Pneumonia relevant to lung transplantation and pathogen distribution / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Pneumonia is the most common cause of morbidity and mortality in lung transplant (LT) recipients. The aim of the present study was to evaluate the incidence, etiology, risk factors and prognosis of pneumonia in LT recipients.</p><p><b>METHODS</b>The LT cohort consisted of 28 recipients receiving LT in Beijing Chao-Yang Hospital from August 2005 to April 2011. Data collected included demographic data, underlying disorders, time and type of transplant, follow-up information, date of last follow-up, and patient status. A retrospective analysis was made of observational data that were prospectively collected.</p><p><b>RESULTS</b>Twenty-two patients of 28 LT recipients had 47 episodes of pneumonia throughout the study period. Thirtyeight episodes of pneumonia in 19 recipients occurred post-LT with a median follow-up of 257.5 days (1-2104 days), the incidence of pneumonia was 192.4 episodes per 100 LT/year and its median time of onset was 100.5 days (0-946 days) post-transplantation. Bacteria, virus and fungi accounted for 62%, 16% and 15% of the microbial pathogens, respectively. The most frequent were Pseudomonas aeruginosa (20%), cytomegalovirus (CMV) (15%), and Aspergillus fumigatus (10%). A total of 29% (11/38) of pneumonias occurred in the first month post-LT, and then the incidence decreased gradually. The incidence of CMV pneumonia was 25% (7/28) with a median time of 97 days (10-971 days). More than one bacterial infection and CMV infection were independent risk factors for aspergillus infection. The incidence of pulmonary tuberculosis (TB) was 18% (5/28), and the history of TB was a risk factor for TB relapse. There were 58% (7/12) of recipients who died of infection, and 71% (5/7) of these died in the first year after LT.</p><p><b>CONCLUSIONS</b>Pneumonia is still a major cause of morbidity and mortality in LT recipients. The most frequent microorganisms were Pseudomonas aeruginosa, CMV, and Aspergillus fumigates. The incidence of CMV pneumonia decreases with a delayed median time of onset. More than one incidence of bacterial infection and CMV infection are independent risk factors for aspergillus infection. LT recipients are at high risk for TB, and the history of TB is a risk factor for TB relapse.</p>

Propofol may protect PC12 cells from β-amyloid₂₅₋₃₅ induced apoptosis through the GSK-3β signaling pathway / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>There are two major pathological hallmarks of Alzheimer's disease. One is the progressive accumulation of beta-amyloid (Aβ) in the form of senile plaques; the other is hyperphosphorylated tau, causing neuronal apoptosis. Some inhalation anesthetics, such as isoflurane and desflurane, have been suggested to induce Aβ accumulation and cause AD-like neuropathogenesis. Whether intravenous anesthetics have similar effects is still unclear. We therefore set out to determine the relationship between propofol and AD-like pathogenesis.</p><p><b>METHODS</b>PC12 cells were cultured in serum-free medium for 12 hours prior to drug treatment. Various concentrations from 5 µmol/L to 80 µmol/L of aggregated Aβ25-35 were added to determine a proper concentration for further study. After exposure to 10 µmol/L Aβ25-35 alone or with 20 µmol/L propofol for 6 hours, PC12 cell viability was determined by MTT assay. Western blotting and immunocytochemical staining were performed to observe the protein expression of the Bcl-2 family, tau phosphorylation at different sites, and tau protein kinases and phosphatases.</p><p><b>RESULTS</b>Aβ25-35 induced a decrease in PC12 cell viability in a dose-dependent manner. Exposure to 10 µmol/L Aβ25-35 for 6 hours resulted in the mild cell survival, accompanied by a decline in Bcl-2, and an increase in phosphorylation of GSK-3β and tau at different sites. Compared with the Aβ25-35 group, cells treated with propofol alone showed no significant difference, while cells co-incubated with propofol and Aβ25-35 showed a significantly higher survival rate (P < 0.01 or P < 0.05). Tau phosphorylation at Ser396, Ser404 and Thr231 and the level of GSK-3β in PC12 cells increased after exposure to 10 µmol/L Aβ25-35. Co-incubation with propofol attenuated cellular apoptosis by inhibiting tau phosphorylation.</p><p><b>CONCLUSIONS</b>These data indicate that propofol may protect PC12 cells from Aβ25-35-induced apoptosis and tau hyperphosphorylation through the GSK-3β pathway, therefore it may be a safer anesthesia for AD and elderly patients.</p>

