RAPIDASH: A tag-free enrichment of ribosome-associated proteins reveals compositional dynamics in embryonic tissues and stimulated macrophages

Ribosomes are emerging as direct regulators of gene expression, with ribosome-associated proteins (RAPs) allowing ribosomes to modulate translational control. However, a lack of technologies to enrich RAPs across many sample types has prevented systematic analysis of RAP number, dynamics, and functions. Here, we have developed a label-free methodology called RAPIDASH to enrich ribosomes and RAPs from any sample. We applied RAPIDASH to mouse embryonic tissues and identified hundreds of potential RAPs, including DHX30 and LLPH, two forebrain RAPs important for neurodevelopment. We identified a critical role of LLPH in neural development that is linked to the translation of genes with long coding sequences. Finally, we characterized ribosome composition remodeling during immune activation and observed extensive changes post-stimulation. RAPIDASH has therefore enabled the discovery of RAPs ranging from those with neuroregulatory functions to those activated by immune stimuli, thereby providing critical insights into how ribosomes are remodeled.

Diversity of ribosomes at the level of rRNA variation associated with human health and disease

With hundreds of copies of ribosomal DNA (rDNA) it is unknown whether they possess sequence variations that ultimately form different types of ribosomes. Here, we developed an algorithm for variant-calling between paralog genes (termed RGA) and compared rDNA variations with rRNA variations from long-read sequencing of translating ribosomes (RIBO-RT). Our analyses identified dozens of highly abundant rRNA variants, largely indels, that are incorporated into translationally active ribosomes and assemble into distinct ribosome subtypes encoded on different chromosomes. We developed an in-situ rRNA sequencing method (SWITCH-seq) revealing that variants are co-expressed within individual cells and found that they possess different structures. Lastly, we observed tissue-specific rRNA-subtype expression and linked specific rRNA variants to cancer. This study therefore reveals the variation landscape of translating ribosomes within human cells.

Evolutionarily divergent mTOR remodels translatome for tissue regeneration

An outstanding mystery in biology is why some species, such as the axolotl, can regenerate tissues whereas mammals cannot1. Here, we demonstrate that rapid activation of protein synthesis is a unique feature of the injury response critical for limb regeneration in the axolotl (Ambystoma mexicanum). By applying polysome sequencing, we identify hundreds of transcripts, including antioxidants and ribosome components that are selectively activated at the level of translation from pre-existing messenger RNAs in response to injury. By contrast, protein synthesis is not activated in response to non-regenerative digit amputation in the mouse. We identify the mTORC1 pathway as a key upstream signal that mediates tissue regeneration and translational control in the axolotl. We discover unique expansions in mTOR protein sequence among urodele amphibians. By engineering an axolotl mTOR (axmTOR) in human cells, we show that these changes create a hypersensitive kinase that allows axolotls to maintain this pathway in a highly labile state primed for rapid activation. This change renders axolotl mTOR more sensitive to nutrient sensing, and inhibition of amino acid transport is sufficient to inhibit tissue regeneration. Together, these findings highlight the unanticipated impact of the translatome on orchestrating the early steps of wound healing in a highly regenerative species and provide a missing link in our understanding of vertebrate regenerative potential.

Subfunctionalized expression drives evolutionary retention of ribosomal protein paralogs Rps27 and Rps27l in vertebrates

The formation of paralogs through gene duplication is a core evolutionary process. For paralogs that encode components of protein complexes such as the ribosome, a central question is whether they encode functionally distinct proteins or whether they exist to maintain appropriate total expression of equivalent proteins. Here, we systematically tested evolutionary models of paralog function using the ribosomal protein paralogs Rps27 (eS27) and Rps27l (eS27L) as a case study. Evolutionary analysis suggests that Rps27 and Rps27l likely arose during whole-genome duplication(s) in a common vertebrate ancestor. We show that Rps27 and Rps27l have inversely correlated mRNA abundance across mouse cell types, with the highest Rps27 in lymphocytes and the highest Rps27l in mammary alveolar cells and hepatocytes. By endogenously tagging the Rps27 and Rps27l proteins, we demonstrate that Rps27- and Rps27l-ribosomes associate preferentially with different transcripts. Furthermore, murine Rps27 and Rps27l loss-of-function alleles are homozygous lethal at different developmental stages. However, strikingly, expressing Rps27 protein from the endogenous Rps27l locus or vice versa completely rescues loss-of-function lethality and yields mice with no detectable deficits. Together, these findings suggest that Rps27 and Rps27l are evolutionarily retained because their subfunctionalized expression patterns render both genes necessary to achieve the requisite total expression of two equivalent proteins across cell types. Our work represents the most in-depth characterization of a mammalian ribosomal protein paralog to date and highlights the importance of considering both protein function and expression when investigating paralogs.

[Thoracolumbar Compression Fractures in Children]

PURPOSE OF THE STUDY The study aimed to draw up a diagnosis and treatment guidelines for the management of the most common compression fractures of the thoracolumbar spine in children. MATERIAL AND METHODS Between 2015 and 2017, pediatric patients with a thoracolumbar injury aged 0-12 years were followed up in the University Hospital in Motol and the Thomayer University Hospital. The age and gender of the patient, injury etiology, fracture morphology, number of injured vertebrae, functional outcome (VAS and ODI modified for children), and complications were assessed. An X-ray was performed in all patients, in indicated cases also an MRI scan was done, and in more severe cases a CT scan was obtained as well. RESULTS The average vertebral body kyphosis in patients with one injured vertebra was 7.3° (range 1.1°-12.5°). The average vertebral body kyphosis in patients with two injured vertebrae was 5.5° (range 2.1°-12.2°). The average vertebral body kyphosis in patients with more than two injured vertebrae was 3.8° (range 0.2°-11.5°). All patients were treated conservatively in line with the proposed protocol. No complications were observed, no deterioration of the kyphotic shape of the vertebral body was reported, no instability occurred, and no surgical intervention had to be considered. DISCUSSION Pediatric spine injuries are in most cases treated conservatively. Surgical treatment is opted for in 7.5-18% of cases, in dependence on the evaluated group of patients, age of the patients and philosophy of the department concerned. In our group, all patients were treated conservatively. CONCLUSIONS 1. To diagnose F0 fractures, two unenhanced orthogonal view X-rays are indicated, whereas MRI examination is not routinely performed. In F1 fractures, an X-ray is indicated, and an MRI scan is considered based on the age and extent of injury. In F2 and F3 fractures, an X-ray is indicated and subsequently the diagnosis is confirmed by MRI, in F3 fractures also a CT scan is performed. 2. In young children (under 6 years of age), in whom an MRI procedure would require general anaesthesia, MRI is not routinely performed. 3. In F0 fractures, crutches or a brace are not indicated. In F1 fractures, verticalization using crutches or a brace is considered in dependence on the patient's age and extent of injury. In F2 fractures, verticalization using crutches or a brace is indicated. 4. In F3 fractures, surgical treatment is considered, followed by verticalization using crutches or a brace. In case of conservative treatment, the same procedures as in F2 fractures are applied. 5. Long-term bed rest is contraindicated. 6. Duration of spinal load reduction (restriction of sports activities, or verticalization using crutches or a brace) in F1 injuries is 3-6 weeks based on the age of the patient, it increases with the age, with the minimum being 3 weeks. 7. Duration of spinal load reduction (verticalization using crutches or a brace) in F2 and F3 injuries is 6-12 weeks based on the age of the patient, it increases with the age, with the minimum being 6 weeks. Key words: pediatric spine injury, thoracolumbar compression fractures, children trauma treatment.

Regulation of eIF4E guides a unique translational program to control erythroid maturation

Translation control is essential in balancing hematopoietic precursors and differentiation; however, the mechanisms underlying this program are poorly understood. We found that the activity of the major cap-binding protein eIF4E is unexpectedly regulated in a dynamic manner throughout erythropoiesis that is uncoupled from global protein synthesis rates. Moreover, eIF4E activity directs erythroid maturation, and increased eIF4E expression maintains cells in an early erythroid state associated with a translation program driving the expression of PTPN6 and Igf2bp1. A cytosine-enriched motif in the 5' untranslated region is important for eIF4E-mediated translation specificity. Therefore, selective translation of key target genes necessary for the maintenance of early erythroid states by eIF4E highlights a unique mechanism used by hematopoietic precursors to rapidly elicit erythropoietic maturation upon need.

