The Development of Principles for Patient and Public Involvement (PPI) in Preclinical Spinal Cord Research: A Modified Delphi Study.

INTRODUCTION: There is currently limited guidance for researchers on Patient and Public Involvement (PPI) for preclinical spinal cord research, leading to uncertainty about design and implementation. This study aimed to develop evidence-informed principles to support preclinical spinal cord researchers to incorporate PPI into their research. METHODS: This study used a modified Delphi method with the aim of establishing consensus on a set of principles for PPI in spinal cord research. Thirty-eight stakeholders including researchers, clinicians and people living with spinal cord injury took part in the expert panel. Participants were asked to rate their agreement with a series of statements relating to PPI in preclinical spinal cord research over two rounds. As part of Round 2, they were also asked to rate statements as essential or desirable. RESULTS: Thirty-eight statements were included in Round 1, after which five statements were amended and two additional statements were added. After Round 2, consensus (> 75% agreement) was reached for a total of 27 principles, with 13 rated as essential and 14 rated as desirable. The principles with highest agreement related to diversity in representation among PPI contributors, clarity of the purpose of PPI and effective communication. CONCLUSION: This research developed a previously unavailable set of evidence-informed principles to inform PPI in preclinical spinal cord research. These principles provide guidance for researchers seeking to conduct PPI in preclinical spinal cord research and may also inform PPI in other preclinical disciplines. PATIENT AND PUBLIC INVOLVEMENT STATEMENT: This study was conducted as part of a project aiming to develop PPI in preclinical spinal cord injury research associated with an ongoing research collaboration funded by the Irish Rugby Football Union Charitable Trust (IRFU CT) and the Science Foundation Ireland Centre for Advanced Materials and BioEngineering Research (SFI AMBER), with research conducted by the Tissue Engineering Research Group (TERG) at the RCSI University of Medicine and Health Sciences. The project aims to develop an advanced biomaterials platform for spinal cord repair and includes a PPI Advisory Panel comprising researchers, clinicians and seriously injured rugby players to oversee the work of the project. PPI is included in this study through the involvement of members of the PPI Advisory Panel in the conceptualisation of this research, review of findings, identification of key points for discussion and preparation of the study manuscript as co-authors.

Surviving extreme radiation.

Tiny animals known as tardigrades use a combination of DNA repair machinery and a novel protein to mend their genome after intense ionizing radiation.

Resistance to immune checkpoint inhibitors in colorectal cancer with deficient mismatch repair/microsatellite instability: misdiagnosis, pseudoprogression and/or tumor heterogeneity?

Colorectal carcinoma (CRC) with deficiency of the deficient mismatch repair (dMMR) pathway/microsatellite instability (MSI) is characterized by a high mutation load and infiltration of immune cells in the tumor microenvironment. In agreement with these findings, clinical trials have demonstrated a significant activity of immune checkpoint inhibitors (ICIs) in dMMR/MSI metastatic CRC (mCRC) patients and, more recently, in CRC patients with early disease undergoing neoadjuvant therapy. However, despite high response rates and durable clinical benefits, a fraction of mCRC patients, up to 30%, showed progressive disease when treated with single agent anti-programmed cell death 1 (PD-1) antibody. This article discusses the three main causes that have been associated with early progression of dMMR/MSI mCRC patients while on treatment with ICIs, i.e., misdiagnosis, pseudoprogression and tumor heterogeneity. While pseudoprogression probably does not play a relevant role, data from clinical studies demonstrate that some dMMR/MSI CRC cases with rapid progression on ICIs may be misdiagnosed, underlining the importance of correct diagnostics. More importantly, evidence suggests that dMMR/MSI mCRC is a heterogeneous group of tumors with different sensitivity to ICIs. Therefore, we propose novel diagnostic and therapeutic strategies to improve the outcome of dMMR/MSI CRC patients.

Kinase activity of histone chaperone APLF maintains steady state of centrosomes in mouse embryonic stem cells.

