Translational and Regulatory Challenges for Exon Skipping Therapies

Several translational challenges are currently impeding the therapeutic development of antisense-mediated exon skipping approaches for rare diseases. Some of these are inherent to developing therapies for rare diseases, such as small patient numbers and limited information on natural history and interpretation of appropriate clinical outcome measures. Others are inherent to the antisense oligonucleotide (AON)-mediated exon skipping approach, which employs small modified DNA or RNA molecules to manipulate the splicing process. This is a new approach and only limited information is available on long-term safety and toxicity for most AON chemistries. Furthermore, AONs often act in a mutation-specific manner, in which case multiple AONs have to be developed for a single disease. A workshop focusing on preclinical development, trial design, outcome measures, and different forms of marketing authorization was organized by the regulatory models and biochemical outcome measures working groups of Cooperation of Science and Technology Action: "Networking towards clinical application of antisense-mediated exon skipping for rare diseases." The workshop included participants from patient organizations, academia, and members of staff from the European Medicine Agency and Medicine Evaluation Board (the Netherlands). This statement article contains the key outcomes of this meeting.status: publishe

Rates of referable eye disease in the Scottish National Diabetic Retinopathy Screening Programme

Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.Peer reviewedPublisher PD

Progression and Regression: Distinct Developmental Patterns of Diabetic Retinopathy in Patients With Type 2 Diabetes Treated in the Diabetes Care System West-Friesland, the Netherlands

OBJECTIVE: To identify distinct developmental patterns of diabetic retinopathy (DR) and assess the risk factor levels of patients in these clusters. RESEARCH DESIGN AND METHODS: A cohort of 3,343 patients with type 2 diabetes mellitus (T2DM) monitored and treated in the Diabetes Care System West-Friesland, the Netherlands, was followed from 2 to 6 years. Risk factors were measured, and two-field fundus photographs were taken annually and graded according to the EURODIAB study group. Latent class growth modeling was used to identify distinct developmental patterns of DR over time. RESULTS: Five clusters of patients with distinct developmental patterns of DR were identified: A, patients without any signs of DR (88.9%); B, patients with a slow regression from minimal background to no DR (4.9%); C, patients with a slow progression from minimal background to moderate nonproliferative DR (4.0%); D, patients with a fast progression from minimal or moderate nonproliferative to (pre)proliferative or treated DR (1.4%); and E, patients with persistent proliferative DR (0.8%). Patients in clusters A and B were characterized by lower risk factor levels, such as diabetes duration, HbA(1c), and systolic blood pressure compared with patients in progressive clusters (C-E). CONCLUSIONS: Clusters of patients with T2DM with markedly different patterns of DR development were identified, including a cluster with regression of DR. These clusters enable a more detailed examination of the influence of various risk factors on DR

Blood pressure, lipids, and obesity are associated with reteinopathy - The Hoorn study

OBJECTIVE - To study potential risk factors for retinopathy in diabetic and nondiabetic individuals. RESEARCH DESIGN AND METHODS - The Hoorn Study is a population-based study including 2,484 50- to 74-year-old Caucasians. A subsample of 626 individuals stratified by age, sex, and glucose tolerance underwent extensive measurements during 1989-1992, including ophthalmologic examination and two-field 45-degree fundus photography. The prevalence of (diabetic) retinopathy was assessed among individuals with normal glucose metabolism (NGM) and impaired glucose metabolism (IGM) and individuals with newly diagnosed diabetes mellitus (NDM) and known diabetes mellitus (KDM) (new World Health Organization 1999 criteria). RESULTS - The prevalence of retinopathy was 9% in NGM, 11% in IGM, 13% in NDM, and 34% in KDM. Retinopathy worse than minimal nonproliferative diabetic retinopathy was present in 8% in KDM and 0-2% in other glucose categories. The prevalence of retinopathy was positively associated with elevated blood pressure, BMI, cholesterol, and triglyceride serum levels in all glucose categories. The age-, sex-, and glucose metabolism category-adjusted odds ratios were 1.5 (95% CI 1.2-1.9), 1.3 (1.0-1.7), and 1.3 (1.0-1.6) per SD increase of systolic blood pressure, BMI, and total cholesterol concentration, respectively, and 1.2 (1.0-1.5) per 50% increase of triglyceride level. Elevated blood pressure and plasma total and LDL cholesterol levels showed associations with retinal hard exudates. CONCLUSIONS - Retinopathy is a multifactorial microvascular complication, which, apart from hyperglycemia, is associated with blood pressure, lipid concentrations, and BMI

