Site-Specifically Labeled Immunoconjugates for Molecular Imaging—Part 1: Cysteine Residues and Glycans

Due to their remarkable selectivity and specificity for cancer biomarkers, immunoconjugates have emerged as extremely promising vectors for the delivery of diagnostic radioisotopes and fluorophores to malignant tissues. Paradoxically, however, these tools for precision medicine are synthesized in a remarkably imprecise way. Indeed, the vast majority of immunoconjugates are created via the random conjugation of bifunctional probes (e.g., DOTA-NCS) to amino acids within the antibody (e.g., lysines). Yet antibodies have multiple copies of these residues throughout their macromolecular structure, making control over the location of the conjugation reaction impossible. This lack of site specificity can lead to the formation of poorly defined, heterogeneous immunoconjugates with suboptimal in vivo behavior. Over the past decade, interest in the synthesis and development of site-specifically labeled immunoconjugates—both antibody-drug conjugates as well as constructs for in vivo imaging—has increased dramatically, and a number of reports have suggested that these better defined, more homogeneous constructs exhibit improved performance in vivo compared to their randomly modified cousins. In this two-part review, we seek to provide an overview of the various methods that have been developed to create site-specifically modified immunoconjugates for positron emission tomography, single photon emission computed tomography, and fluorescence imaging. We will begin with an introduction to the structure of antibodies and antibody fragments. This is followed by the core of the work: sections detailing the four different approaches to site-specific modification strategies based on cysteine residues, glycans, peptide tags, and unnatural amino acids. These discussions will be divided into two installments: cysteine residues and glycans will be detailed in Part 1 of the review, while peptide tags and unnatural amino acids will be addressed in Part 2. Ultimately, we sincerely hope that this review fosters interest and enthusiasm for site-specific immunoconjugates within the nuclear medicine and molecular imaging communities

Identifying maltreatment in infants and young children presenting with fractures: does age matter?

Objectives Child abuse is a significant cause of morbidity and mortality in preverbal children who cannot explain their injuries. Fractures are among the most common injuries associated with abuse but of themselves fractures may not be recognized as abusive until a comprehensive child abuse evaluation is completed, often prompted by other signs or subjective features. We sought to determine which children presenting with rib or long-bone fractures should undergo a routine abuse evaluation based on age. Methods A systematic review searching Ovid, PubMed/Medline, Scopus, and CINAHL from 1980 to 2020 was performed. An evidence-based framework was generated by a consensus panel and applied to the results of the systematic review to form recommendations. Fifteen articles were suitable for final analysis. Results Studies with comparable age ranges of subjects and sufficient evidence to meet the determination of abuse standard for pediatric patients with rib, humeral, and femoral fractures were identified. Seventy-seven percent of children presenting with rib fractures aged less than 3 years were abused; when those involved in motor vehicle collisions were excluded, 96% were abused. Abuse was identified in 48% of children less than 18 months with humeral fractures. Among those with femoral fractures, abuse was diagnosed in 34% and 25% of children aged less than 12 and 18 months, respectively. Conclusion Among children who were not in an independently verified incident, the authors strongly recommend routine evaluation for child abuse, including specialty child abuse consultation, for: 1) children aged less than 3 years old presenting with rib fractures and 2) children aged less than 18 months presenting with humeral or femoral fractures (Level of Evidence: III Review)

Identifying Maltreatment in Infants and Young Children Presenting With Fractures: Does Age Matter?

Objectives Child abuse is a significant cause of morbidity and mortality in preverbal children who cannot explain their injuries. Fractures are among the most common injuries associated with abuse but of themselves fractures may not be recognized as abusive until a comprehensive child abuse evaluation is completed, often prompted by other signs or subjective features. We sought to determine which children presenting with rib or long-bone fractures should undergo a routine abuse evaluation based on age. Methods A systematic review searching Ovid, PubMed/Medline, Scopus, and CINAHL from 1980 to 2020 was performed. An evidence-based framework was generated by a consensus panel and applied to the results of the systematic review to form recommendations. Fifteen articles were suitable for final analysis. Results Studies with comparable age ranges of subjects and sufficient evidence to meet the determination of abuse standard for pediatric patients with rib, humeral, and femoral fractures were identified. Seventy-seven percent of children presenting with rib fractures aged less than 3 years were abused; when those involved in motor vehicle collisions were excluded, 96% were abused. Abuse was identified in 48% of children less than 18 months with humeral fractures. Among those with femoral fractures, abuse was diagnosed in 34% and 25% of children aged less than 12 and 18 months, respectively. Conclusion Among children who were not in an independently verified incident, the authors strongly recommend routine evaluation for child abuse, including specialty child abuse consultation, for: 1) children aged less than 3 years old presenting with rib fractures and 2) children aged less than 18 months presenting with humeral or femoral fractures (Level of Evidence: III Review)

Evolution of Investigating Informed Assent Discussions about CPR in Seriously Ill Patients