Our recent studies revealed the role of mouse Aprataxin PNK-like Factor (APLF) in development. Nevertheless, the comprehensive characterization of mouse APLF remains entirely unexplored. Based on domain deletion studies, here we report that mouse APLF's Acidic Domain and Fork Head Associated (FHA) domain can chaperone histones and repair DNA like the respective human orthologs. Immunofluorescence studies in mouse embryonic stem cells showed APLF co-localized with γ-tubulin within and around the centrosomes and govern the number and integrity of centrosomes via PLK4 phosphorylation. Enzymatic analysis established mouse APLF as a kinase. Docking studies identified three putative ATP binding sites within the FHA domain. Site-directed mutagenesis showed that R37 residue within the FHA domain is indispensable for the kinase activity of APLF thereby regulating the centrosome number. These findings might assist us comprehend APLF in different pathological and developmental conditions and reveal non-canonical kinase activity of proteins harbouring FHA domains that might impact multiple cellular processes.

Menin signaling and therapeutic targeting in breast cancer.

To date, mounting evidence have shown that patients with multiple endocrine neoplasia type 1 (MEN1) may face an increased risk for breast carcinogenesis. The product of the MEN1 gene, menin, was also indicated to be an important regulator in breast cancer signaling network. Menin directly interacts with MLL, EZH2, JunD, NF-κB, PPARγ, VDR, Smad3, ß-catenin and ERα to modulate gene transcriptions leading to cell proliferation inhibition. Moreover, interaction of menin-FANCD2 contributes to the enhancement of BRCA1-mediated DNA repair mechanism. Ectopic expression of menin causes Bax-, Bak- and Caspase-8-dependent apoptosis. However, despite numbers of menin inhibitors were exploited in other cancers, data on the usage of menin inhibitors in breast cancer treatment remain limited. In this review, we focused on the menin associated signaling pathways and gene transcription regulations, with the aim of elucidating its molecular mechanisms and of guiding the development of novel menin targeted drugs in breast cancer therapy.

Interaction of base excision repair gene polymorphism and estrogen-DNA adducts in breast cancer risk among East Asian women.

PURPOSE: In East Asia, the incidence of breast cancer has been increasing rapidly, particularly among premenopausal women. An elevated ratio of estrogen-DNA adducts was linked to a higher risk of breast cancer. The present study explored the influence of the interaction between base excision repair (BER) gene polymorphisms and estrogen-DNA adducts on breast cancer risk. METHODS: We conducted a case-control study comprising healthy volunteers and individuals with benign breast disease (control arm, n = 176) and patients with invasive carcinoma or carcinoma in situ (case arm, n = 177). Genotyping for BER-related genes, including SMUG1, OGG1, ERCC5, and APEX1, was performed. A logistic regression model, incorporating interactions between gene polymorphisms, estrogen-DNA adduct ratio, and clinical variables, was used to identify the risk factors for breast cancer. RESULTS: Univariate analysis indicated marginal associations between breast cancer risk and APEX1 rs1130409 T > G (P = 0.057) and APEX1 rs1760944 T > G (P = 0.065). Multivariate regression analysis revealed significant associations with increased breast cancer risk for APEX1_rs1130409 (GT/GG versus TT) combined with a natural logarithmic value of the estrogen-DNA adduct ratio (estimated OR 1.164, P = 0.023) and premenopausal status with an estrogen-DNA adduct ratio > 2.93 (estimated OR 2.433, P = 0.001). CONCLUSION: APEX1_rs1130409 (GT/GG versus TT) polymorphisms, which are related to decreased BER activity, combined with an increased ratio of estrogen-DNA adducts, increase the risk of breast cancer in East Asian women.

Clinical application of the dissection of the preperitoneal space without electrocoagulation in laparoscopic transperitoneal inguinal hernia repair throughout of the whole process.

Introduction: The dissection of the preperitoneal space is performed using a monopolar instrument to prevent bleeding in laparoscopic transabdominal preperitoneal hernia repair (TAPP). It may also cause energy injuries and nerve damage. Aim: To assess the effectiveness and safety of dissection of the preperitoneal space without electrocoagulation (DPSWE) in TAPP throughout the process. Material and methods: A retrospective analysis of data of 134 patients was made. The electrocoagulation group (EG) relied on monopolar instruments. In the non-electrocoagulation group (NEG) mainly scissors were used without electrocoagulation. The patients were followed for up for 3 months. Intraoperative and postoperative conditions and other complications were observed. Results: The VAS scores in the NEG were lower than those in the EG (p < 0.05). The operation time in the NEG was shorter than that in the EG (p < 0.05). Hospitalization expenses, scrotal seroma formation, and rupture of hernia sac in the NEG were lower than those in the EG (p < 0.05). The intraoperative bleeding volume above 20 ml in the NEG was higher than that in the EG. There was no significant difference in the incidence of postoperative bleeding, vas deferens injury, intestinal injury, surgical site infection, length of hospital stay, urinary retention and hernia recurrence in the NEG and the EG (p > 0.05). There was no significant difference in the incidence of surgical site infections (SSIs) in the NEG and the EG. Conclusions: DPSWE is effective and safe. DPSWE may reduce postoperative pain and have no significant increase in postoperative bleeding.

