A machine learning case study to predict rare clinical event of interest: imbalanced data, interpretability, and practical considerations.

Accurate prediction of a rare and clinically important event following study treatment has been crucial in drug development. For instance, the rarity of an adverse event is often commensurate with the seriousness of medical consequences, and delayed detection of the rare adverse event can pose significant or even life-threatening health risks to patients. In this machine learning case study, we demonstrate with an example originated from a real clinical trial setting how to define and solve the rare clinical event prediction problem using machine learning in pharmaceutical industry. The unique contributions of this work include the proposal of a six-step investigation framework that facilitates the communication with non-technical stakeholders and the interpretation of the model performance in terms of practical consequences in the context of patient screenings for conducting a future clinical trial. In terms of machine learning methodology, for data splitting into the training and test sets, we adapt the rare-event stratified split approach (from scikit-learn) to further account for group splitting for multiple records of a patient simultaneously. To handle imbalanced data due to rare events in model training, the cost-sensitive learning approach is employed to give more weights to the minor class and the metrics precision together with recall are used to capture prediction performance instead of the raw accuracy rate. Finally, we demonstrate how to apply the state-of-the-art SHAP values to identify important risk factors to improve model interpretability.

Minimally invasive versus open ileal ureter with ileocystoplasty: comparative outcomes and 5-year experience.

PURPOSE: To present the experience of ileal ureter with ileocystoplasty (IUC), and compare the outcomes of IUC in minimally invasive procedures to open procedures. PATIENTS AND METHODS: From December 2017 to April 2023, twenty patients underwent IUC in open or minimally invasive (including laparoscopic and robotic) procedures. The baseline characteristics, perioperative data and follow-up outcomes were collected. Success was defined as relief of clinical symptoms, stable postoperative serum creatine and absence of radiographic obstruction. The perioperative and follow-up outcomes of open procedures and minimally invasive procedures were compared. RESULTS: The etiology included pelvic irradiation (14/20), urinary tuberculosis (3/20) and surgical injury (3/20). Bilateral ureter strictures were repaired in 15 cases. The surgeries conducted consisted of open procedures in 9 patients and minimally invasive procedures in 11 patients. Compared to open procedures, minimally invasive surgeries had less median estimated blood loss (EBL) (100 ml vs. 300 min, p = 0.010) and shorter postoperative hospitalization (27 d vs. 13 d, p = 0.004). Two patients in the open group experienced grade 3 complications (sigmoid fistula and acute cholecystitis in one patient, and pulmonary embolism in another patient). Over a median follow-up period of 20.1 months, the median bladder functional capacity was 300 ml, with a 100% success rate of IUC. CONCLUSION: IUC is feasible in both open and minimally invasive procedures, with acceptable complications and a high success rate. Minimally invasive procedures can have less EBL and shorter postoperative hospitalization than open procedure. However, prospective studies with larger groups and longer follow-up are needed.

Modified Ileal Conduit for Pelvic Lipomatosis: Technique Description and Outcome.

INTRODUCTION: To present the surgical technique and clinical outcomes of modified ileal conduit for pelvic lipomatosis (PL). METHODS: From 2020 to 2022, we prospectively enrolled 9 patients with PL undergoing modified ileal conduit. The patient characteristics, perioperative variables, and follow-up outcomes as well as the description of surgical technique were reported. RESULTS: All 9 patients successfully completed the operation. Two patients had perioperative complications of Clavien-Dindo grade I. The mean operation time and bleeding volumes were 253±51.4 min and 238.9±196.9 ml, with a mean postoperative follow-up time of 13.0±5.6 months. The postoperative 3-month and 1-year creatinine values were significantly decreased versus the preoperative (P=0.006 and P=0.024). The postoperative 3-month and 1-year eGFR values were significantly increased comapred with those before operation (P=0.0002 and P=0.018). The separation value of left renal pelvis collection system after operation were significantly reduced compared with preoperative evaluation (P=0.023 at 3 month and P=0.042 at 1 year) and so was the right side (P=0.019 and P=0.023). CONCLUSION: Modified ileal conduit is safe and feasible for PL. A large sample cohort with long-term follow-up is needed to evaluate the clinical outcomes of PL.

