Mixtures of t $$ t $$ factor analysers with censored responses and external covariates: An application to educational data from Peru

Analysing data from educational tests allows governments to make decisions for improving the quality of life of individuals in a society. One of the key responsibilities of statisticians is to develop models that provide decision-makers with pertinent information about the latent process that educational tests seek to represent. Mixtures oft $$ t $$ factor analysers (MtFA) have emerged as a powerful device for model-based clustering and classification of high-dimensional data containing one or several groups of observations with fatter tails or anomalous outliers. This paper considers an extension of MtFA for robust clustering of censored data, referred to as the MtFAC model, by incorporating external covariates. The enhanced flexibility of including covariates in MtFAC enables cluster-specific multivariate regression analysis of dependent variables with censored responses arising from upper and/or lower detection limits of experimental equipment. An alternating expectation conditional maximization (AECM) algorithm is developed for maximum likelihood estimation of the proposed model. Two simulation experiments are conducted to examine the effectiveness of the techniques presented. Furthermore, the proposed methodology is applied to Peruvian data from the 2007 Early Grade Reading Assessment, and the results obtained from the analysis provide new insights regarding the reading skills of Peruvian students.

Identification of hub genes associated with spermatogenesis by bioinformatics analysis

Spermatogenesis is a complex process related to male infertility. Till now, the critical genes and specific mechanisms have not been elucidated clearly. Our objective was to determine the hub genes that play a crucial role in spermatogenesis by analyzing the differentially expressed genes (DEGs) present in non-obstructive azoospermia (NOA) compared to OA and normal samples using bioinformatics analysis. Four datasets, namely GSE45885, GSE45887, GSE9210 and GSE145467 were used. Functional enrichment analyses were performed on the DEGs. Hub genes were identified based on protein-protein interactions between DEGs. The expression of the hub genes was further examined in the testicular germ cell tumors from the TCGA by the GEPIA and validated by qRT-PCR in the testes of lipopolysaccharide-induced acute orchitis mice with impaired spermatogenesis. A total of 203 DEGs including 34 up-regulated and 169 down-regulated were identified. Functional enrichment analysis showed DEGs were mainly involved in microtubule motility, the process of cell growth and protein transport. PRM2, TEKT2, FSCN3, UBQLN3, SPATS1 and GTSF1L were identified and validated as hub genes for spermatogenesis. Three of them (PRM2, FSCN3 and TEKT2) were significantly down-regulated in the testicular germ cell tumors and their methylation levels were associated with the pathogenesis. In summary, the hub genes identified may be related to spermatogenesis and may act as potential therapeutic targets for NOA and testicular germ cell tumors.

Regorafenib induces damage-associated molecular patterns, cancer cell death and immune modulatory effects in a murine triple negative breast cancer model

Damage associated molecular patterns (DAMPs), including calreticulin (CRT) exposure, high-mobility group box 1 protein (HMGB1) elevation, and ATP release, characterize immunogenic cell death (ICD) and may play a role in cancer immunotherapy. Triple negative breast cancer (TNBC) is an immunogenic subtype of breast cancer with higher lymphocyte infiltration. Here, we found that regorafenib, a multi-target angiokinase inhibitor previously known to suppress STAT3 signaling, induced DAMPs and cell death in TNBC cells. Regorafenib induced the expression of HMGB1 and CRT, and the release of ATP. Regorafenib-induced HMGB1 and CRT were attenuated following STAT3 overexpression. In a 4T1 syngeneic murine model, regorafenib treatment increased HMGB1 and CRT expression in xenografts, and effectively suppressed 4T1 tumor growth. Immunohistochemical staining revealed increased CD4⁺ and CD8⁺ tumor-infiltrating T cells in 4T1 xenografts following regorafenib treatment. Regorafenib treatment or programmed death-1 (PD-1) blockade using anti-PD-1 monoclonal antibody reduced lung metastasis of 4T1 cells in immunocompetent mice. While regorafenib increases the proportion of MHC II high expression on dendritic cells in mice with smaller tumors, the combination of regorafenib and PD-1 blockade did not show a synergistic effect on anti-tumor activity. These results suggest that regorafenib induces ICD and suppresses tumor progression in TNBC. It should be carefully evaluated when developing a combination therapy with an anti-PD-1 antibody and a STAT3 inhibitor.

[Efficacy and safety of intravitreal dexamethasone implant in diabetic macular edema patients with and without prior vitrectomy: a retrospective cohort study]

Objective: To evaluate the effectiveness and safety of intravitreal dexamethasone implant (IDI) in diabetic macular edema (DME) patients with and without prior vitrectomy. Methods: A retrospective cohort study was conducted on DME patients who received IDI treatment at the Aier Eye Hospital, Beijing from March 2018 to August 2020. Patients were divided into two groups according to whether they had undergone vitrectomy or not. Clinical and follow-up data, including best-corrected visual acuity (BCVA), intraocular pressure (IOP), central macular thickness (CMT), occurrence of ocular and systemic complications, and time to DME recurrence and retreatment, were collected before and after IDI injection at 15 days, 1, 2, 3, and 6 months. Statistical analyses were performed using t-test, Mann-Whitney U-test, χ² test or Fisher's exact test, and generalized estimating equations. Results: Thirty-six patients (41 eyes) were included, with 19 patients (21 eyes) in the vitrectomy group and 17 patients (20 eyes) in the non-vitrectomy group. Compared with baseline, BCVA of eyes in the vitrectomy group was significantly improved at 15 days after IDI injection, with values of 1.00 (0.52, 1.31) and 0.61 (0.30, 1.00), respectively (Z=-2.10, P=0.036); BCVA of eyes in the non-vitrectomy group was significantly improved at 1 month after IDI injection, with values of 0.76 (0.60, 1.35) and 0.52 (0.10, 0.70), respectively (Z=-2.24, P=0.025). Compared with baseline, CMT of eyes in both groups was significantly reduced at all follow-up time points after 15 days of IDI injection (all P<0.05). In the vitrectomy group, CMT before and 15 days after injection were 487 (438, 661) μm and 389 (340, 553) μm, respectively (Z=-3.45, P<0.001); in the non-vitrectomy group, CMT before and 15 days after injection were 486 (410, 641) μm and 323 (290, 396) μm, respectively (Z=-4.07, P<0.001). There were no statistically significant differences in BCVA and CMT between the two groups at all follow-up time points (all P>0.05). The time to DME recurrence was 3.0 (3.0, 4.0) months in the vitrectomy group and 5.0 (4.0, 5.0) months in the non-vitrectomy group, with no significant difference between the two groups (P=0.675). Four eyes (19.0%) in the vitrectomy group and three eyes (15.0%) in the non-vitrectomy group had high IOP, with no significant difference (P=0.529). No severe ocular or systemic complications were observed in any patients. Conclusions: IDI treatment is safe and effective in DME patients with and without prior vitrectomy, with similar efficacy, but with faster onset of action in patients with prior vitrectomy. There was no significant difference in DME recurrence within 6 months after IDI injection between the two groups.

[Observation of the efficacy of autologous mucosal transplantation to prevent esophageal stricture after near-circumferential endoscopic submucosal dissection for early esophageal cancer]

Objective: To investigate the efficacy of autologous mucosal transplantation to prevent esophageal stricture after near-circumferential endoscopic submucosal dissection (ESD) for early esophageal cancer. Methods: The case data of 33 patients, who underwent near-circumferential ESD for early esophageal cancer and were followed up regularly in the First Affiliated Hospital of Zhengzhou University from April 2017 to July 2022, were analyzed retrospectively, including 14 males and 19 females, aged (66.4±7.4) (47-77) years. According to the different treatment methods, they were divided into 4 groups: group A (6 cases) were treated with autologous mucosa transplantation and fully covered metal stent implantation, combined with oral, intravenous and local injection of hormone; Group B (8 cases) were treated with autologous mucosa transplantation and fully covered metal stent implantation; Group C (11 cases) were treated with fully covered metal stent implantation combined with oral or intravenous hormone; Group D (8 cases) were treated with fully covered metal stent implantation. After the operation, the growth of the transplanted mucosa, esophageal stricture and surgical complications were observed by endoscopy, so as to understand the efficacy of automucosa transplantation in preventing esophageal stricture after near-circumferential ESD for early esophageal cancer. Results: The gastroscopic operation was successful in 33 patients. The times of expansion in groups B, C and D were more than that in group A, and the times of expansion [M(Q₁,Q₃)] in group A were 0(0, 1.8) times, while the times of expansion in group B, C and D were 5.5(4.3, 6.8), 4.0(4.0, 7.0) and 5.5(3.5, 10.8) times, respectively, with statistical significance (all P<0.05). There was no significant difference in times of expansion among groups B, C and D (all P>0.05). The stent placement time [M(Q₁,Q₃)] in group B [7.5(6.3, 8.8) days] was shorter than that in group A [64.5(41.5, 75.5) days] (P=0.006). There was no significant difference in stent placement time between group C [38.0(28.0, 50.0) days] and group D [31.5(27.3, 66.3) days] and group A (both P>0.05). The stent placement time in group C was longer than that in group B (P<0.05).There was no significant difference in stent placement time between group B, C and D (all P>0.05). There was no significant difference in the incidence of complications among the groups (all P>0.05). Conclusions: Autologous mucosal transplantation is safe and effective in preventing stenosis after near-circumferential ESD for early esophageal cancer. The effect of autologous mucosal transplantation combined with fully covered metal stent placement, systemic and local steroid application in preventing esophageal stricture after near-circumferential ESD for early esophageal cancer is better than that of single application.

