Fragmentation of care in breast cancer: greater than the sum of its parts.

INTRODUCTION: Fragmentation of care (FC, the receipt of care at > 1 institution) has been shown to negatively impact cancer outcomes. Given the multimodal nature of breast cancer treatment, we sought to identify factors associated with FC and its effects on survival of breast cancer patients. METHODS: A retrospective analysis was performed of surgically treated, stage I-III breast cancer patients in the 2004-2020 National Cancer Database, excluding neoadjuvant therapy recipients. Patients were stratified into two groups: FC or non-FC care. Treatment delay was defined as definitive surgery > 60 days after diagnosis. Multivariable logistic regression was performed to identify factors predictive of FC, and survival was compared using Kaplan-Meier and multivariable Cox proportional hazards methods. RESULTS: Of the 531,644 patients identified, 340,297 (64.0%) received FC. After adjustment, FC (OR 1.27, 95% CI 1.25-1.29) was independently associated with treatment delay. Factors predictive of FC included Hispanic ethnicity (OR 1.04, 95% CI: 1.01-1.07), treatment at comprehensive community cancer programs (OR 1.06, 95% CI: 1.03-1.08) and integrated network cancer programs (OR 1.55, 95% CI: 1.51-1.59), AJCC stage II (OR 1.06, 95% CI 1.05-1.07) and stage III tumors (OR 1.06, 95% CI: 1.02-1.10), and HR + /HER2 + tumors (OR 1.05, 95% CI: 1.02-1.07). Treatment delay was independently associated with increased risk of mortality (HR 1.23, 95% CI 1.20-1.26), whereas FC (HR 0.87, 95% CI 0.86-0.88) showed survival benefit. CONCLUSIONS: While treatment delay negatively impacts survival in breast cancer patients, our findings suggest FC could be a marker for multispecialty care that may mitigate some of these effects.

Oncologic outcomes and survival of modern surgical approaches for gastric gastrointestinal stromal tumor (GIST).

BACKGROUND: Studies have demonstrated comparable outcomes between laparoscopic and open resection of gastrointestinal stromal tumor (GIST). We sought to compare outcomes among robotic, laparoscopic, and open resection of gastric GIST in the era of expanding minimally invasive surgery. METHODS: A retrospective analysis was performed of adult patients with gastric GIST undergoing definitive surgery using the National Cancer Database from 2010 to 2020, excluding cases converted to open. Patients were stratified into minimally invasive surgery (MIS), (combined robotic (R) and laparoscopic (L)), and open (O). Hospital length of stay (LOS), 30-day mortality, 90-day mortality, and margin status were assessed. Subgroup analysis was performed to evaluate outcomes between R and L cohorts. Entropy balancing was used to adjust for intergroup differences. Kaplan-Meier survival estimates were used to compare unadjusted 5-year survival. RESULTS: Of the 15,022 patients (R = 10.4%, L = 44.3%, O = 45.3%), 63.2% were stage I and 70.6% underwent partial gastrectomy. MIS approach was associated with shorter hospital LOS (ß: - 2.58; 95% CI: - 2.82 to - 2.33) and lower odds of 30-day (OR 0.45; 95% CI: 0.30-0.68) and 90-day mortality (OR 0.54; 95% CI: 0.39-0.74) compared to O. Likelihood of R0 resection similar between groups (OR 1.00; 95% CI: 0.88-1.14). Hospital LOS (ß: + 0.25; 95% CI: - 0.14-0.64), odds of 30-day (OR 0.99; 95% CI: 0.40-2.46) and 90-day mortality (OR 0.89; 95% CI: 0.47-1.70), and rate of R0 resection (OR 1.02; 95% CI: 0.82-1.27) were comparable between R and L cohorts. Compared to O, MIS approach was associated with improved 5-year OS (log rank p < 0.001). Overall survival was not significantly different between R and L (log rank p = 0.44). CONCLUSION: These findings suggest that MIS approach may be considered for resection of gastric GIST in select patients. Among patients receiving an MIS approach, the robotic technique can be considered an oncologically safe alternative to laparoscopic surgery.

High-Throughput Screening of Streptavidin-Binding Proteins in Self-Assembled Solid Films for Directed Evolution of Materials.

