Spontaneous allelic variant in deafness-blindness gene Ush1g resulting in an expanded phenotype

Relationships between novel phenotypic behaviors and specific genetic alterations are often discovered using target-specific, directed mutagenesis or phenotypic selection following chemical mutagenesis. An alternative approach is to exploit deficiencies in DNA repair pathways that maintain genetic integrity in response to spontaneously induced damage. Mice deficient in the DNA glycosylase NEIL1 show elevated spontaneous mutations, which arise from translesion DNA synthesis past oxidatively induced base damage. Several litters of Neil1 knockout mice included animals that were distinguished by their backwards-walking behavior in open-field environments, while maintaining frantic forward movements in their home cage environment. Other phenotypic manifestations included swim test failures, head tilting and circling. Mapping of the mutation that conferred these behaviors showed the introduction of a stop codon at amino acid 4 of the Ush1g gene. Ush1gbw/bw null mice displayed auditory and vestibular defects that are commonly seen with mutations affecting inner-ear hair-cell function, including a complete lack of auditory brainstem responses and vestibular-evoked potentials. As in other Usher syndrome type I mutant mouse lines, hair cell phenotypes included disorganized and split hair bundles, as well as altered distribution of proteins for stereocilia that localize to the tips of row 1 or row 2. Disruption to the bundle and kinocilium displacement suggested that USH1G is essential for forming the hair cell's kinocilial links. Consistent with other Usher type 1 models, Ush1gbw/bw mice had no substantial retinal degeneration compared with Ush1gbw /+ controls. In contrast to previously described Ush1g alleles, this new allele provides the first knockout model for this gene.

A Ketogenic & Low-Protein Diet Slows Retinal Degeneration in rd10 Mice

Purpose

Treatments that delay retinal cell death regardless of genetic causation are needed for inherited retinal degeneration (IRD) patients. The ketogenic diet is a high-fat, low-carbohydrate diet, used to treat epilepsy, and has beneficial effects for neurodegenerative diseases. This study aimed to determine whether the ketogenic diet could slow retinal degeneration.

Methods

Early weaned, rd10 and wild-type (WT) mice were placed on either standard chow, a ketogenic diet, or a ketogenic & low-protein diet. From postnatal day (PD) 23 to PD50, weight and blood β-hydroxybutyrate levels were recorded. Retinal thickness, retinal function, and visual performance were measured via optical coherence tomography, electroretinography (ERG), and optokinetic tracking (OKT). At PD40, serum albumin, rhodopsin protein, and phototransduction gene expression were measured.

Results

Both ketogenic diets elicited a systemic induction of ketosis. However, rd10 mice on the ketogenic & low-protein diet had significant increases in photoreceptor thickness, ERG amplitudes, and OKT thresholds, whereas rd10 mice on the ketogenic diet showed no photoreceptor preservation. In both rd10 and WT mice, the ketogenic & low-protein diet was associated with abnormal weight gain and decreases in serum albumin levels, 27% and 56%, respectively. In WT mice, the ketogenic & low-protein diet was also associated with an ∼20% to 30% reduction in ERG amplitudes.

Conclusions

The ketogenic & low-protein diet slowed retinal degeneration in a clinically relevant IRD model. In WT mice, the ketogenic & low-protein diet was associated with a decrease in phototransduction and serum albumin, which could serve as a protective mechanism in the rd10 model. Although ketosis was associated with protection, its role remains unclear.

Translational Relevance

Neuroprotective mechanisms associated with the ketogenic & low-protein diet have potential to slow retinal degeneration.

[Association between prescription of long-term systemic glucocorticoid therapy associated measures and prescriber's medical speciality]

INTRODUCTION

In order to prevent some glucocorticoid-induced adverse events, adjuvant measures are often associated with prescription of long-term (≥3 months) systemic glucocorticoid therapy. The main objective of this study was to study the association between prescription of these measures and the medical specialty of the prescriber.

