Ionizing radiation (IR) is an important environmental risk factor for various cancers and also a major therapeutic agent for cancer treatment. Exposure of mammalian cells to IR induces several types ...of damage to DNA, including double- and single-strand breaks, base and sugar damage, as well as DNA-DNA and DNA-protein cross-links (DPCs). Little is known regarding the biological consequences of DPCs. Identifying the proteins that become cross-linked to DNA by IR would be an important first step in this regard. We have therefore undertaken a proteomics study to isolate and identify proteins involved in IR-induced DPCs. DPCs were induced in AA8 Chinese hamster ovary or GM00637 human fibroblast cells using 0–4 gray of γ-rays under either aerated or hypoxic conditions. DPCs were isolated using a recently developed method, and proteins were identified by mass spectrometry. We identified 29 proteins as being cross-linked to DNA by IR under aerated and/or hypoxic conditions. The identified proteins include structural proteins, actin-associated proteins, transcription regulators, RNA-splicing components, stress-response proteins, cell cycle regulatory proteins, and GDP/GTP-binding proteins. The involvement of several proteins (actin, histone H2B, and others) in DPCs was confirmed by using Western blot analysis. The dose responsiveness of DPC induction was examined by staining one-dimensional SDS-polyacrylamide gels with SYPRO Tangerine followed by analysis using fluorescence imaging. Quantitation of the fluorescence signal indicated no significant difference in total yields of IR-induced DPCs generated under aerated or hypoxic conditions, although differences were observed for several individual protein bands.
To investigate the clinical effectiveness of early foot orthosis intervention for painful correctable valgus deformity of the rearfoot in rheumatoid arthritis (RA).
Patients with RA were randomized ...to receive custom manufactured rigid foot orthoses under podiatry supervision (n = 50) or enter a control group (n = 48). The control group received foot orthoses only when prescribed under normal medical care. Foot pain and disability, using the Foot Function Index (FFI), along with disease activity, tolerance, and adverse reactions, were serially measured over 30 mo continuous treatment.
The group assigned foot orthoses demonstrated an immediate clinical improvement, the effect peaking at 12 mo. At 30 mo the FFI total score was reduced by 23.1% from baseline in the intervention group. Area under the curve analysis showed a statistically significant reduction in FFI scores for total score (p = 0.026), foot pain (p = 0.014), and foot disability (p = 0.016) when intervention was compared to control scores. There were no confounding effects from differences between groups for disease activity or pharmacological or other management strategies. Most patients (96%) used their orthoses and most found them comfortable (97%), although minor adverse reactions, such as tender spots, blisters, and callus, were reported in 30% of patients in the early stages of treatment and persisted in 12% for 30 mo.
Custom designed foot orthoses used continuously over a 30 mo treatment period resulted in a reduction in foot pain by 19.1%, foot disability by 30.8%, and functional limitation by 13.5%. Clinical effectiveness might be enhanced by their use in the early stages of rearfoot pain and deformity.
To evaluate the efficacy of custom foot orthoses for the management of painful rearfoot valgus in patients with rheumatoid arthritis (RA).
Patients were randomized to receive custom-manufactured ...rigid carbon graphite foot orthoses (RA-orthosis) or enter a control group (RA-control) receiving no orthotic intervention. Three-dimensional (3D) kinematics were measured at the ankle joint complex (AJC) using an electromagnetic tracking (EMT) system under barefoot, shod, and orthosis walking conditions. Previously established normal 3D kinematic data were used to descriptively compare motion patterns in both RA groups and statistical analyses were performed on integrals of motion-time for each axis of rotation from data collected at baseline, 3, 6, 12, 18, 24, and 30 months.
Compared with healthy control subjects, all patients with RA demonstrated excessive subtalar joint eversion motion through the stance phase of gait (p < 0.0001) coupled with excessive internal leg rotation (p < 0.0001). Custom-manufactured orthoses significantly reduced eversion through stance (p = 0.009) and re-established equilibrium of motion relative to neutral joint position. Correcting the frontal plane component of the deformity did not lead to a significant reduction in internal leg rotation (p = 0.294). The devices had no effect on tibiotalar dorsiflexion/plantarflexion (p = 0.960). Prospectively, the rigid orthoses maintained and then improved the reduction in cumulative subtalar eversion motion (p < 0.0001). Minimal changes in cumulative subtalar component eversion and internal leg rotation were recorded for both RA groups when walking barefoot but the effect was significantly less for the RA-control group. From 12 months onwards, internal leg rotation started to decrease, suggesting re-coupling of motion, but the overall motion pattern remained abnormal in comparison with normal reference values.
