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OBJECTIVE: This study sought to (1) collate the experiences of university students with concussion history and academic stakeholders through interviews and (2) develop concussion management recommendations for institutions of higher learning using a multidisciplinary Delphi procedure. SETTING: Remote semistructured interviews and online surveys. PARTICIPANTS: The first aim of this study included undergraduate university students with concussion history who did not participate in varsity athletics ( n = 21; 57.1% female), as well as academic faculty/staff with experience assisting university students with their postconcussion academic needs ( n = 7; 71.4% female). The second aim enrolled 22 participants (54.5% female) to serve on the Delphi panel including 9 clinicians, 8 researchers, and 5 academic faculty/staff. DESIGN: An exploratory-sequential mixed-methods approach. MAIN MEASURES: Semistructured interviews were conducted to unveil barriers regarding the return-to-learn (RTL) process after concussion, with emergent themes serving as a general framework for the Delphi procedure. Panelists participated in 3 stages of a modified Delphi process beginning with a series of open-ended questions regarding postconcussion management in higher education. The second stage included anonymous ratings of the recommendations, followed by an opportunity to review and/or modify responses based on the group's consensus. RESULTS: The results from the semistructured interviews indicated students felt supported by their instructors; however, academic faculty/staff lacked information on appropriate academic supports and/or pathways to facilitate the RTL process. Of the original 67 statements, 39 achieved consensus (58.2%) upon cessation of the Delphi procedure across 3 main categories: recommendations for discharge documentation (21 statements), guidelines to facilitate a multidisciplinary RTL approach (10 statements), and processes to obtain academic supports for students who require them after concussion (8 statements). CONCLUSIONS: These findings serve as a basis for future policy in higher education to standardize RTL processes for students who may need academic supports following concussion.
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Conmoción Encefálica , Deportes , Humanos , Femenino , Masculino , Universidades , Alta del Paciente , Conmoción Encefálica/diagnóstico , Conmoción Encefálica/terapia , EstudiantesRESUMEN
OBJECTIVES: To systematically review the scientific literature regarding the acute assessment of sport-related concussion (SRC) and provide recommendations for improving the Sport Concussion Assessment Tool (SCAT6). DATA SOURCES: Systematic searches of seven databases from 2001 to 2022 using key words and controlled vocabulary relevant to concussion, sports, SCAT, and acute evaluation. ELIGIBILITY CRITERIA: (1) Original research articles, cohort studies, case-control studies, and case series with a sample of >10; (2) ≥80% SRC; and (3) studies using a screening tool/technology to assess SRC acutely (<7 days), and/or studies containing psychometric/normative data for common tools used to assess SRC. DATA EXTRACTION: Separate reviews were conducted involving six subdomains: Cognition, Balance/Postural Stability, Oculomotor/Cervical/Vestibular, Emerging Technologies, and Neurological Examination/Autonomic Dysfunction. Paediatric/Child studies were included in each subdomain. Risk of Bias and study quality were rated by coauthors using a modified SIGN (Scottish Intercollegiate Guidelines Network) tool. RESULTS: Out of 12 192 articles screened, 612 were included (189 normative data and 423 SRC assessment studies). Of these, 183 focused on cognition, 126 balance/postural stability, 76 oculomotor/cervical/vestibular, 142 emerging technologies, 13 neurological examination/autonomic dysfunction, and 23 paediatric/child SCAT. The SCAT discriminates between concussed and non-concussed athletes within 72 hours of injury with diminishing utility up to 7 days post injury. Ceiling effects were apparent on the 5-word list learning and concentration subtests. More challenging tests, including the 10-word list, were recommended. Test-retest data revealed limitations in temporal stability. Studies primarily originated in North America with scant data on children. CONCLUSION: Support exists for using the SCAT within the acute phase of injury. Maximal utility occurs within the first 72 hours and then diminishes up to 7 days after injury. The SCAT has limited utility as a return to play tool beyond 7 days. Empirical data are limited in pre-adolescents, women, sport type, geographical and culturally diverse populations and para athletes. PROSPERO REGISTRATION NUMBER: CRD42020154787.
