Fabrication and evaluation of bilateral Helmholtz radiofrequency coil for thermo-stable breast image with reduced artifacts.

PURPOSE: The positron emission tomography (PET)-magnetic resonance (MR) system is a newly emerging technique that yields hybrid images with high-resolution anatomical and metabolic information. With PET-MR imaging, a definitive diagnosis of breast abnormalities will be possible with high spatial accuracy and images will be acquired for the optimal fusion of anatomic locations. Therefore, we propose a PET-compatible two-channel breast MR coil with minimal disturbance to image acquisition which can be used for simultaneous PET-MR imaging in patients with breast cancer. MATERIALS AND METHODS: For coil design and construction, the conductor loops of the Helmholtz coil were tuned, matched, and subdivided with nonmagnetic components. Element values were optimized with an electromagnetic field simulation. Images were acquired on a GE 600 PET-computed tomography (CT) and GE 3.0 T MR system. For this study, we used the T1-weighted image (volunteer; repetition time (TR), 694 ms; echo time (TE), 9.6 ms) and T2-weighted image (phantom; TR, 8742 ms; TE, 104 ms) with the fast spin-echo sequence. RESULTS: The results of measuring image factors with the proposed radiofrequency (RF) coil and standard conventional RF coil were as follows: signal-to-noise ratio (breast; 207.7 vs. 175.2), percent image uniformity (phantom; 89.22%-91.27% vs. 94.63%-94.77%), and Hounsfield units (phantom; -4.51 vs. 2.38). CONCLUSIONS: Our study focused on the feasibility of proposed two-channel Helmholtz loops (by minimizing metallic components and soldering) for PET-MR imaging and found the comparable image quality to the standard conventional coil. We believe our work will help significantly to improve image quality with the development of a less metallic breast MR coil.

Performance evaluation of RF coils integrated with an RF-penetrable PET insert for simultaneous PET/MRI.

PURPOSE: An "RF-penetrable" PET insert that allows the MR body coil to be used for RF transmission was developed to make it easier for an existing MR center to achieve simultaneous PET/MRI. This study focuses on experiments and analyses to study PET/RF coil configurations for simultaneous PET/MR studies. METHODS: To investigate the appropriate RF coil design, a transmit/receive (TX/RX) birdcage coil and an RX-only phased-array coil (TX from body coil), both fitting inside the PET ring were built and characterized. For MR performance evaluation, B1 field uniformity and MR image SNR were calculated. PET photon attenuation due to each coil was studied by means of CT-based attenuation maps and reconstructed PET images. RESULTS: When using the RX-only phased-array coil (TX from body coil), compared with the TX/RX birdcage coil, the B1 field uniformity and the MR image (gradient echo and fast spin echo) SNR increased by 2.4±4.8%, 386.1±62.3%, and 205.0±56.5%, respectively. Although some components of the coil were distributed within the PET FOV, no significant PET photon attenuation was shown in the CT-based attenuation map and reconstructed PET images. CONCLUSION: RF coil configurations for an RF-penetrable PET insert for simultaneous PET/MRI were studied. The RX-only phased-array coil (TX from body coil) outperformed the TX/RX birdcage coil with improved MR performance as well as negligible PET photon attenuation.

3,4-Dihydroxyflavone acts as an antioxidant and antiapoptotic agent to support bovine embryo development in vitro.

