Synchronous recording of magnetocardiographic and electrocardiographic signals.

We present a system for simultaneous recording of the electrocardiogram and the magnetocardiogram. The measurement system contained of printed carbon electrodes and SERF magnetometer. The use of this system confirms that the position of the end of the magnetic T wave extends further than the electric T wave, which is an important indicator for the diagnosis of cardiological patients and for drug arrhythmogenicity. We analyze this phenomenon in depth, and demonstrate, that it originates from the fundamental difference between electric and magnetic measurements. The measured value is always bipolar since the electric measurements require two electrodes. We demonstrate how the dual electric and magnetic measuring system adds a new information to the commonly used electrocardiographic diagnosis. The ECG should be interpreted as the spatial asymmetry of the electric cardiac potential, and not as the potential itself. The results seem to prove, that the relation between the magnetic and the electric imaging of neural activities may be broadly applied for the benefit of medical diagnosis in cardiology and many other fields, where the neural activity is measured. This is a pilot study which requires further confirmation at the clinical level.

Dosimetric characterization of a novel UHDR megavoltage X-ray source for FLASH radiobiological experiments.

A first irradiation platform capable of delivering 10 MV X-ray beams at ultra-high dose rates (UHDR) has been developed and characterized for FLASH radiobiological research at TRIUMF. Delivery of both UHDR (FLASH mode) and low dose-rate conventional (CONV mode) irradiations was demonstrated using a common source and experimental setup. Dose rates were calculated using film dosimetry and a non-intercepting beam monitoring device; mean values for a 100 µA pulse (peak) current were nominally 82.6 and 4.40 × 10-2 Gy/s for UHDR and CONV modes, respectively. The field size for which > 40 Gy/s could be achieved exceeded 1 cm down to a depth of 4.1 cm, suitable for total lung irradiations in mouse models. The calculated delivery metrics were used to inform subsequent pre-clinical treatments. Four groups of 6 healthy male C57Bl/6J mice were treated using thoracic irradiations to target doses of either 15 or 30 Gy using both FLASH and CONV modes. Administration of UHDR X-ray irradiation to healthy mouse models was demonstrated for the first time at the clinically-relevant beam energy of 10 MV.

Measuring the outcomes of lateral ridge augmentation using cone-beam computed tomography.

OBJECTIVES: Lateral ridge augmentation (LRA) is a surgical technique to gain bone prior to implant placement. Performing cone-beam computed tomography (CBCT) pre- and post-surgery allows for quantitative comparison of the buccal-lingual width and the vertical height of the edentulous ridges. This study used CBCT images to evaluate the bone regeneration following surgery. METHODS: A total of 30 cases from adult patients who underwent LRA and had high-quality CBCT images taken pre- and post-surgery from the same CBCT scanner were available for the retrospective study. Study data included linear measurements of the bone ridge width and height obtained from the middle of the edentulous ridge and a volumetric measurement of bone growth at the edentulous site observed on the CBCT scan. RESULTS: The reliability of the measurements was excellent as indicated by Intra-Class Coefficient values of 0.974 or higher. There was a significant mean bone increase from pre-surgery compared to post-surgery for both the linear and volumetric measurements. The linear bone gain ranged from 1.5 to 2.5 mm and volumetric gain from 250 to 750 mm3 . However, two patients did not gain any bone. Multivariate regression showed the strongest predictors of bone gain post-surgery were the pre-surgery bone volume and a surgical site being in the mandible. For maxillary surgical sites, particularly anterior areas, the LRA surgeries were the least successful. CONCLUSIONS: LRA before implant placement helped to increase bone for the majority of patients, particularly for surgical sites in the mandible. The quantitative analyses in the CBCT images showed excellent intra-examiner agreement.

Exploring stressors and coping strategies among dental students during COVID-19 pandemic in British Columbia.

