Repair System Research Articles

Reconstitution of the Early Stage of Chetomin Biosynthesis in Aspergillus fumigatus Leads to the Production of Epipolythiodioxopiperazines.

Using CRISPR-Cas9 technology and a microhomology-mediated end-joining repair system, we substituted genes of the gliotoxin pathway in Aspergillus fumigatus with genes responsible for chetomin biosynthesis from Chaetomium cochliodes, leading to the production of three new epipolythiodioxopiperazines (ETPs). This work represents the first successful endeavor to produce ETPs in a non-native host. Additionally, the simultaneous disruption of five genes in a single transformation marks the most extensive gene knockout event in filamentous fungi to date.

Prime Editing and DNA Repair System: Balancing Efficiency with Safety

Prime Editing and DNA Repair System: Balancing Efficiency with Safety

Implementation of the Versius Surgical System in Complex Abdominal Wall Repair: First Reported Case of an Robotic ETEP/TAR Procedure.

Robotic ventral hernia repair has been increasing globally, with comparable outcomes to laparoscopic repair and lower rates of conversion to open surgery. Robotic surgery is increasing in popularity, and there is a number of new robotic systems entering the marketing. We report the first case of a Roboic eTEP using the Versius robotic system in a patient with an incisional hernia. Surgery was performed using the Versius system from CMR surgical which consists of bedside units for each instrument and a console. The patient presented with an incisional hernia measuring 9.5×5cm in the left flank. The patient was discharged on postoperative day (POD) 2 with a drain. There was no need for opioids. The drain was removed at POD 7. The patient presented at POD 10 with erythema and cellulitis in the area that previously had tape on it, and it was resolved with a short course of oral antibiotics. The eTEP technique for hernia surgery was safe and feasible using the Versius robotic system. Implementation is possible in experienced hands with minimal changes to the surgical techniques.

Pleiotropic effects of nitric oxide sustained-release system for peripheral nerve repair.

The regenerative microenvironment after peripheral nerve injury is imbalanced and difficult to rebalance, which is mainly affected by inflammation, oxidative stress, and inadequate blood supply. The difficulty in remodeling the nerve regeneration microenvironment is the main reason for slow nerve regeneration. Traditional drug treatments have certain limitations, such as difficulty in penetrating the blood-nerve barrier and lack of pleiotropic effects. Therefore, there is an urgent need to build multifunctional nerve grafts that can effectively regulate the regenerative microenvironment and promote nerve regeneration. Nitric oxide (NO), a highly effective gas transmitter with diatomic radicals, is an important regulator of axonal growth and migration, synaptic plasticity, proliferation of neural precursor cells, and neuronal survival. Moreover, NO provides potential anti-inflammation, anti-oxidation, and blood vessel promotion applications. However, excess NO may cause cell death and neuroinflammatory cell damage. The prerequisite for NO treatment of peripheral nerve injury is that it is gradually released over time. In this study, we constructed an injectable NO slow-release system with two main components, including macromolecular NO donor nanoparticles (mPEG-P(MSNO-EG) nanoparticles, NO-NPs) and a carrier for the nanoparticles, mPEG-PA-PP injectable temperature-sensitive hydrogel. Due to the multiple physiological regulation of NO and better physiological barrier penetration, the conduit effectively regulates the inflammatory response and oxidative stress of damaged peripheral nerves, promotes nerve vascularization, and nerve regeneration and docking, accelerating the nerve regeneration process. STATEMENT OF SIGNIFICANCE: The slow regeneration speed of peripheral nerves is mainly due to the destruction of the regeneration microenvironment. Neural conduits with drug delivery capabilities have the potential to improve the microenvironment of nerve regeneration. However, traditional drugs are hindered by the blood nerve barrier and cannot effectively target the injured area. NO, an endogenous gas signaling molecule, can freely cross the blood nerve barrier and act on target cells. However, excessive NO can lead to cell apoptosis. In this study, a NO sustained-release system was constructed to regulate the microenvironment of nerve regeneration through various pathways and promote nerve regeneration.

