Unidad de Investigación en cuidados y servicios de salud (Investén-isciii)

OBJECTIVES: To determine the association of hospital nursing skill mix with patient mortality, patient ratings of their care and indicators of quality of care. DESIGN: Cross-sectional patient discharge data, hospital characteristics and nurse and patient survey data were merged and analysed using generalised estimating equations (GEE) and logistic regression models. SETTING: Adult acute care hospitals in Belgium, England, Finland, Ireland, Spain and Switzerland. PARTICIPANTS: Survey data were collected from 13 077 nurses in 243 hospitals, and 18 828 patients in 182 of the same hospitals in the six countries. Discharge data were obtained for 275 519 surgical patients in 188 of these hospitals. MAIN OUTCOME MEASURES: Patient mortality, patient ratings of care, care quality, patient safety, adverse events and nurse burnout and job dissatisfaction. RESULTS: Richer nurse skill mix (eg, every 10-point increase in the percentage of professional nurses among all nursing personnel) was associated with lower odds of mortality (OR=0.89), lower odds of low hospital ratings from patients (OR=0.90) and lower odds of reports of poor quality (OR=0.89), poor safety grades (OR=0.85) and other poor outcomes (0.80<OR<0.93), after adjusting for patient and hospital factors. Each 10 percentage point reduction in the proportion of professional nurses is associated with an 11% increase in the odds of death. In our hospital sample, there were an average of six caregivers for every 25 patients, four of whom were professional nurses. Substituting one nurse assistant for a professional nurse for every 25 patients is associated with a 21% increase in the odds of dying. CONCLUSIONS: A bedside care workforce with a greater proportion of professional nurses is associated with better outcomes for patients and nurses. Reducing nursing skill mix by adding nursing associates and other categories of assistive nursing personnel without professional nurse qualifications may contribute to preventable deaths, erode quality and safety of hospital care and contribute to hospital nurse shortages.

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BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed psychiatric disorders in childhood. A wide variety of treatments have been used for the management of ADHD. We aimed to compare the efficacy and safety of pharmacological, psychological and complementary and alternative medicine interventions for the treatment of ADHD in children and adolescents. METHODS AND FINDINGS: We performed a systematic review with network meta-analyses. Randomised controlled trials (≥ 3 weeks follow-up) were identified from published and unpublished sources through searches in PubMed and the Cochrane Library (up to April 7, 2016). Interventions of interest were pharmacological (stimulants, non-stimulants, antidepressants, antipsychotics, and other unlicensed drugs), psychological (behavioural, cognitive training and neurofeedback) and complementary and alternative medicine (dietary therapy, fatty acids, amino acids, minerals, herbal therapy, homeopathy, and physical activity). The primary outcomes were efficacy (treatment response) and acceptability (all-cause discontinuation). Secondary outcomes included discontinuation due to adverse events (tolerability), as well as serious adverse events and specific adverse events. Random-effects Bayesian network meta-analyses were conducted to obtain estimates as odds ratios (ORs) with 95% credibility intervals. We analysed interventions by class and individually. 190 randomised trials (52 different interventions grouped in 32 therapeutic classes) that enrolled 26114 participants with ADHD were included in complex networks. At the class level, behavioural therapy (alone or in combination with stimulants), stimulants, and non-stimulant seemed significantly more efficacious than placebo. Behavioural therapy in combination with stimulants seemed superior to stimulants or non-stimulants. Stimulants seemed superior to behavioural therapy, cognitive training and non-stimulants. Behavioural therapy, stimulants and their combination showed the best profile of acceptability. Stimulants and non-stimulants seemed well tolerated. Among medications, methylphenidate, amphetamine, atomoxetine, guanfacine and clonidine seemed significantly more efficacious than placebo. Methylphenidate and amphetamine seemed more efficacious than atomoxetine and guanfacine. Methylphenidate and clonidine seemed better accepted than placebo and atomoxetine. Most of the efficacious pharmacological treatments were associated with harms (anorexia, weight loss and insomnia), but an increased risk of serious adverse events was not observed. There is lack of evidence for cognitive training, neurofeedback, antidepressants, antipsychotics, dietary therapy, fatty acids, and other complementary and alternative medicine. Overall findings were limited by the clinical and methodological heterogeneity, small sample sizes of trials, short-term follow-up, and the absence of high-quality evidence; consequently, results should be interpreted with caution. CONCLUSIONS: Clinical differences may exist between the pharmacological and non-pharmacological treatment used for the management of ADHD. Uncertainties about therapies and the balance between benefits, costs and potential harms should be considered before starting treatment. There is an urgent need for high-quality randomised trials of the multiple treatments for ADHD in children and adolescents. PROSPERO, number CRD42014015008.

