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The integration of metal oxide nanomaterials with mesoporous silica is a promising approach to exploiting the advantages of both types of materials. Traditional synthesis methods typically require multiple steps. This work instead presents a fast, one-step, template-free method for the synthesis of metal oxides homogeneously dispersed within mesoporous silica, including oxides of W, Ti, Nb, Ta, Sn, and Mo. These composites have tunable metal oxide contents, large surface areas, and wide mesopores. The combination of Nb2O5 nanoparticles (NPs) with SiO2 results in an increased surface area and a larger number of acid sites compared to pure Nb2O5 NPs. The surface texture and acidity of the silica-niobia composites can be tuned by adjusting the Nb/Si molar ratio. Moreover, the silica provides protection to the niobia NPs, preventing sintering during thermal treatment at 400 °C. The silica-niobia materials exhibit superior performance as catalysts in the aldol condensation of furfural (Fur) with acetone compared to pure niobia, leading to an up to 62% in product yield. Additionally, these catalysts show remarkable stability, retaining their performance over multiple runs. This work demonstrates the potential of the proposed synthesis approach for preparing more sustainable, high-performance, durable, and stable nanoscale metal oxide-based catalysts with a tunable composition, surface area, and active site density.
ABSTRACT
CuO-based nanostructures have been widely investigated in catalysis, sensing, and energy conversion and storage in recent years. The unique properties of these nanostructures are largely related to the morphology and crystallinity of CuO. The controlled deposition of conformal CuO thin films by atomic layer deposition (ALD) has remained challenging until now owing to the limited understanding of the nucleation behavior and growth process. Here, a novel ALD process for copper oxide was developed using copper(II) trifluoroacetylacetonate [Cu(tfacac)2] as the metal precursor. The nucleation and initial growth of a CuO film are strongly dependent on the surface OH concentration. A continuous particulate-like CuO film was grown on OH-abundant pristine SiO2 particles, whereas the surface of the annealed SiO2 particles (presenting mostly isolated OH groups) remained uncoated under the same growth conditions. Moreover, a uniform and conformal CuO film was grown on covalently functionalized CNTs under identical conditions as pristine SiO2 particles. This study provides a strategy for tailoring the structure and the properties of thin films via ALD, which is promising for designing well-tailored nanostructures for various applications.
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Background Sacubitril/valsartan, a first-in-class angiotensin receptor neprilysin inhibitor, received US Food and Drug Administration approval in 2015 for heart failure with reduced ejection fraction (HFrEF). Our objective was to describe the sacubitril/valsartan initiation rate, associated characteristics, and 6-month follow-up dosing among veterans with HFrEF who are renin-angiotensin-aldosterone system inhibitor (RAASi) naïve. Methods and Results Retrospective cohort study of veterans with HFrEF who are RAASi naïve defined as left ventricular ejection fraction (LVEF) ≤40%; ≥1 in/outpatient heart failure visit, first RAASi (sacubitril/valsartan, angiotensin-converting enzyme inhibitor [ACEI]), or angiotensin-II receptor blocker [ARB]) fill from July 2015 to June 2019. Characteristics associated with sacubitril/valsartan initiation were identified using Poisson regression models. From July 2015 to June 2019, we identified 3458 sacubitril/valsartan and 29 367 ACEI or ARB initiators among veterans with HFrEF who are RAASi naïve. Sacubitril/valsartan initiation increased from 0% to 26.5%. Sacubitril/valsartan (versus ACEI or ARB) initiators were less likely to have histories of stroke, myocardial infarction, or hypertension and more likely to be older and have diabetes mellitus and lower LVEF. At 6-month follow-up, the prevalence of ≥50% target daily dose for sacubitril/valsartan, ACEI, and ARB initiators was 23.5%, 43.2%, and 47.1%, respectively. Conclusions Sacubitril/valsartan initiation for HFrEF in the Veterans Administration increased in the 4 years immediately following Food and Drug Administration approval. Sacubitril/valsartan (versus ACEI or ARB) initiators had fewer baseline cardiovascular comorbidities and the lowest proportion on ≥50% target daily dose at 6-month follow-up. Identifying the reasons for lower follow-up dosing of sacubitril/valsartan could support guideline recommendations and quality improvement strategies for patients with HFrEF.
