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A belt-and-suspenders approach to PNH
Long-term outcomes of cryoballoon versus robotic magnetic navigation guided radiofrequency ablation in patients with persistent atrial fibrillation
New free light chain range decreases LC-MGUS
Impact of red blood cell transfusion in massive burn: a multicenter cohort study
A vision–language foundation model for precision oncology
BRAFV600E induces key features of LCH in iPSCs with cell type–specific phenotypes and drug responses
Abstract Langerhans cell histiocytosis (LCH) is a clonal hematopoietic disorder defined by tumorous lesions containing CD1a+/CD207+ cells. Two severe complications of LCH are systemic hyperinflammation and progressive neurodegeneration. The scarcity of primary samples and lack of appropriate models limit our mechanistic understanding of LCH pathogenesis and affect patient care. We generated a human in vitro model for LCH using induced pluripotent stem cells (iPSCs) harboring the BRAFV600E mutation, the most common genetic driver of LCH. We show that BRAFV600E/WT iPSCs display myelomonocytic skewing during hematopoiesis and spontaneously differentiate into CD1a+/CD207+ cells that are similar to lesional LCH cells and are derived from a CD14+ progenitor. We show that BRAFV600E modulates the expression of key transcription factors regulating monocytic differentiation and leads to an upregulation of proinflammatory molecules and LCH marker genes early during myeloid differentiation. In vitro drug testing revealed that BRAFV600E-induced transcriptomic changes are reverted upon treatment with mitogen-activated protein kinase (MAPK) pathway inhibitors (MAPKis). Importantly, MAPKis do not affect myeloid progenitors but reduce only the mature CD14+ cell population. Furthermore, iPSC-derived neurons (iNeurons) cocultured with BRAFV600E/WT iPSC-derived microglia-like cells, differentiated from iPSC-derived CD34+ progenitors, exhibit signs of neurodegeneration with neuronal damage and release of neurofilament light chain. In summary, the iPSC-based model described here provides a platform to investigate the effects of BRAFV600E in different hematopoietic cell types and provides a tool to compare and identify novel approaches for the treatment of BRAFV600E-driven diseases.
Undergraduate medical students’ perceptions and perspectives on their clinical reasoning learning experiences
How I treat quantitative fibrinogen disorders
Abstract Quantitative fibrinogen disorders, including afibrinogenemia and hypofibrinogenemia, are defined by the complete absence or reduction of fibrinogen, respectively. The diagnosis is based on the measurement of fibrinogen activity and antigen levels, which define the severity of this monogenic disorder. Afibrinogenemia is the result of homozygosity or combined heterozygosity for the causative mutations, whereas monoallelic mutations lead to hypofibrinogenemia. The bleeding phenotype varies in accordance with fibrinogen levels, ranging generally from frequent and often life-threatening bleeding in afibrinogenemia to the absence of symptoms, or mild bleeding symptoms in mild hypofibrinogenemia. The main treatment for quantitative fibrinogen disorders is fibrinogen supplementation. Despite low fibrinogen levels, a tendency for thrombosis is a characteristic of these disorders and may be exacerbated by fibrinogen supplementation. The management of surgery and pregnancy presents significant challenges regarding the amount of fibrinogen replacement and the need for thromboprophylaxis. The objective of this article is to present 4 clinical scenarios that illustrate common clinical challenges and to propose strategies for managing bleeding, thrombosis, surgery, and pregnancy.
Impact of insulin storage and syringe reuse on insulin sterility in diabetes mellitus patients in Mwanza Tanzania
Serum free light chains in a racially diverse population including African Americans and populations from South Africa
Abstract Detection of light chain (LC) monoclonal gammopathies (MGs) traditionally relies on serum free LC (FLC) κ, λ, and their ratio (κ/λ) reference ranges based on a mostly White population. We investigated FLC values in a racially diverse population by screening 10 035 individuals for heavy chain MG, identifying 9028 negative cases whose FLC were measured. Participants included 4149 from the PROMISE study (United States, n = 2383; South Africa, n = 1766) and 4879 from the Mass General Brigham Biobank, with 44% self-identifying as Black. Using standard FLC reference ranges, 1074 of 10 035 individuals (10.7%) were diagnosed with LC monoclonal gammopathy of undetermined significance (MGUS), with 99% being κ-restricted. In the United States, 14.8% of Black and 4% of White individuals were diagnosed (P < .01). Among US participants of African (AFR) and European (EUR) genetic ancestry, 14.4% AFR and 2.9% EUR were diagnosed (P < .01). Among South Africans (100% Black), 27.8% were diagnosed using standard ranges. To avoid overdiagnosis, we propose a new κ/λ ratio reference range (0.686 to 2.10) for populations of AFR descent with normal renal function, with standard values for κ and λ being 7.97 to 77.50 mg/L and 6.20 to 49.20 mg/L, respectively. This reduces LC-MGUS overdiagnosis by 91% (10.7% vs 0.97%). Using the new reference, LC-MGUS accounts for 8.8% of MGUS cases, with 74% being κ-restricted, consistent with LC myeloma rates. These findings highlight the importance of basing disease definitions, such as MGUS, on diverse populations. Adopting our proposed FLC reference values would reduce MGUS overdiagnosis among Black individuals, avoiding unnecessary financial, psychological, and medical consequences. This study includes data from NCT03689595.
