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Paul J Tiseo,1 Haobo Ren,2 Scott Mellis3 1Pharmacovigilance Operations and Risk Management, Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA; 2Biostatitics, Regeneron Pharmaceuticals, Inc., Basking Ridge, NJ, USA; 3Translational Medicine and Predictive Medicine, Regeneron Pharmaceuticals, Inc., Tarrytown, NY, USA Objective: To evaluate the efficacy and safety of subcutaneously administered fasinumab (REGN475), a nerve growth factor-neutralizing antibody, in patients with acute sciatic pain receiving standard of care therapy. Methods: This was a double-blind, parallel-group, proof-of-concept study. Patients with unilateral, moderate-to-severe sciatic pain of 2–16 weeks' duration were randomized to a subcutaneous dose of placebo (n=51), fasinumab 0.1 mg/kg (n=53), or 0.3 mg/kg (n=53); follow-up was 12 weeks. Pain was assessed in a daily diary using a numerical rating scale (NRS) (0= no pain, 10= worst pain) for average and worst leg and back pain. The primary efficacy end point was the area under the curve of NRS scores for average leg pain from baseline to week 4. Key secondary end points included changes in average and worst leg and back pain from baseline to the end of week 4 and to each weekly study visit. Patient functioning (Oswestry Disability Index) and concomitant analgesic use were also assessed. Safety and tolerability were evaluated by treatment-emergent adverse events (TEAEs). Results: Demographic and clinical characteristics were similar among the treatment groups; 141 (88.7%) patients completed the study. For the primary end point, mean ± standard deviation area under the curve values from baseline to week 4 were not significantly different between placebo (96.8±6.0) and fasinumab 0.1 mg/kg (112.7±58.3; P=0.0610) or fasinumab 0.3 mg/kg (112.4±55.8; P=0.0923). All secondary efficacy end points of changes in pain and function demonstrated responses that were similar between placebo and fasinumab groups. Incidence of TEAEs was 45.1%, 50.9%, and 64.8% in the placebo, fasinumab 0.1mg/kg, and fasinumab 0.3 mg/kg groups, respectively. The most commonly reported TEAEs included paresthesia, arthralgia, pain in extremity, and headache. Conclusion: Administration of fasinumab provided no significant clinical benefit compared with placebo for the pain or functional limitations associated with acute sciatica. Fasinumab was generally well tolerated and incidence of TEAEs appeared to be dose related. Keywords: fasinumab, monoclonal antibody, nerve growth factor, sciatica, lumbar radiculopathy

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare disorder characterized by the deposition of bone in soft tissues, known as heterotopic ossification (HO). This post hoc analysis compared the performance of two imaging modalities for the detection and volumetric measurement of new HO lesions. LUMINA-1, a phase 2, randomized, double-blind study (NCT03188666), evaluated the safety and efficacy of garetosmab, an anti-activin A antibody, versus placebo in adult patients with FOP. From baseline through to week 28, 18 F-labeled sodium fluoride positron emission tomography (PET)/X-ray computed tomography (CT) and CT-only scans prospectively acquired during the initial placebo-controlled period of the study were independently reviewed by two sets of fixed blinded readers plus an adjudicator for the presence and volume of new HO lesions. The number of patients with new lesions was 14/44 (31.8 %) and 12/44 (27.3 %) as detected by PET/CT and CT only, respectively. The aggregate number/volume of new lesions were very similar both for the placebo and the garetosmab group between PET/CT (27/245.0 cm 3 and 3/21.3 cm 3 , respectively) and CT only (37/261.8 cm 3 and 1/0.1 cm 3 , respectively). The mean (standard deviation) number of new lesions per patient by PET/CT through week 28 was 0.68 (1.57) versus 0.86 (1.95) as detected by CT only. Through week 28, the mean (standard deviation) volume of new lesions per patient detected by PET/CT was 6.05 (14.88) cm 3 versus 5.94 (21.13) cm 3 by CT only. Moderate agreement between PET/CT and CT-only detection was observed when identifying patients with new lesions, with a kappa coefficient of 0.46 (standard error, 0.146; 95 % confidence interval, 0.17-0.74). CT-only imaging showed similar performance to PET/CT in the detection and characterization of new HO lesions. CT-only imaging therefore is a viable option for the assessment of therapies on new HO in patients with FOP., Competing Interests: Declaration of competing interest DGT, JM, ANE, KM, BJM, GAH, and SM are employees and stockholders of Regeneron Pharmaceuticals. Inc., (Copyright © 2024. Published by Elsevier Inc.)

Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare disorder, characterized by progressive heterotopic ossification (HO) and painful soft-tissue inflammatory flare-ups. This was a post hoc analysis from a phase 2 (NCT03188666) trial in which adults with FOP received intravenous anti-activin A antibody garetosmab 10 mg/kg or placebo every 4 wk over 28 wk (Period 1), followed by a 28-wk open-label treatment and extension (Periods 2 and 3). Here we describe flare-ups, their relationship to new HO lesions, and the impact of garetosmab on flare-ups. Volume of new HO lesions was measured by CT. Patient-reported flare-ups were defined by any 2 of the following: new onset of pain, swelling, joint stiffness, decrease in movement, or perceived presence of HO. Flare-ups were experienced by 71% (17/24) of placebo-treated patients, 59% (10/17) of whom developed a new HO lesion irrespective of flare-up location; 24% of flare-ups location-matched new HO lesions. Twenty-nine new HO lesions occurred in the placebo cohort by week 28, of which 12 (41%) occurred in the same location as new or ongoing flare-ups. A higher volume of newly formed heterotopic bone (week 28) occurred in placebo-treated patients who had experienced a prior flare-up vs those without (median [Q1:Q3] of 16.6 [12.0:31.1] vs 3.2 cm3). Garetosmab was previously shown to decrease patient-reported flare-up frequency in Period 1; here, garetosmab reduced the median (Q1:Q3) duration of patient-reported flares (15.0 [6.0:82.0] vs 48.0 [15.0:1.00] d) and the severity of flare-ups vs placebo. Frequency of corticosteroid use was numerically reduced in those treated with garetosmab (40.0%) vs placebo (58.3%). In this analysis, 71% of placebo-treated adults with FOP experienced flare-ups over 28 wk, which were associated with an increased volume of newly formed heterotopic bone. Garetosmab reduced the severity and duration of flare-ups, with effects sustained during the entire trial., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research.)

