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Objective: As the prevalence of neuroendovascular interventions increases, it is critical to mitigate unnecessary radiation for patients, providers, and health care staff. Our group previously demonstrated reduced radiation dose and exposure during diagnostic angiography by reducing the default pulse and frame rates. We applied the same technique for basic neuroendovascular interventions. Methods: We performed a retrospective review of prospectively acquired data after implementing a quality improvement protocol in which pulse rate and frame rate were reduced from 15 p/s to 7.5 p/s and 7.5 f/s to 4.0 f/s respectively. We studied consecutive, unilateral middle meningeal artery embolizations treated with particles. Total radiation dose, radiation per angiographic run, total radiation exposure, and exposure per run were calculated. Multivariable log-linear regression was performed to account for patient body mass index (BMI), number of angiographic runs, and number of vessels catheterized. Results: A total of 20 consecutive, unilateral middle meningeal artery embolizations were retrospectively analyzed. The radiation reduction protocol was associated with a 39.2% decrease in the total radiation dose and a 37.1% decrease in radiation dose per run. The protocol was associated with a 41.6% decrease in the total radiation exposure and a 39.5% decrease in exposure per run. Conclusions: Radiation reduction protocols can be readily applied to neuroendovascular interventions without increasing overall fluoroscopy time and reduce radiation dose and exposure by 39.2% and 41.6% respectively. We strongly encourage all interventionalists to be cognizant of pulse rate and frame rate when performing routine interventions.
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BACKGROUND: Acute tandem occlusions (TOs) are challenging to treat. Although acute carotid stenting of the proximal lesion is well tolerated, there are certain situations when the practitioner may be wary of acute stenting (bleeding concerns). OBJECTIVE: The purpose of this study was to retrospectively study patients with tandem occlusions who had re-occlusion of the extracranial ICA and develop a Circle of Willis Score (COWS) to help predict which patients could forego acute stenting. METHODS: This is a retrospective review of TO patients with a persistent proximal occlusion following intervention (either expected or unexpected). Pre intervention CTA and intraoperative DSA were reviewed, and each patient was assigned a score 2 (complete COW), 1a (patent A1-Acomm-A1), 1p (patent Pcomm), or 0 (incomplete COW). Findings from the DSA took precedence over the CTA. Two cohorts were created, the complete COW cohort (COWS 2) versus the incomplete COW cohort (COWS 1a,1p, or 0). Angiographic outcomes were assessed using the mTICI score (2b-3) and clinical outcomes were assessed using discharge mRS (good outcome mRS 0-3). RESULTS: Of 68 TO cases, 12 had persistent proximal occlusions. There were 5/12 (42 %) patients in the complete COW cohort, and 7/12 (58 %) in the incomplete COW cohort (5/12 with scores of 1a/1p and 2/12 with a score of 0). In the complete COW cohort, there were 2 ICA-ICA and 3 ICA-MCA occlusions. In the incomplete COW cohort, there was one ICA-ICA occlusion and 6 ICA-MCA occlusions. LKW-puncture was shorter in the complete COW cohort (208 min vs. 464 min, p = 0.16). Successful reperfusion was higher in the complete COW cohort (100 % vs. 71 %). There was a trend toward better clinical outcomes in the complete COW cohort (80 % vs 29 %, p = 0.079). CONCLUSION: The COWS is a simple score that may help predict a successful clinical outcome without proximal revascularization when concerned about performing an acute carotid stent during TO treatment. Evaluation in larger TO cohort is warranted.