The effects of two antioxidants, superoxide dismutase (SOD) and the flavonoid 3,4-dihydroxyflavone (DHF), on bovine embryo development in vitro were examined. Blastocyst development, total cell and inner cell mass (ICM) numbers, intracellular levels of reactive oxygen species (ROS), apoptotic indices and gene expression levels were examined before and after treatment of day 2 bovine embryos (≥2-4 cells) with various concentrations of 3,4-DHF or SOD for 6 days. Statistical analysis was performed using analysis of variance, with significance defined at the P<0.05 level. SOD had no significant effect on bovine embryo development at any tested concentration (control, 32.8%; 300 U/ml, 33.9%; 600 U/ml, 24.2%). In contrast, 10 µM 3,4-DHF promoted higher blastocyst development (39.3%) than any other concentration (control, 26.7%; 1 µM, 30.3%; 50 µM, 29.5%; 100 µM, 20.5%). Compared with 300 U/ml SOD, 10 µM 3,4-DHF resulted in significantly higher blastocyst development (44.2%) (control, 31.5%; SOD 300 U/ml, 33.6%). Treatment with 3,4-DHF increased the ICM cell number and reduced intracellular ROS production and apoptotic cell numbers. When O(2) tension was decreased from 20% (high tension) to 5% (low tension), embryo development rates were doubled regardless of 3,4-DHF treatment. Under high O(2) tension, 10 µM 3,4-DHF treatment may render bovine embryo development similar to a low O(2) tension environment. The best blastocyst development was obtained under low O(2) tension plus 10 µM 3,4-DHF treatment. The relative expression levels of antioxidant (MnSOD), antiapoptotic (Survivin, Bax inhibitor) and growth-related genes (IFN-τ, Glut-5) were significantly increased after 3,4-DHF treatment, while the expression levels of oxidant (Sox) and apoptotic genes (Caspase-3 and Bax) were reduced. These results suggest that 3,4-DHF may promote the in vitro development of bovine embryos through its antioxidant and antiapoptotic effects.

Comparison of college students' behavior toward nutrition information communication between Korea and the US.

BACKGROUND/OBJECTIVES: The expansion of menu labeling to restaurants has created a need to study customers' behavior toward nutrition information. Therefore, the purpose of this research was to compare college students' behavior toward nutrition information communication between Korea and the US. This study consisted of three objectives: 1) to compare the frequency of usage as well as degree of trust regarding smartphone-based communication channels in the acquisition of nutrition information among college students between Korea and the US, 2) to compare knowledge-sharing behavior related to nutrition information among college students between Korea and the US, and 3) to identify the role of country in the process of knowledge-sharing behavior. SUBJECTS/METHODS: A survey was distributed via the web to college students in Korea and the US. Data were collected in the 2nd week of March 2017. Completed responses were collected from 423 Koreans and 280 Americans. Differences between Koreans and Americans were evaluated for statistical significance using a t-test. In order to verify the effects of knowledge self-efficacy and transactive memory capability on knowledge-sharing behavior related to nutrition information, a regression analysis was performed. RESULTS: Significant differences were found in the frequency of usage as well as degree of trust in communication channels related to nutrition information between Korean and American college students. While knowledge self-efficacy and tractive memory capability had positive effects on knowledge-sharing behavior related to nutrition information, country had a significant effect on the process. CONCLUSIONS: This study is the first to compare customer behavior toward nutrition information acquisition and sharing between Korea and the US. Comparative research on nutrition information revealed differences among the different countries. Therefore, this study contributes to the body of knowledge on the nutrition information research, in particular, by providing a comparison study between countries.

Customers' perception of the attributes of different formats of menu labeling: a comparison between Korea and the U.S.

BACKGROUND/OBJECTIVES: This study compared the perception of customers from Korea and the U.S. on the attributes of different formats of menu labeling The specific objectives were 1) to compare the customers' perceived usefulness, ease-of-understanding, clarity, and attractiveness of different formats of menu labeling between Korea and the U.S.; and 2) to compare the customers' use intention to different formats of menu labeling between Korea and the U.S. SUBJECTS/METHODS: A survey was conducted in Korea and the U.S. The participants were allocated randomly to view 1 of the 7 restaurant menus that varied according to the following types of menu labeling formats: (type 1) kcal format, (type 2) traffic-light format, (type 3) percent daily intake (%DI) format, (type 4) kcal + traffic-light format, (type 5) kcal + %DI format, (type 6) traffic-light + %DI format, and (type 7) kcal + traffic-light + %DI format. A total of 279 Koreans and 347 Americans were entered in the analysis. An independent t-test and 1-way analysis of variance were performed. RESULTS: Koreans rated type 4 format (kcal + traffic light) the highest for usefulness and attractiveness. In contrast, Americans rated type 7 (kcal + traffic light + %DI) the highest for usefulness, ease-of-understanding, attractiveness, and clarity. Significant differences were found in the customers' perceived attributes to menu labeling between Korea and the U.S. Americans perceived higher for all the 4 attributes of menu labeling than Koreans. CONCLUSIONS: The study is unique in identifying the differences in the attributes of different formats of menu labeling between Korea and the U.S. Americans rated the most complicated type of menu labeling as the highest perception for the attributes, and showed a higher use intention of menu labeling than Koreans. This study contributes to academia and industry for practicing menu labeling in different countries using different formats.

