A major role for human (h)CXCL8 (interleukin-8) in the pathobiology of myelofibrosis (MF) has been suggested by observations indicating that MF megakaryocytes express increased levels of hCXCL8 and ...that plasma levels of this cytokine in MF patients are predictive of poor patient outcomes. Here, we demonstrate that, in addition to high levels of TGF-β, the megakaryocytes from the bone marrow of the
Gata1
low
mouse model of myelofibrosis express high levels of murine (m)CXCL1, the murine equivalent of hCXCL8, and its receptors CXCR1 and CXCR2. Treatment with the CXCR1/R2 inhibitor, Reparixin in aged-matched
Gata1
low
mice demonstrated reductions in bone marrow and splenic fibrosis. Of note, the levels of fibrosis detected using two independent methods (Gomori and reticulin staining) were inversely correlated with plasma levels of Reparixin. Immunostaining of marrow sections indicated that the bone marrow from the Reparixin-treated group expressed lower levels of TGF-β1 than those expressed by the bone marrow from vehicle-treated mice while the levels of mCXCL1, and expression of CXCR1 and CXCR2, were similar to that of vehicle-treated mice. Moreover, immunofluorescence analyses performed on bone marrow sections from
Gata1
low
mice indicated that treatment with Reparixin induced expression of GATA1 while reducing expression of collagen III in megakaryocytes. These data suggest that in
Gata1
low
mice, Reparixin reduces fibrosis by reducing TGF-β1 and collagen III expression while increasing GATA1 in megakaryocytes. Our results provide a preclinical rationale for further evaluation of this drug alone and in combination with current JAK inhibitor therapy for the treatment of patients with myelofibrosis.
To document the preservation of hearing after electroacoustic (EAS) cochlear reimplantation and to report on a method of managing recurrent air accumulation under the posterior skin flap.
...Retrospective case report.
A single patient report.
After successful EAS cochlear implantation with hearing preservation, patient developed recurrent air accumulation under his posterior flap and a subsequent device failure. The patient was reimplanted using EAS protocol and a myringotomy tube used to prevent reaccumulation of air.
Preservation of hearing.
Hearing was preserved after reimplantation, and air accumulation was avoided.
Hearing can be preserved in EAS reimplantation using EAS surgical techniques. Air accumulation can be avoided or treated with a myringotomy tube.
Although Central America is one of the most biologically diverse regions in the world, booming road construction is driving roadkill mortality that threatens to alter the demography, genetic ...diversity, and viability of wild mammalian populations. Costa Rica has the highest road density in Central America, but the effectiveness of wildlife crossings in mitigating roadkill mortality has not been assessed with controlled experimental studies. Hacienda Baru National Wildlife Refuge is located along a critical biological corridor bisected by one of the busiest highways in the country. The first wildlife underpasses in Costa Rica were built here in 2010 as part of the expansion of Route 34 and subsequently documented by camera-trap and roadkill surveys. Using a control-impact design, we demonstrate a considerable reduction in wildlife mortality in the presence of the crossing structures compared with controls, with the underpasses and overpasses eventually used by 21 mammalian species. Some species made use of the structures right away, while others took over a year to learn to use them. This is the first controlled study in Central America to document the effectiveness of wildlife crossings and provides evidence that well-designed mitigation structures can contribute to wildlife-friendly roadways.
Efforts to change the fate of human hematopoietic stem cells (HSCs) and progenitor cells (HPCs) in vitro have met with limited success. We hypothesized that previously utilized in vitro conditions ...might result in silencing of genes required for the maintenance of primitive HSCs/HPCs. DNA methylation and histone deacetylation are components of an epigenetic program that regulates gene expression. Using pharmacologic agents in vitro that might possibly interfere with DNA methylation and histone deacetylation, we attempted to maintain and expand cells with phenotypic and functional characteristics of primitive HSCs/HPCs. Human marrow CD34+ cells were exposed to a cytokine cocktail favoring differentiation in combination with 5aza 2′deoxycytidine (5azaD) and trichostatin A (TSA), resulting in a significant expansion of a subset of CD34+ cells that possessed phenotypic properties as well as the proliferative potential characteristic of primitive HSCs/HPCs. In addition, 5azaD- and TSA-pretreated cells but not the CD34+ cells exposed to cytokines alone retained the ability to repopulate immunodeficient mice. Our findings demonstrate that 5azaD and TSA can be used to alter the fate of primitive HSCs/HPCs during in vitro culture.
Slurries are often used in chemical and pharmaceutical manufacturing processes but present challenging online measurement and monitoring problems. In this paper, a novel multivariate kinetic modeling ...application is described that provides calibration-free estimates of time-resolved profiles of the solid and dissolved fractions of a substance in a model slurry system. The kinetic model of this system achieved data fusion of time-resolved spectroscopic measurements from two different kinds of fiber-optic probes. Attenuated total reflectance UV–vis (ATR UV–vis) and diffuse reflectance near-infrared (NIR) spectra were measured simultaneously in a small-scale semibatch reactor. A simplified comprehensive kinetic model was then fitted to the time-resolved spectroscopic data to determine the kinetics of crystallization and the kinetics of dissolution for online monitoring and quality control purposes. The parameters estimated in the model included dissolution and crystal growth rate constants, as well as the dissolution rate order. The model accurately estimated the degree of supersaturation as a function of time during conditions when crystallization took place and accurately estimated the degree of undersaturation during conditions when dissolution took place.