OBJECTIVE: The COVID-19 pandemic has caused stress among undergraduate dental students; coping mechanisms might be employed to deal with such stress. A cross-sectional study was conducted to explore the coping strategies employed by dental students at the University of British Columbia (UBC) in response to their self-perceived stressors during the pandemic. METHODS: An anonymous 35-item survey was distributed to all four cohorts of UBC undergraduate dental students enrolled in the 2021-2022 academic year, 229 students in total. The survey gathered sociodemographic information, self-perceived COVID-19-related stressor, and coping strategies via the Brief Cope Inventory. Adaptive and maladaptive coping were compared among the years of study, self-perceived stressors, sex, ethnicity, and living situations. RESULTS: Of the 229 eligible students, 182 (79.5%) responded to the survey. Of the 171 students that reported a major self-perceived stressor, 99 (57.9%) of them were stressed about clinical skill deficit due to the pandemic; fear of contraction was reported by 27 (15.8%). Acceptance, self-distraction, and positive reframing were the most used coping strategies among all students. The one-way ANOVA test revealed a significant difference in the adaptive coping scores among the four student cohorts (p = 0.001). Living alone was found to be a significant predictor for maladaptive coping (p < 0.001). CONCLUSION: The main cause of stress related to the COVID-19 pandemic for dental students at UBC is their clinical skills being negatively affected. Coping strategies including acceptance and self-distraction were identified. Continued mitigation efforts should be made to address students' mental health concerns and create a supportive learning environment.

In vivo measurements of lung function using respiratory-gated micro-computed tomography in a smoke-exposure model of chronic obstructive pulmonary disease.

Purpose: We hypothesize that in vivo respiratory-gated micro computed tomography (micro-CT) imaging can noninvasively provide structural and functional information about the lungs in a cigarette-exposure model of chronic obstructive pulmonary disease in mice. Approach: Female C57BL/6 mice were exposed to cigarette smoke or ambient air for 1, 3, or 6 months. Each mouse received a respiratory-gated micro-CT scan at baseline and another scan following the exposure period, while anaesthetized and free-breathing. Images were obtained representing end-expiration and peak inspiration, and measurements were performed to characterize the lung structure and compute functional metrics. Following the final micro-CT session, the mice were euthanized and the lungs prepared for histology. Results: Following 6 months of smoke-exposure, the mice exhibited larger increases in end-expiration lung volume and functional residual capacity, and a reduction in weight gain when compared with air-exposed mice. The histogram of CT numbers in the lung obtained during end-expiration also showed a shift to lower CT numbers following 6 months of smoke-exposure, indicating increased air content within the lungs. The metrics suggested air-trapping in the lung, which is consistent with emphysema. In the 3-month exposure group, only the reduction in weight gain was significant compared with the air-exposed group. Histological analysis confirmed that the 6-month smoke-exposed mice likely developed centrilobular emphysema as measured by the mean linear intercept. Conclusions: Respiratory-gated micro-CT imaging of free-breathing mice at multiple respiratory phases is noninvasive and provides additional information about lung structure and function that complements postmortem techniques and could be used to monitor changes over time.

In vivo micro-computed tomography imaging in liver tumor study of mice using Fenestra VC and Fenestra HDVC.

Contrast agents are used to enhance the visibility of rodent organs during in vivo micro-computed tomography imaging. Specifically, this non-invasive technique can study liver tumor growth and progression in small animals. Fenestra VC and the novel Fenestra HDVC were compared for enhancement in the liver of healthy and tumor-bearing mice, and the images were compared for their ability to define the tumor border, volume and quantity of tumors. Fenestra VC and Fenestra HDVC were injected into healthy eight-week-old female mice (C57BL/6) via the tail vein then imaged at seven different time points. The experimental results showed that 0.005 mL/g of Fenestra HDVC resulted in the same enhancement for all eight organs as 0.01 mL/g of Fenestra VC across all time points. For the tumor study, B16F10 tumors were surgically introduced into ten eight-week-old female mice (C57BL/6) then imaged in vivo over a 3 day period. Ex vivo micro-CT images of the excised livers were also obtained. The tumor volume and quantity were measured in each image, and the tumour progression observed over 3 days. We showed Fenestra HDVC is effective for in vivo imaging in rodents because the optimal enhancement level in organs is maintained at a reduced injection volume.