Animal models of Diamond-Blackfan anemia: updates and challenges

Diamond-Blackfan anemia (DBA) is a ribosomopathy that is characterized by macrocytic anemia, congenital malformations, and early onset during childhood. Genetic studies have demonstrated that most patients carry mutations in one of the 20 related genes, most of which encode ribosomal proteins (RP). Treatment of DBA includes corticosteroid therapy, chronic red blood cell transfusion, and other forms of immunosuppression. Currently, hematopoietic stem cell transplantation is the only cure for DBA. Interestingly, spontaneous remissions occur in 10-20% of transfusion-dependent DBA patients. However, there is no consistent association between specific mutations and clinical manifestations. In the past decades, researchers have made significant progress in understanding the pathogenesis of DBA, but it remains unclear how the ubiquitous RP haploinsufficiency causes the erythroid-specific defect in hematopoiesis in DBA patients, and why there is a difference in penetrance and spontaneous remission among individuals who carry identical mutations. In this paper, we provide a comprehensive review of the development of DBA animal models and discuss the future research directions for these important experimental systems.

A stem cell roadmap of ribosome heterogeneity reveals a function for RPL10A in mesoderm production

Recent findings suggest that the ribosome itself modulates gene expression. However, whether ribosomes change composition across cell types or control cell fate remains unknown. Here, employing quantitative mass spectrometry during human embryonic stem cell differentiation, we identify dozens of ribosome composition changes underlying cell fate specification. We observe upregulation of RPL10A/uL1-containing ribosomes in the primitive streak followed by progressive decreases during mesoderm differentiation. An Rpl10a loss-of-function allele in mice causes striking early mesodermal phenotypes, including posterior trunk truncations, and inhibits paraxial mesoderm production in culture. Ribosome profiling in Rpl10a loss-of-function mice reveals decreased translation of mesoderm regulators, including Wnt pathway mRNAs, which are also enriched on RPL10A/uL1-containing ribosomes. We further show that RPL10A/uL1 regulates canonical and non-canonical Wnt signaling during stem cell differentiation and in the developing embryo. These findings reveal unexpected ribosome composition modularity that controls differentiation and development through the specialized translation of key signaling networks.

Combinatorial optimization of mRNA structure, stability, and translation for RNA-based therapeutics

Therapeutic mRNAs and vaccines are being developed for a broad range of human diseases, including COVID-19. However, their optimization is hindered by mRNA instability and inefficient protein expression. Here, we describe design principles that overcome these barriers. We develop an RNA sequencing-based platform called PERSIST-seq to systematically delineate in-cell mRNA stability, ribosome load, as well as in-solution stability of a library of diverse mRNAs. We find that, surprisingly, in-cell stability is a greater driver of protein output than high ribosome load. We further introduce a method called In-line-seq, applied to thousands of diverse RNAs, that reveals sequence and structure-based rules for mitigating hydrolytic degradation. Our findings show that highly structured “superfolder” mRNAs can be designed to improve both stability and expression with further enhancement through pseudouridine nucleoside modification. Together, our study demonstrates simultaneous improvement of mRNA stability and protein expression and provides a computational-experimental platform for the enhancement of mRNA medicines.

The authors develop an RNA sequencing-based platform, PERSIST-seq, to simultaneously delineate in-cell mRNA stability, ribosome load, and in-solution stability of a diverse mRNA library to derive design principles for improved mRNA therapeutics.

[Complications in Spine Surgery: Prospective 13-year follow-up of unplanned revision spinal surgeries]

PURPOSE OF THE STUDY Unplanned revision spinal surgeries constitute a complication in the treatment algorithm for the patient, surgeon and the entire treatment team. Any complication leading to an unplanned revision surgery is therefore undesirable. The percentage of complications referred to in publications on this topic focusing on unplanned revision surgeries only varies from 0.7% to 29.8%, with obvious diversity of causes and significant risk factors. The purpose of the submitted paper is to carry out a prospective evaluation of the most serious complications requiring unplanned revision spinal surgeries in the course of 13 years at a single department performing a broad range of spinal surgeries, namely 1300 procedures annually on average. MATERIAL AND METHODS In the period 2006 - 2018, a total of 16872 patients underwent a surgery at our department. During this period, in 556 patients an unplanned revision spinal surgery was performed. In agreement with literature, the patients were categorised by cause for revision: 1/ impaired wound suprafascial (superficial) healing - superficial infection, 2/ impaired wound subfascial (deep) healing - deep infection, 3/ surgical wound hematoma, 4/ deterioration or occurrence of new neurological symptoms, 5/ cerebrospinal fluid leak (liquorrhoea) and 6/ others. The patients operated on for inflammatory diseases of the spine with subsequent infectious complications, primarily treated at another department, and the patients with open spinal injury were excluded from the study. According to these criteria, a cohort of 521 patients was followed up, namely 236 (45.3%) women and 285 (54.7%) men, aged 1 year to 86 years, with the mean age of 55.0 years (median 60 years). Demographic effects, tobacco smoking and comorbidities were followed up in the cohort, together with the effects of surgery, diagnosis, surgical approach and physician. All parameters were statistically evaluated at a p-value below 0.05, including comparison with the control group. RESULTS Of the total number of 16872 operated patients, a group of 521 (3.09%) patients undergoing a revision surgery for complications was analysed in detail. Impaired wound healing - infection (SSI) was found in 199 (1.18%) patients, of whom superficial infection in 124 cases (0.73%) and deep infection in 75 cases (0.44%). Hematoma in a surgical site was detected in 149 (0.88%) patients. In 63 (0.37%) cases, deterioration of the existing neurological finding or occurrence of a new neurological finding were observed, in 68 (0.40%) cases cerebrospinal fluid leak was reported and in 40 (0.24%) cases other complications were identified. As concerns the surgical assistant, the percentage of complications in a board-certified physician is 2.77 (1.14 - 3.29%), in a medical resident it increases to 3.60 (0.00 - 9.38%) (p<0.05). The prevalence of smokers in the group with complications (N=521) was 34.7%. The control group (N=3650) included 30.1% of smokers (p<0.05). The mean age of patients in the group with complications (N=521) was higher, i.e. 55.0 years, with the median age of 60.0 years, than in the primary cohort (N=16872) with the mean age of 49.8 years and the median age of 52.0 years (p<0.05). The mean BMI in the group with complications was (N=521) 27.3, the median BMI was 26.9. In the control group (N=16872), the mean BMI was 27.11, the median BMI was 26.8. In this case the significance (p>0.05) was not confirmed. The complications prevailed strongly in posterior surgical approach, namely in 483 patients (92.7%). As concerns the surgically treated segment, lumber spine dominates with 320 (61.4%) cases. Corticosteroid therapy was used twice as often in women, namely in 13.1% vs. 6.3%. The group of patients with complications (N=521) showed a much higher average length of hospital stay of 12.8 days compared to the average of 4.6 days (N=16872). DISCUSSION In our cohort, the complication rate was 3.09%, of which infections constituted 1.18%, which is in agreement with similarly focused papers. As regards the patient-related factors, in our study the results reported by literature were confirmed with respect to the age, smoking and comorbidities. Moreover, the posterior surgical procedure, lumber spine surgery and presence of a medical resident are essential (p<0.05). No major age difference was observed between women and men (p>0.05). Obesity is one of the key risk factors, especially in infectious complications. In our cohort, a higher BMI did not increase the risk of complications in general (p>0.05). CONCLUSIONS In correlation with current literature, our cohort confirmed a significantly higher risk of complications leading to revision spinal surgery associated with age, smoking, posterior surgical procedure in thoracic or lumber spine, and presence of a medical resident as a surgical assistant. The average length of hospital stay was demonstrably longer in complicated patients, it almost tripled compared to the whole cohort. Contrary to literature, the effect of obesity on the occurrence of complications was not confirmed. Key words: spinal surgery, complications, infection, reoperation, risk factor, hematoma, cerebrospinal fluid leak, screw malposition, smoking, obesity.

