Minimizing radiation injury and neoplastic effects during pediatric fluoroscopy: what should we know?

Radiation-induced injuries from fluoroscopic procedures in pediatric patients have occurred, and young patients are at greatest risk of many radiation-induced neoplasms. Some fluoroscopists have been injured from their use of fluoroscopy, and they are known to be at risk of radiation-induced neoplasm when radiation is not well-controlled. This article reviews the circumstances that lead to radiation injury and delineates some procedural methods to avoid injury and limit radiation exposure to both the patient and the fluoroscopist

Transcorneal electrical stimulation for the treatment of retinitis pigmentosa: results from the TESOLAUK trial

OBJECTIVE: To explore the impact of weekly transcorneal electrical stimulation (TES) over a 6-month period as a treatment for retinitis pigmentosa (RP). METHODS AND ANALYSIS: A prospective open-label observational trial was carried out assessing weekly TES in participants with RP for a period of 6 months followed by observation for a further 6 months. Clinical examination and investigations were carried out at 3 monthly intervals for a total of 12 months. The primary outcome measure explored safety through a descriptive analysis of adverse effects with secondary outcome measures evaluating structural and functional efficacy. RESULTS: Seven male and seven female participants with RP aged 18-80 years were recruited. TES was well tolerated with no serious adverse events reported. Two participants reported transient foreign body sensation and one participant had discomfort underneath the skin electrode. Following 6 months of TES, best-corrected visual acuity increased by 1.1±1.4 letters in the control arm and 0.93±1.4 letters in the treated arm. Central microperimetry threshold sensitivity rose by 0.02±0.5 decibels (dB) and 0.37±0.4 dB and Goldmann visual field volume by 0.16±0.09 steradians (sr) vs 0.22±0.12 sr for the control and treated eye, respectively. There was no statistical significance seen between eyes following the treatment or observation period. CONCLUSION:: This small open-label clinical trial showed that TES was safe and well tolerated in patients with RP. Visual function measurements at 6 months demonstrated no significant difference between the control and treated eyes. The results justify a larger clinical trial over a longer period of time in order to identify any treatment effect

Clientelism and economic policy: Greece and the crisis

Clientelism and Economic Policy is an application of public choice to explain the contemporary political economy of Greece, as well as a broader theoretical contribution to the study of clientelism as a political and economic phenomenon

Degeneracy: a link between evolvability, robustness and complexity in biological systems

A full accounting of biological robustness remains elusive; both in terms of the mechanisms by which robustness is achieved and the forces that have caused robustness to grow over evolutionary time. Although its importance to topics such as ecosystem services and resilience is well recognized, the broader relationship between robustness and evolution is only starting to be fully appreciated. A renewed interest in this relationship has been prompted by evidence that mutational robustness can play a positive role in the discovery of adaptive innovations (evolvability) and evidence of an intimate relationship between robustness and complexity in biology. This paper offers a new perspective on the mechanics of evolution and the origins of complexity, robustness, and evolvability. Here we explore the hypothesis that degeneracy, a partial overlap in the functioning of multi-functional components, plays a central role in the evolution and robustness of complex forms. In support of this hypothesis, we present evidence that degeneracy is a fundamental source of robustness, it is intimately tied to multi-scaled complexity, and it establishes conditions that are necessary for system evolvability

Evolutionary connectionism: algorithmic principles underlying the evolution of biological organisation in evo-devo, evo-eco and evolutionary transitions

The mechanisms of variation, selection and inheritance, on which evolution by natural selection depends, are not fixed over evolutionary time. Current evolutionary biology is increasingly focussed on understanding how the evolution of developmental organisations modifies the distribution of phenotypic variation, the evolution of ecological relationships modifies the selective environment, and the evolution of reproductive relationships modifies the heritability of the evolutionary unit. The major transitions in evolution, in particular, involve radical changes in developmental, ecological and reproductive organisations that instantiate variation, selection and inheritance at a higher level of biological organisation. However, current evolutionary theory is poorly equipped to describe how these organisations change over evolutionary time and especially how that results in adaptive complexes at successive scales of organisation (the key problem is that evolution is self-referential, i.e. the products of evolution change the parameters of the evolutionary process). Here we first reinterpret the central open questions in these domains from a perspective that emphasises the common underlying themes. We then synthesise the findings from a developing body of work that is building a new theoretical approach to these questions by converting well-understood theory and results from models of cognitive learning. Specifically, connectionist models of memory and learning demonstrate how simple incremental mechanisms, adjusting the relationships between individually-simple components, can produce organisations that exhibit complex system-level behaviours and improve the adaptive capabilities of the system. We use the term “evolutionary connectionism” to recognise that, by functionally equivalent processes, natural selection acting on the relationships within and between evolutionary entities can result in organisations that produce complex system-level behaviours in evolutionary systems and modify the adaptive capabilities of natural selection over time. We review the evidence supporting the functional equivalences between the domains of learning and of evolution, and discuss the potential for this to resolve conceptual problems in our understanding of the evolution of developmental, ecological and reproductive organisations and, in particular, the major evolutionary transitions