METHODS

A cross-sectional study was conducted through the website www.cortisone-info.fr. Patients visiting this website and receiving long-term glucocorticoid therapy were asked to fill a questionnaire asking them, among other things, the specialty of the physician who initiated glucocorticoids and the adjuvant measures they were prescribed at treatment initiation.

RESULTS

In all, 1383 patients answered the questionnaire and 843 (61%) questionnaires were analyzed (women: 70.6%, median age: 59 [44-70] years, current glucocorticoid dosage: 12.5 [5-30] mg/day, maximum dose: 42 [20-60] mg/day). The main prescribers were rheumatologists (30.5%) and internists (17.3%). Most adjuvant measures were heterogeneously prescribed and depended largely on the specialty of the prescribing physician. Some probably unnecessary measures in most patients (potassium supplementation, prevention of peptic ulcer, low-sodium diet) were frequently prescribed while other consensual measures (prevention of osteoporosis, vaccinations) were prescribed to less than half of patients. In multivariable analyses, most of the studied measures were more frequently prescribed by internists than by colleagues of other specialties. Pneumologists more often vaccinated patients against influenza or pneumococcus than their colleagues.

CONCLUSION

Adjuvant measures to long-term glucocorticoid therapy are heterogeneously prescribed. The prescriptions depend largely on the medical specialty of the prescribing physician.

[Glucocorticoid therapy: what is the information sought by patients? Traffic analysis of the website cortisone-info.fr]

INTRODUCTION

About 1% of the general population are receiving systemic glucocorticoids. The information about this treatment sought by patients is unknown.

MATERIALS AND METHODS

The website www.cortisone-info.fr aims to provide therapeutic information about glucocorticoids and glucocorticoid therapy. It was posted on January 16, 2012. The information available on the website is documented and based on the recent medical literature. The website is made of 43 pages divided into five main sections (generalities about glucocorticoids, adverse events, measures associated with glucocorticoid therapy, discontinuation of glucocorticoids and, situations requiring attention). The website traffic between February 1st, 2012 and January 4, 2013 was analyzed using Google Analytics.

RESULTS

During the study period, the website was visited by 67,496 people (average number of visitors per day: 33 in February 2012, 326 in December 2012). The number of page views was 230,496 or an average of 3.5 pages per visitor. Of these 230,496 page views, 145,431 (63.1%) were related to adverse events and 37,722 (16.4%) were related to generalities about glucocorticoids (e.g., what is cortisone? For which disease? How does it work?). Information particularly sought by visitors was related to the diet to follow during glucocorticoid therapy (page accessed 11,946 times), data about what cortisone is (page accessed 11,829 times) and the effects of glucocorticoids on weight (page accessed 10,442 times).

CONCLUSION

Knowledge of glucocorticoid-treated patients' expectations may help physicians to optimize information they give, thereby helping to reduce patients' concerns about glucocorticoids and to improve adherence to the treatment.

Phases of myogenic cell activation and possible role of dermomyotome cells in teleost muscle formation

Present knowledge indicates that fibre recruitment (hyperplasia) in developing teleost fish occurs in three distinct phases. However, the origin and relationship of the myogenic precursors activated during the different phases remains unclear. Here, we address this issue using molecular techniques on embryos and larvae of pearlfish, a large cyprinid species. Results provide comprehensive molecular characterisation of cell recruitment over the three phases of myogenesis, identifying muscle types as they arise. Specifically, we show that the myogenic cells arising during 2nd phase myogenesis are clearly different from the myogenic cells arising during the 3rd phase and that the dermomyotome is a major source of myogenic cells driving 2nd phase hyperplasia. These findings are discussed in relation to their implications for the generality of vertebrate developmental patterns.

Topical ketoconazole for infantile seborrhoeic dermatitis

In an open study, 19 infants with a bipolar seborrhoeic rash were treated with ketoconazole 2% in cream once a day and evaluated over 10 days of treatment. At day 10, 78.9% of patients were almost cleared. Percutaneous absorption peaked 1-3 h after topical treatment, and was minimal. No plasma ketoconazole accumulation over the 10-day treatment was detected. Treatment failures corresponded to histologically psoriasiform eruptions and probable atopic dermatitis.