Biomedical subjects

Lili Tian

Publications and source records attributed to Lili Tian.

At least 19 recordsLinked to original sources

PubMed2026

Machine learning prognostic model and drug survival analysis for lung adenocarcinoma in the context of radiotherapy.

BACKGROUND: Patients with lung adenocarcinoma (LUAD) receiving radiotherapy represent an important but underexplored clinical subgroup. These patients often undergo concomitant pharmacologic treatments, yet the prognostic impact and underlying determinants of such combined regimens remain poorly understood. OBJECTIVE: This retrospective observational study aimed to develop and validate a radiotherapy-specific machine learning prognostic model for LUAD and to compare survival across concomitant pharmacologic regimens. METHODS: In this retrospective observational study, using genomic and clinical data from TCGA, a radiotherapy-specific prognostic model for LUAD was developed and validated through ten machine learning algorithms. Survival analyses were conducted across distinct concomitant pharmacologic strategies, followed by functional enrichment to elucidate molecular mechanisms underlying differential outcomes. RESULTS: Demonstrating robust prognostic abilities, the model efficiently sorted patients into high- and low-risk categories. Both treatment type and risk score independently predicted overall survival, with significant interaction effects. Low-risk patients receiving targeted or combination therapy-mainly erlotinib, gefitinib, or bevacizumab-exhibited substantially improved survival compared with those receiving conventional chemotherapy. Enrichment of "Exogenous peptide presentation," "MHC class II assembly," "Peptide-MHC II assembly," and "Symbiotic interaction" pathways indicated immune modulation and host-tumor crosstalk as key mediators of treatment efficacy. CONCLUSION: This study establishes a radiotherapy-specific prognostic model for lung adenocarcinoma, demonstrating distinct molecular and therapeutic heterogeneity and highlighting the superior survival benefit of targeted combination therapy in low-risk patients.

Humans↗

PubMed2007

Inferences on standardized mean difference: the generalized variable approach.

The standardized mean difference has been widely used as the most common index of effect magnitude in many applied fields. In this paper, we propose a novel approach using the concept of generalized variable for the confidence interval estimation and hypothesis testing of standardized mean difference. Furthermore, we extend this approach to compare standardized mean differences between two studies or between two strata. Simulation results demonstrate that the proposed approach can provide confidence intervals with excellent coverage properties and can perform hypothesis testing with satisfactory type-I error control.

Confidence Intervals↗

PubMed2006

Inferences on the within-subject coefficient of variation.

The within-subject coefficient of variation (WCV) is widely used as a measure of precision and reproducibility of data in medical and biological science. In this paper, generalized confidence intervals and tests for a single WCV is developed using the concept of generalized pivots under the assumption of one-way random effect model. This approach is further extended to two-sample cases. The resulting procedures are easy to compute and have good properties in term of coverage probabilities and type-I error control at small sample sizes. The proposed methods are illustrated by a real life example.

Analysis of Variance↗

PubMed2006

Confidence intervals for the mean of lognormal data with excess zeros.

In this paper, we consider an approach based on the adjusted signed log-likelihood ratio statistic for constructing a confidence interval for the mean of lognormal data with excess zeros. An extensive simulation study suggests that the proposed approach outperforms all the existing methods in terms of coverage probabilities and symmetry of upper and lower tail error probabilities. Finally, we analyzed two real-life datasets using the proposed approach.

Algorithms↗

PubMed2006

Pharmacokinetic evaluation of the drug interaction between intravenous itraconazole and intravenous tacrolimus or intravenous cyclosporin A in allogeneic hematopoietic stem cell transplant recipients.

A single-institution, open-label prospective pharmacokinetic evaluation of the interaction between intravenous itraconazole and intravenous cyclosporin A and tacrolimus was conducted in allogeneic hematopoietic stem cell transplant recipients. The study was conducted in 2 phases, with patients acting as their own controls. In phase 1, steady-state concentrations and clearance of cyclosporin A and tacrolimus administered alone were evaluated. Phase 2 evaluated serum concentrations and clearance of cyclosporin A and tacrolimus under the influence of itraconazole therapy. Among 17 patients who completed both phases of the study, the mean increase in the serum tacrolimus concentration was 83% (P<.0001), and the mean increase in the serum cyclosporin A concentration was 80% (P=.0001). There was no correlation between serum itraconazole concentrations and the serum concentrations of tacrolimus or cyclosporin A. The drug interaction between itraconazole and calcineurin inhibitors is predictable and occurs within 48 hours of concomitant drug administration. The data suggest that dose reductions of tacrolimus and cyclosporin A in the range of 50% to 100% are necessary when itraconazole therapy is initiated and that subsequent close monitoring of serum concentrations is necessary to guide further dose modifications.