Introduction: Radiological imaging has played an important role in diagnostic medicine for over a century, though it is known to contribute to dermatological conditions, cataracts, and cancer. The associated risk of harm has led to the introduction of protective regulations around the world. Present-day NHS clinicians are increasingly requesting and relying on diagnostic imaging. Knowledge surrounding the radiation doses of common radiological investigations and the associated risks is imperative, and on a global level has been found to be inadequate. Consequently, there is a need for the formal inclusion of teaching within training programmes., Aims/objectives: This prospective audit aims to establish the knowledge of radiation doses and risks of common radiological investigations of both medical students and referrers within four NHS Health Boards based in the North of Scotland. It also seeks to establish prior teaching and the preference for further educational interventions., Audit Standard: Referrers should have adequate knowledge of radiation doses and the risks associated with common radiological investigations., Audit Target: The standard should be achieved by 90% of referrers., Methods: A 19-question online survey was devised to include subjective and objective questions on ionising radiation awareness, education preference, and respondent demographics, based on RCR (Royal College of Radiologists) audit criteria and previous studies. Data collection was conducted between the 22/02/23 to the 22/03/2023 and the questionnaire was distributed to senior medical students and radiological referrers of different grades within NHS Grampian, NHS Highland, NHS Shetland, and NHS Orkney. A descriptive analysis of the data was undertaken using Microsoft Excel Version 16.71., Results: Two hundred eight questionnaires were completed. 22.11% (n = 46) of the sample population had received no prior teaching on the topic of ionising radiation. Over half of the respondents (51.92%, n = 108) rated the importance of radiation risks as either important or extremely important, with 69.71% (n = 145) of participants rating their perceived knowledge as limited or average. Most correctly identified that a CT scan (n = 203), PET-CT scan (n = 199) and a chest x-ray (n = 196) exposed patients to ionising radiation. A small proportion of the participants incorrectly thought that an MRI scan (n = 21) and an ultrasound scan (n = 2) involved ionising radiation. The results obtained failed to meet the RCR audit target, which states that 90% of doctors should be aware of common radiological doses. It was observed that only 17.79% (n = 37) of survey respondents scored over 50% in the knowledge assessment, with the median knowledge score of the whole cohort being 2.5 out of 9 (27.78%). Respondents who had prior teaching on the topic performed better those who had no prior teaching, with average scores of 3.19 (35.44%) and 2.04 (22.67%) respectively. Senior clinicians performed better when compared to junior clinicians and medical students., Conclusion & Future Recommendations: This audit found that the knowledge of radiation risks within the North of Scotland in the selected sample population was insufficient across all levels of the clinical team. Further, continuous education around the topic and future audit opportunities may help to optimise knowledge and training., (© 2024. The Author(s).)

There is an urgent need for increased understanding of COVID-19 and strategies for its prevention, treatment, and mitigation. All participants in the research enterprise, including institutional review boards, have an ethical duty to protect participants and ensure that the benefits gained from such research do not conflict with the core principles that guided researchers prior to the pandemic. In this review, we discuss the ethical issues surrounding initiation and conduct of clinical trials, focusing on novel COVID-19 therapeutic, vaccine, or biospecimen research, using the principles of autonomy, beneficence, and justice. We discuss strategies to manage the practical challenges associated with the conduct of clinical trials, with an emphasis on maintaining the rights and welfare of research participants., Competing Interests: RV, KC, and SM are employees of and own stock in Regeneron Pharmaceuticals Inc. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Vitti, Vitti, Chu and Mellis.)