Three-dimensional sectional measurement approach for serial volume changes in shoulder muscles after arthroscopic rotator cuff repair.

Purpose: This study assessed the serial volume changes in multiple shoulder muscles simultaneously following arthroscopic rotator cuff repair (ARCR) by a three-dimensional (3D) modeling-based sectional measurement. These volume changes were correlated with background preoperative factors. Methods: Four consecutive magnetic resonance imaging scans (preoperatively and postoperatively at 3, 6, and 12 months) of 33 shoulders from 31 patients who underwent arthroscopic rotator cuff repair were examined. We focused on the sectional volume differences of the supraspinatus, infraspinatus, teres minor, and subscapularis between preoperatively and 3 months postoperatively (Dif.pre.3mo) and between 3 and 12 months postoperatively (Dif.3.12mo). The correlation between volume differences and clinical/demographic parameters was determined by a multivariate analysis. Results: No statistically significant differences were observed for most serial changes in the shoulder muscle volumes. The tear-site muscles (supraspinatus and infraspinatus) showed similar tendencies for volume changes, whereas the non-tear-site muscles (teres minor and subscapularis) differed. A negative correlation was observed between Dif.pre.3mo and Dif.3.12mo for the supraspinatus, infraspinatus, and teres minor. These perioperative volume differences might correlate with tear size and symptom duration in the supraspinatus, as well as with a history of steroid injections and work and sports activity levels in the infraspinatus and teres minor. Conclusion: The serial volume changes in multiple shoulder muscles after ARCR measured using our 3D sectional approach exhibited different tendencies and clinical implications depending on the primary and non-primary site of tears. Our method may serve as a potential indicator to facilitate muscle recovery and prevent the progression of postoperative muscle atrophy.

Black phosphorus quantum dot-modified ADSCs as a novel therapeutic for periodontitis bone loss coupling of osteogenesis and osteoimmunomodulation.

Alveolar bone defect repair remains a persistent clinical challenge for periodontitis treatment. The use of peripheral functional seed cells is a hot topic in periodontitis. Herein, we explored the cellular behaviors and osteogenic ability of adipose-derived mesenchymal stem cells (ADSCs) treated with black phosphorus quantum dots (BPQDs). Additionally, macrophage polarization, osteogenic effects and angiogenesis were investigated through the paracrine pathway regulated by BPQD-modified ADSCs. Our results demonstrated that BPQDs showed good biocompatibility with ADSCs and BPQD-modified ADSCs could improve the bone repair in vivo inflammatory microenvironment by regulating osteogenesis and osteoimmunomodulation. The BPQDs increased the osteogenic differentiation of ADSCs via the Wnt/ß-catenin and BMP2/SMAD5/Runx2 signaling pathway. In addition, BPQD-modified ADSCs promoted the osteogenic effect of BMSCs and facilitated the polarization of macrophages from M1 towards M2 phenotype transformation through the paracrine pathway in the periodontitis microenvironment. This strategy provides a novel idea for treatment of alveolar bone defects for periodontitis in the foreseeable future.

Adult-Onset Neuropsychiatric Symptoms as the Presenting Feature of Xeroderma Pigmentosum Group G: A Report of a Rare Case.

