Cost-Effectiveness Analysis of Regorafenib versus Other Third-Line Treatments for Metastatic Colorectal Cancer.

Background: Regorafenib, a novel multikinase inhibitor, has been approved by the US Food and Drug Administration as a standard treatment choice for metastatic colorectal cancer (mCRC). Nonetheless, its substantial cost places a significant burden on social health resources and patients. However, the cost-effectiveness (CE) of regorafenib compared to other third-line therapies is still undetermined. Objective: This study aims to assess the CE of regorafenib compared to other third-line therapies for the treatment of mCRC. Methods: We conducted a comprehensive literature search in PubMed, Medline, Scopus, Embase, Cochrane Library, as well as nine other databases to identify relevant studies published up to October 2023, focusing on patients with mCRC and examining the cost-effectiveness of regorafenib. Following the screening and extraction of pertinent data, the study quality was assessed using the Quality of Health Economic Studies (QHES) checklist. Results: The literature search yielded 751 records, and after applying the inclusion criteria, 13 studies from 7 different countries were included. Of these, 7 studies evaluated the cost-effectiveness of regorafenib compared to trifluridine/tipiracil (TAS-102), 3 studies compared regorafenib with best supportive care (BSC), and 3 studies compared regorafenib with fruquintinib, serplulimab, and regorafenib dose optimization (ReDo).The quality of the included studies was high with an average QHES scores of 85.62. Regorafenib standard dose proves to be less cost-effective than alternative third-line therapies. Implementing a dose optimization strategy could potentially rectify this disparity and enhance the cost-effectiveness of regorafenib. Conclusion: The use of the standard dose of regorafenib is generally regarded as not cost-effective when compared to other third-line therapies for patients with mCRC. However, implementing a dose-escalation strategy may enhance regorafenib's cost-effectiveness. Consequently, significant price reductions or optimizing the dose of regorafenib are required to achieve cost-effectiveness.

Structural insights into the cross-exon to cross-intron spliceosome switch.

Early spliceosome assembly can occur through an intron-defined pathway, whereby U1 and U2 small nuclear ribonucleoprotein particles (snRNPs) assemble across the intron1. Alternatively, it can occur through an exon-defined pathway2-5, whereby U2 binds the branch site located upstream of the defined exon and U1 snRNP interacts with the 5' splice site located directly downstream of it. The U4/U6.U5 tri-snRNP subsequently binds to produce a cross-intron (CI) or cross-exon (CE) pre-B complex, which is then converted to the spliceosomal B complex6,7. Exon definition promotes the splicing of upstream introns2,8,9 and plays a key part in alternative splicing regulation10-16. However, the three-dimensional structure of exon-defined spliceosomal complexes and the molecular mechanism of the conversion from a CE-organized to a CI-organized spliceosome, a pre-requisite for splicing catalysis, remain poorly understood. Here cryo-electron microscopy analyses of human CE pre-B complex and B-like complexes reveal extensive structural similarities with their CI counterparts. The results indicate that the CE and CI spliceosome assembly pathways converge already at the pre-B stage. Add-back experiments using purified CE pre-B complexes, coupled with cryo-electron microscopy, elucidate the order of the extensive remodelling events that accompany the formation of B complexes and B-like complexes. The molecular triggers and roles of B-specific proteins in these rearrangements are also identified. We show that CE pre-B complexes can productively bind in trans to a U1 snRNP-bound 5' splice site. Together, our studies provide new mechanistic insights into the CE to CI switch during spliceosome assembly and its effect on pre-mRNA splice site pairing at this stage.

A New Species of Diploderma (Squamata, Agamidae) from the Valley of Dadu River in Sichuan Province, with a Redescription of Topotypes of D. splendidum from Hubei Province, China.

