221 research outputs found
FACS purification and transcriptome analysis of drosophila neural stem cells reveals a role for Klumpfuss in self-renewal
Drosophila neuroblasts (NBs) have emerged as a model for stem cell biology that is ideal for genetic analysis but is limited by the lack of cell-type-specific gene expression data. Here, we describe a method for isolating large numbers of pure NBs and differentiating neurons that retain both cell-cycle and lineage characteristics. We determine transcriptional profiles by mRNA sequencing and identify 28 predicted NB-specific transcription factors that can be arranged in a network containing hubs for Notch signaling, growth control, and chromatin regulation. Overexpression and RNA interference for these factors identify Klumpfuss as a regulator of self-renewal. We show that loss of Klumpfuss function causes premature differentiation and that overexpression results in the formation of transplantable brain tumors. Our data represent a valuable resource for investigating Drosophila developmental neurobiology, and the described method can be applied to other invertebrate stem cell lineages as well
Recommended from our members
Serum 1,3-Beta-D-Glucan Values During and After Laparoscopic and Open Intestinal Surgery.
Background1,3-beta-D Glucan (BDG) assay has good accuracy for distinguishing patients with invasive fungal infections from patients without. Some procedures and medications affect BDG levels, resulting in false-positive BDG results. The extent of intestinal surgery on BDG kinetics is unknown. We evaluated the influence of laparoscopic and open intestinal surgery on peri- and postsurgical serum BDG values.MethodsBDG was determined in 346 samples from 50 patients undergoing laparoscopic (24) or open (26) intestinal surgery at the following time points: after insertion of arterial but before skin incision, after skin incision but before dissection of the intestinal mucosa, after completion of anastomosis, after completion of skin sutures, in the evening after surgery, day 2 after surgery, 4-5 days after surgery.ResultsBDG was positive (ie, concentration ≥80 pg/mL) in 54% to 61% of patients during laparoscopic and open surgery (highest rates after completion of skin sutures). BDG was still positive in 12% (open) to 17% (laparoscopic) of patients without any suspected or proven fungal infection or anastomotic leakage 4-5 days after surgery. After completion of gut anastomosis, the BDG increase was higher in open compared with laparoscopic intestinal surgery.ConclusionsThe value of positive BDG tests in the perioperative setting up to 5 days postsurgery seems to be limited due to BDG elevations from intestinal surgical procedures
First histological observations on the incorporation of a novel nanocrystalline hydroxyapatite paste OSTIM(® )in human cancellous bone
BACKGROUND: A commercially available nanocrystalline hydroxyapatite paste Ostim(® )has been reported in few recent studies to surpass other synthetic bone substitutes with respect to the observed clinical results. However, the integration of this implantable material has been histologically evaluated only in animal experimental models up to now. This study aimed to evaluate the tissue incorporation of Ostim(® )in human cancellous bone after reconstructive bone surgery for trauma. METHODS: Biopsy specimens from 6 adult patients with a total of 7 tibial, calcaneal or distal radial fractures were obtained at the time of osteosynthesis removal. The median interval from initial operation to tissue sampling was 13 (range 3–15) months. Samples were stained with Masson-Goldner, von Kossa, and toluidine blue. Osteoid volume, trabecular width and bone volume, and cortical porosity were analyzed. Samples were immunolabeled with antibodies against CD68, CD56 and human prolyl 4-hydroxylase to detect macrophages, osteoblasts, and fibroblasts, respectively. TRAP stainings were used to identify osteoclasts. RESULTS: Histomorphometric data indicated good regeneration with normal bone turnover: mean osteoid volume was 1.93% of the trabecular bone mass, trabecular bone volume – 28.4%, trabecular width – 225.12 μm, and porosity index – 2.6%. Cortical and spongious bone tissue were well structured. Neither inflammatory reaction, nor osteofibrosis or osteonecrosis were observed. The implanted material was widely absorbed. CONCLUSION: The studied nanocrystalline hydroxyapatite paste showed good tissue incorporation. It is highly biocompatible and appears to be a suitable bone substitute for juxtaarticular comminuted fractures in combination with a stable screw-plate osteosynthesis
Neural circuitry of a polycystin-mediated hydrodynamic startle response for predator avoidance
This is the final version. Available on open access from eLife via the DOI in this recordStartle responses triggered by aversive stimuli including predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behaviour. Upon encountering water vibrations, larvae of the annelid Platynereis close their locomotor cilia and simultaneously raise the parapodia. The response is mediated by collar receptor neurons expressing the polycystins PKD1-1 and PKD2-1. CRISPR-generated PKD1-1 and PKD2-1 mutant larvae do not startle and fall prey to a copepod predator at a higher rate. Reconstruction of the whole-body connectome of the collar-receptor-cell circuitry revealed converging feedforward circuits to the ciliary bands and muscles. The wiring diagram suggests circuit mechanisms for the intersegmental and left-right coordination of the response. Our results reveal how polycystin-mediated mechanosensation can trigger a coordinated whole-body effector response involved in predator avoidance.European Research CouncilDeutsche Forschungsgemein- schaftMarie Curie Intra-European fellowshipCentre for Ocean Lif