Serum proteomics of early postoperative cognitive dysfunction in elderly patients / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Studies on postoperative cognitive dysfunction (POCD) have attracted extensive attention and achieved significant progress. However, the diagnosis of POCD is not very satisfactory as no specific biomarkers have been classified. The aim of the present study was to evaluate differences in serum protein composition between POCD and Non-POCD patients, identify potential biomarkers associated with early POCD, and study the mechanism underlying POCD.</p><p><b>METHODS</b>Sixty-eight elderly patients (age ≥ 65 years) received isoflurane inhalation anesthesia for arthroplasty surgeries. One day before and seven days after the surgery, these patients were subjected to a neuropsychological test and venous blood sample collection. Postoperative cognitive dysfunction was determined using Z test scores. Based on the results, the patients were divided into POCD and non-POCD groups. Twenty-five randomly chosen blood samples obtained seven days after the surgery from each group were analyzed on a Bruker ultraFlex(TM) time of flight (TOF)/TOF mass spectrophotometer. The resulting peptide fingerprints were compared with those from the pre-surgery samples to identify differences in serum protein composition. The model designed to distinguish between a non-POCD group and a POCD group were established and validated. Three proteins with the most significant changes were selected for further characterization.</p><p><b>RESULTS</b>Thirty-three cases were diagnosed as POCD. Using the Clinprotools software, 58 polypeptides were found to display differential expression (P < 0.05). Using a support vector algorithm method, seven differential peaks were isolated to establish a diagnostic model to distinguish POCD patients from normal individuals. The prediction rate and recognition rate were 96.89% and 100%, respectively. Validation of this model showed that the accuracy rates were 100% and 85% using samples from the POCD and non-POCD groups, respectively. Protein analysis also led to the identification of fibrinopeptide A (FPA) as a potential biomarker for POCD.</p><p><b>CONCLUSIONS</b>Arthroplastic surgery under isoflurane inhalation anesthesia causes differential serum protein expression in elderly patients. These differentially expressed proteins may contribute to the diagnosis of early POCD, which may provide a basis for identifying the underlying mechanism of POCD development.</p>

Effects of the novel 6% hydroxyethyl starch 130/0.4 on renal function of recipients in living-related kidney transplantation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The optimal colloid for use during kidney transplantation is not clear. Patients undergoing living-related kidney transplantation (LRKT) were used to compare the protective effects of 6% hydroxyethyl starch 130/0.4 (HES 130/0.4) and 4% succinylated gelatine, as donor kidney procurement, ischemia time and surgical conditions are comparable. Stroke volume variation (SVV) was used to monitor intravascular volume to avoid renal allograft hypoperfusion.</p><p><b>METHODS</b>Eighty patients undergoing LRKT were divided into two groups: group H received 6% HES 130/0.4 and group G received 4% succinylated gelatine. All donors and recipients received 15 - 25 ml/kg of the relevant colloid during surgery. Arterial blood pressure (ABP), heart rate (HR), central venous pressure (CVP), SVV and cardiac index (CI), electrocardiography (ECG) and SpO2 were monitored continuously. SVV was kept between 6% - 13% and mean arterial pressure at 100 - 130 mmHg. Samples of venous blood and urine were obtained 30 minutes after unclamping and on the mornings of post-operative days (POD) 1 - 4 to measure serum and urine β2-microglobulin, urine α1-microglobulin, microalbumin and N-acetyl-β-D-glucosaminidase. Blood urea nitrogen (BUN) and creatine were determined pre-operation (t(0)), 3 hours after surgery (t(1)) and on PODs 1 (t(2)), 2 (t(3)), 4 (t(4)), 7 (t(5)) and 10 (t(6)). Urine output was recorded at t(1), t(2), t(5), t(6).</p><p><b>RESULTS</b>Age, body weight, body surface area (BSA), operation time, urine output and the colloid volume infused were comparable between the groups and hemodynamics were stable during surgery. BUN, serum creatine, serum β2-microglobulin and urine β2-microglobulin decreased significantly after surgery in both groups relative to the baseline. BUN decreased significantly in group H compared with group G at t(1), t(2) and t(4). Urine microalbumin decreased significantly in group H on POD 4 compared with group G. Urine α1-microglobulin was not significantly different between the two groups.</p><p><b>CONCLUSION</b>Both colloids can be safely used for LRKT, but HES130/0.4 was associated with a more rapid recovery of renal function.</p>

