122 research outputs found
Social cognitive career theory and higher education students’ entrepreneurial intention: The role of perceived educational support and perceived entrepreneurial opportunity
PURPOSE: This study aims to integrate insights from the Socio-Cognitive Career Theory (SCCT) and entrepreneurship literature to develop a research framework of how perceived entrepreneurial opportunities (PEO) and perceived educational support (PES) shape the progression of entrepreneurial self-efficacy (ESE) and entrepreneurial career interests (ECI). Additionally, this study investigates whether ECI mediates the effects of PEO and PES on entrepreneurial intention (EI) and how PEO and PES moderate the effects of ESE and ECI on EI. METHODOLOGY: A sample of 888 university students was recruited from Vietnam. Cronbach’s alpha and confirmatory factor analyses were adopted to test the reliability and validity of the scales. Structural equation modeling (SEM) is then used to test formulated hypotheses. FINDINGS: The current study demonstrates that ESE and ECI directly trigger EI. Although PES and PEO did not directly impact EI, their influence on EI was mediated through ESE and ECI. In addition, PEO was found to act as a positive catalyst for the transformation of ESE and ECI into EI. The greater the entrepreneurial opportunities students perceive, the more likely they are to convert ESE and ECI into intentions to become entrepreneurs. IMPLICATIONS: This study makes a significant contribution by emphasizing the relevance of the SCCT framework in understanding entrepreneurship and brings to the forefront the role of PES and PEO in shaping the progression of ESE, ECI and, ultimately, EI. In addition, the findings of this study provide practical implications for nascent entrepreneurs, entrepreneurship educators, and policymakers. ORIGINALITY AND VALUE: This study is one of the first to investigate the role of PEO and PES in the development of Vietnamese students’ SES, ECI and, ultimately, their intention to engage in entrepreneurship
Saliva-based detection of COVID-19 infection in a real-world setting using reagent-free Raman spectroscopy and machine learning
ABSTRACT: SIGNIFICANCE: The primary method of COVID-19 detection is reverse transcription polymerase chain reaction (RT-PCR) testing. PCR test sensitivity may decrease as more variants of concern arise and reagents may become less specific to the virus. AIM: We aimed to develop a reagent-free way to detect COVID-19 in a real-world setting with minimal constraints on sample acquisition. The machine learning (ML) models involved could be frequently updated to include spectral information about variants without needing to develop new reagents. APPROACH: We present a workflow for collecting, preparing, and imaging dried saliva supernatant droplets using a non-invasive, label-free technique-Raman spectroscopy-to detect changes in the molecular profile of saliva associated with COVID-19 infection. RESULTS: We used an innovative multiple instance learning-based ML approach and droplet segmentation to analyze droplets. Amongst all confounding factors, we discriminated between COVID-positive and COVID-negative individuals yielding receiver operating coefficient curves with an area under curve (AUC) of 0.8 in both males (79% sensitivity and 75% specificity) and females (84% sensitivity and 64% specificity). Taking the sex of the saliva donor into account increased the AUC by 5%. CONCLUSION: These findings may pave the way for new rapid Raman spectroscopic screening tools for COVID-19 and other infectious diseases
Conformational Space and Photochemistry of α-Terpinene
α-Terpinene is a natural product that is isolated from a variety of plant sources and is used in the pharmaceutical and perfume industries. In the atmosphere, under the influence of sunlight, α-terpinene undergoes a series of photochemical transformations and contributes to the formation of the secondary organic aerosols. In the present work, α-terpinene has been isolated in low-temperature xenon and argon matrices, and its structure and photochemistry were characterized with the aid of FTIR spectroscopy and DFT calculations. The theory predicts three conformers resulting from the rotation of the exocyclic CH(CH3)2 framework, that is, Trans (T) and Gauche (G+ and G−) forms. The two Gauche conformers were estimated to be higher in energy, by ca. 1.75 kJ mol−1, than the most stable Trans form. The signatures of all three conformers were found to be present in the experimental low-temperature matrix spectra with the T form dominating in diluted matrices. The conformational ratio was found to shift in favor of the G+/G− forms upon annealing of the matrices as well as in the neat α-terpinene liquid. UV−C (λ > 235 nm) irradiation of matrix-isolated α-terpinene led to its isomerization into an open-ring species, which is produced in the Z configuration and in the conformations that require the smallest structural rearrangements of both the reagent and matrix
Molecular Characterization of a PU.1 Transcription Complex Formed on the IL-1β Proximal Promoter.