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Conmoción Encefálica , Deportes , Niño , Humanos , Adolescente , Adulto , Femenino , Conmoción Encefálica/diagnóstico , Atletas , Estudios de Casos y Controles , CogniciónRESUMEN
BACKGROUND: Visual estimation of blood loss following delivery often under-reports actual bleed volume. To improve accuracy, quantitative blood loss measurement was introduced for all births in the 12 hospitals providing maternity care in Wales. This intervention was incorporated into a quality improvement programme (Obstetric Bleeding Strategy for Wales, OBS Cymru). We report the incidence of postpartum haemorrhage in Wales over a 1-year period using quantitative measurement. METHODS: This prospective, consecutive cohort included all 31,341 women giving birth in Wales in 2017. Standardised training was cascaded to maternity staff in all 12 hospitals in Wales. The training comprised mock-scenarios, a video and team drills. Uptake of quantitative blood loss measurement was audited at each centre. Data on postpartum haemorrhage of > 1000 mL were collected and analysed according to mode of delivery. Data on blood loss for all maternities was from the NHS Wales Informatics Service. RESULTS: Biannual audit data demonstrated an increase in quantitative measurement from 52.1 to 87.8% (P < 0.001). The incidence (95% confidence intervals, CI) of postpartum haemorrhage of > 1000 mL, > 1500 mL and > 2000 mL was 8.6% (8.3 to 8.9), 3.3% (3.1 to 3.5) and 1.3% (1.2 to 1.4), respectively compared to 5%, 2% and 0.8% in the year before OBS Cymru. The incidence (95% CI) of bleeds of > 1000 mL was similar across the 12 hospitals despite widely varied size, staffing levels and case mix, median (25th to 75th centile) 8.6% (7.8-9.6). The incidence of PPH varied with mode of delivery and was mean (95% CI) 4.9% (4.6-5.2) for unassisted vaginal deliveries, 18.4 (17.1-19.8) for instrumental vaginal deliveries, 8.5 (7.7-9.4) for elective caesarean section and 19.8 (18.6-21.0) for non-elective caesarean sections. CONCLUSIONS: Quantitative measurement of blood loss is feasible in all hospitals providing maternity care and is associated with detection of higher rates of postpartum haemorrhage. These results have implications for the definition of abnormal blood loss after childbirth and for management and research of postpartum haemorrhage.
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Hemorragia Posparto/epidemiología , Adulto , Estudios de Cohortes , Parto Obstétrico/estadística & datos numéricos , Femenino , Humanos , Incidencia , Hemorragia Posparto/patología , Embarazo , Estudios Prospectivos , Gales/epidemiologíaRESUMEN
Hypoxia-inducible factor 1α (HIF-1α) is recognized as a prime molecular target for metastatic cancer. However, no specific HIF-1α inhibitor has been approved for clinical use. Here, we demonstrated that in vivo efficacy of echinomycin in solid tumors with HIF-1α overexpression is formulation-dependent. Compared to previously-used Cremophor-formulated echinomycin, which was toxic and ineffective in clinical trials, liposomal-echinomycin provides significantly more inhibition of primary tumor growth and only liposome-formulated echinomycin can eliminate established triple-negative breast cancer (TNBC) metastases, which are the leading cause of death from breast cancer, as available therapies remain minimally effective at this stage. Pharmacodynamic analyses reveal liposomal-echinomycin more potently inhibits HIF-1α transcriptional activity in primary and metastasized TNBC cells in vivo, the latter of which are HIF-1α enriched. The data suggest that nanoliposomal-echinomycin can provide safe and effective therapeutic HIF-1α inhibition and could represent the most potent HIF-1α inhibitor in prospective trials for metastatic cancer.
