The shoulder abductor strength is a novel predictor of tracheostomy in patients with traumatic cervical spinal cord injury.

BACKGROUND: Early prediction of tracheostomy in traumatic cervical spinal cord injury (TCSCI) patients is often difficult. This study aims to clarify the association between shoulder abductor strength (SAS) and tracheostomy in patients with TCSCI. METHODS: We retrospectively analyzed 513 TCSCI patients who were treated in our hospital. All patients were divided into a tracheostomy group and a non-tracheostomy group. The SAS was assessed using the Medical Research Council (MRC) Scale for Muscle Strength grading. Potential predictors were assessed for their association with tracheostomy in patients. A nomogram was developed based on multivariable logistic regression analysis (MLRA) to visualize the predictive ability of the SAS. Validation of the nomogram was performed to judge whether the nomogram was reliable for visual analysis of the SAS. Receiver operating characteristics curve, specificity, and sensitivity were also performed to assess the predictive ability of the SAS. RESULTS: The proportion of patients with the SAS grade 0-2 was significantly higher in the tracheostomy group than in the non-tracheostomy group (88.1% vs. 54.8%, p = 0.001). The SAS grade 0-2 was identified as a significant predictor of the tracheostomy (OR: 4.505; 95% CI: 2.080-9.758; p = 0.001). Points corresponding to both the SAS grade 0-2 and the neurological level of injury at C2-C4 were between 60 and 70 in the nomogram. The area under the curve for the SAS grade 0-2 was 0.692. The sensitivity of SAS grade 0-2 was 0.239. The specificity of SAS grade 0-2 was 0.951. CONCLUSIONS: SAS is a novel predictor of tracheostomy in patients after TCSCI. The SAS grade 0-2 had a good predictive ability of tracheostomy.

Association of RDM1 with osteosarcoma progression via cell cycle and MEK/ERK signalling pathway regulation.

RAD52 motif-containing 1 (RDM1), a key regulator of DNA double-strand break repair and recombination, has been reported to play an important role in the development of various human cancers, such as papillary thyroid carcinoma, neuroblastoma and lung cancer. However, the effect of RDM1 on osteosarcoma (OS) progression remains unclear. Here, this study mainly explored the connection between RDM1 and OS progression, as well as the underlying mechanism. It was found that RDM1 was highly expressed in OS cells compared with human osteoblast cells. Knockdown of RDM1 caused OS cell proliferation inhibition, cell apoptosis promotion and cell cycle arrest at G1 stage, whereas RDM1 overexpression resulted in the opposite phenotypes. Furthermore, RDM1 silencing leads to a significant decrease in tumour growth in xenograft mouse model. RDM1 also increased the protein levels of MEK 1/2 and ERK 1/2. All these findings suggest that RDM1 plays an oncogenic role in OS via stimulating cell cycle transition from G1 to S stage, and regulating MEK/ERK signalling pathway, providing a promising therapeutic factor for the treatment of OS.

SPECT Imaging of 2-D and 3-D Distributed Sources with Near-Field Coded Aperture Collimation: Computer Simulation and Real Data Validation.

The imaging of distributed sources with near-field coded aperture (CA) remains extremely challenging and is broadly considered unsuitable for single-photon emission computerized tomography (SPECT). This study proposes a novel CA SPECT reconstruction approach and evaluates the feasibilities of imaging and reconstructing distributed hot sources and cold lesions using near-field CA collimation and iterative image reconstruction. Computer simulations were designed to compare CA and pinhole collimations in two-dimensional radionuclide imaging. Digital phantoms were created and CA images of the phantoms were reconstructed using maximum likelihood expectation maximization (MLEM). Errors and the contrast-to-noise ratio (CNR) were calculated and image resolution was evaluated. An ex vivo rat heart with myocardial infarction was imaged using a micro-SPECT system equipped with a custom-made CA module and a commercial 5-pinhole collimator. Rat CA images were reconstructed via the three-dimensional (3-D) MLEM algorithm developed for CA SPECT with and without correction for a large projection angle, and 5-pinhole images were reconstructed using the commercial software provided by the SPECT system. Phantom images of CA were markedly improved in terms of image quality, quantitative root-mean-squared error, and CNR, as compared to pinhole images. CA and pinhole images yielded similar image resolution, while CA collimation resulted in fewer noise artifacts. CA and pinhole images of the rat heart were well reconstructed and the myocardial perfusion defects could be clearly discerned from 3-D CA and 5-pinhole SPECT images, whereas 5-pinhole SPECT images suffered from severe noise artifacts. Image contrast of CA SPECT was further improved after correction for the large projection angle used in the rat heart imaging. The computer simulations and small-animal imaging study presented herein indicate that the proposed 3-D CA SPECT imaging and reconstruction approaches worked reasonably well, demonstrating the feasibilities of achieving high sensitivity and high resolution SPECT using near-field CA collimation.