Klebsiella pneumoniae is a common cause of gram-negative bacterial nosocomial pneumonia. Two surface polysaccharides, lipopolysaccharide (LPS) O side chain and capsular polysaccharide (CPS), are critical for the microorganism in causing sepsis, but little is known about their role in pneumonia. To investigate their contribution in the pathogenesis of K. pneumoniae pneumonia, we characterized the host response to bacterial challenge with a highly virulent clinical isolate or with isogenic insertion-duplication mutants deficient in CPS or LPS O side chain in a murine model of pneumonia. Animals challenged intratracheally with the wild-type or LPS O side chain-deficient strain developed pneumonia and became bacteremic before death. Extensive lung lesions as well as pleuritis, vasculitis, and edema were observed by histopathological examination, and polymorphonuclear infiltration was also demonstrated. In contrast, none of the animals challenged with the unencapsulated strain developed pneumonia or bacteremia. Examination of tissue from this group did not identify lung lesions, and none of the infected animals died. Analysis of the early host defense mechanisms that contributed to the clearance of the unencapsulated mutant showed that the levels of C3 deposited on the unencapsulated mutant surface were threefold higher than those for the wild-type and LPS O side chain-deficient strains. Furthermore, phagocytosis of the unencapsulated mutant by human alveolar macrophages (AM) was more efficient than that of the wild-type and LPS O side chain-deficient strains. We conclude that CPS, but not LPS O side chain, is essential for Klebsiella pneumonia because it modulates the deposition of C3 and protects the microorganisms against human AM phagocytosis.

OBJECTIVE: To explore the attitudes of obstetricians to perform a caesarean section on maternal request in the absence of medical indication. DESIGN: Cluster sampling cross-sectional survey. SETTING: Neonatal Intensive Care Unit (NICU) associated maternity units in eight European countries. POPULATION: Obstetricians with at least 6 months clinical experience. METHODS: NICU-associated maternity units were chosen by census in Luxembourg, Netherlands and Sweden and by geographically stratified random sampling in France, Germany, Italy, Spain and UK. An anonymous, self-administered questionnaire was used for data collection. MAIN OUTCOME MEASURES: Obstetricians' willingness to perform a caesarean section on maternal request. RESULTS: One hundred and five units and 1,530 obstetricians participated in the study (response rates of 70 and 77%, respectively). Compliance with a hypothetical woman's request for elective caesarean section simply because it was 'her choice' was lowest in Spain (15%), France (19%) and Netherlands (22%); highest in Germany (75%) and UK (79%) and intermediate in the remaining countries. Using weighted multivariate logistic regression, country of practice (P<0.001), fear of litigation (P= 0.004) and working in a university-affiliated hospital (P= 0.001) were associated with physicians' likelihood to agree to patient's request. The subset of female doctors with children was less likely to agree (OR 0.29, 95% CI 0.20-0.42). CONCLUSIONS: The differences in obstetricians' attitudes are not founded on concrete medical evidence. Cultural factors, legal liability and variables linked to the specific perinatal care organisation of the various countries play a role. Greater emphasis should be placed on understanding the motivation, values and fears underlying a woman's request for elective caesarean delivery.

Von der priesterlichen Tora zum Pentateuch. Eine Untersuchung der Komposition des Buches Leviticus.