Abstract
The gene coding for the pro-inflammatory cytokine IL-1β is induced at the transcription level in differentiating macrophages and in stress response. Interestingly, PU.1 and C/EBPβ, two transcription factors implicated in IL-1β gene expression are not induced by stress exposure, while c-Jun is strongly induced. Strikingly, this upregulation of c-Jun is required for IL-1β induction, as cells expressing a c-Jun antisense construct fail to respond to stress exposure. We have mapped the induction of IL-1β gene expression to its proximal promoter and show that it is mediated by the transcriptional synergy between C/EBPβ, c-Jun and PU.1 via specific DNA binding sites for C/EBPβ and PU.1 only. To elucidate how PU.1 and C/EBPβ cooperate with c-Jun at the molecular level, we have optimized a DNA binding assay based on IL-1β promoter fragments immobilized on beads to isolate protein complexes from nuclear extracts, which were subsequently eluted and identified by Western blotting. We show that PU.1 or C/EBPβ alone directly bind this promoter fragment via specific sequences while purified recombinant c-Jun fails to do so. However, the presence of either PU.1 or C/EBPβ on the promoter allows for a recruitment of c-Jun to the DNA template, mediated by direct protein-protein interaction. Interestingly, the leucine zipper domain of c-Jun is essential for its interaction with C/EBPβ while dispensable for PU.1 interaction in vitro whereas its basic domain is required for both interactions. Furthermore, we show that PU.1 and C/EBPβ cooperatively bind the IL-1β promoter, resulting in a synergistic recruitment of c-Jun. Finally, we show that the strength of interaction of c-Jun mutants with PU.1 or C/EBPβ determine the strength of transcription output and c-Jun mutants that fail to associate with either PU.1 or C/EBPβ are transcriptionally inactive. In contrast, c-Jun mutants exhibiting increased homodimerization are more active that the wild type protein. Taken together, our data suggest that c-Jun homodimers can be targeted to the IL-1β promoter in the absence of a specific DNA binding element, and conclude that PU.1 and C/EBPβ are specifically tethered to the IL-1β promoter while c-Jun cooperatively binds these proteins and acts as a transcriptional co-activator. We propose a mechanism based on an initial binding of PU.1 and C/EBPβ to the IL-1β promoter followed by a cooperative recruitment of c-Jun, resulting in transcriptional synergy and IL-1β gene expression in stress response.</jats:p
Increased Pain Sensitivity in Chronic Pain Subjects on Opioid Therapy: A Cross-Sectional Study Using Quantitative Sensory Testing
Abstract LB194: Discovery and characterization of a mutant selective PI3KαH1047Xinhibitor with a best-in-class profile
Abstract
Oncogenic PIK3CA mutations are found in 14% of all cancers and most frequently occur at amino acids E542/E545 and H1047, involving the helical and kinase domains, respectively (Zhang 2017). Alpelisib is a PI3Kα isoform-selective, orthosteric kinase inhibitor, having equivalent activity on wild-type (wt) and mutant (mt) forms and was approved to treat PI3Kα mt, HR+/HER2- breast cancer in combination with fulvestrant, nearly doubling progression-free survival (Andre 2019). Hyperglycemia with insulin resistance is an on-target result of wt PI3Kα inhibition, leading to frequent alpelisib dose reductions, interruptions, and discontinuations. H1047X is the most common PIK3CA alteration, found in ~14% of all breast cancer patients (Martínez-Sáez 2020). We considered that selectively targeting this mutant could improve patient outcomes by sparing metabolic dysfunction related to wt inhibition. We have validated this therapeutic concept preclinically with the discovery of ST-814, an allosteric, CNS-penetrant, mutant selective PI3KαH1047X inhibitor, displaying excellent drug-like properties. ST-814 was 14-fold selective for PI3KαH1047R vs PI3Kαwt in biochemical assays (IC50 11 vs 146 nM) with exquisite isoform and kinome selectivity. Cell-based activity and selectivity were characterized in T47D (PI3KαH1047R) and SKBR3 (PI3KαWT) tumor cells grown in 10% FBS, with 8-fold mut-selectivity observed in target engagement (pAKT EC50 38 vs 304 nM) and 11-fold selectivity in viability (GI50 153 vs 1683 nM). ST-814 has robust anti-tumor activity in PI3KαH1047X in xenografts, with efficacy similar or superior to alpelisib dosed at 50 mg/kg (Table 1). To achieve this level of mouse efficacy, alpelisib exposure exceeded that in patients &gt;200% (mouse vs human AUC0-24, 74,000 vs 33,224 ng*hr/mL). As such, repeat dosing of alpelisib at 50 mg/kg, caused profound elevations in serum insulin 1 hr post-dose (*p&lt;0.01), whereas ST-814 showed no significant difference (Table 1). The metabolic consequences of repeated alpelisib (50 mg/kg) and ST-814 (100 mg/kg) dosing was further characterized in an insulin tolerance test. Insulin-mediated glucose clearance (AUC0-4) was significantly impaired by alpelisib (p&lt;0.01, one-way ANOVA), but not by ST-814. These data support the potential of molecules like ST-814 to improve outcomes in patients harboring H1047X mut tumors. A clinical candidate from this program is currently in IND enabling studies.
Table 1. CAL33 H1047R Oral Sq Cell Carcinoma Xenograft Alpelisib TGI% 50 mg/kg ST-814 TGI% 100 mg/kg Alpelisib ΔInsulin ng/mL ST-814 ΔInsulin ng/mL 79% 82% 4.42* 0.40
Citation Format: Leonard Buckbinder, David J. St. Jean, Trang Tieu, Weixue Wang, Gregory Kryukov, Philip Jonsson, Jacob Alltucker, Samantha Manimala, Brendon Ladd, Angel Guzman-Perez, Darrin Stuart. Discovery and characterization of a mutant selective PI3KαH1047Xinhibitor with a best-in-class profile [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB194.</jats:p
Abstract P4-07-04: STX-478, a mutant-selective PI3Kα H1047X inhibitor clinical candidate with a best-in-class profile: Pharmacology and therapeutic activity as monotherapy and in combination in breast cancer xenograft models
Abstract
PI3Kα is highly mutated in cancer resulting in hyperactivation of lipid kinase activity and downstream AKT signaling. H1047 is the most common site of oncogenic mutation and occurs in ~14% of all breast cancers. Initial therapeutic benefit of targeting PI3Kα was established with alpelisib, an alpha-selective PI3K inhibitor that is equipotent against wild-type and mutant forms. However, wild-type PI3Kα inhibition results in frequent dose-limiting toxicities including hyperglycemia, restricting the full potential of this drug. Selective targeting of H1047X-mutant PI3Kα is expected to both improve anti-tumor activity and reduce toxicity. STX-478 is an allosteric, CNS-penetrant, selective PI3Kα H1047X inhibitor, having excellent drug-like properties and exceptional kinome selectivity. STX-478 demonstrated minimal inhibition of CYP enzymes in vitro, supporting the potential for combinations with a wide range of therapeutics in breast cancer and a variety of other tumor types. STX-478 selectivity extended to the inhibition of other activating kinase domain mutations in biochemical assays. In a diverse panel of PI3Kα H1047X mutant cell lines, STX-478 selectively reduced the cellular levels of pAKT (S473) with a strong correlation between pAKT inhibition and cell viability (R = 0.8). In a high-throughput viability screen of 467 cancer cell lines, the presence of PIK3CA H1047X and other kinase domain mutations were the single strongest predictor of STX-478 sensitivity with potency superior to alpelisib. STX-478 also selectively inhibited the proliferation of cell lines with PI3Kα helical domain mutations, potentially due to the selective dependency of these cells on mutant PI3Kα. When combined with fulvestrant, lapatinib, or abemaciclib, STX-478 demonstrated synergistic anti-proliferative activity in cell lines with relevant ER/HER2 status. Unlike alpelisib, STX-478 did not impair glucose metabolism or cause insulin resistance at efficacious doses. In the T47D (PI3Kα H1047R) breast cancer model, STX-478 (100 mg/kg) monotherapy caused tumor regression whereas alpelisib caused only stasis. STX-478 combination with fulvestrant was well-tolerated, with more consistent and deeper tumor regression. Similar results were observed in a PI3Kα H1047R mutant ER+/HER2- PDX model, where fulvestrant monotherapy showed minimal activity, while combination with STX-478 yielded tumor regressions. In an ER+/HER2+ PDX model (PI3Kα H1047R/R108H), palbociclib and STX-478 (100 mg/kg) monotherapy resulted in similar