Subject(s)
Aminobutyrates/therapeutic use , Biphenyl Compounds/therapeutic use , Heart Failure , Valsartan/therapeutic use , Veterans , Aldosterone , Angiotensin Receptor Antagonists/therapeutic use , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Heart Failure/diagnosis , Heart Failure/drug therapy , Heart Failure/epidemiology , Humans , Renin-Angiotensin System , Retrospective Studies , Stroke Volume , Tetrazoles/therapeutic use , Ventricular Function, LeftABSTRACT
INTRODUCTION: Critical gaps exist in the understanding of the continuum of multiple sclerosis (MS) progression, particularly with regard to the patient experience prior to and during the transition from relapsing-remitting MS (RRMS) to secondary-progressive MS (SPMS) stages. To date, there are no clear diagnostic criteria in the determination of the clinical transition. We report here the use of patient experience data to support the development of a qualitative conceptual model of MS that describes the patient journey of transition from active-relapsing disease to progressive MS. METHODS: The study used a single-encounter, multicenter, qualitative observational study design that included a targeted literature review and individual, in-depth interviews with adult patients with a clinically confirmed diagnosis of SPMS and their adult care partners. Descriptions of symptoms and impacts of RRMS and SPMS were extracted from the literature review and used to support development of the interview guide and conceptual model. RESULTS: Participants described a slow progression in terms of change in symptoms over time, including both the development of new symptoms and the worsening of existing symptoms. CONCLUSIONS: The conceptual model of the transitionary period from RRMS to SPMS expands the current understanding of the progression of MS from the patient and care partner perspectives.
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Hydrogen is a fuel with a potentially zero-carbon footprint viewed as a viable alternative to fossil fuels. It can be produced in a large scale via electrochemical water splitting using electricity derived from renewable sources, but this would require highly active, inexpensive, and stable hydrogen evolution reaction (HER) catalysts to replace the Pt benchmark. Transition-metal phosphides (TMPs) are potential Pt replacements owing to their generally high activity as well as versatility as HER catalysts for different pH media. This review summarizes the recent progress in the development of TMP HER electrocatalysts, focusing on the strategies that have been recently explored to tune the activity in acidic, neutral, and basic media. These strategies are the doping of TMPs with metal and nonmetal elements, fabrication of multimetallic phosphide phases, and construction of multicomponent heterostructures comprising TMPs and another component such as a different TMP or a metal oxide/hydroxide. The synthetic methods utilized to design the catalysts are also presented. Finally, the challenges still remaining and future research directions are discussed.
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OBJECTIVE: The objective of this study was to describe and compare health care resource utilization (HCRU) and disease modifying treatment (DMT) use among US adults <65 years with multiple sclerosis (MS), across commercial and Medicare Advantage plans. METHODS: Medical and pharmacy claims data from commercial and Medicare Advantage with Part D (MAPD) plans were extracted for MS patients age 18 - 64 identified between 1 January 2014 and 31 May 2017. Comparisons were made between commercial and MAPD enrollees for all-cause HCRU and DMT use over 1 year, overall and by 5 year age groups. RESULTS: A total of 28,427 MS patients were identified; two-thirds (67%) had commercial coverage. MAPD patients had statistically significantly higher mean counts of all-cause inpatient, emergency room (ER) and ambulatory visits compared to commercial patients. The significant differences were evident in all age groups ≥30 years, except for ER visits in the 40-44 and 60-64 age groups. MAPD patients had statistically significantly lower prevalence of DMT use compared to commercial patients in all age groups starting at ≥35 years. CONCLUSION: MAPD patients had a higher burden of medical HCRU compared to their commercially insured counterparts, most likely due primarily to their more advanced disease state and higher level of MS-related disability. Reasons for lower prevalence of DMT use among MAPD patients may include their more advanced disease state, older age and higher prevalence of comorbid conditions compared with commercially insured patients, as well as more restrictive formularies for MAPD vs. commercial plans. These findings suggest that there may be an opportunity for recently approved DMTs indicated for active secondary progressive MS to fulfill an unmet need for treatment among MS patients <65 years without contraindicated comorbid conditions who are enrolled in MAPD plans. Novel therapies under development to delay progression may help keep MS patients of working age in the work force.