Flexible modeling of multiple nonlinear longitudinal trajectories with censored and non-ignorable missing outcomes

Multivariate nonlinear mixed-effects models (MNLMMs) have become a promising tool for analyzing multi-outcome longitudinal data following nonlinear trajectory patterns. However, such a classical analysis can be challenging due to censorship induced by detection limits of the quantification assay or non-response occurring when participants missed scheduled visits intermittently or discontinued participation. This article proposes an extension of the MNLMM approach, called the MNLMM-CM, by taking the censored and non-ignorable missing responses into account simultaneously. The non-ignorable missingness is described by the selection-modeling factorization to tackle the missing not at random mechanism. A Monte Carlo expectation conditional maximization algorithm coupled with the first-order Taylor approximation is developed for parameter estimation. The techniques for the calculation of standard errors of fixed effects, estimation of unobservable random effects, imputation of censored and missing responses and prediction of future values are also provided. The proposed methodology is motivated and illustrated by the analysis of a clinical HIV/AIDS dataset with censored RNA viral loads and the presence of missing CD4 and CD8 cell counts. The superiority of our method on the provision of more adequate estimation is validated by a simulation study.

[Progress in perioperative management of ABO-incompatible pediatric liver transplantation]

ABO incompatible(ABO-I) liver grafts will affect the prognosis of liver transplantation. With the improvement of perioperative treatment,including plasma exchange,rituximab,splenectomy,etc.,the prognosis of ABO-I liver transplantation has been greatly improved. Because children's immune systems are not fully developed,the perioperative management of ABO-I pediatric liver transplantation is significantly different from that of adults. Reducing the perioperative anti-donor ABO antibody titer is the key to the perioperative management of ABO-I liver transplantation. This article summarizes literatures on the perioperative management of ABO-I pediatric liver transplantation, including the perioperative anti-rejection regimen in pediatric recipients of different ages, splenectomy, postoperative monitoring and postoperative complications, etc.

[Comparison of clinical features of JAK2V617F gene mutation and non-mutation in patients with Budd-Chiari syndrome]

Objective: To investigate the clinical features of JAK2V617F gene mutation and non-mutation in patients with Budd-Chiari syndrome (BCS). Methods: 17 and 127 BCS cases with JAK2V617F gene mutation (mutation group) and non-gene mutation (non-mutation group) who were continuously treated with interventional therapy between January 2016 to December 2020 in the Affiliated Hospital of Xuzhou Medical University were selected as the research object for a comparative study. The hospitalization and follow-up data of the two groups were analyzed retrospectively, and the deadline for follow-up was June 2021. Quantitative data group differences were analyzed using the independent sample t-test and Wilcoxon rank sum test. Qualitative data group differences were analyzed with χ² test or Fisher's exact test. Mann-Whitney U test was used to analyze the differences between groups in rank data. Kaplan-Meier method was used to calculate the patient survival and recurrence rate. Results: Age [(35.41±17.10) years vs. (50.09±14.16) years, t=3.915, P<0.001], time of onset (median duration: 3 months vs. 12 months), and the cumulative survival rate (65.5% vs 95.1%; χ²=5.21, P=0.022) were lower in mutation than non-mutation group. Aaspartate aminotransferase, alanine aminotransferase, prothrombin time, Child-Pugh score, Rotterdam score, Model for End-stage Liver Disease score, hepatic vein thrombosis incidence, and the cumulative recurrence rate after intervention were higher in mutation than non-mutation group. The above all indexes had statistically significant differences (P<0.05) between the groups. Conclusion: Younger age, acute onset, severe liver injury, high incidence of hepatic vein thrombosis, and poor prognosis are the features of patients with BCS with JAK2V617F gene mutation than non-mutation.

[Research Progress on Reproductive System Damage in Male Coronavirus Disease 2019 Patients]

The incidence and severity of coronavirus disease 2019(COVID-19) have significant gender differences.Males are more likely to contract severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) than the age-matched females.The virus uses angiotensin-converting enzyme 2(ACE2) receptors to enter human cells.In addition to infecting the respiratory system,ACE2 can also attack the digestive system,nervous system,immune system and so on,due to the various levels of expression in multiple human organs.The testes are one of the ACE2-rich organs.SARS-CoV-2 has been detected in the semen of some COVID-19 patients,which suggests that SARS-CoV-2 may damage the male reproductive system.However,the damage mechanism remains to be studied.The available studies focus on the short-term effect of SARS-CoV-2 on male reproduction and increasing attention has been paid to the long-term effect.This paper briefly describes the possible mechanisms of reproductive cell damage,hypogonadism,and testicular inflammation mediated by SARS-CoV-2 in male COVID-19 patients and points out the existing problems in the current studies,which will broaden the thinking for deciphering the mechanism of reproductive system damage in male COVID-19 patients.

Interfering B cell receptor signaling via SHP-1/p-Lyn axis shows therapeutic potential in diffuse large B-cell lymphoma

Background

Diffuse large B cell lymphoma (DLBCL) is an aggressive and molecularly heterogeneous non-Hodgkin’s lymphoma. The B cell receptor (BCR) signaling pathway in DLBCL emerges as a new drug target. Protein phosphatase SHP-1 negatively regulates several oncogenic tyrosine kinases and plays a tumor suppressive role.

Methods

The direct SHP-1 agonists were used to evaluate the potential therapeutic implication of SHP-1 in DLBCL. Immunohistochemical staining for SHP-1 was quantified by H-score. The SHP-1 phosphatase activity was determined using tyrosine phosphatase assay. In vitro studies, including MTT, western blot analysis and cell apoptosis, were utilized to examined biological functions of SHP-1.

Results

Oral administration of SHP-1 agonist showed the potent anti-tumor effects compared to a selective Bruton’s tyrosine kinase (BTK) inhibitor ibrutinib in mice bearing U2932 xenografts. SHP-1 agonist increased SHP-1 activity as well as downregulated p-Lyn in vivo. Here, we demonstrated that immunohistochemical staining for SHP-1 expression was positive in 76% of DLBCL samples. SHP-1 agonist exerted anti-proliferative and apoptotic effects compared with ibrutinib in DLBCL cells. Mechanistically, SHP-1 agonist decreased BCR signaling, especially p-Lyn, and led to apoptosis.

Conclusions

These data suggest that SHP-1 negatively regulates phosphorylation of Lyn, and targeting SHP-1/p-Lyn using SHP-1 agonist has therapeutic potential for treatment of DLBCL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00518-0.

Multivariate linear mixed models with censored and nonignorable missing outcomes, with application to AIDS studies

The analysis of multivariate longitudinal data could encounter some complications due to censorship induced by detection limits of the assay and nonresponse occurring when participants missed scheduled visits intermittently or discontinued participation. This paper establishes a generalization of the multivariate linear mixed model that can accommodate censored responses and nonignorable missing outcomes simultaneously. To account for the nonignorable missingness, the selection approach which decomposes the joint distribution as a marginal distribution for the primary outcome variables and a model describing the missing process conditional on the hypothetical complete data is used. A computationally feasible Monte Carlo expectation conditional maximization algorithm is developed for parameter estimation with the maximum likelihood (ML) method. Furthermore, a general information-based approach is presented to assess the variability of ML estimators. The techniques for the prediction of censored responses and imputation of missing outcomes are also discussed. The methodology is motivated and exemplified by a real dataset concerning HIV-AIDS clinical trials. A simulation study is conducted to examine the performance of the proposed method compared with other traditional approaches.

Abstract 5127: Significance of Trop-2 in HER2-positive breast cancer

Purpose: The glycoprotein Trop-2 is frequently overexpressed in human malignancies and linked to worse outcome. A Trop2-targeting antibody-drug conjugate, sacituzumab govitecan, has been approved by the FDA for patients with unresectable locally advanced or metastatic triple-negative breast cancer. Trop-2 enhances Akt phosphorylation in numerous cancer cell lines, while the opposite findings are also reported suggesting the cell context-dependent effect of Trop-2. Blockade of PI3K/Akt pathway mediates anti-tumor mechanism of anti-HER2 agents. In this study, we aim to investigate the role of Trop-2 in HER2-positive breast cancer.

Experimental design: The archival samples comprising different breast cancer subtypes were analyzed using immunohistochemical staining. The public databases, including, Metabric, KM plotter, ROC plotter, were used to verify the prognostic role and clinical significance of Trop-2 in HER2-positive breast cancer. In vitro tumor models, the transwell migration, invasion and sphere assays, were applied for evaluation of cancer progression. The apoptotic cells were determined by flow cytometry using Annexin V/propidium iodide double staining.

Results: We analyzed a cohort of 986 breast cancer patients and found that HER2-positive breast cancer harbored higher Trop-2 protein expression than other breast cancer subtypes. Higher levels of Trop-2 and phospho-Akt in HER2-positive breast cancer tissues compared with normal tissues. Trop-2 expression was correlated with tumor stage and phospho-Akt level. HER2-positive breast cancer patients with high level of Trop-2 protein were linked to worse recurrence-free survival. Consistently, data from the public databases exhibited patients with higher level of Trop-2 transcript had shorter recurrence-free survival and overall survival of HER2-positive breast cancer. Overexpression of Trop-2 increased cell migration, invasion and sphere number in SK-BR-3 and BT-474 cells. In contrast, knockdown of Trop-2 suppressed cell motility and sphere formation. Trop-2-expressing cells had better cell viability compared to control cells in the presence of lapatinib or neratinib treatment. Lapatinib- and neratinib-induced cell apoptosis was rescued by Trop-2 overexpression. Notably, patients responded to anti-HER2 therapy had lower Trop-2 transcript expression than non-responders.