Relationship Between Peer Assessment During Medical School, Dean’s Letter Rankings, and Ratings by Internship Directors

BACKGROUND: It is not known to what extent the dean’s letter (medical student performance evaluation [MSPE]) reflects peer-assessed work habits (WH) skills and/or interpersonal attributes (IA) of students. OBJECTIVE: To compare peer ratings of WH and IA of second- and third-year medical students with later MSPE rankings and ratings by internship program directors. DESIGN AND PARTICIPANTS: Participants were 281 medical students from the classes of 2004, 2005, and 2006 at a private medical school in the northeastern United States, who had participated in peer assessment exercises in the second and third years of medical school. For students from the class of 2004, we also compared peer assessment data against later evaluations obtained from internship program directors. RESULTS: Peer-assessed WH were predictive of later MSPE groups in both the second (F = 44.90, P < .001) and third years (F = 29.54, P < .001) of medical school. Interpersonal attributes were not related to MSPE rankings in either year. MSPE rankings for a majority of students were predictable from peer-assessed WH scores. Internship directors’ ratings were significantly related to second- and third-year peer-assessed WH scores (r = .32 [P = .15] and r = .43 [P = .004]), respectively, but not to peer-assessed IA. CONCLUSIONS: Peer assessment of WH, as early as the second year of medical school, can predict later MSPE rankings and internship performance. Although peer-assessed IA can be measured reliably, they are unrelated to either outcome

DNA fragments of altered electrophoretic mobility in leukemia samples can arise from double-strand DNA breaks at nuclease hypersensitive sites of active genes

Chromosome translocations that disrupt or alter gene function have been implicated in the pathogenesis of a variety of malignancies. Therefore, identification of a translocation breakpoint has become a more important means by which to identify genes involved in cellular transformation. A common site of translocation in myeloid and lymphoid malignancies involves 11q23. One human protooncogene, ETS1, has been localized to this chromosomal segment, and several tumors with 11q23 translocations have been shown to have altered ETS1 DNA migration after restriction enzyme digestion. Two laboratories, however, have recently localized the 11q23 breakpoint region to a small region of DNA telomeric of the CD3 loci, a region at considerable distance from the ETS1 gene locus. Therefore, it is difficult to reconcile the studies that suggest altered migration of fragments associated with ETS1 and lack of a localization of the breakpoint to a region near the ETS1 gene. Recently, in our studies to characterize the promoter/enhancer region of the ETS1 protooncogene, we had the opportunity to analyze DNA from 18 patients with acute leukemia involving chromosome 11q23 aberrations. We were unable to demonstrate rearrangement of the ETS1 gene in this group, thus confirming that the 11q23 breakpoint does not involve ETS1 protooncogene. In one patient, however, a DNA break in the region of the ETS1 promoter was detected reproducibly. This DNA break was mapped to the major DNaseI hypersensitive site in the ETS1 promoter. Mapping from both sides of the break demonstrated that the break must have occurred during processing of the leukemic cells for DNA analysis. Therefore, artifactual DNA breaks can occur at nuclease-hypersensitive sites of active genes. These data suggest that previous reports of chromosomal translocations involving the ETS1 protooncogene may have resulted from DNA breaks at nuclease hypersensitive sites. This mechanism may account for sporadic case reports of altered restriction enzyme fragment migration involving genes that are not ultimately shown to be associated with the chromosome translocation being examined.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30693/1/0000338.pd

Population Pharmacokinetic Modeling of Blood-Brain Barrier Transport of Synthetic Adenosine A 1 Receptor Agonists