Simple, efficient, and reproducible gene transfection of mouse embryonic stem cells by magnetofection.

Embryonic stem (ES) cells are recognized as an excellent cell culture model for studying developmental mechanisms and their therapeutic modulations. The aim of this work was to define whether using magnetofection was an efficient way to manipulate stem cells genetically without adversely affecting their proliferation or self-renewal capacity. We compared our magnetofection results to those of a conservative method using FuGENE 6. Using enhanced green fluorescent protein (eGFP) as a reporter gene in D3 mouse ES (mES) cells, we found that magnetofection gave a significantly higher efficiency (45%) of gene delivery in stem cells than did the FuGENE 6 method (15%), whereas both demonstrated efficient transfection in NIH-3T3 cells (60%). Although the transfected D3 (D3-eGFP) mES cells had undergone a large number of passages (>50), a high percentage of cells retained ES markers such as Oct-4 and stage-specific embryonic antigen-1 (SSEA-1). They also retained the ability to form embryoid bodies and differentiated in vitro into cells of the three germ layers. eGFP expression was sustained during stem cell proliferation and differentiation. This is the first transfection report using magnetofection in ES cells. On the basis of our results, we conclude that magnetofection is an efficient and reliable method for the introduction of foreign DNA into mouse ES cells and may become the method of choice.

A MAPK pathway is involved in the control of cortical granule reaction and mitosis during bovine fertilization.

In order to understand the mechanism by which mitogen-activated protein kinase (MAPK) regulates fertilization, we examined the effect of the MAPK pathway inhibitor U0126 on polyspermy, cortical granule reaction and mitosis in bovine oocytes during and after fertilization. Oocytes were treated with 30 microM U0126 for 30 min prior to insemination, or from 15 to 27 hr following insemination. Western blotting with antibodies that detect active, phosphorylated MAPK revealed that MAPK activity was decreased in U0126 treated oocytes. Oocytes that were treated with U0126 before insemination displayed a significantly higher incidence of polyspermic penetration and incomplete cortical granule reaction than that observed in untreated oocytes (P < 0.05). Exposure of oocytes to 30microM U0126 15-27 hr after insemination induced aberrant microtubule assembly and cell division, often resulting in the formation of two or three daughter cells with altered shapes and sizes. These results suggest that an ERK-like cascade is part of a mechanism that controls cortical granule reaction and the formation of the mitotic spindle following sperm penetration in the bovine.

Effect of donor age on the proliferation and multipotency of canine adipose-derived mesenchymal stem cells.

Research into adipose tissue-derived mesenchymal stem cells (AD-MSCs) has demonstrated the feasibility of their use in clinical applications due to their ease of isolation and abundance in adipose tissue. We isolated AD-MSCs from young and old dogs, and the cells were subjected to sequential sub-passaging from passage 1 (P1) to P7. Canine AD-MSCs (cAD-MSCs) were examined for proliferation kinetics, expression of molecules associated with self-renewal, expression of cell surface markers, and differentiation potentials at P3. Cumulative population doubling level was significantly higher in cAD-MSCs of young donors than in those of old donors. In addition, expressions of CD73, CD80, Oct3/4, Nanog, cell survival genes and differentiation potentials were significantly higher in young donors than in old donors. The present study suggests that donor age should be considered when developing cell-based therapies for clinical application of cAD-MSCs.

Chondrogenic potential and anti-senescence effect of hypoxia on canine adipose mesenchymal stem cells.

