Glaucoma is a chronic and progressive eye disease, commonly associated with elevated intraocular pressure (IOP) and characterized by optic nerve degeneration, cupping of the optic disc, and loss of ...retinal ganglion cells (RGCs). The pathological changes in glaucoma are triggered by multiple mechanisms and both mechanical effects and vascular factors are thought to contribute to the etiology of glaucoma. Various studies have shown that endothelin-1 (ET-1), a vasoactive peptide, acting through its G protein coupled receptors, ET
and ET
, plays a pathophysiologic role in glaucoma. However, the mechanisms by which ET-1 contribute to neurodegeneration remain to be completely understood. Our laboratory and others demonstrated that macitentan (MAC), a pan endothelin receptor antagonist, has neuroprotective effects in rodent models of IOP elevation. The current study aimed to determine if oral administration of a dual endothelin antagonist, macitentan, could promote neuroprotection in an acute model of intravitreal administration of ET-1. We demonstrate that vasoconstriction following the intravitreal administration of ET-1 was attenuated by dietary administration of the ET
/ET
dual receptor antagonist, macitentan (5 mg/kg body weight) in retired breeder Brown Norway rats. ET-1 intravitreal injection produced a 40% loss of RGCs, which was significantly lower in macitentan-treated rats. We also evaluated the expression levels of glial fibrillary acidic protein (GFAP) at 24 h and 7 days post intravitreal administration of ET-1 in Brown Norway rats as well as following ET-1 treatment in cultured human optic nerve head astrocytes. We observed that at the 24 h time point the expression levels of GFAP was upregulated (indicative of glial activation) following intravitreal ET-1 administration in both retina and optic nerve head regions. However, following macitentan administration for 7 days after intravitreal ET-1 administration, we observed an upregulation of GFAP expression, compared to untreated rats injected intravitreally with ET-1 alone. Macitentan treatment in ET-1 administered rats showed protection of RGC somas but was not able to preserve axonal integrity and functionality. The endothelin receptor antagonist, macitentan, has neuroprotective effects in the retinas of Brown Norway rats acting through different mechanisms, including enhancement of RGC survival and reduction of ET-1 mediated vasoconstriction.
To evaluate the effect of technical errors (TEs) on the outcomes after repair of femoral neck fractures in young adults.
Multicenter retrospective clinical study.
26 North American Level 1 Trauma ...Centers.
Skeletally mature patients younger than 50 years of age with 492 femoral neck fractures treated between 2005 and 2017.
Operative repair of femoral neck fracture.
The association between TE (malreduction and deviation from optimal technique) and treatment failure (fixation failure, nonunion, malunion, osteonecrosis, malunion, and revision surgery) were examined using logistic regression analysis.
Overall, a TE was observed in 50% (n = 245/492) of operatively managed femoral neck fractures in young patients. Two or more TEs were observed in 10% of displaced fractures. Treatment failure in displaced fractures occurred in 27% of cases without a TE, 56% of cases with 1 TE, and 86% of cases with 2 or more TEs. TEs were encountered less frequently in treatment of nondisplaced fractures compared with displaced fractures (39% vs. 53%, P < 0.001). Although TE(s) in nondisplaced fractures increased the risk of treatment failure and/or major reconstructive surgery (22% vs. 9%, P < 0.001), they were less frequently associated with treatment failure when compared with displaced fractures with a TE (22% vs. 69% P < 0.001).
TEs were found in half of all femoral neck fractures in young adults undergoing operative repair. Both the occurrence and number of TEs were associated with an increased risk for failure of treatment. Preoperative planning for thoughtful and well-executed reduction and fixation techniques should lead to improved outcomes for young patients with femoral neck fractures. This study should also highlight the need for educational forums to address this subject.
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
To evaluate whether augmenting traditional fixation with a femoral neck buttress plate (FNBP) improves clinical outcomes in young adults with high-energy displaced femoral neck fractures.
Multicenter ...retrospective matched cohort comparative clinical study.
Twenty-seven North American Level 1 trauma centers.
Adult patients younger than 55 years who sustained a high-energy (nonpathologic) displaced femoral neck fracture.
Operative reduction and stabilization of a displaced femoral neck fracture with (group 1) and without (group 2) an FNBP.
Complications including failed fixation, nonunion, osteonecrosis, malunion, and need for subsequent major reconstructive surgery (early revision of reduction and/or fixation), proximal femoral osteotomy, or arthroplasty.