Evolution has shaped the development of proteins with an incredible diversity of properties. Incorporating proteins into materials is desirable for applications including biosensing; however, high-throughput selection techniques for screening protein libraries in materials contexts is lacking. In this work, a high-throughput platform to assess the binding affinity for ordered sensing proteins was established. A library of fusion proteins, consisting of an elastin-like polypeptide block, one of 22 variants of rcSso7d, and a coiled-coil order-directing sequence, was generated. All selected variants had high binding in films, likely due to the similarity of the assay to magnetic bead sorting used for initial selection, while solution binding was more variable. From these results, both the assembly of the fusion proteins in their operating state and the functionality of the binding protein are key factors in the biosensing performance. Thus, the integration of directed evolution with assembled systems is necessary to the design of better materials.

Robotic major and minor hepatectomy: critical appraisal of learning curve and its impact on outcomes.

BACKGROUND: Robotic hepatectomy has gained increasing acceptance across the US. Although the robotic approach offers significant technical advantages, it is still bound by the individual surgeon's learning curve. Proficiency in this approach should theoretically lead to improved peri-operative outcomes. METHODS: Between 2017 and 2020, data on 148 consecutive robotic hepatectomies performed by a single surgeon was retrospectively analyzed. Using cumulative sum (CUSUM) method, intraoperative blood loss (EBL) and operative time were used to assess learning curves for robotic major (n = 58) and minor (n = 90) hepatectomy patients. Perioperative outcomes were compared in regards with proficiency. RESULTS: Proficiency for robotic major and minor hepatectomy was achieved after 22 cases and 34 cases, respectively. No significant differences were observed in patient demographics or tumor characteristics. For robotic major hepatectomy, when compared to early experience, proficiency was associated with a significant improvement in mean EBL (242 mL vs 118 mL, p = 0.0004), operative time (330 min vs 247 min, p = 0.0002), decreased overall complication rate (23% vs 3%, p = 0.039), and length of hospital stay (5.7 days vs 4.1 days, p = 0.004). No difference in conversion rate, mortality or 30 day readmission was seen. For robotic minor hepatectomy, proficiency was associated with significantly decreased mean EBL (115 mL vs 54 mL, p = 0.005), operative time (168 vs 125 min, p = 0.014), and length of hospital stay (2.8 days vs 2.1 days, p = 0.021). No difference was observed in conversion rate, overall complications, mortality or 30 day readmission. CONCLUSION: In the modern era, robotic hepatectomy offers a safe approach with excellent perioperative outcomes. Post learning curve proficiency is associated with significant improvements in perioperative outcomes in both major and minor hepatectomy. Results from our study can serve as a guide to surgeons and programs looking to adopt this technique.

Exponential Amplification Using Photoredox Autocatalysis.

Exponential molecular amplification such as the polymerase chain reaction is a powerful tool that allows ultrasensitive biodetection. Here, we report a new exponential amplification strategy based on photoredox autocatalysis, where eosin Y, a photocatalyst, amplifies itself by activating a nonfluorescent eosin Y derivative (EYH3-) under green light. The deactivated photocatalyst is stable and rapidly activated under low-intensity light, making the eosin Y amplification suitable for resource-limited settings. Through steady-state kinetic studies and reaction modeling, we found that EYH3- is either oxidized to eosin Y via one-electron oxidation by triplet eosin Y and subsequent 1e-/H+ transfer, or activated by singlet oxygen with the risk of degradation. By reducing the rate of the EYH3- degradation, we successfully improved EYH3--to-eosin Y recovery, achieving efficient autocatalytic eosin Y amplification. Additionally, to demonstrate its flexibility in output signals, we coupled the eosin Y amplification with photoinduced chromogenic polymerization, enabling sensitive visual detection of analytes. Finally, we applied the exponential amplification methods in developing bioassays for detection of biomarkers including SARS-CoV-2 nucleocapsid protein, an antigen used in the diagnosis of COVID-19.

Kinetic modeling of H2O2 dynamics in the mitochondria of HeLa cells.

