Live birth after cervical ectopic uterus transplantation in mice

An ideal animal model is a prerequisite for the basic research of uterus transplantation. This study aimed to develop a new cervical ectopic uterus transplantation mice model, which was established by vascular anastomosis of the right common iliac artery and vein of the donor with the right common carotid artery and external jugular vein of the recipient, respectively, using the cuff method. The survival status of the transplanted uterus was assessed by macroscopic observation and histological examination after surgery, and the function of the graft uterus was tested by verifying whether the pregnancy is possible. A total of 40 transplants were performed, of which only 1 failed due to donor hemorrhage. After 26 transplants, the total operation time reduced to 52.4 ± 3.8 minutes, of which the total ischemia time took 6.6 ± 1.1 minutes. Sixty days after transplantation, all the graft uteri had a good blood supply and spontaneous contraction. The histology showed no significant difference between the transplanted uterus and the native. Embryo transfer experiments have proven that the transplanted uterus has uterine function. In conclusion, this new model is an effective and simple mice model for the studies of the scientific issues related to uterus transplantation.     

Brain‐dead donor heart conservation with a preservation solution supplemented by a conditioned medium from mesenchymal stem cells improves graft contractility after transplantation

Hearts are usually procured from brain‐dead (BD) donors. However, brain death may induce hemodynamic instability, which may contribute to posttransplant graft dysfunction. We hypothesized that BD‐donor heart preservation with a conditioned medium (CM) from mesenchymal stem cells (MSCs) would improve graft function after transplantation. Additionally, we explored the PI3K pathway's potential role. Rat MSCs‐derived CM was used for conservation purposes. Donor rats were either exposed to sham operation or brain death by inflation of a subdural balloon‐catheter for 5.5 hours. Then, the hearts were explanted, stored in cardioplegic solution‐supplemented with either a medium vehicle (BD and sham), CM (BD + CM), or LY294002, an inhibitor of PI3K (BD + CM + LY), and finally transplanted. Systolic performance and relaxation parameters were significantly reduced in BD‐donors compared to sham. After transplantation, systolic and diastolic functions were significantly decreased, terminal deoxynucleotidyl transferase‐mediated dUTP nick end‐labeling (TUNEL)‐positive cells and endonuclease G positive cells were increased in the BD‐group compared to sham. Preservation of BD‐donor hearts with CM resulted in a recovery of systolic graft function (dP/dt_max: BD + CM: 3148 ± 178 vs BD: 2192 ± 94 mm Hg/s at 110 µL, P < .05) and reduced apoptosis. LY294002 partially lowered graft protection afforded by CM in the BD group. Our data suggest that PI3K/Akt pathway is not the primary mechanism of action of CM in improving posttransplant cardiac contractility and preventing caspase‐independent apoptosis.     

Risk factors for late-onset ventilator-associated pneumonia in trauma patients receiving selective digestive decontamination

Objective To determine the independent risk factors for late-onset ventilator-associated pneumonia (VAP) in trauma patients receiving selective digestive decontamination (SDD).Design A 4-year, prospective cohort study of trauma patients meeting the following criteria: injury severity score >15, and duration of mechanical ventilation >5 days. Predictors of late-onset VAP occurrence were assessed by logistic regression analysis.Population All patients received SDD consisting of polymixin E, gentamicin, and amphotericin B applied in nostrils, mouth, and gut with a 3-day course of parenteral cefazolin. VAP was suspected on clinical and radiological signs, and confirmed by the presence of at least one microorganism at a concentration of at least 10⁴ CFU/ml on the broncho-alveolar lavage.Measurement Independent risk factors for late-onset VAP.Results A late-onset VAP was diagnosed in 90 (56%) out of 159 patients. Predicting factors for late-onset VAP were: use of non-depolarizing muscle relaxant agents for intubation [3.4 (CI 1.08–10.73)], duration of intubation [1.06 (CI 1.01–1.17)], length of intensive care unit (ICU) stay [1.05 (CI 1.02–1.09)], and prior tracheal colonization [1.03 (CI 1.02–1.21)]. Exposure to prior antimicrobial treatment, except SDD, conferred protection [0.3 (0.12–0.74)].Conclusion This study confirms the role of duration of intubation, length of ICU stay, and prior tracheal colonization in the development of late-onset VAP. The results also highlight the importance of the initial management on the development of late-onset VAP. The type of neuromuscular blocking agents to intubate trauma patients should be evaluated in future studies.     

