Associations between physical activity motives and trends in moderate-to-Vigorous physical activity among adolescents over five years.

This study examined the longitudinal associations between five physical activity (PA) motives and moderate-to-vigorous PA (MVPA) across a 5-year period spanning late childhood to middle adolescence.METHODS: Data (n = 937; 55% girls; mean age = 10.33 years) were drawn from the Monitoring Activities for Teenagers to Comprehend their Habits study. PA motives and MVPA were assessed 15 times over the course of 5 years. Measurement invariance for the Motives for Physical Activity Measure-Revised (MPAM-R) questionnaire was established, and sex-stratified mixed-effects regression models were analysed.MVPA increased until a mean age of 12.18 years for girls and 12.89 years for boys before decreasing through the final assessment. From late childhood to middle adolescence, for boys, enjoyment motives were positively (ß(95% CI) = 6.14(3.86-8.43)), while fitness motives were negatively (ß(95% CI) = -4.80(-8.0, -1.59)) associated with MVPA. Whereas, for girls, competence motives were positively ß(95% CI) = 3.44(1.59-5.28)) associated with MVPABoys may benefit from PA interventions, if these were primarily aimed at increasing ones' enjoyment, whereas developing a girl's competence may provide greater contributions to a girl's future PA behaviours. PA interventions should avoid promoting the desire to be active to improve fitness, particularly among boys.

The Associations Between Clinical, Social, Financial Factors and Unmet Needs of Autistic Adults: Results from an Observational Study.

Background: Autism is a developmental disability that affects how individuals experience the world. Each Autistic individual experiences Autism in their own way, meaning that the level and type of assistance in their everyday lives vary widely. A shortage of programs and services tailored to Autistic adults exists worldwide, and the current gap between needs and services is likely to worsen as the growing number of Autistic children being diagnosed reach adulthood. This research sought to determine priorities in terms of health and social service needs of Autistic adults and to examine factors influencing whether or not these services were being received. Methods: Through a multistakeholder approach, researchers and Autistic adults codeveloped the Maritime Provinces Needs Assessment Survey and collected data from August 2017 to February 2018. The research team engaged Autistic adult partners, including one that was project colead, as full partners. We recruited survey respondents from three Maritime Provinces using mainly social media and local Autism networks. We used Poisson regression analyses to identify factors most strongly associated with the number of unmet needs reported by Autistic adults. Results: In total, 260 respondents completed the needs assessment survey: 77 self-reporting Autistic adults (aged 19-55 years), 87 Autistic adults (aged 18-63 years) whose information was provided by a proxy respondent, and 96 professionals working in the field of Autism. Autistic adults reported a mean of 2.1 ± 1.5 (self-reported) and 2.8 ± 2.1 (proxy-reported) services wanted but not received. The number of mental health and neurodevelopmental conditions, unemployment, and perception that government support is insufficient were positively related to unmet needs. Conclusions: Overall, the results of this study highlight considerable gaps among the support needs of Autistic adults. The identification of factors associated with a higher number of unmet needs helps identify potential subgroups requiring more attention. Lay summary: Why was this study done?: There is currently a shortage of programs and services for Autistic adults. Little is known about which services are most important to Autistic adults and which factors are associated with not receiving them.What was the purpose of this study?: Our goals were (1) to determine the service need priorities of Autistic adults and (2) to examine factors associated with unmet needs.What did the researchers do?: The researchers invited health professionals, service providers, policy makers, Autism advocates, as well as Autistic adults and caregivers of Autistic adults to participate as part of the project team. In the early phases of the project, we named an Autistic adult colead of the project. In doing so, we acknowledged that conducting relevant research on the Autistic adult community implies not only hearing their voices and concerns, but also providing an opportunity for equal say on the research itself.We adapted previously used surveys to align them with our objectives of focusing only on Autistic adults. We launched the survey online and promoted it using various media and community channels, many of them direct suggestions from Autistic adult team members. We made paper copies available and provided a phone number for those who needed support filling out the survey.What were the results of the study?: More than 25% of Autistic adults identified 12 different services as priority needs.Autistic adults who (1) reported more mental health and neurodevelopmental conditions, (2) perceived their mental health as poor, or (3) felt that government support was insufficient were at greater risk of having unmet needs.What do these findings add to what was already known?: Similar to previous studies, we found that the service needs of Autistic adults are varied, and that many are not receiving the services they consider a priority. Our study also went one step further by identifying factors that are associated with a higher number of unmet needs.What are potential weaknesses in the study?: Our sample does not necessarily reflect the Autistic adult community as a whole, since we were unable to guarantee that hard-to-reach segments had access to our survey. In addition, we are unable to know how our results may change over time, as our survey was filled out on one occasion only. Finally, we did not measure Autistic traits and therefore are unable to estimate how different types of traits are associated with certain needs.How will these findings help autistic adults now or in the future?: Our results may help bring attention to subgroups of Autistic adults who need more help receiving the services they require.

