Biomimetic restoration and regeneration of dentin and cementum / 口腔疾病防治

@#Dental hard tissues lack the ability to self-heal. In dentin and cementum, hydroxyapatite (HA) can exist outside and/or inside collagen fibers. It is difficult to repair or regenerate HA with a highly ordered orientation in the presence of collagen fibers. At present, the biomimetic mineralization of dentin and cementum, mainly carried out by imitating its biological formation process and its physiological structure, can be divided into those originating from the fiber mineralization mechanism and those with HA as the main component. The materials used include natural materials such as demineralized dentin matrix (DDM) and calcined bovine hydroxyapatite (BHA), and synthetic materials such as polymer-induced liquid precursor (PILP) and synthetic HA. In the future, natural materials and synthetic materials should be combined for the restoration and regeneration of dentin and cementum by means of biomimetic mineralization of calcium phosphate released by remineralization solution-HA.

Clinical results after surgical treatment for non-selective case with postinfarction ventricular septal rupture / 北京大学学报(医学版)

OBJECTIVE@#To observe the clinical prognosis and surgical treatment results in patients with postinfarction ventricular septal rupture, and to discuss the risk factors, methods & timing of treatment.@*METHODS@#From January 2006 to February 2019, 23 patients with postinfarction ventricular septal rupture were admitted to the department of cardiac surgery, Peking University People's Hospital, including 12 males (52.2%) and 11 females (47.8%), aged (64.26 ±11.09) years. Among them, 18 cases underwent operation, and 5 cases did not receive surgical treatment. The clinical data and follow-up data were summarized retrospectively.@*RESULTS@#Among the patients treated with operation, the average time from perforation to operation was (19.39 ±13.67) d, including 6 cases (33.3%) of perforation within 1 week, 6 cases (33.3%) within 2 to 4 weeks and 6 cases (33.3%) more than 4 weeks. Emergency surgery was performed in 11 cases (61.1%) because of hemodynamic instability, and selective operation in 7 cases (38.9%). Direct enlarged patch was used in 13 cases (72.2%), and some infarct exclusion techniques were used in 5 patients (27.8%). In 18 cases, coronary artery bypass grafting was performed in 12 cases (66.7%). Of all the surgical patients, 7 (38.9%) died during hospitalization. Compared with the survival patients, the perioperative death patients had earlier perforation [(1.83±0.75) d vs. (5.22 ±4.66) d, P=0.019] and higher emergency operation rate (100% vs. 36.4%, P=0.009) and lower simultaneous bypass grafting rate (28.6% vs. 90.1%, P=0.008). The median follow-up time was 2 years (3 months to 10 years). 2 patients died of heart failure in 2 months after operation, and 9 cases (50.0%) survived for a long time. Of the 5 patients who had not been treated, 2 died while waiting for operation, and 3 patients who refused surgery died within 1 week after discharge.@*CONCLUSION@#Surgery is an effective treatment for patients with acute myocardial infarction complicated with ventricular septum perforation. The best time for operation should be determined by real-time evaluation and monitoring, combined with the situation of patients. Concomitant coronary artery bypass grafting may be beneficial to these patients.

Survival Analysis of Off-pump Coronary Artery Bypass Grafting in Patients Aged Over 75 / 中国循环杂志