Conclusion: These results suggested that the oncogenic role of Trop-2 in HER2-positive breast cancer and Trop-2 expression might confer resistance to anti-HER2 therapy.

Citation Format: Chun-Yu Liu, Ji-Lin Chen, Pei-Yi Chu, Chun-Teng Huang, Wan-Lun Wang, Chi-Cheng Huang, Po-Han Lin, Ling-Ming Tseng. Significance of Trop-2 in HER2-positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5127.

[Review of risk evaluation scores for benign end stage liver diseases recipients]

Liver transplant is an unreplaceable method for benign end-stage liver disease. The risk evaluation for the waiting list recipients and for post-transplant survival could provide practical indication for organ allocation. In recent years, there are two major kinds of evaluation scores. The first kind of evaluation scores is based on model for end-stage liver disease(MELD) score,including SOFT/P-SOFT score,UCLA-FRS score and BAR score. The other evaluation system is based on the concept of acute-on-chronic liver failure,including CLIF-C-ACLF score,TAM score,AARC-ACLF score and COSSH-ACLF score. The scores based on ACLF have been shown superior power in predicting waiting list survival and post-transplant prognosis than MELD. This article reviews the two kinds of evaluation scores,aiming for the better allocation policy and the better prognosis of benign end-stage liver disease.

[Review of risk evaluation scores for benign end stage liver diseases recipients]

Liver transplant is an unreplaceable method for benign end-stage liver disease. The risk evaluation for the waiting list recipients and for post-transplant survival could provide practical indication for organ allocation. In recent years, there are two major kinds of evaluation scores. The first kind of evaluation scores is based on model for end-stage liver disease(MELD) score,including SOFT/P-SOFT score,UCLA-FRS score and BAR score. The other evaluation system is based on the concept of acute-on-chronic liver failure,including CLIF-C-ACLF score,TAM score,AARC-ACLF score and COSSH-ACLF score. The scores based on ACLF have been shown superior power in predicting waiting list survival and post-transplant prognosis than MELD. This article reviews the two kinds of evaluation scores,aiming for the better allocation policy and the better prognosis of benign end-stage liver disease.

[Safety and efficacy of percutaneous mechanical thrombectomy through ipsilateral calf venous access in the treatment of entire-limb acute deep venous thrombosis]

Objective: To evaluate the safety and clinical efficacy of percutaneous mechanical thrombectomy (PMT) through ipsilateral calf venous access in the treatment of entire-limb acute deep vein thrombosis (DVT). Methods: From July 2017 to August 2020, the clinical data of patients with entire-limb acute DVT at Renji Hospital, School of Medicine, Shanghai Jiaotong University treated by AngioJet through ipsilateral calf venous access were analyzed retrospectively. All patients received rivaroxaban or warfarin anticoagulant therapy for at least 6 months after operation. Pressure gradient socks were given routinely after operation. All patients were followed up at 3, 6, 12 months and every year after operation. The primary end points were the 12-month primary patency rate and the incidence of post thrombotic syndrome (PTS). The secondary end points included the thrombus clearance rate, total complication rate, bleeding complication rate and the 12-month incidence of moderate to severe PTS. Results: A total of 31 patients were included in the study. The age ranged from 31 to 80 (63±14) years, including 16 males and 15 females, 23 left lower limb DVT and 8 right lower limb DVT. There were 15 cases treated through peroneal venous access, 6 cases through anterior tibial venous access and 10 cases through posterior tibial venous access. Moreover, 9 cases underwent combined catheter-directed thrombolysis, 25 cases underwent iliac vein percutaneous transluminal angioplasty (PTA), and 10 cases underwent iliac vein stenting. The thrombus clearance rate was grade Ⅱ in 19 cases (61.3%) and grade Ⅲ in 12 cases (38.7%). One patient (3.2%) with anterior tibial venous access developed hematoma at the puncture site, which was improved after pressure bandage, and there were no other bleeding and serious complications. All the 31 patients were followed up for at least 12 months, with an average follow-up period of (22±9) months. The 12-month primary patency rate was 77.4% (24/31). The 12-month incidence of PTS was 16.1% (5/31) and the incidence of moderate to severe PTS was 3.2% (1/31). Conclusions: PMT through ipsilateral calf venous access is safe and effective in the treatment of entire-limb acute DVT. Thrombus in the distal popliteal vein can be one-stage removed and the incidence of PTS is low. It is considered as the first choice of access for the endovascular treatment of entire-limb acute DVT.

[Analysis of curative efficacy of transjugular intrahepatic portosystemic shunt using viabahn stent in the treatment of Budd-Chiari syndrome with extensive hepatic vein occlusion]

Objective: To investigate the efficacy of transjugular intrahepatic portosystemic shunt (TIPS) using viabahn stent in patients with Budd-Chiari syndrome (BCS) with extensive hepatic vein occlusion. Methods: Technical success rates, portal pressure gradient (PPG), complications and shunt patency rate of 25 cases with BCS with extensive hepatic vein occlusion treated by TIPS using viabahn stent were retrospectively analyzed. Color Doppler ultrasound was used for postoperative follow-up. Patency rates were evaluated by Kaplan-Meier curve. Results: The technical success rate of TIPS was 100%. Mean PPG decreased from (22.7 ± 6.2) mmHg preoperatively to (9.7 ± 2.6) mmHg postoperatively (t = 9.58, P < 0.05). Hepatic encephalopathy incidence was 8.0% (2/25), and there were no complications such as intra-abdominal hemorrhage. Twenty-five cases were followed up for 1 to 39 ( mean 19.0 ± 11.9) months, and one patient died of liver failure three months after interventional treatment. The primary patency rates at 1, 2, and 3 years after interventional treatment were 91.3%, 91.3%, and 78.2%, respectively, while the repatency rates were 100%, 92.9%, and 92.9%, respectively. Conclusion: TIPS using viabahn stent can bring better short-term and mid-term curative efficacy in treatment of BCS with extensive hepatic vein occlusion.

[A prospective before-after self-control study of the scenario simulation teaching of junior nurses in a burns department on the fluid resuscitation care of massive burn patients during shock stage]

Objective: To explore the effects of scenario simulation teaching of junior nurses in a burns department on the fluid resuscitation care of massive burn patients during shock stage. Methods: From March 2018 to July 2019, 25 junior nurses fixed in the Department of Burn of Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine met the inclusion criteria and were recruited in this prospective before-after self-control study, including 21 females and 4 males, aged 23 to 26 years. They had a work experience of 1.0 (1.0, 2.0) years in the Department of Burn. Three teaching scenarios were made according to the three major problems in the fluid resuscitation nursing of extensive burn patients during shock stage. The teaching plans were written based on the theoretical framework of Jeffrie's nursing simulation teaching. The high feasibility and practicability of the teaching plans was verified through expert consultation and evaluation by junior nurses. According to the three scenarios in the teaching plan, the junior nurses were performed with scenario simulation teaching, with 2 hours for each scenario, 6 hours in total. In one month before and after the teaching (hereinafter referred to as before and after teaching), the comprehensive ability of junior nurses was evaluated by the teachers using the self-designed junior nurse comprehensive ability evaluation scale, and their behaviors were evaluated by themselves with Performance Self-rating Scale for Nursing Students on High Simulation Training. Data were statistically analyzed with paired sample t test. Results: After teaching, the scores on communication skills, patient admissions, condition assessments, fluid resuscitation, emergency treatment, drug management, nursing skills, instrument use, teamwork, and humanitarian care and total score in the comprehensive ability evaluation of junior nurses as evaluated by teachers were significantly higher than those before teaching (t=-8.060, -11.421, -17.232, -24.800, -4.670, -11.916, -12.131, -11.606, -14.632, -13.325, -25.068, P<0.01), with 4 items including fluid resuscitation, condition assessment, nursing skills, and equipment operation having higher scores. After teaching, the nurses' self-rating scores on communication, division of labor and cooperation, clinical decision-making, professional knowledge and skills, and professional development and critical thinking and total score were (4.6±0.4), (4.8±0.3), (4.6±0.3), (4.6±0.4), (4.6±0.4), and (23.2±1.5) points respectively, which were significantly higher than the corresponding scores of (4.1±0.7), (4.2±0.7), (3.9±0.5), (3.7±0.6), (3.9±0.5), and (18.8±2.6) points before teaching (t=-3.361, -5.721, -6.987, -7.923, -7.922, -7.367, P<0.01). Conclusions: With solving the practical problems in nursing works of fluid resuscitation care of massive burn patients during shock stage as entry point, scenario simulation teaching aims to train the clinical practice ability and adaptability of junior nurses, thereby improving junior nurses' comprehensive ability of clinical practice in the fluid resuscitation care of massive burn patients during shock stage, enhancing their self-confidence and critical thinking ability.