BACKGROUND: The increasing availability of gene sequences of prokaryotic species in samples extracted from all kind of locations allows addressing the study of the influence of environmental patterns in prokaryotic biodiversity. We present a comprehensive study to address the potential existence of environmental preferences of prokaryotic taxa and the commonness of the specialist and generalist strategies. We also assessed the most significant environmental factors shaping the environmental distribution of taxa. RESULTS: We used 16S rDNA sequences from 3,502 sampling experiments in natural and artificial sources. These sequences were taxonomically assigned, and the corresponding samples were also classified into a hierarchical classification of environments. We used several statistical methods to analyze the environmental distribution of taxa. Our results indicate that environmental specificity is not very common at the higher taxonomic levels (phylum to family), but emerges at lower taxonomic levels (genus and species). The most selective environmental characteristics are those of animal tissues and thermal locations. Salinity is another very important factor for constraining prokaryotic diversity. On the other hand, soil and freshwater habitats are the less restrictive environments, harboring the largest number of prokaryotic taxa. All information on taxa, samples and environments is provided at the envDB online database, http://metagenomics.uv.es/envDB. CONCLUSIONS: This is, as far as we know, the most comprehensive assessment of the distribution and diversity of prokaryotic taxa and their associations with different environments. Our data indicate that we are still far from characterizing prokaryotic diversity in any environment, except, perhaps, for human tissues such as the oral cavity and the vagina.

The human intestinal microbiota performs many essential functions for the host. Antimicrobial agents, such as antibiotics (AB), are also known to disturb microbial community equilibrium, thereby having an impact on human physiology. While an increasing number of studies investigate the effects of AB usage on changes in human gut microbiota biodiversity, its functional effects are still poorly understood. We performed a follow-up study to explore the effect of ABs with different modes of action on human gut microbiota composition and function. Four individuals were treated with different antibiotics and samples were taken before, during and after the AB course for all of them. Changes in the total and in the active (growing) microbiota as well as the functional changes were addressed by 16S rRNA gene and metagenomic 454-based pyrosequencing approaches. We have found that the class of antibiotic, particularly its antimicrobial effect and mode of action, played an important role in modulating the gut microbiota composition and function. Furthermore, analysis of the resistome suggested that oscillatory dynamics are not only due to antibiotic-target resistance, but also to fluctuations in the surviving bacterial community. Our results indicated that the effect of AB on the human gut microbiota relates to the interaction of several factors, principally the properties of the antimicrobial agent, and the structure, functions and resistance genes of the microbial community.

ABSTRACT I find that economically meaningless index labels cause stock returns to covary in excess of fundamentals. S&amp;P/Barra follow a simple mechanical procedure to define their Value and Growth indices. In doing so, they reclassify some stocks from Value to Growth even after their book‐to‐market ratios have risen, and vice versa. Such stocks begin to covary more with the index they join and less with the index they leave. Backdated constituent data from Barra reveal no such label‐related shifts in comovement during the 10 years prior to the actual introduction of the indices in 1992.

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is a commonly diagnosed neuropsychiatric disorder in childhood, but the frequency of the condition is not well established in many countries. The aim of the present study was to quantify the overall prevalence of ADHD among children and adolescents in Spain by means of a systematic review and meta-analysis. METHODS: PubMed/MEDLINE, IME, IBECS and TESEO were comprehensively searched. Original reports were selected if they provided data on prevalence estimates of ADHD among people under 18 years old in Spain and were cross-sectional, observational epidemiological studies. Information from included studies was systematically extracted and evaluated. Overall pooled-prevalence estimates of ADHD were calculated using random-effects models. Sources of heterogeneity were explored by means sub-groups analyses and univariate meta-regressions. RESULTS: Fourteen epidemiological studies (13,026 subjects) were selected. The overall pooled-prevalence of ADHD was estimated at 6.8% [95% confidence interval (CI) 4.9 - 8.8%] representing 361,580 (95% CI 260,550 - 467,927) children and adolescents in the community. There was significant heterogeneity (P < 0.001), which was incompletely explained by subgroup analyses and meta-regressions. CONCLUSIONS: Our findings suggest that the prevalence of ADHD among children and adolescents in Spain is consistent with previous studies conducted in other countries and regions. This study represents a first step in estimating the national burden of ADHD that will be essential to building evidence-based programs and services.