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Equinomicina/farmacología , Subunidad alfa del Factor 1 Inducible por Hipoxia/antagonistas & inhibidores , Liposomas/farmacología , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Animales , Línea Celular Tumoral , Equinomicina/química , Femenino , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Liposomas/química , Ratones , Metástasis de la Neoplasia , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/patología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
OBJECTIVES: The literature on fluid biomarkers for concussion has primarily focused on comparing athletes with and without a diagnosis of concussion and on examining the relationship between fluid biomarkers and exposure to head trauma. This systematic literature review aims to examine the strength of evidence for fluid biomarkers to be associated with clinically relevant outcomes in sports-related concussion. METHODS: A systematic literature review was conducted using EmBASE, PubMed, and CINAHL. English-language articles that included athletes participating in organized sports and reported the relationship between at least one fluid biomarker and at least one clinical outcome measure, or provided data that could be used to analyze this relationship, were included. RESULTS: Studies of the relationship between fluid biomarkers and clinical outcomes of concussion have yielded small or variable effects. There were significant inconsistencies in methodology including duration of time post-injury of biomarker collection, use of control groups, the number of time points post-injury that biomarkers were collected, and what clinical outcomes were utilized. CONCLUSION: There is currently insufficient evidence to support a relationship between any of the included fluid biomarkers and clinical outcome measures of concussion. Future research including clinical outcome measures and using standardized study design and methodology is necessary.
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Traumatismos en Atletas , Conmoción Encefálica , Deportes , Atletas , Traumatismos en Atletas/complicaciones , Biomarcadores , HumanosRESUMEN
This communication describes the identification and optimization of a series of pan-KDM5 inhibitors derived from compound 1, a hit initially identified against KDM4C. Compound 1 was optimized to afford compound 20, a 10nM inhibitor of KDM5A. Compound 20 is highly selective for the KDM5 enzymes versus other histone lysine demethylases and demonstrates activity in a cellular assay measuring the increase in global histone 3 lysine 4 tri-methylation (H3K4me3). In addition compound 20 has good ADME properties, excellent mouse PK, and is a suitable starting point for further optimization.
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Inhibidores Enzimáticos/farmacología , Proteína 2 de Unión a Retinoblastoma/antagonistas & inhibidores , Animales , Sitios de Unión , Western Blotting , Línea Celular , Descubrimiento de Drogas , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/aislamiento & purificación , Humanos , Concentración 50 Inhibidora , Ratones , Microsomas Hepáticos/enzimología , Modelos Moleculares , RatasRESUMEN
Memory loss after brain injury can be a source of considerable morbidity, but there are presently few therapeutic options for restoring memory function. We have previously demonstrated that burst stimulation of the fornix is able to significantly improve memory in a rodent model of traumatic brain injury. The present study is a preliminary investigation with a small group of cases to explore whether theta burst stimulation of the fornix might improve memory in humans. Four individuals undergoing stereo-electroencephalography evaluation for drug-resistant epilepsy were enrolled. All participants were implanted with an electrode into the proximal fornix and dorsal hippocampal commissure on the language dominant (n = 3) or language non-dominant (n = 1) side, and stimulation of this electrode reliably produced a diffuse evoked potential in the head and body of the ipsilateral hippocampus. Each participant underwent testing of verbal memory (Rey Auditory-Verbal Learning Test), visual-spatial memory (Medical College of Georgia Complex Figure Test), and visual confrontational naming (Boston Naming Test Short Form) once per day over at least two consecutive days using novel test forms each day. For 50% of the trials, the fornix electrode was continuously stimulated using a burst pattern (200 Hz in 100 ms trains, five trains per second, 100 µs, 7 mA) and was compared with sham stimulation. Participants and examiners were blinded to whether stimulation was active or not, and the order of stimulation was randomized. The small sample size precluded use of inferential statistics; therefore, data were analysed using descriptive statistics and graphic analysis. Burst stimulation of the fornix was not perceived by any of the participants but was associated with a robust reversible improvement in immediate and delayed performance on the Medical College of Georgia Complex Figure Test. There were no apparent differences on either Rey Auditory-Verbal Learning Test or Boston Naming Test. There was no apparent relationship between performance and side of stimulation (language dominant or non-dominant). There were no complications. Preliminary evidence in this small sample of patients with drug-resistant epilepsy suggests that theta burst stimulation of the fornix may be associated with improvement in visual-spatial memory.