Subject(s)
Medicare Part C , Medicare Part D , Multiple Sclerosis , Adolescent , Adult , Aged , Humans , Multiple Sclerosis/drug therapy , Multiple Sclerosis/epidemiology , Patient Acceptance of Health Care , Retrospective Studies , United States/epidemiologyABSTRACT
BACKGROUND: US guidelines recommend that patients with heart failure with reduced ejection fraction (HFrEF), who tolerate an ACEI (angiotensin-converting enzyme inhibitor) or ARB (angiotensin II receptor blocker), be switched to sacubitril/valsartan to reduce morbidity and mortality. We compared characteristics and healthcare utilization between Veterans with HFrEF who were switched to sacubitril/valsartan versus maintained on an ACEI or ARB. METHODS: retrospective cohort study of treated HFrEF (July 2015-June 2017) using Veterans Affairs data. The index date was the first fill for sacubitril/valsartan and if none, for an ACEI or ARB. Treated HFrEF was defined by (1) left ventricular ejection fraction ≤40%, (2) ≥1 in/outpatient HF encounter, and (3) ≥1 ACEI or ARB fill, all within 1-year preindex. Poisson regression models were used to compare baseline characteristics and 1:1 propensity score-matched adjusted 4-month follow-up healthcare utilization between sacubitril/valsartan switchers and ACEI or ARB maintainers. RESULTS: Switchers (1612; 4.2%) were less likely than maintainers (37 065; 95.8%) to have a history of myocardial infarction or hypertension, and more likely to be black, have a lower left ventricular ejection fraction, and higher preindex healthcare utilization. Switchers were less likely to experience follow-up all-cause hospitalizations (11.2% versus 14.0%; risk ratio 0.80 [95% CI, 0.65-0.98], P value 0.035). CONCLUSIONS: Few Veterans with treated HFrEF were switched to sacubitril/valsartan within the first 2 years of Food and Drug Administration approval. Sacubitril/valsartan use was associated with a lower risk for all-cause hospitalizations at 4 months follow-up. Reasons for lack of guideline-recommended sacubitril/valsartan initiation warrant investigation and may reveal opportunities for HFrEF care optimization.
Subject(s)
Aminobutyrates/therapeutic use , Angiotensin II Type 1 Receptor Blockers/therapeutic use , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Drug Substitution , Heart Failure/drug therapy , Protease Inhibitors/therapeutic use , Stroke Volume , Tetrazoles/therapeutic use , Ventricular Function, Left , Veterans Health Services , Aged , Aminobutyrates/adverse effects , Angiotensin II Type 1 Receptor Blockers/adverse effects , Angiotensin-Converting Enzyme Inhibitors/adverse effects , Biphenyl Compounds , Disease Progression , Drug Combinations , Female , Health Status , Heart Failure/diagnosis , Heart Failure/mortality , Heart Failure/physiopathology , Hospitalization , Humans , Male , Middle Aged , Neprilysin/antagonists & inhibitors , Protease Inhibitors/adverse effects , Recovery of Function , Retrospective Studies , Risk Factors , Tetrazoles/adverse effects , Time Factors , Treatment Outcome , United States , United States Department of Veterans Affairs , ValsartanABSTRACT
INTRODUCTION: Sacubitril/valsartan has been established as an effective treatment for heart failure (HF) with reduced ejection fraction based on clinical trial data; however, little is known about its use or impact in real-world practice. METHODS: This study included data from medical and pharmacy claims and medical records review for patients (n = 200) who initiated sacubitril/valsartan between August 2015 and March 2016 preceding issuance of American College of Cardiology (ACC)/American Heart Association (AHA)/Heart Failure Society of America (HFSA) focused update on new pharmacological therapy for HF (May 2016), which included recommendations for sacubitril/valsartan. A within-subject analysis compared symptoms and healthcare resource utilization before and after treatment initiation. RESULTS: Patients treated with sacubitril/valsartan had multiple comorbidities, and nearly all had previous treatment for HF. Most patients initiated sacubitril/valsartan at the lowest dose