OBJECTIVE: The main objective of this study was to determine the relationship between the characteristics of nurses' work environments in hospitals in the Spanish National Health System (SNHS) with nurse reported quality of care, and how care was provided by using different shifts schemes. The study also examined the relationship between job satisfaction, burnout, sleep quality and daytime drowsiness of nurses and shift work. METHODS: This was a multicentre, observational, descriptive, cross-sectional study, centred on a self-administered questionnaire. The study was conducted in seven SNHS hospitals of different sizes. We recruited 635 registered nurses who worked on day, night and rotational shifts on surgical, medical and critical care units. Their average age was 41.1 years, their average work experience was 16.4 years and 90% worked full time. A descriptive and bivariate analysis was carried out to study the relationship between work environment, quality and safety care, and sleep quality of nurses working different shift patterns. RESULTS: 65.4% (410) of nurses worked on a rotating shift. The Practice Environment Scale of the Nursing Work Index classification ranked 20% (95) as favourable, showing differences in nurse manager ability, leadership and support between shifts (p=0.003). 46.6% (286) were sure that patients could manage their self-care after discharge, but there were differences between shifts (p=0.035). 33.1% (201) agreed with information being lost in the shift change, showing differences between shifts (p=0.002). The Pittsburgh Sleep Quality Index reflected an average of 6.8 (SD 3.39), with differences between shifts (p=0.017). CONCLUSIONS: Nursing requires shift work, and the results showed that the rotating shift was the most common. Rotating shift nurses reported worse perception in organisational and work environmental factors. Rotating and night shift nurses were less confident about patients' competence of self-care after discharge. The most common nursing care omissions reported were related to nursing care plans. For the Global Sleep Quality score, difference were found between day and night shift workers.

BACKGROUND: Percutaneous radiofrequency ablation (RFA) has gained popularity in the treatment of hepatocellular carcinoma (HCC). However, its role versus other conventional minimally invasive therapies is still a matter of debate. The purpose of this work is to analyse the efficacy and safety of RFA versus that of ethanol injection (PEI), the percutaneous standard approach to treat nonsurgical HCC. METHODS: Systematic review and meta-analysis of randomised or quasi-randomised controlled trials published up to August 2008 in PubMed, ISI Web of Science and The Cochrane Library. Overall survival, local recurrence rate and adverse effects were considered as primary outcomes. Studies were critically appraised and estimates of effect were calculated according to the random-effects model. Inconsistency across studies was evaluated using the I2 statistic. Sensitivity analyses were conducted to explore statistical heterogeneity. RESULTS: Six studies were eligible. The studies reported data on 396 patients treated by RFA and 391 treated by PEI. In general, subjects were in Child-Pugh class A (74%) and had unresectable HCC (mean size 2.5 cm). Mean follow-up was 25 +/- 11 months. The survival rate showed a significant benefit for RFA over PEI at one, two, three and four years. The advantage in survival increased with time with Relative Risk values of: 1.28 (95%CI:1.12-1.45) and 1.24 (95%CI:1.05-1.48) for RFA versus PEI at 3- and 4-years respectively. Likewise, RFA achieved significantly lower rates of local recurrence (RR: 0.37, 95%CI: 0.23-0.59). The overall rate of adverse events was higher with RFA (RR:2.55, 95%CI: 1.8-3.6) yet no significant differences were found concerning major complications (RR:1.85, 95%CI: 0.68-5.01). There was not enough evidence supporting a better cost-effectiveness ratio for RFA compared to PEI. CONCLUSION: Available evidence from adequate quality controlled studies support the superiority of RFA versus PEI, in terms of better survival and local control of the disease, for the treatment of patients with relatively preserved liver function and early-stage non-surgical HCC. However, the higher rate of adverse events displayed is something that will have to be tested with appropriate weighting of the possible benefits in each individual case. Overall cost-effectiveness of RFA needs further evaluation.

