The Latrobe Smoking Support Service: A quantitative study of participants in a regional area.

Background and Aims: More than 70% of current smokers in Australia have a definite plan to stop smoking and around half of them try to quit every year. Latrobe Community Health Service (LCHS) was commissioned by Gippsland Primary Health Network to establish Latrobe Smoking Support Service (LSSS) to break down barriers to accessing services and increase support for smoking cessation. This research aims to assess the feasibility of an ongoing smoking cessation support service and determine the effect the LSSS has on client smoking behavior. Methods: Quantitative data were collected for the LSSS situated at LCHS during the period from September 2021 to March 2022. A new client survey, a returning client survey, and a 6-week follow-up survey were conducted by Clinic staff. The consent forms were obtained from the clients. A total of 117 clients attended the LSSS at least once, and a further 315 returning client sessions were conducted. The data analysis was undertaken by means of various descriptive and inferential statistical techniques, such as multiple linear regression analysis. Results: The research findings demonstrate the strong positive effect of the LSSS in helping clients to change their smoking behavior. Results of multiple regression analysis highlight the significant role of behavioral intervention strategies in the LSSS's success. A combination of both nicotine replacement therapy (NRT) and counseling was a key contributor to the project's success. Conclusion: This research proposed and tested the model of a smoking cessation support service that combines a comprehensive mix of services for smokers including free NRT, free counseling, and ongoing support of counselors or/and nurse practitioners.

The Green Transfer-Long-Term Results.

PURPOSE: The purpose of this study was to determine the long-term results of the Green transfer (flexor carpi ulnaris to extensor carpi radialis brevis) for patient-reported outcomes, wrist position, and range of motion. METHODS: We re-examined 13 patients from a previous prospective study involving surgery for hemiplegia that included a Green transfer. The average follow-up was 8 years with the range from 5 to 11 years. The wrist range of motion and the postoperative position of the wrists were measured. The surgical outcomes were measured via the Pediatric Orthopedic Data Collection Instrument, the Shriner's Hospital Upper Extremity Evaluation, Pediatric Quality of Life, and visual analog score for appearance from the patient and the parent. RESULTS: At this follow-up, only 7 of the 13 patients had a wrist position near neutral with the ability to flex and extend the wrist. Wrist range of motion was improved in four, decreased in four, and stayed the same in five patients. In contrast to these positional wrist results, statistically significant improvements were noted in several aspects of the Pediatric Orthopedic Data Collection Instrument, visual analog scores, and Shriner's Hospital Upper Extremity Evaluation scores. CONCLUSIONS: Long-term follow-up of the flexor carpi ulnaris to extensor carpi radialis brevis tendon transfer in hemiplegic patients reveals the results to be variable but favorable from a patient-reported outcome standpoint. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Development of [18F]DASA-10 for enhanced imaging of pyruvate kinase M2.

PURPOSE: The aim of this study was to develop a positron emission tomography (PET) radiotracer for measuring pyruvate kinase M2 (PKM2) with improved physicochemical and pharmacokinetic properties compared to [18F]DASA-23. EXPERIMENTAL DESIGN: First, we synthesized [18F]DASA-10 and tested its uptake and retention compared to [18F]DASA-23 in human and mouse glioma cell lines. We then confirmed the specificity of [18F]DASA-10 by transiently modulating the expression of PKM2 in DU145 and HeLa cells. Next, we determined [18F]DASA-10 pharmacokinetics in healthy nude mice using PET imaging and subsequently assessed the ability of [18F]DASA-10 versus [18F]DASA-23 to enable in vivo detection of intracranial gliomas in syngeneic C6 rat models of glioma. RESULTS: [18F]DASA-10 demonstrated excellent cellular uptake and retention with values significantly higher than [18F]DASA-23 in all cell lines and timepoints investigated. [18F]DASA-10 showed a 73 % and 65 % reduced uptake respectively in DU145 and HeLa cells treated with PKM2 siRNA as compared to control siRNA treated cells. [18F]DASA-10 showed favorable biodistribution and pharmacokinetic properties and a significantly improved tumor-to-brain ratio in rat C6 glioma models relative to [18F]DASA-23 (3.2 ± 0.8 versus 1.6 ± 0.3, p = 0.01). CONCLUSION: [18F]DASA-10 is a new PET radiotracer for molecular imaging of PKM2 with potential to overcome the prior limitations observed with [18F]DASA-23. [18F]DASA-10 shows promise for clinical translation to enable imaging of brain malignancies owing to its low background signal in the healthy brain.