Desiccation cracks provide evidence of lake drying on Mars, Sutton Island member, Murray formation, Gale Crater
Mars Science Laboratory (MSL) Curiosity rover data are used to describe the morphology of desiccation cracks observed in ancient lacustrine strata at Gale crater, Mars, and to interpret their paleoenvironmental setting. The desiccation cracks indicate subaerial exposure of lacustrine facies in the Sutton Island member of the Murray formation. In association with ripple cross-stratification and possible eolian cross-bedding, these facies indicate a transition from longer-lived perennial lakes recorded by older strata to younger lakes characterized by intermittent exposure. The transition from perennial to episodically exposed lacustrine environments provides evidence for local to regional climate change that can help constrain Mars climate models
Benefit of abciximab in patients with refractory unstable angina in relation to serum troponin T levels
Background: In patients with refractory unstable angina, the platelet glycoprotein IIb/IIIa-receptor antibody abciximab reduces the incidence of cardiac events before and during coronary angioplasty. We investigated whether serum troponin T levels identify patients most likely to benefit from therapy with this drug. Methods: Among 1265 patients with unstable angina who were enrolled in the c7E3 Fab Antiplatelet Therapy in Unstable Refractory Angina (CAPTURE) trial, serum samples drawn at the time of randomization to abciximab or placebo were available from 890 patients; we used these samples for the determination of troponin T and creatine kinase MB levels. Patients with postinfarction angina were not included. Results: Serum troponin T levels at the time of study entry were elevated (above 0.1 ng per milliliter) in 275 patients (30.9 percent). Among patients receiving placebo, the risk of death or nonfatal myocardial infarction was related to troponin T levels. The six-month cumulative event rate was 23.9 percent among patients with elevated troponin T levels, as compared with 7.5 percent among patients without elevated troponin T levels (P<0.001). Among patients treated with abciximab, the respective six-month event rates were 9.5 percent for patients with elevated troponin T levels and 9.4 percent for those without elevated levels. As compared with placebo, the relative risk of death or nonfatal myocardial infarction associated with treatment with abciximab in patients with elevated troponin T levels was 0.32 (95 percent confidence interval, 0.14 to 0.62; P=0.002). The lower event rates in patients receiving abciximab were attributable to a reduction in the rate of myocardial infarction (odds ratio, 0.23; 95 percent confidence interval, 0.12 to 0.49; P<0.001). In patients without elevated troponin T levels, there was no benefit of treatment with respect to the relative risk of death or myocardial infarction at six months (odds ratio, 1.26; 95 percent confidence interval, 0.74 to 2.31; P=0.47). Conclusions: The serum troponin T level, which is considered to be a surrogate marker for thrombus formation, identifies a high-risk subgroup of patients with refractory unstable angina suitable for coronary angioplasty who will particularly benefit from antiplatelet treatment with abciximab
Growth of large-area single- and bi-layer graphene by controlled carbon precipitation on polycrystalline Ni surfaces
We report graphene films composed mostly of one or two layers of graphene
grown by controlled carbon precipitation on the surface of polycrystalline Ni
thin films during atmospheric chemical vapor deposition(CVD). Controlling both
the methane concentration during CVD and the substrate cooling rate during
graphene growth can significantly improve the thickness uniformity. As a
result, one- or two- layer graphene regions occupy up to 87% of the film area.
Single layer coverage accounts for 5-11% of the overall film. These regions
expand across multiple grain boundaries of the underlying polycrystalline Ni
film. The number density of sites with multilayer graphene/graphite (>2 layers)
is reduced as the cooling rate decreases. These films can also be transferred
to other substrates and their sizes are only limited by the sizes of the Ni
film and the CVD chamber. Here, we demonstrate the formation of films as large
as 1 in2. These findings represent an important step towards the fabrication of
large-scale high-quality graphene samples
Prognostic Evaluation of Re-Resection for Recurrent Glioblastoma Using the Novel RANO Classification for Extent of Resection: A Report of the RANO Resect Group
BACKGROUND: The value of re-resection in recurrent glioblastoma remains controversial as a randomized trial that specifies intentional incomplete resection cannot be justified ethically. Here, we aimed to (1) explore the prognostic role of extent of re-resection using the previously proposed Response Assessment in Neuro-Oncology (RANO) classification (based upon residual contrast-enhancing (CE) and non-CE tumor), and to (2) define factors consolidating the surgical effects on outcome.