Of 478 patients younger than 55 years treated operatively for a displaced femoral neck fracture, 11% (n = 51) had the definitive fixation augmented with an FNBP. One or more forms of treatment failure occurred in 29% (n = 15/51) for group 1 and 49% (209/427) for group 2 ( P < 0.01). When FNBP fixation was used, mini-fragment (2.4/2.7 mm) fixation failed significantly more often than small-fragment (3.5 mm) fixation (42% vs. 5%, P < 0.01). Irrespective of plate size, anterior and anteromedial plates failed significantly more often than direct medial plates (75% and 33% vs. 9%, P < 0.001).
The use of a femoral neck buttress plate to augment traditional fixation in displaced femoral neck fractures is associated with improved clinical outcomes, including lower rates of failed fixation, nonunion, osteonecrosis, and need for secondary reconstructive surgery. The benefits of this technique are optimized when a small-fragment (3.5 mm) plate is applied directly to the medial aspect of the femoral neck, avoiding more anterior positioning .
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
Most mutations in cancer genomes are thought to be acquired after the initiating event, which may cause genomic instability and drive clonal evolution. However, for acute myeloid leukemia (AML), ...normal karyotypes are common, and genomic instability is unusual. To better understand clonal evolution in AML, we sequenced the genomes of M3-AML samples with a known initiating event (PML-RARA) versus the genomes of normal karyotype M1-AML samples and the exomes of hematopoietic stem/progenitor cells (HSPCs) from healthy people. Collectively, the data suggest that most of the mutations found in AML genomes are actually random events that occurred in HSPCs before they acquired the initiating mutation; the mutational history of that cell is “captured” as the clone expands. In many cases, only one or two additional, cooperating mutations are needed to generate the malignant founding clone. Cells from the founding clone can acquire additional cooperating mutations, yielding subclones that can contribute to disease progression and/or relapse.
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► Normal HSPCs contain random background mutations that increase with aging ► AML genomes contain hundreds of mutations, but very few are recurrent ► Comparison of M1 and M3 AML genomes identifies initiating versus cooperating mutations ► Most AML mutations are probably background events in HSPCs, “captured” by cloning
Comparison of the genomes of two groups of patients, each with a different form of AML, allows the resolution of potential driver and cooperating mutations in each disease and reveals that the genetic history of all AML cases is marked by random, benign mutations acquired by normal HSPCs as a function of age.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Most patients with acute myeloid leukaemia (AML) die from progressive disease after relapse, which is associated with clonal evolution at the cytogenetic level. To determine the mutational spectrum ...associated with relapse, we sequenced the primary tumour and relapse genomes from eight AML patients, and validated hundreds of somatic mutations using deep sequencing; this allowed us to define clonality and clonal evolution patterns precisely at relapse. In addition to discovering novel, recurrently mutated genes (for example, WAC, SMC3, DIS3, DDX41 and DAXX) in AML, we also found two major clonal evolution patterns during AML relapse: (1) the founding clone in the primary tumour gained mutations and evolved into the relapse clone, or (2) a subclone of the founding clone survived initial therapy, gained additional mutations and expanded at relapse. In all cases, chemotherapy failed to eradicate the founding clone. The comparison of relapse-specific versus primary tumour mutations in all eight cases revealed an increase in transversions, probably due to DNA damage caused by cytotoxic chemotherapy. These data demonstrate that AML relapse is associated with the addition of new mutations and clonal evolution, which is shaped, in part, by the chemotherapy that the patients receive to establish and maintain remissions.
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DOBA, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
DNMT3A Mutations in Acute Myeloid Leukemia Ley, Timothy J; Ding, Li; Walter, Matthew J ...
The New England journal of medicine,
12/2010, Volume:
363, Issue:
25
Journal Article
Peer reviewed
Open access
Whole-genome sequence analysis of cells from a patient with acute myeloid leukemia (AML) revealed a mutation in DNMT3A, which encodes an enzyme that methylates DNA. Subsequent analyses showed that ...DNMT3A was mutated in 33.7% of patients with AML with an intermediate-risk cytogenetic profile.
Whole-genome sequencing is an unbiased approach for discovering somatic variations in cancer genomes. We recently reported the DNA sequence and analysis of the genomes of two patients with acute myeloid leukemia (AML) with a normal karyotype.
1
,
2
We did not find new recurring mutations in the first study but did observe a recurrent mutation in
IDH1,
encoding isocitrate dehydrogenase 1, in the second study.
2
Subsequent work has confirmed and extended this finding, showing that mutations in
IDH1
and related gene
IDH2
are highly recurrent in patients with an intermediate-risk cytogenetic profile (20 to 30% frequency) and are associated with a . . .
