Characterizing imidacloprid and metabolites in songbird blood with applications for diagnosing field exposures.

Neonicotinoids are the most widely used insecticides globally, but their rapid metabolism in vertebrates makes diagnosing wildlife exposure challenging. More detailed information on the pattern of imidacloprid metabolites over time could be used to better approximate the timing and level of exposure. Here, we applied recently developed sensitive analytical methods to measure imidacloprid (IMI) parent compound along with an expanded suite of metabolites (5-OH-IMI, IMI-olefin, desnitro-IMI, IMI-urea, 6-chloronicotinic acid, 5-AMCP, 6-OH nicotinic acid) and six other neonicotinoids in adult red-winged blackbirds (Agelaius phoeniceus) that were experimentally exposed to one of two field-realistic concentrations of imidacloprid (0.8 or 6.9 mg/kg bw). We measured concentrations in small (25 µL) plasma samples collected pre-exposure and at 1-, 6-, 24- and 48-h post-exposure. Imidacloprid was rapidly absorbed and metabolized within 48 h at both doses, with the largest decrease within 6 h post-exposure. The average proportion of parent IMI decreased from 68% of total detectable residues at 1-h to 34% at 6-h post-exposure. Two primary metabolites in blood were 5-OH-IMI and IMI-olefin, and 5-OH-IMI was the most persistent marker of exposure at 48-h. Desnitro-IMI was consistently detected following very recent (≤ 1-h) IMI exposure, and a higher ratio of parent IMI to metabolites also indicated recent exposure. Other metabolites were only detected in the higher dose group, and could be used as indicators of exposure to higher IMI concentrations. This sensitive analytical method and the observed metabolite patterns could be used to inform a growing body of field studies linking neonicotinoid exposure and effects in free-living birds.

MicroRNA-544 inhibits esophageal squamous cell carcinoma cell proliferation and enhances sensitivity to cisplatin by repressing E2F transcription factor 5.

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignancies worldwide. MicroRNA (miRNA)-544 is an important cancer-associated RNA that is downregulated in multiple types of cancer. However, the role of miR-544 in ESCC progression remains unknown. In the present study, miR-544 expression level was determined via RT-qPCR in 30 pairs of ESCC and adjacent normal tissues and in a panel of ESCC cell lines. Cell proliferation and cell apoptosis were assessed by MTT and flow cytometry assays. Luciferase reporter assay and western blot analysis were conducted to verify E2F transcription factor 5 (E2F5), an oncogene in ESCC, as a novel target gene of miR-544. The results illustrated that miR-544 is frequently downregulated in ESCC tissues and cell lines. Overexpression of miR-544 in ESCC cells resulted in decreased cell proliferation and increased cell apoptosis. Thus, E2F5 was identified as a target of miR-544, and its expression was negatively correlated with miR-544 expression in clinical ESCC tissues. More importantly, overexpression of miR-544 led to increased sensitivity of ESCC cells to cisplatin, an anticancer drug. Overall, these findings indicate that miR-544 serves as a tumor suppressor by targeting E2F5; thus, miR-544 may be a therapeutic target for the treatment of ESCC.

Computer-Aided Diagnosis (CAD) of Pulmonary Nodule of Thoracic CT Image Using Transfer Learning.

Computer-aided diagnosis (CAD) has already been widely used in medical image processing. We recently make another trial to implement convolutional neural network (CNN) on the classification of pulmonary nodules of thoracic CT images. The biggest challenge in medical image classification with the help of CNN is the difficulty of acquiring enough samples, and overfitting is a common problem when there are not enough images for training. Transfer learning has been verified as reasonable in dealing with such problems with an acceptable loss value. We use the classic LeNet-5 model to classify pulmonary nodules of thoracic CT images, including benign and malignant pulmonary nodules, and different malignancies of the malignant nodules. The CT images are obtained from Lung Image Database Consortium and Image Database Resource Initiative (LIDC-IDRI) where both pulmonary nodule scanning and nodule annotations are available. These images are labeled and stored in a medical images knowledge base (KB), which is designed and implemented in our previous work. We implement the 10-folder cross validation (CV) to testify the robustness of the classification model we trained. The result demonstrates that the transfer learning of the LeNet-5 is good for classifying pulmonary nodules of thoracic CT images, and the average values of Top-1 accuracy are 97.041% and 96.685% respectively. We believe that our work is beneficial and has potential for practical diagnosis of lung nodules.

A Novel Mathematical Model for Correcting the Physiologic Variance of Two-Dimensional Echocardiographic Measurements in Healthy Chinese Adults.