Team Approach: The Care of Children with Hand and Upper Limb Differences.

¼ Pediatric hand and upper limb differences include a wide range of conditions that may be genetic, part of a syndrome, or arise from birth trauma or an unknown cause.¼ Because of the variety of conditions and complexity of care requiring professionals from multiple disciplines, the Pediatric Hand Team is similar in purpose to the coordinated multidisciplinary care provided by Craniofacial Panels for children with craniofacial anomalies. Pediatric hand surgeons are trained to lead and coordinate the care of children with these differences, and the Pediatric Hand Team includes occupational and/or certified hand therapists, child life specialists, geneticists and genetic counselors, prosthetists and orthotists, pediatric physical medicine and rehabilitation physicians, pediatric orthopaedic surgeons, pediatric anesthesiologists, and social workers and psychologists. The Team must also have access to pediatric imaging, including ultrasound and magnetic resonance imaging.¼ Treatment of hand differences may include observation, splinting/bracing, therapy, reconstructive surgery, or a combination of these, and indications vary with development, age, associated conditions, and child and family preference. Children who have challenges coping with the stigma of their difference may benefit from programs such as Hand Camp and the Lucky Fin Project.¼ Multiple online and print resources are available to support the Pediatric Hand Team and the child's family and other caregivers.¼ A well-coordinated team-based approach meets the physical and psychosocial needs of the child with hand and upper limb differences from birth to adulthood.

PET imaging of TREM1 identifies CNS-infiltrating myeloid cells in a mouse model of multiple sclerosis.

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system (CNS) that causes substantial morbidity and diminished quality of life. Evidence highlights the central role of myeloid lineage cells in the initiation and progression of MS. However, existing imaging strategies for detecting myeloid cells in the CNS cannot distinguish between beneficial and harmful immune responses. Thus, imaging strategies that specifically identify myeloid cells and their activation states are critical for MS disease staging and monitoring of therapeutic responses. We hypothesized that positron emission tomography (PET) imaging of triggering receptor expressed on myeloid cells 1 (TREM1) could be used to monitor deleterious innate immune responses and disease progression in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. We first validated TREM1 as a specific marker of proinflammatory, CNS-infiltrating, peripheral myeloid cells in mice with EAE. We show that the 64Cu-radiolabeled TREM1 antibody-based PET tracer monitored active disease with 14- to 17-fold higher sensitivity than translocator protein 18 kDa (TSPO)-PET imaging, the established approach for detecting neuroinflammation in vivo. We illustrate the therapeutic potential of attenuating TREM1 signaling both genetically and pharmacologically in the EAE mice and show that TREM1-PET imaging detected responses to an FDA-approved MS therapy with siponimod (BAF312) in these animals. Last, we observed TREM1+ cells in clinical brain biopsy samples from two treatment-naïve patients with MS but not in healthy control brain tissue. Thus, TREM1-PET imaging has potential for aiding in the diagnosis of MS and monitoring of therapeutic responses to drug treatment.

Clinical Radiosynthesis and Translation of [18F]OP-801: A Novel Radiotracer for Imaging Reactive Microglia and Macrophages.

Positron emission tomography (PET) is a powerful tool for studying neuroinflammatory diseases; however, current PET biomarkers of neuroinflammation possess significant limitations. We recently reported a promising dendrimer PET tracer ([18F]OP-801), which is selectively taken up by reactive microglia and macrophages. Here, we describe further important characterization of [18F]OP-801 in addition to optimization and validation of a two-step clinical radiosynthesis. [18F]OP-801 was found to be stable in human plasma for 90 min post incubation, and human dose estimates were calculated for 24 organs of interest; kidneys and urinary bladder wall without bladder voiding were identified as receiving the highest absorbed dose. Following optimization detailed herein, automated radiosynthesis and quality control (QC) analyses of [18F]OP-801 were performed in triplicate in suitable radiochemical yield (6.89 ± 2.23% decay corrected), specific activity (37.49 ± 15.49 GBq/mg), and radiochemical purity for clinical imaging. Importantly, imaging mice with tracer (prepared using optimized methods) 24 h following the intraperitoneal injection of liposaccharide resulted in the robust brain PET signal. Cumulatively, these data enable clinical translation of [18F]OP-801 for imaging reactive microglia and macrophages in humans. Data from three validation runs of the clinical manufacturing and QC were submitted to the Food and Drug Administration (FDA) as part of a Drug Master File (DMF). Subsequent FDA approval to proceed was obtained, and a phase 1/2 clinical trial (NCT05395624) for first-in-human imaging in healthy controls and patients with amyotrophic lateral sclerosis is underway.

