Helen Day

Severity of the aggression/anxiety-depression/attention child behavior checklist profile discriminates between different levels of deficits in emotional regulation in youth with attention-deficit hyperactivity disorder.

Objective: We examined whether severity scores (1 SD vs 2 SDs) of a unique profile of the Child Behavior Checklist (CBCL) consisting of the Anxiety/Depression, Aggression, and Attention (AAA) scales would help differentiate levels of deficits in children with attention-deficit hyperactivity disorder (ADHD). Study Design: Subjects were 197 children with ADHD and 224 without ADHD. We defined deficient emotional self-regulation (DESR) as an aggregate cutoff score of >180 but <210 (1 SD) on the AAA scales of the CBCL (CBCL-DESR) and Severe Dysregulation as an aggregate cutoff score of ≥210 on the same scales (CBCL-Severe Dysregulation). All subjects were assessed with structured diagnostic interviews and a range of functional measures. Results: Thirty-six percent of children with ADHD had a positive CBCL-DESR profile versus 2% of controls (p < .001) and 19% had a positive CBCL-Severe Dysregulation profile versus 0% of controls (p < .001). The subjects positive for the CBCL-Severe Dysregulation profile differed selectively from those with the CBCL-DESR profile in having higher rates of unipolar and bipolar mood disorders, oppositional defiant and conduct disorders, psychiatric hospitalization at both baseline and follow-up assessments, and a higher rate of the CBCL-Severe Dysregulation in siblings. In contrast, the CBCL-DESR was associated with higher rates of comorbid disruptive behavior, anxiety disorders, and impaired interpersonal functioning compared with other ADHD children. Conclusion: Severity scores of the AAA CBCL profiles can help distinguish 2 groups of emotional regulation problems in children with ADHD.

Deficient emotional self-regulation and pediatric attention deficit hyperactivity disorder: a family risk analysis

BACKGROUND Although deficient emotional self-regulation (DESR) is associated with attention deficit hyperactivity disorder (ADHD), little research investigates this association and little is known about its etiology. Family studies provide a method of clarifying the co-occurrence of clinical features, but no family studies have yet addressed ADHD and DESR in children. METHOD Subjects were 242 children with ADHD and 224 children without ADHD. DESR was operationalized using an aggregate score ≥180 and <210 in the anxious/depressed, attention and aggression scales (AAA profile) of the Child Behavior Checklist (CBCL), termed the CBCL-DESR profile. The CBCL-bipolar (CBCL-BP) profile was defined as ≥210 on the CBCL-AAA scale. We examined the familial transmission of ADHD and the CBCL-AAA scale in families selected through probands with and without these conditions. RESULTS We found a linear increase in the prevalence of CBCL-DESR in siblings as indexed by the Control, ADHD, ADHD+CBCL-DESR and ADHD+CBCL-BP proband groups. While the ADHD siblings were at elevated risk for both the CBCL-DESR and CBCL-BP compared with non-ADHD siblings, a significantly higher rate of CBCL-BP in the siblings of ADHD+CBCL-BP probands was found compared with siblings of the Control probands. CONCLUSIONS ADHD shows the same degree of familial transmission in the presence or absence of DESR. CBCL-DESR and CBCL-BP are familial, but further work is needed to determine if these definitions are distinctly familial or represent a continuum of the same psychopathology.

Pycup—A Bifunctional, Cage-like Ligand for 64Cu Radiolabeling

In developing targeted probes for positron emission tomography (PET) based on (64)Cu, stable complexation of the radiometal is key, and a flexible handle for bioconjugation is highly advantageous. Here, we present the synthesis and characterization of the chelator pycup and four derivatives. Pycup is a cross-bridged cyclam derivative with a pyridyl donor atom integrated into the cross-bridge resulting in a pentadentate ligand. The pycup platform provides kinetic inertness toward (64)Cu dechelation and offers versatile bioconjugation chemistry. We varied the number and type of additional donor atoms by alkylation of the remaining two secondary amines, providing three model ligands, pycup2A, pycup1A1Bn, and pycup2Bn, in 3-4 synthetic steps from cyclam. All model copper complexes displayed very slow decomplexation in 5 M HCl and 90 °C (t1/2: 1.5 h for pycup1A1Bn, 2.7 h for pycup2A, 20.3 h for pycup2Bn). The single crystal crystal X-ray structure of the [Cu(pycup2Bn)](2+) complex showed that the copper was coordinated in a trigonal, bipyramidal manner. The corresponding radiochemical complexes were at least 94% stable in rat plasma after 24 h. Biodistribution studies conducted in Balb/c mice at 2 h postinjection of (64)Cu labeled pycup2A revealed low residual activity in kidney, liver, and blood pool with predominantly renal clearance observed. Pycup2A was readily conjugated to a fibrin-targeted peptide and labeled with (64)Cu for successful PET imaging of arterial thrombosis in a rat model, demonstrating the utility of our new chelator in vivo.

