[Protective effect and mechanism of ischemic postconditioning in rats underwent myocardial ischemia/ reperfusion injury]

OBJECTIVE

This study is designed to observe the effect of ischemic postconditioning in rats underwent acute myocardial ischemia/reperfusion injury and to investigate the related mechanism.

METHODS

A total of 30 SD rats were randomly divided into sham operation group (control group, n=10), ischemia/reperfusion group (IR group, n=10) and ischemic postconditioning group (PC group, n=10) based on random number table. Rats in IR group underwent 30 minutes myocardial ischemia by occlusion of the proximal portion of left anterior descending (LAD) coronary artery followed by 2 hours reperfusion. In control group, there was no IR intervention. In PC group, at the start of reperfusion, three cycles of 30 seconds reperfusion and 30 seconds LAD reocclusion preceded the 2 hours of reperfusion. The hemodynamic values were measured via a cannula inserted into the right common carotid artery.The area at risk was assessed by Evans blue staining and the infarct size as measured by TTC staining.Western blot and Real time PCR were respectively used to assess the expression of predicted target gene Bim and microRNA-214(miR-214) in the area at risk at the end of 2 hours reperfusion.

RESULTS

(1) The hemodynamic monitoring in different groups: the left ventricular systolic pressure (LVSP), ±dp/dtmax, and heart rate of IR group and PC group were lower than those of control group, but left ventricular end-diastolic pressure (LVEDP) was higher than that of control group (all P<0.05). The LVSP and ±dp/dtmax of PC group were higher than those of IR group, and LVEDP was lower than that of IR group (all P<0.05). (2) Myocardial ischemia area and infarction range in different groups: there was no statistically difference in the proportion of area at risk (AAR) in left ventricle (LV) (AAR/LV) between PC group and IP group ((27.00 + 7.55) % vs. (26.67 + 11.68) %, P>0.05). The proportion of infarct size in the area at risk(IS/AAR) of PC group was lower than that of IR group((30.67±3.51)% vs. (48.67±4.62)%, P<0.05). (3) The expression of Bim protein in rats ischemic myocardial tissue in different groups: the expression of Bim protein in ischemic myocardial tissue of IR group was higher than that of control group (2.34±0.15 vs. 0.75±0.05, P<0.05), and that of PC group was lower than IR group (1.25±0.14 vs. 2.34±0.15, P<0.05). (4) The expression of of miR-214 in rats ischemic myocardial tissue in different groups: the expression of miR-214 of IR group was lower than that of control group(0.20±0.04 vs. 1.00, P<0.01), and that of PC group was higer than that of IR group (0.85±0.20 vs. 0.20±0.04, P<0.01). There was no statistically difference between PC group and control group (P>0.05).

CONCLUSIONS

Postconditioning could significantly decrease the ischemia/reperfusion injury by reducing the infarct size and improve cardiac function in this in vivo rat model. The expression of Bim in postconditioning group is significantly depressed, which may play an important role in the protection process of postconditioning, and the downregulation of Bim might be mediated with the increase of miR-214 expression.

Pressure-dependent isotopic composition of iron alloys

Our current understanding of Earth's core formation is limited by the fact that this profound event is far removed from us physically and temporally. The composition of the iron metal in the core was a result of the conditions of its formation, which has important implications for our planet's geochemical evolution and physical history. We present experimental and theoretical evidence for the effect of pressure on iron isotopic composition, which we found to vary according to the alloy tested (FeO, FeH(x), or Fe3C versus pure Fe). These results suggest that hydrogen or carbon is not the major light-element component in the core. The pressure dependence of iron isotopic composition provides an independent constraint on Earth's core composition.

