2,138 research outputs found
Star Formation, Radio Sources, Cooling X-ray Gas, and Galaxy Interactions in the Brightest Cluster Galaxy in 2A0335+096
We present deep emission-line imaging taken with the SOAR Optical Imaging
Camera of the brightest cluster galaxy (BCG) in the nearby (z=0.035) X-ray
cluster 2A0335+096. We analyze long-slit optical spectroscopy, archival VLA,
Chandra X-ray, and XMM UV data. 2A0335+096 is a bright, cool-core X-ray
cluster, once known as a cooling flow. Within the highly disturbed core
revealed by Chandra X-ray observations, 2A0335+096 hosts a highly structured
optical emission-line system. The redshift of the companion is within 100 km/s
of the BCG and has certainly interacted with the BCG, and is likely bound to
it. The comparison of optical and radio images shows curved filaments in
H-alpha emission surrounding the resolved radio source. The velocity structure
of the emission-line bar between the BCG nucleus and the companion galaxy
provides strong evidence for an interaction between the two in the last ~50
Myrs. The age of the radio source is similar to the interaction time, so this
interaction may have provoked an episode of radio activity. We estimate a star
formation rate of >7 solar mass/yr based on the Halpha and archival UV data, a
rate similar to, but somewhat lower than, the revised X-ray cooling rate of
10-30 solar masses/year estimated from XMM spectra by Peterson & workers. The
Halpha nebula is limited to a region of high X-ray surface brightness and cool
X-ray temperature. The detailed structures of H-alpha and X-ray gas differ. The
peak of the X-ray emission is not the peak of H-alpha emission, nor does it lie
in the BCG. The estimated age of the radio lobes and their interaction with the
optical emission-line gas, the estimated timescale for depletion and
accumulation of cold gas, and the dynamical time in the system are all similar,
suggesting a common trigger mechanism.Comment: Accepted AJ, July 2007 publication. Vol 134, p. 14-2
Nonparametric Bayesian inference for perturbed and orthologous gene regulatory networks
Motivation: The generation of time series transcriptomic datasets collected under multiple experimental conditions has proven to be a powerful approach for disentangling complex biological processes, allowing for the reverse engineering of gene regulatory networks (GRNs). Most methods for reverse engineering GRNs from multiple datasets assume that each of the time series were generated from networks with identical topology. In this study, we outline a hierarchical, non-parametric Bayesian approach for reverse engineering GRNs using multiple time series that can be applied in a number of novel situations including: (i) where different, but overlapping sets of transcription factors are expected to bind in the different experimental conditions; that is, where switching events could potentially arise under the different treatments and (ii) for inference in evolutionary related species in which orthologous GRNs exist. More generally, the method can be used to identify context-specific regulation by leveraging time series gene expression data alongside methods that can identify putative lists of transcription factors or transcription factor targets.
Results: The hierarchical inference outperforms related (but non-hierarchical) approaches when the networks used to generate the data were identical, and performs comparably even when the networks used to generate data were independent. The method was subsequently used alongside yeast one hybrid and microarray time series data to infer potential transcriptional switches in Arabidopsis thaliana response to stress. The results confirm previous biological studies and allow for additional insights into gene regulation under various abiotic stresses.
Availability: The methods outlined in this article have been implemented in Matlab and are available on request
Differential Regulation of Primitive Myelopoiesis in the Zebrafish by Spi-1/Pu.1 and C/ebp1
The zebrafish has become a powerful tool for analysis of vertebrate hematopoiesis. Zebrafish, unlike mammals, have a robust primitive myeloid pathway that generates both granulocytes and macrophages. It is not clear how this unique primitive myeloid pathway relates to mammalian definitive hematopoiesis. In this study, we show that the two myeloid subsets can be distinguished using RNA in situ hybridization. Using a morpholino-antisense gene knockdown approach, we have characterized the hematopoietic defects resulting from knockdown of the myeloid transcription factor gene pu.1 and the unique zebrafish gene c/ebp1. Severe reduction of pu.1 resulted in complete loss of primitive macrophage development, with effects on granulocyte development only with maximal knockdown. Reduction of c/ebp1 did not ablate initial macrophage or granulocyte development, but resulted in loss of expression of the secondary granule gene lys C. These data reveal strong functional conservation of pu.1 between zebrafish primitive myelopoiesis and mammalian definitive myelopoiesis. Further, these results are consistent with a conserved role between c/ebp1 and mammalian C/EBPE, whose ortholog in zebrafish has not been identified. These studies validate the examination of zebrafish primitive myeloid development as a model for human myelopoiesis, and form a framework for identification and analysis of myeloid mutants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63190/1/zeb.2007.0505.pd