Controlling tissue patterning by translational regulation of signaling transcripts through the core translation factor eIF3c

Although gene expression is tightly regulated during embryonic development, the impact of translational control has received less experimental attention. Here, we find that eukaryotic translation initiation factor-3 (eIF3) is required for Shh-mediated tissue patterning. Analysis of loss-of-function eIF3 subunit c (Eif3c) mice reveal a unique sensitivity to the Shh receptor patched 1 (Ptch1) dosage. Genome-wide in vivo enhanced cross-linking immunoprecipitation sequence (eCLIP-seq) shows unexpected specificity for eIF3 binding to a pyrimidine-rich motif present in subsets of 5'-UTRs and a corresponding change in the translation of these transcripts by ribosome profiling in Eif3c loss-of-function embryos. We further find a transcript specific effect in Eif3c loss-of-function embryos whereby translation of Ptch1 through this pyrimidine-rich motif is specifically sensitive to eIF3 amount. Altogether, this work uncovers hidden specificity of housekeeping translation initiation machinery for the translation of key developmental signaling transcripts.

A p53-dependent translational program directs tissue-selective phenotypes in a model of ribosomopathies

In ribosomopathies, perturbed expression of ribosome components leads to tissue-specific phenotypes. What accounts for such tissue-selective manifestations as a result of mutations in the ribosome, a ubiquitous cellular machine, has remained a mystery. Combining mouse genetics and in vivo ribosome profiling, we observe limb-patterning phenotypes in ribosomal protein (RP) haploinsufficient embryos, and we uncover selective translational changes of transcripts that controlling limb development. Surprisingly, both loss of p53, which is activated by RP haploinsufficiency, and augmented protein synthesis rescue these phenotypes. These findings are explained by the finding that p53 functions as a master regulator of protein synthesis, at least in part, through transcriptional activation of 4E-BP1. 4E-BP1, a key translational regulator, in turn, facilitates selective changes in the translatome downstream of p53, and this thereby explains how RP haploinsufficiency may elicit specificity to gene expression. These results provide an integrative model to help understand how in vivo tissue-specific phenotypes emerge in ribosomopathies.

Combinatorial optimization of mRNA structure, stability, and translation for RNA-based therapeutics

Therapeutic mRNAs and vaccines are being developed for a broad range of human diseases, including COVID-19. However, their optimization is hindered by mRNA instability and inefficient protein expression. Here, we describe design principles that overcome these barriers. We develop a new RNA sequencing-based platform called PERSIST-seq to systematically delineate in-cell mRNA stability, ribosome load, as well as in-solution stability of a library of diverse mRNAs. We find that, surprisingly, in-cell stability is a greater driver of protein output than high ribosome load. We further introduce a method called In-line-seq, applied to thousands of diverse RNAs, that reveals sequence and structure-based rules for mitigating hydrolytic degradation. Our findings show that "superfolder" mRNAs can be designed to improve both stability and expression that are further enhanced through pseudouridine nucleoside modification. Together, our study demonstrates simultaneous improvement of mRNA stability and protein expression and provides a computational-experimental platform for the enhancement of mRNA medicines.

Optogenetic manipulation of cellular communication using engineered myosin motors

Cells achieve highly efficient and accurate communication through cellular projections such as neurites and filopodia, yet there is a lack of genetically encoded tools that can selectively manipulate their composition and dynamics. Here, we present a versatile optogenetic toolbox of artificial multi-headed myosin motors that can move bidirectionally within long cellular extensions and allow for the selective transport of GFP-tagged cargo with light. Utilizing these engineered motors, we could transport bulky transmembrane receptors and organelles as well as actin remodellers to control the dynamics of both filopodia and neurites. Using an optimized in vivo imaging scheme, we further demonstrate that, upon limb amputation in axolotls, a complex array of filopodial extensions is formed. We selectively modulated these filopodial extensions and showed that they re-establish a Sonic Hedgehog signalling gradient during regeneration. Considering the ubiquitous existence of actin-based extensions, this toolbox shows the potential to manipulate cellular communication with unprecedented accuracy.

VELCRO-IP RNA-seq reveals ribosome expansion segment function in translation genome-wide

Roles for ribosomal RNA (rRNA) in gene regulation remain largely unexplored. With hundreds of rDNA units positioned across multiple loci, it is not possible to genetically modify rRNA in mammalian cells, hindering understanding of ribosome function. It remains elusive whether expansion segments (ESs), tentacle-like rRNA extensions that vary in sequence and size across eukaryotic evolution, may have functional roles in translation control. Here, we develop variable expansion segment-ligand chimeric ribosome immunoprecipitation RNA sequencing (VELCRO-IP RNA-seq), a versatile methodology to generate species-adapted ESs and to map specific mRNA regions across the transcriptome that preferentially associate with ESs. Application of VELCRO-IP RNA-seq to a mammalian ES, ES9S, identified a large array of transcripts that are selectively recruited to ribosomes via an ES. We further characterize a set of 5′ UTRs that facilitate cap-independent translation through ES9S-mediated ribosome binding. Thus, we present a technology for studying the enigmatic ESs of the ribosome, revealing their function in gene-specific translation.

Leppek et al. develop a pulldown technology employing chimeric yeast ribosomes, VELCRO-IP RNA-seq, to map interactions between ribosomal RNA (rRNA) and mRNAs genome-wide with positional precision. They find that expansion segments (ESs), the extended rRNA tentacles of the ribosome, specifically bind 5′ UTR elements to enable cap-independent translation of select mRNAs.

Gene- and Species-Specific Hox mRNA Translation by Ribosome Expansion Segments

Ribosomes have been suggested to directly control gene regulation, but regulatory roles for ribosomal RNA (rRNA) remain largely unexplored. Expansion segments (ESs) consist of multitudes of tentacle-like rRNA structures extending from the core ribosome in eukaryotes. ESs are remarkably variable in sequence and size across eukaryotic evolution with largely unknown functions. In characterizing ribosome binding to a regulatory element within a Homeobox (Hox) 5' UTR, we identify a modular stem-loop within this element that binds to a single ES, ES9S. Engineering chimeric, "humanized" yeast ribosomes for ES9S reveals that an evolutionary change in the sequence of ES9S endows species-specific binding of Hoxa9 mRNA to the ribosome. Genome editing to site-specifically disrupt the Hoxa9-ES9S interaction demonstrates the functional importance for such selective mRNA-rRNA binding in translation control. Together, these studies unravel unexpected gene regulation directly mediated by rRNA and how ribosome evolution drives translation of critical developmental regulators.

RPS25 is required for efficient RAN translation of C9orf72 and other neurodegenerative disease-associated nucleotide repeats

Nucleotide repeat expansions in the C9orf72 gene are the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia. Unconventional translation (RAN translation) of C9orf72 repeats generates dipeptide repeat proteins that can cause neurodegeneration. We performed a genetic screen for regulators of RAN translation and identified small ribosomal protein subunit 25 (RPS25), presenting a potential therapeutic target for C9orf72-related amyotrophic lateral sclerosis and frontotemporal dementia and other neurodegenerative diseases caused by nucleotide repeat expansions.

Heterogeneity and specialized functions of translation machinery: from genes to organisms

Regulation of mRNA translation offers the opportunity to diversify the expression and abundance of proteins made from individual gene products in cells, tissues and organisms. Emerging evidence has highlighted variation in the composition and activity of several large, highly conserved translation complexes as a means to differentially control gene expression. Heterogeneity and specialized functions of individual components of the ribosome and of the translation initiation factor complexes eIF3 and eIF4F, which are required for recruitment of the ribosome to the mRNA 5' untranslated region, have been identified. In this Review, we summarize the evidence for selective mRNA translation by components of these macromolecular complexes as a means to dynamically control the translation of the proteome in time and space. We further discuss the implications of this form of gene expression regulation for a growing number of human genetic disorders associated with mutations in the translation machinery.

