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OBJECTIVE: Preparation for transition from pediatric to adult cystic fibrosis (CF) care is essential for successful self-management in adulthood. The primary objective of this study was to determine if education improved performance on follow-up assessments to increase knowledge for transition into adult care. The secondary objective of this study was to identify areas of greatest educational opportunity for adolescent CF patients. METHODS: A knowledge assessment containing 13 multiple-choice questions was given to patients between 14 and 19 years of age. Three educational handouts covering topics including nutrition, pancreatic enzyme replacement therapy, or vitamins were provided when a question corresponding to the topic was answered incorrectly. The same assessment was completed at the next clinic appointment as a follow-up. The scores of initial and follow-up assessments were compared based on number of correct answers. Additionally, the number of educational handouts provided was analyzed to determine area of greatest educational need. RESULTS: The average score ± SD on the initial assessment was 8.3 ± 1.6 of 13 questions answered correctly. For patients who completed both assessments, scores improved significantly between initial and follow-up assessments (8.4 ± 1.8 before education vs 10.3 ± 1.1 after; p = 0.0008). Nutrition, pancreatic enzyme, and vitamin handouts were given to 14 (70%), 17 (85%), and 20 (100%) patients, respectively. CONCLUSIONS: This pharmacist-driven educational initiative increased knowledge assessment scores after education was provided. Future studies of similar knowledge assessments starting at younger ages and other disease topics may determine if targeted education is the optimal way to build knowledge for transition to adult CF care.
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Cell membrane lipid composition, especially cholesterol, affects many functions of embedded enzymes, transporters and receptors in red blood cells (RBC). High membrane cholesterol content affects the RBCs' main vital function, O2 and CO2 transport and delivery, with consequences on peripheral tissue physiology and pathology. A high degree of deformability of RBCs is required to accommodate the size of micro-vessels with diameters significantly lower than RBCs. The potential therapeutic role of high-density lipoproteins (HDL) in the removal of cholesterol and its activity regarding maintenance of an optimal concentration of RBC membrane cholesterol have not been well investigated. On the contrary, the focus for HDL research has mainly been on the clearance of cholesterol accumulated in atherosclerotic macrophages and plaques. Since all interventions aiming at decreasing cardiovascular diseases by increasing the plasma level of HDL cholesterol have failed so far in large outcome studies, we reviewed the potential role of HDL to remove excess membrane cholesterol from RBC, especially in sickle cell disease (SCD). Indeed, abundant literature supports a consistent decrease in cholesterol transported by all plasma lipoproteins in SCD, in addition to HDL, low- (LDL) and very low-density lipoproteins (VLDL). Unexpectedly, these decreases in plasma were associated with an increase in RBC membrane cholesterol. The concentration and activity of the main enzyme involved in the removal of cholesterol and generation of large HDL particles-lecithin cholesterol ester transferase (LCAT)-are also significantly decreased in SCD. These observations might partially explain the decrease in RBC deformability, diminished gas exchange and tendency of RBCs to aggregate in SCD. We showed that incubation of RBC from SCD patients with human HDL or the HDL-mimetic peptide Fx5A improves the impaired RBC deformability and decreases intracellular reactive oxygen species levels. We propose that the main physiological role of HDL is to regulate the cholesterol/phospholipid ratio (C/PL), which is fundamental to the transport of oxygen and its delivery to peripheral tissues.
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The Dutch Diagnostic Instrument for Mild Aphasia (DIMA-nl) is a standardized battery recently created for evaluating the language performance of patients during the perioperative period of glioma surgery. Our aim was to establish normative data for the DIMA-fr, a French version of the DIMA-nl. The DIMA-nl was first adapted to French. The 14 subtasks of the DIMA-fr were then administered to 391 participants recruited from the general French population. The effects of sex, age and level of education were determined by analysis of variance (ANOVA). Normative data were computed as means, medians, standard deviations and percentiles. Our results demonstrated that age and level of education had an effect on the performance of all subtests but not sex. We thus stratified the norms into four different groups: (i) 18-69 years-old with Baccalauréat (Bac, the French High School Diploma) (n = 246); (ii) 18-69 years-old without Bac (n = 70); (iii) >70 years-old with Bac (n = 48); (iv) >70 years-old without Bac (n = 27). The DIMA-fr is thus the first standardized French battery of tests to specifically assess language during the perioperative period of awake glioma surgery. However, to be used in the clinic, the DIMA-fr must now be validated in patients. The DIMA, which is currently standardized in several languages, could become a reference tool for international studies.