Adult↗

PubMed2005

The roles of teaching hospitals, insurance status, and race/ethnicity in receipt of adjuvant therapy for regional-stage breast cancer in Florida.

OBJECTIVES: We examined the roles of teaching hospitals, insurance status, and race/ ethnicity in women's receipt of adjuvant therapy for regional-stage breast cancer. METHODS: Data were taken from the Florida Cancer Data System for cases diagnosed from July 1997 to December 2000. We evaluated the impact of health insurance status and hospital type on use of adjuvant therapy (after adjustment for age, race/ethnicity, and marital status). Interaction terms for hospital type, insurance status, and race/ethnicity were entered in each model. RESULTS: Teaching facilities diagnosed 12.5% of the cases; however, they cared for a disproportionate percentage (21.3%) of uninsured and Medicaid-insured women. Among women who received adjuvant chemotherapy only, those diagnosed in teaching hospitals were more likely than those diagnosed in nonteaching hospitals to receive therapy regardless of insurance status or race/ethnicity. Among women who received chemotherapy with or without hormonal therapy, Hispanics were more likely than White non-Hispanic women to receive therapy, whereas women with private insurance or Medicare were less likely than uninsured and Medicaid-insured women to receive this type of therapy. CONCLUSIONS: Teaching facilities play an important role in the diagnosis and treatment of regional-stage breast cancer among Hispanics, uninsured women, and women insured by Medicaid.

Adult↗

PubMed2005

On confidence intervals of a common intraclass correlation coefficient.

This study presents a novel approach for the confidence interval estimation of a common intraclass correlation coefficient derived from several samples under unequal family sizes. This approach is developed using the concept of generalized pivots. Comparisons are made with a large sample procedure on the coverage probabilities.

Blood Pressure↗

PubMed2005

Inferences on the mean of zero-inflated lognormal data: the generalized variable approach.

This paper considers the problems of confidence interval estimation and hypothesis testing for the mean of zero-inflated lognormal data. We present an unified novel approach based on the concepts of generalized test variables and generalized pivotal quantities. Simulation results demonstrate that the coverage accuracy of proposed confidence intervals and the type I error control of the proposed exact tests are satisfactory.

Air Pollutants, Occupational↗

PubMed2005

Inferences on the common coefficient of variation.

The coefficient of variation is often used as a measure of precision and reproducibility of data in medical and biological science. This paper considers the problem of making inference about the common population coefficient of variation when it is a priori suspected that several independent samples are from populations with a common coefficient of variation. The procedures for confidence interval estimation and hypothesis testing are developed based on the concepts of generalized variables. The coverage properties of the proposed confidence intervals and type-I errors of the proposed tests are evaluated by simulation. The proposed methods are illustrated by a real life example.

Blood↗

PubMed2005

Interval estimation and hypothesis testing of intraclass correlation coefficients: the generalized variable approach.

In this paper, we propose a novel approach using the concept of generalized variable (GV) for the confidence interval estimation of the difference of two intraclass correlation coefficients under unequal family sizes. This approach can also easily provide P-values for hypothesis testing. Simulation results show that the GV approach can provide confidence intervals with good coverage properties and perform hypothesis testing with satisfactory type-I error control. Furthermore, the confidence intervals and P-values by GV approach can be easily obtained by simulation. Therefore the GV approach is a suitable candidate for making inference concerning two intraclass correlation coefficients.

Biometry↗

PubMed2005

Effects of exercise on mental and physical health parameters of persons with schizophrenia.

Although the benefits of exercise are well documented, few published research studies have examined exercise in persons with schizophrenia. This pilot examined a 16-week walking program for outpatients diagnosed with schizophrenia (N = 10). Six-minute walking distance, body mass index, percent body fat and severity of psychiatric symptoms were measured. Experimental participants in the walking group experienced significant reductions in body fat (p = 0.03) compared to a control group not participating in the exercises during the same time period. Experimental participants also had greater aerobic fitness, lower body mass indexes, and fewer psychiatric symptoms than controls at the conclusion of the program. Research is needed to identify effective exercise interventions and feasible delivery modalities for persons with schizophrenia in community settings.