The purpose of this study was to identify major characteristics of children and youth with mental health problems who have contact with police officers and to determine which variables lead to the ...highest probability of police intervention and if there are differences between children and youth compared to adults. Two samples were taken from data obtained from the use of a new police brief mental health screener (interRAI BMHS) in a large southwestern Ontario city between April 2016 and April 2019: 619 cases under age 18 and 4,084 cases over age 18. Univariate and bivariate analysis revealed that all 23 variables on the BMHS were significantly associated with police intervention except for intoxication by drugs or alcohol, squalid home environment, and refusal to take prescribed medication. Variables with the highest odds of police intervention included hallucinations, diminished cognitive skills for daily decision-making, and family or others concerned for potential self-harm. Logistic regression analysis indicated that the variables most predictive of police intervention were hallucinations, lack of insight into their own mental health problems, violent ideation, violence to others, self-injurious attempt in the last 7 days, suicide plan, diminished cognitive skills for daily decision-making, and family or others concerned for self-harm. As to the differences between under and over age 18, adults had higher frequencies of intoxication, hallucinations, delusions, pressured speech, and abnormal thoughts, while under age 18 had slightly higher frequency of socially inappropriate/disruptive behaviour. Risk of harm variables were high in both groups; however, they were clearly higher in the under age 18 group, in particular self-injurious attempt in the last 7 days. The results of this study indicate that there are distinct differences between why police officers intervene with children and youth as opposed to adults which should be reflected in police training and intervention policy.
By single-cell transcriptome profiling of human yolk sacs and fetal livers, Wang et al. (2021) (in this issue of Cell Stem Cell) track two alternative routes for differentiation of megakaryocytes. ...The authors have shown that these megakaryocytes have hemostatic- and HSC-supporting functions, and that hESC-derived thrombospondin1-positive endothelial cells are capable of generating megakaryocytes in vitro.
By single-cell transcriptome profiling of human yolk sacs and fetal livers, Wang et al. (2021) (in this issue of Cell Stem Cell) track two alternative routes for differentiation of megakaryocytes. The authors have shown that these megakaryocytes have hemostatic- and HSC-supporting functions, and that hESC-derived thrombospondin1-positive endothelial cells are capable of generating megakaryocytes in vitro.
Myeloproliferative neoplasm-blast phase (MPN-BP) is a form of acute leukemia which is distinct from de novo acute myeloid leukemia with each entity being characterized by specific complex cytogenetic ...abnormalities and myeloid gene mutational patterns. MPN-BP patients have a particularly dismal prognosis with a medium overall survival of 5.8 months with currently available therapies. Large-scale sequencing studies have unraveled the mutational landscape of the chronic MPNs and MPN-BP, demonstrating importance of clonal heterogeneity and the role of somatic mutations in disease progression and their use to determine patient outcomes. JAK inhibitors represent the standard of care for intermediate/high-risk MF patients and have been shown to improve clinical symptoms. However, this therapeutic approach leads to a modest reduction in the variant allele frequency of the known MPN driver mutations in most patients and does not substantially delay or prevent the evolution to MPN-BP. In this article, we will review molecular mechanisms driving the progression from chronic MPNs to a BP, the impact of genetic changes on MPN-BP evolution, and the role of clonal evolution in response to JAK inhibitor therapy and disease progression. We will also discuss our ongoing functional studies of cells responsible for the development of MPN-BP.
expansion strategies of human hematopoietic stem cell (HSC) grafts with suboptimal stem cell dose have emerged as promising strategies for improving outcomes of HSC transplantation in patients with ...hematological malignancies. While exposure of HSCs to
cultures expands the number of phenotypically identifiable HSCs, it frequently alters the transcriptomic and metabolic profiles, therefore, compromising their long-term (LT) hematopoietic reconstitution capacity. Within the heterogeneous pool of expanded HSCs, the precise phenotypic, transcriptomic and metabolic profile and thus, the identity of HSCs that confer LT repopulation potential remains poorly described. Utilizing valproic acid (VPA) in
cultures of umbilical cord blood (UCB)-CD34
cells, we demonstrate that expanded HSCs phenotypically marked by expression of the stem cell markers CD34, CD90 and EPCR (CD201) are highly enriched for LT-HSCs. Furthermore, we report that low mitochondrial membrane potential, and, hence, mitochondrial activity distinguishes LT-HSCs within the expanded pool of phenotypically defined HSCs. Remarkably, such reduced mitochondrial activity is restricted to cells with the highest expression levels of CD34, CD90 and EPCR phenotypic markers. Together, our findings reveal that high expression of CD34, CD90 and EPCR in conjunction with low mitochondrial activity is critical for identification of functional LT-HSCs generated within
expansion cultures.
PDF