Distribution of pathogens causing nosocomial infection in patients with bronchial asthma

This study aimed to analyze nosocomial respiratory infection (NRI) in patients with bronchial asthma. Among the clinical data of 575 asthmatic patients that was collected and analyzed, 52 were diagnosed with NRI. The most common gram-positive bacterial species was Streptococcus pneumoniae, which was detected in 8 patients, whereas the predominant Gram-negative bacteria included Haemophilus influenzae (11 patients), Moraxella catarrhalis (8 patients), and Escherichia coli (7 patients). The simultaneous detection of all strains was predominant in patients older than 65 years of age, whereas the detection rates of S. pneumoniae, H. influenzae, E. coli, and M. catarrhalis were predominant in patients younger than 65 years old. The differences in the detection rates were not significant between the male and female groups. From this study, we can conclude that S. pneumoniae, H. influenzae, E. coli, and M. catarrhalis are common NRI-causing pathogens, and bacterial infection is the main risk factor for NRI in asthmatic patients.

Task-related differential expression of four cytochrome P450 genes in honeybee appendages

In insects, cytochrome P450 monooxygenases (P450s) contribute to phytochemical and pheromone clearance in chemoreception and xenobiotic detoxification in food processing. In eusocial species, P450 expression varies with anatomy and age-related behaviour. Adult honeybees (Apis mellifera) possess appendages differentially equipped for chemoreception; antennae and prothoracic and mesothoracic legs assess food and pheromone signals whereas metathoracic legs transport pollen over long distances. Newly eclosed bees and nurses remain in the hive and neither gather nor process food, whereas foragers collect pollen and nectar, thereby encountering phytochemicals. To understand the functions of cytochrome P450, family 4, subfamily G, polypeptide 11 (CYP4G11) in the honeybee genome, we compared its expression relative to worker age and task to expression of cytochrome P450, family 9, subfamily Q, polypeptides (CYP9Qs) known to metabolize xenobiotics. That CYP4G11 is highly expressed in forager antennae and legs, with highest expression in prothoracic and mesothoracic legs, is consistent with chemosensory perception, whereas weak expression of CYP4G11 in nurses suggests that it may process primarily exogenous rather than endogenous chemical signals. By contrast, and consistent with xenobiotic detoxification, the three CYP9Q transcripts were almost undetectable in newly eclosed workers and highest in foragers, with maximal expression in the metathoracic legs that closely contact pollen phytochemicals. These CYP4G11 expression patterns suggest a role in processing environmental signals, particularly those associated with food.

Relevance of parathyroid hormone (PTH), vitamin 25(OH)D3, calcitonin (CT), bone metabolic markers, and bone mass density (BMD) in 860 female cases

OBJECTIVE

To study the relevance of PTH, 25(OH)D3, CT, bone resorption markers C-terminal telopeptide of type I (CTX-1), and tartrate-resistant acid phosphatase (TRACP), bone formation markers bone gla protein (BGP), bone alkaline phosphatase (BALP) with the femoral neck BMD in females.

MATERIALS AND METHODS

PTH, 25(OH)D3, CT, CTX-1, TRACP, BGP, and BALP were detected by an enzyme immunoassay analyzer and femoral neck BMD were measured by a BMD detector. The results of 860 females were divided into several groups according to standard of five-year age intervals. SPSS 13.0 software was used for statistical analysis.

RESULTS

The measured values of PTH, 25(OH) D3 and CT had no differences in 35-50 age group. The measured values of 25(OH) D3 began to decline after the age of 50, and 25(OH)D3 had positive relevance with BMD. The values of CT were decreased in the age groups from 65 to 79 years old, and were significant positive correlated with BMD. The CTX-1 and TRACP had negative relevance with BMD in 35-45 age group and BGP and BALP had positive relevance with BMD in 35-45 age group. The BGP, BALP increased significantly in 50-60 age group, and CTX-1, TRACP, BGP, and BALP had negative relevance with BMD in 50-60 age group. BGP and BALP began to decline and had positive relevance with BMD after the age of 65, and CTX-1 and TRACP had negative relevance with BMD after the age of 65.

CONCLUSIONS

PTH, 25(OH)D3, CT, CTX-1, TRACP, BGP, and BALP were the important technical means for monitoring the level of bone metabolism and the diagnosis and differential diagnosis of osteoporosis.

SU-E-J-112: A Splatting Method to Generate DRRs for Deformed CT Volume

PURPOSE

To develop an efficient algorithm for generating high-quality digitally reconstructed radiographs (DRRs) for regularly and irregularly sampled volumes based on a splatting method with dynamic elliptical Gaussian kernels, and to evaluate this method using ray tracing.

