Nonuniform sliding-window reconstruction for accelerated dual contrast agent quantification with MR fingerprinting

OBJECTIVE

MR fingerprinting (MRF) can enable preclinical studies of cell tracking by quantifying multiple contrast agents simultaneously, but faster scan times are required for in vivo applications. Sliding window (SW)-MRF is one option for accelerating MRF, but standard implementations are not sufficient to preserve the accuracy of T2*, which is critical for tracking iron-labelled cells in vivo.

PURPOSE

To develop a SW approach to MRF which preserves the T2* accuracy required for accelerated concentration mapping of iron-labelled cells on single-channel preclinical systems.

METHODS

A nonuniform SW was applied to the MRF sequence and dictionary. Segments of the sequence most sensitive to T2* were subject to a shorter window length, preserving the T2* sensitivity. Phantoms containing iron-labelled CD8+ T cells and gadolinium were used to compare 24× undersampled uniform and nonuniform SW-MRF parameter maps. Dual concentration maps were generated for both uniform and nonuniform MRF and compared.

RESULTS

Lin's concordance correlation coefficient, compared to gold standard parameter values, was much greater for nonuniform SW-MRF than for uniform SW-MRF. A Wilcoxon signed-rank test showed no significant difference between nonuniform SW-MRF and gold standards. Nonuniform SW-MRF outperformed the uniform SW-MRF concentration maps for all parameters, providing a balance between T2* sensitivity of short window lengths, and SNR of longer window lengths.

CONCLUSIONS

Nonuniform SW-MRF improves the accuracy of matching compared to uniform SW-MRF, allowing higher accelerated concentration mapping for preclinical systems.

Use of Magnetotactic Bacteria as an MRI Contrast Agent for In Vivo Tracking of Adoptively Transferred Immune Cells

PURPOSE

In vivo immune cell tracking using MRI can be a valuable tool for studying the mechanisms underlying successful cancer therapies. Current cell labeling methods using superparamagnetic iron oxide (SPIO) lack the persistence to track the fate and location of transplanted cells long-term. Magnetospirillum magneticum is a commercially available, iron-producing bacterium that can be taken up by and live harmoniously within mammalian cells as magneto-endosymbionts (MEs). MEs have shown promise as labeling agents for in vivo stem and cancer cell tracking but have yet to be evaluated in immune cells. This pilot study examined ME labeling in myeloid-derived suppressor cells (MDSCs), cytotoxic T lymphocytes (CTLs), and dendritic cells (DCs) and its effects on cell purity, function, and MRI contrast.

PROCEDURES

MDSCs, CTLs, and DCs were incubated with MEs at various ME labeling ratios (MLR), and various biological metrics and iron uptake were assessed. For in vivo imaging, MDSCs were labeled overnight with either MEs or SPIO (Molday ION Rhodamine B) and injected into C3 tumor-bearing mice via tail vein injection 24 days post-implant and scanned daily with MRI for 1 week to assess cellular quantification.

RESULTS

Following incubations, MDSCs contained > 0.6 pg Fe/cell. CTLs achieved Fe loading of < 0.5 pg/cell, and DCs achieved Fe loading of ~ 1.4 pg/cell. The suppressive functionality of MDSCs at 1000 MLR was not affected by ME labeling but was affected at 2000 MLR. Markers of CTL dysfunction were not markedly affected by ME labeling nor were DC markers. In vivo data demonstrated that the MDSCs labeled with MEs generated sufficient contrast to be detectable using TurboSPI, similar to SPIO-labeled cells.

CONCLUSIONS

Cells can be labeled with sufficient numbers of MEs to be detectable with MRI without compromising cell viability. Care must be taken at higher concentrations of MEs, which may affect some cell types' functional activity and/or morphology. Immune cells with minimal phagocytic behavior have much lower iron content per cell after incubation with MEs vs SPIO; however, MEs can successfully be used as a contrast agent for phagocytic immune cells.

Geometrically accurate real-time volumetric visualization of the middle ear using optical coherence tomography

We introduce a novel system for geometrically accurate, continuous, live, volumetric middle ear optical coherence tomography imaging over a 10.9mm×30∘×30∘ field of view (FOV) from a handheld imaging probe. The system employs a discretized spiral scanning (DC-SC) pattern to rapidly collect volumetric data and applies real-time scan conversion and lateral angular distortion correction to reduce geometric inaccuracies to below the system's lateral resolution over 92% of the FOV. We validate the geometric accuracy of the resulting images through comparison with co-registered micro-computed tomography (micro-CT) volumes of a phantom target and a cadaveric middle ear. The system's real-time volumetric imaging capabilities are assessed by imaging the ear of a healthy subject while performing dynamic pressurization of the middle ear in a Valsalva maneuver.

Gabapentin, a human therapeutic medication and an environmental substance transferring at trace levels to horses: a case report

Gabapentin, 1-(Aminomethyl)cyclohexaneacetic acid, MW 171.240, is a frequently prescribed high dose human medication that is also used recreationally. Gabapentin is orally absorbed; the dose can be 3,000 mg/day and it is excreted essentially unchanged in urine. Gabapentin is stable in the environment and routinely detected in urban wastewater. Gabapentin randomly transfers from humans to racing horses and is at times detected at pharmacologically ineffective / trace level concentrations in equine plasma and urine. In Ohio racing between January 2019 and July 2020,18 Gabapentin identifications, all less than 2 ng/ml in plasma, were reported. These identifications were ongoing because the horsemen involved were unable to pin down and therefore avoid the source of these identifications. Given that 44 ng/ml or less is an Irrelevant Plasma Concentration (IPC) of Gabapentin in horses, we proposed a 5 ng/ml plasma interim Screening Limit of Detection for Gabapentin identifications in Ohio racing, and an essentially similar 8 ng/ml plasma Screening Limit of Detection was suggested by a scientific advisor to the Ohio Horse Racing Commission. As such, an analytical Screening Limit of 8 ng /ml in plasma is an appropriate and pharmacologically conservative analytical "cut-off" or Screening Limit of Detection (SLOD) for Gabapentin in equine competitive events to avoid the calling of "positive" identifications on random unavoidable trace level identifications of this widely prescribed human therapeutic medication in equine forensic samples.