Decoding the Function of Expansion Segments in Ribosomes

Expansion segments (ESs) are enigmatic insertions within the eukaryotic ribosome, the longest of which resemble tentacle-like extensions that vary in length and sequence across evolution, with a largely unknown function. By selectively engineering rRNA in yeast, we find that one of the largest ESs, ES27L, has an unexpected function in translation fidelity. Ribosomes harboring a deletion in the distal portion of ES27L have increased amino acid misincorporation, as well as readthrough and frameshifting errors. By employing quantitative mass spectrometry, we further find that ES27L acts as an RNA scaffold to facilitate binding of a conserved enzyme, methionine amino peptidase (MetAP). We show that MetAP unexpectedly controls the accuracy of ribosome decoding, which is coupled to an increase in its enzymatic function through its interaction with ES27L. These findings reveal that variable ESs of the ribosome serve important functional roles and act as platforms for the binding of proteins that modulate translation across evolution.

Author Correction: Functional 5' UTR mRNA structures in eukaryotic translation regulation and how to find them

The legend of Figure 1 has been modified to remove misleading referencing to evolution. The title of the legend has been modified from 'Evolutionary expansion of eukaryotic 5' UTR lengths' to 'Interspecies variation in 5' UTR lengths'; the first sentence of the legend has been modified from 'The length of 5' untranslated regions (UTRs) has increased in eukaryotes during evolution…' to 'The length of 5' untranslated regions (UTRs) varies in eukaryotes…'. The changes have been made in the HTML and PDF versions of the manuscript.

The Discovery of Ribosome Heterogeneity and Its Implications for Gene Regulation and Organismal Life

The ribosome has recently transitioned from being viewed as a passive, indiscriminate machine to a more dynamic macromolecular complex with specialized roles in the cell. Here, we discuss the historical milestones from the discovery of the ribosome itself to how this ancient machinery has gained newfound appreciation as a more regulatory participant in the central dogma of gene expression. The first emerging examples of direct changes in ribosome composition at the RNA and protein level, coupled with an increased awareness of the role individual ribosomal components play in the translation of specific mRNAs, is opening a new field of study centered on ribosome-mediated control of gene regulation. In this Perspective, we discuss our current understanding of the known functions for ribosome heterogeneity, including specialized translation of individual transcripts, and its implications for the regulation and expression of key gene regulatory networks. In addition, we suggest what the crucial next steps are to ascertain the extent of ribosome heterogeneity and specialization and its importance for regulation of the proteome within subcellular space, across different cell types, and during multi-cellular organismal development.

The Discovery of Ribosome Heterogeneity and Its Implications for Gene Regulation and Organismal Life

The ribosome has recently transitioned from being viewed as a passive, indiscriminate machine to a more dynamic macromolecular complex with specialized roles in the cell. Here, we discuss the historical milestones from the discovery of the ribosome itself to how this ancient machinery has gained newfound appreciation as a more regulatory participant in the central dogma of gene expression. The first emerging examples of direct changes in ribosome composition at the RNA and protein level, coupled with an increased awareness of the role individual ribosomal components play in the translation of specific mRNAs, is opening a new field of study centered on ribosome-mediated control of gene regulation. In this Perspective, we discuss our current understanding of the known functions for ribosome heterogeneity, including specialized translation of individual transcripts, and its implications for the regulation and expression of key gene regulatory networks. In addition, we suggest what the crucial next steps are to ascertain the extent of ribosome heterogeneity and specialization and its importance for regulation of the proteome within subcellular space, across different cell types, and during multi-cellular organismal development.

Functional 5' UTR mRNA structures in eukaryotic translation regulation and how to find them

RNA molecules can fold into intricate shapes that can provide an additional layer of control of gene expression beyond that of their sequence. In this Review, we discuss the current mechanistic understanding of structures in 5' untranslated regions (UTRs) of eukaryotic mRNAs and the emerging methodologies used to explore them. These structures may regulate cap-dependent translation initiation through helicase-mediated remodelling of RNA structures and higher-order RNA interactions, as well as cap-independent translation initiation through internal ribosome entry sites (IRESs), mRNA modifications and other specialized translation pathways. We discuss known 5' UTR RNA structures and how new structure probing technologies coupled with prospective validation, particularly compensatory mutagenesis, are likely to identify classes of structured RNA elements that shape post-transcriptional control of gene expression and the development of multicellular organisms.

[Surgical Treatment of High-Grade High-Dysplastic Spondylolistheses in Young Patients - Prospective Monocentric Study of 29 Patients]

PURPOSE OF THE STUDY An optimal technique to surgically treat high-grade high-dysplastic (HG HD)spondylolistheses remains disputable. There are multiple surgical procedures described, ranging from a simple posterior fusion in situ without fixation through a standalone anterior lumbar interbody fusion with the oblique insertion of a structural bonegraft to instrumented full reduction and 360-degree fusion. At our department, preference is given to the instrumented monosegmental reduction and fixation by a fixator with Schanz screws. The aim of this paper is a prospective clinical and radiological evaluation of the group of operated patients below 30 years of age with HG HD spondylolisthesis with a slip greater than 50%. MATERIAL AND METHODS In the period from 11/2007 to 2/2017, a total of 29 patients with HG HD spondylolisthesis always of the L5-S1 segment were treated at the Department of Spinal Surgery of the First Faculty of Medicine of the Charles University and the Teaching Hospital Motol. They were 10 men and 19 women aged 10 to 28 years, with the mean age of 18.4 years. In 27 patients reduction and single-segment fixation of L5-S1 were performed as primary treatment, in one case decompression and noninstrumented-fusion only was carried out and in one case in situ fixation of L4-L5-S1 for distinctive osteoporosis. RESULTS The average duration of posterior surgery without the reconstruction of the anterior column was 88.9 min, in case of anterior fusion it was 46.6 min and in case of only posterior approach and fusion with the reconstruction of the anterior column it was 141.5 min. The average blood loss in the posterior fusion without the reconstruction of the anterior column reached 384.3 ml, in the stand-alone anterior fusion it was 21.6 ml. and in the posterior fusion with the reconstruction of the anterior column 430.0 ml. In 27 patients in whom the reduction was carried out, a shift of the L5 vertebral body observed on the CT scan prior to the surgery was 64.3% on average, while postoperatively and also at 6 months after the surgery during the follow-up examination it was 8.1%. A clear bone posterolateral fusion was found by the CT examination after 4-6 months in all 29 patients (100%, N = 29), while bone intersomatic fusion was reported in 25 cases (96.2%, N = 26). Altogether 6.9% of residual neurological deficits were observed. The statistical processing of VAS values for lumbar back pain and ODI values before the surgery and after two years confirmed a significant improvement of the clinical condition (p < 0.001). When asked whether they would undergo the same surgery with their current experience with the treatment, all the 29 patients answered "yes" and stressed the functional as well as the aesthetic results of the surgery. DISCUSSION In agreement with the other authors, the PT, SS and PI values are measured and we consider the SA, SDSG LSA and Dubousset s LSA assessments to be essential. All the measured values showed statistically significant changes postoperatively, only the pelvic incidence(PI) value remained unchanged. In patients with HG HD spondylolisthesis, we prefer reduction and the 360-degree monosegmental fusion, in the case of sacral osteotomy always using the posterior approach, in the cases where osteotomy is not performed using the next anterior approach. Even in the cases of the most severe deformities, we prefer to maintain the body of L5 and, where necessary, rather shorten the sacrum, which in our opinion leads to a better aesthetic result. CONCLUSIONS The reduction by single-segment instrumentation is a suitable alternative to the surgical therapy of HG HD spondylolistheses in young patients. It provides a high success rate of bone fusion and good clinical results including the aesthetic aspects. The complications associated with full reduction are not markedly higher than in other surgical techniques. Key words:spondylolisthesis, HGHD, high-grade, high-dysplastic, reduction, pelvic incidence, pelvic tilt, sacral slope.