BACKGROUND: To facilitate differentiation between normal and abnormal values, it is necessary to correct echocardiographic measurements for physiologic variance induced by age, gender, and body size variables. METHODS: A total of 34 two-dimensional echocardiographic parameters were measured in 1,224 healthy Chinese adults with body mass index < 25.0 kg/m2. An optimized multivariate allometric model and scaling equations were first developed in 858 subjects (group A), and their reliability was then verified in the remaining 366 subjects (group B). The traditional single-variable isometric model in which parameters are linearly corrected by a single body size variable (height, weight, body mass index, or body surface area) was used for comparison. The success of correction was defined as the absence of significant correlations (r > 0.20, P < .05) between the corrected values and age or any body size variables, while maintaining high correlations (r > 0.80) between the corrected and uncorrected values. RESULTS: Before correction, all 34 parameters correlated significantly with one or more of the physiologic variables of age and body size and differed significantly between men and women on 29 parameters (85.3%) in both groups. The success rate of correction with the single-variable isometric model was only 11.0% (15 of 136 corrections due to four variable corrections used for each parameter), while use of the optimized multivariate allometric model successfully corrected all 34 parameters (100%) for physiologic variance induced by age and body size variables and eliminated the gender differences in 32 parameters (94.1%). A new set of reference values for corrected echocardiographic measurements independent of age, gender, and body size variables were established. CONCLUSIONS: The novel optimized multivariate allometric model developed in this study is superior to traditional the single-variable isometric model in the correction of echocardiographic parameters for physiologic effects of age, gender, and body size variables and thus should be encouraged in both scientific research and clinical practice.

Part-per-trillion LC-MS/MS determination of neonicotinoids in small volumes of songbird plasma.

Neonicotinoids are the most widely used class of insecticides in the world, and there are increasing concerns about their effects on non-target organisms. Analytical methods to diagnose exposure to neonicotinoids in wildlife are still very limited, particularly for small animals such as songbirds. Blood can be used as a non-lethal sampling matrix, but the sample volume is limited by body size. Neonicotinoids have a low bioaccumulation potential and are rapidly metabolized, therefore, sensitive assays are critically needed to reliably detect their residues in blood samples. We developed an efficient LC-MS/MS method at a part-per-trillion (pg/ml) level to measure eight neonicotinoid related insecticides (acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitenpyram, thiacloprid and thiamethoxam) plus one metabolite (6-chloronicotinic acid) in small volumes (50 µL) of avian plasma. The average recovery of target compounds ranged from 95.7 to 101.3%, and relative standard deviations were between 0.82 and 2.13%. We applied the method to screen blood samples from 36 seed-eating songbirds (white-crowned sparrows; Zonotrichia leucophrys) at capture, and detected imidacloprid in 78% (28 of 36), thiamethoxam in 22% (8 of 36), thiacloprid in 11% (4 of 36), and acetamiprid in 11% (4 of 36) of wild-caught sparrows. 6 h after capture, birds were orally dosed with 0 (control), 1.2 or 3.9 mg of imidacloprid/kg bw, test results using this method indicated that plasma imidacloprid was significantly elevated (low 26-times, high 316-times) in exposed groups. This is the first study to confirm neonicotinoid exposure in small free-living songbirds through non-lethal blood sampling, and to demonstrate that environmentally realistic doses significantly elevate circulating imidacloprid concentrations. This sensitive method could be applied to characterize exposure to neonicotinoids in free-living wildlife and in toxicological studies.

Ultra-trace level speciated isotope dilution measurement of Cr(VI) using ion chromatography tandem mass spectrometry in environmental waters.

The reliable analysis of highly toxic hexavalent chromium, Cr(VI), at ultra-trace levels remains challenging, given its easy conversion to non-toxic trivalent chromium. This work demonstrates a novel analytical method to quantify Cr(VI) at low ngL(-1) concentration levels in environmental water samples by using speciated isotope dilution (SID) analysis and double-spiking with Cr(III) and Cr(VI) enriched for different isotopes. Ion chromatography tandem mass spectrometry (IC-MS/MS) was used for the analysis of Cr(VI) as HCrO4(-) → CrO3(-). Whereas the classical linear multipoint calibration (MPC) curve approach obtained a method detection limit (MDL) of 7ngL(-1) Cr(VI), the modified SID-MS method adapted from U. S. EPA 6800 allowed for the quantification of Cr(VI) with an MDL of 2ngL(-1) and provided results corrected for Cr(VI) loss occurred after sample collection. The adapted SID-MS approach proved to yield more accurate and precise results than the MPC method, allowed for compensation of Cr(VI) reduction during sample transportation and storage while eliminating the need for frequent external calibration. The developed method is a complementary tool to routinely used inductively-coupled plasma (ICP) MS and circumvents typically experienced interferences.