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Afasia , Glioma , Adolescente , Adulto , Anciano , Afasia/diagnóstico , Humanos , Lenguaje , Persona de Mediana Edad , Estándares de Referencia , Reproducibilidad de los Resultados , Adulto JovenRESUMEN
OBJECTIVE: Vaso-occlusive crisis (VOC) is the most common problem reported by patients with sickle cell disease (SCD). The objective of this study was to evaluate the impact of individualized pain plans in pediatric patients with SCD admitted for VOC. METHODS: This was a pre- and post-study of patients with SCD admitted to Riley Hospital for Children for VOC from July 1, 2019, through July 1, 2020. The primary outcome was length of inpatient stay for VOC. Secondary outcomes included final pain score, days on scheduled opioids, days on breakthrough opioids, and average morphine milligram equivalents (MME) used per day. RESULTS: Nine patients were included. The mean age was 16 years (range, 10-20 years). Key clinical findings were decreases in median [IQR] for final pain scores (7 [4.5-9] vs 6 [2.5-8], p = 0.396) and number of days of breakthrough opioid use (5 [3-8] vs 4 [2.5-5.5], p = 0.233). Following implementation of an individualized pain plan, there was an increase in median average MME per day (65.94 [53.1-97.7] vs 82.85 [41-114.3], p = 0.844). Median length of stay and days on scheduled opioids remained the same. CONCLUSIONS: This study demonstrated that use of individualized pain plans in a small population of patients with SCD might result in decreased pain scores and decreased days on breakthrough opioids.
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The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) 3CL protease is a promising target for inhibition of viral replication by interaction with a cysteine residue (Cys145) at its catalytic site. Dalcetrapib exerts its lipid-modulating effect by binding covalently to cysteine 13 of a cholesteryl ester transfer protein. Because 12 free cysteine residues are present in the 3CL protease, we investigated the potential of dalcetrapib to inhibit 3CL protease activity and SARS-CoV-2 replication. Molecular docking investigations suggested that dalcetrapib-thiol binds to the catalytic site of the 3CL protease with a delta G value of -8.5 kcal/mol. Dalcetrapib inhibited both 3CL protease activity in vitro and viral replication in Vero E6 cells with IC50 values of 14.4 ± 3.3 µM and an EC50 of 17.5 ± 3.5 µM (mean ± SD). Near-complete inhibition of protease activity persisted despite 1000-fold dilution after ultrafiltration with a nominal dalcetrapib-thiol concentration of approximately 100 times below the IC50 of 14.4 µM, suggesting stable protease-drug interaction. The inhibitory effect of dalcetrapib on the SARS-CoV-2 3CL protease and viral replication warrants its clinical evaluation for the treatment of COVID-19.