of 24/26 mg twice a day (BID), which remained unchanged during the observation period for half of the patients. During the first 6 weeks of treatment, few patients discontinued sacubitril/valsartan treatment (5.5%), and only 17% achieved the target dose of 97/103 mg BID after 4 months of treatment. The proportion of patients with ≥ 1 all-cause inpatient stay decreased significantly between the pre-initiation period (27.5%) and the post-initiation period (17.0%), P = 0.009. Fatigue was noted in 51.8% of patients pre-initiation and 39.5% post-initiation, P = 0.027. Shortness of breath was documented for 66.7% of patients pre-initiation and 51.8% post-initiation, P = 0.008. CONCLUSION: The findings of this real-world investigation suggest sacubitril/valsartan is associated with symptom improvements and a reduction in hospitalizations within 4 months of treatment for patients with HF and reduced ejection fraction. FUNDING: Novartis Pharmaceuticals Corporation.
Subject(s)
Aminobutyrates/therapeutic use , Angiotensin II Type 1 Receptor Blockers/therapeutic use , Antihypertensive Agents/therapeutic use , Heart Failure/drug therapy , Stroke Volume/drug effects , Tetrazoles/therapeutic use , Valsartan/therapeutic use , Ventricular Dysfunction, Left/drug therapy , Aged , Biphenyl Compounds , Drug Combinations , Female , Humans , Male , Middle Aged , Retrospective Studies , Treatment Outcome , United StatesABSTRACT
The morphology of metal oxide nanostructures influences the response of the materials in a given application. In addition to changing the composition, doping can also modify the morphology of a host nanomaterial. Herein, we determine the effect of dopant concentration, reaction temperature, and reaction time on the morphology and assembly of CoxZn1−xO nanoparticles synthesized through non-aqueous sol-gel in benzyl alcohol. With the increase of the atom % of cobalt incorporated from 0 to 15, the shape of the nanoparticles changes from near spherical, to irregular, and finally to triangular. The tendency of the particles to assemble increases in the same direction, with Co0.05Zn0.95O consisting of non-assembled particles, whereas Co0.15Zn0.85O consists of triangular nanoparticles forming spherical structures. The morphology and assembly process are also sensitive to the reaction temperature. The assembly process is found to occur during the nucleation or the early stages of particle growth. The cobalt ions promote the change in the shape during the growth stage of the nanoparticles.
ABSTRACT
Transition-metal phosphides (TMPs) have recently emerged as efficient and inexpensive electrocatalysts for electrochemical water splitting. The synthesis of nanostructured phosphides often involves highly reactive and hazardous phosphorous-containing compounds. Herein, we report the synthesis of nickel phosphides through thermal treatment under H2(5%)/Ar of layered nickel phenylphosphonate (NiPh) or methylphosphonate (NiMe) that act as single-source precursors. Ni12P5, Ni12P5-Ni2P, and Ni2P nanoparticles (NPs) with sizes of ca. 15-45 nm coated with a thin shell of carbonaceous material were produced. Thermogravimetric analysis coupled with mass spectrometry (TG-MS) showed that H2, H2O, P2, and -C6H5 are the main compounds formed during the transformation of the precursor under argon and no hazard phosphorous-containing compounds are created, making this a simple and relatively safe route for fabricating nanostructured TMPs. The H2 most likely reacts with the -PO3 groups of the precursor to form H2O and P2, and the latter subsequently reacts with the metal to produce the phosphide. The Ni12P5-Ni2P and Ni2P NPs efficiently catalyze the hydrogen evolution reaction (HER), with Ni2P showing the best performance and generating a current density of 10 mA cm-2 at an overpotential of 87 mV and exhibiting long-term stability. Co2P and CoP NPs were also synthesized following this method. This approach may be utilized to explore the rich metal phosphonate chemistry for fabricating phosphide-based materials for electrochemical energy conversion and storage applications.