Objectives: Complement activation has been implicated in COVID-19 pathogenesis. This study aimed to assess the levels of complement activation products and full-length proteins in hospitalized patients with COVID-19, and evaluated whether complement pathway markers are associated with outcomes., Methods: Longitudinal measurements of complement biomarkers from 89 hospitalized adult patients, grouped by baseline disease severity, enrolled in an adaptive, phase 2/3, randomized, double-blind, placebo-controlled trial and treated with intravenous sarilumab (200 mg or 400 mg) or placebo (NCT04315298), were performed. These measurements were then correlated with clinical and laboratory parameters., Results: All complement pathways were activated in hospitalized patients with COVID-19. Alternative pathway activation was predominant earlier in the disease course. Complement biomarkers correlated with multiple variables of multi-organ dysfunction and inflammatory injury. High plasma sC5b-9, C3a, factor Bb levels, and low mannan-binding lectin levels were associated with increased mortality. Sarilumab treatment showed a modest inhibitory effect on complement activation. Moreover, sera from patients spontaneously deposited C5b-9 complex on the endothelial surface ex vivo, suggesting a microvascular thrombotic potential., Conclusion: These results advance our understanding of COVID-19 disease pathophysiology and demonstrate the importance of specific complement pathway components as prognostic biomarkers in COVID-19., Competing Interests: Declaration of competing interest All the authors are employees of Regeneron Pharmaceuticals, Inc. and own stock or stock options., (Copyright © 2023 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Introduction: Identifying risk factors for progression to severe COVID-19 requiring urgent medical visits and hospitalizations (UMVs) among patients initially diagnosed in the outpatient setting may help inform patient management. The objective of this study was to estimate the incidence of and risk factors for COVID-19-related UMVs after outpatient COVID-19 diagnosis or positive SARS-CoV-2 test., Methods: Data for this retrospective cohort study were from the Optum ® de-identified COVID-19 Electronic Health Record database from June 1 to December 9, 2020. Adults with first COVID-19 diagnosis or positive SARS-CoV-2 test in outpatient settings were identified. Cumulative incidence function analysis stratified by risk factors was used to estimate the 30-day incidence of COVID-19-related UMVs. Competing risk regression models were used to derive adjusted hazard ratios (aHR) and 95% confidence intervals (95% CI) for factors associated with UMVs., Results: Among 206,741 patients [58.8% female, 77.5% non-Hispanic Caucasian, mean (SD) age: 46.7 (17.8) years], the 30-day incidence was 9.4% (95% CI 9.3-9.6) for COVID-19-related emergency room (ER)/urgent care (UC)/hospitalizations and 3.8% (95% CI 3.7-3.9) for COVID-19-related hospitalizations. Likelihood of hospitalization increased with age and body mass index, with age the strongest risk factor (aHR 5.61; 95% CI 4.90-6.32 for patients ≥ 85 years). Increased likelihood of hospitalization was observed for first presentation in the ER/UC vs. non-ER/UC outpatient settings (aHR 2.35; 95% CI 2.22-2.47) and prior all-cause hospitalization (aHR 1.90; 95% CI 1.79-2.00). Clinical risk factors of hospitalizations included pregnancy, uncontrolled diabetes, chronic obstructive pulmonary disease, chronic kidney disease, and autoimmune disease. A study limitation is that data on COVID-19 severity and symptoms were not captured., Conclusion: Predictors of COVID-19-related UMVs include older age, obesity, and several comorbidities. These findings may inform patient management and resource allocation following outpatient COVID-19 diagnosis.

Background: Hypertriglyceridemia is associated with increased cardiovascular risk and may be caused by impaired lipoprotein clearance. Angiopoietin-like protein 3 (ANGPTL3) inhibits lipoprotein lipase activity, increasing triglycerides and other lipids. Evinacumab, an ANGPTL3 inhibitor, reduced triglycerides in healthy human volunteers and in homozygous familial hypercholesterolemic individuals. Results from 2 Phase 1 studies in hypertriglyceridemic subjects are reported here., Methods: Subjects with triglycerides >150 but ≤450 mg/dL and low-density lipoprotein cholesterol ≥100 mg/dL (n=83 for single ascending dose study [SAD]; n=56 for multiple ascending dose study [MAD]) were randomized 3:1 to evinacumab:placebo. SAD subjects received evinacumab subcutaneously at 75/150/250 mg, or intravenously at 5/10/20 mg/kg, monitored up to day 126. MAD subjects received evinacumab subcutaneously at 150/300/450 mg once weekly, 300/450 mg every 2 weeks, or intravenously at 20 mg/kg once every 4 weeks up to day 56 with 6 months of follow-up. The primary outcomes were incidence and severity of treatment-emergent adverse events. Efficacy analyses included changes in triglycerides and other lipids over time., Results: In the SAD, 32 (51.6%) versus 9 (42.9%) subjects on evinacumab versus placebo reported treatment-emergent adverse events. In the MAD, 21 (67.7%) versus 9 (75.0%) subjects on subcutaneously evinacumab versus placebo and 6 (85.7%) versus 1 (50.0%) on intravenously evinacumab versus placebo reported treatment-emergent adverse events. No serious treatment-emergent adverse events or events leading to death or treatment discontinuation were reported. Elevations in alanine aminotransferase (7 [11.3%] SAD), aspartate aminotransferase (4 [6.5%] SAD), and creatinine phosphokinase (2 [3.2%) SAD, 1 [14.3%] MAD) were observed with evinacumab (none in the placebo groups), which were single elevations and were not dose-related. Dose-dependent reductions in triglycerides were observed in both studies, with maximum reduction of 76.9% at day 3 with 10 mg/kg intravenously (P<0.0001) in the SAD and of 83.1% at day 2 with 20 mg/kg intravenously once every 4 weeks (P=0.0003) in the MAD. Significant reductions in other lipids were observed with most evinacumab doses versus placebo., Conclusion: Evinacumab was well-tolerated in 2 Phase 1 studies. Lipid changes in hypertriglyceridemic subjects were similar to those observed with ANGPTL3 loss-of-function mutations. Because the latter is associated with reduced cardiovascular risk, ANGPTL3 inhibition may improve clinical outcomes., Clinical Trial Registration: https://www.clinicaltrials.gov. Unique identifiers: NCT01749878 and NCT02107872.