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BACKGROUND: Exposure to patient or user suicide (PUS) is identified as a challenging occupational hazard for mental health and social work professionals. Professionals exposed to PUS may encounter several ranges of emotional, traumatic or professional impacts in the aftermath. A high proportion of exposed professionals reports a lack of support in the aftermath of PUS. SUPPORT is a postvention program designed to provide a comprehensive, adaptative and effective support to professionals impacted by PUS. The aims of the SUPPORT-S study are to (1) improve the design of the SUPPORT program, (2) evaluate the effectiveness of the program to buffer the emotional, traumatic and professional impacts and to improve the perceived social support for professionals exposed to PUS, and (3) provide more insights into the consequences of PUS on both professionals and organizations. METHOD: The SUPPORT-S study is a mixed method collaborative and participatory action research. The simultaneous and complementary collection and analysis of qualitative and quantitative data will offer an in-depth evaluation of the implementation and the effectiveness of the program. The qualitative evaluation includes: (a) an ethnographic observation; (b) 25 semi-directed interviews with randomized participants; (c) an activity analysis with providers of the program; and (d) collaborative sharing of the results with providers and participants. The quantitative evaluation includes pre- and post-measures in participants of: (a) emotional impact (Differential Emotions Scale IV); (b) traumatic impact (Impact of Event Scale-Revised); (c) professional impact (non-validated questionnaire); and (d) perceived social support (Perceived Social Support Scale for Professionals). The action research design will rely on: (a) the cycling process of implementation/evaluation/data sharing/adjustment and (b) the participatory approach through data sharing with providers and participants. Triangulation, saturation, randomization, and participatory design will also reduce the risk of biases and will improve the generalizability of conclusions. EXPECTED RESULTS: We expect the SUPPORT-S study to evaluate and improve the design of the SUPPORT program to effectively help professionals to cope with PUS. CONCLUSION: The results of the study will allow us to disseminate an effective and adaptive postvention program for professionals and institutions encountering PUS.
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Inhibition of cholesteryl ester transfer protein (CETP) increases HDL cholesterol (HDL-C) levels. However, the circulating CETP level varies and the impact of its inhibition in species with high CETP levels on HDL structure and function remains poorly characterized. This study investigated the effects of dalcetrapib and anacetrapib, the two CETP inhibitors (CETPis) currently being tested in large clinical outcome trials, on HDL particle subclass distribution and cholesterol efflux capacity of serum in rabbits and monkeys. New Zealand White rabbits and vervet monkeys received dalcetrapib and anacetrapib. In rabbits, CETPis increased HDL-C, raised small and large α-migrating HDL, and increased ABCA1-induced cholesterol efflux. In vervet monkeys, although anacetrapib produced similar results, dalcetrapib caused opposite effects because the LDL-C level was increased by 42% and HDL-C decreased by 48% (P < 0.01). The levels of α- and preß-HDL were reduced by 16% (P < 0.001) and 69% (P < 0.01), resulting in a decrease of the serum cholesterol efflux capacity. CETPis modulate the plasma levels of mature and small HDL in vivo and consequently the cholesterol efflux capacity. The opposite effects of dalcetrapib in different species indicate that its impact on HDL metabolism could vary greatly according to the metabolic environment.
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HDL-Colesterol/química , HDL-Colesterol/metabolismo , Oxazolidinonas/farmacología , Compuestos de Sulfhidrilo/farmacología , Amidas , Animales , Apolipoproteína A-I/metabolismo , Transporte Biológico/efectos de los fármacos , Chlorocebus aethiops , Proteínas de Transferencia de Ésteres de Colesterol/metabolismo , Ésteres , Células Hep G2 , Humanos , Masculino , Conejos , Especificidad de la EspecieRESUMEN
From Hiroshima bomb explosion data, the risk of radiation-induced cancer is significant from 100 mSv for a population considered as uniform and radioresistant. However, the recent radiobiological data bring some new elements that highlight some features that were not taken into account: the individual factor, the dose rate and the repeated dose effect. The objective evaluation of the cancer risk due to doses lower than 100 mSv is conditioned by high levels of measurability and statistical significance. However, it appears that methodological rigor is not systematically applied in all the papers. Furthermore, unclear communication in press often leads to some announcement effects, which does not improve the readability of the issue. This papers aims to better understand the complexity of the low-dose-specific phenomena as a whole, by confronting the recent biological data with epidemiological data.