Heterogeneous Ribosomes Preferentially Translate Distinct Subpools of mRNAs Genome-wide

Emerging studies have linked the ribosome to more selective control of gene regulation. However, an outstanding question is whether ribosome heterogeneity at the level of core ribosomal proteins (RPs) exists and enables ribosomes to preferentially translate specific mRNAs genome-wide. Here, we measured the absolute abundance of RPs in translating ribosomes and profiled transcripts that are enriched or depleted from select subsets of ribosomes within embryonic stem cells. We find that heterogeneity in RP composition endows ribosomes with differential selectivity for translating subpools of transcripts, including those controlling metabolism, cell cycle, and development. As an example, mRNAs enriched in binding to RPL10A/uL1-containing ribosomes are shown to require RPL10A/uL1 for their efficient translation. Within several of these transcripts, this level of regulation is mediated, at least in part, by internal ribosome entry sites. Together, these results reveal a critical functional link between ribosome heterogeneity and the post-transcriptional circuitry of gene expression.

The Mammalian Ribo-interactome Reveals Ribosome Functional Diversity and Heterogeneity

During eukaryotic evolution, ribosomes have considerably increased in size, forming a surface-exposed ribosomal RNA (rRNA) shell of unknown function, which may create an interface for yet uncharacterized interacting proteins. To investigate such protein interactions, we establish a ribosome affinity purification method that unexpectedly identifies hundreds of ribosome-associated proteins (RAPs) from categories including metabolism and cell cycle, as well as RNA- and protein-modifying enzymes that functionally diversify mammalian ribosomes. By further characterizing RAPs, we discover the presence of ufmylation, a metazoan-specific post-translational modification (PTM), on ribosomes and define its direct substrates. Moreover, we show that the metabolic enzyme, pyruvate kinase muscle (PKM), interacts with sub-pools of endoplasmic reticulum (ER)-associated ribosomes, exerting a non-canonical function as an RNA-binding protein in the translation of ER-destined mRNAs. Therefore, RAPs interconnect one of life's most ancient molecular machines with diverse cellular processes, providing an additional layer of regulatory potential to protein expression.

An emerging role for the ribosome as a nexus for post-translational modifications

The ribosome is one of life's most ancient molecular machines that has historically been viewed as a backstage participant in gene regulation, translating the genetic code across all kingdoms of life in a rote-like fashion. However, recent studies suggest that intrinsic components of the ribosome can be regulated and diversified as a means to intricately control the expression of the cellular proteome. In this review, we discuss advances in the characterization of ribosome post-translational modifications (PTMs) from past to present. We specifically focus on emerging examples of ribosome phosphorylation and ubiquitylation, which are beginning to showcase that PTMs of the ribosome are versatile, may have functional consequences for translational control, and are intimately linked to human disease. We further highlight the key questions that remain to be addressed to gain a more complete picture of the array of ribosome PTMs and the upstream enzymes that control them, which may endow ribosomes with greater regulatory potential in gene regulation and control of cellular homeostasis.

The p53 family members have distinct roles during mammalian embryonic development

The p53 tumor suppressor is a member of a multi-protein family, including the p63 and p73 transcription factors. These proteins can bind to the same consensus sites in DNA and activate the same target genes, suggesting that there could be functional redundancy between them. Indeed, double mutant mice heterozygous for any two family member-encoding genes display enhanced cancer phenotypes relative to single heterozygous mutants. However, whether the family members play redundant roles during embryonic development has remained largely unexplored. Although p53^-/-; p73^-/- mice are born and manifest phenotypes characteristic of each of the single mutants, the consequences of combined deficiency of p63 and either p53 or p73 have not been elucidated. To examine the functional overlap of p53 family members during development, we bred and analyzed compound mutant embryo phenotypes. We discovered that double knockout embryos and five allele knockout embryos only displayed obvious defects accounted for by loss of single p53 family members. Surprisingly, at mid-gestation (E11), we identified a single viable triple knockout embryo that appeared grossly normal. Together, these results suggest that the p53 family is not absolutely required for early embryogenesis and that p53 family members are largely non-redundant during early development.

Pervasive translational regulation of the cell signalling circuitry underlies mammalian development

The degree and dynamics of translational control during mammalian development remain poorly understood. Here we monitored translation of the mammalian genome as cells become specified and organize into tissues in vivo. This identified unexpected and pervasive translational regulation of most of the core signalling circuitry including Shh, Wnt, Hippo, PI3K and MAPK pathways. We further identify and functionally characterize a complex landscape of upstream open reading frames (uORFs) across 5'-untranslated regions (UTRs) of key signalling components. Focusing on the Shh pathway, we demonstrate the importance of uORFs within the major SHH receptor, Ptch1, in control of cell signalling and neuronal differentiation. Finally, we show that the expression of hundreds of mRNAs underlying critical tissue-specific developmental processes is largely regulated at the translation but not transcript levels. Altogether, this work reveals a new layer of translational control to major signalling components and gene regulatory networks that diversifies gene expression spatially across developing tissues.

[Giant Ganglioneuroma of the Spine and Mediastinum]

The case of a 15-year-old girl with a large ganglioneuroma in the mediastinum and spinal canal is presented. The tumour initially manifested as scoliosis. Its diagnosis was made on the basis of CT scanning and magnetic resonance imaging, and confirmed by thoracoscopic mediastinal biopsy. Radical tumour excision was indicated. The first stage involved removal of the tumour from the spinal canal through a posterior approach, and transpedicular fixation of the spinal column with correction of the curve. At the second-stage procedure, the tumour was removed from the pleural cavity and mediastinum through thoracotomy. At two years after surgery, the spondylodesis was completed with autologous bone grafts that healed within 6 months. At 3-year follow-up the patient was with neither clinical findings, nor subjective complains and imaging methods showed no signs of tumour recurrence.

KEY WORDS

ganglioneuroma, scoliosis, correction, thoracotomy, spinal canal, mediastinum.

Translating the genome in time and space: specialized ribosomes, RNA regulons, and RNA-binding proteins

A central question in cell and developmental biology is how the information encoded in the genome is differentially interpreted to generate a diverse array of cell types. A growing body of research on posttranscriptional gene regulation is revealing that both global protein synthesis rates and the translation of specific mRNAs are highly specialized in different cell types. How this exquisite translational regulation is achieved is the focus of this review. Two levels of regulation are discussed: the translation machinery and cis-acting elements within mRNAs. Recent evidence shows that the ribosome itself directs how the genome is translated in time and space and reveals surprising functional specificity in individual components of the core translation machinery. We are also just beginning to appreciate the rich regulatory information embedded in the untranslated regions of mRNAs, which direct the selective translation of transcripts. These hidden RNA regulons may interface with a myriad of RNA-binding proteins and specialized translation machinery to provide an additional layer of regulation to how transcripts are spatiotemporally expressed. Understanding this largely unexplored world of translational codes hardwired in the core translation machinery is an exciting new research frontier fundamental to our understanding of gene regulation, organismal development, and evolution.

Cis-regulatory RNA elements that regulate specialized ribosome activity

Recent evidence has shown that the ribosome itself can play a highly regulatory role in the specialized translation of specific subpools of mRNAs, in particular at the level of ribosomal proteins (RP). However, the mechanism(s) by which this selection takes place has remained poorly understood. In our recent study, we discovered a combination of unique RNA elements in the 5'UTRs of mRNAs that allows for such control by the ribosome. These mRNAs contain a Translation Inhibitory Element (TIE) that inhibits general cap-dependent translation, and an Internal Ribosome Entry Site (IRES) that relies on a specific RP for activation. The unique combination of an inhibitor of general translation and an activator of specialized translation is key to ribosome-mediated control of gene expression. Here we discuss how these RNA regulatory elements provide a new level of control to protein expression and their implications for gene expression, organismal development and evolution.