Bipolar Stigma in Jewish Communities in the United States

Introduction

This study investigated differences in mood disorder public stigma endorsed by Jewish adults. Specifically, it examined the association between public stigma and the symptomatology and gender of individuals with mood disorders and characteristics of respondents. The symptomatology investigated included major depressive disorder and bipolar disorder presenting with mania or depression. The public stigma factors measured for mood disorders were recovery, relationship disruption, hygiene, anxiety, and treatment/professional efficacy.

Objectives

Do symptomatology and gender predict stigma for mood disorders? For Jewish adults, do gender, age, religious characteristics, mental health history, and perceived stigma for mental illness predict their stigma toward individuals with mood disorders?

Methods

A convenience sample of 243 Jewish adults were randomly administered vignettes using a factorial design. MANCOVA was used for analysis. The Mental Illness Stigma Scale (Day et al., 2007) and the Devaluation of Consumer scale (Struening et al., 2001) were used to measure public and perceived stigma respectively.

Results

showed that recovery, relationship disruption, and hygiene stigmas were associated with vignette subject symptomatology, an interaction was found between respondent gender and age for treatability/professional efficacy stigma, and perceived stigma was correlated with public stigma factors. Consistent with previous research, the highest levels of stigma were found for individuals with bipolar disorder presenting with mania (Wolkenstein & Meyer, 2008).

Conclusions

These findings increase our knowledge of mood disorder stigma existing in the Jewish community and supports research showing that bipolar disorder presenting with mania is the most stigmatized type of mood disorder symptomatology (Wolkenstein & Meyer, 2008).

Disclosure

No significant relationships.

Sporadic worldwide "clusters" of feed driven Zilpaterol identifications in racing horses: a review and analysis

Zilpaterol is a β2-adrenergic agonist medication approved in certain countries as a cattle feed additive to improve carcass quality. Trace amounts of Zilpaterol can transfer to horse feed, yielding equine urinary "identifications" of Zilpaterol. These "identifications" occur because Zilpaterol is highly bioavailable in horses, resistant to biotransformation and excreted as unchanged Zilpaterol in urine, where it has a 5 day or so terminal half-life.In horses, urinary steady-state concentrations are reached 25 days (5 half-lives) after exposure to contaminated feed. Zilpaterol readily presents in horse urine, yielding clusters of feed related Zilpaterol identifications in racehorses. The first cluster, April 2013, involved 48 racehorses in California; the second cluster, July 2013, involved 15 to 80 racehorses in Hong Kong. The third cluster, March 2019, involved 24 racehorses in Mauritius; this cluster traced to South African feedstuffs, triggering an alert concerning possible Zilpaterol feed contamination in South African racing. The fourth cluster, September/October 2020 involved 18 or so identifications in French racing, reported by the French Laboratories des Courses Hippiques, (LCH), and in July 2021, a fifth cluster of 10 Zilpaterol identifications in South Africa.The regulatory approach to these identifications has been to alert horsemen and feed companies and penalties against horsemen are generally not implemented. Additionally, given their minimal exposure to Zilpaterol, there is little likelihood of Zilpaterol effects on racing performance or adverse health effects for exposed horses.The driving factor in these events is that Zilpaterol is dissolved in molasses for incorporation into cattle feed. Inadvertent incorporation of Zilpaterol containing molasses into horse feed was the source of the California and Hong Kong Zilpaterol identifications. A second factor in the 2019 Mauritius and 2020 French identifications was the sensitivity of testing for Zilpaterol in Mauritius and France, with the French laboratory reportedly testing at a "more sensitive level for Zilpaterol". As of January 1^st, 2021, the new FEI Atypical Finding (ATF) policy specifies Zilpaterol as a substance to be treated as an Atypical Finding (ATF), allowing consideration of inadvertent feed contamination in the regulatory evaluation of Zilpaterol identifications.

Precision dosimetry in yttrium-90 radioembolization through CT imaging of radiopaque microspheres in a rabbit liver model

PURPOSE

To perform precision dosimetry in yttrium-90 radioembolization through CT imaging of radiopaque microspheres in a rabbit liver model and to compare extracted dose metrics to those produced from conventional PET-based dosimetry.

MATERIALS AND METHODS

A CT calibration phantom was designed containing posts with nominal microsphere concentrations of 0.5 mg/mL, 5.0 mg/mL, and 25.0 mg/mL. The mean Hounsfield unit was extracted from the post volumes to generate a calibration curve to relate Hounsfield units to microsphere concentration. A nominal bolus of 40 mg of microspheres was administered to the livers of eight rabbits, followed by PET/CT imaging. A CT-based activity distribution was calculated through the application of the calibration curve to the CT liver volume. Post-treatment dosimetry was performed through the convolution of yttrium-90 dose-voxel kernels and the PET- and CT-based cumulated activity distributions. The mean dose to the liver in PET- and CT-based dose distributions was compared through linear regression, ANOVA, and Bland-Altman analysis.

RESULTS

A linear least-squares fit to the average Hounsfield unit and microsphere concentration data from the calibration phantom confirmed a strong correlation (r2 > 0.999) with a slope of 14.13 HU/mg/mL. A poor correlation was found between the mean dose derived from CT and PET (r2 = 0.374), while the ANOVA analysis revealed statistically significant differences (p < 10-12) between the MIRD-derived mean dose and the PET- and CT-derived mean dose. Bland-Altman analysis predicted an offset of 15.0 Gy between the mean dose in CT and PET. The dose within the liver was shown to be more heterogeneous in CT than in PET with an average coefficient of variation equal to 1.99 and 1.02, respectively.

CONCLUSION

The benefits of a CT-based approach to post-treatment dosimetry in yttrium-90 radioembolization include improved visualization of the dose distribution, reduced partial volume effects, a better representation of dose heterogeneity, and the mitigation of respiratory motion effects. Post-treatment CT imaging of radiopaque microspheres in yttrium-90 radioembolization provides the means to perform precision dosimetry and extract accurate dose metrics used to refine the understanding of the dose-response relationship, which could ultimately improve future patient outcomes.