Mind Over Magnets - How Magnetic Particle Imaging is Changing the Way We Think About the Future of Neuroscience.

Magnetic particle imaging (MPI) is an emerging imaging technique, which has the potential to provide the sensitivity, specificity and temporal resolution necessary for novel imaging advances in neurological applications. MPI relies on the detection of superparamagnetic iron-oxide nanoparticles, which allows for visualization and quantification of iron or iron-labeled cells throughout a subject. The combination of these qualities can be used to image many neurological conditions including cancer, inflammatory processes, vascular-related issues and could even focus on cell therapies and theranostics to treat these problems. This review will provide a basic introduction to MPI, discuss the current use of this technology to image neurological conditions, and touch on future applications including the potential for clinical translation.

Complex Relationship Between Iron Oxide Nanoparticle Degradation and Signal Intensity in Magnetic Particle Imaging.

Magnetic particle imaging (MPI), using superparamagnetic nanoparticles as an imaging tracer, is touted as a quantitative biomedical imaging technology, but MPI signal properties have never been characterized for magnetic nanoparticles undergoing biodegradation. We show that MPI signal properties can increase or decrease as iron oxide nanoparticles degrade, depending on the nanoparticle formulation and nanocrystal size, and degradation rate and mechanism. Further, we show that long-term in vitro MPI experiments only roughly approximate long-term in vivo MPI signal properties. Further, we demonstrate for the first time, an environmentally sensitive MPI contrast mechanism opening the door to smart contrast paradigms in MPI.

"We are the stakeholders with the most at stake": scientific and autism community co-researchers reflect on their collaborative experience in the CONNECT project.

BACKGROUND: Little research describes the everyday challenges and needs of autistic adults. In order to fill this data gap, the CONtiNuity of carE and support for autistiC adulTs (CONNECT) project set out to learn about the health and well-being of autistic adults as well as their service and support needs. To do so, CONNECT welcomed autistic adults and caregivers of autistic adults as members of the research team, alongside researchers, policy-makers, service providers and health professionals. Autistic adults were involved in every stage of the research project and participated in team meetings held several times a year as well as in numerous email exchanges. METHODS: Two feedback questionnaires were designed for this study: one for the scientific co-researchers and one for the autism community co-researchers (the project's "patient partners"). Although the surveys varied from one another, they probed respondents to provide critical and constructive comments on issues that were central to their engagement in CONNECT. Four scientific co-researchers and four autism community co-researchers filled out the questionnaires. A comparative analysis was carried out on the responses provided to the open- and closed-ended survey questions as well as on complimentary data collected from the team's documents. RESULTS: CONNECT was seen as a positive experience for both groups. Highlights included: helping tailor and design research and its relevant materials to better suit the needs of the autistic community; establishing relationships and creating long-lasting friendships with other autistic adults; gaining a better understanding of the research process; and forging new connections with regional, national and international stakeholders. Areas for improvement include: establishing clear roles, responsibilities and expectations from the start; outlining a strategy to address unforeseen changes in project leadership; and creating a platform allowing for the involvement and participation of a more representative sample of adults on the autism spectrum. CONCLUSIONS: While not without its challenges, CONNECT demonstrates that a collaborative multi-stakeholder approach engaging autistic adults can be an effective model for conducting research on adult autism. Autistic adults and their caregivers can make the research process more open and accessible and make its outputs more relevant, useful and meaningful to the wider autistic adult community.