天鹅型记忆接骨器三维模型的构建及其生物力学意义

目的介绍天鹅型记忆接骨器(swan-likememorycompressionconnector,SMC)三维模型的构建并进行三维有限元计算及分析,探讨相关的记忆生物力学意义。方法采用大型有限元分析软件ANSYS5.6,通过拆分SMC,分别将5部分建模后,生成体积从而建立SMC三维模型。结果所构建SMC三维模型,逼真反映SMC的真实形态及生物力学行为,同时与肱骨模型有较高的帖服。结论SMC三维有限元模型的构建,可以为SMC治疗肱骨骨折骨不连的力学行为以及SMC相关力学基础研究提供精确模型。     

Principle components analysis of pain thresholds to thermal, electrical, and mechanical stimuli suggests a predominant common source of variance

We addressed the question whether pain thresholds to different stimuli measure independent aspects of pain or one common phenomenon. In the first case, different stimuli are required to completely characterize a subject’s pain sensitivity. In the second case, different stimuli are redundant and can be used to calculate composite scores across pain modalities. We measured pain thresholds to several stimuli (heat, heat/capsaicin, cold, cold/menthol, blunt pressure, 5-Hz sine-wave electric current (0–20 mA), punctate pressure (von Frey hairs), and von Frey hairs plus capsaicin application) in 45 healthy men and 32 healthy women (aged 20–44 years). We observed that pain thresholds were significantly correlated with each other. Principal component analysis indicated that their variance was attributable more to the difference in subjects (variance estimate: 0.393) than to the difference in pain stimuli within a subject (variance estimate: −0.008). Among three principal components of the intercorrelation matrix with eigenvalues >1, the first, explaining 48% of the total variance, carried high loadings from all stimuli indicating that they shared a common source of half of their variance. Only minor variance components, each explaining <14% of the total variance, indicated a distinction of pain stimuli. There, a pattern of similarities and dissimilarities emerged agreeing with known distinct mechanisms of nociceptive responses to different stimuli. We conclude that characterizing a person as being generally stoical or complaining to any painful stimulus appears to be justified at least at pain threshold level.     

Nonstationary noise estimation in functional MRI

An important issue in functional MRI analysis is accurate characterisation of the noise processes present in the data. Whilst conventional fMRI noise representations often assume stationarity (or time-invariance) in the noise generating sources, such approaches may serve to suppress important dynamic information about brain function. As an alternative to these fixed temporal assumptions, we present in this paper two time-varying procedures for examining nonstationary noise structure in fMRI data. In the first procedure, we approximate nonstationary behaviour by means of a collection of simple but numerous time-varying parametric models. This is accomplished through the derivation of a locally parametric AutoRegressive (AR) plus drift model which tracks temporal covariance by allowing the model parameters to evolve over time. Before exploring time variation in these parameters, window-widths (bandwidths) that are well suited to the latent time-varying noise structure must be determined. To do this, we employ a bandwidth selection mechanism based on Stein's Unbiased Risk Estimator (SURE) criterion. In the second procedure, we describe the fMRI noise using a nonparametric method based on Functional Data Analysis (FDA). This process generates well-conditioned nonstationary covariance estimates that reflect temporal continuity in the underlying data structure whilst penalizing effective model dimension. We demonstrate both methods on simulated data and investigate the presence of nonstationary noise in resting fMRI data using the whitening capabilities of the locally parametric procedure. We evaluate the comparative behaviour of the stationary and nonstationary AR-based methods on data acquired at 1.5, 3 and 7 T magnetic field strengths and show that incorporation of time variation in the AR parameters leads to an overall decrease in the level of residual structure in the data. The FDA noise modelling technique is formulated within an activation mapping procedure and compared to the SPM (Statistical Parametric Mapping) toolbox on a cognitive face recognition task. Both the SPM and FDA methods show good sensitivity on this task, but we find that inclusion of the nonstationary FDA noise model seems to improve detection power in important task-related medial temporal regions.     

A Daily Life Comparison of Sociotropy-Autonomy and Hopelessness Theories of Depression

The hopelessness theory and Beck’s cognitive theory of depression were compared, controlling for other factors associated with mood change and stress reactivity. Using a high-risk design, 179 individuals were selected based on cognitive vulnerabilities and substance use frequency. Assessments of mood, daily events, and specific attributions were acquired using the Experience Sampling Method. Strong support was found for attributional style and sociotropy as indirect determinants of depressed mood, as well as for the notions of causal mediation and vulnerability specificity. Hopelessness theory explained a slightly larger portion of variance in depressed mood overall. The personality diatheses described by either theory were largely independent of each other and their mechanisms of action were not influenced by depression history or substance use.