Doubly adaptive biased coin design to improve Bayesian clinical trials with time-to-event endpoints.

Clinical trialists often face the challenge of balancing scientific questions with other design features, such as improving efficiency, minimizing exposure to inferior treatments, and simultaneously comparing multiple treatments. While Bayesian response adaptive randomization (RAR) is a popular and effective method for achieving these objectives, it is known to have large variability and a lack of explicit theoretical results, making its use in clinical trials a subject of concern. It is desirable to propose a design that targets the same allocation proportion as Bayesian RAR and achieves the above objectives but addresses the concerns over Bayesian RAR. We propose the frequentist doubly adaptive biased coin designs (DBCD) targeting ethical allocation proportions from the Bayesian framework to satisfy different objectives in clinical trials with time-to-event endpoints. We derive the theoretical properties of the proposed adaptive randomization design and show through comprehensive numerical simulations that it can achieve ethical objectives without sacrificing efficiency. Our combined theoretical and numerical results offer a strong foundation for the practical use of RAR in real clinical trials.

Minimally invasive ureteroplasty with lingual mucosal graft for complex ureteral stricture: analysis of surgical and patient-reported outcomes.

OBJECTIVE: To evaluate objective treatment efficacy and safety, and subjective patient-reported outcomes in patients with complex ureteral strictures (US) undergoing minimally invasive lingual mucosal graft ureteroplasty (LMGU). MATERIALS AND METHODS: We prospectively enrolled patients underwent robotic or laparoscopic LMGU between May 2020 and July 2022. Clinical success was defined as symptom-free and no radiographic evidence of re-obstruction. Patient-reported outcomes, including health-related quality of life (HRQoL), mental health status and oral health-related quality of life (OHRQoL), were longitudinally evaluated before surgery, 6 and 12 months postoperatively. RESULTS: Overall, 41 consecutive patients were included. All procedures were performed successfully with 32 patients in robotic approach and 9 in laparoscopic. Forty (97.56%) patients achieved clinical success during the median follow-up of 29 (range 15-41) months. Although patients with complex US experienced poor baseline HRQoL, there was a remarkable improvement following LMGU. Specifically, the 6-month and 12-month postoperative scores were significantly improved compared to the baseline (p < 0.05) in most domains. Twenty-eight (68.3%) and 31 (75.6%) patients had anxiety and depression symptoms before surgery, respectively. However, no significant decrease in the incidence of these symptoms was observed postoperatively. Moreover, there was no significant deterioration of OHRQoL at 6 months and 12 months postoperatively when compared to the baseline. CONCLUSIONS: LMGU is a safe and efficient procedure for complex ureteral reconstruction that significantly improves patient-reported HRQoL without compromising OHRQoL. Assessing patients' quality of life enables us to monitor postoperative recovery and progress, which should be considered as one of the criteria for surgical success.

Minimal-invasive ileal ureter replacement for the management of multiple ureteral polyps: the initial experience.

PURPOSE: To present our initial experience in the management of multiple ureteral polyps with robotic or laparoscopic ileal ureter replacement (IUR). METHODS: Eight consecutive patients diagnosed with multiple ureteral polyps underwent robotic or laparoscopic IUR between July 2019 and November 2022. Unilateral IUR was performed in 5 patients with polyps in the left (n = 3) or right (n = 2) side, and 3 patients with bilateral multiple polyps underwent bilateral IUR. Demographic characteristics, perioperative data and follow-up outcomes were prospectively collected. RESULTS: A cohort of 5 male and 3 female patients (11 ureters) with a mean age of 32.8 ± 11.3 years were included. Among these patients, 5 presented with recurrent flank pain, 1 had hematuria, and 2 were asymptomatic. Four patients experienced prior failed surgical interventions. The mean length of diseased ureter was 11.9 ± 4.7 cm, with more than 10 cm in eight sides. All procedures were performed successfully. The mean operation time was 319 ± 87.6 min with 3 patients who simultaneously underwent intraoperative ureteroscopy. The mean length of ileal graft was 23.8 ± 5.8 cm. During the mean follow-up of 20.4 ± 12.8 months, one major complication, specifically incision infection, and four minor complications, including urinary infection (n = 3) and metabolic acidosis (n = 1), were observed. All patients presented symptom-free, with improved/stabilized hydronephrosis and no signs of restenosis. CONCLUSION: Robotic or laparoscopic IUR is a feasible, safe, and effective surgical option for patients with long ureteral defects caused by multiple polyps.