BACKGROUND: Nursing educators need rigorously developed instruments to assess competency in evidence based practice (EBP) at undergraduate level. This concept is defined as the capability to choose and use an integrated combination of knowledge, skills and attitudes with the intention to develop a task in a certain context. Also, we understand that EBP is gaining knowledge and skills, as well as increasing positive attitudes toward EBP that will promote a change in behaviour to implement EBP in practice. This study aims to develop a psychometric test of the Evidence Based Practice Evaluation Competence Questionnaire (EBP-COQ) among undergraduate nursing students. METHODS: The questionnaire was developed by item generation through a review of scientific literature and focus groups. The instrument was validated in terms of content validity through an expert review. The EBP-COQ was administered to a cohort of nursing students (n =100) to evaluate test reliability and select the best items. Psychometric properties of the final instrument were assessed in a sample of 261 nursing students. RESULTS: The EBP-COQ consisted of 25 items. A factorial analysis grouped the items into the three categories that define competence relating to EBP: attitude, knowledge and skills. Cronbach's alpha was 0.888 for the entire questionnaire. The factor solution explained 55.55% of the variance. CONCLUSIONS: EBP-COQ appears to measure with adequate reliability the attributes of undergraduate nursing students' competence in EBP. The instrument is quick to disseminate and easy to score, making it a suitable instrument for nursing educators to evaluate students' self-perceived competence in EBP.

Stimulation of endothelial cells (ECs) with TNF-α causes an increase in the expression of bone morphogenetic protein-2 (BMP-2) and the production of endothelial microparticles (EMPs). BMP-2 is known to produce osteogenic differentiation of vascular smooth muscle cells (VSMCs). It was found that EMPs from TNF-α-stimulated endothelial cells (HUVECs) contained a significant amount of BMP-2 and were able to enhance VSMC osteogenesis and calcification. Calcium content was greater in VSMCs exposed to EMPs from TNF-α-treated HUVECs than EMPs from nontreated HUVECs (3.56 ± 0.57 vs. 1.48 ± 0.56 µg/mg protein; P < 0.05). The increase in calcification was accompanied by up-regulation of Cbfa1 (osteogenic transcription factor) and down-regulation of SM22α (VSMC lineage marker). Inhibition of BMP-2 by small interfering RNA reduced the VSMC calcification induced by EMPs from TNF-α-treated HUVECs. Similar osteogenic capability was observed in EMPs from both patients with chronic kidney disease and senescent cells, which also presented a high level of BMP-2 expression. Labeling of EMPs with CellTracker shows that EMPs are phagocytized by VSMCs under all conditions (with or without high phosphate, control, and EMPs from TNF-α-treated HUVECs). Our data suggest that EC damage results in the release of EMPs with a high content of calcium and BMP-2 that are able to induce calcification and osteogenic differentiation of VSMCs.

OBJECTIVES: To describe the molecular and population-level characterization of a selected group of OXA-48-like-producing Klebsiella pneumoniae isolates collected in Spain between January 2011 and May 2012. METHODS: During the study period, 151 OXA-48-like-producing K. pneumoniae isolates were collected from 10 hospitals in six different Spanish regions. From these, a representative sample of 21 isolates that caused hospital outbreaks and single infections was selected for further in-depth analysis. Molecular epidemiology was investigated using PFGE and multilocus sequence typing (MLST). Resistance genes were characterized by PCR and sequencing. Plasmids carrying bla(OXA-48-like) were studied by PFGE with S1 nuclease digestion. RESULTS: All 21 isolates had ertapenem MICs ≥ 1 mg/L, but 47.6% remained susceptible to imipenem and meropenem; bla(OXA-48) was identified in 19 isolates (90.5%) and the novel bla(OXA-244) and bla(OXA-245) genes were detected in 1 isolate each. With one exception, all isolates that contained bla(OXA-48-like) also contained bla(CTX-M-15). PFGE typing revealed six clusters comprising isolates that belonged to MLST types ST11, ST16, ST392, ST405, ST437 and ST663, respectively. Two main clusters were identified: PFGE cluster 1 (12 isolates, belonging either to ST405 or ST663, from seven hospitals), and PFGE cluster 2 (4 ST16 isolates from two hospitals). Six of seven donor isolates conjugated successfully; bla(OXA-48-like) (but not bla(CTX-M-15)) was carried on ≈ 60 kb Inc L/M plasmids. CONCLUSIONS: Multidrug-resistant K. pneumoniae producing OXA-48-like carbapenemase are emerging as important pathogens in Spain due to intra- and inter-hospital, clonal and non-clonal dissemination.