Differential Requirements for eIF4E Dose in Normal Development and Cancer

eIF4E, the major cap-binding protein, has long been considered limiting for translating the mammalian genome. However, the eIF4E dose requirement at an organismal level remains unexplored. By generating an Eif4e haploinsufficient mouse, we found that a 50% reduction in eIF4E expression, while compatible with normal development and global protein synthesis, significantly impeded cellular transformation. Genome-wide translational profiling uncovered a translational program induced by oncogenic transformation and revealed a critical role for the dose of eIF4E, specifically in translating a network of mRNAs enriched for a unique 5' UTR signature. In particular, we demonstrate that the dose of eIF4E is essential for translating mRNAs that regulate reactive oxygen species, fueling transformation and cancer cell survival in vivo. Our findings indicate eIF4E is maintained at levels in excess for normal development that are hijacked by cancer cells to drive a translational program supporting tumorigenesis.

Total En Bloc Spondylectomy of C3: A New Surgical Technique and Literature Review

PURPOSE OF THE STUDY

Radical resection of a vertebra is reserved only for specific tumors that invade the surrounding tissues and recur when not removed completely. The vertebra may be removed using a piecemeal technique or en bloc, using only two (in thoracolumbar spine) or more osteotomies (in cervical spine). We present our technique of en bloc resection of subaxial cervical vertebra for Ewing's sarcoma of C3, with preservation of all nerve roots and both vertebral arteries. To our knowledge, this surgical technique has not been reported in the English literature. The aim of this study is to describe the new technique of radical resection of subaxial cervical vertebra.

MATERIAL AND METHODS

A transoral biopsy of tumor tissue anterior to C2-C3 was performed in 8-year old boy, revealing a diagnosis of Ewing's sarcoma. The patient was started on neoadjuvant chemotherapy. After 6 chemotherapy cycles with the VIDE regimen, the soft-tissue component completely regressed, with the only a residual deposit in C3 vertebral body. Based on further multidisciplinary meeting, an en bloc spondylectomy of C3 was recommended, preferably with preservation of nerve roots and vertebral arteries. In August 2014, prior to the planned surgery, we performed another thorough examination of the patient using plain films, CT and MRI. Neither angiography nor embolization was performed. DESCRIPTION OF SURGICAL TECHNIQUE: The first stage of the operation consisted of resection of the posterior structures. We exposed the posterior elements of C2 to C4 by the mid-line incision. The C3 arch was without pathological changes. After partial resection of the C2 inferior and C4 superior articular processes we performed bilateral osteotomy in the region of the pedicle adjacent to the arch with a chisel and removed the whole of the C3 posterior arch. Subsequently we perforated the transverse foramina close to the pedicle, using fine Kerrison rongeurs. The lateral parts around vertebral arteries were left in situ. In the next step we used instrumentation with polyaxial screws to stabilize the C2-C4 section. After 19 days we performed the second stage surgery from an anterior approach with the removal of the anterior and lateral parts of the vertebra. We made a transverse incision anterior to the sternocleidomastoid between the internal carotid artery and the trachea on the right side at the level of C3 to expose the spine. We resected C2-C3 and C3-C4 intervertebral discs and then performed osteotomy with fine Kerrison rongeurs on both sides, again, close to the vertebral body. Subsequently, the vertebral body was released and extracted en bloc. In the next step, both vertebral arteries were mobilized and shifted medially and the lateral portions of the transverse processes were released and removed en bloc. The empty space was filled with solid allograft and the C2-C4 levels were bridged by the cervical plate in 2+1+2 configuration.

RESULTS

There were no complications during both surgeries. The follow-up CT examination 4 months after the operation revealed a clear bone fusion of C2-C4, both anteriorly between vertebral bodies and posteriorly between the arches. Clinically the patient has reached 8 month follow up and had no complaints, both he and his parents were satisfied. Physiotherapy is proceeding according to plan. The patient remains under supervision at our centre.

DISCUSSION

Total en bloc resection of a subaxial cervical vertebra with preservation of neural and vascular structures has been described in the English literature only once. In 2007 was published a total en bloc resection of C5 for chordoma, preserving the above mentioned structures. Authors removed the lamina en bloc after bilateral osteotomy. Transverse foramina were perforated by the Gigli saw and removed in piecemeal fashion, including the posterior tubercle. In the next step, they removed the vertebral body and the anterior tubercle from the anterior approach. However, their treatment differs from the technique described here and does not correspond fully to the principle of en bloc resection. Our surgical technique is based on a similar principle of performing several osteotomies without the use of high speed burr, while preserving all neural and vascular structures. The difference can be particularly seen in the approach to remove lateral parts of the transverse foramen, which are surrounding the vertebral arteries. We consider it as ideal to split the cervical vertebra by smooth cuts into four parts and remove them en bloc.

CONCLUSION

Total en bloc spondylectomy of a subaxial cervical vertebra with preservation of vertebral arteries and nerve roots is a radical surgery that should be used to treat only the most serious conditions. The risk of neurological deficit is outweighed by the benefits of oncological radicality. This new surgical technique has not yet been described and it is clear, that a larger cohort of patients is necessary to assess and potentially modify this technique so that it can be used more frequently in the future.

[Collet-Sicard Syndrome due to Occipital Condyle Fracture. Case Report]

The case of a 63-year-old man diagnosed with Collet-Sicard syndrome due to a fracture of the right occipital condyle is presented. The cause of injury was falling off a bicycle. Dysphonia and dysphagia were present from the moment of injury, with the gradual development of light atrophy of the tongue muscles and right trapezius muscle. The diagnosis was based on examination by CT and MRI methods, the act of swallowing and physical examination by an otorhinolaryngology specialist and a neurologist who confirmed the diagnosis of injury to cranial nerves IX, X and XI on the right side. The patient was treated conservatively with application of a Philadelphia collar. Dysphagia required PEG tube insertion. Skull fracture healing was evident on a CT scan at 3-month follow-up. However, dysphonia with dysphagia and muscle atrophy remained persistent.

RNA regulons in Hox 5' UTRs confer ribosome specificity to gene regulation

Emerging evidence suggests that the ribosome has a regulatory function in directing how the genome is translated in time and space. However, how this regulation is encoded in the messenger RNA sequence remains largely unknown. Here we uncover unique RNA regulons embedded in homeobox (Hox) 5' untranslated regions (UTRs) that confer ribosome-mediated control of gene expression. These structured RNA elements, resembling viral internal ribosome entry sites (IRESs), are found in subsets of Hox mRNAs. They facilitate ribosome recruitment and require the ribosomal protein RPL38 for their activity. Despite numerous layers of Hox gene regulation, these IRES elements are essential for converting Hox transcripts into proteins to pattern the mammalian body plan. This specialized mode of IRES-dependent translation is enabled by an additional regulatory element that we term the translation inhibitory element (TIE), which blocks cap-dependent translation of transcripts. Together, these data uncover a new paradigm for ribosome-mediated control of gene expression and organismal development.

Tailor made protein synthesis for HSCs

Translation control is a prevalent form of gene expression regulation in developmental and stem cell biology. A recent paper by Signer et al. (2014) measures protein synthesis in the mouse hematopoietic compartment and reveals the importance of diminished protein production for maintaining hematopoietic stem cell function and restraining oncogenic potential.

[Axial lumbar interbody fusion: prospective monocentric study]

PURPOSE OF THE STUDY

The aim of this prospective study was to evaluate clinical and radiographic results in the patients who underwent L5-S1 fixation using the technique of percutaneous lumbar interbody fusion (AxiaLIF).

MATERIAL

The study comprised 23 patients, 11 women and 12 men, who ranged from age of 21 to 63 years, with an average of 48.2 years. In all patients surgical posterior stabilisation involving the L5-S1 segment had previously been done. The initial indications for surgery were L5-S1 spondylolisthesis in 20 and L5-S1 spondylosis and stenosis in three patients.

METHODS

The AxiaLIF technique for L5-S1 fixation was indicated in overweight patients and in those after repeated abdominal or retroperitoneal surgery. A suitable position and shape of the sacrum or lumbosacral junction was another criterion. The patients were evaluated between 26 and 56 months (average, 40.4 months) after primary surgery and, on the basis of CT and radiographic findings, bone union and lumbosacral junction stability were assessed. The clinical outcome was investigated using the ODI and VAS systems and the results were statistically analysed by the Wilcoxon test for paired samples with statistical significance set at a level of 0.05.