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Procedimentos Endovasculares , Acidente Vascular Cerebral , Humanos , Acidente Vascular Cerebral/cirurgia , Artéria Carótida Interna/diagnóstico por imagem , Artéria Carótida Interna/cirurgia , Estudos Retrospectivos , Círculo Arterial do Cérebro/diagnóstico por imagem , Círculo Arterial do Cérebro/cirurgia , Resultado do Tratamento , Tomada de Decisões , Stents , TrombectomiaRESUMO
Intraorbital arteriovenous fistulas (IOAVFs) are rare vascular pathologies that may be effectively treated with direct puncture (DP) of the venous supply and may offer a definitive and safe cure when done under ultrasound or stereotactic guidance. Here we present three new cases of DP treatment of IOAVFs, indications for safe use, and their potential complications in comparison to the existing literature on DP and other modalities.Three patients with IOAVFs were treated with DP with ultrasound guidance, stereotactic guidance, and fluoroscopy. Final digital subtraction angiography (DSA) revealed complete cure of IOAVFs. A literature review via PubMed was performed on treatments of IOAVFs since 1978.All three cases of DP resulted in successful cures with 2/3 cases resulting in complications from orbital hematoma formation. 49 total treatments including the cases herein have been documented. DP treatment constituted 5/49, conservative management 17/49, transarterial 8/49, transvenous 18/49, and surgical 3/49. Some cases received more than one mode of treatment. Transarterial and surgical managements were found to have higher complication rates than transvenous and DP.DP is a safe and effective treatment of IOAVFs that can be performed via multiple image guided methods and guarantees a definitive cure. Orbital hematomas are a potential complication of which operators should be aware.
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OBJECTIVE: Diagnostic cerebral angiograms (DCAs) are widely used in neurosurgery due to their high sensitivity and specificity to diagnose and characterize pathology using ionizing radiation. Eliminating unnecessary radiation is critical to reduce risk to patients, providers, and health care staff. We investigated if reducing pulse and frame rates during routine DCAs would decrease radiation burden without compromising image quality. METHODS: We performed a retrospective review of prospectively acquired data after implementing a quality improvement protocol in which pulse rate and frame rate were reduced from 15 p/s to 7.5 p/s and 7.5 f/s to 4.0 f/s respectively. Radiation doses and exposures were calculated. Two endovascular neurosurgeons reviewed randomly selected angiograms of both doses and blindly assessed their quality. RESULTS: A total of 40 consecutive angiograms were retrospectively analyzed, 20 prior to the protocol change and 20 after. After the intervention, radiation dose, radiation per run, total exposure, and exposure per run were all significantly decreased even after adjustment for BMI (all p<0.05). On multivariable analysis, we identified a 46% decrease in total radiation dose and 39% decrease in exposure without compromising image quality or procedure time. CONCLUSIONS: We demonstrated that for routine DCAs, pulse rate of 7.5 with a frame rate of 4.0 is sufficient to obtain diagnostic information without compromising image quality or elongating procedure time. In the interest of patient, provider, and health care staff safety, we strongly encourage all interventionalists to be cognizant of radiation usage to avoid unnecessary radiation exposure and consequential health risks.
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PURPOSE: Glioblastoma represents the most common primary brain tumor. Although antiangiogenics are used in the recurrent setting, they do not prolong survival. Glioblastoma is known to upregulate fatty acid synthase (FASN) to facilitate lipid biosynthesis. TVB-2640, a FASN inhibitor, impairs this activity. PATIENTS AND METHODS: We conducted a prospective, single-center, open-label, unblinded, phase II study of TVB-2640 plus bevacizumab in patients with recurrent high-grade astrocytoma. Patients were randomly assigned to TVB-2640 (100 mg/m2 oral daily) plus bevacizumab (10 mg/kg i.v., D1 and D15) or bevacizumab monotherapy for cycle 1 only (28 days) for biomarker analysis. Thereafter, all patients received TVB-2640 plus bevacizumab until treatment-related toxicity or progressive disease (PD). The primary endpoint was progression-free survival (PFS). RESULTS: A total of 25 patients were enrolled. The most frequently reported adverse events (AE) were palmar-plantar erythrodysesthesia, hypertension, mucositis, dry eye, fatigue, and skin infection. Most were grade 1 or 2 in intensity. The overall response rate (ORR) for TVB-2640 plus bevacizumab was 56% (complete response, 17%; partial response, 39%). PFS6 for TVB-2640 plus bevacizumab was 31.4%. This represented a statistically significant improvement in PFS6 over historical bevacizumab monotherapy (BELOB 16%; P = 0.008) and met the primary study endpoint. The observed OS6 was 68%, with survival not reaching significance by log-rank test (P = 0.56). CONCLUSIONS: In this phase II study of relapsed high-grade astrocytoma, TVB-2640 was found to be a well-tolerated oral drug that could be safely combined with bevacizumab. The favorable safety profile and response signals support the initiation of a larger multicenter trial of TVB-2640 plus bevacizumab in astrocytoma.