[A cross-sectional study on psychological needs of family members of critically ill inpatients in semi-closed wards and analysis of influence factors]

Objective: To analyze and discuss the psychological needs of family members of critically ill burn inpatients in semi-closed wards and their related influence factors. Methods: A cross-sectional survey was conducted among the 82 burn patients, who met the inclusion criteria and were admitted to the Department of Burns and Plastic Surgery of Ruijin Hospital of Shanghai Jiao Tong University School of Medicine from October 2018 to April 2019, and their family members. A general condition questionnaire of 15 indexes was applied to investigate the general data of burn patients and their family members including cause of burn, gender, age, total burn area, burn depth, burn severity, burn site, and type of medical insurance of patients, kinship with the patients, gender, age, experience of accompanying in intensive care isolation wards, occupation, education level, and monthly income of their family members. The Critical Care Family Needs Inventory (CCFNI) was used to assess each item, each factor, and total scores of the family members of patients including 5 factors and 45 items such as support scale (SS), comfort scale (CS), information scale (IS), proximity scale (PS), assurance scale (AS). CCFNI was used to assess the total scores of patients and their family members after classification according to the general data, the data were statistically analyzed with one-way analysis of variance or independent sample t test. Indicators with statistical significance in the above analysis were selected for multiple linear regression analysis to screen the independent influence factors of psychological needs of patients' family members. CCFNI was used to assess each dimension scores of patients and their family members after classification according to the aforementioned selected independent influence factors including age and burn area of patients, gender, educational level, and experience of accompanying in intensive care isolation wards of their family members, and the data were statistically analyzed with one-way analysis of variance or independent sample t test. Results: A total of 82 questionnaires were sent out in this study, and 80 were effectively received, with s a recovery rate of 97.6%. In 80 patients, there were 45 males and 35 females; 35 cases (43.75%) were ≤14 years; most of the patients had flame and thermal burns; 33 patients (41.25%), 21 patients (26.25%), and 26 patients (32.50%) had moderate, severe, and extremely severe burns, respectively; and only 3 patients (3.75%) had no health insurance. In 80 family members of patients, 34 (42.50%) were males and 46 (57.50%) were females; 62.50% in the family members of patients were concentrated between 18 and 45 years old; and 12 family members of patients had experience of accompanying in intensive care isolation wards, accounting for 15.00%. The total CCFNI score of the family members was (141±14) points, and the scores of AS, PS, IS, CS, and SS were (3.77±0.23), (3.43±0.37), (3.53±0.34), (2.50±0.59), and (2.69±0.45) points, respectively. The top five items of the psychological needs of family members of patients were concentrated in three factors (AS, PS, and IS), and the item "ensuring that patients receive the best treatment" ranked the first, with a score of (3.99±0.11) points. There were significant differences on the CCFNI total scores of patients with different age, total burns area, and severity of burns and of their family members with different gender, education level, and whether or not experience of accompanying in intensive care isolation unit (F=4.378, 5.481, 5.913, t=4.027, 14.339, 7.265, P<0.05 or P<0.01). Multiple linear regression analysis showed that the patient's age (≤14, 15-45 years) and total burn area (11%-30%, 31%-49%, ≥50% TBSA) and the patient's family members' gender, educational level, experience of accompanying in intensive care isolation unit could affect the psychological needs of family members of patients (t=3.133, 2.260, 2.297, 2.433, 3.015, 2.200, 2.102, 2.463, P<0.05 or P<0.01). There was statistically significant difference in AS score of the patients' family members with different age (F=4.390, P<0.05). There were significant differences in both IS and AS scores of the patients' family members of patients with different burn area (F=5.042, 3.131, P<0.05 or P<0.01). The AS score of the patients' family members with experience of accompanying in intensive care isolation unit was significantly lower than those without (t=-1.040, P<0.05). The SS score of the patients' family members with college education or above was significantly higher than those with high school (technical secondary school) or below (t=0.657, P<0.05). The IS score of the patients' family members with college education or above was significantly lower than those with high school (technical secondary school) or below (t=-1.438, P<0.05). The SS score of male family members of patients was significantly lower than those of female patients (t=4.149, P<0.05). Conclusions: The family members of burn patients in semi-closed ward have the most urgent need to ensure the patients receive the best treatment. Patients' age, total burn area, and their family members' gender, education level, experience of accompanying in intensive care isolation unit are the main factors affecting the psychological needs of family members of patients.

Kynurenine 3-monooxygenase upregulates pluripotent genes through β-catenin and promotes triple-negative breast cancer progression

Background

Triple-negative breast cancer (TNBC) is aggressive and has a poor prognosis. Kynurenine 3-monooxygenase (KMO), a crucial kynurenine metabolic enzyme, is involved in inflammation, immune response and tumorigenesis. We aimed to study the role of KMO in TNBC.

Methods

KMO alteration and expression data from public databases were analyzed. KMO expression levels in TNBC samples were analyzed using immunohistochemistry. Knockdown of KMO in TNBC cells was achieved by RNAi and CRISPR/Cas9. KMO functions were examined by MTT, colony-forming, transwell migration/invasion, and mammosphere assays. The molecular events were analyzed by cDNA microarrays, Western blot, quantitative real-time PCR and luciferase reporter assays. Tumor growth and metastasis were detected by orthotopic xenograft and tail vein metastasis mouse models, respectively.

Findings

KMO was amplified and associated with worse survival in breast cancer patients. KMO expression levels were higher in TNBC tumors compared to adjacent normal mammary tissues. In vitro ectopic KMO expression increased cell growth, colony and mammosphere formation, migration, invasion as well as mesenchymal marker expression levels in TNBC cells. In addition, KMO increased pluripotent gene expression levels and promoter activities in vitro. Mechanistically, KMO was associated with β-catenin and prevented β-catenin degradation, thereby enhancing the transcription of pluripotent genes. KMO knockdown suppressed tumor growth and the expression levels of β-catenin, CD44 and Nanog. Furthermore, mutant KMO (known with suppressed enzymatic activity) could still promote TNBC cell migration/invasion. Importantly, mice bearing CRISPR KMO-knockdown TNBC tumors showed decreased lung metastasis and prolonged survival.

Interpretation

KMO regulates pluripotent genes via β-catenin and plays an oncogenic role in TNBC progression.

[Advance on the infectivity of SARS-CoV-2 infection at different stages]

The studies on infectiousness of person infected with SARS-CoV-2 at different stages of illness are an important basis for making effective prevention and control measures such as investigating the infectious source, determining the scope of close contacts and the timing of case isolation. This review discusses the infectiousness of cases infected with SARS-CoV-2 in the incubation period, symptomatic period and convalescent period by reviewing national and international literatures, technical and professional guidelines. Existing researches suggest that the infectious viruses could be isolated at the end of the incubation period as well as since illness onset, and viral load in upper respiratory tract swabs reached the peak on day 4-6 after illness onset and thereafter began to decline, implying the infectiousness was relatively strong at the end of incubation period and within one week after illness onset. Although there were a few cases who tested positive for SARS-CoV-2 after recovery, no evidence was found to indicate these cases can cause the transmission.

[Effects on learning and memory and mitochondrial energy metabolism in hippocampus of mice by subacute exposure to n-hexane]

Objective: To study the effects on learning and memory, mitochondrial energy metabolism and ATPase activity of hippocampus in mice with subacute exposure to n-hexane. Methods: The SPF 40 Kunming mice were randomly divided into low, middle and high dose groups and control groups according to different dosages. Each group consisted of 10 mice. The mice were given n-hexane by gavage, the mice in the low, middle and high dose groups were given 0.2 ml/d of n-hexane at concentrations of 500, 1000 and 2000 mg/kg respectively, while the mice in the control group were given 0.2 ml/d of cooking oil once a day for 28 days. The y-type maze test, the activity of ATP Enzyme, mitochondrial respiratory chain enzyme complex Ⅰ-IV, the mrna of mitochondrial fusion gene (MFn1, Mfn2) and fission gene (FIs1) in brain tissues were performed. Results: Except for the wrong reaction times of low-dose exposure group in the first test, there existed significantly different in the first and second Y-maze tests in exposure groups and control group (P<0.05) ; in low, middle and high-dose group, the Na(+)-K(+)-ATPase activities were (8.27±2.65) , (5.38±1.55) , (3.55±1.69) μmol/gprot/h, and Ca(2+)-Mg(2+)-ATPase activities were (10.32±2.96) , (7.19±1.94) and (4.49±1.33) μmol/gprot/h, respectively. Compared with those in control group, the activities of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase decreased significantly in middle-dose group and high-dose group (P<0.05) . Compared with those in control group, the activities of mitochondrial respiratory chain enzyme complex I-IV in each dose group were significantly decreased (P<0.05) . The expressions of Mfn1mRNA and Mfn2mRNA in each dose group was significantly lower than those in control group (P<0.05) . Conclusion: Subacute exposure to n-hexane can result in the decrease of activities of mitochondrial respiratory chain enzyme complex in hippocampus of mice, which may lead to the disorder of mitochondrial energy metabolism by the decrease of ATPase activity and the imbalance of mitochondrial fusion-division, which must be one of the mechanisms of impairment of learning and memory of mice induced by n-hexane.