RESULTS

The average VAS value was 6.6 before surgery and, after surgery, 5.2 at three months, 4.2 at six months, 3.1 at one year, 2.9 at two years and 2.1 at three years (n=18). At two post-operative years, improvement in the VAS value by 56.1% was recorded. The average pre-operative ODI value was 25.1; the post-operative values were 17.0 at six months, 12.3 at one year, 10.6 at two years and 8.2 at three years (n=18). At two years after surgery the ODI value improved by 57.8%. To the question concerning their willingness to undergo, with acquired experience, surgery for the same diagnosis, 21 patients (91.3%) gave an affirmative answer. Neither screw breakage nor neurovascular damage or rectal injury was found. CT scans showed complete interbody bone fusion in 22 of the 23 patients (95.6%), In one patient the finding was not clear. Also, posterolateral fusion was achieved in all but one patients (95.6%). A stable L5-S1 segment was found in all patients at all follow-up intervals. The improvement in both VAS and ODI values was statistically significant.

DISCUSSION

In addition to indications usual in degenerative disc disease, overweight patients, those who had repeated trans- or retroperitoneal surgery in the L5-S1 region or who underwent long posterior fixation to stabilise the caudal margin of instrumentation are indicated for the AxiaLIF procedure. The clinical results of our study are in agreement with the conclusions of other studies and are similar to the outcomes of surgery using other types of fusion or dynamic stabilisation for this diagnosis. The high rate of fusion in our group is affected by use of a rigid transpedicular fixator together with posterolateral arthrodesis. On the other hand, no negative effects of only synthetic bone applied to interbody space were recorded.

CONCLUSIONS

The percutaneous axial pre-sacral approach to the L5-S1 interbody space with application of a double-treaded screw is another option for the management of this much strained segment. The technique is useful particularly when contraindications for conventional surgical procedures are present in patients with anatomical anomalies, in overweight patients or in those who have had repeated surgery in the region. Clinical outcomes and the success rate for L5-S1 bone fusion are comparable with conventional techniques. Complications are rare but their treatment is difficult.

Barriers for progress in salt reduction in the general population. An international study

Salt reduction is important for reducing hypertension and the risk of cardiovascular events, nevertheless worldwide salt intakes are above recommendations. Consequently strategies to reduce intake are required, however these require an understanding of salt intake behaviours to be effective. As limited information is available on this, an international study was conducted to derive knowledge on salt intake and associated behaviours in the general population. An online cohort was recruited consisting of a representative sample from Germany, Austria, United States of America, Hungary, India, China, South Africa, and Brazil (n=6987; aged 18-65 years; age and gender stratified). Participants completed a comprehensive web-based questionnaire on salt intake and associated behaviours. While salt reduction was seen to be healthy and important, over one third of participants were not interested in salt reduction and the majority were unaware of recommendations. Salt intake was largely underestimated and people were unaware of the main dietary sources of salt. Participants saw themselves as mainly responsible for their salt intake, but also acknowledged the roles of others. Additionally, they wanted to learn more about why salt was bad for health and what the main sources in the diet were. As such, strategies to reduce salt intake must raise interest in engaging in salt reduction through improving understanding of intake levels and dietary sources of salt. Moreover, while some aspects of salt reduction can be globally implemented, local tailoring is required to match level of interest in salt reduction. These findings provide unique insights into issues surrounding salt reduction and should be used to develop effective salt reduction strategies and/or policies.

[Unstable injuries to the upper cervical spine in children and adolescents]

PURPOSE OF THE STUDY

Injuries to the upper cervical spine in children are rare and account for 0.6 to 9.5% of all cervical spine injuries. We present a detailed analysis of the children and adolescents with unstable upper cervical spine injuries treated at our spinal centre.

MATERIAL

During 16 years of follow-up, unstable injury to the upper cervical spine was recorded in 23 children and adolescents. Two patients (8.7%) were treated conservatively and 21 (91.3%) underwent surgery. The patients were allocated by age to three groups: 0-9 year, 10-14 year and 15-18 year categories. Twenty patients were seen at the final clinical and radiographic follow-up. One patient died at 62 months after surgery and two patients unfit for transport were evaluated on the basis of mailed interviews. The interval between injury and final evaluation ranged from 6 to 137 months, with an average of 53.4 months.

METHODS

The patients treated conservatively first wore a Philadelphia collar, then a custom-made brace, and eventually a soft Schanze cervical collar to finish the healing process. Application of a halo vest was considered a surgical procedure and was used only in very small children. In unstable odontoid fractures, direct osteosynthesis with two cannulated titanium screws was performed from the anterior approach in older children while, in small children, transoral or submandibular retropharyngeal decompression to treat spinal stenosis caused by bone fragments was carried out and a halo vest was applied. Hangman's fractures were treated by anterior cervical discectomy, fusion with bone graft and anterior plate fixation. The other types of unstable fractures were managed from the posterior approach by occipitocervical fixation, atlantoaxial fixation or instrumented fusion extended caudally. The patients characteristics included gender, age, mechanism of injury, type of injury, neurological findings, type of therapy or surgery, complications and treatment outcome. Neurological status was evaluated using the Frankel classification.

RESULTS

The patient group comprised 14 boys (60.9%) and nine girls (39.1%), which gave a gender ratio of 3 : 2. The age of patients at injury ranged from 2 to 18 years, with an average of 11 years and 6 months. The most frequent injuries included rotational or vertical atlantoaxial dislocation in eight (34.8%) and odontoid fractures in seven (30.4%) patients; atlas fracture was recorded in three (13.0%) and hangman's fracture also in three (13.0%) patients; occipitocervical displacement was found in one (4.3%) and complex atlantoaxial fracture also in one patient (4.3%). At the time of injury, 17 patients (73.9%) had no neurological deficit (Frankel grade E), three had Frankel grade A (one paraplegic with a concomitant T5 spinal cord injury) and three had Frankel grade D neurological deficits. Of the six patients with neurological deficit, two showed improvement by one or two Frankel grades. The method of dorsal atlantoaxial fixation was used in eight patients (Magerl fixation in 2 and Harms method in 6). Direct osteosynthesis of an odontoid fracture was performed in four patients, halo fixation was applied in four, C2-C3 discectomy with tricortical bone grafting and plating was carried out in three, occipitocervical fixation was used in three patients, and direct atlas osteosynthesis, simple decompression and simple non-instrumented dorsal spondylodesis each was performed in one patient. Neither intra-operative complications nor post-operative complications related to the surgical technique were recorded. Osteoarthritis or bone non-union, as late post-operative complications, were found in two patients. All other patients showed bone healing by first intention in the desired extent. Superficial or deep wound infections were not recorded.

DISCUSSION

In the first age category, the number of boys and girls with injuries to the upper cervical spine was equal while, in the third one, the boys outnumbered the girls more than twice. Of the 23 patients, 91.3% were surgically treated; the anterior approach was used in approximately one third of the patients and the posterior approach in the rest of them. The high number of surgical interventions is due to the fact that the most serious paediatric spinal injuries are referred to our centre.

CONCLUSIONS

1. Injuries to the upper cervical spine are most frequently found in the youngest children and in adolescents who, however, frequently have injury also to the lower cervical spine. 2. Neurological deficit is relatively frequent but has a better prognosis than in adults. The youngest children with mild deficits have the best prognosis. 3. The mortality rate in young children with upper cervical spine injuries is evidently high, mostly due to associated head, chest and abdomen trauma 4. Therapy, particularly in small children, is strictly individual.