A comparison of the genomic sequence of a tumor sample from a patient with acute myeloid leukemia (AML) and that of a normal skin sample from the same patient revealed an estimated 750 somatic ...mutations, of which 12 were in the coding sequences of genes and 52 were in conserved regions or regions with regulatory potential. Four mutations were found to be recurrent in AML, including mutations in
NRAS, NPM1, IDH1,
and a conserved region on chromosome 10.
A comparison of the genomic sequence of a tumor sample from a patient with acute myeloid leukemia (AML) and that of a normal skin sample from the same patient revealed an estimated 750 somatic mutations. Four mutations were found to be recurrent in AML.
Acute myeloid leukemia (AML) is a clonal hematopoietic disease caused by both inherited and acquired genetic alterations.
1
–
3
Current AML classification and prognostic systems incorporate genetic information but are limited to known abnormalities that have previously been identified with the use of cytogenetics, array comparative genomic hybridization (CGH), gene-expression profiling, and the resequencing of candidate genes (see the Glossary).
The karyotyping of AML cells remains the most powerful predictor of the outcome in patients with AML and is routinely used by clinicians.
4
,
5
As an adjunct to cytogenetic studies, small subcytogenetic amplifications and deletions can be identified with the use . . .
Neural stem cells (NSCs) must exit quiescence to produce neurons; however, our understanding of this process remains constrained by the technical limitations of current technologies. Fluorescence ...lifetime imaging (FLIM) of autofluorescent metabolic cofactors has been used in other cell types to study shifts in cell states driven by metabolic remodeling that change the optical properties of these endogenous fluorophores. Using this non-destructive, live-cell, and label-free strategy, we found that quiescent NSCs (qNSCs) and activated NSCs (aNSCs) have unique autofluorescence profiles. Specifically, qNSCs display an enrichment of autofluorescence localizing to a subset of lysosomes, which can be used as a graded marker of NSC quiescence to predict cell behavior at single-cell resolution. Coupling autofluorescence imaging with single-cell RNA sequencing, we provide resources revealing transcriptional features linked to deep quiescence and rapid NSC activation. Together, we describe an approach for tracking mouse NSC activation state and expand our understanding of adult neurogenesis.
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•Autofluorescence is a live-cell and label-free marker of NSC quiescence•Lysosome-localized autofluorescence is enriched in quiescent NSCs•NSC autofluorescence predicts cell behavior in vitro and ex vivo•Autofluorescence imaging paired with scRNA sequencing can reveal quiescence substates
Classical approaches for determining neural stem cell activation state are technically limited, often involving confounding exogenous reagents or sample destruction through lysis or fixation. Overcoming this barrier, Morrow et al. developed a non-destructive, live-cell, and label-free approach for distinguishing quiescent and activated neural stem cells through autofluorescence imaging.
Cognitive decline is a feared aspect of growing old. It is a major contributor to lower quality of life and loss of independence in old age. We investigated the genetic contribution to individual ...differences in nonpathological cognitive ageing in five cohorts of older adults. We undertook a genome-wide association analysis using 549 692 single-nucleotide polymorphisms (SNPs) in 3511 unrelated adults in the Cognitive Ageing Genetics in England and Scotland (CAGES) project. These individuals have detailed longitudinal cognitive data from which phenotypes measuring each individual's cognitive changes were constructed. One SNP--rs2075650, located in TOMM40 (translocase of the outer mitochondrial membrane 40 homolog)--had a genome-wide significant association with cognitive ageing (P=2.5 × 10(-8)). This result was replicated in a meta-analysis of three independent Swedish cohorts (P=2.41 × 10(-6)). An Apolipoprotein E (APOE) haplotype (adjacent to TOMM40), previously associated with cognitive ageing, had a significant effect on cognitive ageing in the CAGES sample (P=2.18 × 10(-8); females, P=1.66 × 10(-11); males, P=0.01). Fine SNP mapping of the TOMM40/APOE region identified both APOE (rs429358; P=3.66 × 10(-11)) and TOMM40 (rs11556505; P=2.45 × 10(-8)) as loci that were associated with cognitive ageing. Imputation and conditional analyses in the discovery and replication cohorts strongly suggest that this effect is due to APOE (rs429358). Functional genomic analysis indicated that SNPs in the TOMM40/APOE region have a functional, regulatory non-protein-coding effect. The APOE region is significantly associated with nonpathological cognitive ageing. The identity and mechanism of one or multiple causal variants remain unclear.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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