Publications by authors named "Tony Huynh"

64 Publications

Autoregulation of insulin receptor signaling through MFGE8 and the αvβ5 integrin.

Proc Natl Acad Sci U S A 2021 May;118(18)

Cardiovascular Research Institute, University of California, San Francisco, CA 94158;

The role of integrins, in particular αv integrins, in regulating insulin resistance is incompletely understood. We have previously shown that the αvβ5 integrin ligand milk fat globule epidermal growth factor like 8 (MFGE8) regulates cellular uptake of fatty acids. In this work, we evaluated the impact of MFGE8 on glucose homeostasis. We show that acute blockade of the MFGE8/β5 pathway enhances while acute augmentation dampens insulin-stimulated glucose uptake. Moreover, we find that insulin itself induces cell-surface enrichment of MFGE8 in skeletal muscle, which then promotes interaction between the αvβ5 integrin and the insulin receptor leading to dampening of skeletal-muscle insulin receptor signaling. Blockade of the MFGE8/β5 pathway also enhances hepatic insulin sensitivity. Our work identifies an autoregulatory mechanism by which insulin-stimulated signaling through its cognate receptor is terminated through up-regulation of MFGE8 and its consequent interaction with the αvβ5 integrin, thereby establishing a pathway that can potentially be targeted to improve insulin sensitivity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2102171118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8106306PMC
May 2021

Longitudinal imaging of T-cells and inflammatory demyelination in a preclinical model of multiple sclerosis using F-FAraG PET and MRI.

J Nucl Med 2021 Apr 9. Epub 2021 Apr 9.

University of California San Francisco, United States.

Lymphocytes and innate immune cells are key drivers of multiple sclerosis (MS) and are the main target of MS disease modifying therapies (DMT). Ex vivo analyses of MS lesions have revealed cellular heterogeneity and variable T-cell levels, which may have important implication for patient stratification and choice of DMT. Although magnetic resonance imaging (MRI) has proven valuable to monitor DMT efficacy, its lack of specificity for cellular subtypes highlights the need for complementary methods to improve lesion characterization. Here, we evaluated the potential of 2'-deoxy-2'-[F]fluoro-9-β-D-arabinofuranosylguanine (F-FAraG) PET imaging to non-invasively assess infiltrating T-cells and to provide, in combination with MRI, a novel tool to determine lesion types. We used a novel MS mouse model that combines cuprizone and experimental autoimmune encephalomyelitis (EAE) to reproducibly induce two brain inflammatory lesion types, differentiated by their T-cell content. F-FAraG PET imaging, T2-weighted MRI, and T1-weighted contrast-enhanced MRI were performed prior to disease induction, during demyelination with high levels of innate immune cells, and following T-cell infiltration. Fingolimod immunotherapy was used to evaluate the ability of PET and MRI to detect therapy response. Ex vivo immunofluorescence analyses for T-cells, microglia/macrophages, myelin and blood brain barrier (BBB) integrity were performed to validate the in vivo findings. F-FAraG signal was significantly increased in brain and spinal cord at the time point of T-cell infiltration. F-FAraG signal from white matter (corpus callosum), and grey matter (cortex, hippocampus) further correlated with T-cell density. T2-weighted MRI detected white matter lesions independently of T-cells. T1-weighted contrast-enhanced MRI indicated BBB disruption at the time point of T-cell infiltration. Fingolimod treatment prevented motor deficits and decreased T-cell and microglia/macrophage levels. In agreement, F-FAraG signal was decreased in brain and spinal cord of Fingolimod-treated mice, T1-weighted contrast-enhanced MRI revealed intact BBB, while T2-weighted MRI remained unchanged. The combination of MRI and F-FAraG PET enables detection of inflammatory demyelination and T-cell infiltration in a MS mouse model, providing a new way to evaluate lesion heterogeneity during disease progression and following DMT. Upon clinical translation, these methods hold great potential for patient stratification, monitoring MS progression and therapy responses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2967/jnumed.120.259325DOI Listing
April 2021

Role of D(T)PACE-based regimens as treatment of multiple myeloma with extramedullary relapse or refractory disease.

Leuk Lymphoma 2021 Apr 1:1-7. Epub 2021 Apr 1.

Service d'Hématologie et thérapie cellulaire, Hôpital Saint-Antoine, AP-HP, Paris, France.

In multiple myeloma, atypical forms with extramedullary involvement exhibit poor survival. The poly-chemotherapeutic regimen D(T)-PACE has shown high activity in relapsed or refractory multiple myeloma. In this large monocentric retrospective study, we addressed the activity of D(T)-PACE-based regimens in 43 heavily pretreated patients with relapsed/refractory multiple myeloma and extramedullary disease.Median age at initiation was 57 years. Four patients had a t(4;14) translocation, 3 had a t(11;14) translocation and 7 had a del(17p). Extramedullary sites were mostly the skin (15 patients), central nervous system (10 patients), and thorax or abdomen (10 patients each). Overall response was achieved in 25 (58%) patients, including 6 (14%) with a complete response. Median progression-free survival was 5.0 months. Median overall survival was 9.0 months. Fourteen patients subsequently underwent stem-cell transplantation. Cytogenetics had no impact on response rate, overall survival and progression-free survival.In the era of several new immunotherapies, D(T)-PACE-based regimens still remain a useful treatment option for a selected group of heavily pretreated myeloma patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/10428194.2021.1907373DOI Listing
April 2021

Flip Distances Between Graph Orientations.

Algorithmica 2021 27;83(1):116-143. Epub 2020 Jul 27.

TU Graz, Graz, Austria.

Flip graphs are a ubiquitous class of graphs, which encode relations on a set of combinatorial objects by elementary, local changes. Skeletons of associahedra, for instance, are the graphs induced by quadrilateral flips in triangulations of a convex polygon. For some definition of a flip graph, a natural computational problem to consider is the flip distance: Given two objects, what is the minimum number of flips needed to transform one into the other? We consider flip graphs on orientations of simple graphs, where flips consist of reversing the direction of some edges. More precisely, we consider so-called -orientations of a graph , in which every vertex has a specified outdegree , and a flip consists of reversing all edges of a directed cycle. We prove that deciding whether the flip distance between two -orientations of a planar graph is at most two is NP-complete. This also holds in the special case of perfect matchings, where flips involve alternating cycles. This problem amounts to finding geodesics on the common base polytope of two partition matroids, or, alternatively, on an alcoved polytope. It therefore provides an interesting example of a flip distance question that is computationally intractable despite having a natural interpretation as a geodesic on a nicely structured combinatorial polytope. We also consider the dual question of the flip distance between graph orientations in which every cycle has a specified number of forward edges, and a flip is the reversal of all edges in a minimal directed cut. In general, the problem remains hard. However, if we restrict to flips that only change sinks into sources, or vice-versa, then the problem can be solved in polynomial time. Here we exploit the fact that the flip graph is the cover graph of a distributive lattice. This generalizes a recent result from Zhang et al. (Acta Math Sin Engl Ser 35(4):569-576, 2019).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00453-020-00751-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7846516PMC
July 2020

APR-246 induces early cell death by ferroptosis in acute myeloid leukemia.

