Modeling CLV:A test of competing models in the insurance industry

Customer Lifetime Value (CLV) is one of the key metrics in marketing and is considered an important segmentation base. This paper studies the capabilities of a range of models to predict CLV in the insurance industry. The simplest models can be constructed at the customer relationship level, i.e. aggregated across all services. The more complex models focus on the individual services, paying explicit attention to cross buying, but also retention. The models build on a plethora of approaches used in the existing literature and include a status quo model, a Tobit II model, univariate and multivariate choice models, and duration models. For all models, CLV for each customer is computed for a four-year time horizon. We find that the simple models perform well. The more complex models are expected to better capture the richness of relationship development. Surprisingly, this does not lead to substantially better CLV predictions

Mass spectrometric quantification of urinary 6-sulfatoxymelatonin:age-dependent excretion and biological variation

Objectives: Regulators of circadian rhythm, including melatonin, influence fundamental biological processes. Measuring the melatonin metabolite 6-sulfatoxymelatonin in urine can estimate melatonin production. 6-sulfatoxymelatonin is mainly analyzed by immunoassays, but these methods are hampered by cross-reactivity and poor reproducibility when used to analyze small molecules. Therefore, we validated a high-throughput liquid chromatography with tandem mass spectrometry (LC-MS/MS) method to quantify 6-sulfatoxymelatonin in urine. We evaluated age-dependent 24-h excretion of 6-sulfatoxymelatonin into urine and the biological variation of urinary excretion in healthy individuals. Methods: The online solid phase extraction method combined with LC-MS/MS was validated according to international guidelines, and used to measure the excretion of 6-sulfatoxymelatonin into urine of 240 healthy individuals. Biological variation of 6-sulfatoxymelatonin excretion was examined in 10 healthy individuals. Results: Urinary 6-sulfatoxymelatonin results were well within the validation criteria (interassay coefficient of variation: Conclusions: This MS-based method enables straightforward, reproducible, and sensitive quantification of 6-sulfatoxymelatonin in urine. Urinary 6-sulfatoxymelatonin levels decreased with age. Biological variation of 6-sulfatoxymelatonin excretion into urine was high between subjects and lower within subjects, indicating that repeated measurements of 6-sulfatoxymelatonin in 24-h urine are needed in future studies

Use of selective serotonin reuptake inhibitors is associated with very low plasma free serotonin concentrations in humans

Background: Selective serotonin reuptake inhibitors (SSRIs) block the serotonin transporter on neurons, but also on platelets, thus decreasing platelet serotonin concentrations in users of SSRIs. Data on plasma free serotonin concentrations in SSRI users is lacking, while plasma free serotonin is available for receptor binding and plays a role in several pathophysiological processes We therefore measured the plasma free and platelet serotonin concentrations in users of SSRIs and age-matched healthy controls, and we analyzed plasma concentrations of the serotonin precursor tryptophan and serotonin metabolite 5-hydroxyindoleamineacetic acid (5-HIAA). Methods: For this cross-sectional single center case control study, participants were recruited at the departments of Psychiatry and General Medicine. High performance liquid chromatography combined with tandem mass spectrometry (LC-MS/MS) was used to measure plasma free and platelet serotonin, plasma tryptophan and 5-HIAA concentrations. Pre-analytical conditions were optimized by careful blood collection, rapid sample handling, high speed centrifugation, drug and diet restrictions, and age-matched controls. Results: In 64 SSRI users, median concentrations of plasma free and platelet serotonin were 10-fold and 14-fold lower, respectively, than in 64 matched controls. Patients using higher dose SSRIs or those with higher affinity for the serotonin transporter had lower plasma free and platelet serotonin concentrations. Compared to controls, SSRI users had similar median plasma tryptophan concentrations, but slightly higher plasma 5-HIAA concentrations. Conclusion: SSRI users have low platelet serotonin and low plasma free serotonin. This could not be explained by lower concentrations of its precursor tryptophan, and only partially by increased breakdown to 5-HIAA

Functional siRNA Delivery by Extracellular Vesicle-Liposome Hybrid Nanoparticles

The therapeutic use of RNA interference is limited by the inability of siRNA molecules to reach their site of action, the cytosol of target cells. Lipid nanoparticles, including liposomes, are commonly employed as siRNA carrier systems to overcome this hurdle, although their widespread use remains limited due to a lack of delivery efficiency. More recently, nature's own carriers of RNA, extracellular vesicles (EVs), are increasingly being considered as alternative siRNA delivery vehicles due to their intrinsic properties. However, they are difficult to load with exogenous cargo. Here, EV-liposome hybrid nanoparticles (hybrids) are prepared and evaluated as an alternative delivery system combining properties of both liposomes and EVs. It is shown that hybrids are spherical particles encapsulating siRNA, contain EV-surface makers, and functionally deliver siRNA to different cell types. The functional behavior of hybrids, in terms of cellular uptake, toxicity, and gene-silencing efficacy, is altered as compared to liposomes and varies among recipient cell types. Moreover, hybrids produced with cardiac progenitor cell (CPC) derived-EVs retain functional properties attributed to CPC-EVs such as activation of endothelial signaling and migration. To conclude, hybrids combine benefits of both synthetic and biological drug delivery systems and might serve as future therapeutic carriers of siRNA

Treatment and overall survival of four types of non-metastatic periampullary cancer:nationwide population-based cohort study