Xeroderma pigmentosum is a rare autosomal recessive disorder resulting in heightened cutaneous photosensitivity due to aberrant DNA repair mechanisms. Early-life developmental delay and cognitive impairment have been described in xeroderma pigmentosum cases. However, psychiatric symptoms in adulthood as the presenting feature of xeroderma pigmentosum have not been reported. We report a young adult with xeroderma pigmentosum group G presenting with prominent neuropsychiatric manifestations and evidence of neurodegeneration. The clinical, laboratory, and radiological findings, skin biopsy, and the results of the genetic testing of the patient have been described after obtaining written and informed consent. A young adult male with skin photosensitivity since infancy developed hyper-religiosity, delusions, suicidal ideations, speech hypernasality, lower limb spasticity, and cognitive impairment over the past four years. The MRI of the brain showed diffuse cerebral atrophy. The skin biopsy from bilateral cheeks showed evidence of flattening and thinning of rete ridges, pigment incontinence, and perivascular and periappendageal inflammatory infiltrate. The whole exome sequencing in ethylenediaminetetraacetic acid (EDTA) blood revealed a compound heterozygous likely pathogenic mutation in intron 13 (c.2880-2A>G (3' splice site)) and a mutation in exon 15 (c.3146del (p.Asp1049ValfsTer12)) in the ERCC5 gene suggestive of xeroderma pigmentosum group G. This case highlights that prominent neuropsychiatric features in adulthood can occur due to xeroderma pigmentosum. Thus, xeroderma pigmentosum group G should be considered as a possibility among young adults presenting with neuropsychiatric features, evidence of neurodegeneration, and early-life skin photosensitivity.

Arthroscopic Management of Anterior Shoulder Instability: A Study of Functional Outcome and Analysis.

Background The remarkable range of motion of the shoulder comes at the cost of increased instability, especially anterior instability. Arthroscopic Bankart repair with or without remplissage, which is a minimally invasive surgery, is the preferred treatment for recurrent anterior instability. This study investigated the effectiveness of Bankart repair, with or without remplissage, in restoring function, preventing redislocation, and improving patient satisfaction. Methods A prospective observational study examined 40 patients (19-50 years old) with recurrent anterior instability and MRI-confirmed Bankart or Bankart with Hill-Sachs lesions. Patients underwent arthroscopic Bankart repair with or without remplissage based on the inclusion criteria of this study. Preoperative assessments included demographics, history, physical examination, American Shoulder and Elbow Surgeons (ASES) score, Quick Disabilities of the Arm, Shoulder, and Hand (DASH) score, ROWE score, and plain MRI of the shoulder joint. Post-operative radiographs and rehabilitation were advised. Functional recovery was evaluated at three months and six months after surgery. Results All patients underwent Bankart repair. Among them, 22 with engaging Hill-Sachs lesions received an additional remplissage procedure. Both groups showed significant improvements in their functional scores (p<0.05) and returned to their prior activities. However, the additional remplissage group had a slightly reduced mean external rotation (86.59°) compared with the Bankart repair-only group (90°). Notably, the recurrence rate was very low, with only one patient (2.5%) experiencing instability. Conclusion  Our study emphasizes the importance of proper capsulolabral tissue elevation to achieve a sufficient labral bump during Bankart repair. This technique allowed us to efficiently use only two suture anchors in 35 cases (87.5%). Additionally, remplissage was performed on all identified engaging Hill-Sachs lesions. We found that proper anchor placement and suturing techniques were crucial for successful Bankart repair. The emphasis on the potential cost benefits of a two-anchor approach is a valuable contribution to the field.

Dural Closure Training With Prototyped Model.

INTRODUCTION: The hermetic closure of the dura mater is a critical step in neurosurgical training, often undervalued but crucial to preventing serious complications such as cerebrospinal fluid (CSF) leaks leading to meningitis and death. Inadequate closure, often due to insufficient training, can result in challenging complications, including prolonged hospitalization and reoperation. OBJECTIVE: To address the deficiencies in dural closure training, this study aims to describe a 3D prototype for simulating post-craniotomy dura mater suturing. The objective is to reduce the incidence of CSF leaks and improve the training of neurosurgery residents. DESIGN: The study involves the creation of a 3D prototype based on magnetic resonance imaging and computed tomography scans. The additive manufacturing of structures is performed using ABS filament, and a silicone rubber membrane is used to simulate the meningeal dura mater. Neurosurgery residents undergo training using this model, and the effectiveness is evaluated. SETTING: The study is conducted at the Institute of Neurology of Curitiba (Hospital INC), focusing on neurosurgery residents from the first to fifth year of residency. PARTICIPANTS: Seven residents participate in the study, with varying levels of experience in dural closure procedures. The training involves a simulated surgical environment using the 3D prototype. RESULTS: After training, residents show improvements in confidence and theoretical knowledge related to dural closure. Binary questions indicate a strong desire for more practical training on dural closure, with 85.7% believing in the essential role of 3D molds in their neurosurgery training. CONCLUSION: The study highlights the importance of adequate training for dural closure to prevent serious complications in neurosurgery. The use of 3D simulation models, despite some limitations, proves to be an effective educational strategy. The emerging technology of bioprinting holds promise for further enhancing simulation materials, bringing medical education closer to realistic tissue replication.