Comparison of Different Methods of Measuring Finger Range of Motion via Telehealth.

PURPOSE: This study examined the accuracy and reliability of measuring total motion of the fingers via telehealth using the following three different methods: (1) goniometry, (2) visual estimation, and (3) electronic protractor. Measurements were compared with in-person measurement, which was assumed to be the reference standard. METHODS: Thirty clinicians measured finger range of motion from prerecorded videos of a mannequin hand with articulating fingers, which was posed in extension and flexion that simulated a telehealth visit, using a goniometer with results blinded to the clinician (blinded goniometry), visual estimation, and an electronic protractor, in random order. Total motion was calculated for each finger and for all four fingers in sum. The experience level, familiarity with measuring finger range of motion, and opinions of measurement difficulty were assessed. RESULTS: Measurement with the electronic protractor was the only method equivalent to the reference standard within 20°. Remote goniometer and visual estimation did not fall within the acceptable error margin of equivalence, and both underestimated total motion. Electronic protractor also had the highest interrater reliability (intraclass correlation [upper limit, lower limit], 0.95 [0.92, 0.95]); goniometry (intraclass correlation, 0.94 [0.91, 0.97]) was nearly identical, whereas visual estimation (intraclass correlation, 0.82 [0.74, 0.89]) was much lower. Clinicians' experience and familiarity with range of motion measurements had no relationship with the findings. Clinicians reported visual estimation as the most difficult (80%) and electronic protractor as the easiest method (73%). CONCLUSIONS: This study showed that traditional in-person forms of measurement underestimate finger range of motion via telehealth; a new computer-based method (ie, electronic protractor) was found to be more accurate. CLINICAL RELEVANCE: The use of an electronic protractor can be beneficial to clinicians measuring range of motion in patients virtually.

Is There a Role of Artificial Intelligence in Preclinical Imaging?

This review provides an overview of the current opportunities for integrating artificial intelligence methods into the field of preclinical imaging research in nuclear medicine. The growing demand for imaging agents and therapeutics that are adapted to specific tumor phenotypes can be excellently served by the evolving multiple capabilities of molecular imaging and theranostics. However, the increasing demand for rapid development of novel, specific radioligands with minimal side effects that excel in diagnostic imaging and achieve significant therapeutic effects requires a challenging preclinical pipeline: from target identification through chemical, physical, and biological development to the conduct of clinical trials, coupled with dosimetry and various pre, interim, and post-treatment staging images to create a translational feedback loop for evaluating the efficacy of diagnostic or therapeutic ligands. In virtually all areas of this pipeline, the use of artificial intelligence and in particular deep-learning systems such as neural networks could not only address the above-mentioned challenges, but also provide insights that would not have been possible without their use. In the future, we expect that not only the clinical aspects of nuclear medicine will be supported by artificial intelligence, but that there will also be a general shift toward artificial intelligence-assisted in silico research that will address the increasingly complex nature of identifying targets for cancer patients and developing radioligands.

Do Nails and Nubbins Matter? A Comparison of Symbrachydactyly and Transverse Deficiency Phenotypes.

PURPOSE: Transverse deficiency (TD) and symbrachydactyly may be difficult to distinguish due to shared phenotypes and a lack of pathognomonic features. The 2020 Oberg-Manske-Tonkin classification update modified these anomalies to include "with ectodermal elements" for symbrachydactyly and "without ectodermal elements" for TD as a defining differentiating characteristic. The purpose of this investigation was to characterize ectodermal elements and the level of deficiency and to examine whether ectodermal elements versus the level of deficiency was a greater determining factor for Congenital Upper Limb Differences (CoULD) surgeons making the diagnosis. METHODS: This was a retrospective review of 254 extremities from the CoULD registry with a diagnosis of symbrachydactyly or TD by pediatric hand surgeons. Ectodermal elements and the level of deficiency were characterized. A review of the registry radiographs and photographs was used to classify the diagnosis and compare it with the diagnosis given by the pediatric hand surgeons. The presence/absence of nubbins versus the level of deficiency as the determining factor to differentiate the pediatric hand surgeons' diagnosis of symbrachydactyly (with nubbins) versus TD (without nubbins) was analyzed. RESULTS: Based on radiographs and photographs of the 254 extremities, 66% had nubbins on the distal end of the limb; of the limbs with nubbins, nails were present on 51%. The level of deficiency was amelia/humeral (n = 9), <1/3 transverse forearm (n = 23), 1/3 to 2/3 transverse forearm (n = 27), 2/3 to full forearm TD (n = 38), and metacarpal/phalangeal (n = 103). The presence of nubbins was associated with a four times higher likelihood of a pediatric hand surgeon's diagnosis of symbrachydactyly. However, a distal deficiency is associated with a 20-times higher likelihood of a diagnosis of symbrachydactyly than a proximal deficiency. CONCLUSIONS: Although both the level of deficiency and ectodermal elements are important, the level of deficiency was a greater determining factor for a diagnosis of symbrachydactyly versus TD. Our results suggest that the level of deficiency and nubbins should both be described to help provide greater clarity in the diagnosis of symbrachydactyly versus TD. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic IV.

