BACKGROUND: Complications associated with transvenous pacemakers, specifically those involving the lead or subcutaneous pocket, may be avoided with leadless pacemakers (LPs). The safety and efficacy of single-chamber right ventricular LPs have been demonstrated, but their right atrium (RA) use poses new design constraints. OBJECTIVES: The purpose of this study was to evaluate the implant success, electrical performance, and safety of a novel RA LP design in benchtop and preclinical studies. METHODS: A new LP was designed with a dual-helix fixation mechanism specific to the RA anatomy. A 12-week preclinical ovine study was conducted to evaluate implant success, electrical performance, mechanical stability, and safety in vivo, with supporting benchtop measurements to quantify the mechanical forces needed for device retrieval and dislodgment. RESULTS: LPs were successfully implanted in all 10 ovine subjects with no complications. The pacing capture threshold improved significantly over time from implant to week 12 (1.1 ± 0.7 V vs 0.4 ± 0.2 V, P = .008). Sensing amplitudes and pacing impedances were stable from implant to week 12 (4.8 ± 1.8 mV vs 6.0 ± 1.9 mV, P = .160; and 393 ± 77 Ω vs 398 ± 65 Ω, P = .922, respectively). Gross pathology and microscopic histology revealed no adverse interactions and no evidence of device dislodgment or clinically significant myocardial perforation. Benchtop ex vivo porcine atrial tissue measurements revealed greater pull forces required to dislodge the LP vs transvenous active fixation lead (0.42 ± 0.18 lbf vs 0.29 ± 0.08 lbf, P = .020), and greater rotational forces required for deliberate extraction (0.28 ± 0.04 lbf vs 0.14 ± 0.07 lbf, P <.001). CONCLUSION: The novel atrial LP demonstrated successful implantation, with acceptable electrical performance, mechanical stability, and safety in a 12-week preclinical study.

• MeSH
• design vybavení MeSH
• kardiostimulace umělá MeSH
• kardiostimulátor * MeSH
• lidé MeSH
• lipopolysacharidy * MeSH
• ovce MeSH
• prasata MeSH
• protézy a implantáty MeSH
• srdeční síně MeSH
• výsledek terapie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Histone 3 lysine27-to-methionine (H3-K27M) mutations most frequently occur in diffuse midline gliomas (DMGs) of the childhood pons but are also increasingly recognized in adults. Their potential heterogeneity at different ages and midline locations is vastly understudied. Here, through dissecting the single-cell transcriptomic, epigenomic and spatial architectures of a comprehensive cohort of patient H3-K27M DMGs, we delineate how age and anatomical location shape glioma cell-intrinsic and -extrinsic features in light of the shared driver mutation. We show that stem-like oligodendroglial precursor-like cells, present across all clinico-anatomical groups, display varying levels of maturation dependent on location. We reveal a previously underappreciated relationship between mesenchymal cancer cell states and age, linked to age-dependent differences in the immune microenvironment. Further, we resolve the spatial organization of H3-K27M DMG cell populations and identify a mitotic oligodendroglial-lineage niche. Collectively, our study provides a powerful framework for rational modeling and therapeutic interventions.

• MeSH
• dítě MeSH
• gliom * genetika   MeSH
• histony genetika   MeSH
• lidé MeSH
• methionin MeSH
• mutace MeSH
• nádorové mikroprostředí genetika   MeSH
• Racemethionin MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Histone H3.3 glycine 34 to arginine/valine (G34R/V) mutations drive deadly gliomas and show exquisite regional and temporal specificity, suggesting a developmental context permissive to their effects. Here we show that 50% of G34R/V tumors (n = 95) bear activating PDGFRA mutations that display strong selection pressure at recurrence. Although considered gliomas, G34R/V tumors actually arise in GSX2/DLX-expressing interneuron progenitors, where G34R/V mutations impair neuronal differentiation. The lineage of origin may facilitate PDGFRA co-option through a chromatin loop connecting PDGFRA to GSX2 regulatory elements, promoting PDGFRA overexpression and mutation. At the single-cell level, G34R/V tumors harbor dual neuronal/astroglial identity and lack oligodendroglial programs, actively repressed by GSX2/DLX-mediated cell fate specification. G34R/V may become dispensable for tumor maintenance, whereas mutant-PDGFRA is potently oncogenic. Collectively, our results open novel research avenues in deadly tumors. G34R/V gliomas are neuronal malignancies where interneuron progenitors are stalled in differentiation by G34R/V mutations and malignant gliogenesis is promoted by co-option of a potentially targetable pathway, PDGFRA signaling.