Specialized ribosomes: a new frontier in gene regulation and organismal biology

Historically, the ribosome has been viewed as a complex ribozyme with constitutive rather than intrinsic regulatory capacity in mRNA translation. However, emerging studies reveal that ribosome activity may be highly regulated. Heterogeneity in ribosome composition resulting from differential expression and post-translational modifications of ribosomal proteins, ribosomal RNA (rRNA) diversity and the activity of ribosome-associated factors may generate 'specialized ribosomes' that have a substantial impact on how the genomic template is translated into functional proteins. Moreover, constitutive components of the ribosome may also exert more specialized activities by virtue of their interactions with specific mRNA regulatory elements such as internal ribosome entry sites (IRESs) or upstream open reading frames (uORFs). Here we discuss the hypothesis that intrinsic regulation by the ribosome acts to selectively translate subsets of mRNAs harbouring unique cis-regulatory elements, thereby introducing an additional level of regulation in gene expression and the life of an organism.

[Surgical treatment for atlantoaxial osteoarthritis (AAOA): a prospective study of twenty-seven patients]

PURPOSE OF THE STUDY

Atlantoaxial osteoarthritis (AAOA) is a clinical syndrome with signs distinctly different from those of degenerative sub - axial spine disease. Its diagnosis may long be delayed, partly because of insufficient knowledge and partly due to difficulties in interpreting both anteroposterior and lateral radiographs. The aim of this prospective study was to evaluate the first 27 AAOA patients treated at our department.

MATERIAL

From 2001 we performed atlantoaxial fixation with fusion in a total of 29 patients with painful arthritis of the atlanto axial complex. The 27 patients treated before the end of 2010 were enrolled in the study and analysed in detail. This group included 13 women and 14 men aged between 35 and 72 years, with an average age of 53.5 years. In all patients atlanto - axial fixation was performed using the polyaxial screw-rod system according to Harms.

METHODS

The patients were followed up at 6 and 12 weeks, 6 and 12 months and then once a year after surgery. X-ray examinations were done at the same intervals as clinical examinations; functional radiographs were made at 12 to 14 weeks after surgery. The definitive analysis of the group was made in the range of 4 to 59 months (average, 25.7 months) after the primary operation. Patients' subjective evaluation was based on NPDI and VAS scores and a question of whether the patient would undergo the surgery again. Objective evaluation included clinical outcomes - pain and neurological findings; radiographic results - stability and healing of C1-C2 fusion; and complications during surgery and in early and late postoperative periods. As intra-operative complications were regarded those associated with the surgical approach, nerve injury and vertebral artery injury. Early post-operative complications included poor wound healing and changes in the patient's neurological status, late complications included instrumentation failure and infection. Patients' clinical status (NPDI, VAS) was statistically evaluated using the one-way ANOVA.

RESULTS

The mean VAS score was pre-operatively 7.0 and post-operatively 5.6 at 3 months, 5.0 at 6 months, 5.1 at 1 year; 3.9 at 2 years and 4.0 at 3 years. The mean NPDI value was pre-operatively 39.6 and post-operatively 38.7 at 3 months, 36.0 at 6 months, 34.5 at 1 year, 34.3 at 2 years and 33.1 at 3 years. The question of willingness to undergo the same operation again was answered in the affirmative by 21 patients (77.8%), in the negative by five (18.5%) and one patient did not know (3.7%). Complete bone fusion, as assessed by radiography or CT scanning, was achieved in 26 out of 27 patients (96.3%). In one patient the result was ambiguous but, at 3 months as well as the next follow-ups, C1-C2 complex stability was found.

DISCUSSION

All patients in our group underwent a unified system of clinical, radiological, CT and MRI examination. In the decision-making process, emphasis was placed on a correlation of clinical findings with CT scanning results. All patients were operated on from the posterior approach using the Harms method, and radiological outcomes were similar to those of Grob et al. who used the Magerl's technique of C1-C2 fixation. The VAS and NPDI scores demonstrated significant improvement as early as 3 post-operative months, with still further improvement in the following period. The stable clinical status of the patients was achieved at 2 years after surgery. From the practical standpoint we were interested in an answer to the question of whether the patients would be willing to undergo the procedure again. Almost 80% of affirmative answers testified to the correct choice of treatment. The values found corresponded to those reported by Grob at al.

CONCLUSIONS

Patients with painful osteoarthritis refractory to conservative treatment will benefit from atlantoaxial fixation and fusion. For the patient, restricted cervical rotation is acceptable in return for pain relief. From the surgical point of view, the risk of complications associated with the operative technique did not exceed a tolerable rate.

[Spinal cord concussion: a retrospective study of twenty-four patients]

PURPOSE OF THE STUDY

Spinal cord concussion is characterised as fully reversible, temporary inhibition of conductive function due to trauma, without signs of structural changes. Although neurological deficit is usually related to the severity of spinal injury, this is different in spinal cord concussion. The aim of this retrospective study was to evaluate a group of 24 patients with spinal cord concussion, to design a diagnostic algorithm and propose an effective therapy with a good prognosis for the patients.

MATERIAL

We reviewed clinical records of 9 768 patients hospitalised at the Department of Spinal Surgery, University Hospital in Motol, from September 2002 till December 2010, and of 457 patients treated at other departments of the Hospital between January 2008 and December 2010; this was a total of 10 225 patients. The data were retrospectively analysed and only the patients with a clear history of trauma and subsequent conservative therapy were selected to comprise a group characterised by the generally known criteria of spinal cord concussion: (1) spinal injury with immediate neurological deficit of varying degree; (2) neurological deficit corresponding to the level of spinal injury; (3) recovery of neurological function within 72 hours of injury; (4) no morphological evidence of injury to the spinal structures obtained by imaging methods. This group comprised 24 patients.

METHODS

The patients were followed up from 6 to 95 months, with a mean of 46 months and a median of 48 months, at intervals of 6 and 12 weeks and 6 and 12 months after injury, and then every following year. The recorded information included the patient's age at the time of injury, their gender, the mechanism of injury, reports on alcohol consumption, the first detected neurological deficit, its development immediately after injury, during the hospital stay and at follow-ups in the out-patient department, methylprednisolone administration according to the National Acute Spinal Cord Injury Study (NASCIS) 2, and findings of imaging methods, particularly MRI.

RESULTS

Our group consisted of 22 men (91.7%) and two women (8.3%), with an average age of 29 years; the average age was 30 years in men and 18.5 years in women. Seven patients (29.2%) were younger than 18 years, with an average of 16.14 years; the remaining 17 patients (70.8%) were older than 18 years, with an average of 34.35 years. The major mechanisms of injury included falls from a height in 10 patients (41.7%) and injury due to alcohol consumption in five patients (20.1%). Clinical findings involved lesions of the medullary cone in 12 (50.0%), cervical spinal cord in seven (29.2%) and thoracic spinal cord in five (20.8%) patients. Motor function deficit was present in all patients, of whom 10 (41.2%) showed a complete loss of motor function. Impaired sensory function was found in 21 (87.5%) patients. One patient had perianal and genital sensory deficit and one (4.2%) had urinary retention. Neither radiograms nor CT scans showed traumatic changes in any of the patients; MRI findings free of any traumatic spinal changes were recorded in 21 patients (87.5%). One patient had oedema of the T5 and T8 vertebral bodies. No complications were recorded. All patients experienced rapid resolution of neurological deficit, which occurred within 6 hours of injury in two (8.4%), within 12 hours in two (8.4%), within 24 hours in 12 (50.0%) and within 48 hours in six (25.0%) patients, and later than 48 hours after injury in two patients (8.4%). However, recovery always occurred within 72 hours of injury.

DISCUSSION

A good prognosis for patients with this injury is supported by our findings, because all patients experienced rapid resolution of neurological deficit within 72 hours of injury. This result is in agreement with the relevant international studies reporting no serious complications associated with spinal trauma. There are no clear recommendations for administration of high doses of methylprednisolone according to the NASCIS system.

CONCLUSIONS

Spinal cord concussion is not a frequent injury; in our study, it accounted for 3.54% of the patients with trauma histories out of the total number of 678 patients, or for 2.40% out of 997 injured spinal levels. The first steps should be the same as in any other injury to the spinal cord. An early examination of the patient with imaging methods including MRI is of primary importance. At present administration of methylprednisolone according to the NASCIS system is disputable. The patient diagnosed with spinal cord concussion has a good prognosis, with rehabilitation as the main therapeutic approach.