Magnetic Particle Imaging of Macrophages Associated with Cancer: Filling the Voids Left by Iron-Based Magnetic Resonance Imaging.

PURPOSE: Magnetic particle imaging (MPI) is an emerging molecular imaging technique that directly detects iron nanoparticles distributed in living subjects. Compared with imaging iron with magnetic resonance imaging (MRI), MPI signal can be measured to determine iron content in specific regions. In this paper, the detection of iron-labeled macrophages associated with cancer by MRI and MPI was compared. PROCEDURES: Imaging was performed on 4T1 tumor-bearing mice 16-21 days post-cancer cell implantation, 24 h after intravenous injection of Ferucarbotran, a superparamagnetic iron oxide (SPIO) or Ferumoxytol, an ultra-small SPIO. Images of living mice were acquired on a 3T clinical MRI (General Electric, n = 6) or MPI (Magnetic Insight, n = 10) system. After imaging, tumors and lungs were removed, imaged by MPI and examined by histology. RESULTS: MRI signal voids were observed within all tumors. In vivo, MPI signals were observed in the tumors of 4 of 5 mice after the administration of each contrast agent and in all excised tumors. Signal voids visualized by MRI were more apparent in tumors of mice injected with Ferumoxytol than those that received Ferucarbotran; this was consistent with iron content measured by MPI. Signal voids relating to macrophage uptake of iron were not detected in lungs by MRI, since air also appears hypointense. In vivo, MPI could not differentiate between iron in the lungs vs the high signal from iron in the liver. However, once the lungs were excised, MPI signal was detectable and quantifiable. Histologic examination confirmed iron within macrophages present in the tumors. CONCLUSIONS: MPI provides quantitative information on in vivo iron labeling of macrophages that is not attainable with MRI. The optimal iron nanoparticle for MPI in general is still under investigation; however, for MPI imaging of macrophages labeled in vivo by intravenous administration, Ferumoxytol nanoparticles were superior to Ferucarbotran.

Fluorine-19 Cellular MRI Detection of In Vivo Dendritic Cell Migration and Subsequent Induction of Tumor Antigen-Specific Immunotherapeutic Response.

PURPOSE: A major hurdle in the advancement of cell-based cancer immunotherapies is the inability to track in vivo therapeutic cell migration. With respect to dendritic cell (DC)-based cancer immunotherapies, this lack of knowledge represents an even greater hurdle as the quantity of tumor-antigen specific DC reaching a secondary lymphoid organ post injection is predictive of the magnitude of the ensuing tumor-specific immune response. We propose fluorine-19 (F-19) cellular magnetic resonance imaging (MRI) as a suitable and non-invasive imaging modality capable of detecting and quantifying DC migration in vivo and thus, serving as a surrogate marker of DC-based immunotherapeutic effectiveness. PROCEDURES: Murine DC were generated from bone marrow precursors and labeled with a [19F]perfluorocarbon ([19F]PFC)-based cell labeling agent. DC were characterized by viability and phenotyping assessments as well as characterized by ability to induce in vivo tumor-specific immune responses following immunization in a B16-F10 mouse model of melanoma. The in vivo migration of [19F]PFC (PFC)-labeled DC was first compared to control unlabeled DC by microscopy and then measured using F-19 cellular MRI. RESULTS: Culture conditions were optimized such that > 90 % of DC labeled with PFC without affecting viability, phenotype, and function. This optimization permitted consistent detection of PFC-labeled DC migration using F-19 cellular MRI and resulted in the first successful comparison of in vivo migration between PFC-labeled and control unlabeled therapeutic cells of the same origin. PFC-labeled DC are migration-competent in vivo in a B16-F10 tumor-bearing mouse model. CONCLUSIONS: We report a non-invasive and longitudinal imaging modality capable of detecting and quantifying therapeutic cell migration at both 9.4 and 3 Tesla (T) and suitable for therapeutic cell tracking in a tumor-bearing mouse model. F-19 MRI cell tracking is broadly applicable across disease states and is conducive to clinical translation.