Minimally invasive ureteroplasty with lingual mucosal graft for complex ureteral stricture: analysis of surgical and patient-reported outcomes

ABSTRACT Objective: To evaluate objective treatment efficacy and safety, and subjective patient-reported outcomes in patients with complex ureteral strictures (US) undergoing minimally invasive lingual mucosal graft ureteroplasty (LMGU). Materials and Methods: We prospectively enrolled patients underwent robotic or laparoscopic LMGU between May 2020 and July 2022. Clinical success was defined as symptom-free and no radiographic evidence of re-obstruction. Patient-reported outcomes, including health-related quality of life (HRQoL), mental health status and oral health-related quality of life (OHRQoL), were longitudinally evaluated before surgery, 6 and 12 months postoperatively. Results: Overall, 41 consecutive patients were included. All procedures were performed successfully with 32 patients in robotic approach and 9 in laparoscopic. Forty (97.56%) patients achieved clinical success during the median follow-up of 29 (range 15-41) months. Although patients with complex US experienced poor baseline HRQoL, there was a remarkable improvement following LMGU. Specifically, the 6-month and 12-month postoperative scores were significantly improved compared to the baseline (p < 0.05) in most domains. Twenty-eight (68.3%) and 31 (75.6%) patients had anxiety and depression symptoms before surgery, respectively. However, no significant decrease in the incidence of these symptoms was observed postoperatively. Moreover, there was no significant deterioration of OHRQoL at 6 months and 12 months postoperatively when compared to the baseline. Conclusions: LMGU is a safe and efficient procedure for complex ureteral reconstruction that significantly improves patient-reported HRQoL without compromising OHRQoL. Assessing patients' quality of life enables us to monitor postoperative recovery and progress, which should be considered as one of the criteria for surgical success.

Signaling pathways underlying TGF-ß mediated suppression of IL-12A gene expression in monocytes.

Transforming growth factor-ß (TGF-ß) is a pleiotropic cytokine essential for multiple biological processes, including the regulation of inflammatory and immune responses. One of the important functions of TGF-ß is the suppression of the proinflammatory cytokine interleukin-12 (IL-12), which is crucial for mounting an anti-tumorigenic response. Although the regulation of the IL-12p40 subunit (encoded by the IL-12B gene) of IL-12 has been extensively investigated, the knowledge of IL-12p35 (encoded by IL-12A gene) subunit regulation is relatively limited. This study investigates the molecular regulation of IL-12A by TGF-ß-activated signaling pathways in THP-1 monocytes. Our study identifies a complex regulation of IL-12A gene expression by TGF-ß, which involves multiple cellular signaling pathways, such as Smad2/3, NF-κB, p38 and JNK1/2. Pharmacological inhibition of NF-κB signaling decreased IL-12A expression, while blocking the Smad2/3 signaling pathway by overexpression of Smad7 and inhibiting JNK1/2 signaling with a pharmacological inhibitor, SP600125, increased its expression. The elucidated signaling pathways that regulate IL-12A gene expression potentially provide new therapeutic targets to increase IL-12 levels in the tumor microenvironment.

A New Systemic Disease Mouse Model for Glioblastoma Capable of Single-Tumour-Cell Detection.

