Publications by authors named "Xianghua Luo"

Natural killer (NK) cell tumor infiltration is associated with good prognosis in patients with metastatic castration-resistant prostate cancer (mCRPC). NK cells recognize and kill targets by a process called natural cytotoxicity. We hypothesized that promoting an antigen-specific synapse with co-activation may enhance NK cell function in mCRPC.

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Limited oxygen (hypoxia) in solid tumors poses a challenge to successful immunotherapy with natural killer (NK) cells. NK cells have impaired cytotoxicity when cultured in hypoxia (1% oxygen) but not physiologic (>5%) or atmospheric oxygen (20%). We found that changes to cytotoxicity were regulated at the transcriptional level and accompanied by metabolic dysregulation.

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Randomized trials seek efficient treatment effect estimation within target populations, yet scientific interest often also centers on subpopulations. Although there are typically too few subjects within each subpopulation to efficiently estimate these subpopulation treatment effects, one can gain precision by borrowing strength across subpopulations, as is the case in a basket trial. While dynamic borrowing has been proposed as an efficient approach to estimating subpopulation treatment effects on primary endpoints, additional efficiency could be gained by leveraging the information found in secondary endpoints.

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Background: Reducing cigarette addictiveness has the potential to avert millions of yearly tobacco-related deaths worldwide. Substantially reducing nicotine in cigarettes decreases cigarette consumption, but no large clinical trial has determined the effects of reduced-nicotine cigarettes when other nicotine-containing products are available. The aim of this study was to examine the effects of reduced-nicotine cigarettes in the context of the availability of alternative nicotine delivery systems.

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In small series, third-party fecal microbiota transplantation (FMT) has been successful in decolonizing the gut from clinically relevant antibiotic resistance genes (ARGs). Less is known about the short- and long-term effects of FMT on larger panels of ARGs. We analyzed 226 pre- and post-treatment stool samples from a randomized placebo-controlled trial of FMT in 100 patients undergoing allogeneic hematopoietic cell transplantation or receiving anti-leukemia induction chemotherapy for 47 ARGs.

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The prevalence of combustible cigarette smoking in populations experiencing homelessness in the United States is five times that of the general population. The psychosocial well-being of persons who smoke and experience homelessness is poorer if such persons also use alcohol heavily. The PTQ2 study was a randomized clinical trial among persons experiencing homelessness who were also current smokers and heavy alcohol consumers.

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Purpose: Gut microbiota injury in allogeneic hematopoietic cell transplantation (HCT) recipients and patients with AML has been associated with adverse clinical outcomes. Previous studies in these patients have shown improvements in various microbiome indices after fecal microbiota transplantation (FMT). However, whether microbiome improvements translate into improved clinical outcomes remains unclear.

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Sulfasalazine (SAS) is a repurposed antitumor drug which inhibits the proliferation and survival of cancer cells by inhibiting the xCT cellular antioxidant system. Recent clinical studies have shown that, due to poor bioavailability, the antitumor effects of SAS monotherapy are minimal. Therefore, we hypothesized that DSF, another repurposed drug that has demonstrated anticancer effects, or its complex with copper (DSF-copper, DSF-Cu) could potentiate the antilung cancer effects of SAS.

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Background: Melanoma survivors are at increased risk of developing a second primary melanoma; however, some report sub-optimal sun behaviors and sunburns. We tested the effectiveness of a wearable device with ultraviolet radiation (UVR)-sensing technology to improve sun behaviors and reduce sunburns in cutaneous melanoma survivors.

Materials And Methods: We conducted a randomized controlled trial using Shade 2, a commercially available wrist device that measures UVR.

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Background: Regulation of filter ventilation (FV) has been proposed to reduce misperceptions that ventilation reduces the health risks of smoking. We describe smoking behaviour and exposure after switching to a cigarette brand variant (CBV) with a different FV level.

Methods: Wave 1 (2013-2014) of the Population Assessment of Tobacco Use and Health Study was merged with FV levels of participants' CBV and restricted to adults with a usual CBV, smoked daily and included in wave 4 (2016-2017; n=371).

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Background: Filter ventilation in cigarettes has been associated with alterations in smoking topography in order to compensate for the lower nicotine yields. Subjective effects of cigarettes include sensations, which can be affected by how a person smokes a cigarette. We look at smoking topography as a mediator in the relationship between filter ventilation levels and subjective effects.