Hypoxia-Responsive Prodrug of ATR Inhibitor, AZD6738, Selectively Eradicates Treatment-Resistant Cancer Cells.

Targeted therapy remains the future of anti-cancer drug development, owing to the lack of specificity of current treatments which lead to damage in healthy normal tissues. ATR inhibitors have in recent times demonstrated promising clinical potential, and are currently being evaluated in the clinic. However, despite the considerable optimism for clinical success of these inhibitors, reports of associated normal tissues toxicities remain a concern and can compromise their utility. Here, ICT10336 is reported, a newly developed hypoxia-responsive prodrug of ATR inhibitor, AZD6738, which is hypoxia-activated and specifically releases AZD6738 only in hypoxic conditions, in vitro. This hypoxia-selective release of AZD6738 inhibited ATR activation (T1989 and S428 phosphorylation) and subsequently abrogated HIF1a-mediated adaptation of hypoxic cancers cells, thus selectively inducing cell death in 2D and 3D cancer models. Importantly, in normal tissues, ICT10336 is demonstrated to be metabolically stable and less toxic to normal cells than its active parent agent, AZD6738. In addition, ICT10336 exhibited a superior and efficient multicellular penetration ability in 3D tumor models, and selectively eradicated cells at the hypoxic core compared to AZD6738. In summary, the preclinical data demonstrate a new strategy of tumor-targeted delivery of ATR inhibitors with significant potential of enhancing the therapeutic index.

Detection of Endoleak after Endovascular Aortic Repair through Deep Learning Based on Non-contrast CT.

OBJECTIVES: To develop and validate a deep learning model for detecting post-endovascular aortic repair (EVAR) endoleak from non-contrast CT. METHODS: This retrospective study involved 245 patients who underwent EVAR between September 2016 and December 2022. All patients underwent both non-enhanced and enhanced follow-up CT. The presence of endoleak was evaluated based on computed tomography angiography (CTA) and radiology reports. First, the aneurysm sac was segmented, and radiomic features were extracted on non-contrast CT. Statistical analysis was conducted to investigate differences in shape and density characteristics between aneurysm sacs with and without endoleak. Subsequently, a deep learning model was trained to generate predicted segmentation of the endoleak. A binary decision was made based on whether the model produced a segmentation to detect the presence of endoleak. The absence of a predicted segmentation indicated no endoleak, while the presence of a predicted segmentation indicated endoleak. Finally, the performance of the model was evaluated by comparing the predicted segmentation with the reference segmentation obtained from CTA. Model performance was assessed using metrics such as dice similarity coefficient, sensitivity, specificity, and the area under the curve (AUC). RESULTS: This study finally included 85 patients with endoleak and 82 patients without endoleak. Compared to patients without endoleak, patients with endoleak had higher CT values and greater dispersion. The AUC in validation group was 0.951, dice similarity coefficient was 0.814, sensitivity was 0.877, and specificity was 0.884. CONCLUSION: This deep learning model based on non-contrast CT can detect endoleak after EVAR with high sensitivity.

Composite Hydrogel Sealants for Annulus Fibrosus Repair.