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Estimulación Encefálica Profunda/métodos , Epilepsia del Lóbulo Temporal , Fórnix/fisiopatología , Memoria Espacial/fisiología , Adulto , Método Doble Ciego , Potenciales Evocados/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Ritmo Teta , Adulto JovenRESUMEN
Acute myeloid leukemia (AML) with fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) has poor outcomes. FLT3-ITD drives constitutive and aberrant FLT3 signaling, activating STAT5 and upregulating the downstream oncogenic serine/threonine kinase Pim-1. FLT3 inhibitors are in clinical use, but with limited and transient efficacy. We previously showed that concurrent treatment with Pim and FLT3 inhibitors increases apoptosis induction in FLT3-ITD-expressing cells through posttranslational downregulation of Mcl-1. Here we further elucidate the mechanism of action of this dual targeting strategy. Cytotoxicity, apoptosis and protein expression and turnover were measured in FLT3-ITD-expressing cell lines and AML patient blasts treated with the FLT3 inhibitor gilteritinib and/or the Pim inhibitors AZD1208 or TP-3654. Pim inhibitor and gilteritinib cotreatment increased apoptosis induction, produced synergistic cytotoxicity, downregulated c-Myc protein expression, earlier than Mcl-1, increased turnover of both proteins, which was rescued by proteasome inhibition, and increased efficacy and prolonged survival in an in vivo model. Gilteritinib and Pim inhibitor cotreatment of Ba/F3-ITD cells infected with T58A c-Myc or S159A Mcl-1 plasmids, preventing phosphorylation at these sites, did not downregulate these proteins, increase their turnover or increase apoptosis induction. Moreover, concurrent treatment with gilteritinib and Pim inhibitors dephosphorylated (activated) the serine/threonine kinase glycogen synthase kinase-3ß (GSK-3ß), and GSK-3ß inhibition prevented c-Myc and Mcl-1 downregulation and decreased apoptosis induction. The data are consistent with c-Myc T58 and Mcl-1 S159 phosphorylation by activated GSK-3ß as the mechanism of action of gilteritinib and Pim inhibitor combination treatment, further supporting GSK-3ß activation as a therapeutic strategy in FLT3-ITD AML. SIGNIFICANCE: FLT3-ITD is present in 25% of in AML, with continued poor outcomes. Combining Pim kinase inhibitors with the FDA-approved FLT3 inhibitor gilteritinib increases cytotoxicity in vitro and in vivo through activation of GSK-3ß, which phosphorylates and posttranslationally downregulates c-Myc and Mcl-1. The data support efficacy of GSK-3ß activation in FLT3-ITD AML, and also support development of a clinical trial combining the Pim inhibitor TP-3654 with gilteritinib.
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Compuestos de Anilina , Leucemia Mieloide Aguda , Pirazinas , Tirosina Quinasa 3 Similar a fms , Humanos , Glucógeno Sintasa Quinasa 3 beta/genética , Tirosina Quinasa 3 Similar a fms/genética , Proteínas Serina-Treonina Quinasas/uso terapéutico , Inhibidores de Proteínas Quinasas/farmacología , Leucemia Mieloide Aguda/tratamiento farmacológico , Serina/metabolismoRESUMEN
BACKGROUND: Sport-related concussions (SRCs) affect millions of adolescents and young adults annually in the USA; however, current SRC consensus statements provide limited guidance on academic support for students within higher education. OBJECTIVE: To generate consensus on appropriate academic recommendations for clinicians, students, and academic stakeholders to support university students during their recovery. METHODS: Panelists participated in three stages of a modified Delphi procedure: the first stage included a series of open-ended questions after reviewing a literature review on post-SRC return-to-learn (RTL) in higher education; the second stage asked panelists to anonymously rate the recommendations developed through the first Delphi stage using a 9-point scale; and the final stage offered panelists the opportunity to change their responses and/or provide feedback based on the group's overall ratings. RESULTS: Twenty-two panelists including clinicians, concussion researchers, and academic stakeholders (54.5% female) from 15 institutions and/or healthcare systems participated in a modified Delphi procedure. A total of 42 statements were developed after round one. Following the next two rounds, 27 statements achieved consensus amongst the panel resulting in the four-stage Post-Concussion Collegiate RTL Protocol. CONCLUSION: There are several unique challenges when assisting university students back to the classroom after SRC. Explicit guidelines on when to seek additional medical care (e.g., if they are experiencing worsening or persistent symptoms) and how to approach their instructor(s) regarding academic support may help the student self-advocate. Findings from the present study address barriers and provide a framework for universities to facilitate a multidisciplinary approach amongst medical and academic stakeholders.