Community-acquired pneumonia (CAP) is a common cause of morbidity among children in developed countries and accounts for an incidence of 10-40 cases per 1000 children in the first 5 years of life. Given the clinical, social and economic importance of CAP, there is general agreement that prompt and adequate therapy is essential to reduce the impact of the disease. The aim of this discussion paper is to consider critically the available data concerning the treatment of uncomplicated pediatric CAP and to consider when, how and for how long it should be treated. This review has identified the various reasons that make it difficult to establish a rational approach to the treatment of pediatric CAP, including the definition of CAP, the absence of a pediatric CAP severity score, the difficulty of identifying the etiology, limited pharmacokinetic (PK)/pharmacodynamic (PD) studies, the high resistance of the most frequent respiratory pathogens to the most widely used anti-infectious agents and the lack of information concerning the changes in CAP epidemiology following the introduction of new vaccines against respiratory pathogens. More research is clearly required in various areas, such as the etiology of CAP and the reasons for its complications, the better definition of first- and second-line antibiotic therapies (including the doses and duration of parenteral and oral antibiotic treatment), the role of antiviral treatment and on how to follow-up patients with CAP. Finally, further efforts are needed to increase vaccination coverage against respiratory pathogens and to conduct prospective studies of their impact.

Learning Objectives After participating in this educational activity, the psychiatrist should be better able to 1. Identify the characteristic features of suicide reattempters. 2. Evaluate the limitations of the literature. 3. Compare the characteristic features of single attempters and suicide reattempters. The aim of this study is to identify the characteristic features of suicide reattempters. The recognition of the suicide reattempters population as a distinct clinical population may encourage future preventive and clinical work with this high-risk subgroup and thus reduce deaths. A systematic literature review was carried out in order to identify the key demographic, psychological, and clinical variables associated with the repetition of suicide attempts. In addition, we wished to analyze the operational definitions of the repetition of suicide attempts proposed in the scientific literature. Studies published from 2000 to 2012 were identified in PubMed, PsycINFO, and Web of Science databases and were selected according to predetermined criteria. We examined a total of 1480 articles and selected 86 that matched our search criteria. The literature is heterogeneous, with no consensus regarding the operational definitions of suicide reattempters. Comparison groups in the literature have also been inconsistent and include subjects making a single lifetime attempt and subjects who did not reattempt during a defined study period. Suicide reattempters were associated with higher rates of the following characteristics: unemployment, unmarried status, diagnosis of mental disorders, suicidal ideation, stressful life events, and family history of suicidal behavior. Additional research is needed to establish adequate differentiation and effective treatment plans for this population.

AIMS: The aim of the present study was to identify characteristics in women diagnosed with gestational diabetes mellitus (GDM) that could be predictive of congenital malformations in their infants. METHODS: Using data from the Spanish Collaborative Study of Congenital Malformations (ECEMC), a hospital-based case-control study and surveillance system, we assessed the relationship between a number of maternal variables, including pre-gestational body mass index (BMI), and specific congenital malformations in their infants. RESULTS: The overall risk for a selected group of congenital malformations in an infant of an obese mother with GDM compared with an obese mother with normal glucose tolerance (NGT) was 2.78 (1.38-5.55, P < 0.001). Within the group of mothers with GDM, obesity (BMI > or = 30 kg/m2) was associated with a significantly increased risk of cardiovascular defects compared with non-obese women [OR = 2.82 (1.31-7.04), P < 0.01]. In mothers with NGT, pre-gestational BMI was not associated with congenital malformations. CONCLUSION: Pre-gestational obesity is a predictive variable for congenital malformations in infants of mothers with GDM. The greater their BMI, the higher the risk for congenital malformations in their offspring. Given the blastogenic origin of the congenital defects identified, and the relationship between obesity and Type 2 diabetes, it is probable that this increased risk is as a result of previously unidentified pre-gestational diabetes mellitus (PGD). It is important that overweight and obese women planning a pregnancy be evaluated for the presence of diabetes.