Mapping of fatty acid composition with free-breathing MR spectroscopic imaging and compressed sensing

Nonalcoholic fatty liver disease (NAFLD) is a growing health problem, and a major challenge in NAFLD management is identifying which patients are at risk of progression to more serious disease. Simple measurements of liver fat content are not strong predictors of clinical outcome, but biomarkers related to fatty acid composition (ie, saturated vs. unsaturated fat) may be more effective. MR spectroscopic imaging (MRSI) methods allow spatially resolved, whole-liver measurements of chemical composition but are traditionally limited by slow acquisition times. In this work we present an accelerated MRSI acquisition based on spin echo single point imaging (SE-SPI), which, using appropriate sampling and compressed sensing reconstruction, allows free-breathing acquisition in a mouse model of fatty liver disease. After validating the technique's performance in oil/water phantoms, we imaged mice that had received a normal diet or a methionine and choline deficient (MCD) diet, some of which also received supplemental injections of iron to mimic hepatic iron overload. SE-SPI was more resistant to the line-broadening effects of iron than single-voxel spectroscopy measurements, and was consistently able to measure the amplitudes of low-intensity spectral peaks that are important to characterizing fatty acid composition. In particular, in the mice receiving the MCD diet, SE-SPI showed a significant decrease in a metric associated with unsaturated fat, which is consistent with the literature. This or other related metrics may therefore offer more a specific biomarker of liver health than fat content alone. This preclinical study is an important precursor to clinical testing of the proposed method. MR-based quantification of fatty acid composition may allow for improved characterization of non-alcoholic fatty liver disease. A spectroscopic imaging method with appropriate sampling strategy allows whole-liver mapping of fat composition metrics in a free-breathing mouse model. Changes in metrics like the surrogate unsaturation index (UIs) are visible in mice receiving a diet which induces fat accumulation in the liver, as compared to a normal diet; such metrics may prove useful in future clinical studies of liver disease.

Dexamethasone serum concentrations after intravenous administration in horses during race training

Dexamethasone (DXM) sodium phosphate is a widely used corticosteroid for inflammatory conditions in horses, regulated in racing jurisdictions in the USA by a 0.005 ng/ml serum/plasma threshold. This study seeks to describe serum concentrations of DXM at 48 and 72 h after intravenous administration of 20 mg DXM sodium phosphate over 1 to 5 days, and to identify a possible source of DXM overages. 74 horses (39 Thoroughbreds, 13 Standardbreds, 22 Quarter Horses) in active race training received 20 mg DXM sodium phosphate. Serum was collected before injection, at 48 and 72 h post last injection, and analysed by LC/MS-MS (limit of quantification (LOQ) = 2.5 pg/ml). No differences were identified by ANOVA (P≤0.05) for racing breeds, age, gender or the number of days of DXM sodium phosphate administration, so data were pooled for each time point. The DXM serum concentration at 48 h (mean ± standard deviation, range) was 2.18±1.56 pg/ml (<2.5 to 40 pg/ml). Summary statistics could not be derived for 72 h DXM serum concentration data owing to censored data, but ranged from <2.5 to 95.8 pg/ml. There was one extreme outlier (Tukey) at 48 h, and two extreme outliers at 72 h. A separate study was conducted using sedentary experimental horses to determine the likelihood that positive DXM samples could result from environmental transfer. Urine was collected from a mare 2 to 3 h post administration of 20 mg DXM. Hay with 100 ml of the DXM (17 ng/ml) containing urine was offered to each of six experimental horses and blood was collected at 0, 4, 8, 12, 16, 20 and 24 h. All six horses had plasma DXM concentration above the limit of detection and five of six had plasma DXM concentrations above the LOQ for at least one sample time.

Simultaneous quantification of SPIO and gadolinium contrast agents using MR fingerprinting

PURPOSE

Develop a magnetic resonance fingerprinting (MRF) methodology with R₂^∗ quantification, intended for use with simultaneous contrast agent concentration mapping, particularly gadolinium (Gd) and iron labelled CD8+ T cells.

METHODS

Variable-density spiral SSFP MRF was used, modified to allow variable TE, and with an exp.(-TE·R₂^∗) dictionary modulation. In vitro phantoms containing SPIO labelled cells and/or gadolinium were used to validate parameter maps, probe undersampling capacity, and verify dual quantification capabilities. A C57BL/6 mouse was imaged using MRF to demonstrate acceptable in vivo resolution and signal at 8× undersampling necessary for a 25-min scan.

RESULTS

Strong agreement was found between conventional and MRF-derived values for R₁, R₂, and R₂^∗. Expanded MRF allowed quantification of iron-loaded CD8+ T cells. Results were robust to 8× undersampling and enabled recreation of relaxation profiles for both a Gd agent and iron labelled cells simultaneously. In vivo data demonstrated sufficient SNR in undersampled data for parameter mapping to visualise key features.

CONCLUSION

MRF can be expanded to include R₁, R₂, and R₂^∗ mapping required for simultaneous quantification of gadolinium and SPIO in vitro, allowing for potential implementation of a variety of future in vivo studies using dual MR contrast agents, including molecular imaging of labelled cells.

Abstract 384: T cell infiltration into tumors induced by DPX-Survivac combination immunotherapy demonstrated by PET/MRI imaging in an orthotopic ovarian cancer model

Introduction: Epithelial ovarian cancers are highly aggressive and often diagnosed at late stages. To date, a limited number of these patients benefit from immunotherapies, and recurrent ovarian cancer remains an area of unmet medical need. Novel immunotherapies that generate and drive activated T cells into tumors, such as DPX-Survivac, represent a promising approach. To better understand the underlying mechanisms of action of this novel immunotherapy and how it may correlate with clinical outcomes, we used an orthotopic ovarian cancer model and a dual approach using molecular imaging to track immune cells in vivo followed by biological assays.