Assessment of right ventricular function by pressure-volume loops in off-pump coronary artery bypass surgery / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Right ventricular function plays an important role in the hemodynamic derangement during off-pump coronary artery bypass (OPCAB) surgery. Pressure-volume loops have been shown to provide load-independent information of cardiac function. Therefore, the aim of this study was to investigate the feasibility of construction of right ventricular pressure-volume loops with pressure and volume data measured by a volumetric pulmonary artery catheter (PAC) and to evaluate right ventricular systolic and diastolic function by end-systolic elastance (E(ES)) and end-diastolic stiffness (E(ED)) in OPCAB surgery.</p><p><b>METHODS</b>Twenty-eight patients who underwent OPCAB surgery were included. After anesthesia induction, a volumetric PAC was placed via the right internal jugular vein. Data were recorded at: anesthesia steady-state before skin incision (T1); 5 minutes after the stabilizer device was placed for anastomosis on the heart's anterior wall (T2), lateral wall (T3), posterior wall (T4), respectively; after sternal closure (T5). Three sets of data were collected at each time point: first, hemodynamic variables were measured; second, right ventricular E(ES) and E(ED) were calculated; third, right ventricular pressure-volume loops were constructed with pressure and volume data measured from end-diastole point, end-isovolumic systole point, peak-ejection point, end-systole point and end-isovolumic diastole point.</p><p><b>RESULTS</b>Right ventricular pressure-volume loops generally shifted to the left during OPCAB surgery. Especially, the end-diastolic point shifted upward and to the left at T2-T5 compared with that at T1. Decrease in right ventricular ejection fraction, stroke volume index and end-diastolic volume index occurred (P < 0.05) at T4 compared with values at T1. Pulmonary vascular resistance index at T4 increased relatively compared with that at T2 and T3. The change of E(ES) was not statistically significant during operation. Right atrial pressure increased only during coronary anastomoses (T2-T4, P < 0.05), whereas E(ED) increased throughout OPCAB surgery (P < 0.05).</p><p><b>CONCLUSIONS</b>Right ventricular pressure-volume loops can be constructed using a volumetric PAC. Right ventricular systolic dysfunction occurred during anastomoses on the heart's posterior wall not due to impaired myocardial contractility but as a result of reduced preload and a relative increase in afterload. Right ventricular diastolic function was impaired throughout OPCAB surgery.</p>

Spinal release of the amino acids with a time course in a rat model of postoperative pain / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The mechanisms underlying postoperative pain remain unclear. Neurotransmitters of excitatory and inhibitory amino acids play an important role in the transmission and modulation of pain in the spinal dorsal horn. This study aimed to investigate the changes of release of excitatory and inhibitory amino acids in the spinal cord during postoperative pain and to provide a novel theoretical basis for postoperative pain management.</p><p><b>METHODS</b>Loop microdialysis catheters were implanted subarachnoidally via the atlanto-occipital membrane in 16 healthy Sprague-Dawley rats. All rats without neural deficits were divided into two groups, Group A and Group B, following 5 days of recovery. The tubes for microdialysis were connected and 25 microl microdialysate sample for baseline value was collected after one-hour washout in each rat. A plantar incision in the right hind paws of rats in Group A were performed under 1.2% isoflurane. All rats in Group B were only anesthetized by 1.2% isoflurane for the same duration. The microdialysate samples were collected at 3 hours, 1 day, 2 days and 3 days after the incision (or isoflurane anesthesia in Group B) in both groups. The cumulative pain scores were also assessed at the above time-points. The amino acids in the microdialysate samples were tested using high performance liquid chromatography.</p><p><b>RESULTS</b>Within Group A, the release of aspartate and glutamate at 3 hours after the incision was significantly higher than the baseline values and the release of glycine at 1 day after the incision significantly increased compared with the baseline values (P < 0.01). Within Group B, the release of neurotransmitters at each time point had no significant difference compared with the baseline values (P > 0.05). The release of aspartate and glutamate at 3 hours after the incision in Group A was significantly higher than that in Group B (P < 0.01). The release of glycine at 1 day after the incision in Group A significantly increased compared with Group B (P < 0.01). The cumulative pain scores at 3 hours, 1 day and 2 days after the incision in Group A were significantly higher than those in Group B (P < 0.01).</p><p><b>CONCLUSIONS</b>The release of the excitatory amino acids occurs in the early phase of postoperative pain and might not be involved in the maintenance of pain in a rat model of incision pain. The release of inhibitory glycine lagged behind the excitatory amino acids. The implication of inhibitory glycine release remained to be established further.</p>