A novel three-dimensional image reconstruction method for near-field coded aperture single photon emission computerized tomography.

Coded aperture imaging for two-dimensional (2D) planar objects has been investigated extensively in the past, whereas little success has been achieved in imaging 3D objects using this technique. In this article, the authors present a novel method of 3D single photon emission computerized tomography (SPECT) reconstruction for near-field coded aperture imaging. Multiangular coded aperture projections are acquired and a stack of 2D images is reconstructed separately from each of the projections. Secondary projections are subsequently generated from the reconstructed image stacks based on the geometry of parallel-hole collimation and the variable magnification of near-field coded aperture imaging. Sinograms of cross-sectional slices of 3D objects are assembled from the secondary projections, and the ordered subset expectation and maximization algorithm is employed to reconstruct the cross-sectional image slices from the sinograms. Experiments were conducted using a customized capillary tube phantom and a micro hot rod phantom. Imaged at approximately 50 cm from the detector, hot rods in the phantom with diameters as small as 2.4 mm could be discerned in the reconstructed SPECT images. These results have demonstrated the feasibility of the authors' 3D coded aperture image reconstruction algorithm for SPECT, representing an important step in their effort to develop a high sensitivity and high resolution SPECT imaging system.

Risk factors for tracheostomy after traumatic cervical spinal cord injury.

OBJECTIVE: To determine the risk factors for the need of tracheostomy after cervical spinal cord injury (CSCI) at the acute stage. METHODS: The authors retrospectively reviewed 294 patients with acute traumatic CSCI in Xinqiao Hospital between 2012 and 2016 and analyzed the factors postulated to increase the risk for tracheostomy, including patient's age, neurological impairment scale grade and level, smoking history, combined injury, and surgical intervention. Logistic regression analysis was used to identify independent risk factor for the need of tracheostomy. RESULTS: Of 294 patients, 52 patients received tracheostomy (17.7%). The factor identified by demographics and outcomes were smoking history, cause of injury, neurological impairment scale grade and level, and combined dislocation. A multiple logistic regression model demonstrated that age of 60 years older, combined facet dislocation, C4 level high, and the American Spinal Injury Association (ASIA) A and B scale were predictive of need for tracheostomy on 95% occasions. CONCLUSION: The high age of 60 years, combined facet dislocation, C4 level high, and ASIA A and B scale are indispensable to predict the need for tracheostomy in patients with CSCI at the acute stage.

Detection of dietetically absorbed maize-derived microRNAs in pigs.

MicroRNAs are a class of small RNAs that are important in post-transcriptional gene regulation in animals and plants. These single-stranded molecules are widely distributed in organisms and influence fundamental biological processes. Interestingly, recent studies have reported that diet-derived plant miRNAs could regulate mammalian gene expression, and these studies have broadened our view of cross-kingdom communication. In the present study, we evaluated miRNA levels in cooked maize-containing chow diets, and found that plant miRNAs were resistant to the harsh cooking conditions to a certain extent. After feeding fresh maize to pigs (7 days), maize-derived miRNAs could be detected in porcine tissues and serum, and the authenticity of these plant miRNAs was confirmed by using oxidization reactions. Furthermore, in vivo and in vitro experiments demonstrated that dietary maize miRNAs could cross the gastrointestinal tract and enter the porcine bloodstream. In the porcine cells, we found that plant miRNAs are very likely to specifically target their endogenous porcine mRNAs and influence gene expression in a fashion similar to that of mammalian miRNAs. Our results indicate that maize-derived miRNAs can cross the gastrointestinal tract and present in pigs, and these exogenous miRNAs have the potential to regulate mammalian gene expression.