Haematologica 2021 Jan 7. Epub 2021 Jan 7.

Université de Paris, Institut Cochin, CNRS UMR8104, INSERM U1016, Paris, France; Assistance Publique-Hôpitaux de Paris. Centre-Université de Paris, Service d'Hématologie clinique, Hôpital Cochin, Paris.

APR-246 is a promising new therapeutic agent that targets p53 mutated proteins in myelodysplastic syndromes and in acute myeloid leukemia. APR-246 reactivates the transcriptional activity of p53 mutants by facilitating their binding to DNA target sites. Recent studies in solid cancers have found that APR-246 can also induce p53-independent cell death. In this study, we demonstrate that AML cell death occurring early after APR-246 exposure is suppressed by iron chelators, lipophilic antioxidants and inhibitors of lipid peroxidation, and correlates with the accumulation of markers of lipid peroxidation, thus fulfilling the definition of ferroptosis, a recently described cell death process. The capacity of AML cells to detoxify lipid peroxides by increasing their cystine uptake to maintain major antioxidant molecule glutathione biosynthesis after exposure to APR-246 may be a key determinant of sensitivity to this compound. The association of APR-246 with induction of ferroptosis (either by pharmacological compounds, or genetic inactivation of SLC7A11 or GPX4) had a synergistic effect on the promotion of cell death, both in vivo and ex vivo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3324/haematol.2020.259531DOI Listing
January 2021

Pre-analytical mysteries: A case of severe hypervitaminosis D and mild hypercalcaemia.

Biochem Med (Zagreb) 2021 Feb 15;31(1):011001. Epub 2020 Dec 15.

Department of Endocrinology and Diabetes, Mater Hospital, South Brisbane QLD, Australia.

We describe a case of severe hypervitaminosis D and mild hypercalcaemia in a 68-year-old woman who presented with fatigue and weight loss. Her 25-hydroxy vitamin D (25OHD) was > 400 nmol/L (50-150) and corrected serum calcium was 2.83 mmol/L (2.1-2.6). Her intact parathyroid hormone (PTH) was 4.9 pmol/L (2.0-9.5). Further investigation revealed an IgM kappa paraprotein, and a bone marrow aspirate confirmed a diagnosis of lymphoplasmacytic lymphoma/Waldenstrom's macroglobulinemia (LPL/WM). As the vitamin D level was discordant with the patient's other results and presentation, the presence of an assay interferent was suspected. A 1-in-2 dilution of the sample returned a 25OHD result of 84 nmol/L in keeping with the presence of an interferent. Testing for rheumatoid factor was negative. The sample was treated with an antibody blocking reagent (Scantibodies) and results were not consistent with heterophile antibody interference. The sample was then analysed using liquid chromatography tandem mass spectrometry (LC-MS/MS), which returned a 25OHD result of 82 nmol/L. Testing on an alternative immunoassay platform produced a 25OHD result of 75 nmol/L. Reapeted testing on the original platform following reduction of the monoclonal paraprotein with chemotherapy, returned a result of 64 nmol/L. The patient's mild hypercalcaemia persisted following resolution of the monoclonal paraprotein, in keeping with a diagnosis of primary hyperparathyroidism. This case highlights the potential for paraproteins to cause assay interference, and the importance of considering interference when results are incongruous with the clinical presentation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.11613/BM.2021.011001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7745154PMC
February 2021

Biological Distribution and Metabolic Profiles of Carbon-11 and Fluorine-18 Tracers of VX- and Sarin-Analogs in Sprague-Dawley Rats.

Chem Res Toxicol 2021 Jan 29;34(1):63-69. Epub 2020 Dec 29.

Department of Radiology and Biomedical Imaging, University of California at San Francisco, San Francisco, California 94143, United States.

Organophosphorus esters (OPs) were originally developed as pesticides but were repurposed as easily manufactured, inexpensive, and highly toxic chemical warfare agents. Acute OP toxicity is primarily due to inhibition of acetylcholinesterase (AChE), an enzyme in the central and peripheral nervous system. OP inhibition of AChE can be reversed using oxime reactivators but many show poor CNS penetration, indicating a need for new clinically viable reactivators. However, challenges exist on how to best measure restored AChE activity in vivo and assess the reactivating agent efficacy. This work reports the development of molecular imaging tools using radiolabeled OP analog tracers that are less toxic to handle in the laboratory, yet inhibit AChE in a similar fashion to the actual OPs. Carbon-11 and fluorine-18 radiolabeled analog tracers of VX and sarin OP agents were prepared. Following intravenous injection in normal Sprague-Dawley rats ( = 3-4/tracer), the tracers were evaluated and compared using noninvasive microPET/CT imaging, biodistribution assay, and arterial blood analyses. All showed rapid uptake and stable retention in brain, heart, liver, and kidney tissues determined by imaging and biodistribution. Lung uptake of the sarin analog tracers was elevated, 2-fold and 4-fold higher uptake at 5 and 30 min, respectively, compared to that for the VX analog tracers. All tracers rapidly bound to red blood cells (RBC) and blood proteins as measured in the biodistribution and arterial blood samples. Analysis of the plasma soluble activity (nonprotein/cell bound activity) showed only 1-6% parent tracer and 88-95% of the activity in the combined solid fractions (RBC and protein bound) as early as 0.5 min post injection. Multivariate analysis of tracer production yield, molar activity, brain uptake, brain area under the curve over 0-15 min, and the amount of parent tracer in the plasma at 5 min revealed the [F]VX analog tracer had the most favorable values for each metric. This tracer was considered the more optimal tracer relative to the other tracers studied and suitable for future in vivo OP exposure and reactivation studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.chemrestox.0c00237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7818893PMC
January 2021

Clinical and Laboratory Aspects of Insulin Autoantibody-Mediated Glycaemic Dysregulation and Hyperinsulinaemic Hypoglycaemia: Insulin Autoimmune Syndrome and Exogenous Insulin Antibody Syndrome.