Measurement Accuracy in Cone Beam Computed Tomography in the Presence of Metal Artifact.

PURPOSE: Cone beam computed tomography (CBCT) image quality is known to be affected by artifacts produced by metal restorations, causing image deterioration via bright streaks and loss of gray values in the vicinity of the metallic structure. The aim of the study was to determine the impact of progressively increasing metal artifacts on the measurement accuracy of commonly evaluated points in implant treatment planning. MATERIALS AND METHODS: Holes were drilled into porcine mandibles at known distances from the alveolar crest on the buccal and lingual surfaces and filled with gutta-percha. Repeated CBCT images were taken, with progressively increasing amalgam restorations and stainless steel crowns (up to a total of eight restorations per jaw). The imaging field of view (FOV) was of a single site (5 × 5 cm2) in two different locations in the mandible, as well as a full-arch FOV (10 × 5 cm2). Images were taken using clinical settings, and with increased kVp and exposure time, without metal artifact reduction (MAR) corrections. Measurements between the buccal and lingual gutta-percha points on the mandible were performed using a digital caliper and compared to the same measurements taken digitally on the CBCT images. Measurements were obtained with no restorations (baseline) and compared with increasing number of restorations. RESULTS: Comparison between caliper measurements and baseline CBCT with no metal artifact demonstrated differences ranging from 0 to 1.7 mm, with no clear detectable pattern of change related to the restorations. Compared to baseline measurements, scans with amalgam and stainless steel restorations showed a maximum difference of 0.54 ± 0.64 mm and 0.62 ± 0.64 mm, respectively, with no significant differences with increasing metal restorations. CONCLUSION: There may be a variation of up to 1.7 mm between measured anatomical points and CBCT imaging under commonly used settings. While this result may be clinically important, it does not appear to be affected by increasing metal artifact due to amalgam restorations or stainless steel crowns. The findings of this study support current clinical practices accounting for a safety margin of up to 2 mm with any CBCT image, and not limiting CBCT scans for patients with multiple metal restorations.

Impact of advance care planning consults on advance directives completion.

OBJECTIVES: Advance care planning (ACP) consults have been credited with increasing the likelihood that patients will receive desired care at the end of life, including reduced hospitalization and spending. We aimed to investigate whether implementation of ACP consults leads to improved advance directive (AD) completion rates. STUDY DESIGN: Retrospective case-control evaluation. METHODS: Chart review was conducted among patients in hematology/oncology and primary care to compare AD completion rates of patients in each clinical area offered ACP consults between July 1, 2017, and June 30, 2018, and those not offered ACP consults prior to July 1, 2017. RESULTS: Completed ADs increased from historic rates of 1% to 65.9% of primary care patient records. Among hematology/oncology patients offered consults, completed ADs were present in 28.1% of patient records compared with historic rates of 3%. CONCLUSIONS: Patients offered ACP consults had significantly higher AD completion rates than those without consults in both primary care and hematology/oncology practices. The difference in ACP consult attendance between the primary care and hematology/oncology groups clearly suggests that further improvements can be made to assist patients in accessing AD education and completion support.

A three-dimensional virtual mouse generates synthetic training data for behavioral analysis.

We developed a three-dimensional (3D) synthetic animated mouse based on computed tomography scans that is actuated using animation and semirandom, joint-constrained movements to generate synthetic behavioral data with ground-truth label locations. Image-domain translation produced realistic synthetic videos used to train two-dimensional (2D) and 3D pose estimation models with accuracy similar to typical manual training datasets. The outputs from the 3D model-based pose estimation yielded better definition of behavioral clusters than 2D videos and may facilitate automated ethological classification.

Barriers to accepting mental health care in cancer patients with depression.