Aperture collimation correction and maximum-likelihood image reconstruction for near-field coded aperture imaging of single photon emission computerized tomography.

Coded aperture (CA) imaging originally developed in X-ray astronomy has not been widely used in nuclear medicine due to the decoding complexity of near-field CA images. In this paper, we present a near-field CA imaging technique and image reconstruction method for high sensitivity and high resolution single photon emission computerized tomography (SPECT). Our approach makes three contributions. First, a correction method for the aperture collimation effect is used to eliminate the near-field artifacts without dual acquisitions of mask and anti-mask images. Second, a maximum-likelihood expectation-maximization (MLEM) deconvolution method is used to restore CA images. Finally, a new MLEM-based algorithm is used to partially reconstruct three-dimensional (3-D) objects from a single projection of CA images. Experiments conducted using a dual-head SPECT system equipped with a parallel-hole collimator and a CA module show a tenfold increase in count sensitivity and significant improvement in image resolution with CA collimation as compared to parallel-hole collimation. Experiments conducted using the same dual-head SPECT system equipped with a pinhole collimator show that when the object is closer to the pinhole collimator the CA image resolution is only slightly inferior to the pinhole collimated image. We found that the MLEM deconvolution method provides an inherent nonnegativity constraint on pixel values and remarkably reduces background activities of CA images. The MLEM reconstruction algorithm for CA images is capable of reconstructing 3-D objects from a single projection and can be potentially extended to full 3-D SPECT reconstruction for CA images.

Vertebral Artery Occlusion and Recanalization After Cervical Facet Dislocation.

OBJECTIVE: To investigate clinical features of vertebral artery (VA) occlusion and recanalization after cervical facet dislocation. METHODS: During a 2-year period from January 2014 to December 2015, 29 consecutive patients with cervical facet dislocation were treated in investigator group. VA occlusion and recanalization were identified retrospectively by magnetic resonance imaging (MRI) at the time of injury and follow-up. RESULTS: VA occlusion occurred in 6 of the 29 patients (20.7%). All patients were unilateral occlusion and had no vertebrobasilar symptoms. Surgical anterior spinal fusion was performed in 5 patients, and 1 was treated by posterior fusion. Follow-up MRIs revealed VA recanalization in 5 patients. One patient did not undergo MRI because he died of respiratory failure. The time course for VA recanalization was from 6 days after injury to 4 months after operation depending on the length of VA occlusion. CONCLUSIONS: A fifth of patients with cervical facet dislocation will develop VA occlusion with rare symptomatic vertebrobasilar ischemia. VA recanalization occurs mainly within the first 4 months after injury, regardless of the length of VA occlusion.

Epidemiological features of traumatic spinal cord injury in Chongqing, China.

OBJECTIVE: To describe the epidemiological characteristics and trends of traumatic spinal cord injury in Chongqing, China. STUDY DESIGN: Hospital-based retrospective research. SETTING: Xinqiao Hospital, Chongqing. METHODS: We reviewed medical records of 554 patients with traumatic spinal cord injury (TSCI) admitted to Xinqiao Hospital from 2009 to 2013. Variables included gender, age, marital status, etiology, occupation, time of injury, level of injury, and severity of injury, the length of hospital stay, and treatment. RESULTS: The mean age of patients with TSCI was 45.6 ± 13.8 years, and the male/female ratio was 4.33:1. 94.2% (522 patients) of all patients with TSCI were married. Falls, comprising low falls and high falls (10.8% and 50.9%, respectively), were the leading reason for a hospital visit. And the second reason was MVCs (21.8%). The most common injury site was the cervical spinal cord, accounting for nearly more than 54%. The length of hospital stay ranged between 1 and 219 days (mean: 28.3 days). The proportions of complete tetraplegia, incomplete tetraplegia, complete paraplegia and incomplete paraplegia were 17.1%, 37.8%, 22.2%, and 22.9%, respectively. CONCLUSION: The result revealed that the proportion of males was higher, as well as falls and MVCs were the first two main reasons, with older mean age of patients with TSCI than other countries. The occupations with highest risk for TSCI were peasants and laborers. All of these results prompted that preventive methods should be based on the characteristics of different type of patients with TSCI.

An atlas of DNA methylomes in porcine adipose and muscle tissues.