The DiscovEHR collaboration between the Regeneron Genetics Center and Geisinger Health System couples high-throughput sequencing to an integrated health care system using longitudinal electronic health records (EHRs). We sequenced the exomes of 50,726 adult participants in the DiscovEHR study to identify ~4.2 million rare single-nucleotide variants and insertion/deletion events, of which ~176,000 are predicted to result in a loss of gene function. Linking these data to EHR-derived clinical phenotypes, we find clinical associations supporting therapeutic targets, including genes encoding drug targets for lipid lowering, and identify previously unidentified rare alleles associated with lipid levels and other blood level traits. About 3.5% of individuals harbor deleterious variants in 76 clinically actionable genes. The DiscovEHR data set provides a blueprint for large-scale precision medicine initiatives and genomics-guided therapeutic discovery., (Copyright © 2016, American Association for the Advancement of Science.)

Background: Patients with PCSK9 gene gain of function (GOF) mutations have a rare form of autosomal dominant hypercholesterolemia. However, data examining their clinical characteristics and geographic distribution are lacking. Furthermore, no randomized treatment study in this population has been reported., Methods and Results: We compiled clinical characteristics of PCSK9 GOF mutation carriers in a multinational retrospective, cross-sectional, observational study. We then performed a randomized placebo-phase, double-blind study of alirocumab 150 mg administered subcutaneously every 2 weeks to 13 patients representing 4 different PCSK9 GOF mutations with low-density lipoprotein cholesterol (LDL-C) ≥70 mg/dL on their current lipid-lowering therapies at baseline. Observational study: among 164 patients, 16 different PCSK9 GOF mutations distributed throughout the gene were associated with varying severity of untreated LDL-C levels. Coronary artery disease was common (33%; average age of onset, 49.4 years), and untreated LDL-C concentrations were higher compared with matched carriers of mutations in the LDLR (n=2126) or apolipoprotein B (n=470) genes. Intervention study: in PCSK9 GOF mutation patients randomly assigned to receive alirocumab, mean percent reduction in LDL-C at 2 weeks was 62.5% (P<0.0001) from baseline, 53.7% compared with placebo-treated PCSK9 GOF mutation patients (P=0.0009; primary end point). After all subjects received 8 weeks of alirocumab treatment, LDL-C was reduced by 73% from baseline (P<0.0001)., Conclusions: PCSK9 GOF mutation carriers have elevated LDL-C levels and are at high risk of premature cardiovascular disease. Alirocumab, a PCSK9 antibody, markedly lowers LDL-C levels and seems to be well tolerated in these patients., Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique Identifier: NCT01604824., (© 2015 The Authors.)

