Objective To assess longitudinal segmental myocardial strain(?),displacement(D) and the changes of the inner dimension of left ventricle(?L),and to establish their spatial correlationship during cardiac pacing and conductive block.Methods The standard apical four chamber view of left ventricle were acquired during cardiac pacing(n=12),right bundle branch block(RBBB,n=13) and sinus rhythm(n=14) using GE Vivid 7 dimension and the M3S probe with(4.0) MHz for the analysis of the longitudinal myocardial segmental(apical and basal segments) ? and D of left ventricle with two dimensional strain analysis software.The maximal and change longitudinal dimension of left ventricle was measured and calculated at end-diastole and end-systole respectively.The differences of the above parameters were compared and the spatial correlationships among them were analyzed.Results The peak ? of the septal basal segment during cardiac pacing was significant higher than that of the apical segment.There were significant differences in the peak D and(?D)(D_(basal)-D_(apical)) at lateral wall among sinus rhythm,RBBB and pacing group(P

Objective To evaluate the mechanical homogeneity pattern of isolated carotid atherosclerotic plaque intima on longitudinal axis view using ultrasonic velocity vector imaging.Methods Fourty six patients with 48 isolated plaques were undergone the high frequency ultrasound scanning,the real-time two-dimensional longitudinal-axis gray scale view at the maximal thickness of the plaque was obtained in three complete cardiac cycles.A dedicated velocity vector imaging(ⅤⅤⅠ)workstation was used for the off-line dynamic two-dimensional gray-scale image analysis and mechanics parameter(i.e.,the peak strain and the absolute difference of the peak strain)assessment at the sites of the upper,middle and down stream separately.The length and direction distribution of the velocity vectors at the carotid atherosclerotic plaque intima were observed.Wilcoxon test was utilized for the comparison of the peak strain and the absolute difference of the peak strain between two sites.Results The chaos phenomenon of velocity vector distribution at the sites of plaque intima occurred significantly differed from those uniform velocity vectors at the reference sites.According to the two groups of the higher strain value side and the lower strain value side on the upper stream and the down stream of the plaque intima,the peak strain at the higher strain value side was significantly higher than the lower strain value side(P=0.000).There was a significantly difference between the absolute difference of peak strain from the higher strain value side to the middle stream point of the plaque intima and the absolute difference of peak strain from the lower strain value side to the higher strain value side of the plaque intima(P＜0.017).Conclusions The length and direction distribution of velocity vectors of the isolated carotid atherosclerotic plaque intima on longitudinal axis view are uneven,the mechanical heterogeneity pattern exists at the plaque intima and could be visualized and quantitatively evaluated using ultrasonic velocity vector imaging.

Objective To establish a reverse transcription nested polymerase chain reaction ( RT-nPCR ) assay for detection of tree shrews orthoreovirus (TRV).Methods Three strains of TRV were respectively isolated from fresh feces of three tree shrews that came from the same field at different times .We designed and synthesized two pairs of MRV L1 gene nested primers and established the system of RT-nPCR.The TRV RNA was extracted and reversely transcribed to cDNA as a template for nested-PCR amplification.The developed RT-nPCR was optimized.The specificity and sensitivity were tested.Finally, the RT-nPCR was used to detect TRV in 25 tree shrew samples.Results Taking the genomic RNA of TRV as template, the RT-nPCR was able to amplify a specific fragment band targeting the L 1 gene, while there were no target bands in the normal cell control , ( Wa strain rotavirus , hepatitis A virus , and herpes simplex virus ) .The RNA of TRV was diluted by 1:10 to 1:109 .Each dilution sample was analyzed by the RT-nPCR.The minimum detectable concentration of RNA was 0.01 pg/μL.The results of RT-nPCR detection showed that 4 of the 15 tree shrews were TRV-positive in the survival group , and 10 of 10 tree shrews were TRV-positive in the death group . Conclusions The RT-nRCR assay established in this study is accurate , specific and sensitive .Therefore, it can be used for routine detection of TRV in quality assurance testing .