This study describes a novel species of Diploderma (Squamata, Agamidae) from the lower valley of the Dadu River of the Sichuan Province of Western China based on its distinct morphological features and molecular evidence. D. daduense sp. nov. can be distinguished from its congeners by its tympanum concealed; head mainly green-yellow, supplemented by black; skin folds under the nuchal and dorsal crest obviously present in adult males only, its vertebral crest discontinuous between nuchal and dorsal sections with a distinct gap; transverse gular fold present but not obvious in some individuals; gular spot absent in both sexes; dorsolateral stripes green-yellow anteriorly, cyan in the center and blurry off-white posteriorly in adult males, the upper edge of dorsolateral stripes strongly jagged in adult males; no radial stripes around the eyes; inner-lip coloration smoky-white, and the coloration of the tongue and oral cavity as a light-flesh color in life; bright green-yellow transverse stripes on dorsal body in males; black patches are evenly distributed along the vertebral line between the dorsolateral stripes from the neck to the base of the tail in males; beech-brown or gray-brown line along the vertebral line with heart-shaped or diamond-shaped black patches on the dorsal body in females; and supratemporals fewer than four on at least one side. The phylogenetic tree based on mitochondrial ND2 sequences indicates that D. daduense sp. nov. forms an independent clade with strong support 1/100 in ML bootstrap/Bayesian posterior probability and is the sister group to D. splendidum. At the inter-species level, the p-distance is at least 6.95%, further confirming that an independent species had been identified. Our work raises the number of species within the genus Diploderma to 47.

Probing Nonadiabaticity of Proton-Coupled Electron Transfer in Ribonucleotide Reductase.

The enzyme ribonucleotide reductase, which is essential for DNA synthesis, initiates the conversion of ribonucleotides to deoxyribonucleotides via radical transfer over a 32 Å pathway composed of proton-coupled electron transfer (PCET) reactions. Previously, the first three PCET reactions in the α subunit were investigated with hybrid quantum mechanical/molecular mechanical (QM/MM) free energy simulations. Herein, the fourth PCET reaction in this subunit between C439 and guanosine diphosphate (GDP) is simulated and found to be slightly exoergic with a relatively high free energy barrier. To further elucidate the mechanisms of all four PCET reactions, we analyzed the vibronic and electron-proton nonadiabaticities. This analysis suggests that interfacial PCET between Y356 and Y731 is vibronically and electronically nonadiabatic, whereas PCET between Y731 and Y730 and between C439 and GDP is fully adiabatic and PCET between Y730 and C439 is in the intermediate regime. These insights provide guidance for selecting suitable rate constant expressions for these PCET reactions.

Sustained Improvement of Appropriateness in Surgical Antimicrobial Prophylaxis with the Application of Quality Control Circle.

Purpose: Quality control circle (QCC) has acquired success in many fields in healthcare industry as a process management tool, whereas its efficacy in surgical antimicrobial prophylaxis (SAP) remains unknown. This study aimed to implement QCC interventions to improve the appropriateness of SAP. Methods: A QCC activity team was established to grasp the current situation of SAP in clean surgery procedure, set target, formulate corresponding countermeasures and implement and review them in stages. The plan-do-check-act (PDCA) method was cyclically applied. Results: The appropriateness of antibiotic prophylaxis before (January to December 2020) and after (January to December 2021) the implementation of QCC activities were evaluated based on relevant international and Chinese SAP guidelines. The overall SAP appropriateness was significantly improved from 68.72% before QCC to 93.7% post QCC implementation (P<0.01). A significant improvement (P<0.05) was also determined for each category: selection (from 78.82% to 96.06%), duration (from 90.15% to 96.46%), indication (from 94.09% to 97.64%), timing of first dose (from 96.55% to 99.21%), antimicrobial usage (from 96.8% to 99.41%), re-dosing of antimicrobial (from 96.55% to 99.21%). Conclusion: Implementation of a QCC program can optimize the use of antibiotics and improve the appropriateness of SAP and is of practical importance to their standardization.

Direct Proton-Coupled Electron Transfer between Interfacial Tyrosines in Ribonucleotide Reductase.

Ribonucleotide reductase (RNR) regulates DNA synthesis and repair in all organisms. The mechanism of Escherichia coli RNR requires radical transfer over a proton-coupled electron transfer (PCET) pathway spanning ∼32 Å across two protein subunits. A key step along this pathway is the interfacial PCET reaction between Y356 in the ß subunit and Y731 in the α subunit. Herein, this PCET reaction between two tyrosines across an aqueous interface is explored with classical molecular dynamics and quantum mechanical/molecular mechanical (QM/MM) free energy simulations. The simulations suggest that the water-mediated mechanism involving double proton transfer through an intervening water molecule is thermodynamically and kinetically unfavorable. The direct PCET mechanism between Y356 and Y731 becomes feasible when Y731 is flipped toward the interface and is predicted to be approximately isoergic with a relatively low free energy barrier. This direct mechanism is facilitated by the hydrogen bonding of water to both Y356 and Y731. These simulations provide fundamental insights into radical transfer across aqueous interfaces.

Structural basis of the bHLH domains of MyoD-E47 heterodimer.