Mesenchymal stem cells (MSCs) have the ability to differentiate into multi-lineage cells, which confers great promise for use in regenerative medicine. In this study, canine adipose MSCs (cAD-MSCs) were isolated from canine adipose tissue. These cells clearly represented stemness (Oct4, Sox2, and Nanog) and differentiation potential into the mesoderm (adipocytes, chondrocytes, and osteoblasts) at early passages. The aim of this study was to evaluate the effects of hypoxia on the differentiation potential into mesoderm, and the expression of anti-apoptotic genes associated with cell survival for the optimal culturing of MSCs. We observed that the proliferation of the cAD-MSCs meaningfully increased when cultured under hypoxic condition than in normoxic condition, during 7 consecutive passages. Also, we found that hypoxia strongly expressed anti-senescence related genes such as HDAC1 (histone deacetylase 1), DNMT1 (DNA (cytosine-5)-methyltransferase 1), Bcl-2 (inhibitor of apoptosis), TERT (telomerase reverse transcriptase), LDHA (lactate dehydrogenase A), SLC2A1 (glucose transporter), and DKC1 (telomere holoenzyme complex) and differentiation potential of cAD-MSCs into chondrocytes, than seen under the normoxic culture conditions. We also examined the multipotency of hypoxic conditioned MSCs using quantitative real-time RT-PCR. We found that the expression levels of stemness genes such as Oct-4, Nanog, and Sox-2 were increased in hypoxic condition when compared to the normoxic condition. Collectively, these results suggest that hypoxic conditions have the ability to induce proliferation of MSCs and augment their chondrogenic potential. This study suggests that cell proliferation of cAD-MSC under hypoxia could be beneficial, when considering these cells for cell therapies of canine bone diseases.

Single-cell tracking with PET using a novel trajectory reconstruction algorithm.

Virtually all biomedical applications of positron emission tomography (PET) use images to represent the distribution of a radiotracer. However, PET is increasingly used in cell tracking applications, for which the "imaging" paradigm may not be optimal. Here, we investigate an alternative approach, which consists in reconstructing the time-varying position of individual radiolabeled cells directly from PET measurements. As a proof of concept, we formulate a new algorithm for reconstructing the trajectory of one single moving cell directly from list-mode PET data. We model the trajectory as a 3-D B-spline function of the temporal variable and use nonlinear optimization to minimize the mean-square distance between the trajectory and the recorded list-mode coincidence events. Using Monte Carlo simulations (GATE), we show that this new algorithm can track a single source moving within a small-animal PET system with 3 mm accuracy provided that the activity of the cell [Bq] is greater than four times its velocity [mm/s]. The algorithm outperforms conventional ML-EM as well as the "minimum distance" method used for positron emission particle tracking (PEPT). The new method was also successfully validated using experimentally acquired PET data. In conclusion, we demonstrated the feasibility of a new method for tracking a single moving cell directly from PET list-mode data, at the whole-body level, for physiologically relevant activities and velocities.

Comparative studies on proliferation, molecular markers and differentiation potential of mesenchymal stem cells from various tissues (adipose, bone marrow, ear skin, abdominal skin, and lung) and maintenance of multipotency during serial passages in miniature pig.

Mesenchymal stem cells (MSCs) have the ability to differentiate into multi-lineage cells, which confers great promise for use in regenerative medicine. In this study, MSCs were isolated from adipose tissue, bone marrow, ear skin, lung, and abdominal skin of miniature pigs (mpMSCs), and the optimal medium (DMEM/F12-Glutamax) was selected for the culturing of mpMSCs. As a result, proliferation of the mpMSCs derived from all tissues was steadily increased when cultured with DMEM/F12-Glutamax during 14 consecutive passages. The cells harbored MSC surface markers (CD34-, CD45-, CD29+, CD44+, CD90+, and CD105+), whose levels of expression differed among the tissue sources and declined over sub-passaging. In addition, the expression of stemness markers (Oct4, Sox2, and Nanog) and differentiation into mesoderm (adipocytes, chondrocytes, and osteoblasts) were clearly represented at early passage; however, expression of stemness markers decreased, and differentiation potential was lost over sequential sub-passaging, which should be considered in the selection of mpMSC for MSC-based application.

Generation of dopaminergic neurons in vitro from human embryonic stem cells treated with neurotrophic factors.