Genome-Wide Survey of MicroRNA - Transcription Factor Feed-Forward Regulatory Circuits in Human

In this work, we describe a computational framework for the genome-wide identification and characterization of mixed transcriptional/post-transcriptional regulatory circuits in humans. We concentrated in particular on feed-forward loops (FFL), in which a master transcription factor regulates a microRNA, and together with it, a set of joint target protein coding genes. The circuits were assembled with a two step procedure. We first constructed separately the transcriptional and post-transcriptional components of the human regulatory network by looking for conserved over-represented motifs in human and mouse promoters, and 3'-UTRs. Then, we combined the two subnetworks looking for mixed feed-forward regulatory interactions, finding a total of 638 putative (merged) FFLs. In order to investigate their biological relevance, we filtered these circuits using three selection criteria: (I) GeneOntology enrichment among the joint targets of the FFL, (II) independent computational evidence for the regulatory interactions of the FFL, extracted from external databases, and (III) relevance of the FFL in cancer. Most of the selected FFLs seem to be involved in various aspects of organism development and differentiation. We finally discuss a few of the most interesting cases in detail.Comment: 51 pages, 5 figures, 4 tables. Supporting information included. Accepted for publication in Molecular BioSystem

Hum. Reprod. Advance

what is known already: A global decrease in human sperm quality is still debated as geographical differences have been shown, and many criticisms have risen concerning studies with small and biased study populations or inappropriate statistical methodology. However, growing biological, toxicological, experimental and human exposure data support the endocrine disruptors' hypothesis assuming that fetal exposure to endocrine disruptors could impair reproductive outcomes. study design, size, duration: This was a retrospective and descriptive study using data registered by Fivnat, the professional association in charge of statistics for ART in France during the 1989-2005 study period. Data were provided by 126 main ART centres over the whole metropolitan territory. The source population included 154 712 men, aged 18-70, who were partners of couples undergoing their first ART cycle and for whom semen quality indicators (concentration, total motility and percentage of morphologically normal forms), measured on fresh ejaculated semen, were available. participants/materials, setting, methods: The study population was 26 609 partners of women who had both tubes either absent or blocked. The temporal trends for each indicator of semen quality were modelled using a generalized additive model that allowed for nonlinear relationships between variables and were adjusted for season and age. In-depth sensitivity analyses included the reiteration of the analysis on data from a second spermiogram available for each man and on another subsample of men diagnosed as fertile. Variables such as centre, technique (standard in vitro fertilization or intra-cytoplasmic sperm injection) and an interaction factor between technique and time were also included in the model. main results and the role of chance: There was a significant and continuous decrease in sperm concentration of 32.2% [26.3-36.3] during the study period. Projections indicate that concentration for a 35-year-old man went from an average of 73.6 million/ml [69.0-78.4] in 1989 to 49.9 million/ml [43.5-54.7] in 2005. A significant, but not quantifiable, decrease in the percentage of sperm with morphologically normal forms along the 17-year period was also observed. There was no global trend but a slight, significant increase in total motility between 1994 and 1998 was observed. The results were robust after sensitivity analysis. limitations, reasons for caution: Socioeconomic status could not be controlled for. Despite universal access to medical services in France, couples undergoing ART are expected to have a higher educational level on average compared with those of the general population. Therefore, the real values in the general population could be slightly lower than those presented and the decrease possibly stronger, as the population study is less likely to smoke or be overweight, two factors known to impair semen quality. wider implications of the findings: As the men were selected without a priori knowledge regarding their semen quality characteristics, the results are expected to be close to the values in the general French population. The very large sample size and the robustness of the results confer great statistical power and credibility to the results. To our knowledge, it is the first study concluding a severe and general decrease in sperm concentration and morphology at the scale of a whole country over a substantial period. This constitutes a serious public health warning. The link with the environment particularly needs to be determined