474 research outputs found

    Indispensable role of Mdm2/p53 interaction during the embryonic and postnatal inner ear development

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    p53 is a key component of a signaling network that protects cells against various stresses. As excess p53 is detrimental to cells, its levels are tightly controlled by several mechanisms. The E3 ubiquitin ligase Mdm2 is a major negative regulator of p53. The significance of balanced p53 levels in normal tissues, at different stages of lifetime, is poorly understood. We have studied in vivo how the disruption of Mdm2/p53 interaction affects the early-embryonic otic progenitor cells and their descendants, the auditory supporting cells and hair cells. We found that p53 accumulation, as a consequence of Mdm2 abrogation, is lethal to both proliferative progenitors and non-proliferating, differentiating cells. The sensitivity of postmitotic supporting cells to excess p53 decreases along maturation, suggesting that maturation-related mechanisms limit p53's transcriptional activity towards pro-apoptotic factors. We have also investigated in vitro whether p53 restricts supporting cell's regenerative capacity. Unlike in several other regenerative cellular models, p53 inactivation did not alter supporting cell's proliferative quiescence nor transdifferentiation capacity. Altogether, the postmitotic status of developing hair cells and supporting cells does not confer protection against the detrimental effects of p53 upregulation. These findings might be linked to auditory disturbances observed in developmental syndromes with inappropriate p53 upregulation.Peer reviewe

    Macromolecular and electrical coupling between inner hair cells in the rodent cochlea

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    Inner hair cells (IHCs) are the primary receptors for hearing. They are housed in the cochlea and convey sound information to the brain via synapses with the auditory nerve. IHCs have been thought to be electrically and metabolically independent from each other. We report that, upon developmental maturation, in mice 30% of the IHCs are electrochemically coupled in ‘mini-syncytia’. This coupling permits transfer of fluorescently-labeled metabolites and macromolecular tracers. The membrane capacitance, Ca2+-current, and resting current increase with the number of dye-coupled IHCs. Dual voltage-clamp experiments substantiate low resistance electrical coupling. Pharmacology and tracer permeability rule out coupling by gap junctions and purinoceptors. 3D electron microscopy indicates instead that IHCs are coupled by membrane fusion sites. Consequently, depolarization of one IHC triggers presynaptic Ca2+-influx at active zones in the entire mini-syncytium. Based on our findings and modeling, we propose that IHC-mini-syncytia enhance sensitivity and reliability of cochlear sound encoding

    Electrocardiogram as a predictor of sudden cardiac death in middle-aged subjects without a known cardiac disease

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    Background: Abnormal 12 lead electrocardiogram (ECG) findings and proposing its ability for enhanced risk prediction, majority of the studies have been carried out with elderly populations with prior cardiovascular diseases. This study aims to denote the association of sudden cardiac death (SCD) and various abnormal ECG morphologies using middle-aged population without a known cardiac disease. Methods: In total, 9511 middle-aged subjects (mean age 42 +/- 8.2 years, 52% males) without a known cardiac disease were included in this study. Risk for SCD was assessed after 10 and 30-years of follow-up. Results: Abnormal ECG was present in 16.3% (N = 1548) of subjects. The incidence of SCD was distinctly higher among those with any ECG abnormality in 10 and 30-year follow-ups (1.7/1000 years vs. 0.6/1000 years, P 100', left ventricular hypertrophy, and T-wave inversions were the most significant independent ECG risk markers for 10-year SCD prediction with up to 3-fold risk for SCD. Those with ECG abnormalities had a 1.3-fold risk (95% CI 1.07-1.57, P - 0.007) for SCD in 30-year follow-up, whereas QRST-angle > 100 degrees, LVH, ER 0.1 mV and 0.2 mV were the strongest individual predictors. Subjects with multiple ECG abnormalities had up to 6.6-fold risk for SCD (P <0.001). Conclusion: Several ECG abnormalities are associated with the occurrence of early and late SCD events in the middle-age subjects without known history of cardiac disease. (C) 2018 The Authors. Published by Elsevier B.V.Peer reviewe

    Negotiating care in the context of Finnish and Italian elder care policies

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    Negotiation is an integral part of all elder care, which by definition involves a relation between at least two people. In this article we analyse negotiations concerning elder care in the context of Finnish and Italian elder care policies. At the macro level negotiations on elder care are shaped by elder care policies and at the micro level by individual skills and resources. Our focus is on the negotiations on eligibility that take place when elders attempt to access care. The data consist of qualitative interviews with Finnish and Italian elders in need of care. The analysis of individual experiences of care negotiations reflects the implementation of elder care policies. The results indicate that the most negotiated eligibility criteria when seeking access to elder care are need, money and social relations. These criteria are negotiated when seeking eligibility to different sources of care: informal care, grey market, market-based, non-profit and public services. In Italy, negotiation is particularly crucial when accessing grey market care. Cash as the main Italian elder care policy tool tends to enhance the role of and need for negotiation. In Finland, a greater part of elder care is provided by the public sector and therefore the process of negotiation is more standardized than in Italy

    Combined comparative genomic hybridization and transcriptomic analyses of ovarian granulosa cell tumors point to novel candidate driver genes

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    Background: Ovarian granulosa cell tumors (GCTs) are the most frequent sex cord-stromal tumors. Several studies have shown that a somatic mutation leading to a C134W substitution in the transcription factor FOXL2 appears in more than 95% of adult-type GCTs. Its pervasive presence suggests that FOXL2 is the main cancer driver gene. However, other mutations and genomic changes might also contribute to tumor formation and/or progression. Methods: We have performed a combined comparative genomic hybridization and transcriptomic analyses of 10 adult-type GCTs to obtain a picture of the genomic landscape of this cancer type and to identify new candidate co-driver genes. Results: Our results, along with a review of previous molecular studies, show the existence of highly recurrent chromosomal imbalances (especially, trisomy 14 and monosomy 22) and preferential co-occurrences (i.e. trisomy 14/monosomy 22 and trisomy 7/monosomy 16q). In-depth analyses showed the presence of recurrently broken, amplified/duplicated or deleted genes. Many of these genes, such as AKT1, RUNX1 and LIMA1, are known to be involved in cancer and related processes. Further genomic explorations suggest that they are functionally related. Conclusions: Our combined analysis identifies potential candidate genes, whose alterations might contribute to adult-type GCT formation/progression together with the recurrent FOXL2 somatic mutation.Peer reviewe

    The art of governing local education markets : Municipalities and school choice in Finland

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    Since the 1980s, numerous education reforms in Europe and beyond have sought to dismantle centralised bureaucracies and replace them with devolved systems of schooling that emphasise parental choice and competition between diversified types of schools. Despite this general trend, Finland continues to emphasise the municipal assignment of school places, albeit with the possibility of locally controlled choice. The aim of this paper is to elaborate on the ways in which Finnish local education authorities – involving both officials and politicians – define themselves in relation to the changing conceptions of the Nordic welfare state model. The paper discusses the social costs and benefits of school choice in addition to the kinds of techniques these authorities use when aiming to control and manage the social costs and benefits of school choice. Based on nine in-depth thematic interviews with local education authorities, the modalities – having to, being-able, wanting and knowing how – will be analysed.Peer reviewe
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