The basic helix-loop-helix (bHLH) family is one of the most conserved transcription factor families that plays an important role in regulating cell growth, differentiation and tissue development. Typically, members of this family form homo- or heterodimers to recognize specific motifs and activate transcription. MyoD is a vital transcription factor that regulates muscle cell differentiation. However, it is necessary for MyoD to form a heterodimer with E-proteins to activate transcription. Even though the crystal structure of the MyoD homodimer has been determined, the structure of the MyoD heterodimer in complex with the E-box protein remains unclear. In this study, we determined the crystal structure of the bHLH domain of the MyoD-E47 heterodimer at 2.05 Å. Our structural analysis revealed that MyoD interacts with E47 through a hydrophobic interface. Moreover, we confirmed that heterodimerization could enhance the binding affinity of MyoD to E-box sequences. Our results provide new structural insights into the heterodimer of MyoD and E-box protein, suggesting the molecular mechanism of transcription activation of MyoD upon binding to E-box protein.

Role of Water in Proton-Coupled Electron Transfer between Tyrosine and Cysteine in Ribonucleotide Reductase.

Ribonucleotide reductase (RNR) catalyzes the reduction of ribonucleotides to deoxyribonucleotides and is critical for DNA synthesis and repair in all organisms. Its mechanism requires radical transfer along a ∼32 Špathway through a series of proton-coupled electron transfer (PCET) steps. Previous simulations suggested that a glutamate residue (E623) mediates the PCET reaction between two stacked tyrosine residues (Y730 and Y731) through a proton relay mechanism. This work focuses on the adjacent PCET reaction between Y730 and a cysteine residue (C439). Quantum mechanical/molecular mechanical free energy simulations illustrate that when Y730 and Y731 are stacked, E623 stabilizes the radical on C439 through hydrogen bonding with the Y730 hydroxyl group. When Y731 is flipped away from Y730, a water molecule stabilizes the radical on C439 through hydrogen bonding with Y730 and lowers the free energy barrier for radical transfer from Y730 to C439 through electrostatic interactions with the transferring hydrogen but does not directly accept the proton. These simulations indicate that the conformational motions and electrostatic interactions of the tyrosines, cysteine, glutamate, and water strongly impact the thermodynamics and kinetics of these two coupled PCET reactions. Such insights are important for protein engineering efforts aimed at altering radical transfer in RNR.

Secondary hand infection with Eikenella corrodens and Staphylococcus aureus in a patient with Behcet's disease: a case report.

We report the first case of a woman with Behcet's disease (BD) with multiple hand ulcers secondary to coninfection by Eikenella corrodens and Staphylococcus aureus resulting in necrotizing fasciitis. She had a long history of BD including long courses of prednisone and immunosuppressants. The patient was hospitalized for multiple superficial ulcers, swelling, and infection of the hands. After admission, pus culture examination revealed rare coinfection by E. corrodens and S. aureus. We administered moxifloxacin and vancomycin to control infection and methylprednisolone to control BD. We performed incision, drainage, and debridement of the ulcer surface on the hands to reduce the pus on the wound surface. E. corrodens infections occur in immunosuppressed patients and contribute to coinfections, particularly in patients with BD in whom destruction of the skin immune barrier increases risk to secondary infections. For severe and complicated hand infections, efforts should be made to identify pathogenic microorganisms so appropriate antibiotics and other interventions can be given to control the infection.

MyoD is a 3D genome structure organizer for muscle cell identity.

The genome exists as an organized, three-dimensional (3D) dynamic architecture, and each cell type has a unique 3D genome organization that determines its cell identity. An unresolved question is how cell type-specific 3D genome structures are established during development. Here, we analyzed 3D genome structures in muscle cells from mice lacking the muscle lineage transcription factor (TF), MyoD, versus wild-type mice. We show that MyoD functions as a "genome organizer" that specifies 3D genome architecture unique to muscle cell development, and that H3K27ac is insufficient for the establishment of MyoD-induced chromatin loops in muscle cells. Moreover, we present evidence that other cell lineage-specific TFs might also exert functional roles in orchestrating lineage-specific 3D genome organization during development.

Factors relating to bone mineral density in young and middle-aged patients with ankylosing spondylitis.