Hydrogen peroxide (H2O2) promotes a range of phenotypes depending on its intracellular concentration and dosing kinetics, including cell death. While this qualitative relationship has been well established, the quantitative and mechanistic aspects of H2O2 signaling are still being elucidated. Mitochondria, a putative source of intracellular H2O2, have recently been demonstrated to be particularly vulnerable to localized H2O2 perturbations, eliciting a dramatic cell death response in comparison to similar cytosolic perturbations. We sought to improve our dynamic and mechanistic understanding of the mitochondrial H2O2 reaction network in HeLa cells by creating a kinetic model of this system and using it to explore basal and perturbed conditions. The model uses the most current quantitative proteomic and kinetic data available to predict reaction rates and steady-state concentrations of H2O2 and its reaction partners within individual mitochondria. Time scales ranging from milliseconds to one hour were simulated. We predict that basal, steady-state mitochondrial H2O2 will be in the low nM range (2-4 nM) and will be inversely dependent on the total pool of peroxiredoxin-3 (Prx3). Neglecting efflux of H2O2 to the cytosol, the mitochondrial reaction network is expected to control perturbations well up to H2O2 generation rates ~50 µM/s (0.25 nmol/mg-protein/s), above which point the Prx3 system would be expected to collapse. Comparison of these results with redox Western blots of Prx3 and Prx2 oxidation states demonstrated reasonable trend agreement at short times (≤ 15 min) for a range of experimentally perturbed H2O2 generation rates. At longer times, substantial efflux of H2O2 from the mitochondria to the cytosol was evidenced by peroxiredoxin-2 (Prx2) oxidation, and Prx3 collapse was not observed. A refined model using Monte Carlo parameter sampling was used to explore rates of H2O2 efflux that could reconcile model predictions of Prx3 oxidation states with the experimental observations.

Should 'Omics' education be a part of allied health profession curricula?

Sequencing of human genome followed by monumental progress in omics sciences within last two decades has made personalized nutrition for better health is a reality for near future. The complexity of underlying science in making personalized nutrition recommendation has led to the need for training of health care providers. The International Society of Nutrigenetics/Nutrigenomics (ISNN) has mission to increase the understanding among both professionals and the general public of the role of genetic variation and nutrients in gene expression. To bring this mission to fruition, we need trained healthcare professionals ready to educate public. With this in mind, we have surveyed allied health students for their omics knowledge, desire to learn more and their perception of the need of omics education. The results show a need for training in omics in all allied health disciplines and desire of the students to learn more.

Functional comparison of paper-based immunoassays based on antibodies and engineered binding proteins.

Binding protein scaffolds, such as rcSso7d, have been investigated for use in diagnostic tests; however, the functional performance of rcSso7d has not yet been studied in comparison to antibodies. Here, we assessed the analyte-binding capabilities of rcSso7d and antibodies on cellulose with samples in buffer and 100% human serum.

Design Principles for Enhancing Sensitivity in Paper-Based Diagnostics via Large-Volume Processing.

In this work, we characterize the impact of large-volume processing upon the analytical sensitivity of flow-through paper-based immunoassays. Larger sample volumes feature greater molar quantities of available analyte, but the assay design principles which would enable the rapid collection of this dilute target are ill-defined. We developed a finite-element model to explore the operating conditions under which processing large sample volumes via pressure-driven convective flow would yield an improved binding signal. Our simulation results underscore the importance of establishing a high local concentration of the analyte-binding species within the porous substrate. This elevated abundance serves to enhance the binding kinetics, matching the time scale of target capture to the period during which the sample is in contact with the test zone (i.e., the effective residence time). These findings were experimentally validated using the rcSso7d-cellulose-binding domain (CBD) fusion construct, a bifunctional binding protein which adsorbs to cellulose in high abundance. As predicted by our modeling efforts, the local concentration achieved using the rcSso7d-CBD species is uniquely enabling for sensitivity enhancement through large-volume processing. The rapid analyte depletion which occurs at this high surface density also permits the processing of large sample volumes within practical time scales and flow regimes. Using these findings, we present guidance for the optimal means of processing large sample volumes for enhanced assay sensitivity.

Improved Ordering in Low Molecular Weight Protein-Polymer Conjugates Through Oligomerization of the Protein Block.

The self-assembly of protein-polymer conjugates incorporating oligomers of a small, engineered high-affinity binding protein, rcSso7d.SA, is studied to determine the effect of protein oligomerization on nanoscale ordering. Oligomerization enables a systematic increase in the protein molar mass without changing its overall folded structure, leading to a higher driving force for self-assembly into well-ordered structures. Though conjugates of monomeric rcSso7d.SA are found to only exist in disordered states, oligomers of this protein linked to a poly( N-isopropylacrylamide) (PNIPAM) block self-assemble into lamellar nanostructures. Conjugates of trimeric and tetrameric rcSso7d.SA are observed to produce the strongest ordering in concentrated solution, displaying birefringent lamellae at concentrations as low as 40 wt %. In highly concentrated solution, the oligomeric rcSso7d.SA-PNIPAM block copolymers exhibit ordering and domain spacing trends atypical from that of most block copolymers. Fluorescent binding assays indicate that oligomerized protein blocks retain binding functionality and exhibit limits of detection up to three times lower than that of surface-immobilized protein sensors. Therefore, oligomerization of the protein block in these block copolymers serves as an effective method to improve both nanoscale ordering and biosensing capabilities.

