Psoralen-induced DNA adducts are substrates for the base excision repair pathway in human cells

Interstrand cross-link (ICL) is a covalent modification of both strands of DNA, which prevents DNA strand separation during transcription and replication. Upon photoactivation 8-methoxypsoralen (8-MOP+UVA) alkylates both strands of DNA duplex at the 5,6-double bond of thymidines, generating monoadducts (MAs) and ICLs. It was thought that bulky DNA lesions such as MAs are eliminated only in the nucleotide excision repair pathway. Instead, non-bulky DNA lesions are substrates for DNA glycosylases and AP endonucleases which initiate the base excision repair (BER) pathway. Here we examined whether BER might be involved in the removal of psoralen–DNA photoadducts. The results show that in human cells DNA glycosylase NEIL1 excises the MAs in duplex DNA, subsequently the apurinic/apyrimidinic endonuclease 1, APE1, removes the 3′-phosphate residue at single-strand break generated by NEIL1. The apparent kinetic parameters suggest that NEIL1 excises MAs with high efficiency. Consistent with these results HeLa cells lacking APE1 and/or NEIL1 become hypersensitive to 8-MOP+UVA exposure. Furthermore, we demonstrate that bacterial homologues of NEIL1, the Fpg and Nei proteins, also excise MAs. New substrate specificity of the Fpg/Nei protein family provides an alternative repair pathway for ICLs and bulky DNA damage

7,8-Dihydro-8-oxoadenine, a highly mutagenic adduct, is repaired by Escherichia coli and human mismatch-specific uracil/thymine-DNA glycosylases

Hydroxyl radicals predominantly react with the C(8) of purines forming 7,8-dihydro-8-oxoguanine (8oxoG) and 7,8-dihydro-8-oxoadenine (8oxoA) adducts, which are highly mutagenic in mammalian cells. The majority of oxidized DNA bases are removed by DNA glycosylases in the base excision repair pathway. Here, we report for the first time that human thymine-DNA glycosylase (hTDG) and Escherichia coli mismatch-specific uracil-DNA glycosylase (MUG) can remove 8oxoA from 8oxoA*T, 8oxoA*G and 8oxoA*C pairs. Comparison of the kinetic parameters of the reaction indicates that full-length hTDG excises 8oxoA, 3,N(4)-ethenocytosine (epsilonC) and T with similar efficiency (k(max) = 0.35, 0.36 and 0.16 min(-1), respectively) and is more proficient as compared with its bacterial homologue MUG. The N-terminal domain of the hTDG protein is essential for 8oxoA-DNA glycosylase activity, but not for epsilonC repair. Interestingly, the TDG status had little or no effect on the proliferation rate of mouse embryonic fibroblasts after exposure to gamma-irradiation. Nevertheless, using whole cell-free extracts from the DNA glycosylase-deficient murine embryonic fibroblasts and E. coli, we demonstrate that the excision of 8oxoA from 8oxoA*T and 8oxoA*G has an absolute requirement for TDG and MUG, respectively. The data establish that MUG and TDG can counteract the genotoxic effects of 8oxoA residues in vivo

7,8-dihydro-8-oxoadenine, a highly mutagenic adduct, is repaired by Escherichia coli and human mismatch-specific uracil/thymine-DNA glycosylases

Hydroxyl radicals predominantly react with the C8 of purines forming 7,8-dihydro-8-oxoguanine (8oxoG) and 7,8-dihydro-8-oxoadenine (8oxoA) adducts, which are highly mutagenic in mammalian cells. The majority of oxidized DNA bases are removed by DNA glycosylases in the base excision repair pathway. Here, we report for the first time that human thymine-DNA glycosylase (hTDG) and Escherichia coli mismatch-specific uracil-DNA glycosylase (MUG) can remove 8oxoA from 8oxoA•T, 8oxoA•G and 8oxoA•C pairs. Comparison of the kinetic parameters of the reaction indicates that full-length hTDG excises 8oxoA, 3,N4-ethenocytosine (εC) and T with similar efficiency (kmax = 0.35, 0.36 and 0.16 min−1, respectively) and is more proficient as compared with its bacterial homologue MUG. The N-terminal domain of the hTDG protein is essential for 8oxoA-DNA glycosylase activity, but not for εC repair. Interestingly, the TDG status had little or no effect on the proliferation rate of mouse embryonic fibroblasts after exposure to γ-irradiation. Nevertheless, using whole cell-free extracts from the DNA glycosylase-deficient murine embryonic fibroblasts and E. coli, we demonstrate that the excision of 8oxoA from 8oxoA•T and 8oxoA•G has an absolute requirement for TDG and MUG, respectively. The data establish that MUG and TDG can counteract the genotoxic effects of 8oxoA residues in viv