Intervertebral disc (IVD) herniation is a leading cause of disability and lower back pain, causing enormous socioeconomic burdens. The standard of care for disc herniation is nucleotomy, which alleviates pain but does not repair the annulus fibrosus (AF) defect nor recover the biomechanical function of the disc. Existing bioadhesives for AF repair are limited by insufficient adhesion and significant mechanical and geometrical mismatch with the AF tissue, resulting in the recurrence of protrusion or detachment of bioadhesives. Here, we report a composite hydrogel sealant constructed from a composite of a three-dimensional (3D)-printed thermoplastic polyurethane (TPU) mesh and tough hydrogel. We tailored the fiber angle and volume fraction of the TPU mesh design to match the angle-ply structure and mechanical properties of native AF. Also, we proposed and tested three types of geometrical design of the composite hydrogel sealant to match the defect shape and size. Our results show that the sealant could mimic native AF in terms of the elastic modulus, flexural modulus, and fracture toughness and form strong adhesion with the human AF tissue. The bovine IVD tests show the effectiveness of the composite hydrogel sealant for AF repair and biomechanics recovery and for preventing herniation with its heightened stiffness and superior adhesion. By harnessing the combined capabilities of 3D printing and bioadhesives, these composite hydrogel sealants demonstrate promising potential for diverse applications in tissue repair and regeneration.

DNA Tetrahedron Delivering miR-21-5p Promotes Senescent Bone Defects Repair through Synergistic Regulation of Osteogenesis and Angiogenesis.

Compromised osteogenesis and angiogenesis is the character of stem cell senescence, which brought difficulties for bone defects repairing in senescent microenvironment. As the most abundant bone-related miRNA, miRNA-21-5p plays a crucial role in inducing osteogenic and angiogenic differentiation. However, highly efficient miR-21-5p delivery still confronts challenges including poor cellular uptake and easy degradation. Herein, TDN-miR-21-5p nanocomplex is constructed based on DNA tetrahedral (TDN) and has great potential in promoting osteogenesis and alleviating senescence of senescent bone marrow stem cells (O-BMSCs), simultaneously enhancing angiogenic capacity of senescent endothelial progenitor cells (O-EPCs). Of note, the activation of AKT and Erk signaling pathway may direct regulatory mechanism of TDN-miR-21-5p mediated osteogenesis and senescence of O-BMSCs. Also, TDN-miR-21-5p can indirectly mediate osteogenesis and senescence of O-BMSCs through pro-angiogenic growth factors secreted from O-EPCs. In addition, gelatin methacryloyl (GelMA) hydrogels are mixed with TDN and TDN-miR-21-5p to fabricate delivery scaffolds. TDN-miR-21-5p@GelMA scaffold exhibits greater bone repair with increased expression of osteogenic- and angiogenic-related markers in senescent critical-size cranial defects in vivo. Collectively, TDN-miR-21-5p can alleviate senescence and induce osteogenesis and angiogenesis in senescent microenvironment, which provides a novel candidate strategy for senescent bone repair and widen clinical application of TDNs-based gene therapy.

Strain variation in the Candida albicans iron limitation response.

Iron acquisition is critical for pathogens to proliferate during invasive infection, and the human fungal pathogen Candida albicans is no exception. The iron regulatory network, established in reference strain SC5314 and derivatives, includes the central player Sef1, a transcription factor that activates iron acquisition genes in response to iron limitation. Here, we explored potential variation in this network among five diverse C. albicans strains through mutant analysis, Nanostring gene expression profiling, and, for two strains, RNA-Seq. Our findings highlight four features that may inform future studies of natural variation and iron acquisition in this species. (i) Conformity: In all strains, major iron acquisition genes are upregulated during iron limitation, and a sef1Δ/Δ mutation impairs that response and growth during iron limitation. (ii) Response variation: Some aspects of the iron limitation response vary among strains, notably the activation of hypha-associated genes. As this gene set is tied to tissue damage and virulence, variation may impact the progression of infection. (iii) Genotype-phenotype variation: The impact of a sef1Δ/Δ mutation on cell wall integrity varies, and for the two strains examined the phenotype correlated with sef1Δ/Δ impact on several cell wall integrity genes. (iv) Phenotype discovery: DNA repair genes were induced modestly by iron limitation in sef1Δ/Δ mutants, with fold changes we would usually ignore. However, the response occurred in both strains tested and was reminiscent of a much stronger response described in Cryptococcus neoformans, a suggestion that it may have biological meaning. In fact, we observed that the iron limitation of a sef1Δ/Δ mutant caused recessive phenotypes to emerge at two heterozygous loci. Overall, our results show that a network that is critical for pathogen proliferation presents variation outside of its core functions.IMPORTANCEA key virulence factor of Candida albicans is the ability to maintain iron homeostasis in the host where iron is scarce. We focused on a central iron regulator, SEF1. We found that iron regulator Sef1 is required for growth, cell wall integrity, and genome integrity during iron limitation. The novel aspect of this work is the characterization of strain variation in a circuit that is required for survival in the host and the connection of iron acquisition to genome integrity in C. albicans.