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Glioblastoma , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Bevacizumab/efeitos adversos , Doença Crônica , Intervalo Livre de Doença , Glioblastoma/tratamento farmacológico , Recidiva Local de Neoplasia/patologia , Estudos Prospectivos , RecidivaRESUMO
DNMT1 maintains the parental DNA methylation pattern on newly replicated hemimethylated DNA. The failure of this maintenance process causes aberrant DNA methylation that affects transcription and contributes to the development and progression of cancers such as acute myeloid leukemia. Here, we structurally characterized a set of newly discovered DNMT1-selective, reversible, non-nucleoside inhibitors that bear a core 3,5-dicyanopyridine moiety, as exemplified by GSK3735967, to better understand their mechanism of inhibition. All of the dicyanopydridine-containing inhibitors examined intercalate into the hemimethylated DNA between two CpG base pairs through the DNA minor groove, resulting in conformational movement of the DNMT1 active-site loop. In addition, GSK3735967 introduces two new binding sites, where it interacts with and stabilizes the displaced DNMT1 active-site loop and it occupies an open aromatic cage in which trimethylated histone H4 lysine 20 is expected to bind. Our work represents a substantial step in generating potent, selective, and non-nucleoside inhibitors of DNMT1.
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DNA (Citosina-5-)-Metiltransferases , Metilação de DNA , Sítios de Ligação , Domínio Catalítico , DNA/metabolismo , DNA (Citosina-5-)-Metiltransferases/química , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismoRESUMO
DNA methylation, a key epigenetic driver of transcriptional silencing, is universally dysregulated in cancer. Reversal of DNA methylation by hypomethylating agents, such as the cytidine analogs decitabine or azacytidine, has demonstrated clinical benefit in hematologic malignancies. These nucleoside analogs are incorporated into replicating DNA where they inhibit DNA cytosine methyltransferases DNMT1, DNMT3A and DNMT3B through irreversible covalent interactions. These agents induce notable toxicity to normal blood cells thus limiting their clinical doses. Herein we report the discovery of GSK3685032, a potent first-in-class DNMT1-selective inhibitor that was shown via crystallographic studies to compete with the active-site loop of DNMT1 for penetration into hemi-methylated DNA between two CpG base pairs. GSK3685032 induces robust loss of DNA methylation, transcriptional activation and cancer cell growth inhibition in vitro. Due to improved in vivo tolerability compared with decitabine, GSK3685032 yields superior tumor regression and survival mouse models of acute myeloid leukemia.
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Azacitidina , Leucemia Mieloide Aguda , Animais , Azacitidina/farmacologia , DNA/metabolismo , Metilação de DNA , Metilases de Modificação do DNA/genética , Decitabina/farmacologia , Leucemia Mieloide Aguda/tratamento farmacológico , CamundongosRESUMO
Ruptured choroidal microaneurysms associated with moyamoya syndrome are rare entities. Their small size and deep/distal location make them challenging to treat. Both surgical and endovascular treatment options carry significant risk of stroke. Here we present a two-patient case report of ruptured choroidal microaneurysms treated with Nbutyl cyanoacrylate (nBCA) endovascular embolization utilizing neuromonitoring and provocative testing during one of the cases. We also present a review of the literature evaluating surgical and endovascular treatment of these aneurysms.
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Aneurisma Roto/terapia , Embolização Terapêutica , Procedimentos Endovasculares , Aneurisma Intracraniano/terapia , Doença de Moyamoya/complicações , Adulto , Aneurisma Roto/diagnóstico por imagem , Aneurisma Roto/etiologia , Feminino , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/etiologia , Masculino , Doença de Moyamoya/diagnóstico por imagem , Resultado do TratamentoRESUMO
DNA adenine methylation by Caulobacter crescentus Cell Cycle Regulated Methyltransferase (CcrM) is an important epigenetic regulator of gene expression. The recent CcrM-DNA cocrystal structure shows the CcrM dimer disrupts four of the five base pairs of the (5'-GANTC-3') recognition site. We developed a fluorescence-based assay by which Pyrrolo-dC tracks the strand separation event. Placement of Pyrrolo-dC within the DNA recognition site results in a fluorescence increase when CcrM binds. Non-cognate sequences display little to no fluorescence changes, showing that strand separation is a specificity determinant. Conserved residues in the C-terminal segment interact with the phospho-sugar backbone of the non-target strand. Replacement of these residues with alanine results in decreased methylation activity and changes in strand separation. The DNA recognition mechanism appears to occur with the Type II M.HinfI DNA methyltransferase and an ortholog of CcrM, BabI, but not with DNA methyltransferases that lack the conserved C-terminal segment. The C-terminal segment is found broadly in N4/N6-adenine DNA methyltransferases, some of which are human pathogens, across three Proteobacteria classes, three other phyla and in Thermoplasma acidophilum, an Archaea. This Pyrrolo-dC strand separation assay should be useful for the study of other enzymes which likely rely on a strand separation mechanism.