Metabolic Responses of Two Assisted CPR Devices Versus Manual CPR during 1-Person CPR
Prolonged, one-person CPR is exhausting and associated with decayed CPR quality over time. Active compression-decompression-CPR (ACD-CPR) requires the rescuer to actively work during both phases of CPR. We evaluated the metabolic cost of manual CPR (M-CPR), ACD-CPR1, and ACD-CPR2 (with adhesive pad) during a 10-min resuscitation period. We hypothesized that the metabolic cost for the devices would be similar to M-CPR. Twenty (10 female) participants (23.5±3.5y, 165.8±25.6cm, 72.5±12.2kg) completed 3 randomized trials with performance feedback by investigators. Expired air was analyzed for estimations of metabolic cost via indirect calorimetry. Participants rested for 10 minutes before the baseline data collection followed by 10 min of CPR to simulate one-person CPR. Treatment effects were observed for VO2, METS, VCO2, HR, RR, blood lactate, and RPE. No such effect was observed for RQ, SBP, or DBP. VO2 (ml/kgBW/min) was significantly higher with ACD-CPR1 (17.8±1.4) vs. MCPR and ACD-CPR2 (15.9±0.9 and 14.2±1.1, respectively). Metabolic equivalent (MET) was significantly lower with ACD-CPR2 (4.1±0.3) vs. MCPR and ACD-CPR1 (4.7±0.3 and 5.1±0.4, respectively). All three groups’ blood lactate data differed significantly with ACD-CPR1 \u3e M-CPR \u3e ACD-CPR2. The RR required by the ACD-CPR1 during a 10 min CPR simulation is significantly higher than the ACD-CPR2 and M-CPR. No group differences were observed for RQ, SBP, or DBP. CPR performance metrics were averaged over the 10-min resuscitation period. RPE was significantly higher following ACD-CPR1 compared to both M-CPR and ACD-CPR2. The metabolic work required by the ACD-CPR2 during 10-min simulated one-person resuscitation (80/min) is far less than the ACD-CPR1. However, the ACD-CPR2 metabolic cost is similar to that of M-CPR, despite the latter method’s higher rate of compressions (110/min) and passive decompressions
Radiological and clinical features of vein of Galen malformations.
BackgroundVein of Galen malformations (VOGMs) are rare and complex congenital arteriovenous fistulas. The clinical and radiological features of VOGMs and their relation to clinical outcomes are not fully characterized.ObjectiveTo examine the clinical and radiological features of VOGMs and the predictors of outcome in patients.MethodsWe retrospectively reviewed the available imaging and medical records of all patients with VOGMs treated at the University of California, San Francisco between 1986 and 2013. Radiological and clinical features were identified. We applied the modified Rankin Scale to determine functional outcome by chart review. Predictors of outcome were assessed by χ(2) analyses.ResultsForty-one cases were confirmed as VOGM. Most patients (78%) had been diagnosed with VOGM in the first year of life. Age at treatment was bimodally distributed, with predominantly urgent embolization at <10 days of age and elective embolization after 1 year of age. Patients commonly presented with hydrocephalus (65.9%) and congestive heart failure (61.0%). Mixed-type (31.7%) VOGM was more common in our cohort than purely mural (29.3%) or choroidal (26.8%) types. The most common feeding arteries were the choroidal and posterior cerebral arteries. Transarterial embolization with coils was the most common technique used to treat VOGMs at our institution. Functional outcome was normal or only mildly disabled in 50% of the cases at last follow-up (median=3 years, range=0-23 years). Younger age at first diagnosis, congestive heart failure, and seizures were predictive of adverse clinical outcome. The survival rate in our sample was 78.0% and complete thrombosis of the VOGM was achieved in 62.5% of patients.ConclusionsVOGMs continue to be challenging to treat and manage. Nonetheless, endovascular approaches to treatment are continuing to be refined and improved, with increasing success. The neurodevelopmental outcomes of affected children whose VOGMs are treated may be good in many cases
Pediatric intracranial dural arteriovenous fistulas: age-related differences in clinical features, angioarchitecture, and treatment outcomes.