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The United States Food and Drug Administration has the authority to reduce the nicotine content in cigarettes to minimal or non-addictive levels and could do so immediately or gradually over time. A large clinical trial compared the two approaches. This secondary analysis assesses abstinence and cessation-related outcomes one month after the trial concluded, when participants no longer had access to very low nicotine content (VLNC) research cigarettes.

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Article Synopsis
  • The study evaluated the uptake of carcinogens and toxicants in e-cigarette users compared to nonsmokers and cigarette smokers by analyzing urine samples over several months.
  • Results showed that e-cigarette users had significantly higher levels of the carcinogen acrolein in their urine than nonsmokers, while other carcinogen levels did not differ significantly between these two groups.
  • Overall, the findings suggest that e-cigarette use may pose a risk for higher exposure to certain harmful substances, raising concerns about their safety.
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Background: In the United States, eighty percent of the adult homeless population smokes cigarettes compared to 15 percent of the general population. In 2017 Power to Quit 2 (PTQ2), a randomized clinical trial, was implemented in two urban homeless shelters in the Upper Midwest to address concurrent smoking cessation and alcohol treatment among people experiencing homelessness. A subset of this study population were interviewed to assess their experiences of study intervention.

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Regression methods, including the proportional rates model and additive rates model, have been proposed to evaluate the effect of covariates on the risk of recurrent events. These two models have different assumptions on the form of the covariate effects. A more flexible model, the additive-multiplicative rates model, is considered to allow the covariates to have both additive and multiplicative effects on the marginal rate of recurrent event process.

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Background: Bivariate alternating recurrent event data can arise in longitudinal studies where patients with chronic diseases go through two states that occur repeatedly, e.g., care periods and break periods.

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Individual participant data meta-analysis is a frequently used method to combine and contrast data from multiple independent studies. Bayesian hierarchical models are increasingly used to appropriately take into account potential heterogeneity between studies. In this paper, we propose a Bayesian hierarchical model for individual participant data generated from the Cigarette Purchase Task (CPT).

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With the aim to improve the communication of trial results, we introduce a novel graphical approach that complements the analysis of time to event outcomes in two-arm randomized trials. We define the so-called two-sample survival probability curve and propose a nonparametric estimator of the curve based on a random walk using Kaplan-Meier survival estimates for the two arms. We then use the estimated curve to visualize treatment effect as well as potential effect modification of factors of interest.

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Background: While evidence demonstrates that the industry's marketing of cigarettes with higher filter ventilation (FV) misleads adults about their health risks, there is no research on the relationships between FV, risk perceptions and smoking trajectories among youth (ages 12-17) and young adults (ages 18-24).

Methods: Data on FV levels of major US cigarette brands/sub-brands were merged with the Population Assessment of Tobacco and Health Study to examine whether FV level in cigarettes used by wave 1 youth/young adults (n=1970) predicted continued smoking at waves 2-4, and whether those relationships were mediated by perceived risk of their cigarette brand. FV was modelled based on tertiles (0.

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Various regression methods have been proposed for analyzing recurrent event data. Among them, the semiparametric additive rates model is particularly appealing because the regression coefficients quantify the absolute difference in the occurrence rate of the recurrent events between different groups. Estimation of the additive rates model requires the values of time-dependent covariates being observed throughout the entire follow-up period.

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A simple approach for analyzing longitudinally measured biomarkers is to calculate summary measures such as the area under the curve (AUC) for each individual and then compare the mean AUC between treatment groups using methods such as t test. This two-step approach is difficult to implement when there are missing data since the AUC cannot be directly calculated for individuals with missing measurements. Simple methods for dealing with missing data include the complete case analysis and imputation.

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Introduction: Studies suggest tobacco and cannabis co-users may experience greater toxicant exposure than exclusive cigarette (ET) smokers. No study has systematically tested differences in toxicant exposure among co-users, exclusive cannabis (ECa) smokers, and ET smokers.

Aims And Methods: Adult daily cigarette smokers and/or weekly cannabis smokers completed two laboratory visits.

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In disease settings where study participants are at risk for death and a serious nonfatal event, composite endpoints defined as the time until the earliest of death or the nonfatal event are often used as the primary endpoint in clinical trials. In practice, if the nonfatal event can only be detected at clinic visits and the death time is known exactly, the resulting composite endpoint exhibits "component-wise censoring." The standard method used to estimate event-free survival in this setting fails to account for component-wise censoring.

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