Reliability of the Masada Classification for Forearm Involvement in Patients With Hereditary Multiple Osteochondromas (HMO).

BACKGROUND: Classifications describing forearm lesions in patients with Hereditary Multiple Osteochondromatosis (HMO) have been used to recommend surgical intervention and stratify outcomes; however, there is no consensus on which classification offers greater reliability. The purpose of this study was to determine the reliability of the Masada classification and newer classifications among pediatric hand surgeons. METHODS: One hundred one patients with HMO between June 2014 and October 2019 were enrolled in the Congenital Upper Limb Differences (CoULD) Registry. Of those, 67 patients with 101 forearms were included. Four pediatric hand surgeons from the CoULD study group undertook an online evaluation. Each rater classified radiographs according to the Masada classification. Six weeks later, raters were asked to reclassify images according to the Masada, Gottschalk, and Jo classifications. Rater agreement for these classifications was assessed by estimating Fleiss kappa along with a 95% CI. RESULTS: Interrater agreement for Masada classification after the first reading was poor (κ=0.35; 95% CI=0.30-0.41) across all raters. Interrater agreement across the 4 raters decreased for the Masada classification from the first to the second reading (κ=0.35 vs 0.21; P <0.001). Intrarater agreement for the Masada classification ranged from 0.32 to 0.63 from the first to the second study reading. Gottschalk and Jo classifications yielded significantly better interrater agreement compared with Masada (κ=0.43 vs 0.21; P <0.001). Unclassifiable cases were highest in the Masada classification (34% to 44%) and lower in the Jo (17%) and Gottschalk (14%) classifications. CONCLUSION: Despite wide use, the Masada classification was found to have low reliability when classifying forearm deformities in HMO. Gottschalk offered more options for location, yet lacked deformity description including radial head dislocation. Jo classification offered more locations than Masada and incorporated radial head dislocation in some patterns. Based on the shortcomings in all 3 classification systems, the development of a more inclusive and reliable classification is warranted. LEVEL OF EVIDENCE: Level II; Diagnostic.

Long-Term Outcomes of Biceps Rerouting for Flexible Supination Contractures in Children With Brachial Plexus Birth Injuries.

PURPOSE: Forearm supination contractures occur in 7% of children with brachial plexus birth injuries (BPBI). Biceps rerouting is proposed when pronation has deteriorated but is passively correctable to at least 0° (neutral). The purpose of this investigation was to evaluate long-term outcomes of biceps rerouting for this indication, including magnitude and maintenance of correction, complications, and subsequent osteotomy. METHODS: We conducted a retrospective review of all children with BPBI and forearm supination contractures treated with biceps rerouting alone, for the above indications, from 1993 to 2017 with at least 2 years follow-up. Demographic information, BPBI characteristics, surgical details, and ranges of motion were obtained from medical records. Pre- and postoperative active pronation (AP) and supination (AS), elbow flexion contracture, and arc of forearm rotation (Arc) were analyzed using linear mixed-effect models. RESULTS: Twenty-five children (13 females; 13 left forearms; 15 global BPBI) underwent biceps rerouting at age 7 ± 3 years and were followed for 6 ± 3 years. Before surgery, the mean AP and AS were 6° ± 29° and 62° ± 27°, respectively. At the final follow-up, the mean AP, AS, and Arc were 39° ± 36°, 18° ± 34°, and 57° ± 42°, respectively. AP was significantly improved and AS was significantly decreased by 2 years after surgery and at the final follow-up. Neither Arc nor elbow flexion contracture changed significantly. Two of 25 (8%) children underwent subsequent forearm osteotomy. CONCLUSIONS: Biceps rerouting in children with BPBI improves the forearm position when pronation is deteriorating by shifting the arc from supination to pronation without decreasing the arc of motion or worsening elbow flexion contractures. There is a low risk of complications and a limited need for subsequent forearm osteotomy. These results are maintained over time. When performed before passive pronation is reduced beyond neutral, this procedure may prevent severe supination contractures and reduce the need for forearm osteotomy. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Multimodal imaging of capsid and cargo reveals differential brain targeting and liver detargeting of systemically-administered AAVs.