[Long-term oncological outcomes of laparoscopic versus abdominal surgery in stage Ⅰa1 （LVSI+）-Ⅰb1 cervical cancer patients with different tumor size: a big database in China]

Objective: To compare the long-term oncological outcomes between laparoscopic and abdominal surgery in stage Ⅰa1 （lymph-vascular space invasion-positive, LVSI⁺）- Ⅰb1 cervical cancer patients with different tumor sizes. Methods: Based on the Big Database of Clinical Diagnosis and Treatment of Cervical Cancer in China (1538 project database), patients with stage Ⅰa1 （LVSI⁺）-Ⅰb1 cervical cancer who treated by laparoscopic or abdominal surgery were included. The 5-year overall survival (OS) and 5-year disease-free survival (DFS) between the two surgical approaches were compared under 1∶1 propensity score matching (PSM) in different tumor diameter stratification. Results: (1) A total of 4 891 patients with stage Ⅰa1 （LVSI⁺）-Ⅰb1 cervical cancer who underwent laparoscopy or laparotomy from January 1, 2009 to December 31, 2016 were included in the 1538 project database. Among them, 1 926 cases in the laparoscopic group and 2 965 cases in the abdominal group. There were no difference in 5-year OS and 5-year DFS between the two groups before matching. Cox multivariate analysis suggested that laparoscopic surgery was associated with lower 5-year DFS (HR=1.367, 95%CI: 1.105-1.690, P=0.004). After 1∶1 PSM matching, 1 864 patients were included in each group, and there was no difference in 5-year OS between the two groups （94.1% vs 95.4%, P=0.151）. While, the inferior 5-year DFS was observed in the laparoscopic group (89.0% vs 92.3%, P=0.004). And the laparoscopic surgery was associated with lower 5-year DFS (HR=1.420, 95%CI: 1.109-1.818, P=0.006). (2) In stratification analysis of different tumor sizes, and there were no difference in 5-year OS and 5-year DFS between the laparoscopic group and abdominal group in tumor size ≤1 cm, >1-2 cm and >2-3 cm stratification (all P>0.05). Cox multivariate analysis showed that laparoscopic surgery were not related to 5-year OS and 5-year DFS (P>0.05). In the stratification of tumor size >3-4 cm, there was no difference in 5-year OS between the two groups (P>0.05). The 5-year DFS in the laparoscopic group was worse than that in the abdominal group (75.7% vs 85.8%, P=0.025). Cox multivariate analysis suggested that laparoscopic surgery was associated with lower 5-year DFS (HR=1.705, 95%CI: 1.088-2.674, P=0.020). Conclusions: For patients with stage Ⅰa1 （LVSI⁺）-Ⅰb1 cervical cancer, laparoscopic surgery is associated with lower 5-year DFS, and the adverse effect of laparoscopic surgery on oncology prognosis is mainly reflected in patients with tumor size >3-4 cm. For patients with tumor sizes ≤1 cm, >1-2 cm and >2-3 cm, there are no difference in oncological prognosis between the two surgical approaches.

Long noncoding RNA SNHG8 promotes the proliferation of osteosarcoma cells by downregulating miR-542-3p

Small nucleolar RNA host genes (SNHGs) as a subset of long noncoding RNAs (lncRNAs) have critical roles in the pathogenesis of multiple malignancies, however, the role and molecular mechanisms of lncRNA SNHG8 in osteosarcoma (OS) remain unclear. In the present study, the correlation of SNHG8 or miR-542-3p with clinicopathological elements and prognosis in OS patents was estimated by TCGA cohort. Cell viability and invasion were assessed by MTT and Transwell assays. The interplay between SNHG8 and miR-542-3p was affirmed by a luciferase report assay. The effects of SNHG8 on miR-542-3p expression were examined in MG-63 and SW-1353 cells by qRT-PCR analysis. The results showed that incremental expression of SNHG8 or reduced expression of miR-542-3p was related to poor survival and tumor recurrence in OS patients. Overexpressing SNHG8 accelerated the growth and invasion of MG-63 cells, but silencing SNHG8 harbored an opposite effect in SW-1353 cells. Additionally, SNHG8 could negatively regulate miR-542-3p expression and bind with miR-542-3p, which attenuated SNHG8 induced cell proliferation. Taken together, these findings indicate that lncRNA SNHG8 promotes the proliferation of OS cells by downregulating miR-542-3p.

Abstract 6468: Prognostic genomic alterations associated with recurrence after primary therapy for patients with luminal B breast cancer

Purpose: Luminal type breast cancers account for the most common subtypes of breast cancers, among which luminal B subtype is relatively faster tumor growing and confers substantial risk of recurrence after primary treatment despite adjuvant endocrine therapy. Understanding the molecular alterations underlying the poorer survival outcome for luminal B tumors represents an unmet medical need.

Experimental design: The archival samples of 16 recurrences within 5 years, 3 recurrences between 5-10 years and 24 non-recurrence tumor tissues from luminal B breast cancer patients were retrieved. Genomic alterations of these 43 breast cancer samples were detected using deep next-generation sequencing of a 440-gene panel. The mRNA levels of candidate genes in breast cancer patients were analyzed from The Cancer Genome Atlas (TCGA) database.

Results: Overall, genomic alterations were found in 340 genes, including single nucleotide variants and copy number variation. Comparing to the non-recurrence tumors, NUP98 (31.3%), MAPK4 (18.8%), PTEN (18.8%), PER1 (18.8%) and TRIP11 (18.8%) showed higher population frequency in the recurrence tumors, and IGF2R (50.0%), PIM1 (45.8%) and ROS1 (37.5%) were dominate in the non-recurrence tumors. After a validation with the public clinical dataset, we identified three potential prognostic biomarkers, including NUP98, PER1, and TRIP11. We observed missense mutation or copy number deletion of NUP98, PER1 and TRIP11 in early recurrence tumors. Data from TCGA database exhibited patients with breast cancer harbored lower NUP98, PER1 and TRIP11 transcripts levels. Notably, lower NUP98, PER1 and TRIP11 expression levels correlated with worse recurrence-free survival in luminal B breast cancer. Interestingly, based on algorithm for visualization of protein interaction network, we found these 3 genes were all involved in androgen receptor signaling network.

Conclusion: Our study identified NUP98, PER1, and TRIP11 which potentially served as biomarkers to predict recurrence in luminal B breast cancer. Further research is required to understand the association between genomic alterations and androgen receptor signaling as well as its clinical impact.

Citation Format: Chun-Yu Liu, Ji-Lin Chen, Yi-Ting Yang, Yi-Fang Tsai, Ta-Chung Chao, Kien Thiam Tan, Wan-Lun Wang, Pei-Ju Lien, Shu-Jen Chen, Ling-Ming Tseng. Prognostic genomic alterations associated with recurrence after primary therapy for patients with luminal B breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6468.

Effects of fine particulate PM2.5 on emphysema of mice via regulating FOXO3A/BIM axis

This study aims to investigate the role of PM_2.5 exposure in inducing apoptosis of alveolar epithelial cells and thereafter emphysema in mice, and the underlying mechanism. PM_2.5 exposure model in mice was constructed. Lung tissues were harvested from healthy mice and model mice for hematoxylin and eosin (H&E) staining. Protein levels of Forkhead box O3 (FOXO3A) and BIM in lung tissues were detected by Western blot. Subsequently, A549 cells were induced with increased doses of PM_2.5, followed by determination of relative levels of FOXO3A, BIM (Bcl-2 interacting mediator of cell death) and clv-caspase3. Apoptosis in PM_2.5-exposed A549 cells was assessed. Chromatin immunoprecipitation (ChIP) assay was conducted to uncover the interaction between FOXO3A and BIM. Finally, regulatory effects of FOXO3A/BIM on apoptosis of A549 cells were determined. PM_2.5 exposure resulted in expansion of alveolar spatial structure and decline of lung function, thus leading to emphysema in mice. Protein levels of FOXO3A and BIM were markedly upregulated in lungs of model mice. Relative levels of FOXO3A, BIM and clv-caspase3 were enhanced in PM_2.5 -exposed A549 cells, which were reversed by transfection of si-FOXO3A. ChIP assay confirmed that FOXO3A was able to regulate BIM transcription through binding its promoter regions. Importantly, regulatory effects of FOXO3A on apoptosis of PM_2.5 -exposed A549 cells were partially reversed by overexpression of BIM. PM_2.5 exposure leads to upregulation of FOXO3A, which triggers BIM transcription, thus inducing apoptosis of alveolar epithelial cells and emphysema in mice.

Multivariate-t linear mixed models with censored responses, intermittent missing values and heavy tails

Multivariate longitudinal data arisen in medical studies often exhibit complex features such as censored responses, intermittent missing values, and atypical or outlying observations. The multivariate-t linear mixed model (MtLMM) has been recognized as a powerful tool for robust modeling of multivariate longitudinal data in the presence of potential outliers or fat-tailed noises. This paper presents a generalization of MtLMM, called the MtLMM-CM, to properly adjust for censorship due to detection limits of the assay and missingness embodied within multiple outcome variables recorded at irregular occasions. An expectation conditional maximization either (ECME) algorithm is developed to compute parameter estimates using the maximum likelihood (ML) approach. The asymptotic standard errors of the ML estimators of fixed effects are obtained by inverting the empirical information matrix according to Louis' method. The techniques for the estimation of random effects and imputation of missing responses are also investigated. The proposed methodology is illustrated on two real-world examples from HIV-AIDS studies and a simulation study under a variety of scenarios.

[The prevalence and relationship between laryngopharyngeal reflux disease, anxiety and depression in otolaryngology outpatients]