A Method for Designing Instrument-Free Quantitative Immunoassays.

Colorimetric readouts are widely used in point-of-care diagnostic immunoassays to indicate either the presence or the absence of an analyte. For a variety of reasons, it is more difficult to quantify rather than simply detect an analyte using a colorimetric test. We report a method for designing, with minimal iteration, a quantitative immunoassay that can be interpreted objectively by a simple count of number of spots visible to the unaided eye. We combined a method called polymerization-based amplification (PBA) with a series of microscale features containing a decreasing surface density of capture molecules, and the central focus of the study is understanding how the choice of surface densities impacts performance. Using a model pair of antibodies, we have shown that our design approach does not depend on measurement of equilibrium and kinetic binding parameters and can provide a dynamic working range of 3 orders of magnitude (70 pM to 70 nM) for visual quantification.

Portable, Constriction-Expansion Blood Plasma Separation and Polymerization-Based Malaria Detection.

A portable, microfluidic blood plasma separation device is presented featuring a constriction-expansion design, which produces 100.0% purity for undiluted blood at 9% yield. This level of purity represents an improvement of at least 1 order of magnitude with increased yield compared to that achieved previously using passive separation. The system features high flow rates, 5-30 µL/min plasma collection, with minimal clogging and biofouling. The simple, portable blood plasma separation design is hand-driven and can easily be incorporated with microfluidic or laboratory scale diagnostic assays. The separation system was applied to a paper-based diagnostic test for malaria that produced an amplified color change in the presence of Plasmodium falciparum histidine-rich protein 2 at a concentration well below clinical relevancy for undiluted whole blood.

Interpreting Heterogeneity in Response of Cells Expressing a Fluorescent Hydrogen Peroxide Biosensor.

Fluorescent, genetically encoded sensors of hydrogen peroxide have enabled visualization of perturbations to the intracellular level of this signaling molecule with subcellular and temporal resolution. Ratiometric sensors hold the additional promise of meaningful quantification of intracellular hydrogen peroxide levels as a function of time, a longstanding goal in the field of redox signaling. To date, studies that have connected the magnitudes of observed ratios with peroxide concentrations have either examined suspensions of cells or small numbers of adherent cells (∼10). In this work, we examined the response of all cells in several microscopic fields of view to an identical perturbation and observed a striking degree of heterogeneity of fluorescence ratios from individual cells. The expression level of the probe and phase within the cell cycle were each examined as potential contributors to the observed heterogeneity. Higher ratiometric responses correlated with greater expression levels of the probe and phase in the cell cycle were also shown to influence the magnitude of response. To aid in the interpretation of experimental observations, we incorporated the reaction of the reduced probe with peroxide and the reactions of the oxidized probe with glutathione and glutaredoxin into a larger kinetic model of peroxide metabolism. The predictions of the kinetic model suggest possible explanations for the experimental observations. This work highlights the importance of a systems-level approach to understanding the output of genetically encoded sensors that function via redox reactions involving thiol and disulfide groups.

The impact of multiplex genetic testing on disease risk perceptions.

This study assessed the effects of multiplex genetic testing on disease risk perceptions among 216 healthy adults. Participants, aged 25-40, were recruited through the Multiplex Initiative, which offered a genetic susceptibility test for eight common diseases. Participants completed baseline telephone and web-based surveys prior to making the testing decision. Three months after the receipt of mailed test results, participants completed a follow-up telephone survey. Risk perceptions for the eight diseases were measured at baseline and follow-up, along with beliefs about genetic causation of those diseases. The main results were: (i) mean risk perceptions were considerably stable from baseline to follow-up; (ii) the best predictors of follow-up risk perceptions were the corresponding baseline perceptions and family history; and (iii) within-individuals, most participants increased or decreased their risk perceptions for specific diseases in concordance with the number of risk markers they carry, their family history and their beliefs about genetic causality of diseases. In conclusion, participants presented a vigilant approach to the interpretation of genetic test results, which provides reassurance with regard to a potential inflation of risk perceptions in the population because of multiplex genetic testing.

Evaluating the sensitivity of hybridization-based epigenotyping using a methyl binding domain protein.

Hypermethylation of CpG islands in gene promoter regions has been shown to be a predictive biomarker for certain diseases. Most current methods for methylation profiling are not well-suited for clinical analysis. Here, we report the development of an inexpensive device and an epigenotyping assay with a format conducive to multiplexed analysis.

Baseline [(123) I]FP-CIT SPECT (DaTSCAN) severity correlates with medication use at 3 years in Parkinson's disease.