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Neoplasias Inducidas por Radiación/etiología , Dosis de Radiación , Tolerancia a Radiación , Adaptación Fisiológica , Astronautas , Relación Dosis-Respuesta en la Radiación , Exposición a Riesgos Ambientales , Personal de Salud , Hormesis/fisiología , Humanos , Modelos Animales , Enfermedades Profesionales/etiología , Exposición Profesional/efectos adversos , Ceniza Radiactiva/efectos adversos , Liberación de Radiactividad Peligrosa , Radiactividad , Dosificación Radioterapéutica , Medición de RiesgoRESUMEN
PURPOSE: Cholesterol efflux from macrophages to HDL, measured in vitro, is augmented by treatment with agents which raise HDL cholesterol. In vitro, cholesterol depletion by statins is known to trigger a positive feedback on the cholesterol synthetic pathway via sterol regulatory element-binding protein (SREBP) transcription and changes in expression of SREBP regulated genes including microRNA33 (miR33) which is co-transcribed with SREBP and down-regulates ABCA1 and ABCG1 expression. METHODS: We investigated whether miR33 up-regulation, associated with SREBP increased transcription by statins, reduces macrophage ATP-binding cassette (ABC) transporter expression, thereby decreasing HDL-mediated cholesterol efflux at the tissue level. RESULTS: In human macrophage THP-1 cells cholesterol-loaded with acetylated LDL, incubation with 1 µM atorvastatin increased miR33 by 33 % (P < 0.05), and decreased ABCA1 messenger RNA (mRNA) and ABCG1 mRNA by 47 % (P < 0.05) and 27 % (NS), respectively. In J774A.1 mouse macrophage, labelled with 3H-cholesterol, ABCA1 mRNA and ABCA1-mediated cholesterol efflux were decreased by 1 µM statin: simvastatin > pitavastatin > atorvastatin > rosuvastatin > pravastatin. HDL incubated with rhCETP and dalcetrapib increased ABCA1-mediated cholesterol efflux. However, incremental simvastatin concentrations decreased cholesterol efflux to HDL treated with rhCETP and dalcetrapib. When HDL was incubated with rhCETP, addition of dalcetrapib augmented ABCA1-mediated cholesterol efflux from J774A.1 macrophages. However, simvastatin ≥1 µM virtually eliminated any HDL-ABCA1-mediated cholesterol efflux and any augmentation of that process by dalcetrapib. CONCLUSIONS: In vitro, statins increase miR33 expression, and decrease ABCA1 expression and cholesterol efflux from peripheral tissues; this may counteract the potential benefit of agents that raise HDL and apolipoprotein A-I in statin-treated patients.
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Transportador 1 de Casete de Unión a ATP/metabolismo , Colesterol/metabolismo , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Lipoproteínas HDL/metabolismo , MicroARNs/metabolismo , Simvastatina/farmacología , Transportador 1 de Casete de Unión a ATP/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 1 , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Animales , Línea Celular , Humanos , Ratones , ARN Mensajero/metabolismo , Receptores de LDL/genéticaRESUMEN
Carrion insect succession patterns have long been used to estimate the postmortem interval (PMI) during a death investigation. However, no published carrion succession study included sufficient replication to calculate a confidence interval about a PMI estimate based on occurrence data. We exposed 53 pig carcasses (16±2.5 kg), near the likely minimum needed for such statistical analysis, at a site in north-central Indiana, USA, over three consecutive summer seasons. Insects and Collembola were sampled daily from each carcass for a total of 14 days, by this time each was skeletonized. The criteria for judging a life stage of a given species to be potentially useful for succession-based PMI estimation were (1) nonreoccurrence (observed during a single period of presence on a corpse), and (2) found in a sufficiently large proportion of carcasses to support a PMI confidence interval. For this data set that proportion threshold is 45/53. Of the 266 species collected and identified, none was nonreoccuring in that each showed at least a gap of one day on a single carcass. If the definition of nonreoccurrence is relaxed to include such a single one-day gap the larval forms of Necrophilaamericana, Fanniascalaris, Cochliomyia macellaria, Phormiaregina, and Luciliaillustris satisfied these two criteria. Adults of Creophilus maxillosus, Necrobiaruficollis, and Necrodessurinamensis were common and showed only a few, single-day gaps in occurrence. C.maxillosus, P.regina, and L.illustris displayed exceptional forensic utility in that they were observed on every carcass. Although these observations were made at a single site during one season of the year, the species we found to be useful have large geographic ranges. We suggest that future carrion insect succession research focus only on a limited set of species with high potential forensic utility so as to reduce sample effort per carcass and thereby enable increased experimental replication.