BACKGROUND: Ankylosing spondylitis (AS) is a common chronic progressive rheumatic disease. The aim of this study was to explore factors influencing abnormal bone mineral density (BMD) in young and middle-aged patients with AS. METHODS: From July 2014 to August 2018, hospitalized patients with AS and health examinees in the health examination center of our clinics, ranging in age from 20 to 50 years, were monitored. The BMD of the lumbar spine and femoral neck of AS patients and those of a healthy control group were measured using dual-energy X-ray absorption. The BMDs of AS patients were compared with respect to age, course of disease, iritis, smoking habits, sex, height, weight, body mass index (BMI), medication use, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), platelet volume, platelet count, uric acid (UA), alkaline phosphatase (AKP), and calcium ion levels. Single-nucleotide polymorphisms (SNPs) related to BMD were screened using genome-wide association analysis. RESULTS: There was no statistical difference in the proportion of abnormal bone masses between the different body parts. The BMD of all bones in AS patients was lower than that in healthy controls (P < 0.05). Additionally, BMD was correlated with serum calcium and CRP in AS patients (P < 0.05), but not with age, platelet volume, platelet count, ESR, UA, AKP, height, weight, and BMI. The incidence of abnormal bone mass in AS patients was correlated with sex (P < 0.05), but not with medication use, iritis, or smoking. BMD of the lumbar spine in AS patients did not correlate linearly with the course of the disease, but BMD of the femoral neck correlated linearly with the course of the disease (P < 0.05). BMD was correlated with multiple SNPs in patients with AS. Lumbar BMD was correlated with rs7025373 and rs7848078. Femoral head BMD was correlated with 3:102157365, 3:102157417, rs1252202, rs1681355, rs3891857, rs7842614, and rs9870734, suggesting that genetic factors play a role in BMD in patients with AS. CONCLUSIONS: The proportion of abnormal bone mass in AS patients was higher than that in healthy individuals of the same age. The factors related to BMD in patients with AS are gender, CRP, and blood calcium. The BMD of the femoral neck of AS patients decreases with the course of the disease, but BMD of the lumbar spine is not related to the course of the disease. BMD in AS patients is associated with multiple SNPs.

Glutamate Mediates Proton-Coupled Electron Transfer Between Tyrosines 730 and 731 in Escherichia coli Ribonucleotide Reductase.

Ribonucleotide reductase (RNR) is an essential enzyme in DNA synthesis for all living organisms. It reduces ribonucleotides to the corresponding deoxyribonucleotides by a reversible radical transfer mechanism. The active form of E. coli Ia RNR is composed of two subunits, α and ß, which form an active asymmetric α2ß2 complex. The radical transfer pathway involves a series of proton-coupled electron transfer (PCET) reactions spanning α and ß over ∼32 Å. Herein, quantum mechanical/molecular mechanical free energy simulations of PCET between tyrosine residues Y730 and Y731 are performed on the recently solved cryo-EM structure of the active α2ß2 complex, which includes a pre-turnover α/ß pair with an ordered PCET pathway and a post-turnover α'/ß' pair. The free energy surfaces in both the pre- and post-turnover states are computed. According to the simulations, forward radical transfer from Y731 to Y730 is thermodynamically favored in the pre-turnover state, and backward radical transfer is favored in the post-turnover state, consistent with the reversible mechanism. E623, a glutamate residue that is near these tyrosines only in the pre-turnover state, is discovered to play a key role in facilitating forward radical transfer by thermodynamically stabilizing the radical on Y730 through hydrogen-bonding and electrostatic interactions and lowering the free energy barrier via a proton relay mechanism. Introduction of fluorinated Y731 exhibits expected thermodynamic trends without altering the basic mechanism. These simulations suggest that E623 influences the directionality of PCET between Y731 and Y730 and predict that mutation of E623 will impact catalysis.

The Long Noncoding RNA Landscape of the Mouse Eye.

Purpose: Long noncoding RNAs (lncRNAs) are important regulators of diverse biological functions. However, an extensive in-depth analysis of their expression profile and function in mammalian eyes is still lacking. Here we describe comprehensive landscapes of stage-dependent and tissue-specific lncRNA expression in the mouse eye. Methods: Affymetrix transcriptome array profiled lncRNA signatures from six different ocular tissue subsets (i.e., cornea, lens, retina, RPE, choroid, and sclera) in newborn and 8-week-old mice. Quantitative RT-PCR analysis validated array findings. Cis analyses and Gene Ontology (GO) annotation of protein-coding genes adjacent to signature lncRNA loci clarified potential lncRNA roles in maintaining tissue identity and regulating eye maturation during the aforementioned phase. Results: In newborn and 8-week-old mice, we identified 47,332 protein-coding and noncoding gene transcripts. LncRNAs comprise 19,313 of these transcripts annotated in public data banks. During this maturation phase of these six different tissue subsets, more than 1000 lncRNAs expression levels underwent ≥2-fold changes. qRT-PCR analysis confirmed part of the gene microarray analysis results. K-means clustering identified 910 lncRNAs in the P0 groups and 686 lncRNAs in the postnatal 8-week-old groups, suggesting distinct tissue-specific lncRNA clusters. GO analysis of protein-coding genes proximal to lncRNA signatures resolved close correlations with their tissue-specific functional maturation between P0 and 8 weeks of age in the 6 tissue subsets. Conclusions: Characterizating maturational changes in lncRNA expression patterns as well as tissue-specific lncRNA signatures in six ocular tissues suggest important contributions made by lncRNA to the control of developmental processes in the mouse eye.