Aberrant repair initiated by mismatch-specific thymine-DNA glycosylases provides a mechanism for the mutational bias observed in CpG islands

The human thymine-DNA glycosylase (TDG) initiates the base excision repair (BER) pathway to remove spontaneous and induced DNA base damage. It was first biochemically characterized for its ability to remove T mispaired with G in CpG context. TDG is involved in the epigenetic regulation of gene expressions by protecting CpG-rich promoters from de novo DNA methylation. Here we demonstrate that TDG initiates aberrant repair by excising T when it is paired with a damaged adenine residue in DNA duplex. TDG targets the non-damaged DNA strand and efficiently excises T opposite of hypoxanthine (Hx), 1,N6-ethenoadenine, 7,8-dihydro-8-oxoadenine and abasic site in TpG/CpX context, where X is a modified residue. In vitro reconstitution of BER with duplex DNA containing Hx•T pair and TDG results in incorporation of cytosine across Hx. Furthermore, analysis of the mutation spectra inferred from single nucleotide polymorphisms in human population revealed a highly biased mutation pattern within CpG islands (CGIs), with enhanced mutation rate at CpA and TpG sites. These findings demonstrate that under experimental conditions used TDG catalyzes sequence context-dependent aberrant removal of thymine, which results in TpG, CpA→CpGmutations, thus providing a plausible mechanism for the putative evolutionary origin of the CGIs in mammalian genomes

Complexity assessment and technical aspect of coronary angiogram and percutaneous coronary intervention following transcatheter aortic valve implantation

Background: Performing selective coronary angiogram (CA) and percutaneous coronary intervention (PCI) post transcatheter aortic valve implantation (TAVI) may be challenging with various success rates of coronary ostia engagement. Methods: Among all patients who underwent CA and/or PCI after TAVI from our single center TAVI registry, ostia cannulation success was reported according to the quality of ostia engagement and artery opacification, and was classified as either selective, partially selective or non-selective but sufficient for diagnosis. Results: Among the 424 consecutive TAVI procedures performed at the aforementioned institution, 20 (4.7%) CA were performed in 19 (4.5%) patients at a median time of 464 days post TAVI (25–75% IQ: 213–634 days). CA were performed in 7 CoreValve, 9 Evolut R, 1 Evolut PRO and 2 Edwards Sapien 3 devices. Transradial vascular approach was attempted in 9 procedures (45%, right n = 6 and left n = 3) and was successful in 8 (40%) patients. A total of 20 left main artery ostium cannulation were attempted leading to a diagnostic CA in all of them with selective engagement in 65%.  Engagement of the right coronary artery in 2 out of 15 attempted cases failed due to a low ostium in conjunction with a high implantation of a CoreValve prosthesis. 11 PCI (55% of CA) including 2 left main lesions were performed. In 4 patients (36.4% of the PCI), an extension catheter was required to engage the left main. All planned PCI were successful. Conclusions: Post TAVI CA and PCI are challenging but feasible even after supra-annular self-expandable valve implantation

The Arginine Methyltransferase Carm1 is Necessary for Heart Development

To discover genes implicated in human congenital disorders, we performed ENU mutagenesis in the mouse and screened for mutations affecting embryonic development. In this work we report defects of heart development in mice homozygous for a mutation of Coactivator-associated Arginine Methyltransferase 1 (Carm1). While Carm1 has been extensively studied, it has never been previously associated with a role in heart development. Phenotype analysis combining histology and micro-computed tomography (micro-CT) imaging shows a range of cardiac defects. Most notably, many affected mid-gestation embryos appear to have cardiac rupture and hemorrhaging in the thorax. Mice that survive to late gestation show a variety of cardiac defects, including Ventricular Septal Defects (VSDs), Double Outlet Right Ventricle (DORV), and Persistent Truncus Arteriosus (PTA). Transcriptome analyses of the mutant embryos by mRNA-seq reveal the perturbation of several genes involved in cardiac morphogenesis and muscle development and function. In addition, we observe the mis-localization of cardiac neural crest cells at E12.5 in the outflow tract. The cardiac phenotype of Carm1 mutant embryos is similar to that of Pax3 null mutants, and PAX3 is a putative target of CARM1. However, our analysis does not support the hypothesis that developmental defects in Carm1 mutant embryos are primarily due to a functional defect of PAX3