Authors:
Tony Huynh

Clin Biochem Rev 2020 Dec;41(3):93-102

Department of Endocrinology and Diabetes, Queensland Children's Hospital, South Brisbane 4101, Australia.

Autoimmune glycaemic dysregulation and hyperinsulinaemic hypoglycaemia mediated by insulin autoantibodies is an increasingly recognised but controversial phenomenon described in both exogenous insulin naïve (insulin autoimmune syndrome) and exposed (exogenous insulin antibody syndrome) individuals. There has been a significant proliferation of case reports, clinical studies and reviews in the medical literature in recent years which have collectively highlighted the discrepancy between experts in the field with regard to the nomenclature, definition, proposed pathophysiology, as well as the clinical and biochemical diagnostic criteria associated with the condition. The essential characteristics of the condition are glycaemic dysregulation manifesting as episodes of hyperglycaemia and unpredictable hyperinsulinaemic hypoglycaemia associated with high titres of endogenous antibodies to insulin. Although the hypoglycaemia is often life-threatening and initiation of targeted therapies critical, the diagnosis is often delayed and attributable to various factors including: the fact that existence of the condition is not universally accepted; the need to exclude surreptitious causes of hypoglycaemia; the diverse and often complex nature of the glycaemic dysregulation; and the challenge of diagnostic confirmation. Once confirmed, the available therapeutic options are expansive and the reported responses to these therapies have been variable. This review will focus on our evolving understanding, and the associated diagnostic challenges - both clinical and laboratory - of this complex condition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.33176/AACB-20-00008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7731936PMC
December 2020

Molecular Imaging of Prostate Cancer Targeting CD46 Using ImmunoPET.

Clin Cancer Res 2021 Mar 8;27(5):1305-1315. Epub 2020 Dec 8.

Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, Virginia.

Purpose: We recently identified CD46 as a novel therapeutic target in prostate cancer. In this study, we developed a CD46-targeted PET radiopharmaceutical, [Zr]DFO-YS5, and evaluated its performance for immunoPET imaging in murine prostate cancer models.

Experimental Design: [Zr]DFO-YS5 was prepared and its binding affinity for CD46 was measured. ImmunoPET imaging was conducted in male athymic nu/nu mice bearing DU145 [AR, CD46, prostate-specific membrane antigen-negative (PSMA)] or 22Rv1 (AR, CD46, PSMA) tumors, and in NOD/SCID gamma mice bearing patient-derived adenocarcinoma xenograft, LTL-331, and neuroendocrine prostate cancers, LTL-331R and LTL-545.

Results: [Zr]DFO-YS5 binds specifically to the CD46-positive human prostate cancer DU145 and 22Rv1 xenografts. In biodistribution studies, the tumor uptake of [Zr]DFO-YS5 was 13.3 ± 3.9 and 11.2 ± 2.5 %ID/g, respectively, in DU145 and 22Rv1 xenografts, 4 days postinjection. Notably, [Zr]DFO-YS5 demonstrated specific uptake in the PSMA- and AR-negative DU145 model. [Zr]DFO-YS5 also showed uptake in the patient-derived LTL-331 and -331R models, with particularly high uptake in the LTL-545 neuroendocrine prostate cancer tumors (18.8 ± 5.3, 12.5 ± 1.8, and 32 ± 5.3 %ID/g in LTL-331, LTL-331R, and LTL-545, respectively, at 4 days postinjection).

Conclusions: [Zr]DFO-YS5 is an excellent PET imaging agent across a panel of prostate cancer models, including in both adenocarcinoma and neuroendocrine prostate cancer, both cell line- and patient-derived xenografts, and both PSMA-positive and -negative tumors. It demonstrates potential for clinical translation as an imaging agent, theranostic platform, and companion biomarker in prostate cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/1078-0432.CCR-20-3310DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7925362PMC
March 2021

F-AraG PET for CD8 Profiling of Tumors and Assessment of Immunomodulation by Chemotherapy.

J Nucl Med 2021 Jun 6;62(6):802-807. Epub 2020 Nov 6.

CellSight Technologies Incorporated, San Francisco, California; and.

Most clinical trials exploring various combinations of chemo- and immunotherapy rely on serial biopsy to provide information on immune response. The aim of this study was to assess the value of F-arabinosyl guanine (F-AraG) as a noninvasive tool that profiles tumors on the basis of the key player in adaptive antitumor response, CD8+ cells, and evaluates the immunomodulatory effects of chemotherapy. To evaluate the ability of F-AraG to report on the presence of CD8+ cells within the tumor microenvironment, we imaged a panel of syngeneic tumor models (MC38, CT26, LLC, A9F1, 4T1, and B16F10) and correlated the signal intensity with the number of lymphocytes found in the tumors. The capacity of F-AraG to detect immunomodulatory effects of chemotherapy was determined by longitudinal imaging of tumor-bearing mice (MC38 and A9F1) undergoing 2 types of chemotherapy: oxaliplatin/cyclophosphamide, shown to induce immunogenic cell death, and paclitaxel/carboplatin, reported to cause immunogenically silent tumor cell death. In the tumor panel, F-AraG revealed strikingly different uptake patterns resembling cancer-immune phenotypes observed in the clinic. A statistically significant correlation was found between the F-AraG signal and the number of PD-1-positive CD8+ cells isolated from the tumors ( = 0.528, < 0.0001). In the MC38 model, paclitaxel/carboplatin did not result in an appreciable change in signal after therapy (1.69 ± 0.25 vs. 1.50 ± 0.33 percentage injected dose per gram), but oxaliplatin/cyclophosphamide treatment led to close to a 2.4-fold higher F-AraG signal (1.20 ± 0.31 vs. 2.84 ± 0.93 percentage injected dose per gram). The statistically significant increase in signal after oxaliplatin/cyclophosphamide was also observed in the A9F1 model (0.95 ± 0.36 vs. 1.99 ± 0.54 percentage injected dose per gram). The ability of F-AraG PET to assess the location and function of CD8+ cells, as well immune activity within tumors after immune priming therapy, warrants further investigation into its utility for patient selection, evaluation of optimal time to deliver immunotherapies, and assessment of combinatorial therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2967/jnumed.120.249078DOI Listing
June 2021

Tibial Nerve Dysfunction Associated With Operatively Treated Talar Neck Fractures.

J Orthop Trauma 2020 09;34(9):488-491

Department of Orthopaedic Surgery, Emory University School of Medicine, Atlanta, GA; and.

Objective: To investigate the presence of tibial nerve dysfunction (TND) in operatively treated talar neck fractures.

Design: Retrospective chart review.

Setting: Urban Level-1 trauma center.

