529 research outputs found
Photorespiratory 2-phosphoglycolate metabolism and photoreduction of O2 cooperate in high-light acclimation of Synechocystis sp. strain PCC 6803
In cyanobacteria, photorespiratory 2-phosphoglycolate (2PG) metabolism is mediated by three different routes, including one route involving the glycine decarboxylase complex (Gcv). It has been suggested that, in addition to conversion of 2PG into non-toxic intermediates, this pathway is important for acclimation to high-light. The photoreduction of O2 (Mehler reaction), which is mediated by two flavoproteins Flv1 and Flv3 in cyanobacteria, dissipates excess reductants under high-light by the four electron-reduction of oxygen to water. Single and double mutants defective in these processes were constructed to investigate the relation between photorespiratory 2PG-metabolism and the photoreduction of O2 in the cyanobacterium Synechocystis sp. PCC 6803. The single mutants Δflv1, Δflv3, and ΔgcvT, as well as the double mutant Δflv1/ΔgcvT, were completely segregated but not the double mutant Δflv3/ΔgcvT, suggesting that the T-protein subunit of the Gcv (GcvT) and Flv3 proteins cooperate in an essential process. This assumption is supported by the following results: (1) The mutant Δflv3/ΔgcvT showed a considerable longer lag phase and sometimes bleached after shifts from slow (low light, air CO2) to rapid (standard light, 5% CO2) growing conditions. (2) Photoinhibition experiments indicated a decreased ability of the mutant Δflv3/ΔgcvT to cope with high-light. (3) Fluorescence measurements showed that the photosynthetic electron chain is reduced in this mutant. Our data suggest that the photorespiratory 2PG-metabolism and the photoreduction of O2, particularly that catalyzed by Flv3, cooperate during acclimation to high-light stress in cyanobacteria
Incidence of capillary leak syndrome as an adverse effect of drugs in cancer patients: A systematic review and meta-analysis
Capillary leak syndrome (CLS) is a rare disease with profound vascular leakage, which can be associated with a high mortality. There have been several reports on CLS as an adverse effect of anti-cancer agents and therapy, but the incidence of CLS according to the kinds of anti-cancer drugs has not been systemically evaluated. Thus, the aim of our study was to comprehensively meta-analyze the incidence of CLS by different types of cancer treatment or after bone marrow transplantation (BMT). We searched the literatures (inception to July 2018) and among 4612 articles, 62 clinical trials (studies) were eligible. We extracted the number of patients with CLS, total cancer patients, name of therapeutic agent and dose, and type of cancer. We performed a meta-analysis to estimate the summary effects with 95% confidence interval and between-study heterogeneity. The reported incidence of CLS was categorized by causative drugs and BMT. The largest number of studies reported on CLS incidence during interleukin-2 (IL-2) treatment (n = 18), which yielded a pooled incidence of 34.7% by overall estimation and 43.9% by meta-analysis. The second largest number of studies reported on anti-cluster of differentiation (anti-CD) agents (n = 13) (incidence of 33.9% by overall estimation and 35.6% by meta-analysis) or undergoing BMT (n = 7 (21.1% by overall estimation and 21.7% by meta-analysis). Also, anti-cancer agents, including IL-2 + imatinib mesylate (three studies) and anti-CD22 monoclinal antibodies (mAb) (four studies), showed a dose-dependent increase in the incidence of CLS. Our study is the first to provide an informative overview on the incidence rate of reported CLS patients as an adverse event of anti-cancer treatment. This meta-analysis can lead to a better understanding of CLS and assist physicians in identifying the presence of CLS early in the disease course to improve the outcome and optimize management
The Influence of pCO2 and Temperature on Gene Expression of Carbon and Nitrogen Pathways in Trichodesmium IMS101
Growth, protein amount, and activity levels of metabolic pathways in Trichodesmium are influenced by environmental changes such as elevated pCO2 and temperature. This study examines changes in the expression of essential metabolic genes in Trichodesmium grown under a matrix of pCO2 (400 and 900 µatm) and temperature (25 and 31°C). Using RT-qPCR, we studied 21 genes related to four metabolic functional groups: CO2 concentrating mechanism (bicA1, bicA2, ccmM, ccmK2, ccmK3, ndhF4, ndhD4, ndhL, chpX), energy metabolism (atpB, sod, prx, glcD), nitrogen metabolism (glnA, hetR, nifH), and inorganic carbon fixation and photosynthesis (rbcL, rca, psaB, psaC, psbA). nifH and most photosynthetic genes exhibited relatively high abundance and their expression was influenced by both environmental parameters. A two to three orders of magnitude increase was observed for glnA and hetR only when both pCO2 and temperature were elevated. CO2 concentrating mechanism genes were not affected by pCO2 and temperature and their expression levels were markedly lower than that of the nitrogen metabolism and photosynthetic genes. Many of the CO2 concentrating mechanism genes were co-expressed throughout the day. Our results demonstrate that in Trichodesmium, CO2 concentrating mechanism genes are constitutively expressed. Co-expression of genes from different functional groups were frequently observed during the first half of the photoperiod when oxygenic photosynthesis and N2 fixation take place, pointing at the tight and complex regulation of gene expression in Trichodesmium. Here we provide new data linking environmental changes of pCO2 and temperature to gene expression in Trichodesmium. Although gene expression indicates an active metabolic pathway, there is often an uncoupling between transcription and enzyme activity, such that transcript level cannot usually be directly extrapolated to metabolic activity