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Escarabajos , Dípteros , Conducta Alimentaria , Cambios Post Mortem , Animales , Intervalos de Confianza , Entomología , Patologia Forense , Humanos , Larva , PorcinosRESUMEN
Cholesteryl ester transfer protein (CETP), a key regulator of high-density lipoprotein (HDL) metabolism, induces HDL remodeling by transferring lipids between apolipoprotein B-containing lipoproteins and HDL, and/or by promoting lipid transfer between HDL subparticles. In this study, we investigated the mechanism as to how CETP induces the generation of lipid-poor particles (pre-ß-HDL) from HDL, which increases ATP-binding cassette transporter 1-mediated cholesterol efflux. This CETP-dependent HDL remodeling is enhanced by the CETP modulator dalcetrapib both in plasma and isolated HDL. The interaction of dalcetrapib with cysteine 13 of CETP is required, since this effect was abolished when using mutant CETP in which cysteine 13 was substituted for a serine residue. Other thiol-containing compounds were identified as CETP modulators interacting with cysteine 13 of CETP. In order to mimic dalcetrapib-bound CETP, mutant CETP proteins were prepared by replacing cysteine 13 with the bulky amino acid tyrosine or tryptophan. The resultant mutants showed virtually no CETP-dependent lipid transfer activity but demonstrated preserved CETP-dependent pre-ß-HDL generation. Overall, these data demonstrate that the two functions of CETP i.e., cholesteryl ester transfer and HDL remodeling can be uncoupled by interaction of thiol-containing compounds with cysteine 13 of CETP or by introducing large amino acid residues in place of cysteine 13.
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Proteínas de Transferencia de Ésteres de Colesterol/química , Proteínas de Transferencia de Ésteres de Colesterol/metabolismo , Colesterol/metabolismo , Cisteína/química , Lipoproteínas HDL/metabolismo , Transporte Biológico/genética , Transporte Biológico/fisiología , Línea Celular , Proteínas de Transferencia de Ésteres de Colesterol/genética , Cisteína/genética , Humanos , Plasma , Relación Estructura-ActividadRESUMEN
BACKGROUND: Transoral robotic surgery (TORS) is a recent endoscopic technique to resect selected head and neck cancers. STUDY DESIGN: In total, 13 patients underwent TORS procedure for resection of head and neck cancers of various localizations, within the ENT Department of Limoges University Hospital Center between March and October 2010. RESULTS: Tumor localizations were aryepiglottic fold (n = 3), pyriform sinus (n = 2), posterior pharyngeal wall (n = 2), base of tongue (n = 2), lateral pharyngeal wall (n = 2), vallecula (n = 1), and epiglottis (n = 1). Average TORS setup time was 23 minutes. Average TORS operative time was 45 minutes. Average hospital stay was 8.4 days. CONCLUSIONS: TORS is a new technique that permits excellent resection of selected head and neck cancers with poor morbidity. Future reports on long-term oncologic and functional outcomes are needed to assess the risks and benefits of this approach compared with external approaches and nonsurgical alternatives.