Incidence and risk factors for anastomotic bleeding in lower gastrointestinal surgery.

OBJECTIVE: Although major anastomotic bleeding after lower gastrointestinal surgery is considered rare, it can be life-threatening if not properly managed. The objective of this study was to assess the incidence of postoperative lower gastrointestinal intraluminal bleeding and to identify its potential risk factors. This retrospective cohort study used data from charts of 314 patients who underwent digestive surgery of the colon or small intestine. Details are reported for their sociodemographic data, surgical approach, comorbidities, timing and presentation of intraluminal bleeding events, bleeding diagnosis, treatment strategies, hospital length of stay, and clinical complications. RESULTS: A total of 7 patients (2.3%) experienced intraluminal bleeding in the postoperative period. The average length of hospital stay before discharge was 12 days (median = 13 days). Patients with intraluminal bleeding had a significantly higher percentage of coronary artery diseases compared to patients without intraluminal bleeding (P value = .04), as well as having a cancer diagnosis (P value = .02). The clinical complications that were more likely in patients with intraluminal bleeding included requiring blood transfusions (P value = .01), reduction in hemoglobin (P value = .001), cardiac ischemia (P value = .02), and atrial fibrillations (P value = .02).

Parents' participation in physical activity predicts maintenance of some, but not all, types of physical activity in offspring during early adolescence: A prospective longitudinal study.

PURPOSE: We aimed to examine the longitudinal associations between parents' and youth's participation in physical activity (PA). METHODS: One hundred and ninety youth completed self-administered questionnaires 3 times per year from 2011 to 2015, and their parents completed an interviewer-administered questionnaire during a telephone interview once in 2011-2012. Data on youth's and parents' activities were classified as interdependent or coactive/independent. RESULTS: Youth with one or both parents who participated in interdependent activities were more likely to maintain participation in interdependent activities (hazard ratio (HR) = 3.63; 95% confidence interval (CI) = 1.30-10.17). Youth's sustained participation in coactive/independent activities was not associated with parents' participation in coactive/independent activities (HR = 0.97; 95%CI = 0.46-2.06). CONCLUSION: Longitudinal associations between parents' and youth's participation in PA differed across type of PA. Encouraging parents' participation in interdependent activities may promote sustained participation in interdependent activities in youth.

19F-perfluorocarbon-labeled human peripheral blood mononuclear cells can be detected in vivo using clinical MRI parameters in a therapeutic cell setting.

A 19Fluorine (19F) perfluorocarbon cell labeling agent, when employed with an appropriate cellular MRI protocol, allows for in vivo cell tracking. 19F cellular MRI can be used to non-invasively assess the location and persistence of cell-based cancer vaccines and other cell-based therapies. This study was designed to determine the feasibility of labeling and tracking peripheral blood mononuclear cells (PBMC), a heterogeneous cell population. Under GMP-compliant conditions human PBMC were labeled with a 19F-based MRI cell-labeling agent in a manner safe for autologous re-injection. Greater than 99% of PBMC labeled with the 19F cell-labeling agent without affecting functionality or affecting viability. The 19F-labeled PBMC were detected in vivo in a mouse model at the injection site and in a draining lymph node. A clinical cellular MR protocol was optimized for the detection of PBMC injected both at the surface of a porcine shank and at a depth of 1.2 cm, equivalent to depth of a human lymph node, using a dual 1H/19F dual switchable surface radio frequency coil. This study demonstrates it is feasible to label and track 19F-labeled PBMC using clinical MRI protocols. Thus, 19F cellular MRI represents a non-invasive imaging technique suitable to assess the effectiveness of cell-based cancer vaccines.

Avoidance of the vaginal incision site for mesh placement in vaginal wall prolapse surgery: A prospective study.