These results support the continuous use of custom-manufactured foot orthoses to correct deformity and optimize AJC function in RA patients with early painful deformity of the rearfoot.
The covalent crosslinking of protein to DNA is a form of DNA damage induced by a number of commonly encountered agents, including metals, aldehydes, and radiation as well as chemotherapeutic drugs. ...DNA–protein crosslinks (DPCs) are potentially bulky and helix distorting and have the potential to block the progression of translocating protein complexes. To fully understand the induction and repair of these lesions, it will be important to identify the crosslinked proteins involved. To take advantage of dramatic improvements in instrument sensitivity that have facilitated the identification of proteins by proteomic approaches, improved methods are required for isolation of DPCs. This article describes a novel method for the isolation of DPCs from mammalian cells that uses chaotropic agents to isolate genomic DNA and stringently remove noncrosslinked proteins followed by DNase I digestion to release covalently crosslinked proteins. This method generates high-quality protein samples in sufficient quantities for analysis by mass spectrometry. In addition, the article presents a modified form of this method that also makes use of chaotropic agents for promoting the adsorption of DNA (with crosslinked proteins) to silica fines, markedly reducing the DPC isolation time and cost. These approaches were applied to radiation- and camptothecin-induced DPCs.
The covalent crosslinking of proteins to DNA presents a major physical challenge to the DNA metabolic machinery. DNA–protein crosslinks (DPCs) are induced by a variety of endogenous and exogenous ...agents (including, paradoxically, agents that are known to cause cancer as well as agents that are used to treat cancer), and yet they have not received as much attention as other types of DNA damage. This review summarizes the current state of knowledge of DPCs in terms of their induction, structures, biological consequences and possible mechanisms of repair. DPCs can be formed through several different chemistries, which is likely to affect the stability and repair of these lesions, as well as their biological consequences. The considerable discrepancy in the DPC literature reflects both the varying chemistries of this heterogeneous group of lesions and the fact that a number of different methods have been used for their analysis. In particular, research in this area has long been hampered by the inability to chemically define these lesions in intact cells and tissues. However, the emergence of proteomics as a tool for identifying specific proteins that become crosslinked to DNA has heralded a new era in our ability to study these lesions. Although there are still many unanswered questions, the identification of specific proteins crosslinked to DNA should facilitate our understanding of the down-stream effects of these lesions.
Abstract
Background
Contemporary management of patients with synchronous colorectal cancer and liver metastases is complex. The aim of this project was to provide a practical framework for care of ...patients with synchronous colorectal cancer and liver metastases, with a focus on terminology, diagnosis, and management.
Methods
This project was a multiorganizational, multidisciplinary consensus. The consensus group produced statements which focused on terminology, diagnosis, and management. Statements were refined during an online Delphi process, and those with 70 per cent agreement or above were reviewed at a final meeting. Iterations of the report were shared by electronic mail to arrive at a final agreed document comprising 12 key statements.
Results
Synchronous liver metastases are those detected at the time of presentation of the primary tumour. The term ‘early metachronous metastases' applies to those absent at presentation but detected within 12 months of diagnosis of the primary tumour, the term ‘late metachronous metastases’ applies to those detected after 12 months. ‘Disappearing metastases’ applies to lesions that are no longer detectable on MRI after systemic chemotherapy. Guidance was provided on the recommended composition of tumour boards, and clinical assessment in emergency and elective settings. The consensus focused on treatment pathways, including systemic chemotherapy, synchronous surgery, and the staged approach with either colorectal or liver-directed surgery as first step. Management of pulmonary metastases and the role of minimally invasive surgery was discussed.
Conclusion
The recommendations of this contemporary consensus provide information of practical value to clinicians managing patients with synchronous colorectal cancer and liver metastases.
This consensus provides a practical framework for the clinician treating patients with synchronous colorectal cancer and liver metastases.
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