Objective: To obtain the prevalence laryngopharyngeal reflux disease (LPRD), anxiety and depression in otorhinolaryngology outpatients and to explore the role of mental and psychological factors (anxiety and depression) in their pathogenesis. Methods: A questionnaire survey of reflux symptom index(RSI) scale and hospital anxiety and depression (HAD) scale were used to report 1 111 cases of outpatients in Department of Otorhinolaryngology Head and Neck Surgery, Peking University People's Hospital, from July 2017 to June 2018 (486 males, 625 females, age of 18-96 years old, median age of 38[30,53] years old) and to obtain the prevalence of LPRD, anxiety and depression. RSI-positive patients were selected in the case group, and RSI-negative patients were selected in the control group. The differences in HAD scores between the two groups were compared, and the risk factors of laryngopharyngeal reflux were analyzed. Statistical analysis was performed using SPSS 20.0 software. Results: There were 151 cases in the case group and 960 cases in the control group. The prevalence of LPRD was 13.59% (151/1 111).There was no significant difference in the prevalence of LPRD between different genders (P>0.05). The prevalence rate was the highest in the 18-40 age group, and the difference in the prevalence of all age groups (18~ 40 years old; 41-65 years old; >65 years old) was statistically significant (P<0.05). The prevalence of LPRD among smokers and non-drinkers was higher than that of non-smokers and non-drinkers and the prevalence of the two groups was statistically significant (P<0.05). The most common symptoms of the RSI scale were pharyngeal foreign body sensation (92.72%,140/151), persistent clearing throat (88.74%,124/151), excessive sputum or nasal reflux (82.12%, 124/151). There were significant statistical differences between the two groups (P<0.05). Ninty-one patients with anxiety, the prevalence was 8.19%(91/1 111); 76 patients with depression, the prevalence was 6.84%(76/1 111).Among the LPRD patients, the hospital anxiety scale scored 29.14% (44/151), and the hospital depression scale scored 17.22% (26/151). The scores of anxiety symptoms and depressive symptoms in the LPRD group were higher than those in the non-LPRD group. The above scores were statistically significant (P<0.05). Logistic regression analysis showed that smoking, anxiety and symptoms of gastroesophageal reflux disease were independent risk factors for laryngopharyngeal reflux. Conclusions: The prevalences of LPRD, anxiety and depression in the otorhinolaryngology clinic are 13.59%, 8.19% and 6.84%, respectively. Among patients with laryngopharyngeal reflux, the prevalence of anxiety is 29.14%, and the prevalence of depression is 17.22%. Age, smoking, drinking, alcohol consumption, education level, course of disease, symptoms of gastroesophageal reflux disease, pharyngeal foreign body sensation, etc. are related to LPRD. Mental factors (anxiety and depression) may play a role in LPRD. Smoking, anxiety symptoms and symptoms of gastroesophageal reflux disease are closely related to the incidence of LPRD.

[Preliminary application of transjugular intrahepatic portosystemic shunt in individualized treatment of patients with cirrhotic portal hypertension complicated with refractory ascites and variceal hemorrhage]

Objective: To investigate the feasibility, efficacy and safety of transjugular intrahepatic portosystemic shunt (TIPS) in the individualized treatment of patients with refractory ascites and variceal hemorrhage caused by portal hypertension. Methods: Prospective study of clinical data of 47 patients with portal hypertension and refractory ascites and variceal bleeding admitted to the Affiliated Hospital of Xuzhou Medical University from August 2017 to December 2018, 26 males and 21 females, aged 23-75 (52±14) years old. The Viabahn stent was used to control the diameter of the shunt and the preoperative interval of PPG after individualized TIPS was determined according to the preoperative liver function Child-Pugh classification. The PPG of the Child A and B patients was <10 mm Hg (1 mmHg=0.133 kPa), Child-Pugh C grade patients with postoperative PPG interval values of 12 to 15 mmHg. The success rate, hemostasis rate, ascites remission rate, and complication rate were recorded. Results: Forty-seven patients were with a success rate of 100%, and there was no surgically related fatal complications. The portal pressure gradients of patients with Child-Pugh A, B and Child-Pugh C were reduced from preoperative (22.5±5.4), (24.4±2.6) mm Hg to postoperative (8.8±2.5), (13.2±1.1) mm Hg (all P<0.05). All the patients were followed up for 6 to 24 months, with a median follow-up of 13 months. The success rate of hemostasis in patients with upper gastrointestinal bleeding was 93.5% (29/31), the remission rate of patients with refractory ascites was 14/16, the postoperative rebleeding rate was 6.5% (2/31), the incidence of hepatic encephalopathy was 8.5% (4/47), and the shunt disorder was 2.1% (1/47). Conclusion: The use of Viabahn stent for individualized TIPS in the treatment of portal hypertension with refractory ascites and variceal hemorrhage is feasible, and the clinical efficacy is affirmative, which can reduce the incidence of postoperative hepatic encephalopathy and shunt dysfunction.

[Establishment and research of a New Zealand rabbit model of laryngopharyngeal reflux]

Objective: To establish a New Zealand rabbit animal model of laryngopharyngeal reflux disease (LPRD) using esophageal balloon together with metal internal stent dilation and to investigate the changes of mucosa. Methods: 20 New Zealand rabbits were randomly divided into experimental group and control group, with 10 in each group. Balloon dilatation and metal internal stent dilation were carried out in experimental group to reproduce the animal model of LPRD.The middle of balloon was placed at the lower esophageal sphincter (LES) while the stent was placed at the upper esophageal sphincter (UES). The guide wire was placed in the control group, but the balloon was not expanded and the stent was not placed. The general condition, pH value of hypopharynx, laryngeal histopathology and changes of pepsin content of New Zealand rabbits were observed regularly. The difference between experimental group and control group was compared. Results: The 24-hour Dx-pH monitoring results showed that the number of reflux episodes(20.0[9.5, 35.0], 13.0[6.5, 22.0]), and the percent time below pH 5.5 (1.36%[0.60%, 4.57%], 1.36%[0.43%, 2.77%]) in the experimental group at the 2nd and 4th week were significantly different from those in the control group (0[0,3.0], 1.0[0.5, 3.8]; 0[0, 0.01%], 0[0, 0], respectively, all P<0.01), suggesting that the experimental group New Zealand rabbits developed LPRD. Compared with the control group under microscope, lymphocytes infiltration and submucosal gland hyperplasia increased in the mucosa of the throat of the experimental group. The results of pepsin immunohistochemical staining between the two groups were statistically significant (P=0.014). Conclusion: The use of balloon dilatation of the LES combined with metal stent dilatation of the UES can successfully establish a laryngopharyngeal reflux model, and lesions in the throat tissue can be observed.

[Trend in proportion and clinicopathological characteristics of young women with stage Ⅰa2 to Ⅱa2 cervical cancer]

Objective: To analyze the 13 years trend in proportion, risks factors and clinicopathological characteristics of young women with stage Ⅰa2 to Ⅱa2 cervical cancer by using multi-center data of cervical cancer in China. Methods: The clinicopathological data of 46 313 patients with cervical cancer treated from 37 hospitals in China were obtained from January 2004 to December 2016. Using clinical and pathologic data, each patient's stage was reclassified by the 2018 International Federation of Gynecology and Obstetrics (FIGO) staging system. A total of 19 041 patients were selected according to the following criteria: FIGO stage Ⅰa2 to Ⅱa2, underwent type B or C radical hysterectomy and pelvic lymphadenectomy. All the patients were divided into two groups: the study group of 1 888 patients aged 35 years or younger and the control group of 17 153 patients aged over 35 years. The 13 years trend in proportion of young women with stage Ⅰa2 to Ⅱa2 cervical cancer, risks factors and clinicopathological characteristics of two groups were retrospectively analyzed. Results: (1) The total number of hospitalized patients with stage Ⅰa2 to Ⅱa2 cervical cancer increased annually. However, a downward trend of patients aged 35 years or younger was observed (P<0.01) . The constituent ratio of patients aged 35 years or younger was significantly greater during 2004-2010 than that during 2011-2016 [12.6% (820/6 484) and 8.5% (1 068/12 557) , respectively; χ(2)=82.101, P<0.01]. (2) Compared with patients aged over 35 years, patients aged 35 years or younger had an earlier age at menarche, a later age at marriage, lesser gravida and parity (all P<0.01). The positive rate of high-risk HPV infection was not statistically different between two groups (all P>0.05). (3) The proportions of stage Ⅰ, exophytic type and non-squamous histological type in patients aged 35 years or younger were clearly higher than those in patients aged over 35 years (83.4% vs 68.5%, P<0.01; 63.2% vs 56.2%, P<0.01; 13.9% vs 12.0%, P<0.05, respectively). Whereas the poor differentiation ratios of the two groups had no statistical significance (P>0.05). (4) As for the postoperative pathological risk factors, the rate of surgical margin involvement in patients aged 35 years or younger was lower than that aged over 35 years (1.1% vs 1.8%, P<0.05), and the rate of depth of stromal invasion >1/2 in patients aged 35 years or younger was lower than that in patients aged over 35 years (40.1% vs 50.9%, P<0.01). In addition, there were no significant difference in parametrial margin involvement, tumor size and lymph vascular space invasion between two groups (all P>0.05). Conclusions: The trend in proportion among hospitalized patients for stage Ⅰa2 to Ⅱa2 cervical cancer in young women is decreasing yearly. Compared with cervical cancer in middle-aged and elderly women, cervical cancer in young women have an earlier age at menarche, a higher proportion of stage Ⅰ patients and non-squamous histological type. In terms of the postoperative pathological risk factors, the rate of surgical margin involvement and depth of stromal invasion >1/2 in young women with cervical cancer are lower than in middle-aged and elderly women.

Abstract 1711: Kynurenine 3-monooxygenase (KMO) acts as a novel oncoprotein in triple negative breast cancer

Purpose: Tryptophan-kynurenine pathway involves in inflammation, immune response and tumorigenesis, in which kynurenine 3-monooxygenase (KMO), an outer mitochondrial membrane protein, mediating kynurenine metabolism. Previous studies indicated KMO showed increased activity in breast cancer. Triple-negative breast cancer (TNBC) tumors exhibited elevated levels of tryptophan metabolites compared to estrogen receptor positive breast cancers. We aimed to study the role of KMO in human TNBC.

Experimental design: The gene alterations and transcripts of enzymes in kynurenine metabolism were analyzed from The Cancer Genome Atlas (TCGA) database. Immunohistochemical staining for KMO was performed and a H-score was assigned to quantify protein expression. Epithelial-mesenchymal transition (EMT) phenotypes were examined by transwell assay and EMT markers expressions. Stemness properties were assessed by mammosphere assay and pluripotent genes expressions. The molecular events were analyzed by Western blot, quantitative real-time PCR and luciferase reporter assay. Tumor growth and metastasis were conducted in nude mice and NOD-SCID mice by subcutaneous and tail vein injection respectively.