ABSTRACT A population pharmacokinetic model is proposed for estimation of the brain distribution clearance of synthetic A 1 receptor agonists in vivo. Rats with permanent venous and arterial cannulas in combination with a microdialysis probe in the striatum received intravenous infusions of 8-methylamino-N 6 -cyclopentyladenosine (MCPA) and 2Ј-deoxyribose-N 6 -cyclopentyladenosine (2Ј-dCPA) (10 mg kg Ϫ1 ). The clearance for transport from blood to the brain was estimated by simultaneous analysis of the blood and extracellular fluid concentrations using a compartmental pharmacokinetic model. The proposed pharmacokinetic model consists of three compartments describing the time course of the concentration in blood in combination with three compartments for the brain extracellular fluid concentrations. The blood clearance was 7.4 Ϯ 0.5 for MCPA and 7.2 Ϯ 1.4 ml min Ϫ1 for 2Ј-dCPA. The in vivo microdialysis recoveries determined by the dynamic-no-net-flux method were independent of time with values of 0.21 Ϯ 0.02 and 0.22 Ϯ 0.01 for MCPA and 2Ј-dCPA, respectively. The values of the intercompartmental clearance for the distribution from blood to brain were 1.9 Ϯ 0.4 versus 1.6 Ϯ 0.3 l min Ϫ1 for MCPA and 2Ј-dCPA, respectively. It is concluded that on basis of the novel six-compartment model precise estimates of the rate of brain distribution are obtained that are independent of eventual differences in systemic exposure. The low brain distribution rates of MCPA and 2Ј-dCPA were consistent with in vitro tests. Furthermore, a slow elimination from the brain compartment was observed, indicating that the duration of central nervous system effects may be much longer than expected on the basis of the terminal half-life in blood. Blood-brain barrier (BBB) transport is a major determinant of the effect of CNS active drugs. This transport is determined by: 1) the morphology and functionality of the brain capillaries and 2) the physicochemical characteristics of the drug. Specifically, the transport of hydrophilic drugs is limited due to the presence of tight junctions between the capillary endothelial cells At present, there are several approaches to the characterization of the BBB transport that can broadly be divided into three categories: 1) in vitro assays, 2) in situ perfusion techniques, and 3) in vivo methods. Blood-brain barrier transport is often studied in vitro in cocultures of brain-capillary-endothelial cells and astrocytes To study drug transport to the brain in vivo, frequently destructive sampling techniques have been applied. Nowadays, intracerebral microdialysis is an established technique for studying the physiology, pharmacology, and pathology o

VizieR Online Data Catalog: 3C388 145, 392, 614, 1400 and 4850MHz images (Brienza+, 2020)

We used a recent dataset obtained on June 26th, 2019, as part of the LOFAR Two-metre Sky Survey (LoTSS, see Shimwell et al., 2019A&A...622A...1S, Cat. J/A+A/622/A1). We observed the source with the Very Large Array (VLA) in A configuration on July 28th 2015 using the P-band receiver centered at 350MHz. We reprocessed the data used by Roettiger et al. (1994ApJ...421L..23R) at 1400MHz and 4850MHz. The data consists of observations in B array at 1400MHz and in C array at 4850MHz. The target was observed for 7 hours at 1400MHz and for 5 hours at 4850MHz. The target was observed with the legacy Giant Metrewave Radio Telescope (GMRT) at 614MHz and 240MHz in dual frequency mode and data were published in Lal et al. (2008MNRAS.390.1105L). The observations were performed on July 29th and 30th, 2005. 3C388 was observed by Chandra on February 9th and 29th, 2004 with the ACIS-I detector (obs ID 4756 and 5295, respectively) and the data were published by Kraft et al. (2006ApJ...639..753K). (2 data files)

Absence of diabetic retinopathy in a patient who has had diabetes mellitus for 69 years, and inadequate glycemic control: case presentation

The main risk factors for the development and progression of diabetic retinopathy (DR) are chronic hyperglycemia, disease duration and systemic blood pressure. So far chronic hyperglycemia is the strongest evidence concerning the risk of developing DR. However there are some patients with poor metabolic control who never develop this diabetic complication. We present a case of a 73-year-old woman with type 1 diabetes mellitus, diagnosed 69 years ago. The patient is 73 years old, with no evidence of DR, despite poor glycemic control and several risk factors for DR. This case suggests the presence of a possible protection factor, which could be genetic