BACKGROUND: Glioblastoma is characterised by extensive infiltration into the brain parenchyma, leading to inevitable tumor recurrence and therapeutic failure. Future treatments will need to target the specific biology of tumour recurrence, but our current understanding of the underlying mechanisms is limited. Significantly, there is a lack of available methods and models that are tailored to the examination of tumour recurrence. METHODS: NOD-SCID mice were orthotopically implanted with luciferase-labelled donor U87MG or MU20 glioblastoma cells. Four days later, an unlabelled recipient tumor was implanted on the contralateral side. The mice were euthanised at a humane end-point and tissue and blood samples were collected for ex vivo analyses. RESULTS: The ex vivo analyses of the firefly-labelled MU20 tumours displayed extensive invasion at the primary tumour margins, whereas the firefly-labelled U87MG tumours exhibited expansive phenotypes with no evident invasions at the tumour margins. Luciferase signals were detected in the contralateral unlabelled recipient tumours for both the U87MG and MU20 tumours compared to the non-implanted control brain. Remarkably, tumour cells were uniformly detected in all tissue samples of the supratentorial brain region compared to the control tissue, with single tumour cells detected in some tissue samples. Circulating tumour cells were also detected in the blood samples of most of the xenografted mice. Moreover, tumour cells were detected in the lungs of all of the mice, a probable event related to haematogenous dissemination. Similar results were obtained when the U87MG cells were alternatively labelled with gaussian luciferase. CONCLUSIONS: These findings describe a systemic disease model for glioblastoma which can be used to investigate recurrence biology and therapeutic efficacy towards recurrence.

Grain-growth Inhibitor with Three-section-sintering for Highly Dispersed Single-crystal NCM90 Cubes.

Single crystallization of LiNix Coy Mn1-x-y O2 (NCM) is currently an effective strategy to improve the cycling life of NCM cathode, owing to the reduced surface area and enhanced mechanical strength, but the application of single crystal NCM(SC-NCM) is being hindered by severe particle agglomeration and poor C-rate performance. Here, a strategy of three-section-sintering(TSS) with the presence of grain-growth inhibitor was proposed, in which, the TSS includes three sections of phase-formation, grain-growth and phase-preservation. While, the addition of MoO3 inhibits the grain growth and restrains the particle agglomeration. With the help of TSS and 1 mol % of MoO3 , highly dispersed surface Mo-doped SC-NCM(MSC-NCM) cubes are obtained with the average diameter of 1.3 µm. Benefiting from the surface Mo-doping and the reduced surface energy, the Li+ -migration preferred (1 0 4) crystalline facet is exposed as the dominant plane in MSC-NCM cubes, because of which, C-rate performance is significantly improved compared with the regular SC-NCM. Furthermore, this preparation strategy is compatible well with the current industrial production line, providing an easy way for the large-scale production of SC-NCM.

A New Era of Integration between Multiomics and Spatio-Temporal Analysis for the Translation of EMT towards Clinical Applications in Cancer.

Epithelial-mesenchymal transition (EMT) is crucial to metastasis by increasing cancer cell migration and invasion. At the cellular level, EMT-related morphological and functional changes are well established. At the molecular level, critical signaling pathways able to drive EMT have been described. Yet, the translation of EMT into efficient diagnostic methods and anti-metastatic therapies is still missing. This highlights a gap in our understanding of the precise mechanisms governing EMT. Here, we discuss evidence suggesting that overcoming this limitation requires the integration of multiple omics, a hitherto neglected strategy in the EMT field. More specifically, this work summarizes results that were independently obtained through epigenomics/transcriptomics while comprehensively reviewing the achievements of proteomics in cancer research. Additionally, we prospect gains to be obtained by applying spatio-temporal multiomics in the investigation of EMT-driven metastasis. Along with the development of more sensitive technologies, the integration of currently available omics, and a look at dynamic alterations that regulate EMT at the subcellular level will lead to a deeper understanding of this process. Further, considering the significance of EMT to cancer progression, this integrative strategy may enable the development of new and improved biomarkers and therapeutics capable of increasing the survival and quality of life of cancer patients.