ContextOutcomes after cardiopulmonary resuscitation (CPR) remain poor. We have spent 10 years investigating an "informed assent" (IA) approach to discussing CPR with chronically ill patients/families. IA is a discussion framework whereby patients extremely unlikely to benefit from CPR are informed that unless they disagree, CPR will not be performed because it will not help achieve their goals, thus removing the burden of decision-making from the patient/family, while they retain an opportunity to disagree.ObjectivesDetermine the acceptability and efficacy of IA discussions about CPR with older chronically ill patients/families.MethodsThis multi-site research occurred in three stages. Stage I determined acceptability of the intervention through focus groups of patients with advanced COPD or malignancy, family members, and physicians. Stage II was an ambulatory pilot randomized controlled trial (RCT) of the IA discussion. Stage III is an ongoing phase 2 RCT of IA versus attention control in in patients with advanced chronic illness.ResultsOur qualitative work found the IA approach was acceptable to most patients, families, and physicians. The pilot RCT demonstrated feasibility and showed an increase in participants in the intervention group changing from "full code" to "do not resuscitate" within two weeks after the intervention. However, Stages I and II found that IA is best suited to inpatients. Our phase 2 RCT in older hospitalized seriously ill patients is ongoing; results are pending.ConclusionsIA is a feasible and reasonable approach to CPR discussions in selected patient populations

Early probiotic supplementation and the risk of celiac disease in children at genetic risk

Abstract Probiotics are linked to positive regulatory effects on the immune system. The aim of the study was to examine the association between the exposure of probiotics via dietary supplements or via infant formula by the age of 1 year and the development of celiac disease autoimmunity (CDA) and celiac disease among a cohort of 6520 genetically susceptible children. Use of probiotics during the first year of life was reported by 1460 children. Time-to-event analysis was used to examine the associations. Overall exposure of probiotics during the first year of life was not associated with either CDA (n = 1212) (HR 1.15; 95%CI 0.99, 1.35; p = 0.07) or celiac disease (n = 455) (HR 1.11; 95%CI 0.86, 1.43; p = 0.43) when adjusting for known risk factors. Intake of probiotic dietary supplements, however, was associated with a slightly increased risk of CDA (HR 1.18; 95%CI 1.00, 1.40; p = 0.043) compared to children who did not get probiotics. It was concluded that the overall exposure of probiotics during the first year of life was not associated with CDA or celiac disease in children at genetic risk

Time to Peak Glucose and Peak C-Peptide During the Progression to Type 1 Diabetes in the Diabetes Prevention Trial and TrialNet Cohorts

OBJECTIVE To assess the progression of type 1 diabetes using time to peak glucose or C-peptide during oral glucose tolerance tests (OGTTs) in autoantibody-positive relatives of people with type 1 diabetes. RESEARCH DESIGN AND METHODS We examined 2-h OGTTs of participants in the Diabetes Prevention Trial Type 1 (DPT-1) and TrialNet Pathway to Prevention (PTP) studies. We included 706 DPT-1 participants (mean ± SD age, 13.84 ± 9.53 years; BMI Z-score, 0.33 ± 1.07; 56.1% male) and 3,720 PTP participants (age, 16.01 ± 12.33 years; BMI Z-score, 0.66 ± 1.3; 49.7% male). Log-rank testing and Cox regression analyses with adjustments (age, sex, race, BMI Z-score, HOMA-insulin resistance, and peak glucose/C-peptide levels, respectively) were performed. RESULTS In each of DPT-1 and PTP, higher 5-year diabetes progression risk was seen in those with time to peak glucose >30 min and time to peak C-peptide >60 min (P < 0.001 for all groups), before and after adjustments. In models examining strength of association with diabetes development, associations were greater for time to peak C-peptide versus peak C-peptide value (DPT-1: χ2 = 25.76 vs. χ2 = 8.62; PTP: χ2 = 149.19 vs. χ2 = 79.98; all P < 0.001). Changes in the percentage of individuals with delayed glucose and/or C-peptide peaks were noted over time. CONCLUSIONS In two independent at-risk populations, we show that those with delayed OGTT peak times for glucose or C-peptide are at higher risk of diabetes development within 5 years, independent of peak levels. Moreover, time to peak C-peptide appears more predictive than the peak level, suggesting its potential use as a specific biomarker for diabetes progression

Multi-phenotype analyses of hemostatic traits with cardiovascular events reveal novel genetic associations

Background: Multi-phenotype analysis of genetically correlated phenotypes can increase the statistical power to detect loci associated with multiple traits, leading to the discovery of novel loci. This is the first study to date to comprehensively analyze the shared genetic effects within different hemostatic traits, and between these and their associated disease outcomes. Objectives: To discover novel genetic associations by combining summary data of correlated hemostatic traits and disease events. Methods: Summary statistics from genome wide-association studies (GWAS) from seven hemostatic traits (factor VII [FVII], factor VIII [FVIII], von Willebrand factor [VWF] factor XI [FXI], fibrinogen, tissue plasminogen activator [tPA], plasminogen activator inhibitor 1 [PAI-1]) and three major cardiovascular (CV) events (venous thromboembolism [VTE], coronary artery disease [CAD], ischemic stroke [IS]), were combined in 27 multi-trait combinations using metaUSAT. Genetic correlations between phenotypes were calculated using Linkage Disequilibrium Score Regression (LDSC). Newly associated loci were investigated for colocalization. We considered a significance threshold of 1.85 × 10−9 obtained after applying Bonferroni correction for the number of multi-trait combinations performed (n = 27). Results: Across the 27 multi-trait analyses, we found 4 novel pleiotropic loci (XXYLT1, KNG1, SUGP1/MAU2, TBL2/MLXIPL) that were not significant in the original individual datasets, were not described in previous GWAS for the individual traits, and that presented a common associated variant between the studied phenotypes. Conclusions: The discovery of four novel loci contributes to the understanding of the relationship between hemostasis and CV events and elucidate common genetic factors between these traits