Adult↗

PubMed2005

Arginine supplementation does not enhance serum nitric oxide levels in elderly nursing home residents with pressure ulcers.

The purpose of this study was to determine whether arginine supplementation enhances in vitro (neutrophil burst and mitogen-induced lymphocyte proliferation) and in vivo (delayed-type hypersensitivity [DTH] and serum nitric oxide) measures of immune function in nursing home elders with pressure ulcers. Twenty-six elders, 65 years of age or older, with one or more pressure ulcers, were randomized to receive 8.5 g of arginine or an isonitrogenous supplement for 4 weeks. Immune function studies and serum arginine, ornithine, citrulline, and nitric oxide were measured at baseline, 4 weeks postsupplementation (Week 4) and after a 6-week washout (Week 10). At Week 4, serum ornithine increased (p = .01) and arginine trended to increase (p = .055), but there was no increase in citrulline or nitric oxide with arginine supplementation. There were no differences in neutrophil burst or DTH responses between groups. Whole blood mitogen-induced proliferation decreased significantly at Week 10 in the isonitrogenous but not in the arginine-supplemented group. There is mounting concern that arginine supplementation during an inflammatory state could be detrimental due to overwhelming nitric oxide production. A key finding of this study is that arginine supplementation did not increase serum nitric oxide levels over that observed in elders with pressure ulcers given an isonitrogenous supplement.

Administration, Oral↗

PubMed2005

Managed care organization characteristics and outpatient specialty care use among children with chronic illness.

BACKGROUND: Limited information is available about managed care organization (MCO) characteristics that influence outpatient physician specialist use among children with chronic conditions. OBJECTIVE: To examine the association between MCO characteristics and outpatient physician specialist use among children with chronic conditions who were receiving care in MCOs in which primary care providers (PCPs) served as gatekeepers for referrals and who were publicly insured. DESIGN AND METHODS: A total of 2333 children who had been diagnosed with a chronic condition and had functional limitations, an increased need for or use of health care services beyond what children normally use, and/or dependence on medications or home medical equipment were included in the study. The odds of an outpatient physician specialist visit 1 year after study entry were examined as a function of child health and sociodemographic characteristics, MCO characteristics, the child's prior specialty care use, and provider availability in the MCO service delivery area. RESULTS: Children cared for in MCOs with lower percentages of PCPs paid on a fee-for-service basis (odds ratio: 0.95; 95% confidence interval: 0.92-0.98), with higher percentages of pediatricians in the PCP network (odds ratio: 1.17; 95% confidence interval: 1.07-1.29), and offering financial incentives for meeting quality of care standards (odds ratio: 1.71; 95% confidence interval: 1.28-2.29) had greater odds of outpatient physician specialist visits. Black children had odds of specialty care that were approximately one half those of white children. Children with prior physician specialist use were 52% more likely to have a physician specialist visit in the year after study entry. The children's diagnoses and condition consequences were not related significantly to the odds of a specialty visit. CONCLUSIONS: Specific MCO characteristics were associated with greater specialty care use among a group of low-income children with chronic conditions. Such information should be used to improve the structure of managed care arrangements for these vulnerable children.

Adolescent↗

PubMed2004

An algorithm for molecular dissection of tumor progression.

The volumetric growth of tumor cells as a function of time is most often likely to be a complex trait, controlled by the combined influences of multiple genes and environmental influences. Genetic mapping has proven to be a powerful tool for detecting and identifying specific genes affecting complex traits, i.e., quantitative trait loci (QTL), based on polymorphic markers. In this article, we present a novel statistical model for genetic mapping of QTL governing tumor growth trajectories in humans. In principle, this model is a combination of functional mapping proposed to map function-valued traits and linkage disequilibrium mapping designed to provide high resolution mapping of QTL by making use of recombination events created at a historic time. We implement an EM-simplex hybrid algorithm for parameter estimation, in which a closed-form solution for the EM algorithm is derived to estimate the population genetic parameters of QTL including the allele frequencies and the coefficient of linkage disequilibrium, and the simplex algorithm incorporated to estimate the curve parameters describing the dynamic changes of cancer cells for different QTL genotypes. Extensive simulations are performed to investigate the statistical properties of our model. Through a number of hypothesis tests, our model allows for cutting-edge studies aimed to decipher the genetic mechanisms underlying cancer growth, development and differentiation. The implications of our model in gene therapy for cancer research are discussed.