efficacy while the combination was well tolerated and yielded tumor regression. Together these data indicate robust STX-478 monotherapy activity that was well tolerated and improved when dosed in combination with fulvestrant or CDK4/6 inhibitors. Finally, we investigated the effect of STX-478 treatment in an ER+ PDX model carrying a helical domain mutation. STX-478 treatment resulted in tumor growth inhibition at doses that did not result in metabolic dysfunction, suggesting that STX-478 may also be efficacious in treating PIK3CA mutant tumors with helical domain mutations. In summary, STX-478 efficacy was superior to alpelisib at a dose level that exceeds the clinically relevant exposure in mice without causing metabolic dysfunction. STX- 478 has a predicted low human dose, CNS exposure, low risk of DDI, and a predicted long half-life with minimal variation in peak-to-trough plasma concentrations which further supports a favorable therapeutic index. STX-478 has the potential to provide a best-in-class profile to improve outcomes in patients harboring tumors with prevalent PI3Kα H1047X mutations as well as other kinase and helical domain mutant tumors. The significant CNS exposure of STX-478 is expected to enable this treatment for patients with brain tumors and brain metastases not afforded by existing options. STX-478 is currently in IND enabling studies and is expected to enter human clinical trials in 2023.
Citation Format: Leonard Buckbinder, David J. St. Jean, Brendon Ladd, Trang Tieu, Philip Jonsson, Jacob Alltucker, Samantha Manimala, Weixue Wang, Angel Guzman-Perez, Darrin D. Stuart, Gregory Dowdell. STX-478, a mutant-selective PI3Kα H1047X inhibitor clinical candidate with a best-in-class profile: Pharmacology and therapeutic activity as monotherapy and in combination in breast cancer xenograft models [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-04.</jats:p
Problem list completeness in electronic health records: A multi-site study and assessment of success factors.
OBJECTIVE: To assess problem list completeness using an objective measure across a range of sites, and to identify success factors for problem list completeness. METHODS: We conducted a retrospective analysis of electronic health record data and interviews at ten healthcare organizations within the United States, United Kingdom, and Argentina who use a variety of electronic health record systems: four self-developed and six commercial. At each site, we assessed the proportion of patients who have diabetes recorded on their problem list out of all patients with a hemoglobin A1c elevation >= 7.0%, which is diagnostic of diabetes. We then conducted interviews with informatics leaders at the four highest performing sites to determine factors associated with success. Finally, we surveyed all the sites about common practices implemented at the top performing sites to determine whether there was an association between problem list management practices and problem list completeness. RESULTS: Problem list completeness across the ten sites ranged from 60.2% to 99.4%, with a mean of 78.2%. Financial incentives, problem-oriented charting, gap reporting, shared responsibility, links to billing codes, and organizational culture were identified as success factors at the four hospitals with problem list completeness at or near 90.0%. DISCUSSION: Incomplete problem lists represent a global data integrity problem that could compromise quality of care and put patients at risk. There was a wide range of problem list completeness across the healthcare facilities. Nevertheless, some facilities have achieved high levels of problem list completeness, and it is important to better understand the factors that contribute to success to improve patient safety. CONCLUSION: Problem list completeness varies substantially across healthcare facilities. In our review of EHR systems at ten healthcare facilities, we identified six success factors which may be useful for healthcare organizations seeking to improve the quality of their problem list documentation: financial incentives, problem oriented charting, gap reporting, shared responsibility, links to billing codes, and organizational culture
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