Can bispectral index or auditory evoked potential index predict implicit memory during propofol-induced sedation? / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Some patients still suffer from implicit memory of intraoperative events under adequate depth of anaesthesia. The elimination of implicit memory should be a necessary aim of clinical general anaesthesia. However, implicit memory cannot be tested during anaesthesia yet. We propose bispectral index (BIS) and auditory evoked potential index (AEPI), as predictors of implicit memory during anaesthesia.</p><p><b>METHODS</b>Thirty-six patients were equally divided into 3 groups according to the Observer's Assessment of Alertness/Sedation Score: A, level 3; B, level 2; and C, level 1. Every patient was given the first auditory stimulus before sedation. Then every patient received the second auditory stimulus after the target level of sedation had been reached. BIS and AEPI were monitored before and after the second auditory stimulus presentation. Four hours later, the inclusion test and exclusion test were performed on the ward using process dissociation procedure and the scores of implicit memory estimated.</p><p><b>RESULTS</b>In groups A and B but not C, implicit memory estimates were statistically greater than zero (P < 0.05). The implicit memory scores in group A did not differ significantly from those in group B (P > 0.05). Implicit memory scores correlated with BIS and AEPI (P < 0.01). The area under ROC curve is BIS > AEPI. The 95% cutoff points of BIS and AEPI for predicting implicit memory are 47 and 28, respectively.</p><p><b>CONCLUSIONS</b>Implicit memory does not disappear until the depth of sedation increases to level 1 of OAA/S score. Implicit memory scores correlate well with BIS and AEPI during sedation. BIS is a better index for predicting implicit memory than AEPI during propofol induced sedation.</p>

Investigation and analysis of incidence of awareness in patients undergoing cardiac surgery in Beijing, China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Awareness under general anesthesia is a serious complication which leads to psychiatric disorders. The incidence of awareness in patients undergoing cardiac surgery has been reported in as many as 1.5% - 23% in foreign countries. But so far, medical literature about awareness during cardiac surgery is still rare in China. Therefore, we investigated the incidence of awareness in patients undergoing different kinds of cardiac surgery, the phases when awareness occurred and the effect of cardiopulmonary bypass on the incidence of awareness in coronary artery bypass grafting in Beijing.</p><p><b>METHODS</b>Patients' recall of awareness during cardiac surgery was assessed. One hundred patients undergoing coronary artery bypass grafting (CABG) in Chaoyang Hospital, Beijing, one hundred patients undergoing CABG and one hundred patients undergoing valve replacement or septal defect repair in Fuwai Hospital, Beijing, were interviewed 3-6 days after surgery. Every report about patients on recall of awareness was recorded. An independent research team, blinded to patients' surgery and anesthesia, assessed every report of awareness.</p><p><b>RESULTS</b>The incidence of awareness of patients received CABG under cardiopulmonary bypass (CPB), off -pump CABG, septal repair or valve replacement under CPB was 4.7% (5 of 106 cases), 9.6% (9 of 94 cases) and 4% (4 of 100 cases), respectively. CPB did not greatly affect the incidence of awareness during the period of CABG (P > 0.05). The incidence of awareness of patients who received CABG under CPB did not increase significantly, in comparison with that of patients who received septal repair or valve replacement under CPB in Fuwai Hospital (P > 0.05). Awareness easily occurred before bypass grafting or CPB.</p><p><b>CONCLUSIONS</b>Awareness mainly occurs before bypass grafting or CPB in cardiac surgery. Most cases with awareness have auditory perceptions. CPB is not a main factor which affects the incidence of awareness of CABG. Surgical types do not affect the incidence of awareness of patients under CPB.</p>