Patients: Sixty-four patients for a total of 65 talar neck fractures treated with open reduction and internal fixation between January 1, 2014, and May 1, 2018.

Main Outcome Measures: Incidence of TND.

Results: Evidence of TND was documented in 20 of 65 cases (30.8%) of talar neck fractures. There were no cases of TND associated with Hawkins I fractures, but TND was found in 7 of 32 Hawkins II fractures (21.9%), 10 of 24 Hawkins III fractures (41.7%), and 3 of 5 Hawkins IV fractures (60%). TND was reported in 11 of 19 open talar neck fractures (57.9%) (P = 0.002). TND was associated with tibiotalar dislocation (P = 0.017) but not subtalar dislocation (P = 0.17). TND did not occur in the absence of subtalar subluxation/dislocation. Of 18, a total of 6 (33.3%) reported partial recovery, and 6 (33.3%) reported full recovery within 6 months of the initial injury. By 12 months, of the 18, 8 (44.4%) reported partial recovery and 7 (38.9%) reported full recovery.

Conclusion: The tibial nerve and its distal branches are at risk of injury in the setting of displaced talar neck fracture, tibiotalar subluxation/dislocation, and open talar neck fracture with increasing risk among those with a higher Hawkins grade.

Level Of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/BOT.0000000000001777DOI Listing
September 2020

Challenges of managing congenital hyperinsulinism in remote Aboriginal Australian communities.

J Paediatr Child Health 2021 May 18;57(5):727-731. Epub 2020 Aug 18.

Department of Endocrinology and Diabetes, Queensland Children's Hospital, Brisbane, Queensland, Australia.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jpc.14984DOI Listing
May 2021

A Rare and Unusual Cause of Unilateral Ureteric Obstruction in a Child.

Clin Chem 2020 08;66(8):1006-1009

Department of Endocrinology and Diabetes, Queensland Children's Hospital, South Brisbane, QLD, Australia.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/clinchem/hvaa059DOI Listing
August 2020

Pairing MCL-1 inhibition with venetoclax improves therapeutic efficiency of BH3-mimetics in AML.

Eur J Haematol 2020 Nov 4;105(5):588-596. Epub 2020 Aug 4.

Institut Cochin, CNRS UMR8104, INSERM U1016, Université de Paris, Paris, France.

Objectives: Venetoclax combined with hypomethylating agents is a new therapeutic strategy frequently used for treating AML patients who are not eligible for conventional chemotherapy. However, high response rates are heterogeneous due to different mechanisms mediating resistance to venetoclax such as up-regulation of MCL-1 expression. We thus tested the anti-leukemic activity of S63845, a specific MCL-1 inhibitor.

Methods: Apoptosis induces by S63845 with or without venetoclax was evaluated in primary AML samples and in AML cell lines co-cultured or not with bone marrow (BM) mesenchymal stromal cells. Sensitivity of leukemic cells to S63845 was correlated to the expression level of BCL-2, MCL-1, and BCL-XL determined by Western Blot and mass spectrometry-based proteomics.

Results: We observed that even if MCL-1 expression is weak compared to BCL-2, S63845 induces apoptosis of AML cells and strongly synergizes with venetoclax. Furthermore, AML cells resistant to venetoclax are highly sensitive to S63845. Interestingly, the synergistic effect of S63845 toward venetoclax-mediated apoptosis of AML cells is still observed in a context of interaction with the BM microenvironment that intrinsically mediates resistance to BCL2 inhibition.

Conclusion: These results are therefore of great relevance for clinicians as they provide the rational for combining BCL-2 and MCL-1 inhibition in AML.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ejh.13492DOI Listing
November 2020

Disease characteristics of MCT8 deficiency: an international, retrospective, multicentre cohort study.

Lancet Diabetes Endocrinol 2020 07;8(7):594-605

Department of Diabetes and Endocrinology, Women's and Children's Hospital, North Adelaide, SA, Australia.

Background: Disordered thyroid hormone transport, due to mutations in the SLC16A2 gene encoding monocarboxylate transporter 8 (MCT8), is characterised by intellectual and motor disability resulting from cerebral hypothyroidism and chronic peripheral thyrotoxicosis. We sought to systematically assess the phenotypic characteristics and natural history of patients with MCT8 deficiency.

Methods: We did an international, multicentre, cohort study, analysing retrospective data from Jan 1, 2003, to Dec 31, 2019, from patients with MCT8 deficiency followed up in 47 hospitals in 22 countries globally. The key inclusion criterion was genetically confirmed MCT8 deficiency. There were no exclusion criteria. Our primary objective was to analyse the overall survival of patients with MCT8 deficiency and document causes of death. We also compared survival between patients who did or did not attain full head control by age 1·5 years and between patients who were or were not underweight by age 1-3 years (defined as a bodyweight-for-age Z score <-2 SDs or <5th percentile according to WHO definition). Other objectives were to assess neurocognitive function and outcomes, and clinical parameters including anthropometric characteristics, biochemical markers, and neuroimaging findings.

Findings: Between Oct 14, 2014, and Jan 17, 2020, we enrolled 151 patients with 73 different MCT8 (SLC16A2) mutations. Median age at diagnosis was 24·0 months (IQR 12·0-60·0, range 0·0-744·0). 32 (21%) of 151 patients died; the main causes of mortality in these patients were pulmonary infection (six [19%]) and sudden death (six [19%]). Median overall survival was 35·0 years (95% CI 8·3-61·7). Individuals who did not attain head control by age 1·5 years had an increased risk of death compared with patients who did attain head control (hazard ratio [HR] 3·46, 95% CI 1·76-8·34; log-rank test p=0·0041). Patients who were underweight during age 1-3 years had an increased risk for death compared with patients who were of normal bodyweight at this age (HR 4·71, 95% CI 1·26-17·58, p=0·021). The few motor and cognitive abilities of patients did not improve with age, as evidenced by the absence of significant correlations between biological age and scores on the Gross Motor Function Measure-88 and Bayley Scales of Infant Development III. Tri-iodothyronine concentrations were above the age-specific upper limit in 96 (95%) of 101 patients and free thyroxine concentrations were below the age-specific lower limit in 94 (89%) of 106 patients. 59 (71%) of 83 patients were underweight. 25 (53%) of 47 patients had elevated systolic blood pressure above the 90th percentile, 34 (76%) of 45 patients had premature atrial contractions, and 20 (31%) of 64 had resting tachycardia. The most consistent MRI finding was a global delay in myelination, which occurred in 13 (100%) of 13 patients.