Objectives:To describe the early and long-term survival of off-pump coronary artery bypass grafting(OPCAB)and to analyze the impact and risk factors of peri-operative events on mortality and long-term survival in OPCAB patients aged over 75 years old. Methods:From January 2001 to December 2012,233 patients aged over 75 underwent OPCAB in our hospital, 173 cases (74.25%) were male,the average age was (77.1±2.3) years.The perioperative data was retrospectively collected.Binary Logistic regression was used to define the risk factors related to the perioperative events and mortality.Follow-up was performed regularly post-surgery. Univariate analysis and Cox regression model were used to find out factors affecting the long-term outcomes. Results:Fifteen out of 233 patients died during the perioperative period. Binary Logistic regression showed that preoperative arrhythmia (OR=6.767, P=0.002),IABP ( intraoperative, post-operative) (OR=4.292, P=0.040;OR=19.455, P＜0.001), ICU stay time (OR=1.500, P=0.001), mechanical ventilation time (OR=1.004, P=0.002), reintubation or tracheotomy (OR=30.000, P＜0.001), re-thoracotomy (OR=26.750, P＜0.001), postoperative cerebral infarction (OR=5.889, P=0.041) were risk factors of perioperative mortality. The remaining 218 patients were followed up for a mean of (92.84±45.52) months, 121 patients died during follow-up. The survival rate at l, 3, 5, 8 and 10 years was 90.99%, 87.55%, 85.31%, 68.93% and 56.70%, respectively. Univariate analysis showed that sex(male), hypertension, preoperative arrhythmia, reintubation or tracheotomy were risk factors of the long-term mortality (P＜0.05). Cox regression analysis showed that reintubation or tracheotomy (HR 4.387, 95%CI=1.876-10.259,P＜0.010) was the independent risk factor affecting the long-term survival. Conclusions:Preoperative arrhythmia, IABP (intraoperative, postoperative), ICU stay time, mechanical ventilation time, reintubation and tracheotomy, re-thoracotomy, postoperative cerebral infarction are risk factors of perioperative mortality. Reintubation or tracheotomy is the independent risk factor affecting the long-term survival.Taken together, OPCAB in patients aged over 75 is associated with favorable perioperative and long-term outcome,and it serves a safe and effective operative strategy for coronary artery revascularization in patients aged over 75.

Excitability of cortical neurons and their neural network / 中国药理学与毒理学杂志

The cerebral cortex contains a large variety of neuronal cells, which connect with each other via synapses to form different neural networks and fundamental elements for brain functions such as sense, movement, learning, language and decision making. Information processing in the cerebral cortex requires the activation of individual neurons and their recurrent networks,that is,the generation of action potential (AP) (excitability of single neurons) and network activity (excitability of neural networks).Initiation of AP occurs at the axon and is determined by axonal ion channels as well as intrinsic biophysical properties.The excitability of recurrent networks is not only determined by the excitability of different types of neurons, but also regulated by the unique properties of neurotransmitter release in distinct synapses including excitatory and inhibitory ones.Traditionally,it is believed that the all-or-none AP is the only mode of information transmission-digital mode.Recent studies have shown that the subthreshold membrane potential fluctuations regulate AP-induced the synaptic transmission-analog mode. At the network level, the network activity is relatively stable, resulting from a dynamic balance of excitation and inhibition. The microcircuits of recurrent inhibition mediated by distinct inhibitory interneuron types and the modes of synaptic transmission,such as the analog mode of signal communication and asyn-chronous neurotransmitter release,play critical roles in maintaining the excitation and inhibition balance. Together,we present here some new insights into the mechanisms underlying the excitability of distinct types of cortical neurons and their interconnected networks.

Incidence and short-term outcome of physiologic bronchopulmonary dysplasia in very preterm infants / 中华实用儿科临床杂志

Objective To investigate the incidence and short-term outcome of very preterm infants with physiologic bronchopulmonary dysplasia (BPD).Methods Data of very preterm infants with gestational age of no more than 32 weeks admitted into Guangdong General Hospital between Mar.2011 and Feb.2012 were prospectively collected.Oxygen withdrawing test was performed in these infants at postmenstrual age of 36 weeks.Infants who failed to pass the test or who were ventilated were diagnosed as physiologic BPD.Results Sixty-six infants were admitted,of whom 6 were excluded for more than 36 weeks of postmenstrual age at admission.Eighteen infants(30.0％) were diagnosed as classic BPD.Among them,at testing time point,4 cases did not need supplemental oxygen,13 cases needed oxygen sup-plementation and 1 case needed mechanical ventilation.Thirteen infants underwent oxygen withdrawing test and 6 cases passed.Eight cases (13.3％) were diagnosed as physiologic BPD.The incidences of apnea or bradycardia were of no differences between infants passing or failing to pass oxygen withdrawing test.All infants survived to discharge without supplemental oxygen.Conclusions The incidence of infants with physiologic BPD is significantly lower than that with classic BPD.Restrictive saturation of percutaneous oxygen can decrease the incidence of infants with supplemental oxygen,with no more adverse events.More research are needed on physiologic BPD.