OBJECTIVE: To evaluate efficacy of a minimal surface area, vaginally-installed polypropylene tape (VPT), avoiding insertion on the incision line to treat an anterior, posterior or anteroposterior vaginal wall prolapse. STUDY DESIGN: Patients with an anterior, posterior or anteroposterior vaginal wall prolapse waiting for surgical treatment were included in the study. Primary outcome was the incidence of prolapse recurrence reported with combined outcome measures and was reported with Kaplan-Meier cumulative incidence. Secondary outcomes were operative complications, adverse events, urinary, colorectal and sexual functions as well as quality of life. Participation in the study involved up to 8 visits over 5 years. At each visit, patients used a self-reported questionnaire to report symptoms related to pain, urinary, colorectal, sexual functions, and quality of life. A physical examination was also performed. Paired t-tests were used to investigate change in POP-Q and quality of life measurements since baseline. RESULTS: 71 patients underwent the procedure and were followed-up for an average (standard deviation) of 32.5 (18.7) months. Only 2 (2.8%) women experienced a recurrence of their pelvic organ prolapse. Only one case of erosion and no case of persistent pain have been recorded up to 5 years post-surgery. Quality of life was improved and then sustained throughout the follow-up period (p<0.01). CONCLUSION: This VPT surgical procedure is safe and has a high level of efficacy to treat anterior, posterior or anteroposterior vaginal wall prolapse. It is also associated with improvements in quality of life of patients which are sustained for many years.

A Bit of Fit: Minimalist Intervention in Adolescents Based on a Physical Activity Tracker.

BACKGROUND: Only 5% of Canadian youth meet the recommended 60 minutes of moderate to vigorous physical activity (MVPA) per day, with leisure time being increasingly allocated to technology usage. Direct-to-consumer mHealth devices that promote physical activity, such as wrist-worn physical activity trackers, have features with potential appeal to youth. OBJECTIVE: The primary purpose of this study was to determine whether a minimalist physical activity tracker-based intervention would lead to an increase in physical activity in young adolescents. A secondary aim of this study was to assess change in physical activity across a 7-week intervention, as measured by the tracker. METHODS: Using a quasi-experimental crossover design, two groups of 23 young adolescents (aged 13-14 years) were randomly assigned to immediate intervention or delayed intervention. The intervention consisted of wearing a Fitbit-Charge-HR physical activity tracker over a 7-week period. Actical accelerometers were used to measure participants' levels of MVPA before and at the end of intervention periods for each group. Covariates such as age, sex, stage of change for physical activity behavior, and goal commitment were also measured. RESULTS: There was an increase in physical activity over the course of the study period, though it was not related to overall physical activity tracker use. An intervention response did, however, occur in a subset of participants. Specifically, exposure to the physical activity tracker was associated with an average daily increase in MVPA by more than 15 minutes (P=.01) among participants who reported being in the action and maintenance stages of behavior change in relation to participation in physical activity. Participants in the precontemplation, contemplation, and preparation stages of behavior change had no change in their level of MVPA (P=.81). CONCLUSIONS: These results suggest that physical activity trackers may elicit improved physical activity related behavior in young adolescents demonstrating a readiness to be active. Future studies should seek to investigate if integrating physical activity trackers as part of more intensive interventions leads to greater increases in physical activity across different levels of stages of behavior change and if these changes can be sustained over longer periods of time.

Quantifying tumor associated macrophages in breast cancer: a comparison of iron and fluorine-based MRI cell tracking.

Tumor associated macrophages (TAMs) are associated with tumor growth and metastasis. MRI can detect TAMs labeled with iron oxide (USPIO) or perfluorocarbon (PFC) agents. This study compared these two cell tracking approaches for imaging TAMs in vivo. 4T1 tumors were imaged with MRI at 4 days or 3 weeks post cell implantation after intravenous (i.v.) administration of either USPIO or PFC. Signal loss was detected within tumors at both time points post USPIO. Images acquired at 4 days demonstrated signal loss encompassing the entire tumor and around the periphery at 3 weeks. Number of black voxels suggested higher numbers of TAMs in the tumor at the later time point. After PFC administration, Fluorine-19 (19F) signal was detected in a similar spatial distribution as signal loss post USPIO. 19F signal quantification revealed that the number of 19F spins was not significantly different at the two time points, suggesting a similar number of TAMs were present in tumors but accumulated in different regions. 19F signal was higher centrally in tumors at 4 days and heterogenous around the periphery at 3 weeks. This study revealed that 19F-based cell tracking methods better represent TAM density and provides additional information not achievable with iron-based methods.