The aim of this study was to produce dopaminergic neurons in vitro from human embryonic stem (hES) cells following treatment of various neurotrophic factors. MB03 hES cells were induced by retinoic acid (RA) or basic fibroblast growth factor (bFGF), which were further treated with brain derived neurotrophic factor (BDNF) or transforming growth factor (TGF)-alpha in each induction method during neuron differentiation days. At the final differentiation stage (21 days), all treatment groups revealed very similar levels (bFGF, 76-78%; RA, 70-74%) of mature neurons (anti-NF-200) in two induction methods irrespective of the addition of BDNF or TGF-alpha. In addition, immunostaining and HPLC analyses revealed higher levels of tyrosine hydroxylase (20+/-2.3%) and dopamine (265.5+/-62.8 pg/ml) in the bFGF- and TGF-alpha-treated hES cells than in RA- or BDNF-treated hES cells. These data are one of the first reports on the generation of dopaminergic neurons of hES cells in vitro. Also, our results indicate that TGF-alpha may be successfully used in the bFGF induction protocol and yield higher numbers of dopaminergic neurons from hES cells.

Sequential sub-passage decreases the differentiation potential of canine adipose-derived mesenchymal stem cells.

Adipose-derived mesenchymal stem cells (AD-MSCs) are abundant in adipose tissue from animals of all ages, are easily isolated, can differentiate into multi-lineage cells, and have a clinical application. This promising potential may only be achieved if the cells are expanding in a large number while maintaining their stemness in sequential passages. In this study, canine AD-MSCs (cAD-MSCs) were individually isolated from five dogs and subjected to proliferative culture with seven sub-passages. The cells at each sub-passage were characterized for properties associated with multipotent MSCs such as proliferation kinetics, expression of MSCs-specific surface markers, expression of molecules associated with self-renewal and differentiation capabilities into mesodermal lineage cells. Proliferation of the cells plateaued at passage 5 by cumulative population doubling level, while cell doubling time gradually increased with passage. MSCs surface markers (CD44, CD90, and CD105) and molecules (Oct 3/4, Sox-2, Nanog and HMGA2) associated with self-renewal were all expressed in the cells between passages 1 to 6 by RT-PCR. In addition, the cells at passage 1, 3 or 6 underwent adipogenic and chondrogenic differentiation under specific induction conditions. However, the level of adipogenic and chondrogenic differentiation was negatively correlated with the number of sub-passage. The present study suggests that sequential sub-passages affect multipotent properties of cAD-MSCs, which should be considered in their therapeutic application in regenerative medicine.

MR-based keyhole SPECT for small animal imaging.

The rationale for multi-modality imaging is to integrate the strengths of different imaging technologies while reducing the shortcomings of an individual modality. The work presented here proposes a limited-field-of-view (LFOV) SPECT reconstruction technique that can be implemented on a multi-modality MR/SPECT system that can be used to obtain simultaneous MRI and SPECT images for small animal imaging. The reason for using a combined MR/SPECT system in this work is to eliminate any possible misregistration between the two sets of images when MR images are used as a priori information for SPECT. In nuclear imaging the target area is usually smaller than the entire object; thus, focusing the detector on the LFOV results in various advantages including the use of a smaller nuclear detector (less cost), smaller reconstruction region (faster reconstruction) and higher spatial resolution when used in conjunction with pinhole collimators with magnification. The MR/SPECT system can be used to choose a region of interest (ROI) for SPECT. A priori information obtained by the full field-of-view (FOV) MRI combined with the preliminary SPECT image can be used to reduce the dimensions of the SPECT reconstruction by limiting the computation to the smaller FOV while reducing artifacts resulting from the truncated data. Since the technique is based on SPECT imaging within the LFOV it will be called the keyhole SPECT (K-SPECT) method. At first MRI images of the entire object using a larger FOV are obtained to determine the location of the ROI covering the target organ. Once the ROI is determined, the animal is moved inside the radiofrequency (rf) coil to bring the target area inside the LFOV and then simultaneous MRI and SPECT are performed. The spatial resolution of the SPECT image is improved by employing a pinhole collimator with magnification >1 by having carefully calculated acceptance angles for each pinhole to avoid multiplexing. In our design all the pinholes are focused to the center of the LFOV. K-SPECT reconstruction is accomplished by generating an adaptive weighting matrix using a priori information obtained by simultaneously acquired MR images and the radioactivity distribution obtained from the ROI region of the SPECT image that is reconstructed without any a priori input. Preliminary results using simulations with numerical phantoms show that the image resolution of the SPECT image within the LFOV is improved while minimizing artifacts arising from parts of the object outside the LFOV due to the chosen magnification and the new reconstruction technique. The root-mean-square-error (RMSE) in the out-of-field artifacts was reduced by 60% for spherical phantoms using the K-SPECT reconstruction technique and by 48.5-52.6% for the heart in the case with the MOBY phantom. The K-SPECT reconstruction technique significantly improved the spatial resolution and quantification while reducing artifacts from the contributions outside the LFOV as well as reducing the dimension of the reconstruction matrix.