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INTRODUCTION: Prior research suggests increased costs during the final months of life, yet little is known about healthcare cost differences between patients with heart failure (HF) who die or survive. METHODS: A retrospective claims study from a large US health plan [commercial and Medicare Advantage with Part D (MAPD)] was conducted. Patients were ≥18 years old with two non-inpatient or one inpatient claim(s) with HF diagnosis code(s). The earliest HF claim date during 1 January 2010-31 December 2011 was the index date. Cohort assignment was based on evidence of death within 1 year (decedents) or survival for >1 year (survivors) post-index. Per-patient-per-month (PPPM) and 1-year (variable decedent follow-up) costs (all-cause and HF-related) were calculated up to 1 year post-index. Cohorts were matched on demographic and clinical characteristics. Independent samples t tests and Pearson's chi-square tests were used to examine cohort differences. RESULTS: Among patients with HF, 8344 survivors were 1:1 matched to decedents [mean age 75 years, 50% female, 88% MAPD; mean time to decedents' death: 150 (SD 105) days]. Compared to survivors, more decedents had no pharmacy claims for HF-related outpatient pharmacotherapy within 60 days post-index (42.1% vs. 27.1%; p < 0.001). Decedents also incurred higher all-cause medical costs (PPPM: $21,400 vs. $2663; 1 year: $60,048 vs. $32,394; both p < 0.001) and higher HF-related medical costs (PPPM: $16,477 vs. $1358; 1 year: $39,052 vs. $16,519; both p < 0.001). Hospitalizations accounted for more than half of all-cause PPPM medical costs (54.6% for survivors, 84.3% for decedents). CONCLUSION: Patients with HF who died within 1 year after an index HF encounter incurred markedly higher costs within 1 year (despite the much shorter post-index period) and PPPM costs than those who survived, with the majority of costs attributable to hospitalizations for both patient cohorts. There may be opportunities for improving outcomes in HF, considering higher use of pharmacotherapy and lower costs were seen among survivors.
Subject(s)
Health Expenditures/statistics & numerical data , Heart Failure/economics , Adolescent , Adult , Aged , Aged, 80 and over , Female , Health Services/economics , Health Services/statistics & numerical data , Hospitalization/economics , Humans , Insurance Claim Review , Male , Middle Aged , Retrospective Studies , Survivors , United States , Young AdultABSTRACT
BACKGROUND: Heart failure (HF) is a severe chronic disease with growing prevalence and health care burden as well as high mortality. End-of-life cost data for patients with HF may inform disease and medication therapy management. OBJECTIVES: To (a) characterize a real-world sample of patients with HF who died; (b) estimate health care costs for 6 months and semiannually for 24 months, before death; and (c) examine associations between patient characteristics and predeath health care costs. METHODS: This was a retrospective study of commercial and Medicare Advantage with Part D (MAPD) enrollees (aged ≥ 18 years), using data from a large national health plan. Included patients had evidence of HF during January 1, 2009-December 31, 2013, based on ≥ 1 inpatient hospitalization or ≥ 2 noninpatient encounters with diagnosis code for HF and evidence of mortality during July 1, 2009-December 31, 2013. Demographic data, comorbidities, guideline-directed HF-related outpatient pharmacotherapy (HFRx), and predeath health care costs (all-cause and HF-related) were described. A generalized linear model examined associations between all-cause health care costs (months 6 and 1 previous to death) and specific patient characteristics. RESULTS: Of 48,026 identified patients, mean age was 77.9 years; 52.8% were female; 93.0% were MAPD enrolled; 92.5% had Quan-Charlson comor-bidity score ≥ 3; and about one quarter (26.0%) had no evidence of HFRx. Over the last 6 months of life, monthly all-cause total cost increased 3.2-fold for MAPD enrollees and 2.8-fold for commercial enrollees, although pharmacy cost decreased slightly (0.8-fold for both plan types). Cumulative 6-month all-cause medical cost was $37,186 for MAPD enrollees