Application of dual 19 F and iron cellular MRI agents to track the infiltration of immune cells to the site of a rejected stem cell transplant.

PURPOSE: Cellular MRI) was used to detect implanted human mesenchymal stem cells (hMSCs) and the resulting macrophage infiltration that occurs in response to xenotransplantation. METHODS: Human mesenchymal stem cells were prelabeled with a fluorine-19 (19 F) agent prior to implantation, allowing for their visualization and quantification over time. Following implantation of 1 × 10619 F-labeled hMSCs into the mouse hind limb, longitudinal imaging was performed to monitor the stem cell graft. Macrophages were labeled in situ by the intravenous administration of an ultrasmall superparamagentic iron oxide (USPIO), allowing for tracking of the inflammatory response. RESULTS: Quantification of 19 F MRI on day 0 agreed with the implanted number of cells, and 19 F signal decreased over time. By day 14, only 22% ± 11% of the original 19 F signal remained. In a second group, USPIO were administered intravenously after implantation of 19 F-labeled hMSCs. When imaged on day 2, a significant decrease in 19 F signal was observed compared to the first group alongside a large signal void region in the corresponding proton images. Immunohistochemistry confirmed the presence of iron-labeled macrophages in the stem cell tract. CONCLUSION: A dual-labeling technique was used to noninvasively track two distinct cell populations simultaneously. This information could be used to provide additional insight into the cause of graft failure. Magn Reson Med 78:713-720, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Cellular Imaging With MRI.

Cellular magnetic resonance imaging (MRI) is an evolving field of imaging with strong translational and research potential. The ability to detect, track, and quantify cells in vivo and over time allows for studying cellular events related to disease processes and may be used as a biomarker for decisions about treatments and for monitoring responses to treatments. In this review, we discuss methods for labeling cells, various applications for cellular MRI, the existing limitations, strategies to address these shortcomings, and clinical cellular MRI.

Effects of an aerobic exercise program on driving performance in adults with cardiovascular disease.

Cardiovascular disease (CVD) has been linked to decreases in driving performance and an increased crash risk. Regular exercise has been linked to improved driving performance among healthy adults. The aim of the current study was to investigate the relationship between a 12-week cardiac rehabilitation (CR) program and driving performance among individuals with CVD. Twenty-five individuals, including 12 cardiac adults and 13 healthy adults, took part in this study. Simulated driving performance was assessed using a standardized demerit-based scoring system at 0 and 12 weeks. Cardiac participants completed a 12-week CR program between evaluations. At baseline, cardiac participants had a higher number of demerit points than healthy adults (120.9±38.1 vs. 94.7±28.3, P=0.04). At follow-up, there was an improvement in both groups' driving evaluations, but the improvement was greater among the cardiac group such that there was no longer a difference in driving performance between both groups (94.6±30 vs. 86.9±34.8, P=0.51). Participation in an aerobic exercise-based CR program appears to lead to improvements in simulated driving performances of individuals with CVD.

Tracking the fate of stem cell implants with fluorine-19 MRI.

