The Evolutionary Ebb and Flow of Genomic Nucleotide Content

Nucleotide content is one of the most obvious and most easily quantifiable features of a genome. Consequently, all reports of new genome sequences include a report on the nucleotide content, i.e., the frequencies of each of the four nucleotide bases in the genome sequence. Despite the ease with which nucleotide content can be measured, however, it has proved to be much more complicated to explain the evolution of the genomic nucleotide content. A number of different explanations have been proposed. These include the effects of biased mutational patterns (i.e. neutralist models) such as biased DNA repair during recombination, as well as the effect of natural selection on shaping the genomic nucleotide content (i.e. selectionist models). A well known example for the latter group of theories is the effect of temperature in selecting for higher GC content to enhance the thermostability of the DNA. However, many of these theories do not address the problem of variations in nucleotide content between different regions of a single genome, i.e., intragenomic compositional heterogeneity. In this study, I investigate the evolutionary behaviour of the genomic nucleotide content in a group of model organisms and show that the current state of the nucleotide content of a genome by itself cannot always explain the entire evolutionary history of that genome and, in fact, the sequence of events happening to a genome regarding its nucleotide content can be much more complicated than how it looks. For example I show that having an unbiased content doesn’t necessary mean a stationary nucleotide substitution model in an organism. In this study I show that the bias in nucleotide content of a genome can change its direction several times and this going back and forth can actually happen very fast; fast enough to trace the results of this ebb and flow within the same genus. I present an example of this evolutionary ebb and flow of genomic nucleotide content within genus Plasmodium. I also discuss that these exceptional behaviours of the nucleotide contents of the genomes can, indeed, affect other features of living organisms such as the substitution rates between different nucleotides as well as their protein content, and consequently they can interfere with phylogenetic studies. In order to explain the heterogeneities within a single genome, I investigate the relationship between gene length and the degree of nucleotide bias, and find that these two parameters show a significant negative correlation. This lead me to propose a mechanism that can explain heterogeneity in the nucleotide content of the genome, without having to invoke variations in mutational patterns between different parts of the same genome. My proposed model resembles Charlesworth’s “Background Selection” model. My findings shed light on the importance of the evolutionary behaviour of the genomic nucleotide content to be considered in studying different features of an organism as well as studying the evolutionary relationship between the organism of our interest and other related species

Nurses’ strategies in prevention of nursing error recurrence in chronic critical care: A qualitative study

oai:ojs.cdjournal.muk.ac.ir:article/74BACKGROUND: Nursing errors are common in critical care units while most of them are preventable. Critical care nurses are uniquely positioned to prevent the recurrence of nursing errors. The purpose of this study was to explore the strategies considered or used by nurses in order to prevent the recurrence of nursing errors in chronic critical care units. METHODS: A qualitative design using content analysis method was employed in the present study. In-depth interviews were conducted with a sample of 17 participants, recruited through purposive sampling. This study was conducted in 2011-2012 in Iran. RESULTS: Results indicated that the strategies used by critical care nurses to prevent recurrence of nursing errors include personal strategies (paying more attention, updating information, reminding and hinting, experience sharing, prevention), and expectations from the organization (increasing intrinsic motivation and decreasing work pressure). CONCLUSION: Nursing administrators must be aware of the individual strategies used by the nurses to develop and promote their implementation and underlying these strategies. Identifying and understanding the strategies used by nurses can help them in their support provision. Explored strategies can be used to develop interventions for prevention of nursing errors. Further exploration of the question of how the nursing context will influence strategy selection and why is necessary. Regarding the strategies used by nurses, nurse managers must utilize them in planning in order to develop an error free care.