Simultaneously targeting extracellular vesicle trafficking and TGF-ß receptor kinase activity blocks signaling hyperactivation and metastasis.

Metastasis is the leading cause of cancer-related deaths. Transforming growth factor beta (TGF-ß) signaling drives metastasis and is strongly enhanced during cancer progression. Yet, the use of on-target TGF-ß signaling inhibitors in the treatment of cancer patients remains unsuccessful, highlighting a gap in the understanding of TGF-ß biology that limits the establishment of efficient anti-metastatic therapies. Here, we show that TGF-ß signaling hyperactivation in breast cancer cells is required for metastasis and relies on increased small extracellular vesicle (sEV) secretion. Demonstrating sEV's unique role, TGF-ß signaling levels induced by sEVs exceed the activity of matching concentrations of soluble ligand TGF-ß. Further, genetic disruption of sEV secretion in highly-metastatic breast cancer cells impairs cancer cell aggressiveness by reducing TGF-ß signaling to nearly-normal levels. Otherwise, TGF-ß signaling activity in non-invasive breast cancer cells is inherently low, but can be amplified by sEVs, enabling invasion and metastasis of poorly-metastatic breast cancer cells. Underscoring the translational potential of inhibiting sEV trafficking in advanced breast cancers, treatment with dimethyl amiloride (DMA) decreases sEV secretion, TGF-ß signaling activity, and breast cancer progression in vivo. Targeting both the sEV trafficking and TGF-ß signaling by combining DMA and SB431542 at suboptimal doses potentiated this effect, normalizing the TGF-ß signaling in primary tumors to potently reduce circulating tumor cells, metastasis, and tumor self-seeding. Collectively, this study establishes sEVs as critical elements in TGF-ß biology, demonstrating the feasibility of inhibiting sEV trafficking as a new therapeutic approach to impair metastasis by normalizing TGF-ß signaling levels in breast cancer cells.

Efficacy of timolol in the treatment of facial hemangioma and its effect on the proliferation and apoptosis of hemangioma stem cells.

To investigate the efficacy of timolol in the treatment of facial hemangioma and the effect on the proliferation and apoptosis of hemangioma stem cells, 60 cases of children with IHs admitted to our hospital between 2020 and 2021 were selected and divided into two groups. The grouping was according to the lottery method, with 30 cases in each group. In the observation group, 0.5% timolol maleate eye drops were applied topically, and in the control group, propranolol hydrochloride tablets were administered orally to observe the efficacy of hemangioma, changes in hemangioma stem cells and the incidence of adverse reactions in both groups. Results showed that combined with the four-level score and ultrasound results, the number of effective treatment cases in the observation group was 28, which was higher than that in the control group, (P<0.05). The total number of adverse reactions in the observation group was 2, with an incidence rate. Under the intervention conditions of timolol, the proliferation level of hemangioma stem cells was inhibited, and the apoptosis rate of hemangioma stem cells increased with the increase of culture time (P<0.05). Among them, the apoptosis rate of the timolol group was higher than that of the blank control group at the same time point (P<0.05), and the difference was most significant at 48h (P<0.001). In conclusion, Timolol can effectively treat facial hemangioma in children, inhibit the proliferation of hemangioma stem cells and promote their apoptosis, with good curative effect, short treatment time and no obvious adverse reactions and it is economical and easy to accept.

An Overview of Adaptive Designs and Some of Their Challenges, Benefits, and Innovative Applications.

