Machine learning strategies for the structure-property relationship of copolymers.

Establishing the structure-property relationship is extremely valuable for the molecular design of copolymers. However, machine learning (ML) models can incorporate both chemical composition and sequence distribution of monomers, and have the generalization ability to process various copolymer types (e.g., alternating, random, block, and gradient copolymers) with a unified approach are missing. To address this challenge, we formulate four different ML models for investigation, including a feedforward neural network (FFNN) model, a convolutional neural network (CNN) model, a recurrent neural network (RNN) model, and a combined FFNN/RNN (Fusion) model. We use various copolymer types to systematically validate the performance and generalizability of different models. We find that the RNN architecture that processes the monomer sequence information both forward and backward is a more suitable ML model for copolymers with better generalizability. As a supplement to polymer informatics, our proposed approach provides an efficient way for the evaluation of copolymers.

Unified machine learning protocol for copolymer structure-property predictions.

Structure-property relationships are extremely valuable when predicting the properties of polymers. This protocol demonstrates a step-by-step approach, based on multiple machine learning (ML) architectures, which is capable of processing copolymer types such as alternating, random, block, and gradient copolymers. We detail steps for necessary software installation and construction of datasets. We further describe training and optimization steps for four neural network models and subsequent model visualization and comparison using training and test values. For complete details on the use and execution of this protocol, please refer to Tao et al. (2022).1.

The Diagnosis Is in the Smear: A Case and Review of Spur Cell Anemia in Cirrhosis.

The etiology of anemia in liver cirrhosis is multifactorial; one less recognized cause is hemolytic anemia due to spur cells, known as spur cell anemia. We present the case of a 57-year-old woman with alcoholic cirrhosis who presented with symptomatic macrocytic anemia with a hemoglobin level of 7.4 g/dL and signs of decompensated liver disease. Notably, she had no signs of overt bleeding. Further workup was consistent with hemolysis, with peripheral smear demonstrating spur cells. The patient was treated with both steroids and IVIG, although she eventually expired. The characteristic morphology of spur cells is due to alteration of the lipid composition of the erythrocyte membrane, changing its shape and leading to splenic sequestration and destruction. Characteristic of this disorder is an increased ratio of cholesterol to phospholipid on the membrane, as well as low levels of apolipoproteins and low- and high-density lipoproteins. The presence of spur cells is an indicator of poor prognosis and high risk of mortality. Currently, the only definitive cure is liver transplantation. There is a paucity of literature on the prevalence of this phenomenon and even less about treatment. This case highlights the importance of recognition of spur cell anemia as a cause of anemia in cirrhosis as well as the importance of the peripheral smear in the diagnostic workup. Early recognition can lead to avoidance of unnecessary procedures. Further research is needed to elucidate the true prevalence of spur cell anemia and examine further treatment options.

Impact of Cytomegalovirus Viral Load on Probability of Spontaneous Clearance and Response to Preemptive Therapy in Allogeneic Stem Cell Transplantation Recipients.

The optimal viral load threshold at which to initiate preemptive cytomegalovirus (CMV) therapy in hematopoietic cell transplantation (HCT) recipients remains to be defined. In an effort to address this question, we conducted a retrospective study of 174 allogeneic HCT recipients who underwent transplantation at a single center between August 2012 and April 2016. During this period, preemptive therapy was initiated at the discretion of the treating clinician. A total of 109 patients (63%) developed CMV viremia. The median time to reactivation was 17 days (interquartile range, IQR, 7-30 days) post-HCT. A peak viremia ≥150 IU/mL was strongly associated with a reduced probability of spontaneous clearance (relative risk, .16; 95% confidence interval, .1-.27), independent of established clinical risk factors, including CMV donor serostatus, exposure to antithymocyte globulin, and underlying lymphoid malignancy. The median time to clearance of viremia was significantly shorter in those who started therapy at CMV <350 IU/mL (19 days; IQR, 11-35 days) compared with those who started antiviral therapy at higher viremia thresholds (33 days; IQR, 21-42 days; P = .02). The occurrence of treatment-associated cytopenias was frequent but similar in patients who started preemptive therapy at CMV <350 IU/mL and those who started at CMV >350 IU/mL (44% versus 57%; P = .42). Unresolved CMV viremia by treatment day 35 was associated with increased risk of therapeutic failure (32% versus 0%; P = .001). Achieving eradication of CMV viremia by treatment day 35 was associated with a 74% reduction in 1-year nonrelapse mortality (NRM) (adjusted hazard ratio [HR], .26; 95% confidence interval [CI], .1-.8; P = .02), whereas therapeutic failure was associated with a significant increase in the probability of 1-year NRM (adjusted HR, 26; 95% CI, 8-87; P <.0001). We conclude that among allogeneic HCT patients, a peak CMV viremia ≥150 IU/mL is associated with a >80% reduction in the probability of spontaneous clearance independent of ATG administration, CMV donor serostatus, and lymphoid malignancy, and is a reasonable cutoff for preemptive therapy. Delaying initiation of therapy until a CMV value ≥350 IU/mL is associated with more protracted CMV viremia, and unresolved viremia by treatment day 35 is associated with a significant increase in NRM.