A Review of the Factors Associated with Marital Satisfaction

Marital satisfaction is one of the common concepts used for assessing happiness and stability in a marriage. It is a multidimensional concept that is affected by several factors. The aim of this study was to review factors influencing marital satisfaction or dissatisfaction. A search through academic electronic databases, including PubMed, ScienceDirect, MEDLINE (Medical Literature Analysis and Retrieval System Online), Scopus, Wiley Online Library, Cochrane Library, Google Scholar, and Iranian databases in the period from 2000 to 2015, yielded 250 scientific papers. Related keywords that were used included marital satisfaction, marriage satisfaction, marital adjustment, and couple satisfaction. After reading the titles, 80 papers that satisfied the criteria for inclusion were selected. In general, 80 papers that were eligible to enter the study were reviewed. Following the review of papers, factors deemed to have considerable influence on marital satisfaction were identified as follows: demographic specifications, personality attributes, attachment style, relationship, communication and intimacy, couples’ families, forgiveness and sacrifice, religion, emotional intelligence, personal health, and sexual relations (sex). Family counselors and therapists can benefit from these results to obtain a deeper perception of the foundations of married life and eventually, to help decrease the high divorce rate. Thus, conducting research on marital satisfaction to provide evidence for effecting a management strategy as well as to provide recommendation is indispensabl

Nurses’ strategies in prevention of nursing error recurrence in chronic critical care: A qualitative study

BACKGROUND: Nursing errors are common in critical care units while most of them are preventable. Critical care nurses are uniquely positioned to prevent the recurrence of nursing errors. The purpose of this study was to explore the strategies considered or used by nurses in order to prevent the recurrence of nursing errors in chronic critical care units. METHODS: A qualitative design using content analysis method was employed in the present study. In-depth interviews were conducted with a sample of 17 participants, recruited through purposive sampling. This study was conducted in 2011-2012 in Iran. RESULTS: Results indicated that the strategies used by critical care nurses to prevent recurrence of nursing errors include personal strategies (paying more attention, updating information, reminding and hinting, experience sharing, prevention), and expectations from the organization (increasing intrinsic motivation and decreasing work pressure). CONCLUSION: Nursing administrators must be aware of the individual strategies used by the nurses to develop and promote their implementation and underlying these strategies. Identifying and understanding the strategies used by nurses can help them in their support provision. Explored strategies can be used to develop interventions for prevention of nursing errors. Further exploration of the question of how the nursing context will influence strategy selection and why is necessary. Regarding the strategies used by nurses, nurse managers must utilize them in planning in order to develop an error free care

Spatial and temporal homogeneity of driver mutations in diffuse intrinsic pontine glioma.

Diffuse Intrinsic Pontine Gliomas (DIPGs) are deadly paediatric brain tumours where needle biopsies help guide diagnosis and targeted therapies. To address spatial heterogeneity, here we analyse 134 specimens from various neuroanatomical structures of whole autopsy brains from nine DIPG patients. Evolutionary reconstruction indicates histone 3 (H3) K27M-including H3.2K27M-mutations potentially arise first and are invariably associated with specific, high-fidelity obligate partners throughout the tumour and its spread, from diagnosis to end-stage disease, suggesting mutual need for tumorigenesis. These H3K27M ubiquitously-associated mutations involve alterations in TP53 cell-cycle (TP53/PPM1D) or specific growth factor pathways (ACVR1/PIK3R1). Later oncogenic alterations arise in sub-clones and often affect the PI3K pathway. Our findings are consistent with early tumour spread outside the brainstem including the cerebrum. The spatial and temporal homogeneity of main driver mutations in DIPG implies they will be captured by limited biopsies and emphasizes the need to develop therapies specifically targeting obligate oncohistone partnerships

Barriers to support nurses as second victim of medical errors: A qualitative study

BackgroundGiven the inevitability of medical errors and their impact on health workers, providing support to those who suffer is vital for their physical and mental recovery. Identifying the barriers to obtaining support is imperative in this regard.AimsThe current study was conducted to identify the barriers regarding supporting nurses as second victims of nursing errors in clinical settings in Iran.MethodsThis qualitative study was conducted with a sample, which was included 18 nurses. The subjects were selected through the purposive sampling method, and data were collected using in-depth and semi-structured interviews. The data were analysed using methods as described by Graneheim and Lundman (citation needed). The research context included the general and specialized departments of hospitals in Tehran, Iran, during 2017.ResultsAccording to the results, mismanagement, Cultural barriers, inadequate information, and Legal barriers were the main barriers to supporting nurses.ConclusionTraining nurses about the second victim phenomenon is recommended as well as the methods to manage the effects of this phenomenon, the supportive resources, and legal issues