Adaptive designs are increasingly developed and used to improve all phases of clinical trials and in biomedical studies in various ways to address different statistical issues. We first present an overview of adaptive designs and note their numerous advantages over traditional clinical trials. In particular, we provide a concrete demonstration that shows how recent adaptive design strategies can further improve an adaptive trial implemented 13 years ago. Despite their usefulness, adaptive designs are still not widely implemented in clinical trials. We offer a few possible reasons and propose some ways to use them more broadly in practice, which include greater availability of software tools and interactive websites to generate optimal adaptive trials freely and effectively, including the use of metaheuristics to facilitate the search for an efficient trial design. To this end, we present several web-based tools for finding various adaptive and nonadaptive optimal designs and discuss nature-inspired metaheuristics. Metaheuristics are assumptions-free general purpose optimization algorithms widely used in computer science and engineering to tackle all kinds of challenging optimization problems, and their use in designing clinical trials is just emerging. We describe a few recent such applications and some of their capabilities for designing various complex trials. Particle swarm optimization is an exemplary nature-inspired algorithm, and similar to others, it has a simple definition but many moving parts, making it hard to study its properties analytically. We investigated one of its hitherto unstudied issues on how to bring back out-of-range candidates during the search for the optimum of the search domain and show that different strategies can impact the success and time of the search. We conclude with a few caveats on the use of metaheuristics for a successful search.

Dynamics of transforming growth factor ß signaling and therapeutic efficacy.

Transforming growth factor ß (TGFß) is a multifunctional cytokine, and its signalling responses are exerted via integrated intracellular pathways and complex regulatory mechanisms. Due to its high potency, TGFß signalling is tightly controlled under normal circumstances, while its dysregulation in cancer favours metastasis. The recognised potential of TGFß as a therapeutic target led to emerging development of anti-TGFß reagents with preclinical success, yet these therapeutics failed to recapitulate their efficacy in experimental settings. In this review, possible reasons for this inconsistency are discussed, addressing the knowledge gap between theoretical and actual behaviours of TGFß signalling. Previous studies on oncogenic cells have demonstrated the spatiotemporal heterogeneity of TGFß signalling intensity. Under feedback mechanisms and exosomal ligand recycling, cancer cells may achieve cyclic TGFß signalling to facilitate dissemination and colonisation. This challenges the current presumption of persistently high TGFß signalling in cancer, pointing to a new direction of research on TGFß-targeted therapeutics.

Totally Intracorporeal Robot-assisted Unilateral or Bilateral Ileal Ureter Replacement for the Treatment of Ureteral Strictures: Technique and Outcomes from a Single Center.

BACKGROUND: Few studies on totally intracorporeal robot-assisted ileal ureter replacement (RA-IUR) have been reported. OBJECTIVE: To report our technique and the outcomes of totally intracorporeal RA-IUR for unilateral or bilateral ureteral reconstruction, involving performing cystoplasty simultaneously. DESIGN, SETTING, AND PARTICIPANTS: Fifteen patients underwent totally intracorporeal RA-IUR from April 2021 to July 2022 at a single center. The perioperative variables were prospectively collected, and the outcomes were assessed. SURGICAL PROCEDURE: The surgical procedure included dissection of the proximal end of the ureteral stricture or renal pelvis, harvesting of the ileal ureter, rebuilding of intestinal continuity, upper anastomosis of the ileum to the renal pelvis or the ureteral end, and lower anastomosis of the ileum to the bladder. All operations were performed intracorporeally. MEASUREMENTS: Patient demographics and perioperative results were prospectively collected and analyzed for perioperative complications and success rates. A descriptive statistical analysis was performed. RESULTS AND LIMITATIONS: All patients successfully underwent totally intracorporeal RA-IUR without open conversion. Seven patients received unilateral RA-IUR and eight received bilateral RA-IUR. The mean (range) length of the harvested ileal segment was 28.3 (15-40) cm, the operative duration was 261.8 (183-381) min, the estimated blood loss was 64.7 (30-100) ml, and the duration of postoperative hospitalization was 10.5 (7-17) d. At a median (range) follow-up of 14 (8-22) mo, the subjective and functional success rates were 100% and 86.7%, respectively. CONCLUSIONS: Our results demonstrate that totally intracorporeal unilateral or bilateral RA-IUR (even with ileocystoplasty) can be performed safely and efficiently with acceptable minor complications and a high success rate. PATIENT SUMMARY: Our study indicates that totally intracorporeal robotic ileal ureter replacement surgery is safe and feasible for ureteral reconstruction, even with ileocystoplasty. The postoperative complications are acceptable. At a median follow-up of 14 (8-22) mo, the subjective and functional success rates were 100% and 86.7%, respectively.