and $143,363 for commercial enrollees (68.8% and 73.2% due to hospitalization, respectively), and cumulative HF-related medical cost was $20,794 for MAPD enrollees and $78,440 for commercial enrollees (88.8% and 95.3% due to hospitaliza-tion, respectively). Over the last 24 months, semiannual all-cause total cost increased 3.2-fold for MAPD enrollees and 4.5-fold for commercial enroll-ees, although pharmacy cost increased only slightly (1.1-fold and 1.3-fold, respectively). Based on multivariable analysis, factors associated with higher risk of incurring a cost increase between month 6 and month 1 before death included older age (75-84 years: cost ratio [CR] = 1.33, P < 0.001; 226585 years: CR = 1.43, P < 0.001), comorbid coronary heart disease (CR = 1.12, P = 0.003), and no evidence of HFRx (CR = 1.48, P < 0.001). CONCLUSIONS: Patients with HF experienced ≥ 2.8-fold increase in monthly all-cause total cost over the last 6 months of life, which was driven by hospitalization. Although MAPD enrollees incurred greater cost increases, cumulative costs were higher for commercial enrollees. After multivariable adjustment, older age, comorbid coronary heart disease, and no evidence of HFRx were among factors associated with higher risk of cost increase over the last 6 months of life. Study findings provide predeath cost information that should be useful in value assessments of innovative HF interventions and highlight impact of HFRx on predeath health care costs.
Subject(s)
Health Care Costs/trends , Heart Failure/economics , Heart Failure/mortality , Medicare Part D/economics , Medicare Part D/trends , Adolescent , Adult , Aged , Aged, 80 and over , Female , Heart Failure/therapy , Humans , Insurance Claim Review/economics , Insurance Claim Review/trends , Insurance, Health/economics , Insurance, Health/trends , Male , Medication Therapy Management/economics , Medication Therapy Management/trends , Middle Aged , Retrospective Studies , Terminal Care/economics , Terminal Care/trends , United States/epidemiology , Young AdultABSTRACT
TiO2 is frequently combined with carbon materials, such as reduced graphene oxide (RGO), to produce composites with improved properties, for example for photocatalytic applications. It is shown that heating conditions significantly affect the interface and photocatalytic properties of TiO2 @C, and that microwave irradiation can be advantageous for the synthesis of carbon-based materials. Composites of TiO2 with RGO or amorphous carbon were prepared from reaction of titanium isopropoxide with benzyl alcohol. During the synthesis of the TiO2 nanoparticles, the carbon is involved in reactions that lead to the covalent attachment of the oxide, the extent of which depends on the carbon characteristics, heating rate, and mechanism. TiO2 is more efficiently stabilized at the surface of RGO than amorphous carbon. Rapid heating of the reaction mixture results in a stronger coupling between the nanoparticles and carbon, more uniform coatings, and smaller particles with narrower size distributions. The more efficient attachment of the oxide leads to better photocatalytic performance.
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The acid-catalyzed reaction of 5-(hydroxymethyl)-2-furfural with ethanol is a promising route to produce biofuels or fuel additives within the carbohydrate platform; specifically, this reaction may give 5-ethoxymethylfurfural, 5-(ethoxymethyl)furfural diethylacetal, and/or ethyl levulinate (bioEs). It is shown that sulfonated, partially reduced graphene oxide (S-RGO) exhibits a more superior catalytic performance for the production of bioEs than several other acid catalysts, which include sulfonated carbons and the commercial acid resin Amberlyst-15, which has a much higher sulfonic acid content and stronger acidity. This was attributed to the cooperative effects of the sulfonic acid groups and other types of acid sites (e.g., carboxylic acids), and to the enhanced accessibility to the active sites as a result of the 2D structure. Moreover, the acidic functionalities bonded to the S-RGO surface were more stable under the catalytic reaction conditions than those of the other solids tested, which allowed its efficient reuse.