Background: Proprotein convertase subtilisin/kexin 9 (PCSK9), one of the serine proteases, binds to low-density lipoprotein (LDL) receptors, leading to their accelerated degradation and to increased LDL cholesterol levels. We report three phase 1 studies of a monoclonal antibody to PCSK9 designated as REGN727/SAR236553 (REGN727)., Methods: In healthy volunteers, we performed two randomized, single ascending-dose studies of REGN727 administered either intravenously (40 subjects) or subcutaneously (32 subjects), as compared with placebo. These studies were followed by a randomized, placebo-controlled, multiple-dose trial in adults with heterozygous familial hypercholesterolemia who were receiving atorvastatin (21 subjects) and those with nonfamilial hypercholesterolemia who were receiving treatment with atorvastatin (30 subjects) (baseline LDL cholesterol, >100 mg per deciliter [2.6 mmol per liter]) or a modified diet alone (10 subjects) (baseline LDL cholesterol, >130 mg per deciliter [3.4 mmol per liter]). REGN727 doses of 50, 100, or 150 mg were administered subcutaneously on days 1, 29, and 43. The primary outcome for all studies was the occurrence of adverse events. The principal secondary outcome was the effect of REGN727 on the lipid profile., Results: Among subjects receiving REGN727, there were no discontinuations because of adverse events. REGN727 significantly lowered LDL cholesterol levels in all the studies. In the multiple-dose study, REGN727 doses of 50, 100, and 150 mg reduced measured LDL cholesterol levels in the combined atorvastatin-treated populations to 77.5 mg per deciliter (2.00 mmol per liter), 61.3 mg per deciliter (1.59 mmol per liter), and 53.8 mg per deciliter (1.39 mmol per liter), for a difference in the change from baseline of -39.2, -53.7, and -61.0 percentage points, respectively, as compared with placebo (P<0.001 for all comparisons)., Conclusions: In three phase 1 trials, a monoclonal antibody to PCSK9 significantly reduced LDL cholesterol levels in healthy volunteers and in subjects with familial or nonfamilial hypercholesterolemia. (Funded by Regeneron Pharmaceuticals and Sanofi; ClinicalTrials.gov numbers, NCT01026597, NCT01074372, and NCT01161082.).

Background: Transforming growth factor (TGF)-β is a multifunctional peptide that is important in T-cell activation and cardiovascular remodeling, both of which are important features of Kawasaki disease (KD). We postulated that variation in TGF-β signaling might be important in KD susceptibility and disease outcome., Methods and Results: We investigated genetic variation in 15 genes belonging to the TGF-β pathway in a total of 771 KD subjects of mainly European descent from the United States, the United Kingdom, Australia, and the Netherlands. We analyzed transcript abundance patterns using microarray and reverse transcriptase-polymerase chain reaction for these same genes, and measured TGF-β2 protein levels in plasma. Genetic variants in TGFB2, TGFBR2, and SMAD3 and their haplotypes were consistently and reproducibly associated with KD susceptibility, coronary artery aneurysm formation, aortic root dilatation, and intravenous immunoglobulin treatment response in different cohorts. A SMAD3 haplotype associated with KD susceptibility replicated in 2 independent cohorts and an intronic single nucleotide polymorphism in a separate haplotype block was also strongly associated (A/G, rs4776338) (P=0.000022; odds ratio, 1.50; 95% confidence interval, 1.25 to 1.81). Pathway analysis using all 15 genes further confirmed the importance of the TGF-β pathway in KD pathogenesis. Whole-blood transcript abundance for these genes and TGF-β2 plasma protein levels changed dynamically over the course of the illness., Conclusions: These studies suggest that genetic variation in the TGF-β pathway influences KD susceptibility, disease outcome, and response to therapy, and that aortic root and coronary artery Z scores can be used for phenotype/genotype analyses. Analysis of transcript abundance and protein levels further support the importance of this pathway in KD pathogenesis.