Methods: Humanized transgenic mice (HLA-A2.1-/HLA-DR1; H-2 class-I/II knockout) were implanted with 104 syngeneic mouse ovarian surface epithelial cells in the left ovarian bursa and were either untreated or treated with DPX-Survivac, intermittent low dose cyclophosphamide and anti-PD-1. The CD8+ cytotoxic T cells (CTLs) and myeloid cells (MCs) were isolated from disease matched mice, cultured in vitro, loaded with superparamagnetic iron oxide (SPIO) nanoparticles, and injected i.v. in recipient mice. The next day, recipient mice were injected with 500µCi of 18F-fluorodeoxyglucose and imaged by magnetic resonance (MRI) and positron emission tomography (PET). Anatomical images and tumor volumes were collected with a balance steady-state free precession sequence, cells were semi-quantified using R2* maps from a multi-echo single point imaging sequence (TurboSPI) and tumor metabolism was assessed by simultaneous acquisition of PET. Mice were imaged days 41, 49, and 56 post-implant. CTLs and MCs were characterized by flow cytometry (FC) before injection into recipient mice. Following imaging completion, tumors and lymph nodes (LN) were assayed for tumor infiltrating lymphocytes. Ascites were analyzed for tumor cell to lymphocyte content by FC.

Results: PET/MRI images showed that the combination immunotherapy significantly decreased primary tumor burden and improved survival rates. The recruitment of isolated CTLs and MCs was detected in both tumors and LNs. CTL recruitment to tumors was increased in mice receiving combination immunotherapy while MCs recruitment was decreased. CTLs were recruited at a higher rate to the DPX-Survivac draining LN than tumor draining LN and MCs were equally recruited to both. The expression of checkpoint inhibitor molecules on CTL did not appear to vary with treatment. CTLs from treated mice expressed higher rates of Ki67 (a proliferative marker) than CTLs from untreated mice. The treatment increased the lymphocyte:tumor cell ratio within the tumors of treated animals and included a population of CD8/CD4 double positive (DP) T cells. Differences in tumor infiltrating lymphocyte phenotype correlated with tumor burden.

Conclusions: DPX-Survivac combination immunotherapy induces the recruitment of CD8+ T cells into tumors, resulting in tumor control in an orthotopic ovarian cancel model.

Citation Format: Marie-Laurence Tremblay, Caitrin Sobey-Skelton, Hailey Wyatt, Victoria Gonzalez, Andrea Nuschke, Christa Davis, Alecia Mackay, Kim Bobbit, Andrea West, Barbara Vanderhyden, Genevieve Weir, Alexandra Merkx-Jacques, Kimberly Brewer, Marianne Stanford. T cell infiltration into tumors induced by DPX-Survivac combination immunotherapy demonstrated by PET/MRI imaging in an orthotopic ovarian cancer model [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 384.

An interim screening limit of detection for naproxen in equine plasma: a review and analysis

Starting in August 2015 Thoroughbred racing in Charles Town, West Virginia experienced a sequence of intermittent low concentration Naproxen identifications from 6.3 to 161 ng/ml of plasma (27.3 to 699 nM). These identifications were ongoing, indicating the horsemen were unaware of their origins. Naproxen is administered orally to horses at substantial doses and is chemically stable in the environment. These identifications are therefore most likely associated with exposure of these horses to environmental traces of Naproxen. Given the low concentrations of these identifications, we were asked to identify a Screening Limit of Detection (SLOD) below which these trace level Naproxen identifications would not be reported. Review of the data set suggested an SLOD of 200 ng/ml, while outlier analysis suggested an ‘extreme’ outlier level at 247 ng/ml, which figure was rounded up to 250 ng/ml Naproxen or 1.09 uM. This proposed SLOD is in good agreement with other US regulatory thresholds for therapeutic medications and this Interim Screening Limit of Detection was presented for review.

Clinical signs associated with a case of iatrogenic poisoning by a turpentine-based commercial product in a 3-day-old foal

The aim of this study is to report a case of iatrogenic poisoning by a turpentine-based commercial product in a 3-day-old foal and the successful treatment of this condition. A 3-day-old male foal presented with acute cardio-respiratory collapse, anaphylactic shock, severe respiratory distress, dyspnea and pulmonary edema. The animal’s history included previous administration of a commercial veterinary product (UNITIPAN). Clinical examination revealed: temperature: (39.9 °C), pulse: 135 bpm, respiration: 51 bpm, mucous membranes: moist and congested, capillary refill time: 3 sec or less. The foal was treated with emergency hydration, duphalyte, steroidal anti-inflammatory, atropine sulphate and antibiotic. After 6 h of treatment, the foal was stabilized and vital signs were normalized 8 h after treatment start.

Abstract 873: Evaluating immunotherapy effects using preclinical molecular imaging tools for quantitative immune cell tracking

Immunotherapies are a promising class of cancer therapeutics, but clinical translation is often hampered by a lack of understanding regarding optimal therapy administration, combination, and reliable biomarkers of success. Traditional metrics such as RECIST, and modern metrics like irRC and PERCIST used for monitoring cancer therapy outcome, have limitations for immunotherapy evaluation and are not always reflective of the underlying immune mechanisms. We aim to better characterize and monitor these immunotherapies, with focus on combination therapy optimization, by tracking immune cell migration in response to these therapies using preclinical magnetic resonance imaging (MRI). MRI is used to obtain anatomical tumor changes, detect and quantify superparamagnetic iron oxide (SPIO)-labeled cells in vivo.

Goal: To link immune cell migration to early prognostic biomarkers for immunotherapy success.

