285 research outputs found

    Drosophila melanogaster γ-TuRC is dispensable for targeting γ-tubulin to the centrosome and microtubule nucleation

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    In metazoans, γ-tubulin acts within two main complexes, γ-tubulin small complexes (γ-TuSCs) and γ-tubulin ring complexes (γ-TuRCs). In higher eukaryotes, it is assumed that microtubule nucleation at the centrosome depends on γ-TuRCs, but the role of γ-TuRC components remains undefined

    Sporadic and genetic forms of paediatric somatotropinoma: a retrospective analysis of seven cases and a review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Somatotropinoma, a pituitary adenoma characterised by excessive production of growth hormone (GH), is extremely rare in childhood. A genetic defect is evident in some cases; known genetic changes include: multiple endocrine neoplasia type 1 (MEN1<it>)</it>; Carney complex; McCune-Albright syndrome; and, more recently identified, aryl hydrocarbon receptor-interacting protein (AIP). We describe seven children with somatotropinoma with a special focus on the differences between genetic and sporadic forms.</p> <p>Methods</p> <p>Seven children who presented in our regional network between 1992 and 2008 were included in this retrospective analysis. First-type therapy was somatostatin (SMS) analogues or transsphenoidal surgery. Control was defined as when insulin-like growth factor-1 (IGF-1) levels were within the normal range for the patient's age at 6 months after therapy, associated with decreasing tumour volume.</p> <p>Results</p> <p>Patients were aged 5-17 years and the majority (n = 6) were male. Four patients had an identified genetic mutation (McCune-Albright syndrome: n = 1; MEN1: n = 1; AIP: n = 2); the remaining three cases were sporadic. Accelerated growth rate was reported as the first clinical sign in four patients. Five patients presented with macroadenoma; invasion was noted in four of them (sporadic: n = 1; genetic: n = 3). Six patients were treated with SMS analogues; normalisation of IGF-1 occurred in one patient who had a sporadic intrasellar macroadenoma. Multiple types of therapy were necessary in all patients with an identified genetic mutation (4 types: n = 1; 3 types: n = 2; 2 types: n = 1), whereas two of the three patients with sporadic somatotropinoma required only one type of therapy.</p> <p>Conclusions</p> <p>This is the first series that analyzes the therapeutic response of somatotropinoma in paediatric patients with identified genetic defects. We found that, in children, genetic somatotropinomas are more invasive than sporadic somatotropinomas. Furthermore, SMS analogues appear to be less effective for treating genetic somatotropinoma than sporadic somatotropinoma.</p

    Changes in the atmospheric CH4 gradient between Greenland and Antarctica during the Holocene

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    High-resolution records of atmospheric methane over the last 11,500 years have been obtained from two Antarctic ice cores (D47 and Byrd) and a Greenland core (Greenland Ice Core Project). These cores show similar trapping conditions for trace gases in the ice combined with a comparable sampling resolution; this together with a good relative chronology, provided by unequivocal CH4 features, allows a direct comparison of the synchronized Greenland and Antarctic records, and it reveals significant changes in the interpolar difference of CH4 mixing ratio with time. On the average, over the full Holocene records, we find an interpolar difference of 44±7 ppbv. A minimum difference of 33±7 ppbv is observed from 7 to 5 kyr B.P. whereas the maximum gradient (50±3 ppbv) took place from 5 to 2.5 kyr B.P. A gradient of 44±4 ppbv is observed during the early Holocene (11.5 to 9.5 kyr B.P). We use a three-box model to translate the measured differences into quantitative contributions of methane sources in the tropics and the middle to high latitudes of the northern hemisphere. The model results support the previous interpretation that past natural CH4 sources mainly lay in tropical regions, but it also suggests that boreal regions provided a significant contribution to the CH4 budget especially at the start of the Holocene. The growing extent of peat bogs in boreal regions would also have counterbalanced the drying of the tropics over the second half of the Holocene. Finally, our model results suggest a large source increase in tropical regions from the late Holocene to the last millennium, which may partly be caused by anthropogenic emissions

    Thrombolysis with tissue plasminogen activator in acute myocardial infarction: no additional benefit from immediate percutaneous coronary angioplasty

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    A randomised trial of 367 patients with acute myocardial infarction was performed to determine whether an invasive strategy combining thrombolysis with recombinant tissue-type plasminogen activator (rTPA), heparin, and acetylsalicylic acid, and immediate percutaneous transluminal coronary angioplasty (PTCA) would be superior to a noninvasive strategy with the same medical treatment but without immediate angiography and PTCA. Intravenous infusion of 100 mg rTPA was started within 5 h after onset of symptoms (median 156 min). Angiography was performed 6-165 min later in 180 out of 183 patients allocated to the invasive strategy; 184 patients were allocated to the non-invasive strategy. Immediate PTCA reduced the percentage stenosis of the infarc

    24-Month Clinical, Immuno-Virological Outcomes, and HIV Status Disclosure in Adolescents Living With Perinatally-Acquired HIV in the IeDEA-COHADO Cohort in Togo and Côte d'Ivoire, 2015-2017