Interpretation: Our description of characteristics of MCT8 deficiency in a large patient cohort reveals poor survival with a high prevalence of treatable underlying risk factors, and provides knowledge that might inform clinical management and future evaluation of therapies.

Funding: Netherlands Organisation for Health Research and Development, and the Sherman Foundation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/S2213-8587(20)30153-4DOI Listing
July 2020

Positron emission tomography evaluation of oxime countermeasures in live rats using the tracer O-(2-[ F]fluoroethyl)-O-(p-nitrophenyl)methylphosphonate [ F]-VXS.

Ann N Y Acad Sci 2020 11 20;1479(1):180-195. Epub 2020 May 20.

Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana.

Oxime antidotes regenerate organophosphate-inhibited acetylcholinesterase (AChE). Although they share a common mechanism of AChE reactivation, the rate and amount of oxime that enters the brain are critical to the efficacy, a process linked to the oxime structure and charge. Using a platform based on the organophosphate [ F]-VXS as a positron emission tomography tracer for active AChE, the in vivo distribution of [ F]-VXS was evaluated after an LD dose (250 μg/kg) of the organophosphate paraoxon (POX) and following oximes as antidotes. Rats given [ F]-VXS tracer alone had significantly higher radioactivity (two- to threefold) in the heart and lung than rats given LD POX at 20 or 60 min prior to [ F]-VXS. When rats were given LD POX followed by 2-PAM (cationic), RS194b (ionizable), or monoisonitrosoacetone (MINA) (neutral), central nervous system (CNS) radioactivity returned to levels at or above untreated naive rats (no POX), whereas CNS radioactivity did not increase in rats given the dication oximes HI-6 or MMB-4. MINA showed a significant, pairwise increase in CNS brain radioactivity compared with POX-treated rats. This new in vivo dynamic platform using [ F]-VXS tracer measures and quantifies peripheral and CNS relative changes in AChE availability after POX exposure and is suitable for comparing oxime delivery and AChE reactivation in rats.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/nyas.14363DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7677195PMC
November 2020

Genetic variation in Austrostrongylus thylogale Johnston & Mawson, 1940 (Nematoda: Trichostrongylida) from the tammar wallaby, Notamacropus eugenii (Gray), and the quokka, Setonix brachyurus (Quoy & Gaimard) (Marsupialia: Macropodidae) in Australia.

Parasit Vectors 2020 Mar 14;13(1):135. Epub 2020 Mar 14.

Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Werribee, VIC, 3030, Australia.

Background: Australian marsupials harbour a diverse array of helminth parasites. Despite current attempts to assess the extent of this diversity in macropodid hosts, it has been suggested that unique parasite fauna of Australian wildlife is difficult to document comprehensively due to the common occurrence of cryptic species. This paper assessed genetic variation within Austrostrongylus thylogale Johnston & Mawson, 1940 from the tammar wallaby, Notamacropus eugenii (Gray), and the quokka, Setonix brachyurus (Quoy & Gaimard), from different localities using the molecular characterisation of the internal transcribed spacers (ITS) within the nuclear ribosomal DNA.

Methods: Thirty-seven specimens of A. thylogale collected from N. eugenii (from Parndana, Kangaroo Island, South Australia, and Perup, Western Australia) and S. brachyurus (from Wellington Dam, Western Australia) were characterised using a molecular-phylogenetic approach utilising the first (ITS1) and second (ITS2) internal transcribed spacers.

Results: Genetic variation was detected in both ITS1 and ITS2 between specimens of A. thylogale from N. eugenii and S. brachyurus; however, no variation was detected between specimens collected from N. eugenii from Parndana, South Australia, and Perup, Western Australia. Furthermore, the phylogenetic analyses of ITS sequences showed two clades of A. thylogale originating from two hosts, N. eugenii and S. brachyurus, suggesting the presence of cryptic species.

Conclusions: This study provides evidence of genetic variation within A. thylogale based on collections from two different host species. Morphological studies are required to fully confirm the presence of a new species or cryptic species. Further molecular studies using a larger number of specimens are warranted to explore the genetic variation between A. thylogale from different geographical localities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13071-020-4007-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071675PMC
March 2020

Sensing Living Bacteria Using d-Alanine-Derived C Radiotracers.

ACS Cent Sci 2020 Feb 4;6(2):155-165. Epub 2020 Feb 4.

Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California 94158, United States.

Incorporation of d-amino acids into peptidoglycan is a unique metabolic feature of bacteria. Since d-amino acids are not metabolic substrates in most mammalian tissues, this difference can be exploited to detect living bacteria . Given the prevalence of d-alanine in peptidoglycan muropeptides, as well as its role in several antibiotic mechanisms, we targeted this amino acid for positron emission tomography (PET) radiotracer development. d-[3-C]Alanine and the dipeptide d-[3-C]alanyl-d-alanine were synthesized via asymmetric alkylation of glycine-derived Schiff-base precursors with [C]methyl iodide in the presence of a cinchonidinium phase-transfer catalyst. In cell experiments, both tracers showed accumulation by a wide variety of both Gram-positive and Gram-negative pathogens including and . In a mouse model of acute bacterial myositis, d-[3-C]alanine was accumulated by living microorganisms but was not taken up in areas of sterile inflammation. When compared to existing clinical nuclear imaging tools, specifically 2-deoxy-2-[F]fluoro-d-glucose and a gallium citrate radiotracer, d-alanine showed more bacteria-specific uptake. Decreased d-[3-C]alanine uptake was also observed in antibiotic-sensitive microbes after antimicrobial therapy, when compared to that in resistant organisms. Finally, prominent uptake of d-[3-C]alanine uptake was seen in rodent models of discitis-osteomyelitis and pneumonia. These data provide strong justification for clinical translation of d-[3-C]alanine to address a number of important human infections.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acscentsci.9b00743DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7047270PMC
February 2020

CCI52 sensitizes tumors to 6-mercaptopurine and inhibits MYCN-amplified tumor growth.

Biochem Pharmacol 2020 02 17;172:113770. Epub 2019 Dec 17.

Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Sydney, Kensington, NSW, Australia; School of Women's and Children's Health, UNSW Sydney, Kensington, NSW, Australia. Electronic address:

The antimetabolite 6-mercaptopurine (6-MP) is an important component in the treatment of specific cancer subtypes, however, the development of drug resistance and dose-limiting toxicities can limit its effectiveness. The therapeutic activity of 6-MP requires cellular uptake, enzymatic conversion to thio-GMP and incorporation of thio-GTP into RNA and DNA, as well as inhibition of de novo purine synthesis by methyl-thio-IMP. Mechanisms that prevent 6-MP entry into the cell, prevent 6-MP metabolism or deplete thiopurine intermediates, can all lead to 6-MP resistance. We previously conducted a high-throughput screen for inhibitors of the multidrug transporter MRP4 using 6-MP sensitivity as the readout. In addition to MRP4-specific inhibitors, we identified a compound, CCI52, that sensitized cell lines to 6-MP independent of this transporter. CCI52 and its more stable analogue CCI52-14 also function as effective chemosensitizers in vivo, substantially extending survival in a transgenic mouse cancer model treated with 6-MP. Chemosensitization was associated with an increase in thio-IMP, suggesting that CCI52 functions directly on 6-MP uptake or metabolism. In addition to its chemosensitizing effects, CCI52 and CCI52-14 inhibited the growth of MYCN-amplified high-risk neuroblastoma cell lines and delayed tumor progression in a MYCN-driven, transgenic mouse model of neuroblastoma. These multifunctional inhibitors may be useful for the further development of anticancer agents and as tools to better understand 6-MP metabolism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bcp.2019.113770DOI Listing
February 2020

High Enantiomeric Excess In-Loop Synthesis of d-[methyl-C]Methionine for Use as a Diagnostic Positron Emission Tomography Radiotracer in Bacterial Infection.

ACS Infect Dis 2020 01 21;6(1):43-49. Epub 2019 Nov 21.

Department of Radiology and Biomedical Imaging , University of California, San Francisco , San Francisco , California 94107 , United States.

Currently, there exists no accurate, noninvasive clinical imaging method to detect living bacteria . Our goal is to provide a positron emission tomography (PET) method to image infection by targeting bacteria-specific metabolism. Standard of care methodologies detect morphologic changes, image immunologic response to infection, or employ invasive tissue sampling with associated patient morbidity. These strategies, however, are not specific for living bacteria and are often inadequate to detect bacterial infection during fever workup. As such, there is an unmet clinical need to identify and validate new imaging tools suitable for noninvasive, (PET) imaging of living bacteria. We have shown that d-[methyl-C]methionine (d-[C]Met) can distinguish active bacterial infection from sterile inflammation in a murine infection model and is sensitive to both Gram-positive and Gram-negative bacteria. Here, we report an automated and >99% enantiomeric excess (ee) synthesis of d-[C]Met from a linear d-homocysteine precursor, a significant improvement over the previously reported synthesis utilizing a d-homocysteine thiolactone hydrochloride precursor with approximately 75-85% ee. Furthermore, we took additional steps toward applying d-[C]Met to infected patients. d-[C]Met was subject to a panel of clinically relevant bacterial strains and demonstrated promising sensitivity to these pathogens. Finally, we performed radiation dosimetry in a normal murine cohort to set the stage for translation to humans in the near future.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsinfecdis.9b00196DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7364312PMC
January 2020

Synthesis and Initial Biological Evaluation of Boron-Containing Prostate-Specific Membrane Antigen Ligands for Treatment of Prostate Cancer Using Boron Neutron Capture Therapy.

Mol Pharm 2019 09 16;16(9):3831-3841. Epub 2019 Aug 16.

Department of Radiology and Biomedical Imaging , University of California , San Francisco , California , United States.

Boron neutron capture therapy (BNCT) is a therapeutic modality which has been used for the treatment of cancers, including brain and head and neck tumors. For effective treatment via BNCT, efficient and selective delivery of a high boron dose to cancer cells is needed. Prostate-specific membrane antigen (PSMA) is a target for prostate cancer imaging and drug delivery. In this study, we conjugated boronic acid or carborane functional groups to a well-established PSMA inhibitor scaffold to deliver boron to prostate cancer cells and prostate tumor xenograft models. Eight boron-containing PSMA inhibitors were synthesized. All of these compounds showed a strong binding affinity to PSMA in a competition radioligand binding assay (IC from 555.7 to 20.3 nM). Three selected compounds , , and were administered to mice, and their blocking of Ga-PSMA-11 uptake was demonstrated through a positron emission tomography (PET) imaging and biodistribution experiment. Biodistribution analysis demonstrated boron uptake of 4-7 μg/g in 22Rv1 prostate xenograft tumors and similar tumor/muscle ratios compared to the ratio for the most commonly used BNCT compound, 4-borono-l-phenylalanine (BPA). Taken together, these data suggest a potential role for PSMA targeted BNCT agents in prostate cancer therapy following suitable optimization.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.molpharmaceut.9b00464DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6722010PMC
September 2019

Evidence for IL-35 Expression in Diffuse Large B-Cell Lymphoma and Impact on the Patient's Prognosis.

Front Oncol 2019 28;9:563. Epub 2019 Jun 28.

Sorbonne Université, INSERM, CNRS, Centre D'Immunologie et des Maladies Infectieuses (Cimi-Paris), Paris, France.

IL-35 is an immunosuppressive cytokine of the IL-12 family consisting of two subunits, EBV-induced gene 3 (EBI3) and p35. It has been shown to play a pro-tumor role in murine tumor models, and in various types of human cancer such as colorectal, pancreatic, or liver carcinoma, its expression has been associated with a worse clinical outcome. Here, we show by analyzing gene expression data from public databases and by immunohistochemical studies that IL-35 is overexpressed by tumor cells in diffuse-large B-cell lymphoma (DLBCL) compared to another type of mature aggressive B-cell lymphoma, Burkitt lymphoma. However, while high IL-35 expression was significantly associated with a worse overall survival in DLBCL patients treated with chemotherapy only (cyclophosphamide, doxorubicin, vincristine, prednisone, CHOP), no significant correlation between IL-35 expression levels and the patient outcome was observed in DLBCL patients treated with CHOP combined to rituximab (R-CHOP), the current conventional treatment. In addition, we found that an anti-IL-35 antibody, clone 15k8D10, used to assess IL-35 expression by immunohistochemistry in various human tissues including tumors does not recognize IL-35 heterodimer, nor its individual subunits EBI3 and p35, but cross-reacts with human IgG1, indicating that IL-35 expression in human cancers needs to be re-evaluated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fonc.2019.00563DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6611226PMC
June 2019

Slowed gastric emptying and improved oral glucose tolerance produced by a nanomolar-potency inhibitor of calcium-activated chloride channel TMEM16A.

FASEB J 2019 10 12;33(10):11247-11257. Epub 2019 Jul 12.

Department of Medicine and Physiology, University of California, San Francisco, San Francisco, California, USA.