Allogeneic Mesenchymal Stem Cells Ameliorate Aging Frailty: A Phase II Randomized, Double-Blind, Placebo-Controlled Clinical Trial.

BACKGROUND: Aging frailty, characterized by decreased physical and immunological functioning, is associated with stem cell depletion. Human allogeneic mesenchymal stem cells (allo-hMSCs) exert immunomodulatory effects and promote tissue repair. METHODS: This is a randomized, double-blinded, dose-finding study of intravenous allo-hMSCs (100 or 200-million [M]) vs placebo delivered to patients (n = 30, mean age 75.5 ± 7.3) with frailty. The primary endpoint was incidence of treatment-emergent serious adverse events (TE-SAEs) at 1-month postinfusion. Secondary endpoints included physical performance, patient-reported outcomes, and immune markers of frailty measured at 6 months postinfusion. RESULTS: No therapy-related TE-SAEs occurred at 1 month. Physical performance improved preferentially in the 100M-group; immunologic improvement occurred in both the 100M- and 200M-groups. The 6-minute walk test, short physical performance exam, and forced expiratory volume in 1 second improved in the 100M-group (p = .01), not in the 200M- or placebo groups. The female sexual quality of life questionnaire improved in the 100M-group (p = .03). Serum TNF-α levels decreased in the 100M-group (p = .03). B cell intracellular TNF-α improved in both the 100M- (p < .0001) and 200M-groups (p = .002) as well as between groups compared to placebo (p = .003 and p = .039, respectively). Early and late activated T-cells were also reduced by MSC therapy. CONCLUSION: Intravenous allo-hMSCs were safe in individuals with aging frailty. Treated groups had remarkable improvements in physical performance measures and inflammatory biomarkers, both of which characterize the frailty syndrome. Given the excellent safety and efficacy profiles demonstrated in this study, larger clinical trials are warranted to establish the efficacy of hMSCs in this multisystem disorder. CLINICAL TRIAL REGISTRATION: www.clinicaltrials.gov: CRATUS (#NCT02065245).

Dose Comparison Study of Allogeneic Mesenchymal Stem Cells in Patients With Ischemic Cardiomyopathy (The TRIDENT Study).

RATIONALE: Cell dose and concentration play crucial roles in phenotypic responses to cell-based therapy for heart failure. OBJECTIVE: To compare the safety and efficacy of 2 doses of allogeneic bone marrow-derived human mesenchymal stem cells identically delivered in patients with ischemic cardiomyopathy. METHODS AND RESULTS: Thirty patients with ischemic cardiomyopathy received in a blinded manner either 20 million (n=15) or 100 million (n=15) allogeneic human mesenchymal stem cells via transendocardial injection (0.5 cc per injection × 10 injections per patient). Patients were followed for 12 months for safety and efficacy end points. There were no treatment-emergent serious adverse events at 30 days or treatment-related serious adverse events at 12 months. The Major Adverse Cardiac Event rate was 20.0% (95% confidence interval [CI], 6.9% to 50.0%) in 20 million and 13.3% (95% CI, 3.5% to 43.6%) in 100 million (P=0.58). Worsening heart failure rehospitalization was 20.0% (95% CI, 6.9% to 50.0%) in 20 million and 7.1% (95% CI, 1.0% to 40.9%) in 100 million (P=0.27). Whereas scar size reduced to a similar degree in both groups: 20 million by -6.4 g (interquartile range, -13.5 to -3.4 g; P=0.001) and 100 million by -6.1 g (interquartile range, -8.1 to -4.6 g; P=0.0002), the ejection fraction improved only with 100 million by 3.7 U (interquartile range, 1.1 to 6.1; P=0.04). New York Heart Association class improved at 12 months in 35.7% (95% CI, 12.7% to 64.9%) in 20 million and 42.9% (95% CI, 17.7% to 71.1%) in 100 million. Importantly, proBNP (pro-brain natriuretic peptide) increased at 12 months in 20 million by 0.32 log pg/mL (95% CI, 0.02 to 0.62; P=0.039), but not in 100 million (-0.07 log pg/mL; 95% CI, -0.36 to 0.23; P=0.65; between group P=0.07). CONCLUSIONS: Although both cell doses reduced scar size, only the 100 million dose increased ejection fraction. This study highlights the crucial role of cell dose in the responses to cell therapy. Determining optimal dose and delivery is essential to advance the field, decipher mechanism(s) of action and enhance planning of pivotal Phase III trials. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02013674.