Baited traps as flawed proxies for carcass colonization
Abstract In both fundamental and applied sciences, the use of surrogates to measure phenomena that are challenging to study directly is a common practice. However, this requires validating the appropriateness of the surrogates. This study examines if traps, used to measure flight activity of necrophagous flies, can serve as effective surrogates for predicting oviposition on whole carcasses, a topic still under debate in forensic science. We used three sets, a calibration and validation subsets comprising monitoring data of the flight activity of four necrophagous blow fly species, and a test set comprising the oviposition activity of these species on carcasses. Each set also included measurements of abiotic parameters. Using Random Forest for each species, we quantitatively and qualitatively modeled flight activity as a function of abiotic parameters and validated these models. However, when we examined the extent to which flight activity predicted oviposition on carcasses, the models performed poorly, only explaining a fraction of the variance. As the first study making use of small baited trap data to model oviposition on animal carcasses, this study presents mixed results that suggests that traps, despite their utility in addressing various forensic entomology questions, currently appear to be unreliable proxies for predicting carcass colonization.
Oral inflammation and microbiome dysbiosis exacerbate chronic graft-versus-host disease
Abstract The oral microbiota, second in abundance to the gut, is implicated in chronic systemic diseases, but its specific role in graft-versus-host disease (GVHD) pathogenesis has been unclear. Our study finds that mucositis-induced oral dysbiosis in patients after hematopoietic cell transplantation (HCT) associated with increased chronic GVHD (cGVHD), even in patients receiving posttransplant cyclophosphamide. In murine HCT models, oral dysbiosis caused by bilateral molar ligatures exacerbated cGVHD and increased bacterial load in the oral cavity and gut, with Enterococcaceae significantly increasing in both organs. In this model, the migration of Enterococcaceae to cervical lymph nodes both before and after transplantation activated antigen-presenting cells, thereby promoting the expansion of donor-derived inflammatory T cells. Based on these results, we hypothesize that pathogenic bacteria increase in the oral cavity might not only exacerbate local inflammation but also enhance systemic inflammation throughout the HCT course. Additionally, these bacteria translocated to the gut and formed ectopic colonies, further amplifying systemic inflammation. Furthermore, interventions targeting the oral microbiome mitigated murine cGVHD. Collectively, our findings highlight the importance of oral dysbiosis in cGVHD and suggest that modulation of the oral microbiome during transplantation may be an effective approach for preventing or treating cGVHD.
No change in key reef fish herbivores or reef fisher yields in Barbados a decade after the lionfish invasion
Manipulation of the altermagnetic order in CrSb via crystal symmetry
Long-term efficacy and safety of danicopan as add-on therapy to ravulizumab or eculizumab in PNH with significant EVH
Abstract Complement C5 inhibitor treatment with ravulizumab or eculizumab for paroxysmal nocturnal hemoglobinuria (PNH) improves outcomes and survival. Some patients remain anemic due to clinically significant extravascular hemolysis (cs-EVH; hemoglobin [Hb] ≤9.5 g/dL and absolute reticulocyte count [ARC] ≥120 × 109/L). In the phase 3 ALPHA trial, participants received oral factor D inhibitor danicopan (150 mg 3 times daily) or placebo plus ravulizumab or eculizumab during the 12-week, double-blind treatment period 1 (TP1); those receiving placebo switched to danicopan during the subsequent 12-week, open-label TP2 and continued during the 2-year long-term extension (LTE). There were 86 participants randomized in the study, of whom 82 entered TP2, and 80 entered LTE. The primary end point was met, with Hb improvements from baseline at week 12 (least squares mean change, 2.8 g/dL) with danicopan. For participants switching from placebo to danicopan at week 12, improvements in mean Hb were observed at week 24. Similar trends were observed for the proportion of participants with ≥2 g/dL Hb increase, ARC, proportion of participants achieving transfusion avoidance, and Functional Assessment of Chronic Illness Therapy–Fatigue scale scores. Improvements were maintained up to week 72. No new safety signals were observed. The breakthrough hemolysis rate was 6 events per 100 patient-years. These long-term data demonstrate sustained efficacy and safety of danicopan plus ravulizumab/eculizumab for continued control of terminal complement activity, intravascular hemolysis, and cs-EVH in PNH. This trial was registered at www.clinicaltrials.gov as #NCT04469465.