Is ADHD a Risk Factor for High School Dropout? A Controlled Study

Objective: This study examined whether ADHD was an independent contributor to grade retention when adjusting for IQ, learning disorders, and social class. Method: Outcome data was from participants in studies at Massachusetts General Hospital (n = 404 ADHD, n = 349 controls) who underwent psychiatric interviews, socioeconomic status measures, and IQ testing. Results: 28% of individuals with ADHD repeated a grade compared with 7% of controls (p < .001). Among participants with ADHD, social class, and IQ were significant predictors of high school dropout or repeated grade. An interaction effect of ADHD and gender was also found with females with ADHD having a higher risk ratio for repeated grade/dropout compared with males with ADHD. Conclusion: Participants with ADHD were significantly more likely to repeat a grade, adjusting for all other variables indicating the critical importance of early identification of ADHD to help mitigate adverse educational outcomes. (J. of Att. Dis. 2016; 20(5) 383-389)

In vivo molecular imaging of thrombosis and thrombolysis using a fibrin-binding positron emission tomographic probe.

Background—Fibrin is a major component of arterial and venous thrombi and represents an ideal candidate for molecular imaging of thrombosis. Here, we describe imaging properties and target uptake of a new fibrin-specific positron emission tomographic probe for thrombus detection and therapy monitoring in 2 rat thrombosis models. Methods and Results—The fibrin-binding probe FBP7 was synthesized by conjugation of a known short cyclic peptide to a cross-bridged chelator (CB-TE2A), followed by labeling with copper-64. Adult male Wistar rats (n=26) underwent either carotid crush injury (mural thrombosis model) or embolic stroke (occlusive thrombosis model) followed by recombinant tissue-type plasminogen activator treatment (10 mg/kg, IV). FBP7 detected thrombus location in both animal models with a high positron emission tomographic target-to-background ratio that increased over time (>5-fold at 30–90 minutes, >15-fold at 240–285 minutes). In the carotid crush injury animals, biodistribution analysis confirmed high probe uptake in the thrombotic artery (≈0.5%ID/g; >5-fold greater than blood and other tissues of the head and thorax). Similar results were obtained from ex vivo autoradiography of the ipsilateral versus contralateral carotid arteries. In embolic stroke animals, positron emission tomographic–computed tomographic imaging localized the clot in the internal carotid/middle cerebral artery segment of all rats. Time-dependent reduction of activity at the level of the thrombus was detected in recombinant tissue-type plasminogen activator–treated rats but not in vehicle-injected animals. Brain autoradiography confirmed clot dissolution in recombinant tissue-type plasminogen activator–treated animals, but enduring high thrombus activity in control rats. Conclusions—We demonstrated that FBP7 is suitable for molecular imaging of thrombosis and thrombolysis in vivo and represents a promising candidate for bench-to-bedside translation.

3D molecular MR imaging of liver fibrosis and response to rapamycin therapy in a bile duct ligation rat model

BACKGROUND & AIMS Liver biopsy, the gold standard for assessing liver fibrosis, suffers from limitations due to sampling error and invasiveness. There is therefore a critical need for methods to non-invasively quantify fibrosis throughout the entire liver. The goal of this study was to use molecular Magnetic Resonance Imaging (MRI) of Type I collagen to non-invasively image liver fibrosis and assess response to rapamycin therapy. METHODS Liver fibrosis was induced in rats by bile duct ligation (BDL). MRI was performed 4, 10, or 18 days following BDL. Some BDL rats were treated daily with rapamycin starting on day 4 and imaged on day 18. A three-dimensional (3D) inversion recovery MRI sequence was used to quantify the change in liver longitudinal relaxation rate (ΔR1) induced by the collagen-targeted probe EP-3533. Liver tissue was subjected to pathologic scoring of fibrosis and analyzed for Sirius Red staining and hydroxyproline content. RESULTS ΔR1 increased significantly with time following BDL compared to controls in agreement with ex vivo measures of increasing fibrosis. Receiver operating characteristic curve analysis demonstrated the ability of ΔR1 to detect liver fibrosis and distinguish intermediate and late stages of fibrosis. EP-3533 MRI correctly characterized the response to rapamycin in 11 out of 12 treated rats compared to the standard of collagen proportional area (CPA). 3D MRI enabled characterization of disease heterogeneity throughout the whole liver. CONCLUSIONS EP-3533 allowed for staging of liver fibrosis, assessment of response to rapamycin therapy, and demonstrated the ability to detect heterogeneity in liver fibrosis.