Limited view reconstruction for differential phase-contrast computed tomography.

This paper describes an algebraic reconstruction algorithm that uses total variation (TV) regularization for differential phase contrast computed tomography (DPC-CT) using a limited number of views. In order to overcome over-flattening inherent in TV regularization, a two-step reconstruction process is used: we first reconstruct tomographic images of gradient refractive index from differential projections with TV regularization; these images are then used to compute tomographic images of refractive index by solving the Poisson equation. We incorporate TV regularization in the reconstruction process because the distribution of gradient refractive index is much more flattened than the refractive index. Simulations of the proposed method demonstrate that it can achieve satisfactory image quality from a much smaller number of projections than is required by the Nyquist sampling theorem. We experimentally prove the feasibility of the proposed method using dark field imaging optics at PF-14C beamline at the Photon Factory, KEK. The differential phase contrast projection data was experimentally acquired from a biological sample and DPC-CT images were reconstructed. We show that far fewer projections are needed when the proposed algorithm is used.

A 800 kV compact peaking capacitor for nanosecond generator.

An extremely compact high voltage peaking capacitor is developed. The capacitor has a pancake structure with a diameter of 315 mm, a thickness of 59 mm, and a mass of 6.1 kg. The novel structural design endows the capacitor with a better mechanical stability and reliability under hundreds of kilovolts pulse voltage and an inner gas pressure of more than 1.5 MPa. The theoretical value of the capacitor self-inductance is near to 17 nH. Proved by series of electrical experiments, the capacitor can endure a high-voltage pulse with a rise time of about 20 ns, a half-width duration of around 25 ns, and an amplitude of up to 800 kV in a single shot model. When the capacitor was used in an electromagnetic pulse simulator as a peaking capacitor, the rise time of the voltage pulse can be reduced from 20 ns to less than 3 ns. The practical value of the capacitor's inductance deduced from the experimental date is no more than 25 nH.

Region of interest tracking in real-time myocardial contrast echocardiography.

The real-time myocardial contrast echocardiography (RT MCE) is a new echocardiography technology, which allows clinicians to noninvasively evaluate the perfusion of myocardial capillary of patients, using the quantitative analysis of RT MCE. But the accurate analysis requires tracking the position of region of interest (ROI) within the myocardial area, so as to compensate for the translation or rotation offsets, which are due to such uncontrollable factors as heart motion. We used diamond search method and Brox's coarse-to-fine warping optical flow technique for this ROI tracking problem. We validated our methods by comparing the quantitative analysis results of RT MCE using our methods with those using Lucas & Kanade's optical flow technique, which had been report to be accurate enough for this ROI tracking. We finally present some examples of animal experiment to show the effectiveness and the clinical application value of our ROI tracking methods.

Feature-space-based FMRI analysis using the optimal linear transformation.

The optimal linear transformation (OLT), an image analysis technique of feature space, was first presented in the field of MRI. This paper proposes a method of extending OLT from MRI to functional MRI (fMRI) to improve the activation-detection performance over conventional approaches of fMRI analysis. In this method, first, ideal hemodynamic response time series for different stimuli were generated by convolving the theoretical hemodynamic response model with the stimulus timing. Second, constructing hypothetical signature vectors for different activity patterns of interest by virtue of the ideal hemodynamic responses, OLT was used to extract features of fMRI data. The resultant feature space had particular geometric clustering properties. It was then classified into different groups, each pertaining to an activity pattern of interest; the applied signature vector for each group was obtained by averaging. Third, using the applied signature vectors, OLT was applied again to generate fMRI composite images with high SNRs for the desired activity patterns. Simulations and a blocked fMRI experiment were employed for the method to be verified and compared with the general linear model (GLM)-based analysis. The simulation studies and the experimental results indicated the superiority of the proposed method over the GLM-based analysis in detecting brain activities.

Numerical methods and workstation for the quantitative analysis of real-time myocardial contrast echocardiography.

Using the quantitative analysis of real-time myocardial contrast echocardiography (RT MCE), clinicians can assess the myocardial perfusion of patients, noninvasively and accurately. We designed a workstation to assist clinicians to automatically implement the accurate analysis of RT MCE. The workstation can compute some hemodynamic parameters of myocardial microcirculation, e.g., myocardial blood flow, myocardial blood flow mean velocity, and myocardial blood volume. Our new methods involved in the quantitative analysis of RT MCE are summarized as follows. 1) A novel orthogonal array optimization (OAO) technique was proposed and used to estimate the unknown parameters of the nonlinear model to guarantee numerical stability. 2) Brox's coarse-to-fine warping optical flow technique was employed to automatically track the region of interest located inside the myocardial area to ensure the accuracy of the quantitative analysis. Finally, we illustrate some examples of clinical studies to indicate the effectiveness of the system and the reliability of the methods.