BACKGROUND: In hematology there has recently been increasing interest in inorganic polyphosphate. This polymer accumulates in platelet granules and its functions include modulating various stages of blood coagulation, inducing angiogenesis, and provoking apoptosis of plasma cells. In this study we evaluated the characteristics of intracellular polyphosphate in myeloma cell lines, in primary myeloma cells from patients, and in other human B-cell populations from healthy donors. DESIGN AND METHODS: We have developed a novel flow cytometric method for detecting levels of polyphosphate in cell populations. We also used confocal microscopy and enzymatic analysis to study polyphosphate localization and characteristics. RESULTS: We found that myeloma plasma cells contain higher levels of intracellular polyphosphate than normal plasma cells and other B-cell populations. Localization experiments indicated that high levels of polyphosphate accumulate in the nucleolus of myeloma cells. As the principal function of the nucleolus involves transcription of ribosomal DNA genes, we found changes in the cellular distribution of polyphosphate after the inhibition of nucleolar transcription. In addition, we found that RNA polymerase I activity, responsible for transcription in the nucleolus, is also modulated by polyphosphate, in a dose-dependent manner. CONCLUSIONS: Our results show an unusually high accumulation of polyphosphate in the nucleoli of myeloma cells and a functional relationship of this polymer with nucleolar transcription.

BACKGROUND: Genome reduction is a common evolutionary process in symbiotic and pathogenic bacteria. This process has been extensively characterized in bacterial endosymbionts of insects, where primary mutualistic bacteria represent the most extreme cases of genome reduction consequence of a massive process of gene inactivation and loss during their evolution from free-living ancestors. Sodalis glossinidius, the secondary endosymbiont of tsetse flies, contains one of the few complete genomes of bacteria at the very beginning of the symbiotic association, allowing to evaluate the relative impact of mobile genetic element proliferation and gene inactivation over the structure and functional capabilities of this bacterial endosymbiont during the transition to a host dependent lifestyle. RESULTS: A detailed characterization of mobile genetic elements and pseudogenes reveals a massive presence of different types of prophage elements together with five different families of IS elements that have proliferated across the genome of Sodalis glossinidius at different levels. In addition, a detailed survey of intergenic regions allowed the characterization of 1501 pseudogenes, a much higher number than the 972 pseudogenes described in the original annotation. Pseudogene structure reveals a minor impact of mobile genetic element proliferation in the process of gene inactivation, with most of pseudogenes originated by multiple frameshift mutations and premature stop codons. The comparison of metabolic profiles of Sodalis glossinidius and tsetse fly primary endosymbiont Wiglesworthia glossinidia based on their whole gene and pseudogene repertoires revealed a novel case of pathway inactivation, the arginine biosynthesis, in Sodalis glossinidius together with a possible case of metabolic complementation with Wigglesworthia glossinidia for thiamine biosynthesis. CONCLUSIONS: The complete re-analysis of the genome sequence of Sodalis glossinidius reveals novel insights in the evolutionary transition from a free-living ancestor to a host-dependent lifestyle, with a massive proliferation of mobile genetic elements mainly of phage origin although with minor impact in the process of gene inactivation that is taking place in this bacterial genome. The metabolic analysis of the whole endosymbiotic consortia of tsetse flies have revealed a possible phenomenon of metabolic complementation between primary and secondary endosymbionts that can contribute to explain the co-existence of both bacterial endosymbionts in the context of the tsetse host.