The development of gene delivery vehicles with high organ specificity when administered systemically is a critical goal for gene therapy. We combine optical and positron emission tomography (PET) imaging of 1) reporter genes and 2) capsid tags to assess the temporal and spatial distribution and transduction of adeno-associated viruses (AAVs). AAV9 and two engineered AAV vectors (PHP.eB and CAP-B10) that are noteworthy for maximizing blood-brain barrier transport were compared. CAP-B10 shares a modification in the 588 loop with PHP.eB, but also has a modification in the 455 loop, added with the goal of reducing off-target transduction. PET and optical imaging revealed that the additional modifications retained brain receptor affinity. In the liver, the accumulation of AAV9 and the engineered AAV capsids was similar (∼15% of the injected dose per cc and not significantly different between capsids at 21 h). However, the engineered capsids were primarily internalized by Kupffer cells rather than hepatocytes, and liver transduction was greatly reduced. PET reporter gene imaging after engineered AAV systemic injection provided a non-invasive method to monitor AAV-mediated protein expression over time. Through comparison with capsid tagging, differences between brain localization and transduction were revealed. In summary, AAV capsids bearing imaging tags and reporter gene payloads create a unique and powerful platform to assay the pharmacokinetics, cellular specificity and protein expression kinetics of AAV vectors in vivo, a key enabler for the field of gene therapy.

Clinical Manifestations of Constriction Band Syndrome.

BACKGROUND: Constriction band syndrome (CBS) is a congenital limb anomaly with varying presentation. We sought to characterize the clinical manifestations of CBS by analyzing a large cohort of patients. Our secondary aim was to evaluate potential risk factors for CBS. METHODS: We retrospectively reviewed the records for all patients with CBS who had presented to our tertiary medical center between 1998 and 2018. Examination by a pediatric orthopaedic surgeon and the presence of pathognomonic features were inclusion criteria. Clinical notes, photographs, and radiographs were reviewed to determine the pattern of limb involvement and associated conditions. Demographic data were compared with population averages to assess for possible risk factors. RESULTS: One hundred and twenty-eight children were included. The most prevalent feature was constriction bands (96%), followed by limb or digit amputations (88%) and syndactyly/acrosyndactyly (69%). Children without constriction bands presented with either acrosyndactyly or growth of an osseous spike from a congenital diaphyseal limb or digit amputation. There was a strong predilection for involvement of central digits of the hands and feet, with sparing of the thumb/great toe and small finger/toe. The average number of involved limbs per child was 2.6; 23% of the children had involvement of only 1 limb. Children with at least 1 additional diagnosis had more limbs affected by CBS than those who were otherwise healthy (2 limbs [interquartile range (IQR), 1-3 limbs] versus 3 limbs [IQR, 2-4 limbs]; p = 0.006), suggesting a more severe phenotype. Children with more limbs involved underwent more surgical procedures (p < 0.001). CBS was associated with gestational trauma, prematurity, low birth weight, young and old maternal age, and higher social deprivation. CONCLUSIONS: Children with CBS can be categorized as having either mild or extensive involvement based on the number of involved limbs and associated conditions. Future investigation of prenatal risk factors is necessary to further elucidate the etiology of this heterogenous condition. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

ICOS immunoPET enables visualization of activated T cells and early diagnosis of murine acute gastrointestinal GvHD.