Algorithms↗

PubMed2004

A new approach for interval estimation and hypothesis testing of a certain intraclass correlation coefficient: the generalized variable method.

We consider the problems of interval estimation and hypothesis testing for the intraclass correlation coefficient in an interrater reliability study when both raters and subjects are assumed to be randomly selected from populations of raters and subjects, respectively. We propose a novel approach for the confidence interval estimation and hypothesis testing using the concepts of generalized confidence interval (GCI) and generalized P-values. A simulation study is conducted to investigate the coverage probabilities of the GCI approach relative to the modified large sample (MLS) approach. Both methods tend to provide somewhat conservative coverage. Relative to the MLS approach, the GCI approach is closer to the correct (nominal) coverage for a two-sided interval, but farther to the correct coverage for a one-sided lower interval. Unlike the MLS approach, the GCI approach can also easily provide P-values. The fact that the GCI approach is suitable for confidence interval estimation and obtaining P-values makes the GCI approach a suitable candidate for making inference about interrater reliability.

Algorithms↗

PubMed2004

Promoting adherence: effects of theory-based asthma education.

This study compared the effects of a theoretically focused audiotape and a standard educational booklet on asthma preventive medication adherence and other asthma outcomes. Forty-six adult asthmatics were randomly assigned to receive either an experimental audiotape incorporating components of protection motivation theory, a standard asthma management booklet, both, or no educational materials. Outcomes were assessed at baseline, 3 months, and 6 months. Mean pharmacy-verified adherence improved 15% to 19% in the intervention groups and declined 22% in the control group at 6 months. Using analysis of covariance (ANCOVA) to control for baseline adherence, these changes were significant between the control and booklet group (t = 2.47; p = .02) and between control and combined group (t = 2.07; p = .04). Providing a minimal educational intervention can have a beneficial effect on asthma medication adherence that persists at least 6 months.

Adolescent↗

PubMed2004

A comparison of the general linear mixed model and repeated measures ANOVA using a dataset with multiple missing data points.

Longitudinal methods are the methods of choice for researchers who view their phenomena of interest as dynamic. Although statistical methods have remained largely fixed in a linear view of biology and behavior, more recent methods, such as the general linear mixed model (mixed model), can be used to analyze dynamic phenomena that are often of interest to nurses. Two strengths of the mixed model are (1) the ability to accommodate missing data points often encountered in longitudinal datasets and (2) the ability to model nonlinear, individual characteristics. The purpose of this article is to demonstrate the advantages of using the mixed model for analyzing nonlinear, longitudinal datasets with multiple missing data points by comparing the mixed model to the widely used repeated measures ANOVA using an experimental set of data. The decision-making steps in analyzing the data using both the mixed model and the repeated measures ANOVA are described.

Analysis of Variance↗

PubMed2002

Endothelin 1 levels in the aqueous humor of dogs with glaucoma.

PURPOSE: Endothelin 1 is a small peptide that is involved in regulation of intraocular pressure and modulation of ocular circulation. To investigate the role of endothelin 1 in canine glaucoma, the authors measured aqueous humor levels of endothelin 1 in healthy dogs and in dogs with hypertensive glaucoma. METHODS: Aqueous humor samples were obtained with general anesthesia from the eyes of healthy dogs (n = 5) and dogs with hypertensive glaucoma (n = 10). Measurements were made by enzyme immunoassay for endothelin 1. RESULTS: The endothelin 1 aqueous humor range was 1.12 - 3.63 pg/mL for healthy dogs and 1.97 - 14.97 pg/mL for glaucomatous dogs. The healthy and glaucomatous canine endothelin 1 aqueous levels (mean +/- SD) were 2.33 +/- 0.90 and 8.11 +/- 5.03 pg/mL, respectively. A two-way analysis of variance indicated that this difference was significant (P = 0.0084). The effect of age on endothelin 1 levels was not significant (P = 0.6283). The large variability found within the glaucomatous group could be explained by the degree of damage of the retina (P = 0.0006). There was no significant correlation between intraocular pressure and endothelin 1 aqueous humor levels within the glaucomatous group (P = 0.29). CONCLUSIONS: The aqueous humor of dogs with hypertensive glaucoma contains significantly higher levels of endothelin 1 than that of healthy dogs.

Animals↗