The survival rate of hepatocellular carcinoma in Asian countries

Hepatocellular carcinoma or Liver cancer (LC) is the sixth most common cancer and the fourth cause of death worldwide in 2018. There has not been a comprehensive study on the survival rate of patients with LC in Asia yet. Therefore, the present study was conducted to evaluate the survival rate of patients with LC in Asian countries. The methodology of the present study is based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement. The researchers searched five international databases including Medline/PubMed, Scopus, Embase, Web of Knowledge and ProQuest until July 1, 2018. We also searched Google Scholar for detecting grey literature. The Newcastle-Ottawa Quality Assessment Form was used to evaluate the quality of selected papers. A total of 1425 titles were retrieved. 63 studies met the inclusion criteria. Based on the random-effect model one-year, three-year and five-year survival rate of LC were 34.8 % (95 % CI; 30.3-39.3), 19 % (95 % CI ; 18.2-21.8) and 18.1 % (95 % CI ;16.1-20.1) respectively. According to the results of our study, the LC survival rate in Asian countries is relatively lower than in Europe and North America

Isolated hepatitis B core antibody in HIV infected patients--can response to hepatitis B vaccine help to elucidate the cause?

Background: Concomitant hepatitis B and HIV infections are common. In some of these patients, HBcAb is the only serologic marker of hepatitis B. This study was conducted to elucidate the cause of isolated HBcAb in HIV-infected patients via hepatitis B vaccination. Methods: In this interventional study during 2014-15 in the HIV Clinic in Hamadan, thirty four patients with HIV infection and isolated HBcAb positive isolate, received hepatitis B vaccine and their responses to vaccination were investigated. Demographic data, stage of disease, and status of CD4 and HCV Ab were extracted from the patients' medical records and were entered in a checklist. Results: Of the 103 HIV positive patients, the prevalence of HBs Ag, and HBc Ab isolates were 6.79% (n=7) and 46.6% (n=48), respectively. All of the patients with isolated HBcAb were positive for HCV Ab. Among the 48 patients with isolated HBc Ab, 34 (70.8%) were available and examined for HBV DNA in serum samples. The result of PCR was negative in all. After the first round of hepatitis B vaccination, HBs Ab titer exceeded 10 International Units Per Liter (IU/L) in 58.8% of patients with isolated HBc Ab. With the completion of the three-dose of vaccine, this titer was observed in 97% of patients. Significant correlation was observed between titer of antibodies and values of CD4 cells. Conclusions: Due to favorable response to hepatitis B vaccination in HIV positive patients with isolated HBc Ab, false positive HBc Ab and recovery from previous infection were more probable than hidden hepatitis B

Integrated Molecular Meta-Analysis of 1,000 Pediatric High-Grade and Diffuse Intrinsic Pontine Glioma.

We collated data from 157 unpublished cases of pediatric high-grade glioma and diffuse intrinsic pontine glioma and 20 publicly available datasets in an integrated analysis of >1,000 cases. We identified co-segregating mutations in histone-mutant subgroups including loss of FBXW7 in H3.3G34R/V, TOP3A rearrangements in H3.3K27M, and BCOR mutations in H3.1K27M. Histone wild-type subgroups are refined by the presence of key oncogenic events or methylation profiles more closely resembling lower-grade tumors. Genomic aberrations increase with age, highlighting the infant population as biologically and clinically distinct. Uncommon pathway dysregulation is seen in small subsets of tumors, further defining the molecular diversity of the disease, opening up avenues for biological study and providing a basis for functionally defined future treatment stratification