OBJECTIVE Intracranial dural arteriovenous fistulas (DAVFs) are rare in children. This study sought to better characterize DAVF presentation, angioarchitecture, and treatment outcomes. METHODS Children with intracranial DAVFs between 1986 and 2013 were retrospectively identified from the neurointerventional database at the authors' institution. Demographics, clinical presentation, lesion angioarchitecture, treatment approaches, angiographic outcomes, and clinical outcomes were assessed. RESULTS DAVFs constituted 5.7% (22/423) of pediatric intracranial arteriovenous shunting lesions. Twelve boys and 10 girls presented between 1 day and 18 years of age; boys presented at a median of 1.3 years and girls presented at a median of 4.9 years. Four of 8 patients ≤ 1 year of age presented with congestive heart failure compared with 0/14 patients > 1 year of age (p = 0.01). Five of 8 patients ≤ 1 year old presented with respiratory distress compared with 0/14 patients > 1 year old (p = 0.0021). Ten of 14 patients > 1 year old presented with focal neurological deficits compared with 0/8 patients ≤ 1 year old (p = 0.0017). At initial angiography, 16 patients harbored a single intracranial DAVF and 6 patients had 2-6 DAVFs. Eight patients (38%) experienced DAVF obliteration by the end of treatment. Good clinical outcome (modified Rankin Scale score 0-2) was documented in 77% of patients > 1 year old at presentation compared with 57% of patients ≤ 1 year old at presentation. Six patients (27%) died. CONCLUSIONS Young children with DAVFs presented predominantly with cardiopulmonary symptoms, while older children presented with focal neurological deficits. Compared with other pediatric vascular shunts, DAVFs had lower rates of angiographic obliteration and poorer clinical outcomes
Feasibility of Multiple Repeat Gamma Knife Radiosurgeries for Trigeminal Neuralgia: A Case Report and Review of the Literature
Treatment options for trigeminal neuralgia (TN) must be customized for the individual patient, and physicians must be aware of the medical, surgical, and radiation treatment modalities to prescribe optimal treatment courses for specific patients. The following case illustrates the potential for gamma knife radiosurgery (GKRS) to be repeated multiple times for the purpose of achieving facial pain control in cases of TN that have been refractory to other medical and surgical options, as well as prior GKRS. The patient described failed to achieve pain control with initial GKRS, as well as medical and surgical treatments, but experienced significant pain relief for a period of time with a second GKRS procedure and later underwent a third procedure. Only a small subset of patients have reportedly undergone more than two GKRS for TN; thus, further research and long-term clinical followup will be valuable in determining its usefulness in specific clinical situations
Long-Term Survival after Gamma Knife Radiosurgery in a Case of Recurrent Glioblastoma Multiforme: A Case Report and Review of the Literature
The management of recurrent glioblastoma is highly challenging, and treatment outcomes remain uniformly poor. Glioblastoma is a highly infiltrative tumor, and complete surgical resection of all microscopic extensions cannot be achieved at the time of initial diagnosis, and hence local recurrence is observed in most patients. Gamma Knife radiosurgery has been used to treat these tumor recurrences for select cases and has been successful in prolonging the median survival by 8–12 months on average for select cases. We present the unique case of a 63-year-old male with multiple sequential recurrences of glioblastoma after initial standard treatment with surgery followed by concomitant external beam radiation therapy and chemotherapy (temozolomide). The patient was followed clinically as well as with surveillance MRI scans at every 2-3-month intervals. The patient underwent Gamma Knife radiosurgery three times for 3 separate tumor recurrences, and the patient survived for seven years following the initial diagnosis with this aggressive treatment. The median survival in patients with recurrent glioblastoma is usually 8–12 months after recurrence, and this unique case illustrates that aggressive local therapy can lead to long-term survivors in select situations. We advocate that each patient treatment at the time of recurrence should be tailored to each clinical situation and desire for quality of life and improved longevity
Gamma knife radiosurgery for movement disorders: a concise review of the literature
Medication is the predominant method for the management of patients with movement disorders. However, there is a fraction of patients who experience limited relief from pharmaceuticals or experience bothersome side-effects of the drugs. Deep brain stimulation (DBS) and surgical lesioning of the thalamus and basal ganglia are respected neurosurgical procedures, with valued success rates and a very low incidence of complications. Despite these positive outcomes, DBS and surgical lesioning procedures are contraindicated for some patients. Stereotactic radiosurgery with the Gamma Knife (GK) has been used as a lesioning technique for patients seeking a non-invasive treatment alternative and for medication-intolerable patients, who are unable to undergo DBS or lesioning due to comorbid medical conditions. Tremors of various etiologies are treated using GK thalamotomy, which targets the ventralis intermedius nucleus. GK thalamotomy produces favorable outcomes when treating tremors, with success rates ranging from 80-100%. In contrast, GK pallidotomy targets the internal globus pallidus, and is used in treating bradykinesia, rigidity, and dyskinesia. Although radiosurgery has proven beneficial for tremors, radiosurgical pallidotomy for bradykinesia, rigidity, and dyskinesia remains questionable, with mixed success rates in the literature that ranges from 0-87%. We suggest that GK thalamotomy be offered along with other neurosurgical approaches as a feasible treatment option to patients who prefer the non-invasive nature of radiosurgery and to those who are unqualified candidates for the neurosurgical alternatives. Also, we advise that patients with bradykinesia, rigidity, and dyskinesia be educated about the variability in the literature pertaining to GK pallidotomy before proceeding with treatment
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