This study aimed to determine barriers to accepting mental health care among depressed cancer patients. Cancer patients who screened positive for depression were referred for mental health treatment and sent a validated questionnaire designed to assess barriers to receiving mental health care. Responses were compared between patients who accepted their referral and those who did not. Among 75 patients who agreed to participate, 51 (68%) completed the questionnaire. Reported barriers to accessing mental healthcare were not significantly different between the two groups but patients residing within 50 miles of the clinic had increased odds of attending their appointment.

Detectability of fluorescent gold nanoparticles under micro-CT and optical projection tomography imaging.

Purpose: Preclinical studies often compare micro-computed tomography (micro-CT) imaging with histology using optical microscopy of fluorescently labeled slides. However, correlating the images is difficult because the tissues appear differently in the two modalities. It would be valuable to have a single contrast medium visible on both radiographic and optical imaging. Approach: We have explored the detectability of fluorescently labeled gold nanoparticles under micro-CT and optical projection tomography (OPT) in agarose phantoms and a murine melanoma tumor model. Murine melanoma cells were used to induce tumor growth in the right hind legs of 12 C57Bl6 mice, with the maximal tumor size of 1 cm 3 . We injected Cy3 fluorescently coated gold nanorods directly into the tumors. The mice were scanned with in vivo micro-CT (for pre- and post-contrast scans). Once euthanized, the hind leg was dissected and scanned with a higher resolution specimen micro-CT and OPT. Results: The distribution of the gold nanoparticles appeared to be contained and isolated to the tumor. Alignment of micro-CT specimen scans with the OPT scans was possible, although there was also autofluorescence of the surrounding muscle tissue. Conclusions: This study highlights the potential use of fluorescently labeled gold nanoparticles for imaging murine melanoma tumors using micro-CT and OPT.

Time-course study of a gold nanoparticle contrast agent for cardiac-gated micro-CT imaging in mice.

Although micro-computed tomography (micro-CT) images have high contrast for bone or air, between soft tissues the contrast is typically low. To overcome this inherent issue, attenuating exogenous contrast agents are used to provide contrast enhancement in the vasculature and abdominal organs. The aim of this study is to measure the contrast enhancement time course for a gold nanoparticle blood-pool contrast agent and use it to perform cardiac-gated 4D micro-CT scans of the heart. Six healthy female C57BL/6 mice were anesthetized and imaged after receiving an injected dose of MVivo gold nanoparticle blood-pool contrast agent. Following the injection, we performed micro-CT scans at 0, 0.25, 0.5, 0.75, 1, 2, 4, 8, 24, 48 and 72 h. The mean CT number was measured for 7 different organs. No contrast enhancement was noticed in the bladder, kidneys or muscle during the time-course study. However, it clearly appears that the contrast enhancement is high in both right ventricle and vena cava. To perform cardiac-gated imaging, either the gold nanoparticle agent (n = 3) or an iodine-based (n = 3) contrast agent was introduced and images representing 9 phases of the cardiac cycle were obtained in 6 additional mice. A few typical cardiac parameters were measured or calculated, with similar accuracy between the gold and iodinated agents, but better visualization of structures with the gold agent. The MVivo Au contrast agent can be used for investigations of cardiac or vascular disease with a single bolus injection, with an optimal cardiac imaging window identified during the first hour after injection, demonstrating similar image quality to iodinated contrast agents and excellent measurement accuracy. Furthermore, the long-lasting contrast enhancement of up to 8 h can be very useful for scanning protocols that require longer acquisition times.

Experiences of Gender Minority Youth With the Intrauterine System.

