Correction to: Routine versus on demand removal of the syndesmotic screw; a protocol for an international randomised controlled trial (RODEO-trial).

An amendment to this paper has been published and can be accessed via the original article.

Routine versus on demand removal of the syndesmotic screw; a protocol for an international randomised controlled trial (RODEO-trial).

BACKGROUND: Syndesmotic injuries are common and their incidence is rising. In case of surgical fixation of the syndesmosis a metal syndesmotic screw is used most often. It is however unclear whether this screw needs to be removed routinely after the syndesmosis has healed. Traditionally the screw is removed after six to 12 weeks as it is thought to hamper ankle functional and to be a source of pain. Some studies however suggest this is only the case in a minority of patients. We therefore aim to investigate the effect of retaining the syndesmotic screw on functional outcome. DESIGN: This is a pragmatic international multicentre randomised controlled trial in patients with an acute syndesmotic injury for which a metallic syndesmotic screw was placed. Patients will be randomised to either routine removal of the syndesmotic screw or removal on demand. Primary outcome is functional recovery at 12 months measured with the Olerud-Molander Score. Secondary outcomes are quality of life, pain and costs. In total 194 patients will be needed to demonstrate non-inferiority between the two interventions at 80% power and a significance level of 0.025 including 15% loss to follow-up. DISCUSSION: If removal on demand of the syndesmotic screw is non-inferior to routine removal in terms of functional outcome, this will offer a strong argument to adopt this as standard practice of care. This means that patients will not have to undergo a secondary procedure, leading to less complications and subsequent lower costs. TRIAL REGISTRATION: This study was registered at the Netherlands Trial Register (NTR5965), Clinicaltrials.gov ( NCT02896998 ) on July 15th 2016.

SKOV3 cells containing a truncated ARID1a protein have a restricted genome-wide response to glucocorticoids.

AT-rich interacting domain subunit 1a (ARID1a) is an essential SWI/SNF component frequently mutated in human cancers. ARID1a mutations have also been associated with glucocorticoid resistance, potentially related to the well-established role of the SWI/SNF complex in glucocorticoid target gene regulation. Glucocorticoids are steroid hormones important for regulating many physiological processes through the activation of the glucocorticoid receptor (GR). As GR interacts directly with ARID1a, we hypothesized that a truncating ARID mutation would interfere with GR-dependent gene regulation. Using high throughput RNA sequencing (RNA-SEQ) we show a restricted glucocorticoid response in SKOV3 cells, which contain an inactivating ARID1a mutation. We also show a lack of GR binding at the GR-dependent regulatory site in the Period 1 gene, which has previously been shown to require chromatin remodelling. Taken together, our data suggests that ARID1a may be required for regulation of a subset of glucocorticoid responsive genes. In the case of SKOV3 cells, in which ARID1a is mutated, glucocorticoid-dependent transcriptional regulation of these genes is significantly impaired.

Circannual variation in thyroid hormone deiodinases in a short-day breeder.

At temperate latitudes, many mammals and birds show internally timed, long-term changes in seasonal physiology, synchronised to the seasons by changing day length (photoperiod). Photoperiodic control of thyroid hormone levels in the hypothalamus dictates the timing. This is effected through reciprocal regulation of thyroid hormone deiodinase gene expression. The local synthesis of type 2 deiodinase (Dio2) promotes triiodothyronine (T3) production and summer biology, whereas type 3 deiodinase (Dio3) promotes T3 degradation and winter biology. In the present study, we investigated the extent to which the hypothalamic expression of Dio2 and Dio3 is circannually regulated in the Soay sheep, a short-day breeding mammal. Male sheep were exposed to a long photoperiod (LP; 16 : 24 h light/dark cycle) or a short photoperiod (SP; 8 : 24 h light/dark cycle), for up to 28 weeks to establish four different endocrine states: (i) LP animals in a spring/summer-like state of reproductive arrest; (ii) LP refractory (LPR) animals showing spontaneous reproductive reactivation; (iii) SP animals showing autumn/winter-like reproductive activation; and (iv) SP refractory (SPR) animals showing spontaneous reproductive arrest. A complex pattern of hypothalamic Dio2 and Dio3 expression was observed, revealing distinctive photoperiod-driven and internally timed effects for both genes. The patterns of expression differed both spatially and temporally, with phases of peak Dio2 expression in the median eminence and tuberoinfundibular sulcus, as well as in the paraventricular zone (PVZ) (maximal under LP), whereas Dio3 expression was always confined to the PVZ (maximal under SP). These effects likely reflect the distinct roles of these enzymes in the localised control of hypothalamic T3 levels. The spontaneous decline in Dio2 and spontaneous increase in Dio3 in LPR animals occurred with a corresponding decline in thyroid-stimulating hormone ß expression in the neighbouring pars tuberalis (PT), although this relationship did not hold for the corresponding Dio2 increase/Dio3 decrease seen in SPR animals. We conclude that internally timed and spatially regulated changes in Dio2 and Dio3 expression may drive the cycling between breeding and nonbreeding states in long-lived seasonal species, and may be either PT-dependent or PT-independent at different phases of the circannual cycle.