Arabidopsis DNA glycosylase MBD4L improves recovery of aged seeds.

DNA glycosylases initiate the base excision repair (BER) pathway by catalyzing the removal of damaged or mismatched bases from DNA. The Arabidopsis DNA glycosylase methyl-CpG-binding domain protein 4 like (MBD4L) is a nuclear enzyme triggering BER in response to the genotoxic agents 5-fluorouracil and 5-bromouracil. To date, the involvement of MBD4L in plant physiological processes has not been analyzed. To address this, we studied the enzyme functions in seeds. We found that imbibition induced the MBD4L gene expression by generating two alternative transcripts, MBD4L.3 and MBD4L.4. Gene activation was stronger in aged than in non-aged seeds. Seeds from mbd4l-1 mutants displayed germination failures when maintained under control or ageing conditions, while 35S:MBD4L.3/mbd4l-1 and 35S:MBD4L.4/mbd4l-1 seeds reversed these phenotypes. Seed nuclear DNA repair, assessed by comet assays, was exacerbated in an MBD4L-dependent manner at 24 h post-imbibition. Under this condition, the BER genes ARP, APE1L, and LIG1 showed higher expression in 35S:MBD4L.3/mbd4l-1 and 35S:MBD4L.4/mbd4l-1 than in mbd4l-1 seeds, suggesting that these components could coordinate with MBD4L to repair damaged DNA bases in seeds. Interestingly, the ATM, ATR, BRCA1, RAD51, and WEE1 genes associated with the DNA damage response (DDR) pathway were activated in mbd4l-1, but not in 35S:MBD4L.3/mbd4l-1 or 35S:MBD4L.4/mbd4l-1 seeds. These results indicate that MBD4L is a key enzyme of a BER cascade that operates during seed imbibition, whose deficiency would cause genomic damage detected by DDR, generating a delay or reduction in germination.

Mitral Valve Repair with Leaflet Resection versus Preservation for Degenerative Posterior Leaflet Prolapse.

OBJECTIVES: The optimal technique for repairing posterior mitral valve (MV) leaflet (PMVL) prolapse remains undetermined. We aimed to compare leaflet resection and neo-chordae implantation in patients undergoing MV repair for posterior leaflet prolapse, focusing on trans-mitral pressure gradient (PG) and recurrence of mitral regurgitation (MR). METHODS: We enrolled patients undergoing MV repair using either leaflet resection or neo-chordae implantation for single-segment prolapse of PMVL between 2000 and 2021 at our institution. Longitudinal outcomes were evaluated after adjustments with inverse-probability-of-treatment weighting (IPTW). Repeat echocardiographic measurements (n=3,473, 5.4/patient) of trans-mitral PG and significant (moderate or severe) MR recurrence were estimated using nonlinear mixed-effect models. Subgroup analyses were conducted based on the size and type of prosthesis. RESULTS: Among 639 patients, leaflet resection was used in 479 (75.0%) and neo-chordae implantation in 160 (25.0%). In the IPTW-adjusted cohort, the risk of death (P=0.623) and MV reoperation (P=0.340) did not significantly differ between the two groups during a median follow-up of 97.3 months. Echocardiographic data showed comparable mean (at 5 years, 3.8 vs. 4.0 mmHg; P=0.442) and peak (9.6 vs. 10.4mmHg; P=0.131) PGs between groups, which persisted in most subgroup analyses. However, neo-chordae implantation was associated with a higher probability of significant MR recurrence compared to leaflet resection (at 5 years, 16.1% vs. 7.0%; P<0.001). CONCLUSIONS: Leaflet resection yielded similar clinical outcomes and trans-mitral PGs compared to neo-chordae implantation after MV repair, with a lower MR recurrence rate. These findings underscore the need to reassess the efficacy of neo-chordae implantation relative to leaflet resection.