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Traumatismos en Atletas , Conmoción Encefálica , Deportes , Adolescente , Femenino , Humanos , Masculino , Adulto Joven , Traumatismos en Atletas/diagnóstico , Conmoción Encefálica/diagnóstico , Técnica Delphi , UniversidadesRESUMEN
DNA polymerase gamma (pol gamma) is responsible for replication and repair of mitochondrial DNA (mtDNA). Over 150 mutations in POLG (which encodes pol gamma) have been discovered in patients with mitochondrial disorders including Alpers, progressive external ophthalmoplegia and ataxia-neuropathy syndrome. However, the severity and dominance of many POLG disease-associated mutations are unclear, because they have been reported in sporadic cases. To understand the consequences of pol gamma disease-associated mutations in vivo, we identified dominant and recessive changes in mtDNA mutagenesis, depletion and mitochondrial dysfunction caused by 31 mutations in the conserved regions of the gene, MIP1, which encodes the Saccharomyces cerevisiae ortholog of human pol gamma. Twenty mip1 mutant enzymes were shown to disrupt mtDNA replication and may be sufficient to cause disease. Previously uncharacterized sporadic mutations, Q308H, R807C, G1076V, R1096H and S1104C, caused decreased polymerase activity leading to mtDNA depletion and mitochondrial dysfunction. We present evidence showing a limited role of point mutagenesis by these POLG mutations in mitochondrial dysfunction and disease progression. Instead, most mitochondrial defective mip1 mutants displayed reduced or depleted mtDNA. We also determined that the severity of the phenotype of the mip1 mutant strain correlates with the age of onset of disease associated with the human ortholog. Finally, we demonstrated that increasing nucleotide pools by overexpression of ribonucleotide reductase (RNR1) suppressed mtDNA replication defects caused by several dominant mip1 mutations, and the orthologous human mutations revealed severe nucleotide binding defects.
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ADN Polimerasa I/genética , ADN Polimerasa Dirigida por ADN/genética , Enfermedades Mitocondriales/genética , Modelos Moleculares , Fenotipo , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Factores de Edad , ADN Polimerasa gamma , Cartilla de ADN/genética , Replicación del ADN/genética , ADN Mitocondrial/genética , ADN Polimerasa Dirigida por ADN/química , Histidina/química , Humanos , Mutación/genética , Plásmidos/genéticaRESUMEN
A combination of anti-CTLA-4 plus anti-PD-1/PD-L1 is the most effective cancer immunotherapy but causes high incidence of immune-related adverse events (irAEs). Here we report that targeting of HIF-1α suppressed PD-L1 expression on tumor cells and tumor-infiltrating myeloid cells, but unexpectedly induced PD-L1 in normal tissues by an IFN-γ-dependent mechanism. Targeting the HIF-1α/PD-L1 axis in tumor cells reactivated tumor-infiltrating lymphocytes and caused tumor rejection. The HIF-1α inhibitor echinomycin potentiated the cancer immunotherapeutic effects of anti-CTLA-4 therapy, with efficacy comparable to that of anti-CTLA-4 plus anti-PD-1 antibodies. However, while anti-PD-1 exacerbated irAEs triggered by ipilimumab, echinomycin protected mice against irAEs by increasing PD-L1 levels in normal tissues. Our data suggest that targeting HIF-1α fortifies the immune tolerance function of the PD-1/PD-L1 checkpoint in normal tissues but abrogates its immune evasion function in the tumor microenvironment to achieve safer and more effective immunotherapy.