Acceptability and efficacy of intra-rectal quinine alkaloids as a pre-transfer treatment of non-per os malaria in peripheral health care facilities in Mopti, Mali
<p>Abstract</p> <p>Background</p> <p>The acceptability and efficacy of a new kit with a new formulation of quinine alkaloids designed for the intra-rectal administration in the treatment of non-per os malaria was assessed in the peripheral health care system of Mopti, Mali.</p> <p>Methods</p> <p>A single-arm trial was conducted from August 2003 to January 2004. An initial dose of diluted quinine alkaloids (20 mg/kg Quinimax<sup>®</sup>) was administered by the intra-rectal route to children with presumptive non per-os malaria at six peripheral heath care centres. The children were then referred to two referral hospitals where standard inpatient care including intravenous route were routinely provided. A malaria thick smear was done at inclusion and a second malaria thick smear after arrival at the referral facility, where a more complete clinical examination and laboratory testing was done to confirm diagnosis. Confirmed cases of severe malaria or others diseases were treated according to national treatment guidelines. Cases of non per-os malaria received a second dose of intra rectal quinine alkaloids. Primary outcome was acceptability of the intra rectal route by children and their parents as well as the ease to handle the kit by health care workers.</p> <p>Results</p> <p>The study included 134 children with a median age of 33 months and 53.7% were male. Most of the children (67%) and 92% of parents or guardians readily accepted the intra-rectal route; 84% of health care workers found the kit easy to use. At the peripheral health care centres, 32% of children had a coma score ≤ 3 and this was reduced to 10% at the referral hospital, following one dose of intra-rectal quinine alkaloids (IRQA). The mean time to availability of oral route treatment was 1.8 ± 1.1 days. Overall, 73% of cases were confirmed severe malaria and for those the case fatality rate was 7.2%.</p> <p>Conclusion</p> <p>IRQA was well accepted by children, their parents/guardians and by the health workers at peripheral health facilities in Mopti, Mali. There was also a quick recovery from deep coma and a reduced case fatality rate in severe malaria.</p
Height and timing of growth spurt during puberty in young people living with vertically acquired HIV in Europe and Thailand.
OBJECTIVE: The aim of this study was to describe growth during puberty in young people with vertically acquired HIV. DESIGN: Pooled data from 12 paediatric HIV cohorts in Europe and Thailand. METHODS: One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1-10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters. RESULTS: At ART initiation, median age and HAZ was 6.4 [interquartile range (IQR): 2.8, 9.0] years and -1.2 (IQR: -2.3 to -0.2), respectively. Median follow-up was 9.1 (IQR: 6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20-0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21-1.78) years later in those starting with HAZ less than -3 compared with HAZ at least -1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than -1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least -1, there was no association with age. Girls and boys who initiated ART with HAZ at least -1 maintained a similar height to the WHO reference mean. CONCLUSION: Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least -1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age
Artemisinin derivatives versus quinine in treating severe malaria in children: a systematic review
<p>Abstract</p> <p>Background</p> <p>The efficacy of intravenous quinine, which is the mainstay for treating severe malaria in children, is decreasing in South East Asia and Africa. Artemisinin derivatives are a potential alternative to quinine. However, their efficacy compared to quinine in treating severe malaria in children is not clearly understood. The objective of this review was to assess the efficacy of parenteral artemisinin derivatives versus parenteral quinine in treating severe malaria in children.</p> <p>Methods</p> <p>All randomized controlled studies comparing parenteral artemisinin derivatives with parenteral quinine in treating severe malaria in children were included in the review. Data bases searched were: The Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 4, 2007), MEDLINE (1966 to February 2008), EMBASE (1980 to February 2008), and LILACS (1982 to February 2008). Dichotomous variables were compared using risk ratios (RR) and the continuous data using weighted mean difference (WMD).</p> <p>Results</p> <p>Twelve trials were included (1,524 subjects). There was no difference in mortality between artemisinin derivatives and quinine (RR = 0.90, 95% CI 0.73 to 1.12). The artemisinin derivatives resolved coma faster than quinine (WMD = -4.61, 95% CI: -7.21 to -2.00, fixed effect model), but when trials with adequate concealment only were considered this differences disappeared. There was no statistically significant difference between the two groups in parasite clearance time, fever clearance time, incidence of neurological sequelae and 28<sup>th </sup>day cure rate. One trial reported significantly more local reactions at the injection site with intramuscular quinine compared to artemether. None of the trials was adequately powered to demonstrate equivalence.</p> <p>Conclusion</p> <p>There was no evidence that treatment of children with severe malaria with parenteral artemisinin derivatives was associated with lower mortality or long-term morbidity compared to parenteral quinine. Future studies require adequately powered equivalence trial design to decide whether both drugs are equally effective.</p