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Caulobacter crescentus/enzimologia , DNA Metiltransferases Sítio Específica (Adenina-Específica)/química , DNA Metiltransferases Sítio Específica (Adenina-Específica)/metabolismo , Motivos de Aminoácidos , Caulobacter crescentus/citologia , DNA/química , Metilação de DNA , Desoxicitidina/análogos & derivados , Fluorescência , Mutação , Fenótipo , Ligação Proteica , Pirróis , Alinhamento de Sequência , DNA Metiltransferases Sítio Específica (Adenina-Específica)/genéticaRESUMO
Meiotic crossovers result from homology-directed repair of DNA double-strand breaks (DSBs). Unlike yeast and plants, where DSBs are generated near gene promoters, in many vertebrates DSBs are enriched at hotspots determined by the DNA binding activity of the rapidly evolving zinc finger array of PRDM9 (PR domain zinc finger protein 9). PRDM9 subsequently catalyzes tri-methylation of lysine 4 and lysine 36 of Histone H3 in nearby nucleosomes. Here, we identify the dual histone methylation reader ZCWPW1, which is tightly co-expressed during spermatogenesis with Prdm9, as an essential meiotic recombination factor required for efficient repair of PRDM9-dependent DSBs and for pairing of homologous chromosomes in male mice. In sum, our results indicate that the evolution of a dual histone methylation writer/reader (PRDM9/ZCWPW1) system in vertebrates remodeled genetic recombination hotspot selection from an ancestral static pattern near genes towards a flexible pattern controlled by the rapidly evolving DNA binding activity of PRDM9.
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Proteínas de Ciclo Celular/metabolismo , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Histona-Lisina N-Metiltransferase/metabolismo , Meiose , Espermatócitos/enzimologia , Espermatogênese , Animais , Azoospermia/enzimologia , Azoospermia/genética , Azoospermia/patologia , Proteínas de Ciclo Celular/deficiência , Proteínas de Ciclo Celular/genética , Bases de Dados Genéticas , Evolução Molecular , Histona-Lisina N-Metiltransferase/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Espermatócitos/patologiaRESUMO
Two DNA methyltransferases, Dam and ß-class cell cycle-regulated DNA methyltransferase (CcrM), are key mediators of bacterial epigenetics. CcrM from the bacterium Caulobacter crescentus (CcrM C. crescentus, methylates adenine at 5'-GANTC-3') displays 105-107-fold sequence discrimination against noncognate sequences. However, the underlying recognition mechanism is unclear. Here, CcrM C. crescentus activity was either improved or mildly attenuated with substrates having one to three mismatched bp within or adjacent to the recognition site, but only if the strand undergoing methylation is left unchanged. By comparison, single-mismatched substrates resulted in up to 106-fold losses of activity with α (Dam) and γ-class (M.HhaI) DNA methyltransferases. We found that CcrM C. crescentus has a greatly expanded DNA-interaction surface, covering six nucleotides on the 5' side and eight nucleotides on the 3' side of its recognition site. Such a large interface may contribute to the enzyme's high sequence fidelity. CcrM C. crescentus displayed the same sequence discrimination with single-stranded substrates, and a surprisingly large (>107-fold) discrimination against ssRNA was largely due to the presence of two or more riboses within the cognate (DNA) site but not outside the site. Results from C-terminal truncations and point mutants supported our hypothesis that the recently identified C-terminal, 80-residue segment is essential for dsDNA recognition but is not required for single-stranded substrates. CcrM orthologs from Agrobacterium tumefaciens and Brucella abortus share some of these newly discovered features of the C. crescentus enzyme, suggesting that the recognition mechanism is conserved. In summary, CcrM C. crescentus uses a previously unknown DNA recognition mechanism.