Effect of Chelate Type and Radioisotope on the Imaging Efficacy of 4 Fibrin-Specific PET Probes

Thrombus formation plays a major role in cardiovascular diseases, but noninvasive thrombus imaging is still challenging. Fibrin is a major component of both arterial and venous thrombi and represents an ideal candidate for imaging of thrombosis. Recently, we showed that 64Cu-DOTA–labeled PET probes based on fibrin-specific peptides are suitable for thrombus imaging in vivo; however, the metabolic stability of these probes was limited. Here, we describe 4 new probes using either 64Cu or aluminum fluoride (Al18F) chelated to 2 NOTA derivatives. Methods: Probes were synthesized using a known fibrin-specific peptide conjugated to either NODAGA (FBP8, FBP10) or NOTA-monoamide (FBP9, FBP11) as chelators, followed by labeling with 64Cu (FBP8 and FBP9) or Al18F (FBP10 and FBP11). PET imaging efficacy, pharmacokinetics, biodistribution, and metabolic stability were assessed in a rat model of arterial thrombosis. Results: All probes had similar nanomolar affinity (435–760 nM) for the soluble fibrin fragment DD(E). PET imaging allowed clear visualization of thrombus by all probes, with a 5-fold or higher thrombus-to-background ratio. Compared with the previous DOTA derivative, the new 64Cu probes FBP8 and FBP9 showed substantially improved metabolic stability (>85% intact in blood at 4 h after injection), resulting in high uptake at the target site (0.5–0.8 percentage injected dose per gram) that persisted over 5 h, producing increasingly greater target-to-background ratios. The thrombus uptake was 5- to 20-fold higher than the uptake in the contralateral artery, blood, muscle, lungs, bone, spleen, large intestine, and heart at 2 h after injection and 10- to 40-fold higher at 5 h. The Al18F derivatives FBP10 and FBP11 were less stable, in particular the NODAGA conjugate (FBP10, <30% intact in blood at 4 h after injection), which showed high bone uptake and low thrombus-to-background ratios that decreased over time. The high thrombus-to-contralateral ratios for all probes were confirmed by ex vivo biodistribution and autoradiography. The uptake in the liver (<0.5 percentage injected dose per gram), kidneys, and blood were similar for all tracers, and they all showed predominant renal clearance. Conclusion: FBP8, FBP9, and FBP11 showed excellent metabolic stability and high thrombus-to-background ratios and represent promising candidates for imaging of thrombosis in vivo.

Combined magnetic resonance elastography and collagen molecular magnetic resonance imaging accurately stage liver fibrosis in a rat model

Hepatic fibrosis is associated with an overproduction of matrix proteins and a pathological increase of liver stiffness. Noninvasive magnetic resonance (MR) quantification of matrix can be assessed with a collagen‐binding molecular MR probe and stiffness by MR elastography, complementary techniques. This study used both imaging techniques to more accurately stage hepatic fibrosis in a rat model. Thirty rats with varying levels of diethylnitrosamine‐induced liver fibrosis were imaged before and 45 minutes after injection of collagen‐specific probe EP‐3533. MR elastography was performed in the same imaging session. Changes in liver relaxation rate post–EP‐3533 and liver stiffness were compared to the collagen proportional area determined by histology and to Ishak scoring using receiver operating characteristic analysis. Collagen imaging was most sensitive to early fibrosis, while elastography was more sensitive to advanced fibrosis. This complementary feature enabled the formulation of a composite model using multivariate analysis of variance. This model incorporated the discriminating advantages of both MR techniques, resulting in more accurate staging throughout fibrotic progression. Conclusion: Collagen molecular MR imaging is complementary to MR elastography, and combining the two techniques in a single exam leads to increased diagnostic accuracy for all stages of fibrosis. (Hepatology 2017;65:1015‐1025)

Radiation Dosimetry of the Fibrin-Binding Probe 64Cu-FBP8 and Its Feasibility for PET Imaging of Deep Vein Thrombosis and Pulmonary Embolism in Rats