Allogeneic hematopoietic cell transplantation (HCT) is a well-established and potentially curative treatment for a broad range of hematological diseases, bone marrow failure states, and genetic disorders. Acute graft-versus-host disease (GvHD), mediated by donor T cells attacking host tissues, still represents a major cause of morbidity and mortality following allogeneic HCT. Current approaches to diagnosis of gastrointestinal acute GvHD rely on clinical and pathological criteria that manifest at late stages of disease. New strategies allowing for GvHD prediction and diagnosis, prior to symptom onset, are urgently needed. Noninvasive antibody-based positron emission tomography (PET) (immunoPET) imaging of T-cell activation post-allogeneic HCT is a promising strategy toward this goal. In this work, we identified inducible T-cell costimulator (ICOS) as a potential immunoPET target for imaging activated T cells during GvHD. We demonstrate that the use of the Zirconium-89-deferoxamine-ICOS monoclonal antibody PET tracer allows in vivo visualization of donor T-cell activation in target tissues, namely the intestinal tract, in a murine model of acute GvHD. Importantly, we demonstrate that the Zirconium-89-deferoxamine-ICOS monoclonal antibody PET tracer does not affect GvHD pathogenesis or the graft-versus-tumor (GvT) effect of the transplant procedure. Our data identify ICOS immunoPET as a promising strategy for early GvHD diagnosis prior to the appearance of clinical symptoms.

Porcine Epidemic Diarrhea: Causative Agent, Epidemiology, Clinical Characteristics, and Treatment Strategy Targeting Main Protease.

AIMS: This aimed to study the causative agent, epidemiology, clinical characteristics, and treatment strategy targeting the main protease in porcine epidemic diarrhea. BACKGROUND: Porcine epidemic diarrhea (PED) is a contagious intestinal viral infection causing severe diarrhea, vomiting, and dehydration in pigs. High rates of mortalities and severe morbidities, approaching 100%, are reported in piglets infected with PEDV. In recent years, PED has been observed to influence the swine-farming nations in Europe, Asia, the USA, South Korea, and Canada. The PED virus (PEDV) transmission takes place through a faecal-oral route. OBJECTIVE: The objective is to review the characteristics of PEDV and its role in the disease. In addition, we aim to outline some possible methods to combat PED infection, including targeting the main protease of coronavirus and their future perspectives. METHODS: This study is a review of literature on the PED virus. RESULTS: Apart from symptomatic treatment and supportive care, there is no available specific treatment for PEDV. Appropriate disinfectants and cleaning are pivotal for the control of PEDV. To date, apart from anti-PEDV inhibitors, there are no specific drugs available commercially to treat the disease. Therefore, 3C-like protease (3CLpro) in PEDV that has highly conserved structure and catalytic mechanism serves as an alluring drug as it plays a vital role during viral polyprotein processing at the time of infection. CONCLUSION: A well synchronized and collective effort of scientists, swine veterinarians, pork industry experts, and associated authorities is essential for the accomplishment of proper execution of these required measures.

Tracking Innate Immune Activation in a Mouse Model of Parkinson's Disease Using TREM1 and TSPO PET Tracers.

Parkinson's disease (PD) is associated with aberrant innate immune responses, including microglial activation and infiltration of peripheral myeloid cells into the central nervous system (CNS). Methods to investigate innate immune activation in PD are limited and have not yet elucidated key interactions between neuroinflammation and peripheral inflammation. Translocator protein 18 kDa (TSPO) PET is a widely evaluated imaging approach for studying activated microglia and peripheral myeloid lineage cells in vivo but has yet to be fully explored in PD. Here, we investigate the utility of TSPO PET in addition to PET imaging of triggering receptor expressed on myeloid cells 1 (TREM1)-a novel biomarker of proinflammatory innate immune cells-for detecting innate immune responses in the 6-hydroxydopamine mouse model of dopaminergic neuron degeneration. Methods: C57/BL6J and TREM1 knockout mice were stereotactically injected with 6-hydroxydopamine in the left striatum; control mice were injected with saline. At day 7 or 14 after surgery, mice were administered 18F-GE-180, 64Cu-TREM1 monoclonal antibody (mAb), or 64Cu-isotype control mAb and imaged by PET/CT. Ex vivo autoradiography was performed to obtain high-resolution images of tracer binding within the brain. Immunohistochemistry was conducted to verify myeloid cell activation and dopaminergic cell death, and quantitative polymerase chain reaction and flow cytometry were completed to assess levels of target in the brain. Results: PET/CT images of both tracers showed elevated signal within the striatum of 6-hydroxydopamine-injected mice compared with those injected with saline. Autoradiography afforded higher-resolution brain images and revealed significant TSPO and TREM1 tracer binding within the ipsilateral striatum of 6-hydroxydopamine mice compared with saline mice at both 7 and 14 d after toxin. Interestingly, 18F-GE-180 enabled detection of inflammation in the brain and peripheral tissues (blood and spleen) of 6-hydroxydopamine mice, whereas 64Cu-TREM1 mAb appeared to be more sensitive and specific for detecting neuroinflammation, in particular infiltrating myeloid cells, in these mice, as demonstrated by flow cytometry findings and higher tracer binding signal-to-background ratios in brain. Conclusion: TSPO and TREM1 PET tracers are promising tools for investigating different cell types involved in innate immune activation in the context of dopaminergic neurodegeneration, thus warranting further investigation in other PD rodent models and human postmortem tissue to assess their clinical potential.