Objective To understand the histological characteristics of the major endocrine organs of tree shrew , and provide a normal histological atlas of endocrine organs of tree shrew .Methods Ten artificially fed healthy tree shrews were killed and dissected after anesthesia .The thyroid, parathyroid, adrenal and pituitary glands were observed by gross inspection and samples were taken for routine histological examination with HE staining .Results ( 1 ) The thyroid gland was pale yellow, located on both sides of the 2-4 tracheal rings.The thyroid gland was plate-shaped, its surface was covered with a thin fibrous capsule . The thyroid parenchyma was divided into several lobules by stretched capsule membrane .Follicular and parafollicular cells were distributed in the lobules , and red colloid was present in follicular cavity.(2) Each side had one parathyroid , located on the cranial or the outer surface of the middle part of the thyroid gland, and was slightly covered by thyroid .The gland was round or oval , and its parenchyma was made up of the principal cells and eosinophil cells , and acinar structure appeared in the parenchyma .( 3 ) The adrenal glands were oval , yellow color, located in the renal hili , and linked to the kidneys .They were surrounded by a thin capsule .The parenchyma was divided into cortex and medulla .The cortex was divided into zona glomerulosa , zona fasciculata and zona reticularis from outside to inside.The zona glomerulosa was the thickest layer and the zona fasciculata was the thinnest .The medulla cells formed clumps or mesh, with central vein in the central part .(4) The pituitary gland was located in the sella turcica , with no recessus hypophysis .The pituitary gland was composed of the adenohypophysis and neurohypophysis .Its surface was covered with a connective tissue capsule .The pituitary gland was divided into distal part , middle part and pars tuberalis . neurohypophysis was made up of neural and pars infundibularis .Conclusions The histological atlas of endocrine organs in the tree shrew is established , which is close to that of the primate animals in the morphology , and provide histological evidence for the study of tree shrew endocrine organs and disorders , as well as the animal model of human diseases .

Tree shrews get more and more concerns due to many of its physiological , biochemical and anatomical characteristics similar to those of human beings .Therefore, tree shrews models of human diseases such as viral diseases , neurological diseases and tumors attract more and more attention of researchers .In this article we will review the recent ad-vances in application of tree shrew models in research on human viral diseases .

With introduction of current main methods for heart fluid mechanics researches, we studied the characteristics and weakness for three primary analysis methods based on magnetic resonance imaging, color Doppler ultrasound and grayscale ultrasound image, respectively. It is pointed out that particle image velocity (PIV), speckle tracking and block match have the same nature, and three algorithms all adopt block correlation. The further analysis shows that, with the development of information technology and sensor, the research for cardiac function and fluid mechanics will focus on energy transfer process of heart fluid, characteristics of Chamber wall related to blood fluid and Fluid-structure interaction in the future heart fluid mechanics fields.
Algorithms ; Biomechanical Phenomena ; Heart ; physiology ; Humans ; Image Interpretation, Computer-Assisted ; Magnetic Resonance Imaging ; Ultrasonography, Doppler

Objective To evaluate the changes of left ventricular(LV) 3-dimension peak displacement (3D-D) during different cardiac pacing patterns. To provide a reliable mechanical data base for the optimization cardiac pacing. Methods Cardiac pacings in open-chest Beagle canine models( n = 10) were performed using three patterns[I, e. , right ventricular apical pacing (RVA-P), LV lateral pacing (LVL-P)and LV apical pacing(LVA-P)],3D full volumetric real-time imaging were acquired in a completed cardiac cycle. The 3D-D,3D-D peak time (3D-DTc) and the standard deviation of TC(3D-DTSD) were calculated and analyzed in different pacing patterns for difference and spatial correlationship. Results ① The 3D-D of LVL-P and LVA-P state decreased compared with BASE and RVA-P state, there were significant 3D-D difference of mid anterior,mid anteriorspetal, mid interior,mid posterior, mid lateral between LVL-P and BASE, RVA-P patterns( P ＜0.05). There were significant 3D-D difference of mid anterior,mid lateral,mid posterior between LVA-P and RVA-P patterns groups( P ＜0.05). There were significant 3D-D difference of all segments in apical level between LVL-P,LVA-P and BASE, RVA-P states( P ＜0.05). ② Corrected by the heart rate,the 3D-DTC of different cardiac pacing patterns were shorter than BASE state. ③ There were no significant 3D-DTSD difference between different cardiac pacings and BASE patterns. There were significant 3D-DTSD difference between RVA-P and LVA-P patterns (P ＜ 0.05). Conclusions LV mechanical activation and synchronization could be maintained during RVA-P rather than LVA-P and LVL-P. Echocardiographic study of left ventricular 3D-D can actually reveal myocardial mechanical state during different cardiac pacings and BASE patterns.