Allogeneic Human Mesenchymal Stem Cell Infusions for Aging Frailty.

BACKGROUND: Impaired endogenous stem cell repair capacity is hypothesized to be a biologic basis of frailty. Therapies that restore regenerative capacity may therefore be beneficial. This Phase 1 study evaluated the safety and potential efficacy of intravenous, allogeneic, human mesenchymal stem cell (allo-hMSC)-based therapy in patients with aging frailty. METHODS: In this nonrandomized, dose-escalation study, patients received a single intravenous infusion of allo-hMSCs: 20-million (n = 5), 100-million (n = 5), or 200-million cells (n = 5). The primary endpoint was incidence of any treatment-emergent serious adverse events measured at 1 month postinfusion. The secondary endpoints were functional efficacy domains and inflammatory biomarkers, measured at 3 and 6 months, respectively. RESULTS: There were no treatment-emergent serious adverse events at 1-month postinfusion or significant donor-specific immune reactions during the first 6 months. There was one death at 258 days postinfusion in the 200-million group. In all treatment groups, 6-minute walk distance increased at 3 months (p = .02) and 6 months (p = .001) and TNF-α levels decreased at 6 months (p < .0001). Overall, the 100-million dose showed the best improvement in all parameters, with the exception of TNF-α, which showed an improvement in both the 100- and 200-million groups (p = .0001 and p = .0001, respectively). The 100-million cell-dose group also showed significant improvements in the physical component of the SF-36 quality of life assessment at all time points relative to baseline. CONCLUSIONS: Allo-hMSCs are safe and immunologically tolerated in aging frailty patients. Improvements in functional and immunologic status suggest that ongoing clinical development of cell-based therapy is warranted for frailty.

Randomized Comparison of Allogeneic Versus Autologous Mesenchymal Stem Cells for Nonischemic Dilated Cardiomyopathy: POSEIDON-DCM Trial.

BACKGROUND: Although human mesenchymal stem cells (hMSCs) have been tested in ischemic cardiomyopathy, few studies exist in chronic nonischemic dilated cardiomyopathy (NIDCM). OBJECTIVES: The authors conducted a randomized comparison of safety and efficacy of autologous (auto) versus allogeneic (allo) bone marrow-derived hMSCs in NIDCM. METHODS: Thirty-seven patients were randomized to either allo- or auto-hMSCs in a 1:1 ratio. Patients were recruited between December 2011 and July 2015 at the University of Miami Hospital. Patients received hMSCs (100 million) by transendocardial stem cell injection in 10 left ventricular sites. Treated patients were evaluated at baseline, 30 days, and 3-, 6-, and 12-months for safety (serious adverse events [SAE]), and efficacy endpoints: ejection fraction, Minnesota Living with Heart Failure Questionnaire, 6-min walk test, major adverse cardiac events, and immune biomarkers. RESULTS: There were no 30-day treatment-emergent SAEs. Twelve-month SAE incidence was 28.2% with allo-hMSCs versus 63.5% with auto-hMSCs (p = 0.1004 for the comparison). One allo-hMSC patient developed an elevated (>80) donor-specific calculated panel reactive antibody level. The ejection fraction increased in allo-hMSC patients by 8.0 percentage points (p = 0.004) compared with 5.4 with auto-hMSCs (p = 0.116; allo vs. auto p = 0.4887). The 6-min walk test increased with allo-hMSCs by 37.0 m (p = 0.04), but not auto-hMSCs at 7.3 m (p = 0.71; auto vs. allo p = 0.0168). MLHFQ score decreased in allo-hMSC (p = 0.0022) and auto-hMSC patients (p = 0.463; auto vs. allo p = 0.172). The major adverse cardiac event rate was lower, too, in the allo group (p = 0.0186 vs. auto). Tumor necrosis factor-α decreased (p = 0.0001 for each), to a greater extent with allo-hMSCs versus auto-hMSCs at 6 months (p = 0.05). CONCLUSIONS: These findings demonstrated safety and clinically meaningful efficacy of allo-hMSC versus auto-hMSC in NIDCM patients. Pivotal trials of allo-hMSCs are warranted based on these results. (Percutaneous Stem Cell Injection Delivery Effects on Neomyogenesis in Dilated Cardiomyopathy [PoseidonDCM]; NCT01392625).