A Clinical PET Imaging Tracer ([18F]DASA-23) to Monitor Pyruvate Kinase M2-Induced Glycolytic Reprogramming in Glioblastoma.

PURPOSE: Pyruvate kinase M2 (PKM2) catalyzes the final step in glycolysis, a key process of cancer metabolism. PKM2 is preferentially expressed by glioblastoma (GBM) cells with minimal expression in healthy brain. We describe the development, validation, and translation of a novel PET tracer to study PKM2 in GBM. We evaluated 1-((2-fluoro-6-[18F]fluorophenyl)sulfonyl)-4-((4-methoxyphenyl)sulfonyl)piperazine ([18F]DASA-23) in cell culture, mouse models of GBM, healthy human volunteers, and patients with GBM. EXPERIMENTAL DESIGN: [18F]DASA-23 was synthesized with a molar activity of 100.47 ± 29.58 GBq/µmol and radiochemical purity >95%. We performed initial testing of [18F]DASA-23 in GBM cell culture and human GBM xenografts implanted orthotopically into mice. Next, we produced [18F]DASA-23 under FDA oversight, and evaluated it in healthy volunteers and a pilot cohort of patients with glioma. RESULTS: In mouse imaging studies, [18F]DASA-23 clearly delineated the U87 GBM from surrounding healthy brain tissue and had a tumor-to-brain ratio of 3.6 ± 0.5. In human volunteers, [18F]DASA-23 crossed the intact blood-brain barrier and was rapidly cleared. In patients with GBM, [18F]DASA-23 successfully outlined tumors visible on contrast-enhanced MRI. The uptake of [18F]DASA-23 was markedly elevated in GBMs compared with normal brain, and it identified a metabolic nonresponder within 1 week of treatment initiation. CONCLUSIONS: We developed and translated [18F]DASA-23 as a new tracer that demonstrated the visualization of aberrantly expressed PKM2 for the first time in human subjects. These results warrant further clinical evaluation of [18F]DASA-23 to assess its utility for imaging therapy-induced normalization of aberrant cancer metabolism.

Whole-body PET Imaging of T-cell Response to Glioblastoma.

PURPOSE: Immunotherapy is a promising approach for many oncological malignancies, including glioblastoma, however, there are currently no available tools or biomarkers to accurately assess whole-body immune responses in patients with glioblastoma treated with immunotherapy. Here, the utility of OX40, a costimulatory molecule mainly expressed on activated effector T cells known to play an important role in eliminating cancer cells, was evaluated as a PET imaging biomarker to quantify and track response to immunotherapy. EXPERIMENTAL DESIGN: A subcutaneous vaccination approach of CpG oligodeoxynucleotide, OX40 mAb, and tumor lysate at a remote site in a murine orthotopic glioma model was developed to induce activation of T cells distantly while monitoring their distribution in stimulated lymphoid organs with respect to observed therapeutic effects. To detect OX40-positive T cells, we utilized our in-house-developed 89Zr-DFO-OX40 mAb and in vivo PET/CT imaging. RESULTS: ImmunoPET with 89Zr-DFO-OX40 mAb revealed strong OX40-positive responses with high specificity, not only in the nearest lymph node from vaccinated area (mean, 20.8%ID/cc) but also in the spleen (16.7%ID/cc) and the tumor draining lymph node (11.4%ID/cc). When the tumor was small (<106 p/sec/cm2/sr in bioluminescence imaging), a high number of responders and percentage shrinkage in tumor signal was indicated after only a single cycle of vaccination. CONCLUSIONS: The results highlight the promise of clinically translating cancer vaccination as a potential glioma therapy, as well as the benefits of monitoring efficacy of these treatments using immunoPET imaging of T-cell activation.