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Carcinoma de Células Escamosas/cirugía , Neoplasias de Cabeza y Cuello/cirugía , Procedimientos Quirúrgicos Otorrinolaringológicos/métodos , Robótica/métodos , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Procedimientos Quirúrgicos Otorrinolaringológicos/instrumentación , Robótica/instrumentación , Resultado del TratamientoRESUMEN
OBJECTIVE: The increased mortality observed with the cholesteryl ester transfer protein inhibitor torcetrapib is partly due to increased aldosterone production and blood pressure. The mechanisms underlying these effects were investigated. METHODS: Cytochrome P450 subunit 11B2 (aldosterone synthase), extracellular signal-regulated kinase (p44/42) and voltage-gated Cachannel alpha subunit mRNA profiling, aldosterone production, cytosolic calcium and RNA interference were assessed in adrenocarcinoma human cells (H295R). Telemetry was conducted in spontaneously hypertensive rats. RESULTS: Torcetrapib and angiotensin II (Ang II) but not dalcetrapib (a structurally different cholesteryl ester transfer protein inhibitor) elevated both cytochrome P450 subunit 11B2 mRNA and aldosterone production in H295R cells at 6 h. At days 1-5, torcetrapib produced a sustained increase of cytochrome P450 subunit 11B2 mRNA, unlike Ang II. Although torcetrapib and Ang II potentiated the effect of 25-OH cholesterol and raised pregnenolone levels, torcetrapib increased neither cytosolic Ca at 5 min nor extracellular signal-regulated kinase1/2 phosphorylation, suggesting initially divergent pathways. Unlike Ang II, torcetrapib steroidogenesis was not affected by Ang II type 1 receptor antagonism or voltage-gated T-type Ca channel antagonism, but was blocked by several L-type Cachannel antagonists. In unbiased genome-wide screening, Ang II and torcetrapib modulated an overlapping but distinct set of genes in H295R cells. Torcetrapib, but not Ang II, upregulated mRNA levels of the L-type Ca channel alpha 1C subunit. In spontaneously hypertensive rat, torcetrapib had a potent hypertensive effect mediated by the L-type Ca channel. CONCLUSION: The unique steroidogenic and hypertensive side effects of torcetrapib may be linked and involve voltage-gated L-type Ca channels. Structurally unrelated cholesteryl ester transfer protein inhibitors such as dalcetrapib do not share this effect.
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Anticolesterolemiantes/farmacología , Canales de Calcio Tipo L/efectos de los fármacos , Proteínas de Transferencia de Ésteres de Colesterol/antagonistas & inhibidores , Hipertensión/tratamiento farmacológico , Quinolinas/farmacología , Corteza Suprarrenal/efectos de los fármacos , Corteza Suprarrenal/metabolismo , Corteza Suprarrenal/patología , Neoplasias de las Glándulas Suprarrenales , Aldosterona/metabolismo , Amidas , Angiotensina II/farmacología , Animales , Presión Sanguínea/efectos de los fármacos , Presión Sanguínea/fisiología , Calcio/metabolismo , Canales de Calcio Tipo L/metabolismo , Línea Celular Tumoral , Citocromo P-450 CYP11B2/biosíntesis , Citocromo P-450 CYP11B2/genética , Citosol/efectos de los fármacos , Citosol/metabolismo , Inducción Enzimática/efectos de los fármacos , Ésteres , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Expresión Génica/efectos de los fármacos , Perfilación de la Expresión Génica , Humanos , Canal de Sodio Activado por Voltaje NAV1.1 , Proteínas del Tejido Nervioso/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo , Ratas , Ratas Endogámicas SHR , Canales de Sodio/metabolismo , Relación Estructura-Actividad , Compuestos de Sulfhidrilo/farmacologíaRESUMEN
Dalcetrapib (RO4607381/JTT-705), an agent that targets cholesteryl ester transfer protein, is in development for prevention of cardiovascular events. In vitro studies were performed to identify receptors that mediate an off-target effect of dalcetrapib observed in preclinical models: increased lipid uptake into the lamina propria of the small intestine and into mesenteric lymph node macrophages. Uptake of oxidized low-density lipoprotein (LDL) cholesterol or dalcetrapib-treated chylomicrons was quantitated by triglyceride assay or fluorescent labeling in primary macrophages and the cell lines CHO, J774A.1 (mouse macrophages) and THP-1 (human macrophages). Quantitative reverse-transcriptase polymerase chain reaction and immunoblotting measured candidate receptor expression. Lectin-like oxidized LDL receptor (LOX-1) and scavenger receptor type AI (SR-AI) were excluded as candidate receptors based on lack of association between their expression and uptake of dalcetrapib-treated lipids. In J774A.1 cells, uptake of dalcetrapib-treated chylomicrons was increased by LPS and associated with expression of MAcrophage Receptor with COllagenous domain (MARCO). MARCO was expressed at very low levels in human macrophages and was not inducible by LPS. The MARCO receptor may account for the variable species susceptibility towards dalcetrapib-mediated chylomicron uptake by macrophages.