BACKGROUND: In this study we used cellular magnetic resonance imaging (MRI) to detect mesenchymal stem cells (MSC) labeled with a Fluorine-19 (19F) agent. 19F-MRI offers unambiguous detection and in vivo quantification of labeled cells. METHODS: We investigated two common stem cell transplant mouse models: an immune competent, syngeneic transplant model and an immune compromised, xenograft transplant model. 19F labelled stem cells were implanted intramuscularly into the hindlimb of healthy mice. The transplant was then monitored for up to 17 days using 19F-MRI, after which the tissue was excised for fluorescence microscopy and immunohistochemisty. RESULTS: Immediately following transplantation, 19F-MRI quantification correlated very well with the expected cell number in both models. The 19F signal decreased over time in both models, with a more rapid decrease in the syngeneic model. By endpoint, only 2/7 syngeneic mice had any detectable 19F signal. In the xenograft model, all mice had detectable signal at endpoint. Fluorescence microscopy and immunohistochemistry were used to show that the 19F signal was related to the presence of bystander labeled macrophages, and not original MSC. CONCLUSIONS: Our results show that 19F-MRI is an excellent tool for verifying the delivery of therapeutic cells early after transplantation. However, in certain circumstances the transfer of cellular label to other bystander cells may confuse interpretation of the long-term fate of the transplanted cells.

Fluorine-19 MRI Contrast Agents for Cell Tracking and Lung Imaging.

Fluorine-19 ((19)F)-based contrast agents for magnetic resonance imaging stand to revolutionize imaging-based research and clinical trials in several fields of medical intervention. First, their use in characterizing in vivo cell behavior may help bring cellular therapy closer to clinical acceptance. Second, their use in lung imaging provides novel noninvasive interrogation of the ventilated airspaces without the need for complicated, hard-to-distribute hardware. This article reviews the current state of (19)F-based cell tracking and lung imaging using magnetic resonance imaging and describes the link between the methods across these fields and how they may mutually benefit from solutions to mutual problems encountered when imaging (19)F-containing compounds, as well as hardware and software advancements.

In vivo MR detection of fluorine-labeled human MSC using the bSSFP sequence.

Mesenchymal stem cells (MSC) are used to restore deteriorated cell environments. There is a need to specifically track these cells following transplantation in order to evaluate different methods of implantation, to follow their migration within the body, and to quantify their accumulation at the target. Cellular magnetic resonance imaging (MRI) using fluorine-based nanoemulsions is a great means to detect these transplanted cells in vivo because of the high specificity for fluorine detection and the capability for precise quantification. This technique, however, has low sensitivity, necessitating improvement in MR sequences. To counteract this issue, the balanced steady-state free precession (bSSFP) imaging sequence can be of great interest due to the high signal-to-noise ratio (SNR). Furthermore, it can be applied to obtain 3D images within short acquisition times. In this paper, bSSFP provided accurate quantification of samples of the perfluorocarbon Cell Sense-labeled cells in vitro. Cell Sense was internalized by human MSC (hMSC) without adverse alterations in cell viability or differentiation into adipocytes/osteocytes. The bSSFP sequence was applied in vivo to track and quantify the signals from both Cell Sense-labeled and iron-labeled hMSC after intramuscular implantation. The fluorine signal was observed to decrease faster and more significantly than the volume of iron-associated voids, which points to the advantage of quantifying the fluorine signal and the complexity of quantifying signal loss due to iron.

Investigating the autonomic nervous system and cognitive functions as potential mediators of an association between cardiovascular disease and driving performance.

Cardiovascular disease (CVD) impacts the autonomic nervous system and cognitive functions related to activities of daily living, including driving an automobile. Although CVD has been linked to unsafe driving, mechanisms underlying this relationship remain elusive. The aim of this study was to examine the role of cognitive functions and the autonomic nervous system as potential mediators of driving performance. Nineteen individuals having recently suffered a cardiac event and 16 individuals with no history of CVD completed a simulated drive using a STISIM simulator to assess driving performance. Heart rate was recorded throughout testing using a Polar RS800CX heart rate monitor, and measures of executive, orienting, and alerting functions were obtained through the Attention Network Test. We used the Baron and Kenny analysis method to assess potential mediating effects of the relationship between CVD and driving performance. Executive function was the only potential mediator investigated to be associated with driving (p < 0.01) and CVD (p < 0.05); however, it did not appear to play a mediating role (p = 0.28). These results suggest that individuals with CVD exhibit decrements in complex cognitive tasks such as driving and that further research is needed to better understand the mechanisms underlying this relationship.