Airway obstruction caused by large blood vessel anomalies: assessment by flexible bronchoscopy / 中华儿科杂志

<p><b>OBJECTIVE</b>To evaluate the diagnostic value and safety of flexible bronchoscopy in congenital great vessel diseases complicated with airway compression.</p><p><b>METHOD</b>The medical records of patients with great vessels abnormalities who were admitted to the neonatal intensive care unit (NICU) from October 2005 to June 2009 were retrospectively reviewed; 34 cases were diagnosed as airway compression by flexible bronchoscopy, 10 cases as vascular ring, 24 cases as aortal arch obstruction. The age of the patients was 6 d - 11 m, body weight 2.2 - 8.7 kg [(4.6 +/- 1.4) kg]. Recorded airway abnormalities detected by bronchoscopy and CT, cardiac vascular defects and airway compression were consistent with the findings on operation. The relation between the airway compression and cardiac vascular abnormalities, treatment of the airway compression and outcome were analysed.</p><p><b>RESULT</b>Bronchoscopic assessment was successfully performed in NICU or operating room for all the patients. (1) Initial presentation of the 34 cases were tachypnea, stridor, refractory lung infection and prolonged mechanical ventilation. (2) Extrinsic compression was found in all the 10 cases with vascular ring by bronchoscopy initially which indicated vascular ring, airway compression was mainly of lower part of trachea. Diagnosis of 9 cases was consistent with CT diagnosis and in 1 case the diagnosis was confirmed by surgery; among these cases, 7 had congenital tracheal stenosis. (3) In the 24 cases with aortic obstructive lesion, 5 were detected to have tracheal stenosis by CT before correction of vascular abnormality, among whom one case was indicated to have tracheal stenosis by bronchoscopy, the other 19 cases were found with airway compression by bronchoscopy during or after vascular correction. Among the 24 cases, 21 had left main bronchial stenosis, 2 had congenital tracheal stenosis. Airway compression diagnosed by bronchoscopy agreed with the findings of CT. Two cases developed transient decrease of oxygen saturation, 5 cases developed transient tachycardia.</p><p><b>CONCLUSION</b>Flexible bronchoscopy plays an important role in assessment of the airway compression complicated with great vessel abnormalities. Bronchoscopy is an accurate, convenient, safe and rapid way for airway assessment, but further examination of the peripheral structure and vascular malformation need combined examination with CT.</p>

Evaluation of Diagnosis and Preoperative Management of 53 Cases with Interrupted Aortic Arch in Infancy / 实用儿科临床杂志

Objective To evaluate diagnosis and preoperative management of cases with interrupted aortic arch(IAA)in infancy.Methods Fifty-three infants who were admitted to our hospital from Jan.2001 to Nov.2007 were involved.Clinical data,findings of echocardiogram(Echo),spiral CT,MRI,angiocardiography,preoperative management,surgical repair and postoperative outcome were analyzed retrospectively.Results There were 38 boys and 15 girls,weighted 2.18-10.0(4.32?1.60)kg,aged 1 day to 12(3.05?3.53)months,of which 50.94% were neonates.Symptoms at presentation were 90.57% with tachypnea and 83.02% with difficulty in feeding.Eighty three point zero two percentage cases had different degree of congestive heart failure,37.74% of which were in grade Ⅲ heart function.All cases had weakened femoral pulse.All cases were performed Echo,38 cases of them diagnosed as IAA,6 cases as IAA or severe coarctation of aorta(CoA);they were diagnosed as IAA by CT,and 9 as severe CoA who were diagnosed as IAA via CT or operation.Thirty-three cases were performed CT,of which 15 underwent surgical repair,cardiovascular abnormalities revealed by CT were the same as those in surgical findings.Three cases were taken MRI,and 7 cases were performed angiocardiography.According to the results of Echo,CT,MRI,angiocardiography and surgical findings,35 cases were type A,15 cases were type B and 3 cases were type C.Preoperative treatment included maintaining patent ductus areriosis,management of heart failure and supportive treatment.After proper preoperative management of medication,most cases with congestive heart failure were improved.Twenty-six cases underwent surgical repair,16 survived,10 died du-ring perioperative stage.Main cause of death was severe low cardiac output.Conclusions Value of Echo in diagnosis of IAA is limi-ted.Combination of Echo with CT or MRI is a convenient and safe way to diagnose IAA,it can replace the traditional method of Echo combined with angiocardiography.Proper preoperative management is helpful to patients with IAA to pass to surgical repair,and makes for successful operation.