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Anticolesterolemiantes/farmacología , Metabolismo de los Lípidos/efectos de los fármacos , Macrófagos/metabolismo , Receptores Inmunológicos/fisiología , Compuestos de Sulfhidrilo/farmacología , Amidas , Aminoácido Oxidorreductasas/metabolismo , Animales , Western Blotting , Línea Celular , VLDL-Colesterol/metabolismo , Quilomicrones/metabolismo , Islas de CpG , Ésteres , Humanos , Interleucina-12/biosíntesis , Interleucina-4/biosíntesis , Factor Estimulante de Colonias de Macrófagos/biosíntesis , Macrófagos/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Oxidación-Reducción , ARN/biosíntesis , ARN/aislamiento & purificación , Ratas , Ratas Sprague-Dawley , Células TH1/efectos de los fármacosRESUMEN
Bile acids have been implicated in the development of colorectal cancers. We investigated the expression of the transcription factor regulated by bile acids, farnesoid X receptor (FXR), as well as other components of this pathway in human colorectal tumors and cell lines. The most significant changes were a decrease in FXR mRNA levels in adenomas (5-fold average) and carcinomas (10 fold average) and an increase in peroxisome proliferator activated receptor-gamma (2-fold average). FXR was not expressed in undifferentiated colon adenocarcinoma SW480 cells and metastasis derived SW620 cells. In Caco-2 and HT-29 cells, the level of FXR expression increased with the degree of differentiation. Intestinal bile acid binding protein was activated by chenodeoxycholic acid and the synthetic FXR agonist GW4064 in Caco-2 and HT-29 but not in SW cells unless FXR was transfected. The down-regulation of the nuclear receptor FXR in colon cancer might be of clinical and pharmacological importance.
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Adenocarcinoma/metabolismo , Neoplasias del Colon/metabolismo , Proteínas de Unión al ADN/metabolismo , Hidroxiesteroide Deshidrogenasas/metabolismo , Factores de Transcripción/metabolismo , Transportador 1 de Casete de Unión a ATP , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Línea Celular Tumoral/metabolismo , Proteínas de Unión al ADN/genética , Humanos , Hidroxiesteroide Deshidrogenasas/genética , Receptores X del Hígado , Persona de Mediana Edad , Receptores Nucleares Huérfanos , ARN Mensajero/genética , Receptores Citoplasmáticos y Nucleares/genética , Receptores Citoplasmáticos y Nucleares/metabolismo , Factores de Transcripción/genéticaRESUMEN
Apomine, a novel 1,1-bisphosphonate ester, has been shown to lower plasma cholesterol concentration in several species. Here we show that Apomine reduced the levels of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR), the rate-limiting enzyme in the mevalonate pathway, both in rat liver and in cultured cells. Apomine resembles sterols such as 25-hydroxycholesterol in its ability to potently accelerate the rate of HMGR degradation by the ubiquitin-proteasome pathway, a process that depends on the transmembrane domain of the enzyme. The similarity between Apomine and sterols in promoting rapid HMGR degradation extends to its acute requirements for ongoing protein synthesis and mevalonate-derived non-sterol product(s) as a co-regulator. Yet, at suboptimal concentrations, sterols potentiated the effect of Apomine in stimulating HMGR degradation, indicating that these agents act via distinct modes. Furthermore, unlike sterols, Apomine inhibited the activity of acyl-CoA:cholesterol acyltransferase in intact cells but not in cell-free extracts. Apomine stimulated the cleavage of the precursor of sterol-regulatory element-binding protein-2 and increased the activity of low density lipoprotein receptor pathway. This Apomine-enhanced activation of sterol-regulatory element-binding protein-2 was prevented by sterols or mevalonate. Taken together, our results provide a molecular mechanism for the hypocholesterolemic activity of Apomine.