PURPOSE: The aim of the study was to evaluate the experience of menstruating adolescents identifying as male or gender nonconforming with the levonorgestrel-releasing intrauterine system (LNG-IUS) as a method of menstrual suppression and compare to that of cisgender youth (CGY) using the LNG-IUS for noncontraceptive indications. METHODS: A retrospective chart review of gender minority youth (GMY), aged 12-22 years, who self-selected the 52 mg LNG-IUS for menstrual suppression between June 2014 and January 2018. GMY were then matched for age and time of insertion with CGY. Subjects were contacted by telephone to further explore LNG-IUS experience such as if the device was still in place, method satisfaction, current bleeding patterns, and for GMY improvement in menstrual distress. RESULTS: Thirty GMY had the LNG-IUS inserted during the study period, and 20 GMY were matched with CGY for age and time of insertion. GMY were significantly more likely to receive sedation for LNG-IUS insertion (50% vs. 15%, p = .04). Otherwise, the LNG-IUS experience was similar between groups, including mean number of telephone/office visit encounters for an LNG-IUS concern, expulsion and reinsertion rates, and need for additional medications to control bleeding. On average, the mean months of use was 14.5 ± 8.6 months in GMY and 14.6±11.5 in CGY (p = .97). LNG-IUS removal was documented in three (15%) of GMY and five (25%) of CGY. Improvement in menstrual distress was reported by 80% of GMY after the insertion of the LNG-IUS. CONCLUSIONS: Overall experience with the LNG-IUS was similar for GMY and CGY, and menstrual distress and bleeding pattern improved in the majority of GMY who self-selected this method for menstrual suppression.

Marginal Fit of Lithium Disilicate Crowns Fabricated Using Conventional and Digital Methodology: A Three-Dimensional Analysis.

PURPOSE: To compare the marginal fit of lithium disilicate (LD) crowns fabricated with digital impression and manufacturing (DD), digital impression and traditional pressed manufacturing (DP), and traditional impression and manufacturing (TP). MATERIALS AND METHODS: Tooth #15 was prepared for all-ceramic crowns on an ivorine typodont. There were 45 LD crowns fabricated using three techniques: DD, DP, and TP. Microcomputed tomography (micro-CT) was used to assess the 2D and 3D marginal fit of crowns in all three groups. The 2D vertical marginal gap (MG) measurements were done at 20 systematically selected points/crown, while the 3D measurements represented the 3D volume of the gap measured circumferentially at the crown margin. Frequencies of different marginal discrepancies were also recorded, including overextension (OE), underextension (UE), and marginal chipping. Crowns with vertical MG > 120 µm at more than five points were considered unacceptable and were rejected. The results were analyzed by one-way ANOVA with Scheffe post hoc test (α = 0.05). RESULTS: DD crowns demonstrated significantly smaller mean vertical MG (33.3 ± 19.99 µm) compared to DP (54.08 ± 32.34 µm) and TP (51.88 ± 35.34 µm) crowns. Similarly, MG volume was significantly lower in the DD group (3.32 ± 0.58 mm3 ) compared to TP group (4.16 ± 0.59 mm3 ). The mean MG volume for the DP group (3.55 ± 0.78 mm3 ) was not significantly different from the other groups. The occurrence of underextension error was higher in DP (6.25%) and TP (5.4%) than in DD (0.33%) group, while overextension was more frequent in DD (37.67%) than in TP (28.85%) and DP (18.75%) groups. Overall, 4 out of 45 crowns fabricated were deemed unacceptable based on the vertical MG measurements (three in TP group and one in DP group; all crowns in DD group were deemed acceptable). CONCLUSION: The results suggested that digital impression and CAD/CAM technology is a suitable, better alternative to traditional impression and manufacturing.

Optimization of cone beam computed tomography image quality in implant dentistry.