Activin and BMP Signalling in Human Testicular Cancer Cell Lines, and a Role for the Nucleocytoplasmic Transport Protein Importin-5 in Their Crosstalk.

Testicular germ cell tumours (TGCTs) are the most common malignancy in young men. Originating from foetal testicular germ cells that fail to differentiate correctly, TGCTs appear after puberty as germ cell neoplasia in situ cells that transform through unknown mechanisms into distinct seminoma and non-seminoma tumour types. A balance between activin and BMP signalling may influence TGCT emergence and progression, and we investigated this using human cell line models of seminoma (TCam-2) and non-seminoma (NT2/D1). Activin A- and BMP4-regulated transcripts measured at 6 h post-treatment by RNA-sequencing revealed fewer altered transcripts in TCam-2 cells but a greater responsiveness to activin A, while BMP4 altered more transcripts in NT2/D1 cells. Activin significantly elevated transcripts linked to pluripotency, cancer, TGF-ß, Notch, p53, and Hippo signalling in both lines, whereas BMP4 altered TGF-ß, pluripotency, Hippo and Wnt signalling components. Dose-dependent antagonism of BMP4 signalling by activin A in TCam-2 cells demonstrated signalling crosstalk between these two TGF-ß superfamily arms. Levels of the nuclear transport protein, IPO5, implicated in BMP4 and WNT signalling, are highly regulated in the foetal mouse germline. IPO5 knockdown in TCam-2 cells using siRNA blunted BMP4-induced transcript changes, indicating that IPO5 levels could determine TGF-ß signalling pathway outcomes in TGCTs.

N-Terminomic Changes in Neurons During Excitotoxicity Reveal Proteolytic Events Associated With Synaptic Dysfunctions and Potential Targets for Neuroprotection.

Excitotoxicity, a neuronal death process in neurological disorders such as stroke, is initiated by the overstimulation of ionotropic glutamate receptors. Although dysregulation of proteolytic signaling networks is critical for excitotoxicity, the identity of affected proteins and mechanisms by which they induce neuronal cell death remain unclear. To address this, we used quantitative N-terminomics to identify proteins modified by proteolysis in neurons undergoing excitotoxic cell death. We found that most proteolytically processed proteins in excitotoxic neurons are likely substrates of calpains, including key synaptic regulatory proteins such as CRMP2, doublecortin-like kinase I, Src tyrosine kinase and calmodulin-dependent protein kinase IIß (CaMKIIß). Critically, calpain-catalyzed proteolytic processing of these proteins generates stable truncated fragments with altered activities that potentially contribute to neuronal death by perturbing synaptic organization and function. Blocking calpain-mediated proteolysis of one of these proteins, Src, protected against neuronal loss in a rat model of neurotoxicity. Extrapolation of our N-terminomic results led to the discovery that CaMKIIα, an isoform of CaMKIIß, undergoes differential processing in mouse brains under physiological conditions and during ischemic stroke. In summary, by identifying the neuronal proteins undergoing proteolysis during excitotoxicity, our findings offer new insights into excitotoxic neuronal death mechanisms and reveal potential neuroprotective targets for neurological disorders.

Covariate-adjusted response-adaptive designs based on semiparametric approaches.

We consider theoretical and practical issues for innovatively using a large number of covariates in clinical trials to achieve various design objectives without model misspecification. Specifically, we propose a new family of semiparametric covariate-adjusted response-adaptive randomization (CARA) designs and we use the target maximum likelihood estimation (TMLE) to analyze the correlated data from CARA designs. Our approach can flexibly achieve multiple objectives and correctly incorporate the effect of a large number of covariates on the responses without model misspecification. We also obtain the consistency and asymptotic normality of the target parameters, allocation probabilities, and allocation proportions. Numerical studies demonstrate that our approach has advantages over existing approaches, even when the data-generating distribution is complicated.