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Equinomicina , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Neoplasias , Animales , Antígeno B7-H1 , Equinomicina/farmacología , Evasión Inmune , Tolerancia Inmunológica , Linfocitos Infiltrantes de Tumor , Ratones , Neoplasias/terapia , Microambiente TumoralRESUMEN
Mitochondrial DNA polymerase gamma (Pol gamma) is the sole polymerase responsible for replication of the mitochondrial genome. The study of human Pol gamma is of key importance to clinically relevant issues such as nucleoside analog toxicity and mitochondrial disorders such as progressive external ophthalmoplegia. The development of a recombinant form of the human Pol gamma holoenzyme provided an essential tool in understanding the mechanism of these clinically relevant phenomena using kinetic methodologies. This review will provide a brief history on the discovery and characterization of human mitochondrial DNA polymerase gamma, focusing on kinetic analyses of the polymerase and mechanistic data illustrating structure-function relationships to explain drug toxicity and mitochondrial disease.
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Fármacos Anti-VIH/efectos adversos , ADN Mitocondrial/genética , ADN Polimerasa Dirigida por ADN/metabolismo , Mitocondrias/efectos de los fármacos , Mitocondrias/enzimología , Enfermedades Mitocondriales/inducido químicamente , ADN Polimerasa gamma , HumanosRESUMEN
We used on-line electron capture dissociation (ECD) for the large scale identification and localization of sites of phosphorylation. Each FT-ICR ECD event was paired with a linear ion trap collision-induced dissociation (CID) event, allowing a direct comparison of the relative merits of ECD and CID for phosphopeptide identification and site localization. Linear ion trap CID was shown to be most efficient for phosphopeptide identification, whereas FT-ICR ECD was superior for localization of sites of phosphorylation. The combination of confident CID and ECD identification and confident CID and ECD localization is particularly valuable in cases where a phosphopeptide is identified just once within a phosphoproteomics experiment.
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Espectrometría de Masas/métodos , Proteínas/metabolismo , Secuencia de Aminoácidos , Animales , Ratones , Datos de Secuencia Molecular , Células 3T3 NIH , Fosfopéptidos/análisis , Fosfopéptidos/química , Fosforilación , Proteínas/química , Reproducibilidad de los ResultadosRESUMEN
Fms-like tyrosine-like kinase 3 internal tandem duplication (FLT3-ITD) is present in acute myeloid leukemia (AML) in 30% of patients and is associated with short disease-free survival. FLT3 inhibitor efficacy is limited and transient but may be enhanced by multitargeting of FLT3-ITD signaling pathways. FLT3-ITD drives both STAT5-dependent transcription of oncogenic Pim-1 kinase and inactivation of the tumor-suppressor protein phosphatase 2A (PP2A), and FLT3-ITD, Pim-1, and PP2A all regulate the c-Myc oncogene. We studied mechanisms of action of cotreatment of FLT3-ITD-expressing cells with FLT3 inhibitors and PP2A-activating drugs (PADs), which are in development. PADs, including FTY720 and DT-061, enhanced FLT3 inhibitor growth suppression and apoptosis induction in FLT3-ITD-expressing cell lines and primary AML cells in vitro and MV4-11 growth suppression in vivo PAD and FLT3 inhibitor cotreatment independently downregulated c-Myc and Pim-1 protein through enhanced proteasomal degradation. c-Myc and Pim-1 downregulation was preceded by AKT inactivation, did not occur in cells expressing myristoylated (constitutively active) AKT1, and could be induced by AKT inhibition. AKT inactivation resulted in activation of GSK-3ß, and GSK-3ß inhibition blocked downregulation of both c-Myc and Pim-1 by PAD and FLT3 inhibitor cotreatment. GSK-3ß activation increased c-Myc proteasomal degradation through c-Myc phosphorylation on T58; infection with c-Myc with T58A substitution, preventing phosphorylation, blocked downregulation of c-Myc by PAD and FLT3 inhibitor cotreatment. GSK-3ß also phosphorylated Pim-1L/Pim-1S on S95/S4. Thus, PADs enhance efficacy of FLT3 inhibitors in FLT3-ITD-expressing cells through a novel mechanism involving AKT inhibition-dependent GSK-3ß-mediated increased c-Myc and Pim-1 proteasomal degradation.