Methods: C57/BL6 mice (n=40) received an implant of 5x105 C3 cancer cells in the left flank. Mice (n=10/group) were i) untreated or treated with ii) 200µg of anti-PD1/day on days 7, 9, 11, 21 and 25, iii) the peptide-based vaccine DepoVaxTM (DPX) on day 15, or iv) with anti-PD1 and DPX. CD8+ cytotoxic T cells (CD8) and suppressive regulatory T cells (Tregs) were isolated from diseased-matched & treated donor mice for expansion in culture before labeling with SPIO for adoptive cell transfer into mice receiving scans. PET/MRI Data: Anatomical and qualitative SPIO data is collected using a balanced steady-state free precession (bSSFP) sequence. Iron quantification is done using R2* maps from a multi-echo single point imaging sequence (TurboSPI). Tumor metabolism was assessed by 18F-fluorodeoxyglucose uptake during simultaneous acquisition of positron emission tomography (PET) with MRI. Imaging was done 21 and 28 days post-implant.

Results: CD8 and Treg cells are consistently recruited to both the tumor and vaccine draining inguinal lymph nodes. CD8 T cells are primarily recruited to the tumor periphery and do not always penetrate the tumor core. Positive therapy outcomes are correlated with an increasing CD8/Treg ratio in the tumor, particularly at earlier time points (21 vs 28 days). In certain cases, CD8 T cells were found within the fat pad between the tumor and lymph node. As expected, DPX & anti-PD1 combination therapy resulted in the best prognosis. Simultaneous acquisition of PET/MRI demonstrated large areas of necrosis in tumor cores. Using TurboSPI, we have begun quantifying CD8 and Tregs cells, evaluating if volumetric tumor changes due to pseudoprogression correlate with Treg or CD8 T cell migration and comparing results to pre-existing biomarkers.

Conclusions: Using MRI/PET with quantitative immune cell tracking results in more in-depth, longitudinal, characterization of immunotherapies at the preclinical level, which can be used to optimize therapy combinations.

Citation Format: Marie-Laurence Tremblay, Zoe O'Brien-Moran, Christa Davis, Kimberly Brewer. Evaluating immunotherapy effects using preclinical molecular imaging tools for quantitative immune cell tracking [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 873. doi:10.1158/1538-7445.AM2017-873

Beyond the crisis: Ongoing psychiatric treatment and service utilization after initial symptom stabilization following first-episode psychosis for adolescents

Introduction

The importance of timely identification and treatment of psychosis are increasingly the focus of early interventions, with research targeting the initial high-risk period in the months following first-episode hospitalization. However, ongoing psychiatric treatment and service utilization after the symptoms have been stabilized over the initial years following first-episode has received less research attention.

Objectives

To model the variables predicting continued service utilization with psychiatrists for adolescents following their first-episode psychosis; examine associated temporal patterns in continued psychiatric service utilization.

Methods

This study utilized a cohort design to assess adolescents (age 14.4 ± 2.5 years) discharged following their index hospitalization for first-episode psychosis. Bivariate analyses were conducted on predictor variables associated with psychiatric service utilization. All significant predictor variables were included in a logistic regression model.

Results

Variables that were significantly associated with psychiatric service utilization included: diagnosis with a schizophrenia spectrum disorder rather than major mood disorder with psychotic features (OR = 24.0; P = 0.02), a first degree relative with depression (OR = 0.12; P = 0.05), and months since last psychiatric inpatient discharge (OR = 0.92; P = 0.02). Further examination of time since last hospitalization found that all adolescents continued service utilization up to 18 months post-discharge.

Conclusions

Key findings highlight the importance of early diagnosis, that a first degree relative with depression may negatively influence the adolescent's ongoing service utilization, and that 18 months post-discharge may a critical time to review current treatment strategies and collaborate with youth and families to ensure that services continue to meet their needs.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

A cluster of trace-concentration methamphetamine identifications in racehorses associated with a methamphetamine-contaminated horse trailer: A report and analysis

Three low concentration methamphetamine "positive" tests were linked to use of a methamphetamine-contaminated trailer to transport the affected horses. This incident establishes methamphetamine as a human-use substance that can inadvertently enter the environment of racing horses, resulting in urinary methamphetamine "positives;" an interim regulatory cut-off of 15 ng/mL for methamphetamine in post-race urine is proposed.

Cobalt use and regulation in horseracing: a review

Cobalt, atomic weight 58.9, is a metallic element and environmental substance found in the animal in microgram quantities, predominantly as vitamin B12, but is also a component of at least one mammalian enzyme unassociated with B12. Cobalt is a required trace mineral and has long been administered as a dietary supplement to humans and animals. Cobalt deficiency outside of its requirement in vitamin B12 has not been reported in humans. The administration of cobalt salts was once standard treatment for anaemia in humans, owing to its ability to stimulate red blood cell synthesis. Elemental cobalt acts by stabilising hypoxia inducible factor (HIF-1α), which activates the erythropoietin gene, which in turn increases haemoglobin/red blood cell synthesis, which had led to a presumption that cobalt may be performance enhancing in athletes. Administration of cobalt in amounts sufficient to significantly increase the haematocrit are associated with risk of toxicity in humans, and the only cobalt administration study in horses showed no effect on red blood cell parameters or toxicity. Because of the perception that cobalt administration may enhance athletic performance, racing regulators have recently begun to restrict cobalt use in horseracing which has led to the introduction of cobalt thresholds in several racing jurisdictions. The International Federation of Horseracing Authorities is considering an international regulatory threshold for cobalt of 100 ng/ml in urine, based on studies performed in five different countries. In the United States, the Racing Commissioners International has recently set a primary plasma threshold of 25 ng/ml and secondary threshold of 50 ng/ml. One New York and New Jersey racetrack owner has initiated testing for cobalt and has denied his facilities to trainers whose horses tested positive for excessive quantities of cobalt. This review seeks to summarise what is known about the use of cobalt in horse racing.