СОВЕРШЕНСТВОВАНИЕ СИСТЕМЫ РЕМОНТА И ТЕХНИЧЕСКОГО ОБСЛУЖИВАНИЯ ПАССАЖИРСКИХ ВАГОНОВ ДАЛЬНЕГО СООБЩЕНИЯ

The existing systems of maintenance and scheduled preventive maintenance of passenger rolling stock used for long-distance passenger traffic with speeds up to 140 km/h are considered. Promising areas for their improvement are identified. A combined repair system is proposed, which provides a uniform approach of the rolling stock to the position of a single technical audit and scheduled preventive maintenance without taking into account its mileage. The replacement of the element base, when the mileage criteria are met, is carried out on repair and equipment tracks or specially equipped positions during the technical preparation of the rolling stock at the initial point. The proposed system, in comparison with existing ones, reduces the need for depot repairs; the cost of carrying out scheduled repairs of cars, the time spent by cars in an idle fleet, and also provides opportunities for additional operation of the car at the operational stage of the life cycle. Also, the proposed system allows regulating the frequency of the element base replacement of passenger cars with a designated service life of 40 years, including them in the mandatory requirements for the necessary periodic replacement during capital repairs of the car every 5 years.

System reliability modeling and analysis for a marine power equipment operating in a discrete‐time dynamic environment

AbstractExploring on reliability modeling and analysis on a marine equipment in a dynamic environment is a meaningful and challenging issue, because the system commonly carries out the task at sea away from land and suffers a distinct influence of environment. Thus, a reliability model of a multi‐state repairable system operating in dynamic environment is developed by introducing the background of the marine power system in this paper. The novelty of the research lies in the modeling and computing methods are relatively innovative by employing the aggregated stochastic processes, Hadamard production and matrix‐analytic method. First, the working modes of the marine power system under several different kinds of conditions are introduced. Then, the evolution of both the system states and environment are described as discrete‐time Markov chains with multiple and different transition probability matrices. The failure probability and repair probability of components are also distinct in different environments. Furthermore, some performance indexes, especially the index relevant to the environment, are derived, respectively. Finally, the conclusion is obtained by a numerical example of the marine power system, which also illustrates the validity and applicability of the proposed model.

Enhancing genome editing in hPSCs through dual inhibition of DNA damage response and repair pathways

Precise genome editing is crucial for establishing isogenic human disease models and ex vivo stem cell therapy from the patient-derived hPSCs. Unlike Cas9-mediated knock-in, cytosine base editor and prime editor achieve the desirable gene correction without inducing DNA double strand breaks. However, hPSCs possess highly active DNA repair pathways and are particularly susceptible to p53-dependent cell death. These unique characteristics impede the efficiency of gene editing in hPSCs. Here, we demonstrate that dual inhibition of p53-mediated cell death and distinct activation of the DNA damage repair system upon DNA damage by cytosine base editor or prime editor additively enhanced editing efficiency in hPSCs. The BE4stem system comprised of p53DD, a dominant negative p53, and three UNG inhibitor, engineered to specifically diminish base excision repair, improves cytosine base editor efficiency in hPSCs. Addition of dominant negative MLH1 to inhibit mismatch repair activity and p53DD in the conventional prime editor system also significantly enhances prime editor efficiency in hPSCs. Thus, combined inhibition of the distinct cellular cascades engaged in hPSCs upon gene editing could significantly enhance precise genome editing in these cells.

Roles Played by DOCK11, a Guanine Nucleotide Exchange Factor, in HBV Entry and Persistence in Hepatocytes

HBV infection is challenging to cure due to the persistence of viral covalently closed circular viral DNA (cccDNA). The dedicator of cytokinesis 11 (DOCK11) is recognized as a guanine nucleotide exchange factor (GEF) for CDC42 that has been reported to be required for HBV persistence. DOCK11 is expressed in both the cytoplasm and nucleus of human hepatocytes and is functionally associated with retrograde trafficking proteins Arf-GAP with GTPase domain, ankyrin repeat, and pleckstrin homology domain-containing protein 2 (AGAP2), and ADP-ribosylation factor 1 (ARF1), together with the HBV capsid, in the trans-Golgi network (TGN). This opens an alternative retrograde trafficking route for HBV from early endosomes (EEs) to the TGN and then to the endoplasmic reticulum (ER), thereby avoiding lysosomal degradation. DOCK11 also facilitates the association of cccDNA with H3K4me3 and RNA Pol II for activating cccDNA transcription. In addition, DOCK11 plays a crucial role in the host DNA repair system, being essential for cccDNA synthesis. This function can be inhibited by 10M-D42AN, a novel DOCK11-binding peptide, leading to the suppression of HBV replication both in vitro and in vivo. Treatment with a combination of 10M-D42AN and entecavir may represent a promising therapeutic strategy for patients with chronic hepatitis B (CHB). Consequently, DOCK11 may be seen as a potential candidate molecule in the development of molecularly targeted drugs against CHB.

Metagenome mining and functional analysis reveal oxidized guanine DNA repair at the Lost City Hydrothermal Field.