Evidence for RGS4 modulation of melatonin and thyrotrophin signalling pathways in the pars tuberalis.

In mammals, the pineal hormone melatonin is secreted nocturnally and acts in the pars tuberalis (PT) of the anterior pituitary to control seasonal neuroendocrine function. Melatonin signals through the type 1 Gi-protein coupled melatonin receptor (MT1), inhibiting adenylate cyclase (AC) activity and thereby reducing intracellular concentrations of the second messenger, cAMP. Because melatonin action ceases by the end of the night, this allows a daily rise in cAMP levels, which plays a key part in the photoperiodic response mechanism in the PT. In addition, melatonin receptor desensitisation and sensitisation of AC by melatonin itself appear to fine-tune this process. Opposing the actions of melatonin, thyroid-stimulating hormone (TSH), produced by PT cells, signals through its cognate Gs-protein coupled receptor (TSH-R), leading to increased cAMP production. This effect may contribute to increased TSH production by the PT during spring and summer, and is of considerable interest because TSH plays a pivotal role in seasonal neuroendocrine function. Because cAMP stands at the crossroads between melatonin and TSH signalling pathways, any protein modulating cAMP production has the potential to impact on photoperiodic readout. In the present study, we show that the regulator of G-protein signalling RGS4 is a melatonin-responsive gene, whose expression in the PT increases some 2.5-fold after melatonin treatment. Correspondingly, RGS4 expression is acutely sensitive to changing day length. In sheep acclimated to short days (SP, 8 h light/day), RGS4 expression increases sharply following dark onset, peaking in the middle of the night before declining to basal levels by dawn. Extending the day length to 16 h (LP) by an acute 8-h delay in lights off causes a corresponding delay in the evening rise of RGS4 expression, and the return to basal levels is delayed some 4 h into the next morning. To test the hypothesis that RGS4 expression modulates interactions between melatonin- and TSH-dependent cAMP signalling pathways, we used transient transfections of MT1, TSH-R and RGS4 in COS7 cells along with a cAMP-response element luciferase reporter (CRE-luc). RGS4 attenuated MT1-mediated inhibition of TSH-stimulated CRE-luc activation. We propose that RGS4 contributes to photoperiodic sensitivity in the morning induction of cAMP-dependent gene expression in the PT.

RFamide-related peptide and its cognate receptor in the sheep: cDNA cloning, mRNA distribution in the hypothalamus and the effect of photoperiod.

Photoperiodic responses enable animals to adapt their physiology to predictable patterns of seasonal environmental change. In mammals, this depends on pineal melatonin secretion and effects in the hypothalamus, but the cellular and molecular substrates of its action are poorly understood. The recent identification of a mammalian orthologue of the avian gonadotrophin-inhibitory hormone gene has led to interest in its possible involvement in seasonal breeding. In long-day breeding Syrian hamsters, hypothalamic RFamide-related peptide (RFRP) expression is increased by exposure to long photoperiod. Because, opposite to hamsters, sheep are short-day breeders, we predicted that a conserved role in mammalian reproductive activation would decrease RFRP expression in sheep under a long photoperiod. We cloned the ovine RFRP cDNA and examined its expression pattern in Soay sheep acclimated to a 16 : 8 h or 8 : 16 h light /dark cycle (LP and SP, respectively). RFRP was expressed widely in the sheep hypothalamus and increased modestly overall with exposure to LP. Interestingly, RFRP expression in the ependymal cells surrounding the base of the third ventricle was highly photoperiodic, with levels being undetectable in animals held on SP but consistently high under LP. These data are inconsistent with a conserved reproductive role for RFRP across mammals. Additionally, we cloned the ovine homologue of the cognate RFRP receptor, rfr-2 (NPFF1) and found localised expression in the suprachiasmatic nuclei and in the pars tuberalis. Taken together, these data strengthen the emerging view that interplay between ependymal cells and the pars tuberalis might be important for the seasonal timing system.