Intravenous immunoglobulin (IVIG)-resistant Kawasaki disease (KD) patients comprise at least 20% of treated patients and are at high risk for coronary artery abnormalities. If identified early in the course of the disease, such patients may benefit from additional anti-inflammatory therapy. The aim of this study was to compare the transcript abundance between IVIG resistant and -responsive KD patients, to identify biomarkers that might differentiate between these two groups and to generate new targets for therapies in IVIG resistant KD patients. We compared the transcript abundance profiles of whole-blood RNA on Agilent arrays from acute and convalescent KD subjects and age-similar, healthy controls. KD subjects were stratified as IVIG resistant or -responsive based on response to initial IVIG therapy. Transcript abundance was higher for IL-1 pathway genes (IL-1 receptor, interleukin receptor associated kinase, p38 mitogen-activated protein kinase), and MMP-8. These findings point to candidate biomarkers that may predict IVIG resistance in acute KD patients. The results also underscore the importance of the IL-1 pathway as a mediator of inflammation in KD and suggest that IL-1 or its receptor may be reasonable targets for therapy, particularly for IVIG resistant patients., (Copyright 2010 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)

Rilonacept is a dimeric fusion protein consisting of the extracellular domains of interleukin (IL)-1 type 1 receptor and IL-1 receptor accessory protein joined to the constant region (Fc) of human immunoglobulin G1. By incorporating both components of the IL-1 binding complex, rilonacept is able to tightly bind IL-1 with picomolar affinity. Although early clinical results in rheumatoid arthritis (RA) suggested that RA is not primarily an IL-1-driven disease, the discovery that the rare genetic conditions called cryopyrin-associated periodic syndromes (CAPS) were caused by overproduction of IL-1 led to clinical development and approval for these conditions. An assay that detects rilonacept:IL-1 complexes in plasma is helping to identify new indications, such as gout, in which IL-1 overproduction plays a key pathogenic role. The development of rilonacept for CAPS was achieved through collaboration between the pharmaceutical industry, academia, and government agencies, and demonstrates that knowledge gleaned in orphan indications can inform drug development for more common and heterogeneous diseases.

We report the isolation of a novel human POU domain encoding gene named RDC-1. The POU domain of the RDC-1 encoded protein is highly related to the POU domain potentially encoded by the rat brain-3 sequence and to that of the Drosophila I-POU protein; outside of the POU region, RDC-1 is unrelated to any previously characterized protein. The RDC-1 gene is expressed almost exclusively in normal tissues and transformed cells of neural origin. In the developing mouse and human fetus, RDC-1 is expressed in a spatially and temporally restricted pattern that suggests a critical role in the differentiation of neuronal tissues. In addition, RDC-1 is expressed in a unique subset of tumors of the peripheral nervous system including neuroepitheliomas and Ewing's sarcomas but not neuroblastomas. Based on its unique structural characteristics and expression pattern, we discuss potential functions for the RDC-1 protein.

A rapid method for the fractionation of anionic oligosaccharide and glycopeptide species on the basis of net carbohydrate content utilizing high-performance liquid chromatography has been developed. Amine-bearing bonded-phase columns are eluted with a mobile phase consisting of a water:acetonitrile gradient containing 3% acetic acid titrated to pH 5.5 with triethylamine. Phosphorylated and sialylated oligosaccharides within various charge classes differing in their hexose or hexosamine contents but bearing the same number of anionic species can be resolved without prior removal of the anionic moieties. Glycopeptides containing at least as many as six amino acids are also well fractionated on the basis of carbohydrate content. A variety of detection methods may be used and sensitivity in the subnanomole range is possible with fluorescent or radiolabeling techniques. This method offers a significant improvement in the rapidity and resolution attainable for the size fractionation of anionic complex carbohydrates.

Our recent studies have focused on the organization of immunoglobulin genes in mice and humans and the mechanism and control of the recombination events that are involved in their assembly and expression. This report describes our progress in this area with particular focus on elucidating factors that influence the generation of the antibody repertoire in normal and diseased states. We present a detailed analysis of the organization of the human VH locus, studies that help to elucidate the nature of the recombination defect in mice with severe combined immunodeficiency, and studies of transgenic mice that focus on the mechanism that regulates tissue-specific variable region gene assembly. In addition, we also characterize mechanisms that control the heavy chain class-switch process. Although the latter process apparently involve a recombination system distinct from that involved in variable region assembly, we find that the two recombination events appear to be controlled by similar mechanisms.