Sudden death, aortic rupture in horses, literature review, case studies reported and risk factors

<p>As mortes súbitas de cavalos em várias provas equestres têm sido atribuídas a doenças respiratórias e cardiovasculares agudas e crônicas. O objetivo deste estudo foi efetuar uma revisão de literatura da ruptura da aorta em cavalos analisando estudos de caso e estabelecendo os possíveis fatores de risco. Na revisão da literatura no período de 28 anos (1986-2014) foram localizados 137 casos de ruptura da aorta em cavalos com aproximadamente cinco cavalos morrendo por essa causa por ano. Histologicamente, são observadas alterações macroscópicas discretas degenerativas na camada íntima da aorta. A avaliação histológica na porção inicial da aorta do coração evidencia alterações degenerativas com perda de continuidade e distribuição das fibras elásticas. Fatores de risco para a ruptura da aorta dos cavalos são: ruptura espontânea associada com hipertensão, lesão vascular pré-existente (aneurisma), cardiomiopatia dilatada ou hipertrófica, níveis de cobre no endotélio, fatores genéticos, tais como a consanguinidade na criação, toxicologia e aspectos farmacológicos. A ruptura aórtica mostra semelhança com hemorragia pulmonar induzida pelo exercício. Em conclusão, alterações degenerativas discretas das fibras elásticas da íntima da aorta parecem predispor a ruptura da parede da aorta, no momento da pressão máxima de sangue durante o exercício determinando o consequente colapso e morte do cavalo atleta.</p>

Scopolamine in racing horses: trace identifications associated with dietary or environmental exposure

Scopolamine (L-hyoscine) identifications, often in small-number clusters, have been reported worldwide in performance horses over the last 30 years. Scopolamine is an Association of Racing Commissioners International (ARCI) class 3, penalty class B, substance with potential to affect performance. As such, scopolamine identification(s) in race or performance horses can result in significant penalties for the connections of the horse(s). Reviewed here is the worldwide distribution of scopolamine containing plants (primarily Datura spp.), with estimates of their potential toxicity to horses through dietary and/or environmental exposure. Also reviewed are the basic pharmacology of scopolamine and its precursor, urinary concentrations following feedstuff exposure, and the probable pharmacological/forensic significance of such findings. Based on an overview of the world literature on scopolamine, the expected characteristics of inadvertent environmental exposure are also presented with a view to making clear the potential of scopolamine identifications, with or without atropine, as a direct and expected outcome of both the worldwide distribution of scopolamine-containing plants and the sensitivity of modern equine drug testing. It is of particular interest that only 2/30 reported post-event equine identifications of scopolamine have been associated with atropine, suggesting that failure to identify atropine is not a biomarker of pharmaceutical administration of scopolamine. Available quantitative information associated with scopolamine identifications is consistent with the 75 ng/mL regulatory threshold for scopolamine currently used in Louisiana racing in the USA and the 30 ng/mL reporting threshold in effect in European racing.

A clinician's guide to factors affecting withdrawal times for equine therapeutic medications

Equine forensic science can now detect concentrations down to 25 femtograms/mL (parts per quadrillion, ppq) or less in blood and urine. As such, horsemen are increasingly at risk of inadvertent 'positives' due to therapeutic medication 'overages' or trace identifications of dietary or environmental substances. Reviewed here are the factors which determine detection times and 'withdrawal times' for substances administered to horses. Withdrawal times are affected by many factors, including dose, formulation, route and frequency of administration, bioavailability, plasma half-life, sensitivity of the analytical process, the testing matrix (plasma, urine, or other), and the environmental presence and/or persistence of administered substances. Of these factors only dose is known precisely. For any given administration, horse-to-horse differences in the volumes of distribution, systemic clearance, and terminal plasma elimination half-life of substances are major and totally uncontrollable factors driving horse-to-horse variability in withdrawal times. A further complication is that chemically stable medications administered to horses and eliminated in the urine inevitably become part of the environment of the horse. The presence of these substances in the equine environment is increasingly giving rise to trace identifications long after nominal administration of these substances has ceased. Because of the unknown and uncontrollable horse-to-horse variability in medication pharmacokinetics, any therapeutic medication administration to a horse by definition includes the possibility of an inadvertent medication overage. As such, the caveat that there are no guarantees in life most assuredly applies to advisories concerning equine therapeutic medication withdrawal times.

Roles of mechanical forces and collagen failure in the development of elastase-induced emphysema

Emphysema causes a permanent destruction of alveolar walls leading to airspace enlargement, loss of elastic recoil, decrease in surface area for gas exchange, lung hyperexpansion, and increased work of breathing. The most accepted hypothesis of how emphysema develops is based on an imbalance of protease and antiprotease activity leading to the degradation of elastin within the fiber network of the extracellular matrix. Here we report novel roles for mechanical forces and collagen during the remodeling of lung tissue in a rat model of elastase-induced emphysema. We have developed a technique to measure the stress-strain properties of tissue sections while simultaneously visualizing the deformation of the immunofluorescently labeled elastin-collagen network. We found that in the elastase treated tissue significant remodeling leads to thickened elastin and collagen fibers and during stretching, the newly deposited elastin and collagen fibers undergo substantially larger distortions than in normal tissue. We also found that the threshold for mechanical failure of collagen, which provides mechanical stability to the normal lung, is reduced. Our results indicate that mechanical forces during breathing are capable of causing failure of the remodeled extracellular matrix at loci of stress concentrations and so contribute to the progression of emphysema.

Subject and observer-rated quality of life in schizophrenia

OBJECTIVE

We aimed to explore the relationship between objectively rated quality of life and subjective measures of social functioning and life satisfaction.

METHOD

Participants of the Schizophrenia Care and Assessment Program (SCAP) study at Dandenong in Australia were included in this analysis. Subjective ratings of several domains of social functioning and life satisfaction were taken from the SCAP instrument and comparisons made with data from the Quality of Life scale rated by research staff as well as several psychopathology measures.

RESULTS

Subjectively reported life satisfaction was not related to positive or negative symptoms of schizophrenia but did correlate with depressive symptoms. Quality of Life scale measures correlated with negative symptoms on most domains. There was very limited overlap in domain items between the life satisfaction and quality of life measures.

CONCLUSION

Life satisfaction and objectively rated quality of life are not closely related and appear to have different determinants in patients with schizophrenia.

A controlled trial of topical nitroglycerin in a New Zealand white rabbit model of brown recluse spider envenomation

STUDY OBJECTIVES

Topical nitroglycerin has been reported to prevent skin necrosis from brown recluse spider bites, but this has never been scientifically tested. This study attempts to assess the effects of topical nitroglycerin on experimental Loxosceles reclusa envenomations.