Survivin protein expression in bovine follicular oocytes and their in vitro developmental competence.

This study examined the relationship between survivin expression and the stage of development of in vitro cultured bovine oocytes and embryos; and whether survivin expression is affected by the quality of cumulus-oocyte complexes (COCS) or the quality of pre-implantation embryos. A polyclonal antibody was prepared using recombinant bovine survivin protein. Expression of survivin mRNA and protein was analyzed by real-time quantitative RT-PCR and immunocytochemistry. In the first experiment, survivin mRNA expression was examined at developmental stages from germinal vesicle (GV) oocyte to blastocyst, it was significantly decreased after fertilization of matured oocytes (P<0.05), then increased slightly to the 8-cell stage followed by rapid increases at the morula and blastocyst stages (P<0.05). In the second experiment, the effect of oocyte quality on survivin protein, pro-apoptotic (bax, caspase-3) and anti-apoptotic (survivin, bax inhibitor) mRNA expression was examined. Survivin protein was more strongly expressed in good quality COCS than in poor quality COCS. The expression of the anti-apoptotic genes, survivin and bax inhibitor, was significantly higher (P<0.05) and that of the pro-apoptotic genes, bax and caspase-3, was significantly lower (P<0.05) in good compared to poor quality COCS. The developmental competence of good quality COCS (30.4% blastocysts) was significantly better than that of poor quality COCS. In the last experiment also, we confirmed that significantly higher expression of survivin and bax inhibitor genes and significantly lower expression of bax and caspase-3 genes was resulted in good quality blastocysts than in poor quality blastocysts (P<0.05). It was concluded that the expression of survivin was related to the quality of COCS, their developmental competence and the quality of in vitro produced blastocysts. Consequently, survivin may be a good candidate marker for embryo quality.

Establishment of human embryonic stem cell lines from frozen-thawed blastocysts using STO cell feeder layers.

BACKGROUND: Recently, human embryonic stem (hES) cells have become very important resources for basic research on cell replacement therapy and other medical applications. The purpose of this study was to test whether pluripotent hES cell lines could be successfully derived from frozen-thawed embryos that were destined to be discarded after 5 years in a routine human IVF-embryo transfer programme and whether an STO cell feeder layer can be used for the culture of hES cells. METHODS: Donated frozen embryos (blastocysts or pronuclear) were thawed, and recovered or in vitro developed blastocysts were immunosurgically treated. All inner cell masses were cultured continuously on an STO cell feeder layer and then presumed hES cell colonies were characterized. RESULTS: Seven and two cell lines were established from frozen-thawed blastocysts (7/20, 35.0%) and pronuclear stage embryos (2/20, 10.0%), respectively. The doubling time of hES cells on the immortal STO cell feeder layer was approximately 36 h, similar to that of cells grown using fresh mouse embryonic fibroblast (MEF) feeder conditions. Subcultured hES cell colonies showed strong positive immunostaining for alkaline phosphatase, stage-specific embryonic antigen-4 (SSEA-4) and tumour rejection antigen 1-60 (TRA1-60) cell surface markers. Also, the hES colonies retained normal karyotypes and Oct-4 expression in prolonged subculture. When in vitro differentiation of hES cells was induced by retinoic acid, three embryonic germ layer cells were identified by RT-PCR or indirect immunocytochemistry. CONCLUSIONS: This study indicates that establishment of hES cells from frozen-thawed blastocysts minimizes the ethical problem associated with the use of human embryos in research and that the STO cell feeder layer can be used for the culture of hES cells.