• MeSH
• astrocyty metabolismus   patologie   MeSH
• biologické modely MeSH
• buněčný rodokmen MeSH
• chromatin metabolismus   MeSH
• embryo savčí metabolismus   MeSH
• epigeneze genetická MeSH
• genetická transkripce MeSH
• gliom genetika   patologie   MeSH
• histony genetika   metabolismus   MeSH
• interneurony metabolismus   MeSH
• karcinogeneze genetika   patologie   MeSH
• lysin metabolismus   MeSH
• mutace genetika   MeSH
• myši inbrední C57BL MeSH
• nádory mozku genetika   patologie   MeSH
• nervové kmenové buňky metabolismus   MeSH
• oligodendroglie metabolismus   MeSH
• přední mozek embryologie   MeSH
• přeprogramování buněk genetika   MeSH
• promotorové oblasti (genetika) genetika   MeSH
• regulace genové exprese u nádorů MeSH
• růstový faktor odvozený z trombocytů - receptor alfa genetika   metabolismus   MeSH
• stupeň nádoru MeSH
• transkriptom genetika   MeSH
• umlčování genů MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Purpose BRAF V600E is a potentially highly targetable mutation detected in a subset of pediatric low-grade gliomas (PLGGs). Its biologic and clinical effect within this diverse group of tumors remains unknown. Patients and Methods A combined clinical and genetic institutional study of patients with PLGGs with long-term follow-up was performed (N = 510). Clinical and treatment data of patients with BRAF V600E mutated PLGG (n = 99) were compared with a large international independent cohort of patients with BRAF V600E mutated-PLGG (n = 180). Results BRAF V600E mutation was detected in 69 of 405 patients (17%) with PLGG across a broad spectrum of histologies and sites, including midline locations, which are not often routinely biopsied in clinical practice. Patients with BRAF V600E PLGG exhibited poor outcomes after chemotherapy and radiation therapies that resulted in a 10-year progression-free survival of 27% (95% CI, 12.1% to 41.9%) and 60.2% (95% CI, 53.3% to 67.1%) for BRAF V600E and wild-type PLGG, respectively ( P < .001). Additional multivariable clinical and molecular stratification revealed that the extent of resection and CDKN2A deletion contributed independently to poor outcome in BRAF V600E PLGG. A similar independent role for CDKN2A and resection on outcome were observed in the independent cohort. Quantitative imaging analysis revealed progressive disease and a lack of response to conventional chemotherapy in most patients with BRAF V600E PLGG. Conclusion BRAF V600E PLGG constitutes a distinct entity with poor prognosis when treated with current adjuvant therapy.

• MeSH
• diencefalon enzymologie   patologie   MeSH
• dítě MeSH
• gliom enzymologie   genetika   patologie   terapie   MeSH
• kohortové studie MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mutace MeSH
• nádory mozkového kmene enzymologie   genetika   patologie   terapie   MeSH
• nádory mozku enzymologie   genetika   patologie   terapie   MeSH
• předškolní dítě MeSH
• prognóza MeSH
• protoonkogenní proteiny B-raf genetika   MeSH
• stupeň nádoru MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• dítě MeSH
• hematologické nádory MeSH
• kojenec MeSH
• novorozenec MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• novorozenec MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• hematologie a transfuzní lékařství
• onkologie
• pediatrie
• NLK Publikační typ
• kolektivní monografie