The GO DNA repair system protects against GC → TA mutations by finding and removing oxidized guanine. The system is mechanistically well understood but its origins are unknown. We searched metagenomes and abundantly found the genes encoding GO DNA repair at the Lost City Hydrothermal Field (LCHF). We recombinantly expressed the final enzyme in the system to show MutY homologs function to suppress mutations. Microbes at the LCHF thrive without sunlight, fueled by the products of geochemical transformations of seafloor rocks, under conditions believed to resemble a young Earth. High levels of the reductant H2 and low levels of O2 in this environment raise the question, why are resident microbes equipped to repair damage caused by oxidative stress? MutY genes could be assigned to metagenome-assembled genomes (MAGs), and thereby associate GO DNA repair with metabolic pathways that generate reactive oxygen, nitrogen and sulfur species. Our results indicate that cell-based life was under evolutionary pressure to cope with oxidized guanine well before O2 levels rose following the great oxidation event.

Assessment of Reliability of Power Systems Under Adverse Weather Condition Using Markov System Dynamic Method

Abstract We aim to extend the Markov System Dynamic method (MSD) to evaluate the reliability of repairable systems in two-state weather (2SW) models. Increasing the number of components in real practices has limited the use of the Markov method, because of increasing the number of equations and the complexity of the problem. There is no such restriction in the MSD method. Thus, it can be applied to complex systems. Theoretically, we indicate that the 2SW model is a type of linear dynamical system. Therefore, we can use MSD to solve it. Through an example, the validity of the proposed method is confirmed in comparison to the Markov method for the 2SW model. Since the MSD method does not use equations, it can be a preferred alternative for calculating the reliability of 2SW models. Accordingly, we apply the MSD method for assessing the reliability of a four-component system.

The role of hematopoiesis in bone repair: an update

Purpose of review The repair of bone after injury requires the participation of many different immune cell populations, which are derived from the hematopoietic lineage. The field of osteoimmunology, or the study of the interactions between bone and the immune system, is a growing field with emerging impact on both the basic science and clinical aspects of fracture healing. Recent findings Despite previous focus on the innate immune system in fracture healing, recent studies have revealed an important role for the adaptive immune system in bone repair. The composition of adaptive and innate immune cell populations present at the fracture site is significantly altered during aging and diet-induced obesity, which may contribute to delayed healing. Recent data also suggest a complicated relationship between fracture repair and systemic inflammation, raising the possibility that immune populations from distant sites such as the gut can impact the bone repair process. Summary These findings have important implications for the treatment of fracture patients with antibiotics or anti-inflammatory drugs. Furthermore, the effects of systemic inflammation on fracture repair in the contexts of aging or obesity should be carefully interpreted, as they may not be uniformly detrimental.

Mechanical Testing of Sliding on Pivot-Locking Clamp (SOP-LC) Fracture Repair System in Four-Point Bending and Torsion.

The first objective of this study was to compare the mechanical performance of a straight and contoured rod for the sliding on pivot-locking clamp (SOP-LC) system. The second objective was to compare single-cycle bending and torsion of the SOP-LC rod-bone constructs to a bone gap model between two clamp configurations. First experiment, 5 mm diameter rods from the 3.5 mm SOP-LC system, 4 straight and 4 bent rods were mechanically compared in four-point bending. The second experiment, 8 constructs with clamps on a single side of the rod and 8 constructs with clamps on alternating sides were compared in four-point bending and torsion. A torque limiting screwdriver at 2.5N was used for all constructs. There were not significant differences between the noncontoured versus contoured rods. Constructs with clamps on a single side had a significantly higher yield load, yield displacement and bending strength, but the constructs with alternating clamps had a significantly higher initial torsional stiffness. There were no other significant differences. Mild clamp slippage and mild screw bending were noted in all the torsion tested constructs graphically with multiple stiffness slopes and visually on the post-tested constructs. Torque applied to initial screw placement may play a role in reducing clamp slippage. Although bending yield load, bending yield displacement, bending strength and torsional stiffness were improved by different clamp placement, clinically this will depend on fracture type. Further studies are needed for clinical significance.