Background: Periampullary adenocarcinoma consists of pancreatic adenocarcinoma (PDAC), distal cholangiocarcinoma (DC), ampullary cancer (AC), and duodenal adenocarcinoma (DA). The aim of this study was to assess treatment modalities and overall survival by tumor origin. Methods: Patients diagnosed with non-metastatic periampullary cancer in 2012–2018 were identified from the Netherlands Cancer Registry. OS was studied with Kaplan–Meier analysis and multivariable Cox regression analyses, stratified by origin. Results: Among the 8758 patients included, 68% had PDAC, 13% DC, 12% AC, and 7% DA. Resection was performed in 35% of PDAC, 56% of DC, 70% of AC, and 59% of DA. Neoadjuvant and/or adjuvant therapy was administered in 22% of PDAC, 7% of DC, 7% of AC, and 12% of DA. Three-year OS was highest for AC (37%) and DA (34%), followed by DC (21%) and PDAC (11%). Adjuvant therapy was associated with improved OS among PDAC (HR = 0.62; 95% CI 0.55–0.69) and DC (HR = 0.69; 95% CI 0.48–0.98), but not AC (HR = 0.87; 95% CI 0.62–1.22) and DA (HR = 0.85; 95% CI 0.48–1.50). Conclusion: This retrospective study identified considerable differences in treatment modalities and OS between the four periampullary cancer origins in daily clinical practice. An improved OS after adjuvant chemotherapy could not be demonstrated in patients with AC and DA

Pancreatic resection in the pediatric, adolescent and young adult population:nationwide analysis on complications

Background: The aim of this study was to determine pancreatic surgery specific short- and long-term complications of pediatric, adolescent and young adult (PAYA) patients who underwent pancreatic resection, as compared to a comparator cohort of adults. Methods: A nationwide retrospective cohort study was performed in PAYA patients who underwent pancreatic resection between 2007 and 2016. PAYA was defined as all patients <40 years at time of surgery. Pancreatic surgery-specific complications were assessed according to international definitions and textbook outcome was determined. Results: A total of 230 patients were included in the PAYA cohort (112 distal pancreatectomies, 99 pancreatoduodenectomies), and 2526 patients in the comparator cohort. For pancreatoduodenectomy, severe morbidity (29.3% vs. 28.6%; P = 0.881), in-hospital mortality (1% vs. 4%; P = 0.179) and textbook outcome (62% vs. 58%; P = 0.572) were comparable between the PAYA and the comparator cohort. These outcomes were also similar for distal pancreatectomy. After pancreatoduodenectomy, new-onset diabetes mellitus (8% vs. 16%) and exocrine pancreatic insufficiency (27% vs. 73%) were lower in the PAYA cohort when compared to adult literature. Conclusion: Pancreatic surgery-specific complications were comparable with patients ≥40 years. Development of endocrine and exocrine insufficiency in PAYA patients who underwent pancreatoduodenectomy, however, was substantially lower compared to adult literature

Occupational exposure to gases/fumes and mineral dust affect DNA methylation levels of genes regulating expression

Many workers are daily exposed to occupational agents like gases/fumes, mineral dust or biological dust, which could induce adverse health effects. Epigenetic mechanisms, such as DNA methylation, have been suggested to play a role. We therefore aimed to identify differentially methylated regions (DMRs) upon occupational exposures in never-smokers and investigated if these DMRs associated with gene expression levels. To determine the effects of occupational exposures independent of smoking, 903 never-smokers of the LifeLines cohort study were included. We performed three genome-wide methylation analyses (Illumina 450 K), one per occupational exposure being gases/fumes, mineral dust and biological dust, using robust linear regression adjusted for appropriate confounders. DMRs were identified using comb-p in Python. Results were validated in the Rotterdam Study (233 never-smokers) and methylation-expression associations were assessed using Biobank-based Integrative Omics Study data (n = 2802). Of the total 21 significant DMRs, 14 DMRs were associated with gases/fumes and 7 with mineral dust. Three of these DMRs were associated with both exposures (RPLP1 and LINC02169 (2x)) and 11 DMRs were located within transcript start sites of gene expression regulating genes. We replicated two DMRs with gases/fumes (VTRNA2-1 and GNAS) and one with mineral dust (CCDC144NL). In addition, nine gases/fumes DMRs and six mineral dust DMRs significantly associated with gene expression levels. Our data suggest that occupational exposures may induce differential methylation of gene expression regulating genes and thereby may induce adverse health effects. Given the millions of workers that are exposed daily to occupational exposures, further studies on this epigenetic mechanism and health outcomes are warranted

Study Protocol PROMETHEUS:Prospective Multicenter Study to Evaluate the Correlation Between Safety Margin and Local Recurrence After Thermal Ablation Using Image Co-registration in Patients with Hepatocellular Carcinoma

Purpose: The primary objective is to determine the minimal ablation margin required to achieve a local recurrence rate of 18 years with Barcelona Clinic Liver Cancer stage 0/A hepatocellular carcinoma (or B with a maximum of two lesions < 5 cm each) are eligible. Patients will undergo dual-phase contrast-enhanced computed tomography directly before and after ablation. Ablation margins will be quantitatively assessed using co-registration software, blinding assessors (i.e. two experienced radiologists) for outcome. Presence and location of recurrence are evaluated independently on follow-up scans by two other experienced radiologists, blinded for the quantitative margin analysis. A sample size of 189 tumors (~ 145 patients) is required to show with 80% power that the risk of local recurrence is confidently below 10%. A two-sided binomial z-test will be used to test the null hypothesis that the local recurrence rate is ≥ 10% for patients with a minimal ablation margin ≥ 2 mm. Logistic regression will be used to find the relationship between minimal ablation margins and local recurrence. Kaplan–Meier estimates are used to assess local and overall recurrence, disease-free and overall survival. Discussion: It is expected that this study will result in a clear understanding of the correlation between ablation margins and local recurrence. Using co-registration software in future patients undergoing ablation for hepatocellular carcinoma may improve intraprocedural evaluation of technical success. Trial registration The Netherlands Trial Register (NL9713), https://www.trialregister.nl/trial/9713