METHODS

We performed a randomized, blinded, controlled study in an animal care facility. Twenty-four New Zealand white rabbits were experimentally envenomated by means of subcutaneous injection with 20 microg of brown recluse spider venom. Rabbits were randomized to 1 of 2 experimental groups. The treatment group received 1 in of 2% topical nitroglycerin ointment every 6 hours for 3 days applied directly to the envenomation site. The control group received the vehicle without nitroglycerin. Gross examination of the lesions and measurements of the areas of the lesions were made daily. Creatine phosphokinase (CPK), blood urea nitrogen, creatinine, hemoglobin, and hematocrit levels were measured on days 0, 5, and 10. Lesions were excised after 10 days and examined by a blinded pathologist, who measured the area of necrosis and quantified inflammation and edema using a standard wound-healing score. For all values, mean values plus SD were determined. All comparisons made over multiple time points were assessed for significance by using a repeated-measures analysis of variance followed by Fisher least significant difference and Scheffé post hoc comparisons. A P value of.05 or less was used to determine significance. The Student's t test was used to compare the means of single measures. Significance was determined by using 95% confidence intervals. Comparisons of total area of necrosis were made with the nonparametric Mann-Whitney U test because of the heavy positive skew of the data.

RESULTS

Skin necrosis developed in all animals. Mean values of the lesion area were not significantly different over time between the 2 groups of animals. At day 10, the median area of necrosis was 22.3 cm2 for the treatment group and 15.4 cm2 for the control group (P =.12). The inflammation score was 3.33+/-0.78 for the treatment group and 2.79+/-1.29 for the control group (P < .01). The edema score was 1.25+/-1.28 for the treatment group and 0.98+/-1.10 for the control group (not significantly different). CPK levels increased dramatically in both groups, with the greatest increase in the treatment group. In both groups hemoglobin and hematocrit levels decreased significantly, whereas WBC counts and platelet counts increased significantly, without significant differences between the 2 groups.

CONCLUSION

At the dose used in this experiment, topical nitroglycerin did not prevent skin necrosis, increased inflammation score, and increased serum CPK levels. The results of this study do not support the use of topical nitroglycerin in the treatment of L reclusa envenomation and suggest that systemic toxicity could be increased.

Involvement of capsaicin-sensitive sensory neurons in stress-induced gastroduodenal mucosal injury in rats

The pathogenesis of stress-induced gastroduodenal mucosal injury is complex and incompletely understood. The aim of this investigation was to examine the involvement of gastric and duodenal capsaicin-sensitive neurons in mucosal damage associated with water-restraint stress (WRS) in rats. Following WRS, gastroduodenal mucosal injury was quantitated by macroscopic and microscopic methods. Calcitonin gene-related peptide (CGRP) content was measured by radioimmunoassay. WRS-induced mucosal erosive injury in the stomach and duodenum (40.9 +/- 4.2 and 5.1 +/- 0.6 mm2, respectively) was reduced significantly (by 88% and 67%, respectively) by acute intragastric capsaicin administration prior to WRS. In contrast, sensory denervation by chronic capsaicin significantly increased the area of gastric injury and duodenal damage. WRS alone caused a significant reduction (by 52% and -35%, respectively) in gastric and duodenal CGRP content, which was prevented by acute capsaicin treatment. The data suggest that gastric and duodenal sensory neurons and CGRP are involved in the pathogenesis of stress-induced mucosal injury to the stomach and duodenum.

Molecular basis of variant pseudo-hurler polydystrophy (mucolipidosis IIIC)

Mucolipidosis IIIC, or variant pseudo-Hurler polydystrophy, is an autosomal recessive disease of lysosomal hydrolase trafficking. Unlike the related diseases, mucolipidosis II and IIIA, the enzyme affected in mucolipidosis IIIC (N-Acetylglucosamine-1-phosphotransferase [GlcNAc-phosphotransferase]) retains full transferase activity on synthetic substrates but lacks activity on lysosomal hydrolases. Bovine GlcNAc-phosphotransferase has recently been isolated as a multisubunit enzyme with the subunit structure alpha(2)beta(2)gamma(2). We cloned the cDNA for the human gamma-subunit and localized its gene to chromosome 16p. We also showed, in a large multiplex Druze family that exhibits this disorder, that MLIIIC also maps to this chromosomal region. Sequence analysis of the gamma-subunit cDNA in patients from 3 families identified a frameshift mutation, in codon 167 of the gamma subunit, that segregated with the disease, indicating MLIIIC results from mutations in the phosphotransferase gamma-subunit gene. This is to our knowledge the first description of the molecular basis for a human mucolipidosis and suggests that the gamma subunit functions in lysosomal hydrolase recognition.

A web-based research tool for functional genomics of the microcirculation: the leukocyte adhesion cascade

OBJECTIVE

Currently, microvascular data are almost exclusively deposited in scholarly journals. With the increasing availability of molecular data and the construction of genomic databases, a need arises to organize physiological data in a more accessible format. The microcirculation is a functional system that spans all organ systems and shares certain characteristics of organization with metabolic pathways, which have successfully been organized around genomic information for several prokaryotes. Here, we present a web-based research and teaching tool (http:@hsc.Virginia.EDU/medicine/basic-sci/biomed/l ey/) that covers a small aspect of microcirculatory physiology, the leukocyte adhesion cascade.

METHODS

Currently, the site is organized in a flat-text mode with hypertext links to GenBank, Medline, and online journals where available.

RESULTS

The web-based research and education tool is useful for graduate student education, and as a research resource for genetic researchers interested in gene function and for physiologists and biomedical engineers interested in the molecular basis of the leukocyte adhesion cascade. Our effort is intended to be a beginning toward a distributed database for the microcirculation (microcirculation physiome. see http://www.bme.jhu.edu/news/microphys).

CONCLUSIONS

We invite all microvascular researchers to provide annotations and comments to make the research and teaching tool more useful to the scientific community.