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Genes myc/genética , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Inhibidores de Proteínas Quinasas/uso terapéutico , Proteína Fosfatasa 2/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Proteínas Proto-Oncogénicas c-pim-1/antagonistas & inhibidores , Animales , Proliferación Celular , Humanos , Ratones , Ratones Endogámicos NOD , Inhibidores de Proteínas Quinasas/farmacología , Transducción de Señal , TransfecciónRESUMEN
Four double-drug HIV NRTI/NNRTI inhibitors 15a-d of the type [d4U]-spacer-[HI-236] in which the spacer is varied as 1-butynyl (15a), propargyl-1-PEG (15b), propargyl-2-PEG (15c) and propargyl-4-PEG (15d) have been synthesized and biologically evaluated as RT inhibitors against HIV-1. The key step in their synthesis involved a Sonogashira coupling of 5-iodo d4U's benzoate with an alkynylated tethered HI-236 precursor followed by introduction of the HI-236 thiourea functionality. Biological evaluation in both cell-culture (MT-2 cells) as well as using an in vitro RT assay revealed 15a-c to be all more active than d4T. However, overall the results indicate the derivatives are acting as chain-extended NNRTIs in which for 15b-d the nucleoside component is likely situated outside of the pocket but with no evidence for any synergistic double binding between the NRTI and NNRTI sites. This is attributed, in part, to the lack of phosphorylation of the nucleoside component of the double-drug as a result of kinase recognition failure, which is not improved upon with the phosphoramidate of 15d incorporating a 4-PEG spacer.
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Fármacos Anti-VIH/química , Transcriptasa Inversa del VIH/antagonistas & inhibidores , VIH-1/enzimología , Piridinas/química , Inhibidores de la Transcriptasa Inversa/química , Tiourea/análogos & derivados , Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/toxicidad , Sitios de Unión , Línea Celular , Simulación por Computador , Diseño de Fármacos , Transcriptasa Inversa del VIH/metabolismo , Humanos , Polietilenglicoles/química , Piridinas/síntesis química , Piridinas/farmacología , Inhibidores de la Transcriptasa Inversa/síntesis química , Inhibidores de la Transcriptasa Inversa/farmacología , Tiourea/síntesis química , Tiourea/química , Tiourea/farmacologíaRESUMEN
Type VI secretion is a newly described mechanism for protein transport across the cell envelope of Gram-negative bacteria. Components that have been partially characterised include an IcmF homologue, the ATPase ClpV, a regulatory FHA domain protein and the secreted VgrG and Hcp proteins. Type VI secretion is clearly a key virulence factor for some important pathogenic bacteria and has been implicated in the translocation of a potential effector protein into eukaryotic cells by at least one organism (Vibrio cholerae). However, type VI secretion systems (T6SSs) are widespread in nature and not confined to known pathogens. In accordance with the general rule that the expression of protein secretion systems is tightly regulated, expression of type VI secretion is controlled at both transcriptional and post-transcriptional levels.
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Proteínas Bacterianas/metabolismo , Proteínas Portadoras/metabolismo , Bacterias Gramnegativas/metabolismo , Bacterias Gramnegativas/patogenicidad , Factores de Virulencia/metabolismo , Animales , Proteínas Bacterianas/genética , Proteínas Portadoras/genética , Evolución Molecular , Regulación Bacteriana de la Expresión Génica , Bacterias Gramnegativas/genética , Infecciones por Bacterias Gramnegativas/microbiología , Humanos , Filogenia , Transporte de Proteínas , Factores de Virulencia/genéticaRESUMEN
xBASE is a genome database aimed at helping laboratory-based bacteriologists make best use of bacterial genome sequence data, with a particular emphasis on comparative genomics. The latest version, xBASE 2.0 (http://xbase.bham.ac.uk), now provides comprehensive coverage of all bacterial genomes and features an updated modularized backend and an improved user interface, which includes a taxonomy browser and a powerful full-text search facility.