The optimal linear transformation-based fMRI feature space analysis.

This paper proposes a method of extending the optimal linear transformation (OLT), an image analysis technique of feature space, from magnetic resonance imaging (MRI) to functional magnetic resonance imaging (fMRI) so as to improve the activation detection performance over conventional approaches of fMRI analysis. The method was: (1) ideal hemodynamic responses for different stimuli were generated by convolving the theoretical hemodynamic response model with the stimulus timing, (2) considering the ideal hemodynamic responses as hypothetical signature vectors for different activity patterns of interest, OLT was used to extract the features of fMRI data. The resultant feature space had particular geometric clustering properties. It was then classified into different groups, each pertaining to an activity pattern of interest; the applied signature vector for each group was obtained by averaging, (3) using the applied signature vectors, OLT was applied again to generate fMRI composite images with high SNRs for the desired activity patterns. Simulations and a blocked fMRI experiment were employed to validate the proposed method. The simulation and the experiment results indicated the proposed method was capable of improving some conventional methods to be more sensitive to activations, having strong contrast between activations and inactivations, and being more valid for complex activity patterns.

[Generation of a P19-alphaMHC-EGFP reporter line and cardiomyocyte differentiation].

OBJECTIVE: To generate a P19-alphaMHC-EGFP reporter line and induce cardiomyocyte differentiation of this reporter line. METHODS: The P19 cells were transfected with palphaMHC-EGFP, a P19-alphaMHC-EGFP reporter line was obtained after G418 selection and limited dilution of recombinant clones. The reporter line was induced to differentiate into cardiomyocytes which would beat and express green fluorescent protein. A comparison of cardiomyocyte differentiation rate and cTnI expression amount between the reporter line and the untransfected P19 cells was also performed. The ultrastructure was observed under transmission electron microscope. RESULTS: The ultrastructure characteristics indicated cardiomyocytes-like changes on induction day 10. The beating cardiomyocytes which express GFP appear in the seventh induction day. The cardiomyocyte differentiation rate and cTnI expression amount of P19-alphaMHC-EGFP reporter line were similar as those in untransfected P19 cells (P > 0.05). CONCLUSION: The P19-alphaMHC-EGFP reporter line is of great benefit for identifying and purifying cardiomyocytes from undifferentiated P19 cells without influencing the differentiation of P19 cells. This feature makes P19-alphaMHC-EGFP reporter line a promising cell source for clinical cardiomyocyte replacement therapy.

[Development of a new MCE-based quantitative analysis system for myocardial microcirculation].

In this paper is presented the research and development of a new myocardial contrast echocardiography (MCE)-based quantitative analysis system for myocardial microcirculation. The system can measure the values of A, beta, A x beta, A-EER (endo-epi ratio of A), beta-EER and A x beta-EER from the signal intensity of real-time 2-D grayscale images and power Doppler images; it can draw the time-intensity curves to indicate the variation of the intensity of microbubbles scattering in subendocardial layer and subepicardial layer with the varying of myocardial segments; and it can estimate the hemodynamic parameters by nonlinear regression analysis. So the MCE software system has brought the quantitative analysis of real-time MCE to success.

Characterization and virulence retention of viable but nonculturable Vibrio harveyi.

Vibrio harveyi has been reported to enter into a viable but nonculturable (VBNC) state. Two clinical V. harveyi strains, SF1 and CW2, and the type strain, VIB295(T), were incubated in sterilized seawater at 4 degrees C. Plate counts in these strains declined to undetectable levels (<0.1 CFU mL(-1)) within 69, 67 and 65 days, respectively. The direct viable count (DVC) declined from 10(6) to 10(4) active cells mL(-1) and remained constant at this level by a DVC. VBNC cell numbers could be restored via a temperature upshift when grown in yeast extract with the addition of Tween 20 or compound vitamin B. Reverse transcriptase-PCR was used to monitor virulence gene expression within VBNC cells. No expression of the hemolysin gene was detected in VBNC cells. VBNC and resuscitative cells were intraperitoneally injected into zebra fish separately. No death was observed in the groups inoculated with VBNC cells. The fish inoculated with the resuscitative cells died within 7 days, the lethal dose 50% (LD(50)) being 2.85 x 10(4) CFU mL(-1), a value similar to that for groups inoculated with normal cells (2.28 x 10(4) CFU mL(-1)). This suggested that VBNC V. harveyi might retain pathogenic potential.