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    Background: Adolescents living with perinatally-acquired HIV (APHIV) face challenges including HIV serostatus disclosure. We assessed their 24-month outcomes in relation to the disclosure of their own HIV serostatus. Methods: Nested within the International epidemiologic Database to Evaluate AIDS pediatric West African prospective cohort (IeDEA pWADA), the COHADO cohort included antiretroviral (ART)-treated APHIV aged 10-19 years, enrolled in HIV care before the age of 10 years, in Abidjan (Côte d'Ivoire) and Lomé (Togo) in 2015. We measured the HIV serostatus disclosure at baseline and after 24 months and analyzed its association with a favorable combined 24-month outcome using logistic regression. The 24-month combined clinical immuno-virological outcome was defined as unfavorable when either death, loss to follow-up, progression to WHO-AIDS stage, a decrease of CD4 count >10% compared to baseline, or a detectable viral load (VL > 50 copies/mL) occurred at 24 months. Results: Overall, 209 APHIV were included (51.6% = Abidjan, 54.5% = females). At inclusion, the median CD4 cell count was 521/mm (3) [IQR (281-757)]; 29.6% had a VL measurement, of whom, 3.2% were virologically suppressed. APHIV were younger in Lomé {median age: 12 years [interquartile range (IQR): 11-15]} compared to Abidjan [14 years (IQR: 12-15, p = 0.01)]. Full HIV-disclosure increased from 41.6% at inclusion to 74.1% after 24 months. After 24 months of follow-up, six (2.9%) died, eight (3.8%) were lost to follow-up, and four (1.9%) were transferred out. Overall, 73.7% did not progress to the WHO-AIDS stage, and 62.7% had a CD4 count above (±10%) of the baseline value (48.6% in Abidjan vs. 69.0% in Lomé, p 2 years compared to those who had not been disclosed to [aOR = 0.21, 95% CI (0.05-0.84), p = 0.03]. Conclusions: The frequency of HIV-disclosure improved over time and differed across countries but remained low among West African APHIV. Overall, the 24-month outcomes were poor. Disclosure before the study was a marker of a poor 24-month outcome in Lomé. Context-specific responses are urgently needed to improve adolescent care and reach the UNAIDS 90% target of virological success

    Race-free estimated glomerular filtration rate equation in kidney transplant recipients:development and validation study

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    OBJECTIVE: To compare the performance of a newly developed race-free kidney recipient specific glomerular filtration rate (GFR) equation with the three current main equations for measuring GFR in kidney transplant recipients.DESIGN: Development and validation study SETTING: 17 cohorts in Europe, the United States, and Australia (14 transplant centres, three clinical trials).PARTICIPANTS: 15 489 adults (3622 in development cohort (Necker, Saint Louis, and Toulouse hospitals, France), 11 867 in multiple external validation cohorts) who received kidney transplants between 1 January 2000 and 1 January 2021.MAIN OUTCOME MEASURE: The main outcome measure was GFR, measured according to local practice. Performance of the GFR equations was assessed using P 30 (proportion of estimated GFR (eGFR) within 30% of measured GFR (mGFR)) and correct classification (agreement between eGFR and mGFR according to GFR stages). The race-free equation, based on creatinine level, age, and sex, was developed using additive and multiplicative linear regressions, and its performance was compared with the three current main GFR equations: Modification of Diet in Renal Disease (MDRD) equation, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2009 equation, and race-free CKD-EPI 2021 equation. RESULTS: The study included 15 489 participants, with 50 464 mGFR and eGFR values. The mean GFR was 53.18 mL/min/1.73m 2 (SD 17.23) in the development cohort and 55.90 mL/min/1.73m 2 (19.69) in the external validation cohorts. Among the current GFR equations, the race-free CKD-EPI 2021 equation showed the lowest performance compared with the MDRD and CKD-EPI 2009 equations. When race was included in the kidney recipient specific GFR equation, performance did not increase. The race-free kidney recipient specific GFR equation showed significantly improved performance compared with the race-free CKD-EPI 2021 equation and performed well in the external validation cohorts (P 30 ranging from 73.0% to 91.3%). The race-free kidney recipient specific GFR equation performed well in several subpopulations of kidney transplant recipients stratified by race (P 30 73.0-91.3%), sex (72.7-91.4%), age (70.3-92.0%), body mass index (64.5-100%), donor type (58.5-92.9%), donor age (68.3-94.3%), treatment (78.5-85.2%), creatinine level (72.8-91.3%), GFR measurement method (73.0-91.3%), and timing of GFR measurement post-transplant (72.9-95.5%). An online application was developed that estimates GFR based on recipient's creatinine level, age, and sex (https://transplant-prediction-system.shinyapps.io/eGFR_equation_KTX/). CONCLUSION: A new race-free kidney recipient specific GFR equation was developed and validated using multiple, large, international cohorts of kidney transplant recipients. The equation showed high accuracy and outperformed the race-free CKD-EPI 2021 equation that was developed in individuals with native kidneys.TRIAL REGISTRATION: ClinicalTrials.gov NCT05229939.</p

    A RasGAP SH3 Peptide Aptamer Inhibits RasGAP-Aurora Interaction and Induces Caspase-Independent Tumor Cell Death

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    The Ras GTPase-activating protein RasGAP catalyzes the conversion of active GTP-bound Ras into inactive GDP-bound Ras. However, RasGAP also acts as a positive effector of Ras and exerts an anti-apoptotic activity that is independent of its GAP function and that involves its SH3 (Src homology) domain. We used a combinatorial peptide aptamer approach to select a collection of RasGAP SH3 specific ligands. We mapped the peptide aptamer binding sites by performing yeast two-hybrid mating assays against a panel of RasGAP SH3 mutants. We examined the biological activity of a peptide aptamer targeting a pocket delineated by residues D295/7, L313 and W317. This aptamer shows a caspase-independent cytotoxic activity on tumor cell lines. It disrupts the interaction between RasGAP and Aurora B kinase. This work identifies the above-mentioned pocket as an interesting therapeutic target to pursue and points its cognate peptide aptamer as a promising guide to discover RasGAP small-molecule drug candidates
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