Interstitial cells of Cajal, which express the calcium-activated chloride channel transmembrane member 16A (TMEM16A), are an important determinant of gastrointestinal (GI) motility. We previously identified the acylaminocycloalkylthiophene class of TMEM16A inhibitors, which, following medicinal chemistry, gave analog 2-bromodifluoroacetylamino-5,6,7,8-tetrahydro-4-cyclohepta[]thiophene-3-carboxylic acid -tolylamide (TM-23) with 30 nM half-maximal inhibitory concentration. Here, we tested the efficacy of TM-23 for inhibition of GI motility in mice. In isolated murine gastric antrum, TM-23 strongly inhibited spontaneous and carbachol-stimulated rhythmic contractions. Pharmacokinetic analysis showed predicted therapeutic concentrations of TM-23 for at least 4 h following a single oral or intraperitoneal dose at 10 mg/kg. Gastric emptying, as assessed following an oral bolus of phenol red or independently by [Tc]-diethylenetriamine pentaacetic acid scintigraphy, was reduced by TM-23 by ∼60% at 20 min. Interestingly, there was little effect of TM-23 on baseline whole-gut transit time or time to diarrhea induced by castor oil. Consequent to the delay in gastric emptying, TM-23 administration significantly reduced the elevation in blood sugar in mice following an oral but not intraperitoneal glucose load. These results provide pharmacological evidence for involvement of TMEM16A in gastric emptying and suggest the utility of TMEM16A inhibition in disorders of accelerated gastric emptying, such as dumping syndrome, and potentially for improving glucose tolerance in diabetes mellitus/metabolic syndrome and enhancing satiety in obesity.-Cil, O., Anderson, M. O., Yen, R., Kelleher, B., Huynh, T. L., Seo, Y., Nilsen, S. P., Turner, J. R., Verkman, A. S. Slowed gastric emptying and improved oral glucose tolerance produced by a nanomolar-potency inhibitor of calcium-activated chloride channel TMEM16A.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1096/fj.201900858RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6766656PMC
October 2019

CT can stratify patients as low risk for tibial neuropathy following a talus fracture.

Emerg Radiol 2019 Oct 8;26(5):541-548. Epub 2019 Jul 8.

Department of Orthopaedic Surgery, Emory University Hospital, Atlanta, GA, USA.

Objective: Determine the incidence of tibial neuropathy following talus fractures and CT's ability to stratify patients at risk for developing post-traumatic neuropathy.

Materials And Methods: In this IRB-approved retrospective analysis, 71 talus fractures and 8 contralateral control ankle CTs were reviewed by one observer blinded to clinical information. CT evidence suggestive of tibial neurovascular bundle injury included nerve displacement, perineural fat effacement/edema, and bone touching nerve. The association between these CT findings and clinically evident tibial neuropathy was analyzed. A semi-quantitative likelihood score was assigned based on the degree of the CT findings around the nerve. Interobserver agreement was calculated between 2 other readers.

Results: Twenty-five percent of patients in this cohort had clinical evidence of tibial neuropathy. There was a high specificity (0.87-0.93) and negative predictive value (0.83-0.87), a moderate accuracy (0.80-0.82), but a lower sensitivity (0.33-0.56) associated with the CT findings. Among the CT findings, nerve displacement (p < 0.0001) and bone touching nerve (p = 0.01) were associated with tibial neuropathy. A likelihood score of 2-5 was associated (p = 0.007-0.015) with tibial neuropathy. The presence of tibial neuropathy and nerve recovery were not associated with hospital length of stay, while CT findings were. There was substantial agreement between the three readers: likelihood scores 2+ (k = 0.78) and 3+ (k = 0.72).

Conclusions: Tibial neuropathy occurs following talus fractures, and CT findings may help surgeons narrow down the number of patients requiring close neurological follow-up.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10140-019-01706-yDOI Listing
October 2019

A case report and focused literature review of d-penicillamine and severe neutropenia: A serious toxicity from a seldom-used drug.

Clin Case Rep 2019 May 9;7(5):990-994. Epub 2019 Apr 9.

University of Iowa Healthcare Iowa City Iowa.

Prescribing d-penicillamine for Wilson's disease must be accompanied by vigilant monitoring, including a complete blood cell count with differential. For most, this should occur once or twice weekly during the first month of therapy and during periods of dose escalation, then every two weeks for six additional months, then monthly.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ccr3.2125DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6509885PMC
May 2019

PET/CT Imaging of Human TNFα Using [Zr]Certolizumab Pegol in a Transgenic Preclinical Model of Rheumatoid Arthritis.

Mol Imaging Biol 2020 02;22(1):105-114

Department of Radiology and Molecular Imaging, University of California San Francisco, 185 Berry St., Suite 350, San Francisco, CA, 94107, USA.

Purpose: Tumor necrosis factor alpha (TNFα) drives inflammation and bone degradation in patients with rheumatoid arthritis (RA). Some RA patients experience a rapid clinical response to TNFα inhibitors such as certolizumab pegol (CZP) while other patients show limited to no response. Current methods for imaging RA have limited sensitivity and do not assist in the selection of patients most likely to respond to immune-mediated therapy. Herein, we developed a novel positron emission tomography (PET) radiotracer for immuno-PET imaging of TNFα in transgenic human TNFα-expressing mice.

Procedures: CZP was modified with p-isothiocyanatobenzyl-deferoxamine (DFO) and radiolabeled with Zr-89. The biological activity of [Zr]DFO-CZP was evaluated by HPLC and binding assay using human recombinant TNFα (hTNFα). The feasibility of specific immuno-PET imaging of human TNFα was assessed in a transgenic mouse model of RA that expresses human TNFα. This model resembles the progression of RA in humans by maintaining lower levels of circulating hTNFα and exhibits chronic arthritis in the forepaw and hind paw joints. The dosimetry of [Zr]DFO-CZP in humans was estimated using microPET/CT imaging in Sprague Dawley rats.

Results: [Zr]DFO-CZP was isolated with radiolabeling yields of 85 ± 6 % (n = 5) and specific activities ranging from 74 to 185 MBq/mg (n = 5). Following size exclusion purification, the radiochemical purity of [Zr]DFO-CZP was greater than 97 %. [Zr]DFO-CZP retained high immunoreactivity with more than 95 % of the radioactivity shifted into higher molecular weight complexes. Images showed increasing uptake of the tracer in forepaw and hind paw joints with disease progression. No uptake was observed in the model previously administered with an excess amount of unmodified CZP and in normal control mice, demonstrating in vivo specific uptake of [Zr]DFO-CZP.