Post-transplant cyclophosphamide prevents xenogeneic graft-versus-host disease while depleting proliferating regulatory T cells

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Pseudomonas aeruginosa bloodstream infections in patients with cancer: differences between patients with hematological malignancies and solid tumors

Objectives: To assess the clinical features and outcomes of Pseudomonas aeruginosa bloodstream infection (PA BSI) in neutropenic patients with hematological malignancies (HM) and with solid tumors (ST), and identify the risk factors for 30-day mortality. Methods: We performed a large multicenter, retrospective cohort study including onco-hematological neutropenic patients with PA BSI conducted across 34 centers in 12 countries (January 2006-May 2018). Episodes occurring in hematologic patients were compared to those developing in patients with ST. Risk factors associated with 30-day mortality were investigated in both groups. Results: Of 1217 episodes of PA BSI, 917 occurred in patients with HM and 300 in patients with ST. Hematological patients had more commonly profound neutropenia (0.1 × 109 cells/mm) (67% vs. 44.6%; p < 0.001), and a high risk Multinational Association for Supportive Care in Cancer (MASCC) index score (32.2% vs. 26.7%; p = 0.05). Catheter-infection (10.7% vs. 4.7%; p = 0.001), mucositis (2.4% vs. 0.7%; p = 0.042), and perianal infection (3.6% vs. 0.3%; p = 0.001) predominated as BSI sources in the hematological patients, whereas pneumonia (22.9% vs. 33.7%; p < 0.001) and other abdominal sites (2.8% vs. 6.3%; p = 0.006) were more common in patients with ST. Hematological patients had more frequent BSI due to multidrug-resistant P. aeruginosa (MDRPA) (23.2% vs. 7.7%; p < 0.001), and were more likely to receive inadequate initial antibiotic therapy (IEAT) (20.1% vs. 12%; p < 0.001). Patients with ST presented more frequently with septic shock (45.8% vs. 30%; p < 0.001), and presented worse outcomes, with increased 7-day (38% vs. 24.2%; p < 0.001) and 30-day (49% vs. 37.3%; p < 0.001) case-fatality rates. Risk factors for 30-day mortality in hematologic patients were high risk MASCC index score, IEAT, pneumonia, infection due to MDRPA, and septic shock. Risk factors for 30-day mortality in patients with ST were high risk MASCC index score, IEAT, persistent BSI, and septic shock. Therapy with granulocyte colony-stimulating factor was associated with survival in both groups. Conclusions: The clinical features and outcomes of PA BSI in neutropenic cancer patients showed some differences depending on the underlying malignancy. Considering these differences and the risk factors for mortality may be useful to optimize their therapeutic management. Among the risk factors associated with overall mortality, IEAT and the administration of granulocyte colony-stimulating factor were the only modifiable variables.Funding: This study was supported by the Instituto de Salud Carlos III, Subdirección General de Redes y Centros de Investigación Cooperativa, Ministerio de Economía, Industria y Competitividad, Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC) (CB21/13/00009; CB21/13/00079; CB21/13/00054; CB21/13/00086), Madrid, Spain. Acknowledgments: We thank the ESCMID Study Group for Bloodstream Infections, Endocarditis, and Sepsis (ESGBIES) and the ESCMID Study Group for Immunocompromised Hosts (ESGICH) for supporting the study. We thank the Centres de Recerca de Catalunya (CERCA) Program and Generalitat de Catalunya for the institutional support. We thank the Spanish Network for Research in Infectious Diseases and the Río Hortega program of the Instituto de Salud Carlos III for the financial support of pre-doctoral student J. Laporte-Amargós and A. Bergas

Provision of mental health and psychosocial support services to health workers and community members in conflict-affected Northwest Syria: a mixed-methods study