This study was conducted to optimize the cone beam computed tomography image quality in implant dentistry using both clinical and quantitative image quality evaluation with measurement of the radiation dose. A natural bone human skull phantom and an image quality phantom were used to evaluate the images produced after changing the exposure parameters (kVp and mA). A 10 × 5 cm2 field of view was selected for average adult. Five scans were taken with varying kVp (70-90 kVp) first at fixed 4 mA. After assessment of the scans and selecting the best kVp, nine scans were taken with 2-12 mA, and the kVp was fixed at the optimal value. A clinical assessment of the implant-related anatomical landmarks was done in random order by two blinded examiners. Quantitative image quality was assessed for noise/uniformity, artifact added value, contrast-to-noise ratio, spatial resolution, and geometrical distortion. A dosimetry index phantom and thimble ion chamber were used to measure the absorbed dose for each scan setting. The anatomical landmarks of the maxilla had good image quality at all kVp settings. To produce good quality images, the mandibular landmarks demanded higher exposure parameters than the maxillary landmarks. The quantitative image quality values were acceptable at all selected exposure settings. Changing the exposure parameters does not necessarily produce higher image quality outcomes but does affect the radiation dose to the patient. The image quality could be optimized for implant treatment planning at lower exposure settings and dose than the default settings.

Comparison of the CTDI and AAPM report No. 111 methodology in adult, adolescent, and child head phantoms for MSCT and dental CBCT scanners.

This study investigates the dosimetry methodology proposed by the American Association of Physicists in Medicine (AAPM) task group 111 and compares with the computed tomography dose index (CTDI) method and the SEDENTEXCT DI method on one clinical multislice CT and two dental cone beam CT (CBCT) scanners using adult, adolescent, and child head phantoms. Following the AAPM method, the normalized (100 mAs) equilibrium doses ([Formula: see text]) for Toshiba Aquilion One MSCT computed using dose measurements from the central hole of the phantom ([Formula: see text]), the peripheral hole of the phantom, ([Formula: see text]), and by the [Formula: see text] equation ([Formula: see text]) are in the range from 20 to 25 mGy. For i-CAT Next Generation dental CBCT, the normalized [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text] by the two SEDENTEXCT DI methods are in the range from 12 to 15 mGy. Fitting the AAPM equation is not possible for the limited scan lengths available on the CS 9300 dental CBCT. This study offers a simple CTDI-like measurement that can approximate the AAPM [Formula: see text] in clinical CBCT scanners capable of providing four or more scan lengths.

Dosimetry analysis of panoramic-imaging devices in different-sized phantoms.

The aim of this study is to measure the radiographic dose in adult, adolescent, and child head-sized PMMA phantoms for three panoramic-imaging devices: the panoramic mode on two CBCT machines (Carestream 9300 and i-CAT NG) and the Planmeca ProMax 2D. A SEDENTEXCT dose index adult phantom and custom-built adolescent and pediatric PMMA dosimetry phantoms were used. Panoramic radiographs were performed using a Planmeca ProMax 2D and the panoramic mode on a Carestream 9300 CBCT and an i-CAT NG using the protocols used clinically. Point dose measurements were performed at the center, around the periphery and on the surface of each phantom using a thimble ionization chamber. Five repeat measurements were taken at each location. For each machine, single-factor ANOVA was conducted to determine dose differences between protocols in each phantom, as well as determine the differences in absorbed dose when the same protocol was used for different-sized phantoms. For any individual phantom, using protocols with lower kVp, mA, or acquisition times resulted in statistically significant dose savings, as expected. When the same protocol was used for different-sized phantoms, the smaller phantom had a higher radiation dose due to less attenuation of x-rays by the smaller phantom and differences in the positioning of the ion chamber relative to the focal trough. The panoramic-mode on the CBCT machines produce images suitable for clinical use with similar dose levels to the stand-alone panoramic device. Significant dose savings may result by selecting age- and size- appropriate protocols for pediatric patients, but a wider range of protocols for children and adolescents may be beneficial.

A respiratory-gated micro-CT comparison of respiratory patterns in free-breathing and mechanically ventilated rats.