Quantification of transmural gradient of blood flow in myocardial ischemia with real-time myocardial contrast echocardiography and dipyridamole stress test.

Transmural redistribution of myocardial blood flow (MBF) is the earliest sign of myocardial ischemia. We aimed to evaluate the ability of real-time myocardial contrast echocardiography (MCE) combined with dipyridamole stress to quantify the transmural gradient of MBF during graded coronary stenosis. Real-time MCE was performed in 14 open-chest dogs at seven experimental stages: baseline; hyperemia induced by 6-min infusion of dipyridamole; 50%, 75% and 90% reduction of hyperemic flow after constriction in each stage for 10 min; reperfusion for 10 min; and subtotal occlusion of the left anterior descending coronary artery (LAD) for 90 min. We obtained MCE perfusion parameters from subendocardial (A-endo, beta-endo and A x beta-endo) and subepicardial (A-epi, beta-epi and A x beta-epi) layers of the ventricular septum and calculated their transmural gradients (A-EER, beta-EER and A x beta-EER) and systolic wall thickening (SWT). The sensitivity and specificity of each parameter for predicting 75% reduction of hyperemic flow, which was defined as mild myocardial ischemia, were derived by receiver operating characteristic (ROC) curve analysis. No transmural gradients were found at baseline; during maximal hyperemia and 50% reduction of hyperemic flow. beta-endo, A x beta-endo, beta-EER and A x beta-EER decreased significantly when the hyperemic flow was reduced by 75% or more. In contrast, SWT remained unchanged until the hyperemic flow was reduced by 90%. Among all parameters measured, beta-EER and A x beta-EER had the highest and SWT the lowest sensitivity and specificity in predicting mild myocardial ischemia. In conclusion, real-time MCE combined with dipyridamole stress allows for quantification of the transmural gradient of MBF. beta-EER and A x beta-EER are more sensitive than SWT and other MCE parameters in detecting mild myocardial ischemia.

Cardiomyocyte apoptosis in the right auricle of patients with ostium secundum atrial septal defect diseases.

Ostium secundum atrial septal defect (osASD) is one of the most commonly occurring cardiac malformations. Although some embryological pathways have been elucidated, the molecular etiologies of ASD are not fully understood. Previous microarray analysis in our laboratory identified differentially expressed genes between osASD and normal right auricular myocardium. Of the 1056 differentially expressed genes, 14 genes were related to apoptosis: eight pro-apoptotic genes were up-regulated and six anti-apoptotic genes were down-regulated in ASD patients. In the current study, we utilized semi-quantitative RT-PCR, electron microscopy, TUNEL and flow cytometry to further understand the role of apoptosis in the atrium of osASD patients. RT-PCR results confirmed differential expression data from previous microarray studies. Additionally, while apoptosis was detected in the right auricular myocardium of all osASD patients, it was absent in controls. These data suggested apoptosis may play an important role in the pathogenesis of osASD or possibly occurs as a consequence of volume overload and hemodynamic changes in right atrium of osASD patients.

[The three-dimension medical image reconstruction simulation on 3D Shepp-Logan head phantom].

Shepp-Logan head phantom is the classical model of simulation computing in Computerized Tomography. This paper proposes a new method--considering 3D Shepp-Logan head phantom as the basic reference model to carry on simulation experiment and algorithms performance evaluating in three-dimension medical image reconstruction field. The paper introduces the design and the implementation of 3D Shepp-Logan head phantom as well the computing of projection data at first, and then describes the simulation process of the three-dimension medical image. The numerical experiment gives the three-dimension medical image reconstruction simulations based on 3D Shepp- Logan head phantom. The result of this experiment indicates the accuracy of model computing and the feasibility of our this method.

[Design of a quantitative analysis software system for myocardial contrast echocardiography].

This article reports a quantitative analysis software system for myocardial contrast echocardiography (MCE). It can measure the signal intensity of grayscale images and power Doppler images, draw the time-intensity curves of variations on the intensity of microbubbles scattering in subendocardial layer and subepicardial layer with the pulsing intervals, and estimate the hemodynamic parameters by nonlinear regression analysis. This system has been applied to a study on 20 healthy volunteers, and the results suggest that the software has the capacity for bringing the quantitative analysis of MCE to success. The MCE software system conforms to the DICOM standard and can be integrated into PACS.