It is evident that epigenetic factors, especially DNA methylation, have essential roles in obesity development. Here, using pig as a model, we investigate the systematic association between DNA methylation and obesity. We sample eight variant adipose and two distinct skeletal muscle tissues from three pig breeds living within comparable environments but displaying distinct fat level. We generate 1,381 Gb of sequence data from 180 methylated DNA immunoprecipitation libraries, and provide a genome-wide DNA methylation map as well as a gene expression map for adipose and muscle studies. The analysis shows global similarity and difference among breeds, sexes and anatomic locations, and identifies the differentially methylated regions. The differentially methylated regions in promoters are highly associated with obesity development via expression repression of both known obesity-related genes and novel genes. This comprehensive map provides a solid basis for exploring epigenetic mechanisms of adipose deposition and muscle growth.

Repertoire of porcine microRNAs in adult ovary and testis by deep sequencing.

BACKGROUND: MicroRNAs (miRNAs), a large family of short endogenous RNAs known to post-transcriptionally repress gene expression, participate in the regulation of almost every cellular process. Changes in miRNA expression are associated with many pathologies. Ovarian folliculogenesis and testicular spermatogenesis are complex and coordinated biological processes, in which tightly regulated expression and interaction of a multitude of genes could be regulated by these miRNAs. Identification and preliminary characterization of gonad-specific miRNAs would be a prerequisite for a thorough understanding of the role that miRNA-mediated posttranscriptional gene regulation plays in mammalian reproduction. METHOD: Here, we present the identification of a repertoire of porcine miRNAs in adult ovary and testis using deep sequencing technology. A bioinformatics pipeline was developed to distinguish authentic mature miRNA sequences from other classes of small RNAs represented in the sequencing data. RESULTS: Using this approach, we detected 582 precursor hairpins (pre-miRNAs) encoding for 732 mature miRNAs, of which 673 are unique. Statistically, 224 unique miRNAs (out of 673, 33.28%) were identified which had significant differential expression (DE) between ovary and testis libraries (P < 0.001). Most of DE miRNAs located on the X chromosome (X-linked miRNAs) (24 out of 34, 70.59%) significantly up-regulated in ovary versus testis (P < 0.001). Predictably, X-linked miRNAs are expressed in a testis-preferential or testis-specific pattern. To explore the potential for co-expression among genomic location clusters of X-linked miRNAs, we surveyed the relationship between the distance separating miRNA loci and the coordinate expression patterns of 32 high confidence X-linked miRNAs in seven normal pig tissues using the real-time quantitative PCR (q-PCR) approach. Our results show that proximal pairs of miRNAs are generally co-expressed implying that miRNAs within 50 kb of genomic bases are typically derived from a common transcript. CONCLUSIONS: The present study characterizes the miRNA transcriptome of adult porcine gonads, with an emphasis on the co-expression patterns of X-linked miRNAs. Our report should facilitate studies of the organ-specific reproductive roles of miRNAs.

A probabilistic framework based on hidden markov model for fiducial identification in image-guided radiation treatments.

Fiducial tracking is a common target tracking method widely used in image-guided procedures such as radiotherapy and radiosurgery. In this paper, we present a multifiducial identification method that incorporates context information in the process. We first convert the problem into a state sequence problem by establishing a probabilistic framework based on a hidden Markov model (HMM), where prior probability represents an individual candidate's resemblance to a fiducial; transition probability quantifies the similarity of a candidate set to the fiducials' geometrical configuration; and the Viterbi algorithm provides an efficient solution. We then discuss the problem of identifying fiducials using stereo projections, and propose a special, higher order HMM, which consists of two parallel HMMs, connected by an association measure that captures the inherent correlation between the two projections. A novel algorithm, the concurrent viterbi with association (CVA) algorithm, is introduced to efficiently identify fiducials in the two projections simultaneously. This probabilistic framework is highly flexible and provides a buffer to accommodate deformations. A simple implementation of the CVA algorithm is presented to evaluate the efficacy of the framework. Experiments were carried out using clinical images acquired during patient treatments, and several examples are presented to illustrate a variety of clinical situations. In the experiments, the algorithm demonstrated a large tracking range, computational efficiency, ease of use, and robustness that meet the requirements for clinical use.