Brief recall tasks and memory assessment in Alzheimer's disease

Memory measures that permit pattern and error analysis are useful in the differential diagnosis of dementia. However, little is known about the relative utility or relations among verbal memory tests of different lengths. A 6-item verbal learning test (6-VLT) that assesses qualitative performance features was developed and compared to 3-word recall and the California Verbal Learning Test (CVLT) in patients with Alzheimer's disease. Stronger correlations were observed between the 6-VLT and the CVLT. Significant relations were found between 6-VLT and CVLT indexes of learning, recall, and recognition (hits and false positive errors), although free recall errors were unrelated. Brief tasks such as the 6-VLT may provide more useful information regarding gross memory capacity than 3-word recall, although more challenging tasks may be required to elicit characteristic error patterns in Alzheimer's disease.

Molecular cloning and functional expression of two splice forms of human N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase

We have isolated and sequenced human cDNA and mouse genomic DNA clones encoding N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase (phosphodiester alpha-GlcNAcase) which catalyzes the second step in the synthesis of the mannose 6-phosphate recognition signal on lysosomal enzymes. The gene is organized into 10 exons. The protein sequence encoded by the clones shows 80% identity between human and mouse phosphodiester alpha-GlcNAcase and no homology to other known proteins. It predicts a type I membrane-spanning glycoprotein of 514 amino acids containing a 24-amino acid signal sequence, a luminal domain of 422 residues with six potential N-linked glycosylation sites, a single 27-residue transmembrane region, and a 41-residue cytoplasmic tail that contains both a tyrosine-based and an NPF internalization motif. Human brain expressed sequence tags lack a 102-base pair region present in human liver cDNA that corresponds to exon 8 in the genomic DNA and probably arises via alternative splicing. COS cells transfected with the human cDNA expressed 50-100-fold increases in phosphodiester alpha-GlcNAcase activity proving that the cDNA encodes the subunits of the tetrameric enzyme. Transfection with cDNA lacking the 102-base pair region also gave active enzyme. The complete genomic sequence of human phosphodiester alpha-GlcNAcase was recently deposited in the data base. It showed that our cDNA clone was missing only the 5'-untranslated region and initiator methionine and revealed that the human genomic DNA has the same exon organization as the mouse gene.

Purification and multimeric structure of bovine N-acetylglucosamine-1-phosphodiester alpha-N-acetylglucosaminidase

N-Acetylglucosamine-1-phosphodiester alpha-N-Acetylglucosaminidase (EC 3.1.4.45; phosphodiester alpha-GlcNAcase) catalyzes the second step in the synthesis of the mannose 6-phosphate determinant required for efficient intracellular targeting of newly synthesized lysosomal hydrolases to the lysosome. A partially purified preparation of phosphodiester alpha-GlcNAcase from bovine pancreas was used to generate a panel of murine monoclonal antibodies. The anti-phosphodiester alpha-GlcNAcase monoclonal antibody UC1 was coupled to a solid support and used to immunopurify the bovine liver enzyme 670,000-fold in two steps to apparent homogeneity with an overall yield of 14%. The purified phosphodiester alpha-GlcNAcase has a specific activity of 498 micromol of [3H]GlcNAc-alpha-phosphomannose-alpha-methyl cleaved per h per mg of protein using 0.5 mM [3H]GlcNAc-alpha-phosphomannose-alpha-methyl as substrate. The subunit structure of the enzyme was determined using a combination of analytical gel filtration chromatography, SDS-polyacrylamide gel electrophoresis, and amino-terminal sequencing. The data indicate that bovine phosphodiester alpha-GlcNAcase is a 272,000-Da complex of four identical 68,000-Da glycoprotein subunits arranged as two disulfide-linked homodimers. A soluble form of the enzyme, isolated from fetal bovine serum, showed the same subunit structure. Both forms of the enzyme reacted with a rabbit antibody raised to the amino-terminal peptide of the liver enzyme, suggesting that phosphodiester alpha-GlcNAcase is a type I membrane-spanning glycoprotein with its amino terminus in the lumen of the Golgi apparatus.

Effects of calcitonin gene-related peptide on somatostatin and gastrin gene expression in rat antrum

The ability of exogenous calcitonin gene-related peptide (CGRP) to regulate gastric somatostatin and gastrin messenger RNA was studied in vitro in rat antral mucosal/submucosal tissues. Somatostatin and gastrin mRNA were quantified by Northern and dot blot hybridization and regulatory peptides were measured by radioimmunoassay. Incubation of antral tissues in the presence of CGRP [1 x 10(-7) M] for 60 min resulted in a reciprocal increase in somatostatin and a decrease in gastrin release: 214.7+/-28.5 vs. control of 81.7+/-5.9 pg somatostatin per gram of tissue and 2.2+/-0.3 vs. control of 5.5+/-0.7 ng gastrin per gram of tissue (P < 0.001). CGRP caused parallel changes in somatostatin and gastrin mRNA levels: somatostatin mRNA increased by 212% from 0.40+/-0.02 to 1.25+/-0.09 absorbance units (AU) (P < 0.001) and gastrin mRNA decreased by 73% from 0.55+/-0.08 to 0.15+/-0.02 AU (P < 0.001). Somatostatin monoclonal antibody prevented CGRP-mediated inhibition of both gastrin release and gastrin mRNA levels. In conclusion, CGRP is capable of modulating both the secretion and gene expression of regulatory peptides from antral G and D cells. Somatostatin immunoneutralization studies suggest that the actions of CGRP on gastrin release and gene expression are indirect and mediated through the paracrine influences of somatostatin.

Mentorship and professional role development in undergraduate nursing education

Mentoring is a positive method for promoting professional development; however, there is little information in the literature addressing the use of mentoring with baccalaureate nursing students. Because professional socialization is a critical component of baccalaureate nursing education, mentoring would be an optimal methodology. The authors describe how a mentorship program combined with a professional role development course was integrated into a BSN nursing program. The evolution of the faculty-student mentorship program and the professional role development course is presented.