Conclusion: The feasibility of immuno-PET imaging of human TNFα with [Zr]DFO-CZP has been demonstrated in a preclinical model of RA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11307-019-01363-0DOI Listing
February 2020

Imaging of Activated T Cells as an Early Predictor of Immune Response to Anti-PD-1 Therapy.

Cancer Res 2019 07 7;79(13):3455-3465. Epub 2019 May 7.

Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, California.

Compelling evidence points to immune cell infiltration as a critical component of successful immunotherapy. However, there are currently no clinically available, noninvasive methods capable of evaluating immune contexture prior to or during immunotherapy. In this study, we evaluate a T-cell-specific PET agent, [18F]F-AraG, as an imaging biomarker predictive of response to checkpoint inhibitor therapy. We determined the specificity of the tracer for activated T cells and in a virally induced model of rhabdomyosarcoma. Of all immune cells tested, activated human CD8 effector cells showed the highest accumulation of [18F]F-AraG. Isolation of lymphocytes from the rhabdomyosarcoma tumors showed that more than 80% of the intratumoral signal came from accumulation of [18F]F-AraG in immune cells, primarily CD8 and CD4. Longitudinal monitoring of MC38 tumor-bearing mice undergoing anti-PD-1 treatment revealed differences in signal between PD-1 and isotype antibody-treated mice early into treatment. The differences in [18F]F-AraG signal were also apparent between responders and nonresponders to anti-PD-1 therapy. Importantly, we found that the signal in the tumor-draining lymph nodes provides key information about response to anti-PD-1 therapy. Overall, [18F]F-AraG has potential to serve as a much needed immunomonitoring clinical tool for timely evaluation of immunotherapy. SIGNIFICANCE: These findings reveal differences in T-cell activation between responders and nonresponders early into anti-PD-1 treatment, which may impact many facets of immuno-oncology, including patient selection, management, and development of novel combinatorial approaches.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/0008-5472.CAN-19-0267DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6606349PMC
July 2019

An Unusual Cause of Metabolic Alkalosis and Hypocalcemia in Childhood.

Clin Chem 2019 04;65(4):514-517

Department of Chemical Pathology, Pathology Queensland, Herston, Queensland, Australia.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1373/clinchem.2018.287136DOI Listing
April 2019

Disparities in follow-up care for ballistic and non-ballistic long bone lower extremity fractures.

Injury 2018 Dec 4;49(12):2193-2197. Epub 2018 Oct 4.

Emory University School of Medicine, Department of Orthopaedics, United States. Electronic address:

Objectives: To describe differences in follow-up compliance and emergency department (ED) visits between ballistic and non-ballistic operative lower extremity fracture patients.

Design: Retrospective study.

Setting: Urban level 1 trauma center.

Patients/participants: Patients age ≥18 years with ≥1 tibia or femur fractures treated with ORIF or intramedullary nailing (IMN) between September 1, 2013 and August 31, 2015.

Main Outcome Measure: A compliance fraction calculated as ([number of attended follow-up visits] / [number of attended follow-up visits + number of missed follow-up visits]) and ED visits in the post-operative period.

Results: 612 patients were studied. Patients with ballistic lower extremity fractures had a younger mean age (30.8 years v. 41.6 years; p < 0.0001); a shorter length of stay (5.00 days v. 8.00 days; p < 0.0001); and were more likely to be male (92.6% v. 68%; p < 0.0001) and African-American (90.1% v. 63.1%; p < 0.0001) when compared to non-ballistic long bone injuries. Increased follow-up compliance (defined as a compliance fraction ≥0.75) was associated with having a non-ballistic fracture (OR 1.73, 1.13-2.64; p = 0.01), not having an ED visit (OR 2.08, 1.30-3.33; p = 0.002), and being female (OR 1.82, 1.27-2.61; p = 0.001). Increased ED utilization (≥ 1 ED visit) was associated with ballistic mechanism (OR 1.95, 1.20-3.16; p = 0.006), a low follow-up compliance fraction (OR 2.08, 1.30-3.33; p = 0.0019), homelessness (OR 3.91, 1.53-9.98; p = 0.006), and African-American race (OR 2.26, 1.26-4.05; p = 0.05). Scheduling a specific follow-up visit on the discharge summary did not predict higher compliance (OR 1.51, 0.98-2.33; p = 0.06). Conversely, the lack of a specific follow-up visit scheduled on the discharge summary did not predict ED utilization (OR 0.63, 0.34-1.17; p = 0.14).

Conclusion: The results of this study demonstrate that increased utilization of the ED was associated with ballistic fractures, homelessness, decreased clinic compliance, and African American race. Furthermore, patients with non-ballistic injuries, women, and those without any ED visit were more likely to have higher outpatient clinic compliance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.injury.2018.09.053DOI Listing
December 2018

Radiosynthesis, ex Vivo Biodistribution, and in Vivo Positron Emission Tomography Imaging Evaluations of [C]2-Pyridinealdoxime Methiodide ([C]2-PAM): A First-In-Class Antidote Tracer for Organophosphate Intoxication.

ACS Chem Neurosci 2018 12 20;9(12):3007-3014. Epub 2018 Aug 20.

Department of Biomedical and Pharmaceutical Sciences , University of Montana , Missoula , Montana 59812 , United States.

2-Pyridinealdoxime methiodide (2-PAM) is a widely used antidote for the treatment of organophosphorus (OP) exposure that reactivates the target protein acetylcholinesterase. Carbon-11 2-PAM was prepared to more fully understand the in vivo mode of action, distribution, and dynamic qualities of this important countermeasure. Alkylation of 2-pyridinealdoxime with [C]CHI provided the first-in-class [C]2-PAM tracer in 3.5% decay corrected radiochemical yield from [C]CHI, >99% radiochemical purity, and 4831 Ci/mmol molar activity. [C]2-PAM tracer distribution was evaluated by ex vivo biodistribution and in vivo dynamic positron emission tomography (PET) imaging in naïve (OP exposure deficient) rats. Tracer alone and tracer coinjected with a body mass-scaled human therapeutic dose of 30 mg/kg nonradioactive 2-PAM demonstrated statistically similar tissue and blood distribution profiles with the greatest uptake in kidney and significantly lower levels in liver, heart, and lung with lesser amounts in blood and brain. The imaging and biodistribution data show that radioactivity uptake in brain and peripheral organs is rapid and characterized by differential tissue radioactivity washout profiles. Analysis of arterial blood samples taken 5 min after injection showed ∼82% parent [C]2-PAM tracer. The imaging and biodistribution data are now established, enabling future comparisons to outcomes acquired in OP intoxicated rodent models.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acschemneuro.8b00212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699170PMC
December 2018
-->