The diagnosis of deep venous thromboembolic disease is still challenging despite the progress of current thrombus imaging modalities and new diagnostic algorithms. We recently reported the high target uptake and thrombus imaging efficacy of the novel fibrin-specific PET probe 64Cu-FBP8. Here, we tested the feasibility of 64Cu-FBP8 PET to detect source thrombi and culprit emboli after deep vein thrombosis and pulmonary embolism (DVT-PE). To support clinical translation of 64Cu-FBP8, we performed a human dosimetry estimation using time-dependent biodistribution in rats. Methods: Sprague–Dawley rats (n = 7) underwent ferric chloride application on the femoral vein to trigger thrombosis. Pulmonary embolism was induced 30 min or 2 d after DVT by intrajugular injection of a preformed blood clot labeled with 125I-fibrinogen. PET imaging was performed to detect the clots, and SPECT was used to confirm in vivo the location of the pulmonary emboli. Ex vivo γ counting and histopathology were used to validate the imaging findings. Detailed biodistribution was performed in healthy rats (n = 30) at different time points after 64Cu-FBP8 administration to estimate human radiation dosimetry. Longitudinal whole-body PET/MR imaging (n = 2) was performed after 64Cu-FBP8 administration to further assess radioactivity clearance. Results: 64Cu-FBP8 PET imaging detected the location of lung emboli and venous thrombi after DVT-PE, revealing significant differences in uptake between target and background tissues (P < 0.001). In vivo SPECT imaging and ex vivo γ counting confirmed the location of the lung emboli. PET quantification of the venous thrombi revealed that probe uptake was greater in younger clots than in older ones, a result confirmed by ex vivo analyses (P < 0.001). Histopathology revealed an age-dependent reduction of thrombus fibrin content (P = 0.006), further supporting the imaging findings. Biodistribution and whole-body PET/MR imaging showed a rapid, primarily renal, body clearance of 64Cu-FBP8. The effective dose was 0.021 mSv/MBq for males and 0.027 mSv/MBq for females, supporting the feasibility of using 64Cu-FBP8 in human trials. Conclusion: We showed that 64Cu-FBP8 PET is a feasible approach to image DVT-PE and that radiogenic adverse health effects should not limit the clinical translation of 64Cu-FBP8.

Multimodal molecular imaging reveals high target uptake and specificity of 111In and 68Ga labeled fibrin-binding probes for thrombus detection in rats

We recently showed the high target specificity and favorable imaging properties of 64Cu and Al18F PET probes for noninvasive imaging of thrombosis. Here, our aim was to evaluate new derivatives labeled with either with 68Ga, 111In, or 99mTc as thrombus imaging agents for PET and SPECT. In this study, the feasibility and potential of these probes for thrombus imaging was assessed in detail in 2 animal models of arterial thrombosis. The specificity of the probes was further evaluated using a triple-isotope approach with multimodal SPECT/PET/CT imaging. Methods: Radiotracers were synthesized using a known fibrin-binding peptide conjugated to 1,4,7-triazacyclononane,1-glutaric acid-4,7-acetic acid (NODAGA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid monoamide (DOTA-MA), or a diethylenetriamine ligand (DETA-propanoic acid [PA]), followed by labeling with 68Ga (FBP14, 68Ga-NODAGA), 111In (FBP15, 111In-DOTA-MA), or 99mTc (FBP16, 99mTc(CO)3-DETA-PA), respectively. PET or SPECT imaging, biodistribution, pharmacokinetics, and metabolic stability were evaluated in rat models of mural and occlusive carotid artery thrombosis. In vivo target specificity was evaluated by comparing the distribution of the SPECT and PET probes with preformed 125I-labeled thrombi and with a nonbinding control probe using SPECT/PET/CT imaging. Results: All 3 radiotracers showed affinity similar to soluble fibrin fragment DD(E) (inhibition constant = 0.53–0.83 μM). After the kidneys, the highest uptake of 68Ga-FBP14 and 111In-FBP15 was in the thrombus (1.0 ± 0.2 percentage injected dose per gram), with low off-target accumulation. Both radiotracers underwent fast systemic elimination (half-life, 8–15 min) through the kidneys, which led to highly conspicuous thrombi on PET and SPECT images. 99mTc-FBP16 displayed low target uptake and distribution consistent with aggregation or degradation. Triple-isotope imaging experiments showed that both 68Ga-FBP14 and 111In-FBP15, but not the nonbinding derivative 64Cu-d-Cys-FBP8, detected the location of the 125I-labeled thrombus, confirming high target specificity. Conclusion: 68Ga-FBP14 and 111In-FBP15 have high fibrin affinity and thrombus specificity and represent useful PET and SPECT probes for thrombus detection.