From Springer Nature via Jisc Publications RouterHistory: received 2023-06-23, registration 2023-09-28, accepted 2023-09-28, epub 2023-10-04, online 2023-10-04, collection 2023-12Acknowledgements: We also acknowledge the contribution of WHO Attacks on Health Care Initiative to the conception and co-funding of this study and ReBUILD for Resilience (R4R) for supporting some of the staff time and the publication cost. We thank the ‘Humanitarian Initiative Organization’ (HIA) for their support in data collection.Publication status: PublishedFunder: World Health Organization; doi: http://dx.doi.org/10.13039/100004423Background: Northwest Syria (NWS) is a conflict area with challenging political, economic, demographic and social dynamics. The region has a high number of internally displaced persons with increasingly disrupted delivery of basic services, including healthcare. Mental health needs have been increasing in the region while the infrastructure and capacity of the health sector has been negatively affected by the conflict. This study aimed to explore the provision of mental health and psychosocial support (MHPSS) services to communities in NWS (including healthcare workers) and to assess the experiences of beneficiaries with MHPSS services. Methods: The study followed a mixed-methods research design that included qualitative and participatory methods (44 semi-structured interviews and a group model building workshop with 15 participants) as well as a survey with 462 beneficiaries. Results: Findings suggested an improvement of MHPSS services in the region over the last few years due to the creation of a specific Technical Working Group for MHPSS that contributed to assessment of community needs and support of the MHPSS response. The key elements of this response were: (1) training non-specialized health workers to address the shortage in specialized providers; (2) securing funding and coordination of services between different organizations; and (3) addressing gaps in the availability and geographical distribution of other needed resources, such as medicines. While those elements contributed to improving access to services and the quality of services—especially among health workers seeking MHPSS services—findings suggested gaps in the sustainability of services and a need to scale up those interventions in an integrated approach. Conclusion: The study findings add to the evidence base on the challenges in scaling up MHPSS interventions and their long-term sustainability concerns. Priority actions should address the intermittent funding of the MHPSS response, incorporate MHPSS outputs and outcomes in the reimbursement of routine services, improve coordination between health partners and non-health actors in order to expand the scope of MHPSS response, and address the inequitable availability of resources in the region.pubpu

Evaluating telehealth lifestyle therapy versus telehealth psychotherapy for reducing depression in adults with COVID-19 related distress: the curbing anxiety and depression using lifestyle medicine (CALM) randomised non-inferiority trial protocol

BACKGROUND: There is increasing recognition of the substantial burden of mental health disorders at an individual and population level, including consequent demand on mental health services. Lifestyle-based mental healthcare offers an additional approach to existing services with potential to help alleviate system burden. Despite the latest Royal Australian New Zealand College of Psychiatrists guidelines recommending that lifestyle is a ‘first-line’, ‘non-negotiable’ treatment for mood disorders, few such programs exist within clinical practice. Additionally, there are limited data to determine whether lifestyle approaches are equivalent to established treatments. Using an individually randomised group treatment design, we aim to address this gap by evaluating an integrated lifestyle program (CALM) compared to an established therapy (psychotherapy), both delivered via telehealth. It is hypothesised that the CALM program will not be inferior to psychotherapy with respect to depressive symptoms at 8 weeks. METHODS: The study is being conducted in partnership with Barwon Health’s Mental Health, Drugs & Alcohol Service (Geelong, Victoria), from which 184 participants from its service and surrounding regions are being recruited. Eligible participants with elevated psychological distress are being randomised to CALM or psychotherapy. Each takes a trans-diagnostic approach, and comprises four weekly (weeks 1-4) and two fortnightly (weeks 6 and 8) 90-min, group-based sessions delivered via Zoom (digital video conferencing platform). CALM focuses on enhancing knowledge, behavioural skills and support for improving dietary and physical activity behaviours, delivered by an Accredited Exercise Physiologist and Accredited Practising Dietitian. Psychotherapy uses cognitive behavioural therapy (CBT) delivered by a Psychologist or Clinical Psychologist, and Provisional Psychologist. Data collection occurs at baseline and 8 weeks. The primary outcome is depressive symptoms (assessed via the Patient Health Questionnaire-9) at 8 weeks. Societal and healthcare costs will be estimated to determine the cost-effectiveness of the CALM program. A process evaluation will determine its reach, adoption, implementation and maintenance. DISCUSSION: If the CALM program is non-inferior to psychotherapy, this study will provide the first evidence to support lifestyle-based mental healthcare as an additional care model to support individuals experiencing psychological distress. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12621000387820, Registered 8 April 2021