In this study, we aim to quantify the differences in lung metrics measured in free-breathing and mechanically ventilated rodents using respiratory-gated micro-computed tomography. Healthy male Sprague-Dawley rats were anesthetized with ketamine/xylazine and scanned with a retrospective respiratory gating protocol on a GE Locus Ultra micro-CT scanner. Each animal was scanned while free-breathing, then intubated and mechanically ventilated (MV) and rescanned with a standard ventilation protocol (56 bpm, 8 mL/kg and PEEP of 5 cm H2O) and again with a ventilation protocol that approximates the free-breathing parameters (88 bpm, 2.14 mL/kg and PEEP of 2.5 cm H2O). Images were reconstructed representing inspiration and end expiration with 0.15 mm voxel spacing. Image-based measurements of the lung lengths, airway diameters, lung volume, and air content were compared and used to calculate the functional residual capacity (FRC) and tidal volume. Images acquired during MV appeared darker in the airspaces and the airways appeared larger. Image-based measurements showed an increase in lung volume and air content during standard MV, for both respiratory phases, compared with matched MV and free-breathing. Comparisons of the functional metrics showed an increase in FRC for mechanically ventilated rats, but only the standard MV exhibited a significantly higher tidal volume than free-breathing or matched MV Although standard mechanical ventilation protocols may be useful in promoting consistent respiratory patterns, the amount of air in the lungs is higher than in free-breathing animals. Matching the respiratory patterns with the free-breathing case allowed similar lung morphology and physiology measurements while reducing the variability in the measurements.

Healthcare Barriers and Utilization Among Adolescents and Young Adults Accessing Services for Homeless and Runaway Youth.

Homeless and runaway youth are at disproportionate risk for adverse health outcomes. Many barriers to accessing healthcare have been documented; however, the relative impact of discrete barriers on homeless youth healthcare utilization behavior is not firmly established. We administered a survey examining reported barriers and healthcare utilization among adolescents and young adults accessing services at three community centers for homeless and runaway youth. Of 180 respondents, 57 % were male, 80 % non-White, and 21 % identified as a sexual minority. Stepwise logistic regression models, controlling for age and study site, explored associations between barriers and 3 healthcare utilization outcomes (doctor visit in past 12 months; regular care provider; frequent emergency department (ED) visits). The most commonly reported barriers were "don't have a ride" (27.2 %), "no insurance" (23.3 %), and "costs too much" (22.8 %). All fear-based barriers (e.g., "I don't trust the doctors") were reported by <5 % of surveyed youth. Significant predictors of having seen a doctor in the past 12 months included sexual minority status (OR 2.8, p = 0.04) and possession of health insurance (OR 4.9, p < 0.001). Female sex (OR 5.2, p < 0.001) and reported external barriers other than health insurance (OR 0.2, p < 0.001) were associated with having a regular care provider. Fear-based concerns were associated (OR 3.8, p = 0.02) with frequent ED visits, as was being insured (OR 2.2, p = 0.03). These results underscore the need to clearly define healthcare outcomes when investigating barriers to care among homeless and runaway youth as the impact of discrete barriers varies depending on outcome of focus.

Lung exposure to lipopolysaccharide causes atherosclerotic plaque destabilisation.

Epidemiological studies have implicated lung inflammation as a risk factor for acute cardiovascular events, but the underlying mechanisms linking lung injury with cardiovascular events are largely unknown.Our objective was to develop a novel murine model of acute atheromatous plaque rupture related to lung inflammation and to investigate the role of neutrophils in this process.Lipopolysaccharide (LPS; 3 mg·kg(-1)) or saline (control) was instilled directly into the lungs of male apolipoprotein E-null C57BL/6J mice following 8 weeks of a Western-type diet. 24 h later, atheromas in the right brachiocephalic trunk were assessed for stability ex vivo using high-resolution optical projection tomography and histology. 68% of LPS-exposed mice developed vulnerable plaques, characterised by intraplaque haemorrhage and thrombus, versus 12% of saline-exposed mice (p=0.0004). Plaque instability was detectable as early as 8 h post-intratracheal LPS instillation, but not with intraperitoneal instillation. Depletion of circulating neutrophils attenuated plaque rupture.We have established a novel plaque rupture model related to lung injury induced by intratracheal exposure to LPS. In this model, neutrophils play an important role in both lung inflammation and plaque rupture. This model could be useful for screening therapeutic targets to prevent acute vascular events related to lung inflammation.