Results: TCGA databases showed KMO but not KYNU and KAT2 was amplified in breast cancer. Both the data from TCGA and our in-house IHC-based tissue-microarray exhibited increased KMO expression in TNBC compared to normal tissue. In vitro, overexpression of KMO in TNBC cells resulted in increased cell growth and colony formation. The abilities migration and invasion as well as EMT markers expressions of TNBC cells were elevated by KMO overexpression. In addition, KMO increased mammosphere formation, pluripotent genes expressions and promoter activities. However, inhibition of KMO enzymatic activity by KMO inhibitors did not affect cancer progression or mitochondrial respiration of TNBC cells. KMO upregulated β-catenin, the upstream regulator of pluripotent genes, CD44 and Nanog expressions. Mechanistically, data showed KMO expressed in both cytosol and nuclear fractions and was associated with β-catenin. KMO enhanced pluripotent genes expressions through β-catenin upregulation. Importantly, KMO knockdown suppressed tumor growth and expressions of β-catenin, CD44 and Nanog in TNBC tumors. Moreover, KMO knockout significantly decreased lung metastasis in vivo.

Conclusion: Our data indicated KMO can play an oncogenic role in TNBC, acting as a novel regulator of pluripotent genes via β-catenin and promoted TNBC progression.

Citation Format: Chun-Yu Liu, Tzu-Ting Huang, Ji-Lin Chen, Chia-Han Lee, Wan-Lun Wang, Ka-Yi Lau, Chun-Teng Huang, Pei-Yi Chu, Hsin-Chen Lee, Ling-Ming Tseng. Kynurenine 3-monooxygenase (KMO) acts as a novel oncoprotein in triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1711.

[The role of PDK1 in the transition of endothelial to hematopoietic cells]

目的

研究磷酸肌醇依赖性激酶1（PDK1）在内皮细胞向造血细胞转化阶段对造血干细胞（HSC）发生的影响。

方法

应用Vec-Cre在内皮细胞中特异性敲除PDK1基因，取对照组PDK1^fl/fl、PDK1^fl/+小鼠及敲除组Vec-Cre；PDK1^fl/fl小鼠胚胎的主动脉-性腺-中肾区（AGM区）细胞进行集落形成实验，检测PDK1基因对造血祖细胞功能的影响；取对照组和敲除组AGM区细胞行移植实验，检测PDK1对HSC功能的影响；取对照组和敲除组AGM区细胞，通过流式细胞术检测PDK1对能够向造血转化的CD31⁺c-Kit^high细胞群比例、细胞周期及细胞凋亡的影响；分选对照组和敲除组AGM区CD31⁺c-Kit^high细胞群，通过Real-time PCR检测PDK1对内皮向造血转换相关的转录因子（RUNX1、P2-RUNX1、GATA2）的影响。

结果

PDK1敲除后，造血祖细胞形成的克隆形态变小，数目减少[敲除组CFU-GM为（24±5）个/ee，对照组为（62±1）个/ee，P=0.001]；破坏了造血干细胞重建造血及多向分化的能力（敲除组移植5只，0只重建，对照组移植7只，5只重建，P=0.001）；AGM区CD31⁺c-Kit^high比例降低[敲除组CD31⁺c-Kit^high比例为（0.145±0.017）%，对照组比例为（0.385±0.04）%，P=0.001]；并且AGM区由内皮细胞向造血细胞转换的关键转录因子表达下降，但对CD31⁺c-Kit^high细胞的增殖和凋亡无明显影响。

结论

在内皮细胞中特异敲除PDK1基因，导致具有向造血转化的内皮细胞群比例降低，影响了HSC的发生，破坏了HSC重建造血的能力。

[Effectiveness evaluation between enhanced recovery after surgery and traditional treatment in unilateral total knee arthroplasty]

Objective: To investigate the clinical effect of enhanced recovery after surgery (ERAS) in unilateral total knee arthroplasty (TKA). Methods: Retrospective analysis of 98 patients received unilateral TKA from September 2015 to September 2016 in the Orthopaedic Departmentof Affiliated Hospital of Logistics University of Chinese People's Armed Police Forces.Of the patients, 52 cases were treated by traditional operation (routine group) and the other 46 cases were treated with ERAS concept (ERAS group). The following data were gathered and statistically analyzed between the groups: gender, age, body mass index, preoperative hemoglobin, preoperative visual analogue scale (VAS) score, postoperative visible blood loss, postoperative hemoglobin at 24 hour after operation, blood transfusion rate, postoperative VAS score, length of hospital stay, the satisfaction rate, preoperative and 1 and 6 months postoperative evaluation with hospital for special surgery knee score (HSS), postoperative range of motion (ROM) of knees after 2 weeks, 1 month and 6 months of surgery, incidence rate of complications after surgery.Data between groups were analyzed with one-factor analysis of variance or chi-square test. Results: There was no significant difference in preoperative data between two groups.Postoperative visible blood loss of ERAS group was significantly lower than that in routine group[(224±59) vs (361±70) ml, t=4.723, P<0.01]; postoperative hemoglobin after 24 hours in ERAS group was significantly higher than that in routine group[(109±8) vs (96±10) g/L, t=-3.297, P=0.004]; blood transfusion rate of ERAS group was significantly lower than that in routine group[6.5 %(3/46) vs 46.2%(24/52), χ(2)=19.207, P<0.01]; the 12-hour and 48-hour postoperative VAS scores in ERAS groups were both significantly lower than those in routine group (t=3.708, 3.894, both P<0.05); length of hospital stay in ERAS group was significantly shorter than that in routine group[(6.8±1.2) vs (13.1±2.6) d, t=6.924, P<0.01]; HSS scores of ERAS groups at 1 month and 6 months after surgery were both significantly higher than those in routine group (t=-3.677, -3.594, both P<0.05); knees ROM in ERAS group at 2 weeks and 1 month after surgery were both significantly higher than those in routine group (t=-4.628, -4.442, both P<0.05); the rate of postoperative nausea vomiting in ERAS group was significantly lower than that in routine group[13.0%(6/46) vs 48.1%(25/52), χ(2)=13.852, P=0.002]. VAS score at 1 month after surgery, knees ROM at 6 months after surgery and the satisfaction rate were all comparable between the two groups (t=0.412, -1.026, χ(2)=3.695, all P>0.05). Conclusions: Condition of patients treated by unilateral TKA under ERAS model improves effectively during perioperative period when compared with routine treatment, patients have earlier rehabilitation and better experience in hospital and operation.

[Analyses of pathogenic factors and clinicopathological characteristics of vocal leukoplakia]

Objective: To investigate the pathogenic factors of vocal leukoplakia and its clinical and pathological features. Methods: Eighty-one patients with vocal cord leukoplakia who underwent surgery between February 2010 and December 2016 and 160 volunteers without pharyngeal symptoms designed as controls were included in this case control study. The clinicopathological characteristics of 81 patients were summarized and analyzed synthetically. Results: There was statistical significance in reflux symptom index(RSI), reflux finding score(RFS), smoking index, and drinking index between case group and control group(Z=-5.35, -4.82, -4.76, -2.44, P<0.05). The voice-using duration per day in case group was significantly longer than that of control group.There was no statistical significance in hospital anxiety and depression scale for anxiety(HADA) scores、hospital anxiety and depression scale for depression(HADD) scores between case group and control group(P>0.05). In 42 patients who received 24-hour dual probe pH monitoring the prevalence of pathologic LPR was 42.8%. In 81 patients, 39(48%)patients were pathologically diagnosed as squamous cell hyperplasia, 18(22%)patients as mild dysplasia, 12(15%)sides as moderate dysplasia , 10(12%)patients as severe dysplasia and 2(2%)patients as carcinoma in-situ. The average age of high-risk pathological vocal leukoplakia was significantly higher than that of low-risk leukoplakia(t=-2.73, P<0.01). The propotion of speckled leukoplakia in high-risk leukoplakia was significantly higher than that of low-risk leukoplakia(χ(2)=23.81, P<0.01). There was no statistical significance between high-risk leukoplakia and low-risk leukoplakia in the prevalence of pathologic LPR(P>0.05). The bilateral lesions, speckled leukoplakia were more likely to relapse(χ(2)=4.27, 12.17, P<0.05). The more serious the pathology, the more likely it was to relapse (Z=-2.168, P=0.03). There was no statistical significance between recurrence group and non-recurrence group in the prevalence of pathologic LPR(P>0.05). Conclusions: LPR, smoke constitute the risk factors of vocal cord leukoplakia. Drinking, voice abuse are related to vocal cord leukoplakia. Senile, speckled leukoplakia are more likely to be malignancy. A speckled leukoplakia, bilateral leukoplakia, severe pathological degree are important factors to predict recurrence.