BACKGROUND: Presynaptic dopaminergic deficiency on dopamine transporter imaging supports a clinical diagnosis of Parkinson's disease and correlates with the severity of rigidity and bradykinesia. Baseline dopaminergic deficiency predicts clinical severity, but the relationship with subsequent medication use has not been reported. METHODS: A randomly selected cross section of 83 Parkinson's disease (PD) patients who had [(123) I] FP-CIT SPECT at the time of clinical diagnosis was identified. Dopaminergic deficiency was graded 1, 2 or 3 with increasing severity using visual assessment and by semiquantitative analysis of putamen and caudate uptake. Antiparkinson medication usage and clinical severity by Hoehn and Yahr were noted annually to 3 years. RESULTS: In 83 patients (66% male, median age 65.0 years, IQ 55.4-71.8), [(123) I]FP-CIT SPECT was grade 1 in 20 (24%), grade 2 in 53 (64%) and grade 3 in 10 patients (12%). Dopamine transporter uptake ratios were inversely associated with antiparkinson medication usage (r = -0.26, P = 0.0201) and Hoehn Yahr stage (r = -0.32, P = 0.0029) at 3 years from baseline, but there was considerable variation in drug usage in individual patients. At 3 years, patients with grade 1 scans at baseline received a median dose of 325 levodopa equivalent units (LEU) (interquartile range 175-433); grade 2 scan patients 400 LEU (interquartile range 300-635); and grade 3 scan patients 460 LEU (interquartile range 252-658). CONCLUSION: The degree of reduction in presynaptic dopaminergic uptake at baseline is associated with higher antiparkinson drug dosage at follow-up, but the wide variation means that the baseline FP-CIT SPECT does not reliably predict drug use in individual cases.

Balancing the initiation and molecular recognition capabilities of eosin macroinitiators of polymerization-based signal amplification reactions.

Coupling polymerization initiators to molecular recognition events provide the ability to amplify these events and detect them using the formation of a cross-linked polymer as an inexpensive readout that is visible to the unaided eye. The eosin-tertiary amine co-initiation system, activated by visible light, has proven utility in this context when an average of three eosin molecules are coupled to a protein detection reagent. The present work addresses the question of how detection sensitivity is impacted when the number of eosin molecules per binding event increases in the range of two to fifteen. Unlike in other initiation systems, a non-monotonic relationship is observed between the number of initiators per binding event and the observed detection sensitivity.

NADPH composite index analysis quantifies the relationship between compartmentalized NADPH dynamics and growth rates in cancer cells.

NADPH, a highly compartmentalized electron donor in mammalian cells, plays essential roles in cell metabolism. However, little is known about how cytosolic and mitochondrial NADPH dynamics relate to cancer cell growth rates in response to varying nutrient conditions. To address this issue, we present NADPH composite index analysis, which quantifies the relationship between compartmentalized NADPH dynamics and growth rates using genetically encoded NADPH sensors, automated image analysis pipeline, and correlation analysis. Through this analysis, we demonstrated that compartmentalized NADPH dynamics patterns were cancer cell-type dependent. Specifically, cytosolic and mitochondrial NADPH dynamics of MDA-MB-231 decreased in response to serine deprivation, while those of HCT-116 increased in response to serine or glutamine deprivation. Furthermore, by introducing a fractional contribution parameter, we correlated cytosolic and mitochondrial NADPH dynamics to growth rates. Using this parameter, we identified cancer cell lines whose growth rates were selectively inhibited by targeting cytosolic or mitochondrial NADPH metabolism. Mechanistically, we identified citrate transporter as a key mitochondrial transporter that maintains compartmentalized NADPH dynamics and growth rates. Altogether, our results present a significant advance in quantifying the relationship between compartmentalized NADPH dynamics and cancer cell growth rates, highlighting a potential of targeting compartmentalized NADPH metabolism for selective cancer cell growth inhibitions.

Impact of dissociation constant on the detection sensitivity of polymerization-based signal amplification reactions.

Many studies have demonstrated the concept of using free-radical polymerization reactions to provide signal amplification so that molecular recognition events indicative of disease states may be detected in a simple and low-cost manner. We provide the first systematic study of how the dissociation constant impacts detection sensitivity in these assays, having chosen a range of dissociation constants (nanomolar to picomolar) that is typical of those encountered in molecular diagnostic applications that detect protein-protein binding events. In addition, we use experimental results to validate a mass-action kinetic model that may be used to predict assay performance as an alternative or supplement to the empirical approach to developing new polymerization-based amplification assays that has characterized the field to date.