Subject(s)
Biofuels , Furaldehyde/analogs & derivatives , Graphite/chemistry , Oxides/chemistry , Sulfonic Acids/chemistry , Catalysis , Furaldehyde/chemistry , Levulinic Acids/chemistry , Oxidation-ReductionABSTRACT
Development of quantitative theory of adsorption-induced deformation is important, e.g., for enhanced coalbed methane recovery by CO2 injection. It is also promising for the interpretation of experimental measurements of elastic properties of porous solids. We study deformation of mesoporous silica by n-pentane adsorption. The shape of experimental strain isotherms for this system differs from the shape predicted by thermodynamic theory of adsorption-induced deformation. We show that this difference can be attributed to the difference of disjoining pressure isotherm, responsible for the solid-fluid interactions. We suggest the disjoining pressure isotherm suitable for n-pentane adsorption on silica and derive the parameters for this isotherm from experimental data of n-pentane adsorption on nonporous silica. We use this isotherm in the formalism of macroscopic theory of adsorption-induced deformation of mesoporous materials, thus extending this theory for the case of weak solid-fluid interactions. We employ the extended theory to calculate solvation pressure and strain isotherms for SBA-15 and MCM-41 silica and compare it with experimental data obtained from small-angle X-ray scattering. Theoretical predictions for MCM-41 are in good agreement with the experiment, but for SBA-15 they are only qualitative. This deviation suggests that the elastic modulus of SBA-15 may change during pore filling.
Subject(s)
Pentanes/chemistry , Silicon Dioxide/chemistry , Adsorption , Particle Size , Porosity , Surface Properties , ThermodynamicsABSTRACT
Pregnancy and its effects on breast cancer risk have been widely investigated; there is consensus among researchers that early pregnancy confers protection against breast cancer later in life, whereas nulliparity and late-age parity have been associated with increased risk of developing breast cancer. The answer to the question of how pregnancy reduces breast cancer risk has been elusive; however, pregnancy, like breast cancer, is a similar hormone-dependent entity under direct control of estrogen, progesterone and, of particular importance, human chorionic gonadotropin (hCG). In this report, we emphasize the main changes, previously described by our laboratory, in morphology and gene expression levels of the mammary gland of Sprague-Dawley rats exposed to known cancer-preventative conditions (pregnancy, hCG and progesterone + estrogen). In addition, we postulate a protective mechanism induced by hCG that could reduce the cell's potential to be transformed by carcinogens.
ABSTRACT
BACKGROUND: It is accepted that a woman's lifetime risk of developing breast cancer after menopause is reduced by early full term pregnancy and multiparity. This phenomenon is thought to be associated with the development and differentiation of the breast during pregnancy. METHODS: In order to understand the underlying molecular mechanisms of pregnancy induced breast cancer protection, we profiled and compared the transcriptomes of normal breast tissue biopsies from 71 parous (P) and 42 nulliparous (NP) healthy postmenopausal women using Affymetrix Human Genome U133 Plus 2.0 arrays. To validate the results, we performed real time PCR and immunohistochemistry. RESULTS: We identified 305 differentially expressed probesets (208 distinct genes). Of these, 267 probesets were up- and 38 down-regulated in parous breast samples; bioinformatics analysis using gene ontology enrichment revealed that up-regulated genes in the parous breast represented biological processes involving differentiation and development, anchoring of epithelial cells to the basement membrane, hemidesmosome and cell-substrate junction assembly, mRNA and RNA metabolic processes and RNA splicing machinery. The down-regulated genes represented biological processes that comprised cell proliferation, regulation of IGF-like growth factor receptor signaling, somatic stem cell maintenance, muscle cell differentiation and apoptosis. CONCLUSIONS: This study suggests that the differentiation of the breast imprints a genomic signature that is centered in the mRNA processing reactome. These findings indicate that pregnancy may induce a safeguard mechanism at post-transcriptional level that maintains the fidelity of the transcriptional process.