METHODS

The traditional ray tracing method, which takes every intersected voxel into account, produces high quality DRRs but is very time consuming. Additionally, it is not suitable for handling irregularly-sampled volumes since it always requires image re-sampling, which leads to inaccuracy. We present a splatting approach to compute the 'footprint function', facilitating efficient perspective projection of elliptical Gaussian kernels at very low cost. This reported framework allows dealing with both regularly and irregularly sampled volumes effectively and efficiently. An XCAT digital phantom was used to generate 3D chest volumes at different respiratory phases, and CT projections are generated using ray tracing and the splatting method, respectively. Normalized cross correlation (NCC) is applied to evaluate the DRR similarity of two methods.

RESULTS

Respiratory Phases one and four are used as volume datasets from the 4D XCAT digital phantom as they represent the lung at end inhale and end exhale, respectively. The dataset of Phase one is the basic regularly-sampled volume while the dataset of Phase four is deformed from that of Phase one, and resampled to a regularly sampled dataset for the ray tracing method. NCC between splatting and ray tracing DRRs are 0.9980 and 0.9977 for Phase one and Phase four, respectively. The calculation speed of the splatting method is 3 times faster than that of ray tracing.

CONCLUSIONS

Our splatting approach can generate high-quality DRRs efficiently, and is a good alternative for current DRR generation techniques for deformed volume datasets. This research is supported by CPRIT Individual Investigator Award RP110329.

SU-E-J-127: An Initial Application of Evaluating Lung Tumor Motion Throughout Radiotherapy

PURPOSE

We present a novel method for evaluating lung tumor motion incorporating planning CT scan, imaging for patient localization, and during treatment delivery.

METHODS

Tumor motion is evaluated at three stages of the treatment process. Following the acquisition of 4D CT scans for treatment planning, tumors are contoured at one phase and registered to other phases to obtain tumor motion patterns. Tumor motion prior to each treatment is evaluated by identifying tumors directly on every raw projection of the daily localization CBCT scans. Finally, tumor motion during treatment is evaluated by analyzing MV treatment beam images. Every frame of image is evaluated as three components, each with separate DRRs: all non-moving structures, the tumor, and other moving structures. The locations of three components are determined though a registration process. In order to quantify tumor motion, the cumulated probability, the percentage of time when the tumor motion is equal to or smaller than a given range, is evaluated at every stage.

RESULTS

This methodology has been applied to five lung cancer patients undergoing radiotherapy. More than 5400 frames from MV treatment beam images and 24 CBCT scans were acquired from 12 fractions. Both the average tumor position and the cumulated probability with the range were evaluated. The tumor motion ranges are generally larger than those obtained from 4D CT. Significant variation in motion patterns was observed as well.

CONCLUSIONS

Information obtained from 4DCT is insufficient for motion assessment. In contrast, our novel methodology is capable of accurately characterizing lung tumor motion on a daily basis, without the need for implanted fiducial markers and without additional imaging dose. It provides daily verification that the tumor range is within prior estimates and covered by the treatment planning volume. This research is supported by CPRIT Individual Investigator Award RP110329.

Modeling Social Causality and Responsibility Judgment in Multi-Agent Interactions

Social causality is the inference an entity makes about the social behavior of other entities and self. Besides physical cause and effect, social causality involves reasoning about epistemic states of agents and coercive circumstances. Based on such inference, responsibility judgment is the process whereby one singles out individuals to assign responsibility, credit or blame for multi-agent activities. Social causality and responsibility judgment are a key aspect of social intelligence, and a model for them facilitates the design and development of a variety of multi-agent interactive systems. Based on psychological attribution theory, this paper presents a domain-independent computational model to automate social inference and judgment process according to an agent’s causal knowledge and observations of interaction. We conduct experimental studies to empirically validate the computational model. The experimental results show that our model predicts human judgments of social attributions and makes inferences consistent with what most people do in their judgments. Therefore, the proposed model can be generically incorporated into an intelligent system to augment its social and cognitive functionality.