Differential effects on ARF stability by normal versus oncogenic levels of c-Myc expression.

ARF suppresses aberrant cell growth upon c-Myc overexpression by activating p53 responses. Nevertheless, the precise mechanism by which ARF specifically restrains the oncogenic potential of c-Myc without affecting its normal physiological function is not well understood. Here, we show that low levels of c-Myc expression stimulate cell proliferation, whereas high levels inhibit by activating the ARF/p53 response. Although the mRNA levels of ARF are induced in both scenarios, the accumulation of ARF protein occurs only when ULF-mediated degradation of ARF is inhibited by c-Myc overexpression. Moreover, the levels of ARF are reduced through ULF-mediated ubiquitination upon DNA damage. Blocking ARF degradation by c-Myc overexpression dramatically stimulates the apoptotic responses. Our study reveals that ARF stability control is crucial for differentiating normal (low) versus oncogenic (high) levels of c-Myc expression and suggests that differential effects on ULF- mediated ARF ubiquitination by c-Myc levels act as a barrier in oncogene-induced stress responses.

RFP-mediated ubiquitination of PTEN modulates its effect on AKT activation.

The PTEN tumor suppressor is a lipid phosphatase that has a central role in regulating the phosphatidylinositol-3-kinase (PI3K) signal transduction cascade. Nevertheless, the mechanism by which the PTEN activity is regulated in cells needs further elucidation. Although previous studies have shown that ubiquitination of PTEN can modulate its stability and subcellular localization, the role of ubiquitination in the most critical aspect of PTEN function, its phosphatase activity, has not been fully addressed. Here, we identify a novel E3 ubiquitin ligase of PTEN, Ret finger protein (RFP), that is able to promote atypical polyubiquitinations of PTEN. These ubiquitinations do not lead to PTEN instability or relocalization, but rather significantly inhibit PTEN phosphatase activity and therefore modulate its ability to regulate the PI3K signal transduction cascade. Indeed, RFP overexpression relieves PTEN-mediated inhibitory effects on AKT activation; in contrast, RNAi-mediated knockdown of endogenous RFP enhances the ability of PTEN to suppress AKT activation. Moreover, RFP-mediated ubiquitination of PTEN inhibits PTEN-dependent activation of TRAIL expression and also suppresses its ability to induce apoptosis. Our findings demonstrate a crucial role of RFP-mediated ubiquitination in controlling PTEN activity.

Inactivation of arf-bp1 induces p53 activation and diabetic phenotypes in mice.

It is well accepted that the Mdm2 ubiquitin ligase acts as a major factor in controlling p53 stability and activity in vivo. Although several E3 ligases have been reported to be involved in Mdm2-independent p53 degradation, the roles of these ligases in p53 regulation in vivo remain largely unknown. To elucidate the physiological role of the ubiquitin ligase ARF-BP1, we generated arf-bp1 mutant mice. We found that inactivation of arf-bp1 during embryonic development in mice resulted in p53 activation and embryonic lethality, but the mice with arf-bp1 deletion specifically in the pancreatic ß-cells (arf-bp1(FL/Y)/RIP-cre) were viable and displayed no obvious abnormality after birth. Interestingly, these mice showed dramatic loss of ß-cells as mice aged, and >50% of these mice died of severe diabetic symptoms before reaching 1 year of age. Notably, the diabetic phenotype of these mice was largely reversed by concomitant deletion of p53, and the life span of the mice was significantly extended (p53(LFL/FL)/arf-bp1(FL/Y)/RIP-cre). These findings underscore an important role of ARF-BP1 in maintaining ß-cell homeostasis in aging mice and reveal that the stability of p53 is critically regulated by ARF-BP1 in vivo.