Use of synthetic peptides for identifying biotinylation sites in human histones

Posttranslational modifications of histones play an important role in the regulation of chromatin structure and, hence, gene regulation. Recently, we have identified a novel modification of histones: binding of the vitamin biotin to lysine residues in histones H2A, H3, and H4. Here, we describe a procedure to identify those amino acids that are targets for biotinylation in histones. Briefly, the following analytical sequence is used to identify biotinylation sites: (i) short peptides (<20 amino acids in length) are synthesized chemically; amino acid sequences in the peptides are based on the sequence in a given region of a given histone; (ii) peptides are incubated with biotinidase or holocarboxylase synthetase to conduct enzymatic biotinylation; and (iii) biotin in peptides are probed using streptavidin peroxidase. Amino acid substitutions (e.g., lysine-to-alanine substitutions) in synthetic peptides can be used to corroborate identification of biotinylation sites.Fil: Camporeale, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad de Nebraska - Lincoln; Estados UnidosFil: Chew, Yap Ching. Universidad de Nebraska - Lincoln; Estados UnidosFil: Kueh, Alice. Universidad de Nebraska - Lincoln; Estados UnidosFil: Sarath, Gautam. Universidad de Nebraska - Lincoln; Estados UnidosFil: Zempleni, Janos. Universidad de Nebraska - Lincoln; Estados Unido

Mapping challenges in the accessibility of treatment products for urea cycle disorders: A survey of European healthcare professionals

Current management guidelines for urea cycle disorders (UCDs) offer clear strategies, incorporating both authorized and non-authorized medicinal products (including intravenous formulations and products regulated as food). These varying product categories are subject to specific accessibility challenges related to availability, reimbursement, and pricing. The aim of this study is to identify potential obstacles to optimal UCD treatment implementation in European clinical practice. A survey aimed at metabolic healthcare professionals (HCPs) managing patients with UCDs in Europe was disseminated through the European Reference Network for Hereditary Metabolic Disorders and the European registry and network for intoxication type metabolic diseases. Forty-eight survey responses were collected from 21 European countries. In 16 of these countries, at least one metabolic HCP reported challenges in accessing UCD products. Reimbursement issues were reported for most products (8/10), including both authorized and non-authorized products. Availability-related challenges were also reported for 8/10 products, although unavailability was limited to non-authorized products. Prices impacted accessibility for all authorized products (3/3) and one non-authorized IV product. The accessibility of UCD treatment products varied across Europe, although no clear regional variations could be discerned. Survey data revealed that metabolic HCPs experience challenges in accessing both authorized and non-authorized products for UCD management in the majority of European countries. This indicates that registering unauthorized products may not resolve all issues. Improved reimbursement policies and fair pricing models, as well as (adjusted) authorization procedures may help address these concerns, thereby optimizing treatment access for UCD patients

State of the Art and Consensus Statements by Healthcare Providers, Patients, and Caregivers on Continuous Glucose Monitoring in Liver Glycogen Storage Diseases

Continuous glucose monitoring (CGM) is increasingly used although not officially registered for the management of people living with liver glycogen storage diseases (GSDs). The aims of this study were twofold: (a) to investigate the current experiences of healthcare providers (HCPs), patients, and caregivers using CGM to monitor glucose concentrations in liver GSDs, and (b) to formulate consensus statements. Two web-based questionnaires were distributed, one for HCPs and one for patients and/or their caregivers. The questionnaires collected data on demographics and epidemiology, current use of CGM, and opinions and statements about CGM in GSDs. For the statements, respondents rated their agreement on a 5-point Likert scale, and the consensus level was set at 75%. One Hundred Fourteen HCPs (including 87 physicians and 26 dietitians) from 28 countries responded, representing care of approximately 3800 liver GSD patients. Additionally, 148 GSD patients and/or their caregivers from 21 countries responded, mainly representing GSD Ia (n = 50), GSD Ib (n = 56), GSD III (n = 14), and GSD IX (n = 18). The median age to consider starting to use CGM was 6 and 2 months for HCPs and GSD families, respectively. Out of 16 statements common to the two questionnaires, HCPs and patients/caregivers reached consensus on 12 statements in both groups. Use of CGM is considered standard of care by both HCPs and GSD families, but reimbursement of CGM devices is challenging. Compared to diabetes mellitus, CGM should be applied differently in liver GSDs. Consensus guidelines are warranted on the use of CGM in liver GSDs, both in routine healthcare and in clinical trials