Priming with recombinant auxotrophic BCG expressing HIV-1 Gag, RT and Gp120 and boosting with recombinant MVA induces a robust T cell response in mice
In previous studies we have shown that a pantothenate auxotroph of Myocbacterium bovis BCG (BCGΔ panCD ) expressing HIV-1 subtype C Gag induced Gag-specific immune responses in mice and Chacma baboons after prime-boost immunization in combination with matched rMVA and VLP vaccines respectively. In this study recombinant BCG (rBCG) expressing HIV-1 subtype C reverse transcriptase and a truncated envelope were constructed using both the wild type BCG Pasteur strain as a vector and the pantothenate auxotroph. Mice were primed with rBCG expressing Gag and RT and boosted with a recombinant MVA, expressing a polyprotein of Gag, RT, Tat and Nef (SAAVI MVA-C). Priming with rBCGΔ panCD expressing Gag or RT rather than the wild type rBCG expressing Gag or RT resulted in higher frequencies of total HIV-specific CD8 + T cells and increased numbers of T cells specific to the subdominant Gag and RT epitopes. Increasing the dose of rBCG from 10 5 cfu to 10 7 cfu also led to an increase in the frequency of responses to subdominant HIV epitopes. A mix of the individual rBCGΔ panCD vaccines expressing either Gag, RT or the truncated Env primed the immune system for a boost with SAAVI MVA-C and generated five-fold higher numbers of HIV-specific IFN-γ-spot forming cells than mice primed with rBCGΔ panCD containing an empty vector control. Priming with the individual rBCGΔ panCD vaccines or the mix and boosting with SAAVI MVA-C also resulted in the generation of HIV-specific CD4 + and CD8 + T cells producing IFN-γ and TNF-α and CD4 + cells producing IL-2. The rBCG vaccines tested in this study were able to prime the immune system for a boost with rMVA expressing matching antigens, inducing robust, HIV-specific T cell responses to both dominant and subdominant epitopes in the individual proteins when used as individual vaccines or in a mix
An Evaluation of the Fe-N Phase Diagram Considering Long-Range Order of N Atoms in γ'-Fe4N1-x and ε-Fe2N1-z
The chemical potential of nitrogen was described as a function of nitrogen content for the Fe-N phases α-Fe[N], γ'-Fe4N1-x, and ε-Fe2N1-z. For α-Fe[N], an ideal, random distribution of the nitrogen atoms over the octahedral interstices of the bcc iron lattice was assumed; for γ'-Fe4N1-x and ε-Fe2N1-z, the occurrence of a long-range ordered distribution of the nitrogen atoms over the octahedral interstices of the close packed iron sublattices (fcc and hcp, respectively) was taken into account. The theoretical expressions were fitted to nitrogen-absorption isotherm data for the three Fe-N phases. The α/α + γ', α + γ'/γ', γ'/γ' + ε, and γ' + ε/ε phase boundaries in the Fe-N phase diagram were calculated from combining the quantitative descriptions for the absorption isotherms with the known composition of NH3/H2 gas mixtures in equilibrium with coexisting α and γ' phases and in equilibrium with coexisting γ' and ε phases. Comparison of the present phase boundaries with experimental data and previously calculated phase boundaries showed a major improvement as compared to the previously calculated Fe-N phase diagrams, where long-range order for the nitrogen atoms in the γ' and ε phases was not accounted for
Infection control, genetic assessment of drug resistance and drug susceptibility testing in the current management of multidrug/extensively-resistant tuberculosis (M/XDR-TB) in Europe: A tuberculosis network European Trialsgroup (TBNET) study
Aim Europe has the highest documented caseload and greatest increase in multidrug and extensively drug-resistant tuberculosis (M/XDR-TB) of all World Health Organization (WHO) regions. This survey examines how recommendations for M/XDR-TB management are being implemented. Methods TBNET is a pan-European clinical research collaboration for tuberculosis. An email survey of TBNET members collected data in relation to infection control, access to molecular tests and basic microbiology with drug sensitivity testing. Results 68/105 responses gave valid information and were from countries within the WHO European Region. Inpatient beds matched demand, but single rooms with negative pressure were only available in low incidence countries; ultraviolet decontamination was used in 5 sites, all with >10 patients with M/XDR-TB per year. Molecular tests for mutations associated with rifampicin resistance were widely available (88%), even in lower income and especially in high incidence countries. Molecular tests for other first line and second line drugs were less accessible (76 and 52% respectively). A third of physicians considered that drug susceptibility results were delayed by > 2 months. Conclusion Infection control for inpatients with M/XDR-TB remains a problem in high incidence countries. Rifampicin resistance is readily detected, but tests to plan regimens tailored to the drug susceptibilities of the strain of Mycobacterium tuberculosis are significantly delayed, allowing for further drug resistance to develop
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