed on T2WI image,but without intramedullary bleeding signal change.At 4-12 h,intramedullary edema,central canal distortion were seen in the cords.Large motoneuron number and myelin staining intensity decrement were not significant(P ＞0.05).BBB score was 20.6.At 24-72 h,central canal enlargement,venous congestion,and edema were observed.Large motoneuron number was less than that in the control group.In the compressive epicenter,nerve fiber disorganization or rupture was observed.Myelin staining intensity decreased significantly after 48 h and 72 h compression (P ＜0.05).BBB score was 19.3.At lweek,vacuolation changes were noted and large motoneuron decreased (P ＜ O.05),as well as myelin density and staining intensity (P ＜ 0.05),suggesting nerve fiber demyelination.BBB score was 17.5.In the control group,there was no neurological deficit and pathological change in the cords.Conclusion The pathology and MRI characteristic consistent with chronic compressive injury change,which proved this method is able to induce a chronic course on the rat model,and established a reliable model foundation for cervical myelopathy.

Objective To investigate the feasibility of mono-segment pedicle instrumentation (MSPI)in management of thoracolumbar fracture (AO classification,A1 and A3) by being compared with short-segment(two-segment) pedicle instrumentation(SSPI).Methods Overall 141 patients with tape A1 or A3 thoracolumbar fractures,aged from 20 to 60 years (average,40.5 years),were enrolled in this prospective study.According to a simple randomized method,35 patients with type A1 fracture and 41 patients with type A3fracture were treated with MSPI,while 26 with type A1 fracture and 39 with type A3 fracture were treated with SSPI.Low back outcome score (LBOS) and ASIA2000 were used to evaluate clinical outcome.Eighteenth month postoperatively was assigned as the last follow up period.Wedge index (WI) and sagittal index (SI) of the affected vertebrae on radiography were measured and compared preoperatively,one week postoperatively and at the final follow-up.Results All patients were followed up successfully.The blood loss and duration of operation of MSPI group were significantly less than that of SSPI group,respectively.However,there were no significant differences of clinical outcome between two groups.For type A1 fracture,correction rate and correction loss of WI in MSPI group were better than those in SSPI group.For type A3 fracture,there were no significant differences of correction rate and correction loss of WI and SI between MSPI group and SSPI group; however,the failure rate of MSPI group was significantly higher than that of SSPI group.Conclusion For type A1 and partial type A3 thoracolumbar fractures,MSPI can provide the same or better fixation with less blood loss and operative duration than SSPI.Since MSPI for type A3.2 thoracolumbar fracture has a higher failure rate,the surgical indication should be strictly controlled.

ObjectiveThe aim in this study was to evaluate the efficacy of the ball tip probe technique in placing pedicle screws in patients.MethodsFrom May 2009 to June 2010,we used ball tip probe technique in pedicle screw placement in patients with scoliosis,spondylolisthesis,spinal fractures and other diseases.The ball tip probe consisted of a metal shaft with a metal ball-shaped tip whose size included 1.5,2.5,3.0,3.5 mm in diameter.The ball tip probe with a diameter of 1.5mm owned a high rigidity and certain flexibility.Ball tip probe technique:A high speed bur was used to remove cortical bone and create a starting point,and then the ball tip probes is tapped gently by a hammer for making a guide hole through the pedicle into the vertebral body.The accuracy of the pedicle screw placements was evaluated on postoperative axial CT scanning The pedicle screw placements was compared between the the ball tip probe group and conventional freehand technique group.ResultsThree hundred and twelve screws were evaluated in the ball tip group and 276 in the conventional freehand group.All the screws (100％) were in the desired pedicle in the ball tip group and 215 (78％) in the conventional group.In the conventional group,23 screws(8.3％) were classified as medial violation; 38(13.7％) as lateral violation.A significant difference was determined between the 2 groups regarding the pedicle breaches.No vascular,pulmonary,or neurological injuries caused by pedicle screws placement was found in either group.ConclusionThis study demonstrates the accuracy and reliability of the ball tip probe technique in pedicle screw placement.This technique can probably reduce the risk of complications of screw misplacements.