Two Septin complexes mediate actin dynamics during cell wound repair

Two Septin complexes mediate actin dynamics during cell wound repair

Wielding a double-edged sword: viruses exploit host DNA repair systems to facilitate replication while bypassing immune activation

Viruses are obligate intracellular pathogens that hijack a myriad of host cell processes to facilitate replication and suppress host antiviral defenses. In its essence, a virus is a segment of foreign nucleic acid that engages host cell machinery to drive viral genome replication, gene transcription, and protein synthesis to generate progeny virions. Because of this, host organisms have developed sophisticated detection systems that activate antiviral defenses following recognition of aberrant nucleic acids. For example, recognition of viral nucleic acids by host DNA repair proteins results in compromised viral genome integrity, induction of antiviral inflammatory programs, cell cycle arrest, and apoptosis. Unsurprisingly, diverse viral families have evolved multiple strategies that fine-tune host DNA repair responses to suppress activation of antiviral defenses while simultaneously hijacking DNA repair proteins to facilitate virus replication. This review summarizes common molecular strategies viruses deploy to exploit host DNA repair mechanisms.

Influence of defect geometry on putty performance in pipeline composite repair assessments

The effective repair of pipelines is crucial to ensuring the integrity of infrastructure. However, the effect of defect geometries on the efficiency of pipeline composite repair systems is a major concern in the industry. This study investigated the effects of geometric properties on the performance of composite repaired pipes and putty components in the context of the efficiency of composite repair systems using parametric analysis with various defect geometries as well as two putty formulations. The study involved the development of a finite element model and the analysis of numerical simulations based on a statistical experimental design matrix. Specifically, a design of experiments approach with a specific emphasis on response surface methodology utilizing the Box–Behnken design was employed to identify factor settings tailored to different defect geometries. The analysis revealed that defect depth, length, and width had a significant negative impact on the strength of putty. Defect depth had a greater impact on the putty performance and steel pipe burst pressure compared to defect length and width. However, defect length and width had mixed influences on putty performance, with different geometries resulting in different responses for both types of putty, indicating the existence of complex interactions between these two parameters. The strength capacity of Putty-A in the repair system was significantly influenced by the interaction between defect width, depth, and length, while Putty-B, the interaction was more significant when it came to length and width of the defect. Further statistical analysis confirmed the individual significance of defect depth, length, and width, as well as their interactions on putty strength capacity. The increased sensitivity of Putty-A to changes in defect geometry compared to Putty-B introduces further complexity to material considerations. These findings highlight the importance of selecting appropriate putty properties depending on the defect geometry for effective pipeline repair. This research provides valuable insights that will guide material selection and the development of new putty material, improving the resilience and reliability of future pipeline repair technologies.

Mechanisms of Heavy Metal Cadmium (Cd)-Induced Malignancy.

The environmental pollution of cadmium is worsening, and its significant carcinogenic effects on humans have been confirmed. Cadmium can induce cancer through various signaling pathways, including the ERK/JNK/p38MAPK, PI3K/AKT/mTOR, NF-κB, and Wnt. It can also cause cancer by directly damaging DNA and inhibiting DNA repair systems, or through epigenetic mechanisms such as abnormal DNA methylation, LncRNA, and microRNA. However, the detailed mechanisms of Cd-induced cancer are still not fully understood and require further investigation.

One-instrument, objective microsatellite instability analysis using high-resolution melt.

In recent years, immune checkpoint inhibitors have proved immense clinical progression in the treatment of certain cancers. The efficacy of immune checkpoint inhibitors is correlated with mismatch repair system deficiency and is exceptionally administered based exclusively on this biological mechanism independent of the cancer type. The promising effect of immune checkpoint inhibitors has left an increasing demand for analytical tools evaluating the mismatch repair status. The analysis of microsatellite instability (MSI), reflecting an indirect but objective manner the inactivation of the mismatch repair system, plays several roles in clinical practice and, therefore, its evaluation is of high relevance. Analysis of MSI by PCR followed by fragment analysis on capillary electrophoresis remains the gold standard method for detection of a deficient mismatch repair system and thereby treatment with immune checkpoint inhibitors. Novel technologies have been applied and concepts such as tumor mutation burden have been introduced. However, to date, most of these technologies require high costs or the need of matched non-tumor tissue as internal comparator. In this study, we present a novel, one-instrument, fast, and objective method for the detection of MSI (MicroSight® MSI 1-step HRM Analysis), which does not depend on the use of matched non-tumor tissue. The assay analyzes five well-described mononucleotide microsatellite sequences by real-time PCR followed by high-resolution melt and evaluates microsatellite length variations via PCR product melting profiles. The assay was evaluated using two different patient cohorts and evaluation included several DNA extraction methodologies, two different PCR platforms, and an inter-laboratory ring study. The MicroSight® MSI assay showed a high repeatability regardless of DNA extraction method and PCR platform, and a 100% agreement of the MSI status with PCR fragment analysis methods applied as clinical comparator.

Crosstalk between DNA Damage Repair and Metabolic Regulation in Hematopoietic Stem Cells.