Low-protein diet improves meat quality of growing and finishing pigs through changing lipid metabolism, fiber characteristics, and free amino acid profile of the muscle

The objective of the study was to investigate the effect of feeding reduced CP, AA-supplemented diets on meat quality in growing and finishing pigs as well as the related mechanism. In experiment 1, 18 growing pigs (36.5 kg BW) were assigned randomly and fed 1 of 3 corn-soybean meal diets containing either 18% CP (normal protein, NP), 15% CP (low protein, LP), or 12% CP (very low protein, VLP). In experiment 2, 18 finishing pigs (62.3 kg BW) were allotted randomly into 1 of the following diets: 16% CP (NP), 13% CP (LP), or 10% CP (VLP). In both experiments, the LP and VLP diets were supplemented with crystalline AA to achieve equal content of standardized ileal digestible lysine, methionine, threonine, and tryptophan. At the end of each experiment, all pigs were slaughtered to collect longissimus dorsi muscle (LM) samples. Samples were used for determining meat quality, intramuscular fat (IMF) content, fatty acid composition, free AA profile, and expression of genes for myosin heavy chain isoforms. Results showed that growing and finishing pigs fed the LP diets increased (P < 0.05) redness value of LM, while finishing pigs fed the LP and VLP diets decreased (P < 0.05) the shear force values. Compared with the NP diet, growing and finishing pigs fed lower CP diets had higher (P < 0.05) contents of IMF and MUFA, and lower (P < 0.05) contents of PUFA. Besides, higher (P < 0.05) expression levels of type I and/or IIa muscle fibers were observed in LP diet-fed growing and finishing pigs, and greater concentrations of taurine and tasty AA in VLP diet-fed growing and finishing pigs. Taken together, our results indicate that low-protein diets could positively affect meat quality of growing and finishing pigs, and likely through regulation of IMF content and fatty acid composition, fiber characteristics, and free AA profile in the muscle.

Abstract 4372: SET/PP2A/SHP-1/Lyn oncogenic signaling contributes to tumor aggressiveness in diffuse large B cell lymphoma

Purpose:

Diffuse large B-cell lymphoma (DLBCL) is aggressive non-Hodgkin lymphoma. It is a heterogeneous disease and is classified as germinal center B-cell like (GCB) and activated B-cell like (ABC) subtypes according to gene-expression profiling. The oncogenic pathways in DLBCL are potential targets for new therapies. In present study, the role and regulation of SET/PP2A/SHP-1/Lyn axis in DLBCL were investigated.

Experimental design: U2932, OCL-Ly3, OCI-Ly7, SU-DHL-6 and DB DLBCL cell lines were used for this study. TD-19, a novel SET/PP2A protein-protein interaction inhibitor, was used to address the molecular events of SET signaling. Cell viability was measured by MTT assay. The apoptotic cells were examined by PI/Annexin V staining and Western blotting. SHP-1, Lyn and pLyn were analyzed by immunohistochemistry on lymphoma tissue microarrays from DLBCL patients.

Results:

We first examined the effects of two different SET inhibitors, TD-19 that is a SET/PP2A protein protein interaction inhibitor, and FTY720 which is a sphingosine analogue that targets SET, on DLBCL cells. TD-19 and FTY720 significantly decreased cell viability and induced apoptosis. SET inhibition activated PP2A and SHP-1 by reducing pPP2AY307 and pSHP-1S591 and inactivated Lyn by decreasing pLynY396. Overexpression of SET rescued these molecular events, and promoted cell growth and migration. Interestingly, we observed the level of SET was declined by TD-19 and TFY720 treatment. We hypothesized Lyn might up-regulate SET expression. Overexpression of Lyn increased SET level, and was accompanied with phosphorylation of PP2A (pPP2AY307) and SHP-1 (pSHP-1S591). Lyn elevated cell growth and migration and suppressed PP2A and SHP-1 activities. Moreover, exogenous SET restored the FTY720- and TD-19-suppressed pSHP-1 and pLyn. Immunohistochemically, high SHP-1 level was linked to low pLyn level of patient with DLBCL and vice versa.

Conclusion: This study established the existence of positive feedback of SET/PP2A/SHP-1/Lyn axis in DLBCL cells, and targeting SET could disrupt this regulation.

Citation Format: Ji-Lin Chen, Wen-Chun Tsai, Tien-Yun Lan, Chun-Teng Huang, Pei-Yi Chu, Chia-Han Lee, Ka-Yi Lau, Wan-Lun Wang, Kuen-Feng Chen, Chung-Wai Shiau, Chun-Yu Liu. SET/PP2A/SHP-1/Lyn oncogenic signaling contributes to tumor aggressiveness in diffuse large B cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4372.

Abstract 4612: SET overexpression is associated with recurrence-free survival in patients with primary breast cancer receiving adjuvant tamoxifen treatment

Background:

Estrogen receptor (ER) positive breast cancer accounts for 70% of breast cancer. Tamoxifen, a selective ER modulator, remains an important hormone therapeutic agent for patients with ER positive breast cancer. A number of patients receiving adjuvant tamoxifen still experience recurrence in the long term. In current study we explored the clinical significance of four biomarkers including SET, CIP2A, PP2A and Akt in ER positive breast cancer patients receiving adjuvant tamoxifen.

Methods:

Specimens were from ER positive breast cancer patients treated with adjuvant tamoxifen for a median of duration of 54.8 months with documented outcomes. The median follow-up was 106 months. Immunohistochemical staining for SET, CIP2A, p-PP2A (Tyr 307), p-Akt were performed and a H-score was assigned to quantify protein expression. In silico analysis of gene expression was evaluated from the public database KM plotter (available at: http://kmplot.com/analysis/). Human ER positive breast cancer cell line MCF7 cells were used for in vitro studies. MTT assay, flow cytometry and Western blot were used to assess the cells properties. Estrogen response element (ERE)-dependent luciferase activity was assessed by co-transfection of SET-expressing or control plasmids and 3⊆ERE bearing reporter plasmids into MCF7 cells and stimulated with estrogen.

Results:

In 218 primary ER positive breast cancer patients treated with adjuvant tamoxifen, 17 (7.8%) suffered from recurrence or metastasis. Higher expressions of SET and CIP2A by IHC analysis were associated with poor recurrence-free survival (RFS). Multivariate analysis revealed SET was independently correlated with worse RFS (Hazard ratio=3.72, 95% confidence interval 1.26-10.94, p=0.017). In silico, KM-plotter analysis revealed higher gene (mRNA) expressions of SET, PPP2CA and

Akt1 significantly correlated with worse RFS in breast cancer patients receiving adjuvant tamoxifen therapy. Because SET appeared to be the most prognostic for RFS among the four markers, we next explored the biological role in vitro. Tamoxifen exerted anti-proliferation and apoptotic effects in a dose-dependent manner of MCF7 cells. SET overexpression reduced tamoxifen-induced anti-proliferation in MCF-7 cells, in association with upregulated p-ER, suggesting that SET may affect ER pathway via the serine/threonine kinase PP2A. SET drove luciferase activity in an ERE-dependent manner, and also enhanced estrogen-promoted luciferase activity.

Conclusions:

Protein SET is a prognostic biomarker in ER positive breast cancer patients treated with tamoxifen and may contribute to tamoxifen resistance by modulating ER signaling pathway.

Citation Format: Yu-Hsiang Huang, Pei-Yi Chu, Ji-Lin Chen, Chun-Teng Huang, Chia-Han Lee, Ka-Yi Lau, Wan-Lun Wang, Yu-Ling Wang, Pei-Ju Lien, Ling-Ming Tseng, Chun-Yu Liu. SET overexpression is associated with recurrence-free survival in patients with primary breast cancer receiving adjuvant tamoxifen treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4612.

Multivariate-$t$ nonlinear mixed models with application to censored multi-outcome AIDS studies

In multivariate longitudinal HIV/AIDS studies, multi-outcome repeated measures on each patient over time may contain outliers, and the viral loads are often subject to a upper or lower limit of detection depending on the quantification assays. In this article, we consider an extension of the multivariate nonlinear mixed-effects model by adopting a joint multivariate-$t$ distribution for random effects and within-subject errors and taking the censoring information of multiple responses into account. The proposed model is called the multivariate-$t$ nonlinear mixed-effects model with censored responses (MtNLMMC), allowing for analyzing multi-outcome longitudinal data exhibiting nonlinear growth patterns with censorship and fat-tailed behavior. Utilizing the Taylor-series linearization method, a pseudo-data version of expectation conditional maximization either (ECME) algorithm is developed for iteratively carrying out maximum likelihood estimation. We illustrate our techniques with two data examples from HIV/AIDS studies. Experimental results signify that the MtNLMMC performs favorably compared to its Gaussian analogue and some existing approaches.

Multivariate longitudinal data analysis with censored and intermittent missing responses

The multivariate linear mixed model (MLMM) has emerged as an important analytical tool for longitudinal data with multiple outcomes. However, the analysis of multivariate longitudinal data could be complicated by the presence of censored measurements because of a detection limit of the assay in combination with unavoidable missing values arising when subjects miss some of their scheduled visits intermittently. This paper presents a generalization of the MLMM approach, called the MLMM-CM, for a joint analysis of the multivariate longitudinal data with censored and intermittent missing responses. A computationally feasible expectation maximization-based procedure is developed to carry out maximum likelihood estimation within the MLMM-CM framework. Moreover, the asymptotic standard errors of fixed effects are explicitly obtained via the information-based method. We illustrate our methodology by using simulated data and a case study from an AIDS clinical trial. Experimental results reveal that the proposed method is able to provide more satisfactory performance as compared with the traditional MLMM approach.

Bayesian semiparametric modeling for HIV longitudinal data with censoring and skewness

In biomedical studies, the analysis of longitudinal data based on Gaussian assumptions is common practice. Nevertheless, more often than not, the observed responses are naturally skewed, rendering the use of symmetric mixed effects models inadequate. In addition, it is also common in clinical assays that the patient's responses are subject to some upper and/or lower quantification limit, depending on the diagnostic assays used for their detection. Furthermore, responses may also often present a nonlinear relation with some covariates, such as time. To address the aforementioned three issues, we consider a Bayesian semiparametric longitudinal censored model based on a combination of splines, wavelets, and the skew-normal distribution. Specifically, we focus on the use of splines to approximate the general mean, wavelets for modeling the individual subject trajectories, and on the skew-normal distribution for modeling the random effects. The newly developed method is illustrated through simulated data and real data concerning AIDS/HIV viral loads.