Spatial and temporal patterns in preterm birth in the United States.

BACKGROUND: Despite years of research, the etiologies of preterm birth remain unclear. In order to help generate new research hypotheses, this study explored spatial and temporal patterns of preterm birth in a large, total-population dataset. METHODS: Data on 145 million US births in 3,000 counties from the Natality Files of the National Center for Health Statistics for 1971-2011 were examined. State trends in early (<34 wk) and late (34-36 wk) preterm birth rates were compared. K-means cluster analyses were conducted to identify gestational age distribution patterns for all US counties over time. RESULTS: A weak association was observed between state trends in <34 wk birth rates and the initial absolute <34 wk birth rate. Significant associations were observed between trends in <34 wk and 34-36 wk birth rates and between white and African American <34 wk births. Periodicity was observed in county-level trends in <34 wk birth rates. Cluster analyses identified periods of significant heterogeneity and homogeneity in gestational age distributional trends for US counties. CONCLUSION: The observed geographic and temporal patterns suggest periodicity and complex, shared influences among preterm birth rates in the United States. These patterns could provide insight into promising hypotheses for further research.

AKI in hospitalized children: comparing the pRIFLE, AKIN, and KDIGO definitions.

BACKGROUND AND OBJECTIVES: Although several standardized definitions for AKI have been developed, no consensus exists regarding which to use in children. This study applied the Pediatric RIFLE (pRIFLE), AKI Network (AKIN), and Kidney Disease Improving Global Outcomes (KDIGO) criteria to an anonymized cohort of hospitalizations extracted from the electronic medical record to compare AKI incidence and outcomes in intensive care unit (ICU) and non-ICU pediatric populations. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Observational, electronic medical record-enabled study of 14,795 hospitalizations at the Lucile Packard Children's Hospital between 2006 and 2010. AKI and AKI severity stage were defined by the pRIFLE, AKIN, and KDIGO definitions according to creatinine change criteria; urine output criteria were not used. The incidences of AKI and each AKI stage were calculated for each classification system. All-cause, in-hospital mortality and total hospital length of stay (LOS) were compared at each subsequent AKI stage by Fisher exact and Kolmogorov-Smirnov tests, respectively. RESULTS: AKI incidences across the cohort according to pRIFLE, AKIN, and KDIGO were 51.1%, 37.3%, and 40.3%. Mortality was higher among patients with AKI across all definitions (pRIFLE, 2.3%; AKIN, 2.7%; KDIGO, 2.5%; P<0.001 versus no AKI [0.8%-1.0%]). Within the ICU, pRIFLE, AKIN, and KDIGO demonstrated progressively higher mortality at each AKI severity stage; AKI was not associated with mortality outside the ICU by any definition. Both in and outside the ICU, AKI was associated with significantly higher LOS at each AKI severity stage across all three definitions (P<0.001). Definitions resulted in differences in diagnosis and staging of AKI; staging agreement ranged from 76.7% to 92.5%. CONCLUSIONS: Application of the three definitions led to differences in AKI incidence and staging. AKI was associated with greater mortality and LOS in the ICU and greater LOS outside the ICU. All three definitions demonstrated excellent interstage discrimination. While each definition offers advantages, these results underscore the need to adopt a single, universal AKI definition.