Self-renewal and differentiation are two characteristics of hematopoietic stem cells (HSCs). Under steady physiological conditions, most primitive HSCs remain quiescent in the bone marrow (BM). They respond to different stimuli to refresh the blood system. The transition from quiescence to activation is accompanied by major changes in metabolism, a fundamental cellular process in living organisms that produces or consumes energy. Cellular metabolism is now considered to be a key regulator of HSC maintenance. Interestingly, HSCs possess a distinct metabolic profile with a preference for glycolysis rather than oxidative phosphorylation (OXPHOS) for energy production. Byproducts from the cellular metabolism can also damage DNA. To counteract such insults, mammalian cells have evolved a complex and efficient DNA damage repair (DDR) system to eliminate various DNA lesions and guard genomic stability. Given the enormous regenerative potential coupled with the lifetime persistence of HSCs, tight control of HSC genome stability is essential. The intersection of DDR and the HSC metabolism has recently emerged as an area of intense research interest, unraveling the profound connections between genomic stability and cellular energetics. In this brief review, we delve into the interplay between DDR deficiency and the metabolic reprogramming of HSCs, shedding light on the dynamic relationship that governs the fate and functionality of these remarkable stem cells. Understanding the crosstalk between DDR and the cellular metabolism will open a new avenue of research designed to target these interacting pathways for improving HSC function and treating hematologic disorders.

THE ‘OSTEOSTASIS’ AND ITS FIVE PRINCIPLES: APPLICATION IN LIMB LENGTHENING

IntroductionHumans Functions (locomotion, protection of organs, reproduction) require a strong support system (bones). The ‘Osteostasis’ is the ability of maintaining the bone structure, its mechanical characteristics and function. Five principles are required for an efficient bone system:Basic Requirements:1) Stability and 2) Function. Repair System (like house building in desert or sea):3) Roads (vessels), 4) Materials (calories, proteins), 5) Workers (bone cells).Analysis of bone problems through these principles bring to optimised treatments.Materials & MethodsMeasurements (>700 lengthening, 32-year follow-up, Full WB Albizzia/G-Nails FWBAG): Bone-DEXA, WB conditions, muscle, fat, etc.Principle-1. Solid bone replacement with a 100% biocompatible and reliable FWBAG with sports (POD0).Principle-2. Bone, Muscle & neural integrity for function Principle-3. Vascular flow lesions induce non-healing (arteriography). Muscle activity accounts for 90% of bone blood flow, ×10 by sports. Required: Checks (arteriography) and treatments (training)Principle-4. Food (NRV Kcal × 2–3, 20–25% proteins).Principle-5. Maintain bone cells and increase them. Suppress ‘opening’, ‘venting’, ‘drainages’.ResultsPrinciple1. Nail fracture (1.2%), nail dysfunction (0%) with FWBAG.Principle2. Intensive sports preop and from POD0 - Principle3. Increased preop vascular supply & muscle force, postop resistance sports fasten recovery. Wheel-chair or low activity decreases healing.Principle4. 6–9 cm circumference loss (non WB-nails or no proper training); 0 cm circumference loss (gain <10 cm) with intense resistance training + high calory intake. - Principle5. Bone cells preservation (no opening, IM saw, increasing bone cells) allow Healing Index down to 8D/cm.ConclusionsThe ‘5P’ allow reaching treatment targets by optimisation of problem solving, maintaining Osteostasis. What would I like or tolerate for me? How can I reach it? Full WB and sports from POD0 was a target 38 years-ago, still not enforced by most of us. Resistance sports, high-calory intake suppress muscle loss and fasten healing, thanks to muscle blood flow and the ‘5P’.

DNA repair is efficient in irradiated M phase zygotes.

In somatic cells, DNA repair is attenuated during mitosis to prevent the formation of anaphase bridges and facilitate the proper segregation of sister chromatids. Irradiation-induced γH2AX foci persist for hours in M phase somatic cells. However, we observed that anaphase bridges formed in a significant fraction of mouse zygotes irradiated during mitosis. Additionally, γH2AX signals in M phase zygotes peaked 30 min after irradiation and subsequently reduced with a half-life within 1-2 h. These results suggest that the DNA repair system may operate efficiently in M phase zygotes following irradiation, leading to the frequent formation of anaphase bridges. The absence of H2AX promoted the successful segregation of sister chromatids and enhanced the development of embryos to the blastocyst stage. The DNA repair system may be differentially regulated during the M phase of the first cell cycle to ensure the immediate elimination of damaged zygotes, thereby efficiently preventing transmission of mutations to subsequent generations.