Subject(s)
Breast/metabolism , Gene Expression Profiling , Genome, Human/genetics , Parity/genetics , Aged , Cluster Analysis , Cyclins/genetics , Cyclins/metabolism , Down-Regulation/genetics , Female , Humans , Immunohistochemistry , Middle Aged , Oligonucleotide Array Sequence Analysis , Paraffin Embedding , Pregnancy , Reproducibility of Results , Reverse Transcriptase Polymerase Chain Reaction , Transcription Factors/genetics , Transcription Factors/metabolism , Transcriptome/genetics , Up-Regulation/geneticsABSTRACT
There's something in the air A nanocomposite consisting of well-dispersed SnO(2) and Pt nanoparticles on reduced graphene oxide (see the high-resolution TEM image) exhibited very high responses to hydrogen at concentrations between 0.5 and 3% in air, with response times of 3-7â s and recovery times of 2-6â s. The sensor was prepared by a straightforward microwave-assisted non-aqueous sol-gel approach.
ABSTRACT
Early pregnancy and multiparity are known to reduce the risk of women to develop breast cancer at menopause. Based on the knowledge that the differentiation of the breast induced by the hormones of pregnancy plays a major role in this protection, this work was performed with the purpose of identifying what differentiation-associated molecular changes persist in the breast until menopause. Core needle biopsies (CNB) obtained from the breast of 42 nulliparous (NP) and 71 parous (P) postmenopausal women were analyzed in morphology, immunocytochemistry and gene expression. Whereas in the NP breast, nuclei of epithelial cells were large and euchromatic, in the P breast they were small and hyperchromatic, showing strong methylation of histone 3 at lysine 9 and 27. Transcriptomic analysis performed using Affymetrix HG_U133 oligonucleotide arrays revealed that in CNB of the P breast, there were 267 upregulated probesets that comprised genes controlling chromatin organization, transcription regulation, splicing machinery, mRNA processing and noncoding elements including XIST. We concluded that the differentiation process induced by pregnancy is centered in chromatin remodeling and in the mRNA processing reactome, both of which emerge as important regulatory pathways. These are indicative of a safeguard step that maintains the fidelity of the transcription process, becoming the ultimate mechanism mediating the protection of the breast conferred by full-term pregnancy.
Subject(s)
Biomarkers/metabolism , Breast/cytology , Breast/metabolism , Cell Differentiation , Chromatin Assembly and Disassembly/genetics , Epithelial Cells/metabolism , Postmenopause/genetics , Aged , Female , Gene Expression Profiling , Humans , Middle Aged , Oligonucleotide Array Sequence Analysis , Parity/genetics , Pregnancy , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
The authors examined the comparative effectiveness of 4 angiotensin receptor blockers (ARBs) in patients with hypertension using a large electronic medical record database. Analysis of covariance and logistic multivariate regression models were used to estimate the blood pressure (BP) outcomes of 73,012 patients during 13 months of treatment with olmesartan, losartan, valsartan, and irbesartan. Results were adjusted by baseline BP, starting dose, year, age, sex, race, body mass index, comorbid conditions, and concomitant medications of patients. All ARBs led to sustained reductions in BP, but with significant differences in the magnitude of BP reduction. Raw mean systolic BP/diastolic BP reductions with losartan, valsartan, irbesartan, and olmesartan were 9.3/4.9 mm Hg, 10.4/5.6 mm Hg, 10.1/5.3 mm Hg, and 12.4/6.8 mm Hg, respectively. Adjusting for all covariates, the overall BP reductions with olmesartan were 1.88/0.86 mm Hg, 1.21/0.52 mm Hg, and 0.89/0.51 mm Hg greater than for losartan, valsartan, and irbesartan, respectively, and mean differences were higher for monotherapy: 2.43/1.16 mm Hg; 2.18/0.93 mm Hg; 1.44/0.91 mm Hg, respectively (all P values <.0001). Adjusted odds ratios of the JNC 7 goal attainment for losartan, valsartan, and irbesartan compared with olmesartan were 0.76, 0.86, and 0.91 (P<.05). Differences were also found in subpopulations: African Americans, diabetics, and obese/overweight patients but not all of these reached statistical significance. A broad choice of ARBs may be required to get patients to treatment goals.