METHODS: The RANO resect group retrospectively compiled an 8-center cohort of patients with first recurrence from previously resected glioblastomas. The associations of re-resection and other clinical factors with outcome were analyzed. Propensity score-matched analyses were constructed to minimize confounding effects when comparing the different RANO classes.
RESULTS: We studied 681 patients with first recurrence of Isocitrate Dehydrogenase (IDH) wild-type glioblastomas, including 310 patients who underwent re-resection. Re-resection was associated with prolonged survival even when stratifying for molecular and clinical confounders on multivariate analysis; ≤1 cm3 residual CE tumor was associated with longer survival than non-surgical management. Accordingly, maximal resection (class 2) had superior survival compared to submaximal resection (class 3). Administration of (radio-)chemotherapy in the absence of postoperative deficits augmented the survival associations of smaller residual CE tumors. Conversely, supramaximal resection of non-CE tumor (class 1) was not associated with prolonged survival but was frequently accompanied by postoperative deficits. The prognostic role of residual CE tumor was confirmed in propensity score analyses.
CONCLUSIONS: The RANO resect classification serves to stratify patients with re-resection of glioblastoma. Complete resection according to RANO resect classes 1 and 2 is prognostic
Prognostic evaluation of re-resection for recurrent glioblastoma using the novel RANO classification for extent of resection:A report of the RANO resect group
BACKGROUND: The value of re-resection in recurrent glioblastoma remains controversial as a randomized trial that specifies intentional incomplete resection cannot be justified ethically. Here, we aimed to (1) explore the prognostic role of extent of re-resection using the previously proposed Response Assessment in Neuro-Oncology (RANO) classification (based upon residual contrast-enhancing (CE) and non-CE tumor), and to (2) define factors consolidating the surgical effects on outcome. METHODS: The RANO resect group retrospectively compiled an 8-center cohort of patients with first recurrence from previously resected glioblastomas. The associations of re-resection and other clinical factors with outcome were analyzed. Propensity score-matched analyses were constructed to minimize confounding effects when comparing the different RANO classes. RESULTS: We studied 681 patients with first recurrence of Isocitrate Dehydrogenase (IDH) wild-type glioblastomas, including 310 patients who underwent re-resection. Re-resection was associated with prolonged survival even when stratifying for molecular and clinical confounders on multivariate analysis; ≤1 cm3 residual CE tumor was associated with longer survival than non-surgical management. Accordingly, "maximal resection" (class 2) had superior survival compared to "submaximal resection" (class 3). Administration of (radio-)chemotherapy in the absence of postoperative deficits augmented the survival associations of smaller residual CE tumors. Conversely, "supramaximal resection" of non-CE tumor (class 1) was not associated with prolonged survival but was frequently accompanied by postoperative deficits. The prognostic role of residual CE tumor was confirmed in propensity score analyses. CONCLUSIONS: The RANO resect classification serves to stratify patients with re-resection of glioblastoma. Complete resection according to RANO resect classes 1 and 2 is prognostic.</p
Surgical Management and Outcome of Newly Diagnosed Glioblastoma Without Contrast Enhancement (Low-Grade Appearance): A Report of the RANO Resect Group
BACKGROUND: Resection of the contrast-enhancing (CE) tumor represents the standard of care in newly diagnosed glioblastoma. However, some tumors ultimately diagnosed as glioblastoma lack contrast enhancement and have a \u27low-grade appearance\u27 on imaging (non-CE glioblastoma). We aimed to (a) volumetrically define the value of non-CE tumor resection in the absence of contrast enhancement, and to (b) delineate outcome differences between glioblastoma patients with and without contrast enhancement.
METHODS: The RANO resect group retrospectively compiled a global, eight-center cohort of patients with newly diagnosed glioblastoma per WHO 2021 classification. The associations between postoperative tumor volumes and outcome were analyzed. Propensity score-matched analyses were constructed to compare glioblastomas with and without contrast enhancement.
RESULTS: Among 1323 newly diagnosed IDH-wildtype glioblastomas, we identified 98 patients (7.4%) without contrast enhancement. In such patients, smaller postoperative tumor volumes were associated with more favorable outcome. There was an exponential increase in risk for death with larger residual non-CE tumor. Accordingly, extensive resection was associated with improved survival compared to lesion biopsy. These findings were retained on a multivariable analysis adjusting for demographic and clinical markers. Compared to CE glioblastoma, patients with non-CE glioblastoma had a more favorable clinical profile and superior outcome as confirmed in propensity score analyses by matching the patients with non-CE glioblastoma to patients with CE glioblastoma using a large set of clinical variables.
CONCLUSIONS: The absence of contrast enhancement characterizes a less aggressive clinical phenotype of IDH-wildtype glioblastomas. Maximal resection of non-CE tumors has prognostic implications and translates into favorable outcome
- …